JP4262439B2 - Zoom lens and electronic imaging apparatus having the same - Google Patents

Description

【００６９】

【００７０】

【００７１】
第２実施例
図６は本発明による電子撮像装置に用いるズームレンズの第２実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。図７は第２実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【００７２】
第２実施例の電子撮像装置は、図６に示すように、物体側から順に、ズームレンズと、電子撮像素子であるＣＣＤを有している。図６中、ＩはＣＣＤの撮像面である。ズームレンズと撮像面Ｉとの間には、平面平板状のＣＣＤカバーガラスＣＧが設けられている。
ズームレンズは、物体側から順に、第１レンズ群Ｇ１と、第１移動レンズ群である第２レンズ群Ｇ２と、開口絞りＳと、第２移動レンズ群である第３レンズ群Ｇ３と、第４レンズ群Ｇ４とを有している。
第１レンズ群Ｇ１は、物体側から順に、物体側に凸面を向けた負メニスカスレンズＬ１₁と、光路を折り曲げるための反射面を持つ反射光学素子Ｒ１と、両凸正レンズＬ１₂とで構成されている。
反射光学素子Ｒ１は、光路を９０°折り曲げる表面鏡として構成されている。また、表面鏡の反射面は形状可変に構成されており、反射面の形状を変化させることにより合焦動作を行うようになっている。
なお、本発明の各実施例における有効撮像領域の縦横比は３：４であり、折り曲げ方向は横方向である。
第２レンズ群Ｇ２は、物体側から順に、両凹負レンズＬ２₁と物体側に凸面を向けた正メニスカスレンズＬ２₂との接合レンズで構成されており、全体で負の屈折力を有している。
第３レンズ群Ｇ３は、物体側から順に、両凸正レンズＬ３₁と両凹負レンズＬ３₂との接合レンズと、物体側に凸面を向けた正メニスカスレンズＬ３₃とで構成されており、全体で正の屈折力を有している。
第４レンズ群Ｇ４は、物体側から順に、両凹負レンズＬ４₁’と両凸正レンズＬ４₂との接合レンズで構成されている。
【００７３】
広角端から望遠端へと変倍する際には、第１レンズ群Ｇ１及び第４レンズ群Ｇ４は位置が固定され、第２レンズ群Ｇ２は像側に凸状の軌跡で往復移動（即ち、像側へ移動して第１レンズ群Ｇ１との間隔を一旦広げた後、物体側へ移動しながら第１レンズ群Ｇ１との間隔を縮める）し、第３レンズ群Ｇ３は開口絞りＳとともに物体側へのみ移動するようになっている。
また、第１レンズ群Ｇ１と第４レンズ群Ｇ４は、合焦動作時にも位置が固定されている。
非球面は、第１レンズ群Ｇ１中の物体側に凸面を向けた負メニスカスレンズＬ１₁の像側の面、第３レンズ群Ｇ３中の物体側に凸面を向けた正メニスカスレンズＬ３₃の両面、第４レンズ群Ｇ４中の両凸正レンズＬ４₂の像側の面に設けられている。
【００７４】
次に、第２実施例のズームレンズを構成する光学部材の数値データを示す。

【００７５】

【００７６】

【００７７】
第３実施例
図８は本発明による電子撮像装置に用いるズームレンズの第３実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。図９は第３実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。図１０〜図１２は第３実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、図１０は広角端、図１１は中間、図１２は望遠端での状態を示している。
【００７８】
第３実施例の電子撮像装置は、図８に示すように、物体側から順に、ズームレンズと、電子撮像素子であるＣＣＤを有している。図８中、ＩはＣＣＤの撮像面である。ズームレンズと撮像面Ｉとの間には、平面平板状のＣＣＤカバーガラスＣＧが設けられている。
ズームレンズは、物体側から順に、第１レンズ群Ｇ１と、第１移動レンズ群である第２レンズ群Ｇ２と、開口絞りＳと、第２移動レンズ群である第３レンズ群Ｇ３と、第４レンズ群Ｇ４とを有している。
第１レンズ群Ｇ１は、物体側から順に、物体側に凸面を向けた負メニスカスレンズＬ１₁と、光路を折り曲げるための反射面を持つ反射光学素子Ｒ１と、両凸正レンズＬ１₂とで構成されている。
反射光学素子Ｒ１は、光路を９０°折り曲げる表面鏡として構成されている。また、表面鏡の反射面は形状可変に構成されており、反射面の形状を変化させることにより合焦動作を行うようになっている。
なお、本発明の各実施例における有効撮像領域の縦横比は３：４であり、折り曲げ方向は横方向である。
第２レンズ群Ｇ２は、物体側から順に、両凹負レンズＬ２₁と物体側に凸面を向けた正メニスカスレンズＬ２₂との接合レンズで構成されており、全体で負の屈折力を有している。
第３レンズ群Ｇ３は、物体側から順に、両凸正レンズＬ３₁と両凹負レンズＬ３₂と物体側に凸面を向けた正メニスカスレンズＬ３₃との接合レンズで構成されており、全体で正の屈折力を有している。
第４レンズ群Ｇ４は、物体側から順に、物体側に凸面を向けた負メニスカスレンズＬ４₁”と両凸正レンズＬ４₂との接合レンズで構成されている。
【００７９】
広角端から望遠端へと変倍する際には、第１レンズ群Ｇ１及び第４レンズ群Ｇ４は位置が固定され、第２レンズ群Ｇ２は像側に凸状の軌跡で往復移動（即ち、像側へ移動して第１レンズ群Ｇ１との間隔を一旦広げた後、物体側へ移動しながら第１レンズ群Ｇ１との間隔を縮める）し、第３レンズ群Ｇ３は開口絞りＳとともに物体側へのみ移動するようになっている。
また、第１レンズ群Ｇ１と第４レンズ群Ｇ４は、合焦動作時にも位置が固定されている。
非球面は、第１レンズ群Ｇ１中の物体側に凸面を向けた負メニスカスレンズＬ１₁の像側の面、第３レンズ群Ｇ３中の両凸正レンズＬ３₁の物体側の面、物体側に凸面を向けた正メニスカスレンズＬ３₃の像側の面、第４レンズ群Ｇ４中の両凸正レンズＬ４₂の像側の面に設けられている。
【００８０】
次に、第３実施例のズームレンズを構成する光学部材の数値データを示す。

【００８１】

【００８２】

【００８３】
第４実施例
図１３は本発明による電子撮像装置に用いるズームレンズの第４実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。図１４は第４実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。図１５〜図１７は第４実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、図１５は広角端、図１６は中間、図１７は望遠端での状態を示している。
【００８４】
第４実施例の電子撮像装置は、図１３に示すように、物体側から順に、ズームレンズと、電子撮像素子であるＣＣＤを有している。図１３中、ＩはＣＣＤの撮像面である。ズームレンズと撮像面Ｉとの間には、平面平板状のＣＣＤカバーガラスＣＧが設けられている。
ズームレンズは、物体側から順に、第１レンズ群Ｇ１と、第１移動レンズ群である第２レンズ群Ｇ２と、開口絞りＳと、第２移動レンズ群である第３レンズ群Ｇ３と、第４レンズ群Ｇ４とを有している。
第１レンズ群Ｇ１は、物体側から順に、物体側に凸面を向けた負メニスカスレンズＬ１₁と、光路を折り曲げるための反射面を持つ反射光学素子Ｒ１と、両凸正レンズＬ１₂とで構成されている。
反射光学素子Ｒ１は、光路を９０°折り曲げる表面鏡として構成されている。また、表面鏡の反射面は形状可変に構成されており、反射面の形状を変化させることにより合焦動作を行うようになっている。
なお、本発明の各実施例における有効撮像領域の縦横比は３：４であり、折り曲げ方向は横方向である。
第２レンズ群Ｇ２は、物体側から順に、両凹負レンズＬ２₁と物体側に凸面を向けた正メニスカスレンズＬ２₂との接合レンズで構成されており、全体で負の屈折力を有している。
第３レンズ群Ｇ３は、物体側から順に、両凸正レンズＬ３₁と、両凸正レンズＬ３₂’と両凹負レンズＬ３₃’との接合レンズとで構成されており、全体で正の屈折力を有している。
第４レンズ群Ｇ４は、物体側に凸面を向けた正メニスカスレンズＬ４₁”’で構成されている。
【００８５】
広角端から望遠端へと変倍する際には、第１レンズ群Ｇ１及び第４レンズ群Ｇ４は位置が固定され、第２レンズ群Ｇ２は像側に凸状の軌跡で往復移動（即ち、像側へ移動して第１レンズ群Ｇ１との間隔を一旦広げた後、物体側へ移動しながら第１レンズ群Ｇ１との間隔を縮める）し、第３レンズ群Ｇ３は開口絞りＳとともに物体側へのみ移動するようになっている。
また、第１レンズ群Ｇ１と第４レンズ群Ｇ４は、合焦動作時にも位置が固定されている。
非球面は、第１レンズ群Ｇ１中の物体側に凸面を向けた負メニスカスレンズＬ１₁の像側の面、第３レンズ群Ｇ３中の両凸正レンズＬ３₁の物体側の面、第４レンズ群Ｇ４を構成する物体側に凸面を向けた正メニスカスレンズＬ４₁”’の物体側の面に設けられている。
【００８６】
次に、第４実施例のズームレンズを構成する光学部材の数値データを示す。

【００８７】

【００８８】

【００８９】
第５実施例
図１８は本発明による電子撮像装置に用いるズームレンズの第５実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。図１９は第５実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【００９０】
第５実施例の電子撮像装置は、図１８に示すように、物体側から順に、ズームレンズと、電子撮像素子であるＣＣＤを有している。図１８中、ＩはＣＣＤの撮像面である。ズームレンズと撮像面Ｉとの間には、平面平板状のＣＣＤカバーガラスＣＧが設けられている。
ズームレンズは、物体側から順に、第１レンズ群Ｇ１と、第１移動レンズ群である第２レンズ群Ｇ２と、開口絞りＳと、第２移動レンズ群である第３レンズ群Ｇ３と、第４レンズ群Ｇ４とを有している。
第１レンズ群Ｇ１は、物体側から順に、物体側に凸面を向けた負メニスカスレンズＬ１₁と、光路を折り曲げるための反射面を持つ反射光学素子Ｒ１と、両凸正レンズＬ１₂とで構成されている。
反射光学素子Ｒ１は、光路を９０°折り曲げる表面鏡として構成されている。また、表面鏡の反射面は形状可変に構成されており、反射面の形状を変化させることにより合焦動作を行うようになっている。
なお、本発明の各実施例における有効撮像領域の縦横比は３：４であり、折り曲げ方向は横方向である。
第２レンズ群Ｇ２は、物体側から順に、両凹負レンズＬ２₁と物体側に凸面を向けた正メニスカスレンズＬ２₂との接合レンズで構成されており、全体で負の屈折力を有している。
第３レンズ群Ｇ３は、物体側から順に、両凸正レンズＬ３₁と、両凸正レンズＬ３₂’と両凹負レンズＬ３₃’との接合レンズとで構成されており、全体で正の屈折力を有している。
第４レンズ群Ｇ４は、物体側に凹面を向けた正メニスカスレンズＬ４₁で構成されている。
【００９１】
広角端から望遠端へと変倍する際には、第１レンズ群Ｇ１及び第４レンズ群Ｇ４は位置が固定され、第２レンズ群Ｇ２は像側に凸状の軌跡で往復移動（即ち、像側へ移動して第１レンズ群Ｇ１との間隔を一旦広げた後、物体側へ移動しながら第１レンズ群Ｇ１との間隔を縮める）し、第３レンズ群Ｇ３は開口絞りＳとともに物体側へのみ移動するようになっている。
また、第１レンズ群Ｇ１と第４レンズ群Ｇ４は、合焦動作時にも位置が固定されている。
非球面は、第１レンズ群Ｇ１中の物体側に凸面を向けた負メニスカスレンズＬ１₁の像側の面、第３レンズ群Ｇ３中の両凸正レンズＬ３₁の物体側の面、第４レンズ群Ｇ４を構成する物体側に凹面を向けた正メニスカスレンズＬ４₁の像側の面に設けられている。
【００９２】
次に、第５実施例のズームレンズを構成する光学部材の数値データを示す。

【００９３】

【００９４】

【００９５】
第６実施例
図２０は本発明による電子撮像装置に用いるズームレンズの第６実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。図２１は第６実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【００９６】
第６実施例の電子撮像装置は、図２０に示すように、物体側から順に、ズームレンズと、電子撮像素子であるＣＣＤを有している。図２０中、ＩはＣＣＤの撮像面である。ズームレンズと撮像面Ｉとの間には、平面平板状のＣＣＤカバーガラスＣＧが設けられている。
ズームレンズは、物体側から順に、第１レンズ群Ｇ１と、第１移動レンズ群である第２レンズ群Ｇ２と、開口絞りＳと、第２移動レンズ群である第３レンズ群Ｇ３と、第４レンズ群Ｇ４とを有している。
第１レンズ群Ｇ１は、物体側から順に、物体側に凸面を向けた負メニスカスレンズＬ１₁と、光路を折り曲げるための反射面を持つ反射光学素子Ｒ１と、両凸正レンズＬ１₂とで構成されている。
反射光学素子Ｒ１は、光路を９０°折り曲げる表面鏡として構成されている。また、表面鏡の反射面は形状可変に構成されており、反射面の形状を変化させることにより合焦動作を行うようになっている。
なお、本発明の各実施例における有効撮像領域の縦横比は３：４であり、折り曲げ方向は横方向である。
第２レンズ群Ｇ２は、物体側から順に、両凹負レンズＬ２₁と物体側に凸面を向けた正メニスカスレンズＬ２₂との接合レンズで構成されており、全体で負の屈折力を有している。
第３レンズ群Ｇ３は、物体側から順に、両凸正レンズＬ３₁と、両凸正レンズＬ３₂’と両凹負レンズＬ３₃’との接合レンズとで構成されており、全体で正の屈折力を有している。
第４レンズ群Ｇ４は、両凸正レンズＬ４₁””で構成されている。
【００９７】
広角端から望遠端へと変倍する際には、第１レンズ群Ｇ１及び第４レンズ群Ｇ４は位置が固定され、第２レンズ群Ｇ２は像側に凸状の軌跡で往復移動（即ち、像側へ移動して第１レンズ群Ｇ１との間隔を一旦広げた後、物体側へ移動しながら第１レンズ群Ｇ１との間隔を縮める）し、第３レンズ群Ｇ３は開口絞りＳとともに物体側へのみ移動するようになっている。
また、第１レンズ群Ｇ１と第４レンズ群Ｇ４は、合焦動作時にも位置が固定されている。
非球面は、第１レンズ群Ｇ１中の物体側に凸面を向けた負メニスカスレンズＬ１₁の物体側の面、第３レンズ群Ｇ３中の両凸正レンズＬ３₁の両面、第４レンズ群Ｇ４を構成する両凸正レンズＬ４₁””の像側の面に設けられている。
【００９８】
次に、第６実施例のズームレンズを構成する光学部材の数値データを示す。

【００９９】

【０１００】

【０１０１】
第７実施例
図２２は本発明による電子撮像装置に用いるズームレンズの第７実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。図２３は第７実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【０１０２】
第７実施例の電子撮像装置は、図２２に示すように、物体側から順に、ズームレンズと、電子撮像素子であるＣＣＤを有している。図２２中、ＩはＣＣＤの撮像面である。ズームレンズと撮像面Ｉとの間には、平面平板状のＣＣＤカバーガラスＣＧが設けられている。
ズームレンズは、物体側から順に、第１レンズ群Ｇ１と、第１移動レンズ群である第２レンズ群Ｇ２と、開口絞りＳと、第２移動レンズ群である第３レンズ群Ｇ３と、第４レンズ群Ｇ４とを有している。
第１レンズ群Ｇ１は、物体側から順に、物体側に凸面を向けた負メニスカスレンズＬ１₁と、光路を折り曲げるための反射面を持つ反射光学素子Ｒ１と、物体側に凸面を向けた正メニスカスレンズＬ１₂’とで構成されている。
反射光学素子Ｒ１は、光路を９０°折り曲げる表面鏡として構成されている。また、表面鏡の反射面は形状可変に構成されており、反射面の形状を変化させることにより合焦動作を行うようになっている。
なお、本発明の各実施例における有効撮像領域の縦横比は３：４であり、折り曲げ方向は横方向である。
第２レンズ群Ｇ２は、物体側から順に、両凹負レンズＬ２₁と物体側に凸面を向けた正メニスカスレンズＬ２₂との接合レンズで構成されており、全体で負の屈折力を有している。
第３レンズ群Ｇ３は、物体側から順に、両凸正レンズＬ３₁と、両凸正レンズＬ３₂’と両凹負レンズＬ３₃’との接合レンズとで構成されており、全体で正の屈折力を有している。
第４レンズ群Ｇ４は、物体面側に凹面を向けた正メニスカスレンズＬ４₁で構成されている。
【０１０３】
広角端から望遠端へと変倍する際には、第１レンズ群Ｇ１及び第４レンズ群Ｇ４は位置が固定され、第２レンズ群Ｇ２は像側に凸状の軌跡で往復移動（即ち、像側へ移動して第１レンズ群Ｇ１との間隔を一旦広げた後、物体側へ移動しながら第１レンズ群Ｇ１との間隔を縮める）し、第３レンズ群Ｇ３は開口絞りＳとともに物体側へのみ移動するようになっている。
また、第１レンズ群Ｇ１と第４レンズ群Ｇ４は、合焦動作時にも位置が固定されている。
非球面は、第１レンズ群Ｇ１中の物体側に凸面を向けた負メニスカスレンズＬ１₁の像側の面、第３レンズ群Ｇ３中の両凹負レンズＬ３₃’の両面、第４レンズ群Ｇ４を構成する物体面側に凹面を向けた正メニスカスレンズＬ４₁の像側の面に設けられている。
【０１０４】
次に、第７実施例のズームレンズを構成する光学部材の数値データを示す。

【０１０５】

【０１０６】

【０１０７】
次に、上記実施例における条件式のパラメータ等の値を次の表に示す。

【０１０８】

【０１０９】
なお、本発明の各実施例では、いずれも、折り曲げ方向を上述のように電子撮像素子（ＣＣＤ）の長辺方向（水平方向）としている。垂直方向へ折り曲がるようにしたほうが、折り曲げのためのスペースが少なくて済み小型化には有利であるが、長辺方向への折り曲げに対応できるようにしておけば、長辺、短辺のいずれへの折り曲げにも対応でき、レンズを組み込むカメラデザインの自由度が増して好ましい。
また、上記各実施例では、ローパスフィルタは組み込んでいないが、ローパスフィルタを挿入して構成してもよい。また、電子撮像素子の水平画素ピッチａとしては、上記表以外に１．８から３．５までの値を用いてもよい。
なお、表中、折り曲げポイントは、上記レンズレータの仮想面前面（第３面）からの距離（４５度反射面と光軸上での距離）で示してある。
また、上記各実施例では、各数値データの反射面は無限物点合焦時に平面、近距離物点合焦時は凹面となる。
なお、形状可変の原理から無限遠物点合焦時においても、やや凹面にしておき、近距離物点合焦時にはさらに曲率の強い方向の凹面にするとよい。また、反射面の曲率半径は光軸との交点におけるものであり、非球面であってもよい。
【０１１０】
ここで、電子撮像素子の有効撮像面の対角長Ｌと画素間隔ａについて説明しておく。図２４は本発明の各実施例に用いる電子撮像素子の画素配列の一例を示す図であり、画素間隔ａでＲ（赤）、Ｇ（緑）、Ｂ（青）の画素あるいはシアン、マゼンダ、イエロー、グリーン（緑）の４色の画素（図２７）がモザイク状に配されている。有効撮像面は撮影した映像の再生（パソコン上での表示、プリンターによる印刷等）に用いる撮像素子上の光電変換面内における領域を意味する。図中に示す有効撮像面は、光学系の性能（光学系の性能が確保し得るイメージサークル）に合わせて、撮像素子の全光電変換面よりも狭い領域に設定されている。有効撮像面の対角長Ｌは、この有効撮像面の対角長である。なお、映像の再生に用いる撮像範囲を種々変更可能としてよいが、そのような機能を有する撮像装置に本発明のズームレンズを用いる際は、その有効撮像面の対角長Ｌが変化する。そのような場合は、本発明における有効撮像面の対角長Ｌは、とり得る範囲における最大値とする。
【０１１１】
なお、上記各実施例では、最終レンズ群の像側に近赤外カットフィルターを有するか、又は近赤外カットコートをＣＣＤカバーガラスＣＧの入射面側の表面、もしくは他のレンズの入射面側の面に施してある。また、ズームレンズの入射面から撮像面までの光路にローパスフィルターは配置していない。この近赤外カットフィルター、近赤外カットコート面は、波長６０ｎｍでの透過率が８０％以上、波長７００ｎｍでの透過率が１０％以下となるように構成されている。具体的には、例えば次のような２７層の層構成からなる多層膜である。ただし、設計波長は７８０ｎｍである。
【０１１２】

