JP4869522B2 - Optical path bending zoom optical system - Google Patents

Description

ただし、ｒは近軸曲率半径、Ｋは円錐係数、A₄、A₆、A₈、A₁₀ はそれぞれ４次、６次、８次、１０次の非球面係数である。
【０１２７】

【０１２８】

【０１２９】

【０１３０】

【０１３１】

【０１３２】

【０１３３】

【０１３４】

【０１３５】

【０１３６】

【０１３７】
以上の実施例１の無限遠物点合焦時の収差図を図１１に示す。この収差図において、ＳＡは球面収差、ＡＳは非点収差、ＣＣは倍率色収差、ＤＴは歪曲収差を示す。図中、“ＦＩＹ”は像高を表す。
【０１３８】
次に、上記各実施例における条件（１）〜（５）に係わるｎｄ，ｆ_1G／√（ｆ_w ×ｆ_t ），Ｍ₃ ／Ｍ₂ ，−β_Rt，ＤＦＴ／ｆ_t の値を示す。

【０１３９】
以上の実施例１〜１０において、以下のｄ線の屈折率ｎ_d 、アッベ数ν_d を有するガラスの転移点Ｔｇは次の通りである。
【０１４０】

【０１４１】
また、上記各実施例において、以下のｄ線の屈折率ｎ_d 、アッベ数ν_d を有する媒体はプラスチックである。
【０１４２】

【０１４３】
なお、上記各実施例において、非球面を設けた光路折り曲げプリズムＰは全て、入射面に非球面を設けているが、射出面に非球面を設けるようにしてもよい。
【０１４４】
また、以上の実施例では全て、光学系の最も物体側の第１要素としてプリズムＰを用いているが、図１２に模式的に示すように、そのプリズムＰの前側（物体側）に単レンズ又は複数のレンズからなるレンズ群Ａを単数あるいは複数配置して、フォーカシングあるいはズーミングのために光軸に沿って移動させるようにしてもよい。
【０１４５】
さて、以上のような本発明の光路折り曲げズーム光学系は、ズームレンズ等の結像光学系で物体像を形成しその像をＣＣＤや銀塩フィルムといった撮像素子に受光させて撮影を行う撮影装置、とりわけデジタルカメラやビデオカメラ、情報処理装置の例であるパソコン、電話、携帯端末、特に持ち運びに便利な携帯電話等に用いることができる。以下に、その実施形態を例示する。
【０１４６】
図１３〜図１５は、本発明によるズーム光学系をデジタルカメラの撮影光学系４１に組み込んだ構成の概念図を示す。図１３はデジタルカメラ４０の外観を示す前方斜視図、図１４は同後方斜視図、図１５はデジタルカメラ４０の構成を示す断面図である。デジタルカメラ４０は、この例の場合、撮影用光路４２を有する撮影光学系４１、ファインダー用光路４４を有するファインダー光学系４３、シャッター４５、フラッシュ４６、液晶表示モニター４７等を含み、カメラ４０の上部に配置されたシャッター４５を押圧すると、それに連動して撮影光学系４１、例えば実施例５の光路折り曲げズーム光学系を通して撮影が行われる。撮影光学系４１によって形成された物体像が、平行平面板群Ｆ中の近赤外カットフィルターと光学的ローパスフィルターを介してＣＣＤ４９の撮像面上に形成される。このＣＣＤ４９で受光された物体像は、処理手段５１を介し、電子画像としてカメラ背面に設けられた液晶表示モニター４７に表示される。また、この処理手段５１には記録手段５２が接続され、撮影された電子画像を記録することもできる。なお、この記録手段５２は処理手段５１と別体に設けてもよいし、フロッピーディスクやメモリーカード、ＭＯ等により電子的に記録書込を行うように構成してもよい。また、ＣＣＤ４９に代わって銀塩フィルムを配置した銀塩カメラとして構成してもよい。
【０１４７】
さらに、ファインダー用光路４４上にはファインダー用対物光学系５３が配置してある。このファインダー用対物光学系５３によって形成された物体像は、像正立部材であるポロプリズム５５の視野枠５７上に形成される。このポリプリズム５５の後方には、正立正像にされた像を観察者眼球Ｅに導く接眼光学系５９が配置されている。なお、撮影光学系４１及びファインダー用対物光学系５３の入射側、接眼光学系５９の射出側にそれぞれカバー部材５０が配置されている。
【０１４８】
このように構成されたデジタルカメラ４０は、撮影光学系４１が広画角で高変倍比であり、収差が良好で、明るく、フィルター等が配置できるバックフォーカスの大きなズームレンズであるので、高性能・低コスト化が実現できる。
【０１４９】
なお、図１５の例では、カバー部材５０として平行平面板を配置しているが、パワーを持ったレンズを用いてもよい。
【０１５０】
次に、本発明のズーム光学系が対物光学系として内蔵された情報処理装置の一例であるパソコンが図１６〜図１８に示される。図１６はパソコン３００のカバーを開いた前方斜視図、図１７はパソコン３００の撮影光学系３０３の断面図、図１８は図１６の状態の側面図である。図１６〜図１８に示されるように、パソコン３００は、外部から繰作者が情報を入力するためのキーボード３０１と、図示を省略した情報処理手段や記録手段と、情報を操作者に表示するモニター３０２と、操作者自身や周辺の像を撮影するための撮影光学系３０３とを有している。ここで、モニター３０２は、図示しないバックライトにより背面から照明する透過型液晶表示素子や、前面からの光を反射して表示する反射型液晶表示素子や、ＣＲＴディスプレイ等であってよい。また、図中、撮影光学系３０３は、モニター３０２の右上に内蔵されているが、その場所に限らず、モニター３０２の周囲や、キーボード３０１の周囲のどこであってもよい。
【０１５１】
この撮影光学系３０３は、撮影光路３０４上に、本発明による光路折り曲げズーム光学系（図では略記）からなる対物レンズ１１２と、像を受光する撮像素子チップ１６２とを有している。これらはパソコン３００に内蔵されている。
【０１５２】
ここで、撮像素子チップ１６２上には光学的ローパスフィルターＬＦが付加的に貼り付けられて撮像ユニット１６０として一体に形成され、対物レンズ１１２の鏡枠１１３の後端にワンタッチで嵌め込まれて取り付け可能になっているため、対物レンズ１１２と撮像素子チップ１６２の中心合わせや面間隔の調整が不要であり、組立が簡単となっている。また、鏡枠１１３の先端（図示略）には、対物レンズ１１２を保護するためのカバーガラス１１４が配置されている。なお、鏡枠１１３中のズームレンズの駆動機構等は図示を省いてある。
【０１５３】
撮像素子チップ１６２で受光された物体像は、端子１６６を介して、パソコン３００の処理手段に入力され、電子画像としてモニター３０２に表示される、図１６には、その一例として、操作者の撮影された画像３０５が示されている。また、この画像３０５は、処理手段を介し、インターネットや電話を介して、遠隔地から通信相手のパソコンに表示されることも可能である。
【０１５４】
次に、本発明のズーム光学系が撮影光学系として内蔵された情報処理装置の一例である電話、特に持ち運びに便利な携帯電話が図１９に示される。図１９（ａ）は携帯電話４００の正面図、図１９（ｂ）は側面図、図１９（ｃ）は撮影光学系４０５の断面図である。図１９（ａ）〜（ｃ）に示されるように、携帯電話４００は、操作者の声を情報として入力するマイク部４０１と、通話相手の声を出力するスピーカ部４０２と、操作者が情報を入力する入力ダイアル４０３と、操作者自身や通話相手等の撮影像と電話番号等の情報を表示するモニター４０４と、撮影光学系４０５と、通信電波の送信と受信を行うアンテナ４０６と、画像情報や通信情報、入力信号等の処理を行う処理手段（図示せず）とを有している。ここで、モニター４０４は液晶表示素子である。また、図中、各構成の配置位置は、特にこれらに限られない。この撮影光学系４０５は、撮影光路４０７上に配置された本発明による光路折り曲げズーム光学系（図では略記）からなる対物レンズ１１２と、物体像を受光する撮像素子チップ１６２とを有している。これらは、携帯電話４００に内蔵されている。
【０１５５】
ここで、撮像素子チップ１６２上には光学的ローパスフィルターＬＦが付加的に貼り付けられて撮像ユニット１６０として一体に形成され、対物レンズ１１２の鏡枠１１３の後端にワンタッチで嵌め込まれて取り付け可能になっているため、対物レンズ１１２と撮像素子チップ１６２の中心合わせや面間隔の調整が不要であり、組立が簡単となっている。また、鏡枠１１３の先端（図示略）には、対物レンズ１１２を保護するためのカバーガラス１１４が配置されている。なお、鏡枠１１３中のズームレンズの駆動機構等は図示を省いてある。
【０１５６】
撮影素子チップ１６２で受光された物体像は、端子１６６を介して、図示していない処理手段に入力され、電子画像としてモニター４０４に、又は、通信相手のモニターに、又は、両方に表示される。また、通信相手に画像を送信する場合、撮像素子チップ１６２で受光された物体像の情報を、送信可能な信号へと変換する信号処理機能が処理手段には含まれている。
【０１５７】
以上の本発明の光路折り曲げズーム光学系及びそれを用いた装置は例えば次のように構成することができる。
【０１５８】
〔１〕 少なくとも、物体側から順に、負の屈折力を有する第１レンズ群、正の屈折力を有する第２レンズ群、それ以降の少なくとも１つのレンズ群からなっていて、広角端から望遠端に変倍する際に、前記第２レンズ群を含んで光軸に沿って移動する少なくとも１つのレンズ群を含むズーム光学系において、
前記第１レンズ群が、光路を折り曲げるための少なくとも１面の反射面と、入射面と、射出面とを含むプリズムを有し、前記プリズムの入射面、射出面の少なくとも一方は光軸に回転対称な曲面であることを特徴とする光路折り曲げズーム光学系。
【０１５９】
〔２〕 少なくとも、物体側から順に、負の屈折力を有し、少なくとも負の屈折力のプリズムを１つ含む第１レンズ群、正の屈折力を有する第２レンズ群、それ以降の少なくとも１つのレンズ群からなっていて、広角端から望遠端に変倍する際に、前記第２レンズ群を含んで光軸に沿って移動する少なくとも１つのレンズ群を含むズーム光学系において、
前記プリズムは、光路を折り曲げるための少なくとも１面の反射面と、入射面と、射出面とを含み、かつ、前記入射面、射出面の少なくとも一方は曲面であることを特徴とする光路折り曲げズーム光学系。
【０１６０】
〔３〕 少なくとも、物体側から順に、負の屈折力を有する第１レンズ群、正の屈折力を有する第２レンズ群、それ以降の少なくとも１つのレンズ群からなっていて、広角端から望遠端に変倍する際に、前記第２レンズ群を含んで光軸に沿って移動する少なくとも１つのレンズ群を含むズーム光学系において、
前記第１レンズ群が、光路を折り曲げるための少なくとも１面の反射面と、入射面と、射出面とを含むプリズムを有し、前記プリズムの入射面、射出面の少なくとも一方は曲面であり、前記プリズムのｄ線における屈折率ｎｄが以下の条件式（１）を満たすことを特徴とする光路折り曲げズーム光学系。
【０１６１】
１．６＜ｎｄ＜２．０ ・・・（１）
〔４〕 上記１から３の何れか１項において、以下の条件式（２）を満たすことを特徴とする光路折り曲げズーム光学系。
【０１６２】
−５．０＜ｆ_1G／√（ｆ_w ×ｆ_t ）＜−０．３ ・・・（２）
ただし、ｆ_1Gは第１レンズ群の焦点距離、ｆ_w は広角端での無限遠物点合焦時の全系の焦点距離、ｆ_t は望遠端での無限遠物点合焦時の全系の焦点距離である。
【０１６３】
〔５〕 上記１から３の何れか１項において、前記第２レンズ群の後に、正の屈折力を有する第３レンズ群を含み、広角端から望遠端に変倍する際に、前記第２レンズ群と前記第３レンズ群が相対的間隔を変えながら光軸に沿って移動することを特徴とする光路折り曲げズーム光学系。
【０１６４】
〔６〕 上記５において、無限遠合焦時に広角端から望遠端に変倍する際の前記第２レンズ群、前記第３レンズ群のそれぞれの移動量をＭ₂ 、Ｍ₃ とすると、以下の条件式（３）を満足することを特徴とする光路折り曲げズーム光学系。
【０１６５】
０．３＜Ｍ₃ ／Ｍ₂ ＜３．０ ・・・（３）
〔７〕 上記５において、望遠端における第２レンズ群以降の合成系の倍率β_Rtが、以下の条件式（４）を満足することを特徴とする光路折り曲げズーム光学系。
【０１６６】
１．０＜−β_Rt＜２．３ ・・・（４）
〔８〕 上記１から３の何れか１項において、最も像側のレンズ群に非球面を少なくとも１面有することを特徴とする光路折り曲げズーム光学系。
【０１６７】
〔９〕 上記８において、変倍時及び合焦時に、最も像側のレンズ群は固定であることを特徴とする光路折り曲げズーム光学系。
【０１６８】
〔１０〕 上記９において、像側から２番目のレンズ群を光軸方向に移動して合焦することを特徴とする光路折り曲げズーム光学系。
【０１６９】
〔１１〕 上記１から３の何れか１項において、前記第１レンズ群に非球面を少なくとも１面有することを特徴とする光路折り曲げズーム光学系。
【０１７０】
〔１２〕 上記１１において、変倍時及び合焦時に、前記第１レンズ群は固定であることを特徴とする光路折り曲げズーム光学系。
【０１７１】
〔１３〕 上記１から３の何れか１項において、前記プリズムより像側に配置されたレンズ群、又は、前記プリズムより像側に配置されたレンズ群中の一部のレンズを光軸方向に移動することで合焦することを特徴とする光路折り曲げズーム光学系。
【０１７２】
〔１４〕 上記１０において、像側から２番目のレンズ群と３番目のレンズ群の望遠端での無限遠物点合焦時の光軸上空気間隔ＤＦＴが以下の条件式（５）を満足することを特徴とする光路折り曲げズーム光学系。
【０１７３】
０．０１＜ＤＦＴ／ｆ_t ＜２．０ ・・・（５）
ただし、ｆ_t は望遠端での無限遠物点合焦時の全系の焦点距離である。
【０１７４】
〔１５〕 上記５において、前記第１レンズ群が、負の屈折力を有する１つのプリズムと、１枚の負レンズと、１枚の正レンズからなり、前記第３レンズ群が１枚の正レンズからなることを特徴とする光路折り曲げズーム光学系。
【０１７５】
〔１６〕 上記５において、前記第１レンズ群が、負の屈折力を有する１つのプリズムと、１枚の正レンズからなり、前記第３レンズ群が、１枚の正レンズと、１枚の負レンズからなることを特徴とする光路折り曲げズーム光学系。
【０１７６】
〔１７〕 上記１５又は１６において、前記第３レンズ群を光軸方向に移動することにより合焦することを特徴とする光路折り曲げズーム光学系。
【０１７７】
〔１８〕 上記１１において、前記プリズムの入射面、射出面の少なくとも一方が非球面であることを特徴とする光路折り曲げズーム光学系。
【０１７８】
〔１９〕 上記８又は１１において、非球面が形成されたレンズあるいはプリズムがガラスからなり、その転移点Ｔｇが以下の条件式（６）を満たすことを特徴とする光路折り曲げズーム光学系。
【０１７９】
６０℃＜Ｔｇ＜６２０℃ ・・・（６）
〔２０〕 上記８又は１１において、非球面が形成されたレンズあるいはプリズムが、ガラス成形法で加工されたことを特徴とする光路折り曲げズーム光学系。
【０１８０】
〔２１〕 上記８又は１１において、非球面が形成されたレンズあるいはプリズムが、有機無機ハイブリッド材料からなることを特徴とする光路折り曲げズーム光学系。
【０１８１】
〔２２〕 上記８又は１１において、非球面が形成されたレンズあるいはプリズムが、プラスチックからなることを特徴とする光路折り曲げズーム光学系。
【０１８２】
〔２３〕 上記１から３の何れか１項において、プリズムがプラスチックからなることを特徴とする光路折り曲げズーム光学系。
【０１８３】
〔２４〕 上記１から３の何れか１項において、全てのレンズ及びプリズムがプラスチックからなることを特徴とする光路折り曲げズーム光学系。
【０１８４】
〔２５〕 上記１から３の何れか１項において、光軸の折り曲げ面が像面に配置される撮像素子の撮像面の短辺に平行になるように光軸を折り曲げていることを特徴とする光路折り曲げズーム光学系。
【０１８５】
〔２６〕 上記１から３の何れか１項において、前記プリズムは、変倍時に可動な全てのレンズ群の最も物体側のレンズよりも物体側に配置されていることを特徴とする光路折り曲げズーム光学系。
【０１８６】
〔２７〕 上記１から３の何れか１項において、変倍時に移動するレンズ群は、広角端から望遠端に変倍する際に、単調に物体側に移動することを特徴とする光路折り曲げズーム光学系。
【０１８７】
〔２８〕 上記１から３の何れか１項において、前記プリズムより像側の光路上に少なくとも１つの開口絞りを配置したことを特徴とする光路折り曲げズーム光学系。
【０１８８】
〔２９〕 上記５において、前記第３レンズ群を光軸方向に移動して合焦することを特徴とする光路折り曲げズーム光学系。
【０１８９】
〔３０〕 上記１から２９の何れか１項記載の光路折り曲げズーム光学系と、前記光路折り曲げズーム光学系によって形成された物体像を受光する位置に配置された電子撮像素子と、前記電子撮像素子によって光電変換された電子信号を処理する処理手段と、操作者が前記処理手段に入力したい情報信号を入力するための入力部と、前記処理手段からの出力を表示する表示素子と、前記処理手段からの出力を記録する記録媒体とを含み、
前記処理手段は、前記光路折り曲げズーム光学系によって前記電子撮像素子に受光された物体像を前記表示素子に表示するように構成されていることを特徴とする情報処理装置。
【０１９０】
〔３１〕 上記３０において、
前記入力部がキーボードにて構成され、前記光路折り曲げズーム光学系と前記電子撮像素子とが前記表示素子の周辺部又は前記キーボードの周辺部に内蔵されていることを特徴とするパソコン装置。
【０１９１】
〔３２〕 上記１から２９の何れか１項記載の光路折り曲げズーム光学系と、前記光路折り曲げズーム光学系によって形成された物体像を受光する位置に配置された電子撮像素子と、電話信号を送信及び受信するためのアンテナと、電話番号等の信号を入力するための入力部と、前記電子撮像素子によって受光された物体像を送信可能な信号に変換する信号処理部とを含んでいることを特徴とする電話装置。
【０１９２】
〔３３〕 上記１から２９の何れか１項記載の光路折り曲げズーム光学系と、前記光路折り曲げズーム光学系によって形成された物体像を受光する位置に配置された電子撮像素子と、前記電子撮像素子によって光電変換された電子信号を処理する処理手段と、前記電子撮像素子で受光された物体像を観察可能に表示する表示素子とを有し、前記電子撮像素子で受光された物体像の像情報を記録するための記録部材を内蔵又は挿脱するように構成され、前記処理手段が、前記電子撮像素子に受光された物体像を前記表示素子に表示する表示処理機能と、前記電子撮像素子に受光された物体像を前記記録媒体に記録する記録処理機能とを有することを特徴とする電子カメラ装置。
【０１９３】
【発明の効果】
以上の説明から明らかなように、本発明によると、小型デジタルスチルカメラ、携帯端末等に搭載可能な薄型ズーム光学系であって、薄型化のため光軸を曲げ、かつ、折り曲げプリズムにパワーを持たせた光路折り曲げズーム光学系を提供することができる。
【図面の簡単な説明】
【図１】本発明の光路折り曲げズーム光学系の実施例１の無限遠物点合焦時の広角端（ａ）、中間状態（ｂ）、望遠端（ｃ）でのレンズ断面図である。
【図２】実施例２の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図３】実施例３の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図４】実施例４の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図５】実施例５の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図６】実施例６の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図７】実施例７の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図８】実施例８の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図９】実施例９の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図１０】実施例１０の光路折り曲げズーム光学系の図１と同様のレンズ断面図である。
【図１１】実施例１の無限遠物点合焦時の収差図である。
【図１２】本発明の光路折り曲げズーム光学系の変形例の構成を模式的に示す図である。
【図１３】本発明による光路折り曲げズーム光学系を組み込んだデジタルカメラの外観を示す前方斜視図である。
【図１４】図１３のデジタルカメラの後方斜視図である。
【図１５】図１３のデジタルカメラの断面図である。
【図１６】本発明による光路折り曲げズーム光学系を対物光学系として組み込れたパソコンのカバーを開いた前方斜視図である。
【図１７】パソコンの撮影光学系の断面図である。
【図１８】図１６の状態の側面図である。
【図１９】本発明による光路折り曲げズーム光学系を対物光学系として組み込れた携帯電話の正面図、側面図、その撮影光学系の断面図である。
【符号の説明】
Ｇ１…第１レンズ群
Ｇ２…第２レンズ群
Ｇ３…第３レンズ群
Ｇ４…第４レンズ群
Ｐ…光路折り曲げプリズム
Ｓ…開口絞り（独立の場合）
Ｆ…平行平面板群
Ｉ…像面
Ａ…フォーカシングレンズ群又はズーミングレンズ群
Ｅ…観察者眼球
ＬＦ…光学的ローパスフィルター
４０…デジタルカメラ
４１…撮影光学系
４２…撮影用光路
４３…ファインダー光学系
４４…ファインダー用光路
４５…シャッター
４６…フラッシュ
４７…液晶表示モニター
４９…ＣＣＤ
５０…カバー部材
５１…処理手段
５２…記録手段
５３…ファインダー用対物光学系
５５…ポロプリズム
５７…視野枠
５９…接眼光学系
１１２…対物レンズ
１１３…鏡枠
１１４…カバーガラス
１６０…撮像ユニット
１６２…撮像素子チップ
１６６…端子
３００…パソコン
３０１…キーボード
３０２…モニター
３０３…撮影光学系
３０４…撮影光路
３０５…画像
４００…携帯電話
４０１…マイク部
４０２…スピーカ部
４０３…入力ダイアル
４０４…モニター
４０５…撮影光学系
４０６…アンテナ
４０７…撮影光路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical path bending zoom optical system, and more particularly, to a zoom optical system in which an optical path bending prism is disposed in order to achieve a reduction in the depth direction of a digital camera, a portable terminal, or the like equipped with the zoom optical system.
[0002]
[Prior art]
There is a strong demand for miniaturization, particularly thinning, in compact cameras using electronic imaging elements such as CCDs and imaging optical systems built into portable terminals, cellular phones and the like.
[0003]
Under such circumstances, Japanese Patent Application Laid-Open No. 10-20191 discloses that a triangular prism having a plano-convex lens joined between groups of a four-group zoom lens is disposed to bend the optical path for compactification.
[0004]
Further, although not a zoom lens, Japanese Patent Application Laid-Open Nos. 9-2111287 and 10-239594 are known as power (refractive power, divergent power) applied to an optical path bending prism of an optical path bending optical system. It has been.
[0005]
[Problems to be solved by the invention]
However, in the case of Japanese Patent Laid-Open No. 10-20191, since the prism is disposed after the stop, it is difficult to reduce the thickness.
