JP3749152B2

JP3749152B2 - Lens meter

Info

Publication number: JP3749152B2
Application number: JP2001305618A
Authority: JP
Inventors: 英一柳
Original assignee: Topcon Corp
Current assignee: Topcon Corp
Priority date: 2001-10-01
Filing date: 2001-10-01
Publication date: 2006-02-22
Anticipated expiration: 2021-10-01
Also published as: KR100902972B1; KR20050099475A; CN1410747A; KR20050099476A; KR20030028425A; HK1055329A1; CN1325894C; JP2003106937A

Description

【０００１】
【発明の属する技術分野】
本発明は、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消することのできるレンズメータに関する。
【０００２】
【従来の技術】
従来から、眼鏡レンズの度数を測定するレンズメータには、一般的に２種類の原理のものが知られている。図１はいわゆるＩＯＡ（Infinit on Axis）タイプのレンズメータの光学系を示し、この図１において、１は１個のＬＥＤからなる測定光源、２はコリメータレンズ、３はパターン板、４は受光センサとしてのエリアセンサ、５はレンズ受け、６は測定光路、ＴＬは被検レンズ、Ｏ１は測定光軸である。測定光源１はコリメータレンズ２の光軸Ｏ１上でかつその前側焦点位置に設けられている。コリメータレンズ２は測定光源１からの測定光束を平行光束Ｐ１に変換し、平行光束Ｐ１は光軸Ｏ１に沿って被検レンズＴＬに導かれ、その被検レンズＴＬの凸面側から被検レンズＴＬに入射することとなる。
【０００３】
パターン板３は被検レンズＴＬの後面側（凹面側）に設けられ、そのパターン板３には例えば図２に示すように複数個の円形の開口３ａが形成されている。その開口３ａ間の間隔を２ｈとする。なお、各開口にはマイクロレンズが取り付けられている構成を採用することもでき、開口の形状も円形には限らずスリット状のもの、矩形状の構成を採用することができる。
【０００４】
被検レンズＴＬが測定光路６にセットされていないときには、そのコリメータレンズ２から出射された平行光束Ｐ１がそのままパターン板３に導かれ、平行光束Ｐ１は屈折を受けずにそのパターン板３の開口３ａを通過してエリアセンサ４に導かれる。従って、図３に示すように、エリアセンサ４に投影されたパターン板３の開口投影像３ａ’の間隔２Ｈとパターン板３の開口３ａの間隔２ｈとは等しい。
【０００５】
これに対して、正の度数の被検レンズＴＬを測定光路６にセットすると、平行光束Ｐ１は被検レンズＴＬにより屈折されて収束光となり、開口投影像３ａ’の間隔２Ｈが図４に示すように小さくなる。また、負の度数の被検レンズＴＬを測定光路６にセットすると、平行光束Ｐ１は被検レンズＴＬにより屈折されて発散光となり、開口投影像３ａ’の間隔は広がる。
【０００６】
被検レンズＴＬの裏面頂点位置Ｘ１からパターン板３までの距離Δ、パターン板３からエリアセンサ４までの距離ｄは既知であるので、エリアセンサ４から被検レンズＴＬのバックフォーカス位置Ｘ１’までの距離をｘとすると、
Δｈ＝ｈ−Ｈ
Δｈ／ｄ＝Ｈ／ｘ
であるので、
被検レンズＴＬのバックフォーカスＢＦは、
ＢＦ＝（ｄ／Δｈ）Ｈ＋Δ＋ｄ
によって、求められる。
【０００７】
すなわち、被検レンズＴＬの光学特性の球面度数（Ｓ）、円柱度数（Ｃ）、軸角度（Ａ）をエリアセンサ４上に形成された開口投影像３ａ’の間隔２Ｈを測定し、この測定結果に基づき演算を行って求めることができる。
【０００８】
図５はマニュアル式のレンズメータや一部のオートレンズメータで用いられているいわゆるＦＯＡ（Focus on Axis）と呼ばれるタイプのうち、オートレンズメータの光学系を示している。
【０００９】
その図５において、１０は測定光源部、１１はコリメータレンズ、１２はパターン板としてのターゲット板、１３は投影レンズ、１４は結像レンズ、１５はエリアセンサ、１６はレンズ受け、１７は測定光路である。
【００１０】
測定光源部１０は図６に示すようにここでは４個の測定光源（ＬＥＤ）１０ａ〜１０ｄを有する。各測定光源１０ａ〜１０ｄは測定光軸Ｏ１を境に対称位置に配設されている。そのターゲット板１２には図７に示すように開口１２ａが形成され、開口１２ａの中心は測定光軸Ｏ１に一致されている。ターゲット板１２はその基準位置Ｒ１を起点にして光軸方向に往復動可能とされている。この開口１２ａの形状は円形に限らず、スリット状のもの、矩形状の構成のものでも良い。
【００１１】
コリメータレンズ１１はその前側焦点ｆ１が測定光源１０ａ〜１０ｄの配設位置に一致され、その測定光源１０ａ〜１０ｄの測定光束を平行光束に変換する。そのコリメートレンズ１１の後側焦点ｆ１’はターゲット板１２の基準位置Ｒ１に一致されている。投影レンズ１３は前側焦点位置ｆ２が基準位置Ｒ１に一致され、その後側焦点位置ｆ２’が被検レンズＴＬの裏面頂点位置Ｘ１に一致されている。測定光源１０ａ〜１０ｄと被検レンズＴＬの裏面頂点位置Ｘ１とは共役であり、測定光源１０ａ〜１０ｄの光源像が裏面頂点位置Ｘ１に形成される。
【００１２】
エリアセンサ１５は結像レンズ１４の後側焦点位置ｆに配設され、被検レンズＴＬが測定光路１７にセットされていない状態で、ターゲット板１２とエリアセンサ１５とは、ターゲット板１２が基準位置Ｒ１にあるときに共役である。ターゲット板１２には図７に示すようにその中央に開口１２ａが形成されている。
【００１３】
被検レンズＴＬが測定光路１７にセットされていない場合、基準位置Ｒ１にターゲット板１２があるときにターゲット板１２の開口１２ａを通った測定光束が投影レンズ１３により平行光束Ｐ２とされ、結像レンズ１４により収束されてエリアセンサ１５に結像され、エリアセンサ１５の測定光軸上に開口投影像１２ａ’が形成される。
【００１４】
これに対して、正のパワーを有する被検レンズＴＬを測定光路１７にセットすると、被検レンズＴＬの凹面側から入射されてこの被検レンズＴＬを通過する平行光束Ｐ２が被検レンズＴＬによって収束方向に屈折を受け、ターゲット板１２とエリアセンサ１５との共役関係がずれることになる。
【００１５】
そこで、ターゲット板１２を光軸方向に沿って可動させ、図８に示すように投影レンズ１３によるターゲット板１２のターゲット像１２’を被検レンズＴＬのバックフォーカスＢＦに一致させるようにターゲット板１２を位置させる。
【００１６】
すると、再びターゲット板１２とエリアセンサ１５とが共役となる。よって、ターゲット板１２の基準位置Ｒ１からの移動量に基づき、被検レンズＴＬのバックフォーカスＢＦを以下の式によって求めることができる。
【００１７】
投影レンズ１３の焦点距離をｆ２、ターゲット板１２がエリアセンサ１５と共役になるまでターゲット板１２を測定光軸Ｏ１に沿って移動させたときの基準位置Ｒ１（０ディオプターに相当する位置）からの移動量をＺとすると、被検レンズＴＬの光学特性値（度数）Ｓは、
Ｓ＝Ｚ／ｆ２²
となる。
【００１８】
同様に、円柱度数Ｃ、軸角度Ａを求めることができる。
【００１９】
なお、この図５に示す測定原理タイプのオートレンズメータによる測定については、特開平２−２１６４２８号公報に記載されている。
【００２０】
【発明が解決しようとする課題】
しかしながら、図１に示すように被検レンズＴＬの凸面側から測定光束としての平行光束をその被検レンズＴＬに入射させて被検レンズＴＬの度数を測定するタイプのレンズメータと、被検レンズのＴＬの凹面側から測定光束をその被検レンズＴＬに入射させて、被検レンズＴＬから出射される測定光束が平行光束となるようにターゲット板を移動させるタイプのレンズメータとで、被検レンズＴＬの度数が同一であるといえるのは、被検レンズＴＬの中央部の度数の測定を行う場合であって、図９に示すように、図１に示すタイプのレンズメータでは、被検レンズＴＬの光軸Ｏ２から偏心した位置Ｘ３を測定する場合には、測定光軸Ｏ１に沿って平行に入射した平行光束Ｐ１は被検レンズＴＬにより偏向されて、エリアセンサ４に導かれ、被検レンズＴＬの焦点面Ｆ１上で、測定光軸Ｏ１から偏心位置に結像する。
【００２１】
これに対して、図５に示すタイプのレンズメータでは、被検レンズＴＬの光軸Ｏ２から偏心した位置Ｘ３を測定する場合には、ターゲット板１２とエリアセンサ１５とが共役位置になるようにターゲット板１２を位置させたときに、図１０に示すようにターゲット板１２のターゲット像１２’の開口像１２’ａから出射された測定光束は、被検レンズＴＬによって測定光軸Ｏ１に対して斜めの平行光束Ｐ２’となり、結像レンズ１４によってエリアセンサ１５の中央（測定光軸Ｏ１）から偏心した位置に結像される。
【００２２】
従って、図５に示す測定光束Ｐ２’の進行方向を逆向きにしてかつ図５に示す被検レンズＴＬの凸面側と凹面側とを逆向きにして、図１に示すタイプのレンズメータによる測定光束（実線で示す）Ｐ１と図５に示すタイプのレンズメータによる測定光束（破線で示す）Ｐ２とを重ねて結像状態を示すと図１１に示すようになり、図１に示すタイプのレンズメータにより測定したバックフォーカス値ＢＦと図５に示すタイプのレンズメータにより測定したバックフォーカス値ＢＦ’とが異なることになり、被検レンズＴＬの偏心した位置Ｘ３での度数Ｓを測定すると差異が生じる。しかしながら、レンズメータの測定原理が異なることによって差が生じるのは好ましくないことである。
【００２３】
そこで、図１に示すレンズメータにおいて、被検レンズＴＬの前面に２枚のプリズムを組み合わせたプリズムコンペンセータを配設して、被検レンズＴＬの偏心した位置Ｘ３で図５に示すレンズメータと同一の度数を得られるようにすることが考えられるが、このような構成を採用することにすると、構成が複雑化してコストアップとなるのに加え、被検レンズＴＬから出射する測定光束が測定光軸Ｏ１と一致するまで、プリズムコンペンセータを回転調節する必要があり、その測定が煩雑となりかつ測定に時間がかかることとなる。
【００２４】
本発明は、上記の事情に鑑みて為されたもので、その目的とするところは、被検レンズの凸面側から平行光束を被検レンズに入射させるタイプのものを用いてその被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させるタイプのものを用いてターゲット板の移動量により被検レンズの偏心した位置での度数を測定したときとで、その光学特性値の不一致を簡単な構成で解消することのできるレンズメータを提供することにある。
【００２５】
請求項１に記載のレンズメータは、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消するために、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させる測定原理タイプの光学系が、測定光軸に対して斜めの平行光束を測定光束として被検レンズに入射させる構成とされ、測定光軸に平行な平行光束を被検レンズに入射させることにより得られた被検レンズの偏心した位置での光学特性値と、被検レンズの凸面側から斜めの平行光束を被検レンズに入射させることにより得られた被検レンズの偏心した位置での光学特性値とから、被検レンズの凸面側から測定光束としての平行光束が出射されるようにターゲット板を測定光軸に沿って移動させる測定原理タイプのものを用いての被検レンズの偏心した位置での光学特性値を求めることを特徴とする。
請求項２に記載のレンズメータは、測定光軸に対して斜め方向から入射される平行光束が測定光軸に対して上下左右対称であることを特徴とする。
請求項３に記載のレンズメータは、被検レンズの偏心した位置での測定に用いる平行光束を測定者が選択できることを特徴とする。
請求項４に記載のレンズメータは、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させる測定原理タイプにより得られた被検レンズの偏心した位置での光学特性値を、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて得られた被検レンズの偏心した位置での光学特性値に変換するか否かを、測定者が判断して設定可能であることを特徴とする。
請求項５に記載のレンズメータは、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させる測定原理タイプにより得られた被検レンズの偏心した位置での光学特性値を、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて得られた被検レンズの偏心した位置での光学特性値に換算するか否かを、測定光軸に沿って被検レンズの凸面側から被検レンズに入射する平行光束を用いて自動的に判定し、その判定結果に基づいて換算を行うときに、測定光軸にそって斜め方向から被検レンズの凸面側から被検レンズに入射する平行光束を自動的に選定することを特徴とする。
請求項６に記載のレンズメータは、被検レンズの後方位置に複数の開口を有するパターン板が設けられていることを特徴とする。
請求項７に記載のレンズメータは、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消するために、被検レンズの凸面側から測定光束としての平行光束が出射されるようにターゲット板を移動させる測定原理タイプの光学系のターゲット板に複数個の開口が形成され、被検レンズの偏心した位置での測定に用いる測定光束を測定者が選択できることを特徴とする。
請求項８に記載のレンズメータは、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消するために、被検レンズの凸面側から測定光束としての平行光束が出射されるようにターゲット板を移動させる測定原理タイプの光学系のターゲット板に複数個の開口が形成され、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させる測定原理タイプにより得られた被検レンズの偏心した位置での光学特性値を、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させる測定原理タイプのものを用いて得られた被検レンズの偏心した位置での光学特性値に変換するか否かを、測定者が判断して設定可能であることを特徴とする。
請求項９に記載のレンズメータは、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消するために、被検レンズの凸面側から測定光束としての平行光束が出射されるようにターゲット板を移動させる測定原理タイプの光学系のターゲット板に複数個の開口が形成され、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させる測定原理タイプにより得られた被検レンズの偏心した位置での光学特性値を、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させる測定原理タイプのものを用いて得られた被検レンズの偏心した位置での光学特性値に換算するか否かを、測定光束に基づき自動的に判定することを特徴とする。
請求項１０に記載のレンズメータは、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させる測定原理タイプのレンズメータにおいて、被検レンズの偏心した位置での光学特性値を測定するときに、ターゲット板の測定光軸から外れた開口を通して測定を行うことを特徴とする。
【００３８】
【発明の実施の形態】
以下に、本発明に係わるレンズメータの発明の実施の形態を説明する。
（実施例１）
図１２は被検レンズＴＬの凸面側から平行光束を被検レンズＴＬに入射させてその被検レンズＴＬ透過後の測定光束の変位に基づき被検レンズＴＬの度数を測定するタイプのレンズメータの光学系を示している。
【００３９】
この図１２において、図１に示す光学系と同一構成要素については同一符号を付して説明することとする。
【００４０】
測定光源部１にはここでは図１３に示すように５個のＬＥＤ１ａ〜１ｅが設けられている。ＬＥＤ１ａは測定光軸Ｏ１上に設けられ、ＬＥＤ１ｂ〜１ｅはＬＥＤ１ａに対して上下左右方向に等間隔に設けられている。
【００４１】
各ＬＥＤ１ａ〜１ｅはコリメータレンズ２の焦点面Ｆ１’に設けられている。各ＬＥＤ１ａ〜１ｅから出射された光はコリメータレンズ２によって測定光束としての平行光束に変換される。ＬＥＤ１ａによる測定光束はコリメータレンズ２によって測定光軸Ｏ１に沿った平行光束Ｐ１とされ、ＬＥＤ１ｂ〜１ｅによる平行光束は測定光軸Ｏ１に対して斜めに入射する既知の入射角度を有する平行光束となる。図１２には、ＬＥＤ１ｂによる平行光束が符号Ｐ１’で示され、ＬＥＤ１ｄによる平行光束が符号Ｐ１”で示されている。
【００４２】
被検レンズＴＬは、その被検レンズＴＬの光軸Ｏ２から上下方向に偏心した位置Ｘ３が測定光路６に臨むようにしてレンズ受け５の裏面頂点位置Ｘ１で測定光路６にセットされているものとする。なお、被検レンズＴＬを水平にして測定する場合には前後方向に偏心した位置が測定光路６に臨むようにしてセットされる。
【００４３】
これらの各平行光束Ｐ１、Ｐ１’、Ｐ１”が被検レンズＴＬの偏心した位置Ｘ３に既知の入射角度で入射すると、各平行光束Ｐ１、Ｐ１’、Ｐ１”はその被検レンズＴＬの偏心した位置Ｘ３で異なる偏角を受けると共に、被検レンズＴＬの収差により異なる度数の値が得られることとなる。
【００４４】
そこで、例えば、ＬＥＤ１ｄを点灯させると、このＬＥＤ１ｄに基づく平行光束Ｐ１”が被検レンズＴＬに入射されて、被検レンズＴＬの偏心した位置Ｘ３で屈折を受け、パターン板３の開口３ａを通過した光束によって、エリアセンサ４上に開口投影像３ａ’が形成され、この開口投影像３ａ’を演算回路３０によって演算することにより、光学特性値としてのバックフォーカス値ＢＦ”が得られると共に、射出角θ１が得られる。
【００４５】
すなわち、図２に示すように、４個の開口３ａの中心は測定光軸Ｏ１に一致しているが、被検レンズＴＬの偏心した位置Ｘでの測定を行うと、図４に示すように開口投影像３ａ’が例えば破線で示すようにずれて、４個の開口投影像３ａ’の中心位置Ｗが測定光軸Ｏ１からずれる。この４個の開口投影像３ａ’の中心位置Ｗの測定光軸Ｏ１からの移動量ＷＸとすると、射出角θ１は、パターン板３からエリアセンサ４までの距離が既知であるので、以下の式を用いて演算できる。
【００４６】
θ１＝arctan（ＷＸ／ｄ）
また、プリズム量は射出角に基づき演算できる。
【００４７】
ＬＥＤ１ａを点灯させると、このＬＥＤ１ａに基づく平行光束Ｐ１が被検レンズＴＬの偏心した位置Ｘ３に入射されて、同様にバックフォーカス値ＢＦが得られると共に射出角θ２が得られる。ＬＥＤ１ｂを点灯させると、そのＬＥＤ１ｂに基づく平行光束Ｐ１’に基づき同様にバックフォーカス値ＢＦ’が得られると共に、射出角θ３が得られる。
【００４８】
従って、プリズム量と度数（diopter）との関係をグラフにプロットすると、図１４に示すようになる。その図１４において、横軸はプリズム量（PRISM）を示し、縦軸はバックフォーカス値の逆数（度数）を示しており、Ｑ１は測定光束Ｐ１”に基づき得られた測定点、Ｑ２は測定光束Ｐ１に基づき得られた測定点、Ｑ３は測定光束Ｐ１’に基づき得られた測定点を示している。
【００４９】
これに対して、被検レンズＴＬの凹面側から測定光束を被検レンズＴＬに入射させて被検レンズＴＬの度数を測定するタイプのレンズメータを用いて、被検レンズＴＬの偏心した位置Ｘ３を測定したときのバックフォーカス値は、図１１に示すように、被検レンズＴＬから出射される測定光束の射出角θが０度となるときの値である。
【００５０】
