JP4768904B2

JP4768904B2 - Method for measuring physical quantity of optical element or optical system

Info

Publication number: JP4768904B2
Application number: JP2000236748A
Authority: JP
Inventors: 健志上原; 公彦西岡; 誠人安垣
Original assignee: Olympus Corp
Current assignee: Olympus Corp
Priority date: 2000-08-04
Filing date: 2000-08-04
Publication date: 2011-09-07
Anticipated expiration: 2020-08-04
Also published as: JP2002048673A

Description

【０００１】
【発明の属する技術分野】
本発明は、光学素子又は光学系の物理量測定方法に関するものである。
【０００２】
【従来の技術】
レンズ系の物理量（形状、曲率半径、面間隔、非球面係数、屈折率分布等を含む）の中、従来、一般的なレンズ系の偏心量の測定方法としては、オートコリメーション法が知られている。オートコリメーション法は、測定しようとする面の見かけ上の曲率中心、すなわち、被測定面と観察系との間に存在する別の面によって結像される被測定面の曲率中心の像の位置に指標を投影し、被検面による等倍の反射像をその指標の投影位置と同じ位置に生じさせる方法である。
【０００３】
上記の場合において、測定基準軸に関して全てのレンズ面に偏心がなければこの基準軸上に指標像が形成されるが、もし何れかのレンズ面に偏心が存在すれば、基準軸から基準軸に対して垂直な方向に離れた位置に反射像が形成されることになる。この反射像の基準軸からの振れ量Δは個々のレンズ面の偏心量εと関数関係があるので、各レンズ面についてその見かけの球心位置に投影した指標像の等倍反射像の振れ量Δを測定すれば、計算によってその測定基準軸に対する各レンズ面の偏心量を求めることができる。
【０００４】
図７は、偏心量（軸の傾き）εを持つ１被測定面５１により生じた振れ量Δを示した概略図である。図７のように、光源（指標）５２からの光束をコリメータレンズ５３で収束させて被測定面５１の測定基準軸上の球心位置に収束するように入射させる。光束の収束位置と被測定面５１の球心位置が一致する場合には、光束は被測定面５１に垂直入射することになる。しかし、光束の収束位置と被測定面５１の球心位置が一致していない（被測定面５１がε偏心している）と、光束は被測定面５１に斜入射することになる。ここで、垂直入射の場合は、被測定面５１で発生した反射光は入射時の光路を逆行し、光源（指標）５２と共役な位置に収束することになる。これに対し斜入射の場合は、被測定面５１で発生する反射光は入射時の光路からずれ、垂直入射した場合に収束した位置からΔずれた位置に収束する。
【０００５】
【発明が解決しようとする課題】
しかし、上記従来技術において、像面５４で測定された振れ量Δとレンズ面５１の偏心量εとの関係が比例するものであるとし、この比例関係の比例係数を近軸計算によって求めていたため、計算で得られた偏心量εの精度が低下することがあり得た。図７に示すコリメータレンズ５３の近軸計算により求めた倍率βを使用した場合、振れ量Δと被測定面５１の偏心量εとの関係式は被測定面５１の曲率半径をｒとすると、
Δ＝２βｒε ・・・（１）
となる。
【０００６】
本発明は従来技術のこのような問題に鑑みてなされたものであり、その目的は、光学素子の単体又は組み合わせからなる光学系の偏心をはじめとする物理量を表すパラメータを高い精度で求める手法を提供することである。
【０００７】
【課題を解決するための手段】
上記目的を達成する本発明の光学素子又は光学系の物理量測定方法は、被測定光学素子又は光学系に対して、前記被測定光学素子又は光学系の光軸とのなす角度をさまざまに変化させた光線を入射させ、
それぞれの角度に対して、前記被測定光学素子又は光学系から射出され、集光光学系により像面に結像した前記光線の特性を測定し、
前記それぞれの角度に対してリアルレイトレースを行い、
前記それぞれの角度の全てで、測定された前記光線の特性と、前記リアルレイトレースで求めた光線の特性との差が小さくなるようにリアルレイトレースにおける前記被測定光学素子又は光学系の偏心量又は前記被測定光学素子又は光学系のレンズ面の傾きとズレ量を変化させることで、少なくとも一つの最適化された前記被測定光学素子又は光学系の偏心量を求めることを特徴とする方法である。
【０００８】
この場合、前記光線の特性は、光線の像点位置、光線の像点位置における光強度分布、光線の波面収差等がある。
【０００９】
光線の像点位置、光線の像点位置における光強度分布の場合、前記物理量が前記被測定光学素子又は光学系の偏心量とすることができる。
また、光線の波面収差の場合、前記物理量が前記被測定光学素子又は光学系の屈折率分布とすることができる。
【００１０】
【発明の実施の形態】
以下、本発明の光学素子又は光学系の偏心測定方法の原理と実施例について説明する。
【００１１】
本発明は前記の問題点を解決するために、測定された振れ量Δから面の偏心量を算出する処理にリアルレイトレースを用いるものである。リアルレイトレースは実光線追跡とも呼ばれる。屈折及び反射の法則を厳密に計算して光線の位置、方向等を計算する方法である。光学系の偏心量、非球面を考慮した光線追跡が可能であり、計算機を用いた光学系の設計、評価等に広く利用されている。
【００１２】
リアルレイトレースの処理は、図１に示すように、光学系に入射する光線の位置ベクトルＰ₀、方向ベクトルＲ₀からの光学系の第１面（最初に光線と交わる面）との交点Ｐ₁を求め、交点位置での面の法線ベクトルＨ₁から光線の入射角θ_i1が決まる。入射側の媒質の屈折率ｎ₀と射出側の屈折率ｎ₁より、スネルの法則を用いて射出角θ_o1、射出光線の方向ベクトルＲ₁が求まる。第１面の交点の位置ベクトルＰ₁、射出光線の方向ベクトルＲ₁を第２面（次に光線と交わる面）への入射光線にして、次の面との交点、射出光線を繰り返し求めていくものである。
【００１３】
リアルレイトレースにより、光学系に入射した光束あるいは光線が光学系をいかに通り、射出されるかが計算でき、光束あるいは光線の像点位置、光束の重心位置、光束の状態（大きさ、形）、光線の方向・位置、光線の状態（強度、偏光状態）、又は、光束の広がり、ローカル近軸量（特開平１１−２８７９４７号）等の光学系の各種特性を算出することが可能である。
【００１４】
前記の発明が解決しようとする課題であげた振れ量Δは、例えば図６に示す光学系からなる測定機により測定される。振れ量Δは像点位置あるいは光束の重心位置を求める処理になる。物点（半導体レーザ）２０１から出た絞り中心を通る光線（主光線）を、測定用光学系２０２、ビームスプリッタ２０４を介して被測定レンズ２０３の各面の曲率中心に対して順々に投射し、この反射光を像面（ＣＣＤカメラ２０７の受光面）まで追跡し、像面（ＣＣＤカメラ２０７の受光面）での座標値を求める。ここでの絞り中心は、被検組上がりレンズ系（被測定レンズ２０３）の絞りの中心に限らず、被検面と光軸又はグローバル座標又はイメージローテータ２０５の回転中心軸との交点等を選んでもよい。また、光束の重心位置、形状は、物点（半導体レーザ）２０１から出た光線を複数本追跡し、光学系（測定用光学系）２０２からの射出光線をそれぞれ求める。射出光線の位置と方向、光線の強度等から像面（ＣＣＤカメラ２０７の受光面）での光束の重心位置、大きさ、形等を求める。
【００１５】
光線の強度、偏光状態は、光線の面への入射角、射出角、面の前後の屈折率によりエネルギー透過率、エネルギー反射率が求まり、各面の射出後のエネルギー透過率あるいはエネルギー反射率を掛け合わせることでその光線の強度が求まる。面にコーティング処理が施してある場合は、各層毎の特性行列を用いて透過率、反射率を算出できる。また、偏光状態も上記透過率、反射率を用いてジョーンズベクトルを追跡することで算出できる（「光学の原理」東海大学出版、「結晶光学」応用物理学会光学懇話会、「光学薄膜」共立出版参照）。
【００１６】
以下、本発明の光学素子又は光学系の偏心測定方法の１実施例を説明する。
【００１７】
図２に、偏心測定方法を実施する処理装置のブロック図を示す。本装置は、上記のような光束の像の状態又は光線の状態を測定する測定機８、表示装置２、キーボード等の入力装置３、磁気ディスク等の記憶装置４、プリンター等６、及び、それらを統括処理し、かつ、処理を行う演算処理装置１よりなる。この他に、外部の光学素子測定機９、光学系設計装置１０等とデータや処理方法等をやりとりするためのＬＡＮ７に接続されており、フロッピーディスクや光磁気ディスク等の外部媒体５との入出力機構も備えている。
【００１８】
測定機８からは、前記のように、被検光学系から射出される光束の像の状態、又は、光線の状態の測定データの他、測定光学系に関する面間隔データ、移動量等も送られる。
【００１９】
光学素子測定機９は、光学素子の面形状、面間隔、媒質の屈折率、コーティング膜厚等の各種測定機の集合であり、この測定機９からは、被検光学系、測定光学系のｒ、ｄ、ｎの測定データ、あるいは、コーティングデータ、製造誤差データ等が送られる。ここで、ｒ：曲率又は曲率半径（非球面の場合は面の方程式）、ｄ：面間隔、ｎ：媒質の屈折率、コーティングデータ：各膜の複素屈折率、膜厚である。
【００２０】
光学系設計装置１０は、光学系を設計する装置である。この装置からは、被検光学系、測定光学系のｒ、ｄ、ｎ等の設計値データ等が送られる。また、本発明の方法より求めた偏心データを取り込み、設計に反映し、又は、光学系を評価することが可能となっている。
【００２１】
図２の装置で図３に示す処理を行う。すなわち、Ｓｔｅｐ１では、図２の入力装置３、記憶装置４、外部媒体５、測定機８、光学素子測定機９、光学系設計装置１０からのＳｔｅｐ２の偏心量算出処理に用いる被検光学系、測定光学系のｒ、ｄ（測定光学系における測定のための面間隔移動量も含む）、ｎデータ、コーティングデータ、製造誤差データ、被検光学系から射出される光束の像の状態データ、又は、光線の状態の測定データ、既に分かっている偏心データ、求める偏心の種類、範囲等を必要に応じて入力する。
【００２２】
Ｓｔｅｐ２では、Ｓｔｅｐ１で入力された各種データを基に、図２の演算装置１によりリアルレイトレースを行い、求める偏心量を算出する。
【００２３】
Ｓｔｅｐ３では、求めた偏心量を図２の表示装置２、記憶装置４、外部媒体５、プリンタ６に出力する。又は、測定機８、光学素子測定機９、光学系設計装置１０等にデータ転送する。
【００２４】
次に、図３の偏心量算出処理Ｓｔｅｐ２に相当する部分の処理を、図４の連立方程式の解法にリアルレイトレースを用いた例で説明を行う。従来のオートコリメーション法を用いた偏心測定に当てはめると、連立方程式は例えば以下のようにおける。
【００２５】
評価関数をＦ_i（ｘ₁，ｘ₂，ｘ₃，・・・，ｘ_n）、ｉ＝１，２，３・・・ｎ：例えば像点位置とする。像点位置は、リアルレイトレースを用いれば、例えば図８に示すように、物点から光学系に絞り中心を通る光線を入射させ、その光線が射出する光線と像面との交点として算出できる。また、評価関数として扱えるものは、像点位置のほかに、例えば図９（ａ）に示すような、物点から光学系に入射した光束（複数本の光線）が光学系から射出される光束（複数本の光線）のある断面（図９（ｂ）、（ｃ））における重心位置、光束の広がり、又は、波動光学的点像強度分布、光線の状態等、測定可能なものでリアルレイトレースを行うことにより算出できるものであれば全て扱える。
【００２６】
変数ｘ_j（１，２，３，・・・ｍ）、ｊ＝１，２，３，・・・ｍ：例えば図１０に示した面あるいは単レンズ、レンズ群における偏心量とする。図１０（ａ）は、面の偏心量の定義を示しており、基準軸上の面の中心軸の基準軸となすｘ−ｚ面内の傾きε_x、ｙ−ｚ面内の傾きε_yで偏心量を表している。図１０（ｂ）は、レンズの偏心量の定義を示しており、レンズの中心軸と基準軸となすｘ−ｚ面内の傾きε_x、ｙ−ｚ面内の傾きε_yと、レンズ第１面の中心の基準軸からのｘ−ｚ面内のズレ量δ_x、ｙ−ｚ面内のズレ量δ_yとで偏心量を表している。図１０（ｃ）は、レンズ群の偏心量の定義を示しており、図１０（ｂ）と同様である。図１０（ｄ）は、図１０（ｂ）とは別のレンズの偏心量の定義を示しており、任意の点Ｐ（Ｘ，Ｙ）を中心に回転しているとして、その中心軸の基準軸となすｘ−ｚ面内の傾きε_x、ｙ−ｚ面内の傾きε_yで偏心量を表している。
【００２７】
ここで、ａ_ij＝∂Ｆ_i／∂ｘ_j（偏微分）、初期の評価関数値をＦ_i0、初期の変数値をｘ_j0とすると、
Ｆ_i≒Ｆ_i0＋Σａ_ij（ｘ_j−ｘ_j0）・・・（２）
となる。このＦ_iが測定結果である像面位置Ｆ_imに十分近づいた状態になる偏心量（変数ｘ_j）が算出できればよい。
【００２８】
Ｓｔｅｐ４では、偏心量（変数）が初期状態（ｘ_j0）での像点位置（評価関数Ｆ_i0）をリアルレイトレースで求める。
【００２９】
Ｓｔｅｐ５からＳｔｅｐ７では、差分によりａ_ijを成分とする行列Ａ_ijを求める。一つの偏心量（変数ｘ_i）を微小に変化させた状態でリアルレイトレースを行い、一つの偏心量の単位変化量に対する像点位置（評価関数Ｆ_i）の変化量∂Ｆ_i／∂ｘ_jを求める。
【００３０】
Ｓｔｅｐ８では、最適化処理により偏心量（変数ｘ_i）の変化量と変化後の像点位置（評価関数Ｆ_i）を求める。
【００３１】
Ｓｔｅｐ９では、最適化により求まった像点位置（評価関数Ｆ_i）と測定結果である像面位置Ｆ_imを比較し、十分に近い状態かどうか評価する。もし、十分な状態でない場合、Ｓｔｅｐ１０で最適化後の像点位置（評価関数Ｆ_i）、偏心量（変数ｘ_j）をそれぞれ初期状態（評価関数_i0、変数ｘ_j0）に置き換えて、Ｓｔｅｐ５の処理に戻る。Ｓｔｅｐ９で十分な状態である評価した場合は、処理を終了する。
【００３２】
以上の処理において、従来のオートコリメーション法では、被検光学系からの反射光を測定する。被検光学系の前方から光束を入射し、測定面からの反射光の結像位置（像点位置又は重心位置）を測定する。測定した位置を評価関数とし、被検面の偏心量を変数として、以上の処理を行うことにより、被検面の量を求める。求まった偏心量は光学系に加え、光学系のデータとして次の面の偏心量算出処理を行う。前面から後面に１面ずつ順に処理を行っていく。その処理を図示すると図５のようになる。
【００３３】
また、オートコリメーション法とは別の方法として、評価関数として扱える像点位置、光束の重心位置、光束の広がり、光線の状態等を一つあるいは複数測定し、評価関数とする方法もある。測定時に光が通った範囲の一つ以上の被検面、単レンズ、群レンズの偏心量を同時に変数にして最適化処理を行うことにより、変数にした一つ以上の被検面、単レンズ、群レンズの偏心量を一度に算出することが可能である。
【００３４】
また、従来のオートコリメーション法で用いている近軸量の代わりに、ローカル近軸量を用いることもできる。図７における光源５２から像面５４に至る任意の基準光線を設定し、基準光線の近傍を伝播する微小光束の広がりを全系にわたって計算することにより、偏心量を考慮した非対称光学系での基準光線近傍におけるローカル近軸量が得られる。ローカル近軸量として得られる情報には、結像位置、結像方位、焦線方位、倍率、焦点距離、瞳位置、主点位置、節点位置、非点収差、像面歪曲、照度等があり（特開平１１−２８７９４７号）、式（１）のβの代わりにローカル近軸量の倍率を採用することにより、被検光学系の偏心量の精度を向上することができる。
【００３５】
また、上記リアルレイトレースを行う光学系の実際の面の曲率半径ｒ、面間隔ｄ、屈折率ｎ等は製造誤差等により意図した光学系とは異なるものになっていることもある。リアルレイトレースを行う光学系のデータを、図２の光学素子測定機９等で測定された面の曲率半径ｒ、面間隔ｄ、屈折率ｎ等のデータと置換、又は、図２の光学素子測定機９等で測定された曲率半径ｒ、面間隔ｄ、屈折率ｎ等の製造誤差データ、又は、曲率半径ｒ、面間隔ｄ、屈折率ｎ等の公差量等のデータを、光学系の面の曲率半径ｒ、面間隔ｄ、屈折率ｎ等に加える。これを光学系のデータとして扱い、リアルレイトレースを行うことで、実際により近い追跡結果が算出され、求められる偏心量の精度を向上することができる。
【００３６】
また、オートコリメーション法では、被測定面の球心位置に収束するように光束を入射させる。これを実現するためには、被測定面に応じて測定機光学系内部を動かして測定を行う必要がある場合もある。上記リアルレイトレースを行う光学系に、被測定面に応じた測定機光学系内部の変動量を測定して加える。これを光学系データとして扱い、リアルレイトレースを行うことにより、実際により近い追跡結果が算出され、求められる偏心量の精度を向上することができる。
【００３７】
また、リアルレイトレースを用いて上記偏心測定、評価、解析を行う光学系には、カメラ、内視鏡、顕微鏡等のズームレンズ等がある。
【００３８】
次に、リアルレイトレースを用いて光学系あるいは光学素子の偏心測定、評価、解析を行う実施例を図１１と図１３に示す。
【００３９】
図１１は、特開平７−１２０２１８号及び特開平９−２２２３８０号に示されている斜入射法を用いた非球面偏心測定機にリアルレイトレースを応用し、精度を向上させた例を示す図である。図１１（ａ）は、非球面１２０の光軸付近に光束を入射させた状態、図１１（ｂ）は、非球面１２０の周辺部に光束を斜めに入射させた状態を示している。何れの場合も、非球面１２０の表面で反射した光束は、ミラー１１１、投影レンズ１０３、ビームスプリッタ１１５、顕微鏡対物レンズ１０５、三角プリズム１３４、ズームレンズ１０６と進み、ＣＣＤカメラ１０７に輝点となって結像する。非球面１２０を回転させると、ＣＣＤカメラ１０７上の反射してきた光束の輝点は曲線を描き、ＣＣＤカメラ１０７上で回るが、この輝点の軌跡を解析することで被検非球面レンズ１２１の非球面１２０の偏心δｒと傾きεｒをその方位角εθ、δθと共に求めることができる。
【００４０】
ところが、上述の２件の特許では、軌跡を解析するのに近軸計算及びローカル曲率に基づく近軸計算を用いていたため、必ずしも精度が良いとは言えなかった。
【００４１】
そこで、本発明では、偏心測定機１４１の光学系の全ての面の光学設計データ、つまり、各面の
ｒ：曲率半径（非球面の場合は面の方程式）
ｄ：次の面までの距離
ｎ：媒質の屈折率
を計算機１５０に入力しておき、被検非球面のεｒ、δｒ並びにεｒ、δｒの方位角εθ、δθを変数としてＣＣＤカメラ１０７で観測した被検非球面レンズ１２１を回転させたときの軌跡にリアルレイトレースした輝点の軌跡が一致するようなεｒ、δｒ、εθ、δθの最適値を求める。
【００４２】
このようにすれば、近軸光線での解析よりも精度良くεｒ、δｒ、εθ、δθを求めることかできる。
【００４３】
なお、図中の符号１４９はＣＣＤカメラ１０７の出力を処理する信号処理回路であり、符号１５１はＴＶモニターである。
【００４４】
ε_x＝εｒ・ｃｏｓεθ
ε_y＝εｒ・ｓｉｎεθ
δ_x＝δｒ・ｃｏｓδθ
δ_y＝δｒ・ｓｉｎδθ
であるから、εｒ、δｒ、εθ、δθの代わりに偏心量の成分ε_x、ε_y、δ_x、δ_yを求めてもよい。
【００４５】
図１２に、上記εｒ、δｒ、εθ、δθの定義を示す。
【００４６】
次に、図１３はリアルレイトレースを用いた心出顕微鏡１６０の例を示す図であり、この心出顕微鏡１６０は、１枚のレンズの偏心測定、レンズの１面の偏心測定、複数のレンズの接合のために、それぞれのレンズの偏心を調べつつ接合するときに用いられる。
【００４７】
この心出顕微鏡１６０において、光源１６１から出た光は、ターゲットのピンホール１６２、採光レンズ１６３、ビームスプリッタ（ハーフプリズム）１１５を通り、被検面１６４に入射する。被検面１６４で反射した光束は、ビームスプリッタ（ハーフプリズム）１１５、変倍系１７１を有する光学系１０２、ハーフミラー１６７、結像レンズ１６６と進み、ＣＣＤカメラ１０７に輝点となって結像する。被検レンズ１６５を回転させたとき、ＣＣＤカメラ１０７上の輝点の位置又は軌跡から被検面１６４の偏心を求めることができる。ＣＣＤカメラ１０７の代わりに、焦点板１６８上の輝点の位置又は軌跡から、接眼レンズ１６９を介して眼１７０で観察して被検面１６４の偏心を求めてもよい。
【００４８】
ここで、ピンホール１６２の採光レンズ１６３による像は、被検面１６４の球心にできるのではなく、その球心から外れた位置にできるものでもよく、図１３はそのような場合を図示している。それを不等倍結像の状態という。同様にして、被検面１６４の下方の面１７２、１７３、１７４の偏心を求めることができる。
【００４９】
輝点の位置又は軌跡から被検面び偏心を求めるには、従来、近軸理論で解析していた。しかし、心出顕微鏡１６０の光学系の収差（特に歪曲収差）のため、精度がやや悪かった。そこで、本発明では、心出顕微鏡１６０の光学系の各面の
ｒ：曲率半径（非球面の場合は面の方程式）
ｄ：次の面までの距離
ｎ：媒質の屈折率
を計算機１５０に入力しておき、ＣＣＤカメラ１０７上の輝点の位置又は軌跡にリアルレイトレースした輝点の位置が略一致するような被検面１６４の偏心を求めることで、被検面１６４の偏心を知ることができる。
【００５０】
