JP4205464B2 - Zoom lens, imaging device, and portable information terminal device - Google Patents

Description

【００４３】
また、以下に述べる数値例においてＥ−ＸＹは、１０^−ＸＹを意味している。さらに、以下に説明する収差図については、球面収差において、実線が球面収差、破線が正弦条件をあらわし、非点収差において、実線がサジタル像面、破線がメリディオナル像面をあらわす。また、実線の一方の線はｄ線（５８７．５６ｎｍ）、そして他方の実線はｇ線（４３５．８３ｎｍ）をあらわしている。
【００４４】
〔第１の実施例〕
図１は、本発明の第１の実施例に係るズームレンズの光学系の構成を示している。
図１に示すズームレンズは、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１、絞りＦＡおよび光学フィルタ（カバーガラスを含む）ＯＦを具備している。この場合、第１レンズＥ１〜第３レンズＥ３は、第１群光学系Ｇ１を構成し、第４レンズＥ４〜第６レンズＥ６は、第２群光学系Ｇ２を構成し、第７レンズＥ７〜第１１レンズＥ１１は、第３群光学系Ｇ３を構成しており、それぞれ各レンズ群毎に適宜なる共通の支持枠等によって支持され、ズーミング等に際しては各レンズ群毎に一体的に動作する。
また、絞りＦＡは、第３群光学系Ｇ３の物体側に配置されており、第３群光学系Ｇ３と一体的に動作する。図１には、参考のために各光学面の面番号も付して示している。なお、図１に対する各参照符号は、参照符号の桁数の増大による説明の煩雑化を避けるため、各実施例毎に独立に用いており、そのため共通の参照符号を付していても他の実施例とかならずしも共通の構成ではない。
【００４５】
図１において、例えば被写体等の物体側から、順次、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、絞りＦＡ、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１および光学フィルタＯＦの順で配列されており、各種の光学フィルタリング機能を有する光学フィルタＯＦの背後に結像される。
第１レンズＥ１は、物体側に凸に形成された負メニスカスレンズ、第２レンズＥ２は、物体側に凸に形成された正メニスカスレンズ、そして第３レンズＥ３は、物体側に凸に形成された正メニスカスレンズであり、第１レンズＥ１と第２レンズＥ２は、密に接合された２枚接合レンズであって、これら第１レンズＥ１〜第３レンズＥ３により構成する第１群光学系Ｇ１は、全体として正の焦点距離を呈する。
【００４６】
第４レンズＥ４は、物体側に凸に形成された負メニスカスレンズ、第５レンズＥ５は、両凹レンズからなる負レンズ、そして第６レンズＥ６は、物体側に凸に形成された正メニスカスレンズであり、第５レンズＥ５と第６レンズＥ６は、密に接合された２枚接合レンズであって、これら第４レンズＥ４〜第６レンズＥ６により構成する第２群光学系Ｇ２は、全体として負の焦点距離を呈する。第７レンズＥ７は、両凸レンズからなる正レンズ、第８レンズＥ８は、 物体側に凸に形成された負メニスカスレンズ、第９レンズＥ９は、両凸レンズからなる正レンズ、第１０レンズＥ１０は、両凹レンズからなる負レンズ、そして第１１レンズＥ１１は、両凸レンズからなる正レンズであり、第８レンズＥ８〜第１０レンズＥ１０は、密に接合された３枚接合レンズであって、これら第７レンズＥ７〜第１１レンズＥ１１により構成する第３群光学系Ｇ３は、全体として正の焦点距離を呈する。第２群光学系Ｇ２と第３群光学系Ｇ３との間に配置された絞りＦＡは、第３群光学系Ｇ３と一体的に動作し、第３群光学系Ｇ３との間の距離は一定である。
【００４７】
第３群光学系Ｇ３の第１１レンズＥ１１の像面側に配置された光学フィルタＯＦは、ＣＣＤ撮像素子等の固体撮像素子５３のカバーガラスを含んでいてもよく、各種の光学フィルタリング機能を有する。この第１の実施例では、第２群光学系Ｇ２の最も物体側に位置する第４レンズＥ４の物体側の面である第６面および第３群光学系Ｇ３の最も物体側に位置する第７レンズＥ７の物体側の面である第１２面をそれぞれ非球面としている。
広角端、つまり短焦点距離端、と望遠端、つまり長焦点距離端、との間での変倍に伴う各群光学系Ｇ１〜Ｇ３の移動は、図１に示されるように、第２群光学系Ｇ２は、移動せずに像面に対して固定しており、短焦点距離端から長焦点距離端への移動に伴って、第１群光学系Ｇ１が像面側から物体側へ向かって移動し、第３群光学系Ｇ３も像面側から物体側へ向かって移動する。
この第１の実施例においては、全系の焦点距離ｆ、ＦナンバＦ、そして半画角ωは、ズーミングにより、それぞれｆ＝５．９０２〜１７．７０７，Ｆ＝３．３７〜４．４１，ω＝３８．２〜１４．７の範囲で変化する。各光学面および光学素子に関連する光学特性は、次表の通りである。＊の付されたレンズ面は非球面とされていることを示す。
【００４８】
【表１】
〈光学特性〉

【００４９】
表１における第６面および第１２面の各光学面が非球面であり、各非球面における先に述べた式（４）に係るパラメータは、次表の通りである。
【００５０】
【表２】
〈非球面係数〉

第１群光学系Ｇ１と第２群光学系Ｇ２との間の間隔ｄ１、第２群光学系Ｇ２と絞りＦＡとの間の間隔ｄ２、そして第３群光学系Ｇ３と光学フィルタＯＦとの間の間隔ｄ３は、可変であり、これら可変間隔ｄ１、ｄ２およびｄ３は、ズーミングに伴って、全系の焦点距離ｆに対応して次表のように変化させられる。
【００５１】
【表３】
〈可変間隔〉

また、この第１の実施例における先に述べた本発明の各条件式（１）〜（３）に係るパラメータの値は、次表の通りとなり、各条件式の範囲内である。
【００５２】
【表４】
〈条件式のパラメータ値〉

この第１の実施例における収差図を図８に示している。
【００５３】
〔第２の実施例〕
図２は、本発明の第２の実施例に係るズームレンズの光学系の構成を示している。
図２に示すズームレンズは、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１、絞りＦＡおよび光学フィルタ（カバーガラスを含む）ＯＦを具備している。この場合、第１レンズＥ１〜第３レンズＥ３は、第１群光学系Ｇ１を構成し、第４レンズＥ４〜第６レンズＥ６は、第２群光学系Ｇ２を構成し、第７レンズＥ７〜第１１レンズＥ１１は、第３群光学系Ｇ３を構成しており、それぞれ各レンズ群毎に適宜なる共通の支持枠等によって支持され、ズーミング等に際しては各レンズ群毎に一体的に動作する。また、絞りＦＡは、第３群光学系Ｇ３の物体側に配置されており、第３群光学系Ｇ３と一体的に動作する。図２には、各光学面の面番号も付して示している。
なお、図２に対する各参照符号は、参照符号の桁数の増大による説明の煩雑化を避けるため、各実施例毎に独立に用いており、そのため共通の参照符号を付していても他の実施例とかならずしも共通の構成ではない。
【００５４】
図２において、例えば被写体等の物体側から、順次、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、絞りＦＡ、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１および光学フィルタＯＦの順で配列されており、各種の光学フィルタリング機能を有する光学フィルタＯＦの背後に結像される。
第１レンズＥ１は、物体側に凸に形成された負メニスカスレンズ、第２レンズＥ２は、物体側に凸に形成された正メニスカスレンズ、そして第３レンズＥ３は、物体側に凸に形成された正メニスカスレンズであり、第１レンズＥ１と第２レンズＥ２は、密に接合された２枚接合レンズであって、これら第１レンズＥ１〜第３レンズＥ３により構成する第１群光学系Ｇ１は、全体として正の焦点距離を呈する。
【００５５】
第４レンズＥ４は、物体側に凸に形成された負メニスカスレンズ、第５レンズＥ５は、両凹レンズからなる負レンズ、そして第６レンズＥ６は、両凸レンズからなる正レンズであり、第５レンズＥ５と第６レンズＥ６は、密に接合された２枚接合レンズであって、これら第４レンズＥ４〜第６レンズＥ６により構成する第２群光学系Ｇ２は、全体として負の焦点距離を呈する。第７レンズＥ７は、両凸レンズからなる正レンズ、第８レンズＥ８は、 両凹レンズからなる負レンズ、第９レンズＥ９は、両凸レンズからなる正レンズ、第１０レンズＥ１０は、両凹レンズからなる負レンズ、そして第１１レンズＥ１１は、両凸レンズからなる正レンズであり、第８レンズＥ８〜第１０レンズＥ１０は、密に接合された３枚接合レンズであって、これら第７レンズＥ７〜第１１レンズＥ１１により構成する第３群光学系Ｇ３は、全体として正の焦点距離を呈する。第２群光学系Ｇ２と第３群光学系Ｇ３との間に配置された絞りＦＡは、第３群光学系Ｇ３と一体的に動作し、第３群光学系Ｇ３との間の距離は一定である。第３群光学系Ｇ３の第１１レンズＥ１１の像面側に配置された光学フィルタＯＦは、ＣＣＤ撮像素子等の固体撮像素子５３のカバーガラスを含んでいてもよく、各種の光学フィルタリング機能を有する。
【００５６】
この第２の実施例では、第１群光学系Ｇ１の最も像面側に位置する第３レンズＥ３の像面側の面である第５面、第３群光学系Ｇ３の最も物体側に位置する第７レンズＥ７の物体側の面である第１２面および第３群光学系Ｇ３の最も像面側に位置する第１１レンズＥ１１の物体側の面である第１８面をそれぞれ非球面としている。
広角端、つまり短焦点距離端、と望遠端、つまり長焦点距離端、との間での変倍に伴う各群光学系Ｇ１〜Ｇ３の移動は、図２に示されるように、第１群光学系Ｇ１が、短焦点距離端から中間焦点距離への移動に伴って物体側から像面側へ向かって移動し、且つ中間焦点距離から長焦点距離端への移動に伴って像面側から物体側に向かって移動するとともに、短焦点距離端から長焦点距離端への移動に伴って、第２群光学系Ｇ２は、物体側から像面側へ向かって移動し、第３群光学系Ｇ３は像面側から物体側へ向かって移動する。
この第２の実施例においては、全系の焦点距離ｆ、ＦナンバＦ、そして半画角ωは、ズーミングにより、それぞれｆ＝５．０８１〜１５．３０７，Ｆ＝２．８７〜３．５３，ω＝４２．５〜１６．９の範囲で変化する。各光学面および光学素子に関連する光学特性は、次表の通りである。
【００５７】
【表５】
〈光学特性〉

表５における第５面、第１２面および第１８面の各光学面が非球面であり、各非球面における先に述べた式（４）に係るパラメータは、次表の通りである。
【００５８】
【表６】
〈非球面係数〉

【００５９】
第１群光学系Ｇ１と第２群光学系Ｇ２との間の間隔ｄ１、第２群光学系Ｇ２と絞りＦＡとの間の間隔ｄ２、そして第３群光学系Ｇ３と光学フィルタＯＦとの間の間隔ｄ３は、可変であり、これら可変間隔ｄ１、ｄ２およびｄ３は、ズーミングに伴って、全系の焦点距離ｆに対応して次表のように変化させられる。
【００６０】
【表７】
〈可変間隔〉

【００６１】
また、この第２の実施例における先に述べた本発明の各条件式（１）〜（３）に係るパラメータの値は、次表の通りとなり、各条件式の範囲内である。
【００６２】
【表８】
〈条件式のパラメータ値〉

【００６３】
この第２の実施例における収差図を図９に示している。
【００６４】
〔第３の実施例〕
図３は、本発明の第３の実施例に係るズームレンズの光学系の構成を示している。
図３に示すズームレンズは、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、絞りＦＡおよび光学フィルタ（カバーガラスを含む）ＯＦを具備している。この場合、第１レンズＥ１および第２レンズＥ２は、第１群光学系Ｇ１を構成し、第３レンズＥ３〜第５レンズＥ５は、第２群光学系Ｇ２を構成し、第６レンズＥ６〜第１０レンズＥ１０は、第３群光学系Ｇ３を構成しており、それぞれ各レンズ群毎に適宜なる共通の支持枠等によって支持され、ズーミング等に際しては各レンズ群毎に一体的に動作する。また、絞りＦＡは、第３群光学系Ｇ３の物体側に配置されており、第３群光学系Ｇ３と一体的に動作する。図３には、なお、図３に対する各参照符号は、参照符号の桁数の増大による説明の煩雑化を避けるため、各実施例毎に独立に用いており、そのため共通の参照符号を付していても他の実施例とかならずしも共通の構成ではない。
【００６５】
図３において、例えば被写体等の物体側から、順次、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、絞りＦＡ、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０および光学フィルタＯＦの順で配列されており、各種の光学フィルタリング機能を有する光学フィルタＯＦの背後に結像される。
第１レンズＥ１は、物体側に凸に形成された負メニスカスレンズ、そして第２レンズＥ２は、物体側に凸に形成された正メニスカスレンズであって、これら第１レンズＥ１および第２レンズＥ２により構成する第１群光学系Ｇ１は、全体として正の焦点距離を呈する。第３レンズＥ３は、物体側に凸に形成された負メニスカスレンズ、第４レンズＥ４は、両凹レンズからなる負レンズ、そして第５レンズＥ５は、物体側に凸に形成された正メニスカスレンズであり、第４レンズＥ４と第５レンズＥ５は、密に接合された２枚接合レンズであって、これら第３レンズＥ３〜第５レンズＥ５により構成する第２群光学系Ｇ２は、全体として負の焦点距離を呈する。
【００６６】
第６レンズＥ６は、両凸レンズからなる正レンズ、第７レンズＥ７は、 物体側に凸に形成された負メニスカスレンズ、第８レンズＥ８は、両凸レンズからなる正レンズ、第９レンズＥ９は、両凹レンズからなる負レンズ、そして第１０レンズＥ１０は、両凸レンズからなる正レンズであり、第７レンズＥ７〜第９レンズＥ９は、密に接合された３枚接合レンズであって、これら第６レンズＥ６〜第１０レンズＥ１０により構成する第３群光学系Ｇ３は、全体として正の焦点距離を呈する。第２群光学系Ｇ２と第３群光学系Ｇ３との間に配置された絞りＦＡは、第３群光学系Ｇ３と一体的に動作し、第３群光学系Ｇ３との間の距離は一定である。第３群光学系Ｇ３の第１０レンズＥ１０の像面側に配置された光学フィルタＯＦは、ＣＣＤ撮像素子等の固体撮像素子５３のカバーガラスを含んでいてもよく、各種の光学フィルタリング機能を有する。この第３の実施例では、第２群光学系Ｇ２の最も物体側に位置する第３レンズＥ３の物体側の面である第５面および第３群光学系Ｇ３の最も物体側に位置する第６レンズＥ６の物体側の面である第１１面をそれぞれ非球面としている。
【００６７】
広角端、つまり短焦点距離端、と望遠端、つまり長焦点距離端、との間での変倍に伴う各群光学系Ｇ１〜Ｇ３の移動は、図３に示されるように、第１群光学系Ｇ１が、短焦点距離端から中間焦点距離への移動に伴って物体側から像面側へ向かって移動し、且つ中間焦点距離から長焦点距離端への移動に伴って像面側から物体側に向かって移動するとともに、短焦点距離端から長焦点距離端への移動に伴って、第２群光学系Ｇ２は、物体側から像面側へ向かって移動し、第３群光学系Ｇ３は像面側から物体側へ向かって移動する。
この第３の実施例においては、全系の焦点距離ｆ、ＦナンバＦ、そして半画角ωは、ズーミングにより、それぞれｆ＝５．８９９〜２３．６１１，Ｆ＝３．１４〜３．８３，ω＝３６．７〜１０．６の範囲で変化する。各光学面および光学素子に関連する光学特性は、次表の通りである。
【００６８】
【表９】
〈光学特性〉