そこで、演算回路３０は得られたプリズム量とバックフォーカス値とに基づき、直線近似を行って直線Ｌを求め、プリズム量が「０」となるときのバックフォーカス値ＢＦ０を求める。このバックフォーカス値ＢＦ０は図１１に示すバックフォーカス値ＢＦ’と理論的に一致する。そのバックフォーカス値ＢＦ０の逆数、すなわち、度数は表示器３１に表示される。
【００５１】
これによって、被検レンズＴＬの凸面側から平行光束を被検レンズＴＬの偏心した位置Ｘ３に入射させて、被検レンズＴＬの偏心した位置Ｘ３での度数を求めるタイプのものであっても、被検レンズＴＬの凹面側から測定光束を入射させ、被検レンズＴＬの凸面側から平行光束を出射させて、被検レンズＴＬの偏心した位置Ｘ３での度数を求めたものと同一の度数を得ることができる。
【００５２】
なお、ここでは、測定光源１ｄ、１ａ、１ｂを同時に点灯させると、エリアセンサ４上での開口投影像３ａ’の区別がつかないので、測定光源１ｄ、１ａ、１ｂを時系列的に点灯させて、エリアセンサ４により検出を行う際の各測定光源による開口投影像３ａ’を区別できるようにした。
【００５３】
ここで、バックフォーカス値とプリズム量とを直線近似してプリズム量が「０」のときの度数を求めることにしたが、多数のＬＥＤ、例えば７個以上のＬＥＤを設けてバックフォーカス値とプリズム量とを求め、曲線近似によってプリズム量が「０」のときの度数を求めることにすれば、その換算精度がより一層向上する。なお、この曲線近似はグラフ上に３点以上測定値をプロットすれば行うことはできる。
【００５４】
この実施例１によれば、複数個の測定光源を順次点灯させてバックフォーカス値を求めた後、換算のための演算を行う構成であるので、１個の測定光源を点灯させて測定を行う構成に較べて測定に時間がかかることになるが、被検レンズＴＬの度数が小さい場合、偏心量（プリズム量）が小さい場合には、被検レンズＴＬの凸面側から平行光束を入射させるタイプのものと、被検レンズＴＬの凹面側から入射させて凸面側から測定光束を平行光束として出射させるタイプのものとで、被検レンズＴＬの偏心した位置Ｘ３での度数にほとんど差はないと考えられるので、被検レンズＴＬの偏心した位置Ｘ３でのバックフォーカス値に所定の閾値を設定して、測定結果がその閾値以下の場合には、１個のＬＥＤのみを点灯させる構成として、他のＬＥＤによる測定は行わない構成とし、その閾値を超えた場合にのみ、他のＬＥＤを点灯させてバックフォーカス量とプリズム量とを求め、換算により被検レンズＴＬの凸面側から測定光束を平行光束として出射させるタイプのもので測定したときに得られるであろう度数を求めることにすれば、操作性を極力犠牲にすることなく、その被検レンズＴＬの偏心した位置Ｘ３での度数を求めることができる。
【００５５】
なお、被検レンズＴＬが累進レンズやバイフォーカルレンズの近用部の測定では、被検レンズＴＬを大きく偏心させて測定させなければならないが、このとき、被検レンズＴＬが凸レンズか凹レンズかによって、偏角方向が逆になるので、測定光束は測定光軸Ｏ１に対称に入射させる構成とするのが望ましい。
【００５６】
また、被検レンズＴＬが累進レンズ、バイフォーカルレンズのとき、その近用部を自動的に認識させて、各ＬＥＤ１ａ〜１ｅを自動的に点灯させて、被検レンズＴＬの凸面側から平行光束を出射させたときの被検レンズＴＬの偏心した位置Ｘ３での度数を求める構成、レンズメータに被検レンズＴＬの近用部を記憶するメモリボタンを設け、測定者がそのボタンを押したときに被検レンズＴＬの凸面側から平行光束を出射させたときの被検レンズＴＬの偏心した位置Ｘ３での度数を求める構成を採用することもできる。
【００５７】
更に、ＬＥＤ１ａを点灯させて測定光軸Ｏ１に沿って平行光束Ｐ１を被検レンズＴＬに入射させ、そのＬＥＤ１ａを点灯させることにより得られた測定結果に基づき、ＬＥＤ１ｂ〜１ｅのいずれを点灯させるか否かを判定し、ＬＥＤ１ａ以外の最小限必要なＬＥＤ１ｂ〜１ｅを点灯させて被検レンズＴＬの偏心した位置Ｘ３での度数を、被検レンズＴＬの凸面側から平行光束を出射させるタイプのものを用いて得られる被検レンズＴＬの偏心した位置Ｘ３での度数に換算する構成とすることもできる。このように構成すれば、測定時間の短縮化を図ることができる。
【００５８】
なお、レンズメータに換算ボタンを設け、被検レンズＴＬの凸面側から平行光束Ｐ１を入射させたときの被検レンズＴＬの偏心した位置Ｘ３での度数（バックフォーカス値ＢＦ）Ｓのみを得たい場合には、この換算ボタンをオフにし、被検レンズＴＬの凸面側から平行光束Ｐ２’を出射させたときの被検レンズＴＬの偏心した位置Ｘ３での度数を得たい場合には、この換算ボタンをオンにする構成を採用することもできる。
（実施例２）
図１５は被検レンズＴＬの凹面側から被検レンズＴＬに向けて測定光束を入射させ、被検レンズＴＬの凸面側から平行光束Ｐ２を出射させるタイプのレンズメータの光学系を示している。この図１５において、図５と同一構成要素については同一符号を付して以下説明する。
【００５９】
ターゲット板１２には図１６に示すように５個の開口１２ａ〜１２ｅが形成されている。開口１２ａは測定光軸Ｏ１上に位置し、その開口１２ａを中心にして等間隔に４個の開口１２ｂ〜１２ｅが形成されている。また、１５’はエリアセンサ１５である。
【００６０】
各ＬＥＤ１０ａ〜１０ｄをそれぞれ点灯させて測定光束をコリメートレンズ１１によりターゲット板１２に導くものとする。また、被検レンズＴＬはその偏心した位置Ｘ３が測定光軸Ｏ１上にあるものとする。
【００６１】
ターゲット板１２は図１５の実線で示す位置にあるときに、その中央の開口１２ａがエリアセンサ１５’と共役にあるものとする。ここで、ＬＥＤ１０ｂ又は１０ｄをそれぞれ別々に点灯させると、図１７（ａ）に示すようにターゲット板１２の５個の開口投影像１２ａ’、１２ｂ’、１２ｄ’、１２ｃ’、１２ｅ’がエリアセンサ１５’上に形成される。被検レンズＴＬは上下方向にのみ偏心され、左右方向には偏心されていないので、ＬＥＤ１０ｂ又は１０ｄを点灯させたときの開口投影像は一致する。
【００６２】
ＬＥＤ１０ａを点灯させると、図１７（ｂ）に示す開口投影像１２ａ’〜１２ｅ’がエリアセンサ１５’上に形成される。左右方向には開口投影像１２ａ’、１２ｃ’、１２ｅ’は一致している。上下方向には開口投影像１２ｂ’、１２ａ’、１２ｄ’はずれている。ここでは、被検レンズＴＬを上下方向にのみ偏心させたものとして測定しているからである。
【００６３】
また、ＬＥＤ１０ｃを点灯させると、図１７（ｃ）に示す開口投影像１２ａ’〜１２ｅ’が形成される。従って、同時にＬＥＤ１０ａ〜１０ｄを点灯させると、エリアセンサ１５’に図１７（ｄ）に示すように開口投影像１２ａ’〜１２ｅ’が形成されることとなる。
【００６４】
ターゲット板１２を測定光軸Ｏ１に沿って可動させて、開口１２ｂがエリアセンサ１５’と共役位置になったとすると、エリアセンサ１５’には、各ＬＥＤ１０ａ〜１０ｄを同時に点灯させたとき、図１７（ｅ）に示す開口投影像が形成される。エリアセンサ１５上には測定光軸Ｏ１から偏心した位置に５個の開口投影像１２ａ’〜１２ｅ’が重なった点が得られる。また、測定光軸Ｏ１上には上下方向に開口投影像１２ｂ’、１２ａ’、１２ｄ’がずれて投影されることになる。
左右の開口投影像１２ｃ’、１２ｅ’は開口投影像１２ａ’に重なる。
【００６５】
従って、ターゲット板１２を移動させたときの移動量の差が被検レンズＴＬの入射角度による度数の差となり、エリアセンサ１５’での開口投影像１２ａ’〜１２ｅ’が一点に重なるようにターゲット板１２を移動させて、各移動位置での度数の差を求めことにより、被検レンズの凸面側から平行光束を入射させるタイプのものを用いて、被検レンズＴＬの偏心した位置で測定を行ったときの度数を換算により求めることができる。
【００６６】
プリズム量はＬＥＤ１０ａ〜１０ｄを同時に点灯させたときに得られる４個の投影像の重心位置と測定光軸Ｏ１との距離として得られる。
【００６７】
この実施例２では、エリアセンサ１５’を用いて４個の投影像の重心位置を求める構成を採用したが、エリアセンサ１５’の代わりにラインセンサを用いることにし、ターゲット板１２の開口として複数のスリットを組み合わせた構成とすることもできる。
（実施例３）
図１８は検影法を利用したレンズメータの光学系を示す図であって、コリメータレンズ２を用いて被検レンズＴＬに平行光束を入射させるもので、被検レンズＴＬが測定光路６にセットされていないときには、集光レンズ４０を用いてＬＥＤ１ａ、１ｂの光源像を回転パターン板４１の回転軸Ｏ３から偏心した位置に形成する。回転パターン板４１には所定の開口パターンが形成され、回転パターン板４１は回転軸Ｏ３を中心にして一定周期で回転されている。
【００６８】
被検レンズＴＬが凸レンズのときには、回転パターン板４１の前側にＬＥＤ１ａ、１ｂのピントの合った光源像が形成され、被検レンズＴＬが凹レンズのときには、回転パターン板４１の後側にＬＥＤ１ａ、１ｂのピントの合った光源像が形成される。その回転パターン板４１とエリアセンサ４との間には結像レンズ４２が配設され、結像レンズ４２の前側焦点は回転パターン板４１に一致され、被検レンズＴＬが測定光路６にセットされていないときには、ＬＥＤ１ａ、１ｂから出射された光束が平行光束としてエリアセンサ４に導かれる。
【００６９】
被検レンズＴＬが測定光路６にセットされていないときには、ピントの合った光源像が回転パターン板４１の配設位置に形成されるので、回転パターン板４１の開口部が光源像を横切るとエリアセンサ４の出力は急激に上昇し、回転パターン板４１の遮光部が光源像を横切ると、エリアセンサ４の出力が急激に減少する。
【００７０】
被検レンズＴＬが測定光路６にセットされているときには、回転パターン板４１の配設位置の前側（被検レンズＴＬが凸レンズのとき）又は後側（被検レンズＴＬが凹レンズのとき）に形成され、回転パターン板４１上では、ＬＥＤ１ａ、１ｂの光源像がボケるため、回転パターン板４１の開口が光源像を横切る際に、エリアセンサ４１の受光出力の増大が緩やかになり、また、回転パターン板４１の遮光部が光源像を横切る際にもエリアセンサ４の受光出力の減少が緩やかになり、被検レンズＴＬの度数が大きければ大きいほど、回転パターン板４１の配設位置から前側ピント位置又は後側ピント位置までのズレ量が大きくなるので、かつ、被検レンズＴＬの収差が大きければ多いほどそのズレ量が大きくなるので、回転パターン板４１上でのＬＥＤ１ａ、１ｂの光源像のボケ量が大きくなる。
【００７１】
従って、エリアセンサ４の受光出力の増減の傾向の度合い、増減の現れ方によって被検レンズＴＬの偏心した位置Ｘ３での度数、プリズム量を求めることができ、ＬＥＤ１ａ、１ｂを順次点灯して、各ＬＥＤ１ａ、１ｂによる度数、プリズム量を求めれば、図１４に示すと同様の測定結果を得ることができる。
【００７２】
なお、この検影法によるレンズメータの測定の詳細は特開２０００−２６６６３９号に記載されている。
【００７３】
【発明の効果】
本発明によれば、被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消することができる。
【図面の簡単な説明】
【図１】被検レンズの凸面側から平行光束を入射させて被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求めるタイプのレンズメータの光学系を示す模式図である。
【図２】図１に示すパターン板の平面図である。
【図３】図１に示す光学系の測定光路に被検レンズがセットされていないときにエリアセンサセンサに形成される開口投影像を示す説明図である。
【図４】図１に示す光学系の測定光路に正のパワーを有する被検レンズがセットされているときにエリアセンサに形成される開口投影像の説明図である。
【図５】ターゲット板を測定光軸に沿って可動させかつ被検レンズの凸面側から平行光束が出射されるようにしてターゲット板の移動量により被検レンズの光学特性を求めるタイプのレンズメータの光学系を示す模式図である。
【図６】図５に示す測定光源の配置構成を説明するための平面図である。
【図７】図５に示すターゲット板の平面図である。
【図８】図８は図５に示す測定原理タイプのレンズメータの測定光路に被検レンズをセットして、被検レンズの凸面側から平行光束が出射されるようにターゲット板を測定光路に沿って可動させた状態を説明するための模式図である。
【図９】図１に示す測定原理タイプのレンズメータの測定光路に被検レンズの偏心した位置を臨ませて測定したときに得られるバックフォーカス値を説明するための模式図である。
【図１０】図５に示す測定原理タイプのレンズメータの測定光路に被検レンズの偏心した位置を臨ませて測定したときに得られるバックフォーカス値を説明するための模式図である。
【図１１】図１に示す測定原理タイプのレンズメータを用いて測定したときに得られる被検レンズの偏心した位置でのバックフォーカス値と図５に示す測定原理タイプのレンズメータを用いて測定したときに得られる被検レンズの偏心した位置でのバックフォーカス値との差異を説明するために両者を重ね合わせて描いた模式図である。
【図１２】被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消するために、複数個の測定光源を図１に示す測定原理タイプの光学系に設けたことを説明するための説明図である。
【図１３】図１２に示す複数個の測定光源の配設状態を示す説明図である。
【図１４】図１２に示すレンズメータの光学系を用いて被検レンズの偏心した位置を測定したときに得られる測定結果をプロットしたグラフ図である。
【図１５】被検レンズの凸面側から測定光束としての平行光束を被検レンズに入射させかつ被検レンズ透過後の測定光束の変位により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときと、被検レンズの凹面側から測定光束を被検レンズに入射させかつ凸面側から平行光束が出射されるようにターゲット板を測定光軸に沿って移動させたときのターゲット板の移動量により被検レンズの光学特性を求める測定原理タイプのものを用いて被検レンズの偏心した位置での光学特性を測定したときとで、その光学特性の不一致を解消するために、複数個の開口を有するターゲット板を光学系に設けた状態を示す説明図である。
【図１６】図１５に示すターゲット板の平面図である。
【図１７】ターゲット板を通過した光束に基づきエリアセンサ上に形成される開口投影像を説明するための模式図である。
【図１８】検影法によるレンズメータの説明図である。
【符号の説明】
Ｏ１…測定光軸
ＴＬ…被検レンズ
Ｘ３…偏心した位置
Ｐ１、Ｐ１’、Ｐ１”…平行光束[0001]
BACKGROUND OF THE INVENTION
The present invention is a measurement principle type in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens and the optical characteristics of the test lens are obtained by displacement of the measurement light beam after passing through the test lens. When measuring the optical characteristics at the eccentric position of the test lens, the target plate is placed so that the measurement light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. When measuring the optical characteristics at the decentered position of the test lens using a measurement principle type that obtains the optical characteristics of the test lens based on the amount of movement of the target plate when moved along the measurement optical axis. The present invention also relates to a lens meter capable of eliminating the mismatch of the optical characteristics.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there are generally known two types of lens meters for measuring the power of eyeglass lenses. FIG. 1 shows an optical system of a so-called IOA (Infinit on Axis) type lens meter. In FIG. 1, 1 is a measurement light source composed of one LED, 2 is a collimator lens, 3 is a pattern plate, and 4 is a light receiving sensor. , 5 is a lens receiver, 6 is a measurement optical path, TL is a lens to be measured, and O1 is a measurement optical axis. The measurement light source 1 is provided on the optical axis O1 of the collimator lens 2 and at the front focal position thereof. The collimator lens 2 converts the measurement light beam from the measurement light source 1 into a parallel light beam P1, and the parallel light beam P1 is guided to the test lens TL along the optical axis O1, and the test lens TL from the convex surface side of the test lens TL. It will enter into.
[0003]
The pattern plate 3 is provided on the rear surface side (concave surface side) of the test lens TL, and a plurality of circular openings 3a are formed in the pattern plate 3 as shown in FIG. The interval between the openings 3a is 2h. In addition, the structure by which the micro lens is attached to each opening can also be employ | adopted, and the shape of an opening is not restricted circular, A slit-shaped thing and a rectangular-shaped structure can be employ | adopted.
[0004]