[0006]
In addition, as described above, Japanese Patent Application Laid-Open Nos. 9-2111287 and 10-239594 that give power to the prism are not zoom lenses, and are also used as prisms from the viewpoint of miniaturization and thinning of the optical system. It is not something that has power.
[0007]
The present invention has been made in view of such a situation in the prior art, and an object thereof is a thin zoom optical system that can be mounted on a small digital still camera, a portable terminal, etc. An optical path bending zoom optical system in which power is applied to a bending and bending prism.
[0008]
[Means for Solving the Problems]
  The first optical path bending zoom optical system of the present invention that achieves the above object is
  The zoom lens includes at least a first lens group having a negative refractive power, a second lens group having a positive refractive power, and at least one subsequent lens group in order from the object side, and zooming from the wide-angle end to the telephoto end. In the zoom optical system including at least one lens unit that moves along the optical axis including the second lens unit,
  The first lens group for bending the optical path;One sideThe prism includes a reflecting surface, an incident surface, and an exit surface, and at least one of the entrance surface and the exit surface of the prism is a curved surface that is rotationally symmetric with respect to the optical axis.The
  The zoom optical system has only one reflecting surface.It is characterized by that.
[0009]
  The second optical path bending zoom optical system of the present invention is
  A first lens group having at least one prism having negative refractive power and at least one negative refractive power in order from the object side, a second lens group having positive refractive power, and at least one lens group thereafter A zoom optical system including at least one lens unit including the second lens unit and moving along the optical axis when zooming from the wide-angle end to the telephoto end.
  The prism is used to bend the optical path.One sideA reflecting surface, an incident surface, and an exit surface, and at least one of the entrance surface and the exit surface is a curved surface.The
  The zoom optical system has only one reflecting surface.An optical path bending zoom optical system.
[0010]
  The third optical path bending zoom optical system of the present invention is
  The zoom lens includes at least a first lens group having a negative refractive power, a second lens group having a positive refractive power, and at least one subsequent lens group in order from the object side, and zooming from the wide-angle end to the telephoto end. In the zoom optical system including at least one lens unit that moves along the optical axis including the second lens unit,
  The first lens group for bending the optical path;One sideThe prism includes a reflecting surface, an incident surface, and an exit surface. At least one of the entrance surface and the exit surface of the prism is a curved surface, and the refractive index nd at the d-line of the prism is the following conditional expression ( Meet 1)And
  The zoom optical system has only one reflecting surface.It is characterized by that.
    1.6 <nd <2.0 (1)
[0011]
1.6 <nd <2.0 (1)
Below, the reason and effect | action which take the said structure in this invention are demonstrated.
[0012]
At least in order from the object side, the first lens group, the second lens group, and at least one subsequent lens group, and including the second lens group when zooming from the wide-angle end to the telephoto end In a zoom lens that moves along an axis, if the refractive power of the first lens group is negative, the light beam height after the second lens group can be kept low, and the thickness of the optical system can be reduced. Therefore, in the zoom optical system of the present invention, the first lens group has a negative refractive power, and the second lens group has a positive refractive power accordingly.
[0013]
In order to make the lens incident surface face the object side and reduce the depth, the optical path should be bent at the object side position of the optical system as much as possible. When the lens entrance surface is directed toward the object side, the optical system is in the depth direction from the lens entrance surface to the optical path bending position. Therefore, when the prism that bends the optical path is arranged as far as possible on the object side, that is, in the first lens group, The depth direction can be made thinner.
[0014]
Compared with the case where a mirror is used for bending the optical path, when the optical path is bent with a prism, light passes through a medium having a refractive index greater than 1, so that the air equivalent length becomes longer even with the same optical path length. Therefore, when the optical path is bent by the prism, the total length of the optical system can be shortened, and the optical system can be further downsized.
[0015]
In addition, if at least one of the incident surface and the reflecting surface of the prism is a curved surface, for example, a curved surface that is rotationally symmetric with respect to the optical axis, the prism itself can have a refractive power, so the number of lenses other than the prism can be reduced. The system can be made smaller. In addition, the aberration can be further reduced by using the same number of lenses.
[0016]
If the refractive power of the prism is negative, the height of the light beam on the image side of the prism can be lowered, and the thickness of the optical system can be made thinner. Furthermore, if the refractive power of the prism is negative, the refractive power of the first lens group having a negative refractive power including the prism can be shared. Therefore, the number of constituent lenses of the first lens group is reduced, leading to miniaturization of the optical system.
[0017]
When the refractive index nd of the prism exceeds the lower limit of 1.6 of the conditional expression (1), the refractive power of the prism becomes small, and aberrations are effectively corrected, and the beam height after the prism is kept low. Can not do. The refractive power can be increased by increasing the curvature of the curved surface of the incident surface or exit surface of the prism. However, as the curvature is increased, the eccentricity sensitivity of the prism increases and the performance tends to deteriorate. If the upper limit of 2.0 in conditional expression (1) is exceeded, the dispersion of the medium increases and the chromatic aberration increases.
[0018]
In the above, it is desirable to satisfy the following conditional expression (2).
[0019]
−5.0 <f_1G/ √ (f_w× f_t) <− 0.3 (2)
Where f_1GIs the focal length of the first lens group, f_wIs the focal length of the entire system when focusing on an object point at infinity at the wide-angle end, f_tIs the focal length of the entire system when focusing on an object point at infinity at the telephoto end.
[0020]
  Conditional expression (2)
  −5.0 <f _1G / √ (f _w × f _t ) ≦ −0.9674 (2 ′)
It is preferable to satisfy.
  Conditional expression (2)
  −5.0 <f_1G/ √ (f_w × f_t ) ≦ −0.3 (2-1)
It is preferable to satisfy.
[0021]
further,
-1.7 <f_1G/ √ (f_w× f_t<-0.8 (2-2)
It is more desirable to satisfy.
[0022]
In order to reduce the thickness of the optical system while keeping the decentration sensitivity after the first lens group and the second lens group low, conditional expression (2) should be satisfied. If the upper limit of -0.3 in conditional expression (2) is exceeded, the refractive power of the first lens group will be too small, and the light beam height after the second lens group will become high, so that the second lens group will be increased. Subsequent eccentricity sensitivity becomes high. In addition, the optical system becomes thick. If the lower limit of −5.0 in conditional expression (2) is exceeded, the refractive power of the first lens group will be too great, and the decentering sensitivity of the first lens group will be high.
[0023]
Furthermore, when the conditional expression (2-1) is satisfied, it is more preferable that the optical system can be thinned while lowering the decentration sensitivity after the first lens group and the second lens group.
[0024]
Furthermore, when the conditional expression (2-2) is satisfied, the optical system can be made thinner while further reducing the decentration sensitivity after the first lens group and the second lens group, which is more preferable.
[0025]
The second lens group includes a third lens group having a positive refractive power after the second lens group, and the second lens group and the third lens group change relative distances when zooming from the wide angle end to the telephoto end. It is desirable to move along the optical axis.
[0026]
That is, when zooming from the wide-angle end to the telephoto end, the zoom method in which the second lens group having a positive refractive power and the third lens group having a positive refractive power move while changing the relative distance is: High magnification can be obtained while using the space efficiently and correcting the focal position by zooming.
[0027]
In this case, the amount of movement of each of the second lens group and the third lens group at the time of zooming from the wide-angle end to the telephoto end when focusing on infinity is set to₂, M_ThreeThen, it is desirable to satisfy the following conditional expression (3).
[0028]
    0.3 <M_Three / M₂ <3.0 (3)
  Conditional expression (3) further
    0.5 <M_Three / M₂ <2.0 (3-1)
It is preferable to satisfy.
  Conditional expression (3) further
    0.802 ≦ M _Three / M ₂ <3.0 (3 ')
It is preferable to satisfy.
[0029]
further,
0.7 <M_Three/ M₂<1.7 (3-2)
It is more desirable to satisfy.
[0030]
Ratio M of the movement amount of the second lens group and the third lens group_Three/ M₂However, if the upper limit of 3.0 of conditional expression (3) is exceeded, the third lens group will move very much, and the distance between the second lens group and the third lens group will be too small at the telephoto end. In this case, the third lens group cannot secure a space that can be extended for focusing, and a sufficient focus distance range cannot be secured. Also, if the focusable distance range is secured, a sufficient zoom ratio cannot be secured. M_Three/ M₂However, if the lower limit of 0.3 of conditional expression (3) is exceeded, the third lens group will not move much, and a sufficient zoom ratio cannot be secured. Therefore, M_Three/ M₂Preferably satisfies the conditional expression (3).
[0031]
Further, it is more preferable to satisfy the conditional expression (3-1) because the zoom ratio and the focusable distance range can be secured.
