JP4366764B2

JP4366764B2 - Focus detection device

Info

Publication number: JP4366764B2
Application number: JP19185599A
Authority: JP
Inventors: 正光小澤
Original assignee: Nikon Corp
Current assignee: Nikon Corp
Priority date: 1999-07-06
Filing date: 1999-07-06
Publication date: 2009-11-18
Anticipated expiration: 2019-07-06
Also published as: JP2001021797A

Description

【０００１】
【産業上の利用分野】
本発明は一眼レフカメラ等に用いられる焦点検出装置に関するものである。
【０００２】
【従来の技術】
一般的に複数の焦点検出領域を備える焦点検出装置は、図３，４に示すような位相差検出方式のものが知られている。図３は、従来の焦点検出装置の概略的な構成を示す斜視図、図４は、図３に示す焦点検出装置９０を図のｙ軸方向から見た模式的な光路図である。被写界からの光束は不図示の撮影レンズを介して視野マスク２０近傍に結像する。被写界からの光束のうち、ｘ軸方向に延びた矩形の視野開口２２を通る光束は、図４に示す主光線ｒ２ａ，ｒ２ｂのように、コンデンサーレンズ３０のレンズ部３２を介し、撮影レンズの射出瞳とほぼ共役な位置に配置された絞りマスク４０の絞り開口４３，４４および再結像光学系５０の再結像レンズ部５３，５４を介して分割され、それぞれＣＣＤチップ６０の受光素子列６３，６４上に結像する。
【０００３】
そして、受光素子列６３，６４上に結像された一対の被写体像を光電変換することにより、撮影レンズの焦点調節状態を検出することができる。つまり、撮影レンズの焦点調節状態が、フィルム等価面上に鮮鋭像を結ぶ、いわゆる合焦時では、受光素子列６３，６４上の一対の被写体像のそれぞれの位置は、前ピン状態と後ピン状態との間の所定の間隔で結像する。また、撮影レンズの焦点調節状態がフィルム等価面よりも前方に鮮鋭像を結ぶ、いわゆる前ピン状態のときには、受光素子列６３，６４上の一対の被写体像のそれぞれの位置は、所定の間隔より短い第１の間隔で結像する。逆に、撮影レンズの焦点調節状態がフィルム等価面よりも後方に鮮鋭像を結ぶ、いわゆる後ピン状態のときには、受光素子列６３，６４上の一対の被写体像のそれぞれの位置は、所定の間隔より長い第２の間隔で結像する。したがって、この一対の被写体像を受光素子列６３，６４で光電変換して電気信号に変え、例えば特開昭６０−３７５１３号公報に開示されたずれ量検出装置のように、これらの電気信号から相関演算等を行うことにより一対の被写体像の相対位置ずれ量が求まり、視野開口２２に対応する焦点検出領域での撮影レンズの焦点調節状態が検出される。
【０００４】
また、被写界からの光束のうち視野マスク２０のｙ軸方向に延びた矩形の視野開口２１を通る光束は、図４に示す主光線ｒ２ｃ，ｒ２ｄのように、コンデンサーレンズ３０のレンズ部３１を介し、絞りマスク４０の絞り開口４１，４２および再結像光学系５０の再結像レンズ部５１，５２を介して分割され、それぞれＣＣＤチップ６０の受光素子列６１，６２上に結像する。同様に、視野開口２３を通る光束は、図４に示す主光線ｒ２ｅ，ｒ２ｆのように、コンデンサーレンズ３０のレンズ部３３を介し、絞りマスク４０の絞り開口４５，４６および再結像光学系５０の再結像レンズ部５５，５６を介して分割され、それぞれＣＣＤチップ６６の受光素子列６５，６６上に結像する。そして、受光素子列６１，６２上の一対の被写体像により視野開口２１に、受光素子列６５，６６上の一対の被写体像により視野開口２３に対応する光軸外の焦点検出領域での撮影レンズの焦点状態が検出される。
【０００５】
このようにして、複数の焦点検出領域の焦点検出を可能にしていた。
また、特開平２−５０１１５号公報では、撮影画面の対角線上に焦点検出領域を配置した焦点検出装置が開示されている。
【０００６】
【発明が解決しようとする課題】
以上のように、撮影画面内に複数の焦点検出領域を設けると、受光素子列に一対の被写体像を結像するための絞り開口と再結像レンズ部とが、一つの焦点検出領域に対してそれぞれ一対ずつ必要となる。また、ｘ軸方向に延びた矩形の視野開口２２による焦点検出領域では、ｘ軸方向に輝度変化を持つ被写体に対しては焦点検出を行うことができず、ｙ軸方向に延びた矩形の視野開口２１，２３による焦点検出領域では、ｙ軸方向に輝度変化を持つ被写体に対しては焦点検出を行うことができなかった。
【０００７】
特開平２−５０１１５号公報では、焦点検出領域の数を増やしてより多くの位置で焦点検出を行えるようにするために、撮影画面の対角線上にも焦点検出領域を配置しているが、各焦点検出領域に対してそれぞれ一対の絞り開口と一対の再結像レンズ部とが必要となる。また、クロス状の視野開口に対応する焦点検出領域では、二対ずつの絞りマスクと再結像レンズ部が必要となり、焦点検出装置が大型化し、焦点検出光学系自体が複雑化するという問題がある。
【０００８】
本発明の目的は、上記の従来の技術の欠点を解消し、焦点検出領域を多数備えているにもかかわらず、焦点検出光学系の構成を簡素化し、すべての焦点検出領域で苦手とする被写体を大幅に減らすことができる焦点検出装置を提供することにある。
【０００９】
【課題を解決するための手段】
上記目的を達成するために、請求項１の発明は、撮影レンズ（１００）の予定結像面近傍に配置されるとともに、第１および第２の焦点検出領域に対応した複数の視野開口（２０１，２０２）を備える視野マスク（２００）と、視野マスク（２００）の複数の視野開口（２０１，２０２）を透過した光束をそれぞれ集光する複数のレンズ部（３０１，３０２）を備えるコンデンサーレンズ（３００）と、複数の視野開口（２０１，２０２）のそれぞれを透過した光束を、撮影レンズ（１００）の射出瞳の異なる領域を透過した一対の光束に分割する複数の絞り開口（４０１，４０２，４０３，４０４，４０５，４０６，４０７，４０８）を備える絞りマスク（４００）と、複数の視野開口（２０１，２０２）の像を受光手段（６００）上に結像させる複数の再結像レンズ部（５０１，５０２，５０３，５０４，５０５，５０６，５０７，５０８）を備える再結像光学系（５００）とを有する焦点検出装置において、第１と第２の焦点検出領域の中心を結ぶ線上とは異なる位置に、クロス状の視野開口（２０４）を持つ焦点検出領域をさらに有し、クロス状の視野開口（２０４）のうちの一方の矩形の視野開口を透過する像は第１の焦点検出領域に対応した絞り開口（４０１，４０４）と再結像レンズ部（５０１，５０４）を、他方の矩形の視野開口を透過する像は第２の焦点検出領域に対応した絞り開口（４０６，４０８）と再結像レンズ部（５０６，５０８）を用いることを特徴とする。
【００１０】
請求項２の発明は、前記焦点検出領域は、すべてクロス状の視野開口を持つことを特徴とする。
請求項３の発明は、クロス状の視野開口（２０４）が前記第１および第２の焦点検出領域に対応した視野開口（２０１，２０２）に対して傾斜した傾斜部を有することを特徴とする。
請求項４の発明は、撮影レンズ（１００）による像面内の互いに異なる位置に設定された第１から第３の焦点検出領域に対応した第１から第３の視野開口（２０１，２０１，２０４）を備える視野マスク（２００）と、視野マスク（２００）より撮影レンズ（１００）の像側に配置され、前記第１の視野開口（２０１）を通過した光束を前記撮影レンズ（１００）の異なる領域を透過した一対の光束に分割する第１の絞り開口対（４０１，４０２）と、第２の視野開口（２０１）を通過した光束を前記撮影レンズの異なる領域を透過した一対の光束に分割する第２の絞り開口対（４０３，４０４）とを備える絞りマスク（４００）と、絞りマスク（４００）より撮影レンズ（１００）の像側に配置され、第１の絞り開口対（４０１，４０２）によって分割された一対の光束による像を受光手段（６００）上に結像させる第１の再結像レンズ対（５０１，５０２）と、第２の絞り開口対（４０３，４０４）によって分割された一対の光束による像を受光手段（６００）上に結像させる第２の再結像レンズ対（５０３，５０４）とを備える再結像光学系（５００）とを有し、受光手段（６００）は、第１の絞り開口対（４０１，４０２）のうちの一方の開口（４０１）および第１の再結像レンズ対（５０１，５０２）のうちの一方のレンズ（５０１）を介して第３の視野開口（２０４）を通過した光束を受光する第１の受光部（６１５）と、第２の絞り開口対（４０３，４０４）のうちの一方の開口（４０４）および第２の再結像レンズ対（５０３，５０４）のうちの一方のレンズ（５０４）を介して第３の視野開口（２０４）を通過した光束を受光する第２の受光部（６１６）とを備えることを特徴とする。
