JP3967607B2

JP3967607B2 - Height measuring device

Info

Publication number: JP3967607B2
Application number: JP2002045535A
Authority: JP
Inventors: 裕司小野
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-02-22
Filing date: 2002-02-22
Publication date: 2007-08-29
Anticipated expiration: 2022-02-22
Also published as: JP2003247810A

Description

【０００１】
【発明の属する技術分野】
本発明は高さ測定装置に関し、さらに詳しくはレーザ光などのスポット光を測定対象に照射し反射光をＰＳＤなどの光位置検出手段で計測し、三角測量の原理により測定対象の高さを導出する高さ測定装置に関する。
【０００２】
【従来の技術】
従来、立体形状を幾何光学的に測定する方法として、さまざまな光を物体に投影してその反射光を光検出器で測定する方法と、自然光や一般的な照明下で物体を複数の方向からカメラで測定し複数の画像間の相関により立体形状を求める方法との、大きく分けて２つの方法が存在している。そして前者は更に光の投影方法、光検出器の種類、さらにその間の位置関係などにより、さまざまに分類される。
【０００３】
産業機器などによく使われている三角測量法による高さ測定装置の例を図１１（ａ）に示す。
図１１（ａ）において、光源１０１から出た光１０２は測定対象１０３上でスポット光Ｂを形成し、反射光１０４ａは集光レンズ１０５で集光され光位置検出手段１０６、例えばPosition Sensitive Detector（以下、ＰＳＤ素子と称す）上で像Ｂ’を結像する。一方、測定対象１０３が配置されている基板表面におけるスポット光はＡとなり光位置検出手段１０６上の像はＡ’となる。この場合、スポット光Ａとスポット光Ｂとの距離Ｈが基板表面上のある測定対象１０３の高さＨとなり、また、三角測量の原理によれば高さＨは光位置検出手段１０６上の像Ａ’と像Ｂ’との距離ｈに比例する。
【０００４】
ここで、光位置検出手段１０６がＰＳＤ素子の場合、入射光によりＰＳＤ素子から得られる２つの出力信号Ｉａ、Ｉｂと入射光の重心位置ｈとは以下の（式１）に示すとおりの関係を有するため、測定対象１０３の予め設定された基準面からの高さＨは、このようにｈを介して求めることができる。
ｈ＝Ｉａ／（Ｉａ＋Ｉｂ）（式１）
また三角測量の原理に基づいて高さを計測する場合、図１１（ｂ）に示すようにスポット光の近傍に背高部品１０７があると測定できない死角領域が発生するため、集光レンズ１０５ｂ及び光位置検出手段１０６ｂをさらに設け、複数の方向から測定対象を測定し、測定対象の凹凸による死角領域、即ち測定不能領域の低減を図ることもよくある。
【０００５】
【発明が解決しようとする課題】
こうしたＰＳＤ素子を用いて三角測量により測定対象の高さ測定を行う場合、何らかの理由で、スポット光の測定対象１０３上における反射によって直接的に得られる反射光以外の光（以下、迷光と称す）がＰＳＤ素子６に到達した場合、測定高さに誤差が生じる。
【０００６】
図１２（ａ）は、二重反射により測定高さに異常をもたらした例を示す。図において、図１１と同一符号は同一または相当する部分を示している。スポット光の反射光は一般に全方向に進むため、測定対象の近傍に物体１０８がある場合、スポット光に対する反射率や物体１０８の位置や形状によっては、物体１０８の側面で反射した光がＰＳＤ素子１０６に迷光像Ｃ’として達することがある。そのとき図１２（ｂ）に示すようにＰＳＤ素子１０６上の光強度分布はスポット光Ａの反射光による像Ａ’と迷光像Ｃ’とが重なったものとなり、その結果ＰＳＤ素子１０６への入射光の重心位置ｈｅは、像Ａ’の重心位置ｈｔとは異なり、測定高さにｈｔ−ｈｅのような誤差が生じてしまう。
【０００７】
以上は、迷光についてスポット光Ａ近傍の物体による二重反射を例に述べたが、測定対象の凹凸の状態によっては三重反射などの多重反射や、透過物体による内部乱反射、あるいは外乱光によるものなど様々なものがある。
【０００８】
こうした迷光による高さ測定誤差を回避するために、光位置検出手段１０６のＰＳＤ素子に変わるものとしてＣＣＤ素子やフォトダイオードアレイなどの入射光の強度分布も測定できる素子を用いて、入射光のピーク位置を求めるなどの処理を通して、光強度の低い迷光像Ｃ’の影響を除去する方法もある。ただし、この場合、素子の特性としてダイナミックレンジが小さい、かつ応答速度が遅いため、信号処理が複雑になり大規模な処理回路が必要になる、等の問題が生じ、その用途が限られてしまう。
【０００９】
また、それ以外の方法として図１１（ｂ）でも述べたように、一つのスポット光Ａを多方向から同時に計測して、迷光が入射して測定高さに誤差が含まれる方向の測定高さ結果を除いて、誤差を含まない方向の測定高さを採用する方法もある。この場合、複数方向から計測した複数の測定高さから異常な高さを除く方法として、複数の測定高さや測定輝度を比較・演算して誤差の無い高さを求める方法がある。しかし、測定対象の凹凸や表面反射状態が複雑になると、様々な迷光の発生要因があり全ての要因に対して有効な高さ選択方法を取るのが困難となり、特別な形状や反射率・透過率の分布をもつ等の特殊な条件を有する測定対象に関してはどうしても測定高さに異常が発生してしまうという問題があった。
【００１０】
本発明は、上記の問題点に鑑みて創案されたもので、多重反射などによる迷光が混在した場合、迷光の影響を検知測定して、測定対象の測定高さの信頼性情報を提示し、更に測定高さの誤差を改善して測定の精度を向上することのできる高さ測定装置を提供することを目的とする。
【００１１】
【課題を解決するための手段】
本発明の請求項１に記載の高さ測定装置は、スポット光を測定対象に照射する照射手段と、前記スポット光の前記測定対象からの反射光を集光する集光手段と、前記集光手段により集光された反射光を受光し、該反射光の受光位置に対応した電気信号を出力する光位置検出手段と、前記光位置検出手段の出力信号を前記測定対象の高さ情報に変換して出力する高さ情報変換手段と、前記光位置検出手段の近傍に配置された、入射される光の強度を検出して該入射光の強度に対応した信号を出力する複数個の光強度検出手段と、前記複数の光強度検出手段の出力信号のバラツキに基づいて、前記高さ情報変換手段により変換された高さ情報の信頼性を示す情報を計算して出力する信頼性情報取得手段と、を備えたものである。
【００１２】
また、本発明の請求項２に記載の高さ測定装置は、前記高さ測定装置において、前記複数の光強度検出手段は、前記光位置検出手段の周囲に配置されているものである。
【００１６】
また、本発明の請求項３に記載の高さ測定装置は、スポット光を測定対象に照射する照射手段と、前記スポット光の測定対象からの反射光を集光する集光手段と、前記集光手段により集光された反射光を受光し、該反射光の受光位置に対応した電気信号を出力する光位置検出手段と、前記光位置検出手段の近傍に配置された、入射される光の強度を検出して該入射光の強度に対応した信号を出力する複数の光強度検出手段と、前記光位置検出手段の出力信号から、前記複数の光強度検出手段の出力信号から得られる、該光位置検出手段近傍での光強度分布に基づいて、該光位置検出手段に入射した迷光による信号成分を除去し、該迷光による信号成分を除去した前記光位置検出手段の出力信号を前記測定対象の高さ情報に変換する高さ情報変換手段と、を備えたものである。
【００１７】
また、本発明の請求項４に記載の高さ測定装置は、請求項３に記載の高さ測定装置において、前記複数の光強度検出手段は、前記光位置検出手段の光位置検出方向に対して平行に並べて配置されているものである。
【００２１】
【発明の実施の形態】
（実施の形態１）
以下に、本発明の請求項１及び請求項２に記載された発明に対応する高さ測定装置を実施の形態１として、図１、図２、図３を用いて説明する。
【００２２】
図１は、本発明の実施の形態１による高さ測定装置の構成を示すブロック図であり、図において、１は測定用のレーザ光等のスポット状の光を測定対象に照射する光源、５は測定対象から反射光を集光する集光レンズ５、６は集光レンズ５により集光された光を受光して、受光位置に対応した電気信号、即ち測定対象の高さ情報に関する電気信号を出力する光位置検出手段であり、本実施の形態１においては特にＰＳＤ素子を用いている。９は光位置検出手段６の近傍に配置される、入射される光を検知し、その強度を測定する光強度検出手段であり、測定対象から直接的に得られる反射光以外の光を検知するために配置されている。１５は光位置検出手段６の出力信号を測定対象の高さ情報に変換する高さ情報変換手段、１６は光位置検出手段６、光強度検出手段９の出力信号を用いて、高さ情報変換手段１５により得られた高さ情報の信頼性を示す情報である信頼性情報を求め、これを出力する信頼性情報取得手段である。
【００２３】
図２（ａ）は本実施の形態１による高さ測定装置の高さ測定の動作を説明するための断面図であり、図において、図１と同一符号は同一または相当する部分を示しており、光源１は測定用の入射光２を測定対象３に照射する。この入射光２が測定対象３に到達し、その上でスポット光Ａが形成される。４はスポットＡからの反射光、５は反射光４を集光するレンズ（集光手段）、６は測定対象の高さに関する電気信号を出力する光位置検出手段、９は物体８により反射される迷光を検知測定する光強度検出手段である。Ａ’はスポット光Ａが光位置検出手段６において結像した像、Ｃ’は迷光が光位置検出手段６において結像した像である。また、Ｉａ、Ｉｂは光位置検出手段６の出力信号、Ｉｅは光強度検出手段９の出力信号である。
【００２４】
次に、上記のような構成を有する本実施の形態１による高さ測定装置の動作について、図２、図３を参照しながら説明する。
図２（ａ）に示すように、光源１から出た光２は測定対象３上でスポット光Ａを形成し、スポットＡからの反射光４は集光レンズ５により集光され、光位置検出手段６上で像Ａ’として結像する。三角測量の原理によりこの像Ａ’の入射光の光位置検出手段６上での重心位置はスポット光Ａにおける測定対象３の高さＨを表している。
【００２５】
ここで、スポット光Ａの近傍に物体８があり、ある条件下でスポット光Ａでの反射光が物体８の側面で再度反射して、集光レンズ５を経由して光位置検出手段６とその近傍に配置している光強度検出手段９に入射して像Ｃ’とする。
【００２６】
この時、像Ａ’ の入射光と像Ｃ’の入射光とは同時に光位置検出手段６に入射し、光位置検出手段にて複合される。光位置検出手段６がＰＳＤ素子の場合、ＰＳＤ素子６からは、図２（ｂ）に示すように、複合された入射光の重心位置及び光量に応じた２つの信号Ｉａ、Ｉbが出力される。また、光強度検出手段９からは迷光量に応じた信号Ｉｅが出力される。
【００２７】
図２（ｃ）に示すように、高さ情報変換手段はＰＳＤ素子６の２つの出力信号Ｉａ、ＩbからＰＳＤ素子６への入射光の重心位置ｈを求める。ＰＳＤ素子６への入射光がスポット光Ａの反射像Ａ’のみの場合は、この重心位置ｈがスポット光Ａにおける測定対象３の高さＨを表している。
【００２８】
しかし、像Ｃ’のようなノイズになる迷光がＰＳＤ素子６に入射した場合、重心位置ｈは高さＨと等しくなくなる。ＰＳＤ素子６の近傍に配置した光強度検出手段９の出力Ｉｅのレベルが大きい場合は迷光がＰＳＤ素子６にも入射している可能性が高くなり、ＰＳＤ素子６の２つの信号Ｉａ、Ｉbから求まる重心位置ｈとスポット光Ａでの測定対象３の高さＨとの間の差異も大きくなる可能性が高くなる。
【００２９】
これに対し、本実施の形態１に係る高さ測定装置によれば、図２（ｃ）に示すように、信頼性情報取得手段１６はＰＳＤ素子６の出力ＩａとＩｂおよび光強度検出手段９の出力Ｉeを用い、測定高さの信頼性情報Ｅを求めて、この信頼性情報Ｅに基づいて高さ情報変換手段１５から得られる高さ情報が信頼性の高いものであるか否かを判定することができ、精度の低い測定データの使用を未然に防ぐことができる。
【００３０】
具体的な高さ信頼性情報Ｅの求め方としては、光強度検出手段９が１個の場合、例えば以下の（式２）で示すように単純に光強度検出手段９の出力Ｉeと、ＰＳＤ素子６の出力の和Ｂ（Ｂ＝Ｉａ＋Ｉb、入射光量を示す）との比などが考えられる。
Ｅ＝Ｉe／（Ｉａ＋Ｉｂ）（式２）
これは、Ｉａ＋Ｉｂが像Ａ’の光強度つまり信号強度を示していると考え、ノイズ強度Ｉｅを信号強度Ｂで正規化し、像Ａ’の強度に依存しないようにしたことでより汎用性のある高さ信頼性情報を得ることができる。この場合のＥが大きいと測定高さｈの信頼性が低く、Ｅが小さいと測定高さｈの信頼性が高いことになる。
【００３１】
ここで、変形例として、光位置検出手段６の周囲に複数の光強度検出手段を配置した場合について説明する。
【００３２】
図３（ａ）は、光位置検出手段６の周囲に４個の光強度検出手段９ａ、９ｂ、９ｃ、９ｄを配置した場合の光学的な構成を示す断面図である。Ｉｅａ、Ｉｅｂ、Ｉｅｃ、Ｉｅｄはそれぞれ４個光強度検出手段９ａ、９ｂ、９ｃ、９ｄの出力である。
【００３３】
迷光による像Ｃ’が広く広がって光位置検出手段６と４個の光強度検出手段９ａ、９ｂ、９ｃ、９ｄ全体に入射している場合は、図２の説明で述べたように、４個の光強度検出手段９ａ、９ｂ、９ｃ、９ｄの出力合計値Ｉｅａ＋Ｉｅｂ＋Ｉｅｃ＋Ｉｅｄで測定高さｈの信頼性情報Ｅとすることができるが、図３（ｂ）に示すように迷光像Ｃ’が小さく局所的な場合は、一部の光強度検出手段のみ、図の例では光強度検出手段９ａのみに入射することになる。この場合は光強度検出手段９ａの出力Ｉｅａのレベルが大きく、ほかの光強度検出手段９ｂ、９ｃ、９ｄのそれぞれの出力Ｉｅｂ、Ｉｅｃ、Ｉｅｄが小さいため、４個の光強度検出手段９ａ、９ｂ、９ｃ、９ｄの出力のばらつきは迷光像Ｃ’の有無を示すことになる。
【００３４】
つまり、高さ信頼性情報Ｅの求め方としては、光位置検出手段６の近傍に配置した複数の光強度検出手段９の出力Ｉeのバラツキを示す値、例えば最大値と最小値との差や標準偏差等を用いることが考えられる。これにより、局所的な迷光像Ｃ’が入射した場合でも、測定高さｈの信頼性情報は依然として求められ、その効果を発揮することができる。さらに像Ａ’の強度、つまり信号強度を示す光位置検出手段６の出力、即ち光位置検出手段６がＰＳＤ素子の場合はＩa＋Ｉb、とＩeのバラツキとの比をとることにより、像Ａ’の強度に依存しないより汎用性のある高さ信頼性情報を得ることができる。
【００３５】
このように、本実施の形態１による高さ測定装置では、光位置検出手段の近傍に一個もしくは複数個の光強度検出手段と、前記光強度検出手段の出力を用いて測定高さ情報の信頼性情報を求める信頼性情報取得手段とを備えたので、一個の光強度検出手段の出力、または複数個の光強度検出手段の出力の合計値もしくはバラツキを、さらに前記３指標のそれぞれと光位置検出手段の信号強度との比を測定高さの信頼性情報として用いることができ、対象物の高さ計測において迷光の入射による影響を検出し、計測された対象物の高さデータの信頼性を評価して信頼性の低い高さ測定データの使用を未然に防ぐことができる。
【００３６】
なお、本実施の形態１では、光位置検出手段６についてはＰＳＤ素子を例として説明してきたが、ＣＣＤ素子やフォトダイオードアレイなどに置き換えても同様の効果が得られることはいうまでもない。
【００３７】
（実施の形態２）
次に、本発明の請求項６及び請求項９及び請求項１０に記載された発明に対応する高さ測定装置を実施の形態２として、図４、図５、図６を用いて説明する。
図４は、本実施の形態２による高さ測定装置の構成を示すブロック図であり、図において図１と同一符号は同一または相当する部分を示している。なお、本実施の形態２の構成は、信頼性情報取得手段を設けないようにするとともに、光強度検出手段９の出力を高さ情報変換手段１７にも入力するようにし、高さ情報変換手段１７において、光位置検出手段６の出力信号を、光強度検出手段の出力を用いて高さ情報に変換するようにした点においてのみ、前述した実施の形態１の構成と異なるものであり、同一または相当する部分についてのここでの説明を省略する。
【００３８】
図５（ａ）は本実施の形態２による高さ測定装置の高さ測定の動作を説明するための断面図であり、複数の光強度検出手段９を光位置検出手段６の光位置検出が行われる方向（以下、光位置検出方向と称す）上の光位置検出手段６の両側に配置している例を示している。図において、９ａと９ｂは光位置検出手段６の近傍の、測定高さ検出方向の両側に配置されている光強度検出手段である。その他の構成は、前述した実施の形態１において図２（ａ）に示した構成と同様である。
【００３９】
次に、上記のような構成を有する本実施の形態２による高さ測定装置の動作について、図５、図６を参照しながら説明する。
図５（ａ）に示すように、物体８による照射光２の二重反射光は大きく広がり、光位置検出手段であるＰＳＤ素子６と、その近傍にある２つの光強度検出手段９ａ及び９ｂの全体に像Ｃ’として入射している。このときのＰＳＤ素子６と２つの光強度検出手段９ａ及び９ｂの上における、スポット光Ａによる像Ａ’と迷光による像Ｃ’との位置関係を図５（ｂ）に示す。図５（ｃ）には各検出手段の信号出力を示したものである。
【００４０】
このとき、ＰＳＤ素子６の出力Ｉａ、Ｉｂは、像Ａ’と像Ｃ’とが複合した入射光の重心位置と光強度とにより定まる値となる。また光強度検出手段９ａの出力Ｉｅａは迷光像Ｃ’の光強度検出手段９ａへの入射光量に対応する出力、同じく光強度検出手段９ｂの出力Ｉｅｂは迷光像Ｃ’の光強度検出手段９ｂへの入射光量に対応する出力となる。ここで、迷光像Ｃ’の強度分布が３つの検出手段において直線に近いものとすると、ＰＳＤ素子６中における像Ｃ’の光強度分布は台形形状となり、光強度検出手段９ａの出力Ｉｅａと光強度検出手段９ｂの出力ＩｅｂとＰＳＤ素子６のサイズＬとから、この迷光像強度分布の台形形状の各辺の長さを求めることができる。ここで、迷光像Ｃ’によるＰＳＤ素子６の出力分（Ｉａｏ、Ｉｂｏとする）は和（＝Ｉａｏ＋Ｉｂｏ）が台形光強度分布の面積、比（＝Ｉａｏ／（Ｉａｏ＋Ｉｂｏ））が台形強度分布の重心位置となるから、Ｉａｏ及びＩｂｏはＩｅａとＩｅｂとＬから計算により求めることができる。つまり、ＰＳＤ素子６の出力ＩａとＩｂから、Ｉｅａ及びＩｅｂに基づいて求まる迷光像Ｃ’による成分（Ｉａｏ、Ｉｂｏ）を除去した、像Ａ’による成分（Ｉａｔ、Ｉｂｔとする）を用いることにより、高さ情報変換手段１７において測定高さｈを精度良く求めることができる。
以上の関係を数式で述べると以下の（式３）のとおりとなる。
【数１】