次に、複数面を有するレンズ系に非球面で構成されたレンズ面が含まれている場合の偏心測定の実施例を示す。非球面は一義的に決まる非球面軸が存在するため、例えばレンズ面の傾きεとズレ量δの偏心を表すパラメータが必要となる。偏心を表すパラメータは、光軸と直交し、かつ、それぞれが直交する２方向の成分（ε_x，ε_y）、（δ_x，δ_y）で表してもよい。また、図１２に非球面の偏心の定義を示すように、極座標（εｒ，εθ）、（δｒ，δθ）等でもよい。これらの偏心を表わすパラメータを求めるには以下のようにすればよい。
【００５１】
一般的に、測定しようとするレンズ面が非球面であるとき、この面に傾きεがある場合の指標の反射像の光強度分布と、この面にズレ量δがある場合の指標の反射像の光強度分布は異なるため、測定された指標の反射像の光強度分布を目標値として、例えば被測定面の傾きεとズレ量δを変数にして、リアルレイトレース又は近軸光線追跡を行い、傾きεとズレ量δを最適化することで、偏心を表すパラメータを求めることができる。
【００５２】
上記の光強度分布は、検出器で検出された光の強度分布の形状、及び、幾何光学的あるいは波動光学的に計算された光の強度分布を意味する。
【００５３】
また、被検光学系の評価を行うためには、偏心を表すパラメータの中、必要とされる少なくとも一つのパラメータを求めればよい。
【００５４】
また、図７において、光源５２から射出する光束の中一部の光線だけを被検光学系に入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面から反射する光線の位置を検出し、それぞれの状態に対してリアルレイトレース又は近軸光線追跡を行い、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるよう、傾きεとズレ量δを最適化することでも、偏心を表すパラメータを求めることができる。
【００５５】
また、図１４に示すように、マイクロレンズアレイ６２で点光源像群を作り、それを投影レンズ６３で被検面６１に投影し、被検面６１で反射若しくは屈折した光をハーフミラー６４を介して（被検面６１で反射させる場合）撮像素子６５で検出し、図１５に例示するような各点光源の像を得て、各点光源像の位置を目標としてリアルレイトレース又は近軸光線追跡を行い、全ての状態において測定された点光源像の位置と光線追跡で求めた点光源像の位置との差が小さくなるよう、傾きεとズレ量δを最適化することでも、偏心を表すパラメータを求めることができる。
【００５６】
また、図１６に示すように、シャックハルトマン法の応用例として、被検光学素子又は光学系７１を透過した光をコリメートレンズ７２を介してマイクロレンズアレイ７３に導いて点像群を作り、リレーレンズ７４を経てその点像群を撮像素子７５で検出し、各点像の位置を目標としてリアルレイトレース又は近軸光線追跡を行い、全ての状態において測定された点光源像の位置と光線追跡で求めた点光源像の位置との差が小さくなるよう、各面の傾きεとズレ量δを最適化することでも、偏心を表すパラメータを求めることができる。
【００５７】
また、測定しようとする非球面を含むレンズ単体において、レンズの前面と後面との間の面間偏心ε_Lが、面間偏心測定機等で得られている場合には、前面及び後面単体での軸の光軸に対する傾きε（それぞれε₁ 、ε₂ ）とズレ量δ（それぞれδ₁ 、δ₂ ）と、指標の反射像の測定から得られた前面の傾き量ε₁'、後面の傾き量ε₂'、及び、ε_L、及び、前面の近軸曲率半径Ｒ₁、後面の近軸曲率半径Ｒ₂、レンズ厚Ｔから、前面と後面の傾きεとズレ量δを、以下のように計算することができる。なお、偏心を表するパラメータε₁ 、ε₂ 、ε₁'、ε₂'、ε_L、δ₁ 、δ₂ は、ｘ、ｙそれぞれの成分を表している。
【００５８】
ε₁'＝ε₁ ＋δ₁ ／Ｒ₁ ・・・（３）
ε₂'＝ε₂＋δ₂／Ｒ₂ ・・・（４）
ε₂ ＝ε₁ ＋ε_L ・・・（５）
δ₂ ＝δ₁ ＋Ｔε₁ ・・・（６）
式（３）〜（６）から、
δ₁ ＝（Ｒ₁Ｒ₂＋Ｒ₁Ｔ）ε₁'／（Ｒ₂−Ｒ₁＋Ｔ）
−Ｒ₁Ｒ₂（ε₂'−ε_L）／（Ｒ₂−Ｒ₁＋Ｔ）・・・（７）
δ₂ ＝Ｒ₁Ｒ₂ε₁'／（Ｒ₂−Ｒ₁＋Ｔ）
−（Ｒ₁Ｒ₂−Ｒ₂Ｔ）（ε₂'−ε_L）／（Ｒ₂−Ｒ₁＋Ｔ）・・・（８）
ε₁ ＝−Ｒ₁ε₁'／（Ｒ₂−Ｒ₁＋Ｔ）
＋Ｒ₂（ε₂'−ε_L）／（Ｒ₂−Ｒ₁＋Ｔ）・・・（９）
ε₂＝ε₁'＋ε_L ・・・（10）
以上の計算は、光学系の近軸的な性質を基にした計算であり、式（７）〜（１０）の方程式で偏心量を求めることができるし、リアルレイトレースで被検光学系の各面の偏心を計算する場合に、非球面を含むレンズの両面の面間偏心を束縛条件として計算することもできる。
【００５９】
なお、言うまでもなく、式（７）〜（１０）と数学的に同値な方程式（例えば、極座標に変換したもの）を用いてももちろんよい。
【００６０】
ところで、複数面を有するレンズ系の各面の測定をオートコリメーション法（図７）を用いて行う場合、測定しようとする面５１の見かけ上の曲率中心、すなわち、被測定面５１と観察系との間に存在する別の面によって結像される被測定面５１の曲率中心の像の位置に、指標若しくは光源像を投影し、被検面５１による等倍の反射像を、その指標若しくは光源像の投影位置と同じ位置に生じさせたときに、測定しようとするレンズ面以外から反射された指標像若しくは光源像が、測定しようとするレンズ面５１による指標若しくは光源像の近傍に生じることが有り得る。この場合には、どちらが測定しようとするレンズ面による指標像若しくは光源像かの区別が困難である。
【００６１】
そこで、このような場合には、測定しようとする面の見かけ上の曲率中心、すなわち、被測定面５１と観察系との間に存在する別の面によって結像される被測定面５１の曲率中心の像の位置から光軸に沿った方向にずらした位置に指標若しくは光源像を投影する。その様子を図１７に示す。図７の光源５２若しくはコリメータレンズ５３の位置を光軸に沿ってずらせた場合に相当する。このとき、指標若しくは光源像を投影した位置とのその反射像の位置は異なり、倍率も等倍ではなくなる。
【００６２】
また、上記した測定しようとするレンズ面５１以外から反射される指標の像若しくは光源像の位置もずれ、一般に測定しようとするレンズ面５１による反射像の位置のずれ量と測定しようとするレンズ面以外からの反射像の位置ずれ量は異なるため、測定しようとするレンズ面５１から反射される指標の像若しくは光源像のずれ量を計算で求めておき、この位置に結像される指標の像若しくは光源像の反射像を検出するようにすることで、測定しようとするレンズ面５１による指標像若しくは光源像を区別することができる。また、投影する指標若しくは光源像に対する指標若しくは光源像の反射像の倍率の絶対値を１より大きくすることにより、等倍で結像する場合よりも偏心測定精度を向上させることができる。また、被検面で反射した光線の代わりに被検面で屈折した光線を検出する方法でもよい。
【００６３】
次に、リアルレイトレースを用いて光学素子の屈折率分布測定・評価・解析を行う実施例を、図１８を用いて説明する。
【００６４】
Ｈｅ−Ｎｅレーザー８１からのレーザー光をビームスプリッタ８２で２つの光路に分割し、一方を被検光学素子８３に入射させ、残る一方をその被検光学素子８３の設計値通りの光学性能を持つ基準光学系８４に入射させ、双方の光学系を透過した光束をビームスプリッタ８５で合成し、スクリーン８６上に干渉縞が発生するように投影する。干渉縞の像はテレビカメラで取り込み、計算機に入力して縞の解析を行い、スクリーン８６上の光束内における位相差分布を求める。
【００６５】
このような装置により測定される位相差分布は、被検光学素子８３に平行光束を入射させた場合の、射出瞳面における波面収差に該当する。
【００６６】
一般に、屈折率分布は、
ｎ（ｒ）＝ｎ₀＋ｎ₂ｒ²＋ｎ₄ｒ⁴＋ｎ₆ｒ⁶＋・・・・・（11）
の形で表せられる。
【００６７】
被検光学素子８３の光軸方向の厚さが十分に小さくなく、被検光学素子８３内での光線の屈曲が無視できない場合には、リアルレイトレースによって計算した波面収差が、測定した波面収差に等しくなるように、式（１１）の係数ｎ₂、ｎ₄、ｎ₆を変数として屈折率分布の最適化を行う。
【００６８】
この場合、被検光学素子８３に平行光を入射させた場合の射出波面の、基準光学系８４に平行光を入射させた場合の射出波面からのズレを測定していると考えられ、基準光学系８４の収差が無視できる程小さければ、射出波面は球面となるため、被検光学素子８３に平行光を入射させた場合の射出波面の、基準光学系８４に平行光を入射させた場合の射出波面からのズレは、被検光学素子８３に平行光を入射させた場合の波面収差と一致する。
【００６９】
そのため、屈折率分布形状を式（１１）で定義した媒質の各屈折率分布係数を、初期状態を設計値とする変数として、リアルレイトレースを行い、その射出波面、すなわち波面収差を、測定値にフィッティングさせるように最適化を行えば、各係数が得られる。
【００７０】
以上の本発明の光学素子又は光学系の偏心測定方法等は、次のように構成することができる。
【００７１】
〔１〕被測定光学素子又は光学系に光を入射し、その光学素子又は光学系から射出される光の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の偏心量を求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７２】
〔２〕被測定光学素子又は光学系に光線を入射し、その光学素子又は光学系から射出される光線の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の偏心量を求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７３】
〔３〕被測定光学素子又は光学系に光束を入射し、その光学素子又は光学系から射出される光束の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の偏心量を求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７４】
〔４〕被検光学素子又は光学系中の被検面に光を入射させる手段と、その光が被検光学素子又は光学系中の被検面より反射又は屈折した光を検出する光検出手段と、前記被検面で反射又は屈折された光を前記光検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の偏心を測定する偏心測定機において、前記光学素子又は光学系中の被測定面より前記光検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光検出手段における光の状態が、測定された光の状態と等しくなるような被検面の偏心量を計算で求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７５】
〔５〕被検光学素子又は光学系中の被検面に光線を入射させる手段と、その光線が被検光学素子又は光学系中の被検面より反射又は屈折した光線を検出する光線検出手段と、前記被検面で反射又は屈折された光線を前記光線検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の偏心を測定する偏心測定機において、前記光学素子又は光学系中の被測定面より前記光線検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光線検出手段における光線の状態が、測定された光線の状態と等しくなるような被検面の偏心量を計算で求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７６】
〔６〕被検光学素子又は光学系中の被検面に光束を入射させる手段と、その光束が被検光学素子又は光学系中の被検面より反射又は屈折した光束を検出する光束検出手段と、前記被検面で反射又は屈折された光束を前記光束検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の偏心を測定する偏心測定機において、前記光学素子又は光学系中の被測定面より前記光束検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光束検出手段における光束の状態が、測定された光束の状態と等しくなるような被検面の偏心量を計算で求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７７】
〔７〕被測定光学素子又は光学系あるいは測定機の光学素子又は光学系の製造誤差を含んだ光学素子又は光学系でリアルレイトレースを行うことを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７８】
〔８〕測定機の光学素子又は光学系内部の変動量を測定し、変動量を考慮した光学素子又は光学系でリアルレイトレースを行うことを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００７９】
〔９〕光学素子又は光学系の前面から１面ずつ測定して偏心量を求め、次の面では前に求めた偏心量を含んだ光学素子又は光学系でリアルレイトレースを行い、その面の偏心量を求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８０】
〔１０〕前記測定値を目標値、求める面の偏心量を未知数とした方程式の解法処理をリアルレイトレースを用いて行うことを特徴とする上記１から３の何れか１項記載の光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８１】
〔１１〕前記測定値を目標値、任意の位置又は任意の軸を基準とした複数の面あるいはレンズ群の偏心量を未知数とした方程式の解法処理をリアルレイトレースを用いて行うことを特徴とする上記１から３の何れか１項記載の光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８２】
〔１２〕前記未知数の算出に、最適化処理を用いることを特徴とする上記１０又は１１記載の光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８３】
〔１３〕波動光学的点像強度分布を評価関数とすることを特徴とする上記１２記載の光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８４】
〔１４〕光束の像を測定する場合の結像関係が等倍結像あるいは不等倍結像の何れかを用いることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８５】
〔１５〕ローカル近軸量を用いたオートコリメーション法又は不等倍像法により偏心量を求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８６】
〔１６〕測定された指標の反射像の光強度分布又は位置を目標値として、非球面である被測定面の偏心量を変数にして光線追跡を行い、偏心量を最適化することで少なくとも一つの偏心量を求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８７】
〔１７〕測定された指標の反対像の光強度分布又は位置を目標値として、非球面である被測定面の傾きと偏り量を変数にして光線追跡を行い、傾きと偏り量を最適化することで、傾きと偏り量のそれぞれの要素の中少なくとも一つの偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８８】
〔１８〕測定された指標の反射像の光強度分布又は位置を目標値として、非球面である被測定面の光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量を変数にして光線追跡を行い、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量を最適化することで、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量の少なくとも一つの偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００８９】
〔１９〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように偏心量を最適化することで、少なくとも一つの偏心量を求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９０】
〔２０〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように傾きと偏り量を最適化することで、傾きと偏り量の少なくとも一つの偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９１】
〔２１〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量を最適化することで、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量の少なくとも一つの偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９２】
〔２２〕光学系中若しくは単体の非球面レンズにおいて、レンズの前面と後面との間の既知の面間偏心ε_Lを用い、指標の反射像の測定から得られた前面の傾き量ε₁'、後面の傾き量ε₂'、及び、ε_L、及び、前面の近軸曲率半径Ｒ₁、後面の近軸曲率半径Ｒ₂、レンズ厚Ｔから、以下の式若しくは数学的に同値の式により前面と後面の傾きε₁ とε₂、偏り量δ₁ とδ₂ を計算することを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９３】
δ₁ ＝（Ｒ₁Ｒ₂＋Ｒ₁Ｔ）ε₁'／（Ｒ₂−Ｒ₁＋Ｔ）
−Ｒ₁Ｒ₂（ε₂'−ε_L）／（Ｒ₂−Ｒ₁＋Ｔ）・・・（７）
δ₂ ＝Ｒ₁Ｒ₂ε₁'／（Ｒ₂−Ｒ₁＋Ｔ）
−（Ｒ₁Ｒ₂−Ｒ₂Ｔ）（ε₂'−ε_L）／（Ｒ₂−Ｒ₁＋Ｔ）・・・（８）
ε₁ ＝−Ｒ₁ε₁'／（Ｒ₂−Ｒ₁＋Ｔ）
＋Ｒ₂（ε₂'−ε_L）／（Ｒ₂−Ｒ₁＋Ｔ）・・・（９）
ε₂＝ε₁'＋ε_L ・・・（10）
〔２３〕光学系中若しくは単体の球面若しくは非球面レンズにおいて、レンズの前面と後面との間の既知の面間偏心を用いてその面間偏心を束縛条件とし、リアルレイトレースを用いて偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９４】
〔２４〕測定しようとする面のみかけ上の曲率中心、すなわち、被測定面と偏心測定機の観察系との間に存在する別の面によって結像される被測定面の曲率中心の像の位置から光軸に沿った方向にずらした位置に指標を投影し、測定しようとするレンズ面から反射される指標の像のずれ量を計算で求めておき、この位置に結像される指標の像の反射像を検出することを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９５】
〔２５〕投影する指標に対する指標の反射像の倍率の絶対値が１より大きくすることを特徴とする上記２４記載の光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９６】
〔２６〕リアルレイトレースを用いることを特徴とする上記２４又は２５記載の光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９７】
〔２７〕光源と、光源からの光を複数の点光源群像に分割する手段と、前記点光源像群を被検面近傍に投影する手段と、前記被検面で反射ないし屈折した前記点光源像群を検出する検出手段と、前記被検面で反射ないし屈折した前記点光源像群を前記検出手段に導く手段とを備え、検出された点光源像群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９８】
〔２８〕光学素子若しくは光学系を透過した光を複数の点光源像群に分割する手段と、前記点光源像群を検出する検出手段と、前記点光源像群を前記検出手段に導く手段とを備え、検出された点光源像群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【００９９】
〔２９〕光源と、光源からの光を複数の光束群に分割する手段と、前記光束群を被検面近傍に投影する手段と、前記被検面で反射ないし屈折した前記光束群を検出する検出手段と、前記被検面で反射ないし屈折した前記光束群を前記検出手段に導く手段とを備え、検出された光束群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【０１００】
〔３０〕光学素子若しくは光学系を透過した光を複数の光束群に分割する手段と、前記光束群を検出する検出手段と、前記光束群を前記検出手段に導く手段とを備え、検出された光束群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の偏心を表すパラメータを求めることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【０１０１】
〔３１〕カメラ、内視鏡、顕微鏡等のズームレンズの光学系を対象にしていることを特徴とする上記１から３０の何れか１項記載の光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【０１０２】
