JP2004239646A

JP2004239646A - Optical measuring unit

Info

Publication number: JP2004239646A
Application number: JP2003026488A
Authority: JP
Inventors: Sadao Noda; 貞雄野田
Original assignee: Sunx Ltd
Current assignee: Panasonic Industrial Devices SUNX Co Ltd
Priority date: 2003-02-03
Filing date: 2003-02-03
Publication date: 2004-08-26
Anticipated expiration: 2023-02-03
Also published as: JP4037280B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical measuring unit for measuring displacement and inclination with high accuracy. <P>SOLUTION: A photo acceptance unit 20 is subjected to reflected light from a work W by convergent light, and distance to the work W is measured based on a position signal Sb of a lens position detection coil 31 when a photo acceptance signal Sc from the photo acceptance unit 20 becomes the maximum in a control means 3. On the other hand, in inclination measurement, the distance d' between an imaging point on an image pickup surface of a CCD 23 and the center of the image pickup surface is obtained, and the inclination of the work W is measured from this distance d'. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、被測定対象物の変位及び傾きを検出するための光学測定装置に関する。
【０００２】
【従来の技術】
被測定対象物の変位及び傾きを測定する装置として特許文献１及び特許文献２が開示されている。
特許文献１の変位測定装置は三角測量の原理を用いて被測定対象物の変位及び傾きを測定するものであり、変位測定用光学系と傾き測定用光学系とを備えている。変位測定用光学系では、レンズにより収束された投光素子からの光を被測定対象物に対して斜めから投射し、反射光をレンズにより収束して撮像手段の撮像面に照射する構成とされており、その撮像面における光の照射位置により被測定対象物の変位を測定することができる。
また、傾き測定用光学系は、レンズにより平行光とされた投光素子からの光を被測定対象物に対して斜めから投射し、反射光をレンズにより収束して撮像手段の撮像面に照射する構成とされており、その撮像面における光の照射位置により被測定対象物の傾きを測定することができる。
【０００３】
一方、特許文献２の変位測定装置は投光素子からの光を被測定対象物に照射し、レンズにより集光された被測定対象物からの散乱光を変位測定用撮像手段に受光するとともに、正反射光をプリズムで反射させて傾き測定用撮像手段にて受光する構成とされている。これにより、変位測定用撮像手段における光の照射位置に基づいて被測定対象物の変位が測定されるとともに、傾き測定用撮像手段における光の照射位置に基づいて被測定対象物の傾きが測定されるのである。
【０００４】
【特許文献１】
特開平８−２４０４０８号公報
【特許文献２】
特開平１１−１５３４０７号公報
【０００５】
【発明が解決しようとする課題】
しかしながら、特許文献１の構成では被測定対象物に対して斜めから光を投射しているため、被測定対象物の距離によって被測定対象物上に照射される光の位置が変わることで正しい変位・傾き測定を行なうことができないという問題がある。さらに、投光素子が２つ必要とされることに伴って投光素子を制御する回路が複数必要となり、装置の大型化が避けられない。
また、特許文献２の構成では被測定対象物の距離によってプリズムにおける正反射光の照射位置が変位してしまうことから、傾き測定用撮像手段の光の照射位置が異なり、この結果傾きの測定値が変化して正しく傾き測定が行なわれないという問題がある。
【０００６】
本発明は上記のような事情に基づいて完成されたものであって、変位及び傾きを高精度に測定することができる光学測定装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】
上記の目的を達成するための手段として、請求項１の発明は、光を被測定対象物に投射し、その被測定対象物からの反射光に基づいて前記被測定対象物の変位及び傾きを測定するものであって、光を出射する投光手段と、前記投光手段からの光を平行光にするコリメータレンズと、前記コリメータレンズからの平行光の一部を収束光に変える収束レンズと、前記コリメータレンズからの平行光を収束光に変えるとともに、前記収束レンズからの光を平行光に変えることで前記被測定対象物の光照射面に前記収束光及び前記平行光を投射する対物レンズと、前記対物レンズと前記収束レンズとの配置関係は固定のままで前記対物レンズから出射した収束光の焦点位置を移動させるように前記対物レンズ及び前記収束レンズをそれぞれの中心軸に沿った方向に移動させるレンズ位置移動手段と、前記レンズ位置移動手段に駆動信号を与えて前記対物レンズ及び前記収束レンズを往復移動させる駆動制御手段と、前記対物レンズの位置に基づいて位置信号を出力するレンズ位置検出手段と、前記被測定対象物の光照射面で反射した光を前記コリメータレンズを通して受光し、受光量に応じた受光信号を出力する変位測定用受光手段と、前記変位測定用受光手段からの受光信号が最大とされたときのレンズ位置検出手段からの位置信号に基づいて前記被測定対象物の光照射面までの距離を検出する距離検出手段と、前記被測定対象物の光照射面で反射した光を前記対物レンズを通して撮像面に受光し、その撮像面における受光量に基づいて撮像信号を出力する傾き測定用撮像手段と、前記傾き測定用撮像手段からの前記撮像信号に基づいて前記被測定対象物の光照射面の傾きを検出する傾き検出手段とを備えたところに特徴を有する。
【０００８】