When the test lens TL is not set in the measurement optical path 6, the parallel light beam P1 emitted from the collimator lens 2 is directly guided to the pattern plate 3, and the parallel light beam P1 is not refracted and is opened in the pattern plate 3. It passes through 3a and is guided to the area sensor 4. Therefore, as shown in FIG. 3, the interval 2H of the opening projection image 3a ′ of the pattern plate 3 projected onto the area sensor 4 and the interval 2h of the opening 3a of the pattern plate 3 are equal.
[0005]
On the other hand, when the test lens TL having a positive power is set in the measurement optical path 6, the parallel light beam P1 is refracted by the test lens TL to become convergent light, and the interval 2H between the aperture projection images 3a ′ is shown in FIG. It becomes so small. When the test lens TL having a negative power is set in the measurement optical path 6, the parallel light beam P1 is refracted by the test lens TL to become divergent light, and the interval between the aperture projection images 3a 'is widened.
[0006]
Since the distance Δ from the back surface vertex position X1 of the test lens TL to the pattern plate 3 and the distance d from the pattern plate 3 to the area sensor 4 are known, from the area sensor 4 to the back focus position X1 ′ of the test lens TL. If the distance of x is x,
Δh = h−H
Δh / d = H / x
So
The back focus BF of the test lens TL is
BF = (d / Δh) H + Δ + d
Is required.
[0007]
In other words, the spherical power (S), cylindrical power (C), and axial angle (A) of the optical characteristics of the lens TL to be measured are measured for the interval 2H of the aperture projection image 3a ′ formed on the area sensor 4, and this measurement is performed. The calculation can be performed based on the result.
[0008]
FIG. 5 shows an optical system of an auto lens meter among the so-called FOA (Focus on Axis) type used in a manual type lens meter and some auto lens meters.
[0009]
In FIG. 5, 10 is a measurement light source unit, 11 is a collimator lens, 12 is a target plate as a pattern plate, 13 is a projection lens, 14 is an imaging lens, 15 is an area sensor, 16 is a lens receiver, and 17 is a measurement optical path. It is.
[0010]
As shown in FIG. 6, the measurement light source unit 10 includes four measurement light sources (LEDs) 10 a to 10 d here. Each of the measurement light sources 10a to 10d is disposed at a symmetrical position with respect to the measurement optical axis O1. The target plate 12 has an opening 12a as shown in FIG. 7, and the center of the opening 12a coincides with the measurement optical axis O1. The target plate 12 can reciprocate in the optical axis direction starting from the reference position R1. The shape of the opening 12a is not limited to a circle, but may be a slit shape or a rectangular configuration.
[0011]
The collimator lens 11 has its front focal point f1 aligned with the position where the measurement light sources 10a to 10d are disposed, and converts the measurement light beam of the measurement light sources 10a to 10d into a parallel light beam. The rear focal point f1 'of the collimating lens 11 is coincident with the reference position R1 of the target plate 12. In the projection lens 13, the front focal position f2 is coincident with the reference position R1, and the rear focal position f2 'is coincident with the back surface vertex position X1 of the lens TL to be measured. The measurement light sources 10a to 10d and the back surface vertex position X1 of the test lens TL are conjugate, and the light source images of the measurement light sources 10a to 10d are formed at the back surface vertex position X1.
[0012]
The area sensor 15 is disposed at the rear focal position f of the imaging lens 14, and the target plate 12 and the area sensor 15 are the reference plate 12 as a reference in a state where the test lens TL is not set in the measurement optical path 17. Conjugate when in position R1. As shown in FIG. 7, the target plate 12 has an opening 12a at the center thereof.
[0013]
When the test lens TL is not set in the measurement optical path 17, when the target plate 12 is at the reference position R1, the measurement light beam that has passed through the opening 12a of the target plate 12 is converted into a parallel light beam P2 by the projection lens 13, and image formation is performed. The light is converged by the lens 14 and imaged on the area sensor 15, and an aperture projection image 12 a ′ is formed on the measurement optical axis of the area sensor 15.
[0014]
On the other hand, when the test lens TL having a positive power is set in the measurement optical path 17, the parallel light beam P2 incident from the concave surface side of the test lens TL and passing through the test lens TL is caused by the test lens TL. Due to refraction in the convergence direction, the conjugate relationship between the target plate 12 and the area sensor 15 is shifted.
[0015]
Therefore, the target plate 12 is moved along the optical axis direction, and the target plate 12 so that the target image 12 ′ of the target plate 12 by the projection lens 13 coincides with the back focus BF of the test lens TL as shown in FIG. Position.
[0016]
Then, the target plate 12 and the area sensor 15 are conjugate again. Therefore, based on the amount of movement of the target plate 12 from the reference position R1, the back focus BF of the test lens TL can be obtained by the following equation.
[0017]
From the reference position R1 (position corresponding to 0 diopter) when the focal length of the projection lens 13 is f2, and the target plate 12 is moved along the measurement optical axis O1 until the target plate 12 is conjugate with the area sensor 15. When the movement amount is Z, the optical characteristic value (frequency) S of the lens TL to be measured is
S = Z / f2²
It becomes.
[0018]
Similarly, the cylindrical power C and the shaft angle A can be obtained.
[0019]
Note that the measurement by the measurement principle type auto lens meter shown in FIG. 5 is described in JP-A-2-216428.
[0020]
[Problems to be solved by the invention]
However, as shown in FIG. 1, a lens meter of a type that measures the power of the test lens TL by allowing a parallel light beam as a measurement light beam to enter the test lens TL from the convex surface side of the test lens TL, and the test lens A lens meter of a type in which a measurement light beam is incident on the lens TL from the concave surface side of the TL and the target plate is moved so that the measurement light beam emitted from the test lens TL becomes a parallel light beam. It can be said that the power of the lens TL is the same when measuring the power of the central portion of the lens TL. As shown in FIG. 9, the lens meter of the type shown in FIG. When measuring the position X3 decentered from the optical axis O2 of the lens TL, the parallel light flux P1 incident in parallel along the measurement optical axis O1 is deflected by the lens TL to be tested and guided to the area sensor 4, On the focal plane F1 of the sample lens TL, it focused on the eccentric position from the measurement optical axis O1.
[0021]
On the other hand, in the type of lens meter shown in FIG. 5, when measuring the position X3 decentered from the optical axis O2 of the lens TL to be measured, the target plate 12 and the area sensor 15 are in a conjugate position. When the target plate 12 is positioned, as shown in FIG. 10, the measurement light beam emitted from the aperture image 12′a of the target image 12 ′ of the target plate 12 is measured with respect to the measurement optical axis O1 by the test lens TL. An oblique parallel light beam P2 ′ is formed and is imaged by the imaging lens 14 at a position decentered from the center of the area sensor 15 (measurement optical axis O1).
[0022]
Accordingly, the measurement light beam P2 ′ shown in FIG. 5 is reversed in the traveling direction and the convex surface side and the concave surface side of the lens TL shown in FIG. When the light beam P1 (shown by a solid line) P1 and a measurement light beam P2 (shown by a broken line) P2 measured by a lens meter of the type shown in FIG. The back focus value BF measured by the meter is different from the back focus value BF ′ measured by the type of lens meter shown in FIG. 5, and the difference is found when the power S at the eccentric position X3 of the lens TL to be measured is measured. Arise. However, it is not preferable that the difference is caused by different measurement principles of the lens meter.
[0023]
