JP2004205478A - Three-dimensional coordinate measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To find a face shape, a relative positional relation between a plurality of faces and the like, based on an optical element of an inspection object or its edge type. <P>SOLUTION: This three-dimensional coordinate measuring method has a process for measuring respectively a three-dimensional face shape and its edge shape in every face in the inspection object O constituted of the plurality of faces S1, S2, and for finding the relative positional relation between the plurality of faces S1, S2 by correlating measured values of the common edges E. Relative positions of design coordinate systems (local coordinate systems) of the respective inspected faces with respect to outer shapes are clearly found by this method, and the relative positional relation of the local coordinate systems in the plurality of faces are made clear thereby. A relative eccentric quantity in the plurality of faces is found thereby to be reflected to factor elucidation, correction and the like for optical performance deterioration. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

ここで、（ａ）式の第１項は球面項、第２項は自由曲面項である。
【００３１】
球面項中、
ｃ：頂点の曲率
ｋ：コーニック定数（円錐定数）
ｒ＝√（Ｘ^２ ＋Ｙ^２ ）
である。
【００３２】
自由曲面項は、

ただし、Ｃ_ｊ （ｊは２以上の整数）は係数である。
【００３３】
上記自由曲面は、一般的には、Ｘ−Ｚ面、Ｙ−Ｚ面共に対称面を持つことはないが、Ｘの奇数次項を全て０にすることによって、Ｙ−Ｚ面と平行な対称面が１つだけ存在する自由曲面となる。また、Ｙの奇数次項を全て０にすることによって、Ｘ−Ｚ面と平行な対称面が１つだけ存在する自由曲面となる。
【００３４】
次に、複数の面の境界からなるエッジを、そのエッジを構成する面毎に測定し、それらを組み合わせることで、エッジを構成する複数の面の相対的な偏心を算出する方法について説明する。ここでは、例えば、自由曲面や、シリンドリカル面、アナモルフィック面、非球面、球面が複数面相互に偏心して配置されることで構成されるプリズム等の光学素子の各面の設計座標系（ローカル座標系）の相対的な位置関係を求める場合を示す。
【００３５】
図７を参照にして、被検物（プリズム）Ｏの１つのエッジＥを共有する被検面Ｓ１、Ｓ２の偏心量を算出する方法について説明する。図７（ａ）は被検物Ｏの被検面Ｓ１に対して光プローブ２を走査することにより、その面の形状、エッジの形状を測定する様子を示す斜視図、図７（ｂ）は被検面Ｓ１の上面図、図７（ｃ）は被検面Ｓ２に対して光プローブ２を走査することにより、その面の形状、エッジの形状を測定する様子を示す斜視図、図７（ｄ）は被検面Ｓ２の上面図である。
【００３６】
まず、図６で示したように、各被検面Ｓ１、Ｓ２毎にエッジＥの形状測定値と有効エリアＢ１、Ｂ２内の面形状測定値とを同じ非接触３次元測定機を用いて同じ測定座標系で測定し、その面形状データを各被検面Ｓ１、Ｓ２の設計値に当てはめるフィッティングを行い、その座標変換をエッジＥの測定データにも行うことで、被検面Ｓ１、Ｓ２を表すローカル座標系Ａ１、Ａ２に対するエッジＥの位置を求める。
【００３７】
さらに、各面毎に測定したエッジＥの各データが一致するように座標変換を行う。このとき、一方の面のエッジ測定値を固定とし、他方のエッジ測定値を偏心、シフトさせることで、面エッジが重なるようにしてもよい。また、解析には両エッジの測定値が略同一曲線上に乗るように最小２乗法を利用してもよい。
【００３８】
この解析より得られた座標変換を、被検面Ｓ１、Ｓ２を表すローカル座標系Ａ１、Ａ２に対しても実行することで、図８に示すような、複数の面Ｓ１、Ｓ２におけるローカル座標系Ａ１、Ａ２の相対的な位置関係を明確にすることが可能となる。なお、図８では、エッジＥを構成する被検面が２面のみの例を示したが、これに限定するものではなく、被検面が３面以上のローカル座標系の相対位置も同様の手法により求めることが可能となる。これらの手法により、複数の面における相対的な偏心量が分かるため、光学性能劣化の要因解明、修正等に反映させることが可能となる。
【００３９】
次に、図９に示すように、共通のエッジＥを共有する２つの被検面Ｓ１、Ｓ２の偏心量を、被検物Ｏの素子に固定した基準となる素子（基準ブロック）Ｄを用いて、算出する方法について説明する。図９（ａ）は被検物Ｏの被検面Ｓ１と基準ブロックＤの１つの基準面Ｈに対して光プローブ２を走査することにより、被検面Ｓ１の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図、図９（ｂ）は被検面Ｓ１の上面図、図９（ｃ）は被検面Ｓ２と基準ブロックＤの他の基準面Ｈに対して光プローブ２を走査することにより、被検面Ｓ２の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図、図９（ｄ）は被検面Ｓ２の上面図である。
【００４０】
被検物Ｏは基準ブロックＤと保持具Ｃで一体に固定して保持されており、基準ブロックＤの各基準面Ｈとそれに対応した各被検面Ｓ１、Ｓ２の形状をそれぞれ同じ非接触３次元測定機を用いて同じ測定座標系で測定できるようにする。
【００４１】
なお、各被検面Ｓ１、Ｓ２の面形状データは、それぞれ各被検面Ｓ１、Ｓ２の設計値に当てはめるフィッティングを行うことで、被検面Ｓ１、Ｓ２を表すローカル座標系ローカル座標系Ａ１、Ａ２の位置を求めておく。
【００４２】
また、ローカル座標系算出の際には、各被検面の設計形状を座標変換して、面形状データと座標変換した各設計形状を重ね合わせた際に、残差が最小となるような座標変換パラメータを求める最適化の解析行ってもよい。
【００４３】
基準ブロックＤの形状は、被検物Ｏの各被検面Ｓ１、Ｓ２の測定と同時に少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点の位置を測定できるように構成することが望ましい。このとき、測定に用いた少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点は、それらの測定結果より基準ブロックＤの各基準面Ｈの位置を定義できるようなものとする必要がある。さらに、少なくとも各測定面Ｈと同時に測定するエッジｅの角度や長さは、予め高精度に測定しておき、既知のものとしておき、これらの既知のデータから測定値で定義される各基準面Ｈの相対的な位置が分かるようにしておく。
【００４４】
なお、基準ブロックＤの形状は、例えば、被検物Ｏの形状に合わせて被検面Ｓ１、Ｓ２を平面で近似した構成の多面体の形状であってもよい。このとき、各被検面Ｓ１、Ｓ２の設計値のローカル座標系Ａ１、Ａ２で定義される平面で構成した多面体としてもよい。基準ブロックＤを平面で構成する場合、測定が高精度かつ簡略化でき、解析も他の曲面に対して容易となる。また、このような形状にすることにより、基準ブロックＤの各基準面Ｈとそれに対応した各被検面Ｓ１、Ｓ２を略水平に保持することが可能となり、同じ測定座標系を用いて、それぞれ容易に測定することが可能となる。
【００４５】
次に、測定方法について説明する。まず、図９で示すように、各被検面Ｓ１、Ｓ２毎に基準ブロックＤのエッジｅの形状測定値と、被検物Ｏの有効エリアＢ１、Ｂ２内の面形状測定値とを、同じ非接触３次元測定機を用いて同じ測定座標系で測定する。また、後述するように、有効エリア以外の領域に、被検面上のローカル座標系で示した場合の座標位置が既知であるマークｖが加工されている場合には、同様に、同じ測定座標系で測定する。
【００４６】
なお、例えば測定機の関係で、被検面Ｓ１、Ｓ２を上に向ける必要がある場合、図９（ａ）〜（ｄ）に示すように、各面の測定毎に被検物Ｏを回転させて保持する必要がある。そのため、図示しない回転機構を用いて、被検物Ｏと基準ブロックＤを所望の方向に回転させて固定することになる。このとき、被検物Ｏと基準ブロックＤは、回転によっても相対的な位置関係が変化しないようにする。
【００４７】
基準ブロックＤは、既知の測定値に対応させて、基準ブロックＤの測定値より基準面位置を求めることができるような項目の測定を行う。図９では、各基準面Ｈ毎に２つのエッジｅを測定した例を示している。これらのデータから、基準ブロックＤの基準面Ｈの相対位置を求めることが可能となる。
【００４８】
例えば、被検面Ｓ１とＳ２の各基準面Ｈのエッジの測定で、測定するエッジは、基準ブロックＤを構成する基準面の境界となる稜線を含むものとし、さらに異なるエッジ部を測定することで、各基準面毎に稜線の位置と基準面を表す平面の位置を求めるようにしてもよい。ここで、稜線の位置とは、稜線が示す基準面の辺の少なくとも１つの頂点の位置と、稜線を表す直線式を導出した結果を意味する。頂点を算出するためには、基準面内で頂点をなす２つのエッジの形状の測定結果から交点を求めてもよい。また、例えば、基準面の頂点との位置関係が既知である点を測定できるようにしておき、その点の測定結果と稜線となるエッジの測定結果から、同様に稜線の位置と基準面を表す平面の位置を求めるようにしてもよい。このとき、解析にはエッジの測定値が略直線上になるように、最小２乗法等を利用してもよい。さらに、導出した平面と基準ブロックＤの既知の測定値（辺の長さや辺と辺の角度）を対応させて、各基準面の位置を求めることが可能となる。ただし、各基準面位置として、平面の位置と稜線の位置が分かれば、後述する各被検面Ｓ１、Ｓ２の相対値の導出は可能となる。
【００４９】
さらに、同じ測定座標系で被検面Ｓ１、Ｓ２の形状を測定することにより、基準面Ｈと被検面Ｓ１、Ｓ２の相対的な位置を各被検面Ｓ１、Ｓ２毎に把握することが可能となる。
【００５０】
なお、後述するように、有効エリア以外の領域に、被検面上のローカル座標系で示した場合の座標位置が既知であるマークｖが加工されている場合には、面形状と同様に、マーク位置を測定することで、基準面Ｈと被検面Ｓ１、Ｓ２上にあるマークｖの相対的な位置を、各被検面Ｓ１、Ｓ２毎に把握することが可能となる。
【００５１】
さらに、基準ブロックＤを構成する基準面Ｈの既知のデータに対応させて、各基準面Ｈの測定値により求められた各面の位置を変換し、各面の相対的な位置関係を合わせる。このとき、シフトや回転といった座標変換を行う必要がある。
【００５２】
例えば、同一の稜線を含む各基準面Ｈの測定結果からそれぞれ導出した稜線の位置が空間的に一致するように座標変換を行い、これにより空間的に一致した稜線を回転軸として、稜線を含む各平面を、基準素子の既知の値（基準素子で同じ稜線を構成する各基準面のなす角度） と対応するように、回転の座標変換を行うパラメータを算出してもよい。これにより、基準ブロックＤの既知の角度を用いて、各基準面Ｈの相対位置を求めることが可能となる。
【００５３】
これらの変換を各基準面と同じ測定座標系で測定した各被検面Ｓ１、Ｓ２の形状測定データに対しても行うことで、各被検面Ｓ１、Ｓ２の相対的な位置を算出することが可能となる。
【００５４】
また、後述するように、有効エリア以外の領域に、被検面上のローカル座標系で示した場合に座標位置が既知であるマークｖが加工されている場合には、面形状と同様に、各被検面と同じ測定座標系で各マーク位置を測定し、それらのマーク位置に対しても同じ変換を行うことで、被検面Ｓ１、Ｓ２上にある各マークｖの相対的な位置を算出することが可能となる。
【００５５】
この解析により得られた座標変換を、各被検面Ｓ１、Ｓ２のローカル座標系Ａ１、Ａ２にも実行することで、図１０に示すような、複数の面Ｓ１、Ｓ２におけるローカル座標系Ａ１、Ａ２の相対的な位置関係を明確にすることが可能となる。なお、図１０では、エッジＥを構成する２面のみの例を示したが、これに限定するものではなく、３面以上のローカル座標系の相対位置も同様の手法により求めることが可能となる。また、本実施例では、１つの被検面に対して基準ブロックＤの１つの基準面を同時に測定したが、被検物の形状によっては２つ以上の被検物に対して１つの基準面を同時に測定するようにしてもよい。これらの手法により、複数の面における相対的な偏心量が分かるため、光学性能劣化の要因解明、修正等に反映させることが可能となる。
【００５６】
また、本手法の結果を基に製造を実施することで、精度の高い光学素子を作製することが可能となる。
【００５７】
図１１〜図１４を参照にして、枠Ｗに光学素子（例えばプリズム）が複数配置された被検物Ｏの、各光学素子の偏心量を、被検物Ｏを保持する枠Ｗに固定した基準となる素子（基準ブロック）Ｄを用いて算出する方法について説明する。このとき、被検物Ｏは、ある方向において、各光学素子を構成する少なくとも１面の面形状が測定できるようにする。図１１〜図１４では、プリズムＰ１とプリズムＰ２が枠Ｗ内に配置され、プリズムＰ１を構成する面Ｓ１−１とプリズムＰ２を構成するＳ２−２が外側に出ており、光プローブ２を照射することで各面の測定が可能となっている。
【００５８】
図１１は、プリズムＰ１の被検面Ｓ１−１と基準ブロックＤの１つの基準面Ｈに対して光プローブ２を走査することにより、被検面Ｓ１−１の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図、図１２は、被検面Ｓ１−１の上面図、図１３は、プリズムＰ２の被検面Ｓ２−１と基準ブロックＤの他の基準面Ｈに対して光プローブ２を走査することにより、被検面Ｓ２−１の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図、図１４は、被検面Ｓ２−１の上面図である。
【００５９】
被検物Ｏは基準ブロックＤと保持具Ｃで一体に固定して保持されており、基準ブロックＤの各基準面Ｈとそれに対応した各被検面Ｓ１−１、Ｓ２−１の形状をそれぞれ非接触３次元測定機を用いて同じ測定座標系で測定できるようにする。なお、各被検面Ｓ１−１、Ｓ２−１の面形状データは、それぞれ各被検面Ｓ１−１、Ｓ２−１の設計値に当てはめるフィッティングを行うことで、被検面Ｓ１−１、Ｓ２−１を表すローカル座標系Ａ１−１、Ａ２−１の位置を求めておく。
【００６０】
また、ローカル座標系算出の際には、各被検面の設計形状を座標変換して、面形状データと座標変換した各設計形状を重ね合わせた際に、残差が最小となるような座標変換パラメータを求める最適化の解析行ってもよい。
【００６１】
基準面Ｈの形状は、被検物ＯのプリズムＰ１、Ｐ２の各被検面Ｓ１−１、Ｓ２−１の測定と同時に、少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点の位置を測定できるように構成することが望ましい。このとき、測定に用いた少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点は、それらの測定結果より基準ブロックＤの各基準面Ｈの位置を定義できるようなものとする必要がある。さらに、少なくとも各測定面Ｈと同時に測定するエッジｅの角度や長さは、予め高精度に測定しておき、これらの既知のデータから測定値で定義される各基準面Ｈの相対的な位置が分かるようにしておく。
【００６２】
なお、基準ブロックＤの形状は、例えば、被検物のプリズムＰ１、Ｐ２の形状に合わせて各被検面Ｓ１−１、Ｓ２−１を平面で近似した面を有する多面体の形状であってもよい。このとき、各被検面Ｓ１−１、Ｓ２−１の設計値のローカル座標系Ａ１−１、Ａ２−１で定義される平面を有する多面体の形状であってもよい。基準ブロックＤを平面で構成する場合、測定が高精度かつ簡略化でき、解析も他の曲面に対して容易となる。また、材質としては、ガラスや金属等であってもよい。これらの材質で製作すると、高い面精度での加工が可能となるため、基準面の角度を高精度に測定することができる。また、鋭利なエッジ形状が形成できるため、基準面の高精度な測定が可能となる。
【００６３】
次に、測定方法について説明する。まず、図１１〜図１４で示すように、各被検面Ｓ１−１、Ｓ２−１毎に基準ブロックＤのエッジｅの形状と、被検物ＯであるプリズムＰ１、Ｐ２の各被検面Ｓ１−１とＳ２−１の有効エリアＢ１−１とＢ２−１内の面形状を、同じ非接触３次元測定機を用いて同じ測定座標系で測定する。このとき、例えば、測定機の関係で、光プローブ２の入射する方向に対して被検面Ｓ１−１、Ｓ２−１が略垂直になるように、被検面Ｓ１−１、Ｓ２−１を上に向ける必要がある場合、図１１〜図１４に示すように、各面の測定毎に被検物Ｏを回転して保持する必要がある。そのため、図示しない回転機構を用いて、被検物Ｏと基準ブロックＤを所望の方向に回転させて固定することになる。このとき、被検物Ｏと基準ブロックＤは、回転によっても相対的な位置関係が変化しないようにする。
【００６４】
このとき、基準ブロックＤを、各被検面Ｓ１−１、Ｓ２−１の設計値のローカル座標系Ａ１−１、Ａ２−１で定義される平面を有する多面体の形状にしておくと、被検物Ｏの各被検面Ｓ１−１、Ｓ２−１と基準ブロックＤの基準面の測定の際に、被検物Ｏの各被検面Ｓ１−１、Ｓ２−１と基準ブロックＤの基準面が、同時に光プローブ２の入射する方向に対して略垂直になるように配置することが可能となるため、測定を容易に実行することができる。
【００６５】
基準ブロックＤは、例えば各基準面の辺の長さといった既知の測定値に対応させることで、基準ブロックＤの測定値より基準面位置を求めることができるような項目の測定を行う。図１１〜図１４では、各基準面Ｈ毎に２つのエッジを測定した例を示している。これらの測定データから、基準ブロックＤの基準面Ｈの位置を求めることが可能となる。
【００６６】
なお、基準面Ｈの位置の導出には、図９で示した例と同様の手法を用いることができる。これにより、基準ブロックＤの各基準面Ｈの位置を求めることが可能となる。さらに、同じ測定座標系で被検面Ｓ１−１、Ｓ２−１の形状を測定することにより、基準面Ｈと被検面Ｓ１−１、Ｓ２−１の相対的な位置を各被検面Ｓ１−１、Ｓ２−１毎に把握することが可能となる。
【００６７】
さらに、基準ブロックＤを構成する基準面Ｈの既知のデータに対応させて、各基準面Ｈの測定値により求められた各面の位置を変換し、各面の相対的な位置関係を合わせる。このとき、シフトや回転といった座標変換を行う必要がある。
【００６８】
なお、各面の相対的な位置を求めるのには、図９で示した例と同様の手法を用いることができる。これらの変換を各基準面と同じ測定座標系で測定した各被検面Ｓ１−１、Ｓ２−１に対しても行うことで、被検面Ｓ１−１、Ｓ２−１の相対的な位置を把握することが可能となる。
【００６９】
この解析により得られた座標変換を、各被検面Ｓ１−１、Ｓ２−１の各ローカル座標系Ａ１−１、Ａ２−１にも実施することで、図１５に示すような、異なる光学素子（プリズムＰ１、Ｐ２）を構成する複数の面Ｓ１−１、Ｓ２−１におけるローカル座標系Ａ１−１、Ａ２−１の相対的な位置関係を求めることが可能となる。
【００７０】
なお、図１１〜図１４では、２個のプリズムＰ１、Ｐ２から構成される例を示したが、これに限定されるものではなく、３個以上の光学素子の相対位置も同様の手法により求めることが可能となる。また、光学素子（プリズムＰ１、Ｐ２）について、被検面を１面とした例を示したが、これに限定されるものではなく、各素子について、複数の面を測定してもよく、これによりより多くの偏心及び寸法の情報を得ることが可能となる。この際には、基準ブロックの基準面の数を必要に応じて増やしてもよい。また、被検物として異なるプリズムの相対位置を求める例を示したが、被検物はこれに限定されるものではなく、レンズ、光学素子の金型、絞り、枠Ｗといったものでもよい。例えば、枠の場合、被検面の面形状を測定してもよいが、測定値から枠の位置が決定できるものを測定すればよく、例えば、凹凸、マークといったものと基準ブロックＤの基準面Ｈを同じ測定座標系で測定してもよい。
【００７１】
また、枠Ｗに組み込む前に、各プリズムの各面のローカル座標の相対位置を、例えば図９で示した手法により求めておけば、各プリズム毎にプリズムを構成する各面のローカル座標系の相対位置が既知であるため、それらの結果を図１５で示した各プリズムＰ１、Ｐ２の被検面Ｓ１−１、Ｓ２−１をローカル座標系Ａ１−１、Ａ２−１の位置に対応させることで、図１６に示すように、プリズムＰ１を構成するＳ１−１以外の面（Ｓ１−２、Ｓ１−３）及びプリズムＰ２を構成するＳ２−１以外の面（Ｓ２−２、Ｓ２−３）の各面のローカル座標系（Ａ１−２、Ａ１−３、Ａ２−２、Ａ２−３）の相対位置を求めることができる。これらの手法により、複数の素子における相対的な偏心量が分かるため、光学性能劣化の要因解明、修正等に反映させることが可能となる。また、本手法の結果を基に製造を実施することで、精度の高い光学系を作製することが可能となる。
【００７２】
次に、図１７を参照にして、例えば非球面レンズのような被検物Ｏに対して、表裏に配置された被検面のＳ３−１とＳ３−２の偏心量を、被検物Ｏに固定した基準となる素子（基準ブロック）Ｄを用いて算出する方法について説明する。図１７（ａ）は非球面レンズＯの被検面Ｓ３−１と基準ブロックＤの１つの基準面Ｈに対して光プローブ２を走査することにより、被検面のＳ３−１の形状、基準面Ｈのエッジｅの形状を測定する様子を示す横から見た図、図１７（ｂ）は被検面Ｓ３−１の斜視図、図１７（ｃ）は被検面Ｓ３−２と基準ブロックＤの他の基準面Ｈに対して光プローブ２を走査することにより、被検面のＳ３−２の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図である。
【００７３】
被検物Ｏは基準ブロックＨと保持具Ｃで一体に固定して保持されており、基準ブロックＤの各基準面Ｈとそれに対応した各被検面Ｓ３−１、Ｓ３−２の形状をそれぞれ非接触３次元測定機を用いて同じ測定座標系で測定できるようにする。なお、各被検面Ｓ３−１、Ｓ３−２の面形状データは、それぞれ各被検面Ｓ３−１、Ｓ３−２の設計値に当てはめるフィッティングを行うことで、被検面Ｓ３−１、Ｓ３−２を表すローカル座標系Ａ１−１、Ａ２−１の位置を求めておく。
【００７４】