請求項２の発明は、光を被測定対象物に投射し、その被測定対象物からの反射光に基づいて前記被測定対象物の変位及び傾きを測定するものであって、光を出射する投光手段と、前記投光手段からの光を平行光にするコリメータレンズと、前記コリメータレンズからの平行光の一部を収束光に変える収束レンズと、開口を有し、前記収束レンズからの光を前記開口に通すとともに、前記コリメータレンズからの光を発散光に変える発散レンズと、前記発散レンズからの発散光を収束光に変えるとともに、前記収束レンズからの光を平行光に変えることで前記被測定対象物の光照射面に前記収束光及び前記平行光を投射する対物レンズと、前記対物レンズから出射した収束光の焦点位置を移動させるべく前記発散レンズをその中心軸に沿った方向に移動させるレンズ位置移動手段と、前記レンズ位置移動手段に駆動信号を与えて前記発散レンズを往復移動させる駆動制御手段と、前記発散レンズの位置に基づいて位置信号を出力するレンズ位置検出手段と、前記被測定対象物の光照射面で反射した光を前記コリメータレンズを通して受光し、受光量に応じた受光信号を出力する変位測定用受光手段と、前記変位測定用受光手段からの受光信号が最大とされたときのレンズ位置検出手段からの位置信号に基づいて前記被測定対象物の光照射面までの距離を検出する距離検出手段と、前記被測定対象物の光照射面で反射した光を前記対物レンズを通して撮像面に受光し、その撮像面における受光量に基づいて撮像信号を出力する傾き測定用撮像手段と、前記傾き測定用撮像手段からの前記撮像信号に基づいて前記被測定対象物の光照射面の傾きを検出する傾き検出手段とを備えたところに特徴を有する。
【０００９】
請求項３の発明は、請求項１又は請求項２に記載のものにおいて、前記収束レンズはその中心軸が前記コリメータレンズの中心軸に一致するように配されているところに特徴を有する。
【００１０】
請求項４の発明は、光を被測定対象物に投射し、その被測定対象物からの反射光に基づいて前記被測定対象物の変位及び傾きを測定するものであって、光を出射する投光手段と、前記投光手段からの光を平行光にするコリメータレンズと、前記コリメータレンズからの平行光の一部を発散光に変える発散レンズと、開口を有し、前記発散レンズからの発散光を前記開口に通すとともに、前記コリメータレンズからの平行光を収束光に変える収束レンズと前記収束レンズからの収束光が照射されるとともに、前記発散光を平行光に変えることで前記被測定対象物の光照射面に収束光及び平行光を照射する対物レンズと、前記対物レンズから出射した収束光の焦点位置を移動させるべく前記収束レンズをその中心軸に沿った方向に移動させるレンズ位置移動手段と、前記レンズ位置移動手段に駆動信号を与えて前記収束レンズを往復移動させる駆動制御手段と、前記収束レンズの位置に基づいて位置信号を出力するレンズ位置検出手段と、前記被測定対象物の光照射面で反射した光を前記コリメータレンズを通して受光し、受光量に応じた受光信号を出力する変位測定用受光手段と、前記変位測定用受光手段からの受光信号が最大とされたときのレンズ位置検出手段からの位置信号に基づいて前記被測定対象物の光照射面までの距離を検出する距離検出手段と、前記被測定対象物の光照射面で反射した光を前記対物レンズを通して撮像面に受光し、その撮像面における受光量に基づいて撮像信号を出力する傾き測定用撮像手段と、前記傾き測定用撮像手段からの前記撮像信号に基づいて前記被測定対象物の光照射面の傾きを検出する傾き検出手段とを備えたところに特徴を有する。
【００１１】
【発明の作用及び効果】
＜請求項１の発明＞
請求項１の発明では、投光手段から出射された光からコリメータレンズ、収束レンズ及び対物レンズにより平行光と収束光とを作り出してそれぞれ被測定対象物に照射する。そして、反射光を対物レンズ及びコリメータレンズを介して変位測定用受光手段にて受光し、その受光信号が最大とされたときのレンズ位置検出手段からの位置信号に基づいて被測定対象物の変位を測定する。また、反射光を対物レンズ及び収束レンズを介して傾き測定用撮像手段にて受光し、その撮像信号に基づいて被測定対象物の傾きを測定する。
これにより、変位及び傾き測定のための投光手段を１つにすることができるから、投光手段の制御装置を削減することができて光学測定装置の小型化を図ることができる。
また、対物レンズからの収束光及び平行光を被測定対象物の変位方向に沿った方向に投射することで、被測定対象物の距離に関係無く被測定対象物の一定の位置に光を照射することができ、もって、変位及び傾きの測定を正確に行なうことができる。
【００１２】
＜請求項２の発明＞
発散レンズのみを往復移動させるようにしているから、レンズ位置移動手段を小型化することができる。また、発散レンズの開口に収束レンズからの光を通すようにして対物レンズと収束レンズとの間隔を一定に保つようにしたことで、発散レンズの位置に関係無く対物レンズから平行光を出射することができる。
【００１３】
＜請求項３の発明＞
コリメータレンズと収束レンズとを一体的に形成することで、部品点数が減少し、装置の小型化・組付け工数の削減を図ることができる。
【００１４】
＜請求項４の発明＞
収束レンズのみを往復移動させるようにしているから、レンズ位置移動手段を小型化することができる。また、収束レンズの開口に発散レンズからの光の一部を通すようにしたことで、収束レンズの位置に関係無く対物レンズから平行光を出射することができる。
【００１５】
【発明の実施の形態】
＜第１実施形態＞
請求項１の発明に係る光学測定装置の一実施形態を図１によって説明する。
本実施形態の光学測定装置はいわゆる合焦点検出により金属や樹脂等の非測定対象物の変位を測定するとともに、オートコリメータの原理を用いてその傾きを測定するものである。その構成は図１に示す通りであり、レーザパワー制御回路１１からの出力信号によりレーザ光源１２（「投光手段」に相当）からレーザ光が出射され、この出射光がビームスプリッタ１３を透過してコリメータレンズ１４に至り、平行光に変えられてから１／４波長板１５及び対物レンズ１６を透過して板状のワークＷ（「被測定対象物」に相当）の表面に投射される。
【００１６】
また、コリメータレンズ１４と１／４波長板１５との間にはビームスプリッタ１７がその反射面の中央部をコリメータレンズ１４の中心軸と一致させて配されており、さらに１／４波長板１５と対物レンズ１６との間には収束レンズ１８が配されている。この収束レンズ１８は、コリメータレンズ１４よりも小径とされているとともに、その中心軸をコリメータレンズ１４の中心軸と一致させた状態で配置されている。
【００１７】
従って、コリメータレンズ１４からの平行光のうち中央部分の光が収束レンズ１８により収束光に変えられて発散した光が対物レンズ１６により平行光としてワークＷに照射されるとともに、収束レンズ１８を介さずに対物レンズに至った円筒状の平行光は対物レンズ１６により収束光とされてワークＷに照射される。
また、対物レンズ１６に入射する収束レンズ１８からの光のスポット径が常に一定となるように両者１６，１８間の距離Ｄ１は一定とされている。
【００１８】