[0032]
Furthermore, it is more preferable to satisfy the conditional expression (3-2) because a zoom ratio and a focusable distance range can be further secured.
[0033]
Further, the magnification β of the composite system after the second lens unit at the telephoto end_RtHowever, it is desirable that the following conditional expression (4) is satisfied.
[0034]
1.0 <−β_Rt<2.3 (4)
Conditional expression (4)
1.0 <−β_Rt<2.1 (4-1)
It is desirable to satisfy.
[0035]
further,
    1.0 <−β_Rt<1.9 (4-2)
It is more desirable to satisfy.
  Conditional expression (4)
    1.0 <−β _Rt ≦ 1.586 (4 ')
It is more desirable to satisfy.
[0036]
To keep the relative distance between the second lens group and the third lens group as small as possible, the absolute value of the magnification of the synthesis system after the second lens group should be larger than 1 and scaled as close to 1 times as possible. It is good. In other words, the combination magnification at the time of focusing on an object point at infinity at the telephoto end after the second lens group is β_RtThen, it is desirable to satisfy conditional expression (4). If the upper limit of 2.3 and the lower limit of 1.0 in the conditional expression (4) are exceeded, the amount of change in the relative distance between the second lens group and the third lens group becomes large.
[0037]
Furthermore, when the conditional expression (4-1) is satisfied, the relative distance change between the second lens group and the third lens group can be kept smaller.
[0038]
Further, when the conditional expression (4-2) is satisfied, the change in the relative distance between the second lens group and the third lens group can be further reduced.
[0039]
  Further, it is desirable that one reflecting surface in the optical path bending zoom optical system of the present invention is a flat surface.
  In the optical path bending zoom optical system of the present invention, it is desirable that the lens group closest to the image side has at least one aspheric surface.
[0040]
The maximum ray height is high in the lens group closest to the image side. For this reason, when at least one aspherical surface is arranged in the lens group closest to the image side, it is possible to effectively correct off-axis aberrations such as distortion, astigmatism, and coma.
[0041]
In this case, it is desirable that the lens group closest to the image side is fixed at the time of zooming and focusing.
[0042]
The lens group closest to the image side has an aspherical surface, and aberrations generated on the object side from the aspherical surface, particularly off-axis aberrations, are canceled, and the lens group closest to the image side in the optical axis direction by zooming or focusing. If you move, the aberration balance will be lost. Therefore, it is better to fix the lens group closest to the image side.
[0043]
In that case, it is desirable to move the second lens group from the image side in the optical axis direction so as to be focused.
[0044]
When focusing is performed using the second lens group from the image side, there is little variation in focal length and aberration due to focusing, and focusing can be performed without degrading performance.
[0045]
In the optical path bending zoom optical system of the present invention, it is desirable that the first lens group has at least one aspheric surface.
[0046]
In the first lens group, the height of the light beam is high, and if it consists only of a spherical surface, the off-axis aberration cannot be suppressed. By disposing at least one aspheric surface in the first lens group, it is possible to effectively correct off-axis aberrations.
[0047]
In this case, it is desirable that the first lens group is fixed at the time of zooming and focusing.
[0048]
The first lens group has an aspherical surface, and aberrations generated on the object side from the aspherical surface, particularly off-axis aberrations, are canceled. If the lens is moved in the optical axis direction by zooming or focusing, the aberration balance is lost. End up. Therefore, it is better to fix the first lens group.
[0049]
Further, in the optical path bending zoom optical system according to the present invention, the lens group disposed on the image side from the prism or a part of the lens group disposed on the image side from the prism is moved in the optical axis direction. It is desirable to focus.
[0050]
Since the prism is a bending system, the mechanism becomes complicated if it is moved in the optical axis direction by zooming or focusing. Further, if the lens group on the object side of the prism or a part of the lenses in the lens group is moved, the thickness of the optical system changes and it is difficult to reduce the thickness. Therefore, it is preferable to focus by moving the lens group arranged on the image side of the prism or a part of the lenses in the lens group.
[0051]
In addition, when the second lens unit from the image side is moved in the optical axis direction and focused, the infinite object point is focused at the telephoto end of the second lens unit and the third lens unit from the image side. It is desirable that the air space DFT on the optical axis satisfies the following conditional expression (5).
[0052]
0.01 <DFT / f_t<2.0 (5)
Where f_tIs the focal length of the entire system when focusing on an object point at infinity at the telephoto end.
[0053]
Conditional expression (5)
0.03 <DFT / f_t<1.5 (5-1)
It is desirable to satisfy.
[0054]
further,
0.05 <DFT / f_t<1.0 (5-2)
It is more desirable to satisfy.
[0055]
If the focus position is changed to a closer distance side after focusing on an object point at infinity at the telephoto end, the second lens group from the image side to be focused is extended to the object side. At this time, if the air space DFT on the optical axis of the second lens group and the third lens group from the image side is too small, that is, if the lower limit value 0.01 of the conditional expression (5) is exceeded, the object is in focus. The space that can be extended to the side becomes narrow, and the focusable distance range cannot be taken sufficiently. On the other hand, if the upper limit of 2.0 in conditional expression (5) is exceeded, the distance between the second and third lens units from the image side can hardly be reduced at the time of zooming, and it is difficult to ensure the zoom ratio. . Therefore, DFT should satisfy conditional expression (5).
[0056]
Moreover, it is more preferable to satisfy the conditional expression (5-1) because a more focusable distance range can be secured and a zoom ratio can be secured.
[0057]
Furthermore, it is more preferable to satisfy the conditional expression (5-2) because a focusable distance range can be secured and a zoom ratio can be secured.
[0058]
When the third lens group having a positive refractive power is included, the first lens group includes one prism having a negative refractive power, one negative lens, and one positive lens. It is desirable that the three lens groups consist of one positive lens.
[0059]
Since the first lens group includes one prism having negative refractive power and one negative lens, the refractive power of the entire first lens group can be increased without increasing the refractive power of the prism and lens. Can do. In addition, when the first lens group has a negative refractive power and the negative refractive power increases, the maximum ray height after the second lens group can be kept low, the size of the lens can be reduced, and the optical system Can be made thinner. In addition, the decentration sensitivity after the second lens group can be kept low.
[0060]
In addition, when the third lens group having a positive refractive power is included, the first lens group includes one prism having a negative refractive power and one positive lens, and the third lens group includes one lens. It is desirable to consist of a positive lens and one negative lens.
[0061]
Since the first lens group is composed of one prism having negative refractive power and one positive lens, it is possible to reduce the number of lenses having a high maximum beam height and a large lens size, which leads to weight reduction of the entire optical system. . In addition, since the third lens group includes one positive lens and one negative lens, the refractive power of the entire third lens group can be increased without increasing the refractive power of each lens. Therefore, the amount of movement of the third lens group during zooming and focusing can be kept small, and the zoom ratio and the focusable distance range can be taken more sufficiently.
[0062]
In the above, it is desirable to focus by moving the third lens group in the optical axis direction.
[0063]
The third lens group is composed of one positive lens or one positive lens and one negative lens, and the third lens group has a small number of lenses and is light in weight. Therefore, when the third lens group is moved and focused, the power consumption required for the movement can be reduced.
[0064]
In the above, when the first lens group has an aspheric surface, at least one of the entrance surface and the exit surface of the prism may be an aspheric surface.
[0065]
The prism has a high light beam height, and if at least one of the entrance surface and the exit surface is aspheric, it is possible to effectively correct off-axis aberrations such as distortion, astigmatism, and coma.
[0066]
In the above, when the first lens group or the lens group closest to the image side has an aspherical surface, the lens or prism on which the aspherical surface is formed is made of glass, and the transition point Tg satisfies the following conditional expression (6). Is desirable.
[0067]
60 ° C <Tg <620 ° C (6)
The aspherical shape cannot be accurately obtained by polishing, and it is difficult to process a large amount by grinding. If the lens or prism on which the aspherical surface is formed is made of glass that satisfies the conditional expression (6), it can be processed by a glass forming method and can be easily produced in large quantities. Therefore, the optical system becomes inexpensive.
[0068]
When the first lens group or the lens group closest to the image side has an aspheric surface, it is desirable that the lens or prism on which the aspheric surface is formed is processed by a glass molding method.
[0069]
The aspherical shape cannot be accurately obtained by polishing, and it is difficult to process a large amount by grinding. If a lens or prism on which an aspherical surface is formed is processed by a glass molding method, it can be easily produced in large quantities, and the optical system becomes inexpensive.
[0070]
When the first lens group or the lens group closest to the image side has an aspheric surface, the lens or prism on which the aspheric surface is formed can be made of an organic-inorganic hybrid material.