請求項５の発明は、第１の視野開口（２０１）と第２の視野開口（２０１）が互いに交差して設けられ、第３の視野開口（２０４）が第１および第２の視野開口（２０１，２０１）に対して傾斜していることを特徴とする。
【００１１】
【発明の実施の形態】
図１は、本発明による焦点検出装置の概略的な構成を示す斜視図、図２は、ＣＣＤチップを被写体側から見た場合の正面図である。被写界からの光束は、撮影レンズ１００を介して視野マスク２００近傍に結像する。この視野マスク２００は複数の視野開口２０１，２０２，２０３，２０４，２０５，２０６，２０７を有し、視野開口２０２は撮影画面中央の焦点検出領域に対応し、視野開口２０１，２０３は撮影レンズ１００の光軸Ｌから外れた位置の焦点検出領域に対応し、視野開口２０４，２０５，２０６，２０７は視野開口２０１，２０２，２０３に対応する焦点検出領域のうちの少なくとも２つの焦点検出領域の中心を結ぶ線上とは異なる位置の焦点検出領域に対応する。コンデンサーレンズ３００は、レンズ部３０１，３０２，３０３，３０４，３０５，３０６，３０７を有する。
【００１２】
視野開口２０１，２０２，２０３を透過する像について詳細に説明すると、被写界からの光束のうち、視野開口２０２のｘ軸方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０２を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の絞り開口４０５，４０６および再結像光学系５００の再結像レンズ部５０５，５０６を介して分割され、それぞれＣＣＤチップ６００の受光素子列６０５，６０６上に結像する。視野開口２０２のｙ軸方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０２を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の絞り開口４０７，４０８および再結像光学系５００の再結像レンズ部５０７，５０８を介して分割され、それぞれＣＣＤチップ６００の受光素子列６０７，６０８上に結像する。
【００１３】
また、被写界からの光束のうち、視野開口２０１のｘ軸方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０１を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の絞り開口４０１，４０２および再結像光学系５００の再結像レンズ部５０１，５０２を介して分割され、それぞれＣＣＤチップ６００の受光素子列６０１，６０２上に結像する。視野開口２０１のｙ軸方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０１を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の絞り開口４０３，４０４および再結像光学系５００の再結像レンズ部５０３，５０４を介して分割され、それぞれＣＣＤチップ６００の受光素子列６０３，６０４上に結像する。
【００１４】
さらに、被写界からの光束のうち、視野開口２０１とは反対側の視野開口２０３のｘ軸方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０３を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の絞り開口４０９，４１０および再結像光学系５００の再結像レンズ部５０９，５１０を介して分割され、それぞれＣＣＤチップ６００の受光素子列６０９，６１０上に結像する。視野開口２０３のｙ軸方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０３を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の絞り開口４１１，４１２および再結像光学系５００の再結像レンズ部５１１，５１２を介して分割され、それぞれＣＣＤチップ６００の受光素子列６１１，６１２上に結像する。
【００１５】
このように、視野開口２０１，２０２，２０３に対応する焦点検出領域は、それぞれ独自の二対ずつ（クロス状の視野開口であるため）の絞り開口４０１，４０２，４０３，４０４，４０５，４０６，４０７，４０８，４０９，４１０，４１１，４１２と再結像レンズ部５０１，５０２，５０３，５０４，５０５，５０６，５０７，５０８，５０９，５１０，５１１，５１２を用いている。
【００１６】
視野開口２０４，２０５，２０６，２０７を透過する像について詳細に説明すると、被写界からの光束のうち、視野開口２０４の撮影レンズ１００の光軸Ｌに対して円周方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０４を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２に対応する絞り開口である絞り開口４０６，４０８および再結像光学系５００の視野開口２０２に対応する再結像レンズ部である再結像レンズ部５０６，５０８を介して分割され、それぞれＣＣＤチップ６００の受光素子列６２３，６２４上に結像する。視野開口２０４の撮影レンズ１００の光軸Ｌに対して径方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０４を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２とは異なる視野開口２０１に対応する絞り開口である絞り開口４０１，４０４および再結像光学系５００の視野開口２０２とは異なる視野開口２０１に対応する再結像レンズ部である再結像レンズ部５０１，５０４を介して分割され、それぞれＣＣＤチップ６００の受光素子列６１５，６１６上に結像する。
【００１７】
また、被写界からの光束のうち、視野開口２０５の撮影レンズ１００の光軸Ｌに対して円周方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０５を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２に対応する絞り開口である絞り開口４０６，４０７および再結像光学系５００の視野開口２０２に対応する再結像レンズ部である再結像レンズ部５０６，５０７を介して分割され、それぞれＣＣＤチップ６００の受光素子列６２１，６２２上に結像する。視野開口２０５の撮影レンズ１００の光軸Ｌに対して径方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０５を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２とは異なる視野開口２０１に対応する絞り開口である絞り開口４０１，４０３および再結像光学系５００の視野開口２０２とは異なる視野開口２０１に対応する再結像レンズ部である再結像レンズ部５０１，５０３を介して分割され、それぞれＣＣＤチップ６００の受光素子列６１３，６１４上に結像する。
【００１８】