係数Ｃａａ、Ｃａｂ、Ｃｂａ、ＣｂｂはＰＳＤ素子６のサイズＬと光強度検出手段９ａ及び９ｂのサイズＬａ及びＬｂから求まる。すなわち、像Ａ’の信号成分Ｉａｔ、Ｉｂｔは、ＰＳＤ素子６の出力Ｉａ、Ｉｂと光強度検出手段９ａ、９ｂの出力Ｉｅａ、Ｉｅｂの１次結合として求めることができる。こうした関係はＰＳＤ素子６や光強度検出手段９ａ、９ｂの面積が異なっても成り立つ。
【００４１】
ここで本実施の形態２に係る高さ測定装置の変形例として、光位置検出手段６の光位置検出方向とは異なる側に配置、即ち複数の光強度検出手段を光位置検出手段６の光位置検出方向に平行に並べて配置した場合について説明する。
図６（ａ）において、ＰＳＤ素子６の光位置検出方向ではない側に５個の光強度検出手段９ａ〜９ｅをＰＳＤ素子６の光位置検出方向に並べている。迷光による像Ｃ’がＰＳＤ素子６と５個の光強度検出手段９ａ〜９ｅの全体に入射し、なお像Ｃ’の光強度分布がＰＳＤ素子６の光位置検出方向の直角方向に変化が少ないとき、図６（ｂ）に示すように５個の光強度検出手段９ａ〜９ｅのそれぞれの出力Ｉｅａ〜Ｉｅｅから、ＰＳＤ素子６中の像Ｃ’の強度分布の近似を求めることができる。すなわち、ＰＳＤ素子６の出力ＩａとＩｂから、Ｉｅａ〜Ｉｅｅに基づいて求まる迷光像Ｃ’による成分Ｉａｏ、Ｉｂｏを除去した像Ａ’による成分Ｉａｔ、Ｉｂｔを用いることにより、高さ情報変換手段１７において測定高さｈを精度良く求めることができる。
【００４２】
以上の関係を数式で述べると以下の（式４）のとおりとなる。
【数２】

