JP3901318B2

JP3901318B2 - Optical component angle measurement method and apparatus

Info

Publication number: JP3901318B2
Application number: JP34750397A
Authority: JP
Inventors: 浩太小川
Original assignee: Olympus Corp
Current assignee: Olympus Corp
Priority date: 1997-12-17
Filing date: 1997-12-17
Publication date: 2007-04-04
Anticipated expiration: 2017-12-17
Also published as: JPH11183148A

Description

【０００１】
【発明の属する技術分野】
本発明は、光学部品の２つの面の頂角を測定する角度測定方法とその装置に関する。
【０００２】
【従来の技術】
従来、光学部品の２つの面の頂角を測定する技術には、例えば、「面方位測定装置」として、特開平６−１６７３２５号公報所載の技術が開示されている。図７を用いて、この技術を説明する。図７において、基台１２１には、該基台１２１に略垂直な軸Ｏを中心として回転自在なように試料台１０３およびスウィーベルアーム１０４がそれぞれ設けられ、このスウィーベルアーム１０４に、試料台１０３上に載置された試料１０１の被測定面から反射されてくる光を観測するための望遠鏡１５１が取り付けられている。なお、試料台１０３には該試料台１０３上に載置された試料１０１の水平方向に対する傾斜角度を調整する傾斜ネジ１０３ａを備えた傾斜角度調整機構が設けられており、一方、基台１２１上には、スウィーベルアーム１０４の回転角度を読み取る為のロータリーエンコーダ１２１ａが内蔵されている。ロータリーエンコーダ１２１ａは、試料台１０３およびスウィーベルアーム１０４の回転角度座標に対応する信号を発生して処理装置１０９に送出する。
【０００３】
望遠鏡１５１は、オートコリメータと同様の構造となっており、試料１０１の被測定面に対向して配置される鏡筒前部に設けられた対物レンズ１５１ａおよびこの対物レンズ１５１ａの焦点位置であって鏡筒後部に設けられた撮像素子１５１ｂからなる観測光学系と、対物レンズ１５１ａを共通にし、該対物レンズ１５１ａと撮像素子１５１ｂとの間に設けられたビームスプリッタ１５１ｃによって観測光学系外に分岐して形成された光路上において撮像素子１５１ｂと光学的に共役な位置に設けられた投影用指標１５１ｄ及び投影用光源１５１ｅからなる投影光学系とを有する。投影用指標１５１ｄの光はビームスプリッタ１５１ｃで反射して対物レンズ１５１ａによって平行光にされて外部に出射され、試料面に入射する。試料１０１の被測定面で反射された光は、同じ対物レンズ１５１ａで集光され、ビームスプリッタ１５１ｃを通過して投影用指標１５１ｅとは光学的に共役な位置に配置された撮像素子１５１ｂ上に焦点を結ぶ。つまり、投影用指標１５１ｄの像が撮像素子１５１ｂ上に結像される。
【０００４】
撮像素子１５１ｂは、例えば、２次元ＣＣＤのように、多数の光検出素子を平面上に配列してそれぞれを画素としたもので、処理装置１０９によって制御され、対物レンズ１５１ａによって結像された光の像を電気的信号に変換し、処理装置１０９に送出する。処理装置１０９は、マイクロプロセッサその他の情報処理用回路等の必要な回路を内蔵し、表示用のディスプレイ１０９ａを有するもので、所定の指令によりあらかじめ記憶されている所定のプログラムに従ってロータリーエンコーダ１２１ａ、撮像素子１５１ｂ及びレチクルジェネレータ１１０を制御するとともにこれらから送出される角度信号や画像信号その他の信号の処理、必要な演算、もしくは表示を行う処理を実行するものである。
【０００５】
試料たるプリズム１０１の面方位を観測するには、望遠鏡１５１の対物レンズ１５１ａの焦点面に位置検出型の撮像素子１５１ｂを配置し、該撮像素子１５１ｂによって得られる投影用指標像に処理装置１０９による画像処理を含む処理を施すことによって該投影用指標像の位置を求め、この位置とレチクルジェネレータ１１０によって形成されるレチクル（基準指標）の位置並びにロータリーエンコーダ１２１ａによる角度測定値とから各面の方位を自動処理で求めるものである。
【０００６】
【発明が解決しようとする課題】
しかるに、上記従来技術にはつぎのような問題点があった。すなわち、上記従来技術は、プリズムの２つの面の頂角を自動処理で求めることにより、測定精度を向上させている点では優れている。ところが、プリズム自体は、測定する頂角を形成する２つの面に隣接する第３の面を試料台上に載置して保持されている。このため、形状的に保持が困難なプリズム、例えば、微小プリズムや被測定頂角を形成する２つの面に隣接する第３の面が平面でない異形プリズム等を測定する場合、プリズムの保持が不安定となり、測定精度が低下するという問題点があった。
【０００７】
本発明は、上記従来の問題点に鑑みてなされたもので、請求項１に係る発明の課題は、形状的に保持が困難な光学部品であっても、安定した保持を保証し、測定精度に優れた光学部品の角度測定方法を提供することである。
請求項２、３または４に係る発明の課題は、請求項１に係る発明の光学部品の角度測定方法を容易に実施するための角度測定装置を提供することである。
【０００８】
【課題を解決するための手段】