【０１１３】
上記の近赤外シャープカットコートの透過率特性は図２５に示す通りである。
また、近赤外カットコートを施したＣＣＤカバーガラスＣＧの射出面側、もしくは、近赤外カットコートを施した他のレンズの射出面側には、図２６に示すような短波長域の色の透過を低滅する色フィルターを設けるか、もしくは、コーティングを行うことで、より一層電子画像の色再現性を高めている。
具体的には、この近赤外カットフィルター、もしくは、近赤外カットコーティングにより、波長４００ｎｍ〜７００ｎｍで透過率が最も高い波長の透過率に対する４２０ｎｍの波長の透過率の比が１５％以上であり、その最も高い波長の透過率に対する４００ｎｍの波長の透過率の比が６％以下であることが好ましい。
それにより、人間の目の色に対する認識と、撮像及び再生される画像の色とのずれを低減させることができる。言い換えると、人間の視覚では認識され難い短波長側の色が、人間の目で容易に認識されることによる画像の劣化を防止することができる。
【０１１４】
上記の４００ｎｍの波長の透過率の比が６％を上回ると、人間の目では認識され難い単波長城が認識し得る波長に再生されてしまい、逆に、上記の４２０ｎｍの波長の透過率の比が１５％を下回ると、人間の認識し得る波長城の再生が、低くなり、色のバランスが悪くなる。
このような波長を制限する手段は、補色モザイクフィルターを用いた撮像系においてより効果を奏するものである。
【０１１５】
上記各実施例では、図２６に示すように、波長４００ｎｍにおける透過率が０％、波長４２０ｎｍにおける透過率が９０％、波長４４０ｎｍにおいて透過率のピーク１００％となるコーティングとしている。
そして、上述の近赤外シャープカットコートとの作用の掛け合わせにより、波長４５０ｎｍにおける透過率９９％をピークとして、波長４００ｎｍにおける透過率が０％、波長４２０ｎｍにおける透過率が８０％、波長６００ｎｍにおける透過率が８２％、波長７００ｎｍにおける透過率が２％となっている。それにより、より忠実な色再現を行っている。
【０１１６】
また、ＣＣＤの撮像面Ｉ上には、図２７に示す通り、シアン、マゼンダ、イエロー、グリーン（緑）の４色の色フィルターを撮像画素に対応してモザイク状に設けた補色モザイクフィルターを設けている。これら４種類の色フィルターは、それぞれが略同じ数になるように、かつ、隣り合う画素が同じ種類の色フィルターに対応しないようにモザイク状に配置されている。それにより、より忠実な色再現が可能となる。
【０１１７】
補色モザイクフィルターは、具体的には、図２７に示すように、少なくとも４種類の色フィルターから構成され、その４種類の色フィルターの特性は以下の通りであることが好ましい。
グリーンの色フィルターGは波長Ｇ_Pに分光強度のピークを有し、イエローの色フィルターＹ_eは波長Ｙ_Pに分光強度のピークを有し、シアンの色フィルターCは波長Ｃ_Pに分光強度のピークを有し、マゼンダの色フィルターＭは波長Ｍ_P1とＭ_P2にピークを有し、次の条件式を満足する。
５１０ｎｍ ＜ Ｇ_P ＜ ５４０ｎｍ
５ｎｍ ＜ Ｙ_P−Ｇ_P ＜ ３５ｎｍ
−１００ｎｍ ＜ Ｃ_P−Ｇ_P ＜ −５ｎｍ
４３０ｎｍ ＜ Ｍ_P1 ＜ ４８０ｎｍ
５８０ｎｍ ＜ Ｍ_P2 ＜ ６４０ｎｍ
【０１１８】
さらに、グリーン、イエロー、シアンの色フィルターはそれぞれの分光強度のピークに対して波長５３０ｎｍでは８０％以上の強度を有し、マゼンダの色フィルターはその分光強度のピークに対して波長５３０ｎｍでは１０％から５０％の強度を有することが、色再現性を高める上でより好ましい。
【０１１９】
上記各実施例におけるそれぞれの波長特性の一例を図２８に示す。グリーンの色フィルターＧは、波長５２５ｎｍに分光強度のビークを有している。イエローの色フィルターＹ_eは、波長５５５ｎｍに分光強度のピークを有している。シアンの色フィルターＣは、波長５１０ｎｍに分光強度のピークを有している。マゼンダの色フィルターＭは、波長４４５ｎｍと波長６２０ｎｍにピークを有している。また、波長５３０ｎｍにおける各色フィルターは、それぞれの分光強度のピークに対して、Ｇは９９％、Ｙ_eは９５％、Ｃは９７％、Ｍは３８％となっている。
【０１２０】
このような補色フィルターの場合、図示しないコントローラー（もしくは、デジタルカメラに用いられるコントローラー）で、電気的に次のような信号処理、即ち、
輝度信号
Ｙ＝｜Ｇ＋Ｍ＋Ｙ_e＋Ｃ｜×１／４
色信号
Ｒ−Ｙ＝｜（Ｍ＋Ｙ_e）−（Ｇ＋Ｃ）｜
Ｂ−Ｙ＝｜（Ｍ＋Ｃ）−（Ｇ＋Ｙ_e）｜
の信号処理を経て、Ｒ（赤）、Ｇ（緑）、Ｂ（青）の信号に変換される。
なお、上記した近赤外シャープカットコートの配置位置は、光路上のどの位置であってもよい。
【０１２１】
また、上記各実施例の数値データにおいて開口絞りＳの位置から次の像側のレンズの凸面までの間隔（ｄ₈）が０となっているのは、該レンズの凸面の面頂位置と、開口絞りＳから光軸へと下ろした垂線と光軸との交点とが等しいことを意味する。
なお、上記各実施例では絞りＳを平板としているが、他の構成として円形の開口を持った黒塗り部材を用いても良い。または、図２９に示すような漏斗状の絞りをレンズの凸面の傾きに沿ってかぶせても良い。さらには、レンズを保持する鏡枠において絞りを形成してもよい。
【０１２２】
また、上記各実施例においては、本発明における光量を調節するための透過率可変手段や受光時間を調節するためのシャッターを、第３レンズ群Ｇ３の像側の空気間隔に配置することができるように設計されている。
そして、光量調節手段に関しては、図３０に示すように、素通し面又は中空の開口、透過率１／２のＮＤフィルター、透過率１／４のＮＤフィルター等をターレット状に設けて構成したものを用いることができる。
【０１２３】
この具体例を図３１に示す。ただし、この図では便宜上、第１レンズ群Ｇ１〜第２レンズ群Ｇ２は省いて図示してある。第３レンズ群Ｇ３と第４レンズ群Ｇ４との間の光軸上の位置に、０段、−１段、−２段、−３段の明るさ調節を可能とする図３０に示すターレット１０を配置している。ターレット１０には、有効光束を透過する領域にて、各々波長５５０ｎｍに対する透過率について、透過率１００％の開口、透過率５０パーセントのＮＤフィルター、透過率２５％のＮＤフィルター、透過率１２．５％のＮＤフィルターが設けられた開口部１Ａ，１Ｂ，１Ｃ，１Ｄを有している。
そして、ターレット１０の回転軸１１の周りの回動により、いずれかの開口を絞り位置とは異なる空間であるレンズ間の光軸上に配置することで光量調節を行っている。
【０１２４】
また、光量調節手段として、図３２に示すように、光量ムラを抑えるように、光量調節が可能なフィルター面を設けても良い。図３２のフィルター面は、同心円状に透過率が異なり、中心にいくほど光量が低下するようになっている。
そして、上記フィルター面を配置することにより、暗い被写体に対しては中心部の光量確保を優先して透過率を均一とし、明るい被写体に対してのみ明るさムラを補うように構成してもよい。
【０１２５】
さらには、装置全体の薄型化を考慮すると、電気的に透過率を制御できる電気光学素子を用いることが出来る。
電気光学素子は、たとえば、図３３に示すように、ＴＮ液晶セルを透明電極と偏光方向を一致させた偏光膜を持つ２枚の平行平板で両側から挟み込み、透明電極間の電圧を適宜かえることにより液晶の内での偏光方向を変化させて透過する光量を調節する液晶フィルター等で構成できる。
なお、この液晶フィルターでは、可変抵抗を介してＴＮ液晶セルにかかる電圧を調整して、ＴＮ液晶セルの配向を変化させている。
【０１２６】
さらには、光量調節手段として、上述のような透過率を調節する各種フィルターにかえて受光時間を調節するシャッターを設けても良い。又はシャッターをフィルターと併設させても良い。
シャッターは像面近傍に配置した移動幕によるフォーカルプレーンシャッターで構成しても良いし、光路途中に設けた２枚羽のレンズシャッター、フォーカルプレーンシャッター、液晶シャッター等、種々のもので構成しても構わない。
【０１２７】
図３４は本発明の各実施例にかかる電子撮像装置に適用可能な受光時間を調節するフォーカルプレーンシャッターの1つであるロータリーフォーカルプレーンシャッターの一例を示す概略構成図であり、(a)は裏面図、(b)は表面図、図３５(a)〜(d)はロータリーシャッター幕Ｂが回転する様子を像面側からみた図である。
図３４中、Ａはシャッター基板、Ｂはロータリーシャッター幕、Ｃはロータリーシャッター幕の回転軸、Ｄ１，Ｄ２はギアである。
【０１２８】
シャッター基板Ａは、本発明の電子撮像装置において、像面の直前、または任意の光路に配置される構成となっている。また、シャッター基板Ａには、光学系の有効光束を透過する開口部Ａ１が設けられている。ロータリーシャッター幕Ｂは略半円型に形成されている。ロータリーシャッター幕の回転軸Ｃは、ロータリーシャッター幕Ｂと一体化されている。また、回転軸Ｃは、シャッター基板Ａに対して回転するようになっている。また、回転軸Ｃは、シャッター基板Ａの表面のギアＤ１，Ｄ２と連結されている。ギアＤ１，Ｄ２は図示しないモーターと連結されている。
そして、図示しないモーターの駆動により、ギアＤ２，Ｄ１、回転軸Ｃを介してロータリーシャッター幕Ｂが回転軸Ｃを中心に、時間を追って図３５(a)〜(d)の順で回転するようになっている。ロータリーシャッター幕Ｂは、回転により、シャッター基板Ａの開口部Ａ１の遮蔽と退避を行いシャッターとしての役割を果たしている。
また、シャッタースピードはロータリーシャッター幕Ｂの回転するスピードを変えることで調整されるようになっている。
【０１２９】
以上、光量調節手段について説明したが、これらのシャッター、透過率可変フィルターは、上述の本発明の実施例においては、例えば、第１実施例の第１６面に配置される。なお、これらの光量調節手段は、上述の開口絞りとは異なる位置であれば、他の位置に配置しても良い。
【０１３０】
また、上述の電気光学素子に、シャッターの役割を兼用させても良い。このようにすると、部品点数の削減、光学系の小型化の点でより好ましい。
【０１３１】
次に、本発明のズームレンズにおける光路折り曲げ用の反射面を持つ反射光学素子として適用可能な可変ミラーの構成例について説明する。
図３６は本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９の一実施例を示す概略構成図である。
まず、光学特性可変形状鏡４０９の基本構成について説明する。
【０１３２】
可変形状鏡４０９は、アルミコーティング等で作られた薄膜（反射面）４０９ａと複数の電極４０９ｂを有してなる光学特性可変形状鏡（以下、単に可変形状鏡と言う。）であり、４１１は各電極４０９ｂにそれぞれ接続された複数の可変抵抗器、４１４は複数の可変抵抗器４１１の抵抗値を制御するための演算装置、４１５，４１６及び４１７はそれぞれ演算装置４１４に接続された温度センサー、湿度センサー及び距離センサーで、これらは図示のように配設されて１つの光学装置を構成している。
【０１３３】
可変形状鏡の面は、平面でなくてもよく、球面、回転対称非球面の他、光軸に対して偏心した球面、平面、回転対称非球面、あるいは、対称面を有する非球面、対称面を１つだけ有する非球面、対称面のない非球面、自由曲面、微分不可能な点又は線を有する面等、いかなる形状をしていてもよく、さらに、反射面でも屈折面でも光に何らかの影響を与え得る面ならばよい。以下、これらの面を総称して拡張曲面という。
【０１３４】
なお、可変形状鏡の反射面の形状は、自由曲面に構成するのがよい。なぜなら、収差補正が容易にでき、有利だからである。
また、本発明で使用する自由曲面とは以下の式で定義されるものである。この定義式のＺ軸が自由曲面の軸となる。
【０１３５】

ここで、（ａ）式の第１項は球面項、第２項は自由曲面項である。Ｍは２以上の自然数である。
球面項中、
ｃ：頂点の曲率
ｋ：コーニック定数（円錐定数）
ｒ＝√（Ｘ² ＋Ｙ² ）
である。
【０１３６】
自由曲面項は、