〔３２〕上記１から３０の何れか１項記載の処理方法を機械可読な形で記録したことを特徴とする記憶媒体。
【０１０３】
〔３３〕上記１から３０の何れか１項記載の処理方法を用いていることを特徴とする偏心測定処理装置。
【０１０４】
〔３４〕測定機を制御するコンピュータとリアルレイトレースを行うコンピュータとが同一であることを特徴とする光学素子又は光学系の偏心測定方法又は測定機又は測定されたもの。
【０１０５】
〔３５〕被測定光学素子又は光学系に光を入射し、その光学素子又は光学系から射出される光の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の物理量を求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１０６】
〔３６〕被測定光学素子又は光学系に光線を入射し、その光学素子又は光学系から射出される光線の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の物理量を求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１０７】
〔３７〕被測定光学素子又は光学系に光束を入射し、その光学素子又は光学系から射出される光束の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の物理量を求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１０８】
〔３８〕被検光学素子又は光学系中の被検面に光を入射させる手段と、その光が被検光学素子又は光学系中の被検面より反射又は屈折した光を検出する光検出手段と、前記被検面で反射又は屈折された光を前記光検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の物理量を測定する物理量測定機において、前記光学素子又は光学系中の被測定面より前記光検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光検出手段における光の状態が、測定された光の状態と等しくなるような被検面の物理量を計算で求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１０９】
〔３９〕被検光学素子又は光学系中の被検面に光線を入射させる手段と、その光線が被検光学素子又は光学系中の被検面より反射又は屈折した光線を検出する光線検出手段と、前記被検面で反射又は屈折された光線を前記光線検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の物理量を測定する物理量測定機において、前記光学素子又は光学系中の被測定面より前記光線検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光線検出手段における光線の状態が、測定された光線の状態と等しくなるような被検面の物理量を計算で求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１０】
〔４０〕被検光学素子又は光学系中の被検面に光束を入射させる手段と、その光束が被検光学素子又は光学系中の被検面より反射又は屈折した光束を検出する光束検出手段と、前記被検面で反射又は屈折された光束を前記光束検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の物理量を測定する物理量測定機において、前記光学素子又は光学系中の被測定面より前記光束検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光束検出手段における光束の状態が、測定された光束の状態と等しくなるような被検面の物理量を計算で求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１１】
〔４１〕被測定光学素子又は光学系あるいは測定機の光学素子又は光学系の製造誤差を含んだ光学素子又は光学系でリアルレイトレースを行うことを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１２】
〔４２〕測定機の光学素子又は光学系内部の変動量を測定し、変動量を考慮した光学素子又は光学系でリアルレイトレースを行うことを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１３】
〔４３〕光学素子又は光学系の前面から１面ずつ測定して物理量を求め、次の面では前に求めた物理量を含んだ光学素子又は光学系でリアルレイトレースを行い、その面の物理量を求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１４】
〔４４〕前記測定値を目標値、求める面の物理量を未知数とした方程式の解法処理をリアルレイトレースを用いて行うことを特徴とする上記３５から３７の何れか１項記載の光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１５】
〔４５〕前記測定値を目標値、任意の位置又は任意の軸を基準とした複数の面あるいはレンズ群の物理量を未知数とした方程式の解法処理をリアルレイトレースを用いて行うことを特徴とする上記３５から３７の何れか１項記載の光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１６】
〔４６〕前記未知数の算出に、最適化処理を用いることを特徴とする上記４４又は４５記載の光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１７】
〔４７〕波動光学的点像強度分布を評価関数とすることを特徴とする上記４６記載の光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１８】
〔４８〕光束の像を測定する場合の結像関係が等倍結像あるいは不等倍結像の何れかを用いることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１１９】
〔４９〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように物理量を最適化することで、少なくとも一つの物理量を求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２０】
〔５０〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように傾きと偏り量を最適化することで、傾きと偏り量の少なくとも一つの物理量を表すパラメータを求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２１】
〔５１〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量を最適化することで、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量の少なくとも一つの物理量を表すパラメータを求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２２】
〔５２〕測定しようとする面のみかけ上の曲率中心、すなわち、被測定面と物理量測定機の観察系との間に存在する別の面によって結像される被測定面の曲率中心の像の位置から光軸に沿った方向にずらした位置に指標を投影し、測定しようとするレンズ面から反射される指標の像のずれ量を計算で求めておき、この位置に結像される指標の像の反射像を検出することを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２３】
〔５３〕投影する指標に対する指標の反射像の倍率の絶対値が１より大きくすることを特徴とする上記５２記載の光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２４】
〔５４〕リアルレイトレースを用いることを特徴とする上記５２又は５３記載の光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２５】
〔５５〕光源と、光源からの光を複数の点光源群像に分割する手段と、前記点光源像群を被検面近傍に投影する手段と、前記被検面で反射ないし屈折した前記点光源像群を検出する検出手段と、前記被検面で反射ないし屈折した前記点光源像群を前記検出手段に導く手段とを備え、検出された点光源像群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の物理量を表すパラメータを求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２６】
〔５６〕光学素子若しくは光学系を透過した光を複数の点光源像群に分割する手段と、前記点光源像群を検出する検出手段と、前記点光源像群を前記検出手段に導く手段とを備え、検出された点光源像群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の物理量を表すパラメータを求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２７】
〔５７〕光源と、光源からの光を複数の光束群に分割する手段と、前記光束群を被検面近傍に投影する手段と、前記被検面で反射ないし屈折した前記光束群を検出する検出手段と、前記被検面で反射ないし屈折した前記光束群を前記検出手段に導く手段とを備え、検出された光束群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の物理量を表すパラメータを求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２８】
〔５８〕光学素子若しくは光学系を透過した光を複数の光束群に分割する手段と、前記光束群を検出する検出手段と、前記光束群を前記検出手段に導く手段とを備え、検出された光束群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の物理量を表すパラメータを求めることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１２９】
〔５９〕カメラ、内視鏡、顕微鏡等のズームレンズの光学系を対象にしていることを特徴とする上記３５から５８の何れか１項記載の光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１３０】
〔６０〕上記３５から５８の何れか１項記載の処理方法を用いていることを特徴とする物理量測定処理装置。
【０１３１】
〔６１〕測定機を制御するコンピュータとリアルレイトレースを行うコンピュータとが同一であることを特徴とする光学素子又は光学系の物理量測定方法又は測定機又は測定されたもの。
【０１３２】
〔６２〕被測定光学素子又は光学系に光を入射し、その光学素子又は光学系から射出される光の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の屈折率分布型を求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１３３】
〔６３〕被測定光学素子又は光学系に光線を入射し、その光学素子又は光学系から射出される光線の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の屈折率分布型を求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１３４】
〔６４〕被測定光学素子又は光学系に光束を入射し、その光学素子又は光学系から射出される光束の状態を測定し、その測定値よりリアルレイトレースを用いることにより前記光学素子又は光学系の屈折率分布型を求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１３５】
〔６５〕被検光学素子又は光学系中の被検面に光を入射させる手段と、その光が被検光学素子又は光学系中の被検面より反射又は屈折した光を検出する光検出手段と、前記被検面で反射又は屈折された光を前記光検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の屈折率分布型を測定する屈折率分布型測定機において、前記光学素子又は光学系中の被測定面より前記光検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光検出手段における光の状態が、測定された光の状態と等しくなるような被検面の屈折率分布型を計算で求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１３６】
〔６６〕被検光学素子又は光学系中の被検面に光線を入射させる手段と、その光線が被検光学素子又は光学系中の被検面より反射又は屈折した光線を検出する光線検出手段と、前記被検面で反射又は屈折された光線を前記光線検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の屈折率分布型を測定する屈折率分布型測定機において、前記光学素子又は光学系中の被測定面より前記光線検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光線検出手段における光線の状態が、測定された光線の状態と等しくなるような被検面の屈折率分布型を計算で求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１３７】
〔６７〕被検光学素子又は光学系中の被検面に光束を入射させる手段と、その光束が被検光学素子又は光学系中の被検面より反射又は屈折した光束を検出する光束検出手段と、前記被検面で反射又は屈折された光束を前記光束検出手段に導く光学素子又は光学系で構成される光学素子又は光学系の各面の屈折率分布型を測定する屈折率分布型測定機において、前記光学素子又は光学系中の被測定面より前記光束検出手段までの光学素子又は光学系の全光学素子の設計値若しくは測定値を基に、光線追跡の計算を行い、前記光束検出手段における光束の状態が、測定された光束の状態と等しくなるような被検面の屈折率分布型を計算で求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１３８】
〔６８〕被測定光学素子又は光学系あるいは測定機の光学素子又は光学系の製造誤差を含んだ光学素子又は光学系でリアルレイトレースを行うことを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１３９】
〔６９〕測定機の光学素子又は光学系内部の変動量を測定し、変動量を考慮した光学素子又は光学系でリアルレイトレースを行うことを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４０】
〔７０〕光学素子又は光学系の前面から１面ずつ測定して屈折率分布型を求め、次の面では前に求めた屈折率分布型を含んだ光学素子又は光学系でリアルレイトレースを行い、その面の屈折率分布型を求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４１】
〔７１〕前記測定値を目標値、求める面の屈折率分布型を未知数とした方程式の解法処理をリアルレイトレースを用いて行うことを特徴とする上記６２から６４の何れか１項記載の光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４２】
〔７２〕前記測定値を目標値、任意の位置又は任意の軸を基準とした複数の面あるいはレンズ群の屈折率分布型を未知数とした方程式の解法処理をリアルレイトレースを用いて行うことを特徴とする上記６２から６４の何れか１項記載の光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４３】
〔７３〕前記未知数の算出に、最適化処理を用いることを特徴とする上記７１又は７２記載の光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４４】
〔７４〕波動光学的点像強度分布を評価関数とすることを特徴とする上記７３記載の光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４５】
〔７５〕光束の像を測定する場合の結像関係が等倍結像あるいは不等倍結像の何れかを用いることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４６】
〔７６〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように屈折率分布型を最適化することで、少なくとも一つの屈折率分布型を求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４７】
〔７７〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように傾きと偏り量を最適化することで、傾きと偏り量の少なくとも一つの屈折率分布型を表すパラメータを求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４８】
〔７８〕被測定光学素子又は光学系に光線を入射させ、この光線と光軸とのなす角度をさまざまに変化させ、それぞれの角度に対して被検面からの反射又は屈折する光線の位置を検出し、全ての状態において測定された光線の位置と光線追跡で求めた光線位置との差が小さくなるように、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量を最適化することで、光軸と直交しかつそれぞれが直交する２方向の傾きと偏り量の少なくとも一つの屈折率分布型を表すパラメータを求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１４９】
〔７９〕測定しようとする面のみかけ上の曲率中心、すなわち、被測定面と屈折率分布型測定機の観察系との間に存在する別の面によって結像される被測定面の曲率中心の像の位置から光軸に沿った方向にずらした位置に指標を投影し、測定しようとするレンズ面から反射される指標の像のずれ量を計算で求めておき、この位置に結像される指標の像の反射像を検出することを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５０】
〔８０〕投影する指標に対する指標の反射像の倍率の絶対値が１より大きくすることを特徴とする上記７９記載の光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５１】
〔８１〕リアルレイトレースを用いることを特徴とする上記７９又は８０記載の光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５２】
〔８２〕光源と、光源からの光を複数の点光源群像に分割する手段と、前記点光源像群を被検面近傍に投影する手段と、前記被検面で反射ないし屈折した前記点光源像群を検出する検出手段と、前記被検面で反射ないし屈折した前記点光源像群を前記検出手段に導く手段とを備え、検出された点光源像群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の屈折率分布型を表すパラメータを求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５３】
〔８３〕光学素子若しくは光学系を透過した光を複数の点光源像群に分割する手段と、前記点光源像群を検出する検出手段と、前記点光源像群を前記検出手段に導く手段とを備え、検出された点光源像群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の屈折率分布型を表すパラメータを求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５４】
〔８４〕光源と、光源からの光を複数の光束群に分割する手段と、前記光束群を被検面近傍に投影する手段と、前記被検面で反射ないし屈折した前記光束群を検出する検出手段と、前記被検面で反射ないし屈折した前記光束群を前記検出手段に導く手段とを備え、検出された光束群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の屈折率分布型を表すパラメータを求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５５】
〔８５〕光学素子若しくは光学系を透過した光を複数の光束群に分割する手段と、前記光束群を検出する検出手段と、前記光束群を前記検出手段に導く手段とを備え、検出された光束群の位置を基に近軸光線追跡若しくはリアルレイトレースを行い、前記被検面の屈折率分布型を表すパラメータを求めることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５６】