さらに、被写界からの光束のうち、視野開口２０６の撮影レンズ１００の光軸Ｌに対して円周方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０６を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２に対応する絞り開口である絞り開口４０５，４０８および再結像光学系５００の視野開口２０２に対応する再結像レンズ部である再結像レンズ部５０５，５０８を介して分割され、それぞれＣＣＤチップ６００の受光素子列６１９，６２０上に結像する。視野開口２０６の撮影レンズ１００の光軸Ｌに対して径方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０６を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２とは異なる視野開口２０３に対応する絞り開口である絞り開口４１０，４１２および再結像光学系５００の視野開口２０２とは異なる視野開口２０３に対応する再結像レンズ部である再結像レンズ部５１０，５１２を介して分割され、それぞれＣＣＤチップ６００の受光素子列６２７，６２８上に結像する。
【００１９】
さらにまた、被写界からの光束のうち、視野開口２０７の撮影レンズ１００の光軸Ｌに対して円周方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０７を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２に対応する絞り開口である絞り開口４０５，４０７および再結像光学系５００の視野開口２０２に対応する再結像レンズ部である再結像レンズ部５０５，５０７を介して分割され、それぞれＣＣＤチップ６００の受光素子列６１７，６１８上に結像する。視野開口２０７の撮影レンズ１００の光軸Ｌに対して径方向に延びた矩形の開口部を通る光束は、コンデンサーレンズ３００のレンズ部３０７を介し、撮影レンズ１００の射出瞳とほぼ共役な位置に配置された絞りマスク４００の視野開口２０２とは異なる視野開口２０３に対応する絞り開口である絞り開口４１０，４１１および再結像光学系５００の視野開口２０２とは異なる視野開口２０３に対応する再結像レンズ部である再結像レンズ部５１０，５１１を介して分割され、それぞれＣＣＤチップ６００の受光素子列６２５，６２６上に結像する。
【００２０】
このように、視野開口２０４，２０５，２０６，２０７を透過する光束は、視野開口２０１，２０２，２０３に対応する焦点検出領域に対応した絞り開口と再結像レンズ部を用いている。図２において、視野開口と視野開口像との関係を説明する。視野開口２０１は視野開口像７０１，７０２，７０３，７０４に、視野開口２０２は視野開口像７０５，７０６，７０７，７０８に、視野開口２０３は視野開口像７０９，７１０，７１１，７１２に、視野開口２０４は視野開口像７１５，７１６、７２３，７２４に、視野開口２０５は視野開口像７１３，７１４，７２１，７２２に、視野開口２０６は視野開口像７１９，７２０，７２７，７２８に、視野開口２０７は視野開口像７１７，７１８，７２５，７２６にそれぞれ対応する。
【００２１】
以上の構成では、例えば、絞りマスク４００の絞り開口４０５および再結像レンズ５００のレンズ部５０５を、視野マスク２００の視野開口２０２，２０６および２０７で共用する。つまり、異なる視野開口からの光束でも、同一の絞り開口および再結像レンズ部を用いている。したがって、焦点検出光学系の構成を大幅に簡素化することができる。
【００２２】
また、視野開口２０１，２０２，２０３に対応する焦点検出領域のうちの少なくとも２つの焦点検出領域の中心を結ぶ線上とは異なる位置に配置された焦点検出領域の絞り開口および再結像レンズ部は、撮影レンズ１００の光軸Ｌに対して円周方向に延びた矩形と径方向に延びた矩形とで、視野開口２０１，２０２，２０３のうちのそれぞれ異なる視野開口に対応した絞り開口および再結像レンズ部を用いているので、すべての焦点検出領域でクロス状の焦点検出領域を構成でき、焦点検出に苦手とする被写体を大幅に減らすことができる。
【００２３】
【発明の効果】
以上のように請求項１によれば、それぞれ独自の絞り開口と再結像レンズ部を用いる第１と第２の焦点検出領域の中心を結ぶ線上とは異なる位置に、クロス状の視野開口を持つ焦点検出領域を有し、クロス状の視野開口のうちの一方の矩形の視野開口を透過する像は第１の焦点検出領域に対応した絞り開口と再結像レンズ部を、他方の矩形の視野開口を透過する像は第２の焦点検出領域に対応した絞り開口と再結像レンズ部を用いるようにしたので、焦点検出光学系の構成要素が大幅に簡素化できる。
【００２４】
また、請求項２によれば、請求項１の焦点検出装置において、すべての焦点検出領域をクロス状の視野開口を持つようにしたので、焦点検出光学系の構成要素を増やすことなく、焦点検出に苦手とする被写体を大幅に減らすことが可能となる。
また、請求項３によれば、請求項１または２の焦点検出装置において、クロス状の視野開口が第１および第２の焦点検出領域に対応した視野開口に対して傾斜した傾斜部を有するようにしたので、焦点検出に苦手とする被写体を大幅に減らすことが可能となる。
また、請求項４によれば、受光手段が第１の絞り開口対のうちの一方の開口および第１の再結像レンズ対のうちの一方のレンズを介して第３の視野開口を通過した光束を受光する第１の受光部と、第２の絞り開口対のうちの一方の開口および第２の再結像レンズ対のうちの一方のレンズを介して第３の視野開口を通過した光束を受光する第２の受光部とを備えるようにしたので、焦点検出光学系の構成要素が大幅に簡素化できる。
また、請求項５によれば、請求項４の焦点検出装置において、第１の視野開口と第２の視野開口が互いに交差して設けられ、第３の視野開口が第１および第２の視野開口に対して傾斜しているようにしたので、焦点検出に苦手とする被写体を大幅に減らすことが可能となる。
【図面の簡単な説明】
【図１】本発明の焦点検出装置の概略的な構成を示す斜視図である。
【図２】本発明の焦点検出装置におけるＣＣＤチップを示す正面図である。
【図３】従来の焦点検出装置の概略的な構成を示す斜視図である。
【図４】図３に示す焦点検出装置の模式的な光路図である。
【符号の説明】
２０，２００視野マスク
２１〜２３，２０１〜２０７視野開口
３０，３００コンデンサーレンズ
３１〜３３，３０１〜３０７コンデンサーレンズのレンズ部
４０，４００絞りマスク
４１〜４６，４０１〜４１２絞りマスクの絞り開口
５０，５００再結像光学系
５１〜５６，５０１〜５１２再結像光学系の再結像レンズ部
６０，６００ＣＣＤチップ
６１〜６６，６０１〜６２８受光素子列
７０１〜７２８視野開口像
９０，９００焦点検出装置
１００撮影レンズ[0001]
[Industrial application fields]
The present invention relates to a focus detection device used for a single-lens reflex camera or the like.
[0002]
[Prior art]
In general, a focus detection apparatus having a plurality of focus detection areas is known as a phase difference detection method as shown in FIGS. FIG. 3 is a perspective view showing a schematic configuration of a conventional focus detection device, and FIG. 4 is a schematic optical path diagram of the focus detection device 90 shown in FIG. 3 viewed from the y-axis direction of the figure. The light flux from the object field forms an image near the field mask 20 through a photographing lens (not shown). Of the luminous flux from the object