【００６９】
表９における第５面および第１１面の各光学面が非球面であり、各非球面における先に述べた式（４）に係るパラメータは、次表の通りである。
【００７０】
【表１０】
〈非球面係数〉

【００７１】
第１群光学系Ｇ１と第２群光学系Ｇ２との間の間隔ｄ１、第２群光学系Ｇ２と絞りＦＡとの間の間隔ｄ２、そして第３群光学系Ｇ３と光学フィルタＯＦとの間の間隔ｄ３は、可変であり、これら可変間隔ｄ１、ｄ２およびｄ３は、ズーミングに伴って、全系の焦点距離ｆに対応して次表のように変化させられる。
【００７２】
【表１１】
〈可変間隔〉

【００７３】
また、この第３の実施例における先に述べた本発明の各条件式（１）〜（３）に係るパラメータの値は、次表の通りとなり、各条件式の範囲内である。
【００７４】
【表１２】
〈条件式のパラメータ値〉

【００７５】
この第３の実施例における収差図を図１０に示している。
【００７６】
〔第４の実施例〕
図４は、本発明の第４の実施例に係るズームレンズの光学系の構成を示している。
図４に示すズームレンズは、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１、絞りＦＡおよび光学フィルタ（カバーガラスを含む）ＯＦを具備している。この場合、第１レンズＥ１〜第３レンズＥ３は、第１群光学系Ｇ１を構成し、第４レンズＥ４〜第６レンズＥ６は、第２群光学系Ｇ２を構成し、第７レンズＥ７〜第１１レンズＥ１１は、第３群光学系Ｇ３を構成しており、それぞれ各レンズ群毎に適宜なる共通の支持枠等によって支持され、ズーミング等に際しては各レンズ群毎に一体的に動作する。また、絞りＦＡは、第３群光学系Ｇ３の物体側に配置されており、第３群光学系Ｇ３と一体的に動作する。なお、図４に対する各参照符号は、参照符号の桁数の増大による説明の煩雑化を避けるため、各実施例毎に独立に用いており、そのため共通の参照符号を付していても他の実施例とかならずしも共通の構成ではない。
【００７７】
図４において、例えば被写体等の物体側から、順次、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、絞りＦＡ、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１および光学フィルタＯＦの順で配列されており、各種の光学フィルタリング機能を有する光学フィルタＯＦの背後に結像される。
第１レンズＥ１は、物体側に凸に形成された負メニスカスレンズ、第２レンズＥ２は、物体側に凸に形成された正メニスカスレンズ、そして第３レンズＥ３は、物体側に凸に形成された正メニスカスレンズであり、第１レンズＥ１と第２レンズＥ２は、密に接合された２枚接合レンズであって、これら第１レンズＥ１〜第３レンズＥ３により構成する第１群光学系Ｇ１は、全体として正の焦点距離を呈する。第４レンズＥ４は、物体側に凸に形成された負メニスカスレンズ、第５レンズＥ５は、両凹レンズからなる負レンズ、そして第６レンズＥ６は、両凸レンズからなる正レンズであり、第５レンズＥ５と第６レンズＥ６は、密に接合された２枚接合レンズであって、これら第４レンズＥ４〜第６レンズＥ６により構成する第２群光学系Ｇ２は、全体として負の焦点距離を呈する。
【００７８】
第７レンズＥ７は、物体側に凸に形成された正メニスカスレンズ、第８レンズＥ８は、 物体側に凸に形成された負メニスカスレンズ、第９レンズＥ９は、両凸レンズからなる正レンズ、第１０レンズＥ１０は、両凹レンズからなる負レンズ、そして第１１レンズＥ１１は、両凸レンズからなる正レンズであり、第８レンズＥ８〜第１０レンズＥ１０は、密に接合された３枚接合レンズであって、これら第７レンズＥ７〜第１１レンズＥ１１により構成する第３群光学系Ｇ３は、全体として正の焦点距離を呈する。第２群光学系Ｇ２と第３群光学系Ｇ３との間に配置された絞りＦＡは、第３群光学系Ｇ３と一体的に動作し、第３群光学系Ｇ３との間の距離は一定である。第３群光学系Ｇ３の第１１レンズＥ１１の像面側に配置された光学フィルタＯＦは、ＣＣＤ撮像素子等の固体撮像素子５３のカバーガラスを含んでいてもよく、各種の光学フィルタリング機能を有する。この第４の実施例では、第１群光学系Ｇ１の最も像面側に位置する第３レンズＥ３の物体側の面である第４面、第２群光学系Ｇ３の最も物体側に位置する第４レンズＥ４の物体側の面である第６面および第３群光学系Ｇ３の最も像面側に位置する第１１レンズＥ１１の物体側の面である第１８面をそれぞれ非球面としている。
【００７９】
広角端、つまり短焦点距離端、と望遠端、つまり長焦点距離端、との間での変倍に伴う各群光学系Ｇ１〜Ｇ３の移動は、図４に示されるように、第１群光学系Ｇ１が、短焦点距離端から中間焦点距離への移動に伴って物体側から像面側へ向かって移動し、且つ中間焦点距離から長焦点距離端への移動に伴って像面側から物体側に向かって移動するとともに、短焦点距離端から長焦点距離端への移動に伴って、第２群光学系Ｇ２は、物体側から像面側へ向かって移動し、第３群光学系Ｇ３は像面側から物体側へ向かって移動する。
この第４の実施例においては、全系の焦点距離ｆ、ＦナンバＦ、そして半画角ωは、ズーミングにより、それぞれｆ＝５．９００〜２３．６００，Ｆ＝３．０４〜３．７２，ω＝３８．２〜１１．１の範囲で変化する。各光学面および光学素子に関連する光学特性は、次表の通りである。
【００８０】
【表１３】
〈光学特性〉

【００８１】
表１３における第４面、第６面および第１８面の各光学面が非球面であり、各非球面における先に述べた式（４）に係るパラメータは、次表の通りである。
【００８２】
【表１４】
〈非球面係数〉

【００８３】
第１群光学系Ｇ１と第２群光学系Ｇ２との間の間隔ｄ１、第２群光学系Ｇ２と絞りＦＡとの間の間隔ｄ２、そして第３群光学系Ｇ３と光学フィルタＯＦとの間の間隔ｄ３は、可変であり、これら可変間隔ｄ１、ｄ２およびｄ３は、ズーミングに伴って、全系の焦点距離ｆに対応して次表のように変化させられる。
【００８４】
【表１５】
〈可変間隔〉

【００８５】
また、この第４の実施例における先に述べた本発明の各条件式（１）〜（３）に係るパラメータの値は、次表の通りとなり、各条件式の範囲内である。
【００８６】
【表１６】
〈条件式のパラメータ値〉

【００８７】
この第４の実施例における収差図を図１１に示している。
【００８８】
〔第５の実施例〕
図５は、本発明の第５の実施例に係るズームレンズの光学系の構成を示している。
図５に示すズームレンズは、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１、絞りＦＡおよび光学フィルタ（カバーガラスを含む）ＯＦを具備している。この場合、第１レンズＥ１〜第３レンズＥ３は、第１群光学系Ｇ１を構成し、第４レンズＥ４〜第６レンズＥ６は、第２群光学系Ｇ２を構成し、第７レンズＥ７〜第１１レンズＥ１１は、第３群光学系Ｇ３を構成しており、それぞれ各レンズ群毎に適宜なる共通の支持枠等によって支持され、ズーミング等に際しては各レンズ群毎に一体的に動作する。また、絞りＦＡは、第３群光学系Ｇ３の物体側に配置されており、第３群光学系Ｇ３と一体的に動作する。なお、図５に対する各参照符号は、参照符号の桁数の増大による説明の煩雑化を避けるため、各実施例毎に独立に用いており、そのため共通の参照符号を付していても他の実施例とかならずしも共通の構成ではない。
【００８９】
図５において、例えば被写体等の物体側から、順次、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、絞りＦＡ、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１および光学フィルタＯＦの順で配列されており、各種の光学フィルタリング機能を有する光学フィルタＯＦの背後に結像される。
第１レンズＥ１は、物体側に凸に形成された負メニスカスレンズ、第２レンズＥ２は、物体側に凸に形成された正メニスカスレンズ、そして第３レンズＥ３は、物体側に凸に形成された正メニスカスレンズであり、第１レンズＥ１と第２レンズＥ２は、密に接合された２枚接合レンズであって、これら第１レンズＥ１〜第３レンズＥ３により構成する第１群光学系Ｇ１は、全体として正の焦点距離を呈する。第４レンズＥ４は、物体側に凸に形成された負メニスカスレンズ、第５レンズＥ５は、両凹レンズからなる負レンズ、そして第６レンズＥ６は、両凸レンズからなる正レンズであり、第５レンズＥ５と第６レンズＥ６は、密に接合された２枚接合レンズであって、これら第４レンズＥ４〜第６レンズＥ６により構成する第２群光学系Ｇ２は、全体として負の焦点距離を呈する。
【００９０】
第７レンズＥ７は、両凸レンズからなる正レンズ、第８レンズＥ８は、物体側に凸に形成された負メニスカスレンズ、第９レンズＥ９は、両凸レンズからなる正レンズ、第１０レンズＥ１０は、両凹レンズからなる負レンズ、そして第１１レンズＥ１１は、両凸レンズからなる正レンズであり、第８レンズＥ８〜第１０レンズＥ１０は、密に接合された３枚接合レンズであって、これら第７レンズＥ７〜第１１レンズＥ１１により構成する第３群光学系Ｇ３は、全体として正の焦点距離を呈する。第２群光学系Ｇ２と第３群光学系Ｇ３との間に配置された絞りＦＡは、第３群光学系Ｇ３と一体的に動作し、第３群光学系Ｇ３との間の距離は一定である。第３群光学系Ｇ３の第１１レンズＥ１１の像面側に配置された光学フィルタＯＦは、ＣＣＤ撮像素子等の固体撮像素子５３のカバーガラスを含んでいてもよく、各種の光学フィルタリング機能を有する。この第５の実施例では、第１群光学系Ｇ１の最も像面側に位置する第３レンズＥ３の像面側の面である第５面、第３群光学系Ｇ３の最も物体側に位置する第７レンズＥ７の物体側の面である第１２面および第３群光学系Ｇ３の最も像面側に位置する第１１レンズＥ１１の物体側の面である第１８面をそれぞれ非球面としている。
【００９１】
広角端、つまり短焦点距離端、と望遠端、つまり長焦点距離端、との間での変倍に伴う各群光学系Ｇ１〜Ｇ３の移動は、図５に示されるように、第１群光学系Ｇ１が、短焦点距離端から中間焦点距離への移動に伴って物体側から像面側へ向かって移動し、且つ中間焦点距離から長焦点距離端への移動に伴って像面側から物体側に向かって移動するとともに、第２群光学系Ｇ２は、短焦点距離端から長焦点距離端への移動に伴って、物体側から像面側へ向かって移動し、第３群光学系Ｇ３は、短焦点距離端から中間焦点距離への移動に伴って像面側から物体側へ向かって移動し、且つ中間焦点距離から長焦点距離端への移動に伴って物体側から像面側へ向かって移動する。
この第５の実施例においては、全系の焦点距離ｆ、ＦナンバＦ、そして半画角ωは、ズーミングにより、それぞれｆ＝５．９００〜２３．６０１，Ｆ＝２．７９〜３．４１，ω＝３８．２〜１１．１の範囲で変化する。各光学面および光学素子に関連する光学特性は、次表の通りである。
【００９２】
【表１７】
〈光学特性〉

【００９３】
表１７における第５面、第１２面および第１８面の各光学面が非球面であり、各非球面における先に述べた式（４）に係るパラメータは、次表の通りである。
【００９４】
【表１８】
〈非球面係数〉

【００９５】
第１群光学系Ｇ１と第２群光学系Ｇ２との間の間隔ｄ１、第２群光学系Ｇ２と絞りＦＡとの間の間隔ｄ２、そして第３群光学系Ｇ３と光学フィルタＯＦとの間の間隔ｄ３は、可変であり、これら可変間隔ｄ１、ｄ２およびｄ３は、ズーミングに伴って、全系の焦点距離ｆに対応して次表のように変化させられる。
【００９６】
【表１９】
〈可変間隔〉

【００９７】
また、この第５の実施例における先に述べた本発明の各条件式（１）〜（３）に係るパラメータの値は、次表の通りとなり、各条件式の範囲内である。
【００９８】
【表２０】
〈条件式のパラメータ値〉