上記課題を解決するために、請求項１に係る発明の光学部品の角度測定方法は、光学部品の２つの面で形成された被測定頂角を測定する光学部品の角度測定方法において、前記光学部品を保持する保持治具の基準面をオートコリメータに向ける工程と、前記オートコリメータを観察し前記保持治具の基準面の反射指標と前記オートコリメータの基準指標とを一致させる工程と、前記光学部品の２つの面のうちの一方である基準面を前記保持治具の基準面に当て付けて保持する工程と、前記保持治具の基準面と前記光学部品の基準面との干渉縞を観察する工程と、前記干渉縞の観察結果によって前記保持治具による前記光学部品の保持状態が良好であることを確認した後、前記保持治具を被測定頂角の称呼角度だけ回転させ前記光学部品の２つの面のうちの他方である被測定面の反射指標を前記オートコリメータで測定する工程と、前記測定した反射指標と前記オートコリメータの基準指標とを比較してズレ量を求め、そのズレ量を被測定頂角の誤差量とする工程とを有する。
【０００９】
請求項２に係る発明の光学部品の角度測定装置は、光学部品の２つの面で形成された被測定頂角を測定する光学部品の角度測定装置において、前記光学部品の２つの面のうちの一方である基準面を当て付けて保持する保持治具と、前記保持治具を所定の角度回転させる回転ステージと、前記光学部品の２つの面のうちの他方である被測定面の面方位を測定するオートコリメータと、前記光学部品の基準面とその基準面を当て付けた保持治具の基準面との干渉縞を観察する観察手段とを具備するものである。
請求項３に係る発明の光学部品の角度測定装置は、請求項２に係る発明の光学部品の角度測定装置において、前記保持治具の基準面が鏡面加工されているものである。
請求項４に係る発明の光学部品の角度測定装置は、請求項２または請求項３に係る発明の光学部品の角度測定装置において、前記保持治具の基準面に、前記光学部品の基準面を吸着する吸着口を設けたものである。
【００１０】
すなわち、請求項１に係る発明の光学部品の角度測定方法は、光学部品を保持する保持治具の基準面をオートコリメータに向ける。そして、オートコリメータを観察し、保持治具の基準面とオートコリメータの基準面とを一致させる。光学部品の２つの面のうちの一方である基準面を保持治具の基準面に当て付け保持し、保持治具の基準面と光学部品の基準面との干渉縞を観察する。さらに、干渉縞の観察結果によって保持治具による光学部品の保持状態が良好であることを確認した後、保持治具を被測定頂角の称呼角度だけ回転させ、光学部品の２つの面のうちの他方である被測定面の反射指標をオートコリメータで測定し、測定した反射指標とオートコリメータの基準指標とを比較してズレ量を求め、そのズレ量を被測定頂角の誤差量とする。これによって、光学部品の２つの面で形成された被測定頂角が測定される。
【００１１】
また、請求項２に係る発明の光学部品の角度測定装置は、光学部品の２つの面のうちの一方である基準面を当て付けて保持治具に保持する。そして、光学部品の基準面とその基準面を当て付けた保持治具の基準面との干渉縞を干渉縞観察手段で観察する。回転ステージによって保持治具を所定の角度回転させ、光学部品の２つの面のうちの他方である被測定面の面方位をオートコリメータで測定する。これによって、光学部品の２つの面で形成された被測定頂角が測定される。
さらに、請求項３に係る発明の光学部品の角度測定装置は、鏡面加工されている保持治具の基準面で光学部品を保持する。
さらにまた、請求項４の発明に係る光学部品の角度測定装置は、保持治具に設けられた吸着口によって保持治具の基準面に光学部品を吸着する。
【００１２】
【発明の実施の形態】
本発明の実施の形態における光学部品の角度測定装置は、主に、光学部品としてのプリズムの基準面を当て付けて保持する保持治具と、保持治具を所定の角度に回転させる回転ステージと、プリズムの被測定面の面方位を測定するオートコリメータと、プリズムの基準面と保持治具の基準面との干渉縞を観察する干渉縞観察手段とから構成される。
【００１３】
また、上記構成の光学部品の角度測定装置を用いたプリズムの角度測定方法では、まず、保持治具のプリズムを当て付ける基準面の面方位をオートコリメータにより観察し、オートコリメータの基準指標に合わせてゼロ設定する。そして、プリズムの被測定頂角を形成する２つの面のうちの１つの面を基準面、他の面を被測定面とし、プリズムの基準面を保持治具の基準面に当て付けて保持する。その際に、干渉縞観察手段にて、保持治具の基準面とプリズムの基準面との干渉縞を観察し、密着度を観察する。干渉縞の観察結果が良好の場合は、プリズムの基準面と保持治具の基準面とを同一面とみなす。つぎに、回転ステージを被測定頂角の称呼角度分だけ回転させ、プリズムの被測定面の面方位をオートコリメータにより観察し、オートコリメータの基準指標とのズレ量を角度測定誤差として測定する。
【００１４】
本発明の実施の形態においては、光学部品として、三角プリズムを例にして説明するが、三角プリズムの被測定頂角を形成する２つの面のうちの一方を基準面として測定できるので、ダハプリズムなどの異形プリズムや、レンズとプリズムとが一体化された複合光学部品などの頂角も測定可能である。また、保持が困難な微小プリズムの頂角でも本実施の形態で示す角度測定装置と方法により測定することができる。以下、具体的な実施の形態により説明する。
【００１５】
（実施の形態１）
図１〜図２は実施の形態１を示し、図１は光学部品の角度測定装置の概略構成図、図２はプリズムの角度測定方法を示す工程図である。ここで、図２（ｂ），（ｃ），（ｄ）は図１のＡ方向から保持治具を見た図である。
【００１６】