ここで係数Ｃａａ〜Ｃａｅ、Ｃｂａ〜ＣｂｅはＰＳＤ素子６のサイズと光強度検出手段９ａ〜９ｅのそれぞれのサイズから求まる。つまり、ＰＳＤ素子６の出力において像Ａ’の信号成分Ｉａｔ、Ｉｂｔは、ＰＳＤ素子６の出力Ｉａ、Ｉｂと光強度検出手段９ａ〜９eの出力Ｉｅａ〜Ｉｅeの１次結合として求めることができる。
【００４３】
なお、以上の図６においては光強度検出手段９の数を５個として述べたが、１個以上のその他の任意の個数としても同様な効果が得られる。また、光強度検出手段９の個数が多いほどＩａｏ、Ｉｂｏを求める精度が良くなり、測定高さの精度を向上することができる。
また、上記説明ではＰＳＤ素子６の片側にのみ光強度検出手段９を配置したが、両側に配置しても同様の効果がある。
【００４４】
このように、本実施の形態２では複数の光強度検出手段を光位置検出手段６の近傍に配置し、光強度検出手段の出力から光位置検出手段６における迷光像の強度分布を推定して、光位置検出手段６の出力を補正することにより、光位置検出手段における対象物の反射光が形成する像に対応する出力を求めて、精度のよい対象物の測定高さに変換することができる。
【００４５】
（実施の形態３）
次に、本発明の請求項７、請求項８に記載された発明に対応する高さ測定装置を実施の形態３として、図７、図８を用いて説明する。
図７は、本実施の形態３による高さ測定装置の構成を示すブロック図であり、図において図１と同一符号は同一または相当する部分を示している。なお、本実施の形態３の構成は、光強度検出手段９の出力を高さ情報変換手段１８にも入力するようにし、この高さ情報変換手段１８により光位置検出手段６の出力を光強度検出手段９の出力を用いて高さ情報に変換するようにした点においてのみ、前述した実施の形態１の構成と異なるものであり、同一または相当する部分についてのここでの説明を省略する。
【００４６】
次に、上記のような構成を有する本実施の形態３による高さ測定装置の動作について、図８を参照しながら説明する。
図８（ａ）は本実施の形態３による高さ測定装置の光位置検出手段及び光強度検出手段における受光像の位置関係の一例を示した図である。
図８（ａ）において、６は光位置検出手段であるＰＳＤ素子、９ａ、９ｂ、９ｃは光強度検出手段である。像Ａ’は、照射光の対象物体において形成したスポット光Ａからの反射光による像、像Ｃ’は迷光による像である。Ｉａ、Ｉｂは光位置検出手段６の出力信号で、Ｉｅａ、Ｉｅｂ及びＩｅｃはそれぞれ光強度検出手段９ａ、９ｂ、９ｃの出力信号である。
【００４７】
図８（ａ）に示すように、ＰＳＤ素子６の周囲に３個の光強度検出手段９ａ、９ｂ、９ｃが配置されており、そこにスポット光Ａの像Ａ’はＰＳＤ素子６上にあり、迷光による像Ｃ’はＰＳＤ素子６と光強度検出手段９ｂ、９ｃに入射している。この場合、図８（ｂ）に示すように迷光像Ｃ’の分布がＰＳＤ素子６の光位置検出方向に直線状分布であっても、光強度検出手段９ａに像Ｃ’は入射していないので、２個の迷光強度検出手段出力ＩｅｂとＩｅｃにより、ＰＳＤ素子６の出力信号Ｉａ、Ｉｂから迷光像Ｃ’成分を除いたＩａｔ、Ｉｂｔを求めることはできない。
【００４８】
そこで、図８（ｃ）に示すように、ＰＳＤ素子６の２つの出力Ｉａ、Ｉｂと３つの光強度検出手段９ａ、９ｂ、９ｃの出力Ｉｅａ、Ｉｅｂ、Ｉｅｃとをそれぞれ２つのグループに出力し、１つのグループでは高さ情報変換手段１８を介して測定高さｈを演算し、もう１つのグループでは信頼性情報取得手段１６を介して高さ信頼性情報Ｅの演算を行う。
【００４９】
こうすることにより、光強度検出手段９により検出された迷光像Ｃ’が測定高さｈの精度向上に寄与できないような光強度分布の場合でも、高さ信頼性情報Ｅを提供することにより信頼性の低い測定高さデータの使用を未然に防ぐことができる。
【００５０】
逆に、図８（ａ）に示した３つの光強度検出手段９ａ、９ｂ、９ｃの出力Ｉｅａ、Ｉｅｂ、Ｉｅｃのバラツキを示す値、例えば最大値と最小値との差が大きい場合、迷光像Ｃ’の分布が偏って分布していると推測することができ、その場合の高さ補正演算をしていても測定高さｈの信頼性が低いことになるのが分かる。
【００５１】
もちろん、図８（ａ）に示した３つの光強度検出手段９ａ、９ｂ、９ｃの出力Ｉｅａ、Ｉｅｂ、Ｉｅｃのバラツキが小さい場合、迷光像Ｃ’が３つの光強度検出手段９ａ、９ｂ、９ｃの全般にわたって入射していることが分かり、３つの出力Ｉｅａ、Ｉｅｂ、Ｉｅｃを高さ情報変換手段に入力させることにより、高さ演算補正をして、精度の高い高さ測定データｈを得ることができる。
【００５２】
このように、本実施の形態３では、光位置検出手段６の周囲に設けられている光強度検出手段９ａ、９ｂ、９ｃの出力を高さ情報変換手段１８、信頼性情報取得手段１６に入力させるようにしたので、光強度検出手段９ａ、９ｂ、９ｃの出力のばらつきが小さいときは、高さ補正計算を通じて精度の良い高さ測定データを得ることができる。また、光強度検出手段９ａ、９ｂ、９ｃの出力のばらつきが大きいときは、信頼性情報を求めて信頼性の低い測定データの使用を未然に防ぐことができる。
【００５３】
（実施の形態４）
次に、本発明の請求項３乃至請求項５に記載された発明に対応する高さ測定装置を実施の形態４として、図９及び図１０を用いて説明する。
図９は、本実施の形態４に係る高さ測定装置の構成を説明するためのブロック図であり、図において、図１と同一符号は同一または相当する部分を示しており、５ａと５ｂは測定対象からの反射光を互いに異なる方向において集光する集光レンズ、６ａ、６ｂは集光レンズ５ａ，５ｂによりそれぞれ集光された光を受光して、受光位置に対応した電気信号、即ち測定対象の高さ情報に関する電気信号を出力する光位置検出手段であり、本実施の形態４においては特にＰＳＤ素子を用いている。１９ａ，１９ｂは光位置検出手段６ａ，６ｂのそれぞれの近傍に配置された、入射される光を検知し、その強度を測定する光強度検出手段であり、測定対象から直接的に得られる反射光以外の光を検知するために配置されている。１５ａ，１５ｂは光位置検出手段６ａ，６ｂの出力信号を測定対象の高さ情報に変換する高さ情報変換手段、１６ａ，１６ｂは光位置検出手段６ａ，６ｂ、光強度検出手段１９ａ，１９ｂの出力信号を用いて、高さ情報変換手段１５ａ，１５ｂにより個別に得られた高さ情報の信頼性を示す情報である信頼性情報を個別に求め、これを出力する信頼性情報取得手段である。また、２０は信頼性情報を用いて各高さ情報変換手段の出力に基づいて測定対象の高さを決定する高さ情報決定手段である。
【００５４】
図１０（ａ）は、本実施の形態４に係る高さ測定装置の動作を説明するための図であり、図において、図２及び図９と同一符号は同一または相当する部分を示しており、４ａと４ｂはスポットＡから互いに異なる方向である光位置検出手段６ａ、６ｂの方向へと進む反射光、像Ａａ’及び像Ａｂ’のそれぞれは集光されたスポット光Ａの反射光が光位置検出手段６ａ、６ｂにおいて形成される像、像Ｃ’はスポット光Ａの物体８における反射光が光位置検出手段６ａにおいて形成される像である。
【００５５】
次に、上記のような構成を有する本実施の形態４による高さ測定装置の動作について、図１０を参照しながら説明する。
光源１より照射光２を測定対象物体３に照射し、物体３においてスポット光Ａが形成されると同時に、スポット光Ａが物体３より反射される。その反射光のうち、２方向の反射光４ａと４ｂがそれぞれ２つの集光レンズ５ａと５ｂを経由して２つの光位置検出手段６ａと６ｂ上で、像Ａａ’と像Ａｂ’として集光される。
【００５６】
高さ情報変換手段１５ａにおいて光位置検出手段６ａの出力信号から像Ａａ’の重心位置ｈａが求まり、また高さ情報変換手段１５ｂにおいて光位置検出手段６ｂの出力信号から像Ａｂ’の重心位置ｈbが求まり、これに基づいて三角測量の原理から、スポット光Ａにおける測定対象３の高さの２つの測定値が求まることになる。
【００５７】
スポット光Ａの反射光のみが２つの光位置検出手段６ａと６ｂに到達した場合は、２つの測定高さｈａとｈｂはともに測定対象３のスポット光Ａにおける高さを表しており、この２つの測定高さｈａとｈｂとを使用し、これらを補正して新たな測定高さｈを求めると、測定誤差は非常に小さなものとなる。例えば、この測定高さｈの補正する方法としては平均値（ｈａ＋ｈｂ）／２を取る方法がある。
【００５８】
しかし、これまでも説明してきたように、スポット光Ａの反射光の一部が近傍の物体８の側面で二重反射し、集光レンズ５ａを経由して光位置検出手段６ａに入射して像Ｃ’となった場合は、２つの測定高さｈａとｈｂのうち、ｈｂは正しいがｈａは正しくなくなる。この場合では測定高さとして、ｈｂをのみ出力すれば誤差は依然として小さなものとなるが、通常２つの測定高さｈａとｈｂのうちどちらが正しいかを判断することは困難である。
【００５９】
そこで、光位置検出手段６ａと６ｂの近傍に光強度検出手段９ａと９ｂを配置して、二重反射などによる迷光像Ｃ’が入射しているかどうかについて、光強度検出手段９ａと９ｂの出力信号から、信頼性情報取得手段１６ａ，１６ｂにより測定高さｈａ及びｈｂのそれぞれについての信頼性情報Ｅａ、Ｅｂを求めて調べる。ｈａとｈｂ、ＥａとＥｂについては前述した各実施の形態でも述べたようにそれぞれ求めることとする。
【００６０】
そして、高さ情報決定手段２０においては、図１０（ｂ）に示すように、２つの測定高さｈａとｈｂから補正により新たな１つの測定高さｈを求める際に、まず、ステップＳ１としてそれぞれの信頼性情報ＥａとＥｂとの両者が信頼性が高いことを示すものであるか否かを判定し、２つとも信頼性が高いことを示す場合には測定高さｈａとｈｂとの両方を使用して測定高さｈを求める。両方の信頼性が高くない場合には、ステップＳ２、及びステップＳ３において、信頼性情報Ｅａ及びＥｂのいずれか一方が、信頼性が高いことを示しているか否か判定し、一方のみが信頼性が高いことを示している場合には、信頼性の高さを示している信頼性情報に対応した測定高さを採用する。そして、信頼性情報Ｅａ、Ｅｂの両者が信頼性が低いことを示す場合には、測定不能とする。
【００６１】
なお、２つの測定高さｈａとｈｂとから測定高さｈの演算方法として、例えば上述した平均値（ｈａ＋ｈｂ）／２を求める方法や、各光位置検出手段６ａ，６ｂの光強度出力を使用して加重平均を求める方法などがある。
【００６２】
このように、本実施の形態４では、２つの光位置検出手段６ａ，６ｂを設け、さらにそれぞれの光位置検出手段６ａ，６ｂの近傍に光強度検出手段１９ａ，１９ｂを設けて、最後に高さ情報決定手段により測定対象の高さを決定するようにしたので、それぞれの光位置検出手段１９ａ，１９ｂにより導出された測定対象の高さ情報から信頼性の低い高さ測定データを除き、信頼性の高い測定データのみを使って、対象物の測定高さを決定することができ、測定対象３の形状や反射率・透過率の分布等の光学的な条件の影響を受けない、精度の良い高さ測定を実現することができる。
【００６３】
なお、本実施の形態４では、測定する方向は例として２方向で述べたが、本発明においては、さらに集光レンズ、光位置検出手段、光強度検出手段、高さ情報変換手段、及び信頼性情報取得手段を備えた構成を異なる方向の反射光を受光できるように一以上追加して設けるようにし、より多くの方向から反射光を同時測定できるようにしてもよく、このような場合においても、上記実施の形態４と同様の効果を奏する。
【００６４】
また、本実施の形態４では、各光位置検出手段の近傍に一個の光強度検出手段を設けたのを例として説明したが、複数個の光強度検出手段にしても同様な効果を得られることができる。
また、本実施の形態４では、高さ情報の変換において光位置検出手段の出力のみを用いて行う例を説明したが、光強度検出手段の出力のバラツキが小さいとき、光強度検出手段の出力をも高さ情報変換手段に入力させて、高さ情報を求めることにしてもよい。この場合、一層精度の高い高さ情報を得られる効果がある。
【００６５】
さらに、前述したいずれの実施の形態においても、迷光像Ｃ’の原因として、スポット光Ａ近傍の物体８における二重反射を例としてあげたが、複数の物体間の３回以上の多重反射や、物体内部への透過による内部反射、また外部の光源による入射などの様々な迷光に対しても、本発明により同様の効果がある。
【００６６】
【発明の効果】
以上のように、本発明の高さ測定装置によれば、スポット光を測定対象に照射する照射手段と、前記スポット光の前記測定対象からの反射光を集光する集光手段と、前記集光手段により集光された反射光を受光し、該反射光の受光位置に対応した電気信号を出力する光位置検出手段と、前記光位置検出手段の出力信号を前記測定対象の高さ情報に変換して出力する高さ情報変換手段と、前記光位置検出手段の近傍に配置された、入射される光の強度を検出して該入射光の強度に対応した信号を出力する複数個の光強度検出手段と、前記複数の光強度検出手段の出力信号のバラツキに基づいて、前記高さ情報変換手段により変換された高さ情報の信頼性を示す情報を計算して出力する信頼性情報取得手段と、を備えようにしたので、二重反射や外乱光などによる迷光が光位置検出手段とその近傍に分布をもって入射した場合、複数の光強度検出手段の間での測定高さ出力のバラツキが大きくなり、それをもって信頼性情報を計算し、光位置検出手段の測定高さ出力に誤差が含まれていることを信頼性情報で示し、精度の低い測定高さデータの使用を未然に防ぐことができるという効果がある。
【００６７】
また、本発明の高さ測定装置によれば、前記高さ測定装置において、前記光強度検出手段を前記光位置検出手段の光位置検出方向の両側に配置するようにしたので、二重反射や外乱光などによる迷光が光位置検出手段とその近傍に分布をもって入射した場合は、このような迷光の発生を上記複数の光強度検出手段からの光検出出力のバラツキによって検知して、迷光により精度の低下した測定高さデータの使用を未然に防ぐことができるという効果がある。
【００７１】
また、本発明の高さ測定装置によれば、スポット光を測定対象に照射する照射手段と、前記スポット光の測定対象からの反射光を集光する集光手段と、前記集光手段により集光された反射光を受光し、該反射光の受光位置に対応した電気信号を出力する光位置検出手段と、前記光位置検出手段の近傍に配置された、入射される光の強度を検出して該入射光の強度に対応した信号を出力する複数の光強度検出手段と、前記光位置検出手段の出力信号から、前記複数の光強度検出手段の出力信号から得られる、該光位置検出手段近傍での光強度分布に基づいて、該光位置検出手段に入射した迷光による信号成分を除去し、該迷光による信号成分を除去した前記光位置検出手段の出力信号を前記測定対象の高さ情報に変換する高さ情報変換手段とを備えるようにしたので、複数の光強度検出手段の出力から光位置検出手段に入射している迷光による誤差量を求めて、光位置検出手段の出力に対して誤差量をキャンセルすることにより迷光の影響を低減した高精度な測定高さを実現することができるという効果がある。
【００７２】
また、本発明の高さ測定装置によれば、前記高さ測定装置において、前記光強度検出手段を前記光位置検出手段の光位置検出方向に対して平行に並べて配置するようにしたので、光位置検出手段の光位置検出方向の迷光分布は直線分布となっていないときでも、光位置検出しない方向の迷光分布が同じである場合、複数の光強度検出手段の出力から光位置検出手段に入射している迷光による誤差量を高精度に求めて、光位置検出手段の出力に対して誤差量をキャンセルすることにより迷光の影響を排除した高精度な測定高さを得ることができるという効果がある。
【図面の簡単な説明】
【図１】本発明の実施の形態１による高さ測定装置の構成を示すブロック図である。
【図２】（ａ）は本実施の形態１による高さ測定装置の高さ測定の様子を説明する一例の光学的な断面図、（ｂ）は光強度分布および各検出手段の出力信号の説明図、（ｃ）は各検出手段の出力信号の関係を示す図である。
【図３】（ａ）は本実施の形態１による高さ測定装置の高さ測定の様子を説明する一例の光学的な断面図、（ｂ）は光位置検出手段、光強度検出手段における受光像の位置関係を示す図である。
【図４】本発明の実施の形態２による高さ測定装置の構成を示すブロック図である。
【図５】（ａ）は本実施の形態２による高さ測定装置の高さ測定の様子を説明する一例の光学的な断面図、（ｂ）は光位置検出手段、光強度検出手段における受光像の位置関係を示す図、（ｃ）は各検出手段の出力信号の関係を示す図である。
【図６】（ａ）は本実施の形態２による高さ測定装置の光位置検出手段、光強度検出手段における受光像の位置関係を示す図、（ｂ）は光強度分布と光強度検出手段の出力信号を説明する図である。
【図７】本発明の実施の形態３による高さ測定装置の構成を示すブロック図である。
【図８】（ａ）は本実施の形態３による高さ測定装置の光位置検出手段、光強度検出手段における受光像の位置関係を示す図、（ｂ）は光強度分布と各検出手段の出力信号を説明する図、（ｃ）は各検出手段の出力信号の関係を示す図である。
【図９】本発明の実施の形態４による高さ測定装置の構成を示すブロック図である。
【図１０】（ａ）は本実施の形態４による高さ測定装置の高さ測定の様子を説明する一例の光学的な断面図、（ｂ）は出力信号の流れと測定高さの出力の関係を示す図である。
【図１１】従来の高さ測定装置を説明する図であり、（ａ）は三角測量による高さ計測原理を示す光学的断面図、（ｂ）は死角の発生と２方向受光を示す光学的な断面図である。
【図１２】迷光による計測高さの誤差発生を説明する図であり、（ａ）は二重反射による計測高さ誤差を光学的な断面図、（ｂ）は迷光の影響を受けたときの光位置検出手段上の光強度分布例を示す図である。
【符号の説明】
１光源
２照射光
３測定対象
４、４ａ、４ｂ反射光
５、５ａ、５ｂ集光レンズ
６、６ａ、６ｂ、光位置検出手段
７障害物
８二重反射を生じるスポット光Ａ近傍の物体
９、９ａ、９ｂ、９ｃ、９ｄ、９ｅ、１９ａ、１９ｂ光強度検出手段
１５、１７、１８、１５ａ、１５ｂ高さ情報変換手段
１６、１６ａ、１６ｂ信頼性情報取得手段
２０高さ情報決定手段
Ａ、Ｂ照射光が測定対象を照射しているスポット光
Ａ’、Ａa’、Ａb’、Ｂ’ スポット光Ａによる光位置検出手段上の像
Ｃ’ 二重反射などの迷光による光位置検出手段上や光強度検出手段上の像
Ｈ測定対象３の高さ
ｈ光位置検出手段が出力する測定した高さ
Ｉａ、Ｉｂ光位置検出手段の出力信号
Ｉｅ、Ｉｅａ、Ｉｅｂ、Ｉｅｃ、Ｉｅｄ、Ｉｅｅ光強度検出手段の出力信号
Ｅ高さ信頼性情報
Ｌ、Ｌａ、Ｌｂ光位置検出手段や光強度検出手段のサイズ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a height measuring apparatus, and more specifically, irradiates a spot light such as a laser beam onto a measurement object, measures reflected light with a light position detection means such as PSD, and derives the height of the measurement object based on the principle of triangulation. The present invention relates to a height measuring device.