Therefore, in the lens meter shown in FIG. 1, a prism compensator combining two prisms is arranged on the front surface of the test lens TL, and the same as the lens meter shown in FIG. 5 at the eccentric position X3 of the test lens TL. However, if such a configuration is adopted, the configuration becomes complicated and the cost is increased, and the measurement light beam emitted from the lens TL to be measured is measured light. It is necessary to rotate and adjust the prism compensator until it coincides with the axis O1, which makes the measurement complicated and takes time.
[0024]
The present invention has been made in view of the above circumstances, and an object of the present invention is to use a type in which a parallel light beam is incident on the test lens from the convex surface side of the test lens. When measuring the optical characteristics at the decentered position, and using a type in which the measurement light beam is incident on the test lens from the concave side of the test lens, the test lens is decentered by the amount of movement of the target plate. It is an object of the present invention to provide a lens meter that can eliminate the discrepancy in optical characteristic values with a simple configuration when the frequency is measured.
[0025]
  The lens meter according to claim 1 obtains optical characteristics of the test lens by causing a parallel light beam as a measurement light beam to enter the test lens from the convex surface side of the test lens and displacing the measurement light beam after passing through the test lens. When measuring the optical characteristics at the eccentric position of the test lens using the measurement principle type, the measurement light beam is incident on the test lens from the concave surface side of the test lens, and the parallel light beam is emitted from the convex surface side Optical characteristics at the eccentric position of the test lens using a measurement principle type lens that obtains the optical characteristics of the test lens from the amount of movement of the target plate when the target plate is moved along the measurement optical axis In order to eliminate the discrepancy between the optical characteristics of the measurement lens, the measurement principle type optical system in which a parallel light beam as the measurement light beam is incident on the test lens from the convex surface side of the test lens is measured. To be incident on the sample lens a parallel beam obliquely as measuring beam with respect to the axisThe optical characteristic value at the decentered position of the test lens obtained by making a parallel light beam parallel to the measurement optical axis incident on the test lens, and the oblique parallel light beam from the convex surface side of the test lens. From the optical characteristic value at the decentered position of the test lens obtained by making it enter the test lens, the target plate is irradiated with the measurement light so that a parallel light beam as a measurement light beam is emitted from the convex surface side of the test lens. It is characterized in that an optical characteristic value at an eccentric position of a lens to be measured is obtained using a measurement principle type that moves along an axis..
  The lens meter according to claim 2 is characterized in that the parallel light flux incident from an oblique direction with respect to the measurement optical axis is vertically and horizontally symmetrical with respect to the measurement optical axis.
The lens meter according to claim 3 is characterized in that a measurer can select a parallel light beam used for measurement at an eccentric position of the lens to be examined.
The lens meter according to claim 4 is an optical characteristic value at an eccentric position of the test lens obtained by a measurement principle type in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens. The target plate is moved according to the amount of movement of the target plate when the target plate is moved along the measurement optical axis so that the measurement light beam enters the test lens from the concave surface side and the parallel light beam is emitted from the convex surface side. It is possible for the measurer to judge and set whether or not to convert to the optical characteristic value at the eccentric position of the test lens obtained by using the measurement principle type that calculates the optical characteristics of the test lens. Features.
The lens meter according to claim 5 is an optical characteristic value at an eccentric position of the test lens obtained by a measurement principle type in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens. The target plate is moved according to the amount of movement of the target plate when the target plate is moved along the measurement optical axis so that the measurement light beam enters the test lens from the concave surface side and the parallel light beam is emitted from the convex surface side. Convex side of the test lens along the measurement optical axis to determine whether or not to convert to the optical property value at the eccentric position of the test lens obtained using the measurement principle type to obtain the optical characteristics of the test lens Is automatically determined using a parallel light beam incident on the lens to be tested, and when conversion is performed based on the determination result, the lens is projected from the convex side of the lens to be tested from an oblique direction along the measurement optical axis. Incident parallel light flux Automatically wherein the selecting.
The lens meter according to claim 6 is characterized in that a pattern plate having a plurality of openings is provided at a rear position of the lens to be examined.
According to a seventh aspect of the present invention, a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens, and an optical characteristic of the test lens is obtained by displacement of the measurement light beam after passing through the test lens. When measuring the optical characteristics at the eccentric position of the test lens using the measurement principle type, the measurement light beam is incident on the test lens from the concave surface side of the test lens, and the parallel light beam is emitted from the convex surface side Optical characteristics at the eccentric position of the test lens using a measurement principle type lens that obtains the optical characteristics of the test lens from the amount of movement of the target plate when the target plate is moved along the measurement optical axis In order to eliminate the discrepancy in the optical characteristics when measuring the measurement principle, the target plate is moved so that a parallel beam as a measurement beam is emitted from the convex surface side of the lens to be measured. A plurality of openings are formed in the target plate of the optical system, characterized in that the measuring beam can be selected is measurer used for measurement at a position eccentric of the lens.
The lens meter according to claim 8 is a parallel light beam as a measurement light beam from a convex surface side of a test lens. When the optical characteristics at the decentered position of the test lens are measured using a measuring principle type lens that obtains the optical characteristics of the test lens by the displacement of the measurement light beam after passing through the test lens. And the amount of movement of the target plate when the target plate is moved along the measurement optical axis so that the measurement light beam enters the test lens from the concave surface side and the parallel light beam is emitted from the convex surface side. In order to eliminate the discrepancy between the optical characteristics when measuring the optical characteristics at the decentered position of the test lens using a measurement principle type lens that calculates the optical characteristics of the test lens, the convex surface of the test lens A plurality of apertures are formed in the target plate of the measurement principle type optical system that moves the target plate so that a parallel light beam as a measurement light beam is emitted from the side, and the measurement light from the concave surface side of the test lens The optical characteristic value at the decentered position of the test lens obtained by the measurement principle type in which the target plate is moved along the measurement optical axis so that a parallel light beam is emitted from the convex surface side. Whether or not to convert to an optical characteristic value at an eccentric position of the test lens obtained by using a measurement principle type in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens This is characterized in that the measurer can judge and set the value.