対物レンズ１６及び収束レンズ１８は音叉１９Ａ（「レンズ位置移動手段」に相当）の先端部にそれぞれ取りつけられており、その軸部には制御手段３（「距離検出手段」及び「傾き検出手段」に相当）からの制御信号Ｓａに応じて動作する音叉振動用の励磁コイル１９Ｂ（「駆動制御手段」に相当）が配設されている。励磁コイル１９Ｂに制御手段３からの制御信号Ｓａが供給されると、音叉１９Ａが図面上下方向に振動することに伴って対物レンズ１６及び収束レンズ１８が光軸ＬＣの方向に往復移動されるようになっている。また、音叉１９Ａのうち対物レンズ１６を取りつけた部位の近傍には対物レンズ１６の位置を検出するレンズ位置検出コイル３１（「レンズ位置検出手段」に相当）が配設されており、このレンズ位置検出コイル３１からの位置信号Ｓｂが制御手段３に出力されるようになっている。
【００１９】
ワークＷの表面（「光照射面」に相当）で反射した対物レンズ１６からの収束光は、１／４波長板１５、コリメータレンズ１４を通ってビームスプリッタ１３にて反射されるとともに、受光面の前方にピンホール板２１を設けた受光素子２０（「変位測定用受光手段」に相当）に受光され、その受光信号Ｓｃが制御手段３に出力される。尚、対物レンズ１６からの収束光がワークＷの表面に焦点を結ぶと、その反射光がピンホール板２１のピンホール位置で結像し、受光素子２０での受光量が最大となる。一方、対物レンズ１６を透過した収束光がワークＷの表面に焦点を結んでいないときには、その反射光の受光量は著しく少なくなる。
【００２０】
一方、ワークＷの表面で反射した対物レンズ１６からの平行光は収束レンズ１８を通って平行光とされた後１／４波長板１５を通ってビームスプリッタ１７に至り、ビームスプリッタ１７で反射され、収束レンズ２２により収束されてＣＣＤ２３（「傾き測定用撮像手段」に相当）の撮像面に結像する。ＣＣＤ２３では、その結像された撮像面における受光量分布に基づいて結像点の位置情報たるアナログ信号をＣＣＤ駆動回路２４に出力し、ＣＣＤ駆動回路２４はアナログ信号をディジタル信号（「撮像信号Ｓｄ」に相当）に変換して制御手段３に出力する。
【００２１】
以下、上記構成の動作について説明する。
制御手段３は、受光素子２０からの受光信号Ｓｃ及びレンズ位置検出コイル３１からの位置信号Ｓｂを基にしてワークＷ表面の変位を測定する。具体的には、励磁コイル１９Ｂに制御手段３からの制御信号が供給されると、音叉１９Ａが図面上下方向に振動することに伴って対物レンズ１６及び収束レンズ１８が光軸ＬＣの方向に往復移動され、そのときの受光素子２０からの受光信号Ｓｃをモニタし、その受光信号Ｓｃが最大となったときのレンズ位置検出コイル３１からの位置信号Ｓｂを取り込む。そして、取り込んだ位置信号Ｓｂから対物レンズ１６の位置を検出し、この対物レンズ１６の位置と焦点距離ｆ１とからワークＷまでの距離を割り出す。以降、ワークＷが光軸ＬＣと直交する方向へ移動したときには、上記と同様の手順によりワークＷ表面までの距離を割り出すことでワークＷの変位を検出する。
【００２２】
また、制御手段３は受光素子２０からの受光信号Ｓｃが最大とされたときのＣＣＤ駆動手段２４からの撮像信号Ｓｄに基づいてワークＷの表面の傾きを検出する。例えば、ワークＷの表面が光軸ＬＣに対して直交した状態、即ち、傾きが無いときには（図中▲１▼の状態、以下、正規位置という。）、ワークＷからの反射光は収束レンズ１８を通って平行光とされてビームスプリッタ１７の中央部分に至り、このビームスプリッタ１７を反射した平行光は収束レンズ２２により収束されてＣＣＤ２３の撮像面の中央に結像する。
【００２３】
ここで、オートコリメータの原理により、
ｄ＝２（ｆ２）θ・・・・・式（１）
ｄ´＝ｄｆ３／ｆ１・・・式（２）
（ｄ´：ＣＣＤ２３の撮像面中央と結像点との距離ｄ：収束レンズ１８からの光の焦点位置と対物レンズ１６を透過した反射光の焦点距離とのずれ量ｆ１：収束レンズ１８の焦点距離ｆ２：対物レンズ１６を透過した反射光の焦点距離ｆ３：収束レンズ２２の焦点距離 θ：ワークＷの傾き角）
の関係が成り立つことを利用して、制御手段３では上記式（１）及び式（２）からワークＷの傾き角を演算することができる。従って、上記のように撮像面の中央に光が結像しているときには、ｄ´＝０となって、傾き角θは「０°」と測定される（図２参照）。
【００２４】
また、ワークＷが正規位置から角度θ傾いているときには（図中▲２▼の状態）、反射光は光軸ＬＣに対して２θ傾いて対物レンズ１６に向かう。収束レンズ１８からの平行光はビームスプリッタ１７の左よりに照射され、ＣＣＤ２３上には中央から上側にｄ´だけオフセットして結像するから、上記式に基づいてワークＷの傾き角θが測定される（図２参照）。
【００２５】
ここで、ワークＷが傾きθを維持したまま光軸ＬＣと直交する方向に変位した場合においても、ワークＷには常に対物レンズ１６からの平行光が照射されているので、対物レンズ１６からワークＷまでの距離ｆ１に関係無く常に撮像面の中央からｄ´離れた位置に結像されて正確な測定が維持される。
【００２６】
このように、本実施形態では、レーザ光源１２により変位測定及び傾き測定を行なうようにしているから、それぞれの測定用に光源を設ける必要が無く、装置の構成を簡略化することができる。
また、対物レンズ１６からの収束光及び平行光をワークＷの変位方向に沿った方向に投射しているから、ワークＷの距離に関係無く一定の位置に光を照射することができ、もって、正確に変位の測定を行なうことができる。
また、傾きを測定する際には、対物レンズ１６とワークＷとの距離に無関係にワークＷの傾きを正確に測定できる。
【００２７】
＜第２実施形態＞
請求項２の発明に係る光学測定装置の一実施形態について図３を参照して説明し、第１実施形態と同一の部分には同一の符号を付して重複する説明を省略し、同一の作用・効果についての説明も省略する。
本実施形態では１／４波長板１５と対物レンズ１６との間に発散レンズ４１が配されている。この発散レンズ４１は音叉１９Ａの一端部に取り付けられており、他端部の近傍には音叉振幅制御回路１９Ｃからの駆動信号に基づいて動作する音叉振動用の励磁コイル１９Ｂ（音叉振幅制御回路１９Ｃとともに「レンズ位置移動手段」を構成する）が配設されている。励磁コイル１９Ｂに駆動信号が与えられると、励磁コイル１９Ｂが励磁されることにより音叉１９Ａが図面上下方向に往復移動されるようになっている。これによって、対物レンズ１６に照射される発散レンズからの発散光のビーム径が変化することで、対物レンズ１６からの収束光の焦点位置が光軸ＬＣに沿って移動する。
また、発散レンズ４１の中央部分には開口が形成されており、この開口の中心部が光軸に一致するように配されて収束レンズ１８からの光が対物レンズ１６に向かって通過するようになっている。
【００２８】
本実施形態では、発散レンズ４１を往復移動させることで、対物レンズ１６からの収束光の焦点位置を変化させるようにしているから、第１実施形態のものと比べて、音叉１９Ａ及び励磁コイル１９Ｂを小型化することができる。
また、収束レンズ１８からの光を発散レンズ４１の開口を通して対物レンズ１６に照射するようにしているから、発散レンズ４１を移動させたとしても対物レンズ１６に照射される収束レンズ１８からの光のビーム径は一定に保たれる。このようにすることで、ビーム径を一定に保つために収束レンズ１８及び対物レンズ１６を移動させるための機構が不要となり、装置を一層小型化させることができる。
【００２９】
＜第３実施形態＞
