【０００１】
【発明の属する技術分野】
本発明は光軸の前後方向の近傍にそれぞれ配置された拡散光源から光軸に沿って射出された拡散光束を撮像板上に結像させて得られた受光信号に基づいて、双方の拡散光源に設定された基準点との間をそれぞれ結ぶ２つの線分が成す偏角を測定する、地下坑内を掘進する掘進機の地中位置測定等に使用される偏角測定装置に関する。
【０００２】
【従来の技術】
地上または地下で建設作業を行う際に設計通りに工事が進んでいるかどうかを確認するために、基準となる基点と、その両側に所定の距離を置いて設定した計測点とをそれぞれ結ぶ二つの線分の成す角度（偏角）を測定することが必要になる場合が少なくない。例えば、屈曲した道路の工事を施工する場合には施工路面の屈曲部の角度を知ることが必要になる。この場合に、屈曲部の適所に基準となる基点を設定すると共に、これと距離を置いてその両側の路面施工区域にそれぞれ計測点を設定し、基点とその両側の計測点をそれぞれ結ぶ二つの線分の成す角度を測定する。
【０００３】
また、地中掘進機で緩やかに曲がった地下坑を掘削するには地中掘進機が計画路線に沿って正しく掘進しているかどうかを知るために、時々、地中掘進機の掘進位置を確認しなければならない。この場合にも地中掘進機に設けられた計測点とその後方の曲がった地下坑内にそれぞれ所定距離隔てて設けられた基点と計測点をそれぞれ結ぶ二つの線分の成す角度を測定する必要がある。なお、上記二つの線分の成す角度、即ち、偏角は内角または外角の何れを取っても良い。
【０００４】
建設作業において上記偏角を測定するには一般的に転鏡儀が用いられる。転鏡儀を用いて偏角を測定する時には、基点で望遠鏡を覗く作業者が他の作業者によって計測点に立てられた測量棒に焦点を合わせて、視野内の目盛りと測量棒に付された色目盛りとを合わせるという精密作業が必要となるので、熟練技術者等の限られた能力を有した人手を要するばかりでなく、上述のように精密で手間の掛かる作業なので一回の測定時間が長くなる。曲線経路の曲率半径が小さくなると、転鏡儀と測量棒の設置位置を頻繁に変更しなければならず、測量の作業効率が低下して作業時間が余計掛かってしまう。
【０００５】
さらに、望遠鏡を水平方向や垂直方向に回動させて焦点合わせをしなければならないので、回動機構に起因する僅かな機械的誤差が測定誤差に大きく影響してしまい、高い測定制度を得るのが難しい。特に、望遠鏡を水平方向や垂直方向に回動させるような振動等の偶発的外力が作用すると、上述の理由により大きな測定誤差が生じてしまう。
【０００６】
また、地中掘削において転鏡儀を用いた地中掘進機の地中位置を計測する作業を行う場合でも上述の事情は同様であり、しかも、地上における作業に較べてより計測作業が難しくなる。さらに、転鏡儀を用いた計測作業は作業者が坑内に入って作業することができる大口径管推進機には適用できるが、中口径管以下の口径の推進機には適用することができない。
【０００７】
一方、測角機能と測距機能とを具えて、坑内および掘進機に配置した標的を自動追尾することにより、掘進機の地中位置を自動測量するトータルステーションと称される自動測量装置が知られている。しかし、この装置は高度で複雑な測量機能を有しているため、高価で装置が大型化してしまい、工事費が高額になるばかりでなく、口径が小さい坑道掘削の測量には適用できない。さらに、曲線経路の曲率半径が小さな施工部分の掘進位置計測を行うには、坑内に複数台の自動測量装置を配置しなければならず、工事費が一層高額になってしまう。そこで、かかる問題認識の下に様々な技術開発が為されている。
【０００８】
例えば、特開平５−３４０１８６号公報には、見通しの利かないトンネル坑内に設定された後方基準点の前方に、測角機能を有するレーザー照準器を設置し、レーザー照準器から掘進機側に離れた位置に、レーザー照準器から照射されたレーザー光を屈折させて、その方向転角を測定できるウエッジプリズムを設けると共に、掘進機にレーザー光の標的を設けて、ウエッジプリズムの回転角に応じた偏角に関するデータと、レーザー照準器、ウエッジプリズムおよび掘進機に設けた標的の間の距離データとにより掘進機の地中位置を測定するようにした坑内測量方式の発明が開示されている。
【０００９】
この坑内測量方式では、収束度が高い光束であるレーザービームを掘進機に設けた標的の所定の位置を照射するように常にウエッジプリズムを回転制御しながら、検知したウエッジプリズムの回転角度に基づいて掘進機の計画線からのずれ量を計算機で算出している。このように、上記方式では掘進機の地中掘進位置を計測する際に、レーザー照準器から照射されたレーザー光が掘進機に設けた標的の所定の位置に的確に当たるように、ウエッジプリズムを精密に回転制御する回転制御機構が設けられている。このような回転制御機構の精密な制御を行っても、回転系の僅かな機械的誤差が大きな光学的誤差を生むことになり、レーザー照準器自体に水平または垂直方向の振動的外力が作用すると、光路が大きく振れるため、高い計測精度を得ることは実際上困難であった。
【００１０】
そこで、本出願人は特願平９−２９７２９５号（特開平１１−１３２７４６号公報）において、拡散光を照射する偏角計測用の光源と、照射された拡散光を集光した結像位置を検出する結像位置検出器とを光軸上に対を成して配置した偏角測定装置を坑内に複数配列して、それぞれに設けた基準点をそれぞれ結ぶ線分が成す偏角を計測することにより、レーザー光を標的の所定の位置に的確に当てるための追尾機構を不要にでき、駆動機構部の機械的誤差および偏角測定装置の取付け方向の誤差による偏角計測誤差、および装置が水平または垂直方向の外力を受けた時の偏角計測誤差の発生を無くし、掘進機の地中掘進位置を高精度に直ちに計測できるようにした偏角測定装置の発明を提案した。
【００１１】
図６は上述の従来例に係る偏角測定装置の内部構成を模式的に示す斜視図である。偏角測定装置１は集光レンズ４と、一対の発光ダイオード等の拡散光を発する拡散光源２１ａ，２１ｂと、集光レンズ４の光軸Ｃ上に集光レンズ４を挟んで対峙して設けられ、拡散光源２１ａ，２１ｂから射出された、それぞれ鉛直方向と水平方向に偏光面ｐｄ１，ｐｄ２を有した、即ち、Ｓ偏光の偏光拡散光束Ｌ１ ′，Ｌ２ ′を直角方向に反射可能な一対の偏光反射プリズム３ａ，３ｂと、前後方向に隣合う偏角測定装置１の拡散光源から射出された偏光拡散光束を受光したそれぞれの偏光拡散光束が偏光反射プリズム３ｂ，３ａをそれぞれ透過した後、集光レンズ４で集光され偏光反射プリズム３ａ，３ｂで直角方向に反射された拡散光束の結像位置にそれぞれ配置され、多数の固体電荷結合素子（ＣＣＤ）群で構成された撮像板５ａ，５ｂとから成っている。
【００１２】
拡散光源２１ａ，２１ｂはそれぞれ図示視鉛直方向および水平で光軸Ｃに垂直な方向の偏光面ｐｄ１，ｐｄ２を有した偏光拡散光を射出し、偏光面ｐｄ１，ｐｄ２に平行な反射面をそれぞれ有した偏光反射プリズム３ｂ，３ａは入射した偏光拡散光をそれぞれほぼ全量反射して光軸Ｃに沿って互いに反対方向（前後方向）に偏光拡散光束Ｌ１ ′，Ｌ２ ′として伝播させる。一方、基点における偏角測定装置１が前後方向に隣合う偏角測定装置１からそれぞれの光軸Ｃに沿って伝播した拡散光束Ｌ１ ′，Ｌ２ ′の中、少なくともその一部を受光すると、それぞれ偏光面ｐｄ１，ｐｄ２と垂直な偏光面を有した偏光拡散光束のみが偏光反射プリズム３ａ，３ｂの反射面を透過する。そして、集光レンズ４で集光された後、それぞれ偏光反射プリズム３ｂ，３ａに入射して、偏光面と平行な反射面で垂直に反射されて撮像板５ｂ，５ａ上に結像する。こうして、遠方に配置された光源の像が撮像板５ｂ，５ａ上に結像すると、結像位置にあるＣＣＤから受光量に比例した強度の受光信号が出力される。
【００１３】