図１において、光学部品の角度測定装置は、光学部品保持部１１と、オートコリメータ部１２と、干渉縞観察部１３とから構成されている。光学部品保持部１１は、光学部品を保持するガラス製の保持治具１と、光学部品を保持した保持治具１を水平方向に回転させる回転ステージ２と、保持治具１に接続された真空発生装置６とからなっている。保持治具１は回転ステージ２の上面に固着され、その上部には、回転ステージ２の回転軸Ｉを通って垂直方向に平面をなす基準面１ａが形成されている。基準面１ａは鏡面加工が施され、光学部品を当て付けることができる。基準面１ａには、吸着穴１ｂが穿設され、吸着穴１ｂは基準面１ａの背面に凸設された空圧継手６ａおよび空圧チューブ６ｂを介して真空発生装置６に接続されており、真空圧によって光学部品を基準面１ａに保持することができる。回転ステージ２は、回転軸Ｉを中心に、その上面に固着した保持治具１を手動で回転させ、その回転量を、内蔵するエンコーダ（図示省略）に接続された回転量表示装置２Ａに表示する。
【００１７】
光学部品保持部１１の右側には、オートコリメータ部１２が配置されている。オートコリメータ部１２は、光学部品の頂角を測定するオートコリメータ４と、オートコリメータ４を支持する支持機構５とからなっている。オートコリメータ４は、保持治具１の基準面１ａに正対するようにほぼ水平に支持され、支持機構５の２つの調整軸により、水平方向（矢印θ1 ）および垂直方向（矢印θ2 ）に回転しオートコリメータ４の向きを調整することができる。光学部品保持部１１の左側には、干渉縞観察部１３が配置されている。干渉縞観察部１３は、干渉縞観察手段としての干渉縞観察カメラ３と、これに接続されたカメラモニタ３Ａと、干渉縞を発生させるための光源７とからなっている。干渉縞観察カメラ３は、保持治具１の基準面１ａの背面に正対して配設され、光源７からの光によって発生し、ガラス製の保持具１の基準面１ａと光学部品の基準面との密着状態によって変化する干渉縞を観察することができる。その状況は、干渉縞観察カメラ３に接続されたカメラモニタ３Ａに表示される。
【００１８】
つぎに、上記構成の角度測定装置を用いた光学部品の角度測定方法について説明する。図２（ａ）に示すように、光学部品としてのプリズム８は、三角プリズムであり、本実施の形態では、Ａ面とＢ面とにより形成された被測定頂角αの角度誤差を測定するものである。
【００１９】
まず、図２（ｂ）に示すように、保持治具１の基準面１ａの法線方向をオートコリメータ４の方向に回転ステージ２を回転させて合わせる。そして。オートコリメータ４を観察して、基準面１ａの反射指標がオートコリメータ４の基準指標と一致するように、支持機構５の２つの調整軸を矢印θ1 、θ2 の方向に回動して調整する（コリメータゼロ設定完了）。
【００２０】
つぎに、図２（ｃ）に示すように、光学部品としてのプリズム８の基準面であるＡ面を保持治具１の基準面１ａに、吸着穴１ｂにより吸着させて保持させる。このとき、プリズム８のＡ面と保持治具１の基準面１ａとの間にゴミや塵が挟まり、密着度を低下させる可能性があるので、干渉縞観察カメラ３によりプリズム８のＡ面と保持治具１の基準面１ａとの間に発生する干渉縞を撮影する。測定者は、カメラモニタ３Ａに写し出された干渉縞画像を見て密着度を確認する。干渉縞の状態による密着度の優劣判断は、干渉縞の整列状態や間隔により別途に定められた基準により判断される。密着度が低い場合は、再度プリズム８の吸着保持をやり直す。この作業により、保持治具１の基準面１ａとプリズム８のＡ面とがオートコリメータ４に対する同一面とみなせる（プリズム保持完了）。
【００２１】
つぎに、図２（ｄ）に示すように、回転量表示装置２Ａを確認しながら、回転ステージ２により保持治具１を被測定頂角αの称呼角度だけ正確に回転させる。するとプリズム８の被測定面であるＢ面の法線方向がオートコリメータ４の方向に向き、プリズム８のＢ面の面方位がオートコリメータ４により観察可能となる。そして、プリズム８のＢ面の反射指標とオートコリメータ４の基準指標とのズレ量を測定して、この値が被測定頂角αの誤差量となる（コリメータズレ量測定）。
【００２２】
本実施の形態によれば、プリズムの基準面を保持治具の基準面に当て付けて保持し、被測定プリズムの保持状態を干渉縞により確認して測定を行うので、いかなるプリズム、例えば形状的に保持が困難なプリズムであっても確実に保持することができ、被測定プリズムの保持状態による測定誤差を抑制し、測定精度を向上させることができる。
【００２３】
（実施の形態２）
図３〜図６は実施の形態２を示し、図３は光学部品の角度測定装置の概略構成図、図４は図３のＢ矢視図、図５は被測定プリズムの斜視図、図６はプリズムの角度測定方法を示す工程図である。図３において、光学部品の角度測定装置を構成する光学部品保持部２１、オートコリメータ部１２および干渉縞観察部１３のうち、オートコリメータ部１２と干渉縞観察部１３とは、実施の形態１と同一であり、光学部品保持部２１のみが異なるため、異なる部分のみ説明し、同一の部材には同一の符号を付し説明を省略する。
【００２４】
図３および図４において、光学部品の角度測定装置の光学部品保持部２１は、光学部品を保持するガラス製の保持治具１と、光学部品を保持した保持治具１を垂直方向に回転させる第２の回転ステージ１０と、Ｌ字型アーム９を介して第２の回転ステージ１０を水平方向に回転させる回転ステージ２と、保持治具１に接続された真空発生装置６とからなっている。実施の形態１と同様に、保持治具１には、垂直方向に平面をなす基準面１ａが形成されており、基準面１ａは鏡面加工が施され、光学部品を当て付けることができる。また、基準面１ａには、吸着穴１ｂが穿設され、吸着穴１ｂは基準面１ａの背面に凸設された空圧継手６ａおよび空圧チューブ６ｂを介して真空発生装置６に接続されており、真空圧によって光学部品を基準面１ａに保持することができる。
【００２５】
回転ステージ２は、回転軸Ｉを中心に、その上面に配設したＬ字型アーム９に固着された第２回転ステージ１０を手動で回転させ、その回転量を、内蔵するエンコーダ（図示省略）に接続された回転量表示装置２Ａに表示する。第２回転ステージ１０は、回転軸Ｏを中心に、その側面に配設した保持治具１を手動で回転させ、その回転量を、回転ステージ２と同様に内蔵するエンコーダ（図示省略）に接続された第２回転量表示装置１０Ａに表示する。また、回転軸Ｉと回転軸Ｏとは、保持治具１の基準面１ａ上に穿設された吸着穴１ｂの開口部の位置で直交するように構成されている。