[0071]
An organic-inorganic hybrid material is one in which an organic material is dispersed in an inorganic material, or one in which an inorganic material is dispersed in an organic material, as described in, for example, JP-A-7-90181. The melting point is lower than that of glass, it can be molded at a low temperature and can be easily produced in large quantities, and the optical system becomes inexpensive. In addition, optical properties with high refractive index and low dispersion are obtained compared to plastics, and heat resistance is excellent. Furthermore, it is hard to be damaged, and can be used, for example, in front balls of optical systems. Therefore, it is desirable to use such an organic-inorganic hybrid material for a lens or prism having at least an aspherical surface.
[0072]
When the first lens group or the lens group closest to the image side has an aspheric surface, the lens or prism on which the aspheric surface is formed can be made of plastic.
[0073]
When the prism is made of plastic, a large amount of prisms or lenses having aspherical surfaces can be easily produced by a plastic molding method. Moreover, since the material cost is low, an inexpensive prism and an inexpensive optical system can be obtained. In addition, since plastic is lighter than glass, the weight of the optical system can be reduced.
[0074]
In the optical path bending zoom optical system according to the present invention, the prism can be made of plastic.
[0075]
The prism has a larger volume than other lenses, and if the prism is made of light plastic, it is particularly effective in reducing the weight. Moreover, it can be produced by a plastic molding method and can be easily produced in large quantities. Furthermore, since the material cost is low, an inexpensive optical system can be obtained.
[0076]
In the optical path bending zoom optical system of the present invention, all the lenses and prisms can be made of plastic.
[0077]
When all the lenses and prisms are made of plastic, all the lenses and prisms can be produced by a plastic molding method and can be easily produced in large quantities. In addition, since the material cost is low, an inexpensive optical system can be obtained.
[0078]
In the optical path bending zoom optical system according to the present invention, it is desirable that the optical axis be bent so that the bent surface of the optical axis is parallel to the short side of the imaging surface of the imaging device arranged on the image surface.
[0079]
For example, if the optical axis is bent in the short side direction of the CCD arranged on the image plane, the outermost position on the CCD in the bent direction becomes lower than that in the case of bending in the long side direction. Therefore, the size of the reflecting surface can be reduced, the thickness of the prism can be reduced, and the optical system can be made thinner.
[0080]
In the optical path bending zoom optical system according to the present invention, it is desirable that the prism is disposed closer to the object side than the most object side lens of all lens groups movable during zooming.
[0081]
That is, in order not to complicate the zoom and focus drive system, the moving group is preferably on the image side with respect to the folding position.
[0082]
In the optical path bending zoom optical system of the present invention, the lens group that moves during zooming can be moved monotonously to the object side when zooming from the wide-angle end to the telephoto end.
[0083]
If the lens group that moves at the time of zooming is moved monotonously to the object side, the mechanism for movement becomes simple.
[0084]
In the optical path bending zoom optical system according to the present invention, it is desirable to dispose at least one aperture stop on the optical path closer to the image side than the prism.
[0085]
If the aperture stop is provided on the object side of the prism, the optical path length on the object side of the prism becomes longer and the optical system becomes thicker.
[0086]
Further, when the third lens group having a positive refractive power is included, the third lens group can be moved in the optical axis direction for focusing.
[0087]
The third lens group moves at the time of zooming, and when the third lens group is focused, the moving mechanism for zooming can be used even at the time of focusing, the mechanism becomes simple, and the entire optical system including the mechanism Can be reduced in size and weight.
[0088]
Further, the zoom optical system of the present invention as described above, an electronic image sensor arranged at a position for receiving an object image formed by the zoom optical system, and an electronic signal photoelectrically converted by the electronic image sensor are processed. Processing means, an input unit for inputting an information signal that the operator wants to input to the processing means, a display element for displaying the output from the processing means, and a recording medium for recording the output from the processing means And an information processing apparatus configured to display the object image received by the electronic image pickup device by the zoom optical system on the display device, based on the present invention.
[0089]
In this case, a personal computer device in which the input unit is configured by a keyboard and the zoom optical system and the electronic imaging element are built in the peripheral part of the display element or the peripheral part of the keyboard can be configured based on the present invention. it can.
[0090]
Further, the zoom optical system of the present invention as described above, an electronic image sensor arranged at a position for receiving an object image formed by the zoom optical system, an antenna for transmitting and receiving telephone signals, and a telephone A telephone apparatus including an input unit for inputting a signal such as a number and a signal processing unit for converting an object image received by the electronic image sensor into a signal that can be transmitted is configured according to the present invention. Can do.
[0091]
Further, the zoom optical system of the present invention as described above, an electronic image sensor arranged at a position for receiving an object image formed by the zoom optical system, and an electronic signal photoelectrically converted by the electronic image sensor are processed. Or a display element that displays the object image received by the electronic image sensor so as to be observable, and has a recording member for recording image information of the object image received by the electronic image sensor. A display processing function configured to display the object image received by the electronic image sensor on the display element, and a recording process for recording the object image received by the electronic image sensor on a recording medium. An electronic camera device having a function can be configured based on the present invention.
[0092]
With this configuration, the digital camera itself can be made thin. Further, even if an imaging function is installed in a portable terminal such as a portable personal computer or a cellular phone, the size of the portable terminal need not be increased.
[0093]
DETAILED DESCRIPTION OF THE INVENTION
Examples 1 to 10 of the optical path bending zoom optical system according to the present invention will be described below. FIGS. 1 to 10 show lens cross-sectional views at the wide-angle end (a), the intermediate state (b), and the telephoto end (c) at the time of focusing on an object point at infinity, respectively. In each figure, the first lens group is G1, the second lens group is G2, the third lens group is G3, the fourth lens group is G4, the optical path bending prism is P, the aperture stop is S, the near-infrared cut filter, the low-pass A parallel plane plate group such as a filter and a cover glass of a CCD which is an electronic image pickup device is indicated by F, and an image plane of the CCD is indicated by I. The parallel plane plate group F is fixedly disposed between the final lens group and the image plane I. ing.
[0094]
As shown in FIG. 1, the optical path bending zoom optical system according to the first embodiment includes an optical path bending prism P equivalent to a biconcave negative lens, a negative meniscus lens convex on the image plane side, and a biconvex positive lens. 1st lens group G1, aperture stop S, 2nd biconvex positive lens, 2nd lens group G2 which consists of a negative meniscus lens convex on the object side, 3rd lens group G3 which consists of 1 biconvex positive lens, both The fourth lens group G4 is composed of a single convex positive lens. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, and the aperture stop S and the second lens group G2 are integrated with the object side. The third lens group G3 moves to the object side while once narrowing the distance from the second lens group G2 and then narrowing it, and the fourth lens group G4 is fixed.
[0095]
The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the negative meniscus lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. Used on four sides.
[0096]
In this embodiment, the optical path bending prism P is made of plastic.
[0097]
As shown in FIG. 2, the optical path bending zoom optical system of Example 2 includes an optical path bending prism P equivalent to a biconcave negative lens, a negative meniscus lens convex on the image plane side, and a biconvex positive lens. A first lens group G1, an aperture stop S, a second lens group G2 composed of two biconvex positive lenses and a negative meniscus lens convex on the object side, and a third lens composed of one positive meniscus lens convex on the object side The first lens group G1 is fixed and the aperture stop S and the second lens group G2 are fixed when zooming from the wide-angle end to the telephoto end. The third lens group G3 moves toward the object side, and the third lens group G3 moves toward the object side while narrowing the distance from the second lens group G2, and then the fourth lens group G4 is fixed.
[0098]
The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the negative meniscus lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. Used on four sides.
[0099]
In this embodiment, the optical path bending prism P is made of plastic.
[0100]