なお、集光レンズ４の中心点と、これを挟んで対峙させた左右の偏光反射プリズム３ｂ，３ａの反射面と光軸Ｃとのそれぞれの交点との間の距離は、それらの交点と拡散光源２１ｂ，２１ａの射出口との距離に一致させてある。また、集光レンズ４の中心点と偏光反射プリズム３ｂ，３ａの反射面と光軸Ｃとの交点との間の距離と、該交点から撮像板５ｂ，５ａまでの距離との和は集光レンズ４の焦点距離にほぼ等しくなるように設定されている。そして、本実施例では集光レンズ４の中心点を偏角測定装置１の基準点に設定している。このように設定することにより、拡散光源２１ａ，２１ｂから射出された偏光拡散光束Ｌ１ ′，Ｌ２ ′は恰も基準点から射出された偏光拡散光束のように光軸Ｃに沿って前後方向に伝播して行く。また、遠距離から到達した拡散光は撮像板５ａ，５ｂ上に明瞭な像を結ぶ。
【００１４】
図７は地山を掘削して推進する掘進機の地中掘進位置を上述の偏角測定装置１で計測する計測方法を説明するための説明図である。ここでは、掘進機７が発進立坑１０から発進して、水平方向に湾曲する曲線経路に沿って推進する曲線施工する場合について説明する。この例では坑内に５台の偏角測定装置１１ 〜１５ が離間配置されると共に通信ラインを介してそれぞれ位置演算装置８に接続されている。そして、位置演算装置８にはそれぞれの偏角測定装置１１ 〜１５ の地中位置座標がグラフと表で表示される表示装置９が接続されている。第５の偏角測定装置１５ は掘進機７に取り付けられ、その後方の地下坑１１内にそれぞれほぼ所定の間隔を隔てて第２〜第４の偏角測定装置１２ 〜１４ が配置され、発進立坑１０内に第１の偏角測定装置１１ が配置される。偏角測定装置１ｉ （ｉ＝１〜５）にはそれぞれ図示しないレーザー距離測定器が取り付けられていて、このレーザー距離測定器で測定された隣合う偏角測定装置１ｉ＋１ との間の距離データもそれぞれ位置演算装置８に転送されていて、それらに基づいて各偏角測定装置１ｉ の地中位置座標が測定されている。
【００１５】
偏角測定装置１ｉ にはそれぞれ２つずつの拡散光源２１ａ，２１ｂが設けられており、中間の３つの偏角測定装置１２ 〜１４ では２つ拡散光源２１ａ，２１ｂが共に点灯されるが、両端に位置する偏角測定装置１１ ，１５ ではその中の隣合う偏角測定装置１が存在する側の拡散光源２１（ａ，ｂ）のみが点灯される。例えば、真ん中の偏角測定装置１３ に注目すると、偏角測定装置１３ の撮像板５ｂ，５ａは両側の偏角測定装置１２ ，１４ から射出された偏光拡散光束ＬＡ ，ＬＢ を受光し、それらの結像位置にあるＣＣＤから位置演算装置８に受光信号が出力される。位置演算装置８は上述した受光信号に基づいて偏角測定装置１３ の基準点と偏角測定装置１２ ，１４ の基準点とを結ぶ線分ｍＡ ，ｍＢ が成す偏角Φを演算すると共に、別途それぞれレーザー距離測定器で測定された偏角測定装置１２ ，１４ との間の距離、即ち、線分ｍＡ ，ｍＢ の長さが演算され、両者の演算結果に従って偏角測定装置１４ の基準点の地中位置座標が決定される。同様にして、他の偏角測定装置１ｉ （ｉ≠４）の基準点の地中位置座標が決定される。
【００１６】
【発明が解決しようとする課題】
このようにして、それぞれ隣合う他の偏角測定装置１ｉ の拡散光源２１ａ，２１ｂから射出された偏光拡散光束ＬＡ ，ＬＢ を撮像板５ｂ，５ａが受光することにより、水平方向に湾曲する曲線経路に沿って推進する掘進機７の地中位置座標を多くの人手を煩わせたり、追尾機構等を具えた複雑で高価な装置を用いることなく、小口径の坑道内であっても容易に測定することができる。
【００１７】
上記従来技術に係る偏角測定装置１では拡散光源２１ａ，２１ｂからの拡散光束ＬＡ ，ＬＢ の結像位置を検出することにより、照射光を追尾するための機構を不要にしているが、拡散光束ＬＡ ，ＬＢ の強度は距離の二乗に比例して減少するため、隣合う偏角測定装置１ｉ−１ ，１ｉ＋１ との間の距離をあまり大きくすることができず、従って、長い坑道内の掘進機７の地中位置の測定を行うには多数の偏角測定装置１を坑道内に配置しなければならないという問題点があった。特に、掘進機７が推進する水平坑道の曲線経路の曲率が大きい時は拡散角が大きい拡散光束ＬＡ ，ＬＢ を射出する拡散光源２１ａ，２１ｂを具えた偏角測定装置１を用いなければならず、このような場合には隣合う偏角測定装置１ｉ−１ ，１ｉ＋１ との間の距離が長くなると、拡散光束ＬＡ ，ＬＢ の強度の低下が著しく、測定精度の低下を招いていた。
【００１８】
本発明は従来技術におけるかかる課題を解決すべく為されたものであり、一平面に平行に沿って湾曲する曲線経路内の偏角を測定するのに、拡散光源からの距離が長くても著しい受光光量の低下を来さず、拡散光束のエネルギーを有効に利用できる偏角測定装置を提供することを目的とする。
【００１９】
【課題を解決するための手段】
本発明は上記課題を解決するために、集光レンズの光軸の前後方向の所定の位置にそれぞれ配置された双方の拡散光源は、基点と双方の拡散光源に設定された基準点との間をそれぞれ結ぶ２つの線分を含む１平面方向に他の方向より広く拡散する強度方向異方性を有した拡散光束を射出するようにしたものであり、好ましくは、偏角測定装置は光軸の前後方向に向けてそれぞれ拡散光束を射出する２つの拡散光源を具えており、集光レンズは光軸の前後方向の所定の位置にそれぞれ配置された同形の偏角測定装置の拡散光源から射出された拡散光束の少なくとも一部を集光して撮像板上に結像させるようにし、集光レンズを挟んで一対の偏光反射プリズムを集光レンズの光軸上に対峙させ、２つの拡散光源は強度方向異方性を有して、それぞれ光軸に垂直な方向に射出された偏光拡散光束を、偏光反射プリズムの反射面で反射させて光軸の前後方向に向けてそれぞれ射出すると共に、光軸の前後方向の所定の位置に配置された拡散光源から射出されて一方の偏光反射プリズムに入射した偏光拡散光束はその反射面を透過して集光レンズで集光され、他方の偏光反射プリズムの反射面で反射されて撮像板上に結像されるように構成したものである。また、一方の拡散光源と一方の偏光反射プリズムとの間にλ／２波長板を配置し、該λ／２波長板は該λ／２波長板を透過する拡散光源からの偏光拡散光束の強度方向異方性を維持しながら、その偏光面のみを９０°回転させるようにしても良い。
【００２０】
【発明の実施の形態】
以下、図面を参照して本発明の実施例を詳細に説明する。図３は本実施例に係る光源から射出される拡散光束の強度方向異方性を示す模式図である。本実施例において用いられる拡散光源２には、射出される拡散光束Ｌの方向強度分布が方向異方性を有した半導体レーザー発光素子が用いられる。同図に示すように、拡散光源２から射出される拡散光束Ｌの等強度分布曲線は長軸方向の大きな拡散角ｗｌ と短軸方向の小さな拡散角ｗｓ とを有した長楕円形を成している。そして、拡散光束Ｌの偏光面は長楕円形の長軸方向に平行な偏光面ｐｄまたは短軸方向に平行な偏光面ｐｄ′となっている。
【００２１】
このように、拡散光源２として２軸方向に大きな強度方向異方性を有したものを用いることにより、拡散光束Ｌは短軸方向にはあまり拡散せず、長軸方向には広く拡散する拡散特性を有し、従って、受光距離に対する強度減衰特性は距離の二乗ではなく、殆ど距離に比例して減衰する特性を有したものとなる。つまり、本実施例では半導体レーザー発光素子から射出される拡散光束Ｌが２軸方向に大きな強度方向異方性を有しているのを利用して、拡散光束Ｌが受光距離に対して緩やかな強度減衰特性を有した拡散光源２とすることができるから、測定精度の低下を来すことなく、配置される偏角測定装置相互の間隔を相対的に大きく取ることができる。
【００２２】