The lens meter according to claim 9 obtains the optical characteristics of the test lens by causing a parallel light beam as a measurement light beam to enter the test lens from the convex surface side of the test lens and displacing the measurement light beam after passing through the test lens. When measuring the optical characteristics at the eccentric position of the test lens using the measurement principle type, the measurement light beam is incident on the test lens from the concave surface side of the test lens, and the parallel light beam is emitted from the convex surface side Optical characteristics at the eccentric position of the test lens using a measurement principle type lens that obtains the optical characteristics of the test lens from the amount of movement of the target plate when the target plate is moved along the measurement optical axis In order to eliminate the discrepancy in the optical characteristics when measuring the measurement principle, the target plate is moved so that a parallel beam as a measurement beam is emitted from the convex surface side of the lens to be measured. A plurality of apertures are formed in the target plate of the optical system, and the target plate is used as the measurement optical axis so that the measurement light beam is incident on the test lens from the concave surface side and the parallel light beam is emitted from the convex surface side. Measurement principle type that allows the optical characteristic value at the decentered position of the test lens obtained by the measurement principle type to be moved along to the test lens to be incident on the test lens from the convex surface side of the test lens. Whether to convert to an optical characteristic value at a decentered position of the lens to be obtained obtained by using is automatically determined based on the measured light flux.
The lens meter according to claim 10 is a measurement that moves the target plate along the measurement optical axis so that the measurement light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. In the principle type lens meter, when measuring the optical characteristic value at the eccentric position of the lens to be measured, the measurement is performed through an opening off the measurement optical axis of the target plate.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the lens meter according to the present invention will be described below.
(Example 1)
FIG. 12 shows a lens meter of a type in which a parallel light beam is incident on the test lens TL from the convex surface side of the test lens TL and the power of the test lens TL is measured based on the displacement of the measurement light beam after passing through the test lens TL. The optical system is shown.
[0039]
In FIG. 12, the same components as those in the optical system shown in FIG.
[0040]
Here, the measurement light source unit 1 is provided with five LEDs 1a to 1e as shown in FIG. The LED 1a is provided on the measurement optical axis O1, and the LEDs 1b to 1e are provided at equal intervals in the vertical and horizontal directions with respect to the LED 1a.
[0041]
  Each LED 1 a to 1 e is provided on the focal plane F <b> 1 ′ of the collimator lens 2. The light emitted from each of the LEDs 1a to 1e is converted by the collimator lens 2 into a parallel light beam as a measurement light beam. The measurement light beam from the LED 1a is made into a parallel light beam P1 along the measurement optical axis O1 by the collimator lens 2, and the parallel light beam from the LEDs 1b to 1e becomes a parallel light beam having a known incident angle obliquely incident on the measurement optical axis O1. . In FIG. 12, the parallel light flux from the LED 1 b is indicated by the symbol P <b> 1 ′, and the parallel light flux from the LED 1 d is indicated by the symbolP1 "It is shown in
[0042]
The test lens TL is set in the measurement optical path 6 at the back surface vertex position X1 of the lens receiver 5 so that the position X3 decentered in the vertical direction from the optical axis O2 of the test lens TL faces the measurement optical path 6. . When the measurement is performed with the lens TL to be leveled, the position is set so that the position decentered in the front-rear direction faces the measurement optical path 6.
[0043]
  Each of these parallel light beams P1, P1 ',P1 "Is incident on the decentered position X3 of the test lens TL at a known incident angle, each parallel light beam P1, P1 ′, P1 ″ receives a different declination angle at the decentered position X3 of the test lens TL. Different power values are obtained depending on the aberration of the lens TL.
[0044]
Therefore, for example, when the LED 1d is turned on, a parallel light beam P1 "based on the LED 1d is incident on the test lens TL, refracted at the eccentric position X3 of the test lens TL, and passes through the opening 3a of the pattern plate 3 The aperture projection image 3a ′ is formed on the area sensor 4 by the luminous flux thus obtained, and the aperture projection image 3a ′ is calculated by the arithmetic circuit 30 to obtain the back focus value BF ″ as an optical characteristic value and the emission. An angle θ1 is obtained.
[0045]
That is, as shown in FIG. 2, the centers of the four openings 3a coincide with the measurement optical axis O1, but when measurement is performed at the position X where the lens TL is decentered, as shown in FIG. The aperture projection images 3a ′ are displaced as indicated by broken lines, for example, and the center positions W of the four aperture projection images 3a ′ are shifted from the measurement optical axis O1. Assuming the movement amount WX of the central position W of the four aperture projection images 3a ′ from the measurement optical axis O1, the exit angle θ1 has a known distance from the pattern plate 3 to the area sensor 4, and therefore Can be calculated using.
[0046]
θ1 = arctan (WX / d)
The prism amount can be calculated based on the exit angle.
[0047]
When the LED 1a is turned on, the parallel light beam P1 based on the LED 1a is incident on the decentered position X3 of the lens TL to be detected, and similarly, the back focus value BF and the emission angle θ2 are obtained. When the LED 1b is turned on, the back focus value BF 'is similarly obtained based on the parallel light flux P1' based on the LED 1b, and the emission angle θ3 is obtained.
[0048]
Therefore, when the relationship between the prism amount and the diopter is plotted on a graph, it is as shown in FIG. In FIG. 14, the horizontal axis represents the prism amount (PRISM), the vertical axis represents the reciprocal (frequency) of the back focus value, Q1 is a measurement point obtained based on the measurement light beam P1 ″, and Q2 is the measurement light beam. A measurement point obtained based on P1, Q3 represents a measurement point obtained based on the measurement light beam P1 ′.
[0049]
On the other hand, a decentered position X3 of the test lens TL using a lens meter of a type in which the measurement light beam is incident on the test lens TL from the concave surface side of the test lens TL and the power of the test lens TL is measured. As shown in FIG. 11, the back focus value when measuring is a value when the exit angle θ of the measurement light beam emitted from the lens TL to be measured becomes 0 degree.
[0050]
Therefore, the arithmetic circuit 30 performs linear approximation based on the obtained prism amount and the back focus value to obtain the straight line L, and obtains the back focus value BF0 when the prism amount is “0”. This back focus value BF0 theoretically matches the back focus value BF 'shown in FIG. The reciprocal of the back focus value BF0, that is, the frequency is displayed on the display 31.
[0051]
As a result, a parallel light beam is incident on the decentered position X3 of the test lens TL from the convex surface side of the test lens TL, and the power at the decentered position X3 of the test lens TL is obtained. A measurement light beam is incident from the concave surface side of the test lens TL, a parallel light beam is emitted from the convex surface side of the test lens TL, and the power at the eccentric position X3 of the test lens TL is obtained. Obtainable.
[0052]
Here, if the measurement light sources 1d, 1a, and 1b are turned on at the same time, the aperture projection image 3a ′ on the area sensor 4 cannot be distinguished, so the measurement light sources 1d, 1a, and 1b are turned on in time series. Thus, the aperture projection image 3a ′ by each measurement light source when the detection is performed by the area sensor 4 can be distinguished.
[0053]