ただし、Ｃj （ｊは２以上の整数）は係数である。
上記自由曲面は、一般的には、Ｘ−Ｚ面、Ｙ−Ｚ面共に対称面を持つことはないが、Ｘの奇数次項を全て０にすることによって、Ｙ−Ｚ面と平行な対称面が１つだけ存在する自由曲面となる。また、Ｙの奇数次項を全て０にすることによって、Ｘ−Ｚ面と平行な対称面が１つだけ存在する自由曲面となる。
【０１３７】
本実施例の可変形状鏡は、図３６に示すように、薄膜４０９ａと電極４０９ｂとの間に圧電素子４０９ｃが介装されていて、これらが支持台４２３上に設けられている。そして、圧電素子４０９ｃに加わる電圧を各電極４０９ｂ毎に変えることにより、圧電素子４０９ｃに部分的に異なる伸縮を生じさせて、薄膜４０９ａの形状を変えることができるようになっている。電極４０９ｂの形は、図３７に示すように、同心分割であってもよいし、図３８に示すように、矩形分割であってもよく、その他、適宜の形のものを選択することができる。図３６中、４２４は演算装置４１４に接続された振れ（ブレ）センサーであって、例えばデジタルカメラの振れを検知し、振れによる像の乱れを補償するように薄膜４０９ａを変形させるべく、演算装置４１４及び可変抵抗器４１１を介して電極４０９ｂに印加される電圧を変化させる。このとき、温度センサー４１５、湿度センサー４１６及び距離センサー４１７からの信号も同時に考慮され、ピント合わせ、温湿度補償等が行われる。この場合、薄膜４０９ａには圧電素子４０９ｃの変形に伴う応力が加わるので、薄膜４０９ａの厚さはある程度厚めに作られて相応の強度を持たせるようにするのがよい。
【０１３８】
図３９は本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。
本実施例の可変形状鏡は、薄膜４０９ａと電極４０９ｂの間に介置される圧電素子が逆方向の圧電特性を持つ材料で作られた２枚の圧電素子４０９ｃ及び４０９ｃ’で構成されている点で、図３６に示された実施例の可変形状鏡とは異なる。すなわち、圧電素子４０９ｃと４０９ｃ’が強誘電性結晶で作られているとすれば、結晶軸の向きが互いに逆になるように配置される。この場合、圧電素子４０９ｃと４０９ｃ’は電圧が印加されると逆方向に伸縮するので、薄膜４０９ａを変形させる力が図３６に示した実施例の場合よりも強くなり、結果的にミラー表面の形を大きく変えることができるという利点がある。
【０１３９】
圧電素子４０９ｃ，４０９ｃ’に用いる材料としては、例えばチタン酸バリウム、ロッシエル塩、水晶、電気石、リン酸二水素カリウム（ＫＤＰ）、リン酸二水素アンモニウム（ＡＤＰ）、ニオブ酸リチウム等の圧電物質、同物質の多結晶体、同物質の結晶、ＰｂＺｒＯ₃とＰｂＴｉＯ₃の固溶体の圧電セラミックス、二フッ化ポリビニール（ＰＶＤＦ）等の有機圧電物質、上記以外の強誘電体等があり、特に有機圧電物質はヤング率が小さく、低電圧でも大きな変形が可能であるので、好ましい。なお、これらの圧電素子を利用する場合、厚さを不均一にすれば、上記実施例において薄膜４０９ａの形状を適切に変形させることも可能である。
【０１４０】
また、圧電素子４０９ｃ，４０９ｃ’の材質としては、ポリウレタン、シリコンゴム、アクリルエラストマー、ＰＺＴ、ＰＬＺＴ、ポリフッ化ビニリデン（ＰＶＤＦ）等の高分子圧電体、シアン化ビニリデン共重合体、ビニリデンフルオライドとトリフルオロエチレンの共重合体等が用いられる。
圧電性を有する有機材料や、圧電性を有する合成樹脂、圧電性を有するエラストマー等を用いると可変形状鏡面の大きな変形が実現できてよい。
【０１４１】
なお、図３６、図４０の圧電素子４０９ｃに電歪材料、例えば、アクリルエラストマー、シリコンゴム等を用いる場合には、圧電素子４０９ｃを別の基板４０９ｃ−１と電歪材料４０９ｃ−２を貼り合わせた構造にしてもよい。
【０１４２】
図４０は本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。
本実施例の可変形状鏡は、圧電素子４０９ｃが薄膜４０９ａと電極４０９ｄとにより挟持され、薄膜４０９ａと電極４０９ｄ間に演算装置４１４により制御される駆動回路４２５を介して電圧が印加されるようになっており、さらにこれとは別に、支持台４２３上に設けられた電極４０９ｂにも演算装置４１４により制御される駆動回路４２５を介して電圧が印加されるように構成されている。したがって、本実施例では、薄膜４０９ａは電極４０９ｄとの間に印加される電圧と電極４０９ｂに印加される電圧による静電気力とにより二重に変形され得、上記実施例に示した何れのものよりもより多くの変形パターンが可能であり、かつ、応答性も速いという利点がある。
【０１４３】
そして、薄膜４０９ａ、電極４０９ｄ間の電圧の符号を変えれば、可変形状鏡を凸面にも凹面にも変形させることができる。その場合、大きな変形を圧電効果で行ない、微細な形状変化を静電気力で行なってもよい。また、凸面の変形には圧電効果を主に用い、凹面の変形には静電気力を主に用いてもよい。なお、電極４０９ｄは電極４０９ｂのように複数の電極から構成されてもよい。この様子を図４０に示した。なお、本願では、圧電効果と電歪効果、電歪をすべてまとめて圧電効果と述べている。従って、電歪材料も圧電材料に含むものとする。
【０１４４】
図４１は本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。
本実施例の可変形状鏡は、電磁気力を利用して反射面の形状を変化させ得るようにしたもので、支持台４２３の内部底面上には永久磁石４２６が、頂面上には窒化シリコン又はポリイミド等からなる基板４０９ｅの周縁部が載置固定されており、基板４０９ｅの表面にはアルミニウム等の金属コートで作られた薄膜４０９ａが付設されていて、可変形状鏡４０９を構成している。基板４０９ｅの下面には複数のコイル４２７が配設されており、これらのコイル４２７はそれぞれ駆動回路４２８を介して演算装置４１４に接続されている。したがって、各センサー４１５，４１６，４１７，４２４からの信号によって演算装置４１４において求められる光学系の変化に対応した演算装置４１４からの出力信号により、各駆動回路４２８から各コイル４２７にそれぞれ適当な電流が供給されると、永久磁石４２６との間に働く電磁気力で各コイル４２７は反発又は吸着され、基板４０９ｅ及び薄膜４０９ａを変形させる。
【０１４５】
この場合、各コイル４２７はそれぞれ異なる量の電流を流すようにすることもできる。また、コイル４２７は１個でもよいし、永久磁石４２６を基板４０９ｅに付設しコイル４２７を支持台４２３の内部底面側に設けるようにしてもよい。また、コイル４２７はリソグラフィー等の手法で作るとよく、さらに、コイル４２７には強磁性体よりなる鉄心を入れるようにしてもよい。
【０１４６】
この場合、薄膜コイル４２７の巻密度を、図４２に示すように、場所によって変化させることにより、基板４０９ｅ及び薄膜４０９ａに所望の変形を与えるようにすることもできる。また、コイル４２７は１個でもよいし、また、これらのコイル４２７には強磁性体よりなる鉄心を挿入してもよい。
【０１４７】
図４３は本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。図中、４１２は電源である。
本実施例の可変形状鏡では、基板４０９ｅは鉄等の強磁性体で作られており、反射膜としての薄膜４０９ａはアルミニウム等からなっている。この場合、薄膜コイルを設けなくてもすむから、構造が簡単で、製造コストを低減することができる。また、電源スイッチ４１３を切換え兼電源開閉用スイッチに置換すれば、コイル４２７に流れる電流の方向を変えることができ、基板４０９ｅ及び薄膜４０９ａの形状を自由に変えることができる。図４４は本実施例におけるコイル４２７の配置を示し、図４５はコイル４２７の他の配置例を示しているが、これらの配置は、図４１に示した実施例にも適用することができる。なお、図４６は、図４１に示した実施例において、コイル４２７の配置を図４５に示したようにした場合に適する永久磁石４２６の配置を示している。すなわち、図４６に示すように、永久磁石４２６を放射状に配置すれば、図４１に示した実施例に比べて、微妙な変形を基板４０９ｅ及び薄膜４０９ａに与えることができる。また、このように電磁気力を用いて基板４０９ｅ及び薄膜４０９ａを変形させる場合（図４１及び図４３の実施例）は、静電気力を用いた場合よりも低電圧で駆動できるという利点がある。
【０１４８】
以上いくつかの可変形状鏡の実施例を述べたが、ミラーの形を変形させるのに、図４０の例に示すように、２種類以上の力を用いてもよい。つまり静電気力、電磁力、圧電効果、磁歪、流体の圧力、電場、磁場、温度変化、電磁波等のうちから２つ以上を同時に用いて可変形状鏡を変形させてもよい。つまり２つ以上の異なる駆動方法を用いて光学特性可変光学素子を作れば、大きな変形と微細な変形とを同時に実現でき、精度の良い鏡面が実現できる。
【０１４９】
図４７は本発明のさらに他の実施例に係る、ズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９を用いた撮像系、例えば携帯電話のデジタルカメラ、カプセル内視鏡、電子内視鏡、パソコン用デジタルカメラ、ＰＤＡ用デジタルカメラ等に用いられる撮像系の概略構成図である。
本実施例の撮像系は、第１実施例で示した光学構成における反射光学素子Ｒ１を可変形状鏡４０９で構成したものである。そして、これらのズームレンズと、電子撮像素子であるＣＣＤ４０８と、制御系１０３とで一つの撮像ユニット１０４を構成している。本実施例の撮像ユニット１０４では、物体側に凸面を向けた負メニスカスレンズＬ１₁を通った物体からの光は、可変形状鏡４０９で集光され、両凸正レンズＬ１₂、第２レンズ群Ｇ２、第３レンズ群Ｇ３、第４レンズ群Ｇ４、ＣＣＤカバーガラスＣＧを経て、固体撮像素子であるＣＣＤ４０８の上に結像する。この可変形状鏡４０９は、光学特性可変光学素子の一種であり、可変焦点ミラーとも呼ばれている。
【０１５０】
本実施例によれば、物体距離が変わっても可変形状鏡４０９を変形させることでピント合わせをすることができ、レンズをモータ等で駆動する必要がなく、小型化、軽量化、低消費電力化の点で優れている。また、撮像ユニット１０４は本発明の撮像系としてすべての実施例で用いることができる。また、可変形状鏡４０９を複数用いることでズーム、変倍の撮像系、光学系を作ることができる。
なお、図４７では、制御系１０３にコイルを用いたトランスの昇圧回路を含む制御系の構成例を示している。特に積層型圧電トランスを用いると、小型化できてよい。昇圧回路は本発明のすべての電気を用いる可変形状鏡に用いることができるが、特に静電気力、圧電効果を用いる場合の可変形状鏡に有用である。なお、可変形状鏡４０９でピント合わせを行なう為には、例えば固体撮像素子４０８に物体像を結像させ、可変形状鏡４０９の焦点距離を変化させながら物体像の高周波成分が最大になる状態を見つければよい。高周波成分を検出するには、固体撮像素子４０８にマイクロコンピュータ等を含む処理回路を接続し、その中で高周波成分を検出すればよい。
【０１５１】
さて、以上のような本発明の折り曲げズームレンズを用いた電子撮像装置は、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、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。
【０１５２】
図４８〜図５０は本発明による折り曲げズームレンズ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であり、図４８はデジタルカメラ４０の外観を示す前方斜視図、図４９は同後方斜視図、図５０はデジタルカメラ４０の構成を示す断面図である。なお、図５０に示すデジタルカメラは、撮像光路をファインダーの長辺方向に折り曲げた構成となっており、図５０中の観察者の眼を上側からみて示してある。
【０１５３】
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、第１実施例の光路折り曲げズームレンズを通して撮影が行われるようになっている。
そして、撮影光学系４１によって形成された物体像が、近赤外カットフィルター、又はＣＣＤカバーガラス又はその他のレンズに施された近赤外カットコートを経てＣＣＤ４９の撮像面上に形成される。
【０１５４】
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（登録商標）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。
【０１５５】
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。
【０１５６】
このように構成されたデジタルカメラ４０は、長辺方向に光路を置き曲げたことによりカメラの薄型化に効果がある。また、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。
なお、本実施例のデジタルカメラ４０の撮像光路をファインダーの短辺方向に折り曲げて構成してもよい。その場合には、撮影レンズの入射面からストロボ（又はフラッシュ）をより上方に離して配置し、人物のストロボ撮影時の際に生じる影の影響を緩和できるレイアウトにし得る。
また、図５０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。
【０１５７】
次に、本発明の折り曲げズームレンズ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を図５１〜図５３に示す。図５１はパソコン３００のカバーを開いた前方斜視図、図５２はパソコン３００の撮影光学系３０３の断面図、図５３は図５１の側面図である。
【０１５８】
図５１〜図５３に示すように、パソコン３００は、外部から操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。
この撮影光学系３０３は、撮影光路３０４上に、本発明による例えば第１実施例の光路折り曲げズームレンズ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。
【０１５９】
ここで、撮像素子チップ１６２上にはカバーガラスＣＧ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。
【０１６０】
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５１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。
【０１６１】
次に、本発明の折り曲げズームレンズ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を図５４に示す。図５４(a)は携帯電話４００の正面図、図５４(b)は側面図、図５４(c)は撮影光学系４０５の断面図である。
図５４(a)〜(c)に示すように、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例えば第１実施例の光路折り曲げズームレンズ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。
【０１６２】
ここで、撮像素子チップ１６２上にはカバーガラスＣＧ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。
【０１６３】
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。
【０１９９】
【発明の効果】
本発明によれば、極力物体側にミラーなど反射光学素子を挿入して光学系特にズームレンズ系の光路（光軸）を折り曲げる構成とし、さらに諸々の条件式等を満たすように構成したので、ズーム比、画角、Ｆ値、少ない収差など高い光学仕様性能を確保しながらも、沈胴式鏡筒に見られるようなカメラの使用状態への立ち上げ時間（レンズのせり出し時間）がなく、防水・防塵上も好ましく、また、奥行き方向が極めて薄いカメラを実現することができる。加えて、沈胴式鏡筒に適したズームレンズなど他のズーム光学系と異なり、今後、撮像素子の小型化が進んだ場合に、その小形化された撮像素子を使用する場合におけるカメラのさらなる小型化、薄型化を有利に進めることができる。
【図面の簡単な説明】
【図１】本発明による電子撮像装置に用いるズームレンズの第１実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。
【図２】第１実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【図３】第１実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、広角端での状態を示している。
【図４】第１実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、中間での状態を示している。
【図５】第１実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、望遠端での状態を示している。
【図６】本発明による電子撮像装置に用いるズームレンズの第２実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。
【図７】第２実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【図８】本発明による電子撮像装置に用いるズームレンズの第３実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。
【図９】第３実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【図１０】第３実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、広角端での状態を示している。
【図１１】第３実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、中間での状態を示している。
【図１２】第３実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、望遠端での状態を示している。
【図１３】本発明による電子撮像装置に用いるズームレンズの第４実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。
【図１４】第４実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【図１５】第４実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、広角端での状態を示している。
【図１６】第４実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、中間での状態を示している。
【図１７】第４実施例にかかるズームレンズの無限遠物点合焦時における球面収差、非点収差、歪曲収差、倍率色収差を示す図であり、望遠端での状態を示している。
【図１８】本発明による電子撮像装置に用いるズームレンズの第５実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。
【図１９】第５実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【図２０】本発明による電子撮像装置に用いるズームレンズの第６実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。
【図２１】第６実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【図２２】本発明による電子撮像装置に用いるズームレンズの第７実施例にかかる光学構成を示す光軸に沿う断面図であり、広角端無限遠物点合焦時の折り曲げ時における状態を示している。
【図２３】第７実施例にかかるズームレンズの無限遠物点合焦時の光学構成を示す光軸に沿う断面図であり、(a)は広角端、(b)は中間、(c)は望遠端での状態を示している。
【図２４】本発明の各実施例に用いる電子撮像素子の画素配列の一例を示す説明図である。
【図２５】近赤外シャープカットコートの一例の透過率特性を示すグラフである。
【図２６】近赤外カットコートを施したＣＣＤカバーガラスＣＧの射出面側、もしくは、近赤外カットコートを施した他のレンズの射出面側に設ける色フィルターの一例の透過率特性を示すグラフである。
【図２７】補色モザイクフィルターの色フィルター配置を示す図である。
【図２８】補色モザイクフィルターの波長特性の一例を示すグラフである。
【図２９】本発明の各実施例にかかる電子撮像装置に用いる絞りＳの変形例を示す説明図である。
【図３０】本発明の各実施例にかかる電子撮像装置に用いる光量調節手段の一例を示す説明図である。
【図３１】図３０に示した光量調節手段を本発明に適用した状態の具体例を示す斜視図である。
【図３２】本発明の各実施例にかかる電子撮像装置に適用可能な光量調節手段の他の例を示す説明図である。
【図３３】本発明の各実施例にかかる電子撮像装置に適用可能な光量調節手段のさらに他の例を示す説明図である。
【図３４】本発明の各実施例にかかる電子撮像装置に適用可能な受光時間を調節するフォーカルプレーンシャッターの1つであるロータリーフォーカルプレーンシャッターの一例を示す概略構成図であり、(a)は裏面図、(b)は表面図である。
【図３５】 (a)〜(d)は図３４に示したロータリーシャッター幕Ｂが回転する様子を像面側からみた図である。
【図３６】本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９の一実施例を示す概略構成図である。
【図３７】図３６の実施例の可変形状鏡に用いる電極の一形態を示す説明図である。
【図３８】図３６の実施例の可変形状鏡に用いる電極の他の形態を示す説明図である。
【図３９】本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。
【図４０】本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。
【図４１】本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。
【図４２】図４１の実施例における薄膜コイル４２７の巻密度の状態を示す説明図である。
【図４３】本発明のズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９のさらに他の実施例を示す概略構成図である。
【図４４】図４３の実施例におけるコイル４２７の一配置例を示す説明図である。
【図４５】図４３の実施例におけるコイル４２７の他の配置例を示す説明図である。
【図４６】図４１に示した実施例において、コイル４２７の配置を図４５に示したようにした場合に適する永久磁石４２６の配置を示す説明図である。
【図４７】本発明のさらに他の実施例に係る、ズームレンズの折り曲げ用の反射面を持つ反射光学素子として適用可能な可変形状鏡４０９を用いた撮像系、例えば携帯電話のデジタルカメラ、カプセル内視鏡、電子内視鏡、パソコン用デジタルカメラ、ＰＤＡ用デジタルカメラ等に用いられる撮像系の概略構成図である。
【図４８】本発明による折り曲げズームレンズ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であり、デジタルカメラ４０の外観を示す前方斜視図である。
【図４９】図４８に示したデジタルカメラ４０の後方斜視図である。
【図５０】図４８に示したデジタルカメラ４０の構成を示す断面図である。
【図５１】本発明の折り曲げズームレンズ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３００のカバーを開いた前方斜視図である。
【図５２】図５１に示したパソコン３００の撮影光学系３０３の断面図である。
【図５３】図５１の側面図である。
【図５４】本発明の折り曲げズームレンズ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携帯電話を示す図であり、(a)は携帯電話４００の正面図、(b)は(a)の側面図、(c)は撮影光学系４０５の断面図である。
【符号の説明】
Ａ シャッター基板
Ａ１ 基板の開口部
Ｂ ロータリーシャッター幕
Ｃ ロータリーシャッター幕の回転軸
Ｄ１，Ｄ２ ギア
ＣＧ ＣＣＤカバーガラス
Ｅ 観察者眼球
Ｇ１ 第１レンズ群
Ｇ２ 第２レンズ群（第１移動レンズ群）
Ｇ３ 第３レンズ群（第２移動レンズ群）
Ｇ４ 第４レンズ群
Ｉ 撮像面
Ｌ１₁ 物体側に凸面を向けた負メニスカスレンズ
Ｌ１₂ 両凸正レンズ
Ｌ２₁ 両凹負レンズ
Ｌ２₂ 物体側に凸面を向けた正メニスカスレンズ
Ｌ３₁ 両凸正レンズ
Ｌ３₂ 両凹負レンズ
Ｌ３₂’ 両凸正レンズ
Ｌ３₃ 物体側に凸面を向けた正メニスカスレンズ
Ｌ３₃’ 両凹負レンズ
Ｌ４₁ 物体側に凹面を向けた正メニスカスレンズ
Ｌ４₁’ 両凹負レンズ
Ｌ４₁” 物体側に凸面を向けた負メニスカスレンズ
Ｌ４₁”’ 物体側に凸面を向けた正メニスカスレンズ
Ｌ４₁”” 両凸正レンズ
Ｌ４₂ 両凸正レンズ
Ｒ１ 反射光学素子
Ｓ 開口絞り
１Ａ，１Ｂ，１Ｃ，１Ｄ 開口
１０ ターレット
１１ 回転軸
４０ デジタルカメラ
４１ 撮像光学系
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
１０３ 制御系
１０４ 撮像ユニット
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
４０８ 固体撮像素子
４０９ｂ，４０９ｄ 電極
４０９ｃ−２ 電歪材料
４０９ 光学特性可変形状鏡
４０９ａ 薄膜
４０９ｃ，４０９ｃ’ 圧電素子
４０９ｃ−１，４０９ｅ 基板
４１１ 可変抵抗器
４１２ 電源
４１３ 電源スイッチ
４１４ 演算装置
４１５ 温度センサー
４１６ 湿度センサー
４１７ 距離センサー
４２３ 支持台
４２４ 振れセンサー
４２５，４２８ 駆動回路
４２６ 永久磁石
４２７ コイル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a zoom lens and an electronic image pickup apparatus having the same, and more particularly to an electronic image pickup apparatus such as a video camera and a digital camera that have been thinned in the depth direction by devising an optical system part such as a zoom lens and the like. The present invention relates to a zoom lens.
[0002]
[Prior art]
In recent years, a digital camera (electronic camera) has attracted attention as a next-generation camera that replaces a silver salt 35 mm film (135 format) camera. Furthermore, it has come to have a number of categories in a wide range from a high-function type for business use to a portable popular type.
In the present invention, focusing on the portable popular type category, it is aimed to provide a technology for realizing a video camera and a digital camera that are thin and easy to use while ensuring high image quality.
[0003]
The biggest bottleneck in reducing the depth direction of the camera is the thickness from the most object-side surface to the imaging surface of the optical system, particularly the zoom lens system.
The mainstream of the recent camera body thinning technology is to employ a so-called collapsible lens barrel that has an optical system that protrudes from the camera body at the time of photographing, but is housed when it is carried.
Examples of optical systems that can be effectively thinned by employing a retractable lens barrel are disclosed in JP-A-11-194274, JP-A-11-287953, JP-A-2000-9997, and the like. There is a description. These have a first group having a negative refractive power and a second group having a positive refractive power in order from the object side, and both the first group and the second group move during zooming.
[0004]
[Problems to be solved by the invention]
However, if a retractable lens barrel is employed, it takes time to start from the lens storage state to the use state, which is not preferable in terms of convenience. Further, if the lens group closest to the object is movable, it is not preferable in terms of waterproofing and dustproofing. In addition, there is a physical restriction of the processing limit size in the thickness direction of the lens component, and the size of the retractable lens barrel is determined by the thickness of the lens component, so further downsizing of the image sensor will be realized in the future Even so, it cannot be expected that the camera will be thinner in the depth direction.
[0005]
On the other hand, there is no time to start up the camera (lens protruding time) as seen in a retractable lens barrel, it is waterproof and dustproof, and the depth direction is very thin. A configuration is also conceivable in which the optical path (optical axis) of the system is bent by a reflective optical element such as a mirror. In this case, even if the depth direction can be reduced, the entire length of the optical path after bending is increased, and therefore dimensions other than the depth tend to be increased. However, it can be expected that the structure for bending the optical path can be made thinner in proportion to the further downsizing of the imaging device. However, on the other hand, it is necessary to consider the influence of diffraction due to the downsizing of the image sensor.
[0006]
The present invention has been made in view of such problems of the prior art, and its object is to eliminate the time for starting up the camera (the lens protruding time) as seen in a retractable lens barrel. It is also preferable in terms of waterproofing and dustproofing, can be a camera with a very thin depth direction, and the drive mechanism is simple and easy to miniaturize, making it easy to reduce in proportion to future miniaturization of the image sensor. An object of the present invention is to provide a zoom lens and an electronic imaging apparatus having the same.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, the zoom lens according to the first aspect of the present invention is located closest to the object side, and is fixed on the optical axis at the time of zooming and focusing, and is positioned closest to the image side. Located at least between the most image side lens group that is fixed on the optical axis during focusing operation, and between the most object side lens group and the most image side lens group, and moves on the optical axis during zooming A first moving lens group and a second moving lens group;Consist of,The most object side lens group has a positive refractive power, the first moving lens group has a negative refractive power, the second moving lens group has a positive refractive power, and the most image side lens group has a positive refractive power. AndThe most object side lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending the optical path, and a positive lens component, and the most image side lens group includes at least one non-lens group. It has a spherical surface and satisfies the following conditional expression.
      0.9 <−f11 / √ (fw · fT) <2.4
      1.6 <f12 / √ (fw · fT) <3.6
  Where f11 is the focal length of the negative lens component in the most object side lens group, f12 is the focal length of the positive lens component in the most object side lens group, and fw is the focal length of the entire system at the wide angle end of the zoom lens. , FT is the focal length of the entire system at the telephoto end of the zoom lens.
[0008]
  Further, the zoom lens according to the second aspect of the invention is in order from the object side.Has positive refractive power,A first lens group that is a fixed most object side lens group at the time of zooming, a second lens group that has a negative refractive power and moves on the optical axis at the time of zooming, and a positive lens A third lens group as a second moving lens group having refractive power and moving on the optical axis at the time of zooming;Has positive refractive power,The most image side lens group arranged closest to the image side,Consist ofThe first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending an optical path, and a positive lens component, and the reflecting surface is variable in shape, It satisfies the conditional expression.
      0.9 <−f11 / √ (fw · fT) <2.4
      1.6 <f12 / √ (fw · fT) <3.6
  Where f11 is the focal length of the negative lens component in the most object side lens group, f12 is the focal length of the positive lens component in the most object side lens group, and fw is the focal length of the entire system at the wide angle end of the zoom lens. , FT is the focal length of the entire system at the telephoto end of the zoom lens.
[0009]
  The zoom lens according to the third invention isIn the second invention,When zooming from the wide-angle end to the telephoto end at the time of focusing on an object point at infinity, the second lens group reciprocates on the optical axis along a convex locus on the image side.
[0010]
The zoom lens according to the fourth invention is characterized in that, in any of the first to third inventions, a focusing operation is performed by changing the shape of the reflecting surface.
[0011]
The zoom lens according to the fifth invention is the zoom lens according to any one of the first to fourth inventions, wherein the reflecting surface is formed of a thin film coated with a metal or a dielectric, and the thin film includes a plurality of electrodes. And an arithmetic unit that is connected to a power source via a variable resistor and controls the variable resistance value of the variable resistor, and the shape of the reflecting surface is variable by controlling the distribution of electrostatic force applied to the thin film. It is characterized by comprising.
[0012]
  In the electronic imaging device according to the sixth invention, in any one of the second to fifth inventions, the third lens group includes three lenses, and the three lenses are positive lenses. Consists of a cemented lens component that joins a negative lens and two lens components of a single lens, or a single lens component that consists of three cemented lenses, and zooms from the wide-angle end to the telephoto end. When moving, it moves only to the object side.
  The zoom lens according to the seventh invention is the zoom lens according to any one of the first and second inventions, wherein the negative lens component in the most object side lens group is a negative single lens, and the positive lens component is positive. It is characterized by comprising a single lens.
  Further, in the zoom lens according to the eighth invention, in the third invention, the first lens group has a positive refractive power, and the third lens group moves only to the object side at the time of zooming, The most image side lens group includes an aspherical surface and is fixed at the time of zooming.
  The zoom lens according to the ninth invention is characterized in that, in any one of the second to fourth inventions, the following conditional expression is satisfied.
      0.3 <−βRw <0.8
      0.8 <fRw / √ (fw · fT) <2.0
  Where βRw is the combined magnification after the third lens group at the wide-angle end when focusing on an object point at infinity, and fRw is the combined focal length after the third lens group at the wide-angle end when focusing on an object point at infinity. , Fw is the focal length of the entire system at the wide-angle end of the zoom lens, and fT is the focal length of the entire system at the telephoto end of the zoom lens.
  The zoom lens according to the tenth aspect of the present invention is the zoom lens according to any one of the second to sixth aspects, wherein the third lens group is composed of three lenses, and the three lenses are arranged from the object side. In order, the lens is composed of a single lens and a cemented lens component obtained by cementing a positive lens and a negative lens.
  In the zoom lens according to the eleventh invention, in any one of the second to sixth inventions, the third lens group includes three lenses, and the three lenses are arranged from the object side. It is characterized by comprising a cemented lens component in which a positive lens and a negative lens are cemented in order and a single lens.
  The zoom lens according to the twelfth aspect of the present invention is the zoom lens according to any one of the second to sixth aspects of the present invention, wherein the third lens group includes three lenses, and the three lenses are arranged from the object side. It is characterized by comprising, in order, a three-piece cemented lens component in which a positive lens, a negative lens, and a positive lens are cemented.
  The zoom lens according to the thirteenth aspect of the invention is characterized in that, in the tenth aspect of the invention, the following conditional expression is satisfied.
      0.4 <R_C3/ R_C1  <0.8
  However, R_C3Is the radius of curvature on the optical axis of the most image side surface of the cemented lens component in the third lens group, R_C1Is a radius of curvature of the cemented lens component in the third lens group on the optical axis of the most object side surface.
  In the zoom lens according to the fourteenth aspect of the invention, in order from the object side,Has positive refractive power,A first lens group that is a fixed most object side lens group at the time of zooming, a second lens group that has a negative refractive power and moves on the optical axis at the time of zooming, and a positive lens A third lens group as a second moving lens group having refractive power and moving on the optical axis at the time of zooming;Has positive refractive power,The most image side lens group arranged closest to the image side,Consist ofThe first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending an optical path, and a positive lens component, and the reflecting surface is variable in shape, The three lens group is composed of three lenses, and the three lenses are composed of a cemented lens component in which a positive lens and a negative lens are cemented in order from the object side, and a single lens. It is characterized by satisfying.
      1.0 <R_C3/ R_C1  <10
  However, R_C3Is the radius of curvature on the optical axis of the most image side surface of the cemented lens component in the third lens group, R_C1Is a radius of curvature of the cemented lens component in the third lens group on the optical axis of the most object side surface.
  Moreover, the zoom lens according to the fifteenth aspect of the present invention is in order from the object side.Has positive refractive power,A first lens group that is a fixed most object side lens group at the time of zooming, a second lens group that has a negative refractive power and moves on the optical axis at the time of zooming, and a positive lens A third lens group as a second moving lens group having refractive power and moving on the optical axis at the time of zooming;Has positive refractive power,The most image side lens group arranged closest to the image side,Consist ofThe first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending an optical path, and a positive lens component, and the reflecting surface is variable in shape, The three lens group is composed of three lenses, and the three lenses are composed of a three-element cemented lens component in which a positive lens, a negative lens, and a positive lens are cemented in order from the object side. It is characterized by satisfaction.
      −4.0 <(R_CF+ R_CR) / (R_CF-R_CR<0
  However, R_CFIs the radius of curvature on the optical axis of the surface closest to the object of the three-piece cemented lens component, R_CRIs the radius of curvature on the optical axis of the surface closest to the image side of the three-piece cemented lens component.
  The zoom lens according to the sixteenth invention is characterized in that, in any of the twelfth and fifteenth inventions, the following conditional expression is satisfied.
      0.6 <Dc / fw <1.8
  Here, Dc is the distance on the optical axis from the most object side surface to the most image side surface of the three-piece cemented lens component, and fw is the focal length of the entire system at the wide angle end of the zoom lens.
  In the twelfth, fifteenth, or sixteenth invention, the zoom lens according to the seventeenth invention satisfies the following conditional expression.
    0.002 / mm²  <Σ | (1 / Rci) − (1 / Rca) |²  <0.05mm²
  Where Rci is the radius of curvature on the optical axis of the i-th cemented surface from the object side of the three-piece cemented lens component, and Rca is Rca = m / | Σ (1 / Rci) | (i = 1... M) Here, m is 2 of the number of joint surfaces.
  The zoom lens according to the eighteenth aspect of the invention is characterized in that, in any of the twelfth and fifteenth to seventeenth aspects of the invention, the following conditional expression is satisfied.
      5 × 10^-Five  <Σ | (1 / νcj + 1) − (1 / νcj) |²  <4 × 10^-3
  Where νcj is the Abbe number of the medium with respect to the i-th d-line reference from the object side of the three-piece cemented lens component, j = 1... N−1, where n is three of the number of lenses to be joined. is there.
  The zoom lens according to the nineteenth invention is characterized in that, in any one of the twelfth and fifteenth to eighteenth inventions, the following conditional expression is satisfied.
      0.005 <Σ | ncj + 1−ncj |²  <0.5
  Here, ncj is the refractive index of the medium with respect to the i-th d-line reference from the object side of the three-piece cemented lens component, j = 1... N−1, where n is three of the number of lenses to be joined. is there.
  The zoom lens according to the twentieth invention is characterized in that, in either the first or second invention, the negative lens component of the most object side lens group is an aspherical surface.
  The zoom lens according to the twenty-first aspect of the invention is characterized in that, in the twentieth aspect of the invention, the following conditional expression is satisfied:
      -2.5 <(R_1PF+ R_1PR) / (R_1PF-R_1PR<0.6
  However, R_1PFIs the radius of curvature on the optical axis of the object side surface of the positive lens component of the most object side lens group, R_1PRIs the radius of curvature on the optical axis of the image side surface of the positive lens component of the most object side lens group.
  The zoom lens according to the twenty-second aspect of the invention is characterized in that, in the second aspect of the invention, the second lens group is composed of two lenses of a negative lens and a positive lens in order from the object side. To do.
  The zoom lens according to the twenty-third aspect of the present invention is the zoom lens according to the twenty-second aspect, wherein the second lens group is a cemented lens component composed of a negative lens and a positive lens in order from the object side. It is characterized by being.
  In the zoom lens according to the twenty-fourth aspect of the invention, in order from the object side,Has positive refractive power,A first lens group that is a fixed most object side lens group at the time of zooming, a second lens group that has a negative refractive power and moves on the optical axis at the time of zooming, and a positive lens A third lens group as a second moving lens group having refractive power and moving on the optical axis at the time of zooming;Has positive refractive power,The most image side lens group arranged closest to the image side,Consist ofThe first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending an optical path, and a positive lens component, and the reflecting surface is variable in shape, The two lens group is a cemented lens component composed of two lenses of a negative lens and a positive lens in order from the object side, and satisfies the following conditional expression.
      -1.6 <(R_2F+ R_2R) / (R_2F-R_2R<0.3
  However, R_2FIs the radius of curvature on the optical axis of the most object side surface of the second lens group (junction lens component), R_2RIs the radius of curvature on the optical axis of the surface closest to the image side of the second lens group (junction lens component).
  The zoom lens according to the twenty-fifth aspect of the invention is characterized in that, in any of the first to twenty-fourth aspects, the zoom lens satisfies the following conditional expression.
      1.8 <fT / fw
  Here, fT is the focal length of the entire zoom lens system at the telephoto end, and fw is the focal length of the entire zoom lens system at the wide angle end.
  An electronic image pickup apparatus according to the twenty-sixth aspect of the invention includes any one of the first to fifth zoom lenses and an electronic image pickup element arranged on the image side thereof.
  The electronic imaging device according to the twenty-seventh aspect of the present invention is the following, in the twenty-sixth aspect of the invention, when the horizontal pixel pitch of the electronic imaging element is a and the open F value at the wide angle end of the zoom lens is F. It satisfies the following conditional expression.
      F ≧ a / (1 μm)
  In the electronic imaging device according to the twenty-eighth aspect of the invention, in the twenty-seventh aspect of the invention, the inner diameter of the aperture stop that determines the open F value is fixed, and the convex surface faces the stop immediately before or after the stop. The intersection of the optical axis and the perpendicular line extending from the aperture stop to the optical axis is located within 0.5 mm from the inside of the lens or the vertex of the convex surface. .
  The electronic imaging device according to the twenty-ninth aspect of the invention is characterized in that, in the twenty-eighth aspect, the intersection is located within the lens or within the surface apex.
  The electronic imaging apparatus according to the thirtieth aspect of the present invention is the electronic image pickup apparatus according to any of the twenty-seventh to twenty-ninth aspects of the present invention, further comprising transmittance varying means for adjusting the amount of light guided to the electronic imaging element by changing the transmittance. The transmittance varying means is arranged in an optical path in a space different from the space in which the diaphragm is arranged.
  The electronic image pickup apparatus according to the thirty-first invention is the electronic image pickup device according to any one of the twenty-seventh to thirty-third inventions, further comprising a shutter for adjusting a light receiving time of a light beam guided to the electronic image pickup device. It is characterized in that it is arranged in an optical path in a space different from the space in which is arranged.
  The electronic imaging device according to the thirty-second invention is characterized in that, in any of the twenty-sixth to thirty-first inventions, no low-pass filter is arranged in the optical path from the incident surface of the optical system to the imaging surface.
  In the electronic imaging device according to the thirty-third aspect of the invention, in any of the twenty-sixth to thirty-first aspects of the invention, the medium boundary surfaces arranged between the zoom lens and the imaging surface are all substantially flat. There is no spatial frequency conversion effect like an optical low pass filter.
  An electronic imaging apparatus according to the thirty-fourth aspect of the invention is characterized in that, in the twenty-sixth aspect of the invention, the following conditional expression is satisfied:
      1.4 <d / L <3.0
  Where d is an air-converted length measured along the optical axis from the image side apex of the negative lens component to the object side apex of the positive lens component in the most object side lens group, and L is effective imaging of the electronic image sensor. The diagonal length of the region.
  The electronic imaging apparatus according to the thirty-fifth aspect of the invention is characterized in that, in the thirty-fourth aspect of the invention, the negative lens component of the lens unit on the most object side is composed of a negative single lens and satisfies the following conditional expression: To do.
      26 <ν1N
      −0.1 <√ (fw · fT) / f1 <0.6
  Where ν1N is the Abbe number on the d-line basis of the medium of the negative single lens in the most object side lens group, f1 is the focal length of the most object side lens group, and fw is the entire system at the wide angle end of the zoom lens. Is the focal length of the entire system at the telephoto end of the zoom lens.
  An electronic imaging apparatus according to the thirty-sixth aspect of the invention includes any of the tenth or thirteenth zoom lens and an electronic imaging element disposed on the image side thereof, and satisfies the following conditional expression: And
      -0.7 <L / R_C2  <0.1
      15 <v_CP− Ν_CN
  However, L is the diagonal length (mm) of the image sensor. It is assumed that the image sensor is used so that the wide angle end angle of view includes 55 degrees or more. R_C2Is the radius of curvature on the optical axis of the cemented surface of the cemented lens component in the third lens group, ν_CPIs the Abbe number of the positive lens medium of the cemented lens component in the third lens group, ν_CNIs the Abbe number of the medium of the negative lens in the cemented lens component of the third lens group.
  An electronic image pickup apparatus according to the thirty-seventh aspect of the invention includes any one of the eleventh or fourteenth zoom lens and an electronic image pickup element disposed on the image side thereof, and satisfies the following conditional expression: And
      -1.1 <L / R_C2  <0
      15 <v_CP  − Ν_CN
  However, L is the diagonal length (mm) of the image sensor. It is assumed that the image sensor is used so that the wide angle end angle of view includes 55 degrees or more. R_C2Is the radius of curvature on the optical axis of the cemented surface of the cemented lens component in the third lens group, ν_CPIs the Abbe number of the positive lens medium of the cemented lens component in the third lens group, ν_CNIs the Abbe number of the medium of the negative lens in the cemented lens component of the third lens group.
  The electronic imaging device according to the thirty-eighth aspect of the invention is the electronic imaging device according to any of the twenty-sixth or thirty-seventh to thirty-seventh aspects, wherein the wide angle end full angle of view of the electronic imaging device is 55 degrees or more. .
Furthermore, the electronic imaging device according to the thirty-ninth aspect of the present invention is characterized in that, in the thirty-eighth aspect, the full angle of view at the wide angle end in the electronic imaging device is 80 degrees or less.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Prior to the description of the embodiments, the reason and action of adopting the above configuration in the present invention will be described.
The image pickup apparatus of the present invention employs a configuration in which the optical path (optical axis) of the zoom lens system is bent by a reflective optical element such as a mirror, and incorporates various contrivances toward miniaturization thereof.
[0014]
The basic configuration of the zoom lens system according to the present invention includes a lens group closest to the object side (hereinafter referred to as a first lens group), a negative lens component, and a reflecting surface (surface) for bending the optical path in order from the object side. Mirror) and a positive lens component, which are immovable both at the time of zooming and in focus, and the most image side lens group (hereinafter referred to as the final lens group) is an aspherical surface. And the lens is immovable at the time of focusing, and further has another lens group movable between the two groups for zooming. (In this application, the lens component is a lens in which only the lens surface closest to the object side and the lens surface closest to the image side are in contact with the air gap and do not include the air gap therebetween. Unit.)
However, if the first lens group is provided with a reflecting surface (surface mirror) for bending the optical path, the following two problems arise.
First, the entrance pupil is deepened, and each lens element that originally constitutes the first lens group having a large diameter is further enlarged, and the feasibility of optical path bending itself becomes a problem.
Secondly, the combined magnification of each lens group that originally has a zooming function and controls the zooming function on the image side of the first lens group approaches zero, and the zooming ratio becomes low for the amount of movement.
[0015]
First, the conditions for establishing the optical path bending will be described.
If the first lens group is provided with a reflecting surface (surface mirror) for bending the optical path, the entrance pupil position inevitably tends to be deep, and the diameter and size of each optical element constituting the first lens group are enlarged. The optical path bending is difficult to be physically established.
Accordingly, the first lens group includes, in order from the object side, a negative lens having a convex surface directed toward the object side, a reflecting surface (surface mirror) for bending the optical path, and a positive lens, thereby reducing the entrance pupil. To do.
[0016]
Since the negative lens and the positive lens in the first lens group are arranged at a distance from each other while having a strong power of a certain level or more, in order to secure a space for bending the optical path in this way, Each off-axis aberration, such as aberration, astigmatism, and distortion, is inevitably worsened, but this can be corrected by introducing an aspherical surface into the final lens group.
On the other hand, the amount of off-axis aberration correction due to the aspherical surface of the last lens group is quite large, and when this is used for rear focusing, the off-axis aberration varies significantly. Therefore, the final lens group is fixed at the time of focusing, and it is preferable to use another optical element in the system, for example, by controlling the shape of the reflecting surface (surface mirror) for bending the optical path as variable.