基準ブロックＨの形状は、被検物Ｏの非球面レンズの各被検面Ｓ３−１、Ｓ３−２の測定と同時に少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点の位置を測定できるように構成することが望ましい。このとき、測定に用いた少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点は、それらの測定結果より基準ブロックＤの各基準面にＨの位置を定義できるようなものとする必要がある。さらに、少なくとも各測定面Ｈと同時に測定するエッジｅの角度や長さは、予め高精度に測定しておき、これらの既知のデータから測定値で定義される各基準面Ｈの相対的な位置が分かるようにしておく。
【００７５】
なお、基準ブロックＤの形状は、例えば、被検物Ｏの各被検面Ｓ３−１、Ｓ３−２の厚さ程度の直方体であってもよい。このとき、対向する平面を基準面として、各基準面で２つのエッジを測定してもよい。このとき、基準ブロックＤの各辺の長さ、各基準面間の平行度や基準面に隣合う面との角度（直交度）、基準面間の高さ等を高精度に測定しておくことが望ましい。
【００７６】
次に、測定方法について説明する。まず、図１７に示すように、各被検面Ｓ３−１、Ｓ３−２毎に基準ブロックＤのエッジｅの形状と、被検物Ｏの各被検面Ｓ３−１、Ｓ３−２の有効エリアの面形状を、非接触３次元測定機を用いて同じ測定座標系で測定する。このとき、例えば測定機の関係で、光プローブ２の入射する方向に対して被検面が略垂直になるように、被検面Ｓ３−１、Ｓ３−２を上に向ける必要がある場合、図１７（ａ）〜（ｃ）に示すように、各面の測定毎に被検物Ｏを略１８０°回転して保持する必要がある。このとき、被検物Ｏと基準ブロックＤは、回転によっても相対的な位置関係が変化しないようにする。
【００７７】
基準ブロックＤは、例えば各基準面の辺の長さといった既知の測定値に対応させることで、基準ブロックＤの測定値より基準面位置を求めることができるような項目の測定を行う。図１７では、各基準面Ｈ毎に２つのエッジを測定した例を示している。これらの測定データから、基準ブロックＤの基準面Ｈの位置を求めることが可能となる。なお、基準面Ｈの位置の導出には、図９で示した例と同様の手法を用いることができる。これにより、基準ブロックＤの各基準面Ｈの位置を求めることが可能となる。さらに、同じ測定座標系で被検面Ｓ３−１、Ｓ３−２の形状を測定することにより、基準面Ｈと被検面Ｓ３−１、Ｓ３−２の相対的な位置を各被検面Ｓ３−１、Ｓ３−２毎に把握することが可能となる。
【００７８】
さらに、基準ブロックＤを構成する基準面Ｈの既知のデータに対応させて、各基準面Ｈの測定値により求められた各面の位置を変換し、各面の相対的な位置関係を合わせる。基準ブロックＤが略直方体の場合、例えば、測定により算出した各基準面の頂点の座標と各基準面の傾きを、既知のデータの頂点の相対位置と平行度のデータと対応させてもよい。なお、図１７では、基準面の境界となる稜線のエッジの形状は測定していないが、各基準面のエッジの相対的な位置関係が既知であれば、解析は可能となる。これらの変換を各基準面と同じ測定座標系で測定した各被検面Ｓ３−１、Ｓ３−２に対しても行うことで、被検面Ｓ３−１、Ｓ３−２の相対的な位置を把握することが可能となる。また、対向する基準面に加えて、両基準面とそれぞれ接する基準面の相対位置を測定し、それらの結果を、既知である基準ブロックの各面の角度に対応させて、対向する基準面の相対位置を導出する解析を行ってもよい。
【００７９】
この解析により得られた座標変換を、各被検面Ｓ３−１、Ｓ３−２の各ローカル座標系Ａ３−１、Ａ３−２にも実施することで、図１７（ｄ）に示すように、非球面レンズを構成する面Ｓ３−１、Ｓ３−２におけるローカル座標系Ａ３−１、Ａ３−２の相対的な位置関係を明確にすることが可能となる。また、解析により各被検面の相対位置が分かるので、偏心の他に、レンズの肉厚等の情報も得ることが可能となる。さらに、これらの情報を基に製造を実施することで精度の高い光学素子を作製することが可能となる。
【００８０】
被検面の形状が非球面の場合、被検面の面形状データから設計値に当てはめるフィッティングを行うことでローカル座標の位置を求めることができるが、被検面の形状が球面の場合は、同手法を用いてもローカル座標系の位置を決定することができない。そのような場合は、被検面上に、被検面の形状の測定時に同時に測定することで、ローカル座標系の位置を求めることが可能となるようなマークＭを付けておいてもよい。この場合、ローカル座標系に対するマークＭの相対位置は既知としておくことで、複数のマークの測定結果から、ローカル座標系の位置の導出が可能となる。なお、マークの形状は、上記解析が可能であれば形状を限定するものではなく、例えば、図１８（ａ）に示すような十字や、図１８（ｂ）に示す円柱であってもよい。また、外形から上記解析が可能であれば、マーク等を加工する必要はない。例えば、図１８（ｃ）に示すような、小判型の外形をしている場合、外形の直線部の形状や、円弧部との頂点の位置等からローカル座標系の相対位置が導出できれば、それらの測定結果から被検面のローカル座標系を導出する解析を行ってもよい。
【００８１】
また、被検面の形状が球面の場合、例えば、面形状データを球でフィッティングすることで球心位置を算出することは可能なので、各面の相対的な球心位置を求めることも可能である。その際に、球面の被検面の測定において、例えば図１８に示すようなマークや外形といったものを同じ座標系で測定しておくことが望ましい。
【００８２】
なお、外形の測定では、図１８（ｃ）に示すような小判型に限定するものではなく、通常の円形の外形であってもよい。その場合は、外形の測定結果を円でフィッティングすることにより、外形中心の位置を求めることが可能となる。それによって、例えば、マークの位置や外形中心といった基準位置に対する各面の球心の相対位置を求めることが可能となる。また、同様に非球面を含んだ場合にも、例えば、非球面の面形状データを球面でフィッティングすることで、ローカル座標系の他に、近似球心位置を求めることも可能である。このように本手法を用いることで、回転対称な光学面を有する被検物に対して、偏心の測定を行うことが可能となる。
【００８３】
次に、図２０を参照にして、図１９に示すような枠Ｗに光学素子（例えば、レンズ、プリズム）が複数配置された被検物Ｏの各光学素子の偏心量を、被検物Ｏの枠Ｗに固定した基準となる素子（基準ブロック）Ｄを用いて算出する方法について説明する。このとき、被検物Ｏは、プリズムによって光軸が折り曲げられた光学系となっている。なお、被検物Ｏは、ある方向において複数の面の面形状が測定できるようにする。そのため、枠Ｗは、被検面測定の際に、枠Ｗと測定機を構成する部材、例えば図示しない光プローブ２を照射するレンズが衝突しないような構成とすることが望ましい。
【００８４】
図１９では、第１のレンズ群Ｇ１とプリズムＰ３と第２のレンズ群Ｇ２が枠Ｗ内に配置され、第１のレンズ群Ｇ１のレンズＬ１−１を形成する面ＳＬ１−１とプリズムＰ３を形成する面ＳＰ３−２と、第２のレンズ群Ｇ２のレンズＬ２−５を形成する面ＳＬ２−５が外側に出ており、光プローブ２を照射することで各面の測定が可能となっている。
【００８５】
図２０（ａ）は、被検面ＳＬ１−１と基準ブロックＤの１つの基準面Ｈに対して光プローブ２を走査することにより、被検面ＳＬ１−１の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図、図２０（ｂ）は、被検面ＳＰ３−２と基準ブロックＤの他の基準面Ｈに対して光プローブ２を走査することにより、被検面のＳＰ３−２の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図、図２０（ｃ）は、被検面ＳＬ２−５と基準ブロックＤの他の基準面Ｈに対して光プローブ２を走査することにより、被検面ＳＬ２−５の形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図である。
【００８６】
被検物Ｏは基準ブロックＨと保持具Ｃで一体に固定して保持されており、基準ブロックＤの各基準面Ｈとそれに対応した各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の形状をそれぞれ非接触３次元測定機を用いて同じ測定座標系で測定できるようにする。なお、各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の面形状データは、それぞれ各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の設計値に当てはめるフィッティングを行うことで、被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５を表すローカル座標系ＡＬ１−１−１、ＡＰ３−２、ＡＬ２−５−２の位置を求めておく。
【００８７】
また、ローカル座標系算出の際には、各被検面の設計形状を座標変換して、面形状データと座標変換した各設計形状を重ね合わせた際に、残差が最小となるような座標変換パラメータを求める最適化の解析行ってもよい。
【００８８】
基準ブロックＤの形状は、被検物ＯのレンズＬ１−１、Ｌ２−５、プリズムＰ３の各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の測定と同時に少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点の位置を測定できるように構成することが望ましい。このとき、測定に用いた少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点は、それらの測定結果より基準ブロックＤの各基準面にＨの位置を定義できるようなものとする必要がある。さらに、少なくとも各測定面Ｈと同時に測定するエッジｅの角度や長さは、予め高精度に測定しておき、これらの既知のデータから測定値で定義される各基準面Ｈの相対的な位置が分かるようにしておく。
【００８９】
なお、基準ブロックＤの形状は、例えば、被検物Ｏの形状に合わせて各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５を平面で近似した面を有する多面体の形状であってもよい。このとき、各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の設計値のローカル座標系ＡＬ１−１−１、ＡＰ３−２、ＡＬ２−５−２で定義される平面を有する多面体の形状であってもよい。
【００９０】
次に、測定方法について説明する。まず、図２０で示すように、各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５毎に基準ブロックＤのエッジｅの形状と、被検物Ｏの各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の有効エリア内の面形状とを、非接触３次元測定機を用いて同じ測定座標系で測定する。このとき、例えば測定機の関係で、光プローブ２の入射する方向に対して被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５が略垂直になるように、被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５を上に向ける必要がある場合、図２０（ａ）〜（ｃ）に示すように、各面の測定毎に被検物Ｏを回転して保持する必要がある。そのため、図示しない回転機構を用いて、被検物Ｏと基準ブロックＤを所望の方向に回転させて固定することになる。このとき、被検物Ｏと基準ブロックＤは、回転によっても相対的な位置関係が変化しないようにする。
【００９１】
基準ブロックＤは、例えば各基準面の辺の長さといった既知の測定値に対応させることで基準ブロックＤの測定値より基準面位置を求めることができるような項目の測定を行う。図２０では、各基準面Ｈ毎に２つのエッジを測定した例を示している。これらの測定データから、基準ブロックＤの基準面Ｈの位置を求めることが可能となる。なお、基準面Ｈの位置の導出には、図９で示した例と同様の手法を用いることができる。これにより、基準ブロックＤの各基準面Ｈの位置を求めることが可能となる。さらに、同じ測定座標系で被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の形状を測定することにより、基準面Ｈと被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の相対的な位置を各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５毎に把握することが可能となる。
【００９２】
さらに、基準ブロックＤを構成する基準面Ｈの既知のデータに対応させて、各基準面Ｈの測定値により求められた各面の位置を変換し、各面の相対的な位置関係を合わせる。このとき、シフトや回転といった座標変換を行う必要がある。なお、各面の相対的な位置を求めるのには、図９で示した例と同様の手法を用いることができる。これらの変換を各基準面と同じ測定座標系で測定した各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５に対しても行うことで、被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の相対的な位置を把握することが可能となる。
【００９３】
この解析により得られた座標変換を、各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５の各ローカル座標系ＡＬ１−１−１、ＡＰ３−２、ＡＬ２−５−２にも実施することで、図２２に示すような、複数の面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５におけるローカル座標系ＡＬ１−１−１、ＡＰ３−２、ＡＬ２−５−２の相対的な位置関係を求めることが可能となる。
【００９４】
また、枠Ｗに組み込む前に、被検物内に配置された各光学素子の各面のローカル座標の相対位置を、例えば各群やプリズム毎に求めておくことが望ましい。図２１（ａ）〜（ｃ）は、被検物を構成するレンズ群Ｇ１（レンズＬ１−１、Ｌ１−２から構成）とプリズムＰ３とレンズ群Ｇ２（レンズＬ２−１、Ｌ２−２、Ｌ２−３、Ｌ２−４、Ｌ２−５から構成）毎に、各面の偏心を測定した結果を示している。レンズ群Ｇ１、Ｇ２内における偏心は既存の測定機を用いて導出することが可能であり、また、プリズムＰ３に関しても、例えば図９で示した手法により偏心を導出することは可能である。導出された結果から、各面毎のローカル座標系の相対位置が分かることになり、図２１（ａ）〜（ｃ）に示すように、例えば、レンズ群Ｇ１では、レンズＬ１−１を構成する面のローカル座標系ＡＬ１−１−１、ＡＬ１−１−２と、レンズＬ１−２を構成する面のローカル座標系ＡＬ１−２−１、ＡＬ１−２−２の相対位置が分かる。また、例えば、プリズムＰ３では、プリズムＰ３を構成する面のローカル座標系ＡＰ３−１、ＡＰ３−２、ＡＰ３−３の相対位置が分かる。また、レンズ群Ｇ２では、レンズＬ２−１を構成する面のローカル座標系ＡＬ２−１−１、ＡＬ２−１−２と、レンズＬ２−２を構成する面のローカル座標系ＡＬ２−２−１、ＡＬ２−２−２と、レンズＬ２−３を構成する面のローカル座標系ＡＬ２−３−２と、レンズＬ２−４を構成する面のローカル座標系ＡＬ２−４−１、ＡＬ２−４−２と、レンズＬ２−５を構成する面のローカル座標系ＡＬ２−５−１、ＡＬ２−５−２の相対位置が分かる。
【００９５】
このとき、各面のローカル座標系の相対位置がレンズ群やプリズム毎に既知であるため、図２０に示すように、レンズＬ１−１、Ｌ２−５、プリズムＰ３の各被検面ＳＬ１−１、ＳＰ３−２、ＳＬ２−５のローカル座標系ＡＬ１−１−１、ＡＰ３−２、ＡＬ２−５−２との相対を組み合わせることで、レンズ群Ｇ１を構成する被検面ＳＬ１−１以外の面及びプリズムＰ３を構成するＳＰ３−２以外の面及びレンズ群Ｇ２を構成するＳＬ２−５以外の面を含む各ローカル座標系（ＡＬ１−１−１、ＡＬ１−１−２、ＡＬ１−２−１、ＡＬ１−２−２、ＡＰ３−１、ＡＰ３−２、ＡＰ３−３、ＡＬ２−１−１、ＡＬ２−１−２、ＡＬ２−２−１、ＡＬ２−２−２、ＡＬ２−３−２、ＡＬ２−４−１、ＡＬ２−４−２、ＡＬ２−５−１、ＡＬ２−５−２）の相対位置を求めることができる。これらの手法により、複数の素子における相対的な偏心量が分かるため、光学性能劣化の要因解明、修正等に反映させることが可能となる。また、本手法の結果を基に製造を実施することで、精度の高い光学系を作製することが可能となる。
【００９６】
なお、各被検面の形状を測定する際、被検面が略上を向くように配置させる必要がある場合には、図示しない回転機構を用いると示したが、測定時に基準ブロックＤと被検物の相対位置が変化しないで固定できればよいので、このような保持が可能であれば回転機構を用いなくてもよく、例えば、配置する姿勢を変えて固定してもよい。
【００９７】
ところで、図１や図２のような非接触３次元測定機の光プローブ２を走査して被検物Ｏの被検面１（Ｓ１、Ｓ２）の３次元面形状を測定するには、被検面１の全面を連続的に隈なく走査することは測定時間等の関係で困難であるので、通常は、測定面内のサンプリングされた飛び飛びの点で測定するのが実際である。その飛び飛びの点間の光プローブ２の移動に関しては、従来は、図２４（ｂ）に示すように、特定の位置で高さを測定した▲１▼の状態の光プローブ２をそのままの高さを保ったまま水平に移動して▲２▼の状態で次の位置の測定を行う。しかしながら、このような測定点間の光プローブ２の移動では、被検面１の勾配が急である場合には、光プローブ２を出す対物レンズ１５、２４が被検面１と接触して被検面１あるいは対物レンズ１５、２４を傷つけたり、被検面１との距離が遠くなりすぎ反射した光が再び対物レンズ１５、２４に取り込めずに測定ができなくなる場合があり得る。
【００９８】
そこで、本発明の測定方法においては、図２４（ａ）に示すように、特定の位置で高さを測定した▲１▼の状態の光プローブ２を所定の微小距離αだけ上方へ移動させて▲２▼の状態にし、その後、被検面１の設計形状から微小距離αだけ離れてその形状に沿うように移動させて次の測定位置に持ってきて▲３▼の状態にし、その状態で次の測定位置の高さの測定を行うようにする。ここで、▲２▼から▲３▼の状態への移動は、最短距離で移動させても、あるいは、設計値＋αの面に沿うように移動させてもよい。このような光プローブ２の移動方法をとることにより、対物レンズ１５、２４が被検面１と接触すること、及び、反射光が取り込めなくなることが何れも回避可能になる。なお、微小距離αは０以上で、被検面１からの反射光を非接触３次元測定機の対物レンズで取り込むことができる範囲において、任意に設定することができる。
【００９９】
次に、被検物Ｏの被検面上のローカル座標系で指定した座標位置に、マークｖを加工しておいたサンプルを使った測定方法について説明する。
【０１００】
図２５は、マークｖを加工しておいたサンプルの一例である。図２５に示すように、本発明の測定方法では、被検物Ｏの被検面上のローカル座標系で指定した座標位置にマークｖを加工しておいたサンプルを用いてもよい。この場合、マーク位置を、被検面の面形状測定時に同じ測定座標系で測定し、各マーク位置の測定値から、被検面のローカル座標系の位置を求めることができる。従って、ローカル座標系導出の際に、フィッティングや最適化等の解析が必要ないため、解析が容易となる。
【０１０１】
なお、マーク形状は、上記解析が可能であれば、形状や個数を限定するものではなく、例えば、形状は円柱、角柱、円錐、角錐、十字状、Ｌ字状、交線、点等でもよい。また、測定が高精度にできれば凸形状、凹形状のどちらであってもよい。また、マーク加工位置は、光学系の有効エリアＢ１、Ｂ２以外の領域に加工することが望ましい。マーク位置は、例えば、マーク形状が円柱の場合には、上面の外形の円の中心位置としてもよい。また、十字状の場合には、各直線の交点の位置としてもよい。
【０１０２】
なお、各マークは、被検面の面形状測定時に同じ測定座標系でマーク形状を測定できれば、必ずしも被検面と同一の面内にある必要はなく、例えば、被検物Ｏを構成する別の面にあってもよい。
【０１０３】
図２６は、マークｖを加工しておいたサンプルの別の一例である。図２６に示すように、発明の測定方法では、被検物Ｏの被検面上にローカル座標系で指定した座標位置にマークｖを加工しておいたサンプルを用いてもよい。この場合、マーク位置を、被検面の面形状測定時に同じ測定座標系で測定し、各マーク位置の測定値から、被検面のローカル座標系の位置を求めることができる。よって、被検面Ｓ１、Ｓ２上の各マークｖの測定結果より、各被検面を示すローカル座標系Ａ１，Ａ２の位置を求めておく。
【０１０４】
また、基準ブロックの形状は、図２７に示すように、底面が多面体からなる角柱であってもよい。この場合、被検物Ｏを保持する際に、各被検面Ｓ１、Ｓ２と、それぞれ基準ブロックＤを構成する少なくとも１つの面が略水平となるように保持する。ここで、各被検面Ｓ１、Ｓ２と、それぞれ略水平になった基準ブロックＤの面を基準面Ｈとする。
【０１０５】
図２７では、基準ブロックを構成する面Ｈ１、Ｈ２が、それぞれ各被検面Ｓ１、Ｓ２と略水平に保持されているため、各被検面の基準面Ｈとして使用する。このような構成にすることにより、被検物Ｏの形状にあわせて基準ブロックを製作する必要がなく、汎用的に同一の基準ブロックを使用することができる。なお、図２７では、基準ブロックの形状を、８角柱としたが、上記保持が可能であれば、これに限定するものではない。
【０１０６】
次に、図２８〜図３１を参照にして、枠Ｗに光学素子（ 例えばプリズム） が複数配置された被検物Ｏの、各光学素子の偏心量を、被検物Ｏを保持する枠Ｗに固定した基準となる素子（ 基準ブロック） Ｄを用いて算出する第２の方法について説明する。このとき、被検物Ｏは、ある方向において、各光学素子を構成する少なくとも１面に加工しておいたマーク位置を測定できるようにする。
【０１０７】
なお、マーク形状は、上記測定が可能であれば、形状や個数を限定するものではなく、例えば、形状は円柱、角柱、円錐、角錐、十字状、Ｌ字状、交線、点等がある。また、測定が高精度にできれば凸形状、凹形状のどちらであってもよい。また、マーク加工位置は光学系の有効エリアＢ１−１、Ｂ２−１以外の領域に加工することが望ましい。
【０１０８】
図２８〜図３１では、プリズムＰ１とプリズムＰ２が枠Ｗ内に配置され、プリズムＰ１を構成する面Ｓ１−１とプリズムＰ２を構成する面Ｓ２−１上にそれぞれ加工されたマークｖが外側に出ており、光プローブを照射することで各マーク形状の測定が可能となっており、その結果マークｖの位置を求めることが可能である。
【０１０９】
図２８は、プリズムＰ１の被検面Ｓ１−１と基準ブロックＤの１つの基準面Ｈに対して光プローブを走査することにより、被検面のＳ１−１上にあるマーク形状、基準面Ｈのエッジｅ の形状を測定する様子を示す斜視図、図２９は被検面Ｓ１−１の上面図、図３０はプリズムＰ２の被検面Ｓ２−１と基準ブロックＤの他の基準面Ｈに対して光プローブを走査することにより、被検面のＳ２−１上にあるマーク形状、基準面Ｈのエッジｅの形状を測定する様子を示す斜視図、図３１は被検面Ｓ２−１の上面図である。
【０１１０】
被検物Ｏは基準ブロックＨと保持具Ｃで一体に固定して保持されており、基準ブロックＤの各基準面Ｈとそれに対応した各被検面Ｓ１−１、Ｓ２−１上にあるマーク形状をそれぞれ非接触３次元測定機を用いて同じ測定座標系で測定できるようにして、マーク形状の測定値よりマーク位置を求める。
【０１１１】