field, the luminous flux that passes through the rectangular field opening 22 extending in the x-axis direction passes through the lens portion 32 of the condenser lens 30 like the principal rays r2a and r2b shown in FIG. The light receiving elements of the CCD chip 60 are divided through the aperture openings 43 and 44 of the aperture mask 40 and the re-imaging lens portions 53 and 54 of the re-imaging optical system 50, which are arranged at positions almost conjugate to the exit pupil of the CCD chip 60. An image is formed on the columns 63 and 64.
[0003]
The focus adjustment state of the photographic lens can be detected by photoelectrically converting a pair of subject images formed on the light receiving element arrays 63 and 64. In other words, when the focus adjustment state of the photographic lens forms a sharp image on the film equivalent surface, so-called in-focus state, the positions of the pair of subject images on the light receiving element arrays 63 and 64 are the front pin state and the rear pin. The image is formed at a predetermined interval between the states. When the focus adjustment state of the photographic lens is a so-called front pin state in which a sharp image is formed ahead of the film equivalent surface, the positions of the pair of subject images on the light receiving element rows 63 and 64 are more than a predetermined interval. An image is formed at a short first interval. Conversely, when the focus adjustment state of the photographic lens is a so-called rear pin state in which a sharp image is formed behind the film equivalent surface, the positions of the pair of subject images on the light receiving element rows 63 and 64 are set at predetermined intervals. An image is formed at a longer second interval. Therefore, the pair of subject images are photoelectrically converted by the light receiving element rows 63 and 64 to be converted into electric signals. From the electric signals, for example, as in the deviation amount detection device disclosed in Japanese Patent Application Laid-Open No. 60-37513. By performing correlation calculation or the like, the amount of relative positional deviation between the pair of subject images is obtained, and the focus adjustment state of the photographing lens in the focus detection region corresponding to the field opening 22 is detected.
[0004]
Further, of the light flux from the object scene, the light flux passing through the rectangular field opening 21 extending in the y-axis direction of the field mask 20 is the lens portion 31 of the condenser lens 30 as shown in the principal rays r2c and r2d shown in FIG. Through the aperture openings 41 and 42 of the aperture mask 40 and the re-imaging lens portions 51 and 52 of the re-imaging optical system 50, and images are formed on the light receiving element rows 61 and 62 of the CCD chip 60, respectively. . Similarly, the light beam passing through the field opening 23 passes through the lens portion 33 of the condenser lens 30 and the aperture openings 45 and 46 of the aperture mask 40 and the re-imaging optical system 50 as shown by chief rays r2e and r2f shown in FIG. Are imaged on the light receiving element arrays 65 and 66 of the CCD chip 66, respectively. The photographing lens in the focus detection area outside the optical axis corresponding to the field opening 21 by the pair of subject images on the light receiving element rows 61 and 62 and the field opening 23 by the pair of subject images on the light receiving element rows 65 and 66. The focus state is detected.