[0002]
[Prior art]
Conventionally, three-dimensional shapes are geometrically optically measured by projecting various types of light onto an object and measuring the reflected light with a photodetector, or by measuring an object from multiple directions under natural light or general illumination. There are roughly two methods, that is, a method of obtaining a three-dimensional shape by correlation between a plurality of images measured by a camera. The former is further classified into various types according to the light projection method, the type of photodetector, and the positional relationship therebetween.
[0003]
FIG. 11A shows an example of a height measuring device by triangulation that is often used for industrial equipment.
In FIG. 11A, the light 102 emitted from the light source 101 forms a spot light B on the measurement target 103, and the reflected light 104a is collected by the condenser lens 105, and the light position detecting means 106, for example, Position Sensitive Detector ( Hereinafter, an image B ′ is formed on the PSD element). On the other hand, the spot light on the substrate surface on which the measurement object 103 is arranged is A, and the image on the optical position detection means 106 is A ′. In this case, the distance H between the spot light A and the spot light B is the height H of the measurement object 103 on the substrate surface, and the height H is an image on the optical position detection means 106 according to the principle of triangulation. It is proportional to the distance h between A ′ and the image B ′.
[0004]
Here, when the optical position detection means 106 is a PSD element, the two output signals Ia and Ib obtained from the PSD element by the incident light and the gravity center position h of the incident light have a relationship as shown in the following (Equation 1). Therefore, the height H of the measurement object 103 from the preset reference plane can be obtained through h in this way.
h = Ia / (Ia + Ib) (Formula 1)
Further, when measuring the height based on the principle of triangulation, a blind spot region that cannot be measured is generated if there is a tall component 107 in the vicinity of the spot light as shown in FIG. An optical position detection means 106b is further provided to measure the measurement object from a plurality of directions, and it is often the case that the blind spot area due to the unevenness of the measurement object, that is, the measurement impossible area is reduced.
[0005]
[Problems to be solved by the invention]
When the height of a measurement target is measured by triangulation using such a PSD element, light other than reflected light directly obtained by reflection of the spot light on the measurement target 103 for some reason (hereinafter referred to as stray light). When reaching the PSD element 6, an error occurs in the measurement height.
[0006]
FIG. 12A shows an example in which the measurement height is abnormal due to double reflection. In the figure, the same reference numerals as those in FIG. 11 denote the same or corresponding parts. Since the reflected light of the spot light generally travels in all directions, when the object 108 is in the vicinity of the measurement target, depending on the reflectance with respect to the spot light and the position and shape of the object 108, the light reflected from the side surface of the object 108 is a PSD element. 106 may be reached as a stray light image C ′. At that time, as shown in FIG. 12B, the light intensity distribution on the PSD element 106 is an overlap of the image A ′ and the stray light image C ′ due to the reflected light of the spot light A. As a result, the incident light enters the PSD element 106. The barycentric position he of the light is different from the barycentric position ht of the image A ′, and an error such as ht-he occurs in the measurement height.
[0007]
The double reflection by the object in the vicinity of the spot light A has been described as an example of the stray light. However, depending on the uneven state of the measurement target, the multiple reflection such as the triple reflection, the internal diffuse reflection by the transmission object, the disturbance light, etc. There are various things.
[0008]
In order to avoid such a height measurement error due to stray light, a peak of incident light is obtained by using an element capable of measuring the intensity distribution of incident light, such as a CCD element or a photodiode array, instead of the PSD element of the optical position detecting means 106. There is also a method of removing the influence of the stray light image C ′ having a low light intensity through processing such as obtaining the position. However, in this case, since the dynamic range is small as the characteristics of the element and the response speed is slow, problems such as complicated signal processing and the need for a large-scale processing circuit arise, and its application is limited. .
[0009]
As another method, as described in FIG. 11B, a single spot light A is simultaneously measured from multiple directions, and the measurement height in a direction in which stray light is incident and the measurement height includes an error. There is also a method of adopting the measured height in a direction that does not include an error except for the result. In this case, as a method of removing an abnormal height from a plurality of measurement heights measured from a plurality of directions, there is a method of obtaining a height without error by comparing and calculating a plurality of measurement heights and measurement luminances. However, when the unevenness of the measurement object and the surface reflection state are complicated, there are various stray light generation factors, making it difficult to take an effective height selection method for all the factors. For measurement objects having special conditions such as having a rate distribution, there is a problem that an abnormality occurs in the measurement height.
[0010]
The present invention was devised in view of the above problems, and when stray light due to multiple reflections or the like is mixed, the effect of stray light is detected and measured, and the reliability information of the measurement height of the measurement target is presented. It is another object of the present invention to provide a height measuring apparatus capable of improving measurement accuracy by improving measurement height errors.
[0011]
[Means for Solving the Problems]
The height measuring apparatus according to claim 1 of the present invention includes an irradiation unit that irradiates a measurement target with spot light, a condensing unit that collects reflected light from the measurement target of the spot light, and the condensing Optical position detection means for receiving the reflected light collected by the means and outputting an electrical signal corresponding to the light receiving position of the reflected light, and converting the output signal of the optical position detection means into height information of the measurement object Output height information converting means and a light position detecting means arranged in the vicinity of the light position detecting means for detecting the intensity of incident light and outputting a signal corresponding to the intensity of the incident light. Double Several light intensity detection means, and plural Output signal of light intensity detection means Variation And reliability information acquisition means for calculating and outputting information indicating the reliability of the height information converted by the height information conversion means.
[0012]
Moreover, the height measuring device according to claim 2 of the present invention is the height measuring device, The plurality of light intensity detecting means are arranged around the light position detecting means. Is.
[0016]