図１は本発明の第１の実施例に係る偏角測定装置の内部構成を模式的に示す斜視図である。同図において、２ａ，２ｂは光軸Ｃに垂直な方向にそれぞれ所定距離離間し、光軸Ｃの回りに９０°異なる取付け角を有して配置された半導体レーザー発光素子から成る拡散光源、６は拡散光源２ａの拡散光束Ｌ１ の射出口に対向する位置に配置されたλ／２波長板である。なお、従来例と同一または同一と見做せる個所には同一の符号を付し、その重複する説明を省略する。拡散光源２ａ，２ｂの偏光面は水平面内でそれぞれ光軸Ｃに平行および垂直になるように、そして、拡散光束Ｌ１ ，Ｌ２ の強度方向異方性はその長軸方向が共に水平面と平行になるように設定されている。また、λ／２波長板６はその主断面が拡散光源２ａの拡散光束Ｌ１ の偏光面に対して４５°傾いた向きとなるように配置される。
【００２３】
拡散光源２ａから射出された拡散光束Ｌ１ は上述のように、強度方向異方性はその長軸方向が水平面と平行になるように、偏光面は水平面内で光軸Ｃに平行になるように設定されているが、λ／２波長板６に入射して透過する過程で、周知のように偏光面が９０°回転する。従って、拡散光束Ｌ１ が偏光反射プリズム３ａに入射する際には、偏光面は同図で鉛直な方向、即ち、Ｓ偏光の偏光面ｐｄ１を有し、強度方向異方性はその長軸方向が水平面と平行な状態となっている。このように、偏光反射プリズム３ａに入射した拡散光束Ｌ１ の偏光面ｐｄ１は鉛直方向になっているから、偏光反射プリズム３ａの反射面に入射した拡散光束Ｌ１ はほぼ全量が９０°反射され、光軸Ｃに沿って伝播する。拡散光束Ｌ１ の強度方向異方性はその長軸方向が水平面と平行な方向になっているから、鉛直な方向にはあまり拡散せず、ほぼ水平な方向には広く拡散して伝播し、その強度はほぼ距離に比例して減衰する。
【００２４】
このようにして、同図で光軸Ｃに沿って、その左側に隣接する同形の偏角測定装置１から射出された拡散光束Ｌ１ が水平方向に拡散しながら当該偏角測定装置１に向かって伝播する。拡散光束Ｌ１ は水平方向に拡散しているから、左側に隣接する偏角測定装置１が光軸Ｃから少し離れた位置にあってもさ程減衰することなく到達して、その偏光反射プリズム３ｂに入射する。この入射した拡散光束Ｌ１ の偏光面ｐｄ１は鉛直方向になっているから、水平面に対して４５°傾いた向きの反射面で反射されることなく、殆ど全量が透過し、集光レンズ４で集光された後、偏光反射プリズム３ａに入射する。偏光反射プリズム３ａの反射面は鉛直方向を向いているから、拡散光束Ｌ１ は集光しつつ、この反射面でほぼ全量が９０°反射されて撮像板５ａ上に結像する。結像位置にあるＣＣＤから出力された受光信号は従来例で述べた位置演算装置８に転送され、そこで拡散光束Ｌ１ を発した偏角測定装置１と当該偏角測定装置１の基準点とを結ぶ線分ｍＡ と光軸Ｃとが成すずれ角が演算される。
【００２５】
一方、同図で光軸Ｃに沿って、その右側に隣接する同形の偏角測定装置１の拡散光源２ｂから射出された拡散光束Ｌ２ は上述のように、強度方向異方性はその長軸方向が水平面と平行に、偏光面は水平面内で光軸Ｃに垂直になるようにそれぞれ設定されているから、拡散光束Ｌ２ は偏光反射プリズム３ｂに入射して、水平面に対して４５°傾いた向きの反射面でほぼ全量が９０°反射され、光軸Ｃに沿って左側に水平な方向に広く拡散して伝播する。右側に隣接する同形の偏角測定装置１から伝播した拡散光束Ｌ２ は水平方向に拡散しているから、その偏角測定装置１が光軸Ｃから少し離れた位置にあってもさ程減衰することなく到達して、偏光反射プリズム３ａに入射する。偏光反射プリズム３ａの反射面は鉛直方向を向いているから、水平方向の偏光面ｐｄ２を有した拡散光束Ｌ２ はこの反射面で反射されることなく、殆ど全量が透過し、集光レンズ４で集光された後、偏光反射プリズム３ｂに入射する。
【００２６】
偏光反射プリズム３ｂの反射面は水平面に対して４５°傾いた向きに設定されているから、拡散光束Ｌ２ は集光しつつ、この反射面でほぼ全量が９０°反射されて撮像板５ｂ上に結像する。結像位置にあるＣＣＤから出力された受光信号は上述のように、位置演算装置８に転送され、そこで拡散光束Ｌ２ を発した偏角測定装置１と当該偏角測定装置１の基準点とを結ぶ線分ｍＢ と光軸Ｃとが成すずれ角が演算される。そして、光軸Ｃの左側に隣接する偏角測定装置１と当該偏角測定装置１の基準点とを結ぶ線分ｍＡ と光軸Ｃとが成すずれ角と、光軸Ｃの右側に隣接する偏角測定装置１と当該偏角測定装置１の基準点とを結ぶ線分ｍＢ と光軸Ｃとが成すずれ角とから線分ｍＡ と線分ｍＢ とが成す偏角Φが演算される。こうして、光軸Ｃの絶対的な向きとは関わりなく偏角Φを求めることができる。
【００２７】
次に、図示しないレーザー距離測定器で測定された光軸Ｃの右側に隣接する偏角測定装置１と当該偏角測定装置１の基準点とを結ぶ線分ｍＢ の長さを参照して、光軸Ｃの右側に隣接する偏角測定装置１の基準点の当該偏角測定装置１の基準点に対する相対位置が決定される。以下、同様にして隣接する偏角測定装置１の基準点の相対位置が次々に決められるから、最初に予め座標位置が確定している、例えば、発進立抗内に設置された偏角測定装置１の基準点に対する地下坑内の先端部に位置する掘進機の基準点の絶対位置が決定される。
【００２８】
このように、本実施例では拡散光源２ａ，２ｂとして、強度方向異方性を有し、その長軸方向と偏光面が平行となるような半導体レーザー発光素子を用い、構造を簡素に、かつ、小型化するために、λ／２波長板６を用いて一方の拡散光源２ａから射出された拡散光束Ｌ１ のみの偏光面を９０°回転させることにより、拡散光源２ａ，２ｂから射出された拡散光束Ｌ１ ，Ｌ２ を共にそれぞれ偏光反射プリズム３ａ，３ｂの反射面でほぼ全量を９０°反射させ、かつ、偏光面は鉛直方向と水平方向とにそれぞれ異なる向きを有しながら、共に水平方向に広く拡散して伝播するようにでき、しかも、隣接する偏角測定装置１から受光した拡散光束Ｌ１ ，Ｌ２ が最初に入射する偏光反射プリズム３ｂ，３ａの反射面を共に透過させて集光レンズ４に導き、集光させるようにできる。
【００２９】
図４および図５はこの辺の事情を説明するための図であり、図４はλ／２波長板６を用いなかった場合の偏角測定装置の内部構成を模式的に示す斜視図、図５は地下坑道内に配置されたｋ番目の偏角測定装置の受光状態を示す模式図である。光源から射出された照射光を光軸Ｃに沿って伝播させると共に、他の偏角測定装置１から照射された照射光の少なくとも一部を受光することにより、光軸Ｃの延長線の近傍に配置された両側に隣合う偏角測定装置１の基準点との間を結ぶ２つの線分が成す偏角Φを精度良く計測するには、光源として偏光光源２ａ，２ｂを用い、光軸Ｃ上に集光レンズ４を挟んで一対の偏光反射プリズム３ａ，３ｂを対峙させ、偏光光源２ａと撮像板５ａおよび偏光光源２ｂと撮像板５ｂをそれぞれ光軸Ｃと直交する９０°取付け角度が異なる方向にそれぞれ偏光反射プリズム３ａ，３ｂを挟んで対峙させ、偏光反射プリズム３ａ，３ｂの反射面がそれぞれ偏光光源２ａ，２ｂから射出された拡散光束Ｌ１ ″，Ｌ２ の偏光面と平行になるように配置した構成が必然的な構成となる。
【００３０】
この構成を具体的に図示したのが図４であって、この場合は、光軸Ｃに沿って伝播する拡散光束Ｌ１ ″，Ｌ２ は同図に示すように、偏光反射プリズム３ｂの反射面で反射される拡散光束Ｌ２ は水平方向に広く拡散する光束となるものの、偏光反射プリズム３ａの反射面で反射される拡散光束Ｌ１ ″は鉛直方向に広く拡散する光束となる。従って、このような偏角測定装置１を地下坑内に間隔を隔てて配置して、地下坑内の先端部に位置する掘進機の位置測定を行おうとすると、図５に示すように、ｋ番目の偏角測定装置１ｋ の前方に隣合う偏角測定装置１ｋ＋１ から偏角測定装置１ｋ に向けて射出された拡散光束Ｌｋ＋１ は水平方向に広く拡散する光束となっているため、偏角測定装置１ｋ に容易に受光されるが、偏角測定装置１ｋ の後方に隣合う偏角測定装置１ｋ−１ から偏角測定装置１ｋ に向けて射出された拡散光束Ｌｋ−１ は鉛直方向に広く拡散する光束となっているため、偏角測定装置１ｋ には殆ど届かず、受光され難い。