As shown in FIG. 3, the optical path bending zoom optical system of Embodiment 3 includes an optical path bending prism P equivalent to a negative meniscus lens convex on the object side, a biconcave negative lens, and a positive meniscus lens convex on the object side. A first lens group G1, comprising an aperture stop S, two biconvex positive lenses, a second lens group G2 comprising a negative meniscus lens convex on the object side, and a third lens group comprising one biconvex positive lens. G3 is composed of a fourth lens group G4 composed of a single positive meniscus lens convex on the image surface side. When zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed and the aperture stop S is on the object side. The second lens group G2 moves toward the object side while narrowing the distance from the aperture stop S, and the third lens group G3 moves toward the object side while narrowing the distance from the second lens group G2 and then narrowing it. The fourth lens group G4 moves and is fixed.
[0101]
The aspheric surfaces are the object side surface of the biconcave negative lens of the first lens group G1, the object side surface of the positive meniscus lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. It is used on four of the surfaces.
[0102]
In this embodiment, all elements including the optical path bending prism P are made of glass.
[0103]
As shown in FIG. 4, the optical path bending zoom optical system of Example 4 includes an optical path bending prism P equivalent to a biconcave negative lens and a first lens group G1 composed of a biconvex positive lens, an aperture stop S, and a biconvex lens. A second lens group G2 composed of a positive lens, a positive meniscus lens convex on the object side, and a negative meniscus lens convex on the object side, a positive meniscus lens convex on the object side, and a negative meniscus lens convex on the object side The third lens group G3, and the fourth lens group G4 consisting of one positive meniscus lens convex on the object side. When zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed and has an aperture. The diaphragm S moves to the object side, the second lens group G2 moves to the object side while narrowing the distance from the aperture stop S, and the third lens group G3 once widens the distance from the second lens group G2. Move to the object side while narrowing, 4th lens Group G4 is fixed.
[0104]
The aspheric surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the biconvex positive lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. Are used on four sides.
[0105]
In this embodiment, all elements including the optical path bending prism P are made of glass.
[0106]
As shown in FIG. 5, the optical path bending zoom optical system according to the fifth embodiment includes a first lens group G1 including an optical path bending prism P equivalent to a biconcave negative lens and a biconvex positive lens, an aperture stop S, and a biconvex lens. A second lens group G2 composed of a positive lens, a positive meniscus lens convex on the object side, a negative meniscus lens convex on the object side, a biconvex positive lens, and a negative meniscus lens convex on the image side. The third lens group G3 includes a fourth lens group G4 including one positive meniscus lens convex on the object side. When zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed and the aperture stop S is Moving to the object side, the second lens group G2 moves to the object side while narrowing the distance from the aperture stop S, the third lens group G3 moves to the object side while increasing the distance from the second lens group G2, The fourth lens group G4 is fixed.
[0107]
The aspheric surfaces are used for the three surfaces of the object side surface of the biconvex positive lens of the first lens group G1, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. .
[0108]
In this embodiment, all elements including the optical path bending prism P are made of glass.
[0109]
As shown in FIG. 6, the optical path bending zoom optical system of Embodiment 6 includes a first lens group G1 including an optical path bending prism P equivalent to a biconcave negative lens and a positive meniscus lens convex on the object side, an aperture stop. S, a second lens group G2 composed of a biconvex positive lens, a positive meniscus lens convex on the object side, and a negative meniscus lens convex on the object side, and a third lens composed of one positive meniscus lens convex on the object side The first lens group G1 is fixed and the aperture stop S moves to the object side when zooming from the wide-angle end to the telephoto end. The second lens group G2 moves to the object side while narrowing the distance from the aperture stop S and then widens, and the third lens group G3 moves to the object side while narrowing the distance from the second lens group G2 and then narrows it. The fourth lens group G4 is fixed That.
[0110]
The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the positive meniscus lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. Used on four sides.
[0111]
In this embodiment, the optical path bending prism P is made of plastic.
[0112]
As shown in FIG. 7, the optical path bending zoom optical system according to the seventh embodiment includes an optical path bending prism P equivalent to a biconcave negative lens and a first lens group G1 composed of a biconvex positive lens, an aperture stop S, and two lenses. A second lens group G2 composed of a biconvex positive lens and a biconcave negative lens, a third lens group G3 composed of a biconvex positive lens and a negative meniscus lens convex on the image side, and a positive positive convex on the object side. The fourth lens group G4 is composed of a single meniscus lens. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the aperture stop S moves to the object side, and the second lens group G2 Moves to the object side while narrowing the distance to the aperture stop S, the third lens group G3 moves to the object side while narrowing the distance from the second lens group G2, and then moves to the object side. The fourth lens group G4 It is fixed.
[0113]
The aspheric surfaces are used for the three surfaces of the object side surface of the biconvex positive lens of the first lens group G1, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. .
[0114]
In this embodiment, the three lenses of the second lens group G2 are made of plastic.
[0115]
As shown in FIG. 8, the optical path bending zoom optical system according to the eighth embodiment includes a first lens group G1 including an optical path bending prism P equivalent to a biconcave negative lens and a positive meniscus lens convex on the object side, an aperture stop. S, a second lens group G2 composed of two biconvex positive lenses and a biconcave negative lens, a third lens group G3 composed of a biconvex positive lens and a biconcave negative lens, and a positive meniscus convex on the object side The fourth lens group G4 is composed of one lens. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the aperture stop S moves to the object side, and the second lens group G2 The third lens group G3 moves toward the object side while narrowing the distance from the aperture stop S, and the third lens group G3 moves toward the object side while narrowing the distance from the second lens group G2, and the fourth lens group G4 is fixed. It is.
[0116]
The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the positive meniscus lens, the most object side surface of the second lens group G2, and the most object side surface of the third lens group G3. The fourth lens group G4 is used for five object-side surfaces.
[0117]
In this embodiment, all the lenses and prisms of the first lens group G1 to the fourth lens group G4 are made of plastic.
[0118]
As shown in FIG. 9, the optical path bending zoom optical system of Example 9 includes a first lens group G1 including an optical path bending prism P equivalent to a biconcave negative lens, a biconcave negative lens, and a biconvex positive lens. Aperture stop S, a second lens group G2 composed of two biconvex positive lenses and a negative meniscus lens convex on the object side, a third lens group G3 composed of one positive meniscus lens convex on the object side, biconvex The fourth lens group G4 is composed of one positive lens. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the object side, and the first lens The aperture stop S between the group G1 and the second lens group G2 is integrated with the second lens group G2 while narrowing the distance from the second lens group G2 from the wide-angle end to the intermediate state, and from the intermediate state to the telephoto end. The third lens group G3 moves with the second lens group G2. While narrowing is once spread its septum moves to the object side, the fourth lens group G4 are fixed.
[0119]
The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the biconcave negative lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. Are used on four sides.
[0120]
In this embodiment, the optical path bending prism P is made of plastic.
[0121]
As shown in FIG. 10, the optical path bending zoom optical system of Example 10 includes a first lens group G1 including an optical path bending prism P equivalent to a biconcave negative lens, a biconcave negative lens, and a biconvex positive lens. Aperture stop S, a second lens group G2 composed of two biconvex positive lenses and a negative meniscus lens convex on the object side, a third lens group G3 composed of one positive meniscus lens convex on the object side, biconvex The fourth lens group G4 is composed of a single positive lens. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the aperture stop S moves to the object side, and the second lens group G2 Moves to the object side while narrowing the distance to the aperture stop S, the third lens group G3 moves to the object side while narrowing the distance from the second lens group G2, and then moves to the object side. The fourth lens group G4 It is fixed.
[0122]
The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the biconcave negative lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. Are used on four sides.
[0123]
In this embodiment, the optical path bending prism P is made of plastic.
[0124]
In Examples 1 to 10, the first lens group G1 has a negative refractive power, the second lens group G2, the third lens group G3, and the fourth lens group G4 have a positive refractive power. The third lens group G3 is extended toward the object side to focus on a short distance object.
[0125]
In the following, numerical data of each of the above embodiments is shown. Symbols are the above, f is the focal length of the entire system, 2ω is the angle of view, F_NOIs the F number, WE is the wide angle end, ST is the intermediate state, TE is the telephoto end, r₁, R₂... is the radius of curvature of each lens surface, d₁, D₂... is the distance between each lens surface, n_d1, N_d2... is the refractive index of d-line of each lens, ν_d1, Ν_d2... is the Abbe number of each lens. “RE” indicates a reflecting surface. The aspherical shape is represented by the following formula, where x is an optical axis with the light traveling direction being positive, and y is a direction orthogonal to the optical axis.
[0126]