基準ブロックの形状は、被検物ＯのプリズムＰ１、Ｐ２の各被検面Ｓ１−１、Ｓ２−１の測定と同時に少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点の位置を測定できるように構成することが望ましい。このとき、測定に用いた少なくとも２つのエッジｅ若しくは１つのエッジｅと座標が既知である点により、基準ブロックＤの各基準面にＨの位置を定義できるようなものとする必要がある。さらに少なくとも各測定面Ｈと同時に測定するエッジｅの角度や長さは、予め高精度に測定しておき、これらの既知のデータから測定値で定義される各基準面Ｈの相対的な位置が分かるようにしておく。
【０１１２】
次に測定方法について説明する。図１１〜図１４で示した例と同様の手法により、各被検面Ｓ１−１、Ｓ２−１毎に基準ブロックＤのエッジｅの形状と、被検物ＯであるプリズムＰ１、Ｐ２の各被検面Ｓ１−１、Ｓ２−１上にある各マークｖを、同じ非接触３次元測定機を用いて同じ測定座標系で測定する。このとき、例えば測定機の関係で、光プローブの入射する方向に対して被検面を略垂直になるように、被検面Ｓ１−１、Ｓ２−１を上に向ける必要がある場合、図２８〜図３１に示すように、各面の測定毎に被検物Ｏを回転して保持する必要がある。そのため、図示しない回転機構を用いて、被検物Ｏと基準ブロックＤを所望の方向に回転させて固定することになる。このとき、被検物Ｏと基準ブロックＤは、回転によっても相対的な位置関係が変化しないようにする。
【０１１３】
なお、基準面Ｈの位置の導出には、図９で示した例と同様の手法を用いることができ、これにより、基準ブロックＤの各基準面Ｈの位置を求めることが可能となる。さらに、同じ測定座標系で被検面Ｓ１−１、Ｓ２−１上にある各マークｖの位置を測定することにより、被検面Ｈと被検面Ｓ１−１、Ｓ２−１上にあるマークｖの相対的な位置を各被検面Ｓ１−１、Ｓ２−１毎に把握することが可能となる。
【０１１４】
このマークｖについては、例えば図２６で示した同様の手法を用いることで、すなわち、各面の形状測定とともに、同じ測定座標系を用いてマーク位置を測定し、同様の解析をすることで、各面の面形状とともに、マークの相対位置を算出することが可能となる。したがって、被検面の面形状とマーク位置の相対位置を導出することが可能である。
【０１１５】
さらに、基準ブロックＤを構成する基準面Ｈの既知のデータに対応させて、各基準面Ｈの測定値により求められた各面の位置を変換し、各面の相対的な位置関係を合わせる。このとき、シフトや回転といった座標変換を行う必要がある。
【０１１６】
この解析により得られた座標変換を、各被検面Ｓ１−１、Ｓ２−１上にある各マークｖにも実施することで、各被検面Ｓ１−１、Ｓ２−１上にあるマークの相対的な位置を把握することが可能となる。
【０１１７】
また、枠Ｗに組み込む前に、各プリズムの各被検面のマーク位置とローカル座標系の相対位置を、例えば図２６で示した手法により求めておけば、各プリズム毎にプリズムを構成する各面のマークとローカル座標系の相対位置が既知となる。
【０１１８】
なお、マークが、被検面上のローカル座標系で指定した座標位置に加工してあれば、各マーク位置の測定結果より、容易にローカル座標系の位置を算出することが可能となる。そこで、例えば図２６で示した手法により、各プリズム毎にプリズムを構成する各面の複数のマークｖとローカル座標系の相対位置が分かる。
【０１１９】
ただし、各マークの、被検面のローカル座標系における座標位置が分からない場合でも、解析は可能である。この場合、マークの位置を測定する際に、同じ測定座標系を用いて、被検面の形状を測定するようにする。面形状データは、例えば座標変換によって、それぞれ各設計値形状に重ね合わせた際の残差が最小となるような最適化の解析を行うことで、被検面を表すローカル座標系の位置を求めることが可能となるので、各面毎にローカル座標系とマークｖの相対的な位置が分かる。そこで、例えば図２６で示した手法により、各プリズム毎にプリズムを構成する各面の面形状とローカル座標系とともに、各マークｖの相対位置が分かる。この場合、マークｖは、被検面と同一の面上になくても、同一の測定座標系で、マーク位置を測定できれば、同様の解析は可能である。
【０１２０】
そこで、これらの結果を図３０で示した各プリズムＰ１、Ｐ２の被検面Ｓ１−１、Ｓ２−１上にある同一の各マークの位置に対応させることで、図３１に示すように、プリズムＰ１を構成するＳ１−１以外の面（Ｓ１−２、Ｓ１−３）及びプリズムＰ２を構成するＳ２−１以外の面（Ｓ２−２、Ｓ２−３）の各面のローカル座標系（Ａ１−２、Ａ１−３、Ａ２−２、Ａ２−３）の相対位置も求めることができる。
【０１２１】
上記解析には、例えば対応する各被検面毎に、図３０で測定したマーク位置と、枠Ｗ組み込み前に測定した各プリズムでの対応する各マークを座標変換して、各マーク位置間の距離の総和が最小になるように座標変換パラメータを算出するような最適化の解析を行ってもよい。さらに、この解析によって導出した座標変換を、マーク位置と相対的な位置関係が既知である、被検面のローカル座標系や他の被検面のローカル座標系にも実施すればよい。
【０１２２】
これらの手法により、複数の素子における相対的な偏心量が分かるため、光学性能劣化の要因解明、修正等に反映させることが可能となる。また、本手法の結果を基に製造を実施することで精度の高い光学系を作製することが可能となる。
【０１２３】
なお、本手法では、枠Ｗに組み込み前後で被検面のマークの測定を行う必要があるが、マーク位置を算出する際にフィッティングや最適化等の解析を必要としないため、枠Ｗに組み込み前後での測定誤差の影響を少なくすることが可能となる。
【０１２４】
また、上記解析では、各プリズム毎に、マーク付の被検面を１面ずつ用いた場合を示したが、これに限定するものではなく、例えば１つのプリズムについて、複数の被検面上にあるマークを用いて解析を行ってもよい。この場合、マーク位置の対応の情報が増加する為、算出される複数の素子における相対的な偏心量の精度が向上する。
【０１２５】
以上の本発明の３次元座標測定方法は、例えば次のように構成することができる。
【０１２６】
〔１〕 被検物上のエッジ近傍にそのエッジに略沿う曲線を設定し、その曲線と略直交する方向に走査して、エッジに基づいて定められた位置の座標値を検出することを特徴とする３次元座標測定方法。
【０１２７】
〔２〕 前記曲線を多項式で定義することを特徴とする上記１記載の３次元座標測定方法。
【０１２８】
〔３〕 前記曲線が、エッジ近傍の複数の点を選択し、その複数の点をなだらかに結んで定義した曲線であることを特徴とする上記１記載の３次元座標測定方法。
【０１２９】
〔４〕 前記複数の点をなだらかに結ぶ際にスプライン演算を用いることを特徴とする上記３記載の３次元座標測定方法。
【０１３０】
〔５〕 被検物を構成する面の中、少なくとも１面が自由曲面からなることを特徴とする上記１記載の３次元座標測定方法。
【０１３１】
〔６〕 被検物が、構成面の中少なくとも１面が自由曲面からなる光学素子であることを特徴とする上記５記載の３次元座標測定方法。
【０１３２】
〔７〕 被検物が、構成面の中少なくとも１面が自由曲面からなる光学素子を製作するための金型であることを特徴とする上記５記載の３次元座標測定方法。
【０１３３】
〔８〕 複数の面から構成される被検物に対して、各面毎に３次元面形状とエッジ形状とをそれぞれ測定し、共通のエッジの測定値を対応させることにより前記複数の面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１３４】
〔９〕 異なる面毎に測定した共通のエッジの測定値が略同一の曲線上に乗るように対応付けをすることで、前記複数の面の相対的な位置関係を求めることを特徴とする上記８記載の３次元座標測定方法。
【０１３５】
〔１０〕 各面毎に測定した面形状測定値と面の設計値とを当てはめることで各面毎のローカル座標系を求め、１つの面で測定した共通のエッジの測定値と他の面で測定した共通のエッジの測定値とを対応させる座標変換を前記ローカル座標系にも行うことで、複数の面におけるローカル座標系の相対的な位置関係を求めることを特徴とする上記９記載の３次元座標測定方法。
【０１３６】
〔１０−１〕 各面毎に測定した面形状測定値と、座標変換した各被検面の設計形状を重ね合わせた際に、残差が最小となるような座標変換パラメータを求める最適化によって、各面毎のローカル座標系を求め、１つの面で測定した共通のエッジの測定値と他の面で測定した共通のエッジの測定値とを対応させる座標変換を前記ローカル座標系にも行うことで、複数の面におけるローカル座標系の相対的な位置関係を求めることを特徴とする上記９記載の３次元座標測定方法。
【０１３７】
〔１１〕 被検物を構成する面の中、少なくとも１面が自由曲面からなることを特徴とする上記９記載の３次元座標測定方法。
【０１３８】
〔１２〕 被検物が、構成面の中少なくとも１面が自由曲面からなる光学素子であることを特徴とする上記１１記載の３次元座標測定方法。
【０１３９】
〔１３〕 被検物が、構成面の中少なくとも１面が自由曲面からなるを製作するための金型であることを特徴とする上記１１記載の３次元座標測定方法。
【０１４０】
〔１４〕 複数の面から構成される被検物と、基準面の相対的な位置関係が既知な基準素子とを相対的に固定し、被検物の各被検面の３次元面形状と基準素子の形状とを同じ測定座標系でそれぞれ測定し、基準素子のエッジ形状の測定値から求まる面形状データに対応させて基準素子の各基準面の座標を変換し、その同じ座標変換を各被検面の３次元面形状測定値にも行うことにより、被検物の複数の被検面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４１】
〔１４−１〕 複数の面から構成される被検物と、基準面の相対的な位置関係が既知な基準素子と被検物とを相対的に固定し、被検物の各被検面の３次元面形状と基準素子とを同じ測定座標系でそれぞれ測定し、基準素子の測定値から求まる面形状データに対応させて各基準素子の基準面の座標を変換し、その同じ座標変換を各被検面のマークの位置にも行うことにより、被検物の複数の被検面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４２】
〔１４−２〕 複数の面から構成される被検物において、基準面の相対的な位置関係が既知な基準素子と被検物とを相対的に固定し、被検物の各被検面上にあるマークの位置と基準素子とを同じ測定座標系でそれぞれ測定し、基準素子の測定値から求まる面形状データに対応させて各基準素子の基準面の座標を変換し、その同じ座標変換を各被検面のマークの位置にも行うことにより、被検物の複数の被検面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４３】
〔１４−３〕 複数の面から構成される被検物において、基準面の相対的な位置関係が既知な基準素子と被検物とを相対的に固定し、被検物の各被検面上にあるマークの位置と基準素子とを同じ測定座標系でそれぞれ測定し、基準素子のエッジ形状の測定値から求まる面形状データに対応させて各基準素子の基準面の座標を変換し、その同じ座標変換を各被検面のマークの位置にも行うことにより、被検物の複数の被検面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４４】
〔１５〕 複数の面から構成される素子を複数個用いて構成する被検物において、基準面の相対的な位置関係が既知な基準素子と被検物を相対的に固定し、被検物の各素子の少なくとも１面の３次元形状と基準素子とを同じ座標系でそれぞれ測定し、基準素子のエッジ形状の測定値から求まる面形状データに対応させて基準素子の各基準面の座標を変換し、その同じ座標変換を各被検面の３次元面形状測定値にも行うことにより、各素子を構成する少なくとも１面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４５】
〔１５−１〕 複数の面から構成される素子を複数個用いて構成する被検物において、基準面の相対的な位置関係が既知な基準素子と被検物を相対的に固定し、被検物の各素子の少なくとも１面の３次元形状とと基準素子とを同じ測定座標系でそれぞれ測定し、基準素子の測定値から求まる面形状データに対応させて各基準素子の基準面の座標を変換し、その同じ座標変換を各被検面の３次元形状測定値にも行うことにより、各素子を構成する少なくとも１つの面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４６】
〔１５−２〕 複数の面から構成される素子を複数個用いて構成する被検物において、基準面の相対的な位置関係が既知な基準素子と被検物を相対的に固定し、被検物の各素子のそれぞれ少なくとも１つの被検面上にあるマークの位置と基準素子とを同じ測定座標系でそれぞれ測定し、基準素子の測定値から求まる面形状データに対応させて各基準素子の基準面の座標を変換し、その同じ座標変換を各被検面のマークの位置にも行うことにより、各素子を構成するそれぞれ少なくとも１つの面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４７】
〔１５−３〕 複数の面から構成される素子を複数個用いて構成する被検物において、基準面の相対的な位置関係が既知な基準素子と被検物を相対的に固定し、被検物の各素子のそれぞれ少なくとも１つの被検面上にあるマークの位置と基準素子とを同じ測定座標系でそれぞれ測定し、基準素子のエッジ形状の測定値から求まる面形状データに対応させて各基準素子の基準面の座標を変換し、その同じ座標変換を各被検面のマークの位置にも行うことにより、各素子を構成するそれぞれ少なくとも１つの面の相対的な位置関係を求めることを特徴とする３次元座標測定方法。
【０１４８】
〔１６〕 基準素子の少なくとも２つのエッジ、若しくは、１つのエッジと座標が既知である点の位置とを測定することにより基準素子の形状を求めることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１４９】
〔１７〕 基準素子を構成する各基準面のなす角度が既知であることを特徴とする上記１６記載の３次元座標測定方法。
【０１５０】
〔１８〕 基準面の測定するエッジは、各基準面からなる稜線を含むことを特徴とする上記１７記載の３次元座標測定方法。
【０１５１】
〔１９〕 基準面の少なくとも２つのエッジ、若しくは、１つのエッジと座標が既知である点の測定結果から、各基準面からなる稜線の位置と基準面を表す平面の位置を導出することを特徴とする上記１８記載の３次元座標測定方法。
【０１５２】
〔２０〕 同一の稜線を含む各基準面の測定結果からそれぞれ導出した稜線の位置が空間的に一致するように座標の変換を行い、これにより空間的に一致した稜線を回転軸として、稜線を含む各平面を、基準素子の既知の値と対応するように、座標の変換を行うパラメータを算出することを特徴とする上記１９記載の３次元座標測定方法。
【０１５３】
〔２１〕 前記座標の変換を、各基準面と同じ測定座標系で測定した各被検面の測定結果に対して実施することを特徴とする上記２０記載の３次元座標測定方法。
【０１５４】
〔２２〕 前記座標の変換を、各基準面と同じ測定座標系で測定した各被検面の測定結果から求めたローカル座標系に対して実施することを特徴とする上記２０記載の３次元座標測定方法。
【０１５５】
〔２３〕 各面毎に測定した面形状測定値と面の設計値とを当てはめることで各面毎のローカル座標系を求め、求めたローカル座標系に対して、各被検面の３次元面形状測定値に対して行う座標変換を行うことで、被検物の複数の被検面におけるローカル座標系の相対的な位置関係を求めることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１５６】
〔２３−１〕 各面被検面上のローカル座標系で指定した座標位置にマークを加工しておいたサンプルを用いて、各面毎に測定したマーク位置から、ローカル座標系を求め、求めたローカル座標系に対して、各基準面に対して行う座標変換を行うことで、被検物の複数の被検面におけるローカル座標系の相対的な位置関係を求めることを特徴とする上記１４又は１４−２又は１５又は１５−２記載の３次元座標測定方法。
【０１５７】
〔２３−２〕 各面毎に測定した面形状測定値と、座標変換した各被検面の設計形状を重ね合わせた際に、残差が最小となるような座標変換パラメータを求める最適化によって、各面毎のローカル座標系を求め、求めたローカル座標系に対して、各基準面に対して行う座標変換を行うことで、被検物の複数の被検面におけるローカル座標系の相対的な位置関係を求めることを特徴とする上記１４又は１４−２又は１５又は１５−２記載の３次元座標測定方法。
【０１５８】
〔２４〕 被検物を構成する面の中、少なくとも１面が自由曲面からなることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１５９】
〔２５〕 被検物が、構成面の中少なくとも１面が自由曲面からなる光学素子であることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１６０】
〔２６〕 被検物が、構成面の中少なくとも１面が自由曲面からなるを製作するための金型であることを特徴とする上記２４記載の３次元座標測定方法。
【０１６１】
〔２７〕 基準素子を構成する基準面が平面により構成されていることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。。
【０１６２】
〔２７−１〕 基準素子は、底面が多角形からなる角柱であることを特徴とする上記１４又は１４−３又は１５又は１５−２記載の３次元座標測定方法。
【０１６３】
〔２８〕 基準素子の形状は、被検面を平面で近似した構成の多面体であることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１６４】
〔２９〕 基準素子の形状は、被検面のローカル座標系で定義される平面で構成される多面体であることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１６５】
〔３０〕 基準素子はガラスでできていることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１６６】
〔３１〕 基準素子は金属でできていることを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１６７】
〔３２〕 被検物と基準素子は、回転機構を有する治具に保持することを特徴とする上記１４、１４−３、１５、１５−３のいずれかに記載の３次元座標測定方法。
【０１６８】
〔３３〕 非接触光プローブを用いて測定を行い、その際に特定の測定点から次の測定点へ非接触光プローブを移動させるのに、特定の測定点での非接触光プローブを所定の微小距離だけ被検面から離れる方向へ移動させ、次いで被検面の設計値からその微小距離だけ離れてその設計値に沿うように移動させて次の測定点へ移動させ、その状態で次の測定点の測定を行うことを特徴とする上記１から３２の何れか１項記載の３次元座標測定方法。
【０１６９】
〔３４〕 被検物を構成する各素子を構成する各面の相対的な位置関係が既知であることを特徴とする上記１５又は１５−３に記載の３次元座標測定方法。
【０１７０】
〔３５〕 複数の面から構成される素子を複数個用いて構成された被検物は、枠で保持されていることを特徴とする上記１６記載の３次元座標測定方法。
【０１７１】
〔３６〕 被検物を保持する枠は、被検面に光が照射できる構成にしたことを特徴とする上記１６記載の３次元座標測定方法。
【０１７２】
〔３７〕 被検物が回転対称な光学面を有することを特徴とする記１５又は１５−３に記載の３次元座標測定方法。
【０１７３】
〔３８〕 被検物が折り曲げられた光軸を有する特徴とする記１５又は１５−３に記載の３次元座標測定方法。
【０１７４】
〔３９〕 非接触光プローブで被検面の３次元座標を測定する３次元座標測定方法において、特定の測定点から次の測定点へ非接触光プローブを移動させる際に、特定の測定点での非接触光プローブを所定の微小距離だけ被検面から離れる方向へ移動させ、次いで被検面の設計値からその微小距離だけ離れてその設計値に沿うように移動させて次の測定点へ移動させ、その状態で次の測定点の測定を行うことを特徴とする３次元座標測定方法。
【０１７５】
〔４０〕 上記１から３９の何れか１項記載の３次元座標測定方法を用いた測定機。
【０１７６】
〔４１〕 上記１から３９の何れか１項記載の３次元座標測定方法で測定されたもの。
【０１７７】
【発明の効果】
以上の説明から明らかなように、本発明の３次元座標測定方法によると、外形に対する各被検面の設計座標系（ローカル座標系）の相対位置を正確に求めることができ、また、複数の被検面におけるローカル座標系の相対的な位置関係を明確にすることが可能となる。そのため、複数の被検面における相対的な偏心量が分かることになり、光学性能劣化の要因解明、修正等に反映させることが可能となる。
【図面の簡単な説明】
【図１】本発明において使用可能なオートフォーカスタイプの非接触３次元測定機の構成を概略的に示す図である。
【図２】本発明において使用可能な共焦点顕微鏡タイプの非接触３次元測定機の構成を概略的に示す図である。
【図３】円形状のエッジ部を測定する方法を説明するための図である。
【図４】本発明に基づいてエッジの形状を測定する方法を説明するための図である。
【図５】エッジの形状を測定する際の走査開始点を示す曲線の設定方法を説明するための図である。
【図６】本発明に基づいて外形に対する各面のローカル座標系の相対位置を求める方法を説明するための図である。
【図７】本発明に基づいて被検物の１つのエッジを共有する複数の被検面の偏心量を算出する方法を説明するための図である。
【図８】図７の方法で相対的な位置関係が明確になった複数の面のローカル座標系を示す図である。
【図９】本発明に基づいて被検物に固定した基準ブロックを用いて複数の被検面の偏心量を算出する方法を説明するための図である。
【図１０】図９の方法で相対的な位置関係が明確になった複数の面のローカル座標系を示す図である。
【図１１】本発明に基づいて被検物に固定した基準ブロックを用いて複数の素子の各素子を構成する被検面の偏心量を導出する方法を説明するための図中の、１つの素子の被検面と基準ブロックの１つの基準面に対して光プローブを走査することによりその被検面の形状、基準面のエッジの形状を測定する様子を示す斜視図である。
【図１２】図１１の被検面の上面図である。
【図１３】図１１の別の素子の被検面と基準ブロックの他の基準面に対して光プローブを走査することによりその被検面の形状、基準面のエッジの形状を測定する様子を示す斜視図である。
【図１４】図１３の被検面の上面図である。
【図１５】図１１〜図１４の方法で相対的な位置関係が明確になった複数の素子の各素子を構成する面のローカル座標系の相対位置を示す図である。
【図１６】図１１〜図１４の方法で、予め各素子を構成する面の偏心を導出しておいた素子からなる光学系を被検物として用いることにより、相対的な位置関係が明確になった複数の素子を構成する各面のローカル座標系の相対位置を示す図である。
【図１７】本発明に基づいて被検物に固定した基準ブロックを用いて非球面レンズを構成する被検面の偏心量を導出する方法を説明するための図である。
【図１８】図１７の方法で被検面が球面であった場合に、被検面のローカル座標系を導出するために加工したマークや被検物の外形を示す図である。
【図１９】２つのレンズ群とプリズムからなる被検物を説明するための図である。
【図２０】本発明に基づいて被検物に固定した基準ブロックを用いて図１９に示した２つのレンズ群とプリズムからなる被検物を構成する被検面の偏心量を導出する方法を説明するための図である。