〔８６〕カメラ、内視鏡、顕微鏡等のズームレンズの光学系を対象にしていることを特徴とする上記６２から８５の何れか１項記載の光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５７】
〔８７〕上記６２から８５の何れか１項記載の処理方法を用いていることを特徴とする屈折率分布型測定処理装置。
【０１５８】
〔８８〕測定機を制御するコンピュータとリアルレイトレースを行うコンピュータとが同一であることを特徴とする光学素子又は光学系の屈折率分布型測定方法又は測定機又は測定されたもの。
【０１５９】
【発明の効果】
以上の説明から明らかなように、本発明の光学素子又は光学系の物理量測定方法においては、被測定光学素子又は光学系から射出される光の状態を測定し、その測定値よりリアルレイトレースを用いることにより物理量を求めるので、高い精度で光学素子の単体又は組み合わせからなる光学系の物理量を表すパラメータを求めることができる。
【図面の簡単な説明】
【図１】本発明の偏心測定方法で用いるリアルレイトレースを説明するための図である。
【図２】本発明の１実施例の光学素子又は光学系の偏心測定方法を実施する処理装置のブロック図である。
【図３】図２の装置で行う処理のフローチャートである。
【図４】図３の偏心量算出処理の詳細を示すフローチャートである。
【図５】図４の偏心量算出処理を前面から後面に１面ずつ順に行う処理のフローチャートである。
【図６】反射像の基準軸からの振れ量を測定するための測定機の一例を示す図である。
【図７】オートコリメータで反射像の基準軸からの振れ量を測定する様子を説明するための図である。
【図８】像点位置算出のためのリアルレイトレースの一例を説明するための図である。
【図９】光束の重心位置、光束の広がり算出のためのリアルレイトレースの一例を説明するための図である。
【図１０】レンズ面、単レンズ、レンズ群の偏心量の定義の例を示す図である。
【図１１】斜入射法を用いた非球面偏心測定機に本発明のリアルレイトレース法を適用した実施例を示す図である。
【図１２】偏心量εｒ、δｒ、εθ、δθの定義を示す図である。
【図１３】本発明のリアルレイトレース法を用いた心出顕微鏡の例を示す図である。
【図１４】本発明によりマイクロレンズアレイで点光源像群を作って偏心量を求める配置を示す図である。
【図１５】図１４における各点光源の像の例を示す図である。
【図１６】本発明によるシャックハルトマン法の応用例を示す図である。
【図１７】本発明によりオートコリメータで不等倍像を作って振れ量を測定する様子を説明するための図である。
【図１８】本発明によりリアルレイトレースを用いて光学素子の屈折率分布測定・評価・解析を行う実施例を説明するための図である。
【符号の説明】
１…演算処理装置
２…表示装置
３…入力装置
４…記憶装置
５…外部媒体
６…プリンター
７…ＬＡＮ
８…測定機
９…光学素子測定機
１０…光学系設計装置
５１…被測定面
５２…光源（指標）
５３…コリメータレンズ
５４…像面
６１…被検面
６２…マイクロレンズアレイ
６３…投影レンズ
６４…ハーフミラー
６５…撮像素子
７１…被検光学素子又は光学系
７２…コリメートレンズ
７３…マイクロレンズアレイ
７４…リレーレンズ
７５…撮像素子
８１…Ｈｅ−Ｎｅレーザー
８２…ビームスプリッタ
８３…被検光学素子
８４…基準光学系
８５…ビームスプリッタ
８６…スクリーン
１０２…光学系
１０３…投影レンズ
１０５…顕微鏡対物レンズ
１０６…ズームレンズ
１０７…ＣＣＤカメラ
１１１…ミラー
１１５…ビームスプリッタ
１２０…非球面
１２１…被検非球面レンズ
１３４…三角プリズム
１４１…偏心測定機
１４９…信号処理回路
１５０…計算機
１５１…ＴＶモニター
１６０…心出顕微鏡
１６１…光源
１６２…ピンホール
１６３…採光レンズ
１６４…非検面
１６５…被検レンズ
１６６…結像レンズ
１６７…ハーフミラー
１６８…焦点板
１６９…接眼レンズ
１７０…眼
１７１…変倍系
１７２、１７３、１７４…光学面
２０１…半導体レーザー
２０２…測定用光学系
２０３…被測定レンズ
２０４…ビームスプリッタ
２０５…イメージローテータ
２０６…基準軸設定用光学系
２０７…ＣＣＤカメラ
２０８…モニタテレビ
２０９…ＣＲＴ
２１０…演算処理部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a physical quantity measuring method for an optical element or an optical system.
[0002]
[Prior art]
Among the physical quantities of lens systems (including shape, radius of curvature, surface spacing, aspherical coefficient, refractive index distribution, etc.), the autocollimation method has been known as a conventional method for measuring the amount of eccentricity of lens systems. Yes. The autocollimation method is based on the apparent center of curvature of the surface to be measured, that is, the position of the image of the center of curvature of the surface to be measured formed by another surface existing between the surface to be measured and the observation system. In this method, an index is projected, and an equal-magnification reflected image by the surface to be examined is generated at the same position as the projected position of the index.
[0003]
In the above case, if all lens surfaces are not decentered with respect to the measurement reference axis, an index image is formed on this reference axis, but if any lens surface is decentered, the reference axis is shifted from the reference axis to the reference axis. On the other hand, a reflected image is formed at a position separated in a direction perpendicular to the direction. The amount of shake Δ from the reference axis of the reflected image has a functional relationship with the amount of eccentricity ε of each lens surface. Therefore, the amount of shake of the same-magnification reflected image of the index image projected on the apparent spherical center position for each lens surface If Δ is measured, the amount of eccentricity of each lens surface relative to the measurement reference axis can be obtained by calculation.
[0004]
FIG. 7 is a schematic diagram showing a shake amount Δ generated by one measured surface 51 having an eccentric amount (axis inclination) ε. As shown in FIG. 7, the light beam from the light source (index) 52 is converged by the collimator lens 53 and is incident so as to converge at the spherical center position on the measurement reference axis of the measurement target surface 51. When the convergence position of the light beam coincides with the sphere center position of the surface to be measured 51, the light beam enters the surface to be measured 51 perpendicularly. However, if the convergence position of the light beam and the sphere center position of the surface to be measured 51 do not match (the surface to be measured 51 is ε-eccentric), the light beam is obliquely incident on the surface to be measured 51. Here, in the case of vertical incidence, the reflected light generated on the measurement target surface 51 travels backward along the optical path at the time of incidence and converges to a position conjugate with the light source (index) 52. On the other hand, in the case of oblique incidence, the reflected light generated on the measurement target surface 51 deviates from the optical path at the time of incidence, and converges at a position deviated by Δ from the converged position when vertically incident.
[0005]
[Problems to be solved by the invention]
However, in the above prior art, since the relationship between the shake amount Δ measured on the image plane 54 and the eccentric amount ε of the lens surface 51 is proportional, the proportional coefficient of this proportional relationship is obtained by paraxial calculation. The accuracy of the amount of eccentricity ε obtained by calculation could be reduced. When the magnification β obtained by paraxial calculation of the collimator lens 53 shown in FIG. 7 is used, the relational expression between the shake amount Δ and the eccentric amount ε of the measured surface 51 is expressed as follows:
Δ = 2βrε (1)
It becomes.
[0006]
The present invention has been made in view of such a problem of the prior art, and its purpose is to provide a method for obtaining a parameter representing a physical quantity including an eccentricity of an optical system composed of a single element or a combination of optical elements with high accuracy. Is to provide.
[0007]
[Means for Solving the Problems]
The method for measuring a physical quantity of an optical element or an optical system according to the present invention that achieves the above object is to vary the angle between the optical element to be measured or the optical axis of the optical element to be measured or the optical system in various ways. Incident light,
For each angle, measure the characteristics of the light beam emitted from the measured optical element or optical system and imaged on the image plane by a condensing optical system,
Real ray tracing is performed for each angle,
In all the respective angles, in the real ray trace, the difference between the measured ray characteristics and the ray characteristics obtained in the real ray trace is reduced. Of the measured optical element or optical system Eccentricity or Of the lens surface of the optical element to be measured or the optical system In this method, the amount of eccentricity of at least one optimized optical element or optical system to be measured is obtained by changing an inclination and a deviation amount.
[0008]
In this case, the characteristics of the light beam include the image point position of the light beam, the light intensity distribution at the image point position of the light beam, and the wavefront aberration of the light beam.
[0009]
In the case of the light beam image point position and the light intensity distribution at the light beam image point position, the physical quantity can be the amount of decentration of the optical element to be measured or the optical system.
Further, in the case of wavefront aberration of light rays, the physical quantity can be the refractive index distribution of the measured optical element or optical system.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The principles and examples of the optical element or optical system eccentricity measuring method of the present invention will be described below.
[0011]
In order to solve the above-described problems, the present invention uses a real ray trace in the process of calculating the amount of surface eccentricity from the measured shake amount Δ. Real ray tracing is also called real ray tracing. This is a method of calculating the position, direction, etc. of the light beam by strictly calculating the laws of refraction and reflection. Ray tracing can be performed in consideration of the amount of eccentricity of the optical system and aspherical surfaces, and it is widely used for designing and evaluating optical systems using computers.
[0012]
As shown in FIG. 1, the real ray tracing process is performed by using a position vector P of a light ray incident on the optical system. ₀ , Direction vector R ₀ Intersection point P with the first surface of the optical system (the first surface that intersects the light beam) ₁ And the normal vector H of the surface at the intersection point ₁ To the incident angle of light θ _i1 Is decided. Refractive index n of incident side medium ₀ And refractive index n on the exit side ₁ From the Snell's law, the exit angle θ _o1 , Exit light direction vector R ₁ Is obtained. Position vector P of intersection of first surface ₁ , Exit light direction vector R ₁ Is used as the incident light ray on the second surface (the surface that intersects the light ray next), and the intersection point with the next surface and the emitted light ray are repeatedly obtained.