[0017]
In order to physically establish the bending, it is preferable to satisfy the following conditional expressions (1) and (2), and further satisfy (3).
0.9 <−f11 / √ (fw · fT) <2.4 (1)
1.6 <f12 / √ (fw · fT) <3.6 (2)
1.4 <d / L <3.0 (3)
Where f11 is the focal length of the negative lens component in the most object side lens group, f12 is the focal length of the positive lens component in the most object side lens group, fw is the focal length of the entire system at the wide angle end of the zoom lens, and fT is the zoom lens. The focal length of the entire system at the telephoto end, d is the air-converted length measured along the optical axis from the image side apex of the negative lens component to the object side apex of the positive lens component in the most object side lens unit, and L is the electron It is the diagonal length of the effective imaging area of an image sensor.
[0018]
In order to physically enable optical path bending by making the entrance pupil shallow, it is preferable to satisfy the conditional expressions (1) and (2) and increase the power of the lens elements on both sides of the first lens group.
If both conditional expressions (1) and (2) exceed the upper limit, the entrance pupil will remain deep, so the diameter and size of each optical element composing the first lens group will be enlarged if a certain angle of view is to be secured. Therefore, the optical path bending is difficult to be physically established.
On the other hand, if the lower limit of conditional expressions (1) and (2) is not reached, the diameter of the positive lens in the first lens group will be enlarged, making it difficult to correct off-axis aberrations such as coma, astigmatism, and distortion. Become.
[0019]
Conditional expression (3) is a conditional expression that defines the length measured along the optical axis necessary for providing a reflecting surface (surface mirror) for bending the optical path.
The value of conditional expression (3) should be as small as possible. However, if the value is below the lower limit, optical path bending will not be established, or the light beam contributing to image formation at the periphery of the screen will not reach the image plane satisfactorily.
On the other hand, if the upper limit value of conditional expression (3) is exceeded, correction of each off-axis aberration becomes difficult as in conditional expressions (1) and (2).
[0020]
It is more preferable that at least one of the following conditional expressions (1 ′), (2 ′), and (3 ′) is satisfied.
1.1 <−f11 / √ (fw · fT) <2.1 (1 ′)
1.8 <f12 / √ (fw · fT) <3.3 (2 ′)
1.5 <d / L <2.7 (3 ′)
Furthermore, it is best to satisfy at least one of the following conditional expressions (1 "), (2"), and (3 ").
1.3 <−f11 / √ (fw · fT) <1.8 (1 ”)
2.0 <f12 / √ (fw · fT) <3.0 (2 ")
1.6 <d / L <2.5 (3 ")
[0021]
Further, as described above, if the negative lens and the positive lens of the first lens group are arranged at a distance from each other while having a strong power of a certain degree or more, the variation amount of the chromatic aberration of magnification due to zooming tends to increase. is there. Therefore, the following conditional expressions (4) and (5) should be satisfied.
26 <ν1N (4)
−0.1 <√ (fw · fT) / f1 <0.6 (5)
Where ν1N is the Abbe number of the negative lens medium on the object side of the first lens group, f1 is the focal length of the first lens group, fw is the focal length of the entire system at the wide angle end of the zoom lens, and fT is the telephoto end of the zoom lens. Is the focal length of the entire system.
[0022]
If the lower limit of conditional expression (4) is not reached, the variation in magnification chromatic aberration during zooming becomes large, which is not preferable. There is no restriction on the upper limit value of conditional expression (4).
If the upper limit value of conditional expression (5) is exceeded, off-axis aberration correction and chromatic aberration correction become difficult. In particular, lateral chromatic aberration may be difficult to correct even if conditional expression (4) is satisfied.
On the other hand, if the lower limit value of conditional expression (5) is not reached, there may be a case where the aberration fluctuation due to the movement of the lens group that moves for zooming becomes large.
[0023]
It is better to satisfy either of the following conditional expressions (4 ′) and (5 ′).
30 <ν1N (4 ')
−0.05 <√ (fw · fT) / f1 <0.4 (5 ′)
Furthermore, it is best to satisfy one of the following conditional expressions (4 ") and (5").
33 <ν1N (4 ")
0 <√ (fw · fT) / f1 <0.2 (5 ")
[0024]
Next, a zooming and focusing method of a zoom lens having a reflecting surface (surface mirror) for bending the optical path will be described. As the scaling method, the following three methods are conceivable.
(1) In order from the object side, the first lens group that has a negative refractive power and includes a reflecting surface (surface mirror) and does not move, and the object side that has a positive refractive power and changes magnification from the wide-angle end to the telephoto end. A zoom system comprising a second lens group that moves only to the third lens group, a third lens group that moves differently from the second lens group during zooming, and a final lens group that has an aspherical surface and does not move.
(2) In order from the object side, the first lens unit having positive refractive power and including a reflecting surface (surface mirror) and not moving, and the image side at the time of zooming from the wide angle end to the telephoto end with negative refractive power A zoom system comprising a second lens group that moves only to the third lens group, a third lens group that moves only in the direction opposite to the second lens group during zooming, and a final lens group.
(3) In order from the object side, the first lens group having positive refractive power and including a reflecting surface (surface mirror) and not moving, and the image side at the time of zooming from the wide-angle end to the telephoto end with negative refractive power A second lens group that moves back and forth convexly, a third lens group that has positive refractive power and moves only to the object side upon zooming from the wide-angle end to the telephoto end, and a stationary final lens that has an aspheric surface A zoom system consisting of groups.
[0025]
First, the method (1) has a drawback that it is difficult to apply power to the third lens group because of securing a zoom ratio, and the amount of movement becomes too large and the inclination of the cam tends to increase. Therefore, in the present invention, the above method (2) or (3) is adopted.
Next, in the above method (2), the power of the negative lens on the object side of the first lens group is weak, or the power of the positive lens on the image side of the first lens group is too strong. There are difficulties in reducing the depth, correcting off-axis aberrations, correcting lateral chromatic aberration, and the like.
On the other hand, in the method (3), there is no problem in aberration correction, zoom movement, and size, except when it is necessary to secure a space for moving the second lens group for focusing.
Therefore, in the present invention, the above method (3) is adopted. Thereby, the focus can be controlled by controlling the shape of the reflecting surface (surface mirror) for bending the optical path as variable.
[0026]
Furthermore, the following conditional expressions (6) and (7) should be satisfied.
0.3 <−βRw <0.8 (6)
0.8 <fRw / √ (fw · fT) <2.0 (7)
Where βRw is the combined magnification after the third lens group at the wide-angle end when focusing on an object point at infinity, fRw is the combined focal length after the third lens group at the wide-angle end when focusing on an object point at infinity, fw Is the focal length of the entire system at the wide-angle end of the zoom lens, and fT is the focal length of the entire system at the telephoto end of the zoom lens.
[0027]
If the lower limit of conditional expression (6) is not reached, a sufficiently high zoom ratio cannot be obtained in the entire zoom lens system, or the moving space becomes too large and the size becomes enlarged.
On the other hand, exceeding the upper limit of conditional expression (6) is rare in theory, but still requires a lot of moving space.
If the lower limit of conditional expression (7) is not reached, the zooming efficiency will deteriorate due to a decrease in the combination magnification after the third lens group.
On the other hand, if the upper limit value of conditional expression (7) is exceeded, the zooming efficiency deteriorates due to an increase in the combined focal length after the third lens group.
[0028]
It is better to satisfy either of the following conditional expressions (6 ′) and (7 ′).
0.35 <−βRw <0.75 (6 ′)
1.0 <fRw / √ (fw · fT) <1.8 (7 ′)
Furthermore, it is best to satisfy one of the following conditional expressions (6 ") and (7").
0.4 <−βRw <0.7 (6 ")
1.2 <fRw / √ (fw · fT) <1.6 (7 ")
[0029]
Note that focusing in the zoom lens of the present invention may be performed by moving any lens group in the normal zoom lens, but in order to reduce the driving amount of the lens group in the zoom lens barrel and reduce the size. In addition, focusing may be performed by variably controlling the shape of the reflecting surface of the first lens group.
For example, the reflective surface is composed of a thin film coated with metal or dielectric, and the thin film is connected to a power source via a plurality of electrodes and variable resistors, and further provided with an arithmetic unit for controlling a variable resistance value, It is preferable to change the shape of the reflecting surface by controlling the distribution of electrostatic force applied to the thin film.
[0030]
By the way, it is advantageous that the shape-variable reflecting surface is small in terms of manufacturability and controllability.
In addition, the reduction of the camera depth when the downsizing of the image pickup device is advanced is more advantageous in the method of folding the optical path as in the present invention than in the retracted method.
Therefore, in order to make the camera thinner, the horizontal pixel pitch a (μm) of the electronic image pickup element is set to the following conditional expression (5) with respect to the open F value at the wide angle end of the zoom lens.
F ≧ a (5)
It is effective to use the zoom lens of the present invention by using an electronic image pickup element that is small enough to satisfy the relationship. At that time, it is better to devise the following method.
[0031]
As the image sensor becomes smaller, the pixel pitch also becomes smaller in proportion, and image quality deterioration due to the influence of diffraction cannot be ignored. In particular, when the relationship between the open F value at the wide-angle end and the horizontal pixel pitch a (μm) of the electronic image sensor to be used is reduced to satisfy the above conditional expression (5), only open use is possible. .
Therefore, the aperture stop that determines the F value has a fixed inner diameter, and does not insert or remove the aperture stop or replace it. Then, at least one of the refracting surfaces adjacent to the aperture stop has a convex surface facing the aperture stop (in the present invention, the refracting surface adjacent to the image side corresponds), and a perpendicular line extending from the aperture stop to the optical axis. And the optical axis is located within 0.5 mm from the top of the convex surface, or the convex surface intersects or contacts the inner diameter portion of the aperture stop member including the back surface of the aperture stop part. In this way, the space for the aperture stop, which has occupied the space significantly compared to the prior art, is no longer necessary, and the space can be saved greatly, contributing significantly to downsizing.
[0032]
For light quantity adjustment, it is preferable to use transmittance varying means instead of the aperture stop. The transmittance varying means can be placed in any position in the optical path, so it is preferable to place the transmittance varying means in a space that originally has enough space. In particular, in the case of the present invention, it is preferable to insert between the lens group that moves for zooming and the image sensor. As the transmittance varying means, a device whose transmittance is variable by voltage or the like may be used, or a plurality of filters having different transmittances may be combined by being inserted and removed or replaced. In addition, a shutter for adjusting the light receiving time of the light beam guided to the electronic image sensor is preferably arranged in a space different from the aperture stop.
[0033]
Further, in the relationship between the open F value at the wide-angle end and the horizontal pixel pitch a (μm) of the electronic image sensor to be used, if the above conditional expression (5) (F ≧ a) is satisfied, there is no need for an optical low-pass filter. good. That is, all the media on the optical path between the zoom lens system and the image sensor may be air or an amorphous medium. This is because there are almost no frequency components that can cause aliasing distortion due to degradation of imaging characteristics due to diffraction and geometric aberration. Alternatively, each optical element between the zoom lens system and the electronic image pickup element has a medium boundary surface that is almost flat and has no spatial frequency characteristic conversion action such as an optical low-pass filter. It may be configured.
[0034]
Next, a method for satisfactorily securing variable magnification and correcting aberration will be described.
It is the configuration of the third lens group that is deeply involved in both of these. Although it is advantageous to increase the number of components, there is a problem in achieving the maximum purpose of downsizing. For this reason, it is important to configure with as few sheets as possible. Since the third lens group has a zooming function, it moves only to the object side when zooming from the wide-angle end to the telephoto end, but it is necessary to configure the third lens group for aberration correction. The total number of lenses is three, including one positive lens and one negative lens. However, the decentering sensitivity of the negative lens (the amount of increase in aberration with respect to the unit decentering amount) is large. For this reason, it is preferable to join the negative lens with any positive lens in the third lens group.
Therefore, the configuration in the third lens group is
A. In order from the object side, single lens and cemented lens components of positive lens and negative lens
B. In order from the object side, a cemented lens component of a positive lens and a negative lens, and a single lens
C. In order from the object side, three-piece cemented lens component of positive lens, negative lens, and positive lens
There are three ways.
[0035]
In order to keep the movement space of the second lens group and the third lens group that move during zooming small, it is preferable that the magnification of the third lens group be −1 at the intermediate focal length. However, if the first lens group of the present invention is configured as described above, the image point by the system before the third lens group, that is, the object point with respect to the third lens group is inevitably farther from the object side than the normal, so The magnification of the lens group is close to zero, and a large movement space is required.
[0036]
However, when the third lens group is configured as A, the front principal point of the third lens group is located closer to the object side, so that there is an advantage that the disadvantage can be eliminated. Similarly, since the rear principal point is also located closer to the object side, there is no wasted space after the third lens group. Therefore, it is effective for shortening the length after the optical path bending portion.
On the other hand, when the third lens group is configured as A, the exit pupil position tends to be close, and the amount of change in the F value due to zooming is large, making it more susceptible to diffraction at the telephoto end. There is a drawback.
Therefore, when the third lens group is configured as in A above, it is suitable for using a slightly larger image pickup element in addition to being easily reduced in size.
[0037]
On the other hand, when the third lens group is configured as B or C, the opposite is the case, but the length is longer than when the third lens group is configured as A, but the exit pupil position or the F value at the time of zooming. Since it is advantageous in terms of change, a smaller image sensor is suitable.
[0038]
When the third lens group is configured as A, the following conditional expression (8A) is satisfied. When the third lens group is configured as B, the following conditional expression (8B) is satisfied. It is good to satisfy.
0.4 <R_C3/ R_C1  <0.8… (8A)
1.0 <R_C3/ R_C1  <10 ... (8B)
However, R_C3Is the radius of curvature on the optical axis of the surface closest to the image side of the cemented lens component in the third lens group, R_C1Is the radius of curvature on the optical axis of the most object side surface of the cemented lens component in the third lens group.
[0039]
Exceeding the upper limit values of the conditional expressions (8A) and (8B) is advantageous for correcting spherical aberration, coma aberration, and astigmatism of the entire system aberration, but has little effect of reducing the eccentric sensitivity due to the joint.
On the other hand, if the lower limit value of conditional expressions (8A) and (8B) is not reached, correction of spherical aberration, coma aberration, and astigmatism of the total system aberration tends to be difficult.
When the third lens group is configured as A, the following conditional expression (8′A) is satisfied, and when the third lens group is configured as B, the following conditional expression ( It is even better if 8'B) is satisfied.
0.45 <R_C3/ R_C1  <0.7 (8'A)
1.5 <R_C3/ R_C1  <8… (8'B)
Further, when the third lens group is configured as A, the following conditional expression (8 "A) is satisfied, and when the third lens group is configured as B, the following conditional expression ( It is best to satisfy 8 "B).
0.5 <R_C3/ R_C1  <0.6 (8 "A)
2 <R_C3/ R_C1  <6 ... (8 "B)
[0040]
Further, regarding chromatic aberration correction, the following conditional expressions (9A) and (10A) (when the third lens group is configured as A), or conditional expressions (9B) and (10B) (and above, It is preferable that the three lens groups are configured as shown in B above.
-0.7 <L / R_C2  <0.1 (9A)
15 <v_CP  −ν_CN                              … (10A)
-1.1 <L / R_C2  <0 (9B)
15 <v_CP  −ν_CN                              … (10B)
However, L is the diagonal length (mm) of the image sensor to be used. It is assumed that the image sensor is used so that the wide angle end angle of view includes 55 degrees or more. R_C2Is the radius of curvature on the optical axis of the cemented surface of the cemented lens component in the third lens group, ν_CPIs the Abbe number of the medium of the positive lens of the cemented lens component in the third lens group, ν_CNIs the Abbe number of the medium of the negative lens in the cemented lens component of the third lens group.
[0041]
If the lower limit of conditional expressions (9A) and (9B) is not reached, it is advantageous for correction of axial chromatic aberration and lateral chromatic aberration, but chromatic aberration of spherical aberration is likely to occur, and in particular, spherical aberration at the reference wavelength is good. Even if it can be corrected, the short wavelength spherical aberration is overcorrected and causes color blur in the image.
On the other hand, if the upper limit value of (9A) and (9B) is exceeded, the axial chromatic aberration and lateral chromatic aberration are likely to be undercorrected or undercorrected due to short wavelength spherical aberration.
If the lower limit value of conditional expressions (10A) and (10B) is not reached, axial chromatic aberration tends to be undercorrected.
On the other hand, there is no combination of media exceeding the upper limit values of conditional expressions (10A) and (10B) in nature.
[0042]
When the third lens group is configured as A described above, at least one of the following conditional expressions (9′A) and (10′A) is satisfied, or the third lens group is configured as B In such a configuration, it is more preferable that at least one of the following conditional expressions (9′B) and (10′B) is satisfied.
-0.6 <L / R_C2  <0.0 (9'A)
20 <ν_CP  −ν_CN                              … (10'A)
-0.9 <L / R_C2  <-0.2 (9'B)
20 <ν_CP  −ν_CN                              … (10'B)
[0043]
Further, when the third lens group is configured as A described above, at least one of the following conditional expressions (9 "A) and (10" A) is satisfied, or the third lens group is set as B: In such a configuration, it is best to satisfy at least one of the following conditional expressions (9 "B) and (10" B).
-0.5 <L / R_C2  <-0.1 (9 "A)
25 <ν_CP  −ν_CN                              … (10 "A)
-0.7 <L / R_C2  <-0.3 (9 "B)
25 <ν_CP  −ν_CN                              … (10 "B)
For conditional expressions (10A), (10'A), (10 "A), (10B), (10'B), (10" B),_VCP−ν_VCNMay be determined not to exceed 90. A combination of media exceeding the upper limit 90 does not exist in nature.
Furthermore, ν_VCP−ν_VCNIt is desirable not to exceed 60. When the upper limit value 60 is exceeded, the material used becomes expensive.
[0044]
On the other hand, when the third lens group is configured as C, it is preferable to satisfy any one or more of the following conditional expressions (11) to (15).
−4.0 <(R_CF+ R_CR) / (R_CF-R_CR<0 (11)
However, R_CFIs the radius of curvature on the optical axis of the surface closest to the object side of the three-piece cemented lens component, R_CRIs the radius of curvature on the optical axis of the most image-side surface of the three-piece cemented lens component.
0.6 <Dc / fw <1.8 (12)
Here, Dc is the distance on the optical axis from the most object side surface to the most image side surface of the three-piece cemented lens component, and fw is the focal length of the entire system at the wide angle end of the zoom lens.
0.002 / mm²<Σ | (1 / Rci) − (1 / Rca) |²<0.05 / mm²…(13)
However, Rci is the radius of curvature on the optical axis of the i-th cemented surface from the object side of the triplet cemented lens component, and Rca is Rca = m / | Σ (1 / Rci) | (i = 1... M) Here, m is 2 of the number of joint surfaces.
5 × 10^-Five<Σ | (1 / νcj + 1) − (1 / νcj) |²<4x10^-3…(14)
Here, νcj is the Abbe number of the medium on the i-th d-line basis from the object side of the three-piece cemented lens component, j = 1... N−1, where n is three of the number of lenses to be joined. .
0.005 <Σ | ncj + 1−ncj |²<0.5
Here, ncj is the refractive index of the medium with respect to the i-th d-line reference from the object side of the three-piece cemented lens component, j = 1... N−1, where n is three of the number of lenses to be joined. .
[0045]
Conditional expression (11) is a conditional expression that defines the shape factor of a cemented lens component having m (m ≧ 2) cemented surfaces in a lens group that moves upon zooming.
If the lower limit of conditional expression (11) is not reached, it becomes difficult to ensure a zoom ratio or shorten the total length in use (this is related to the volume when retracted).
On the other hand, if the upper limit value of conditional expression (11) is exceeded, it will be difficult to correct spherical aberration and coma aberration even if an aspheric surface is introduced.
[0046]
Conditional expression (12) is the optical axis between the most object-side surface and the most image-side surface of the cemented lens component having m (m ≧ 2) cemented surfaces in the lens group that moves upon zooming. It is a conditional expression that defines the above distance (thickness).
If the upper limit of conditional expression (12) is exceeded, the thickness of the entire system when retracted will not be reduced.
On the other hand, if the lower limit of conditional expression (12) is not reached, the radius of curvature of each joint surface cannot be reduced, and the effect of joining (correction of chromatic aberration, etc.) cannot be exhibited.
[0047]
Conditional expression (13) is a conditional expression for each joint surface to exhibit an aberration correction effect.
Exceeding the upper limit value of conditional expression (13) is advantageous for aberration correction, but tends to exceed the upper limit value of conditional expression (12).
On the other hand, if the lower limit of conditional expression (13) is not reached, it is advantageous to make the lens system thinner, but it is not preferable because the aberration correction effects cancel each other out.
[0048]
Conditional expression (14) is a conditional expression that regulates chromatic aberration correction of a cemented lens component having m (m ≧ 2) cemented surfaces in a lens group that moves upon zooming.
If the lower limit of conditional expression (14) is not reached, chromatic aberration correction is insufficient.
On the other hand, if the upper limit value of conditional expression (14) is exceeded, chromatic aberration correction may become excessive.
[0049]
Conditional expression (15) is a conditional expression that prescribes spherical aberration, coma aberration, and field curvature correction of a cemented lens component having m (m ≧ 2) cemented surfaces in a lens group that moves upon zooming. is there.
If the lower limit of conditional expression (15) is not reached, spherical aberration and coma aberration correction is insufficient, and the Petzval sum tends to be a large negative value.
On the other hand, if the upper limit of conditional expression (15) is exceeded, high-order components of spherical aberration and coma are likely to occur, and the Petzval sum tends to be a large positive value.
Conditional expressions (14) and (15) are conditional expressions that define the case where the positive lens has a lower refractive index and a higher Abbe number than the negative lens.
[0050]
Further, if each of the conditional expressions (11) to (15) is further limited to the following conditional expressions (11 ′) to (15 ′), it is possible to further reduce the thickness and improve the performance.
-3.0 <(R_CF+ R_CR) / (R_CF-R_CR<−0.3… (11 ')
0.8 <Dc / fw <1.6 (12 ')
0.004 / mm²<Σ | (1 / Rci) − (1 / Rca) |²<0.04 / mm²…(13')
1 × 10^-Four<Σ | (1 / νcj + 1) − (1 / νcj) |²<3 × 10^-3…(14')
0.01 <Σ | ncj + 1−ncj |²  <0.4 (15 ')
[0051]
If each of the conditional expressions (11) to (15) is further limited to the following conditional expressions (11 ") to (15"), the thinnest and higher performance can be achieved.
-2.0 <(R_CF+ R_CR) / (R_CF-R_CR) <-0.5 ... (11 ")
1.0 <Dc / fw <1.4 (12 ")
0.006 / mm²<Σ | (1 / Rci) − (1 / Rca) |²<0.03 / mm²…(13")
2 × 10^-Four<Σ | (1 / νcj + 1) − (1 / νcj) |²<2 × 10^-3…(14")
0.02 <Σ | ncj + 1−ncj |²  <0.3 (15 ")
[0052]
Furthermore, in the zoom lens of the present invention, it is preferable to introduce an aspherical surface to the object side negative lens in the first lens group.
Further, it is preferable that the image side positive lens in the first lens group satisfies the following conditional expression (16).
-2.5 <(R_1PF+ R_1PR) / (R_1PF-R_1PR<0.6 ... (16)
However, R_1PFIs the radius of curvature of the positive lens component of the most object side lens group on the optical axis of the object side surface, R_1PRIs the radius of curvature on the optical axis of the image side surface of the positive lens component of the most object side lens group.
[0053]
If the upper limit of conditional expression (16) is exceeded, high-order lateral chromatic aberration tends to occur.
On the other hand, if the lower limit of conditional expression (16) is not reached, the entrance pupil tends to be deep.
It is better to satisfy the following conditional expression (16 ′).
-2 <(R_1PF+ R_1PR) / (R_1PF-R_1PR<0.2 ... (16 ')
Furthermore, it is best to satisfy the following conditional expression (16 ").
-1.5 <(R_1PF+ R_1PR) / (R_1PF-R_1PR<-0.2 ... (16 ")
[0054]
Further, regarding the second lens group, since the focal length is long, the configuration of two lenses of a negative lens and a positive lens in order from the object side is sufficient. Furthermore, joining is preferable because it can reduce the eccentric sensitivity. The cemented lens component preferably satisfies the following conditional expression (17).
-1.6 <(R_2F+ R_2R) / (R_2F-R_2R<0.3 ... (17)
However, R_2FIs the radius of curvature of the second lens group (junction lens component) on the optical axis of the surface closest to the object side, R_2RIs the radius of curvature on the optical axis of the surface closest to the image side of the second lens group (junction lens component).
[0055]
If the upper limit of conditional expression (17) is exceeded, the entrance pupil tends to be deep.
On the other hand, if the lower limit of conditional expression (17) is not reached, various off-axis aberrations are likely to occur.
It is better to satisfy the following conditional expression (17 ′).
-1.2 <(R_2F+ R_2R) / (R_2F-R_2R<0.1 ... (17 ')
Furthermore, it is best to satisfy the following conditional expression (17 ").
-0.8 <(R_2F+ R_2R) / (R_2F-R_2R) <-0.1 ... (17 ")
[0056]
The zoom lens used in the present invention preferably satisfies the following conditional expression (18).
1.8 <fT / fw (18)
Here, fT is the focal length of the entire zoom lens system at the telephoto end, and fw is the focal length of the entire zoom lens system at the wide angle end.
If the lower limit of conditional expression (18) is not reached, the zoom ratio of the entire zoom lens system will be smaller than 1.8.
Furthermore, it is more preferable that fT / fw does not exceed 5.5.
If it exceeds 5.5, the zoom ratio becomes large, and the amount of movement of the lens group that moves during zooming becomes too large, resulting in an increase in size in the direction in which the optical path is bent, making it impossible to achieve a compact imaging device. .
[0057]
The electronic image sensor used in the present invention is premised on that the wide angle end full angle of view is 55 degrees or more. 55 degrees is a wide angle end full angle of view normally required for an electronic imaging apparatus.
Moreover, it is preferable that the wide angle end angle of view in the electronic imaging apparatus is 80 degrees or less.
If the wide-angle end field angle exceeds 80 degrees, distortion is likely to occur, and it is difficult to make the first lens group compact. Therefore, it is difficult to reduce the thickness of the electronic imaging device.
[0058]
Finally, the requirements for thinning the infrared cut filter will be described.
In an electronic imaging device, an infrared absorption filter having a certain thickness is inserted on the object side of the imaging element so that normal infrared light does not enter the imaging surface.
Consider replacing the infrared absorption filter with a thin coating to shorten or thin the optical system. Then, of course, it becomes thinner by that amount, but there is a secondary effect.
If a near-infrared sharp cut coat having a transmittance at a wavelength of 600 nm of 80% or more and a transmittance at a wavelength of 700 nm of 8% or less is introduced closer to the object side than the image sensor behind the zoom lens system, the absorption type However, the transmittance in the near infrared region having a wavelength of 700 nm or more is low, and the transmittance on the red side is relatively high. The magenta tendency on the bluish-purple side, which is a defect of a solid-state imaging device such as a CCD having a complementary color mosaic filter, is alleviated by gain adjustment, and color reproduction similar to that of a solid-state imaging device such as a CCD having a primary color filter can be obtained. Further, not only primary colors and complementary colors but also color reproduction of those having a strong reflectance in the near infrared region, such as plants and human skin.
[0059]
That is, it is desirable to satisfy the following conditional expressions (19) and (20).
τ600 / τ550 ≧ 0.8 (19)
τ700 / τ550 ≦ 0.08 (20)
However, (tau) 600 is the transmittance | permeability in wavelength 600nm, (tau) 550 is the transmittance | permeability in wavelength 550nm, (tau) 700 is the transmittance | permeability in wavelength 700nm.
It is better to satisfy the following conditional expressions (19 ′) and (20 ′).
τ600 / τ550 ≧ 0.85 (19 ')
τ700 / τ550 ≦ 0.05 (20 ′)
Furthermore, it is best to satisfy the following conditional expressions (19 ") and (20").
τ600 / τ550 ≧ 0.9 (19 ")
τ700 / τ550 ≦ 0.03 (20 ")
[0060]
Another drawback of a solid-state imaging device such as a CCD is that the sensitivity to the near-ultraviolet wavelength of 550 nm is considerably higher than that of the human eye. This also highlights the color blur at the edge of the image due to chromatic aberration in the near ultraviolet region. In particular, it is fatal to downsize the optical system. Therefore, the ratio of the transmittance (τ400) at the wavelength 400 nm to the transmittance (τ550) at the wavelength 550 nm is less than 0.08, and the transmittance (τ440) at the wavelength 440 nm to the transmittance (τ550) at the wavelength 550 nm. If an absorber or reflector whose ratio exceeds 0.4 is inserted in the optical path, the wavelength range necessary for color reproduction is not lost (while maintaining good color reproduction) and noise such as color bleeding is significantly reduced. Is done.
[0061]
That is, it is desirable to satisfy the following conditional expressions (21) and (22).
τ400 / τ550 ≦ 0.08 (21)
τ440 / τ550 ≧ 0.4 (22)
It is even better if the following conditional expressions (21 ′) and (22 ′) are satisfied.
τ400 / τ550 ≦ 0.06 (21 ')
τ440 / τ550 ≧ 0.5 (22 ')
Furthermore, it is best to satisfy the following conditional expressions (21 ") and (22").
τ400 / τ550 ≦ 0.04 (21 ")
τ440 / τ550 ≧ 0.6 (22 ")
These filters are preferably installed between the imaging optical system and the image sensor.
[0062]
On the other hand, in the case of a complementary color filter, since the transmitted light energy is high, the sensitivity is substantially higher than that of a CCD with a primary color filter and it is advantageous in terms of resolution. It is.
[0063]
It should be noted that a better electronic imaging apparatus can be configured by appropriately combining the above conditional expressions and configurations.
In each conditional expression, only the upper limit value or only the lower limit value may be limited by the corresponding upper limit value and lower limit value of the more preferable conditional expression. Moreover, it is good also considering the corresponding value of the conditional expression as described in each below-mentioned Example as an upper limit or a lower limit.
[0064]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
First embodiment
FIG. 1 is a sectional view along an optical axis showing an optical configuration according to a first embodiment of a zoom lens used in an electronic image pickup apparatus according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at a wide angle. Yes. FIG. 2 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the first embodiment when focusing on an object point at infinity, where (a) is a wide angle end, (b) is an intermediate, and (c) is The state at the telephoto end is shown. 3 to 5 are diagrams showing spherical aberration, astigmatism, distortion aberration, and chromatic aberration of magnification when the zoom lens according to the first embodiment is focused on an object point at infinity, FIG. 3 is a wide angle end, and FIG. In the middle, FIG. 5 shows a state at the telephoto end.
[0065]
As shown in FIG. 1, the electronic image pickup apparatus of the first embodiment has a zoom lens and a CCD as an electronic image pickup element in order from the object side. In FIG. 1, I is the imaging surface of the CCD. Between the zoom lens and the imaging surface I, a planar flat CCD cover glass CG is provided.
The zoom lens includes, in order from the object side, a first lens group G1, a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, 4 lens group G4.
The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side.₁A reflective optical element R1 having a reflective surface for bending the optical path, and a biconvex positive lens L1₂It consists of and.
The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and a focusing operation is performed by changing the shape of the reflecting surface.
In each embodiment of the present invention, the aspect ratio of the effective imaging area is 3: 4, and the bending direction is the horizontal direction.
The second lens group G2 includes a biconcave negative lens L2 in order from the object side.₁Positive meniscus lens L2 with a convex surface facing the object side₂And has a negative refractive power as a whole.
The third lens group G3 includes a biconvex positive lens L3 in order from the object side.₁And biconcave negative lens L3₂A positive meniscus lens L3 having a convex surface facing the object side_ThreeAnd has a positive refractive power as a whole.
The fourth lens group G4 includes, in order from the object side, a positive meniscus lens L4 having a concave surface directed toward the object side.₁It consists of
[0066]
When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is reciprocally moved along a locus convex toward the image side (that is, After moving to the image side to temporarily widen the distance from the first lens group G1, the distance to the first lens group G1 is reduced while moving to the object side). It moves only to the side.
The positions of the first lens group G1 and the fourth lens group G4 are also fixed during the focusing operation.
The aspherical surface is a negative meniscus lens L1 having a convex surface facing the object side in the first lens group G1.₁Positive-side meniscus lens L3 having a convex surface facing the object side in the third lens group G3_ThreePositive meniscus lens L4 with the concave surface facing the object side constituting the fourth lens group G4₁On the image side surface.
[0067]
Next, numerical data of optical members constituting the zoom lens of the first embodiment are shown.
In the numerical data of the first embodiment, r₁, R₂, ... are the radius of curvature of each lens surface, d₁, D₂, ... are the thickness or air spacing of each lens, n_d1, N_d2, ... is the refractive index of each lens at the d-line, ν_d1, Ν_d2,... Are the Abbe number of each lens, Fno. Is the F number, f is the total focal length, and D0 is the distance from the object to the first surface.
In the aspherical shape, the optical axis direction is z, the direction perpendicular to the optical axis is y, the conic coefficient is K, and the aspheric coefficient is A._Four, A₆, A₈, A_TenIs expressed by the following equation.
z = (y²/ R) / [1+ {1- (1 + K) (y / r)²}^1/2] + A_Foury^Four+ A₆y⁶+ A₈y⁸+ A_Teny^Ten
These symbols are common to numerical data in the embodiments described later.
The third and fourth surfaces in the numerical data are virtual surfaces. As a reflective optical element having a reflective surface for bending the optical path, a prism having a refractive index of 1 is assumed, and its entrance surface and exit surface are designed.
[0068]