【図２１】図２０に示した２つのレンズ群とプリズムについてそれぞれ各素子（レンズ、プリズム）を構成する各面のローカル座標系を説明するための図である。
【図２２】図２０の方法で相対的な位置関係が明確になった複数の群とプリズムの各素子を構成する面のローカル座標系の相対位置を示す図である。
【図２３】図２０の方法で予め各素子を構成する面の偏心を導出しておいた素子からなる光学系を被検物として用いることにより、相対的な位置関係が明確になった複数の素子を構成する各面のローカル座標系の相対位置を示す図である。
【図２４】本発明における光プローブの移動方法を説明するための図である。
【図２５】マークｖを加工しておいたサンプルの一例を用いて、マークの位置に対する各面のローカル座標系の相対位置を求める方法を説明する為の図である。
【図２６】マークｖを加工しておいたサンプルの別の一例を用いて、被検物に固定した基準ブロックを用いて複数の被検面の偏心量を算出する方法を説明する為の図である。
【図２７】本発明に基づいて被検物に固定した底面が多角形からなる角柱の基準ブロックを用いて複数の被検面の偏心量を算出する方法を説明する為の図である。
【図２８】本発明に基づいて被検物に固定した基準ブロックを用いて複数の素子の各素子を構成する被検面の偏心量を導出する方法を説明するための図中の、１つの素子の被検面と基準ブロックの１つの基準面に対して光プローブを走査することによりその被検面上にあるマークの位置、基準面の形状を測定する様子を示す斜視図である。
【図２９】図２８の被検面の上面図である。
【図３０】図２８の別の素子の被検面と基準ブロックの他の被検面に対して光プローブを走査することによりその被検面上にあるマークの位置、基準面の形状を測定する様子を示す斜視図である。
【図３１】図３０の被検面の上面図である。
【符号の説明】
Ｏ…被検物
Ｓ１、Ｓ２、Ｓ１−１、Ｓ２−１、Ｓ１−２、Ｓ１−３、Ｓ２−２、Ｓ２−３、Ｓ３−１、Ｓ３−２、ＳＬ１−１、ＳＰ３−２、ＳＬ２−５ …被検面
Ｐ１、Ｐ２、Ｐ３…プリズム
Ｌ１−１、Ｌ１−２、Ｌ２−１、Ｌ２−２、Ｌ２−３、Ｌ２−４、Ｌ２−５…レンズ
Ｇ１、Ｇ２…レンズ群
Ａ１、Ａ２、Ａ１−１、Ａ２−１、Ａ１−２、Ａ１−３、Ａ２−２、Ａ２−３、Ａ３−１、Ａ３−２、ＡＬ１−１−１、ＡＬ１−１−２、ＡＬ１−２−１、ＡＬ１−２−２、ＡＰ３−１、ＡＰ３−２、ＡＰ３−３、ＡＬ２−１−１、ＡＬ２−１−２、ＡＬ２−２−１、ＡＬ２−２−２、ＡＬ２−３−２、ＡＬ２−４−１、ＡＬ２−４−２、ＡＬ２−５−１、ＡＬ２−５−２…ローカル座標系
Ｗ…枠
Ｍ…基準マーク
Ｅ、Ｅ１、Ｅ２、ｅ…エッジ
Ｌ、Ｌ１、Ｌ２…曲線
Ｂ、Ｂ１、Ｂ２、Ｂ１−１、Ｂ２−１…有効エリア
Ｄ…基準ブロック
Ｈ、Ｈ１、Ｈ２…基準面
Ｃ…保持具
Ｆ…円
ｖ…マーク
１…被測定面
２…光プローブ
１１…レーザ
１２、１３、１４…ミラー
１５…対物レンズ
１６…移動機構
１７…光位置検出装置
１８…ＸＹステージ
２１…光源
２２…第１ピンホール
２３…ハーフミラー
２４…対物レンズ
２５…第２ピンホール
２６…光検出器
２７…移動機構
２８…ＸＹステージ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a three-dimensional coordinate measuring method, and in particular, a surface shape and a relative positional relationship of a plurality of surfaces based on an edge of an optical element or a mold used when manufacturing them by plastic molding, glass molding, or the like. And the like for a three-dimensional coordinate measuring method for obtaining the same.
[0002]
[Prior art]
Since the surface shape of an optical element such as a lens or a prism greatly affects the performance of an optical system, absolute surface shape measurement is an important issue in quality control in a manufacturing process of the element. As a method for measuring the surface shape of an optical element, an interferometer is conventionally used, but the interferometer is a relative comparison with a reference surface and cannot measure an absolute shape.
[0003]
As a method for measuring the absolute shape, a stylus-type shape measuring device is commercially available, but mainly measures a shape of a cross section orthogonal to an optical axis, and a two-dimensional surface shape measurement is performed. Therefore, it is not possible to correctly measure an asymmetric surface shape of the optical element. In addition, the mold has a similar problem.
[0004]
On the other hand, there is a three-dimensional measuring machine as a device capable of measuring the three-dimensional coordinates of the sample surface with high accuracy. However, since there is generally no absolute coordinate system of the device itself, there is a problem that an absolute shape cannot be measured.
[0005]
Under such circumstances, the present applicant measures edges or marks at the same time with a non-contact optical probe in Japanese Patent Application Nos. 2000-387334, 2001-296030, and 2001-299727, and determines a measured value by the edge or the like. A method has been proposed in which the absolute shape of an optical element is obtained by converting the coordinates into coordinates.
[0006]
[Problems to be solved by the invention]
However, in Japanese Patent Application No. 2000-387334 or the like, a method for obtaining a relative positional relationship between coordinate systems expressing the surface shape of an optical element or a mold has not been studied in detail.
[0007]
The present invention has been made in view of such a situation of the related art, and an object thereof is to provide a surface shape and a relative positional relationship between a plurality of surfaces based on an edge of an optical element or a mold of a test object. Is to provide a three-dimensional coordinate measuring method for obtaining the above.
[0008]
[Means for Solving the Problems]
A first three-dimensional coordinate measuring method of the present invention that achieves the above object sets a curve substantially along the edge near an edge on a test object, scans the curve in a direction substantially perpendicular to the edge, and scans the edge. The method is characterized by detecting a coordinate value of a position determined based on the coordinate value.
[0009]
A second three-dimensional coordinate measuring method according to the present invention measures a three-dimensional surface shape and an edge shape for each surface of a test object composed of a plurality of surfaces, and measures a common edge measurement value. And determining a relative positional relationship between the plurality of surfaces.
[0010]
In the third three-dimensional coordinate measuring method according to the present invention, the test object composed of a plurality of surfaces is relatively fixed to a reference element whose relative positional relationship between the reference surfaces is known, and The three-dimensional surface shape of each test surface and the shape of the reference element are measured in the same measurement coordinate system, and the coordinates of each reference plane of the reference element are associated with the surface shape data obtained from the measured value of the edge shape of the reference element. And performing the same coordinate transformation on the three-dimensional surface shape measurement value of each test surface, thereby obtaining a relative positional relationship between a plurality of test surfaces of the test object. is there.
[0011]
Here, `` the same measurement coordinate system '' means not only using a common coordinate system, but also using different coordinate systems when measuring the test surface and the reference surface, for example, and used for each measurement. If the relative positions of the coordinate systems are known, the positions of the two coordinate systems can be represented by one coordinate system, and such a case is also meant.
[0012]
A fourth three-dimensional coordinate measuring method according to the present invention is a three-dimensional coordinate measuring method for measuring three-dimensional coordinates of a surface to be measured with a non-contact optical probe. When moving, the non-contact optical probe at a specific measurement point is moved in a direction away from the surface to be measured by a predetermined minute distance, and then is separated from the design value of the surface to be measured by the minute distance and follows the design value. In this manner, the object is moved to the next measurement point, and the next measurement point is measured in that state.
[0013]
According to a fifth three-dimensional coordinate measuring method of the present invention, in a test object constituted by using a plurality of elements constituted by a plurality of surfaces, a reference element having a known relative positional relationship between a reference surface and a test object is used. Are relatively fixed, and the three-dimensional shape of at least one surface of each element of the test object and the reference element are respectively measured in the same coordinate system, and correspond to the surface shape data obtained from the measured value of the edge shape of the reference element. By converting the coordinates of each reference plane of the reference element and performing the same coordinate conversion also on the three-dimensional surface shape measurement value of each test surface, the relative positional relationship of at least one surface constituting each element can be determined. It is a method characterized by obtaining.
[0014]
According to the present invention, the relative position of each test surface in the design coordinate system (local coordinate system) with respect to the outer shape can be accurately obtained, and the relative positional relationship of the local coordinate system on a plurality of test surfaces can be clearly defined. It becomes possible to. Therefore, the relative amounts of eccentricity on the plurality of test surfaces can be known, and this can be reflected in elucidation, correction, and the like of the optical performance deterioration.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a three-dimensional coordinate measuring method of the present invention will be described based on embodiments with reference to the drawings.
[0016]
Examples of the three-dimensional measuring device used in the measuring method of the present invention include a non-contact three-dimensional measuring device of an autofocus type that measures the position of a test object with a non-contact optical probe, a non-contact three-dimensional measuring device of a confocal microscope type, and the like. There is. First, these principles will be described.
[0017]
FIG. 1 is a diagram schematically showing a configuration of an auto-focus type non-contact three-dimensional measuring machine (for example, JP-A-2000-146532). Laser light emitted from a laser 11 passes through mirrors 13 and 12, The light enters the objective lens 15, advances toward the focal plane of the objective lens 15 at the center of the optical axis, enters the measurement surface 1 of the test object O, is reflected, passes through the objective lens 15 again, and passes through the mirrors 12 and 13. , 14 to form an image on the optical position detecting device 17. When the focus of the objective lens 15 is out of focus on the surface 1 to be measured, the imaging position of the optical position detecting device 17 changes. Therefore, this position change is captured by the optical position detecting device 17, and the objective lens 15 is moved by the moving mechanism 16. The object is moved in the focusing direction, the height of the surface 1 to be measured in the Z-axis direction can be measured by the position of the objective lens 15 when the object is in focus, and the object of the XY stage 18 on which the object O is placed is mounted. The position of the XY plane can be determined from the position of the lens 15 with respect to the optical axis. In this way, the three-dimensional shape of the measurement surface 1 of the test object O can be measured.