【００３１】
このように、一方向に射出される拡散光束Ｌ１ ″が鉛直方向に広く拡散する光束とした複数の偏角測定装置１を地下坑内に間隔を隔てて配置して、地下坑内の先端部に位置する掘進機の位置測定を行おうとすると、隣合う偏角測定装置１が光軸Ｃ上から僅かずれた位置に配置されただけでも、その偏角測定装置１から射出された拡散光束（例えば、図５の拡散光束Ｌｋ−１ ）を受光することができず、従って、掘進機の位置測定を行うことができなくなってしまう。
【００３２】
そこで、本実施例では一方の偏光光源２ａの取付け向きを９０°回転させて、拡散光束Ｌ１ が水平方向に広く拡散する光束となるようにすると共に、その偏光面をλ／２波長板６で９０°回転させて鉛直方向に向くようにし、偏光反射プリズム３ａの反射面に平行に入射してほぼ全量が９０°反射されるようにしたものである。こうして、偏角測定装置１から射出された拡散光束Ｌ１ ，Ｌ２ を共に水平方向に他の方向より広く拡散する光束とすることができ、水平方向に湾曲する曲線経路に沿って推進する曲線施工工事における掘進機の位置測定を行う場合に、拡散光束Ｌ１ ，Ｌ２ のエネルギーを有効に利用して、隣合う偏角測定装置１が光軸Ｃ上からややずれた位置に配置されていても容易に受光することができるから、少ない数の偏角測定装置１を地下坑内に配置するだけで精度の良い掘進機の位置測定を行うことができる。
【００３３】
本実施例では射出された拡散光束Ｌ１ ，Ｌ２ の拡散方向と偏光面とが同じ向きの半導体レーザー発光素子から成る拡散光源２ａ，２ｂを用いたので、その一方の拡散光源２ａの前方にλ／２波長板６を配置して、偏光面を９０°回転させなければならなかったが、一方の拡散光源２ａに、拡散方向と偏光面の向きとが９０°異なる半導体レーザー発光素子を用いれば上記λ／２波長板６を配置する必要はない。図２は本発明の第２の実施例に係る偏角測定装置の内部構成を模式的に示す斜視図であり、偏角測定装置１の構成は従来例のものと殆ど変わらない。ただし、一方の拡散光源２ａは上述のように、拡散方向と偏光面の向きとが９０°異なる半導体レーザー発光素子が用いられている。これにより、一対の偏光反射プリズム３ａ，３ｂから第１の実施例と同様の、光軸Ｃに沿って前後方向に、水平な方向に他の方向よりも広く拡散する拡散光束Ｌ１ ，Ｌ２ を伝播させることができる。なお、鉛直方向に湾曲する曲線経路内の偏角を測定する場合は、勿論、拡散光源から射出される拡散光束の広がり方向を鉛直方向に他の方向よりも広く拡散するように設定すれば良い。
【００３４】
【発明の効果】
以上説明したように請求項１記載の発明によれば、光軸の前後方向の所定の位置にそれぞれ配置された双方の拡散光源は、それらに設定された基準点と基点との間をそれぞれ結ぶ２つの線分を含む１平面方向に他の方向より広く拡散する強度方向異方性を有した拡散光束を射出するようにしたので、一平面に平行に沿って湾曲する曲線経路内の偏角を測定するのに、拡散光源からの距離が長くても著しい受光光量の低下を来さず、拡散光束のエネルギーを有効に利用することができる。
請求項２記載の発明によれば、偏角測定装置は光軸の前後方向に向けてそれぞれ拡散光束を射出する２つの拡散光源を具えており、集光レンズは光軸の前後方向の所定の位置にそれぞれ配置された同形の偏角測定装置の拡散光源から射出された拡散光束の少なくとも一部を集光して撮像板上に結像させるようにしたので、曲線経路に沿った複数箇所での偏角を測定する場合に、当該測定箇所に同形の偏角測定装置をそれぞれ配置するだけでそれぞれの偏角を測定することができるから、偏角測定作業を極めて容易に行うことができる。
【００３５】
請求項３記載の発明によれば、２つの拡散光源は強度方向異方性を有して、それぞれ集光レンズの光軸に垂直な方向に射出された偏光拡散光束を、偏光反射プリズムの反射面で反射させて光軸の前後方向に向けてそれぞれ射出すると共に、光軸の前後方向の所定の位置に配置された拡散光源から射出されて一方の偏光反射プリズムに入射した偏光拡散光束はその反射面を透過して集光レンズで集光され、他方の偏光反射プリズムの反射面で反射されて撮像板上に結像されるように構成したので、１枚の集光レンズだけで両方向から伝播した偏光拡散光束を集光して撮像板上に結像させることができると共に、光軸に対して集光レンズが設けられた基点から前後方向に隣合う他の偏角測定装置の基点を見込むずれ角の偏差として、偏角を正確に測定することができる。
【００３６】
請求項４記載の発明によれば、一方の拡散光源と一方の偏光反射プリズムとの間に配置したλ／２波長板はそれを透過する拡散光源からの偏光拡散光束の強度方向異方性を維持しながら、その拡散光源から光軸に垂直な方向に射出された偏光拡散光束の偏光面のみを９０°回転させるようにしたので、偏光拡散光束の拡散方向と偏光面の方向が共通の２つの拡散光源を用いて、１平面方向にのみほぼ拡散する強度方向異方性を有した拡散光束をそれぞれ射出するようにできる。
【００３７】
請求項５記載の発明によれば、半導体レーザー発光素子を拡散光源として用いたので、比較的汎用性の高い電子部品で拡散光源を構成できるから、主要部品の入手が容易で、装置の精度バラ付きを低減できる。
【図面の簡単な説明】
【図１】本発明の第１の実施例に係る偏角測定装置の内部構成を模式的に示す斜視図
【図２】本発明の第２の実施例に係る偏角測定装置の内部構成を模式的に示す斜視図
【図３】本実施例に係る光源から射出される拡散光束の強度方向異方性を示す模式図
【図４】本発明の第１の実施例で、λ／２波長板を用いなかった場合の偏角測定装置の内部構成を模式的に示す斜視図
【図５】同じく、地下坑道内に配置されたｋ番目の偏角測定装置の受光状態を示す模式図
【図６】従来例に係る偏角測定装置の内部構成を模式的に示す斜視図
【図７】従来例に係る偏角測定装置で掘進機の地中掘進位置を計測する計測方法を説明するための説明図
【符号の説明】
１ 偏角測定装置
２，２１（ａ，ｂ） 拡散光源
３（ａ，ｂ） 偏光反射プリズム
４ 集光レンズ
５（ａ，ｂ） 撮像板
６ λ／２波長板
７ 掘進機
８ 位置演算装置
９ 表示装置
１１ 地下坑
Ｌ１ ，Ｌ２ 拡散光束
ｐｄ１，ｐｄ２ 偏光面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to both diffused light sources based on a received light signal obtained by imaging a diffused light beam emitted along the optical axis from a diffused light source disposed in the vicinity of the optical axis in the front-rear direction. The present invention relates to a declination measuring device used for measuring the declination angle formed by two line segments each connecting to a reference point set to 1 and used for measuring the underground position of an excavating machine that excavates in an underground mine.