本実施形態は図４に示すように、コリメータレンズ１４と収束レンズ１８との間にアキシコンレンズ対４２を配したところが第２実施形態と相違している。このアキシコンレンズ対４２は大きさの異なるアキシコンレンズ４２Ａ，４２Ｂが互いに曲面を向かい合わせた状態で配されており、４２Ｂが４２Ａよりも大きくされている。このアキシコンレンズ４２Ａ，４２Ｂ間の距離を変えることで、アキシコンレンズ４２Ｂの平坦面から出射される平行光のビーム径を変化させることができ、これに伴って、対物レンズから出射される平行光のビーム径を変化させられる。
微小なワークＷの傾きを測定する場合と、大きなワークＷの傾きを測定する場合とでは、要求される平行光のビーム径が異なっており、例えば微小なワークＷに対して、そのワークの表面よりも大きなビーム径の光を照射しても正確な傾きが測定されず、逆に大きなワークＷに対してビーム径の小さい光を照射すると、その表面粗さによって測定に影響を及ぼして正確に傾きが測定されないことがある。
これに対して本実施形態では、対物レンズ１６からの平行光のビーム径を変えることができるから大きさの異なる様々なワークＷに対して正確な傾き測定を行なうことができる。
【００３０】
＜第４実施形態＞
請求項４に係る本実施形態は、コリメータレンズ１４と１／４波長板１５との間に発散レンズ４３が配されており、また、１／４波長板１５と対物レンズ１６との間には中央部分に開口を有する収束レンズ４４が配されているとともに、この収束レンズ４４が音叉１９Ａの一端側に取り付けられているところが第２実施形態と異なっている（図５参照）。
コリメータレンズ１４からの平行光の一部は収束レンズ４４にて収束光とされる。また、コリメータレンズ１４からの平行光のその他の一部は発散レンズ４３によって発散光となり、収束レンズ４４の開口を通過して対物レンズ１６に照射される。そうすると、対物レンズ１６からは収束光及び平行光が出射されてこれらがワークＷの表面に照射される。また、収束レンズ４４は音叉１９Ａのよって光軸ＬＣに沿って往復移動しているから、これに伴って対物レンズ１６から照射される収束レンズ４４の焦点位置が光軸ＬＣに沿った方向に移動する。
【００３１】
本実施形態では、収束レンズ４４を往復移動させることで、対物レンズ１６からの収束光の焦点位置を変化させるようにしているから、第１実施形態のものと比べて、音叉１９Ａ及び励磁コイル１９Ｂを小型化することができる。
また、発散レンズ４３からの光を収束レンズ４４の開口を通して対物レンズ１６に照射するようにしているから、収束レンズ４４を移動させたとしても対物レンズ１６に照射される発散レンズ４３からの光のビーム径は略一定に保たれる。このようにすることで、ビーム径を一定に保つために発散レンズ４３及び対物レンズ１６を移動させるための機構が不要となり、装置を一層小型化させることができる。
【００３２】
＜他の実施形態＞
本発明は上記記述及び図面によって説明した実施形態に限定されるものではなく、例えば次のような実施形態も本発明の技術的範囲に含まれ、さらに、下記以外にも要旨を逸脱しない範囲内で種々変更して実施することができる。
（１）上記第１及び第２実施形態では、コリメータレンズ１４と収束レンズ１８とを別体で設けた構成としていたが、例えばコリメータレンズ１４と収束レンズ１８とを一体的に形成したものを用いても良い。このようにすれば、部品点数が削減されるとともに、装置の小型化・組付け工数の削減を図ることができる。
【図面の簡単な説明】
【図１】第１実施形態の光学測定装置の構成を示す模式図
【図２】傾き測定の測定方法を示した模式図
【図３】第２実施形態の光学測定装置の構成を示す模式図
【図４】第３実施形態の光学測定装置の構成を示す模式図
【図５】第４実施形態の光学測定装置の構成を示す模式図
【符号の説明】
１２…レーザ光源（投光手段）
１４…コリメータレンズ
１６…対物レンズ
１８…収束レンズ
１９Ａ…音叉
１９Ｂ…励磁コイル
２０…受光素子（変位測定用受光手段）
２３…ＣＣＤ（傾き測定用撮像手段）
３０…制御手段（距離検出手段、傾き検出手段）
３１…レンズ位置検出コイル（レンズ位置検出手段）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical measurement device for detecting a displacement and a tilt of an object to be measured.
[0002]
[Prior art]
Patent Documents 1 and 2 disclose a device for measuring the displacement and inclination of a measured object.
The displacement measuring device disclosed in Patent Document 1 measures the displacement and tilt of an object to be measured using the principle of triangulation, and includes an optical system for measuring displacement and an optical system for measuring tilt. In the displacement measuring optical system, the light from the light projecting element converged by the lens is projected obliquely to the object to be measured, and the reflected light is converged by the lens and irradiated to the imaging surface of the imaging means. Thus, the displacement of the object to be measured can be measured by the irradiation position of the light on the imaging surface.
The tilt measuring optical system projects the light from the light projecting element, which has been converted into parallel light by the lens, obliquely onto the object to be measured, converges the reflected light by the lens, and irradiates the light onto the imaging surface of the imaging means. The inclination of the object to be measured can be measured based on the light irradiation position on the imaging surface.