[0005]
In this way, focus detection of a plurality of focus detection areas has been made possible.
Japanese Patent Laid-Open No. 2-50115 discloses a focus detection device in which focus detection areas are arranged on a diagonal line of a shooting screen.
[0006]
[Problems to be solved by the invention]
As described above, when a plurality of focus detection areas are provided in the photographing screen, the aperture opening and the re-imaging lens unit for forming a pair of subject images on the light receiving element array are arranged in one focus detection area. Each pair is required. Further, in the focus detection area by the rectangular field opening 22 extending in the x-axis direction, focus detection cannot be performed on a subject having a luminance change in the x-axis direction, and the rectangular field extending in the y-axis direction. In the focus detection area by the openings 21 and 23, focus detection could not be performed on a subject having a luminance change in the y-axis direction.
[0007]
In Japanese Patent Laid-Open No. 2-50115, in order to increase the number of focus detection areas so that focus detection can be performed at more positions, focus detection areas are arranged on the diagonal line of the photographing screen. A pair of aperture openings and a pair of re-imaging lens portions are required for each focus detection region. In addition, in the focus detection area corresponding to the cross-shaped field opening, two pairs of aperture masks and re-imaging lens portions are required, which increases the size of the focus detection device and complicates the focus detection optical system itself. is there.
[0008]
The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and simplify the configuration of the focus detection optical system, despite having a large number of focus detection areas, and subjects that are not good at all focus detection areas It is an object of the present invention to provide a focus detection device capable of greatly reducing the above-mentioned.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the first aspect of the present invention provides a plurality of field openings (201) corresponding to the first and second focus detection areas and disposed in the vicinity of the planned imaging plane of the photographing lens (100). , 202) and a condenser lens having a plurality of lens portions (301, 302) for condensing light beams transmitted through the plurality of field openings (201, 202) of the field mask (200), respectively. 300) and a plurality of aperture openings (401, 402, 300) that divide the light beams transmitted through each of the plurality of field openings (201, 202) into a pair of light beams transmitted through different regions of the exit pupil of the photographing lens (100). 403, 404, 405, 406, 407, 408) and images of a plurality of field openings (201, 202) are formed on the light receiving means (600). In a focus detection apparatus having a re-imaging optical system (500) including a plurality of re-imaging lens units (501, 502, 503, 504, 505, 506, 507, 508) A focus detection area having a cross-shaped field opening (204) is further provided at a position different from the line connecting the centers of the detection areas, and one of the cross-shaped field openings (204) is transmitted through the rectangular field opening. The image that passes through the aperture opening (401, 404) and the re-imaging lens unit (501, 504) corresponding to the first focus detection area, and the image that passes through the other rectangular field opening is in the second focus detection area. Corresponding apertures (406, 408) and re-imaging lens portions (506, 508) are used.
[0010]
The invention of claim 2 is characterized in that all of the focus detection regions have a cross-shaped field opening.
The invention of claim 3 is characterized in that the cross-shaped field opening (204) has an inclined portion inclined with respect to the field opening (201, 202) corresponding to the first and second focus detection areas. .
According to the fourth aspect of the present invention, the first to third field openings (201, 201, 204) corresponding to the first to third focus detection areas set at different positions in the image plane by the photographing lens (100). ) And a field mask (200) provided on the image side of the photographic lens (100) with respect to the field mask (200), and the light flux that has passed through the first field opening (201) differs from the photographic lens (100). A first aperture pair (401, 402) that divides into a pair of light beams transmitted through the region and a light beam that passes through the second field opening (201) are divided into a pair of light beams that transmit through different regions of the photographing lens. An aperture mask (400) having a second aperture opening pair (403, 404) and an image side of the taking lens (100) from the aperture mask (400), and the first aperture aperture pair (401, 402). ) Therefore, the split image is divided by the first re-imaging lens pair (501, 502) that forms an image of the pair of light beams on the light receiving means (600) and the second aperture pair (403, 404). A re-imaging optical system (500) including a second re-imaging lens pair (503, 504) for forming an image of a pair of light beams on the light receiving means (600), and the light receiving means (600). The third through the one aperture (401) of the first aperture pair (401, 402) and the one lens (501) of the first re-imaging lens pair (501, 502). A first light receiving unit (615) that receives the light beam that has passed through the field aperture (204) of the first aperture, one aperture (404) of the second aperture pair (403, 404), and a second re-image. One lens (5 of the lens pair (503,504) It characterized in that it comprises a second light receiving portion for receiving the light beam and (616) passing through the 4) via a third field opening (204).
According to the fifth aspect of the present invention, the first field opening (201) and the second field opening (201) are provided so as to intersect each other, and the third field opening (204) is the first and second field openings ( 201, 201).
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view showing a schematic configuration of a focus detection apparatus according to the present invention, and FIG. 2 is a front view when a CCD chip is viewed from a subject side. The light flux from the object field forms an image near the field mask 200 through the photographing lens 100. The field mask 200 has a plurality of field openings 201, 202, 203, 204, 205, 206, and 207, the field opening 202 corresponds to the focus detection area at the center of the photographing screen, and the field openings 201 and 203 correspond to the photographing lens 100. Corresponding to the focus detection area at a position deviating from the optical axis L of the image, and the field openings 204, 205, 206, 207 are the centers of at least two focus detection areas among the focus detection areas corresponding to the field openings 201, 202, 203. Corresponds to a focus detection region at a position different from the line connecting the two. The condenser lens 300 has lens portions 301, 302, 303, 304, 305, 306, and 307.