[0069]

[0070]

[0071]
Second embodiment
FIG. 6 is a cross-sectional view along the optical axis showing an optical configuration according to the second embodiment of the zoom lens used in the electronic image pickup apparatus according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at the wide angle. Yes. FIG. 7 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the second embodiment when focusing on an object point at infinity, where (a) is a wide angle end, (b) is an intermediate, and (c) is The state at the telephoto end is shown.
[0072]
As shown in FIG. 6, the electronic image pickup apparatus of the second embodiment has a zoom lens and a CCD as an electronic image pickup element in order from the object side. In FIG. 6, I is the imaging surface of the CCD. Between the zoom lens and the imaging surface I, a planar flat CCD cover glass CG is provided.
The zoom lens includes, in order from the object side, a first lens group G1, a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, 4 lens group G4.
The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side.₁A reflective optical element R1 having a reflective surface for bending the optical path, and a biconvex positive lens L1₂It consists of and.
The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and a focusing operation is performed by changing the shape of the reflecting surface.
In each embodiment of the present invention, the aspect ratio of the effective imaging area is 3: 4, and the bending direction is the horizontal direction.
The second lens group G2 includes a biconcave negative lens L2 in order from the object side.₁Positive meniscus lens L2 with a convex surface facing the object side₂And has a negative refractive power as a whole.
The third lens group G3 includes a biconvex positive lens L3 in order from the object side.₁And biconcave negative lens L3₂A positive meniscus lens L3 having a convex surface facing the object side_ThreeAnd has a positive refractive power as a whole.
The fourth lens group G4 includes a biconcave negative lens L4 in order from the object side.₁'And biconvex positive lens L4₂And a cemented lens.
[0073]
When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is reciprocally moved along a locus convex toward the image side (that is, After moving to the image side to temporarily widen the distance from the first lens group G1, the distance to the first lens group G1 is reduced while moving to the object side). It moves only to the side.
The positions of the first lens group G1 and the fourth lens group G4 are also fixed during the focusing operation.
The aspherical surface is a negative meniscus lens L1 having a convex surface facing the object side in the first lens group G1.₁Positive-side meniscus lens L3 having a convex surface facing the object side in the third lens group G3_ThreeAnd a biconvex positive lens L4 in the fourth lens group G4.₂On the image side surface.
[0074]
Next, numerical data of optical members constituting the zoom lens of the second embodiment are shown.