Further, the claims of the present invention 3 The height measuring device described in Measure Irradiating means for irradiating a fixed object, condensing means for condensing the reflected light from the spot light measurement object, and the reflected light collected by the condensing means is received, and the reflected light is received at the light receiving position. A light position detecting means for outputting a corresponding electric signal, and a signal corresponding to the intensity of the incident light, which is disposed in the vicinity of the light position detecting means and detects the intensity of the incident light. Output A plurality of light intensity detecting means and an output signal of the light position detecting means From , Output signals of the plurality of light intensity detection means Based on the light intensity distribution in the vicinity of the light position detection means obtained from the above, the signal component due to the stray light incident on the light position detection means is removed, and the output of the light position detection means from which the signal component due to the stray light is removed Signal Height information converting means for converting into height information of the measurement object; With Is.
[0017]
Further, the claims of the present invention 4 The height measuring device according to claim, 3 In the height measuring device according to claim 1, The plurality of light intensity detection means are arranged in parallel to the light position detection direction of the light position detection means. Is.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Hereinafter, a height measuring device corresponding to the first and second aspects of the present invention will be described as a first embodiment with reference to FIGS. 1, 2, and 3.
[0022]
FIG. 1 is a block diagram showing a configuration of a height measuring apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a light source that irradiates a measurement target with spot-like light such as laser light for measurement. Is a condensing lens 5 for condensing the reflected light from the measuring object, and 6 is an electric signal corresponding to the light receiving position, that is, an electric signal related to the height information of the measuring object, by receiving the light collected by the condensing lens 5. In the first embodiment, a PSD element is particularly used. Reference numeral 9 denotes a light intensity detecting means that is disposed in the vicinity of the light position detecting means 6 and detects incident light and measures its intensity, and detects light other than reflected light obtained directly from the measurement object. Is arranged for. Reference numeral 15 denotes a height information converting means for converting the output signal of the light position detecting means 6 into height information of the measurement object. This is reliability information acquisition means for obtaining reliability information which is information indicating the reliability of the height information obtained by the means 15 and outputting it.
[0023]
2A is a cross-sectional view for explaining the height measurement operation of the height measuring apparatus according to the first embodiment. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The light source 1 irradiates the measurement object 3 with the incident light 2 for measurement. The incident light 2 reaches the measuring object 3 and the spot light A is formed thereon. 4 is a reflected light from the spot A, 5 is a lens for condensing the reflected light 4 (condensing means), 6 is an optical position detecting means for outputting an electrical signal relating to the height of the measurement object, and 9 is reflected by the object 8. Light intensity detecting means for detecting and measuring stray light. A ′ is an image in which the spot light A is imaged in the optical position detecting means 6, and C ′ is an image in which stray light is imaged in the optical position detecting means 6. Further, Ia and Ib are output signals of the light position detecting means 6, and Ie is an output signal of the light intensity detecting means 9.
[0024]
Next, the operation of the height measuring apparatus according to the first embodiment having the above-described configuration will be described with reference to FIGS.
As shown in FIG. 2A, the light 2 emitted from the light source 1 forms a spot light A on the measurement object 3, and the reflected light 4 from the spot A is condensed by a condenser lens 5 to detect the optical position. An image is formed on the means 6 as an image A ′. Based on the principle of triangulation, the position of the center of gravity of the incident light of the image A ′ on the light position detecting means 6 represents the height H of the measuring object 3 in the spot light A.
[0025]
Here, there is an object 8 in the vicinity of the spot light A, and the reflected light from the spot light A is reflected again by the side surface of the object 8 under a certain condition. The light is incident on the light intensity detecting means 9 disposed in the vicinity thereof to obtain an image C ′.
[0026]
At this time, the incident light of the image A ′ and the incident light of the image C ′ are simultaneously incident on the optical position detecting means 6 and combined by the optical position detecting means. When the optical position detection means 6 is a PSD element, as shown in FIG. 2B, the PSD element 6 outputs two signals Ia and Ib corresponding to the barycentric position and the amount of light of the combined incident light. . Further, the light intensity detection means 9 outputs a signal Ie corresponding to the stray light amount.
[0027]
As shown in FIG. 2 (c), the height information conversion means obtains the barycentric position h of incident light to the PSD element 6 from the two output signals Ia and Ib of the PSD element 6. When the incident light to the PSD element 6 is only the reflected image A ′ of the spot light A, the barycentric position h represents the height H of the measuring object 3 in the spot light A.
[0028]
However, when stray light that causes noise such as an image C ′ is incident on the PSD element 6, the center-of-gravity position h is not equal to the height H. When the level of the output Ie of the light intensity detecting means 9 arranged in the vicinity of the PSD element 6 is large, there is a high possibility that stray light is incident on the PSD element 6, and from the two signals Ia and Ib of the PSD element 6. There is a high possibility that the difference between the obtained center-of-gravity position h and the height H of the measuring object 3 in the spot light A will also increase.
[0029]
On the other hand, according to the height measuring apparatus according to the first embodiment, FIG. 2 As shown in (c), reliability information acquisition means 16 Is obtained from the height information conversion means 15 based on the reliability information E by using the outputs Ia and Ib of the PSD element 6 and the output Ie of the light intensity detection means 9 to obtain the reliability information E of the measured height. It is possible to determine whether or not the height information is highly reliable, and it is possible to prevent the use of measurement data with low accuracy.
[0030]
As a specific method of obtaining the height reliability information E, when there is one light intensity detecting means 9, for example, as shown in the following (Equation 2), the output Ie of the light intensity detecting means 9 and the PSD are simply calculated. A ratio with the sum B (B = Ia + Ib, indicating the amount of incident light) of the output of the element 6 can be considered.
E = Ie / (Ia + Ib) (Formula 2)
This is more versatile by considering that Ia + Ib represents the light intensity of the image A ′, that is, the signal intensity, and normalizing the noise intensity Ie with the signal intensity B so as not to depend on the intensity of the image A ′. Height reliability information can be obtained. In this case, if E is large, the reliability of the measurement height h is low, and if E is small, the reliability of the measurement height h is high.
[0031]
Here, as a modification, a case where a plurality of light intensity detection means are arranged around the light position detection means 6 will be described.
[0032]
FIG. 3A is a cross-sectional view showing an optical configuration when four light intensity detecting means 9 a, 9 b, 9 c, 9 d are arranged around the light position detecting means 6. Iea, Ieb, Iec, and Ied are the outputs of the four