【００２６】
つぎに、上記構成の角度測定装置を用いた光学部品の角度測定方法について説明する。図５に示すように、光学部品としてのプリズム２２は、三角プリズムであり、本実施の形態では、Ａ面とＢ面とにより形成された被測定頂角αおよびＡ面とＣ面とにより形成された被測定頂角βのそれぞれの角度誤差を測定するものである。
【００２７】
まず、被測定頂角αの測定を行う。その測定方法は、保持治具１の基準面１ａをオートコリメータ４に正対させて（コリメータゼロ設定）、つぎにプリズム２２のＡ面を保持治具１の基準面１ａに吸着させて干渉縞が正常であることを確認してから（プリズム保持完了）、回転ステージ２を被測定角αの称呼角度だけ回転させ、Ｂ面をオートコリメータ４によって誤差量測定を行う（コリメータズレ量測定）ものであって、実施の形態１と同様なので、詳細な説明を省略する。
【００２８】
つぎに、被測定頂角αの測定終了後、図６（ａ）に示すように、回転ステージ２を被測定頂角αの称呼角度だけ回転量表示装置２Ａを確認しながら正確に戻す。つぎに、第２回転ステージ１０を被測定頂角βの称呼角度だけ第２回転量表示装置１０Ａを確認しながら正確に回転させる。すると、図６（ｂ）に示すように、プリズム２２のＣ面の法線方向がオートコリメータ４の方向に向き、プリズム２２のＣ面の面方位がオートコリメータ４により観察可能となる。そして、プリズム２２のＣ面の反射指標とオートコリメータ４の基準指標とのズレ量を測定して、この値が被測定頂角βの誤差量となる。
【００２９】
本実施の形態によれば、実施の形態１の効果に加え、被測定プリズムの共通面を持つ２つの頂角がプリズムを置き替えることなく測定可能となるので、測定時間を短縮することができる。
【００３０】
なお、上述の具体的な実施の形態から、つぎのような構成の技術的思想が導き出される。
（付記）
（１）プリズムの被測定頂角を形成する２つの面のうちの１つの面を基準面、他の面を被測定面とし、プリズムの頂角を測定するプリズムの角度測定方法において、
プリズムを保持する保持治具の基準面の法線方向をオートコリメータの方向に合わせ、プリズムの基準面を前記保持治具の基準面に当て付けて保持し、プリズムの基準面と保持治具の基準面との干渉縞を観察し、前記保持治具を被測定頂角の称呼角度だけ回転させ、プリズムの被測定面の反射指標とオートコリメータの基準指標とのズレ量を測定し、ズレ量を測定頂角の誤差量とすることを特徴とするプリズムの角度測定方法。
形状的に保持が困難なプリズムであっても、安定した保持を保証し、測定精度を向上させることができる。
（２）プリズムの基準面を当て付けて保持する保持治具と、該保持治具を所定の角度回転させる回転ステージと、プリズムの被測定面の面方位を測定するオートコリメータと、前記プリズムの基準面と前記保持治具の基準面との干渉縞を観察する干渉縞観察手段とを具備することを特徴とするプリズムの角度測定装置。
付記（１）記載のプリズムの角度測定方法を容易に実施することができるとともに、測定精度の信頼性を高めることができる。
（３）プリズムの基準面を当て付けて保持する保持治具の基準面が、鏡面加工されていることを特徴とする付記（２）記載のプリズムの角度測定装置。
付記（２）記載の効果に加え、オートコリメータによるゼロ設定を容易にさせるとともに、干渉縞の発生を確実に行わせる。
（４）プリズムの基準面を当て付けて保持する保持治具の基準面に、プリズムの基準面を吸着する吸着口を設けたことを特徴とする付記（２）または（３）記載のプリズムの角度測定装置。
付記（２）または（３）記載の効果に加え、プリズムの保持を容易に行うことができる。
【００３１】
【発明の効果】
請求項１に係る発明の光学部品の角度測定方法によれば、光学部品の基準面を保持治具の基準面に当て付けて保持し、光学部品の基準面と保持治具の基準面との保持状態を干渉縞により確認して測定を行うので、形状的に保持が困難な光学部品であっても、安定した保持を保証し、測定精度を向上させることができる。請求項２に係る発明の光学部品の角度測定装置によれば、請求項１に係る発明の光学部品の角度測定方法を容易に実施することができるとともに、測定精度の信頼性を高めることができる。
請求項３に係る発明の光学部品の角度測定装置によれば、請求項２に係る発明の効果に加え、オートコリメータによるゼロ設定を容易にさせるとともに、干渉縞の発生を確実に行わせる。
請求項４に係る発明の光学部品の角度測定装置によれば、請求項２または請求項３に係る発明の効果に加え、光学部品の保持を容易に行うことができる。
【図面の簡単な説明】
【図１】実施の形態１の光学部品の角度測定装置の概略構成図である。
【図２】実施の形態１のプリズムの角度測定方法を示す工程図である。
【図３】実施の形態２の光学部品の角度測定装置の概略構成図である。
【図４】実施の形態２の図３のＢ矢視図である。
【図５】実施の形態２の被測定プリズムの斜視図である。
【図６】実施の形態２のプリズムの角度測定方法を示す工程図である。
【図７】従来技術の面方位測定装置を示す概略構成図である。
【符号の説明】
１保持治具
２回転ステージ
３干渉縞観察カメラ
４オートコリメータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an angle measuring method and apparatus for measuring apex angles of two surfaces of an optical component.