[0003]
On the other hand, the displacement measuring device disclosed in Patent Document 2 irradiates the object to be measured with light from the light projecting element, and receives the scattered light from the object to be measured condensed by the lens to the displacement measurement imaging means, The configuration is such that the specularly reflected light is reflected by the prism and received by the tilt measuring imaging means. Thus, the displacement of the object to be measured is measured based on the irradiation position of the light in the displacement measurement imaging unit, and the inclination of the measurement object is measured based on the irradiation position of the light in the inclination measurement imaging unit. Because
[0004]
[Patent Document 1]
JP-A-8-240408 [Patent Document 2]
JP-A-11-153407
[Problems to be solved by the invention]
However, in the configuration of Patent Literature 1, light is projected obliquely to the measured object, so that the position of the light irradiated on the measured object changes depending on the distance of the measured object, so that the correct displacement is obtained. -There is a problem that inclination measurement cannot be performed. Further, with the necessity of two light projecting elements, a plurality of circuits for controlling the light projecting elements are required, and an increase in the size of the apparatus is inevitable.
Further, in the configuration of Patent Document 2, the irradiation position of the regular reflection light on the prism is displaced depending on the distance of the object to be measured. And the tilt measurement cannot be performed correctly.
[0006]
The present invention has been completed based on the above circumstances, and an object of the present invention is to provide an optical measuring device capable of measuring displacement and tilt with high accuracy.
[0007]
[Means for Solving the Problems]
As means for achieving the above object, the invention according to claim 1 projects light onto an object to be measured, and calculates displacement and inclination of the object to be measured based on reflected light from the object to be measured. And a collimator lens that emits light, emits light, a collimator lens that converts the light from the light projector into parallel light, and a converging lens that converts part of the parallel light from the collimator lens into convergent light. An objective lens for projecting the convergent light and the parallel light onto a light irradiation surface of the object to be measured by changing the parallel light from the collimator lens into convergent light and changing the light from the convergent lens into parallel light. The objective lens and the convergent lens are moved to their respective central axes so as to move the focal position of the convergent light emitted from the objective lens while the arrangement relationship between the objective lens and the convergent lens remains fixed. Lens position moving means for moving the objective lens and the convergent lens in a reciprocating manner by providing a drive signal to the lens position moving means, and a position signal based on the position of the objective lens. A lens position detecting means for outputting, light receiving means for receiving light reflected on a light irradiation surface of the object to be measured through the collimator lens, and outputting a light receiving signal corresponding to a received light amount; Distance detecting means for detecting the distance to the light irradiation surface of the measured object based on the position signal from the lens position detecting means when the light receiving signal from the light receiving means is maximized; and A tilt measuring imaging unit that receives light reflected by the light irradiation surface on the imaging surface through the objective lens, and outputs an imaging signal based on the amount of light received on the imaging surface; Based on the imaging signals from the measuring imaging means having a characteristic at which a tilt detection means for detecting the inclination of the light irradiation surface of the object to be measured.
[0008]
The invention according to claim 2 is for projecting light onto the object to be measured, measuring the displacement and inclination of the object to be measured based on the reflected light from the object to be measured, and emitting the light. A light projecting means, a collimator lens for converting light from the light projecting means into parallel light, a convergent lens for converting a part of the parallel light from the collimator lens to convergent light, and an aperture, By passing light through the aperture, a diverging lens that converts light from the collimator lens into divergent light, and changing divergent light from the divergent lens into convergent light, and changing light from the convergent lens into parallel light. An objective lens for projecting the convergent light and the parallel light onto a light irradiation surface of the object to be measured, and a divergent lens along a central axis of the divergent lens for shifting a focal position of the convergent light emitted from the objective lens. Lens position moving means for moving the lens position moving means, drive control means for providing a drive signal to the lens position moving means to reciprocate the divergent lens, and lens position detecting means for outputting a position signal based on the position of the divergent lens; Light receiving means for receiving light reflected by the light irradiation surface of the object to be measured through the collimator lens, and outputting a light receiving signal corresponding to the amount of received light; Distance detecting means for detecting the distance of the object to be measured to the light irradiation surface based on the position signal from the lens position detecting means at the maximum, and light reflected by the light irradiation surface of the object to be measured Receiving an image through the objective lens on an imaging surface and outputting an imaging signal based on the amount of light received on the imaging surface; and Characterized in place and a tilt detection means for detecting the inclination of the light irradiation surface of the object to be measured based on the image signal.
[0009]
According to a third aspect of the present invention, in the first or second aspect, the converging lens is arranged such that a central axis thereof is aligned with a central axis of the collimator lens.
[0010]
According to a fourth aspect of the present invention, light is projected onto the object to be measured, and the displacement and inclination of the object to be measured are measured based on the reflected light from the object to be measured, and the light is emitted. A light projecting means, a collimator lens for converting light from the light projecting means into parallel light, a divergent lens for converting a part of the parallel light from the collimator lens into divergent light, and an aperture, The diverging light is passed through the aperture, the convergent lens that converts the parallel light from the collimator lens into convergent light, and the convergent light from the convergent lens are irradiated. An objective lens that irradiates convergent light and parallel light onto a light irradiation surface of an object, and a lens that moves the convergent lens in a direction along a central axis thereof to move a focal position of the convergent light emitted from the objective lens. Position moving means, drive control means for providing a drive signal to the lens position moving means to reciprocate the converging lens, lens position detecting means for outputting a position signal based on the position of the converging lens, and The light reflected from the light irradiation surface of the object is received through the collimator lens, and the light receiving means for displacement measurement for outputting a light receiving signal corresponding to the amount of received light, and the light receiving signal from the light receiving means for displacement measurement is maximized. Distance detecting means for detecting a distance of the object to be measured to a light irradiation surface based on a position signal from the lens position detecting means at the time of the time, and the objective lens which reflects light reflected by the light irradiation surface of the object to be measured. A tilt measuring imaging unit that receives an image on the imaging surface through and outputs an imaging signal based on the amount of light received on the imaging surface; and based on the imaging signal from the inclination measuring imaging unit. Serial characterized in was a tilt detection means for detecting the inclination of the light irradiation surface of the object to be measured.
[0011]
Function and effect of the present invention
<Invention of claim 1>
According to the first aspect of the present invention, a collimator lens, a converging lens, and an objective lens produce parallel light and convergent light from the light emitted from the light projecting means, and irradiate the object to be measured. Then, the reflected light is received by the displacement measuring light receiving means via the objective lens and the collimator lens, and the displacement of the measured object is determined based on the position signal from the lens position detecting means when the light receiving signal is maximized. Is measured. Further, the reflected light is received by the tilt measuring image pickup means via the objective lens and the convergent lens, and the tilt of the measured object is measured based on the image pickup signal.