[0012]
The image that passes through the field openings 201, 202, and 203 will be described in detail. Of the light flux from the object field, the light flux that passes through the rectangular opening extending in the x-axis direction of the field opening 202 is the lens of the condenser lens 300. The image is divided through the aperture 302 of the aperture mask 400 and the re-imaging lens units 505 and 506 of the re-imaging optical system 500 that are arranged at a position almost conjugate with the exit pupil of the photographing lens 100 via the unit 302. The images are formed on the light receiving element rows 605 and 606 of the CCD chip 600, respectively. A light beam passing through a rectangular opening extending in the y-axis direction of the field opening 202 passes through the lens portion 302 of the condenser lens 300, and the stop opening of the stop mask 400 disposed at a position almost conjugate with the exit pupil of the photographing lens 100. 407 and 408 and the re-imaging lens units 507 and 508 of the re-imaging optical system 500, and images are formed on the light receiving element rows 607 and 608 of the CCD chip 600, respectively.
[0013]
Of the light flux from the object scene, the light flux that passes through the rectangular opening extending in the x-axis direction of the field opening 201 is substantially conjugate with the exit pupil of the photographing lens 100 via the lens portion 301 of the condenser lens 300. The apertures 401 and 402 of the aperture mask 400 arranged at the positions and the re-imaging lens portions 501 and 502 of the re-imaging optical system 500 are divided and connected to the light receiving element rows 601 and 602 of the CCD chip 600, respectively. Image. A light beam passing through a rectangular opening extending in the y-axis direction of the field opening 201 passes through the lens portion 301 of the condenser lens 300, and the stop opening of the stop mask 400 disposed at a position almost conjugate with the exit pupil of the photographing lens 100. 403 and 404 and the re-imaging lens units 503 and 504 of the re-imaging optical system 500, and images are formed on the light receiving element rows 603 and 604 of the CCD chip 600, respectively.
[0014]
Further, out of the luminous flux from the object field, the luminous flux passing through the rectangular opening extending in the x-axis direction of the visual field opening 203 on the side opposite to the visual field opening 201 is passed through the lens unit 303 of the condenser lens 300 to take a photographing lens. The light is divided by the apertures 409 and 410 of the aperture mask 400 and the re-imaging lens units 509 and 510 of the re-imaging optical system 500, which are arranged at positions almost conjugate with the 100 exit pupils. An image is formed on the element rows 609 and 610. Light beams passing through the openings of the rectangle extending in the y-axis direction of the field aperture 20 3, through the lens portion 303 of the condenser lens 300, the diaphragm of the diaphragm mask 400 disposed on a position substantially conjugate with the exit pupil of the photographing lens 100 The light is divided through the apertures 411 and 412 and the re-imaging lens portions 511 and 512 of the re-imaging optical system 500, and forms images on the light receiving element rows 611 and 612 of the CCD chip 600, respectively.
[0015]
As described above, the focus detection areas corresponding to the field openings 201, 202, and 203 have two independent pairs of aperture openings 401, 402, 403, 404, 405, 406, respectively (because they are cross-shaped field openings). 407, 408, 409, 410, 411, 412 and re-imaging lens portions 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512 are used.
[0016]
The image transmitted through the field openings 204, 205, 206, and 207 will be described in detail. Of the light flux from the object field, a rectangular shape extending in the circumferential direction with respect to the optical axis L of the photographing lens 100 of the field opening 204 is described. The light beam passing through the aperture passes through the lens unit 304 of the condenser lens 300, and the aperture 406, which is the aperture corresponding to the field aperture 202 of the aperture mask 400 disposed at a position almost conjugate with the exit pupil of the photographing lens 100. 408 and the re-imaging lens units 506 and 508 which are re-imaging lens units corresponding to the field opening 202 of the re-imaging optical system 500, and are respectively connected to the light receiving element rows 623 and 624 of the CCD chip 600. Image. The light beam that passes through the rectangular opening extending in the radial direction with respect to the optical axis L of the photographing lens 100 in the field opening 204 passes through the lens unit 304 of the condenser lens 300 and is substantially conjugate with the exit pupil of the photographing lens 100. re corresponding to different viewing aperture 201 and the field opening 202 of the aperture stop 401,40 4 and the re-imaging optical system 500 is an aperture stop corresponding to different viewing aperture 201 and the field opening 202 of the deployed diaphragm mask 400 is split through the re-imaging lens unit 501,50 4 is an imaging lens unit, an image on light receiving element array 615, 616 of the CCD chip 600, respectively.
[0017]
Of the light flux from the object field, the light flux that passes through the rectangular opening extending in the circumferential direction with respect to the optical axis L of the photographing lens 100 in the field opening 205 passes through the lens portion 305 of the condenser lens 300. Aperture apertures 406 and 407 that are aperture apertures corresponding to the field aperture 202 of the aperture mask 400 arranged at a position almost conjugate with the exit pupil of the photographing lens 100 and a reconnection corresponding to the field aperture 202 of the re-imaging optical system 500. The images are divided through re-imaging lens portions 506 and 507 which are image lens portions, and form images on the light receiving element rows 621 and 622 of the CCD chip 600, respectively. The light beam passing through the rectangular opening extending in the radial direction with respect to the optical axis L of the photographing lens 100 at the field opening 205 passes through the lens portion 305 of the condenser lens 300 and is at a position substantially conjugate with the exit pupil of the photographing lens 100. The apertures 401 and 403, which are apertures corresponding to the field aperture 201 different from the field aperture 202 of the arranged aperture mask 400, and the reconnection corresponding to the field aperture 201 different from the field aperture 202 of the re-imaging optical system 500. The images are divided through re-imaging lens portions 501 and 503 which are image lens portions, and form images on the light receiving element rows 613 and 614 of the CCD chip 600, respectively.