light intensity detectors

9a, 9b, 9c, and 9d, respectively.
[0033]
When the image C ′ due to stray light spreads widely and is incident on the light position detection means 6 and the four light intensity detection means 9a, 9b, 9c, and 9d as a whole, as described in the explanation of FIG. The output total value Iea + Ieb + Iec + Ied of the light intensity detection means 9a, 9b, 9c, and 9d can be used as the reliability information E of the measurement height h, but the stray light image C ′ is small and locally as shown in FIG. In such a case, only a part of the light intensity detecting means is incident, and in the example shown in the figure, only the light intensity detecting means 9a is incident. In this case, since the level of the output Iea of the light intensity detection means 9a is large and the outputs Ieb, Iec, Ied of the other light intensity detection means 9b, 9c, 9d are small, the four light intensity detection means 9a, 9b , 9c and 9d indicate the presence or absence of the stray light image C ′.
[0034]
That is, as the method of obtaining the height reliability information E, a value indicating the variation in the output Ie of the plurality of light intensity detection means 9 arranged in the vicinity of the light position detection means 6, for example, the difference between the maximum value and the minimum value, It is conceivable to use a standard deviation or the like. Thereby, even when the local stray light image C ′ is incident, the reliability information of the measurement height h is still required, and the effect can be exhibited. Further, the output of the optical position detection means 6 indicating the intensity of the image A ′, that is, the signal intensity, that is, if the optical position detection means 6 is a PSD element, the ratio between Ia + Ib and Ie variation is obtained. More versatile height reliability information that does not depend on strength can be obtained.
[0035]
As described above, in the height measuring apparatus according to the first embodiment, the reliability of the measured height information is obtained by using one or a plurality of light intensity detecting means in the vicinity of the light position detecting means and the output of the light intensity detecting means. Reliability information acquisition means for obtaining sex information, so that the output value of one light intensity detection means, or the total value or variation of the outputs of a plurality of light intensity detection means, and each of the three indices and the light position The ratio to the signal intensity of the detection means can be used as reliability information on the measurement height, and the influence of stray light incident on the height measurement of the object is detected, and the reliability of the measured height data of the object is detected. Can be used to prevent the use of unreliable height measurement data.
[0036]
In the first embodiment, the optical position detection means 6 has been described by taking a PSD element as an example, but it goes without saying that the same effect can be obtained even if it is replaced with a CCD element or a photodiode array.
[0037]
(Embodiment 2)
Next, a height measuring apparatus corresponding to the invention described in

claims

6, 9, and 10 of the present invention will be described as a second embodiment with reference to FIGS. 4, 5, and 6.
FIG. 4 is a block diagram showing the configuration of the height measuring apparatus according to the second embodiment. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In the configuration of the second embodiment, the reliability information acquisition unit is not provided, and the output of the light intensity detection unit 9 is also input to the height information conversion unit 17, so that the height information conversion unit is provided. 17 is different from the configuration of the first embodiment described above only in that the output signal of the light position detection means 6 is converted into height information using the output of the light intensity detection means. Or the description here about a corresponding part is abbreviate | omitted.
[0038]
FIG. 5A is a cross-sectional view for explaining the height measurement operation of the height measurement apparatus according to the second embodiment. The light position detection means 6 detects the light position of the plurality of light intensity detection means 9. An example is shown in which it is arranged on both sides of the light position detection means 6 in the direction in which it is performed (hereinafter referred to as the light position detection direction). In the figure,

reference numerals

9a and 9b denote light intensity detection means arranged on both sides in the measurement height detection direction in the vicinity of the light position detection means 6. Other configurations are the same as those shown in FIG. 2A in the first embodiment.
[0039]
Next, the operation of the height measuring apparatus according to the second embodiment having the above configuration will be described with reference to FIGS.
As shown in FIG. 5 (a), the double reflected light of the irradiation light 2 from the object 8 spreads greatly, and the PSD element 6 as the light position detecting means and the two light

intensity detecting means

9a and 9b in the vicinity thereof. The whole is incident as an image C ′. FIG. 5B shows the positional relationship between the image A ′ by the spot light A and the image C ′ by the stray light on the PSD element 6 and the two light intensity detection means 9a and 9b at this time. FIG. 5C shows the signal output of each detection means.
[0040]
At this time, the outputs Ia and Ib of the PSD element 6 are values determined by the position of the center of gravity of the incident light in which the image A ′ and the image C ′ are combined and the light intensity. The output Iea of the light intensity detection means 9a corresponds to the output corresponding to the amount of light incident on the light intensity detection means 9a of the stray light image C ′, and the output Ieb of the light intensity detection means 9b similarly to the light intensity detection means 9b of the stray light image C ′. The output corresponds to the amount of incident light. Here, if the intensity distribution of the stray light image C ′ is close to a straight line in the three detection means, the light intensity distribution of the image C ′ in the PSD element 6 has a trapezoidal shape, and the output Iea and the light of the light intensity detection means 9a. From the output Ieb of the intensity detector 9b and the size L of the PSD element 6, the length of each side of the trapezoidal shape of this stray light image intensity distribution can be obtained. Here, the sum (= Iao + Ibo) is the area of the trapezoidal light intensity distribution, and the ratio (= Iao / (Iao + Ibo)) is the center of gravity of the trapezoidal intensity distribution for the output (Iao, Ibo) of the PSD element 6 from the stray light image C ′. Since it is the position, Iao and Ibo can be calculated from Iea, Ieb, and L. That is, by using components (Iat and Ibt) obtained by removing the components (Iao and Ibo) due to the stray light image C ′ obtained based on Iea and Ieb from the outputs Ia and Ib of the PSD element 6. In the height information conversion means 17, the measurement height h can be obtained with high accuracy.
The above relationship is expressed by the following formula (Formula 3).
[Expression 1]

The coefficients Caa, Cab, Cba, and Cbb are obtained from the size L of the PSD element 6 and the sizes La and Lb of the light intensity detection means 9a and 9b. That is, the signal components Iat and Ibt of the image A ′ can be obtained as a linear combination of the outputs Ia and Ib of the PSD element 6 and the outputs Iea and Ieb of the

light intensity detectors

9a and 9b. Such a relationship holds even if the areas of the PSD element 6 and the light intensity detection means 9a, 9b are different.
[0041]
Here, as a modification of the height measuring apparatus according to the second embodiment, the light position detecting means 6 is arranged on a side different from the light position detecting direction, that is, a plurality of light intensity detecting means are arranged to be light of the light position detecting means 6. A case in which they are arranged in parallel to the position detection direction will be described.
In FIG. 6A, five light intensity detection means 9 a to 9 e are arranged in the light position detection direction of the PSD element 6 on the side that is not the light position detection direction of the PSD element 6. An image C ′ due to stray light enters the entire PSD element 6 and the five light intensity detection means 9a to 9e, and the light intensity distribution of the image C ′ is little changed in the direction perpendicular to the light position detection direction of the PSD element 6. At this time, as shown in FIG. 6B, an approximation of the intensity distribution of the image C ′ in the PSD element 6 can be obtained from the outputs Iea to Iee of the five light intensity detectors 9a to 9e. That is, by using the components Iat and Ibt obtained by removing the components Iao and Ibo from the stray light image C ′ obtained based on Iea to Iee from the outputs Ia and Ib of the PSD element 6, the height information converting unit 17 is used. The measurement height h can be obtained with high accuracy.
[0042]
The above relationship can be expressed by the following formula (Formula 4).
[Expression 2]