Thus, the number of the light projecting means for measuring the displacement and the inclination can be reduced to one, so that the control device of the light projecting means can be reduced, and the size of the optical measuring device can be reduced.
In addition, by projecting convergent light and parallel light from the objective lens in the direction along the direction of displacement of the object to be measured, light is irradiated at a fixed position on the object to be measured regardless of the distance to the object to be measured. Therefore, the displacement and the inclination can be measured accurately.
[0012]
<Invention of Claim 2>
Since only the diverging lens is reciprocated, the size of the lens position moving means can be reduced. In addition, by allowing light from the converging lens to pass through the aperture of the diverging lens and keeping the distance between the objective lens and the converging lens constant, parallel light is emitted from the objective lens regardless of the position of the diverging lens. be able to.
[0013]
<Invention of Claim 3>
By integrally forming the collimator lens and the converging lens, the number of components can be reduced, and the device can be reduced in size and the number of assembling steps can be reduced.
[0014]
<Invention of Claim 4>
Since only the converging lens is reciprocated, the lens position moving means can be reduced in size. Further, since a part of the light from the diverging lens is allowed to pass through the opening of the converging lens, parallel light can be emitted from the objective lens regardless of the position of the converging lens.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
<First embodiment>
One embodiment of the optical measuring device according to the first aspect of the present invention will be described with reference to FIG.
The optical measuring device according to the present embodiment measures the displacement of a non-measurement object such as a metal or a resin by so-called focus detection, and measures the inclination of the object using the principle of an autocollimator. The configuration is as shown in FIG. 1. A laser light is emitted from a laser light source 12 (corresponding to "light projecting means") by an output signal from a laser power control circuit 11, and the emitted light passes through a beam splitter 13. Then, the light reaches the collimator lens 14, is converted into parallel light, passes through the 波長 wavelength plate 15 and the objective lens 16, and is projected on the surface of a plate-like work W (corresponding to “measured object”).
[0016]
A beam splitter 17 is disposed between the collimator lens 14 and the quarter-wave plate 15 such that the center of the reflection surface is aligned with the center axis of the collimator lens 14. A converging lens 18 is arranged between the lens and the objective lens 16. The converging lens 18 has a smaller diameter than the collimator lens 14 and is arranged with its central axis coincident with the central axis of the collimator lens 14.
[0017]
Therefore, of the parallel light from the collimator lens 14, the light at the central portion is changed to convergent light by the converging lens 18, and the divergent light is irradiated on the work W as parallel light by the objective lens 16, Instead, the cylindrical parallel light that has reached the objective lens is converged by the objective lens 16 and is applied to the workpiece W.
The distance D1 between the two lenses 16 and 18 is constant so that the spot diameter of the light from the converging lens 18 incident on the objective lens 16 is always constant.
[0018]
The objective lens 16 and the converging lens 18 are respectively attached to the tip of a tuning fork 19A (corresponding to "lens position moving means"), and the control means 3 ("distance detecting means" and "tilt detecting means") ), And an excitation coil 19B (corresponding to “drive control means”) for tuning fork vibration that operates in response to a control signal Sa from the control signal Sa. When the control signal Sa from the control means 3 is supplied to the exciting coil 19B, the objective lens 16 and the converging lens 18 reciprocate in the direction of the optical axis LC as the tuning fork 19A vibrates in the vertical direction in the drawing. It has become. A lens position detecting coil 31 (corresponding to "lens position detecting means") for detecting the position of the objective lens 16 is provided near the part of the tuning fork 19A where the objective lens 16 is mounted. The position signal Sb from the detection coil 31 is output to the control means 3.
[0019]
The convergent light from the objective lens 16 reflected on the surface of the work W (corresponding to the “light irradiation surface”) is reflected by the beam splitter 13 through the ４ wavelength plate 15 and the collimator lens 14, and the light receiving surface The light is received by a light receiving element 20 (corresponding to a “light receiving means for displacement measurement”) provided with a pinhole plate 21 in front of the device, and a light receiving signal Sc is output to the control means 3. When the convergent light from the objective lens 16 focuses on the surface of the work W, the reflected light forms an image at the pinhole position of the pinhole plate 21, and the amount of light received by the light receiving element 20 is maximized. On the other hand, when the convergent light transmitted through the objective lens 16 is not focused on the surface of the workpiece W, the amount of the reflected light received is significantly reduced.
[0020]
On the other hand, the parallel light from the objective lens 16 reflected on the surface of the work W is converted into parallel light through the converging lens 18, passes through the 波長 wavelength plate 15, reaches the beam splitter 17, and is reflected by the beam splitter 17. Then, the light is converged by the converging lens 22 and forms an image on an image pickup surface of a CCD 23 (corresponding to “image sensor for measuring tilt”). The CCD 23 outputs an analog signal, which is positional information of an imaging point, to the CCD driving circuit 24 based on the distribution of the amount of received light on the imaged imaging surface, and the CCD driving circuit 24 converts the analog signal into a digital signal (“imaging signal Sd And outputs the result to the control means 3.
[0021]
Hereinafter, the operation of the above configuration will be described.
The control unit 3 measures the displacement of the surface of the workpiece W based on the light receiving signal Sc from the light receiving element 20 and the position signal Sb from the lens position detecting coil 31. Specifically, when the control signal from the control means 3 is supplied to the excitation coil 19B, the objective lens 16 and the converging lens 18 reciprocate in the direction of the optical axis LC as the tuning fork 19A vibrates in the vertical direction in the drawing. The light-receiving signal Sc from the light-receiving element 20 at that time is monitored, and the position signal Sb from the lens position detection coil 31 when the light-receiving signal Sc becomes maximum is captured. Then, the position of the objective lens 16 is detected from the received position signal Sb, and the distance to the workpiece W is determined from the position of the objective lens 16 and the focal length f1. Thereafter, when the workpiece W moves in a direction orthogonal to the optical axis LC, the displacement of the workpiece W is detected by calculating the distance to the surface of the workpiece W in the same procedure as described above.