[0013]
Real ray tracing allows you to calculate how the light beam or light beam that has entered the optical system passes through the optical system and is emitted. The position of the image point of the light beam or light beam, the center of gravity of the light beam, and the state (size, shape) of the light beam It is possible to calculate various characteristics of the optical system such as the direction and position of the light beam, the state of the light beam (intensity and polarization state), the spread of the light beam, and the local paraxial amount (Japanese Patent Laid-Open No. 11-287947). .
[0014]
The shake amount Δ mentioned in the problem to be solved by the invention is measured, for example, by a measuring instrument including an optical system shown in FIG. The shake amount Δ is a process for obtaining the image point position or the gravity center position of the light beam. A light beam (principal light beam) that passes from the object point (semiconductor laser) 201 and passes through the center of the aperture is sequentially projected onto the curvature center of each surface of the lens 203 to be measured via the measurement optical system 202 and the beam splitter 204. Then, the reflected light is traced to the image plane (the light receiving surface of the CCD camera 207), and the coordinate value on the image plane (the light receiving surface of the CCD camera 207) is obtained. The stop center here is not limited to the center of the stop of the assembled lens system to be tested (the lens to be measured 203), but the intersection of the test surface and the optical axis or global coordinates or the rotation center axis of the image rotator 205 is selected. But you can. Further, the center of gravity and shape of the light beam are obtained by tracing a plurality of light beams emitted from the object point (semiconductor laser) 201 and obtaining the light beams emitted from the optical system (measuring optical system) 202, respectively. From the position and direction of the emitted light, the intensity of the light, etc., the position of the center of gravity, the size, the shape, etc. of the light beam on the image plane (the light receiving surface of the CCD camera 207) are obtained.
[0015]
The light intensity and polarization state are determined by the energy transmittance and energy reflectivity according to the incident angle, exit angle, and refractive index before and after the surface. By multiplying, the intensity of the light can be obtained. When the surface is coated, the transmittance and reflectance can be calculated using the characteristic matrix for each layer. The polarization state can also be calculated by tracking the Jones vector using the above-mentioned transmittance and reflectance ("Principle of optics" Tokai University publication, "Crystal optics" Applied Physics Society optical social gathering, "Optical thin film" Kyoritsu publication reference).
[0016]
Hereinafter, an embodiment of the method for measuring the eccentricity of the optical element or optical system of the present invention will be described.
[0017]
FIG. 2 shows a block diagram of a processing apparatus that performs the eccentricity measuring method. This apparatus includes a measuring device 8 that measures the state of the image of the luminous flux or the state of the light beam as described above, a display device 2, an input device 3 such as a keyboard, a storage device 4 such as a magnetic disk, a printer 6, and the like. And an arithmetic processing unit 1 that performs overall processing and performs processing. In addition, it is connected to a LAN 7 for exchanging data, processing methods, etc. with an external optical element measuring machine 9, an optical system design apparatus 10, etc., and is connected to an external medium 5 such as a floppy disk or a magneto-optical disk. An output mechanism is also provided.
[0018]
As described above, from the measurement device 8, in addition to the measurement data of the state of the image of the light beam emitted from the optical system to be detected or the state of the light beam, the surface interval data related to the measurement optical system, the movement amount, and the like are also sent. .
[0019]
The optical element measuring machine 9 is a set of various measuring machines such as the surface shape of the optical element, the surface interval, the refractive index of the medium, the coating film thickness, and the like. Measurement data of r, d, n, coating data, manufacturing error data, etc. are sent. Here, r: curvature or radius of curvature (surface equation in the case of an aspherical surface), d: surface spacing, n: refractive index of medium, coating data: complex refractive index and film thickness of each film.
[0020]
The optical system design apparatus 10 is an apparatus for designing an optical system. From this apparatus, design value data such as r, d, and n of the test optical system and the measurement optical system are sent. Further, it is possible to capture the eccentricity data obtained by the method of the present invention and reflect it in the design or to evaluate the optical system.
[0021]
The apparatus shown in FIG. 2 performs the processing shown in FIG. That is, in Step 1, the test optical system used for the step 2 eccentricity calculation processing from the input device 3, the storage device 4, the external medium 5, the measuring device 8, the optical element measuring device 9, and the optical system design device 10 in FIG. R and d of the measurement optical system (including the distance between movements for measurement in the measurement optical system), n data, coating data, manufacturing error data, state data of the image of the light beam emitted from the test optical system, or , The measurement data of the state of the light, the already known eccentricity data, the type of eccentricity to be obtained, the range, etc. are input as necessary.
[0022]
In Step 2, based on the various data input in Step 1, the arithmetic device 1 in FIG.
[0023]
In Step 3, the obtained eccentricity amount is output to the display device 2, the storage device 4, the external medium 5, and the printer 6 in FIG. 2. Alternatively, the data is transferred to the measuring device 8, the optical element measuring device 9, the optical system design apparatus 10, and the like.
[0024]
Next, the process corresponding to the eccentricity calculation process Step 2 in FIG. 3 will be described using an example in which a real ray trace is used to solve the simultaneous equations in FIG. When applied to the eccentricity measurement using the conventional autocollimation method, the simultaneous equations are as follows, for example.
[0025]
The evaluation function is F _i (X ₁ , X ₂ , X _Three , ..., x _n ), I = 1, 2, 3,... N: For example, the image point position. For example, as shown in FIG. 8, the image point position can be calculated as the intersection of the light beam emitted from the object point and entering the optical system through the center of the aperture and the image plane as shown in FIG. . In addition to the image point position, what can be treated as an evaluation function is a light beam (a plurality of light beams) incident on the optical system from an object point as shown in FIG. Real-rate with a measurable one such as the position of the center of gravity, spread of light flux, wave optical point image intensity distribution, light beam state, etc. in a cross section (Fig. 9 (b), (c)). Anything that can be calculated by running a race can be handled.
[0026]
Variable x _j (1, 2, 3,... M), j = 1, 2, 3,... M: For example, the amount of eccentricity in the surface, single lens, or lens group shown in FIG. FIG. 10A shows the definition of the amount of eccentricity of the surface, and the inclination ε in the xz plane that is the reference axis of the central axis of the surface on the reference axis. _x , Inclination ε in the yz plane _y Represents the amount of eccentricity. FIG. 10B shows the definition of the amount of eccentricity of the lens, and the inclination ε in the xz plane between the center axis and the reference axis of the lens. _x , Inclination ε in the yz plane _y And the amount of deviation δ in the xz plane from the reference axis at the center of the first lens surface _x , Displacement amount δ in the yz plane _y And the amount of eccentricity. FIG. 10C shows the definition of the amount of eccentricity of the lens group, which is the same as FIG. 10B. FIG. 10D shows a definition of the amount of eccentricity of the lens different from that in FIG. 10B, and it is assumed that the lens rotates about an arbitrary point P (X, Y), and the reference of the center axis is shown. Inclination ε in the xz plane with the axis _x , Inclination ε in the yz plane _y Represents the amount of eccentricity.
[0027]
Where a _ij = ∂F _i / ∂x _j (Partial differentiation), the initial evaluation function value is F _i0 , The initial variable value x _j0 Then,
F _i ≒ F _i0 + Σa _ij (X _j -X _j0 (2)
It becomes. This F _i Is the measurement result image plane position F _im The amount of eccentricity (variable x _j ) Can be calculated.
[0028]
In Step 4, the eccentricity (variable) is in the initial state (x _j0 ) Image point position (evaluation function F) _i0 ) With real ray tracing.
[0029]
From Step 5 to Step 7, a _ij Matrix A _ij Ask for. One eccentricity (variable x _i ) Is slightly changed, real ray tracing is performed, and an image point position (evaluation function F) with respect to a unit change amount of one eccentricity amount is performed. _i ) Change amount ∂F _i / ∂x _j Ask for.
[0030]
In Step 8, the amount of eccentricity (variable x _i ) And the image point position after the change (evaluation function F) _i )
[0031]
In Step 9, the image point position obtained by the optimization (evaluation function F _i ) And the image plane position F as the measurement result _im And evaluate whether they are close enough. If not enough, the image point position (evaluation function F) after optimization in Step 10 _i ), Eccentricity (variable x _j ) For each initial state (evaluation function) _i0 , Variable x _j0 ), And the process returns to Step 5. When it is evaluated that the state is sufficient in Step 9, the process is terminated.
[0032]
In the above processing, in the conventional autocollimation method, the reflected light from the optical system to be measured is measured. A light beam is incident from the front of the test optical system, and the imaging position (image point position or barycentric position) of the reflected light from the measurement surface is measured. The amount of the test surface is obtained by performing the above processing using the measured position as an evaluation function and the amount of eccentricity of the test surface as a variable. In addition to the optical system, the calculated amount of eccentricity is calculated as the data of the optical system. Processing is performed one by one from the front side to the rear side. The process is illustrated in FIG.
[0033]
As another method different from the auto-collimation method, there is a method of measuring one or a plurality of image point positions, light beam barycentric positions, light beam spreads, light beam states, etc., which can be handled as evaluation functions, and using them as evaluation functions. One or more test surfaces, single lens, which are made variable by performing an optimization process with the amount of eccentricity of one or more test surfaces, single lens, and group lens in the range where light passes at the time of measurement. The amount of eccentricity of the group lens can be calculated at once.
[0034]
Further, a local paraxial amount can be used instead of the paraxial amount used in the conventional autocollimation method. An arbitrary reference ray from the light source 52 to the image plane 54 in FIG. 7 is set, and the spread of a minute light beam propagating in the vicinity of the reference ray is calculated over the entire system, whereby the reference in the asymmetric optical system considering the amount of decentration is obtained. A local paraxial quantity in the vicinity of the ray is obtained. Information obtained as local paraxial quantities includes imaging position, imaging orientation, focal line orientation, magnification, focal length, pupil position, principal point position, nodal position, astigmatism, field distortion, illumination, etc. (Japanese Patent Laid-Open No. 11-287947), By adopting the magnification of the local paraxial amount instead of β in the equation (1), the accuracy of the eccentric amount of the optical system to be tested can be improved.
[0035]
Further, the radius of curvature r, the surface spacing d, the refractive index n, and the like of the actual surface of the optical system that performs the real ray tracing may differ from the intended optical system due to manufacturing errors and the like. The data of the optical system that performs the real ray tracing is replaced with data such as the radius of curvature r, the surface interval d, and the refractive index n of the surface measured by the optical element measuring machine 9 of FIG. 2, or the optical element of FIG. Manufacturing error data such as the radius of curvature r, surface distance d, and refractive index n measured by the measuring instrument 9 or the like, or data such as the amount of tolerance such as the radius of curvature r, surface distance d, and refractive index n, etc. It adds to the curvature radius r of the surface, the surface interval d, the refractive index n, and the like. By treating this as optical system data and performing real ray tracing, a tracking result closer to the actual can be calculated, and the accuracy of the required eccentricity can be improved.
[0036]
In the autocollimation method, the light beam is incident so as to converge at the spherical center position of the surface to be measured. In order to realize this, it may be necessary to perform measurement by moving the inside of the measuring instrument optical system according to the surface to be measured. The amount of fluctuation inside the measuring instrument optical system corresponding to the surface to be measured is measured and added to the optical system that performs the real ray tracing. By treating this as optical system data and performing real ray tracing, a tracking result closer to the actual can be calculated, and the accuracy of the required eccentricity can be improved.
[0037]
In addition, examples of the optical system that performs the decentration measurement, evaluation, and analysis using the real ray trace include a camera, an endoscope, a zoom lens such as a microscope, and the like.
[0038]
Next, FIG. 11 and FIG. 13 show an embodiment in which the decentering measurement, evaluation, and analysis of an optical system or optical element is performed using real ray tracing.
[0039]
FIG. 11 is a diagram showing an example in which real ray tracing is applied to an aspherical eccentricity measuring machine using the oblique incidence method shown in Japanese Patent Laid-Open Nos. 7-120218 and 9-222380, and accuracy is improved. It is. FIG. 11A shows a state in which a light beam is incident near the optical axis of the aspheric surface 120, and FIG. 11B shows a state in which the light beam is incident obliquely on the periphery of the aspheric surface 120. In any case, the light beam reflected by the surface of the aspheric surface 120 proceeds to the mirror 111, the projection lens 103, the beam splitter 115, the microscope objective lens 105, the triangular prism 134, and the zoom lens 106, and becomes a bright spot on the CCD camera 107. To form an image. When the aspheric surface 120 is rotated, the bright spot of the reflected light beam on the CCD camera 107 draws a curve and rotates on the CCD camera 107. By analyzing the locus of this bright spot, the aspheric lens 121 of the test aspheric lens 121 is analyzed. The eccentricity δr and the inclination εr of the aspherical surface 120 can be obtained together with the azimuth angles εθ and δθ.
[0040]
However, in the above-mentioned two patents, paraxial calculation and paraxial calculation based on local curvature are used to analyze the trajectory, so that the accuracy is not necessarily good.
[0041]
Therefore, in the present invention, the optical design data of all surfaces of the optical system of the decentering measuring instrument 141, that is, each surface
r: radius of curvature (in the case of aspherical surface equation)
d: Distance to the next surface
n: Refractive index of the medium
Is input to the computer 150, and the trajectory when the test aspheric lens 121 observed by the CCD camera 107 is rotated with εr and δr of the test aspheric surface and the azimuth angles εθ and δθ of εr and δr as variables is used. Optimal values of εr, δr, εθ, and δθ are obtained so that the traces of the bright spot traced by the real ray match.
[0042]
In this way, εr, δr, εθ, and δθ can be obtained with higher accuracy than the paraxial ray analysis.
[0043]
In the figure, reference numeral 149 is a signal processing circuit for processing the output of the CCD camera 107, and reference numeral 151 is a TV monitor.
[0044]
ε _x = Εr · cosεθ
ε _y = Εr · sinεθ
δ _x = Δr · cosδθ
δ _y = Δr · sinδθ
Therefore, instead of εr, δr, εθ, δθ, the component of eccentricity ε _x , Ε _y , Δ _x , Δ _y You may ask for.
[0045]
FIG. 12 shows the definitions of εr, δr, εθ, and δθ.
[0046]
Next, FIG. 13 is a diagram showing an example of a centering microscope 160 using a real ray trace, and this centering microscope 160 measures the eccentricity of one lens, the eccentricity of one surface of the lens, and a plurality of lenses. This is used when joining while examining the eccentricity of each lens.
[0047]
In the centering microscope 160, the light emitted from the light source 161 passes through the target pinhole 162, the daylighting lens 163, and the beam splitter (half prism) 115 and enters the test surface 164. The light beam reflected by the test surface 164 proceeds to the beam splitter (half prism) 115, the optical system 102 having the variable magnification system 171, the half mirror 167, and the imaging lens 166, and forms an image as a bright spot on the CCD camera 107. To do. When the test lens 165 is rotated, the eccentricity of the test surface 164 can be obtained from the position or locus of the bright spot on the CCD camera 107. Instead of the CCD camera 107, the decentering of the test surface 164 may be obtained by observing with the eye 170 via the eyepiece lens 169 from the position or locus of the bright spot on the focusing screen 168.
[0048]
Here, the image of the pinhole 162 by the daylighting lens 163 may not be the spherical center of the test surface 164 but may be a position deviating from the spherical center. FIG. 13 illustrates such a case. Yes. This is called an unequal magnification imaging state. Similarly, the eccentricity of the surfaces 172, 173, 174 below the test surface 164 can be obtained.
[0049]
In the past, paraxial theory has been used to determine the test surface eccentricity from the position or locus of the bright spot. However, the accuracy was slightly poor due to the aberration (particularly distortion) of the optical system of the centering microscope 160. Therefore, in the present invention, each surface of the optical system of the centering microscope 160 is
r: radius of curvature (in the case of aspherical surface equation)
d: Distance to the next surface
n: Refractive index of the medium
Is input to the computer 150, and the eccentricity of the test surface 164 is obtained such that the position of the bright spot on the CCD camera 107 substantially coincides with the position or locus of the bright spot, thereby obtaining the test surface 164. You can know the eccentricity.