Here, the back focus value and the prism amount are linearly approximated to determine the frequency when the prism amount is “0”. However, the back focus value and the prism are provided by providing a large number of LEDs, for example, seven or more LEDs. If the amount is obtained, and the frequency when the prism amount is “0” is obtained by curve approximation, the conversion accuracy is further improved. This curve approximation can be performed by plotting measured values of three or more points on the graph.
[0054]
According to the first embodiment, after the plurality of measurement light sources are sequentially turned on to obtain the back focus value, the calculation for conversion is performed. Therefore, the measurement is performed with one measurement light source turned on. The measurement takes time compared to the configuration, but when the power of the test lens TL is small, or when the amount of decentering (prism amount) is small, a parallel light beam is incident from the convex surface side of the test lens TL. There is almost no difference in the power at the position X3 where the lens TL is decentered between the lens and the lens that is incident from the concave surface side of the lens TL and emits the measurement light beam as a parallel light beam from the convex surface side. Since it can be considered, a predetermined threshold value is set for the back focus value at the eccentric position X3 of the test lens TL, and when the measurement result is equal to or less than the threshold value, only one LED is turned on. of Only when the threshold is exceeded, other LEDs are turned on to determine the back focus amount and the prism amount, and the measurement light beam is converted into a parallel light beam from the convex surface side of the lens TL by conversion. Assuming that the power that would be obtained when measuring with an output type is obtained, the power at the decentered position X3 of the lens TL to be tested is obtained without sacrificing operability as much as possible. Can do.
[0055]
In the measurement of the near portion of the progressive lens or bifocal lens, the measurement lens TL must be measured with a large decentration, but depending on whether the measurement lens TL is a convex lens or a concave lens, Since the declination direction is reversed, it is desirable that the measurement light beam is incident on the measurement optical axis O1 symmetrically.
[0056]
Further, when the test lens TL is a progressive lens or a bifocal lens, the near portion is automatically recognized, each LED 1a to 1e is automatically turned on, and a parallel light beam is projected from the convex surface side of the test lens TL. When the lens is provided with a memory button for storing the near portion of the test lens TL, and the measurer presses the button. Alternatively, it is possible to adopt a configuration in which the power at the eccentric position X3 of the test lens TL when the parallel light beam is emitted from the convex surface side of the test lens TL is employed.
[0057]
Further, which of the LEDs 1b to 1e is turned on based on the measurement result obtained by turning on the LED 1a and causing the parallel light beam P1 to enter the lens TL to be tested along the measurement optical axis O1 and turning on the LED 1a. A type in which the minimum required LEDs 1b to 1e other than the LED 1a are turned on, and the power at the eccentric position X3 of the lens TL is emitted from the convex surface side of the lens TL. It can also be set as the structure converted into the frequency in the eccentric position X3 of the to-be-tested lens TL obtained using this. With this configuration, the measurement time can be shortened.
[0058]
A conversion button is provided on the lens meter, and only the power (back focus value BF) S at the eccentric position X3 of the test lens TL when the parallel light beam P1 is incident from the convex surface side of the test lens TL is desired. In this case, when this conversion button is turned off and it is desired to obtain the frequency at the eccentric position X3 of the test lens TL when the parallel light beam P2 ′ is emitted from the convex surface side of the test lens TL, this conversion is performed. A configuration in which the button is turned on can also be adopted.
(Example 2)
FIG. 15 shows an optical system of a lens meter in which a measurement light beam is incident from the concave surface side of the test lens TL toward the test lens TL and a parallel light beam P2 is emitted from the convex surface side of the test lens TL. In FIG. 15, the same components as those in FIG.
[0059]
As shown in FIG. 16, the target plate 12 has five openings 12a to 12e. The opening 12a is located on the measurement optical axis O1, and four openings 12b to 12e are formed at equal intervals around the opening 12a. Reference numeral 15 ′ denotes an area sensor 15.
[0060]
It is assumed that the LEDs 10a to 10d are turned on and the measurement light flux is guided to the target plate 12 by the collimator lens 11. Further, it is assumed that the decentered position X3 of the test lens TL is on the measurement optical axis O1.
[0061]
When the target plate 12 is at the position indicated by the solid line in FIG. 15, the central opening 12a is conjugate with the area sensor 15 '. Here, when the LEDs 10b or 10d are individually turned on, as shown in FIG. 17A, five aperture projection images 12a ′, 12b ′, 12d ′, 12c ′, and 12e ′ of the target plate 12 are area sensors. 15 '. Since the test lens TL is decentered only in the vertical direction and not in the left-right direction, the aperture projection images when the LED 10b or 10d is turned on coincide.
[0062]
  LED10aIs turned on, aperture projection images 12a 'to 12e' shown in FIG. 17B are formed on the area sensor 15 '. In the left-right direction, the aperture projection images 12a ', 12c', and 12e 'coincide with each other. In the vertical direction, the projected aperture images 12b ', 12a', and 12d 'are shifted. This is because the measurement is performed on the assumption that the test lens TL is decentered only in the vertical direction.
[0063]
When the LED 10c is turned on, aperture projection images 12a 'to 12e' shown in Fig. 17C are formed. Accordingly, when the LEDs 10a to 10d are turned on at the same time, the aperture projection images 12a 'to 12e' are formed in the area sensor 15 'as shown in FIG.
[0064]
Assuming that the target plate 12 is moved along the measurement optical axis O1 and the opening 12b is in a conjugate position with the area sensor 15 ′, when the LEDs 10a to 10d are simultaneously turned on in the area sensor 15 ′, FIG. An aperture projection image shown in (e) is formed. On the area sensor 15, a point where five aperture projection images 12a 'to 12e' are overlapped at a position decentered from the measurement optical axis O1 is obtained. Further, the aperture projection images 12b ', 12a', and 12d 'are projected on the measurement optical axis O1 while being shifted in the vertical direction.
The left and right aperture projection images 12c 'and 12e' overlap the aperture projection image 12a '.
[0065]
  Therefore, the difference in the amount of movement when the target plate 12 is moved becomes the difference in power depending on the incident angle of the lens TL to be measured, and the aperture projection image at the area sensor 15 '.12a'-12e 'The target plate 12 is moved so as to overlap one point, and the difference in power at each moving position is obtained to obtain a parallel light beam incident from the convex surface side of the test lens. The frequency when measurement is performed at an eccentric position can be obtained by conversion.
[0066]
The prism amount is obtained as the distance between the gravity center positions of the four projected images obtained when the LEDs 10a to 10d are turned on simultaneously and the measurement optical axis O1.
[0067]
In the second embodiment, the configuration in which the center positions of the four projected images are obtained using the area sensor 15 ′ is adopted. However, instead of the area sensor 15 ′, a line sensor is used, and a plurality of openings are used as the openings of the target plate 12. It can also be set as the structure which combined these slits.
(Example 3)
FIG. 18 is a diagram showing an optical system of a lens meter using a detection method, in which a collimating lens 2 is used to allow a parallel light beam to enter the lens TL, and the lens TL to be tested is set in the measurement optical path 6. If not, the light source images of the LEDs 1a and 1b are formed at a position eccentric from the rotation axis O3 of the rotating pattern plate 41 using the condenser lens 40. A predetermined opening pattern is formed in the rotation pattern plate 41, and the rotation pattern plate 41 is rotated at a constant cycle about the rotation axis O3.
[0068]