Where r is the paraxial radius of curvature, K is the cone coefficient, A_Four, A₆, A₈, A_TenAre the 4th, 6th, 8th and 10th order aspherical coefficients, respectively.
[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]
FIG. 11 is an aberration diagram for Example 1 upon focusing on an object point at infinity. In this aberration diagram, SA is spherical aberration, AS is astigmatism, CC is lateral chromatic aberration, and DT is distortion. In the figure, “FIY” represents the image height.
[0138]
Next, nd, f related to the conditions (1) to (5) in the above embodiments._1G/ √ (f_w× f_t), M_Three/ M₂, -Β_Rt, DFT / f_tIndicates the value of.

[0139]
In Examples 1 to 10 above, the refractive index n of the following d-line_d, Abbe number ν_dThe transition point Tg of the glass having is as follows.
[0140]

[0141]
In each of the above embodiments, the refractive index n of the following d-line_d, Abbe number ν_dThe medium having is plastic.
[0142]

[0143]
In each of the above embodiments, all of the optical path bending prisms P provided with an aspheric surface are provided with an aspheric surface on the entrance surface, but may be provided with an aspheric surface on the exit surface.
[0144]
In all of the above embodiments, the prism P is used as the first element on the most object side of the optical system. However, as schematically shown in FIG. 12, a single lens is provided on the front side (object side) of the prism P. Alternatively, a single lens group A or a plurality of lens groups A composed of a plurality of lenses may be arranged and moved along the optical axis for focusing or zooming.
[0145]
The optical path bending zoom optical system according to the present invention as described above forms an object image with an imaging optical system such as a zoom lens, and the image is received by an image sensor such as a CCD or a silver salt film to take a picture. In particular, it can be used for a digital camera, a video camera, a personal computer which is an example of an information processing device, a telephone, a portable terminal, particularly a portable phone which is convenient to carry. The embodiment is illustrated below.
[0146]
FIG. 13 to FIG. 15 are conceptual diagrams of structures in which the zoom optical system according to the present invention is incorporated in the photographing optical system 41 of a digital camera. 13 is a front perspective view showing the appearance of the digital camera 40, FIG. 14 is a rear perspective view thereof, and FIG. 15 is a cross-sectional view showing the configuration of the digital camera 40. In this example, the digital camera 40 includes a photographing optical system 41 having a photographing optical path 42, a finder optical system 43 having a finder optical path 44, a shutter 45, a flash 46, a liquid crystal display monitor 47, and the like. When the shutter 45 disposed in the position is pressed, photographing is performed through the photographing optical system 41, for example, the optical path bending zoom optical system of the fifth embodiment in conjunction with it. An object image formed by the photographic optical system 41 is formed on the imaging surface of the CCD 49 through a near-infrared cut filter and an optical low-pass filter in the plane parallel plate group F. The object image received by the CCD 49 is displayed as an electronic image on the liquid crystal display monitor 47 provided on the back of the camera via the processing means 51. Further, the processing means 51 is connected to a recording means 52 so that a photographed electronic image can be recorded. The recording means 52 may be provided separately from the processing means 51, or may be configured to perform recording / writing electronically using a floppy disk, memory card, MO, or the like. Further, it may be configured as a silver salt camera in which a silver salt film is arranged in place of the CCD 49.
[0147]
Further, a finder objective optical system 53 is disposed on the finder optical path 44. The object image formed by the finder objective optical system 53 is formed on the field frame 57 of the Porro prism 55 which is an image erecting member. Behind this polyprism 55 is an eyepiece optical system 59 that guides the erect image to the observer eyeball E. Note that cover members 50 are disposed on the incident side of the photographing optical system 41 and the finder objective optical system 53 and on the exit side of the eyepiece optical system 59, respectively.
[0148]
The digital camera 40 configured in this manner is a zoom lens with a large back focus, a photographing optical system 41 having a wide angle of view and a high zoom ratio, good aberration, bright, and a filter that can be arranged with a high back focus. Performance and cost reduction can be realized.
[0149]
In the example of FIG. 15, a parallel plane plate is disposed as the cover member 50, but a lens having power may be used.
[0150]
Next, a personal computer which is an example of an information processing apparatus in which the zoom optical system of the present invention is incorporated as an objective optical system is shown in FIGS. 16 is a front perspective view with the cover of the personal computer 300 opened, FIG. 17 is a sectional view of the photographing optical system 303 of the personal computer 300, and FIG. 18 is a side view of the state of FIG. As shown in FIGS. 16 to 18, the personal computer 300 includes a keyboard 301 for a writer to input information from the outside, information processing means and recording means not shown, and a monitor for displaying information to the operator. 302 and a photographing optical system 303 for photographing the operator himself and surrounding images. Here, the monitor 302 may be a transmissive liquid crystal display element that is illuminated from the back by a backlight (not shown), a reflective liquid crystal display element that reflects and displays light from the front, a CRT display, or the like. Further, in the drawing, the photographing optical system 303 is built in the upper right of the monitor 302. However, the imaging optical system 303 is not limited to the place, and may be anywhere around the monitor 302 or the keyboard 301.
[0151]
The photographing optical system 303 has an objective lens 112 including an optical path bending zoom optical system (abbreviated in the drawing) according to the present invention and an image pickup element chip 162 that receives an image on a photographing optical path 304. These are built in the personal computer 300.
[0152]
Here, an optical low-pass filter LF is additionally attached on the image sensor chip 162 to be integrally formed as an image pickup unit 160, and can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, the center alignment of the objective lens 112 and the image sensor chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is simple. Further, a cover glass 114 for protecting the objective lens 112 is disposed at the tip (not shown) of the lens frame 113. The zoom lens driving mechanism and the like in the lens frame 113 are not shown.
[0153]
The object image received by the image sensor chip 162 is input to the processing means of the personal computer 300 via the terminal 166 and is displayed on the monitor 302 as an electronic image. FIG. A rendered image 305 is shown. The image 305 can also be displayed on the personal computer of the communication partner from a remote location via the processing means, the Internet, or the telephone.
[0154]
Next, FIG. 19 shows a telephone, which is an example of an information processing apparatus in which the zoom optical system of the present invention is incorporated as a photographing optical system, particularly a portable telephone that is convenient to carry. 19A is a front view of the mobile phone 400, FIG. 19B is a side view, and FIG. 19C is a cross-sectional view of the photographing optical system 405. As shown in FIGS. 19A to 19C, the mobile phone 400 includes a microphone unit 401 that inputs an operator's voice as information, a speaker unit 402 that outputs the voice of the other party, and an operator who receives information. An input dial 403 for inputting information, a monitor 404 for displaying information such as a photographed image and a telephone number of the operator and the other party, a photographing optical system 405, an antenna 406 for transmitting and receiving communication radio waves, and an image And processing means (not shown) for processing information, communication information, input signals, and the like. Here, the monitor 404 is a liquid crystal display element. In the drawing, the arrangement positions of the respective components are not particularly limited to these. The photographing optical system 405 includes an objective lens 112 that is an optical path bending zoom optical system (abbreviated in the drawing) according to the present invention disposed on a photographing optical path 407, and an image sensor chip 162 that receives an object image. . These are built in the mobile phone 400.
[0155]
Here, an optical low-pass filter LF is additionally attached on the image sensor chip 162 to be integrally formed as an image pickup unit 160, and can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, the center alignment of the objective lens 112 and the image sensor chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is simple. Further, a cover glass 114 for protecting the objective lens 112 is disposed at the tip (not shown) of the lens frame 113. The zoom lens driving mechanism and the like in the lens frame 113 are not shown.
[0156]
The object image received by the imaging element chip 162 is input to the processing means (not shown) via the terminal 166 and displayed as an electronic image on the monitor 404, the monitor of the communication partner, or both. . Further, when transmitting an image to a communication partner, the processing means includes a signal processing function for converting information of an object image received by the image sensor chip 162 into a signal that can be transmitted.
[0157]
The optical path bending zoom optical system and the apparatus using the same according to the present invention can be configured as follows, for example.
[0158]
[1] At least a first lens group having negative refractive power, a second lens group having positive refractive power, and at least one subsequent lens group in order from the object side, from the wide-angle end to the telephoto end In zoom optical system including at least one lens unit that moves along the optical axis including the second lens unit when zooming to
The first lens group includes a prism including at least one reflecting surface for bending an optical path, an incident surface, and an exit surface, and at least one of the entrance surface and the exit surface of the prism rotates about an optical axis. An optical path bending zoom optical system characterized by a symmetric curved surface.
[0159]
[2] At least one first lens group having a negative refractive power and including at least one prism having a negative refractive power, a second lens group having a positive refractive power, and at least one thereafter, in order from the object side In a zoom optical system comprising two lens groups and including at least one lens group that moves along the optical axis including the second lens group when zooming from the wide-angle end to the telephoto end,
The prism includes at least one reflecting surface for bending an optical path, an incident surface, and an exit surface, and at least one of the entrance surface and the exit surface is a curved surface. Optical system.
[0160]
[3] At least a first lens group having a negative refractive power, a second lens group having a positive refractive power, and at least one lens group thereafter, in order from the object side, from the wide-angle end to the telephoto end In zoom optical system including at least one lens unit that moves along the optical axis including the second lens unit when zooming to
The first lens group includes a prism including at least one reflecting surface for bending an optical path, an incident surface, and an exit surface, and at least one of the incident surface and the exit surface of the prism is a curved surface, An optical path bending zoom optical system characterized in that the refractive index nd of the prism at the d-line satisfies the following conditional expression (1).