[0050]
Next, an example of the eccentricity measurement in the case where the lens system having a plurality of surfaces includes an aspheric lens surface will be described. Since an aspherical surface has an aspherical axis that is uniquely determined, for example, a parameter indicating the eccentricity of the inclination ε of the lens surface and the deviation amount δ is required. The parameter representing the eccentricity is a component in two directions orthogonal to the optical axis and orthogonal to each other (ε _x , Ε _y ), (Δ _x , Δ _y ). Further, polar coordinates (εr, εθ), (δr, δθ), etc. may be used as shown in FIG. In order to obtain parameters representing these eccentricities, the following may be performed.
[0051]
Generally, when the lens surface to be measured is an aspherical surface, the light intensity distribution of the reflected image of the index when the surface has an inclination ε, and the reflected image of the index when there is a deviation amount δ on this surface Therefore, real ray tracing or paraxial ray tracing is performed using the light intensity distribution of the reflected image of the measured index as a target value, for example, using the slope ε and the deviation δ of the measured surface as variables. By optimizing the slope ε and the deviation amount δ, a parameter representing the eccentricity can be obtained.
[0052]
The above light intensity distribution means the shape of the intensity distribution of the light detected by the detector and the intensity distribution of the light calculated geometrically or by wave optics.
[0053]
In order to evaluate the test optical system, it is only necessary to obtain at least one required parameter from among parameters representing decentration.
[0054]
In FIG. 7, only a part of the light beam emitted from the light source 52 is incident on the test optical system, and the angle between the light beam and the optical axis is changed in various ways. The position of the light beam reflected from the inspection surface is detected, real ray tracing or paraxial ray tracing is performed for each state, and the difference between the light ray position measured in all states and the ray position obtained by ray tracing is used. The parameter representing the eccentricity can also be obtained by optimizing the slope ε and the amount of deviation δ so that.
[0055]
Further, as shown in FIG. 14, a point light source image group is created by the microlens array 62, projected onto the test surface 61 by the projection lens 63, and the light reflected or refracted by the test surface 61 is sent to the half mirror 64. 15 (when reflected by the test surface 61), the image sensor 65 detects the image of each point light source as illustrated in FIG. 15, and a real ray trace or paraxial with the position of each point light source image as a target. By performing ray tracing and optimizing the slope ε and the amount of deviation δ so that the difference between the position of the point light source image measured in all states and the position of the point light source image obtained by ray tracing is reduced, eccentricity can also be achieved. Can be obtained.
[0056]
As an application example of the Shack-Hartmann method, as shown in FIG. 16, the light transmitted through the test optical element or optical system 71 is guided to the microlens array 73 via the collimator lens 72 to create a point image group, The point image group is detected by the imaging device 75 via the lens 74, and the real ray trace or paraxial ray tracing is performed with the position of each point image as a target, and the position and ray tracing of the point light source image measured in all states are performed. The parameter representing the eccentricity can also be obtained by optimizing the inclination ε and the amount of deviation δ of each surface so that the difference from the position of the point light source image obtained in step 1 is reduced.
[0057]
Further, in a single lens including an aspheric surface to be measured, the inter-surface eccentricity ε between the front surface and the rear surface of the lens _L Is obtained by an inter-surface eccentricity measuring machine or the like, the inclination ε (ε ₁ , Ε ₂ ) And deviation amount δ (each δ ₁ , Δ ₂ ) And the amount of front tilt obtained from the measurement of the reflected image of the index ε ₁ ', Back slope ε ₂ 'And ε _L , And front paraxial radius of curvature R ₁ , Rear paraxial radius of curvature R ₂ From the lens thickness T, the inclination ε and the deviation δ between the front and rear surfaces can be calculated as follows. The parameter ε representing the eccentricity ₁ , Ε ₂ , Ε ₁ ', Ε ₂ ', Ε _L , Δ ₁ , Δ ₂ Represents the respective components of x and y.
[0058]
ε ₁ '= Ε ₁ + Δ ₁ / R ₁ ... (3)
ε ₂ '= Ε ₂ + Δ ₂ / R ₂ ... (4)
ε ₂ = Ε ₁ + Ε _L ... (5)
δ ₂ = Δ ₁ + Tε ₁ ... (6)
From equations (3)-(6)
δ ₁ = (R ₁ R ₂ + R ₁ T) ε ₁ '/ (R ₂ -R ₁ + T)
-R ₁ R ₂ (Ε ₂ '−ε _L ) / (R ₂ -R ₁ + T) (7)
δ ₂ = R ₁ R ₂ ε ₁ '/ (R ₂ -R ₁ + T)
-(R ₁ R ₂ -R ₂ T) (ε ₂ '−ε _L ) / (R ₂ -R ₁ + T) (8)
ε ₁ = -R ₁ ε ₁ '/ (R ₂ -R ₁ + T)
+ R ₂ (Ε ₂ '−ε _L ) / (R ₂ -R ₁ + T) (9)
ε ₂ = Ε ₁ '+ Ε _L ···(Ten)
The above calculation is based on the paraxial nature of the optical system, and the amount of decentration can be obtained by the equations (7) to (10). When calculating the eccentricity of each surface, the eccentricity between the surfaces of both surfaces of the lens including the aspherical surface can also be calculated as a constraint condition.
[0059]
Needless to say, an equation mathematically equivalent to the equations (7) to (10) (for example, converted into polar coordinates) may be used.
[0060]
By the way, when each surface of a lens system having a plurality of surfaces is measured using the autocollimation method (FIG. 7), the apparent center of curvature of the surface 51 to be measured, that is, the surface 51 to be measured and the observation system An index or a light source image is projected to the position of the image of the center of curvature of the surface to be measured 51 formed by another surface existing between them, and an equal-magnification reflected image by the surface to be measured 51 is converted into the index or light source. When the image is generated at the same position as the image projection position, an index image or a light source image reflected from other than the lens surface to be measured may be generated in the vicinity of the index or light source image by the lens surface 51 to be measured. It is possible. In this case, it is difficult to distinguish which is the index image or the light source image by the lens surface to be measured.
[0061]
Therefore, in such a case, the apparent curvature center of the surface to be measured, that is, the curvature of the measured surface 51 formed by another surface existing between the measured surface 51 and the observation system. An index or a light source image is projected at a position shifted from the position of the central image in the direction along the optical axis. This is shown in FIG. This corresponds to the case where the position of the light source 52 or the collimator lens 53 in FIG. 7 is shifted along the optical axis. At this time, the position of the reflected image is different from the position where the index or the light source image is projected, and the magnification is not equal.
[0062]
In addition, the position of the index image or the light source image reflected from other than the lens surface 51 to be measured is also shifted, and generally the amount of deviation of the position of the reflected image by the lens surface 51 to be measured and the lens surface to be measured. Since the amount of positional deviation of the reflected image from other than that differs, the amount of deviation of the index image or the light source image reflected from the lens surface 51 to be measured is obtained by calculation, and the index image formed at this position Alternatively, by detecting the reflection image of the light source image, it is possible to distinguish the index image or the light source image by the lens surface 51 to be measured. Further, by setting the absolute value of the magnification of the projected index or the index for the light source image or the magnification of the reflected image of the light source image to be greater than 1, it is possible to improve the eccentricity measurement accuracy as compared with the case of imaging at the same magnification. Further, a method of detecting a light beam refracted by the test surface instead of the light beam reflected by the test surface may be used.
[0063]
Next, an embodiment for measuring, evaluating, and analyzing the refractive index distribution of an optical element using a real ray trace will be described with reference to FIG.
[0064]
The laser beam from the He-Ne laser 81 is divided into two optical paths by the beam splitter 82, one is made incident on the optical element 83 to be tested, and the other one has optical performance according to the design value of the optical element 83 to be tested. The light beams that have been incident on the reference optical system 84 and transmitted through both optical systems are combined by the beam splitter 85 and projected onto the screen 86 so as to generate interference fringes. The interference fringe image is captured by a television camera and input to a computer to analyze the fringes and obtain the phase difference distribution in the light beam on the screen 86.
[0065]
The phase difference distribution measured by such an apparatus corresponds to a wavefront aberration on the exit pupil plane when a parallel light beam is incident on the optical element 83 to be tested.
[0066]
In general, the refractive index distribution is
n (r) = n ₀ + N ₂ r ² + N _Four r ^Four + N ₆ r ⁶ + ... (11)
It is expressed in the form of
[0067]
When the thickness of the test optical element 83 in the optical axis direction is not sufficiently small and the bending of the light beam in the test optical element 83 cannot be ignored, the wavefront aberration calculated by the real ray trace is the measured wavefront aberration. To the coefficient n in equation (11) ₂ , N _Four , N ₆ Is used as a variable to optimize the refractive index distribution.
[0068]
In this case, it is considered that the deviation of the exit wavefront when the parallel light is incident on the test optical element 83 from the exit wavefront when the parallel light is incident on the reference optical system 84 is measured. If the aberration of the system 84 is small enough to be ignored, the exit wavefront becomes a spherical surface. Therefore, when the parallel light is incident on the reference optical system 84 of the exit wavefront when the parallel light is incident on the optical element 83 to be measured. The deviation from the exit wavefront coincides with the wavefront aberration when parallel light is incident on the optical element 83 to be tested.
[0069]
Therefore, real ray tracing is performed using each refractive index distribution coefficient of the medium whose refractive index distribution shape is defined by Equation (11) as a variable having the initial state as a design value, and the exit wavefront, that is, the wavefront aberration is measured. If the optimization is performed so as to fit, each coefficient is obtained.
[0070]
The above-described optical element or optical system eccentricity measuring method of the present invention can be configured as follows.
[0071]
[1] Light is incident on the optical element or optical system to be measured, the state of the light emitted from the optical element or optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. An eccentricity measuring method or measuring machine for an optical element or an optical system, or a measured one, characterized in that the amount of eccentricity is obtained.
[0072]
[2] A light beam is incident on the optical element or optical system to be measured, the state of the light beam emitted from the optical element or optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. An eccentricity measuring method or measuring machine for an optical element or an optical system, or a measured one, characterized in that the amount of eccentricity is obtained.
[0073]
[3] A light beam is incident on the optical element or optical system to be measured, the state of the light beam emitted from the optical element or optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. An eccentricity measuring method or measuring machine for an optical element or an optical system, or a measured one, characterized in that the amount of eccentricity is obtained.
[0074]
[4] Means for causing light to enter the test optical element or test surface in the optical system, and light detection means for detecting light reflected or refracted from the test optical element or test surface in the optical system And an eccentricity measuring device that measures the eccentricity of each surface of the optical element or optical system composed of an optical element or an optical system that guides the light reflected or refracted by the test surface to the light detection means. Alternatively, based on the design value or measurement value of the optical element from the surface to be measured in the optical system to the light detection means or the design value or measurement value of all the optical elements of the optical system, the ray tracing is calculated, and the light state in the light detection means is An optical element or optical system eccentricity measuring method, measuring machine, or measured object, characterized in that the amount of eccentricity of the surface to be measured is determined by calculation so as to be equal to the measured light state.
[0075]
[5] Means for causing a light beam to enter the test optical element or the test surface in the optical system, and a light beam detection means for detecting the light beam reflected or refracted by the test optical element or the test surface in the optical system And an eccentricity measuring device for measuring the eccentricity of each surface of the optical element or optical system constituted by an optical element or an optical system that guides the light beam reflected or refracted by the test surface to the light beam detection means, Or, based on the design value or measurement value of the optical element from the surface to be measured in the optical system to the light beam detection means or the design value or measurement value of all the optical elements of the optical system, the ray tracing calculation is performed, and the state of the light beam in the light beam detection means is An optical element or optical system eccentricity measuring method or measuring machine, or a measured object, characterized in that the amount of eccentricity of the surface to be measured is determined by calculation so as to be equal to the state of the measured light beam.
[0076]
[6] Means for causing a light beam to enter a test surface in the test optical element or optical system, and a light beam detection means for detecting a light beam reflected or refracted from the test surface in the test optical element or optical system And an eccentricity measuring device that measures the eccentricity of each surface of the optical element or optical system composed of an optical element or an optical system that guides the light beam reflected or refracted by the test surface to the light beam detecting means, Alternatively, based on the design value or measurement value of the optical element from the surface to be measured in the optical system to the light beam detecting means or the design values or measured values of all the optical elements of the optical system, the ray tracing calculation is performed, and the state of the light beam in the light beam detecting means is An optical element or optical system eccentricity measuring method or measuring machine, or a measured object, characterized in that the amount of eccentricity of the surface to be measured is determined by calculation so as to be equal to the state of the measured light beam.
[0077]
[7] Optical element or optical system eccentricity measuring method, wherein real ray tracing is performed by optical element or optical system including manufacturing error of optical element or optical system to be measured or optical element or optical system of measuring instrument Or a measuring machine or a measured one.
[0078]
[8] An optical element or optical system eccentricity measuring method characterized by measuring an amount of fluctuation in an optical element or an optical system of a measuring machine and performing real ray tracing with the optical element or optical system in consideration of the quantity of fluctuation. Measuring machine or measured.
[0079]
[9] Measure the amount of decentration by measuring one surface from the front surface of the optical element or optical system, and on the next surface, perform a real ray trace with the optical element or optical system including the decentration amount obtained previously, An optical element or optical system eccentricity measuring method, measuring machine, or measured one characterized by determining an eccentricity amount.
[0080]
[10] The optical element according to any one of the above items 1 to 3, wherein a solution process of an equation in which the measured value is a target value and the amount of eccentricity of the surface to be obtained is an unknown is performed using a real ray trace. Optical system eccentricity measuring method or measuring machine or measured one.
[0081]
[11] A method for solving an equation in which an amount of eccentricity of a plurality of surfaces or lens groups based on a target value, an arbitrary position, or an arbitrary axis is an unknown is performed using a real ray trace. The optical element or optical system eccentricity measuring method or measuring instrument according to any one of 1 to 3 above, or a measured object.
[0082]
[12] The optical element or the optical system eccentricity measuring method or measuring machine or the measured one according to the above 10 or 11, wherein an optimization process is used for calculating the unknown.
[0083]
[13] The optical element or optical system eccentricity measuring method or measuring machine according to the above 12, characterized by using a wave optical point image intensity distribution as an evaluation function.
[0084]
[14] An optical element or an optical system eccentricity measuring method, a measuring machine, or a measuring device, wherein the imaging relationship in measuring the image of the light beam uses either equal magnification imaging or unequal magnification imaging. Things.
[0085]
[15] An optical element or an optical system eccentricity measuring method, measuring machine, or measured object, characterized in that the amount of eccentricity is obtained by an autocollimation method or an unequal magnification method using a local paraxial amount.
[0086]
[16] Using the light intensity distribution or position of the reflected image of the measured index as a target value, the amount of eccentricity of the aspheric surface to be measured is used as a variable, and ray tracing is performed to optimize the amount of eccentricity. An eccentricity measuring method or measuring machine for an optical element or an optical system characterized by obtaining two eccentricity amounts, or a measured one.
[0087]
[17] Using the light intensity distribution or position of the opposite image of the measured index as a target value, the ray tracing is performed using the inclination and the amount of deviation of the aspheric surface to be measured as variables, and the inclination and the amount of deviation are optimized. Thus, a decentration measuring method or measuring instrument for an optical element or an optical system, or a measured one, characterized in that a parameter representing at least one decentration of each element of inclination and deviation amount is obtained.