[0022]
Further, the control means 3 detects the inclination of the surface of the work W based on the imaging signal Sd from the CCD driving means 24 when the light receiving signal Sc from the light receiving element 20 is maximized. For example, when the surface of the work W is orthogonal to the optical axis LC, that is, when there is no inclination (state (1) in the figure, hereinafter, referred to as a normal position), the reflected light from the work W is converged by the converging lens 18. The light passes through the beam splitter 17 and reaches a central portion of the beam splitter 17. The parallel light reflected by the beam splitter 17 is converged by the converging lens 22 and forms an image at the center of the imaging surface of the CCD 23.
[0023]
Here, according to the principle of the autocollimator,
d = 2 (f2) θ (1)
d ′ = df3 / f1 Equation (2)
(D ': distance between the center of the imaging surface of the CCD 23 and the imaging point d: deviation amount between the focal position of the light from the converging lens 18 and the focal length of the reflected light transmitted through the objective lens 16 f1: the focal point of the converging lens 18 Distance f2: focal length of reflected light transmitted through objective lens 16 f3: focal length of converging lens 22 θ: tilt angle of workpiece W)
The control means 3 can calculate the inclination angle of the workpiece W from the above equations (1) and (2) using the fact that Therefore, when light is focused on the center of the imaging surface as described above, d ′ = 0, and the tilt angle θ is measured as “0 °” (see FIG. 2).
[0024]
When the workpiece W is inclined at an angle θ from the normal position (state (2) in the figure), the reflected light is inclined 2θ with respect to the optical axis LC toward the objective lens 16. The parallel light from the converging lens 18 is emitted from the left side of the beam splitter 17 and forms an image on the CCD 23 with the offset d 'from the center to the upper side. Therefore, the inclination angle θ of the work W is measured based on the above equation. (See FIG. 2).
[0025]
Here, even when the work W is displaced in the direction orthogonal to the optical axis LC while maintaining the inclination θ, the work W is always irradiated with the parallel light from the objective lens 16. Irrespective of the distance f1 to W, an image is always formed at a position d 'away from the center of the imaging surface, and accurate measurement is maintained.
[0026]
As described above, in the present embodiment, since the displacement measurement and the tilt measurement are performed by the laser light source 12, it is not necessary to provide a light source for each measurement, and the configuration of the apparatus can be simplified.
Further, since the convergent light and the parallel light from the objective lens 16 are projected in the direction along the displacement direction of the work W, it is possible to irradiate light at a fixed position regardless of the distance of the work W. The displacement can be measured accurately.
When measuring the tilt, the tilt of the work W can be accurately measured regardless of the distance between the objective lens 16 and the work W.
[0027]
<Second embodiment>
One embodiment of the optical measuring device according to the second aspect of the present invention will be described with reference to FIG. 3, and the same portions as those in the first embodiment will be denoted by the same reference numerals, without redundant description, and the same components will be omitted. The description of the operation and effect is also omitted.
In this embodiment, a diverging lens 41 is arranged between the quarter-wave plate 15 and the objective lens 16. The diverging lens 41 is attached to one end of the tuning fork 19A, and near the other end is an excitation coil 19B (a tuning fork amplitude control circuit 19C) for tuning fork vibration which operates based on a drive signal from the tuning fork amplitude control circuit 19C. Together with “lens position moving means”). When a drive signal is applied to the excitation coil 19B, the excitation coil 19B is excited so that the tuning fork 19A reciprocates in the vertical direction in the drawing. As a result, the beam diameter of the diverging light from the diverging lens applied to the objective lens 16 changes, so that the focal position of the convergent light from the objective lens 16 moves along the optical axis LC.
An opening is formed at the center of the diverging lens 41, and the center of the opening is arranged so as to coincide with the optical axis so that light from the converging lens 18 passes toward the objective lens 16. Has become.
[0028]
In the present embodiment, the focal position of the convergent light from the objective lens 16 is changed by reciprocating the diverging lens 41, so that the tuning fork 19A and the exciting coil 19B are different from those of the first embodiment. Can be reduced in size.
Further, since the light from the converging lens 18 is radiated to the objective lens 16 through the opening of the diverging lens 41, even if the diverging lens 41 is moved, the light from the converging lens 18 radiated to the objective lens 16 is The beam diameter is kept constant. This eliminates the need for a mechanism for moving the converging lens 18 and the objective lens 16 to keep the beam diameter constant, and can further reduce the size of the apparatus.
[0029]
<Third embodiment>
This embodiment differs from the second embodiment in that an axicon lens pair 42 is disposed between the collimator lens 14 and the converging lens 18 as shown in FIG. The axicon lens pair 42 has axicon lenses 42A and 42B having different sizes arranged with their curved surfaces facing each other, and 42B is larger than 42A. By changing the distance between the axicon lenses 42A and 42B, the beam diameter of the parallel light emitted from the flat surface of the axicon lens 42B can be changed. Accordingly, the parallel light emitted from the objective lens can be changed. The beam diameter of light can be changed.
The required beam diameter of the parallel light is different between the case where the inclination of the minute work W is measured and the case where the inclination of the large work W is measured. Even if a beam with a larger beam diameter is irradiated, an accurate tilt cannot be measured. Conversely, if a beam with a smaller beam diameter is irradiated on a large work W, the measurement will be affected by the surface roughness of the work W, and the measurement will be accurately performed. Tilt may not be measured.
On the other hand, in the present embodiment, since the beam diameter of the parallel light from the objective lens 16 can be changed, accurate tilt measurement can be performed on various works W having different sizes.
[0030]
<Fourth embodiment>
In the present embodiment according to claim 4, the diverging lens 43 is disposed between the collimator lens 14 and the quarter-wave plate 15, and the diverging lens 43 is disposed between the quarter-wave plate 15 and the objective lens 16. The second embodiment differs from the second embodiment in that a converging lens 44 having an opening in the center is provided and the converging lens 44 is attached to one end of the tuning fork 19A (see FIG. 5).
Part of the parallel light from the collimator lens 14 is converged by the converging lens 44. The other part of the parallel light from the collimator lens 14 is diverged by the diverging lens 43, passes through the aperture of the converging lens 44, and irradiates the objective lens 16. Then, the convergent light and the parallel light are emitted from the objective lens 16 and are irradiated on the surface of the work W. Further, since the converging lens 44 reciprocates along the optical axis LC by the tuning fork 19A, the focal position of the converging lens 44 irradiated from the objective lens 16 moves in the direction along the optical axis LC. I do.
[0031]
In the present embodiment, the focal position of the convergent light from the objective lens 16 is changed by reciprocating the converging lens 44, so that the tuning fork 19A and the exciting coil 19B are different from those of the first embodiment. Can be reduced in size.