[0002]
[Prior art]
Conventionally, as a technique for measuring the apex angles of two surfaces of an optical component, for example, a technique described in Japanese Patent Laid-Open No. 6-167325 is disclosed as a “plane orientation measuring device”. This technique will be described with reference to FIG. In FIG. 7, a base 121 is provided with a sample stage 103 and a swivel arm 104 so as to be rotatable about an axis O substantially perpendicular to the base 121, and the swivel arm 104 is mounted on the sample stage 103. The telescope 151 for observing the light reflected from the surface to be measured of the sample 101 placed on is attached. The sample stage 103 is provided with an inclination angle adjusting mechanism having an inclination screw 103a for adjusting the inclination angle of the sample 101 placed on the sample stage 103 with respect to the horizontal direction. Includes a rotary encoder 121 a for reading the rotation angle of the swivel arm 104. The rotary encoder 121 a generates a signal corresponding to the rotation angle coordinates of the sample stage 103 and the swivel arm 104 and sends it to the processing device 109.
[0003]
The telescope 151 has the same structure as the autocollimator, and is an objective lens 151a provided at the front of the lens barrel that is disposed to face the surface to be measured of the sample 101, and the focal position of the objective lens 151a. The observation optical system including the imaging element 151b provided at the rear part of the lens barrel and the objective lens 151a are used in common, and are branched out of the observation optical system by the beam splitter 151c provided between the objective lens 151a and the imaging element 151b. A projection optical system including a projection index 151d and a projection light source 151e provided at a position optically conjugate with the imaging element 151b on the optical path formed in this manner. The light of the projection index 151d is reflected by the beam splitter 151c, converted into parallel light by the objective lens 151a, emitted to the outside, and incident on the sample surface. The light reflected by the surface to be measured of the sample 101 is collected by the same objective lens 151a, passes through the beam splitter 151c, and is placed on the image sensor 151b disposed at a position optically conjugate with the projection index 151e. Focus. That is, an image of the projection index 151d is formed on the image sensor 151b.
[0004]
The imaging element 151b is a device in which a large number of light detection elements are arranged on a plane and each pixel is formed, such as a two-dimensional CCD, and is controlled by the processing device 109 and imaged by the objective lens 151a. The image is converted into an electrical signal and sent to the processing device 109. The processing device 109 incorporates necessary circuits such as a microprocessor and other information processing circuits, and has a display 109a for display. The processing device 109 is configured to take an image of the rotary encoder 121a according to a predetermined program stored in advance according to a predetermined command. It controls the element 151b and the reticle generator 110, and executes processing of angle signals, image signals, and other signals sent from them, and necessary calculations or processing for display.
[0005]
In order to observe the surface orientation of the prism 101 as the sample, a position detection type imaging device 151b is arranged on the focal plane of the objective lens 151a of the telescope 151, and the projection index image obtained by the imaging device 151b is obtained by the processing device 109. The position of the projection index image is obtained by performing processing including image processing, and the orientation of each surface is determined from this position, the position of the reticle (reference index) formed by the reticle generator 110, and the angle measurement value by the rotary encoder 121a. Is obtained by automatic processing.
[0006]
[Problems to be solved by the invention]
However, the above prior art has the following problems. That is, the above-described conventional technique is excellent in that the measurement accuracy is improved by obtaining the apex angles of the two surfaces of the prism by automatic processing. However, the prism itself is held by placing a third surface adjacent to the two surfaces forming the apex angle to be measured on the sample stage. For this reason, when measuring prisms that are difficult to hold in shape, such as microprisms or deformed prisms in which the third surface adjacent to the two surfaces forming the measured apex angle is not a flat surface, the prism is not retained. There was a problem that the measurement accuracy was lowered due to stability.
[0007]
The present invention has been made in view of the above-described conventional problems, and an object of the invention according to claim 1 is to ensure stable holding even if it is an optical component that is difficult to hold in shape, and to achieve measurement accuracy. It is an object to provide a method for measuring an angle of an optical component excellent in the above.
The subject of the invention which concerns on Claim 2, 3 or 4 is providing the angle measuring apparatus for enforcing the angle measuring method of the optical component of the invention which concerns on Claim 1 easily.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, an optical component angle measurement method according to the first aspect of the present invention is an optical component angle measurement method for measuring a measured apex angle formed by two surfaces of an optical component, wherein the optical component Directing a reference surface of a holding jig for holding a part to an autocollimator, observing the autocollimator, matching a reflection index of a reference surface of the holding jig with a reference index of the autocollimator, and the optical A step of holding a reference surface, which is one of the two surfaces of the component, against the reference surface of the holding jig, and observing interference fringes between the reference surface of the holding jig and the reference surface of the optical component And confirming that the holding state of the optical component by the holding jig is good based on the observation result of the interference fringes, and then rotating the holding jig by a nominal angle of the measured apex angle. Two of The step of measuring the reflection index of the surface to be measured, which is the other of the surfaces, with the autocollimator and the measured reflection index and the reference index of the autocollimator are obtained to obtain a deviation amount, and the deviation amount is measured. And an error amount of the measurement apex angle.
[0009]
An optical component angle measuring device according to a second aspect of the invention is an optical component angle measuring device for measuring a measured apex angle formed by two surfaces of an optical component, wherein the optical component angle measuring device includes: On the other hand, a holding jig that holds and holds a reference surface, a rotation stage that rotates the holding jig by a predetermined angle, and a surface orientation of a measurement surface that is the other of the two surfaces of the optical component An autocollimator to be measured and observation means for observing interference fringes between the reference surface of the optical component and the reference surface of the holding jig to which the reference surface is applied.
An optical component angle measuring apparatus according to a third aspect of the present invention is the optical component angle measuring apparatus according to the second aspect, wherein the reference surface of the holding jig is mirror-finished.
An optical component angle measuring device according to a fourth aspect of the present invention is the optical component angle measuring device according to the second or third aspect, wherein the reference surface of the optical component is provided on the reference surface of the holding jig. An adsorption port for adsorption is provided.