[0018]
FIG. 2 is a diagram schematically showing a configuration of a non-contact three-dimensional measuring device of a confocal microscope type. Light emitted from a light source 21 irradiates a first pinhole 22 and passes through the first pinhole 22. The light is reflected by the half mirror 23, enters the objective lens 24, travels toward the image point position of the objective lens 24 at the center of the optical axis, enters the measurement surface 1 of the test object O, reflects, and returns. The light passes through the half mirror 23 through the objective lens 24, is arranged at a position conjugate with the first pinhole 22, passes through the second pinhole 25, and enters the photodetector 26. When the surface 1 to be measured is not at a position conjugate with the first pinhole 22, light emitted from the first pinhole 22 cannot pass through the second pinhole 25, so that the photodetector 26 does not detect light. The entire system is moved in the optical axis direction by the moving mechanism 27, and the height of the surface 1 to be measured in the Z axis direction can be measured by the position at which the light detector 26 detects light. The position of the XY plane can be known from the position of the XY stage 28 on which O is mounted with respect to the optical axis of the objective lens 24. In this way, the three-dimensional shape of the measurement surface 1 of the test object O can be measured.
[0019]
The light beam for detecting the position of the non-contact three-dimensional measuring machine as described above is called an optical probe. By scanning the measurement surface 1 of the test object O using the non-contact optical probe, measurement data representing the surface shape is obtained. Further, at the edge of the test object O, when the optical probe is scanned, the value of the height greatly changes before and after the sampling point. By defining a point at which the height value has changed by more than this threshold value as an edge portion, the position of the edge portion can be detected.
[0020]
Therefore, for example, in order to efficiently measure the circular edge E, it is necessary to input the approximate center coordinates and the approximate radius of the circle as shown in FIG. Here, the center coordinates may be substantially the center of the circle to be measured. Then, a circle F from which scanning of the optical probe for measuring the edge E is started is defined by the input center coordinates and radius. However, depending on the shape of the surface to be inspected, as shown in FIG. 3A, when scanning in a direction outside the center (in the case of a disk), the value of the input radius should be smaller than the radius of the circle of the object. Is also made slightly smaller so that the scanning start point is inside the circle of the test object.
[0021]
In addition, as shown in FIG. 3B, when scanning from the outside toward the center (in the case of a circular hole), the value of the input radius is made slightly larger than the radius of the circle of the test object, The scanning start point is set outside the circle of the test object.
[0022]
In the measurement, a plurality of scanning start points are set on the circle F, and scanning is performed in the direction of the edge E (outward in FIG. 1A, inward in FIG. 1B). The coordinates of the edge E are obtained by comparing the threshold values and the like. By fitting the coordinates of the edge E obtained by the scanning of the optical probe to a circle using, for example, the least squares method, it is possible to calculate the center coordinates, the roundness, and the like of the test object.
[0023]
However, when the shape of the edge of the surface to be inspected is a curve other than a circle or a straight line, the same measurement becomes difficult. For example, in the case of an optical element such as a prism having a free-form surface, a cylindrical surface, an anamorphic surface, an aspheric surface, and an eccentric spherical surface, the edge of the surface constituting the prism can be represented only by a straight line or a circle. It is not possible, and it becomes a curve represented by a polynomial.
[0024]
Hereinafter, an example of measuring the shape of an edge formed of an arbitrary curve with respect to such a test object will be described.
[0025]
A curve L that follows the shape of the curve indicating the edge E of the test object (prism) O as shown in FIGS. 4A and 4B is defined. FIG. 4A is a perspective view showing a state in which the shape of the surface and the shape of the edge are measured by scanning the optical probe 2 with respect to the test object O, and FIG. FIG. 3 is a top view of a test surface S1. Here, the shape of the curve L may be calculated from the design value of the shape of the edge E to be measured. Alternatively, as shown in FIG. 5, a user may input at least three or more points in the vicinity of the edge E to be measured, and define a line connecting these points smoothly as a curve L. At this time, when calculating the curve L, the curve L can be calculated by performing fitting using a polynomial, spline calculation, or the like. Note that the spline operation is an operation method for smoothly connecting a plurality of input points to obtain a curve L, and is attributed to obtaining a spline function. The spline functions are defined as different polynomial curves of order n at most within a small section, and they are as if they are connected as smoothly as possible to each other.
[0026]
Then, when measuring the coordinates of the edge E, a plurality of scanning start points on the defined curve L are set, and the optical probe 2 is scanned from each point in a direction substantially orthogonal to the curve L, and a threshold value is set. And the like, the coordinates of the edge E are obtained. At this time, if the curve L intersects with the edge E to be measured in the range of the edge E to be measured, scanning by the optical probe 2 becomes difficult, and the coordinates of the edge E cannot be measured accurately. In such a case, it is necessary to increase the number of input points used to calculate the curve L, or to increase the number of terms of the fitting polynomial. This makes it possible to easily measure the coordinates of the edge E composed of an arbitrary curve with a small input value.
[0027]
Also, the edges E1 and E2 in the test surface S1 and the surface shape measurement value in the effective area B of the test surface S1 are measured in the same measurement coordinate system using the same non-contact three-dimensional measuring machine, and the surface shape is measured. By fitting the data to the design equation and performing the coordinate transformation on the measured data of the edges E1 and E2, the design coordinate system (local coordinate system) (X, Y) of each surface with respect to the outer shape as shown in FIG. ) Can be accurately determined. Thus, the amount of eccentricity in the plane of the test surface S1 can be known, and can be reflected in elucidation of the cause of optical performance deterioration, correction, and the like.
[0028]
In FIG. 6, only the left and right edges E1 and E2 of the figure are measured, but all edges or only necessary edges may be measured. Further, the shapes of the edges E1 and E2 are not limited to curves, but may be arcs or straight lines. In this case, efficient measurement can be achieved by combining with the conventional edge measurement method (FIG. 3). In FIG. 6, a curve L1 is a curve defined along the edge E1, and a curve L2 is a curve defined along the edge E2.
[0029]
Here, examples of the test object O in the present invention include an arbitrary optical element such as a prism or a mold used when manufacturing such an optical element by plastic molding, glass molding, or the like. As such an optical element, there is an optical element using not only a spherical surface and a rotationally symmetric aspherical surface but also a refracting surface or a reflecting surface of a cylindrical surface, an anamorphic surface or a free-form surface. Here, there are various defining formulas for expressing the free-form surface, and one example is defined by the following formula. The Z axis of this definition formula is the axis of the free-form surface.
[0030]

Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.
[0031]
In the spherical term,
c: curvature of the vertex
k: conic constant (conical constant)
r = √ (X ² + Y ² )
It is.
[0032]
The free-form surface term is

Where C _j (J is an integer of 2 or more) is a coefficient.
[0033]
In general, the free-form surface does not have a symmetry plane in both the XZ plane and the YZ plane. However, by setting all odd-order terms of X to zero, a symmetry plane parallel to the YZ plane is obtained. Is a free-form surface where only one exists. By setting all the odd-order terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane exists.
[0034]
Next, a description will be given of a method of calculating the relative eccentricity of the plurality of surfaces constituting the edge by measuring the edge formed by the boundaries of the plurality of surfaces for each surface constituting the edge and combining them. Here, for example, a design coordinate system (local) of each surface of an optical element such as a prism formed by arranging a free-form surface, a cylindrical surface, an anamorphic surface, an aspherical surface, and a spherical surface eccentrically to each other is used. The case where the relative positional relationship of the coordinate system (coordinate system) is obtained will be described.
[0035]
With reference to FIG. 7, a method of calculating the eccentricity of the test surfaces S1, S2 sharing one edge E of the test object (prism) O will be described. FIG. 7A is a perspective view showing a state in which the optical probe 2 scans the surface S1 of the test object O to measure the shape of the surface and the shape of the edge, and FIG. FIG. 7C is a top view of the test surface S1, and FIG. 7C is a perspective view showing how the optical probe 2 scans the test surface S2 to measure the shape of the surface and the shape of the edge. d) is a top view of the test surface S2.
[0036]
First, as shown in FIG. 6, the shape measurement value of the edge E and the surface shape measurement value in the effective areas B1 and B2 are the same using the same non-contact three-dimensional measuring machine for each of the test surfaces S1 and S2. Measurement is performed in a measurement coordinate system, the surface shape data is fitted to the design values of the test surfaces S1 and S2, and the coordinate conversion is also performed on the measurement data of the edge E. The position of the edge E with respect to the local coordinate systems A1 and A2 to be represented is obtained.
[0037]
Further, coordinate conversion is performed so that each data of the edge E measured for each surface coincides. At this time, the edge measurement values of one surface may be fixed, and the other edge measurement values may be decentered and shifted so that the surface edges overlap. In the analysis, the least squares method may be used so that the measured values of both edges are on substantially the same curve.
[0038]
By executing the coordinate transformation obtained by this analysis also on the local coordinate systems A1 and A2 representing the test surfaces S1 and S2, the local coordinate system on a plurality of surfaces S1 and S2 as shown in FIG. It is possible to clarify the relative positional relationship between A1 and A2. Note that FIG. 8 shows an example in which the edge E has only two test surfaces, but the present invention is not limited to this, and the same applies to the relative position of a local coordinate system having three or more test surfaces. It can be obtained by a method. By these methods, the relative eccentricity on a plurality of surfaces can be known, and this can be reflected in elucidation of factors of optical performance deterioration, correction, and the like.
[0039]
Next, as shown in FIG. 9, the eccentricity of the two test surfaces S1 and S2 sharing the common edge E is determined by using an element (reference block) D which is a reference fixed to the element of the test object O. Then, a calculation method will be described. FIG. 9A shows the shape of the test surface S1 and the edge e of the reference surface H by scanning the optical probe 2 with respect to the test surface S1 of the test object O and one reference surface H of the reference block D. 9 (b) is a top view of the test surface S1, and FIG. 9 (c) is an optical probe for the test surface S2 and another reference surface H of the reference block D. 2 is a perspective view showing a state in which the shape of the test surface S2 and the shape of the edge e of the reference surface H are measured by scanning 2, and FIG. 9D is a top view of the test surface S2.
[0040]
The test object O is fixed and held integrally by the reference block D and the holder C, and the shape of each reference surface H of the reference block D and the corresponding test surfaces S1 and S2 corresponding thereto is the same non-contact 3. The measurement can be performed in the same measurement coordinate system using a dimension measuring machine.
[0041]
The surface shape data of each of the test surfaces S1 and S2 is subjected to fitting to the design values of each of the test surfaces S1 and S2, so that a local coordinate system A1 and a local coordinate system A1 representing the test surfaces S1 and S2 are obtained. The position of A2 is determined in advance.
[0042]
Also, when calculating the local coordinate system, the coordinate of the design shape of each surface to be inspected is coordinate-converted, and when the surface shape data and each coordinate-converted design shape are superimposed, coordinates that minimize the residual error are obtained. The analysis of the optimization for obtaining the conversion parameter may be performed.
[0043]
The shape of the reference block D should be such that at least two edges e or one edge e and the position of a point whose coordinates are known can be measured simultaneously with the measurement of each of the test surfaces S1 and S2 of the test object O. Is desirable. At this time, at least two edges e or one edge e used in the measurement and a point whose coordinates are known need to be such that the position of each reference plane H of the reference block D can be defined from the measurement results. There is. Further, at least the angle and length of the edge e measured at the same time as each of the measurement surfaces H are measured in advance with high accuracy and are known, and each reference surface defined by a measurement value from these known data is used. The relative position of H should be known.
[0044]
Note that the shape of the reference block D may be, for example, a polyhedron shape in which the test surfaces S1 and S2 are approximated by a plane according to the shape of the test object O. At this time, a polyhedron constituted by planes defined by the local coordinate systems A1 and A2 of the design values of the test surfaces S1 and S2 may be used. When the reference block D is formed of a plane, measurement can be performed with high accuracy and simplicity, and analysis can be easily performed on other curved surfaces. Further, by adopting such a shape, each reference plane H of the reference block D and each of the test surfaces S1 and S2 corresponding to the reference plane H can be held substantially horizontally. It becomes possible to measure easily.
[0045]
Next, a measuring method will be described. First, as shown in FIG. 9, the shape measurement value of the edge e of the reference block D and the surface shape measurement value in the effective areas B1 and B2 of the test object O are the same for each of the test surfaces S1 and S2. Measurement is performed in the same measurement coordinate system using a non-contact three-dimensional measuring machine. Also, as described later, when a mark v whose coordinate position in the local coordinate system on the surface to be measured is known is processed in an area other than the effective area, the same measurement coordinate is similarly applied. Measure with the system.
[0046]
When the surfaces S1 and S2 need to be turned upward due to, for example, a measuring machine, the object O is rotated for each measurement of each surface as shown in FIGS. 9 (a) to 9 (d). Need to be kept. Therefore, the test object O and the reference block D are rotated and fixed in a desired direction by using a rotation mechanism (not shown). At this time, the relative positional relationship between the test object O and the reference block D is not changed by rotation.
[0047]
The reference block D measures items such that the reference plane position can be obtained from the measured values of the reference block D in correspondence with the known measured values. FIG. 9 shows an example in which two edges e are measured for each reference plane H. From these data, it is possible to determine the relative position of the reference plane H of the reference block D.
[0048]
For example, in the measurement of the edge of each reference plane H of the test surfaces S1 and S2, the edge to be measured is assumed to include a ridge line which is the boundary of the reference plane constituting the reference block D, and further different edge portions are measured. Alternatively, the position of the ridge line and the position of the plane representing the reference plane may be obtained for each reference plane. Here, the position of the ridge line means the position of at least one vertex of the side of the reference plane indicated by the ridge line and the result of deriving a straight line expression representing the ridge line. In order to calculate the vertices, an intersection may be obtained from the measurement results of the shapes of the two edges forming the vertices in the reference plane. In addition, for example, a point whose positional relationship with the vertex of the reference plane is known can be measured, and from the measurement result of the point and the measurement result of the edge serving as the ridge, the position of the ridge and the reference plane are similarly represented. The position of the plane may be determined. At this time, a least square method or the like may be used for the analysis so that the measured value of the edge is substantially on a straight line. Furthermore, it is possible to determine the position of each reference plane by associating the derived plane with known measurement values (side length and side-to-side angle) of the reference block D. However, if the position of the plane and the position of the ridge line are known as each reference surface position, it is possible to derive relative values of the test surfaces S1 and S2 described later.
[0049]
Further, by measuring the shapes of the test surfaces S1 and S2 in the same measurement coordinate system, the relative positions of the reference surface H and the test surfaces S1 and S2 can be grasped for each of the test surfaces S1 and S2. It becomes possible.
[0050]
As will be described later, when a mark v whose coordinate position in the local coordinate system on the test surface is known is processed in an area other than the effective area, similarly to the surface shape, By measuring the mark position, the relative position between the reference plane H and the mark v on the test surfaces S1 and S2 can be grasped for each of the test surfaces S1 and S2.
[0051]
Further, the positions of the respective surfaces obtained from the measured values of the reference surfaces H are converted in accordance with the known data of the reference surfaces H constituting the reference block D, and the relative positional relationships of the respective surfaces are adjusted. At this time, it is necessary to perform coordinate conversion such as shift and rotation.
[0052]
For example, coordinate conversion is performed so that the positions of the ridges respectively derived from the measurement results of the respective reference planes H including the same ridge are spatially coincident. A parameter for performing coordinate transformation of rotation may be calculated such that each plane corresponds to a known value of the reference element (an angle formed by each reference plane forming the same ridge line with the reference element). Thus, the relative position of each reference plane H can be obtained using the known angle of the reference block D.
[0053]
By performing these conversions on the shape measurement data of each of the test surfaces S1 and S2 measured in the same measurement coordinate system as each reference surface, the relative positions of the test surfaces S1 and S2 can be calculated. Becomes possible.
[0054]
Further, as described later, when a mark v whose coordinate position is known in the local coordinate system on the surface to be measured is processed in an area other than the effective area, similarly to the surface shape, By measuring each mark position in the same measurement coordinate system as each test surface and performing the same conversion on those mark positions, the relative position of each mark v on the test surfaces S1 and S2 can be determined. It can be calculated.
[0055]
By executing the coordinate transformation obtained by this analysis also on the local coordinate systems A1 and A2 of each of the test surfaces S1 and S2, as shown in FIG. The relative positional relationship of A2 can be clarified. Although FIG. 10 shows an example in which only two surfaces constituting the edge E are shown, the present invention is not limited to this, and a relative position of a local coordinate system of three or more surfaces can be obtained by a similar method. . Further, in this embodiment, one reference plane of the reference block D is simultaneously measured with respect to one test surface. However, depending on the shape of the test object, one reference plane may be measured with respect to two or more test objects. May be measured simultaneously. By these methods, the relative eccentricity on a plurality of surfaces can be known, and this can be reflected in elucidation of factors of optical performance deterioration, correction, and the like.
[0056]
In addition, by performing the manufacturing based on the result of the present method, it is possible to manufacture a highly accurate optical element.
[0057]
With reference to FIGS. 11 to 14, the eccentric amount of each optical element of the test object O in which a plurality of optical elements (for example, prisms) are arranged in the frame W is fixed to the frame W holding the test object O. A method of calculating using a reference element (reference block) D will be described. At this time, the test object O is configured to be able to measure at least one surface configuration of each optical element in a certain direction. 11 to 14, the prism P1 and the prism P2 are arranged in the frame W, and the surface S1-1 constituting the prism P1 and the S2-2 constituting the prism P2 are outside, and the optical probe 2 is irradiated. By doing so, it is possible to measure each surface.
[0058]
FIG. 11 shows the shape of the test surface S1-1 and the edge e of the reference surface H by scanning the optical probe 2 on the test surface S1-1 of the prism P1 and one reference surface H of the reference block D. FIG. 12 is a top view of the test surface S1-1, and FIG. 13 is a view showing the test surface S2-1 of the prism P2 and another reference surface H of the reference block D. FIG. 14 is a perspective view showing how the shape of the test surface S2-1 and the shape of the edge e of the reference surface H are measured by scanning the optical probe 2 with the optical probe 2. FIG. 14 is a top view of the test surface S2-1. is there.
[0059]
The test object O is fixed and held integrally by the reference block D and the holder C, and the shapes of the reference surfaces H of the reference block D and the corresponding test surfaces S1-1 and S2-1 corresponding thereto are respectively defined. Measurement can be performed in the same measurement coordinate system using a non-contact three-dimensional measuring machine. The surface shape data of each of the test surfaces S1-1 and S2-1 is subjected to fitting to design values of each of the test surfaces S1-1 and S2-1 to obtain the test surfaces S1-1 and S2. The positions of the local coordinate systems A1-1 and A2-1 representing -1 are obtained in advance.
[0060]
Also, when calculating the local coordinate system, the coordinate of the design shape of each surface to be inspected is coordinate-converted, and when the surface shape data and each coordinate-converted design shape are superimposed, coordinates that minimize the residual error are obtained. The analysis of the optimization for obtaining the conversion parameter may be performed.
[0061]
The shape of the reference surface H is such that at least two edges e or one edge e and coordinates of which are known at the same time as the measurement of each of the surfaces S1-1 and S2-1 of the prisms P1 and P2 of the object O. Is desirably configured to be able to measure the position of. At this time, at least two edges e or one edge e used in the measurement and a point whose coordinates are known need to be such that the position of each reference plane H of the reference block D can be defined from the measurement results. There is. Further, at least the angle and length of the edge e measured at the same time as each measurement surface H are measured with high precision in advance, and the relative position of each reference surface H defined by the measurement value from these known data. So that you can understand.