[0161]
1.6 <nd <2.0 (1)
[4] The optical path bending zoom optical system according to any one of 1 to 3, wherein the following conditional expression (2) is satisfied.
[0162]
−5.0 <f_1G/ √ (f_w× f_t) <− 0.3 (2)
Where f_1GIs the focal length of the first lens group, f_wIs the focal length of the entire system when focusing on an object point at infinity at the wide-angle end, f_tIs the focal length of the entire system when focusing on an object point at infinity at the telephoto end.
[0163]
[5] In any one of the above items 1 to 3, the second lens unit includes a third lens unit having a positive refractive power after the second lens unit, and the second lens unit has a second zoom lens when zooming from the wide angle end to the telephoto end. An optical path bending zoom optical system, wherein the lens group and the third lens group move along an optical axis while changing a relative distance.
[0164]
[6] In the above 5, the amount of movement of each of the second lens group and the third lens group at the time of zooming from the wide-angle end to the telephoto end when focusing on infinity is M₂, M_ThreeThen, the optical path bending zoom optical system characterized by satisfying the following conditional expression (3).
[0165]
0.3 <M_Three/ M₂<3.0 (3)
[7] In the above 5, the magnification β of the composite system after the second lens unit at the telephoto end_RtSatisfying the following conditional expression (4): an optical path bending zoom optical system.
[0166]
1.0 <−β_Rt<2.3 (4)
[8] The optical path folding zoom optical system according to any one of items 1 to 3, wherein the lens group closest to the image side has at least one aspheric surface.
[0167]
[9] The optical path folding zoom optical system according to 8, wherein the lens unit closest to the image side is fixed at the time of zooming and focusing.
[0168]
[10] The optical path folding zoom optical system according to 9, wherein the second lens group from the image side is moved in the optical axis direction to be focused.
[0169]
[11] The optical path bending zoom optical system according to any one of items 1 to 3, wherein the first lens group has at least one aspheric surface.
[0170]
[12] The optical path bending zoom optical system as described in 11 above, wherein the first lens group is fixed at the time of zooming and focusing.
[0171]
[13] In any one of the above items 1 to 3, the lens group disposed on the image side from the prism or a part of the lens group disposed on the image side from the prism in the optical axis direction. An optical path bending zoom optical system characterized by focusing by moving.
[0172]
[14] In the above 10, the air space DFT on the optical axis at the time of focusing on an object point at infinity at the telephoto end of the second lens unit and the third lens unit from the image side satisfies the following conditional expression (5): An optical path bending zoom optical system.
[0173]
0.01 <DFT / f_t<2.0 (5)
Where f_tIs the focal length of the entire system when focusing on an object point at infinity at the telephoto end.
[0174]
[15] In the above item 5, the first lens group includes one prism having negative refractive power, one negative lens, and one positive lens, and the third lens group includes one positive lens. An optical path bending zoom optical system comprising a lens.
[0175]
[16] In the above item 5, the first lens group includes one prism having negative refractive power and one positive lens, and the third lens group includes one positive lens and one positive lens. An optical path bending zoom optical system comprising a negative lens.
[0176]
[17] The optical path bending zoom optical system according to 15 or 16, wherein the third lens group is focused by moving in the optical axis direction.
[0177]
[18] The optical path bending zoom optical system as described in 11 above, wherein at least one of the incident surface and the exit surface of the prism is an aspherical surface.
[0178]
[19] The optical path bending zoom optical system according to 8 or 11, wherein the lens or prism on which the aspheric surface is formed is made of glass, and a transition point Tg thereof satisfies the following conditional expression (6).
[0179]
60 ° C <Tg <620 ° C (6)
[20] The optical path bending zoom optical system according to 8 or 11, wherein the lens or prism on which the aspherical surface is formed is processed by a glass molding method.
[0180]
[21] The optical path bending zoom optical system according to 8 or 11, wherein the lens or prism on which the aspheric surface is formed is made of an organic-inorganic hybrid material.
[0181]
[22] The optical path bending zoom optical system according to 8 or 11, wherein the lens or prism on which the aspherical surface is formed is made of plastic.
[0182]
[23] The optical path bending zoom optical system according to any one of items 1 to 3, wherein the prism is made of plastic.
[0183]
[24] The optical path bending zoom optical system according to any one of items 1 to 3, wherein all the lenses and prisms are made of plastic.
[0184]
[25] In any one of the above items 1 to 3, the optical axis is bent so that the bent surface of the optical axis is parallel to the short side of the imaging surface of the imaging device disposed on the image surface. Optical path bending zoom optical system.
[0185]
[26] The optical path bending zoom according to any one of items 1 to 3, wherein the prism is disposed closer to the object side than a lens closest to the object side of all lens groups movable during zooming. Optical system.
[0186]
[27] The optical path bending zoom according to any one of items 1 to 3, wherein the lens group that moves at the time of zooming moves monotonously toward the object side when zooming from the wide-angle end to the telephoto end. Optical system.
[0187]
[28] The optical path bending zoom optical system according to any one of items 1 to 3, wherein at least one aperture stop is disposed on the optical path closer to the image side than the prism.
[0188]
[29] The optical path bending zoom optical system as set forth in 5, wherein the third lens group is moved in the optical axis direction to be focused.
[0189]
[30] The optical path folding zoom optical system according to any one of 1 to 29 above, an electronic imaging device arranged at a position for receiving an object image formed by the optical path folding zoom optical system, and the electronic imaging device Processing means for processing the electronic signal photoelectrically converted by the input device, an input unit for inputting an information signal that an operator wants to input to the processing means, a display element for displaying an output from the processing means, and the processing means A recording medium for recording the output from
The information processing apparatus, wherein the processing means is configured to display an object image received by the electronic imaging element by the optical path bending zoom optical system on the display element.
[0190]
[31] In the above item 30,
The personal computer device, wherein the input unit is configured by a keyboard, and the optical path bending zoom optical system and the electronic imaging device are built in a peripheral part of the display element or a peripheral part of the keyboard.
[0191]
[32] The optical path bending zoom optical system according to any one of 1 to 29 above, an electronic imaging device disposed at a position for receiving an object image formed by the optical path bending zoom optical system, and a telephone signal are transmitted. And an antenna for receiving, an input unit for inputting a signal such as a telephone number, and a signal processing unit for converting an object image received by the electronic image sensor into a signal that can be transmitted. Feature telephone equipment.
[0192]
[33] The optical path bending zoom optical system according to any one of 1 to 29 above, an electronic imaging device disposed at a position for receiving an object image formed by the optical path bending zoom optical system, and the electronic imaging device Image processing means for processing the electronic signal photoelectrically converted by the image sensor and a display element for observably displaying the object image received by the electronic image sensor, and image information of the object image received by the electronic image sensor A recording member for recording the image, and a display processing function for displaying an object image received by the electronic image sensor on the display element; and An electronic camera apparatus, comprising: a recording processing function for recording a received object image on the recording medium.
[0193]
【The invention's effect】
As is apparent from the above description, according to the present invention, a thin zoom optical system that can be mounted on a small digital still camera, a portable terminal, etc., which bends the optical axis to reduce the thickness and provides power to the bending prism. An optical path bending zoom optical system can be provided.
[Brief description of the drawings]
FIG. 1 is a lens cross-sectional view at a wide-angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to Example 1 of the optical path bending zoom optical system of the present invention.
2 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Embodiment 2. FIG.
3 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 3. FIG.
4 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Embodiment 4. FIG.
5 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Embodiment 5. FIG.
6 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 6. FIG.
7 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Embodiment 7. FIG.
8 is a lens cross-sectional view similar to FIG. 1 of an optical path bending zoom optical system according to an eighth embodiment. FIG.
9 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 9. FIG.
10 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system according to Example 10. FIG.
FIG. 11 is an aberration diagram for Example 1 upon focusing on an object point at infinity.
FIG. 12 is a diagram schematically showing a configuration of a modification of the optical path bending zoom optical system of the present invention.
FIG. 13 is a front perspective view showing an appearance of a digital camera incorporating the optical path bending zoom optical system according to the present invention.
14 is a rear perspective view of the digital camera of FIG.
15 is a cross-sectional view of the digital camera of FIG.
FIG. 16 is a front perspective view in which a cover of a personal computer in which the optical path bending zoom optical system according to the present invention is incorporated as an objective optical system is opened.
FIG. 17 is a cross-sectional view of a photographing optical system of a personal computer.
18 is a side view of the state of FIG.
FIG. 19 is a front view, a side view, and a sectional view of the photographing optical system of a mobile phone in which the optical path bending zoom optical system according to the present invention is incorporated as an objective optical system.
[Explanation of symbols]
G1: First lens group
G2: Second lens group
G3 ... Third lens group
G4 ... Fourth lens group
P ... Optical path bending prism
S: Aperture stop (in the case of independent)
F ... Parallel plane plate group
I ... Image plane
A: Focusing lens group or zooming lens group
E ... Observer eyeball
LF: Optical low-pass filter
40 ... Digital camera
41. Photography optical system
42. Optical path for photographing
43. Viewfinder optical system
44. Optical path for viewfinder
45 ... Shutter
46 ... Flash
47 ... LCD monitor
49 ... CCD
50. Cover member
51. Processing means
52. Recording means
53. Objective optical system for viewfinder
55 ... Porro prism
57 ... View frame
59 ... Eyepiece optical system
112 ... Objective lens
113 ... Mirror frame
114 ... cover glass
160: Imaging unit
162. Image sensor chip
166 ... Terminal
300 ... PC
301 ... Keyboard
302 ... Monitor
303 ... Shooting optical system
304: Optical path for photographing
305 ... Image
400 ... mobile phone
401: Microphone part
402: Speaker unit
403 ... Input dial
404 ... Monitor
405 ... Shooting optical system
406 ... Antenna
407: Photography optical path