[0088]
[18] Using the measured light intensity distribution or position of the reflected image of the index as a target value, the inclination and the amount of deviation in two directions perpendicular to the optical axis of the surface to be measured which is an aspheric surface and orthogonal to each other are used as variables. By performing ray tracing and optimizing the inclination and the amount of deviation in two directions orthogonal to the optical axis and orthogonal to each other, at least one of the inclination and the amount of deviation in two directions orthogonal to the optical axis and orthogonal to each other is obtained. An optical element or optical system eccentricity measuring method, measuring machine, or measured one, characterized by obtaining a parameter representing the eccentricity.
[0089]
[19] A light beam is incident on the optical element or optical system to be measured, and the angle between the light beam and the optical axis is changed in various ways, and the position of the light beam reflected or refracted from the test surface with respect to each angle is determined. Detecting and optimizing the amount of eccentricity so that the difference between the position of the light beam measured in all states and the position of the light beam obtained by ray tracing is reduced, thereby obtaining at least one amount of eccentricity. Optical element or optical system eccentricity measuring method or measuring machine or measured one.
[0090]
[20] A light beam is made incident on the optical element or optical system to be measured, and the angle between the light beam and the optical axis is changed in various ways, and the position of the light beam reflected or refracted from the test surface with respect to each angle is determined. By detecting and optimizing the inclination and the amount of deviation so that the difference between the position of the ray measured in all states and the ray position obtained by ray tracing is reduced, at least one eccentricity of the inclination and the amount of deviation is obtained. An optical element or optical system eccentricity measuring method or measuring machine or a measured one characterized by obtaining a parameter to be expressed.
[0091]
[21] A light beam is incident on the optical element or optical system to be measured, and the angle between the light beam and the optical axis is changed variously, and the position of the light beam reflected or refracted from the test surface with respect to each angle is determined. Detect and optimize the tilt and bias in two directions perpendicular to the optical axis and perpendicular to each other so that the difference between the position of the light beam measured in all states and the light beam position obtained by ray tracing is small. Thus, an optical element or an optical system eccentricity measuring method, measuring machine, or measurement is obtained, wherein a parameter representing at least one eccentricity of inclination and deviation in two directions orthogonal to the optical axis and orthogonal to each other is obtained. What was done.
[0092]
[22] In the optical system or in a single aspherical lens, a known inter-plane eccentricity ε between the front surface and the rear surface of the lens _L The amount of front tilt obtained from the measurement of the reflected image of the index ε ₁ ', Back slope ε ₂ 'And ε _L , And front paraxial radius of curvature R ₁ , Rear paraxial radius of curvature R ₂ From the lens thickness T, the inclination ε of the front surface and the rear surface is expressed by the following equation or a mathematically equivalent equation: ₁ And ε ₂ , Bias amount δ ₁ And δ ₂ A decentration measuring method or measuring machine for an optical element or an optical system,
[0093]
δ ₁ = (R ₁ R ₂ + R ₁ T) ε ₁ '/ (R ₂ -R ₁ + T)
-R ₁ R ₂ (Ε ₂ '−ε _L ) / (R ₂ -R ₁ + T) (7)
δ ₂ = R ₁ R ₂ ε ₁ '/ (R ₂ -R ₁ + T)
-(R ₁ R ₂ -R ₂ T) (ε ₂ '−ε _L ) / (R ₂ -R ₁ + T) (8)
ε ₁ = -R ₁ ε ₁ '/ (R ₂ -R ₁ + T)
+ R ₂ (Ε ₂ '−ε _L ) / (R ₂ -R ₁ + T) (9)
ε ₂ = Ε ₁ '+ Ε _L ···(Ten)
[23] In an optical system or in a single spherical or aspherical lens, the decentering between the front surface and the rear surface of the lens is used as a constraint condition, and the decentering is performed using a real ray trace. An optical element or optical system eccentricity measuring method or measuring machine or a measured one characterized by obtaining a parameter to be expressed.
[0094]
[24] An apparent center of curvature of the surface to be measured, that is, an image of the center of curvature of the surface to be measured formed by another surface existing between the surface to be measured and the observation system of the eccentricity measuring machine. The index is projected to a position shifted in the direction along the optical axis from the position, and the amount of deviation of the index image reflected from the lens surface to be measured is calculated, and the index of the index imaged at this position is calculated. An optical element or optical system decentration measuring method, measuring machine, or measured object, characterized by detecting a reflected image of the image.
[0095]
[25] The optical element or optical system eccentricity measuring method or measuring machine according to item 24, wherein the absolute value of the magnification of the reflected image of the index with respect to the projected index is greater than 1.
[0096]
[26] The optical element or optical system eccentricity measuring method, measuring machine, or measured object according to 24 or 25, wherein a real ray trace is used.
[0097]
[27] a light source, means for dividing light from the light source into a plurality of point light source group images, means for projecting the point light source image group in the vicinity of the test surface, and the point light source reflected or refracted by the test surface A detection means for detecting an image group; and a means for guiding the point light source image group reflected or refracted by the test surface to the detection means, and a paraxial ray tracing based on the position of the detected point light source image group Alternatively, an optical element or optical system eccentricity measuring method, measuring machine, or measured object, characterized in that a real ray trace is performed to obtain a parameter representing the eccentricity of the surface to be examined.
[0098]
[28] means for dividing the light transmitted through the optical element or optical system into a plurality of point light source image groups, detection means for detecting the point light source image groups, and means for guiding the point light source image groups to the detection means; A decentering measurement of an optical element or an optical system, wherein paraxial ray tracing or real ray tracing is performed based on the position of the detected point light source image group to obtain a parameter representing the eccentricity of the test surface Method or measuring instrument or measured.
[0099]
[29] A light source, means for dividing light from the light source into a plurality of light beam groups, means for projecting the light beam group in the vicinity of the test surface, and detecting the light beam group reflected or refracted by the test surface Detecting means, and means for guiding the light flux group reflected or refracted by the test surface to the detection means, performing paraxial ray tracing or real ray tracing based on the position of the detected light flux group, and An optical element or optical system eccentricity measuring method, measuring machine, or measured object, characterized by obtaining a parameter representing the eccentricity of the surface to be detected.
[0100]
[30] A device comprising: means for dividing the light transmitted through the optical element or the optical system into a plurality of light flux groups; detection means for detecting the light flux groups; and means for guiding the light flux group to the detection means. Performing paraxial ray tracing or real ray tracing based on the position of the light beam group, and obtaining a parameter representing the eccentricity of the test surface, an optical element or an optical system eccentricity measuring method, measuring machine, or measured thing.
[0101]
[31] The optical element or the eccentricity measuring method or measuring apparatus according to any one of 1 to 30 above, which is intended for an optical system of a zoom lens such as a camera, an endoscope, or a microscope. Or measured.
[0102]
[32] A storage medium in which the processing method according to any one of 1 to 30 is recorded in a machine-readable form.
[0103]
[33] An eccentricity measurement processing apparatus using the processing method according to any one of 1 to 30 above.
[0104]
[34] An optical element or optical system eccentricity measuring method, measuring machine, or measured one, wherein the computer for controlling the measuring machine and the computer for performing the real ray tracing are the same.
[0105]
[35] Light is incident on the optical element or optical system to be measured, the state of the light emitted from the optical element or optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. A physical quantity measuring method or measuring machine for an optical element or an optical system characterized by obtaining a physical quantity of the optical element.
[0106]
[36] A light beam is incident on the optical element or optical system to be measured, the state of the light beam emitted from the optical element or optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. A physical quantity measuring method or measuring machine for an optical element or an optical system characterized by obtaining a physical quantity of the optical element.
[0107]
[37] A light beam is incident on the optical element or optical system to be measured, the state of the light beam emitted from the optical element or the optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. A physical quantity measuring method or measuring machine for an optical element or an optical system characterized by obtaining a physical quantity of the optical element.
[0108]
[38] Means for causing light to enter the test optical element or test surface in the optical system, and light detection means for detecting light reflected or refracted by the test optical element or test surface in the optical system And a physical quantity measuring device for measuring a physical quantity of each surface of the optical element or optical system composed of an optical element or an optical system that guides the light reflected or refracted by the test surface to the light detection means, wherein the optical element Alternatively, based on the design value or measurement value of the optical element from the surface to be measured in the optical system to the light detection means or the design value or measurement value of all the optical elements of the optical system, the ray tracing is calculated, and the light state in the light detection means is A physical quantity measuring method or measuring instrument for an optical element or an optical system, or a measured one, characterized in that a physical quantity of a test surface that is equal to the measured light state is calculated.
[0109]
[39] Means for causing a light beam to enter the test optical element or the test surface in the optical system, and a light beam detection means for detecting the light beam reflected or refracted by the test optical element or the test surface in the optical system A physical quantity measuring device for measuring a physical quantity of each surface of an optical element or an optical system composed of an optical element or an optical system that guides the light beam reflected or refracted by the test surface to the light beam detection means, Or, based on the design value or measurement value of the optical element from the surface to be measured in the optical system to the light beam detection means or the design value or measurement value of all the optical elements of the optical system, the ray tracing calculation is performed, and the state of the light beam in the light beam detection means is A physical quantity measuring method or measuring instrument for an optical element or an optical system, or a measured one, characterized in that a physical quantity of a surface to be measured which is equal to the measured light state is calculated.
[0110]
[40] Means for causing a light beam to enter a test surface in the test optical element or optical system, and a light beam detection means for detecting a light beam reflected or refracted from the test surface in the test optical element or optical system A physical quantity measuring device for measuring a physical quantity of each surface of an optical element or an optical system composed of an optical element or an optical system that guides a light beam reflected or refracted by the test surface to the light beam detecting means; Alternatively, based on the design value or measurement value of the optical element from the surface to be measured in the optical system to the light beam detecting means or the design values or measured values of all the optical elements of the optical system, the ray tracing calculation is performed, and the state of the light beam in the light beam detecting means is A physical quantity measuring method or measuring instrument for an optical element or an optical system, or a measured one, characterized in that a physical quantity of a surface to be measured which is equal to a state of a measured light beam is calculated.
[0111]
[41] A physical quantity measurement method for an optical element or an optical system, wherein real ray tracing is performed with an optical element or an optical system including manufacturing errors of the optical element or optical system to be measured or the optical element or optical system of a measuring instrument. Or a measuring machine or a measured one.
[0112]
[42] A method for measuring a physical quantity of an optical element or an optical system, which measures an amount of fluctuation in an optical element or an optical system of a measuring machine and performs real ray tracing with the optical element or optical system taking the fluctuation amount into account. Measuring machine or measured.
[0113]
[43] A physical quantity is obtained by measuring one surface at a time from the front surface of the optical element or optical system. On the next surface, a real ray trace is performed with the optical element or optical system including the physical quantity obtained previously, and the physical quantity of the surface is calculated. A physical quantity measuring method or measuring machine for an optical element or an optical system characterized by being obtained or measured.
[0114]
[44] The optical element or the optical device according to any one of [35] to [37], wherein a solution process of an equation using the measured value as a target value and the physical quantity of the surface to be obtained as an unknown is performed using a real ray trace. System physical quantity measuring method or measuring machine or measured.
[0115]
[45] A method for solving an equation using a physical quantity of a plurality of surfaces or lens groups based on a target value, an arbitrary position or an arbitrary axis as an unknown and performing measurement processing using a real ray trace. 38. A physical quantity measuring method or measuring instrument of an optical element or an optical system according to any one of 35 to 37 above, or a measured one.
[0116]
[46] The physical quantity measuring method or measuring instrument of an optical element or optical system as described in 44 or 45 above, wherein an optimization process is used for calculating the unknown.
[0117]
[47] The physical quantity measuring method or measuring machine of an optical element or optical system as described in 46 above, wherein the wave optical point image intensity distribution is used as an evaluation function.
[0118]
[48] An optical element or an optical system physical quantity measuring method, a measuring machine, or a measuring device, characterized in that the imaging relationship in measuring an image of a light beam uses either equal magnification imaging or unequal magnification imaging. Things.
[0119]
[49] A light beam is incident on the optical element or optical system to be measured, and the angle between the light beam and the optical axis is changed variously, and the position of the light beam reflected or refracted from the test surface with respect to each angle is determined. An optical element characterized in that at least one physical quantity is obtained by optimizing the physical quantity so as to reduce the difference between the position of the light ray detected in all states and the light ray position obtained by ray tracing. Or a physical quantity measuring method or measuring instrument of an optical system or a measured one.
[0120]
[50] A light beam is incident on the optical element or optical system to be measured, and the angle between the light beam and the optical axis is changed variously, and the position of the light beam reflected or refracted from the test surface is determined for each angle. By detecting and optimizing the inclination and the amount of deviation so that the difference between the position of the ray measured in all states and the ray position obtained by ray tracing is reduced, at least one physical quantity of the inclination and the amount of deviation is obtained. A method for measuring a physical quantity of an optical element or an optical system, a measuring machine, or a measured object characterized by obtaining a parameter to be expressed.
[0121]
[51] A light beam is incident on the optical element or optical system to be measured, and the angle between the light beam and the optical axis is changed variously, and the position of the light beam reflected or refracted from the test surface with respect to each angle is determined. Detect and optimize the tilt and bias in two directions perpendicular to the optical axis and perpendicular to each other so that the difference between the position of the light beam measured in all states and the light beam position obtained by ray tracing is small. To obtain a parameter representing at least one physical quantity of a tilt and a deviation amount in two directions orthogonal to the optical axis and orthogonal to each other, or a physical quantity measuring method or measuring instrument or measurement of an optical element or optical system What was done.
[0122]
[52] An apparent center of curvature of the surface to be measured, that is, an image of the center of curvature of the surface to be measured formed by another surface existing between the surface to be measured and the observation system of the physical quantity measuring machine. The index is projected to a position shifted in the direction along the optical axis from the position, and the amount of deviation of the index image reflected from the lens surface to be measured is calculated, and the index of the index imaged at this position is calculated. A method for measuring a physical quantity of an optical element or an optical system, a measuring machine, or a measured object, characterized by detecting a reflected image of the image.
[0123]
[53] The physical quantity measuring method or measuring instrument of an optical element or optical system according to the above 52, wherein the absolute value of the magnification of the reflected image of the index with respect to the projected index is greater than 1.
[0124]
[54] A physical quantity measuring method or measuring instrument of an optical element or an optical system according to the above 52 or 53, wherein a real ray trace is used.
[0125]
[55] a light source, means for dividing light from the light source into a plurality of point light source group images, means for projecting the point light source image group in the vicinity of the test surface, and the point light source reflected or refracted by the test surface A detection means for detecting an image group; and a means for guiding the point light source image group reflected or refracted by the test surface to the detection means, and a paraxial ray tracing based on the position of the detected point light source image group Alternatively, a real ray tracing is performed, and a parameter representing the physical quantity of the surface to be measured is obtained.
[0126]
[56] means for dividing light transmitted through the optical element or optical system into a plurality of point light source image groups, detection means for detecting the point light source image groups, and means for guiding the point light source image groups to the detection means; A physical quantity measurement of an optical element or an optical system, characterized in that paraxial ray tracing or real ray tracing is performed based on the position of the detected point light source image group, and a parameter representing the physical quantity of the test surface is obtained. Method or measuring instrument or measured.
[0127]
[57] A light source, means for dividing light from the light source into a plurality of light beam groups, means for projecting the light beam group in the vicinity of the test surface, and detecting the light beam group reflected or refracted by the test surface Detecting means, and means for guiding the light flux group reflected or refracted by the test surface to the detection means, performing paraxial ray tracing or real ray tracing based on the position of the detected light flux group, and A method for measuring a physical quantity of an optical element or an optical system, a measuring machine, or a measured one, wherein a parameter representing a physical quantity of a surface to be measured is obtained.
[0128]
[58] A device comprising: means for dividing light transmitted through the optical element or optical system into a plurality of light beam groups; detection means for detecting the light beam groups; and means for guiding the light beam group to the detection means. A paraxial ray tracing or real ray tracing is performed based on the position of the light beam group, and a parameter representing the physical quantity of the surface to be measured is obtained. thing.