[0075]

[0076]

[0077]
Third embodiment
FIG. 8 is a cross-sectional view along the optical axis showing an optical configuration according to the third embodiment of the zoom lens used in the electronic image pickup apparatus according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at the wide angle. Yes. FIG. 9 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the third embodiment when focusing on an object point at infinity, where (a) is a wide angle end, (b) is an intermediate, and (c) is The state at the telephoto end is shown. 10 to 12 are diagrams showing spherical aberration, astigmatism, distortion aberration, and chromatic aberration of magnification when the zoom lens according to the third example is focused on an object point at infinity, FIG. 10 is a wide-angle end, and FIG. In the middle, FIG. 12 shows a state at the telephoto end.
[0078]
As shown in FIG. 8, the electronic image pickup apparatus of the third embodiment has a zoom lens and a CCD as an electronic image pickup element in order from the object side. In FIG. 8, I is the imaging surface of the CCD. Between the zoom lens and the imaging surface I, a planar flat CCD cover glass CG is provided.
The zoom lens includes, in order from the object side, a first lens group G1, a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, 4 lens group G4.
The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side.₁A reflective optical element R1 having a reflective surface for bending the optical path, and a biconvex positive lens L1₂It consists of and.
The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and a focusing operation is performed by changing the shape of the reflecting surface.
In each embodiment of the present invention, the aspect ratio of the effective imaging area is 3: 4, and the bending direction is the horizontal direction.
The second lens group G2 includes a biconcave negative lens L2 in order from the object side.₁Positive meniscus lens L2 with a convex surface facing the object side₂And has a negative refractive power as a whole.
The third lens group G3 includes a biconvex positive lens L3 in order from the object side.₁And biconcave negative lens L3₂Positive meniscus lens L3 with a convex surface facing the object side_ThreeAnd has a positive refractive power as a whole.
The fourth lens group G4 includes, in order from the object side, a negative meniscus lens L4 having a convex surface directed toward the object side.₁"And biconvex positive lens L4₂And a cemented lens.
[0079]
When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is reciprocally moved along a locus convex toward the image side (that is, After moving to the image side to temporarily widen the distance from the first lens group G1, the distance to the first lens group G1 is reduced while moving to the object side). It moves only to the side.
The positions of the first lens group G1 and the fourth lens group G4 are also fixed during the focusing operation.
The aspherical surface is a negative meniscus lens L1 having a convex surface facing the object side in the first lens group G1.₁Image-side surface of the lens, a biconvex positive lens L3 in the third lens group G3₁Positive meniscus lens L3 having a convex surface facing the object side_ThreeSurface on the image side, a biconvex positive lens L4 in the fourth lens group G4₂On the image side surface.
[0080]
Next, numerical data of optical members constituting the zoom lens of the third example are shown.

[0081]

[0082]

[0083]
Fourth embodiment
FIG. 13 is a cross-sectional view along the optical axis showing an optical configuration according to a fourth embodiment of the zoom lens used in the electronic imaging device according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at the wide angle. Yes. FIG. 14 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the fourth example when focusing on an object point at infinity, where (a) is a wide angle end, (b) is an intermediate, The state at the telephoto end is shown. 15 to 17 are diagrams showing spherical aberration, astigmatism, distortion aberration, and chromatic aberration of magnification when the zoom lens according to Example 4 is focused on an object point at infinity, FIG. 15 is a wide angle end, and FIG. In the middle, FIG. 17 shows a state at the telephoto end.
[0084]
As shown in FIG. 13, the electronic image pickup apparatus of the fourth embodiment has a zoom lens and a CCD as an electronic image pickup element in order from the object side. In FIG. 13, I is the imaging surface of the CCD. Between the zoom lens and the imaging surface I, a planar flat CCD cover glass CG is provided.
The zoom lens includes, in order from the object side, a first lens group G1, a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, 4 lens group G4.
The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side.₁A reflective optical element R1 having a reflective surface for bending the optical path, and a biconvex positive lens L1₂It consists of and.
The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and a focusing operation is performed by changing the shape of the reflecting surface.
In each embodiment of the present invention, the aspect ratio of the effective imaging area is 3: 4, and the bending direction is the horizontal direction.
The second lens group G2 includes a biconcave negative lens L2 in order from the object side.₁Positive meniscus lens L2 with a convex surface facing the object side₂And has a negative refractive power as a whole.
The third lens group G3 includes a biconvex positive lens L3 in order from the object side.₁And a biconvex positive lens L3₂'And biconcave negative lens L3_ThreeIt has a positive refractive power as a whole.
The fourth lens group G4 includes a positive meniscus lens L4 having a convex surface directed toward the object side.₁"".
[0085]
When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is reciprocally moved along a locus convex toward the image side (that is, After moving to the image side to temporarily widen the distance from the first lens group G1, the distance to the first lens group G1 is reduced while moving to the object side). It moves only to the side.
The positions of the first lens group G1 and the fourth lens group G4 are also fixed during the focusing operation.
The aspherical surface is a negative meniscus lens L1 having a convex surface facing the object side in the first lens group G1.₁Image-side surface of the lens, a biconvex positive lens L3 in the third lens group G3₁Positive meniscus lens L4 having a convex surface directed toward the object side constituting the fourth lens group G4₁"'Is provided on the object side surface.
[0086]
Next, numerical data of optical members constituting the zoom lens of the fourth example are shown.

[0087]

[0088]

[0089]
Example 5
FIG. 18 is a cross-sectional view along the optical axis showing an optical configuration according to the fifth embodiment of the zoom lens used in the electronic imaging device according to the present invention, and shows a state at the time of folding at the time of focusing on an object point at infinity at the wide angle. Yes. FIG. 19 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the fifth example when focusing on an object point at infinity. (A) is a wide angle end, (b) is an intermediate, and (c) The state at the telephoto end is shown.
[0090]
As shown in FIG. 18, the electronic image pickup apparatus of the fifth embodiment has a zoom lens and a CCD as an electronic image pickup element in order from the object side. In FIG. 18, I is the imaging surface of the CCD. Between the zoom lens and the imaging surface I, a planar flat CCD cover glass CG is provided.
The zoom lens includes, in order from the object side, a first lens group G1, a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, 4 lens group G4.
The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side.₁A reflective optical element R1 having a reflective surface for bending the optical path, and a biconvex positive lens L1₂It consists of and.
The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and a focusing operation is performed by changing the shape of the reflecting surface.
In each embodiment of the present invention, the aspect ratio of the effective imaging area is 3: 4, and the bending direction is the horizontal direction.
The second lens group G2 includes a biconcave negative lens L2 in order from the object side.₁Positive meniscus lens L2 with a convex surface facing the object side₂And has a negative refractive power as a whole.
The third lens group G3 includes a biconvex positive lens L3 in order from the object side.₁And a biconvex positive lens L3₂'And biconcave negative lens L3_ThreeIt has a positive refractive power as a whole.
The fourth lens group G4 includes a positive meniscus lens L4 having a concave surface directed toward the object side.₁It consists of
[0091]
When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is reciprocally moved along a locus convex toward the image side (that is, After moving to the image side to temporarily widen the distance from the first lens group G1, the distance to the first lens group G1 is reduced while moving to the object side). It moves only to the side.
The positions of the first lens group G1 and the fourth lens group G4 are also fixed during the focusing operation.
The aspherical surface is a negative meniscus lens L1 having a convex surface facing the object side in the first lens group G1.₁Image-side surface of the lens, a biconvex positive lens L3 in the third lens group G3₁Positive meniscus lens L4 having a concave surface facing the object side of the fourth lens group G4₁On the image side surface.
[0092]
Next, numerical data of optical members constituting the zoom lens of the fifth example are shown.

[0093]

[0094]

[0095]
Sixth embodiment
FIG. 20 is a sectional view along an optical axis showing an optical configuration according to a sixth embodiment of the zoom lens used in the electronic imaging device according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at the wide angle. Yes. FIG. 21 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the sixth example when focusing on an object point at infinity. (A) is a wide angle end, (b) is an intermediate, and (c) The state at the telephoto end is shown.
[0096]
As shown in FIG. 20, the electronic image pickup apparatus of the sixth embodiment has a zoom lens and a CCD as an electronic image pickup element in order from the object side. In FIG. 20, I is the imaging surface of the CCD. Between the zoom lens and the imaging surface I, a planar flat CCD cover glass CG is provided.
The zoom lens includes, in order from the object side, a first lens group G1, a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, 4 lens group G4.
The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side.₁A reflective optical element R1 having a reflective surface for bending the optical path, and a biconvex positive lens L1₂It consists of and.
The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and a focusing operation is performed by changing the shape of the reflecting surface.
In each embodiment of the present invention, the aspect ratio of the effective imaging area is 3: 4, and the bending direction is the horizontal direction.
The second lens group G2 includes a biconcave negative lens L2 in order from the object side.₁Positive meniscus lens L2 with a convex surface facing the object side₂And has a negative refractive power as a whole.
The third lens group G3 includes a biconvex positive lens L3 in order from the object side.₁And a biconvex positive lens L3₂'And biconcave negative lens L3_ThreeIt has a positive refractive power as a whole.
The fourth lens group G4 includes a biconvex positive lens L4.₁It consists of “”.
[0097]
When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is reciprocally moved along a locus convex toward the image side (that is, After moving to the image side to temporarily widen the distance from the first lens group G1, the distance to the first lens group G1 is reduced while moving to the object side). It moves only to the side.
The positions of the first lens group G1 and the fourth lens group G4 are also fixed during the focusing operation.
The aspherical surface is a negative meniscus lens L1 having a convex surface facing the object side in the first lens group G1.₁Surface on the object side, a biconvex positive lens L3 in the third lens group G3₁Biconvex positive lens L4 constituting the fourth lens group G4₁“” Is provided on the image side surface.
[0098]
Next, numerical data of optical members constituting the zoom lens of the sixth example are shown.

[0099]

[0100]

[0101]
Example 7
FIG. 22 is a sectional view along an optical axis showing an optical configuration according to a seventh embodiment of the zoom lens used in the electronic imaging device according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at the wide angle. Yes. FIG. 23 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the seventh example when focusing on an object point at infinity, where (a) is the wide-angle end, (b) is the middle, and (c) is The state at the telephoto end is shown.
[0102]
As shown in FIG. 22, the electronic image pickup apparatus of the seventh embodiment has a zoom lens and a CCD as an electronic image pickup element in order from the object side. In FIG. 22, I is the imaging surface of the CCD. Between the zoom lens and the imaging surface I, a planar flat CCD cover glass CG is provided.
The zoom lens includes, in order from the object side, a first lens group G1, a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, 4 lens group G4.
The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side.₁A reflective optical element R1 having a reflecting surface for bending the optical path, and a positive meniscus lens L1 having a convex surface facing the object side₂′.
The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and a focusing operation is performed by changing the shape of the reflecting surface.
In each embodiment of the present invention, the aspect ratio of the effective imaging area is 3: 4, and the bending direction is the horizontal direction.
The second lens group G2 includes a biconcave negative lens L2 in order from the object side.₁Positive meniscus lens L2 with a convex surface facing the object side₂And has a negative refractive power as a whole.
The third lens group G3 includes a biconvex positive lens L3 in order from the object side.₁And a biconvex positive lens L3₂'And biconcave negative lens L3_ThreeIt has a positive refractive power as a whole.
The fourth lens group G4 includes a positive meniscus lens L4 having a concave surface directed toward the object surface side.₁It consists of
[0103]
When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is reciprocally moved along a locus convex toward the image side (that is, After moving to the image side to temporarily widen the distance from the first lens group G1, the distance to the first lens group G1 is reduced while moving to the object side). It moves only to the side.
The positions of the first lens group G1 and the fourth lens group G4 are also fixed during the focusing operation.
The aspherical surface is a negative meniscus lens L1 having a convex surface facing the object side in the first lens group G1.₁Image-side surface of the lens, a biconcave negative lens L3 in the third lens group G3_Three'And a positive meniscus lens L4 with a concave surface facing the object surface constituting the fourth lens group G4₁On the image side surface.
[0104]
Next, numerical data of optical members constituting the zoom lens of the seventh example are shown.

[0105]

[0106]

[0107]
Next, values of parameters of the conditional expression in the above embodiment are shown in the following table.

[0108]

[0109]
In each of the embodiments of the present invention, the bending direction is the long side direction (horizontal direction) of the electronic imaging device (CCD) as described above. Bending in the vertical direction requires less space for folding and is advantageous for miniaturization. Can be bent, and the degree of freedom in designing a camera incorporating a lens is increased.
In each of the above embodiments, a low-pass filter is not incorporated, but a low-pass filter may be inserted. Further, as the horizontal pixel pitch a of the electronic image sensor, a value from 1.8 to 3.5 may be used in addition to the above table.
In the table, the bending point is indicated by the distance from the front surface (third surface) of the imaginary surface of the lens modulator (the distance on the 45-degree reflecting surface and the optical axis).
In each of the above embodiments, the reflecting surface of each numerical data is a flat surface when focusing on an infinite object point, and a concave surface when focusing on an object point at close distance.
It should be noted that, from the principle of variable shape, it is preferable that the surface is slightly concave even when focusing on an object point at infinity, and a concave surface with a stronger curvature is used when focusing on an object point at close distance. The radius of curvature of the reflecting surface is at the intersection with the optical axis and may be an aspherical surface.
[0110]
Here, the diagonal length L and the pixel interval a of the effective imaging surface of the electronic imaging device will be described. FIG. 24 is a diagram showing an example of a pixel arrangement of the electronic image pickup element used in each embodiment of the present invention, and R (red), G (green), B (blue) pixels or cyan, magenta, Pixels of four colors of yellow and green (green) (FIG. 27) are arranged in a mosaic pattern. The effective image pickup surface means a region in the photoelectric conversion surface on the image pickup element used for reproduction (display on a personal computer, printing by a printer, etc.) of a taken image. The effective image pickup surface shown in the figure is set to a region narrower than the entire photoelectric conversion surface of the image pickup device in accordance with the performance of the optical system (image circle that can ensure the performance of the optical system). The diagonal length L of the effective imaging surface is the diagonal length of this effective imaging surface. Note that the imaging range used for video reproduction may be variously changed. However, when the zoom lens of the present invention is used in an imaging apparatus having such a function, the diagonal length L of the effective imaging surface changes. In such a case, the diagonal length L of the effective imaging surface in the present invention is the maximum value in the possible range.
[0111]
In each of the above embodiments, a near-infrared cut filter is provided on the image side of the final lens group, or a near-infrared cut coat is provided on the incident surface side surface of the CCD cover glass CG, or on the incident surface side of another lens. It is given on the surface. Further, no low-pass filter is disposed in the optical path from the entrance surface of the zoom lens to the imaging surface. The near-infrared cut filter and near-infrared cut coat surface are configured such that the transmittance at a wavelength of 60 nm is 80% or more and the transmittance at a wavelength of 700 nm is 10% or less. Specifically, it is a multilayer film composed of the following 27 layers, for example. However, the design wavelength is 780 nm.
[0112]

[0113]
The transmittance characteristics of the near infrared sharp cut coat are as shown in FIG.
Further, on the exit surface side of the CCD cover glass CG subjected to the near-infrared cut coat or the exit surface side of another lens subjected to the near-infrared cut coat, a color in a short wavelength region as shown in FIG. The color reproducibility of the electronic image is further enhanced by providing a color filter that reduces the transmission of light or by performing coating.
Specifically, the ratio of the transmittance of the wavelength of 420 nm to the transmittance of the wavelength having the highest transmittance at a wavelength of 400 nm to 700 nm is 15% or more by the near infrared cut filter or the near infrared cut coating. The ratio of the transmittance at a wavelength of 400 nm to the transmittance at the highest wavelength is preferably 6% or less.
Thereby, it is possible to reduce the difference between the recognition of the color of the human eye and the color of the image to be captured and reproduced. In other words, it is possible to prevent deterioration of the image due to the human eye easily recognizing a short wavelength color that is difficult to be recognized by human vision.
[0114]
If the ratio of the transmittance at the wavelength of 400 nm exceeds 6%, the single wavelength castle that is difficult to be recognized by the human eye is regenerated to a wavelength that can be recognized. If the ratio is less than 15%, the reproduction of wavelength castles that can be recognized by humans becomes low, and the color balance becomes poor.
Such means for limiting the wavelength is more effective in an imaging system using a complementary color mosaic filter.
[0115]
In each of the above embodiments, as shown in FIG. 26, the coating has a transmittance of 0% at a wavelength of 400 nm, a transmittance of 90% at a wavelength of 420 nm, and a transmittance peak of 100% at a wavelength of 440 nm.
Then, by multiplying the action with the above-mentioned near-infrared sharp cut coat, the transmittance at a wavelength of 450 nm is peaked at 99%, the transmittance at a wavelength of 400 nm is 0%, the transmittance at a wavelength of 420 nm is 80%, and the wavelength is 600 nm. The transmittance is 82%, and the transmittance at a wavelength of 700 nm is 2%. As a result, more faithful color reproduction is performed.
[0116]
In addition, on the imaging surface I of the CCD, as shown in FIG. 27, a complementary color mosaic filter is provided in which four color filters of cyan, magenta, yellow, and green are provided in a mosaic pattern corresponding to the imaging pixels. ing. These four types of color filters are arranged in a mosaic so that each of them has approximately the same number and adjacent pixels do not correspond to the same type of color filter. Thereby, more faithful color reproduction becomes possible.
[0117]
Specifically, as shown in FIG. 27, the complementary color mosaic filter is composed of at least four types of color filters, and the characteristics of the four types of color filters are preferably as follows.
Green color filter G has wavelength G_PThe yellow color filter Y with a spectral intensity peak at_eIs the wavelength Y_PThe cyan color filter C has a wavelength C_PAnd the magenta color filter M has a wavelength M_P1And M_P2And the following conditional expression is satisfied.
510 nm <G_P  <540 nm
5 nm <Y_P-G_P  <35nm
−100 nm <C_P-G_P  <-5nm
430 nm <M_P1  <480nm
580 nm <M_P2  <640nm
[0118]
Further, the green, yellow, and cyan color filters have an intensity of 80% or more at a wavelength of 530 nm with respect to each spectral intensity peak, and the magenta color filter has an intensity of 10% at a wavelength of 530 nm. From the viewpoint of improving the color reproducibility, it is more preferable that the strength is 50% to 50%.
[0119]
An example of each wavelength characteristic in each of the above embodiments is shown in FIG. The green color filter G has a spectral intensity beak at a wavelength of 525 nm. Yellow color filter Y_eHas a spectral intensity peak at a wavelength of 555 nm. The cyan color filter C has a spectral intensity peak at a wavelength of 510 nm. The magenta color filter M has peaks at a wavelength of 445 nm and a wavelength of 620 nm. In addition, each color filter at a wavelength of 530 nm has a G of 99%, Y_eIs 95%, C is 97%, and M is 38%.
[0120]
In the case of such a complementary color filter, the following signal processing is performed electrically by a controller (not shown) (or a controller used in a digital camera), that is,
Luminance signal
Y = | G + M + Y_e+ C | × 1/4
Color signal
R−Y = | (M + Y_e)-(G + C) |
B−Y = | (M + C) − (G + Y_e) ｜
Through this signal processing, it is converted into R (red), G (green), and B (blue) signals.
The arrangement position of the near infrared sharp cut coat described above may be any position on the optical path.
[0121]
Further, in the numerical data of each of the above embodiments, the distance (d from the position of the aperture stop S to the convex surface of the next image side lens (d₈) Is 0, it means that the surface top position of the convex surface of the lens is equal to the intersection of the optical axis with the perpendicular drawn from the aperture stop S to the optical axis.
In each of the above embodiments, the diaphragm S is a flat plate, but a black coating member having a circular opening may be used as another configuration. Alternatively, a funnel-shaped stop as shown in FIG. 29 may be placed along the inclination of the convex surface of the lens. Furthermore, a stop may be formed in a lens frame that holds the lens.
[0122]
In each of the above embodiments, the transmittance varying means for adjusting the amount of light and the shutter for adjusting the light receiving time in the present invention can be arranged in the air space on the image side of the third lens group G3. Designed to be
As for the light amount adjusting means, as shown in FIG. 30, a turret-like structure in which a transparent surface or a hollow opening, an ND filter with a transmittance of 1/2, an ND filter with a transmittance of 1/4 is provided in a turret shape. Can be used.
[0123]
A specific example is shown in FIG. However, in this figure, the first lens group G1 to the second lens group G2 are omitted for convenience. The turret 10 shown in FIG. 30 enables brightness adjustment of 0, −1, −2, and −3 at a position on the optical axis between the third lens group G3 and the fourth lens group G4. Is arranged. The turret 10 includes an aperture having a transmittance of 100%, an ND filter having a transmittance of 50%, an ND filter having a transmittance of 25%, and a transmittance of 12.5 in the region where the effective light beam is transmitted. % ND filter provided with openings 1A, 1B, 1C, 1D.
The amount of light is adjusted by arranging one of the openings on the optical axis between the lenses, which is a space different from the aperture position, by rotating the turret 10 around the rotation axis 11.
[0124]
Further, as shown in FIG. 32, as the light amount adjusting means, a filter surface capable of adjusting the light amount may be provided so as to suppress unevenness in the light amount. The filter surface of FIG. 32 has concentrically different transmittances, and the amount of light decreases toward the center.
Then, by arranging the filter surface, it may be configured to make the transmittance uniform for a dark subject, giving priority to securing the light amount at the center, and to compensate for uneven brightness only for a bright subject. .
[0125]
Furthermore, in consideration of thinning of the entire apparatus, an electro-optic element that can electrically control the transmittance can be used.
For example, as shown in FIG. 33, the electro-optic element sandwiches a TN liquid crystal cell from two sides with two parallel flat plates each having a polarizing film whose polarization direction matches that of the transparent electrode, and appropriately changes the voltage between the transparent electrodes. Thus, it can be constituted by a liquid crystal filter or the like for adjusting the amount of transmitted light by changing the polarization direction in the liquid crystal.
In this liquid crystal filter, the voltage applied to the TN liquid crystal cell is adjusted via a variable resistor to change the alignment of the TN liquid crystal cell.
[0126]
Furthermore, a shutter for adjusting the light reception time may be provided as the light amount adjusting means in place of the various filters for adjusting the transmittance as described above. Alternatively, a shutter may be provided along with a filter.
The shutter may be composed of a focal plane shutter with a moving curtain arranged in the vicinity of the image plane, or may be composed of various things such as a two-blade lens shutter, a focal plane shutter, and a liquid crystal shutter provided in the middle of the optical path. I do not care.
[0127]
FIG. 34 is a schematic configuration diagram showing an example of a rotary focal plane shutter which is one of focal plane shutters for adjusting a light receiving time applicable to the electronic imaging apparatus according to each embodiment of the present invention, and (a) is a back surface diagram. FIGS. 35 (b) are front views, and FIGS. 35 (a) to 35 (d) are views of the rotary shutter curtain B rotating from the image plane side.
In FIG. 34, A is a shutter substrate, B is a rotary shutter curtain, C is a rotary shaft of the rotary shutter curtain, and D1 and D2 are gears.
[0128]
In the electronic imaging device of the present invention, the shutter substrate A is configured to be disposed immediately before the image plane or in an arbitrary optical path. The shutter substrate A is provided with an opening A1 that transmits the effective light beam of the optical system. The rotary shutter curtain B is formed in a substantially semicircular shape. The rotary shaft C of the rotary shutter curtain is integrated with the rotary shutter curtain B. In addition, the rotation axis C rotates with respect to the shutter substrate A. Further, the rotation axis C is connected to gears D1 and D2 on the surface of the shutter substrate A. The gears D1 and D2 are connected to a motor (not shown).
Then, by driving a motor (not shown), the rotary shutter curtain B is rotated about the rotation axis C through the gears D2, D1 and the rotation axis C in the order of FIGS. 35 (a) to 35 (d). It has become. The rotary shutter curtain B functions as a shutter by shielding and retracting the opening A1 of the shutter substrate A by rotation.
The shutter speed is adjusted by changing the rotation speed of the rotary shutter curtain B.
[0129]
The light amount adjusting means has been described above. However, in the above-described embodiment of the present invention, these shutters and transmittance variable filters are arranged on, for example, the 16th surface of the first embodiment. In addition, as long as these light quantity adjustment means are positions different from the above-mentioned aperture stop, they may be arranged at other positions.
[0130]
Further, the above-described electro-optical element may also serve as a shutter. This is more preferable in terms of reducing the number of parts and reducing the size of the optical system.
[0131]
Next, a configuration example of a variable mirror applicable as a reflective optical element having a reflection surface for bending an optical path in the zoom lens of the present invention will be described.
FIG. 36 is a schematic diagram showing an embodiment of a deformable mirror 409 applicable as a reflecting optical element having a reflecting surface for bending the zoom lens of the present invention.
First, the basic configuration of the optical property variable shape mirror 409 will be described.
[0132]
The deformable mirror 409 is an optical property deformable mirror (hereinafter simply referred to as a deformable mirror) having a thin film (reflecting surface) 409a made of aluminum coating or the like and a plurality of electrodes 409b. A plurality of variable resistors connected to each electrode 409b, 414 is a computing device for controlling the resistance values of the plurality of variable resistors 411, 415, 416 and 417 are temperature sensors connected to the computing device 414, respectively. A humidity sensor and a distance sensor, which are arranged as shown in the figure, constitute one optical device.
[0133]
The surface of the deformable mirror does not have to be a plane, but a spherical surface, a rotationally symmetric aspherical surface, a spherical surface that is decentered with respect to the optical axis, a plane, a rotationally symmetric aspherical surface, or an aspherical surface that has a symmetric surface, or a symmetric surface. May have any shape, such as an aspherical surface having only one surface, an aspherical surface having no symmetry surface, a free-form surface, a surface having a non-differentiable point or line, and any reflection or refracting surface. Any surface that can be affected. Hereinafter, these surfaces are collectively referred to as an extended curved surface.
[0134]
The shape of the reflecting surface of the deformable mirror is preferably a free-form surface. This is because aberration correction is easy and advantageous.
The free-form surface used in the present invention is defined by the following formula. The Z axis of this defining formula is the axis of the free-form surface.
[0135]

Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term. M is a natural number of 2 or more.
In the spherical term,
c: vertex curvature
k: Conic constant (conical constant)
r = √ (X² + Y²)
It is.
[0136]
The free-form surface term is

However, Cj (j is an integer of 2 or more) is a coefficient.
In general, the free-form surface does not have a symmetric surface in both the XZ plane and the YZ plane, but by setting all odd-order terms of X to 0, the plane of symmetry is parallel to the YZ plane. Is a free-form surface with only one. Further, by setting all odd-numbered terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane is obtained.
[0137]
In the deformable mirror of this embodiment, as shown in FIG. 36, a piezoelectric element 409c is interposed between a thin film 409a and an electrode 409b, and these are provided on a support base 423. By changing the voltage applied to the piezoelectric element 409c for each electrode 409b, the piezoelectric element 409c can be partially expanded and contracted to change the shape of the thin film 409a. The shape of the electrode 409b may be concentric division as shown in FIG. 37, rectangular division as shown in FIG. 38, or any other appropriate shape can be selected. . In FIG. 36, reference numeral 424 denotes a shake (blur) sensor connected to the arithmetic unit 414. The arithmetic unit 424 detects, for example, a shake of a digital camera and deforms the thin film 409a so as to compensate for image disturbance due to the shake. The voltage applied to the electrode 409b via 414 and the variable resistor 411 is changed. At this time, signals from the temperature sensor 415, the humidity sensor 416, and the distance sensor 417 are considered at the same time, and focusing, temperature / humidity compensation, and the like are performed. In this case, since stress accompanying deformation of the piezoelectric element 409c is applied to the thin film 409a, it is preferable that the thin film 409a is made thick to some extent and has a corresponding strength.
[0138]
FIG. 39 is a schematic configuration diagram showing still another embodiment of the deformable mirror 409 applicable as a reflecting optical element having a reflecting surface for bending the zoom lens of the present invention.
The deformable mirror of this embodiment is composed of two piezoelectric elements 409c and 409c ′ in which a piezoelectric element interposed between a thin film 409a and an electrode 409b is made of a material having piezoelectric characteristics in opposite directions. In this respect, it differs from the deformable mirror of the embodiment shown in FIG. That is, if the piezoelectric elements 409c and 409c 'are made of a ferroelectric crystal, they are arranged so that the directions of the crystal axes are opposite to each other. In this case, since the piezoelectric elements 409c and 409c ′ expand and contract in the opposite direction when a voltage is applied, the force for deforming the thin film 409a is stronger than in the embodiment shown in FIG. There is an advantage that the shape can be changed greatly.
[0139]
Examples of the material used for the piezoelectric elements 409c and 409c ′ include piezoelectric substances such as barium titanate, Rossiel salt, crystal, tourmaline, potassium dihydrogen phosphate (KDP), ammonium dihydrogen phosphate (ADP), and lithium niobate. , Polycrystals of the same substance, crystals of the same substance, PbZrO_ThreeAnd PbTiO_ThreeThere are piezoelectric ceramics of solid solution, organic piezoelectric materials such as polyvinyl difluoride (PVDF), ferroelectric materials other than the above, especially organic piezoelectric materials have a low Young's modulus and can be deformed greatly even at low voltages. ,preferable. When these piezoelectric elements are used, it is possible to appropriately deform the shape of the thin film 409a in the above embodiment if the thickness is made non-uniform.
[0140]
The piezoelectric elements 409c and 409c ′ may be made of a piezoelectric material such as polyurethane, silicone rubber, acrylic elastomer, PZT, PLZT, polyvinylidene fluoride (PVDF), vinylidene cyanide copolymer, vinylidene fluoride and tri-vinyl chloride. A copolymer of fluoroethylene or the like is used.
When an organic material having piezoelectricity, a synthetic resin having piezoelectricity, an elastomer having piezoelectricity, or the like is used, a large deformation of the deformable mirror surface may be realized.
[0141]
When an electrostrictive material such as acrylic elastomer or silicon rubber is used for the piezoelectric element 409c in FIGS. 36 and 40, the piezoelectric element 409c is bonded to another substrate 409c-1 and the electrostrictive material 409c-2. It may be a different structure.
[0142]
FIG. 40 is a schematic diagram showing still another embodiment of the deformable mirror 409 applicable as a reflecting optical element having a reflecting surface for bending the zoom lens of the present invention.
In the deformable mirror of this embodiment, the piezoelectric element 409c is sandwiched between the thin film 409a and the electrode 409d, and a voltage is applied between the thin film 409a and the electrode 409d via the drive circuit 425 controlled by the arithmetic unit 414. In addition, separately from this, a voltage is also applied to the electrode 409b provided on the support base 423 via the drive circuit 425 controlled by the arithmetic unit 414. Therefore, in this embodiment, the thin film 409a can be deformed doubly by the voltage applied between the electrode 409d and the electrostatic force generated by the voltage applied to the electrode 409b. Therefore, there are advantages that more deformation patterns are possible and that the responsiveness is fast.
[0143]
If the sign of the voltage between the thin film 409a and the electrode 409d is changed, the deformable mirror can be deformed into a convex surface and a concave surface. In that case, a large deformation may be performed by the piezoelectric effect, and a minute shape change may be performed by electrostatic force. Further, the piezoelectric effect may be mainly used for the deformation of the convex surface, and the electrostatic force may be mainly used for the deformation of the concave surface. Note that the electrode 409d may be composed of a plurality of electrodes like the electrode 409b. This situation is shown in FIG. In the present application, the piezoelectric effect, the electrostrictive effect, and the electrostriction are collectively referred to as the piezoelectric effect. Therefore, an electrostrictive material is also included in the piezoelectric material.
[0144]
FIG. 41 is a schematic block diagram showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
The deformable mirror of the present embodiment can change the shape of the reflecting surface using electromagnetic force. A permanent magnet 426 is provided on the inner bottom surface of the support base 423, and silicon nitride is provided on the top surface. Alternatively, a peripheral portion of a substrate 409e made of polyimide or the like is placed and fixed, and a thin film 409a made of a metal coat such as aluminum is attached to the surface of the substrate 409e to constitute a deformable mirror 409. . A plurality of coils 427 are disposed on the lower surface of the substrate 409e, and these coils 427 are each connected to the arithmetic unit 414 via a drive circuit 428. Accordingly, an appropriate current is supplied from each drive circuit 428 to each coil 427 by an output signal from the arithmetic unit 414 corresponding to a change in the optical system required by the arithmetic unit 414 based on signals from the sensors 415, 416, 417, and 424. Is supplied, each coil 427 is repelled or attracted by an electromagnetic force acting between the permanent magnet 426 and deforms the substrate 409e and the thin film 409a.
[0145]
In this case, each coil 427 can flow a different amount of current. Further, the number of the coils 427 may be one, or the permanent magnet 426 may be attached to the substrate 409e and the coil 427 may be provided on the inner bottom surface side of the support base 423. The coil 427 may be made by a technique such as lithography, and the coil 427 may contain an iron core made of a ferromagnetic material.
[0146]
In this case, as shown in FIG. 42, the winding density of the thin film coil 427 can be changed depending on the location, whereby desired deformation can be given to the substrate 409e and the thin film 409a. One coil 427 may be provided, and an iron core made of a ferromagnetic material may be inserted into these coils 427.
[0147]
FIG. 43 is a schematic diagram showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention. In the figure, reference numeral 412 denotes a power source.
In the deformable mirror of this embodiment, the substrate 409e is made of a ferromagnetic material such as iron, and the thin film 409a as a reflective film is made of aluminum or the like. In this case, since it is not necessary to provide a thin film coil, the structure is simple and the manufacturing cost can be reduced. If the power switch 413 is replaced with a switching / power switch, the direction of the current flowing in the coil 427 can be changed, and the shapes of the substrate 409e and the thin film 409a can be freely changed. FIG. 44 shows the arrangement of the coil 427 in this embodiment, and FIG. 45 shows another arrangement example of the coil 427, but these arrangements can also be applied to the embodiment shown in FIG. 46 shows an arrangement of the permanent magnets 426 suitable for the case where the arrangement of the coil 427 is as shown in FIG. 45 in the embodiment shown in FIG. That is, as shown in FIG. 46, if the permanent magnets 426 are arranged radially, a subtle deformation can be given to the substrate 409e and the thin film 409a as compared with the embodiment shown in FIG. Further, when the substrate 409e and the thin film 409a are deformed by using the electromagnetic force as described above (the embodiment shown in FIGS. 41 and 43), there is an advantage that they can be driven at a lower voltage than when the electrostatic force is used.
[0148]
Although several embodiments of the deformable mirror have been described above, two or more kinds of forces may be used to deform the shape of the mirror as shown in the example of FIG. That is, the deformable mirror may be deformed by simultaneously using two or more of electrostatic force, electromagnetic force, piezoelectric effect, magnetostriction, fluid pressure, electric field, magnetic field, temperature change, electromagnetic wave, and the like. That is, if the optical characteristic variable optical element is made by using two or more different driving methods, large deformation and fine deformation can be realized at the same time, and an accurate mirror surface can be realized.
[0149]
FIG. 47 shows an imaging system using a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending a zoom lens according to still another embodiment of the present invention, for example, a digital camera of a mobile phone, It is a schematic block diagram of the imaging system used for an endoscope, an electronic endoscope, a digital camera for personal computers, a digital camera for PDAs, and the like.
In the imaging system of the present embodiment, the reflective optical element R1 in the optical configuration shown in the first embodiment is configured by a deformable mirror 409. These zoom lenses, the CCD 408 that is an electronic image pickup device, and the control system 103 constitute one image pickup unit 104. In the imaging unit 104 of the present embodiment, a negative meniscus lens L1 having a convex surface facing the object side.₁The light from the object that has passed through is condensed by the deformable mirror 409, and is a biconvex positive lens L1.₂The image is formed on the CCD 408, which is a solid-state imaging device, through the second lens group G2, the third lens group G3, the fourth lens group G4, and the CCD cover glass CG. The deformable mirror 409 is a kind of optical characteristic variable optical element, and is also called a variable focus mirror.
[0150]
According to this embodiment, even if the object distance changes, it is possible to focus by deforming the deformable mirror 409, it is not necessary to drive the lens with a motor or the like, and the size, weight, and power consumption are reduced. Excellent in terms of conversion. The imaging unit 104 can be used in all embodiments as an imaging system of the present invention. Also, by using a plurality of deformable mirrors 409, it is possible to make a zoom and variable magnification imaging system and optical system.
FIG. 47 shows a configuration example of a control system including a transformer booster circuit using coils in the control system 103. In particular, when a laminated piezoelectric transformer is used, the size can be reduced. Although the booster circuit can be used for the deformable mirror using all electricity of the present invention, it is particularly useful for the deformable mirror when the electrostatic force and the piezoelectric effect are used. In order to perform focusing with the deformable mirror 409, for example, an object image is formed on the solid-state imaging device 408, and the high frequency component of the object image is maximized while changing the focal length of the deformable mirror 409. Find it. In order to detect a high-frequency component, a processing circuit including a microcomputer or the like is connected to the solid-state image sensor 408, and the high-frequency component may be detected therein.
[0151]
The electronic imaging apparatus using the folding zoom lens of 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 imaging element such as a CCD or a silver salt film. It can be used for a photographing apparatus that performs the above, especially a digital camera, a video camera, a personal computer which is an example of an information processing apparatus, a telephone, especially a mobile phone which is convenient to carry. The embodiment is illustrated below.
[0152]
48 to 50 are conceptual views of a configuration in which the folding zoom lens according to the present invention is incorporated in the photographing optical system 41 of the digital camera. FIG. 48 is a front perspective view showing the appearance of the digital camera 40, and FIG. 50 and 50 are cross-sectional views showing the configuration of the digital camera 40. FIG. The digital camera shown in FIG. 50 has a configuration in which the imaging optical path is bent in the long side direction of the finder, and the observer's eyes in FIG. 50 are shown as viewed from above.
[0153]
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, the photographing is performed through the photographing optical system 41, for example, the optical path bending zoom lens of the first embodiment in conjunction therewith.
The object image formed by the photographing optical system 41 is formed on the imaging surface of the CCD 49 through a near infrared cut filter or a near infrared cut coat applied to a CCD cover glass or other lens.
[0154]
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 unit 52 may be provided separately from the processing unit 51, or may be configured to perform recording and writing electronically using a floppy (registered trademark) disk, a memory card, an 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.
[0155]
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. Cover members 50 are disposed on the incident side of the photographing optical system 41 and the objective optical system 53 for the viewfinder and on the exit side of the eyepiece optical system 59, respectively.
[0156]
The digital camera 40 configured in this way is effective in reducing the thickness of the camera by placing and bending the optical path in the long side direction. Further, since the photographing optical system 41 is a zoom lens having a wide angle of view and a high zoom ratio, good aberration, bright, and a large back focus on which a filter or the like can be arranged, high performance and low cost can be realized.
Note that the imaging optical path of the digital camera 40 of this embodiment may be configured to bend in the short side direction of the viewfinder. In that case, a strobe (or flash) may be arranged further upward from the entrance surface of the photographic lens, so that the layout can reduce the influence of shadows that occur when a person takes a stroboscope.
In the example of FIG. 50, a parallel plane plate is disposed as the cover member 50, but a lens having power may be used.
[0157]
Next, a personal computer as an example of an information processing apparatus in which the folding zoom lens of the present invention is incorporated as an objective optical system is shown in FIGS. 51 is a front perspective view with the cover of the personal computer 300 opened, FIG. 52 is a sectional view of the photographing optical system 303 of the personal computer 300, and FIG. 53 is a side view of FIG.
[0158]
As shown in FIGS. 51 to 53, a personal computer 300 includes a keyboard 301 for an operator to input information from the outside, an information processing means and a recording means (not shown), and a monitor 302 for displaying information to the operator. 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. In the drawing, the photographic optical system 303 is built in the upper right of the monitor 302, but is not limited to that location, and may be anywhere around the monitor 302 or the keyboard 301.
This photographic optical system 303 has, on the photographic optical path 304, an objective lens 112 made of, for example, an optical path bending zoom lens according to the first embodiment of the present invention, and an image sensor chip 162 that receives an image. These are built in the personal computer 300.
[0159]
Here, a cover glass CG is additionally attached on the image pickup device chip 162 to be integrally formed as the 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.
[0160]
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 displayed on the monitor 302 as an electronic image. FIG. 51 shows an image 305 taken by the operator as an example. 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.
[0161]
Next, FIG. 54 shows a telephone which is an example of an information processing apparatus in which the folding zoom lens of the present invention is incorporated as a photographing optical system, particularly a portable telephone which is convenient to carry. 54 (a) is a front view of the mobile phone 400, FIG. 54 (b) is a side view, and FIG. 54 (c) is a sectional view of the photographing optical system 405.
As shown in FIGS. 54 (a) to 54 (c), 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 the operator receives information. An input dial 403 for input, a monitor 404 for displaying information such as a photographed image and 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 image information And processing means (not shown) for processing 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 photographic optical system 405 includes an objective lens 112 including, for example, an optical path bending zoom lens according to the first embodiment of the present invention disposed on a photographic optical path 407, and an imaging element chip 162 that receives an object image. . These are built in the mobile phone 400.
[0162]
Here, a cover glass CG is additionally attached on the image pickup device chip 162 to be integrally formed as the 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.
[0163]
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.
[0199]
【The invention's effect】
According to the present invention, a reflection optical element such as a mirror is inserted on the object side as much as possible to bend the optical path (optical axis) of the optical system, particularly the zoom lens system, and so that various conditional expressions are satisfied. While maintaining high optical performance such as zoom ratio, angle of view, F-number, and low aberration, there is no camera startup time (lens protrusion time) as seen with a retractable lens barrel, and it is waterproof -It is preferable from the viewpoint of dust prevention, and a camera with a very thin depth direction can be realized. In addition, unlike other zoom optical systems such as a zoom lens suitable for a retractable lens barrel, if the size of the image sensor is reduced in the future, the camera will be further miniaturized when the reduced image sensor is used. And thinning can be advantageously promoted.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken along an optical axis showing an optical configuration according to a first embodiment of a zoom lens used in an electronic imaging device according to the present invention, showing a state at the time of folding when focusing on an object point at infinity at a wide angle. ing.
FIGS. 2A and 2B are cross-sectional views along the optical axis showing the optical configuration of the zoom lens according to the first embodiment when focusing on an object point at infinity, where FIG. 2A is a wide angle end, FIG. Indicates the state at the telephoto end.
FIG. 3 is a diagram showing spherical aberration, astigmatism, distortion aberration, and chromatic aberration of magnification when the zoom lens according to Example 1 is focused on an object point at infinity, and shows a state at the wide-angle end.
FIG. 4 is a diagram illustrating spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens according to Example 1 is focused on an object point at infinity, and shows an intermediate state.
FIG. 5 is a diagram showing spherical aberration, astigmatism, distortion aberration, and chromatic aberration of magnification when the zoom lens according to Example 1 is focused on an object point at infinity, and shows a state at the telephoto end.
FIG. 6 is a cross-sectional view along the optical axis showing an optical configuration according to a second embodiment of the zoom lens used in the electronic image pickup apparatus according to the present invention, showing a state at the time of folding when focusing on an object point at infinity at the wide angle. ing.
FIGS. 7A and 7B are cross-sectional views along the optical axis showing the optical configuration of the zoom lens according to the second embodiment when focusing on an object point at infinity, where FIG. 7A is a wide angle end, FIG. Indicates the state at the telephoto end.
FIG. 8 is a sectional view along an optical axis showing an optical configuration according to a third example of the zoom lens used in the electronic imaging device according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at the wide angle. ing.
FIGS. 9A and 9B are cross-sectional views along the optical axis showing the optical configuration of the zoom lens according to the third example when focusing on an object point at infinity, where FIG. 9A is a wide-angle end, FIG. Indicates the state at the telephoto end.
FIG. 10 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens according to Example 3 is focused on an object point at infinity, and shows a state at the wide-angle end.
FIG. 11 is a diagram illustrating spherical aberration, astigmatism, distortion, and lateral chromatic aberration when the zoom lens according to Example 3 is focused on an object point at infinity, and shows an intermediate state.
12 is a diagram showing spherical aberration, astigmatism, distortion aberration, and chromatic aberration of magnification when the zoom lens according to Example 3 is focused on an object point at infinity, and shows a state at a telephoto end. FIG.
FIG. 13 is a cross-sectional view along the optical axis showing an optical configuration according to a fourth example of the zoom lens used in the electronic imaging device according to the present invention, and shows a state at the time of bending when focusing on an object point at infinity at the wide angle end; ing.
FIGS. 14A and 14B are cross-sectional views along the optical axis showing the optical configuration of the zoom lens according to the fourth example when focusing on an object point at infinity, where FIG. 14A is a wide-angle end, FIG. Indicates the state at the telephoto end.
FIG. 15 is a diagram illustrating spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens according to Example 4 is focused on an object point at infinity, and shows a state at the wide-angle end.
FIG. 16 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens according to Example 4 is focused on an object point at infinity, and shows an intermediate state.
FIG. 17 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens according to Example 4 is focused on an object point at infinity, and shows a state at the telephoto end.
FIG. 18 is a sectional view taken along an optical axis showing an optical configuration according to a fifth embodiment of the zoom lens used in the electronic imaging device according to the present invention, and showing a state at the time of folding when focusing on an object point at infinity at a wide angle. ing.
FIGS. 19A and 19B are cross-sectional views along the optical axis showing the optical configuration of the zoom lens according to the fifth example when focusing on an object point at infinity, where FIG. 19A is a wide-angle end, FIG. Indicates the state at the telephoto end.
FIG. 20 is a cross-sectional view along the optical axis showing an optical configuration according to a sixth example of the zoom lens used in the electronic imaging device according to the present invention, and shows a state at the time of folding when focusing on an object point at infinity at the wide angle end; ing.
FIGS. 21A and 21B are cross-sectional views along the optical axis showing the optical configuration of the zoom lens according to the sixth example when focusing on an object point at infinity, where FIG. 21A is a wide angle end, FIG. Indicates the state at the telephoto end.
FIG. 22 is a sectional view taken along an optical axis showing an optical configuration according to a seventh embodiment of the zoom lens used in the electronic imaging device according to the present invention, and showing a state at the time of folding at the time of focusing on an object point at infinity at a wide angle. ing.
FIG. 23 is a cross-sectional view along the optical axis showing the optical configuration of the zoom lens according to the seventh example when focusing on an object point at infinity, (a) is a wide angle end, (b) is an intermediate, (c) Indicates the state at the telephoto end.
FIG. 24 is an explanatory diagram showing an example of a pixel array of an electronic image sensor used in each embodiment of the present invention.
FIG. 25 is a graph showing transmittance characteristics of an example of a near-infrared sharp cut coat.
FIG. 26 shows transmittance characteristics of an example of a color filter provided on the exit surface side of a CCD cover glass CG having a near infrared cut coat or on the exit surface side of another lens having a near infrared cut coat. It is a graph.
FIG. 27 is a diagram illustrating a color filter arrangement of a complementary color mosaic filter.
FIG. 28 is a graph illustrating an example of wavelength characteristics of a complementary color mosaic filter.
FIG. 29 is an explanatory diagram showing a modified example of the diaphragm S used in the electronic imaging apparatus according to each embodiment of the present invention.
FIG. 30 is an explanatory diagram illustrating an example of a light amount adjusting unit used in the electronic imaging apparatus according to each embodiment of the present invention.
FIG. 31 is a perspective view showing a specific example of a state in which the light amount adjusting means shown in FIG. 30 is applied to the present invention.
FIG. 32 is an explanatory view showing another example of the light amount adjusting means applicable to the electronic imaging apparatus according to each embodiment of the present invention.
FIG. 33 is an explanatory diagram showing still another example of the light amount adjusting means applicable to the electronic imaging device according to each embodiment of the invention.
FIG. 34 is a schematic configuration diagram showing an example of a rotary focal plane shutter that is one of focal plane shutters for adjusting a light receiving time applicable to the electronic imaging device according to each embodiment of the present invention, and A back view and (b) are front views.
FIGS. 35A to 35D are views of the rotary shutter curtain B shown in FIG. 34 as viewed from the image plane side.
FIG. 36 is a schematic configuration diagram showing an example of a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
37 is an explanatory view showing one form of electrodes used in the deformable mirror of the embodiment of FIG. 36. FIG.
FIG. 38 is an explanatory view showing another form of the electrodes used in the deformable mirror of the embodiment of FIG. 36.
FIG. 39 is a schematic configuration diagram showing still another embodiment of the deformable mirror 409 applicable as a reflecting optical element having a reflecting surface for bending the zoom lens of the present invention.
FIG. 40 is a schematic configuration diagram showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
FIG. 41 is a schematic configuration diagram showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
42 is an explanatory diagram showing a state of a winding density of the thin film coil 427 in the embodiment of FIG. 41. FIG.
FIG. 43 is a schematic configuration diagram showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
44 is an explanatory diagram showing an arrangement example of a coil 427 in the embodiment of FIG. 43. FIG.
45 is an explanatory view showing another arrangement example of the coil 427 in the embodiment of FIG. 43. FIG.
46 is an explanatory diagram showing an arrangement of permanent magnets 426 suitable for the case where the arrangement of the coil 427 is as shown in FIG. 45 in the embodiment shown in FIG. 41. FIG.
47 shows an imaging system using a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending a zoom lens according to still another embodiment of the present invention, for example, a digital camera of a mobile phone, a capsule; It is a schematic block diagram of the imaging system used for an endoscope, an electronic endoscope, a digital camera for personal computers, a digital camera for PDAs, and the like.
FIG. 48 is a conceptual diagram of a configuration in which a folding zoom lens according to the present invention is incorporated in a photographing optical system 41 of a digital camera, and is a front perspective view showing an appearance of the digital camera 40.
49 is a rear perspective view of the digital camera 40 shown in FIG. 48. FIG.
50 is a cross-sectional view showing a configuration of the digital camera 40 shown in FIG. 48. FIG.
FIG. 51 is a front perspective view in which a cover of a personal computer 300 which is an example of an information processing apparatus in which a folding zoom lens of the present invention is incorporated as an objective optical system is opened.
52 is a sectional view of the photographing optical system 303 of the personal computer 300 shown in FIG. 51. FIG.
53 is a side view of FIG. 51. FIG.
54A and 54B are diagrams showing a mobile phone as an example of an information processing apparatus in which the folding zoom lens of the present invention is built in as a photographing optical system, where FIG. 54A is a front view of the mobile phone 400, and FIG. (C) is a cross-sectional view of the photographing optical system 405.
[Explanation of symbols]
A Shutter board
A1 substrate opening
B Rotary shutter curtain
C Rotary shaft of rotary shutter curtain
D1, D2 gear
CG CCD cover glass
E Observer eyeball
G1 first lens group
G2 Second lens group (first moving lens group)
G3 third lens group (second moving lens group)
G4 4th lens group
I Imaging surface
L1₁         Negative meniscus lens with convex surface facing the object
L1₂         Biconvex positive lens
L2₁         Biconcave negative lens
L2₂         Positive meniscus lens with convex surface facing the object
L3₁         Biconvex positive lens
L3₂         Biconcave negative lens
L3₂′ Biconvex positive lens
L3_Three         Positive meniscus lens with convex surface facing the object
L3_Three′ Biconcave negative lens
L4₁         Positive meniscus lens with concave surface facing the object
L4₁′ Biconcave negative lens
L4₁”Negative meniscus lens with convex surface facing the object
L4₁"" Positive meniscus lens with convex surface facing the object
L4₁"" Biconvex positive lens
L4₂         Biconvex positive lens
R1 reflective optical element
S Aperture stop
1A, 1B, 1C, 1D opening
10 Turret
11 Rotating shaft
40 Digital camera
41 Imaging optical system
42 Optical path for shooting
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 Field frame
59 Eyepiece optical system
103 Control system
104 Imaging unit
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 Imaging optical system
304 Shooting optical path
305 images
400 mobile phone
401 Microphone
402 Speaker unit
403 input dial
404 monitor
405 Imaging optical system
406 Antenna
407 Shooting optical path
408 Solid-state image sensor
409b, 409d electrode
409c-2 Electrostrictive material
409 Optical property variable shape mirror
409a thin film
409c, 409c 'piezoelectric element
409c-1, 409e substrate
411 Variable resistor
412 power supply
413 Power switch
414 Arithmetic unit
415 Temperature sensor
416 Humidity sensor
417 Distance sensor
423 Support stand
424 Runout sensor
425, 428 drive circuit
426 Permanent magnet
427 coil