[0002]
[Prior art]
In order to confirm whether the construction is proceeding as designed when performing construction work on the ground or underground, two reference points are connected to the measurement points set at a predetermined distance on both sides. In many cases, it is necessary to measure the angle (declination) formed by a line segment. For example, when constructing a bent road, it is necessary to know the angle of the bent portion of the construction road surface. In this case, a reference base point is set at an appropriate position of the bent part, and a measurement point is set in each road surface construction area at a distance from the reference point, and the base point and the measurement points on both sides thereof are respectively connected. Measure the angle formed by the line segment.
[0003]
Also, in order to dig a gently bent underground mine with an underground excavator, sometimes check the excavation position of the underground excavator to know whether the underground excavator is excavating correctly along the planned route Must. In this case as well, it is necessary to measure the angle formed by two line segments connecting the measurement point provided in the underground excavation machine and the base point provided at a predetermined distance in the bent underground mine behind it and the measurement point, respectively. is there. Note that the angle formed by the two line segments, that is, the declination, may take either an inner angle or an outer angle.
[0004]
A mirror is generally used to measure the declination in construction work. When measuring the declination using a mirror, the operator looking into the telescope at the base point focuses on the surveying bar set up at the measurement point by another operator, and is attached to the scale and surveying bar in the field of view. It requires precision work to match the color scale, so it requires not only manual work with limited skills such as skilled engineers, but also the precise and time-consuming work as described above, so it takes one measurement time. Becomes longer. If the radius of curvature of the curved path is reduced, the installation position of the mirror and the surveying rod must be changed frequently, which reduces the work efficiency of surveying and increases the work time.
[0005]
Furthermore, since the telescope must be rotated in the horizontal and vertical directions for focusing, a slight mechanical error caused by the rotation mechanism greatly affects the measurement error, and a high measurement system is obtained. Is difficult. In particular, if an accidental external force such as vibration that rotates the telescope in the horizontal direction or the vertical direction acts, a large measurement error occurs due to the above-described reason.
[0006]
In addition, the above-mentioned circumstances are the same even when performing the work of measuring the underground position of the underground excavator using a mirror in underground excavation, and the measurement work becomes more difficult than the work on the ground. . Furthermore, the measurement work using the mirror can be applied to a large-diameter pipe propulsion device that allows an operator to enter the mine and work, but cannot be applied to a propulsion machine having a caliber smaller than a medium-diameter pipe. .
[0007]
On the other hand, an automatic surveying device called a total station that has an angle measurement function and a distance measurement function and automatically surveys the underground position of the excavator by automatically tracking the targets placed in the mine and the excavator is known. ing. However, since this apparatus has an advanced and complicated surveying function, it is expensive and increases the size of the apparatus, which not only increases the construction cost but also cannot be applied to surveying for excavation of a mine with a small diameter. Furthermore, in order to measure the excavation position of a construction portion where the curvature radius of the curved path is small, it is necessary to arrange a plurality of automatic surveying devices in the mine, which further increases the construction cost. Therefore, various technological developments have been made based on such problem recognition.
[0008]
For example, in Japanese Patent Laid-Open No. 5-340186, a laser sighting device having an angle measuring function is installed in front of a rear reference point set in a tunnel mine where visibility is not good, and the laser sighting device is moved away from the laser sighting device to the excavator side. A wedge prism that can refract the laser light emitted from the laser sighting device and measure the direction turning angle is provided at the position, and a laser beam target is provided on the excavator, according to the rotation angle of the wedge prism. An invention of an underground surveying system is disclosed in which the underground position of an excavator is measured based on data related to declination and data on the distance between a laser sighting device, a wedge prism and a target provided in the excavator.
[0009]
In this underground surveying method, based on the detected rotation angle of the wedge prism, while constantly controlling the rotation of the wedge prism so that the laser beam, which is a light beam with high convergence, is irradiated to a predetermined position of the target provided in the excavator The amount of deviation from the planned line of the excavator is calculated by a computer. As described above, in the above method, when measuring the underground excavation position of the excavator, the wedge prism is precisely adjusted so that the laser beam emitted from the laser sighting device accurately hits a predetermined position of the target provided in the excavator. Is provided with a rotation control mechanism for controlling rotation. Even if precise control of such a rotation control mechanism is performed, a slight mechanical error of the rotating system will cause a large optical error, and if a horizontal or vertical vibration external force acts on the laser sighting device itself. Since the optical path fluctuates greatly, it is practically difficult to obtain high measurement accuracy.
[0010]
In view of this, the present applicant in Japanese Patent Application No. Hei 9-297295 (Japanese Patent Laid-Open No. 11-132746) has a light source for declination measurement that irradiates diffused light, and an imaging position where the irradiated diffused light is condensed. A plurality of declination measuring devices arranged in pairs on the optical axis to detect the imaging position detector are arranged in the pit, and the declination formed by the line segments respectively connecting the reference points provided for each is measured. This eliminates the need for a tracking mechanism for accurately irradiating the laser beam to a predetermined position of the target, and the deviation angle measurement error due to the mechanical error of the drive mechanism and the error in the mounting direction of the deviation angle measurement device, and the device An invention of a declination measuring device has been proposed which eliminates the occurrence of declination measurement errors when receiving external force in the horizontal or vertical direction, and can immediately measure the underground excavation position of the excavator with high accuracy.
[0011]
FIG. 6 is a perspective view schematically showing an internal configuration of the deflection angle measuring apparatus according to the above-described conventional example. The declination measuring device 1 is provided to confront the condenser lens 4, diffused light sources 21 a and 21 b that emit diffused light such as a pair of light emitting diodes, and the condenser lens 4 on the optical axis C of the condenser lens 4. The polarized light fluxes L emitted from the diffusion light sources 21a and 21b and having polarization planes pd1 and pd2 in the vertical direction and the horizontal direction, respectively, that is, S-polarized polarized light beams L 1 ', L 2 And a pair of polarized light reflecting prisms 3a and 3b capable of reflecting the light beam in a right angle direction, and each polarized light diffusing light beam received from the diffused light source emitted from the diffusion light source of the deflection angle measuring apparatus 1 adjacent in the front-rear direction is a polarized light reflecting prism. A plurality of solid state charge coupled devices (CCDs) are respectively disposed at the imaging positions of diffused light beams that have been transmitted through 3b and 3a and then condensed by the condenser lens 4 and reflected by the polarization reflecting prisms 3a and 3b at right angles. It consists of imaging plates 5a and 5b configured in groups.
[0012]
The diffused light sources 21a and 21b respectively emit polarized diffused light having polarization planes pd1 and pd2 in the vertical direction as viewed in the drawing and in the direction perpendicular to the optical axis C and have reflection surfaces parallel to the polarization planes pd1 and pd2, respectively. The polarized light reflecting prisms 3b and 3a reflect almost all of the incident polarized diffused light, and are polarized diffused light flux L in the opposite direction (front-rear direction) along the optical axis C. 1 ', L 2 Propagate as'. On the other hand, the diffused light beam L propagated along the optical axis C from the deflection angle measurement device 1 adjacent in the front-rear direction by the deflection angle measurement device 1 at the base point. 1 ', L 2 When at least part of the light is received, only the polarized diffused light beams having the polarization planes perpendicular to the polarization planes pd1 and pd2 are transmitted through the reflection surfaces of the polarization reflection prisms 3a and 3b. Then, after being condensed by the condenser lens 4, the light is incident on the polarization reflecting prisms 3 b and 3 a, and is reflected vertically by a reflecting surface parallel to the polarizing surface to form an image on the imaging plates 5 b and 5 a. Thus, when an image of a light source arranged far away is formed on the imaging plates 5b and 5a, a light reception signal having an intensity proportional to the amount of light received is output from the CCD at the image formation position.