[0129]
[59] The optical element or the physical quantity measuring method or measuring apparatus according to any one of 35 to 58, which is intended for an optical system of a zoom lens such as a camera, an endoscope, or a microscope Or measured.
[0130]
[60] A physical quantity measurement processing apparatus using the processing method described in any one of 35 to 58 above.
[0131]
[61] A method for measuring a physical quantity of an optical element or an optical system, a measuring machine, or a measured object, wherein the computer for controlling the measuring machine and the computer for performing the real ray tracing are the same.
[0132]
[62] Light is incident on the optical element or optical system to be measured, the state of the light emitted from the optical element or optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. A refractive index distribution type measuring method or measuring instrument for an optical element or an optical system, or a measured one.
[0133]
[63] A light beam is incident on the optical element or optical system to be measured, the state of the light beam emitted from the optical element or optical system is measured, and the optical element or optical system is measured by using a real ray trace from the measured value. A refractive index distribution type measuring method or measuring instrument for an optical element or an optical system, or a measured one.
[0134]
[64] A light beam is incident on the optical element or optical system to be measured, the state of the light beam emitted from the optical element or the optical system is measured, and a real ray trace is used from the measured value, whereby the optical element or the optical system is measured. A refractive index distribution type measuring method or measuring instrument for an optical element or an optical system, or a measured one.
[0135]
[65] Means for causing light to enter the test optical element or the test surface in the optical system, and light detection means for detecting light reflected or refracted by the test optical element or the test surface in the optical system And a refractive index distribution type measurement for measuring the refractive index distribution type of each surface of the optical element or optical system composed of an optical element or an optical system that guides the light reflected or refracted by the test surface to the light detection means. In the machine, calculation of ray tracing is performed based on the design value or measurement value of the optical element or all optical elements of the optical system from the measured surface in the optical element or optical system to the light detection means, and the light detection is performed. A refractive index distribution type measuring method or measuring instrument for an optical element or an optical system, characterized in that a refractive index distribution type of a surface to be measured is calculated so that the light state in the means is equal to the measured light state Or measured.
[0136]
[66] Means for making a light beam incident on a test surface in the test optical element or optical system, and a light beam detection means for detecting a light beam reflected or refracted by the test surface in the test optical element or optical system And a refractive index distribution type measurement for measuring the refractive index distribution type of each surface of the optical element or optical system composed of an optical element or an optical system that guides the light beam reflected or refracted by the test surface to the light detection means. In the machine, ray tracing is calculated based on design values or measurement values of all optical elements in the optical element or optical system from the measured surface in the optical element or optical system to the light detection means, and the light detection is performed. A refractive index distribution type measuring method or measuring instrument for an optical element or an optical system, characterized in that the refractive index distribution type of the surface to be measured is calculated so that the state of the light beam in the means becomes equal to the state of the measured light beam Or measured.
[0137]
[67] Means for causing a light beam to be incident on a test surface in the test optical element or optical system, and light flux detection means for detecting a light beam reflected or refracted from the test surface in the test optical element or optical system And a refractive index distribution type measurement for measuring the refractive index distribution type of each surface of the optical element or optical system composed of an optical element or an optical system for guiding the light beam reflected or refracted by the test surface to the light beam detecting means. In the machine, ray tracing is calculated based on the design values or measured values of the optical elements or all optical elements of the optical system from the measured surface in the optical element or optical system to the luminous flux detection means, and the luminous flux detection is performed. A refractive index distribution type measuring method or measuring instrument for an optical element or an optical system, characterized in that a refractive index distribution type of a surface to be measured is obtained by calculation so that the state of the light beam in the means becomes equal to the state of the measured light beam Or measured.
[0138]
[68] Refractive index distribution of optical element or optical system characterized in that real ray tracing is performed by optical element or optical system including manufacturing error of optical element or optical system to be measured or optical element or optical system of measuring machine Mold measuring method or measuring machine or measured.
[0139]
[69] A refractive index distribution type of an optical element or an optical system, characterized by measuring a fluctuation amount in an optical element or an optical system of a measuring instrument, and performing a real ray trace with the optical element or the optical system in consideration of the fluctuation amount Measuring method or measuring instrument or measured item.
[0140]
[70] Refractive index distribution type is obtained by measuring one surface from the front surface of the optical element or optical system, and real ray tracing is performed on the next surface with the optical element or optical system including the refractive index distribution type obtained previously. A refractive index distribution type measuring method or measuring instrument of an optical element or an optical system characterized by obtaining a refractive index distribution type of the surface.
[0141]
[71] The optical system as set forth in any one of [62] to [64], wherein a solution process of an equation using the measured value as a target value and an unknown refractive index distribution type of a surface to be obtained is performed using a real ray trace. Refractive index distribution type measuring method or measuring instrument of element or optical system or measured one.
[0142]
[72] A process for solving an equation with a refractive index distribution type of a plurality of surfaces or lens groups based on a target value, an arbitrary position, or an arbitrary axis as an unknown is performed using a real ray trace. 65. The optical element or optical system refractive index distribution type measuring method or measuring instrument according to any one of the above 62 to 64, or a measured one.
[0143]
[73] The refractive index distribution type measuring method or measuring instrument of an optical element or an optical system according to the above 71 or 72, wherein an optimization process is used for calculating the unknown.
[0144]
[74] The optical element or the refractive index distribution type measuring method or measuring instrument of an optical system or optical system as described in 73 above, wherein the wave optical point image intensity distribution is used as an evaluation function.
[0145]
[75] An optical element or a refractive index distribution type measuring method or measuring instrument for an optical system, wherein an imaging relationship in measuring an image of a light beam uses either equal-magnification imaging or unequal-magnification imaging Or measured.
[0146]
[76] A light beam is incident on the optical element or optical system to be measured, and the angle formed by this light beam and the optical axis is changed variously. The position of the light beam reflected or refracted from the test surface with respect to each angle is determined. Detect at least one refractive index distribution type by optimizing the refractive index distribution type so that the difference between the position of the light ray measured in all states and the ray position obtained by ray tracing is reduced. An optical element or a refractive index distribution-type measuring method or measuring machine or a measured one of an optical system.
[0147]
[77] A light beam is incident on the optical element or optical system to be measured, and the angle between the light beam and the optical axis is changed variously, and the position of the light beam reflected or refracted from the test surface with respect to each angle is determined. By detecting and optimizing the tilt and the amount of deviation so that the difference between the position of the ray measured in all states and the ray position obtained by ray tracing is reduced, at least one refractive index of the inclination and the amount of deviation A refractive index distribution type measuring method or measuring machine for an optical element or an optical system characterized by obtaining a parameter representing a distribution type, or a measured one.
[0148]
[78] A light beam is incident on the optical element or optical system to be measured, and the angle formed between the light beam and the optical axis is changed in various ways, and the position of the light beam reflected or refracted from the test surface with respect to each angle is determined. Detect and optimize the tilt and bias in two directions perpendicular to the optical axis and perpendicular to each other so that the difference between the position of the light beam measured in all states and the light beam position obtained by ray tracing is small. A refractive index distribution type measurement of an optical element or an optical system, characterized in that a parameter representing at least one refractive index distribution type of two directions of inclination and deviation perpendicular to the optical axis and orthogonal to each other is obtained. Method or measuring instrument or measured.
[0149]
[79] The apparent center of curvature of the surface to be measured, that is, the center of curvature of the surface to be measured formed by another surface existing between the surface to be measured and the observation system of the gradient index measuring instrument The index is projected to a position shifted from the position of the image in the direction along the optical axis, the amount of deviation of the index image reflected from the lens surface to be measured is calculated, and the image is formed at this position. A reflection index distribution type measuring method or measuring instrument of an optical element or an optical system, or a measured one, wherein a reflected image of an index image is detected.
[0150]
[80] The optical element or the refractive index distribution type measuring method or measuring machine of the optical element or optical system according to 79, wherein the absolute value of the magnification of the reflected image of the index with respect to the projected index is greater than 1. .
[0151]
[81] The refractive index distribution type measuring method or measuring instrument of an optical element or optical system as described in 79 or 80, wherein a real ray trace is used, or a measured one.
[0152]
[82] a light source, means for dividing light from the light source into a plurality of point light source group images, means for projecting the point light source image group in the vicinity of the test surface, and the point light source reflected or refracted by the test surface A detection means for detecting an image group; and a means for guiding the point light source image group reflected or refracted by the test surface to the detection means, and a paraxial ray tracing based on the position of the detected point light source image group Alternatively, a real ray tracing is performed, and a parameter representing the refractive index distribution type of the surface to be measured is obtained.
[0153]
[83] means for dividing the light transmitted through the optical element or optical system into a plurality of point light source image groups, detection means for detecting the point light source image groups, and means for guiding the point light source image groups to the detection means; An optical element or an optical system characterized by performing paraxial ray tracing or real ray tracing based on the position of the detected point light source image group and obtaining a parameter representing the refractive index distribution type of the surface to be examined Refractive index distribution type measuring method or measuring instrument or measured one.
[0154]
[84] a light source, means for dividing the light from the light source into a plurality of light beam groups, means for projecting the light beam group in the vicinity of the test surface, and detecting the light beam group reflected or refracted by the test surface Detecting means, and means for guiding the light flux group reflected or refracted by the test surface to the detection means, performing paraxial ray tracing or real ray tracing based on the position of the detected light flux group, and A method for measuring a refractive index distribution type of an optical element or an optical system, a measuring machine, or a measured one, characterized in that a parameter representing a refractive index distribution type of an inspection surface is obtained.
[0155]
[85] A device comprising: means for dividing the light transmitted through the optical element or optical system into a plurality of light flux groups; detection means for detecting the light flux groups; and means for guiding the light flux group to the detection means. Performing paraxial ray tracing or real ray tracing based on the position of the light beam group to obtain a parameter representing the refractive index distribution type of the test surface, or a refractive index distribution type measuring method for an optical element or optical system, Measuring machine or measured.
[0156]
[86] The optical element or the refractive index distribution type measuring method for an optical system according to any one of the above 62 to 85, which is intended for an optical system of a zoom lens such as a camera, endoscope or microscope Or a measuring machine or a measured one.
[0157]
[87] A gradient index measurement processing apparatus using the processing method according to any one of 62 to 85.
[0158]
[88] A refractive index distribution type measuring method or measuring instrument for an optical element or optical system, or a measured one, wherein the computer for controlling the measuring instrument and the computer for performing the real ray tracing are the same.
[0159]
【The invention's effect】
As is apparent from the above description, in the physical quantity measuring method of the optical element or optical system of the present invention, the state of the light emitted from the optical element or optical system to be measured is measured, and the real ray trace is obtained from the measured value. Since the physical quantity is obtained by use, it is possible to obtain a parameter representing the physical quantity of the optical system composed of a single element or a combination of optical elements with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a real ray trace used in an eccentricity measuring method of the present invention.
FIG. 2 is a block diagram of a processing apparatus that performs an optical element or optical system eccentricity measuring method according to an embodiment of the present invention.
FIG. 3 is a flowchart of processing performed by the apparatus of FIG.
4 is a flowchart showing details of an eccentricity amount calculation process in FIG. 3; FIG.
5 is a flowchart of processing for performing the eccentricity calculation processing of FIG. 4 in order from the front surface to the rear surface one by one.
FIG. 6 is a diagram illustrating an example of a measuring machine for measuring a shake amount of a reflected image from a reference axis.
FIG. 7 is a diagram for explaining a state in which a shake amount from a reference axis of a reflected image is measured by an autocollimator.
FIG. 8 is a diagram for explaining an example of a real ray trace for calculating an image point position;
FIG. 9 is a diagram for explaining an example of a real ray trace for calculating a gravity center position of a light beam and a spread of the light beam;
FIG. 10 is a diagram illustrating an example of the definition of the amount of eccentricity of a lens surface, a single lens, and a lens group.
FIG. 11 is a diagram showing an embodiment in which the real ray tracing method of the present invention is applied to an aspheric eccentricity measuring device using the oblique incidence method.
FIG. 12 is a diagram showing definitions of eccentric amounts εr, δr, εθ, and δθ.
FIG. 13 is a diagram showing an example of a centering microscope using the real ray tracing method of the present invention.
FIG. 14 is a diagram showing an arrangement for obtaining a decentering amount by creating a point light source image group with a microlens array according to the present invention.
15 is a diagram illustrating an example of an image of each point light source in FIG.
FIG. 16 is a diagram showing an application example of the Shack-Hartmann method according to the present invention.
FIG. 17 is a diagram for explaining a state in which an unmagnified image is created by an autocollimator and a shake amount is measured according to the present invention.
FIG. 18 is a diagram for explaining an embodiment for measuring, evaluating, and analyzing a refractive index distribution of an optical element using a real ray trace according to the present invention.
[Explanation of symbols]
1. Arithmetic processing device
2 ... Display device
3 ... Input device
4. Storage device
5. External media
6 ... Printer
7 ... LAN
8 ... Measuring machine
9 ... Optical element measuring machine
10. Optical system design device
51 ... surface to be measured
52 ... Light source (index)
53 ... Collimator lens
54. Image plane
61 ... Test surface
62 ... Microlens array
63 ... Projection lens
64 ... half mirror
65: Image sensor
71: Optical element or optical system to be tested
72 ... Collimating lens
73 ... Microlens array
74 ... Relay lens
75: Image sensor
81 ... He-Ne laser
82 ... Beam splitter
83: Optical element to be tested
84: Reference optical system
85 ... Beam splitter
86 ... Screen
102: Optical system
103 ... Projection lens
105 ... Microscope objective lens
106 ... Zoom lens
107 ... CCD camera
111 ... Mirror
115: Beam splitter
120 ... Aspherical surface
121 ... Aspherical lens to be examined
134 ... Triangular prism
141: Eccentricity measuring machine
149 ... Signal processing circuit
150 ... Calculator
151 ... TV monitor
160 ... Centering microscope
161: Light source
162 ... pinhole
163 ... Daylighting lens
164 ... non-surface inspection
165 ... Test lens
166: Imaging lens
167 ... Half mirror
168 ... Focus plate
169 ... Eyepiece
170 ... eyes
171 ... Variable power system
172, 173, 174 ... optical surfaces
201 ... Semiconductor laser
202 ... Optical system for measurement
203 ... Lens to be measured
204: Beam splitter
205: Image rotator
206: Optical system for setting a reference axis
207 ... CCD camera
208 ... Monitor TV
209 ... CRT
210 ... arithmetic processing unit

Claims

With respect to the optical element or optical system to be measured, a light beam having variously changed angles formed with the optical axis of the optical element or optical system to be measured is incident,
For each angle, measure the characteristics of the light beam emitted from the measured optical element or optical system and imaged on the image plane by a condensing optical system,
Real ray tracing is performed for each angle,
The amount of eccentricity of the measured optical element or optical system in the real ray trace so that the difference between the characteristic of the measured light ray and the characteristic of the light ray obtained by the real ray trace is reduced at all the respective angles. Alternatively, an optical element characterized in that at least one optimized amount of decentration of the optical element to be measured or optical system is obtained by changing an inclination and a deviation amount of a lens surface of the optical element to be measured or optical system. Or the physical quantity measuring method of an optical system.

The method of measuring a physical quantity of an optical element or an optical system according to claim 1, wherein the characteristic of the light beam is an image point position of the light beam.

The method for measuring a physical quantity of an optical element or an optical system according to claim 1, wherein the characteristic of the light beam is a light intensity distribution at an image point position of the light beam.

2. The physical quantity measuring method of an optical element or an optical system according to claim 1, wherein the characteristic of the light beam is a wavefront aberration of the light beam.