[0018]
Further, of the light flux from the object field, the light flux passing through the rectangular opening extending in the circumferential direction with respect to the optical axis L of the photographing lens 100 in the field opening 206 passes through the lens portion 306 of the condenser lens 300, Aperture apertures 405 and 408 which are aperture apertures corresponding to the field aperture 202 of the aperture mask 400 disposed at a position substantially conjugate with the exit pupil of the photographing lens 100 and a reconnection corresponding to the field aperture 202 of the re-imaging optical system 500. The images are divided via re-imaging lens portions 505 and 508 which are image lens portions, and form images on light receiving element rows 619 and 620 of the CCD chip 600, respectively. The light beam that passes through the rectangular opening extending in the radial direction with respect to the optical axis L of the photographing lens 100 at the field opening 206 passes through the lens portion 306 of the condenser lens 300 and is substantially conjugate with the exit pupil of the photographing lens 100. The apertures 410 and 412 that are apertures corresponding to the field apertures 203 different from the field apertures 202 of the arranged aperture mask 400 and the reconnection corresponding to the field apertures 203 different from the field apertures 202 of the re-imaging optical system 500. The image is divided through re-imaging lens portions 510 and 512 which are image lens portions, and images are formed on the light receiving element rows 627 and 628 of the CCD chip 600, respectively.
[0019]
Furthermore, of the light flux from the object scene, the light flux that passes through the rectangular opening extending in the circumferential direction with respect to the optical axis L of the photographing lens 100 in the field opening 207 passes through the lens portion 307 of the condenser lens 300. Aperture apertures 405 and 407, which are aperture apertures corresponding to the field aperture 202 of the aperture mask 400 disposed at a position substantially conjugate with the exit pupil of the photographing lens 100, and a re-image corresponding to the field aperture 202 of the re-imaging optical system 500. The light is divided through re-imaging lens portions 505 and 507 which are imaging lens portions, and forms images on the light receiving element rows 617 and 618 of the CCD chip 600, respectively. The light beam passing through the rectangular opening extending in the radial direction with respect to the optical axis L of the photographing lens 100 at the field opening 207 passes through the lens portion 307 of the condenser lens 300 and is at a position almost conjugate with the exit pupil of the photographing lens 100. The apertures 410 and 411 which are apertures corresponding to the field aperture 203 different from the field aperture 203 of the arranged aperture mask 400 and the reconnection corresponding to the field aperture 203 different from the field aperture 202 of the re-imaging optical system 500. The image is divided through re-imaging lens portions 510 and 511 which are image lens portions, and images are formed on the light receiving element rows 625 and 626 of the CCD chip 600, respectively.
[0020]
As described above, the light beam passing through the field openings 204, 205, 206, and 207 uses the stop aperture and the re-imaging lens unit corresponding to the focus detection areas corresponding to the field openings 201, 202, and 203. In FIG. 2, the relationship between the field opening and the field opening image will be described. The field opening 201 is a field opening image 701, 702, 703, 704, the field opening 202 is a field opening image 705, 706, 707, 708, and the field opening 203 is a field opening image 709, 710, 711, 712. 204 the field aperture image 715,716,723,724, the field aperture 205 field opening image 7 13, 7 14,721,722, the field aperture 206 in field aperture image 719,720,727,728, field opening Reference numeral 207 corresponds to the field opening images 717, 718, 725, and 726, respectively.
[0021]
In the above configuration, for example, the aperture 405 of the aperture mask 400 and the lens portion 505 of the re-imaging lens 500 are shared by the field apertures 202, 206, and 207 of the field mask 200. In other words, the same stop aperture and re-imaging lens unit are used for light beams from different field apertures. Therefore, the configuration of the focus detection optical system can be greatly simplified.
[0022]
In addition, the aperture opening and the re-imaging lens unit of the focus detection area arranged at positions different from the line connecting the centers of at least two focus detection areas of the focus detection areas corresponding to the field openings 201, 202, and 203 are A diaphragm aperture and a reconnection corresponding to different field apertures among the field apertures 201, 202, and 203, which are a rectangle extending in the circumferential direction with respect to the optical axis L of the photographing lens 100 and a rectangle extending in the radial direction. Since the image lens unit is used, a cross-shaped focus detection area can be formed in all focus detection areas, and the number of subjects that are not good at focus detection can be greatly reduced.
[0023]
【The invention's effect】
As described above, according to the first aspect, the cross-shaped field opening is formed at a position different from the line connecting the centers of the first and second focus detection areas each using the unique aperture opening and the re-imaging lens unit. An image that has a focus detection region and that passes through one rectangular field aperture of the cross-shaped field aperture has a diaphragm aperture and a re-imaging lens unit corresponding to the first focus detection region, and the other rectangular aperture. Since the image transmitted through the field opening uses the stop aperture corresponding to the second focus detection area and the re-imaging lens unit, the components of the focus detection optical system can be greatly simplified.
[0024]
According to claim 2, in the focus detection apparatus according to claim 1, since all the focus detection areas have a cross-shaped field opening, focus detection can be performed without increasing the components of the focus detection optical system. It is possible to greatly reduce the subjects that are not good at.
According to claim 3, in the focus detection apparatus according to claim 1 or 2, the cross-shaped field opening has an inclined portion inclined with respect to the field opening corresponding to the first and second focus detection regions. As a result, the number of subjects that are not good at focus detection can be greatly reduced.
According to claim 4, the light receiving means passes through the third field opening through one of the first aperture pair and the one of the first re-imaging lens pair. A light beam that has passed through the third field opening via the first light receiving unit that receives the light beam, one of the second aperture pair and the second re-imaging lens pair. Since the second light receiving section for receiving the light is provided, the components of the focus detection optical system can be greatly simplified.
According to claim 5, in the focus detection apparatus according to claim 4, the first field opening and the second field opening are provided so as to intersect each other, and the third field opening is the first and second field openings. Since the camera is inclined with respect to the aperture, it is possible to greatly reduce the subjects that are not good at focus detection.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a focus detection apparatus of the present invention.
FIG. 2 is a front view showing a CCD chip in the focus detection apparatus of the present invention.
FIG. 3 is a perspective view showing a schematic configuration of a conventional focus detection apparatus.
4 is a schematic optical path diagram of the focus detection apparatus shown in FIG.