[0013]
It should be noted that the distance between the center point of the condenser lens 4 and the intersections of the reflection surfaces of the left and right polarization reflecting prisms 3b, 3a facing each other and the optical axis C is the distance between these intersection points and the diffusion. The distance between the light sources 21b and 21a and the exit is matched. Further, the sum of the distance between the center point of the condenser lens 4 and the intersection of the reflection surface of the polarizing reflection prisms 3b and 3a and the optical axis C and the distance from the intersection to the imaging plates 5b and 5a is a condensing light. It is set to be approximately equal to the focal length of the lens 4. In this embodiment, the central point of the condenser lens 4 is set as the reference point of the declination measuring device 1. By setting in this way, the polarized diffused light beam L emitted from the diffused light sources 21a and 21b. 1 ', L 2 ′ Propagates in the front-rear direction along the optical axis C like a polarized diffused light beam emitted from the reference point. Further, the diffused light reaching from a long distance forms a clear image on the imaging plates 5a and 5b.
[0014]
FIG. 7 is an explanatory diagram for explaining a measurement method for measuring the underground excavation position of the excavator for excavating and propelling the natural ground with the above-described declination measuring device 1. Here, a case will be described in which the excavator 7 starts from the start shaft 10 and performs a curve construction that propels along a curved path that curves in the horizontal direction. In this example, there are five declination measuring devices 1 in the mine. 1 ~ 1 5 Are spaced apart from each other and connected to the position calculation device 8 via a communication line. The position calculation device 8 includes each declination measuring device 1. 1 ~ 1 5 Is connected to a display device 9 for displaying the ground position coordinates in a graph and a table. Fifth declination measuring device 1 5 Is attached to the excavator 7, and the second to fourth declination measuring devices 1 are respectively provided in the underground mine 11 behind the excavator 7 with a predetermined interval therebetween. 2 ~ 1 4 Is arranged, and the first declination measuring device 1 is provided in the start shaft 10. 1 Is placed. Deviation measuring device 1 i A laser distance measuring device (not shown) is attached to each of (i = 1 to 5), and the adjacent declination measuring device 1 measured with this laser distance measuring device. i + 1 Is also transferred to the position calculation device 8 respectively, and based on them, each declination measuring device 1 i The underground position coordinates of are measured.
[0015]
Deviation measuring device 1 i Each has two diffused light sources 21a and 21b, and three intermediate deflection angle measuring devices 1 are provided. 2 ~ 1 4 Then, the two diffused light sources 21a and 21b are both turned on, but the declination measuring device 1 located at both ends. 1 , 1 5 Then, only the diffused light source 21 (a, b) on the side where the adjacent declination measuring device 1 exists is turned on. For example, middle deviation angle measuring device 1 3 Paying attention to the declination measuring device 3 The imaging plates 5b, 5a are declination measuring devices 1 on both sides. 2 , 1 4 Polarized diffused light flux L emitted from A , L B Are received, and a light reception signal is output from the CCD at the image forming position to the position calculation device 8. The position calculation device 8 is based on the light reception signal described above, and the deflection angle measuring device 1 3 Reference point and declination measuring device 1 2 , 1 4 Line segment connecting the reference point of A , M B Is a declination measuring device 1 that calculates the declination Φ formed by and separately measured by a laser distance measuring device. 2 , 1 4 Distance between and the line segment m A , M B Is calculated, and the declination measuring device 1 according to the calculation result of both 4 The ground position coordinates of the reference point are determined. Similarly, another declination measuring device 1 i The ground position coordinates of the reference point (i ≠ 4) are determined.
[0016]
[Problems to be solved by the invention]
In this way, other declination measuring devices 1 adjacent to each other. i Polarized diffused light beams L emitted from the diffusion light sources 21a and 21b A , L B When the imaging plates 5b and 5a receive the light, the underground position coordinates of the excavator 7 propelled along a curved path that curves in the horizontal direction are troubled by many people, complicated and expensive with a tracking mechanism or the like. Measurement can be easily performed even in a small-diameter tunnel without using a simple device.
[0017]
In the deflection angle measuring apparatus 1 according to the above-described prior art, the diffused light beam L from the diffused light sources 21a and 21b. A , L B By detecting the image forming position, the mechanism for tracking the irradiation light is made unnecessary. A , L B Is reduced in proportion to the square of the distance. i-1 , 1 i + 1 Therefore, a large number of declination measuring devices 1 must be arranged in the tunnel to measure the underground position of the excavator 7 in the long tunnel. There was a problem. In particular, when the curvature of the curved path of the horizontal tunnel propelled by the excavator 7 is large, the diffused light beam L having a large diffusion angle. A , L B The declination measuring device 1 including the diffused light sources 21a and 21b that emit the light must be used. In such a case, the adjacent declination measuring device 1 is used. i-1 , 1 i + 1 When the distance between is increased, the diffused light beam L A , L B As a result, the strength of the sample significantly decreased, resulting in a decrease in measurement accuracy.
[0018]
The present invention has been made to solve such a problem in the prior art, and it is remarkable even when the distance from the diffused light source is long to measure the declination in a curved path that is curved parallel to one plane. It is an object of the present invention to provide a declination measuring device that can effectively use the energy of a diffused light beam without reducing the amount of received light.
[0019]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides that both diffused light sources respectively disposed at predetermined positions in the front-rear direction of the optical axis of the condenser lens are between a base point and a reference point set for both diffused light sources. The diffuse angle measuring device emits a diffused light beam having intensity direction anisotropy that diffuses more widely than the other directions in one plane direction including two line segments that connect each other. Two diffused light sources that emit diffused light beams in the front-rear direction of the optical axis, respectively, and the condensing lens is emitted from the diffuse light source of the same-shaped declination measuring device disposed at a predetermined position in the front-rear direction of the optical axis. Two diffused light sources are formed by condensing at least a part of the diffused light flux formed and forming an image on the imaging plate, and sandwiching the condensing lens between the pair of polarization reflecting prisms on the optical axis of the condensing lens. Have strength direction anisotropy, The polarized diffused light beam emitted in the direction perpendicular to the optical axis is reflected by the reflection surface of the polarization reflecting prism and emitted in the front-rear direction of the optical axis, and is disposed at a predetermined position in the front-rear direction of the optical axis. The polarized diffused light beam emitted from the diffused light source and incident on one polarization reflection prism is transmitted through the reflection surface and collected by the condenser lens, and is reflected by the reflection surface of the other polarization reflection prism and is reflected on the imaging plate. It is configured to form an image. Further, a λ / 2 wavelength plate is disposed between one diffusion light source and one polarization reflecting prism, and the λ / 2 wavelength plate is an intensity of the polarized diffused light beam from the diffusion light source that transmits the λ / 2 wavelength plate. Only the polarization plane may be rotated by 90 ° while maintaining the directional anisotropy.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 3 is a schematic diagram showing the intensity direction anisotropy of the diffused light beam emitted from the light source according to the present embodiment. As the diffusion light source 2 used in the present embodiment, a semiconductor laser light emitting element having a direction anisotropy in the direction intensity distribution of the emitted diffused light beam L is used. As shown in the figure, the equal intensity distribution curve of the diffused light beam L emitted from the diffusion light source 2 is a large diffusion angle w in the major axis direction. l And a small diffusion angle w in the minor axis direction s It has a long oval shape. The polarization plane of the diffused light beam L is a polarization plane pd parallel to the major axis direction of the ellipse or a polarization plane pd ′ parallel to the minor axis direction.
[0021]
Thus, by using the diffused light source 2 having a large intensity direction anisotropy in the biaxial direction, the diffused light beam L does not diffuse so much in the short axis direction but diffuses widely in the long axis direction. Therefore, the intensity attenuation characteristic with respect to the light receiving distance is not a square of the distance, but has a characteristic that attenuates in proportion to the distance. That is, in this embodiment, the diffused light beam L emitted from the semiconductor laser light-emitting element has a large intensity direction anisotropy in the biaxial direction, so that the diffused light beam L is gentle with respect to the light receiving distance. Since the diffused light source 2 having the intensity attenuation characteristic can be obtained, the interval between the deflection angle measuring devices to be arranged can be made relatively large without deteriorating the measurement accuracy.