【００９９】
この第５の実施例における収差図を図１２に示している。
【０１００】
〔第６の実施例〕
図６は、本発明の第６の実施例に係るズームレンズの光学系の構成を示している。
図６に示すズームレンズは、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１、絞りＦＡおよび光学フィルタ（カバーガラスを含む）ＯＦを具備している。この場合、第１レンズＥ１〜第３レンズＥ３は、第１群光学系Ｇ１を構成し、第４レンズＥ４〜第６レンズＥ６は、第２群光学系Ｇ２を構成し、第７レンズＥ７〜第１１レンズＥ１１は、第３群光学系Ｇ３を構成しており、それぞれ各レンズ群毎に適宜なる共通の支持枠等によって支持され、ズーミング等に際しては各レンズ群毎に一体的に動作する。また、絞りＦＡは、第３群光学系Ｇ３の物体側に配置されており、第３群光学系Ｇ３と一体的に動作する。
なお、図６に対する各参照符号は、参照符号の桁数の増大による説明の煩雑化を避けるため、各実施例毎に独立に用いており、そのため共通の参照符号を付していても他の実施例とかならずしも共通の構成ではない。
【０１０１】
図６において、例えば被写体等の物体側から、順次、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、絞りＦＡ、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１および光学フィルタＯＦの順で配列されており、各種の光学フィルタリング機能を有する光学フィルタＯＦの背後に結像される。
第１レンズＥ１は、物体側に凸に形成された負メニスカスレンズ、第２レンズＥ２は、物体側に凸に形成された正メニスカスレンズ、そして第３レンズＥ３は、物体側に凸に形成された正メニスカスレンズであり、第１レンズＥ１と第２レンズＥ２は、密に接合された２枚接合レンズであって、これら第１レンズＥ１〜第３レンズＥ３により構成する第１群光学系Ｇ１は、全体として正の焦点距離を呈する。第４レンズＥ４は、物体側に凸に形成された負メニスカスレンズ、第５レンズＥ５は、両凹レンズからなる負レンズ、そして第６レンズＥ６は、物体側に凸に形成された正メニスカスレンズであり、第５レンズＥ５と第６レンズＥ６は、密に接合された２枚接合レンズであって、これら第４レンズＥ４〜第６レンズＥ６により構成する第２群光学系Ｇ２は、全体として負の焦点距離を呈する。
【０１０２】
第７レンズＥ７は、両凸レンズからなる正レンズ、第８レンズＥ８は、 両凹レンズからなる負レンズ、第９レンズＥ９は、両凸レンズからなる正レンズ、第１０レンズＥ１０は、両凹レンズからなる負レンズ、そして第１１レンズＥ１１は、物体側に凸に形成された正メニスカスレンズであり、第８レンズＥ８〜第１０レンズＥ１０は、密に接合された３枚接合レンズであって、これら第７レンズＥ７〜第１１レンズＥ１１により構成する第３群光学系Ｇ３は、全体として正の焦点距離を呈する。第２群光学系Ｇ２と第３群光学系Ｇ３との間に配置された絞りＦＡは、第３群光学系Ｇ３と一体的に動作し、第３群光学系Ｇ３との間の距離は一定である。第３群光学系Ｇ３の第１１レンズＥ１１の像面側に配置された光学フィルタＯＦは、ＣＣＤ撮像素子等の固体撮像素子５３のカバーガラスを含んでいてもよく、各種の光学フィルタリング機能を有する。この第６の実施例では、第２群光学系Ｇ２の最も物体側に位置する第４レンズＥ４の物体側の面である第６面、第３群光学系Ｇ３の最も物体側に位置する第７レンズＥ７の物体側の面である第１２面および第３群光学系Ｇ３の前記３枚接合レンズの最も像面側に位置する第１０レンズＥ１０の像面側の面である第１７面をそれぞれ非球面としている。
【０１０３】
広角端、つまり短焦点距離端、と望遠端、つまり長焦点距離端、との間での変倍に伴う各群光学系Ｇ１〜Ｇ３の移動は、図６に示されるように、短焦点距離端から長焦点距離端への移動に伴って、第１群光学系Ｇ１が、像面側から物体側に向かって移動し、第２群光学系Ｇ２は、物体側から像面側へ向かって移動し、そして第３群光学系Ｇ３は像面側から物体側へ向かって移動する。
この第６の実施例においては、全系の焦点距離ｆ、ＦナンバＦ、そして半画角ωは、ズーミングにより、それぞれｆ＝５．９００〜３５．４０４，Ｆ＝３．６０〜３．８８，ω＝３８．２〜７．５の範囲で変化する。各光学面および光学素子に関連する光学特性は、次表の通りである。
【０１０４】
【表２１】
〈光学特性〉

【０１０５】
表２１における第６面、第１２面および第１７面の各光学面が非球面であり、各非球面における先に述べた式（４）に係るパラメータは、次表の通りである。
【０１０６】
【表２２】
〈非球面係数〉

【０１０７】
第１群光学系Ｇ１と第２群光学系Ｇ２との間の間隔ｄ１、第２群光学系Ｇ２と絞りＦＡとの間の間隔ｄ２、そして第３群光学系Ｇ３と光学フィルタＯＦとの間の間隔ｄ３は、可変であり、これら可変間隔ｄ１、ｄ２およびｄ３は、ズーミングに伴って、全系の焦点距離ｆに対応して次表のように変化させられる。
【０１０８】
【表２３】
〈可変間隔〉

【０１０９】
また、この第６の実施例における先に述べた本発明の各条件式（１）〜（３）に係るパラメータの値は、次表の通りとなり、各条件式の範囲内である。
【０１１０】
【表２４】
〈条件式のパラメータ値〉

この第６の実施例における収差図を図１３に示している。
【０１１１】
〔第７の実施例〕
図７は、本発明の第７の実施例に係るズームレンズの光学系の構成を示している。
図７に示すズームレンズは、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１、絞りＦＡおよび光学フィルタ（カバーガラスを含む）ＯＦを具備している。この場合、第１レンズＥ１〜第３レンズＥ３は、第１群光学系Ｇ１を構成し、第４レンズＥ４〜第６レンズＥ６は、第２群光学系Ｇ２を構成し、第７レンズＥ７〜第１１レンズＥ１１は、第３群光学系Ｇ３を構成しており、それぞれ各レンズ群毎に適宜なる共通の支持枠等によって支持され、ズーミング等に際しては各レンズ群毎に一体的に動作する。また、絞りＦＡは、第３群光学系Ｇ３の物体側に配置されており、第３群光学系Ｇ３と一体的に動作する。なお、図７に対する各参照符号は、参照符号の桁数の増大による説明の煩雑化を避けるため、各実施例毎に独立に用いており、そのため共通の参照符号を付していても他の実施例とかならずしも共通の構成ではない。
【０１１２】
図７において、例えば被写体等の物体側から、順次、第１レンズＥ１、第２レンズＥ２、第３レンズＥ３、第４レンズＥ４、第５レンズＥ５、第６レンズＥ６、絞りＦＡ、第７レンズＥ７、第８レンズＥ８、第９レンズＥ９、第１０レンズＥ１０、第１１レンズＥ１１および光学フィルタＯＦの順で配列されており、各種の光学フィルタリング機能を有する光学フィルタＯＦの背後に結像される。
第１レンズＥ１は、物体側に凸に形成された負メニスカスレンズ、第２レンズＥ２は、物体側に凸に形成された正メニスカスレンズ、そして第３レンズＥ３は、物体側に凸に形成された正メニスカスレンズであり、第１レンズＥ１と第２レンズＥ２は、密に接合された２枚接合レンズであって、これら第１レンズＥ１〜第３レンズＥ３により構成する第１群光学系Ｇ１は、全体として正の焦点距離を呈する。第４レンズＥ４は、物体側に凸に形成された負メニスカスレンズ、第５レンズＥ５は、両凹レンズからなる負レンズ、そして第６レンズＥ６は、両凸レンズからなる正レンズであり、第５レンズＥ５と第６レンズＥ６は、密に接合された２枚接合レンズであって、これら第４レンズＥ４〜第６レンズＥ６により構成する第２群光学系Ｇ２は、全体として負の焦点距離を呈する。
【０１１３】
第７レンズＥ７は、両凸レンズからなる正レンズ、第８レンズＥ８は、物体側に凸に形成された負メニスカスレンズ、第９レンズＥ９は、両凸レンズからなる正レンズ、第１０レンズＥ１０は、両凹レンズからなる負レンズ、そして第１１レンズＥ１１は、両凸レンズからなる正レンズであり、第８レンズＥ８〜第１０レンズＥ１０は、密に接合された３枚接合レンズであって、これら第７レンズＥ７〜第１１レンズＥ１１により構成する第３群光学系Ｇ３は、全体として正の焦点距離を呈する。第２群光学系Ｇ２と第３群光学系Ｇ３との間に配置された絞りＦＡは、第３群光学系Ｇ３と一体的に動作し、第３群光学系Ｇ３との間の距離は一定である。第３群光学系Ｇ３の第１１レンズＥ１１の像面側に配置された光学フィルタＯＦは、ＣＣＤ撮像素子等の固体撮像素子５３のカバーガラスを含んでいてもよく、各種の光学フィルタリング機能を有する。この第７の実施例では、第２群光学系Ｇ２の最も物体側に位置する第４レンズＥ４の物体側の面である第６面、第３群光学系Ｇ３の最も物体側に位置する第７レンズＥ７の物体側の面である第１２面および第３群光学系Ｇ３の最も像面側に位置する第１１レンズＥ１１の物体側の面である第１８面をそれぞれ非球面としている。
【０１１４】
広角端、つまり短焦点距離端、と望遠端、つまり長焦点距離端、との間での変倍に伴う各群光学系Ｇ１〜Ｇ３の移動は、図７に示されるように、短焦点距離端から長焦点距離端への移動に伴って、第１群光学系Ｇ１が、像面側から物体側に向かって移動し、第２群光学系Ｇ２は、物体側から像面側へ向かって移動し、そして第３群光学系Ｇ３は像面側から物体側へ向かって移動する。
この第７の実施例においては、全系の焦点距離ｆ、ＦナンバＦ、そして半画角ωは、ズーミングにより、それぞれｆ＝５．８９８〜２３．６０５，Ｆ＝２．７９〜３．４５，ω＝３８．３〜１１．１の範囲で変化する。各光学面および光学素子に関連する光学特性は、次表の通りである。
【０１１５】
【表２５】
〈光学特性〉

【０１１６】
表２５における第６面、第１２面および第１８面の各光学面が非球面であり、各非球面における先に述べた式（４）に係るパラメータは、次表の通りである。
【０１１７】
【表２６】
〈非球面係数〉

【０１１８】
第１群光学系Ｇ１と第２群光学系Ｇ２との間の間隔ｄ１、第２群光学系Ｇ２と絞りＦＡとの間の間隔ｄ２、そして第３群光学系Ｇ３と光学フィルタＯＦとの間の間隔ｄ３は、可変であり、これら可変間隔ｄ１、ｄ２およびｄ３は、ズーミングに伴って、全系の焦点距離ｆに対応して次表のように変化させられる。
【０１１９】
【表２７】
〈可変間隔〉

【０１２０】
また、この第７の実施例における先に述べた本発明の各条件式（１）〜（３）に係るパラメータの値は、次表の通りとなり、各条件式の範囲内である。
【０１２１】
【表２８】
〈条件式のパラメータ値〉