[0062]
Note that the shape of the reference block D may be, for example, a polyhedral shape having a surface approximating each of the test surfaces S1-1 and S2-1 with a plane according to the shapes of the prisms P1 and P2 of the test object. Good. At this time, the shape may be a polyhedron having a plane defined by the local coordinate systems A1-1 and A2-1 of the design values of the test surfaces S1-1 and S2-1. When the reference block D is formed of a plane, measurement can be performed with high accuracy and simplicity, and analysis can be easily performed on other curved surfaces. The material may be glass or metal. Manufacturing with these materials enables processing with high surface accuracy, so that the angle of the reference surface can be measured with high accuracy. Further, since a sharp edge shape can be formed, highly accurate measurement of the reference surface can be performed.
[0063]
Next, a measuring method will be described. First, as shown in FIG. 11 to FIG. 14, the shape of the edge e of the reference block D and the respective test surfaces of the prisms P1 and P2 as the test object O are provided for each of the test surfaces S1-1 and S2-1. The surface shapes in the effective areas B1-1 and B2-1 of S1-1 and S2-1 are measured in the same measurement coordinate system using the same non-contact three-dimensional measuring machine. At this time, for example, the test surfaces S1-1 and S2-1 are set so that the test surfaces S1-1 and S2-1 are substantially perpendicular to the direction in which the optical probe 2 is incident, due to a measuring instrument. When it is necessary to turn the test object upward, as shown in FIGS. 11 to 14, it is necessary to rotate and hold the test object O for each measurement of each surface. Therefore, the test object O and the reference block D are rotated and fixed in a desired direction by using a rotation mechanism (not shown). At this time, the relative positional relationship between the test object O and the reference block D is not changed by rotation.
[0064]
At this time, if the reference block D has a polyhedral shape having a plane defined by the local coordinate systems A1-1 and A2-1 of the design values of the surfaces S1-1 and S2-1 to be tested, When measuring the test surfaces S1-1 and S2-1 of the object O and the reference surface of the reference block D, the test surfaces S1-1 and S2-1 of the test object O and the reference surface of the reference block D are measured. However, at the same time, it is possible to arrange them so as to be substantially perpendicular to the direction in which the optical probe 2 is incident, so that the measurement can be easily performed.
[0065]
The reference block D measures items such that the reference plane position can be determined from the measured values of the reference block D by making the reference block D correspond to a known measurement value such as the side length of each reference plane. 11 to 14 show examples in which two edges are measured for each reference plane H. From these measurement data, the position of the reference plane H of the reference block D can be obtained.
[0066]
Note that the same method as the example shown in FIG. 9 can be used to derive the position of the reference plane H. Thereby, the position of each reference plane H of the reference block D can be obtained. Further, by measuring the shapes of the test surfaces S1-1 and S2-1 in the same measurement coordinate system, the relative positions of the reference surface H and the test surfaces S1-1 and S2-1 can be determined for each test surface S1. -1 and S2-1.
[0067]
Further, the positions of the respective surfaces obtained from the measured values of the reference surfaces H are converted in accordance with the known data of the reference surfaces H constituting the reference block D, and the relative positional relationships of the respective surfaces are adjusted. At this time, it is necessary to perform coordinate conversion such as shift and rotation.
[0068]
Note that a method similar to the example shown in FIG. 9 can be used to determine the relative position of each surface. By performing these conversions on each of the test surfaces S1-1 and S2-1 measured in the same measurement coordinate system as each reference surface, the relative positions of the test surfaces S1-1 and S2-1 can be determined. It becomes possible to grasp.
[0069]
By performing the coordinate conversion obtained by this analysis on each of the local coordinate systems A1-1 and A2-1 of the test surfaces S1-1 and S2-1, different optical elements as shown in FIG. The relative positional relationship between the local coordinate systems A1-1 and A2-1 on the plurality of surfaces S1-1 and S2-1 constituting the (prisms P1 and P2) can be obtained.
[0070]
Although FIGS. 11 to 14 show an example composed of two prisms P1 and P2, the present invention is not limited to this, and the relative positions of three or more optical elements are obtained by the same method. It becomes possible. In addition, although an example has been described in which the surface to be measured is one for the optical elements (prisms P1 and P2), the invention is not limited to this, and a plurality of surfaces may be measured for each element. Thus, more eccentricity and dimensional information can be obtained. In this case, the number of reference planes of the reference block may be increased as necessary. Also, an example has been described in which the relative positions of different prisms are obtained as the test object. However, the test object is not limited to this, and may be a lens, a mold for an optical element, an aperture, a frame W, or the like. For example, in the case of a frame, the surface shape of the test surface may be measured. However, what can determine the position of the frame from the measured values may be measured. H may be measured in the same measurement coordinate system.
[0071]
If the relative position of the local coordinates of each surface of each prism is determined by, for example, the method shown in FIG. 9 before being incorporated into the frame W, the local coordinate system of each surface constituting the prism for each prism can be obtained. Since the relative positions are known, the results are obtained by associating the test surfaces S1-1 and S2-1 of the prisms P1 and P2 shown in FIG. 15 with the positions of the local coordinate systems A1-1 and A2-1. As shown in FIG. 16, the surfaces (S1-2, S1-3) other than S1-1 forming the prism P1 and the surfaces (S2-2, S2-3) other than S2-1 forming the prism P2. , The relative position of each surface in the local coordinate system (A1-2, A1-3, A2-2, A2-3) can be obtained. By these methods, the relative eccentricity of a plurality of elements can be known, and this can be reflected in elucidation of the cause of optical performance deterioration, correction, and the like. In addition, by performing the manufacturing based on the result of the present method, it is possible to manufacture a highly accurate optical system.
[0072]
Next, referring to FIG. 17, the eccentricity of S3-1 and S3-2 of the test surface arranged on the front and back sides of the test object O such as an aspherical lens is determined. A calculation method using an element (reference block) D serving as a reference fixed to the above will be described. FIG. 17A shows the shape and reference of the surface S3-1 of the test surface by scanning the optical probe 2 with respect to the test surface S3-1 of the aspherical lens O and one reference surface H of the reference block D. FIG. 17 (b) is a perspective view of the test surface S3-1, and FIG. 17 (c) is a perspective view of the test surface S3-1, and FIG. 17 (c) is a reference block showing the measurement of the shape of the edge e of the surface H. FIG. 9 is a perspective view showing a state in which the shape of S3-2 of the surface to be measured and the shape of an edge e of the reference surface H are measured by scanning the optical probe 2 with respect to another reference surface H of D.
[0073]
The test object O is integrally fixed and held by the reference block H and the holder C. The shapes of the reference surfaces H of the reference block D and the test surfaces S3-1 and S3-2 corresponding to the reference surfaces H are respectively defined. Measurement can be performed in the same measurement coordinate system using a non-contact three-dimensional measuring machine. The surface shape data of each of the test surfaces S3-1 and S3-2 is subjected to fitting to design values of each of the test surfaces S3-1 and S3-2, thereby obtaining the test surfaces S3-1 and S3. The positions of the local coordinate systems A1-1 and A2-1 representing -2 are obtained in advance.
[0074]
The shape of the reference block H is determined by measuring at least two edges e or at least one edge e and the position of a point whose coordinates are known at the same time as the measurement of each of the test surfaces S3-1 and S3-2 of the aspheric lens of the test object O. It is desirable to be configured so that can be measured. At this time, at least two edges e or one edge e used in the measurement and a point whose coordinates are known are such that the position of H can be defined on each reference plane of the reference block D from the measurement results. There is a need. Further, at least the angle and length of the edge e measured at the same time as each measurement surface H are measured with high precision in advance, and the relative position of each reference surface H defined by the measurement value from these known data. So that you can understand.
[0075]
Note that the shape of the reference block D may be, for example, a rectangular parallelepiped having a thickness of about the thickness of each of the test surfaces S3-1 and S3-2 of the test object O. At this time, two edges may be measured on each of the reference planes with the opposed plane as a reference plane. At this time, the length of each side of the reference block D, the parallelism between each reference plane, the angle (orthogonality) with the plane adjacent to the reference plane, the height between the reference planes, and the like are measured with high accuracy. It is desirable.
[0076]
Next, a measuring method will be described. First, as shown in FIG. 17, the shape of the edge e of the reference block D and the validity of each of the test surfaces S3-1 and S3-2 of the test object O are determined for each of the test surfaces S3-1 and S3-2. The surface shape of the area is measured using the non-contact three-dimensional measuring machine in the same measurement coordinate system. At this time, for example, when it is necessary to turn the test surfaces S3-1 and S3-2 upward so that the test surface is substantially perpendicular to the incident direction of the optical probe 2 due to a measuring instrument, for example, As shown in FIGS. 17A to 17C, it is necessary to rotate the test object O by approximately 180 ° for each measurement of each surface. At this time, the relative positional relationship between the test object O and the reference block D is not changed by rotation.
[0077]
The reference block D measures items such that the reference plane position can be determined from the measured values of the reference block D by making the reference block D correspond to a known measurement value such as the side length of each reference plane. FIG. 17 shows an example in which two edges are measured for each reference plane H. From these measurement data, the position of the reference plane H of the reference block D can be obtained. Note that the same method as the example shown in FIG. 9 can be used to derive the position of the reference plane H. Thereby, the position of each reference plane H of the reference block D can be obtained. Further, by measuring the shapes of the test surfaces S3-1 and S3-2 in the same measurement coordinate system, the relative positions of the reference surface H and the test surfaces S3-1 and S3-2 can be determined for each test surface S3. -1, It becomes possible to grasp every S3-2.
[0078]
Further, the positions of the respective surfaces obtained from the measured values of the reference surfaces H are converted in accordance with the known data of the reference surfaces H constituting the reference block D, and the relative positional relationships of the respective surfaces are adjusted. When the reference block D is a substantially rectangular parallelepiped, for example, the coordinates of the vertices of each reference plane and the inclination of each reference plane calculated by measurement may be made to correspond to the relative position of the vertices of the known data and the data of the parallelism. In FIG. 17, the shape of the edge of the ridge line serving as the boundary of the reference plane is not measured. However, if the relative positional relationship between the edges of each reference plane is known, analysis is possible. By performing these conversions on each of the test surfaces S3-1 and S3-2 measured in the same measurement coordinate system as each reference surface, the relative positions of the test surfaces S3-1 and S3-2 can be determined. It becomes possible to grasp. Also, in addition to the opposing reference planes, the relative positions of the reference planes that are in contact with the two reference planes are measured, and the results are made to correspond to the angles of the respective planes of the known reference block. Analysis for deriving the relative position may be performed.
[0079]
By performing the coordinate transformation obtained by this analysis also on each of the local coordinate systems A3-1 and A3-2 of each of the test surfaces S3-1 and S3-2, as shown in FIG. It is possible to clarify the relative positional relationship between the local coordinate systems A3-1 and A3-2 on the surfaces S3-1 and S3-2 constituting the aspheric lens. In addition, since the relative position of each test surface can be determined by analysis, it is possible to obtain information such as the thickness of the lens in addition to the eccentricity. Further, by performing manufacturing based on such information, it is possible to manufacture an optical element with high accuracy.
[0080]
When the shape of the test surface is aspherical, the position of the local coordinates can be obtained by performing fitting to the design value from the surface shape data of the test surface, but when the shape of the test surface is spherical, Even with this method, the position of the local coordinate system cannot be determined. In such a case, a mark M may be provided on the surface to be measured so that the position of the local coordinate system can be obtained by measuring the shape of the surface to be measured at the same time. In this case, if the relative position of the mark M with respect to the local coordinate system is known, the position of the local coordinate system can be derived from the measurement results of a plurality of marks. The shape of the mark is not limited as long as the above analysis is possible, and may be, for example, a cross as shown in FIG. 18A or a cylinder as shown in FIG. 18B. Further, if the above analysis can be performed from the outer shape, it is not necessary to process a mark or the like. For example, in the case of an oval-shaped outer shape as shown in FIG. 18C, if the relative position of the local coordinate system can be derived from the shape of the linear portion of the outer shape, the position of the vertex with the arc, and the like, The analysis for deriving the local coordinate system of the surface to be inspected from the measurement results of the above may be performed.
[0081]
Further, when the shape of the surface to be inspected is a spherical surface, for example, since the spherical center position can be calculated by fitting the surface shape data with a sphere, it is also possible to obtain the relative spherical center position of each surface. is there. At this time, in measuring the spherical test surface, it is desirable to measure, for example, a mark or an outer shape as shown in FIG. 18 in the same coordinate system.
[0082]
In the measurement of the outer shape, the shape is not limited to the oval shape as shown in FIG. 18C, but may be an ordinary circular outer shape. In this case, the position of the center of the outer shape can be obtained by fitting the measurement result of the outer shape with a circle. Thereby, for example, it is possible to obtain the relative position of the spherical center of each surface with respect to a reference position such as the position of the mark or the center of the outer shape. Similarly, when an aspherical surface is included, it is also possible to obtain an approximate spherical center position in addition to the local coordinate system by fitting the surface shape data of the aspherical surface to the spherical surface. As described above, by using this method, it is possible to measure the eccentricity of the test object having the rotationally symmetric optical surface.
[0083]
Next, referring to FIG. 20, the eccentricity of each optical element of the test object O in which a plurality of optical elements (for example, lenses and prisms) are arranged in a frame W as shown in FIG. The calculation method using the reference element (reference block) D fixed in the frame W will be described. At this time, the test object O is an optical system whose optical axis is bent by the prism. In addition, the test object O is configured so that the surface shape of a plurality of surfaces can be measured in a certain direction. For this reason, it is desirable that the frame W be configured so that the frame W does not collide with a member constituting the measuring instrument, for example, a lens that irradiates the optical probe 2 (not shown) when the surface to be measured is measured.
[0084]
In FIG. 19, the first lens group G1, the prism P3, and the second lens group G2 are arranged in the frame W, and the surface SL1-1 and the prism P3 that form the lens L1-1 of the first lens group G1 are formed. The surface SP3-2 to be formed and the surface SL2-5 to form the lens L2-5 of the second lens group G2 protrude outside, and the irradiation of the optical probe 2 enables measurement of each surface. I have.
[0085]
FIG. 20A shows the shape of the test surface SL1-1 and the edge e of the reference surface H by scanning the optical probe 2 with respect to the test surface SL1-1 and one reference surface H of the reference block D. FIG. 20 (b) is a perspective view showing how the shape of the target surface is measured. FIG. 20 (b) shows the surface to be detected by scanning the optical probe 2 with respect to the target surface SP3-2 and another reference surface H of the reference block D. FIG. 20C is a perspective view showing how to measure the shape of SP3-2 and the shape of the edge e of the reference plane H. FIG. FIG. 9 is a perspective view illustrating a state in which the shape of a test surface SL2-5 and the shape of an edge e of a reference surface H are measured by scanning a probe 2;
[0086]
The test object O is fixed and held integrally by the reference block H and the holder C, and each of the reference surfaces H of the reference block D and the corresponding test surfaces SL1-1, SP3-2, and SL2-5 corresponding thereto. Can be measured in the same measurement coordinate system using a non-contact three-dimensional measuring machine. Note that the surface shape data of each of the test surfaces SL1-1, SP3-2, and SL2-5 is subjected to fitting by applying the design values of the test surfaces SL1-1, SP3-2, and SL2-5, respectively. The positions of the local coordinate systems AL1-1-1, AP3-2, and AL2-5-2 representing the test surfaces SL1-1, SP3-2, and SL2-5 are determined in advance.
[0087]
Also, when calculating the local coordinate system, the coordinate of the design shape of each surface to be inspected is coordinate-converted, and when the surface shape data and each coordinate-converted design shape are superimposed, coordinates that minimize the residual error are obtained. The analysis of the optimization for obtaining the conversion parameter may be performed.
[0088]
The shape of the reference block D is such that at least two edges e or 1 are measured simultaneously with the measurement of the test surfaces SL1-1, SP3-2, and SL2-5 of the lenses L1-1 and L2-5 of the test object O and the prism P3. It is desirable to be configured to be able to measure the positions of two edges e and points whose coordinates are known. At this time, at least two edges e or one edge e used in the measurement and a point whose coordinates are known are such that the position of H can be defined on each reference plane of the reference block D from the measurement results. There is a need. Further, at least the angle and length of the edge e measured at the same time as each measurement surface H are measured with high precision in advance, and the relative position of each reference surface H defined by the measurement value from these known data. So that you can understand.
[0089]
Note that the shape of the reference block D may be, for example, a polyhedral shape having a surface approximating each of the test surfaces SL1-1, SP3-2, and SL2-5 with a plane according to the shape of the test object O. Good. At this time, the shape of a polyhedron having a plane defined by the local coordinate system AL1-1-1, AP3-2, and AL2-5-2 of the design value of each of the test surfaces SL1-1, SP3-2, and SL2-5. It may be.
[0090]
Next, a measuring method will be described. First, as shown in FIG. 20, the shape of the edge e of the reference block D and the surfaces SL1-1, SP3 of the test object O for each of the surfaces SL1-1, SP3-2, SL2-5 to be tested. -2, the surface shape in the effective area of SL2-5 is measured in the same measurement coordinate system using a non-contact three-dimensional measuring machine. At this time, for example, the surfaces SL1-1, SP3-2, SP3-5 to be inspected are substantially perpendicular to the direction of incidence of the optical probe 2 due to the measuring instrument. -2, when it is necessary to turn SL2-5 upward, as shown in FIGS. 20A to 20C, it is necessary to rotate and hold the test object O for each measurement of each surface. Therefore, the test object O and the reference block D are rotated and fixed in a desired direction by using a rotation mechanism (not shown). At this time, the relative positional relationship between the test object O and the reference block D is not changed by rotation.
[0091]
The reference block D measures items such that the reference plane position can be obtained from the measured values of the reference block D by associating them with known measurement values such as the lengths of the sides of each reference plane. FIG. 20 shows an example in which two edges are measured for each reference plane H. From these measurement data, the position of the reference plane H of the reference block D can be obtained. Note that the same method as the example shown in FIG. 9 can be used to derive the position of the reference plane H. Thereby, the position of each reference plane H of the reference block D can be obtained. Further, by measuring the shapes of the test surfaces SL1-1, SP3-2, and SL2-5 in the same measurement coordinate system, the relative positions of the reference surface H and the test surfaces SL1-1, SP3-2, and SL2-5 are measured. Position can be grasped for each of the test surfaces SL1-1, SP3-2, and SL2-5.
[0092]
Further, the positions of the respective surfaces obtained from the measured values of the reference surfaces H are converted in accordance with the known data of the reference surfaces H constituting the reference block D, and the relative positional relationships of the respective surfaces are adjusted. At this time, it is necessary to perform coordinate conversion such as shift and rotation. Note that a method similar to the example shown in FIG. 9 can be used to determine the relative position of each surface. By performing these conversions on each of the test surfaces SL1-1, SP3-2, and SL2-5 measured in the same measurement coordinate system as each reference surface, the test surfaces SL1-1, SP3-2, and SL2 are measured. The relative position of -5 can be ascertained.
[0093]
The coordinate conversion obtained by this analysis is also performed on each of the local coordinate systems AL1-1-1, AP3-2, and AL2-5-2 of the test surfaces SL1-1, SP3-2, and SL2-5. Then, the relative positional relationship between the local coordinate systems AL1-1-1, AP3-2, and AL2-5-2 in the plurality of planes SL1-1, SP3-2, and SL2-5 as shown in FIG. 22 is obtained. It becomes possible.