Here, the coefficients Caa to Cae and Cba to Cbe are the size of the PSD element 6 and the light intensity detection means 9a to 9 respectively. e It is obtained from each size. That is, the signal components Iat and Ibt of the image A ′ at the output of the PSD element 6 can be obtained as a linear combination of the outputs Ia and Ib of the PSD element 6 and the outputs Iea to Iee of the light intensity detection means 9a to 9e.
[0043]
In FIG. 6 described above, the number of the light intensity detection means 9 is described as five. However, the same effect can be obtained by using one or more other arbitrary numbers. Further, as the number of the light intensity detecting means 9 increases, the accuracy of obtaining Iao and Ibo is improved, and the accuracy of the measurement height can be improved.
Further, in the above description, the light intensity detecting means 9 is arranged only on one side of the PSD element 6, but the same effect can be obtained if arranged on both sides.
[0044]
As described above, in the second embodiment, a plurality of light intensity detection means are arranged in the vicinity of the light position detection means 6, and the intensity distribution of the stray light image in the light position detection means 6 is estimated from the output of the light intensity detection means. By correcting the output of the optical position detection means 6, an output corresponding to the image formed by the reflected light of the object in the optical position detection means can be obtained and converted to a precise measurement height of the object. it can.
[0045]
(Embodiment 3)
Next, a height measuring apparatus corresponding to the invention described in claims 7 and 8 of the present invention will be described as a third embodiment with reference to FIGS.
FIG. 7 is a block diagram showing the configuration of the height measuring apparatus according to the third embodiment. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In the configuration of the third embodiment, the output of the light intensity detecting means 9 is also input to the height information converting means 18, and the output of the light position detecting means 6 is converted to the light intensity by the height information converting means 18. Only in the point which converted to height information using the output of the detection means 9, it differs from the structure of Embodiment 1 mentioned above, and description here about the part which is the same or it corresponds is abbreviate | omitted.
[0046]
Next, the operation of the height measuring apparatus according to the third embodiment having the above configuration will be described with reference to FIG.
FIG. 8A is a diagram showing an example of the positional relationship of the received light image in the light position detecting means and the light intensity detecting means of the height measuring apparatus according to the third embodiment.
In FIG. 8A, reference numeral 6 denotes a PSD element which is an optical position detection means, and

reference numerals

9a, 9b and 9c denote optical intensity detection means. The image A ′ is an image by reflected light from the spot light A formed on the target object of irradiation light, and the image C ′ is an image by stray light. Ia and Ib are output signals of the optical position detection means 6, and Iea, Ieb and Iec are output signals of the light intensity detection means 9a, 9b and 9c, respectively.
[0047]
As shown in FIG. 8A, three light

intensity detecting means

9a, 9b, 9c are arranged around the PSD element 6, and an image A ′ of the spot light A is on the PSD element 6. The image C ′ due to stray light is incident on the PSD element 6 and the light intensity detection means 9b, 9c. In this case, as shown in FIG. 8B, even if the distribution of the stray light image C ′ is a linear distribution in the light position detection direction of the PSD element 6, the image C ′ is not incident on the light intensity detection means 9a. Therefore, Iat and Ibt obtained by removing the stray light image C ′ component from the output signals Ia and Ib of the PSD element 6 cannot be obtained from the two stray light intensity detection means outputs Ieb and Iec.
[0048]
Therefore, as shown in FIG. 8C, the two outputs Ia and Ib of the PSD element 6 and the outputs Iea, Ieb and Iec of the three light intensity detection means 9a, 9b and 9c are output to two groups, respectively. In one group, the measured height h is calculated via the height information conversion means 18, and in the other group, the height reliability information E is calculated via the reliability information acquisition means 16.
[0049]
In this way, even if the stray light image C ′ detected by the light intensity detecting means 9 has a light intensity distribution that cannot contribute to the improvement of the accuracy of the measurement height h, the reliability can be obtained by providing the height reliability information E. It is possible to prevent the use of low-measurement height data.
[0050]
On the contrary, when the difference between the outputs Iea, Ieb, and Iec of the three

light intensity detectors

9a, 9b, and 9c shown in FIG. 8A, for example, the difference between the maximum value and the minimum value is large, the stray light image It can be inferred that the distribution of C ′ is unevenly distributed, and it can be seen that the reliability of the measured height h is low even if the height correction calculation in that case is performed.
[0051]
Of course, when the variations of the outputs Iea, Ieb, and Iec of the three

light intensity detectors

9a, 9b, and 9c shown in FIG. As a result, the height information is corrected by inputting the three outputs Iea, Ieb, and Iec to the height information conversion means to obtain high-precision height measurement data h. Can do.
[0052]
As described above, in the third embodiment, the output of the light intensity detection means 9a, 9b, 9c provided around the light position detection means 6 is input to the height information conversion means 18 and the reliability information acquisition means 16. Therefore, when the output variations of the light intensity detection means 9a, 9b, 9c are small, accurate height measurement data can be obtained through height correction calculation. Further, when the output variations of the light intensity detection means 9a, 9b, 9c are large, it is possible to obtain reliability information and prevent the use of measurement data with low reliability.
[0053]
(Embodiment 4)
Next, a height measuring device corresponding to the invention described in claims 3 to 5 of the present invention will be described as a fourth embodiment with reference to FIG. 9 and FIG.
FIG. 9 is a block diagram for explaining the configuration of the height measuring apparatus according to the fourth embodiment. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and

reference numerals

5a and 5b denote

Condensing lenses

6a and 6b that collect the reflected light from the measurement object in different directions receive light collected by the condensing

lenses

5a and 5b, respectively, and an electrical signal corresponding to the light receiving position, that is, measurement. This is an optical position detection means for outputting an electrical signal relating to the height information of the object. In the fourth embodiment, a PSD element is used in particular.

Reference numerals

19a and 19b denote light intensity detecting means arranged in the vicinity of the light position detecting means 6a and 6b for detecting incident light and measuring the intensity thereof. Reflected light obtained directly from the measurement object It is arranged to detect other light.

Reference numerals

15a and 15b denote height information conversion means for converting the output signals of the optical position detection means 6a and 6b into height information of the measurement object.

Reference numerals

16a and 16b denote the optical position detection means 6a and 6b and the light intensity detection means 19a and 19b. Reliability information acquisition means for individually obtaining reliability information, which is information indicating the reliability of height information obtained individually by the height information conversion means 15a, 15b, using the output signal, and outputting the reliability information. . Reference numeral 20 denotes height information determination means for determining the height of the measurement object based on the output of each height information conversion means using reliability information.
[0054]
FIG. 10A is a diagram for explaining the operation of the height measuring apparatus according to the fourth embodiment. In the figure, the same reference numerals as those in FIGS. 2 and 9 denote the same or corresponding parts. 4a and 4b are reflected light traveling from the spot A toward the light position detecting means 6a and 6b in different directions, and each of the images Aa ′ and Ab ′ is reflected light of the condensed spot light A. An image formed by the position detection means 6a and 6b, an image C ′, is an image in which the reflected light of the spot light A at the object 8 is formed by the optical position detection means 6a.
[0055]
Next, the operation of the height measuring apparatus according to the fourth embodiment having the above configuration will be described with reference to FIG.
The measurement target object 3 is irradiated with the irradiation light 2 from the light source 1, and the spot light A is formed on the object 3, and at the same time, the spot light A is reflected from the object 3. Of the reflected light, reflected

light

4a and 4b in two directions are condensed as an image Aa ′ and an image Ab ′ on two light position detecting means 6a and 6b via two

condenser lenses

5a and 5b, respectively. Is done.
[0056]
The center of gravity position ha of the image Aa ′ is obtained from the output signal of the light position detecting means 6a in the height information converting means 15a, and the center of gravity position hb of the image Ab ′ from the output signal of the light position detecting means 6b in the height information converting means 15b. Based on this, two measured values of the height of the measuring object 3 in the spot light A are obtained from the principle of triangulation.
[0057]
When only the reflected light of the spot light A reaches the two light position detecting means 6a and 6b, the two measurement heights ha and hb both represent the height of the spot light A of the measuring object 3, and this 2 If two measurement heights ha and hb are used and are corrected to obtain a new measurement height h, the measurement error becomes very small. For example, as a method of correcting the measurement height h, there is a method of taking an average value (ha + hb) / 2.
[0058]
However, as described above, a part of the reflected light of the spot light A is double-reflected on the side surface of the nearby object 8 and enters the light position detecting means 6a via the condenser lens 5a. In the case of the image C ′, of the two measured heights ha and hb, hb is correct but ha is not correct. In this case, if only hb is output as the measurement height, the error is still small, but it is usually difficult to determine which of the two measurement heights ha and hb is correct.
[0059]
Therefore, the light intensity detection means 9a and 9b are arranged in the vicinity of the light position detection means 6a and 6b, and whether the stray light image C ′ due to double reflection or the like is incident is output from the light intensity detection means 9a and 9b. Reliability information Ea and Eb for each of the measurement heights ha and hb is obtained and examined from the signal by the reliability information acquisition means 16a and 16b. Ha and hb, and Ea and Eb are obtained as described in the above embodiments.
[0060]
Then, in the height information determination means 20, as shown in FIG. 10B, when obtaining one new measurement height h by correction from the two measurement heights ha and hb, first, as step S1 It is determined whether or not both pieces of reliability information Ea and Eb indicate high reliability, and when both indicate high reliability, the measured heights ha and hb Both are used to determine the measurement height h. If both the reliability is not high, it is determined in step S2 and step S3 whether one of the reliability information Ea and Eb indicates high reliability, and only one of the reliability information is reliable. In the case where it is shown that the value is high, the measurement height corresponding to the reliability information indicating the high reliability is adopted. If both the reliability information Ea and Eb indicate that the reliability is low, the measurement is impossible.
[0061]
In addition, as a calculation method of the measurement height h from the two measurement heights ha and hb, for example, the above-described method of obtaining the average value (ha + hb) / 2 or the light intensity output of each of the light position detection means 6a and 6b is used. There is a method of obtaining a weighted average.
[0062]
As described above, in the fourth embodiment, the two light position detecting means 6a and 6b are provided, and the light