この第７の実施例における収差図を図１４に示している。
【０１２２】
上述した第６の実施例は、長焦点距離端の開口絞りを短焦点端に対して大きくして、長焦点距離端のＦナンバを小さくした場合の実施例である。
また、上述した各レンズには第２群光学系Ｇ２と第３群光学系Ｇ３の間に長焦点距離端以外の変倍領域において、中間画角の光束の一部を遮光するための絞りを配置することが可能である。そこで、上述した第６の実施の形態にこの遮光のための絞りを設けた場合の収差図の例を図１５に示す。この場合の遮光のための絞りの位置は、次の通りである。
短焦点距離端： 第２群光学系Ｇ２から像面側に１０mmの位置
中間焦点距離： 第２群光学系Ｇ２から像面側に１mmの位置
この例では、短焦点距離端から中間焦点距離までの中間像高の光束の一部を遮光するため、遮光のための絞り位置および絞り径を変化させた例を示しているが、収差の状況に応じ、位置および径を固定して、遮光する変倍域は例えば短焦点距離端のみなどとしても良いことはいうまでもない。
【０１２３】
上述した各実施例から明らかなように、本発明に係るズームレンズは、レンズの構成枚数が１０〜１１枚と少なく、非常にコンパクトなレンズであるため省資源化に対応でき、且つ短焦点距離側の半画角が３８°以上と広画角で、変倍比が約３倍〜６倍と高変倍比でありながら、ズーム域全体にわたって、３００万画素以上の撮像素子にも対応可能となるように、色収差を初め緒収差を良好に補正することができる。さらに全てのレンズ材質として、化学的に安定で鉛や砒素等の有害物質を含まない光学ガラスを使用しているため、材料のリサイクル化が可能で、加工時の廃液による水質汚染のおそれが無く、地球環境保全が可能となる。また、上記各実施例のズームレンズを撮影用レンズとしてカメラに使用することで、カメラとして高性能を維持しながら、大幅な小型化、軽量化および低コスト化を実現し且つ省電力を達成することが可能となる。
このようなカメラ機能に、さらに、通信機能を付加させて携帯情報端末装置を構成することによって、携帯情報端末装置の大幅な小型化、軽量化および低コスト化を実現し、且つ省電力を達成することが可能となる。
【０１２４】
【発明の効果】
以上述べたように、本発明によれば、３倍を超える高変倍比でありながら、短焦点距離端の半画角が３８°以上と広画角で、ズーム全域にわたってその上３００万画素以上の高密度の撮像素子に対応可能な高解像力の結像性能を有し、レンズ全長およびレンズ外径が非常に小さく、レンズの構成枚数も１０枚程度と少なくすることができて省資源化に対応することが可能で、しかも全てのレンズを化学的に安定で且つ鉛や砒素等の有害物質を含まない光学ガラスで構成することができて、材料のリサイクル化をも可能とし、加工時の廃液による水質汚染等のおそれもない地球環境を考慮したズームレンズ、並びにそのズームレンズを用いる撮像装置および携帯情報端末装置を提供することができる。
【０１２５】
すなわち本発明の請求項１のズームレンズによれば、正の屈折力を有する第１群光学系と、負の屈折力を有する第２群光学系と、正の屈折力を有する第３群光学系とを、物体側から像面側に向かって順次配置するとともに、前記第３群光学系の物体側に前記第３群光学系と一体的に移動する絞りを有し、短焦点距離端と長焦点距離端との間での変倍に伴って、短焦点距離端にて前記第１群光学系と前記第２群光学系との間隔が最小となり、長焦点距離端にて前記第２群光学系と前記第３群光学系との間隔が最小となるよう、少なくとも前記第１群光学系と前記第３群光学系とを移動させるズームレンズにおいて、
前記第３群光学系が、
物体側から順に、１枚の正レンズ、負レンズと正レンズと負レンズとを順次配置して接合してなる３枚接合レンズ、 1 枚の正レンズから構成され、
前記第３群光学系の前記３枚接合レンズのうちの正レンズの屈折率をＮｐ、前記第３群光学系の前記３枚接合レンズのうちの２枚の負レンズの屈折率の平均をＮｎ、前記第３群光学系の前記３枚接合レンズのうちの正レンズのアッベ数をνｐ、そして前記第３群光学系の前記３枚接合レンズのうちの２枚の負レンズのアッベ数の平均をνｎとすると、条件式：
−０．２２＜Ｎｐ−Ｎｎ＜０ （２）
３＜νｐ−νｎ＜３６ （３）
を満足することにより、３倍を超える高変倍比でありながら、短焦点距離端の半画角が３８°以上と広画角で、その上３００万画素以上の高密度の撮像素子に対応可能な高解像力の結像性能を実現し、レンズ全長およびレンズ外径を非常に小さくし、レンズの構成枚数も１０枚程度と少なくすることができて省資源化に対応することが可能で、しかも全てのレンズを化学的に安定で且つ鉛や砒素等の有害物質を含まない光学ガラスで構成することができて、材料のリサイクル化をも可能とし、加工時の廃液による水質汚染等のおそれもなく、特に、広画角化に伴って発生する倍率の色収差補正に大きな効果を得ることができ、
特に、前記条件式（２）および条件式（３）を満足することにより、低コストで、他の収差とのバランスを良好に保ちつつ良好な色収差補正を実現することが可能となり、さらに、前記第３群光学系が、前記３枚接合レンズの物体側および像面側に少なくとも１枚の正レンズをさらに有することにより、特に、第３群光学系を正、負、正、負、正の構成として屈折力をバランス良く配置し各レンズ面における収差の発生を抑え、且つ偏心等の製造誤差による性能劣化も小さく抑えることが可能となる。
【０１２６】
また、本発明の請求項２のズームレンズによれば、請求項１のズームレンズにおいて、前記第１群光学系が、短焦点距離端と長焦点距離端との間での中間焦点距離状態を経ての変倍動作に伴って像面側に凸形状をなして移動することにより、特に、第２群光学系の移動により、主に変倍を行ない、且つその他の群の移動により、変倍および変倍に伴う像面位置の変動の補正を行なって、良好なレンズ性能を得ることが可能となる。
本発明の請求項３のズームレンズによれば、請求項２のズームレンズにおいて、前記第１群光学系が、短焦点距離端および長焦点距離端以外の中間焦点距離において、最も像面に近い位置へ移動することにより、特に、第１群光学系が、変倍に伴う像面位置変動の補正を行なって、良好なレンズ性能を得ることが可能となる。
【０１２７】
本発明の請求項４のズームレンズによれば、請求項１〜請求項３のうちのいずれか１項のズームレンズにおいて、前記第３群光学系の前記３枚接合レンズの最も物体側の負レンズが、像面側に強い凹面を向けて形成されることにより、特に、比較的簡単な構成で、不要な収差の発生を抑え、且つ主に球面収差およびコマ収差を効果的に補正することが可能となる。
本発明の請求項５のズームレンズによれば、請求項１〜請求項４のうちのいずれか１項のズームレンズにおいて、前記条件式（１）を満足することにより、特に、小型化を実現して、しかも各群光学系における収差の発生および偏心等の製造誤差による性能劣化を効果的に抑制することが可能となる。
【０１２８】
本発明の請求項６のズームレンズによれば、請求項１〜請求項５のうちいずれか１項のズームレンズにおいて、前記３枚接合レンズの物体側および像面側に配置された正レンズのうちの少なくとも１枚の正レンズが、非球面を有することにより、特に、軸上と軸外の光束が分離した位置に配置でき、主に非点収差補正が効果的に行える。
本発明の請求項７のズームレンズによれば、請求項１〜請求項６のうちのいずれか１項のズームレンズにおいて、収差補正に最低限必要な正レンズと負レンズを前記第１群光学系および前記第２群光学系の各々に加えることにより、ズームレンズ全体の構成の簡略化、小型化、低コスト化を図りつつ、各収差を小さく抑える正レンズと負レンズを少なくとも１枚ずつ含むことにより、特に、適切に収差補正を行なってしかも小型化を達成することが可能となる。
【０１２９】
また、本発明の請求項８の撮像装置によれば、撮影用光学系として、請求項１〜請求項７のうちのいずれか１項のズームレンズを使用することにより、３倍を超える高変倍比でありながら、短焦点距離端の半画角が３８°以上と広画角で、その上３００万画素以上の高密度の撮像素子に対応可能な高解像力の結像性能を実現し、レンズ全長およびレンズ外径を非常に小さくし、レンズの構成枚数も１０枚程度と少なくすることができて省資源化に対応することが可能で、しかも全てのレンズを化学的に安定で且つ鉛や砒素等の有害物質を含まない光学ガラスで構成することができて、材料のリサイクル化をも可能とし、加工時の廃液による水質汚染等のおそれもなく、特に、コンパクトで、高変倍、高画質および省電力な撮像装置を提供することができる。
本発明の請求項９の撮像装置によれば、請求項８の撮像装置において、当該撮像装置が、撮影画像をディジタル情報とする機能を含むディジタルカメラとすることにより、特に、非常にコンパクトで、高変倍および高画質を実現することが可能となり、プリンタにより本発明に係るディジタルカメラで記録した被写体像を出力しても、従来の銀鉛カメラでの画質と比べ同程度以上の品質の出力、即ち画質を得ることができる。
【０１３０】
また、本発明の請求項１０の携帯情報端末装置によれば、カメラ機能部の撮影用光学系として、請求項１〜請求項７のうちのいずれか１項のズームレンズを使用することにより、３倍を超える高変倍比でありながら、短焦点距離端の半画角が３８°以上と広画角で、その上３００万画素以上の高密度の撮像素子に対応可能な高解像力の結像性能を実現し、レンズ全長およびレンズ外径を非常に小さくし、レンズの構成枚数も１０枚程度と少なくすることができて省資源化に対応することが可能で、しかも全てのレンズを化学的に安定で且つ鉛や砒素等の有害物質を含まない光学ガラスで構成することができて、材料のリサイクル化をも可能とし、加工時の廃液による水質汚染等のおそれもなく、特に、非常に小型で、しかも高品質な記録データを得ることが可能な携帯情報端末装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係るズームレンズの第１の実施例の光学系構成を示す構成図である。
【図２】本発明の第１の実施の形態に係るズームレンズの第２の実施例の光学系構成を示す構成図である。
【図３】本発明の第１の実施の形態に係るズームレンズの第３の実施例の光学系構成を示す構成図である。
【図４】本発明の第１の実施の形態に係るズームレンズの第４の実施例の光学系構成を示す構成図である。
【図５】本発明の第１の実施の形態に係るズームレンズの第５の実施例の光学系構成を示す構成図である。
【図６】本発明の第１の実施の形態に係るズームレンズの第６の実施例の光学系構成を示す構成図である。
【図７】本発明の第１の実施の形態に係るズームレンズの第７の実施例の光学系構成を示す構成図である。
【図８】図１のズームレンズにおける収差特性を示す収差図である。
【図９】図２のズームレンズにおける収差特性を示す収差図である。
【図１０】図３のズームレンズにおける収差特性を示す収差図である。
【図１１】図４のズームレンズにおける収差特性を示す収差図である。
【図１２】図５のズームレンズにおける収差特性を示す収差図である。
【図１３】図６のズームレンズにおける収差特性を示す収差図である。
【図１４】図７のズームレンズにおける収差特性を示す収差図である。
【図１５】図６のズームレンズにおける短焦点距離端および中間焦点距離における中間像高の光束を絞りによって遮光したときの収差特性を示す収差図である。
【図１６】本発明の第２の実施の形態に係るレンジファインダタイプの光学ファインダを備えたディジタルカメラの構成を概念的に示す概略構成図である。
【図１７】本発明の第３の実施の形態に係る一眼レフレックスタイプの光学ファインダを備えたディジタルカメラの構成を概念的に示す概略構成図である。
【図１８】本発明の第２および第３の実施の形態に係るディジタルカメラまたは携帯情報端末装置の制御構成を概略的に示すブロック図である。
【符号の説明】
Ｇ１ 第１群光学系
Ｇ２ 第２群光学系
Ｇ３ 第３群光学系
ＦＡ 絞り
ＯＦ 光学フィルタ
Ｅ１ 第１レンズ
Ｅ２ 第２レンズ
Ｅ３ 第３レンズ
Ｅ４ 第４レンズ
Ｅ５ 第５レンズ
Ｅ６ 第６レンズ
Ｅ７ 第７レンズ
Ｅ８ 第８レンズ
Ｅ９ 第９レンズ
Ｅ１０ 第１０レンズ
Ｅ１１ 第１１レンズ
１〜２１ 各面
ＦＡ 絞り
ＯＦ 光学フィルタ
５１ 撮像装置
５２ 撮影用ズーム光学系
５２ａ 撮影ズームレンズ
５２ｂ 機械的駆動機構
５３ 固体撮像素子
５４ 信号処理部
５５ Ａ／Ｄ（アナログ−ディジタル）変換部
５６ ディジタル信号処理部
５７ 画像メモリ
５８ 制御部
５９ モータドライバ
６０ タイミング制御回路
６１ データ記録部
６２ 表示装置
６３ ストロボ装置
６４ 通信用インタフェース（Ｉ／Ｆ）
７１，８１ ファインダ光学系
８２ 可動レフレックスミラー
８３ フォーカシングスクリーン
８４ ペンタプリズム
８５ 接眼レンズ[0001]
BACKGROUND OF THE INVENTION
  The present invention uses a compact zoom lens suitable for a video camera and a still video camera, and uses the zoom lens as a photographing optical system.Imaging deviceThe present invention also relates to a portable information terminal device using the zoom lens as a photographing optical system of a camera function unit.
[0002]
[Prior art]
In recent years, zoom lenses mounted on video cameras and still video cameras have become more demanding for higher zoom ratios, wider angles of view, and higher resolution, as well as smaller, lighter, and lower cost. In order to cope with this, it is essential to shorten the total lens length and the outer diameter of the lens and to reduce the number of components.
As such a zoom lens, in order from the object side, a first group optical system having a positive refractive power, a second group optical system having a negative refractive power, and a third group optical system having a positive refractive power And the distance between the first group optical system and the second group optical system is increased with zooming from the short focal length end to the long focal length end, and the second group optical There has been proposed a zoom type configuration in which the zooming operation is performed by reducing the distance between the system and the third group optical system.
A zoom type that has a zoom ratio exceeding 3 times is proposed in the following Patent Document 1, Patent Document 2, and Patent Document 3.
[0003]
[Patent Document 1]
JP 2000-275526 A
[Patent Document 2]
JP 11-242157 A
[Patent Document 3]
Japanese Patent No. 2899019
Moreover, as what has achieved the high magnification close | similar to 10 times as a magnification ratio, there exist some which were described in the following patent document 4, for example.
[0004]
[Patent Document 4]
JP-A-11-109234
None of these configurations of Patent Documents 1 to 4 has a narrow half angle of view at the short focal length end of around 30 °, and cannot sufficiently meet the demand for wide angle of view.
Further, for example, the following Patent Document 5 discloses a configuration corresponding to a comparatively wide angle of view with a half angle of view at the short focal length end of around 37 °.
[0005]
[Patent Document 5]
Japanese Patent Laid-Open No. 11-6958
However, in the configuration disclosed in Patent Document 5 and the like, the F value (F number) is F4.1 at the short focal length end and F5.8 at the long focal length end, and the lens becomes dark. In such a dark lens, if the size of one pixel is reduced as the density of an imaging device such as a CCD (charge coupled device) imaging device is increased, the performance is greatly deteriorated in a high frequency region. It is not possible to fully meet the demands for conversion.
In addition, for example, Japanese Patent Application Laid-Open No. H10-228707 describes a field of view corresponding to a wide field angle of 45 ° or more at the short focal length end.
[0006]
[Patent Document 6]
JP 2002-072088 A
However, in the configuration shown in Patent Document 6, the zoom ratio is 2 times or less, and it cannot sufficiently meet the demand for high zoom ratio.
[0007]
[Problems to be solved by the invention]
  The present invention has been made in view of the above-described circumstances, and has a wide field angle of 38 ° or more at the short focal length end, while having a high zoom ratio exceeding 3 times, and 3 million pixels. With high resolution imaging performance compatible with the above high-density imaging devices, the total lens length and lens outer diameter are very small, and the number of lenses can be reduced to about 10 to save resources. In addition, all lenses can be made of optically stable glass that is chemically stable and free of harmful substances such as lead and arsenic. It is an object of the present invention to provide a zoom lens in consideration of the global environment that is free from the risk of water pollution due to the waste liquid, an imaging device and a portable information terminal device using the zoom lens.
The object of claim 1 of the present invention is particularly effective in correcting chromatic aberrations of on-axis and off-axis magnifications that occur with a wide angle of view.Can perform good chromatic aberration correctionIt is to provide a zoom lens.
[0008]
The object of claim 2 of the present invention is to perform zooming mainly by moving the second group optical system, and to change the image plane position accompanying zooming and zooming by moving other groups. It is an object of the present invention to provide a zoom lens capable of obtaining good lens performance by performing the above correction.
An object of claim 3 of the present invention is to provide a zoom lens in which, in particular, the first group optical system can correct image plane position fluctuation accompanying zooming to obtain good lens performance. It is in.
An object of the present invention is to provide a zoom lens that can suppress unnecessary aberrations and can effectively correct mainly spherical aberration and coma aberration, with a relatively simple configuration. .
An object of claim 5 of the present invention is to provide a zoom lens that can achieve downsizing and effectively suppress performance deterioration due to production errors such as aberration and decentering in each group optical system. It is in.
[0009]
  BookClaims of the invention6In particular, an object of the present invention is to provide a zoom lens capable of effectively shortening the overall length of the third group optical system.
  Claims of the invention7In particular, it is an object of the present invention to provide a zoom lens capable of appropriately performing aberration correction and achieving miniaturization.
  Further claims of the present invention8In particular, an object of the present invention is to provide an image pickup apparatus that is compact and can realize high zoom ratio, high image quality, and power saving.
  Claims of the invention9In particular, an object of the present invention is to provide an imaging apparatus that is very compact and can realize high zoom ratio and high image quality.
Further, the claims of the present invention10In particular, an object of the present invention is to provide a portable information terminal device that is capable of obtaining extremely small and high-quality recorded data.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, a zoom lens according to the present invention described in claim 1 is provided.
  A first group optical system having a positive refractive power, a second group optical system having a negative refractive power, and a third group optical system having a positive refractive power are sequentially applied from the object side to the image plane side. And a stop that moves integrally with the third group optical system on the object side of the third group optical system, and is accompanied by zooming between the short focal length end and the long focal length end. The distance between the first group optical system and the second group optical system is minimized at the short focal length end, and the distance between the second group optical system and the third group optical system at the long focal length end. In a zoom lens that moves at least the first group optical system and the third group optical system so as to be minimized,
  The third group optical system is
In order from the object side, one positive lens,Negative lensAnd positivelensAnd negativeThree-piece cemented lens formed by sequentially arranging and cementing lenses, 1 Consists of one positive lens,
The refractive index of the positive lens of the three-piece cemented lens of the third group optical system is Np, and the average refractive index of the two negative lenses of the three-piece cemented lens of the third group optical system is Nn. Νp is the positive Abbe number of the three cemented lenses of the third group optical system, and the average is the Abbe number of the two negative lenses of the three cemented lenses of the third group optical system. Is a conditional expression:
  −0.22 <Np−Nn <0 (2)
    3 <νp−νn <36 (3)
  Satisfy
  It is characterized by that.
  The zoom lens according to the second aspect of the present invention is the zoom lens according to the first aspect, wherein the first group optical system is in an intermediate focal length state between a short focal length end and a long focal length end. And moving in a convex shape toward the image plane side in accordance with the zooming operation after passing through.
[0011]
A zoom lens according to a third aspect of the present invention is the zoom lens according to the second aspect, wherein the first group optical system has the most image plane at an intermediate focal length other than the short focal length end and the long focal length end. It is characterized by moving to a close position.
The zoom lens according to a fourth aspect of the present invention is the zoom lens according to any one of the first to third aspects, wherein the third lens group optical system has the most object side of the three-piece cemented lens. The negative lens is formed with a strong concave surface facing the image surface side.
A zoom lens according to a fifth aspect of the present invention is the zoom lens according to any one of the first to fourth aspects, wherein the first group optical system and the second group optical in the entire zoom range. If the amount of change in the group interval with the system is K12, the combined focal length of the entire system at the short focal length end is fw, and the combined focal length of the entire system at the long focal length end is ft, the conditional expression:
0.6 <K12 / (fw + ft) <1.2 (1)
It is characterized by satisfying.
[0013]
  Claim6The zoom lens according to the present invention described in claim 1Any one of 1-5In the zoom lens, at least one positive lens among positive lenses arranged on the object side and the image plane side of the three-piece cemented lens has an aspherical surface.
  Claim7The zoom lens according to the present invention described in claim 1 is described in claim 1.6In the zoom lens according to any one of the above, each of the first group optical system and the second group optical system includes at least one positive lens and one negative lens.
  Claim8In order to achieve the above-mentioned object, the imaging apparatus according to the present invention described in 1 is used as an imaging optical system.7The zoom lens according to any one of the above is used.
  Claim9An imaging device according to the present invention described in claim8In this imaging apparatus, the imaging apparatus is a digital camera including a function of using a captured image as digital information.
  Claim10In order to achieve the above-described object, the portable information terminal device according to the present invention described in 1 is used as a photographing optical system of a camera function unit.7The zoom lens according to any one of the above is used.
[0014]
[Action]
  That is, the zoom lens according to claim 1 of the present invention includes a first group optical system having a positive refractive power, a second group optical system having a negative refractive power, and a third group optical system having a positive refractive power. Are arranged sequentially from the object side to the image plane side, and have a stop that moves integrally with the third group optical system on the object side of the third group optical system. Along with the focal length end, the distance between the first group optical system and the second group optical system is minimized at the short focal length end, and the second group at the long focal length end. In a zoom lens that moves at least the first group optical system and the third group optical system so that the distance between the optical system and the third group optical system is minimized,
  The third group optical system is
In order from the object side, one positive lens,Negative lensAnd positivelensAnd negativeThree-piece cemented lens formed by sequentially arranging and cementing lenses, 1 Consists of one positive lens,
The refractive index of the positive lens of the three-piece cemented lens of the third group optical system is Np, and the average refractive index of the two negative lenses of the three-piece cemented lens of the third group optical system is Nn. Νp is the positive Abbe number of the three cemented lenses of the third group optical system, and the average is the Abbe number of the two negative lenses of the three cemented lenses of the third group optical system. Is a conditional expression:
  −0.22 <Np−Nn <0 (2)
    3 <νp−νn <36 (3)
  Satisfy.
[0015]
  The configuration of the conventional third-group optical system includes three lenses having positive, negative, and positive refractive power, four lenses having positive, positive, negative, and positive refractive power, and the like as necessary. In the present invention, the third group optical system includes a negative, positive, and negative three-lens cemented lens, so that cemented surfaces at different positions from the stop are arranged. It is possible to correct chromatic aberration on the axis and off-axis to some extent by utilizing the fact that the way of the on-axis and off-axis rays on the two joint surfaces is different. This effect is particularly remarkable for correcting chromatic aberration of magnification that occurs with a wide angle of view.
Further, since the three-lens cemented lens can suppress the optical axis shift between the two cemented surfaces, the chromatic aberration of magnification is corrected well when compared with the two-group cemented lens. Yes.
  In addition, the third group optical system further includes at least one positive lens on the object side and the image plane side of the three-piece cemented lens, in particular, the third group optical system is positive, negative, positive, negative, As a positive configuration, the refractive powers are arranged in a well-balanced manner to suppress the occurrence of aberration on each lens surface, and it is possible to suppress performance degradation due to manufacturing errors such as decentration.
  In addition, by satisfying the conditional expressions (2) and (3), it is possible to achieve good chromatic aberration correction while maintaining a good balance with other aberrations, particularly at low cost.
[0016]
With the above-described configuration, while having a high zoom ratio exceeding 3 times, the half field angle at the short focal length end is a wide field angle of 38 ° or more, and in addition, a high-density image sensor with 3 million pixels or more. Realizing imaging performance with high resolution that can be handled, the total lens length and lens outer diameter are very small, and the number of lenses can be reduced to about 10 to save resources. In addition, all lenses can be made of optically stable glass that is chemically stable and does not contain harmful substances such as lead and arsenic, and can be recycled. There is no fear, and in particular, a great effect can be obtained in correcting chromatic aberration of magnification that occurs with a wide angle of view.
The zoom lens according to a second aspect of the present invention is the zoom lens according to the first aspect, wherein the first group optical system passes through an intermediate focal length state between a short focal length end and a long focal length end. It moves in a convex shape on the image plane side with the zooming operation.
With such a configuration, in particular, zooming is performed mainly by movement of the second group optical system, and correction of image plane position variation due to zooming and zooming is performed by movement of other groups, Good lens performance can be obtained.
[0017]
A zoom lens according to a third aspect of the present invention is the zoom lens according to the second aspect, wherein the first group optical system is closest to the image plane at an intermediate focal length other than the short focal length end and the long focal length end. Moving.
With such a configuration, in particular, the first group optical system can correct image plane position fluctuation accompanying zooming and obtain good lens performance.
A zoom lens according to a fourth aspect of the present invention is the zoom lens according to any one of the first to third aspects, wherein the most object-side negative lens of the three-piece cemented lens of the third group optical system is The concave surface is formed with a strong concave surface facing the image surface side.
In this way, the refractive power of the object side surface of the negative lens closest to the object side is made as weak as possible, the generation of unnecessary aberrations is suppressed with a relatively simple configuration, and mainly spherical aberration and coma with a strong refractive power on the image side. It becomes possible to correct aberrations effectively.
[0018]
  The zoom lens according to a fifth aspect of the present invention satisfies the conditional expression (1) in the zoom lens according to any one of the first to fourth aspects.
  With such a configuration, it is particularly possible to achieve downsizing and to effectively suppress performance deterioration due to manufacturing errors such as occurrence of aberration and decentration in each group optical system..
[0019]
  Claims of the invention6The zoom lens according to claimAny one of claims 1 to 5.In the zoom lens, at least one positive lens among the positive lenses disposed on the object side and the image plane side of the three-piece cemented lens has an aspherical surface.
  With such a configuration, it is possible to effectively shorten the overall length of the third group optical system, and it is effective mainly for correcting spherical aberration, coma aberration, and astigmatism.
  Claims of the invention7The zoom lens according to claim 1.6In the zoom lens according to any one of the above, each of the first group optical system and the second group optical system includes at least one positive lens and one negative lens.
  With such a configuration, it is particularly possible to perform aberration correction appropriately and achieve size reduction and cost reduction.
  Further, the claims of the present invention8The imaging apparatus according to claim 1 is an optical system for photographing.7The zoom lens according to any one of the above is used.
[0020]
  With such a configuration, it has a wide zoom ratio of 38 ° or more at the short focal length end and a high-magnification ratio of more than 3 times, and also supports high-density image sensors with more than 3 million pixels. Realizing imaging performance with high resolving power, making the total lens length and lens outer diameter very small, the number of lenses can be reduced to about 10 and corresponding to resource saving. In addition, all lenses can be made of optical glass that is chemically stable and does not contain toxic substances such as lead and arsenic, making it possible to recycle materials and possibly causing water pollution due to waste liquid during processing. In particular, it is possible to provide an imaging apparatus that is compact and can achieve high zooming, high image quality, and power saving.