[0022]
FIG. 1 is a perspective view schematically showing the internal configuration of the declination measuring apparatus according to the first embodiment of the present invention. In the figure, reference numerals 2a and 2b denote diffused light sources composed of semiconductor laser light emitting elements that are spaced apart from each other by a predetermined distance in the direction perpendicular to the optical axis C and are disposed at 90 ° different mounting angles around the optical axis C. 6 Is the diffused light flux L of the diffused light source 2a 1 It is a λ / 2 wavelength plate arranged at a position facing the injection port. In addition, the same code | symbol is attached | subjected to the part which can be considered to be the same as that of a prior art example, and the duplicate description is abbreviate | omitted. The polarization planes of the diffuse light sources 2a and 2b are parallel and perpendicular to the optical axis C in the horizontal plane, respectively, and the diffused light beam L 1 , L 2 The strength direction anisotropy is set so that the major axis direction is parallel to the horizontal plane. Further, the λ / 2 wave plate 6 has a main cross section of the diffused light beam L of the diffused light source 2a. 1 Are arranged so as to be inclined at an angle of 45 ° with respect to the plane of polarization.
[0023]
Diffused light beam L emitted from diffused light source 2a 1 As described above, the intensity direction anisotropy is set so that the major axis direction is parallel to the horizontal plane, and the polarization plane is set to be parallel to the optical axis C in the horizontal plane. As is well known, the plane of polarization rotates by 90 ° in the process of being incident on and transmitted through the plate 6. Therefore, the diffused light beam L 1 Is incident on the polarization reflecting prism 3a, the polarization plane has a vertical direction in the drawing, that is, the polarization plane pd1 of S-polarized light, and the intensity direction anisotropy is in a state where the major axis direction is parallel to the horizontal plane. It has become. In this way, the diffused light beam L incident on the polarization reflecting prism 3a. 1 Since the polarization plane pd1 of the light is in the vertical direction, the diffused light beam L incident on the reflection surface of the polarization reflection prism 3a 1 Almost entirely reflects 90 ° and propagates along the optical axis C. Diffuse luminous flux L 1 The anisotropy of the strength direction of the material is such that its major axis is parallel to the horizontal plane, so it does not diffuse so much in the vertical direction, but diffuses and propagates widely in the almost horizontal direction. Attenuates in proportion to distance.
[0024]
In this way, the diffused light beam L emitted from the same-shaped declination measuring device 1 adjacent to the left side along the optical axis C in FIG. 1 Propagates toward the declination measuring device 1 while diffusing in the horizontal direction. Diffuse luminous flux L 1 Is diffused in the horizontal direction, so that the deflection angle measuring apparatus 1 adjacent to the left side arrives at the position slightly away from the optical axis C without being attenuated so much and enters the polarization reflecting prism 3b. . This incident diffused light beam L 1 Since the polarization plane pd1 of the light beam is in the vertical direction, almost all of the light is transmitted without being reflected by the reflection surface inclined by 45 ° with respect to the horizontal plane, and is collected by the condenser lens 4 and then polarized. The light enters the reflecting prism 3a. Since the reflecting surface of the polarization reflecting prism 3a faces the vertical direction, the diffused light beam L 1 While being condensed, almost all of the light is reflected by 90 ° on the reflecting surface and forms an image on the imaging plate 5a. The light reception signal output from the CCD at the imaging position is transferred to the position calculation device 8 described in the conventional example, where the diffused light beam L 1 A line segment m connecting the declination measuring device 1 that has emitted and the reference point of the declination measuring device 1 A And the deviation angle formed by the optical axis C is calculated.
[0025]
On the other hand, the diffused light beam L emitted from the diffusion light source 2b of the same-shaped deviation angle measuring apparatus 1 adjacent to the right side along the optical axis C in FIG. 2 As described above, the intensity direction anisotropy is set so that the major axis direction is parallel to the horizontal plane and the polarization plane is perpendicular to the optical axis C in the horizontal plane. 2 Is incident on the polarization reflecting prism 3b, is almost entirely reflected by 90 [deg.] On the reflecting surface inclined by 45 [deg.] With respect to the horizontal plane, and diffuses and propagates widely in the horizontal direction along the optical axis C on the left side. Diffused light beam L propagated from the same-shaped declination measuring device 1 adjacent to the right side 2 Is diffused in the horizontal direction, and even if the declination measuring device 1 is at a position slightly away from the optical axis C, it arrives without much attenuation and enters the polarization reflecting prism 3a. Since the reflecting surface of the polarization reflecting prism 3a faces the vertical direction, the diffused light beam L having the horizontal polarizing surface pd2 is used. 2 After being reflected by the reflecting surface, almost all of the light is transmitted and condensed by the condenser lens 4 and then enters the polarization reflecting prism 3b.
[0026]
Since the reflecting surface of the polarization reflecting prism 3b is set at an angle of 45 ° with respect to the horizontal plane, the diffused light beam L 2 While being condensed, almost all of the light is reflected by 90 ° on the reflecting surface and forms an image on the imaging plate 5b. The light reception signal output from the CCD at the image forming position is transferred to the position calculation device 8 as described above, where the diffused light beam L 2 A line segment m connecting the declination measuring device 1 that has emitted and the reference point of the declination measuring device 1 B And the deviation angle formed by the optical axis C is calculated. A line segment m that connects the deviation measuring device 1 adjacent to the left side of the optical axis C and the reference point of the deviation measuring device 1. A And the line m connecting the deviation angle formed by the optical axis C and the deviation measuring device 1 adjacent to the right side of the optical axis C and the reference point of the deviation measuring device 1 B Line segment m from the angle of deviation formed by the optical axis C A And line segment m B Is calculated. In this way, the angle Φ can be obtained regardless of the absolute direction of the optical axis C.
[0027]
Next, a line segment m connecting the deviation measuring device 1 adjacent to the right side of the optical axis C measured by a laser distance measuring device (not shown) and the reference point of the deviation measuring device 1. B , The relative position of the reference point of the deviation measuring device 1 adjacent to the right side of the optical axis C with respect to the reference point of the deviation measuring device 1 is determined. In the same manner, since the relative positions of the reference points of adjacent declination measuring devices 1 are similarly determined one after another, the coordinate position is first determined in advance, for example, the declination measuring device installed in the start-up reaction The absolute position of the reference point of the excavator located at the tip of the underground mine with respect to one reference point is determined.
[0028]
As described above, in this embodiment, as the diffusion light sources 2a and 2b, a semiconductor laser light emitting element having intensity direction anisotropy and having a major axis direction and a polarization plane parallel to each other, the structure is simplified, and In order to reduce the size, the diffused light beam L emitted from one diffused light source 2a using the λ / 2 wave plate 6 is used. 1 Only by rotating the plane of polarization of only the diffused light beam L emitted from the diffused light sources 2a and 2b. 1 , L 2 Both are reflected almost 90 degrees at the reflecting surfaces of the polarization reflecting prisms 3a and 3b, respectively, and the polarizing surfaces have different directions in the vertical direction and the horizontal direction, but are both widely diffused and propagated in the horizontal direction. In addition, the diffused light beam L received from the adjacent declination measuring device 1 can be 1 , L 2 Can be transmitted through the reflecting surfaces of the polarization reflecting prisms 3b and 3a that are incident first and led to the condensing lens 4 to be condensed.
[0029]
4 and 5 are diagrams for explaining the circumstances of this side, and FIG. 4 is a perspective view schematically showing the internal configuration of the deflection angle measuring apparatus when the λ / 2 wavelength plate 6 is not used. These are the schematic diagrams which show the light reception state of the kth declination measuring apparatus arrange | positioned in an underground tunnel. The irradiation light emitted from the light source is propagated along the optical axis C, and at least a part of the irradiation light emitted from the other declination measuring device 1 is received, so that it is in the vicinity of the extension line of the optical axis C. In order to accurately measure the declination Φ formed by two line segments connecting the reference points of the declination measuring apparatus 1 adjacent to both sides of the arrangement, the polarized light sources 2a and 2b are used as the light sources, and the optical axis C A pair of polarized light reflecting prisms 3a and 3b are opposed to each other with the condenser lens 4 sandwiched therebetween, and the 90 ° mounting angle at which the polarized light source 2a and the imaging plate 5a and the polarized light source 2b and the imaging plate 5b are orthogonal to the optical axis C are different. Diffuse light beams L emitted from the polarization light sources 2a and 2b are reflected by the reflecting surfaces of the polarization reflection prisms 3a and 3b. 1 ″, L 2 A configuration arranged so as to be parallel to the plane of polarization is an inevitable configuration.