[0094]
In addition, it is desirable that the relative position of the local coordinates of each surface of each optical element arranged in the test object be obtained for each group or each prism before being incorporated in the frame W. FIGS. 21A to 21C show a lens group G1 (constituted of lenses L1-1 and L1-2), a prism P3, and a lens group G2 (lenses L2-1, L2-2, and L2) which constitute the test object. -3, L2-4, and L2-5) are shown for each surface. The eccentricity in the lens groups G1 and G2 can be derived by using an existing measuring instrument, and the eccentricity of the prism P3 can be derived by, for example, the method shown in FIG. From the derived result, the relative position of the local coordinate system for each surface can be known. For example, as shown in FIGS. 21A to 21C, the lens group G1 forms the lens L1-1. The relative positions of the local coordinate systems AL1-1-1 and AL1-1-2 of the surface and the local coordinate systems AL1-2-1 and AL1-2-2 of the surface forming the lens L1-2 are known. Further, for example, in the prism P3, the relative positions of the local coordinate systems AP3-1, AP3-2, and AP3-3 on the surface constituting the prism P3 can be known. In the lens group G2, the local coordinate systems AL2-1-1 and AL2-1-2 of the surface forming the lens L2-1, the local coordinate system AL2-2-1 and the local coordinate system AL2-2-1 of the surface forming the lens L2-2. AL2-2-2, a local coordinate system AL2-3-2 of a surface constituting the lens L2-3, a local coordinate system AL2-4-1 and AL2-4-2 of a surface constituting the lens L2-4. , The relative positions of the local coordinate systems AL2-5-1 and AL2-5-2 on the surface constituting the lens L2-5.
[0095]
At this time, since the relative position of each surface in the local coordinate system is known for each lens group and each prism, as shown in FIG. 20, each test surface SL1-1 of the lenses L1-1, L2-5, and the prism P3. , SP3-2, and SL2-5 are combined with the local coordinate systems AL1-1-1, AP3-2, and AL2-5-2, so that the surfaces other than the inspection surface SL1-1 that constitute the lens group G1 are combined. And local coordinate systems (AL1-1-1, AL1-1-2, AL1-2-1, and AL1-2-1) including surfaces other than SP3-2 constituting the prism P3 and surfaces other than SL2-5 constituting the lens group G2. AL1-2-2, AP3-1, AP3-2, AP3-3, AL2-1-1, AL2-1-2, AL2-2-1, AL2-2-2, AL2-3-2, AL2- 4-1, AL2-4-2, AL2-5-1, AL2-5 It can be used to determine the relative position of the two). By these methods, the relative eccentricity of a plurality of elements can be known, and this can be reflected in elucidation of the cause of optical performance deterioration, correction, and the like. In addition, by performing the manufacturing based on the result of the present method, it is possible to manufacture a highly accurate optical system.
[0096]
When measuring the shape of each surface to be measured, when it is necessary to arrange the surface so that the surface to be measured faces substantially upward, a rotation mechanism (not shown) is used. Since it is sufficient that the specimen can be fixed without changing the relative position, if such holding is possible, a rotating mechanism may not be used, and for example, the arrangement may be changed and fixed.
[0097]
In order to measure the three-dimensional surface shape of the surface 1 (S1, S2) of the test object O by scanning the optical probe 2 of the non-contact three-dimensional measuring device as shown in FIGS. Since it is difficult to continuously scan the entire surface of the test surface 1 in whole due to the measurement time and the like, it is usually practical to measure at discrete points in the measurement surface. With respect to the movement of the optical probe 2 between the discrete points, conventionally, as shown in FIG. 24B, the optical probe 2 in the state of (1) whose height was measured at a specific position is kept at the same height. Is moved horizontally while maintaining the position, and the next position is measured in the state of (2). However, in such a movement of the optical probe 2 between the measurement points, if the gradient of the surface 1 to be measured is steep, the objective lenses 15 and 24 projecting the optical probe 2 come into contact with the surface 1 to be measured and The test surface 1 or the objective lenses 15 and 24 may be damaged, or the distance from the test surface 1 may be too large, and the reflected light may not be taken into the objective lenses 15 and 24 again to make measurement impossible.
[0098]
Therefore, in the measurement method of the present invention, as shown in FIG. 24A, the optical probe 2 in the state of (1) whose height has been measured at a specific position is moved upward by a predetermined minute distance α. In the state of (2), after that, it is moved by a small distance α from the design shape of the test surface 1 along the shape, brought to the next measurement position, and brought into the state of (3). The height of the next measurement position is measured. Here, the movement from the state (2) to the state (3) may be performed at the shortest distance or along the plane of the design value + α. By adopting such a moving method of the optical probe 2, it is possible to avoid that the objective lenses 15 and 24 come into contact with the test surface 1 and that the reflected light cannot be taken. The minute distance α is 0 or more, and can be arbitrarily set as long as the reflected light from the test surface 1 can be captured by the objective lens of the non-contact three-dimensional measuring device.
[0099]
Next, a description will be given of a measuring method using a sample in which the mark v has been processed at a coordinate position specified by the local coordinate system on the surface of the test object O on the test surface.
[0100]
FIG. 25 is an example of a sample in which the mark v has been processed. As shown in FIG. 25, in the measurement method of the present invention, a sample in which a mark v is processed at a coordinate position specified by a local coordinate system on a test surface of a test object O may be used. In this case, the mark position is measured in the same measurement coordinate system when measuring the surface shape of the test surface, and the position of the test surface in the local coordinate system can be obtained from the measured value of each mark position. Therefore, when deriving the local coordinate system, analysis such as fitting or optimization is not required, and thus analysis is facilitated.
[0101]
Note that the mark shape is not limited to a shape or number as long as the above analysis is possible. For example, the shape may be a cylinder, a prism, a cone, a pyramid, a cross, an L shape, an intersection, a point, and the like. . Moreover, any of a convex shape and a concave shape may be used as long as the measurement can be performed with high accuracy. Further, it is desirable that the mark processing position is processed in a region other than the effective areas B1 and B2 of the optical system. For example, when the mark shape is a column, the mark position may be the center position of a circle having an outer shape on the upper surface. In the case of a cross shape, the position may be the intersection of each straight line.
[0102]
Note that each mark does not necessarily have to be in the same plane as the test surface, as long as the mark shape can be measured in the same measurement coordinate system when measuring the surface shape of the test surface. May be on the surface.
[0103]
FIG. 26 is another example of a sample in which the mark v has been processed. As shown in FIG. 26, in the measurement method of the present invention, a sample in which a mark v is processed at a coordinate position specified by a local coordinate system on a surface to be inspected of an object O may be used. In this case, the mark position is measured in the same measurement coordinate system when measuring the surface shape of the test surface, and the position of the test surface in the local coordinate system can be obtained from the measured value of each mark position. Therefore, the positions of the local coordinate systems A1 and A2 indicating the respective test surfaces are obtained from the measurement results of the respective marks v on the test surfaces S1 and S2.
[0104]
Further, the shape of the reference block may be a prism having a bottom surface made of a polyhedron, as shown in FIG. In this case, when holding the test object O, the test surfaces S1 and S2 and at least one surface forming the reference block D are held so as to be substantially horizontal. Here, the surfaces to be inspected S1 and S2 and the surface of the reference block D which is substantially horizontal are referred to as reference surfaces H.
[0105]
In FIG. 27, since the surfaces H1 and H2 forming the reference block are held substantially horizontally with the respective test surfaces S1 and S2, they are used as the reference surfaces H of the respective test surfaces. With this configuration, it is not necessary to manufacture a reference block according to the shape of the test object O, and the same reference block can be used for general purposes. In FIG. 27, the shape of the reference block is an octagonal prism, but the shape is not limited to this as long as the above-mentioned holding is possible.
[0106]
Next, referring to FIGS. 28 to 31, the eccentricity of each optical element of the test object O in which a plurality of optical elements (for example, prisms) are arranged in the frame W is calculated by using the frame W for holding the test object O. A second method of calculating by using a reference element (reference block) D fixed to is described below. At this time, in the test object O, in a certain direction, a mark position processed on at least one surface constituting each optical element can be measured.
[0107]
Note that the mark shape is not limited to a shape or a number as long as the above measurement is possible. For example, the shape includes a cylinder, a prism, a cone, a pyramid, a cross, an L shape, an intersection, a point, and the like. . Moreover, any of a convex shape and a concave shape may be used as long as the measurement can be performed with high accuracy. Further, it is desirable that the mark processing position is processed in an area other than the effective areas B1-1 and B2-1 of the optical system.
[0108]
28 to 31, the prism P1 and the prism P2 are arranged in the frame W, and the marks v processed on the surface S1-1 forming the prism P1 and the surface S2-1 forming the prism P2 are outward. By irradiating the optical probe, the shape of each mark can be measured, and as a result, the position of the mark v can be obtained.
[0109]
FIG. 28 shows a mark shape and a reference surface H on the test surface S1-1 by scanning the optical probe with respect to the test surface S1-1 of the prism P1 and one reference surface H of the reference block D. FIG. 29 is a top view of a test surface S1-1, and FIG. 30 is a view showing the test surface S2-1 of the prism P2 and another reference surface H of the reference block D. FIG. 31 is a perspective view showing how the shape of the mark on S2-1 of the test surface and the shape of the edge e of the reference surface H are measured by scanning the optical probe. It is a top view.
[0110]
The test object O is fixed and held integrally by the reference block H and the holder C, and the marks on the reference surfaces H of the reference block D and the corresponding test surfaces S1-1 and S2-1 corresponding thereto are provided. The mark positions are determined from the measured values of the mark shapes so that the shapes can be measured in the same measurement coordinate system using a non-contact three-dimensional measuring machine.
[0111]
The shape of the reference block is such that at least two edges e or one edge e and the position of a point whose coordinates are known at the same time as the measurement of each of the test surfaces S1-1 and S2-1 of the prisms P1 and P2 of the test object O. It is desirable to be configured so that can be measured. At this time, it is necessary that the position of H can be defined on each reference plane of the reference block D based on at least two edges e or one edge e used for the measurement and a point whose coordinates are known. Further, at least the angle and the length of the edge e measured at the same time as each measurement surface H are measured in advance with high accuracy, and the relative position of each reference surface H defined by the measurement value from these known data is determined. Make sure you know.
[0112]
Next, a measuring method will be described. By the same method as the example shown in FIGS. 11 to 14, the shape of the edge e of the reference block D and each of the prisms P1 and P2 as the test object O are provided for each of the test surfaces S1-1 and S2-1. Each mark v on the test surfaces S1-1 and S2-1 is measured using the same non-contact three-dimensional measuring machine in the same measurement coordinate system. At this time, if it is necessary to turn the test surfaces S1-1 and S2-1 upward so that the test surface is substantially perpendicular to the incident direction of the optical probe due to, for example, the relationship between the measuring instruments, FIG. As shown in FIGS. 28 to 31, it is necessary to rotate and hold the test object O for each measurement of each surface. Therefore, the test object O and the reference block D are rotated and fixed in a desired direction by using a rotation mechanism (not shown). At this time, the relative positional relationship between the test object O and the reference block D is not changed by rotation.
[0113]
Note that the position of the reference plane H can be derived using the same method as in the example shown in FIG. 9, whereby the position of each reference plane H of the reference block D can be obtained. Further, by measuring the position of each mark v on the test surfaces S1-1 and S2-1 in the same measurement coordinate system, the marks on the test surface H and the test surfaces S1-1 and S2-1 are measured. The relative position of v can be grasped for each of the test surfaces S1-1 and S2-1.
[0114]
For the mark v, for example, by using the same method as shown in FIG. 26, that is, by measuring the mark position using the same measurement coordinate system together with the shape measurement of each surface, and performing the same analysis, The relative position of the mark can be calculated together with the surface shape of each surface. Therefore, it is possible to derive a relative position between the surface shape of the surface to be measured and the mark position.
[0115]
Further, the positions of the respective surfaces obtained from the measured values of the reference surfaces H are converted in accordance with the known data of the reference surfaces H constituting the reference block D, and the relative positional relationships of the respective surfaces are adjusted. At this time, it is necessary to perform coordinate conversion such as shift and rotation.
[0116]
The coordinate transformation obtained by this analysis is also performed on each mark v on each of the test surfaces S1-1 and S2-1, so that the mark on each of the test surfaces S1-1 and S2-1 is converted. It is possible to grasp the relative position.
[0117]
In addition, before assembling into the frame W, if the mark position of each surface to be measured of each prism and the relative position of the local coordinate system are obtained by, for example, the method shown in FIG. The relative position between the surface mark and the local coordinate system is known.
[0118]
If the mark is processed to a coordinate position specified by the local coordinate system on the surface to be measured, the position of the local coordinate system can be easily calculated from the measurement result of each mark position. Thus, for example, the relative positions of the plurality of marks v on each surface constituting the prism and the local coordinate system can be determined by the method shown in FIG.
[0119]
However, analysis is possible even when the coordinate position of each mark in the local coordinate system of the test surface is unknown. In this case, when measuring the position of the mark, the shape of the surface to be measured is measured using the same measurement coordinate system. For the surface shape data, the position of the local coordinate system representing the surface to be measured is obtained by performing optimization analysis such that the residual when each of them is superimposed on each design value shape is minimized by, for example, coordinate transformation. Therefore, the relative position between the local coordinate system and the mark v can be known for each surface. Therefore, for example, the relative position of each mark v can be determined by the method shown in FIG. 26 together with the surface shape of each surface constituting the prism and the local coordinate system. In this case, even if the mark v is not on the same plane as the surface to be inspected, the same analysis is possible if the mark position can be measured in the same measurement coordinate system.
[0120]
Therefore, by associating these results with the positions of the same marks on the test surfaces S1-1 and S2-1 of the prisms P1 and P2 shown in FIG. 30, the prisms as shown in FIG. The local coordinate system (A1-A1) of each of the surfaces (S1-2, S1-3) other than S1-1 forming the P1 and the surfaces (S2-2, S2-3) other than the S2-1 forming the prism P2. 2, A1-3, A2-2, A2-3) can also be obtained.
[0121]
In the above analysis, for example, for each corresponding test surface, the mark position measured in FIG. 30 and the corresponding mark on each prism measured before incorporating the frame W are coordinate-transformed, and the Optimization analysis may be performed to calculate coordinate conversion parameters so that the sum of distances is minimized. Further, the coordinate transformation derived by this analysis may be performed on the local coordinate system of the test surface or the local coordinate system of another test surface, whose relative positional relationship with the mark position is known.
[0122]
By these methods, the relative eccentricity of a plurality of elements can be known, and this can be reflected in elucidation of the cause of optical performance deterioration, correction, and the like. Further, by performing the manufacturing based on the result of the present method, it is possible to manufacture a highly accurate optical system.
[0123]
In this method, it is necessary to measure the mark on the surface to be inspected before and after being incorporated in the frame W. However, when calculating the mark position, analysis such as fitting or optimization is not required. It is possible to reduce the influence of measurement errors before and after.
[0124]
Further, in the above analysis, a case where one test surface with a mark is used for each prism is shown, but the present invention is not limited to this. For example, one prism may be used on a plurality of test surfaces. The analysis may be performed using a certain mark. In this case, since the information on the correspondence of the mark positions increases, the accuracy of the calculated relative eccentricity of the plurality of elements improves.
[0125]
The above three-dimensional coordinate measuring method of the present invention can be configured, for example, as follows.
[0126]
[1] A curve substantially along the edge is set near the edge on the test object, and scanning is performed in a direction substantially orthogonal to the curve to detect a coordinate value at a position determined based on the edge. Three-dimensional coordinate measuring method.
[0127]
[2] The three-dimensional coordinate measuring method according to the above item 1, wherein the curve is defined by a polynomial.
[0128]
[3] The three-dimensional coordinate measuring method according to [1], wherein the curve is a curve defined by selecting a plurality of points near an edge and gently connecting the plurality of points.
[0129]
[4] The three-dimensional coordinate measuring method according to the above item 3, wherein a spline operation is used when the plurality of points are smoothly connected.
[0130]
[5] The three-dimensional coordinate measuring method according to the above [1], wherein at least one of the surfaces constituting the test object is a free-form surface.
[0131]
[6] The method for measuring three-dimensional coordinates according to [5], wherein the test object is an optical element in which at least one of the constituent surfaces is a free-form surface.
[0132]
[7] The method for measuring three-dimensional coordinates according to the above [5], wherein the test object is a mold for manufacturing an optical element in which at least one of the constituent surfaces is a free-form surface.
[0133]
[8] For a test object composed of a plurality of surfaces, a three-dimensional surface shape and an edge shape are measured for each surface, and the measured values of a common edge are made to correspond to each other. A three-dimensional coordinate measuring method, wherein a relative positional relationship is obtained.
[0134]
[9] The relative positional relationship of the plurality of surfaces is obtained by associating the measured values of the common edge measured for each different surface on substantially the same curve. 8. The method for measuring three-dimensional coordinates according to 8.
[0135]
[10] A local coordinate system is determined for each surface by applying the surface shape measurement value measured for each surface to the design value of the surface, and the common edge measurement value measured for one surface and the other surface 10. The relative positional relationship of the local coordinate system on a plurality of surfaces is obtained by performing coordinate conversion on the local coordinate system in correspondence with the measured value of the measured common edge. Dimensional coordinate measurement method.
[0136]
[10-1] By superimposing the surface shape measurement value measured for each surface and the design shape of each test surface subjected to coordinate conversion, optimization is performed to obtain a coordinate conversion parameter that minimizes the residual. A local coordinate system is determined for each surface, and coordinate conversion is performed on the local coordinate system so that the measured value of the common edge measured on one surface corresponds to the measured value of the common edge measured on another surface. 10. The three-dimensional coordinate measuring method according to claim 9, wherein the relative positional relationship of the local coordinate system on the plurality of surfaces is obtained.
[0137]
[11] The three-dimensional coordinate measuring method according to the above item 9, wherein at least one of the surfaces constituting the test object is a free-form surface.
[0138]
[12] The method for measuring three-dimensional coordinates according to the above item 11, wherein the test object is an optical element in which at least one of the constituent surfaces is a free-form surface.
[0139]
[13] The method for measuring three-dimensional coordinates according to the above item 11, wherein the test object is a mold for producing at least one of the constituent surfaces having a free-form surface.
[0140]
[14] A test object composed of a plurality of surfaces and a reference element having a known relative positional relationship between the reference surface are relatively fixed, and the three-dimensional surface shape of each test surface of the test object is determined. The shape of the reference element is measured in the same measurement coordinate system, and the coordinates of each reference plane of the reference element are converted in accordance with the surface shape data obtained from the measured values of the edge shape of the reference element. A three-dimensional coordinate measuring method, wherein a relative positional relationship between a plurality of test surfaces of a test object is obtained by performing the measurement on a three-dimensional surface shape of the test surface.
[0141]
[14-1] The test object composed of a plurality of surfaces, the reference element having a known relative positional relationship between the reference surface and the test object are relatively fixed, and each test surface of the test object is fixed. The three-dimensional surface shape and the reference element are measured in the same measurement coordinate system, and the coordinates of the reference surface of each reference element are converted in accordance with the surface shape data obtained from the measured values of the reference element. A three-dimensional coordinate measuring method, wherein a relative positional relationship among a plurality of test surfaces of a test object is obtained by performing the same also on a position of a mark on each test surface.