  Claims of the invention9An imaging device according to claim8In this imaging apparatus, the imaging apparatus is a digital camera including a function of using a captured image as digital information.
[0021]
  With such a configuration, in particular, a digital camera that is very compact, can achieve high zoom ratio and high image quality, and can obtain a printed photograph with the same or better quality as an image obtained by a conventional silver-lead camera. An imaging apparatus such as
  Further, the claims of the present invention10The portable information terminal device according to claim 1 is a photographing optical system of a camera function unit.7The zoom lens according to any one of the above is used.
  With such a configuration, it has a wide zoom ratio of 38 ° or more at the short focal length end and a high-magnification ratio of more than 3 times, and also supports high-density image sensors with more than 3 million pixels. Realizing imaging performance with high resolving power, making the total lens length and lens outer diameter very small, the number of lenses can be reduced to about 10 and corresponding to resource saving. In addition, all lenses can be made of optical glass that is chemically stable and does not contain toxic substances such as lead and arsenic, making it possible to recycle materials and possibly causing water pollution due to waste liquid during processing. In particular, it is possible to provide a portable information terminal device that is extremely small and capable of obtaining high-quality recorded data.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, based on the embodiment of the present invention and examples showing specific numerical examples, the zoom lens of the present invention with reference to the drawings,Imaging deviceThe portable information terminal device will be described in detail. The first embodiment of the present invention is an embodiment of a zoom lens according to the present invention, and the second and third embodiments of the present invention are as shown in the first embodiment. According to the present invention, the zoom lens is used as an imaging optical system.As an imaging device1 is an embodiment of a portable information terminal device according to the present invention using a camera or a zoom lens as shown in the first embodiment as a photographing optical system of a camera function unit.
  First, the basic configuration of the zoom lens according to the first embodiment of the present invention will be described. The specific configuration of the zoom lens according to the first embodiment of the present invention will be described as specific numerical examples later as first to seventh examples, and FIGS. This will be described in detail with reference to the optical system configuration diagram and the aberration diagrams shown in FIGS.
[0023]
  The zoom lens according to the first embodiment of the present invention includes a first group optical system having a positive refractive power, a second group optical system having a negative refractive power, and a third group optical having a positive refractive power. Are arranged sequentially from the object side to the image plane side, the distance between the first group optical system and the second group optical system is minimized at the short focal length end, and the long focal length end At least the first group optical system and the third group optical system are moved so that the distance between the second group optical system and the third group optical system is minimized. A zoom lens comprising a three-piece cemented lens comprising a lens, a positive lens, and a negative lensTheThe configuration of the third group optical system in the conventional zoom lens of this type includes three lenses having positive, negative, and positive refractive power, four lenses having positive, positive, negative, and positive refractive power, and the like. A configuration is used in which two of them are joined as necessary.
[0024]
In the present invention, the third group optical system includes a negative, positive, and negative three cemented lens, so that two cemented surfaces at different positions from the stop are arranged, and the axes of the two cemented surfaces are arranged. By utilizing the fact that the upper and off-axis rays pass differently, the on-axis and off-axis chromatic aberration correction can be individually corrected to some extent. This is particularly effective in correcting chromatic aberration of magnification that occurs with a wide angle of view. As a method of obtaining two cemented surfaces, it is possible to arrange two pairs of cemented lenses. However, when the optical axis misalignment of the two groups of cemented lenses occurs due to the assembly decentering, lateral chromatic aberration occurs asymmetrically. And unnatural color blur occurs. In the case of a three-piece cemented lens, the optical axis deviation between the two cemented surfaces can be kept small, so that it is possible to satisfactorily correct the chromatic aberration of magnification even compared to the two pairs of cemented lenses.
Specifically, for example, as in the first embodiment shown in FIG. 1, the second group optical system G2 is fixed with respect to the image plane, and the first group optical system G1 is short-focused. While moving from the distance end (Wide) toward the long focal length end (Tele) toward the object side, the third group optical system G3 moves toward the object side from the short focal length end toward the long focal length end.
[0025]
As another example, as in the second to fourth embodiments shown in FIGS. 2 to 4, the first group optical system G1 is directed toward the image plane side from the short focal length end to the intermediate focal length (Mean). The second group optical system G2 moves toward the object side from the short focal length end to the long focal length end, and moves to the object side from the intermediate focal length toward the long focal length end. The optical system G3 moves toward the object side from the short focal length end to the long focal length end.
In the case of the fifth embodiment shown in FIG. 5, the movement of the first group optical system G1 and the second group optical system G2 is the same as that in FIGS. 2 to 4, but the third group optical system G3. Moves toward the object side from the short focal length end to the intermediate focal length, and moves toward the image plane side from the intermediate focal length to the long focal length end.
As yet another example, as in the sixth and seventh embodiments shown in FIGS. 6 and 7, the first group optical system G1 moves toward the object side from the short focal length end to the long focal length end. At the same time, the second group optical system G2 moves toward the image plane side from the short focal length end to the long focal length end, and the third group optical system G3 moves toward the object side from the short focal length end to the long focal length end. Moving.
[0026]
  In such a zoom lens, the first group optical system G1 draws a locus having a convex shape on the image plane side in any of the first to seventh embodiments shown in FIGS. It is characterized by movingTheThe second group optical system G2 moves along a locus that is substantially monotonic or slightly convex toward the image surface side, and the third group optical system G3 moves along a locus that is substantially monotonic or slightly convex toward the object side. To do. By moving each group in this way, the zooming is mainly performed by moving the second group optical system G2, and the other groups change the image plane position due to zooming and zooming depending on the way of movement. Make corrections.
  Further, as in the second to fourth embodiments shown in FIGS. 2 to 4, the first group optical system G <b> 1 has a short focal length end in order to correct the image plane position variation accompanying the zooming. You may move to a position closest to the image plane at a focal length other than the long focal length end.Yes.
[0027]
  Then, the most object side negative lens among the negative-positive-negative three-piece cemented lenses arranged in the third group optical system G3 may be arranged with the strong concave surface facing the image plane side.Yes.The object side surface of the most object side negative lens is made as weak as possible to suppress the occurrence of unnecessary aberrations, and mainly the spherical aberration and the coma aberration are corrected by the image side surface.
  Desirably, the change amount of the group interval between the first group optical system G1 and the second group optical system G2 in the entire zoom range is K12, the combined focal length of the entire system at the short focal length end is fw, and the long focal length Conditional expression (1) is satisfied when the combined focal length of the entire end system is ft.The
[0028]
    0.6 <K12 / (fw + ft) <1.2 (1)
  This conditional expression (1) prescribes the amount of change in the distance between the first group optical system G1 and the second group optical system G2 mainly for zooming, and {K12 / (fw + ft)} is the upper limit. If the value exceeds the upper limit, the fluctuations of the first group optical system G1 and the second group optical system G2 increase, and the zoom lens itself increases in size and the front lens diameter increases, making it impossible to achieve downsizing. On the other hand, if {K12 / (fw + ft)} is less than the lower limit, the power of the first group optical system G1 and the second group optical system G2 becomes too strong, and the amount of aberration generated in each group increases, and the decentration etc. Deterioration of performance due to manufacturing errors of the above increases, and good imaging performance cannot be obtained.
  Further preferably, the refractive index of the positive lens of the negative-positive-negative three-piece cemented lens described above of the third group optical system G3 is Np, and the two negative lenses of the three-piece cemented lens of the third group optical system G3 are used. Is the average refractive index of Nn, the Abbe number of the positive lens of the third cemented lens of the third group optical system G3 is νp, and the Abbe number of the two negative lenses of the third cemented lens of the third group optical system G3. When the average is νn, conditional expressions (2) and (3) should be satisfiedThe
[0029]
-0.22 <Np-Nn <0 (2)
3 <νp−νn <36 (3)
Conditional expression (2) and conditional expression (3) give conditions for good chromatic aberration correction, and {Np−Nn} is less than the lower limit of conditional expression (2) or {νp− If νn exceeds the upper limit of conditional expression (3), good chromatic aberration correction capability can be obtained, but the glass material of the positive lens becomes very expensive. Conversely, when {Np−Nn} exceeds the upper limit of conditional expression (2) or {νp−νn} becomes less than the lower limit of conditional expression (3), the balance between axial chromatic aberration and other aberrations is balanced. It becomes difficult to keep it good, and axial chromatic aberration at the end of the long focal length increases, and the ability to correct chromatic aberration at the joint surface on the object side is significantly reduced.
[0030]
  Further, at least one positive lens may be further provided on each of the object side and the image plane side of the three-piece cemented lens of the third group optical system G3.Yes.Since the three-piece cemented lens has two strong concave surfaces, it is necessary to arrange a positive refractive power to counter these negative refractive powers. By arranging positive lenses on the object side and the image plane side of the three-piece cemented lens, the third group optical system G3 has a positive, negative, positive, negative, and positive configuration, and the refractive power is arranged in a balanced manner. Therefore, the occurrence of aberration on one lens surface can be effectively suppressed, and performance degradation due to manufacturing errors such as decentration can be suppressed to a small level.
Further, it is desirable that at least one of the at least one positive lens disposed on the object side and the image plane side of the three-piece cemented lens has an aspherical surface.Yes.By forming an aspherical surface on at least one surface of the positive lens disposed on the object side and the image plane side of the three-piece cemented lens of the third group optical system G3, the total length of the third group optical system G3 can be shortened. It becomes possible. When an aspherical surface is provided on the lens on the object side, the aspherical surface is disposed at a position close to the stop, so that it is mainly effective for correcting spherical aberration and coma aberration. In addition, when an aspherical surface is provided on the positive lens on the image side, the aspherical surface is disposed at a position away from the stop, so that it can be disposed at a position where the on-axis and off-axis light beams are separated, Mainly effective in correcting astigmatism.
[0031]
  It is further desirable that the first group optical system G1 and the second group optical system G2 have at least one positive lens and one negative lens.Yes.In order to obtain a high-performance zoom lens, it is necessary to keep each aberration small. In order to correct each aberration satisfactorily, it is necessary to increase the number of lenses to some extent and to suppress the occurrence of aberration in each lens. However, when the number of lenses is increased, each group becomes thick, and it becomes impossible to reduce the size of the entire zoom lens, and the mechanism becomes complicated, which causes an increase in manufacturing costs. Therefore, in the zoom lens according to the present invention, the first group optical system G1 and the second group optical system G2 are configured to have at least one positive lens and at least one negative lens necessary for aberration correction. Specifically, the first group optical system G1 has three negative, positive, and positive configurations, or two negative and positive configurations, and the second group optical system G2 has three negative, negative, and positive configurations. The configuration. In order to maintain good imaging performance with such a small number of lenses, it is desirable to provide at least one aspheric surface in the first group optical system G1 or the second group optical system G2.
[0032]
  AboveTazuThe camera can be configured using a zoom lens as a zoom lens for photographing, which is the second and third embodiments of the present invention.TheAn imaging apparatus according to the second embodiment of the present invention records an image of a subject through the zoom lens according to the present invention described above, and uses a so-called silver salt camera that uses a film as a recording medium. It is applied to a so-called digital camera or digital video that forms an image on a light-receiving image sensor using a CCD or the like and records information on the subject as digital information.AndTherefore, it is possible to obtain an imaging device that is very compact, can achieve high zoom ratio and high image quality, and can save power. Furthermore, it is desirable that the light receiving image sensor for receiving an image of a subject by such a zoom lens has 3 million pixels or more. As the number of pixels increases, the light receiving image sensor can improve the recording density of the subject image. By having more than 3 million pixels, the subject image recorded by the imaging apparatus of the present invention is output by a printer. In addition, it is possible to obtain an output image having a quality equivalent to or higher than that of a conventional silver salt camera.
[0033]
  According to the second embodiment of the present invention using the zoom lens described above.As an imaging deviceA conceptual diagram of the digital camera is shown in FIG.
  The imaging device 51 captures a subject optically and forms a subject image, and a photographic zoom optical system 52 for photoelectrically converting the subject image formed by the photographic zoom optical system 52, for example, And a solid-state image sensor 53 such as a CCD image sensor. Further, a range finder type finder optical system 71 for visually recognizing the photographing range of the subject may be provided as necessary.
FIG. 17 shows a conceptual diagram of a digital camera according to the third embodiment of the present invention using the zoom lens described above. FIG. 17 shows a main configuration of a single-lens reflex (single-lens reflex) type digital camera.
[0034]
As in the case of FIG. 16, the imaging device 51 optically captures a subject and forms a subject image, and a photographic zoom optical system 52 and a subject image formed by the photographic zoom optical system 52. For example, a solid-state imaging device 53 such as a CCD imaging device. In this case, a single-lens reflex type finder optical system 81 is used to visually recognize the shooting range of the subject. That is, the finder optical system 81 is inserted into the subject image imaging optical path of the photographic zoom optical system 52 when the photographing range is visually confirmed, and reflects and deflects the optical path to guide the finder optical path. A movable reflex mirror 82 retracted from the object image forming optical path (82A), a focusing screen 83 for forming an object image when the photographing range is visually recognized, and a bent finder optical path for observing the imaging state of the focusing screen 83 A pentaprism 84 to be formed and an eyepiece 85 for observing the image of the focusing screen 83 guided by the pentaprism 84 as a real image are configured.
[0035]
The photographing zoom optical system 52 is configured using a zoom lens corresponding to any one of the examples according to the first embodiment described above, and a focal point (not shown) is provided at a predetermined position behind the zoom lens. A solid-state image sensor 53 is arranged through a shutter of a plain format or the like.
The configuration of an example of the control system of the image pickup apparatus 51 in the cameras according to the second and third embodiments is shown in FIG. The photographing zoom optical system 52 includes a photographing zoom lens 52a corresponding to any one of the examples according to the first embodiment described above and a mechanical drive mechanism 52b that mechanically drives the photographing zoom lens 52a. Made up of. The mechanical drive mechanism 52b includes, for example, an autofocus mechanism, a mechanical shutter mechanism, and a zoom mechanism that changes the zoom lens group interval.
[0036]
The image of the subject guided by the optical system is formed on the solid-state image sensor 53, color-separated by a filter (not shown) disposed on the solid-state image sensor 53, photoelectrically converted, and R ( Red (red), G (green), and B (blue) analog image signals are output. In the signal processing unit 54, the output analog signal is subjected to image signal noise reduction by a correlated double sampling circuit (CDS circuit), image signal level adjustment by an auto gain control circuit (AGC circuit), and the like. The signal that has passed through the signal processing unit 54 is converted into analog image data with optimum sampling frequency by an A / D (analog-digital) conversion unit 55.
The digitized image data is subjected to digital signal processing including image processing such as white balance adjustment for adjusting the gain of each of the R and G signals and processing for separating the digital image data into color difference and luminance in the digital signal processing unit 56. To do. The image data digitally processed by the digital signal processing unit 56 is temporarily stored in the image memory 57.
[0037]
The control unit 58 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU operates using the RAM as a work area according to a program stored in the ROM. By doing so, the entire system is controlled. For example, the motor driver 59 for driving the mechanical drive mechanism 52 b operates based on a control signal from the control unit 58 to drive the mechanical drive mechanism 52 b of the zoom optical system 52. The timing control circuit 60 controls the generation and signal processing of the drive control signal for the solid-state image sensor 53 and the A / D conversion timing in the A / D conversion unit 55.
When configured as a camera, for example, as shown in FIG. 18, in addition to the imaging device 51, for example, using a medium such as a flash memory card, a data recording unit 61 for recording a captured image is provided. Furthermore, a display device 62 for displaying the photographing range is provided by an LCD (liquid crystal display device) or the like as necessary.
[0038]
  In addition, a strobe device 63 can be further provided for photographing a dark subject. When a dark subject whose light quantity is insufficient is photographed, the strobe device 63 illuminates the subject appropriately. Shooting is possible.
According to the second and third embodiments, a portable information terminal device may be configured in which a functional configuration similar to that of the imaging device described above is incorporated as a camera function unit. That is, the zoom lens according to the first embodiment described above is used as the zoom optical system for photographing in the camera function unit in the portable information terminal device having the camera function unit, and is related to FIGS. A portable information terminal device is configured by incorporating the same configuration as the imaging device described above.The
  The portable information terminal device is a camera as shown in FIG.(Imaging device)In addition to the above configuration, the camera function unit is configured by including a communication interface (I / F) 64 for transmitting image data photographed and recorded by the camera to a personal computer PC or the like via a communication system, for example. .
  In such a portable information terminal device, by using the above-described camera as a built-in camera function unit, the portable information terminal device can be remarkably reduced in size and high-quality recorded data can be obtained.
[0039]
【Example】
Next, several examples showing specific numerical configurations of the zoom lens according to the first embodiment of the present invention described above will be described in detail.
Specific examples and numerical examples of the zoom lens according to the first embodiment of the present invention will be described. In each embodiment, the aberration of the zoom lens is sufficiently corrected, and it is possible to cope with a light receiving element having 3 to 5 million pixels. It is clear from each example that by configuring the zoom lens as in the first embodiment, a very good image performance can be secured while achieving a sufficiently small size and wide angle of view. I will.
In the description related to each of the following embodiments, the following various symbols are used.
[0040]
R: radius of curvature of each surface
D: Surface spacing
Nd: Refractive index for d-line
νd: Abbe number for d-line
f: Total focal length of the entire system
F: F number
ω: Half angle of view
y ′: Image height
Wide: Short focal length end
Mean: intermediate focal length
Tele: Long focal length end
In addition, the following symbols are used to define an aspheric surface.
[0041]
Y: Height from the optical axis
R: aspherical paraxial radius of curvature
K: Conical multiplier
A₄: 4th order aspheric coefficient
A₆: 6th-order aspheric coefficient
A₈: 8th-order aspheric coefficient
A₁₀: 10th-order aspheric coefficient
SQRT: square root
That is, the aspherical surface is expressed by the following equation as the distance X from the tangential plane at the aspherical vertex of the aspherical surface at the height Y from the optical axis.
[0042]
[Expression 1]