When the test lens TL is a convex lens, a focused light source image of the LEDs 1a and 1b is formed on the front side of the rotation pattern plate 41. When the test lens TL is a concave lens, the LEDs 1a and 1b are provided on the rear side of the rotation pattern plate 41. An in-focus light source image is formed. An imaging lens 42 is disposed between the rotation pattern plate 41 and the area sensor 4, the front focal point of the imaging lens 42 coincides with the rotation pattern plate 41, and the test lens TL is set in the measurement optical path 6. When not, the light beams emitted from the LEDs 1a and 1b are guided to the area sensor 4 as parallel light beams.
[0069]
When the test lens TL is not set in the measurement optical path 6, a focused light source image is formed at the position where the rotary pattern plate 41 is disposed. Therefore, when the opening of the rotary pattern plate 41 crosses the light source image, an area is formed. The output of the sensor 4 increases rapidly, and when the light shielding part of the rotating pattern plate 41 crosses the light source image, the output of the area sensor 4 decreases rapidly.
[0070]
When the test lens TL is set in the measurement optical path 6, it is formed on the front side (when the test lens TL is a convex lens) or the rear side (when the test lens TL is a concave lens) of the position where the rotation pattern plate 41 is disposed. Since the light source images of the LEDs 1a and 1b are blurred on the rotating pattern plate 41, when the opening of the rotating pattern plate 41 crosses the light source image, the increase in the light reception output of the area sensor 41 becomes gradual, and the rotation Even when the light-shielding portion of the pattern plate 41 crosses the light source image, the decrease in the light reception output of the area sensor 4 becomes more gradual, and the greater the power of the lens TL to be measured, the more the front focus from the position where the rotation pattern plate 41 is disposed. Since the amount of deviation up to the position or the rear focus position increases, and as the aberration of the lens TL to be measured increases, the amount of deviation increases. LEDs 1a, the blur amount of the light source image of 1b becomes large.
[0071]
Accordingly, the degree of tendency of increase / decrease in the light reception output of the area sensor 4, the frequency at the decentered position X3 of the lens TL to be measured, and the prism amount can be obtained according to how the increase / decrease appears, and the LEDs 1a, 1b are sequentially turned on, If the power and prism amount of each LED 1a, 1b are obtained, the same measurement result as shown in FIG. 14 can be obtained.
[0072]
The details of the lens meter measurement by this detection method are described in Japanese Patent Application Laid-Open No. 2000-266639.
[0073]
【The invention's effect】
According to the present invention, a measurement principle type is used in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens and the optical characteristics of the test lens are obtained by displacement of the measurement light beam after passing through the test lens. When measuring the optical characteristics at the eccentric position of the test lens using a target, the target light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. When measuring the optical characteristics at the decentered position of the test lens using the measurement principle type that calculates the optical characteristics of the test lens based on the amount of movement of the target plate when the plate is moved along the measurement optical axis Thus, the mismatch of the optical characteristics can be eliminated.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an optical system of a lens meter of a type in which a parallel light beam is incident from the convex surface side of a test lens and optical characteristics of the test lens are obtained by displacement of a measurement light beam after passing through the test lens.
FIG. 2 is a plan view of the pattern plate shown in FIG.
3 is an explanatory view showing an aperture projection image formed on an area sensor sensor when a test lens is not set in the measurement optical path of the optical system shown in FIG. 1; FIG.
4 is an explanatory diagram of an aperture projection image formed on an area sensor when a test lens having a positive power is set in the measurement optical path of the optical system shown in FIG. 1; FIG.
FIG. 5 is a type of lens meter that obtains optical characteristics of a test lens based on the amount of movement of the target plate by moving the target plate along the measurement optical axis and emitting a parallel light beam from the convex surface side of the test lens. It is a schematic diagram which shows this optical system.
6 is a plan view for explaining an arrangement configuration of measurement light sources shown in FIG. 5. FIG.
7 is a plan view of the target plate shown in FIG.
FIG. 8 is a diagram illustrating the setting of the target lens in the measurement optical path so that a parallel light beam is emitted from the convex surface side of the test lens when the test lens is set in the measurement optical path of the measurement principle type lens meter shown in FIG. It is a schematic diagram for demonstrating the state moved along.
9 is a schematic diagram for explaining a back focus value obtained when measurement is performed with a decentered position of a test lens facing a measurement optical path of the measurement principle type lens meter shown in FIG. 1; FIG.
FIG. 10 is a schematic diagram for explaining a back focus value obtained when measurement is performed with a decentered position of a test lens facing a measurement optical path of the measurement principle type lens meter shown in FIG. 5;
11 shows a back focus value at a decentered position of a test lens obtained by measurement using the measurement principle type lens meter shown in FIG. 1 and measurement using the measurement principle type lens meter shown in FIG. FIG. 6 is a schematic diagram illustrating the difference between the defocused position and the back focus value obtained at the time when the lens to be tested is overlapped.
FIG. 12 shows a measurement principle type in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens and the optical characteristics of the test lens are obtained by displacement of the measurement light beam after passing through the test lens. When measuring the optical characteristics at the eccentric position of the test lens, the target plate is placed so that the measurement light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. When measuring the optical characteristics at the decentered position of the test lens using a measurement principle type that obtains the optical characteristics of the test lens based on the amount of movement of the target plate when moved along the measurement optical axis. FIG. 2 is an explanatory diagram for explaining that a plurality of measurement light sources are provided in the optical system of the measurement principle type shown in FIG. 1 in order to eliminate the mismatch of the optical characteristics.
13 is an explanatory diagram showing an arrangement state of a plurality of measurement light sources shown in FIG. 12. FIG.
14 is a graph plotting measurement results obtained when the decentered position of the lens to be tested is measured using the optical system of the lens meter shown in FIG. 12. FIG.
FIG. 15 shows a measurement principle type in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens and the optical characteristics of the test lens are obtained by displacement of the measurement light beam after passing through the test lens. When measuring the optical characteristics at the eccentric position of the test lens, the target plate is placed so that the measurement light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. When measuring the optical characteristics at the decentered position of the test lens using a measurement principle type that obtains the optical characteristics of the test lens based on the amount of movement of the target plate when moved along the measurement optical axis. FIG. 3 is an explanatory diagram showing a state in which a target plate having a plurality of openings is provided in the optical system in order to eliminate the mismatch in optical characteristics.
16 is a plan view of the target plate shown in FIG.
FIG. 17 is a schematic diagram for explaining an aperture projection image formed on an area sensor based on a light beam that has passed through a target plate.
FIG. 18 is an explanatory diagram of a lens meter based on a detection method.
[Explanation of symbols]
O1 ... Measurement optical axis
TL ... Test lens
X3 ... Eccentric position
P1, P1 ', P1 "... Parallel luminous flux