[0030]
FIG. 4 specifically shows this configuration, and in this case, the diffused light beam L propagating along the optical axis C is shown. 1 ″, L 2 As shown in the figure, the diffused light beam L reflected by the reflecting surface of the polarization reflecting prism 3b 2 Is a light beam that diffuses widely in the horizontal direction, but the diffused light beam L reflected by the reflecting surface of the polarization reflecting prism 3a. 1 ″ Is a light beam that diffuses widely in the vertical direction. Therefore, an attempt is made to measure the position of the excavator located at the tip of the underground mine by arranging such declination measuring devices 1 at intervals in the underground mine. Then, as shown in FIG. 5, the kth declination measuring device 1 k Deviation measuring device 1 adjacent to the front of k + 1 To declination measuring device 1 k Diffused luminous flux L emitted toward k + 1 Is a light beam that diffuses widely in the horizontal direction, so the declination measuring device 1 k Is easily received, but the deflection angle measuring apparatus 1 k Deviation measuring device 1 next to the back k-1 To declination measuring device 1 k Diffused luminous flux L emitted toward k-1 Is a light beam that diffuses widely in the vertical direction. k It is hard to receive light.
[0031]
In this way, the diffused light beam L emitted in one direction 1 When a plurality of declination measuring devices 1 ′, which are light fluxes diffusing widely in the vertical direction, are arranged at intervals in the underground mine, the position of the excavator located at the tip in the underground mine is adjacent to each other. Even if the declination measuring device 1 is arranged at a position slightly deviated from the optical axis C, the diffused light beam (for example, the diffused light beam L in FIG. k-1 ) Cannot be received, and therefore the position of the excavator cannot be measured.
[0032]
Therefore, in this embodiment, the installation direction of one polarized light source 2a is rotated by 90 °, and the diffused light beam L 1 In the horizontal direction, the polarization plane of the light is rotated 90 ° with the λ / 2 wave plate 6 so as to be directed in the vertical direction, and is incident parallel to the reflection surface of the polarization reflecting prism 3a. So that almost the entire amount is reflected by 90 °. Thus, the diffused light beam L emitted from the declination measuring device 1 1 , L 2 Can be used as a light beam that diffuses in the horizontal direction more widely than the other directions, and when the position of the excavator is measured in a curved construction that is propelled along a curved path that curves in the horizontal direction, the diffused light beam L 1 , L 2 By effectively using the energy, it is possible to easily receive light even if the adjacent declination measuring devices 1 are arranged at positions slightly deviated from the optical axis C. Therefore, a small number of declination measuring devices 1 can be obtained. It is possible to measure the position of the excavator with high accuracy simply by placing it in the underground mine.
[0033]
In this embodiment, the emitted diffused light beam L 1 , L 2 Diffusing light sources 2a and 2b composed of semiconductor laser light emitting elements having the same direction of diffusion and polarization plane are used. Therefore, a λ / 2 wavelength plate 6 is arranged in front of one of the diffusion light sources 2a to change the polarization plane. Although it had to be rotated by 90 °, it is not necessary to arrange the λ / 2 wavelength plate 6 if a semiconductor laser light emitting device having a diffusion direction and a polarization plane direction different by 90 ° is used for one diffusion light source 2a. . FIG. 2 is a perspective view schematically showing the internal configuration of the deflection angle measuring apparatus according to the second embodiment of the present invention, and the configuration of the deflection angle measuring apparatus 1 is almost the same as that of the conventional example. However, as described above, one diffusion light source 2a uses a semiconductor laser light emitting element in which the diffusion direction and the direction of the polarization plane are different by 90 °. As a result, the diffused light beam L diffusing from the pair of polarization reflecting prisms 3a and 3b in the front-rear direction along the optical axis C and in the horizontal direction wider than the other directions is the same as in the first embodiment. 1 , L 2 Can be propagated. When measuring the declination in a curved path that curves in the vertical direction, of course, the spreading direction of the diffused light beam emitted from the diffusing light source may be set so as to diffuse more widely in the vertical direction than in other directions. .
[0034]
【The invention's effect】
As described above, according to the first aspect of the present invention, the two diffused light sources respectively arranged at the predetermined positions in the front-rear direction of the optical axis connect the reference point and the base point set to them respectively. Since a diffused light beam having intensity direction anisotropy that diffuses more widely in one plane direction including two line segments than the other direction is emitted, the declination in a curved path that curves along one plane is parallel Therefore, even if the distance from the diffusion light source is long, the amount of received light is not significantly reduced, and the energy of the diffused light beam can be used effectively.
According to the second aspect of the present invention, the declination measuring device includes two diffused light sources that respectively emit diffused light beams in the front-rear direction of the optical axis, and the condenser lens has a predetermined length in the front-rear direction of the optical axis. At least a part of the diffused light beam emitted from the diffuse light source of the same-shaped declination measuring device arranged at each position is condensed and imaged on the imaging plate, so at a plurality of locations along the curved path When measuring the declination, it is possible to measure the declination by simply disposing the same declination measuring device at the measurement location. Therefore, the declination measurement operation can be performed very easily.
[0035]
According to the third aspect of the present invention, the two diffused light sources have anisotropy in the intensity direction, and the polarized diffused light beams emitted in the direction perpendicular to the optical axis of the condenser lens are reflected by the polarized light reflecting prism. The polarized diffused light flux that is reflected by the surface and exits in the front-rear direction of the optical axis, and is emitted from a diffused light source disposed at a predetermined position in the front-rear direction of the optical axis and incident on one polarization reflecting prism. Since it is configured to pass through the reflecting surface and be condensed by the condensing lens, reflected by the reflecting surface of the other polarization reflecting prism and imaged on the imaging plate, only one condensing lens can be used from both directions. The propagating polarized diffused light beam can be condensed and imaged on the imaging plate, and the base point of another declination measuring device adjacent in the front-rear direction from the base point at which the condensing lens is provided with respect to the optical axis. The deviation angle is accurately calculated as the deviation of the expected deviation angle. It can be constant.
[0036]
According to the fourth aspect of the present invention, the λ / 2 wave plate disposed between the one diffused light source and the one polarized light reflecting prism has the intensity direction anisotropy of the polarized diffused light beam from the diffused light source that transmits the λ / 2 wavelength plate. While maintaining, only the polarization plane of the polarized diffused light beam emitted from the diffused light source in the direction perpendicular to the optical axis is rotated by 90 °, so that the diffusion direction of the polarized diffused light beam and the direction of the polarization plane are the same 2 By using two diffused light sources, it is possible to emit diffused light fluxes having intensity direction anisotropy that substantially diffuses only in one plane direction.
[0037]
According to the fifth aspect of the present invention, since the semiconductor laser light emitting element is used as the diffusion light source, the diffusion light source can be configured with relatively versatile electronic components. Sticking can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing an internal configuration of a declination measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a perspective view schematically showing an internal configuration of a declination measuring apparatus according to a second embodiment of the present invention.
FIG. 3 is a schematic diagram showing intensity direction anisotropy of a diffused light beam emitted from a light source according to the present embodiment.
FIG. 4 is a perspective view schematically showing an internal configuration of a declination measuring apparatus when a λ / 2 wavelength plate is not used in the first embodiment of the present invention.
FIG. 5 is a schematic diagram showing the light receiving state of the kth declination measuring device arranged in the underground mine.
FIG. 6 is a perspective view schematically showing an internal configuration of a declination measuring apparatus according to a conventional example.
FIG. 7 is an explanatory diagram for explaining a measurement method for measuring the underground excavation position of the excavator with the declination measuring apparatus according to the conventional example.
[Explanation of symbols]
1 Deviation measuring device
2,21 (a, b) Diffuse light source
3 (a, b) Polarization reflecting prism
4 condenser lens
5 (a, b) Imaging board
6 λ / 2 wave plate
7 digging machine
8 Position calculation device
9 Display device
11 underground mine
L 1 , L 2 Diffuse luminous flux
pd1, pd2 polarization plane