[0043]
In the numerical examples described below, E-XY is 10^-XYMeans. Further, in the aberration diagrams described below, in spherical aberration, a solid line represents spherical aberration, a broken line represents a sine condition, and astigmatism, a solid line represents a sagittal image plane and a broken line represents a meridional image plane. One solid line represents the d line (587.56 nm), and the other solid line represents the g line (435.83 nm).
[0044]
[First embodiment]
FIG. 1 shows the configuration of an optical system of a zoom lens according to the first embodiment of the present invention.
The zoom lens shown in FIG. 1 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, and a ninth lens. A lens E9, a tenth lens E10, an eleventh lens E11, an aperture FA and an optical filter (including a cover glass) OF are provided. In this case, the first lens E1 to the third lens E3 constitute the first group optical system G1, the fourth lens E4 to the sixth lens E6 constitute the second group optical system G2, and the seventh lens E7 to E7. The eleventh lens E11 constitutes the third group optical system G3, and is supported by a common support frame or the like that is appropriate for each lens group, and operates integrally for each lens group during zooming or the like.
The stop FA is disposed on the object side of the third group optical system G3 and operates integrally with the third group optical system G3. In FIG. 1, the surface number of each optical surface is also attached for reference. In addition, in order to avoid complication of explanation due to an increase in the number of digits of the reference code, each reference code for FIG. 1 is used independently for each embodiment. Therefore, even if a common reference code is attached, It is not necessarily the same configuration as the embodiment.
[0045]
In FIG. 1, for example, from the object side such as a subject, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an aperture FA, and a seventh lens are sequentially arranged. E7, eighth lens E8, ninth lens E9, tenth lens E10, eleventh lens E11, and optical filter OF are arranged in this order, and are imaged behind optical filter OF having various optical filtering functions. .
The first lens E1 is a negative meniscus lens that is convex on the object side, the second lens E2 is a positive meniscus lens that is convex on the object side, and the third lens E3 is convex on the object side. The first lens E1 and the second lens E2 are closely cemented two-lens cemented lenses, and a first group optical system G1 composed of the first lens E1 to the third lens E3. Exhibits a positive focal length as a whole.
[0046]
The fourth lens E4 is a negative meniscus lens that is convex on the object side, the fifth lens E5 is a negative lens that is a biconcave lens, and the sixth lens E6 is a positive meniscus lens that is convex on the object side. The fifth lens E5 and the sixth lens E6 are two cemented lenses that are closely joined, and the second group optical system G2 constituted by the fourth lens E4 to the sixth lens E6 is negative as a whole. Of focal length. The seventh lens E7 is a positive lens composed of a biconvex lens, the eighth lens E8 is a negative meniscus lens formed convex on the object side, the ninth lens E9 is a positive lens composed of a biconvex lens, and the tenth lens E10 is The negative lens composed of a biconcave lens, and the eleventh lens E11 are positive lenses composed of a biconvex lens, and the eighth lens E8 to the tenth lens E10 are closely cemented three-element cemented lenses. The third group optical system G3 configured by the lenses E7 to E11 exhibits a positive focal length as a whole. The stop FA disposed between the second group optical system G2 and the third group optical system G3 operates integrally with the third group optical system G3, and the distance from the third group optical system G3 is constant. It is.
[0047]
The optical filter OF disposed on the image plane side of the eleventh lens E11 of the third group optical system G3 may include a cover glass of the solid-state image sensor 53 such as a CCD image sensor, and has various optical filtering functions. . In the first embodiment, the sixth surface, which is the object side surface of the fourth lens E4 located closest to the object side of the second group optical system G2, and the first surface located closest to the object side of the third group optical system G3. The twelfth surface that is the object side surface of the seven lens E7 is an aspherical surface.
The movement of each of the group optical systems G1 to G3 accompanying the zooming between the wide-angle end, that is, the short focal length end, and the telephoto end, that is, the long focal length end, as shown in FIG. The optical system G2 is fixed with respect to the image plane without moving, and the first group optical system G1 moves from the image plane side to the object side in accordance with the movement from the short focal length end to the long focal length end. The third group optical system G3 also moves from the image plane side to the object side.
In this first embodiment, the focal length f, F number F, and half angle of view ω of the entire system are f = 5.902 to 17.707 and F = 3.37 to 4.41 by zooming, respectively. , Ω = 38.2 to 14.7. The optical characteristics associated with each optical surface and optical element are as shown in the following table. The lens surface marked with * is an aspherical surface.
[0048]
[Table 1]
<optical properties>