Further, since the light from the diverging lens 43 is irradiated to the objective lens 16 through the opening of the converging lens 44, even if the converging lens 44 is moved, the light from the diverging lens 43 irradiated to the objective lens 16 is not affected. The beam diameter is kept substantially constant. By doing so, a mechanism for moving the diverging lens 43 and the objective lens 16 to keep the beam diameter constant becomes unnecessary, and the apparatus can be further miniaturized.
[0032]
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and furthermore, besides the following, within the scope not departing from the gist. Can be implemented with various modifications.
(1) In the first and second embodiments, the collimator lens 14 and the converging lens 18 are separately provided. However, for example, a lens in which the collimating lens 14 and the converging lens 18 are integrally formed is used. May be. In this way, the number of parts can be reduced, and the device can be reduced in size and the number of assembling steps can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a configuration of an optical measurement device according to a first embodiment. FIG. 2 is a schematic diagram illustrating a measurement method of tilt measurement. FIG. 3 is a schematic diagram illustrating a configuration of an optical measurement device according to a second embodiment. FIG. 4 is a schematic diagram illustrating a configuration of an optical measurement device according to a third embodiment. FIG. 5 is a schematic diagram illustrating a configuration of an optical measurement device according to a fourth embodiment.
12. Laser light source (light emitting means)
14 Collimator lens 16 Objective lens 18 Convergent lens 19A Tuning fork 19B Excitation coil 20 Light receiving element (light receiving means for displacement measurement)
23: CCD (imaging means for measuring tilt)
30 control means (distance detecting means, inclination detecting means)
31 ... Lens position detection coil (lens position detection means)

Claims

Projecting light to the measured object, to measure the displacement and inclination of the measured object based on the reflected light from the measured object,
Light emitting means for emitting light,
A collimator lens that converts light from the light projecting unit into parallel light,
A converging lens that converts a part of the parallel light from the collimator lens into convergent light,
An objective lens that projects the convergent light and the parallel light onto a light irradiation surface of the object to be measured by changing the parallel light from the collimator lens into convergent light, and changing the light from the convergent lens into parallel light. ,
The objective lens and the convergent lens are moved in directions along respective central axes so as to move the focal position of the convergent light emitted from the objective lens while the arrangement relationship between the objective lens and the convergent lens is fixed. Lens position moving means for causing
Drive control means for giving a drive signal to the lens position moving means to reciprocate the objective lens and the convergent lens,
Lens position detecting means for outputting a position signal based on the position of the objective lens,
Displacement measuring light receiving means for receiving light reflected on the light irradiation surface of the object to be measured through the collimator lens and outputting a light receiving signal according to the amount of received light,
Distance detecting means for detecting the distance to the light irradiation surface of the measured object based on the position signal from the lens position detecting means when the light receiving signal from the displacement measuring light receiving means is maximized,
Tilt measuring imaging means for receiving light reflected on the light irradiation surface of the object to be measured through the objective lens on the imaging surface, and outputting an imaging signal based on the amount of light received on the imaging surface;
An optical measuring device comprising: a tilt detecting unit configured to detect a tilt of a light irradiation surface of the measured object based on the imaging signal from the tilt measuring imaging unit.

Projecting light to the measured object, to measure the displacement and inclination of the measured object based on the reflected light from the measured object,
Light emitting means for emitting light,
A collimator lens that converts light from the light projecting unit into parallel light,
A converging lens that converts a part of the parallel light from the collimator lens into convergent light,
A diverging lens that has an opening and passes light from the converging lens through the opening, and converts light from the collimator lens to diverging light;
While changing the diverging light from the diverging lens into convergent light, an objective lens that projects the convergent light and the parallel light onto a light irradiation surface of the object to be measured by changing light from the converging lens into parallel light. ,
Lens position moving means for moving the divergent lens in a direction along the central axis thereof to move the focal position of the convergent light emitted from the objective lens,
Drive control means for giving a drive signal to the lens position moving means to reciprocate the divergent lens,
Lens position detection means for outputting a position signal based on the position of the diverging lens,
Displacement measuring light receiving means for receiving light reflected on the light irradiation surface of the object to be measured through the collimator lens and outputting a light receiving signal according to the amount of received light,
Distance detecting means for detecting the distance to the light irradiation surface of the measured object based on the position signal from the lens position detecting means when the light receiving signal from the displacement measuring light receiving means is maximized,
Tilt measuring imaging means for receiving light reflected on the light irradiation surface of the object to be measured through the objective lens on the imaging surface, and outputting an imaging signal based on the amount of light received on the imaging surface;
An optical measuring device comprising: a tilt detecting unit configured to detect a tilt of a light irradiation surface of the measured object based on the imaging signal from the tilt measuring imaging unit.

3. The convergent lens according to claim 1, wherein the diameter of the convergent lens is smaller than that of the collimator lens, and the central axis of the convergent lens coincides with the central axis of the collimator lens. Optical measuring device.

Projecting light to the measured object, to measure the displacement and inclination of the measured object based on the reflected light from the measured object,
Light emitting means for emitting light,
A collimator lens that converts light from the light projecting unit into parallel light,
A diverging lens that converts a part of the parallel light from the collimator lens into divergent light,
A converging lens having an opening, passing the diverging light from the diverging lens through the opening, changing the parallel light from the collimator lens to converging light, and irradiating the converging light from the converging lens with the diverging light An objective lens that irradiates convergent light and parallel light on the light irradiation surface of the object to be measured by changing the light into parallel light,
Lens position moving means for moving the convergent lens in a direction along its central axis to move the focal position of the convergent light emitted from the objective lens;
Drive control means for giving a drive signal to the lens position moving means to reciprocate the converging lens,
Lens position detecting means for outputting a position signal based on the position of the convergent lens,
Displacement measuring light receiving means for receiving light reflected on the light irradiation surface of the object to be measured through the collimator lens and outputting a light receiving signal according to the amount of received light,
Distance detecting means for detecting the distance to the light irradiation surface of the measured object based on the position signal from the lens position detecting means when the light receiving signal from the displacement measuring light receiving means is maximized,
Tilt measuring imaging means for receiving light reflected on the light irradiation surface of the object to be measured through the objective lens on the imaging surface, and outputting an imaging signal based on the amount of light received on the imaging surface;
An optical measuring device comprising: a tilt detecting unit configured to detect a tilt of a light irradiation surface of the measured object based on the imaging signal from the tilt measuring imaging unit.