[0142]
[14-2] In a test object composed of a plurality of surfaces, a reference element having a known relative positional relationship between the reference surface and the test object is relatively fixed, and each test surface of the test object is fixed. The position of the mark above and the reference element are measured in the same measurement coordinate system, and the coordinates of the reference plane of each reference element are converted according to the surface shape data obtained from the measured values of the reference element, and the same coordinate conversion is performed. Is performed also on the positions of the marks on each of the test surfaces to determine the relative positional relationship between the plurality of test surfaces of the test object.
[0143]
[14-3] In a test object composed of a plurality of surfaces, a reference element having a known relative positional relationship with the reference surface and the test object are relatively fixed, and each test surface of the test object is fixed. The position of the mark above and the reference element are each measured in the same measurement coordinate system, and the coordinates of the reference plane of each reference element are converted in accordance with the surface shape data obtained from the measured value of the edge shape of the reference element. A three-dimensional coordinate measuring method, wherein the same coordinate transformation is performed also on the position of a mark on each test surface, thereby obtaining a relative positional relationship between a plurality of test surfaces of the test object.
[0144]
[15] In a test object constituted by using a plurality of elements constituted by a plurality of surfaces, a reference element having a known relative positional relationship with a reference surface and the test object are relatively fixed, and the test object is fixed. The three-dimensional shape of at least one surface of each element and the reference element are measured in the same coordinate system, and the coordinates of each reference plane of the reference element are determined in correspondence with the surface shape data obtained from the measured value of the edge shape of the reference element. The three-dimensional coordinate measurement is characterized by obtaining the relative positional relationship between at least one surface constituting each element by performing the same coordinate conversion on the three-dimensional surface shape measurement value of each test surface. Method.
[0145]
[15-1] In a test object constituted by using a plurality of elements constituted by a plurality of surfaces, a reference element having a known relative positional relationship with the reference surface and the test object are relatively fixed, and The three-dimensional shape of at least one surface of each element of the inspection object and the reference device are measured in the same measurement coordinate system, and the coordinates of the reference surface of each reference device are associated with the surface shape data obtained from the measured values of the reference device. And performing the same coordinate conversion on the three-dimensional shape measurement value of each surface to be measured, thereby obtaining a relative positional relationship of at least one surface constituting each element. Measuring method.
[0146]
[15-2] In a test object constituted by using a plurality of elements constituted by a plurality of surfaces, a reference element having a known relative positional relationship with the reference surface and the test object are relatively fixed, and The position of a mark on at least one surface to be inspected of each element of the inspection object and the reference element are each measured in the same measurement coordinate system, and each reference element is associated with the surface shape data obtained from the measured value of the reference element. By converting the coordinates of the reference plane and performing the same coordinate transformation also on the position of the mark on each test surface, thereby obtaining the relative positional relationship of at least one surface constituting each element. 3D coordinate measurement method.
[0147]
[15-3] In a test object constituted by using a plurality of elements constituted by a plurality of surfaces, a reference element having a known relative positional relationship with the reference surface and the test object are relatively fixed, and The position of the mark on at least one surface to be inspected of each element of the inspection object and the reference element are respectively measured in the same measurement coordinate system, and corresponding to the surface shape data obtained from the measured value of the edge shape of the reference element. By converting the coordinates of the reference surface of each reference element and performing the same coordinate conversion also on the position of the mark on each test surface, obtaining the relative positional relationship between at least one surface constituting each element A three-dimensional coordinate measuring method.
[0148]
[16] The shapes of the reference elements 14, 14-3, and 15 wherein the shape of the reference element is obtained by measuring at least two edges of the reference element or one edge and the position of a point whose coordinates are known. , 15-3.
[0149]
[17] The three-dimensional coordinate measuring method according to the above item 16, wherein an angle formed by each of the reference planes constituting the reference element is known.
[0150]
[18] The three-dimensional coordinate measuring method according to the above item 17, wherein the edge to be measured on the reference plane includes a ridge line composed of each reference plane.
[0151]
[19] The position of a ridge line composed of each reference plane and the position of a plane representing the reference plane are derived from measurement results of at least two edges of the reference plane or one edge and a point whose coordinates are known. 19. The three-dimensional coordinate measuring method according to the above item 18, wherein
[0152]
[20] The coordinates are converted so that the positions of the ridges respectively derived from the measurement results of the respective reference planes including the same ridge are spatially coincident with each other. 20. The three-dimensional coordinate measuring method according to claim 19, wherein a parameter for performing coordinate conversion is calculated such that each plane included in the plane corresponds to a known value of the reference element.
[0153]
[21] The three-dimensional coordinate measuring method according to the above item 20, wherein the coordinate conversion is performed on a measurement result of each test surface measured in the same measurement coordinate system as each reference surface.
[0154]
[22] The three-dimensional coordinates according to the above item 20, wherein the coordinate conversion is performed on a local coordinate system obtained from a measurement result of each test surface measured in the same measurement coordinate system as each reference surface. Measuring method.
[0155]
[23] A local coordinate system for each surface is obtained by applying the surface shape measurement value measured for each surface to the design value of the surface, and the three-dimensional surface of each test surface is determined with respect to the obtained local coordinate system. The coordinate conversion performed on the shape measurement value is performed to obtain a relative positional relationship of a local coordinate system on a plurality of test surfaces of the test object. 3. The method for measuring three-dimensional coordinates according to any one of 3.
[0156]
[23-1] Using a sample in which a mark has been processed at the coordinate position specified by the local coordinate system on each surface to be measured, a local coordinate system is obtained from the mark position measured for each surface and obtained. The coordinate conversion performed on each reference plane is performed on the local coordinate system to obtain a relative positional relationship of the local coordinate system on a plurality of test surfaces of the test object. Or the three-dimensional coordinate measuring method according to 14-2 or 15 or 15-2.
[0157]
[23-2] By superimposing the surface shape measurement value measured for each surface and the design shape of each coordinate-converted test surface, optimization is performed to find a coordinate conversion parameter that minimizes the residual error. By calculating a local coordinate system for each surface, and performing a coordinate transformation on each of the reference planes with respect to the obtained local coordinate system, the relative coordinates of the local coordinate system on a plurality of test surfaces of the test object are obtained. The three-dimensional coordinate measuring method as described in the above item 14 or 14-2, 15 or 15-2, characterized by finding a suitable positional relationship.
[0158]
[24] The three-dimensional coordinate measuring method according to any one of the above items 14, 14-3, 15, and 15-3, wherein at least one of the surfaces constituting the test object is a free-form surface.
[0159]
[25] The three-dimensional coordinates according to any one of the above 14, 14-3, 15, and 15-3, wherein the test object is an optical element in which at least one of the constituent surfaces is a free-form surface. Measuring method.
[0160]
[26] The method of measuring a three-dimensional coordinate according to the above item 24, wherein the test object is a mold for manufacturing at least one of the constituent surfaces is a free-form surface.
[0161]
[27] The three-dimensional coordinate measuring method according to any one of the above items 14, 14-3, 15, and 15-3, wherein the reference plane constituting the reference element is formed by a plane. .
[0162]
[27-1] The three-dimensional coordinate measuring method as described in the above item 14 or 14-3, 15 or 15-2, wherein the reference element is a prism having a polygonal bottom surface.
[0163]
[28] The three-dimensional coordinate measuring method according to any one of the above 14, 14-3, 15, and 15-3, wherein the shape of the reference element is a polyhedron having a configuration in which the surface to be measured is approximated by a plane. .
[0164]
[29] The reference element according to any one of the above items 14, 14-3, 15, and 15-3, wherein the shape of the reference element is a polyhedron formed by a plane defined by a local coordinate system of the surface to be measured. 3D coordinate measuring method.
[0165]
[30] The method for measuring three-dimensional coordinates according to any one of the above items 14, 14-3, 15, and 15-3, wherein the reference element is made of glass.
[0166]
[31] The method for measuring three-dimensional coordinates according to any one of the above items 14, 14-3, 15, and 15-3, wherein the reference element is made of metal.
[0167]
[32] The method for measuring three-dimensional coordinates according to any one of the above 14, 14-3, 15, and 15-3, wherein the test object and the reference element are held by a jig having a rotating mechanism.
[0168]
[33] Perform measurement using a non-contact optical probe. At that time, to move the non-contact optical probe from a specific measurement point to the next measurement point, a non-contact optical probe at a specific measurement point Move in the direction away from the surface to be measured by a minute distance, then move from the design value of the surface to be measured by a minute distance along the design value, and move to the next measurement point. 33. The three-dimensional coordinate measuring method according to any one of the above items 1 to 32, wherein the measuring points are measured.
[0169]
[34] The three-dimensional coordinate measuring method as described in 15 or 15-3 above, wherein the relative positional relationship between the respective surfaces constituting the respective elements constituting the test object is known.
[0170]
[35] The three-dimensional coordinate measuring method according to the above item 16, wherein the test object constituted by using a plurality of elements constituted by a plurality of surfaces is held by a frame.
[0171]
[36] The method for measuring three-dimensional coordinates according to the above item 16, wherein the frame for holding the test object is configured to irradiate light to the test surface.
[0172]
[37] The method of measuring a three-dimensional coordinate according to description 15 or 15-3, wherein the test object has a rotationally symmetric optical surface.
[0173]
[38] The method for measuring three-dimensional coordinates according to Note 15 or 15-3, wherein the test object has a bent optical axis.
[0174]
[39] In a three-dimensional coordinate measuring method for measuring three-dimensional coordinates of a surface to be measured with a non-contact optical probe, when the non-contact optical probe is moved from a specific measurement point to the next measurement point, a specific measurement point is used. The non-contact optical probe is moved in a direction away from the surface to be measured by a predetermined minute distance, and then moved from the design value of the surface to be measured by a minute distance along the design value to the next measurement point. A three-dimensional coordinate measuring method, wherein the method is moved and a next measurement point is measured in that state.
[0175]
[40] A measuring machine using the three-dimensional coordinate measuring method according to any one of the above 1 to 39.
[0176]
[41] The one measured by the three-dimensional coordinate measuring method according to any one of the above items 1 to 39.
[0177]
【The invention's effect】
As is apparent from the above description, according to the three-dimensional coordinate measuring method of the present invention, the relative position of each test surface in the design coordinate system (local coordinate system) with respect to the outer shape can be accurately obtained. It is possible to clarify the relative positional relationship of the local coordinate system on the test surface. Therefore, the relative amounts of eccentricity on the plurality of test surfaces can be known, and this can be reflected in elucidation, correction, and the like of the optical performance deterioration.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of an auto-focus type non-contact three-dimensional measuring machine usable in the present invention.
FIG. 2 is a diagram schematically showing a configuration of a confocal microscope type non-contact three-dimensional measuring device usable in the present invention.
FIG. 3 is a diagram for explaining a method of measuring a circular edge portion.
FIG. 4 is a diagram for explaining a method of measuring an edge shape according to the present invention.
FIG. 5 is a diagram for explaining a method of setting a curve indicating a scanning start point when measuring the shape of an edge.
FIG. 6 is a diagram for explaining a method for obtaining a relative position of each surface in a local coordinate system with respect to an outer shape according to the present invention.
FIG. 7 is a diagram for explaining a method of calculating the eccentricity of a plurality of test surfaces sharing one edge of the test object according to the present invention.
8 is a diagram showing a local coordinate system of a plurality of surfaces whose relative positional relationship has been clarified by the method of FIG. 7;
FIG. 9 is a diagram for explaining a method of calculating eccentricities of a plurality of test surfaces using a reference block fixed to a test object according to the present invention.
10 is a diagram showing a local coordinate system of a plurality of surfaces whose relative positional relationship has been clarified by the method of FIG. 9;
FIG. 11 is a diagram for explaining a method of deriving an eccentric amount of a test surface forming each element of a plurality of elements using a reference block fixed to a test object according to the present invention; FIG. 4 is a perspective view showing a state in which the shape of the test surface and the shape of the edge of the reference surface are measured by scanning the optical probe with respect to the test surface of the element and one reference surface of the reference block.
FIG. 12 is a top view of the test surface in FIG. 11;
FIG. 13 illustrates how the shape of the test surface and the shape of the edge of the reference surface are measured by scanning the optical probe with respect to the test surface of another element in FIG. 11 and another reference surface of the reference block. FIG.
FIG. 14 is a top view of the test surface of FIG.
FIG. 15 is a diagram showing a relative position in a local coordinate system of a surface constituting each element of a plurality of elements whose relative positional relationship has been clarified by the methods of FIGS. 11 to 14;
FIG. 16 is a view illustrating a method of using FIGS. 11 to 14, in which the relative positional relationship is clearly defined by using, as a test object, an optical system including elements in which the eccentricity of a surface constituting each element is derived in advance. FIG. 7 is a diagram showing relative positions of respective surfaces constituting a plurality of elements in a local coordinate system.
FIG. 17 is a diagram for explaining a method for deriving the amount of eccentricity of a test surface forming an aspheric lens using a reference block fixed to a test object according to the present invention.
18 is a diagram showing a mark processed to derive a local coordinate system of the test surface and an outline of the test object when the test surface is a spherical surface in the method of FIG. 17;
FIG. 19 is a diagram for explaining a test object including two lens groups and a prism.
20 is a diagram illustrating a method of deriving the amount of eccentricity of a test surface forming a test object including two lens groups and a prism illustrated in FIG. 19 using a reference block fixed to the test object according to the present invention. It is a figure for explaining.
21 is a diagram for describing a local coordinate system of each surface constituting each element (lens, prism) for the two lens groups and the prism shown in FIG. 20;
FIG. 22 is a diagram showing a relative position in a local coordinate system of a surface constituting each element of a plurality of groups and a prism, the relative positions of which are clarified by the method of FIG. 20;
FIG. 23 shows a plurality of elements whose relative positional relations have been clarified by using an optical system composed of elements in which the eccentricity of the surface constituting each element has been previously derived by the method of FIG. FIG. 3 is a diagram showing a relative position of each surface constituting an element in a local coordinate system.
FIG. 24 is a diagram illustrating a method of moving an optical probe according to the present invention.
FIG. 25 is a diagram for explaining a method of obtaining a relative position of a local coordinate system of each surface with respect to a mark position using an example of a sample in which a mark v has been processed.
FIG. 26 is a view for explaining a method of calculating eccentricities of a plurality of test surfaces using a reference block fixed to a test object, using another example of a sample in which a mark v has been processed. It is.
FIG. 27 is a diagram for explaining a method of calculating the eccentricity of a plurality of test surfaces using a reference block of a prism having a polygonal bottom surface fixed to the test object according to the present invention.
FIG. 28 is a diagram for explaining a method of deriving an eccentricity of a test surface forming each element of a plurality of elements using a reference block fixed to the test object according to the present invention; FIG. 5 is a perspective view showing a state in which the position of a mark on the surface to be measured and the shape of the reference surface are measured by scanning the optical probe with respect to the surface to be measured of an element and one reference surface of a reference block.
FIG. 29 is a top view of the test surface in FIG. 28;
30. The position of a mark on the surface to be measured and the shape of the reference surface are measured by scanning the optical probe with respect to the surface to be measured of another element in FIG. 28 and another surface to be measured of the reference block. FIG.
FIG. 31 is a top view of the test surface in FIG. 30;
[Explanation of symbols]
O… test object
S1, S2, S1-1, S2-1, S1-2, S1-3, S2-2, S2-3, S3-1, S3-2, SL1-1, SP3-2, SL2-5 ... test surface
P1, P2, P3 ... Prism
L1-1, L1-2, L2-1, L2-2, L2-3, L2-4, L2-5 ... lens
G1, G2 ... lens group
A1, A2, A1-1, A2-1, A1-2, A1-3, A2-2, A2-3, A3-1, A3-2, AL1-1-1, AL1-1-2, AL1- 2-1, AL1-2-2, AP3-1, AP3-2, AP3-3, AL2-1-1, AL2-1-2, AL2-2-1, AL2-2-2, AL2-3- 2, AL2-4-1, AL2-4-2, AL2-5-1, AL2-5-2 ... local coordinate system
W… frame
M: fiducial mark
E, E1, E2, e ... edge
L, L1, L2 ... curve
B, B1, B2, B1-1, B2-1 ... Effective area
D: Reference block
H, H1, H2: Reference plane
C: Holder
F ... yen
v… mark
1: Surface to be measured
2. Optical probe
11 ... Laser
12, 13, 14 ... mirror
15 ... Objective lens
16. Moving mechanism
17 ... Optical position detection device
18 XY stage
21 ... Light source
22 1st pinhole
23 ... Half mirror
24 Objective lens
25: 2nd pinhole
26 ... Photodetector
27. Moving mechanism
28 ... XY stage

Claims (7)

A curve substantially along the edge is set near the edge on the test object, and scanning is performed in a direction substantially orthogonal to the curve to detect a coordinate value of a position determined based on the edge. Dimensional coordinate measurement method. For a test object composed of a plurality of surfaces, a three-dimensional surface shape and an edge shape are measured for each surface, and a measurement value of a common edge is made to correspond to each other, so that a relative value of the plurality of surfaces is obtained. A three-dimensional coordinate measuring method characterized by determining a positional relationship. A test object composed of a plurality of surfaces and a reference element having a known relative positional relationship between the reference surface are relatively fixed, and the three-dimensional surface shape of each test surface of the test object and the reference element The shape is measured in the same measurement coordinate system, and the coordinates of each reference plane of the reference element are transformed according to the surface shape data obtained from the measured value of the edge shape of the reference element. A three-dimensional surface shape measurement value, thereby obtaining a relative positional relationship between a plurality of test surfaces of the test object. In a three-dimensional coordinate measuring method for measuring three-dimensional coordinates of a surface to be measured with a non-contact optical probe, when the non-contact optical probe is moved from a specific measurement point to the next measurement point, the non-contact at the specific measurement point The optical probe is moved in a direction away from the surface to be measured by a predetermined minute distance, and then moved from the design value of the surface to be measured by a minute distance along the design value to the next measurement point, A three-dimensional coordinate measuring method characterized by measuring the next measuring point in that state. In a test object configured by using a plurality of elements composed of a plurality of surfaces, a reference element and a test object whose relative positional relationship of a reference plane is known are relatively fixed, and each element of the test object is fixed. Measuring the three-dimensional shape of at least one surface of the reference element and the reference element in the same coordinate system, and converting the coordinates of each reference plane of the reference element according to the surface shape data obtained from the measured value of the edge shape of the reference element; A three-dimensional coordinate measuring method, wherein the same coordinate transformation is also performed on a three-dimensional surface shape measurement value of each test surface to determine a relative positional relationship between at least one surface constituting each element. A test object composed of a plurality of surfaces and a reference element having a known relative positional relationship between the reference surface are relatively fixed, and the position of a mark on each test surface of the test object and the reference element Are measured in the same measurement coordinate system, and the coordinates of the reference plane of each reference element are converted in correspondence with the surface shape data obtained from the measured values of the edge shape of the reference element. A three-dimensional coordinate measuring method, wherein a relative positional relationship between a plurality of test surfaces of a test object is obtained by performing the same at a mark position. In the test object configured by using a plurality of elements composed of a plurality of surfaces, the relative position relationship between the reference plane and the reference element having a known relative position and the test object are relatively fixed, and each of the test objects is The position of a mark on at least one test surface of each element and the reference element are measured in the same measurement coordinate system, and each reference element is associated with the surface shape data obtained from the measured value of the edge shape of the reference element. By converting the coordinates of the reference surface and performing the same coordinate conversion also on the position of the mark on each test surface, a relative positional relationship between at least one surface constituting each element is obtained. 3D coordinate measurement method.

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