[0049]
The optical surfaces of the sixth surface and the twelfth surface in Table 1 are aspheric surfaces, and the parameters relating to the above-described equation (4) in each aspheric surface are as follows.
[0050]
[Table 2]
<Aspheric coefficient>

The distance d1 between the first group optical system G1 and the second group optical system G2, the distance d2 between the second group optical system G2 and the stop FA, and between the third group optical system G3 and the optical filter OF The distance d3 is variable, and the variable distances d1, d2 and d3 are changed as shown in the following table in accordance with the focal length f of the entire system with zooming.
[0051]
[Table 3]
<Variable interval>

The values of the parameters according to the conditional expressions (1) to (3) of the present invention described above in the first embodiment are as shown in the following table, and are within the range of the conditional expressions.
[0052]
[Table 4]
<Parameter value of conditional expression>

FIG. 8 shows aberration diagrams in the first example.
[0053]
[Second Embodiment]
FIG. 2 shows the configuration of the optical system of the zoom lens according to the second embodiment of the present invention.
The zoom lens shown in FIG. 2 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, and a ninth lens. A lens E9, a tenth lens E10, an eleventh lens E11, an aperture FA and an optical filter (including a cover glass) OF are provided. In this case, the first lens E1 to the third lens E3 constitute the first group optical system G1, the fourth lens E4 to the sixth lens E6 constitute the second group optical system G2, and the seventh lens E7 to E7. The eleventh lens E11 constitutes the third group optical system G3, and is supported by a common support frame or the like that is appropriate for each lens group, and operates integrally for each lens group during zooming or the like. The stop FA is disposed on the object side of the third group optical system G3 and operates integrally with the third group optical system G3. FIG. 2 also shows the surface numbers of the respective optical surfaces.
In addition, in order to avoid complication of explanation due to an increase in the number of digits of the reference code, each reference code for FIG. 2 is used independently for each embodiment. Therefore, even if a common reference code is attached, It is not necessarily the same configuration as the embodiment.
[0054]
In FIG. 2, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the aperture FA, and the seventh lens are sequentially arranged from the object side such as a subject. E7, eighth lens E8, ninth lens E9, tenth lens E10, eleventh lens E11, and optical filter OF are arranged in this order, and are imaged behind optical filter OF having various optical filtering functions. .
The first lens E1 is a negative meniscus lens that is convex on the object side, the second lens E2 is a positive meniscus lens that is convex on the object side, and the third lens E3 is convex on the object side. The first lens E1 and the second lens E2 are closely cemented two-lens cemented lenses, and a first group optical system G1 composed of the first lens E1 to the third lens E3. Exhibits a positive focal length as a whole.
[0055]
The fourth lens E4 is a negative meniscus lens convexly formed on the object side, the fifth lens E5 is a negative lens composed of a biconcave lens, and the sixth lens E6 is a positive lens composed of a biconvex lens. E5 and the sixth lens E6 are closely cemented two-piece cemented lenses, and the second group optical system G2 constituted by the fourth lens E4 to the sixth lens E6 exhibits a negative focal length as a whole. . The seventh lens E7 is a positive lens composed of a biconvex lens, the eighth lens E8 is a negative lens composed of a biconcave lens, the ninth lens E9 is a positive lens composed of a biconvex lens, and the tenth lens E10 is a negative lens composed of a biconcave lens. The lens and the eleventh lens E11 are positive lenses composed of biconvex lenses, and the eighth lens E8 to the tenth lens E10 are closely cemented three-lens cemented lenses, and the seventh lens E7 to eleventh. The third group optical system G3 configured by the lens E11 exhibits a positive focal length as a whole. The stop FA disposed between the second group optical system G2 and the third group optical system G3 operates integrally with the third group optical system G3, and the distance from the third group optical system G3 is constant. It is. The optical filter OF disposed on the image plane side of the eleventh lens E11 of the third group optical system G3 may include a cover glass of the solid-state image sensor 53 such as a CCD image sensor, and has various optical filtering functions. .
[0056]
In the second embodiment, the fifth surface, which is the image surface side surface of the third lens E3 located closest to the image plane of the first group optical system G1, is positioned closest to the object side of the third group optical system G3. The twelfth surface which is the object side surface of the seventh lens E7 and the eighteenth surface which is the object side surface of the eleventh lens E11 located closest to the image plane of the third group optical system G3 are aspherical surfaces. .
The movement of each of the group optical systems G1 to G3 accompanying the zooming between the wide-angle end, that is, the short focal length end, and the telephoto end, that is, the long focal length end, as shown in FIG. The optical system G1 moves from the object side to the image plane side with the movement from the short focal length end to the intermediate focal length, and from the image plane side with the movement from the intermediate focal length to the long focal length end. While moving toward the object side, the second group optical system G2 moves from the object side toward the image plane side with the movement from the short focal length end to the long focal length end, and the third group optical system G3 moves from the image plane side toward the object side.
In the second embodiment, the focal length f, F number F, and half angle of view ω of the entire system are f = 5.081 to 15.307 and F = 2.87 to 3.53 by zooming, respectively. , Ω = 42.5 to 16.9. The optical characteristics associated with each optical surface and optical element are as shown in the following table.
[0057]
[Table 5]
<optical properties>

The optical surfaces of the fifth surface, the twelfth surface, and the eighteenth surface in Table 5 are aspheric surfaces, and the parameters according to the above-described equation (4) in each aspheric surface are as shown in the following table.
[0058]
[Table 6]
<Aspheric coefficient>

[0059]
The distance d1 between the first group optical system G1 and the second group optical system G2, the distance d2 between the second group optical system G2 and the stop FA, and between the third group optical system G3 and the optical filter OF The distance d3 is variable, and the variable distances d1, d2 and d3 are changed as shown in the following table in accordance with the focal length f of the entire system with zooming.
[0060]
[Table 7]
<Variable interval>

[0061]
The values of the parameters according to the conditional expressions (1) to (3) of the present invention described above in the second embodiment are as shown in the following table, and are within the range of the conditional expressions.
[0062]
[Table 8]
<Parameter value of conditional expression>

[0063]
FIG. 9 shows aberration diagrams in the second example.
[0064]
[Third embodiment]
FIG. 3 shows the configuration of the optical system of a zoom lens according to the third embodiment of the present invention.
The zoom lens shown in FIG. 3 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, and a ninth lens. A lens E9, a tenth lens E10, an aperture FA, and an optical filter (including a cover glass) OF are provided. In this case, the first lens E1 and the second lens E2 constitute the first group optical system G1, the third lens E3 to the fifth lens E5 constitute the second group optical system G2, and the sixth lens E6 to E6. The tenth lens E10 constitutes the third group optical system G3, and is supported by a common support frame or the like appropriate for each lens group, and operates integrally for each lens group during zooming or the like. The stop FA is disposed on the object side of the third group optical system G3 and operates integrally with the third group optical system G3. In FIG. 3, the reference numerals for FIG. 3 are used independently for each embodiment in order to avoid complication of the explanation due to an increase in the number of digits of the reference numerals. However, it is not necessarily a common configuration with other embodiments.
[0065]
In FIG. 3, for example, in order from the object side such as a subject, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the aperture FA, the sixth lens E6, and the seventh lens. E7, the eighth lens E8, the ninth lens E9, the tenth lens E10, and the optical filter OF are arranged in this order, and an image is formed behind the optical filter OF having various optical filtering functions.
The first lens E1 is a negative meniscus lens that is convex on the object side, and the second lens E2 is a positive meniscus lens that is convex on the object side. The first lens E1 and the second lens E2 The first group optical system G1 configured by the above exhibits a positive focal length as a whole. The third lens E3 is a negative meniscus lens that is convex on the object side, the fourth lens E4 is a negative lens that is a biconcave lens, and the fifth lens E5 is a positive meniscus lens that is convex on the object side. The fourth lens E4 and the fifth lens E5 are closely cemented two-lens lenses, and the second group optical system G2 constituted by the third lens E3 to the fifth lens E5 is negative as a whole. Of focal length.
[0066]
The sixth lens E6 is a positive lens composed of a biconvex lens, the seventh lens E7 is a negative meniscus lens formed convex on the object side, the eighth lens E8 is a positive lens composed of a biconvex lens, and the ninth lens E9 is The negative lens composed of a biconcave lens and the tenth lens E10 are positive lenses composed of a biconvex lens, and the seventh lens E7 to the ninth lens E9 are closely cemented three-element cemented lenses. The third group optical system G3 configured by the lenses E6 to E10 exhibits a positive focal length as a whole. The stop FA disposed between the second group optical system G2 and the third group optical system G3 operates integrally with the third group optical system G3, and the distance from the third group optical system G3 is constant. It is. The optical filter OF disposed on the image plane side of the tenth lens E10 of the third group optical system G3 may include a cover glass of the solid-state image sensor 53 such as a CCD image sensor, and has various optical filtering functions. . In the third embodiment, the fifth surface, which is the object-side surface of the third lens E3 located closest to the object side of the second group optical system G2, and the third surface located closest to the object side of the third group optical system G3. The eleventh surface, which is the object side surface of the six lens E6, is an aspherical surface.
[0067]
The movement of each of the group optical systems G1 to G3 accompanying the zooming between the wide angle end, that is, the short focal length end, and the telephoto end, that is, the long focal length end, as shown in FIG. The optical system G1 moves from the object side to the image plane side with the movement from the short focal length end to the intermediate focal length, and from the image plane side with the movement from the intermediate focal length to the long focal length end. While moving toward the object side, the second group optical system G2 moves from the object side toward the image plane side with the movement from the short focal length end to the long focal length end, and the third group optical system G3 moves from the image plane side toward the object side.
In the third embodiment, the focal length f, F number F, and half angle of view ω of the entire system are f = 5.899 to 23.611, F = 3.14 to 3.83, respectively, by zooming. , Ω = 36.7 to 10.6. The optical characteristics associated with each optical surface and optical element are as shown in the following table.
[0068]
[Table 9]
<optical properties>

[0069]
The optical surfaces of the fifth surface and the eleventh surface in Table 9 are aspheric surfaces, and the parameters relating to the above-described equation (4) in each aspheric surface are as shown in the following table.
[0070]
[Table 10]
<Aspheric coefficient>

[0071]
The distance d1 between the first group optical system G1 and the second group optical system G2, the distance d2 between the second group optical system G2 and the stop FA, and between the third group optical system G3 and the optical filter OF The distance d3 is variable, and the variable distances d1, d2 and d3 are changed as shown in the following table in accordance with the focal length f of the entire system with zooming.
[0072]
[Table 11]
<Variable interval>

[0073]
The values of the parameters according to the conditional expressions (1) to (3) of the present invention described above in the third embodiment are as shown in the following table, and are within the range of the conditional expressions.
[0074]
[Table 12]
<Parameter value of conditional expression>

[0075]
FIG. 10 shows aberration diagrams in the third example.
[0076]
[Fourth embodiment]
FIG. 4 shows the configuration of the optical system of the zoom lens according to the fourth embodiment of the present invention.
The zoom lens shown in FIG. 4 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, and a ninth lens. A lens E9, a tenth lens E10, an eleventh lens E11, an aperture FA and an optical filter (including a cover glass) OF are provided. In this case, the first lens E1 to the third lens E3 constitute the first group optical system G1, the fourth lens E4 to the sixth lens E6 constitute the second group optical system G2, and the seventh lens E7 to E7. The eleventh lens E11 constitutes the third group optical system G3, and is supported by a common support frame or the like that is appropriate for each lens group, and operates integrally for each lens group during zooming or the like. The stop FA is disposed on the object side of the third group optical system G3 and operates integrally with the third group optical system G3. In addition, in order to avoid complication of explanation due to an increase in the number of digits of the reference code, each reference code for FIG. 4 is used independently for each embodiment. Therefore, even if a common reference code is attached, It is not necessarily the same configuration as the embodiment.
[0077]
In FIG. 4, for example, from the object side such as a subject, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an aperture FA, and a seventh lens are sequentially arranged. E7, eighth lens E8, ninth lens E9, tenth lens E10, eleventh lens E11, and optical filter OF are arranged in this order, and are imaged behind optical filter OF having various optical filtering functions. .
The first lens E1 is a negative meniscus lens that is convex on the object side, the second lens E2 is a positive meniscus lens that is convex on the object side, and the third lens E3 is convex on the object side. The first lens E1 and the second lens E2 are closely cemented two-lens cemented lenses, and a first group optical system G1 composed of the first lens E1 to the third lens E3. Exhibits a positive focal length as a whole. The fourth lens E4 is a negative meniscus lens convexly formed on the object side, the fifth lens E5 is a negative lens composed of a biconcave lens, and the sixth lens E6 is a positive lens composed of a biconvex lens. E5 and the sixth lens E6 are closely cemented two-piece cemented lenses, and the second group optical system G2 constituted by the fourth lens E4 to the sixth lens E6 exhibits a negative focal length as a whole. .
[0078]
The seventh lens E7 is a positive meniscus lens that is convex on the object side, the eighth lens E8 is a negative meniscus lens that is convex on the object side, the ninth lens E9 is a positive lens composed of a biconvex lens, The tenth lens E10 is a negative lens composed of a biconcave lens, the eleventh lens E11 is a positive lens composed of a biconvex lens, and the eighth lens E8 to the tenth lens E10 are three cemented lenses that are closely cemented. The third group optical system G3 configured by the seventh lens E7 to the eleventh lens E11 exhibits a positive focal length as a whole. The stop FA disposed between the second group optical system G2 and the third group optical system G3 operates integrally with the third group optical system G3, and the distance from the third group optical system G3 is constant. It is. The optical filter OF disposed on the image plane side of the eleventh lens E11 of the third group optical system G3 may include a cover glass of the solid-state image sensor 53 such as a CCD image sensor, and has various optical filtering functions. . In the fourth embodiment, the fourth surface, which is the object-side surface of the third lens E3 located closest to the image plane of the first group optical system G1, and the object closest to the second group optical system G3. The sixth surface, which is the object-side surface of the fourth lens E4, and the eighteenth surface, which is the object-side surface of the eleventh lens E11 located closest to the image plane of the third group optical system G3, are aspherical surfaces.
[0079]
As shown in FIG. 4, the movement of each group optical system G <b> 1 to G <b> 3 due to zooming between the wide-angle end, that is, the short focal length end, and the telephoto end, that is, the long focal length end, is the first group. The optical system G1 moves from the object side to the image plane side with the movement from the short focal length end to the intermediate focal length, and from the image plane side with the movement from the intermediate focal length to the long focal length end. While moving toward the object side, the second group optical system G2 moves from the object side toward the image plane side with the movement from the short focal length end to the long focal length end, and the third group optical system G3 moves from the image plane side toward the object side.
In the fourth embodiment, the focal length f, F number F, and half angle of view ω of the entire system are f = 5.900-23.600 and F = 0.04-3.72, respectively, by zooming. , Ω = 38.2 to 11.1. The optical characteristics associated with each optical surface and optical element are as shown in the following table.
[0080]
[Table 13]
<optical properties>

[0081]
The optical surfaces of the fourth surface, the sixth surface, and the eighteenth surface in Table 13 are aspheric surfaces, and the parameters according to the above-described equation (4) in each aspheric surface are as shown in the following table.
[0082]
[Table 14]
<Aspheric coefficient>

[0083]
The distance d1 between the first group optical system G1 and the second group optical system G2, the distance d2 between the second group optical system G2 and the stop FA, and between the third group optical system G3 and the optical filter OF The distance d3 is variable, and the variable distances d1, d2 and d3 are changed as shown in the following table in accordance with the focal length f of the entire system with zooming.
[0084]
[Table 15]
<Variable interval>

[0085]
The values of the parameters according to the conditional expressions (1) to (3) of the present invention described above in the fourth embodiment are as shown in the following table, and are within the range of the conditional expressions.
[0086]
[Table 16]
<Parameter value of conditional expression>