Claims (11)

The zoom lens includes at least a first lens group having a negative refractive power, a second lens group having a positive refractive power, and at least one subsequent lens group in order from the object side, and zooming from the wide-angle end to the telephoto end. In the zoom optical system including at least one lens unit that moves along the optical axis including the second lens unit,
The first lens group includes a prism including one reflecting surface for bending an optical path, an incident surface, and an exit surface, and at least one of the incident surface and the exit surface of the prism is rotationally symmetric with respect to the optical axis. curved surface der such is,
The zoom optical system, the optical path bending zoom optical system according to claim Rukoto only one surface having a reflecting surface. A first lens group having at least one prism having negative refractive power and at least one negative refractive power in order from the object side, a second lens group having positive refractive power, and at least one lens group thereafter A zoom optical system including at least one lens unit including the second lens unit and moving along the optical axis when zooming from the wide-angle end to the telephoto end.
The prism has a first surface of the reflecting surface for bending the optical path includes an entrance surface and an exit surface, and the incident surface, Ri least one curved surface der exit surface,
The zoom optical system, the optical path bending zoom optical system according to claim Rukoto only one surface having a reflecting surface. The zoom lens includes at least a first lens group having a negative refractive power, a second lens group having a positive refractive power, and at least one subsequent lens group in order from the object side, and zooming from the wide-angle end to the telephoto end. In the zoom optical system including at least one lens unit that moves along the optical axis including the second lens unit,
The first lens group includes a prism including one reflecting surface for bending an optical path, an incident surface, and an exit surface, and at least one of the entrance surface and the exit surface of the prism is a curved surface, refractive index nd at d-line of the prism meets the following condition (1),
The zoom optical system has an optical path bending zoom optical system having only one reflecting surface .
1.6 <nd <2.0 (1) 4. The optical path bending zoom optical system according to claim 1, wherein the following conditional expression (2) is satisfied.
−5.0 <f _1G / √ (f _w × f _t ) <− 0.3 (2)
However, f _1G is the focal length of the first lens group, f _w is the focal length of the focal point at infinity at the wide-angle end, f _t is the focal point at infinity at the telephoto end all The focal length of the system.   4. The second lens group according to claim 1, further comprising a third lens group having a positive refractive power after the second lens group and performing zooming from the wide-angle end to the telephoto end. 5. And the third lens group moves along the optical axis while changing the relative distance. In claim 5, when the movement amounts of the second lens group and the third lens group at the time of zooming from the wide-angle end to the telephoto end at the time of focusing on infinity are M ₂ and M ₃ , the following conditional expressions: An optical path folding zoom optical system satisfying (3).
0.3 <M ₃ / M ₂ <3.0 (3) _{6. The} optical path bending zoom optical system according to claim 5, wherein the magnification β _Rt of the synthesis system after the second lens unit at the telephoto end satisfies the following conditional expression (4).
1.0 <−β _Rt <2.3 (4) 4. The optical path bending zoom optical system according to claim 1, wherein the following conditional expression (2 ') is satisfied.
−5.0 <f _1G / √ (f _w  × f _t  ) ≦ −0.9674 (2 ′)
Where f _1G Is the focal length of the first lens group, f _w  Is the focal length of the entire system when focusing on an object point at infinity at the wide-angle end, f _t  Is the focal length of the entire system when focusing on an object point at infinity at the telephoto end. 6. The amount of movement of each of the second lens group and the third lens group when zooming from the wide-angle end to the telephoto end during infinite focus is defined as M. ₂  , M _Three  Then, an optical path bending zoom optical system satisfying the following conditional expression (3 ′):
0.802 ≦ M _Three  / M ₂  <3.0 (3 ') 6. The magnification β of the composite system after the second lens unit at the telephoto end according to claim 5. _Rt Satisfies the following conditional expression (4 '): an optical path bending zoom optical system.
1.0 <−β _Rt ≦ 1.586 (4 ') The optical path bending zoom optical system according to claim 1, wherein the reflecting surface is a flat surface.

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