[0010]
That is, in the optical component angle measuring method according to the first aspect of the invention, the reference plane of the holding jig that holds the optical component is directed to the autocollimator. Then, the autocollimator is observed, and the reference surface of the holding jig is matched with the reference surface of the autocollimator. A reference surface which is one of the two surfaces of the optical component is held against the reference surface of the holding jig, and interference fringes between the reference surface of the holding jig and the reference surface of the optical component are observed. Further, after confirming that the holding state of the optical component by the holding jig is good based on the observation result of the interference fringes, the holding jig is rotated by the nominal angle of the apex angle to be measured, The reflection index of the surface to be measured, which is the other of the above, is measured with an autocollimator, the measured reflection index and the reference index of the autocollimator are compared to determine the amount of deviation, and the amount of deviation is taken as the error amount of the measured apex angle . As a result, the measured apex angles formed on the two surfaces of the optical component are measured.
[0011]
The optical component angle measuring apparatus according to the second aspect of the invention applies a reference surface, which is one of the two surfaces of the optical component, and holds the reference surface to the holding jig. Then, interference fringes between the reference surface of the optical component and the reference surface of the holding jig applied with the reference surface are observed by the interference fringe observation means. The holding jig is rotated by a predetermined angle by the rotation stage, and the surface orientation of the surface to be measured, which is the other of the two surfaces of the optical component, is measured with an autocollimator. As a result, the measured apex angles formed on the two surfaces of the optical component are measured.
Furthermore, the optical part angle measuring device according to the third aspect of the invention holds the optical part on the reference surface of the holding jig that is mirror-finished.
Furthermore, the optical component angle measuring device according to the invention of claim 4 sucks the optical component on the reference surface of the holding jig by the suction port provided in the holding jig.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An optical component angle measuring apparatus according to an embodiment of the present invention mainly includes a holding jig that holds and holds a reference surface of a prism as an optical component, and a rotary stage that rotates the holding jig to a predetermined angle. And an autocollimator for measuring the surface orientation of the surface to be measured of the prism, and interference fringe observation means for observing the interference fringe between the reference surface of the prism and the reference surface of the holding jig.
[0013]
In addition, in the prism angle measurement method using the optical component angle measurement apparatus having the above-described configuration, first, the surface orientation of the reference surface against which the prism of the holding jig is applied is observed with an autocollimator and matched with the reference index of the autocollimator. To zero. Then, one of the two surfaces forming the measured vertex angle of the prism is used as a reference surface, the other surface is used as a measured surface, and the reference surface of the prism is applied to the reference surface of the holding jig and held. . At that time, the interference fringe observation means observes the interference fringe between the reference surface of the holding jig and the reference surface of the prism, and observes the degree of adhesion. When the observation result of the interference fringes is good, the reference surface of the prism and the reference surface of the holding jig are regarded as the same surface. Next, the rotary stage is rotated by the nominal angle of the measured apex angle, the surface orientation of the measured surface of the prism is observed with an autocollimator, and the amount of deviation from the reference index of the autocollimator is measured as an angle measurement error.
[0014]
In the embodiment of the present invention, a triangular prism will be described as an example of an optical component. However, since one of two surfaces forming the measured apex angle of the triangular prism can be measured as a reference surface, a roof prism, etc. It is also possible to measure the apex angle of a deformed prism, or a composite optical component in which a lens and a prism are integrated. Further, even the apex angle of a minute prism that is difficult to hold can be measured by the angle measuring apparatus and method shown in this embodiment. Hereinafter, a specific embodiment will be described.
[0015]
(Embodiment 1)
1 to 2 show the first embodiment, FIG. 1 is a schematic configuration diagram of an optical component angle measuring device, and FIG. 2 is a process diagram showing a prism angle measuring method. Here, FIGS. 2B, 2C, and 2D are views of the holding jig viewed from the direction A in FIG.
[0016]
In FIG. 1, the optical component angle measuring device includes an optical component holding unit 11, an autocollimator unit 12, and an interference fringe observation unit 13. The optical component holding unit 11 includes a glass holding jig 1 that holds the optical component, a rotary stage 2 that rotates the holding jig 1 that holds the optical component in the horizontal direction, and a vacuum connected to the holding jig 1. It consists of the generator 6. The holding jig 1 is fixed to the upper surface of the rotary stage 2, and a reference surface 1 a that forms a plane in the vertical direction through the rotation axis I of the rotary stage 2 is formed thereon. The reference surface 1a is mirror-finished and can be applied with an optical component. A suction hole 1b is formed in the reference surface 1a, and the suction hole 1b is connected to the vacuum generator 6 via a pneumatic joint 6a and a pneumatic tube 6b protruding from the back surface of the reference surface 1a. The optical component can be held on the reference surface 1a by the vacuum pressure. The rotary stage 2 manually rotates the holding jig 1 fixed to the upper surface thereof around the rotation axis I, and displays the rotation amount on a rotation amount display device 2A connected to a built-in encoder (not shown). To do.
[0017]
An autocollimator unit 12 is disposed on the right side of the optical component holding unit 11. The autocollimator unit 12 includes an autocollimator 4 that measures the vertex angle of the optical component and a support mechanism 5 that supports the autocollimator 4. The autocollimator 4 is supported substantially horizontally so as to face the reference surface 1a of the holding jig 1, and is rotated in the horizontal direction (arrow θ1) and the vertical direction (arrow θ2) by the two adjusting shafts of the support mechanism 5. The orientation of the autocollimator 4 can be adjusted. An interference fringe observation unit 13 is arranged on the left side of the optical component holding unit 11. The interference fringe observation unit 13 includes an interference fringe observation camera 3 as interference fringe observation means, a camera monitor 3A connected thereto, and a light source 7 for generating interference fringes. The interference fringe observation camera 3 is disposed in front of the back surface of the reference surface 1a of the holding jig 1, and is generated by light from the light source 7, and is formed by the reference surface 1a of the glass holder 1 and the reference surface of the optical component. It is possible to observe interference fringes that change depending on the close contact state. The situation is displayed on the camera monitor 3 </ b> A connected to the interference fringe observation camera 3.