Claims (39)

The most object side lens group which is located on the most object side and is fixed on the optical axis at the time of zooming and focusing operation;
The most image side lens group which is located on the most image side and is fixed on the optical axis at least during focusing operation;
Wherein comprises a first moving lens unit and the second moving lens group moves along the optical axis when located, zooming between the most object side lens group and the most image-side lens unit,
The most object side lens group has a positive refractive power, the first moving lens group has a negative refractive power, the second moving lens group has a positive refractive power, and the most image side lens group has a positive refractive power. And
The most object side lens group, in order from the object side, is composed of a negative lens component, a surface mirror having a reflecting surface for bending the optical path, and a positive lens component,
The most image side lens group has at least one aspheric surface;
A zoom lens satisfying the following conditional expression:
0.9 <−f11 / √ (fw · fT) <2.4
1.6 <f12 / √ (fw · fT) <3.6
Where f11 is the focal length of the negative lens component in the most object side lens group, f12 is the focal length of the positive lens component in the most object side lens group, and fw is the focal length of the entire system at the wide angle end of the zoom lens. , FT is the focal length of the entire system at the telephoto end of the zoom lens. In order from the object side, the first lens group as the most object side lens group having positive refractive power and fixed at the time of zooming;
A second lens group as a first moving lens group having negative refractive power and moving on the optical axis at the time of zooming;
A third lens group as a second moving lens group having a positive refractive power and moving on the optical axis at the time of zooming;
It has a positive refractive power consists of a most image-side lens unit located closest to the image side,
The first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending the optical path, and a positive lens component.
The reflective surface is variable in shape,
A zoom lens satisfying the following conditional expression:
0.9 <−f11 / √ (fw · fT) <2.4
1.6 <f12 / √ (fw · fT) <3.6
Where f11 is the focal length of the negative lens component in the most object side lens group, f12 is the focal length of the positive lens component in the most object side lens group, and fw is the focal length of the entire system at the wide angle end of the zoom lens. , FT is the focal length of the entire system at the telephoto end of the zoom lens. At the time of zooming from the wide-angle end to the telephoto end at the time infinite far object point focusing, claim 2, wherein the second lens group moves back and forth along a locus convex on the optical axis toward the image side Zoom lens described in 1 .   The zoom lens according to claim 1, wherein a focusing operation is performed by changing a shape of the reflecting surface. The reflective surface is composed of a thin film coated with metal or dielectric,
The thin film is connected to a power source through a plurality of electrodes and a variable resistor,
An arithmetic device for controlling a variable resistance value of the variable resistor;
The zoom lens according to claim 1, wherein the shape of the reflecting surface is made variable by controlling the distribution of electrostatic force applied to the thin film. The third lens group is composed of three lenses, and the three lenses are composed of a cemented lens component in which a positive lens and a negative lens are cemented and two lens components of a single lens, or Consists of one lens component consisting of three cemented lenses,
6. The zoom lens according to claim 2, wherein the zoom lens moves only to the object side when zooming from the wide-angle end to the telephoto end.   3. The zoom lens according to claim 1, wherein the negative lens component in the most object side lens group is configured by a negative single lens, and the positive lens component is configured by a positive single lens.   The first lens group has a positive refractive power, the third lens group moves only to the object side during zooming, the most image side lens group includes an aspherical surface, and is fixed during zooming. The zoom lens according to claim 3, wherein: The zoom lens according to claim 2, wherein the following conditional expression is satisfied.
0.3 <−βRw <0.8
0.8 <fRw / √ (fw · fT) <2.0
Where βRw is the combined magnification after the third lens group at the wide-angle end when focusing on an object point at infinity, and fRw is the combined focal length after the third lens group at the wide-angle end when focusing on an object point at infinity. , Fw is the focal length of the entire system at the wide-angle end of the zoom lens, and fT is the focal length of the entire system at the telephoto end of the zoom lens.   The third lens group includes three lenses, and the three lenses include a single lens and a cemented lens component in which a positive lens and a negative lens are cemented in order from the object side. The zoom lens according to any one of claims 2 to 6.   The third lens group includes three lenses, and the three lenses include a cemented lens component in which a positive lens and a negative lens are cemented in order from the object side, and a single lens. The zoom lens according to any one of claims 2 to 6.   The third lens group includes three lenses, and the three lenses include a three-piece cemented lens component in which a positive lens, a negative lens, and a positive lens are cemented in order from the object side. The zoom lens according to claim 2. The zoom lens according to claim 10, wherein the following conditional expression is satisfied.
0.4 < _RC3 / _RC1 <0.8
Where R _C3 is the radius of curvature on the optical axis of the most image side surface of the cemented lens component in the third lens group, and R _C1 is the most object side surface of the cemented lens component in the third lens group. The radius of curvature on the optical axis. In order from the object side, the first lens group as the most object side lens group having positive refractive power and fixed at the time of zooming;
A second lens group as a first moving lens group having negative refractive power and moving on the optical axis at the time of zooming;
A third lens group as a second moving lens group having a positive refractive power and moving on the optical axis at the time of zooming;
It has a positive refractive power consists of a most image-side lens unit located closest to the image side,
The first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending the optical path, and a positive lens component.
The reflective surface is variable in shape,
The third lens group is composed of three lenses, and the three lenses are composed of a cemented lens component in which a positive lens and a negative lens are cemented in order from the object side, and a single lens.
A zoom lens satisfying the following conditional expression:
1.0 < _RC3 / _RC1 <10
Where R _C3 is the radius of curvature on the optical axis of the most image side surface of the cemented lens component in the third lens group, and R _C1 is the most object side surface of the cemented lens component in the third lens group. The radius of curvature on the optical axis. In order from the object side, the first lens group as the most object side lens group having positive refractive power and fixed at the time of zooming;
A second lens group as a first moving lens group having negative refractive power and moving on the optical axis at the time of zooming;
A third lens group as a second moving lens group having a positive refractive power and moving on the optical axis at the time of zooming;
It has a positive refractive power consists of a most image-side lens unit located closest to the image side,
The first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending the optical path, and a positive lens component.
The reflective surface is variable in shape,
The third lens group is composed of three lenses, and the three lenses are composed of a three-piece cemented lens component in which a positive lens, a negative lens, and a positive lens are cemented in order from the object side.
A zoom lens satisfying the following conditional expression:
−4.0 <(R _CF + R _CR ) / (R _CF −R _CR ) <0
Where R _CF is the radius of curvature of the three-piece cemented lens component on the optical axis of the surface closest to the object, and R _CR is the radius of curvature of the three-piece cemented lens component on the optical axis of the surface closest to the image side. is there. The zoom lens according to claim 12, wherein the following conditional expression is satisfied.
0.6 <Dc / fw <1.8
Here, Dc is the distance on the optical axis from the most object side surface to the most image side surface of the three-piece cemented lens component, and fw is the focal length of the entire system at the wide angle end of the zoom lens. The zoom lens according to claim 12, 15 or 16, wherein the following conditional expression is satisfied.
0.002 / mm ² <Σ | (1 / Rci) − (1 / Rca) | ² <0.05 mm ²
Where Rci is the radius of curvature on the optical axis of the i-th cemented surface from the object side of the three-piece cemented lens component, and Rca is Rca = m / | Σ (1 / Rci) | (i = 1... M) Here, m is 2 of the number of joint surfaces. The zoom lens according to claim 12, wherein the zoom lens satisfies the following conditional expression.
5 × 10 ⁻⁵ <Σ | (1 / νcj + 1) − (1 / νcj) | ² <4 × 10 ⁻³
Where νcj is the Abbe number of the medium with respect to the i-th d-line reference from the object side of the three-piece cemented lens component, j = 1... N−1, where n is three of the number of lenses to be joined. is there. The zoom lens according to claim 12, wherein the following conditional expression is satisfied.
0.005 <Σ | ncj + 1−ncj | ² <0.5
Here, ncj is the refractive index of the medium with respect to the i-th d-line reference from the object side of the three-piece cemented lens component, j = 1... N−1, where n is three of the number of lenses to be joined. is there.   The zoom lens according to claim 1, wherein the negative lens component of the most object side lens group is an aspherical surface. The zoom lens according to claim 20, wherein the following conditional expression is satisfied.
_{-2.5 <(R 1PF + R 1PR} ) / (R 1PF -R 1PR) <0.6
However, R _1PF is the radius of curvature on the optical axis of the object side surface of the positive lens component of the most object side lens group, R _{1 PR} is on the optical axis of the image side surface of the positive lens component of the most object side lens group Is the radius of curvature.   3. The zoom lens according to claim 2, wherein the second lens group includes two lenses of a negative lens and a positive lens in order from the object side.   23. The zoom lens according to claim 22, wherein the second lens group is a cemented lens component composed of a negative lens and a positive lens in order from the object side. In order from the object side, the first lens group as the most object side lens group having positive refractive power and fixed at the time of zooming;
A second lens group as a first moving lens group having negative refractive power and moving on the optical axis at the time of zooming;
A third lens group as a second moving lens group having a positive refractive power and moving on the optical axis at the time of zooming;
It has a positive refractive power consists of a most image-side lens unit located closest to the image side,
The first lens group includes, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending the optical path, and a positive lens component.
The reflective surface is variable in shape,
The second lens group is a cemented lens component composed of two lenses of a negative lens and a positive lens in order from the object side,
A zoom lens satisfying the following conditional expression:
−1.6 <(R _2F + R _2R ) / (R _2F −R _2R ) <0.3
Where R _2F is a radius of curvature on the optical axis of the surface closest to the object side of the second lens group (junction lens component), and R _2R is a surface closest to the image side of the second lens group (junction lens component). The radius of curvature on the optical axis. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
1.8 <fT / fw
Here, fT is the focal length of the entire zoom lens system at the telephoto end, and fw is the focal length of the entire zoom lens system at the wide angle end.   An electronic imaging apparatus comprising: the zoom lens according to claim 1; and an electronic imaging device disposed on an image side thereof. 27. The electronic imaging apparatus according to claim 26, wherein the following conditional expression is satisfied, where a is a horizontal pixel pitch of the electronic imaging element and F is an open F value at the wide-angle end of the zoom lens. .
F ≧ a / (1 μm)   The inner diameter of the aperture stop that determines the open F value is fixed, and is provided with a lens having a convex surface facing the stop immediately before or after the stop, and an optical axis and a lower surface from the aperture stop to the optical axis. 28. The electronic imaging apparatus according to claim 27, wherein an intersection with the perpendicular line is located within 0.5 mm from the inside of the lens or the vertex of the convex surface.   29. The electronic imaging apparatus according to claim 28, wherein the intersection point is located within the lens or within the surface apex.   A transmittance variable means for adjusting the amount of light guided to the electronic image pickup device by changing the transmittance is provided, and the transmittance variable means is disposed in an optical path in a space different from the space in which the diaphragm is disposed. 30. The electronic imaging device according to claim 27, wherein   31. The apparatus according to claim 27, further comprising a shutter for adjusting a light receiving time of the light beam guided to the electronic image pickup device, wherein the shutter is disposed in an optical path in a space different from a space in which the diaphragm is disposed. The electronic imaging device in any one.   32. The electronic imaging apparatus according to claim 26, wherein no low-pass filter is disposed in an optical path from the incident surface of the optical system to the imaging surface.   32. Each medium boundary surface disposed between the zoom lens and the imaging surface is substantially flat, and has no spatial frequency conversion effect unlike an optical low-pass filter. The electronic imaging device according to any one of the above. 27. The electronic imaging apparatus according to claim 26, wherein the following conditional expression is satisfied.
1.4 <d / L <3.0
Where d is an air-converted length measured along the optical axis from the image side apex of the negative lens component to the object side apex of the positive lens component in the most object side lens group, and L is effective imaging of the electronic image sensor. The diagonal length of the region. 35. The electronic imaging apparatus according to claim 34, wherein the negative lens component of the most object side lens group is constituted by a negative single lens, and satisfies the following conditional expression.
26 <ν1N
−0.1 <√ (fw · fT) / f1 <0.6
Where ν1N is the Abbe number on the d-line basis of the medium of the negative single lens in the most object side lens group, f1 is the focal length of the most object side lens group, and fw is the entire system at the wide angle end of the zoom lens. Is the focal length of the entire system at the telephoto end of the zoom lens. An electronic imaging apparatus comprising: the zoom lens according to claim 10 or 13; and an electronic imaging device disposed on an image side thereof, wherein the following conditional expression is satisfied.
-0.7 <L / R _C2 <0.1
15 <ν _CP − ν _CN
However, L is the diagonal length (mm) of the image sensor. It is assumed that the image sensor is used so that the wide angle end angle of view includes 55 degrees or more. R _C2 is the radius of curvature on the optical axis of the cemented surface of the cemented lens component in the third lens group, ν _CP is the Abbe number of the positive lens medium of the cemented lens component in the third lens group, and ν _CN is It is an Abbe number of the medium of the negative lens in the cemented lens component of the third lens group. 15. An electronic imaging apparatus comprising: the zoom lens according to claim 11 or 14; and an electronic imaging device disposed on an image side thereof, wherein the following conditional expression is satisfied.
-1.1 <L / R _C2 <0
15 <ν _CP − ν _CN
However, L is the diagonal length (mm) of the image sensor. It is assumed that the image sensor is used so that the wide angle end angle of view includes 55 degrees or more. R _C2 is the radius of curvature on the optical axis of the cemented surface of the cemented lens component in the third lens group, ν _CP is the Abbe number of the positive lens medium of the cemented lens component in the third lens group, and ν _CN is It is an Abbe number of the medium of the negative lens in the cemented lens component of the third lens group.   38. The electronic image pickup apparatus according to claim 26, wherein a full angle of view at the wide-angle end in the electronic image pickup apparatus is 55 degrees or more.   39. The electronic imaging apparatus according to claim 38, wherein a wide angle end full angle of view in the electronic imaging apparatus is 80 degrees or less.

Images