Claims

Tested using a measurement principle type lens in which a parallel beam as a measurement beam is incident on the test lens from the convex surface side of the test lens and the optical characteristics of the test lens are obtained by displacement of the measurement beam after passing through the test lens When measuring the optical characteristics at the decentered position of the lens, the target plate is used as the measurement optical axis so that the measurement light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. When measuring the optical characteristics at the decentered position of the test lens using a measurement principle type that obtains the optical characteristics of the test lens based on the amount of movement of the target plate when moving along the optical characteristics. To resolve this discrepancy,
A measurement principle type optical system in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens, and a configuration in which a parallel light beam oblique to the measurement optical axis is incident on the test lens as a measurement light beam. The optical characteristic value at the decentered position of the test lens obtained by allowing the parallel light beam parallel to the measurement optical axis to enter the test lens, and the oblique parallel light beam from the convex surface side of the test lens are tested. The target plate is used as a measurement optical axis so that a parallel light beam as a measurement light beam is emitted from the convex surface side of the test lens based on the optical characteristic value at the eccentric position of the test lens obtained by entering the lens. A lens meter characterized by obtaining an optical characteristic value at a decentered position of a lens to be measured using a measuring principle type that is moved along .

2. The lens meter according to claim 1, wherein the parallel light flux incident from an oblique direction with respect to the measurement optical axis is vertically and horizontally symmetrical with respect to the measurement optical axis.

The lens meter according to claim 1, wherein a measurer can select a parallel light beam used for measurement at an eccentric position of the test lens.

The optical characteristic value at the eccentric position of the test lens obtained by the measurement principle type in which a parallel light beam as the measurement light beam is incident on the test lens from the convex surface side of the test lens is measured from the concave surface side of the test lens. Is a measurement principle type that determines the optical characteristics of the test lens by the amount of movement of the target plate when the target plate is moved along the measurement optical axis so that a parallel beam is emitted from the convex surface side. The lens according to claim 1, wherein a measurer can determine and set whether or not to convert to an optical characteristic value at a decentered position of the lens to be obtained obtained by using the lens. Meter.

The optical characteristic value at the eccentric position of the test lens obtained by the measurement principle type in which a parallel light beam as the measurement light beam is incident on the test lens from the convex surface side of the test lens is measured from the concave surface side of the test lens. Is a measurement principle type that determines the optical characteristics of the test lens by the amount of movement of the target plate when the target plate is moved along the measurement optical axis so that a parallel beam is emitted from the convex surface side. Whether or not to convert to an optical characteristic value at the eccentric position of the test lens obtained by using the above, the parallel light beam incident on the test lens from the convex surface side of the test lens along the measurement optical axis Automatically determine the parallel light flux incident on the test lens from the convex side of the test lens from the oblique direction along the measurement optical axis. It is characterized by Lens meter according to claim 1.

The lens meter according to claim 1, wherein a pattern plate having a plurality of openings is provided at a rear position of the test lens.

Tested using a measurement principle type lens in which a parallel beam as a measurement beam is incident on the test lens from the convex surface side of the test lens and the optical characteristics of the test lens are obtained by displacement of the measurement beam after passing through the test lens When measuring the optical characteristics at the decentered position of the lens, the target plate is used as the measurement optical axis so that the measurement light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. When measuring the optical characteristics at the decentered position of the test lens using a measurement principle type that obtains the optical characteristics of the test lens based on the amount of movement of the target plate when moving along the optical characteristics. To resolve this discrepancy,
A plurality of apertures are formed in the target plate of a measurement principle type optical system that moves the target plate so that a parallel light beam as a measurement light beam is emitted from the convex surface side of the test lens, and at an eccentric position of the test lens. A lens meter characterized in that a measurement person can select a measurement light beam used for measurement of light .

A parallel light beam as the measurement light beam is incident on the test lens from the convex side of the test lens. And measuring the optical characteristics at the decentered position of the test lens using a measurement principle type that obtains the optical characteristics of the test lens by the displacement of the measurement light beam after passing through the test lens, Optical characteristics of the test lens by the amount of movement of the target plate when the target plate is moved along the measurement optical axis so that the measurement light beam enters the test lens from the concave surface side and the parallel light beam is emitted from the convex surface side In order to eliminate the discrepancy of the optical characteristics when measuring the optical characteristics at the eccentric position of the lens to be measured using the measurement principle type
A plurality of apertures are formed in the target plate of a measurement principle type optical system in which the target plate is moved so that a parallel light beam as a measurement light beam is emitted from the convex surface side of the test lens, and measurement is performed from the concave surface side of the test lens. Optical characteristic value at the eccentric position of the test lens obtained by the measurement principle type that moves the target plate along the measurement optical axis so that the light beam enters the test lens and the parallel light beam is emitted from the convex surface side Is converted into an optical characteristic value at an eccentric position of the test lens obtained by using a measurement principle type in which a parallel light beam as a measurement light beam is incident on the test lens from the convex surface side of the test lens A lens meter, wherein a measurer can determine and set whether or not.

Tested using a measurement principle type lens in which a parallel beam as a measurement beam is incident on the test lens from the convex surface side of the test lens and the optical characteristics of the test lens are obtained by displacement of the measurement beam after passing through the test lens When measuring the optical characteristics at the decentered position of the lens, the target plate is used as the measurement optical axis so that the measurement light beam is incident on the test lens from the concave surface side of the test lens and the parallel light beam is emitted from the convex surface side. When measuring the optical characteristics at the decentered position of the test lens using a measurement principle type that obtains the optical characteristics of the test lens based on the amount of movement of the target plate when moving along the optical characteristics. To resolve this discrepancy,
A plurality of apertures are formed in the target plate of a measurement principle type optical system in which the target plate is moved so that a parallel light beam as a measurement light beam is emitted from the convex surface side of the test lens, and measurement is performed from the concave surface side of the test lens. Optical characteristic value at the eccentric position of the test lens obtained by the measurement principle type that moves the target plate along the measurement optical axis so that the light beam enters the test lens and the parallel light beam is emitted from the convex surface side Whether or not to be converted into an optical characteristic value at an eccentric position of the test lens obtained by using a measurement principle type in which a parallel light beam as a measurement light beam enters the test lens from the convex surface side of the test lens A lens meter that automatically determines whether or not based on a measured light beam .

In a measurement principle type lens meter that moves a target plate along a measurement optical axis so that a measurement light beam is incident on the test lens from the concave surface side of the test lens and a parallel light beam is emitted from the convex surface side. A lens meter, wherein when measuring an optical characteristic value at a decentered position, the measurement is performed through an opening deviated from the measurement optical axis of the target plate.