[0018]
Next, a method for measuring the angle of an optical component using the angle measuring apparatus having the above configuration will be described. As shown in FIG. 2A, the prism 8 as an optical component is a triangular prism, and in this embodiment, the angle error of the measured apex angle α formed by the A surface and the B surface is measured. Is.
[0019]
First, as shown in FIG. 2B, the normal direction of the reference surface 1 a of the holding jig 1 is adjusted by rotating the rotary stage 2 in the direction of the autocollimator 4. And then. The autocollimator 4 is observed, and the two adjustment axes of the support mechanism 5 are rotated and adjusted in the directions of arrows θ1 and θ2 so that the reflection index of the reference surface 1a matches the reference index of the autocollimator 4 ( Complete collimator zero setting).
[0020]
Next, as shown in FIG. 2C, the A surface, which is the reference surface of the prism 8 as an optical component, is adsorbed and held on the reference surface 1a of the holding jig 1 through the suction holes 1b. At this time, dust or dust may be caught between the A surface of the prism 8 and the reference surface 1a of the holding jig 1, and the degree of adhesion may be reduced. An interference fringe generated between the holding jig 1 and the reference surface 1a is photographed. The measurer looks at the interference fringe image projected on the camera monitor 3A and confirms the degree of adhesion. Whether the degree of adhesion is superior or inferior depending on the state of the interference fringes is determined based on a separately defined standard based on the alignment state and interval of the interference fringes. When the degree of adhesion is low, the suction holding of the prism 8 is performed again. By this operation, the reference surface 1a of the holding jig 1 and the A surface of the prism 8 can be regarded as the same surface with respect to the autocollimator 4 (prism holding completion).
[0021]
Next, as shown in FIG. 2D, the holding jig 1 is accurately rotated by the nominal angle α of the measured apex angle α by the rotary stage 2 while checking the rotation amount display device 2A. Then, the normal direction of the B surface, which is the surface to be measured of the prism 8, faces the direction of the autocollimator 4, and the surface orientation of the B surface of the prism 8 can be observed by the autocollimator 4. Then, the amount of deviation between the reflection index on the B surface of the prism 8 and the reference index of the autocollimator 4 is measured, and this value becomes the error amount of the measured apex angle α (collimator deviation amount measurement).
[0022]
According to the present embodiment, the prism reference surface is held against the reference surface of the holding jig, and the measurement is performed by checking the holding state of the measured prism with the interference fringes. Even if it is difficult to hold the prism, it can be securely held, measurement errors due to the holding state of the prism to be measured can be suppressed, and measurement accuracy can be improved.
[0023]
(Embodiment 2)
3 to 6 show the second embodiment, FIG. 3 is a schematic configuration diagram of an optical component angle measuring device, FIG. 4 is a view as viewed in the direction of arrow B in FIG. 3, FIG. 5 is a perspective view of a prism to be measured, and FIG. These are process drawings which show the angle measuring method of a prism. In FIG. 3, among the optical component holding unit 21, the autocollimator unit 12, and the interference fringe observation unit 13 constituting the optical component angle measurement device, the autocollimator unit 12 and the interference fringe observation unit 13 are the same as those in the first embodiment. Since they are the same and only the optical component holding part 21 is different, only different parts will be described, and the same members will be denoted by the same reference numerals and description thereof will be omitted.
[0024]
3 and 4, the optical component holding unit 21 of the optical component angle measuring device rotates the glass holding jig 1 holding the optical component and the holding jig 1 holding the optical component in the vertical direction. It consists of a second rotary stage 10, a rotary stage 2 that rotates the second rotary stage 10 in the horizontal direction via an L-shaped arm 9, and a vacuum generator 6 connected to the holding jig 1. . As in the first embodiment, the holding jig 1 is provided with a reference surface 1a that is flat in the vertical direction. The reference surface 1a is mirror-finished and can be applied with an optical component. Further, a suction hole 1b is drilled in the reference surface 1a, and the suction hole 1b is connected to the vacuum generator 6 via a pneumatic joint 6a and a pneumatic tube 6b protruding from the back surface of the reference surface 1a. Thus, the optical component can be held on the reference surface 1a by the vacuum pressure.
[0025]
The rotation stage 2 manually rotates the second rotation stage 10 fixed to the L-shaped arm 9 disposed on the upper surface thereof around the rotation axis I, and the rotation amount is stored in an encoder (not shown). Is displayed on the rotation amount display device 2A connected to. The second rotary stage 10 manually rotates the holding jig 1 disposed on the side surface around the rotation axis O, and the rotation amount is connected to a built-in encoder (not shown) like the rotary stage 2. Is displayed on the second rotation amount display device 10A. Further, the rotation axis I and the rotation axis O are configured to be orthogonal to each other at the position of the opening portion of the suction hole 1 b formed on the reference surface 1 a of the holding jig 1.
[0026]
Next, a method for measuring the angle of an optical component using the angle measuring apparatus having the above configuration will be described. As shown in FIG. 5, the prism 22 as an optical component is a triangular prism. In this embodiment, the prism 22 to be measured is formed by the measured apex angle α formed by the A surface and the B surface and the A surface and the C surface. The angle error of each measured apex angle β is measured.
[0027]
First, the measured vertex angle α is measured. The measuring method is such that the reference surface 1a of the holding jig 1 is directly opposed to the autocollimator 4 (collimator zero setting), and then the A surface of the prism 22 is attracted to the reference surface 1a of the holding jig 1 to cause interference fringes. Is confirmed to be normal (prism holding completed), and the rotation stage 2 is rotated by a nominal angle of the angle α to be measured, and the B surface is subjected to error amount measurement by the autocollimator 4 (collimator displacement amount measurement) And since it is the same as that of Embodiment 1, detailed description is abbreviate | omitted.