[Explanation of symbols]
20,200 Field masks 21 to 23, 201 to 207 Field openings 30,300 Condenser lenses 31 to 33, 301 to 307 Lens portions 40 and 400 of condenser lenses Aperture masks 41 to 46, 401 to 412 Aperture openings 50 of the aperture mask, 500 Re-imaging optical system 51-56, 501-512 Re-imaging lens unit 60,600 of re-imaging optical system CCD chips 61-66, 601-628 Light receiving element array 701-728 Field aperture image 90,900 Focus detection Device 100 Photo lens

Claims

撮影レンズの予定結像面近傍に配置されるとともに、第１および第２の焦点検出領域に対応した複数の視野開口を備える視野マスクと、
前記視野マスクの前記複数の視野開口を透過した光束をそれぞれ集光する複数のレンズ部を備えるコンデンサーレンズと、
前記複数の視野開口のそれぞれを透過した光束を、前記撮影レンズの射出瞳の異なる領域を透過した一対の光束に分割する複数の絞り開口を備える絞りマスクと、
前記複数の視野開口の像を受光手段上に結像させる複数の再結像レンズ部を備える再結像光学系とを有する焦点検出装置において、
前記第１と第２の焦点検出領域の中心を結ぶ線上とは異なる位置に、クロス状の視野開口を持つ焦点検出領域をさらに有し、
前記クロス状の視野開口のうちの一方の矩形の視野開口を透過する像は前記第１の焦点検出領域に対応した絞り開口と再結像レンズ部を、他方の矩形の視野開口を透過する像は前記第２の焦点検出領域に対応した絞り開口と再結像レンズ部を用いることを特徴とする焦点検出装置。A field mask that is disposed in the vicinity of the planned imaging plane of the photographic lens and includes a plurality of field openings corresponding to the first and second focus detection areas;
A condenser lens having a plurality of lens portions that respectively collect the light beams that have passed through the plurality of field openings of the field mask;
An aperture mask having a plurality of aperture openings that divides a light beam transmitted through each of the plurality of field openings into a pair of light beams transmitted through different regions of an exit pupil of the photographing lens;
In a focus detection apparatus having a re-imaging optical system including a plurality of re-imaging lens units for forming images of the plurality of field openings on a light receiving unit,
A focus detection region having a cross-shaped field opening at a position different from a line connecting the centers of the first and second focus detection regions;
An image that passes through one rectangular field opening of the cross-shaped field openings is an image that passes through the aperture opening and the re-imaging lens unit corresponding to the first focus detection region and the other rectangular field opening. Uses a stop aperture and a re-imaging lens unit corresponding to the second focus detection area.

前記焦点検出領域は、すべてクロス状の視野開口を持つことを特徴とする請求項１に記載の焦点検出装置。 The focus detection apparatus according to claim 1, wherein each of the focus detection areas has a cross-shaped field opening.

前記焦点検出装置は、前記クロス状の視野開口が前記第１および第２の焦点検出領域に対応した視野開口に対して傾斜した傾斜部を有することを特徴とする請求項１または２に記載の焦点検出装置。The said focus detection apparatus has the inclination part in which the said cross-shaped visual field opening incline with respect to the visual field opening corresponding to the said 1st and 2nd focus detection area | region. Focus detection device.

撮影レンズによる像面内の互いに異なる位置に設定された第１から第３の焦点検出領域に対応した第１から第３の視野開口を備える視野マスクと、A field mask comprising first to third field openings corresponding to first to third focus detection areas set at different positions in the image plane by the photographing lens;
前記視野マスクより前記撮影レンズの像側に配置され、前記第１の視野開口を通過した光束を前記撮影レンズの異なる領域を透過した一対の光束に分割する第１の絞り開口対と、前記第２の視野開口を通過した光束を前記撮影レンズの異なる領域を透過した一対の光束に分割する第２の絞り開口対とを備える絞りマスクと、A first aperture pair that is arranged on the image side of the photographic lens from the field mask and divides a light beam that has passed through the first field aperture into a pair of light beams that have passed through different areas of the photographic lens; A diaphragm mask comprising: a second diaphragm aperture pair that divides the light beam that has passed through the two field openings into a pair of light beams that have passed through different regions of the photographing lens;
前記絞りマスクより前記撮影レンズの像側に配置され、前記第１の絞り開口対によって分割された一対の光束による像を受光手段上に結像させる第１の再結像レンズ対と、前記第２の絞り開口対によって分割された一対の光束による像を前記受光手段上に結像させる第２の再結像レンズ対とを備える再結像光学系とを有し、A first re-imaging lens pair disposed on the image side of the photographic lens with respect to the aperture mask and forming an image of a pair of light beams divided by the first aperture pair on the light receiving means; A re-imaging optical system comprising a second re-imaging lens pair that forms an image of a pair of light beams divided by two aperture pairs on the light receiving means;
前記受光手段は、前記第１の絞り開口対のうちの一方の開口および前記第１の再結像レンズ対のうちの一方のレンズを介して前記第３の視野開口を通過した光束を受光する第１の受光部と、前記第２の絞り開口対のうちの一方の開口および前記第２の再結像レンズ対のうちの一方のレンズを介して前記第３の視野開口を通過した光束を受光する第２の受光部とを備えることを特徴とする焦点検出装置。The light receiving means receives the light beam that has passed through the third field opening through one of the first aperture pair and the one of the first re-imaging lens pair. A light beam that has passed through the third field opening through the first light receiving unit, one of the second aperture pair and the second re-imaging lens pair. And a second light receiving section for receiving light.

前記焦点検出装置は、前記第１の視野開口と前記第２の視野開口が互いに交差して設けられ、In the focus detection device, the first field opening and the second field opening are provided to intersect each other,
前記第３の視野開口が前記第１および第２の視野開口に対して傾斜していることを特徴とする請求項４に記載の焦点検出装置。The focus detection apparatus according to claim 4, wherein the third field opening is inclined with respect to the first and second field openings.