intensity detecting means

19a and 19b are provided in the vicinity of the light position detecting means 6a and 6b. Since the height of the measurement object is determined by the height information determination means, the height measurement data with low reliability is excluded from the height information of the measurement object derived by the respective light position detection means 19a and 19b. The measurement height of an object can be determined using only highly reliable measurement data, and is not affected by optical conditions such as the shape of the measurement object 3 and the distribution of reflectance and transmittance. Good height measurement can be realized.
[0063]
In the fourth embodiment, the measurement direction is described as two directions as an example. However, in the present invention, a condensing lens, a light position detection means, a light intensity detection means, a height information conversion means, and a reliability are further provided. In such a case, it is possible to add one or more configurations having sex information acquisition means so that reflected light in different directions can be received, and to simultaneously measure reflected light from more directions. Also, the same effects as those of the fourth embodiment are achieved.
[0064]
In the fourth embodiment, an example in which one light intensity detecting unit is provided in the vicinity of each light position detecting unit has been described as an example. However, the same effect can be obtained by using a plurality of light intensity detecting units. be able to.
In the fourth embodiment, an example is described in which height information is converted using only the output of the light position detecting means. However, when the output variation of the light intensity detecting means is small, the output of the light intensity detecting means is small. May be input to the height information converting means to obtain the height information. In this case, there is an effect that height information with higher accuracy can be obtained.
[0065]
Further, in any of the above-described embodiments, as a cause of the stray light image C ′, double reflection in the object 8 in the vicinity of the spot light A is taken as an example. The present invention has the same effect with respect to various stray light such as internal reflection due to transmission into the object and incidence by an external light source.
[0066]
【The invention's effect】
As described above, according to the height measuring apparatus of the present invention, the irradiation unit that irradiates the measurement target with the spot light, the condensing unit that collects the reflected light of the spot light from the measurement target, and the collection unit Light position detection means for receiving reflected light collected by the light means and outputting an electrical signal corresponding to the light receiving position of the reflected light, and using the output signal of the light position detection means as height information of the measurement object A height information converting means for converting and outputting, and an intensity of incident light arranged in the vicinity of the light position detecting means to output a signal corresponding to the intensity of the incident light. Double Several light intensity detection means, and plural Output signal of light intensity detection means Variation And a reliability information acquisition means for calculating and outputting information indicating the reliability of the height information converted by the height information conversion means, such as double reflection and disturbance light Stray light from the light position detection means and its vicinity With distribution If incident, Variation in measurement height output among multiple light intensity detection means increases, and with that, reliability information is calculated, The reliability information indicates that an error is included in the measurement height output of the optical position detection means, and the use of measurement height data with low accuracy can be prevented.
[0067]
Moreover, according to the height measuring device of the present invention, in the height measuring device, Since the light intensity detection means is arranged on both sides of the light position detection direction of the light position detection means, when stray light due to double reflection or disturbance light enters the light position detection means and its vicinity in a distributed manner The occurrence of such stray light is detected by variations in the light detection outputs from the plurality of light intensity detection means, and the accuracy is reduced due to stray light. There is an effect that the use of the measurement height data can be prevented in advance.
[0071]
Further, according to the height measuring apparatus of the present invention, the spot light Measure Irradiating means for irradiating a fixed object, condensing means for condensing the reflected light from the spot light measurement object, and the reflected light collected by the condensing means is received, and the reflected light is received at the light receiving position. A light position detecting means for outputting a corresponding electric signal, and a signal corresponding to the intensity of the incident light, which is disposed in the vicinity of the light position detecting means and detects the intensity of the incident light. Output A plurality of light intensity detecting means and an output signal of the light position detecting means From , Output signals of the plurality of light intensity detection means Based on the light intensity distribution in the vicinity of the light position detection means obtained from the above, the signal component due to the stray light incident on the light position detection means is removed, and the output of the light position detection means from which the signal component due to the stray light is removed Signal Since the height information converting means for converting into the height information of the measurement object is provided, the amount of error due to stray light incident on the light position detecting means is obtained from the outputs of the plurality of light intensity detecting means, and the light By canceling the error amount with respect to the output of the position detection means, there is an effect that it is possible to realize a highly accurate measurement height with reduced influence of stray light.
[0072]
Moreover, according to the height measuring device of the present invention, in the height measuring device, Since the light intensity detecting means is arranged in parallel with the light position detecting direction of the light position detecting means, the stray light distribution in the light position detecting direction of the light position detecting means is not a linear distribution. When the stray light distribution in the direction in which the light position is not detected is the same, the error amount due to the stray light incident on the light position detection means is obtained with high accuracy from the outputs of the plurality of light intensity detection means, and the output of the light position detection means By canceling the amount of error, we obtain a highly accurate measurement height that eliminates the effects of stray light There is an effect that can be.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a height measuring apparatus according to a first embodiment of the present invention.
FIG. 2A is an optical cross-sectional view illustrating an example of the state of height measurement by the height measuring apparatus according to the first embodiment, and FIG. 2B is a diagram illustrating a light intensity distribution and output signals of each detection means. Explanatory drawing, (c) is a figure which shows the relationship of the output signal of each detection means.
FIG. 3A is an optical cross-sectional view of an example for explaining the state of height measurement by the height measuring apparatus according to the first embodiment, and FIG. It is a figure which shows the positional relationship of an image.
FIG. 4 is a block diagram showing a configuration of a height measuring device according to a second embodiment of the present invention.
FIG. 5A is an optical cross-sectional view of an example for explaining the state of height measurement by the height measuring apparatus according to the second embodiment, and FIG. The figure which shows the positional relationship of an image, (c) is a figure which shows the relationship of the output signal of each detection means.
6A is a view showing the positional relationship between received light images in the light position detecting means and the light intensity detecting means of the height measuring device according to the second embodiment, and FIG. 6B is a light intensity distribution and light intensity detecting means. It is a figure explaining the output signal of.
FIG. 7 is a block diagram showing a configuration of a height measuring apparatus according to a third embodiment of the present invention.
FIG. 8A is a diagram showing the positional relationship of the received light image in the light position detecting means and the light intensity detecting means of the height measuring device according to the third embodiment, and FIG. The figure explaining an output signal, (c) is a figure which shows the relationship of the output signal of each detection means.
FIG. 9 is a block diagram showing a configuration of a height measuring apparatus according to a fourth embodiment of the present invention.
10A is an optical cross-sectional view illustrating an example of the state of height measurement performed by the height measuring apparatus according to the fourth embodiment, and FIG. 10B is a diagram illustrating an output signal flow and measurement height output. It is a figure which shows a relationship.
11A and 11B are diagrams for explaining a conventional height measuring device, in which FIG. 11A is an optical cross-sectional view showing the principle of height measurement by triangulation, and FIG. 11B is an optical view showing generation of blind spots and two-way light reception. FIG.
FIGS. 12A and 12B are diagrams for explaining measurement height error generation due to stray light, where FIG. 12A is an optical cross-sectional view of measurement height error due to double reflection, and FIG. It is a figure which shows the example of light intensity distribution on a light position detection means.
[Explanation of symbols]
1 Light source
2 Irradiation light
3 Measurement object
4, 4a, 4b Reflected light
5, 5a, 5b Condensing lens
6, 6a, 6b, optical position detection means
7 obstacles
8 Object near spot light A causing double reflection
9, 9a, 9b, 9c, 9d, 9e, 19a, 19b Light intensity detection means
15, 17, 18, 15a, 15b Height information conversion means
16, 16a, 16b Reliability information acquisition means
20 Height information determination means
A, B Spot light irradiating the object to be measured
A ′, Aa ′, Ab ′, B ′ Images on the light position detecting means by the spot light A
C ′ Image on light position detecting means and light intensity detecting means by stray light such as double reflection
H Height of measurement object 3
h Measured height output by the optical position detector
Ia, Ib Optical position detection means output signal
Ie, Iea, Ieb, Iec, Ied, Iee Output signal of light intensity detection means
E Height reliability information
L, La, Lb Size of light position detection means and light intensity detection means

Claims

Irradiating means for irradiating the measurement object with spot light;
Condensing means for condensing the reflected light from the measurement object of the spot light;
A light position detecting means for receiving the reflected light collected by the light collecting means and outputting an electric signal corresponding to the light receiving position of the reflected light;
Height information conversion means for converting the output signal of the optical position detection means into height information of the measurement object and outputting the information;
It said light position disposed in the vicinity of the detection means, and a double several light intensity detecting means you output a signal corresponding to the intensity of the detected and incident light intensity of incident light,
Reliability information acquisition means for calculating and outputting information indicating the reliability of the height information converted by the height information conversion means based on variations in the output signals of the plurality of light intensity detection means;
A height measuring device comprising:

The height measuring device according to claim 1,
The height measuring device, wherein the plurality of light intensity detecting means are arranged around the light position detecting means .

Irradiating means for irradiating a spot light to the measurement target,
Condensing means for condensing the reflected light from the measurement object of the spot light;
A light position detecting means for receiving the reflected light collected by the light collecting means and outputting an electric signal corresponding to the light receiving position of the reflected light;
A plurality of light intensity detecting means arranged in the vicinity of the light position detecting means for detecting the intensity of incident light and outputting a signal corresponding to the intensity of the incident light;
From an output signal of said light position detecting means, said plurality of obtained from the output signal of the light intensity detecting means, based on the light intensity distribution at the light position detecting means near, the signal due to stray light incident on the light position detecting means Height information converting means for removing the component and converting the output signal of the optical position detecting means from which the signal component due to the stray light has been removed into height information of the measurement object;
A height measuring device comprising:

In the height measuring device according to claim 3 ,
The height measuring device, wherein the plurality of light intensity detecting means are arranged in parallel to the light position detecting direction of the light position detecting means .