[0028]
Next, after the measurement of the measured apex angle α, as shown in FIG. 6A, the rotary stage 2 is accurately returned while confirming the rotation amount display device 2A by the nominal angle of the measured apex angle α. Next, the second rotation stage 10 is accurately rotated while confirming the second rotation amount display device 10A by the nominal angle of the measured apex angle β. Then, as shown in FIG. 6B, the normal direction of the C surface of the prism 22 faces the direction of the autocollimator 4, and the surface orientation of the C surface of the prism 22 can be observed by the autocollimator 4. Then, the amount of deviation between the reflection index of the C surface of the prism 22 and the reference index of the autocollimator 4 is measured, and this value becomes the error amount of the measured apex angle β.
[0029]
According to the present embodiment, in addition to the effects of the first embodiment, two apex angles having a common surface of the prism to be measured can be measured without replacing the prism, so that the measurement time can be shortened. .
[0030]
The technical idea of the following configuration is derived from the specific embodiment described above.
(Appendix)
(1) In the prism angle measuring method for measuring the apex angle of a prism, one of the two surfaces forming the measured apex angle of the prism is a reference surface and the other surface is the measured surface.
Align the normal direction of the reference surface of the holding jig that holds the prism with the direction of the autocollimator, hold the prism reference surface against the reference surface of the holding jig, and hold the prism reference surface and the holding jig Observe the interference fringe with the reference surface, rotate the holding jig by the nominal angle of the measured apex angle, measure the amount of deviation between the reflection index of the measured surface of the prism and the reference index of the autocollimator, and the amount of deviation A method for measuring the angle of a prism, characterized by:
Even prisms that are difficult to hold in shape can guarantee stable holding and improve measurement accuracy.
(2) A holding jig that holds and holds the reference surface of the prism, a rotation stage that rotates the holding jig by a predetermined angle, an autocollimator that measures the surface orientation of the surface to be measured of the prism, An prism fringe measuring device comprising interference fringe observation means for observing interference fringes between a reference surface and a reference surface of the holding jig.
The prism angle measurement method described in appendix (1) can be easily implemented, and the reliability of measurement accuracy can be increased.
(3) The prism angle measuring device according to appendix (2), wherein the reference surface of the holding jig that holds and holds the reference surface of the prism is mirror-finished.
In addition to the effect described in the supplementary note (2), the zero setting by the autocollimator is facilitated and interference fringes are reliably generated.
(4) The prism according to appendix (2) or (3), wherein a suction port that sucks the reference surface of the prism is provided on the reference surface of the holding jig that holds the reference surface of the prism against the reference surface. Angle measuring device.
In addition to the effects described in appendix (2) or (3), the prism can be easily held.
[0031]
【The invention's effect】
According to the optical component angle measuring method of the invention according to claim 1, the reference surface of the optical component is held against the reference surface of the holding jig, and the reference surface of the optical component and the reference surface of the holding jig are Since the measurement is performed by checking the holding state with the interference fringes, stable holding can be ensured and the measurement accuracy can be improved even for optical components that are difficult to hold in shape. According to the angle measurement apparatus for an optical component of the invention according to claim 2, the angle measurement method for the optical component of the invention according to claim 1 can be easily implemented, and the reliability of measurement accuracy can be improved. .
According to the angle measuring apparatus for an optical component of the invention of claim 3, in addition to the effect of the invention of claim 2, zero setting by an autocollimator is facilitated and interference fringes are reliably generated.
According to the optical component angle measuring apparatus of the invention of claim 4, in addition to the effect of the invention of claim 2 or claim 3, the optical component can be easily held.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an optical component angle measuring apparatus according to a first embodiment.
FIG. 2 is a process diagram illustrating a prism angle measuring method according to the first embodiment;
FIG. 3 is a schematic configuration diagram of an optical component angle measuring apparatus according to a second embodiment.
FIG. 4 is a view taken in the direction of arrow B in FIG. 3 of the second embodiment.
FIG. 5 is a perspective view of a prism to be measured according to a second embodiment.
6 is a process diagram illustrating a prism angle measurement method according to Embodiment 2. FIG.
FIG. 7 is a schematic configuration diagram showing a conventional surface orientation measuring apparatus.
[Explanation of symbols]
1 Holding jig 2 Rotating stage 3 Interference fringe observation camera 4 Autocollimator

Claims

In an optical component angle measuring method for measuring a measured apex angle formed by two surfaces of an optical component,
Directing a reference surface of a holding jig for holding the optical component to an autocollimator;
Observing the autocollimator and matching a reference index of the reference surface of the holding jig with a reference index of the autocollimator;
A step of holding a reference surface, which is one of the two surfaces of the optical component, against the reference surface of the holding jig;
Observing interference fringes between the reference surface of the holding jig and the reference surface of the optical component;
After confirming that the holding state of the optical component by the holding jig is good based on the observation result of the interference fringes, the holding jig is rotated by the nominal angle of the measured apex angle, and the two surfaces of the optical component are rotated. Measuring the reflection index of the surface to be measured, which is the other of the above, with the autocollimator,
An angle measurement method for an optical component, comprising: comparing the measured reflection index with a reference index of the autocollimator to obtain a deviation amount, and setting the deviation amount as an error amount of a measured vertex angle. .

In an optical component angle measuring apparatus for measuring a measured apex angle formed by two surfaces of an optical component,
A holding jig that holds and holds a reference surface that is one of the two surfaces of the optical component;
A rotating stage for rotating the holding jig by a predetermined angle;
An autocollimator that measures the surface orientation of the surface to be measured which is the other of the two surfaces of the optical component;
An angle measuring device for an optical component, comprising: observation means for observing interference fringes between a reference surface of the optical component and a reference surface of a holding jig applied with the reference surface.

The angle measuring device for an optical component according to claim 2, wherein a reference surface of the holding jig is mirror-finished.

4. The optical component angle measuring device according to claim 2, wherein a suction port for sucking the reference surface of the optical component is provided on the reference surface of the holding jig.