[0087]
FIG. 11 shows aberration diagrams in the fourth example.
[0088]
[Fifth embodiment]
FIG. 5 shows the configuration of an optical system of a zoom lens according to the fifth embodiment of the present invention.
The zoom lens shown in FIG. 5 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens. A lens E9, a tenth lens E10, an eleventh lens E11, an aperture FA and an optical filter (including a cover glass) OF are provided. In this case, the first lens E1 to the third lens E3 constitute the first group optical system G1, the fourth lens E4 to the sixth lens E6 constitute the second group optical system G2, and the seventh lens E7 to E7. The eleventh lens E11 constitutes the third group optical system G3, and is supported by a common support frame or the like that is appropriate for each lens group, and operates integrally for each lens group during zooming or the like. The stop FA is disposed on the object side of the third group optical system G3 and operates integrally with the third group optical system G3. In addition, in order to avoid complication of explanation due to an increase in the number of digits of the reference code, each reference code for FIG. 5 is used independently for each embodiment. It is not necessarily the same configuration as the embodiment.
[0089]
In FIG. 5, for example, from the object side such as a subject, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the aperture FA, and the seventh lens are sequentially arranged. E7, eighth lens E8, ninth lens E9, tenth lens E10, eleventh lens E11, and optical filter OF are arranged in this order, and are imaged behind optical filter OF having various optical filtering functions. .
The first lens E1 is a negative meniscus lens that is convex on the object side, the second lens E2 is a positive meniscus lens that is convex on the object side, and the third lens E3 is convex on the object side. The first lens E1 and the second lens E2 are closely cemented two-lens cemented lenses, and a first group optical system G1 composed of the first lens E1 to the third lens E3. Exhibits a positive focal length as a whole. The fourth lens E4 is a negative meniscus lens convexly formed on the object side, the fifth lens E5 is a negative lens composed of a biconcave lens, and the sixth lens E6 is a positive lens composed of a biconvex lens. E5 and the sixth lens E6 are closely cemented two-piece cemented lenses, and the second group optical system G2 constituted by the fourth lens E4 to the sixth lens E6 exhibits a negative focal length as a whole. .
[0090]
The seventh lens E7 is a positive lens composed of a biconvex lens, the eighth lens E8 is a negative meniscus lens formed convex on the object side, the ninth lens E9 is a positive lens composed of a biconvex lens, and the tenth lens E10 is The negative lens composed of a biconcave lens, and the eleventh lens E11 are positive lenses composed of a biconvex lens, and the eighth lens E8 to the tenth lens E10 are closely cemented three-element cemented lenses. The third group optical system G3 configured by the lenses E7 to E11 exhibits a positive focal length as a whole. The stop FA disposed between the second group optical system G2 and the third group optical system G3 operates integrally with the third group optical system G3, and the distance from the third group optical system G3 is constant. It is. The optical filter OF disposed on the image plane side of the eleventh lens E11 of the third group optical system G3 may include a cover glass of the solid-state image sensor 53 such as a CCD image sensor, and has various optical filtering functions. . In the fifth example, the fifth surface, which is the image surface side surface of the third lens E3 located closest to the image plane side of the first group optical system G1, is positioned closest to the object side of the third group optical system G3. The twelfth surface which is the object side surface of the seventh lens E7 and the eighteenth surface which is the object side surface of the eleventh lens E11 located closest to the image plane of the third group optical system G3 are aspherical surfaces. .
[0091]
As shown in FIG. 5, the movement of each group optical system G1 to G3 accompanying the zooming between the wide-angle end, that is, the short focal length end, and the telephoto end, that is, the long focal length end, is the first group. The optical system G1 moves from the object side to the image plane side with the movement from the short focal length end to the intermediate focal length, and from the image plane side with the movement from the intermediate focal length to the long focal length end. While moving toward the object side, the second group optical system G2 moves from the object side toward the image plane side with the movement from the short focal length end to the long focal length end, and the third group optical system G3 moves from the image plane side to the object side with the movement from the short focal length end to the intermediate focal length, and from the object side to the image plane side with the movement from the intermediate focal length to the long focal length end. Move towards.
In the fifth embodiment, the focal length f, F number F, and half angle of view ω of the entire system are f = 5.900-23.601 and F = 2.79-3.41, respectively, by zooming. , Ω = 38.2 to 11.1. The optical characteristics associated with each optical surface and optical element are as shown in the following table.
[0092]
[Table 17]
<optical properties>

[0093]
The optical surfaces of the fifth surface, the twelfth surface, and the eighteenth surface in Table 17 are aspheric surfaces, and the parameters relating to the above-described equation (4) in each aspheric surface are as shown in the following table.
[0094]
[Table 18]
<Aspheric coefficient>

[0095]
The distance d1 between the first group optical system G1 and the second group optical system G2, the distance d2 between the second group optical system G2 and the stop FA, and between the third group optical system G3 and the optical filter OF The distance d3 is variable, and the variable distances d1, d2 and d3 are changed as shown in the following table in accordance with the focal length f of the entire system with zooming.
[0096]
[Table 19]
<Variable interval>

[0097]
The values of the parameters according to the conditional expressions (1) to (3) of the present invention described above in the fifth embodiment are as shown in the following table, and are within the range of the conditional expressions.
[0098]
[Table 20]
<Parameter value of conditional expression>

[0099]
FIG. 12 shows aberration diagrams in the fifth example.
[0100]
[Sixth embodiment]
FIG. 6 shows the configuration of an optical system of a zoom lens according to the sixth embodiment of the present invention.
The zoom lens shown in FIG. 6 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens. A lens E9, a tenth lens E10, an eleventh lens E11, an aperture FA and an optical filter (including a cover glass) OF are provided. In this case, the first lens E1 to the third lens E3 constitute the first group optical system G1, the fourth lens E4 to the sixth lens E6 constitute the second group optical system G2, and the seventh lens E7 to E7. The eleventh lens E11 constitutes the third group optical system G3, and is supported by a common support frame or the like that is appropriate for each lens group, and operates integrally for each lens group during zooming or the like. The stop FA is disposed on the object side of the third group optical system G3 and operates integrally with the third group optical system G3.
In addition, in order to avoid complication of explanation due to an increase in the number of digits of the reference code, each reference code for FIG. 6 is used independently for each embodiment. Therefore, even if a common reference code is attached, It is not necessarily the same configuration as the embodiment.
[0101]
In FIG. 6, for example, in order from the object side such as a subject, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the aperture FA, and the seventh lens. E7, eighth lens E8, ninth lens E9, tenth lens E10, eleventh lens E11, and optical filter OF are arranged in this order, and are imaged behind optical filter OF having various optical filtering functions. .
The first lens E1 is a negative meniscus lens that is convex on the object side, the second lens E2 is a positive meniscus lens that is convex on the object side, and the third lens E3 is convex on the object side. The first lens E1 and the second lens E2 are closely cemented two-lens cemented lenses, and a first group optical system G1 composed of the first lens E1 to the third lens E3. Exhibits a positive focal length as a whole. The fourth lens E4 is a negative meniscus lens that is convex on the object side, the fifth lens E5 is a negative lens that is a biconcave lens, and the sixth lens E6 is a positive meniscus lens that is convex on the object side. The fifth lens E5 and the sixth lens E6 are two cemented lenses that are closely joined, and the second group optical system G2 constituted by the fourth lens E4 to the sixth lens E6 is negative as a whole. Of focal length.
[0102]
The seventh lens E7 is a positive lens composed of a biconvex lens, the eighth lens E8 is a negative lens composed of a biconcave lens, the ninth lens E9 is a positive lens composed of a biconvex lens, and the tenth lens E10 is a negative lens composed of a biconcave lens. The lens and the eleventh lens E11 are positive meniscus lenses that are convex on the object side, and the eighth lens E8 to the tenth lens E10 are closely cemented three-element cemented lenses. The third group optical system G3 configured by the lenses E7 to E11 exhibits a positive focal length as a whole. The stop FA disposed between the second group optical system G2 and the third group optical system G3 operates integrally with the third group optical system G3, and the distance from the third group optical system G3 is constant. It is. The optical filter OF disposed on the image plane side of the eleventh lens E11 of the third group optical system G3 may include a cover glass of the solid-state image sensor 53 such as a CCD image sensor, and has various optical filtering functions. . In the sixth example, the sixth surface, which is the object side surface of the fourth lens E4 located closest to the object side of the second group optical system G2, and the sixth surface located closest to the object side of the third group optical system G3. A twelfth surface that is the object side surface of the seventh lens E7 and a seventeenth surface that is the image surface side surface of the tenth lens E10 that is located closest to the image surface side of the three-piece cemented lens of the third group optical system G3. Each is aspherical.
[0103]
As shown in FIG. 6, the movement of each group optical system G <b> 1 to G <b> 3 accompanying zooming between the wide-angle end, that is, the short focal length end, and the telephoto end, that is, the long focal length end, is short focal length. Along with the movement from the end to the long focal length end, the first group optical system G1 moves from the image plane side toward the object side, and the second group optical system G2 moves from the object side toward the image plane side. The third group optical system G3 moves from the image plane side to the object side.
In the sixth embodiment, the focal length f, F number F, and half angle of view ω of the entire system are f = 5.900 to 35.404 and F = 3.60 to 3.88, respectively, by zooming. , Ω = 38.2 to 7.5. The optical characteristics associated with each optical surface and optical element are as shown in the following table.
[0104]
[Table 21]
<optical properties>

[0105]
The optical surfaces of the sixth surface, the twelfth surface and the seventeenth surface in Table 21 are aspheric surfaces, and the parameters relating to the above-described equation (4) in each aspheric surface are as shown in the following table.
[0106]
[Table 22]
<Aspheric coefficient>

[0107]
The distance d1 between the first group optical system G1 and the second group optical system G2, the distance d2 between the second group optical system G2 and the stop FA, and between the third group optical system G3 and the optical filter OF The distance d3 is variable, and the variable distances d1, d2 and d3 are changed as shown in the following table in accordance with the focal length f of the entire system with zooming.
[0108]
[Table 23]
<Variable interval>

[0109]
The values of the parameters according to the conditional expressions (1) to (3) of the present invention described above in the sixth embodiment are as shown in the following table, and are within the range of the conditional expressions.
[0110]
[Table 24]
<Parameter value of conditional expression>

FIG. 13 shows aberration diagrams in the sixth example.
[0111]
[Seventh embodiment]
FIG. 7 shows the configuration of the optical system of a zoom lens according to the seventh embodiment of the present invention.
The zoom lens shown in FIG. 7 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, and a ninth lens. A lens E9, a tenth lens E10, an eleventh lens E11, an aperture FA and an optical filter (including a cover glass) OF are provided. In this case, the first lens E1 to the third lens E3 constitute the first group optical system G1, the fourth lens E4 to the sixth lens E6 constitute the second group optical system G2, and the seventh lens E7 to E7. The eleventh lens E11 constitutes the third group optical system G3, and is supported by a common support frame or the like that is appropriate for each lens group, and operates integrally for each lens group during zooming or the like. The stop FA is disposed on the object side of the third group optical system G3 and operates integrally with the third group optical system G3. In addition, in order to avoid complication of explanation due to an increase in the number of digits of the reference code, each reference code for FIG. 7 is used independently for each embodiment. Therefore, even if a common reference code is attached, It is not necessarily the same configuration as the embodiment.
[0112]
In FIG. 7, for example, in order from the object side such as a subject, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the aperture FA, and the seventh lens. E7, eighth lens E8, ninth lens E9, tenth lens E10, eleventh lens E11, and optical filter OF are arranged in this order, and are imaged behind optical filter OF having various optical filtering functions. .
The first lens E1 is a negative meniscus lens that is convex on the object side, the second lens E2 is a positive meniscus lens that is convex on the object side, and the third lens E3 is convex on the object side. The first lens E1 and the second lens E2 are closely cemented two-lens cemented lenses, and a first group optical system G1 composed of the first lens E1 to the third lens E3. Exhibits a positive focal length as a whole. The fourth lens E4 is a negative meniscus lens convexly formed on the object side, the fifth lens E5 is a negative lens composed of a biconcave lens, and the sixth lens E6 is a positive lens composed of a biconvex lens. E5 and the sixth lens E6 are closely cemented two-piece cemented lenses, and the second group optical system G2 constituted by the fourth lens E4 to the sixth lens E6 exhibits a negative focal length as a whole. .
[0113]
The seventh lens E7 is a positive lens composed of a biconvex lens, the eighth lens E8 is a negative meniscus lens formed convex on the object side, the ninth lens E9 is a positive lens composed of a biconvex lens, and the tenth lens E10 is The negative lens composed of a biconcave lens, and the eleventh lens E11 are positive lenses composed of a biconvex lens, and the eighth lens E8 to the tenth lens E10 are closely cemented three-element cemented lenses. The third group optical system G3 configured by the lenses E7 to E11 exhibits a positive focal length as a whole. The stop FA disposed between the second group optical system G2 and the third group optical system G3 operates integrally with the third group optical system G3, and the distance from the third group optical system G3 is constant. It is. The optical filter OF disposed on the image plane side of the eleventh lens E11 of the third group optical system G3 may include a cover glass of the solid-state image sensor 53 such as a CCD image sensor, and has various optical filtering functions. . In the seventh example, the sixth surface, which is the object side surface of the fourth lens E4 located closest to the object side of the second group optical system G2, and the sixth surface located closest to the object side of the third group optical system G3. The twelfth surface that is the object side surface of the seventh lens E7 and the eighteenth surface that is the object side surface of the eleventh lens E11 located closest to the image plane of the third group optical system G3 are aspherical surfaces.
[0114]
As shown in FIG. 7, the movement of each group optical system G <b> 1 to G <b> 3 due to zooming between the wide-angle end, i.e., the short focal length end, and the telephoto end, i.e., the long focal length end, Along with the movement from the end to the long focal length end, the first group optical system G1 moves from the image plane side toward the object side, and the second group optical system G2 moves from the object side toward the image plane side. The third group optical system G3 moves from the image plane side to the object side.
In the seventh embodiment, the focal length f, F number F, and half angle of view ω of the entire system are f = 5.898 to 23.605 and F = 2.79 to 3.45, respectively, by zooming. , Ω = 38.3 to 11.1. The optical characteristics associated with each optical surface and optical element are as shown in the following table.
[0115]
[Table 25]
<optical properties>

[0116]
The optical surfaces of the sixth surface, the twelfth surface and the eighteenth surface in Table 25 are aspheric surfaces, and the parameters relating to the above-described equation (4) in each aspheric surface are as shown in the following table.
[0117]
[Table 26]
<Aspheric coefficient>

[0118]
The distance d1 between the first group optical system G1 and the second group optical system G2, the distance d2 between the second group optical system G2 and the stop FA, and between the third group optical system G3 and the optical filter OF The distance d3 is variable, and the variable distances d1, d2 and d3 are changed as shown in the following table in accordance with the focal length f of the entire system with zooming.
[0119]
[Table 27]
<Variable interval>

[0120]
The values of the parameters according to the conditional expressions (1) to (3) of the present invention described above in the seventh embodiment are as shown in the following table, and are within the range of the conditional expressions.
[0121]
[Table 28]
<Parameter value of conditional expression>

FIG. 14 shows aberration diagrams in the seventh example.
[0122]
In the sixth embodiment described above, the aperture stop at the long focal length end is made larger than the short focal length, and the F number at the long focal length end is made small.
In addition, each lens described above has a diaphragm for shielding a part of the light flux having an intermediate angle of view between the second group optical system G2 and the third group optical system G3 in a variable magnification region other than the long focal length end. It is possible to arrange. FIG. 15 shows an example of an aberration diagram in the case where the above-described sixth embodiment is provided with a diaphragm for shielding light. In this case, the position of the stop for light shielding is as follows.
Short focal length end: 10 mm from the second group optical system G2 to the image plane side
Intermediate focal length: 1 mm from the second group optical system G2 to the image plane side
This example shows an example in which the aperture position and aperture diameter for light shielding are changed in order to shield a part of the intermediate image height light beam from the short focal length end to the intermediate focal length. Accordingly, it is needless to say that the zooming area that is shielded by fixing the position and diameter may be, for example, only the short focal length end.
[0123]
As is clear from each of the above-described embodiments, the zoom lens according to the present invention has a small number of lenses of 10 to 11 and is a very compact lens, which can cope with resource saving and has a short focal length. A wide angle of view with a half angle of view of 38 ° or more and a zoom ratio of about 3 to 6 times, and a high zoom ratio, it can handle image sensors with more than 3 million pixels over the entire zoom range. Thus, the chromatic aberration and the initial aberration can be corrected satisfactorily. In addition, all lens materials are made of optically stable optical glass that does not contain harmful substances such as lead and arsenic, so the materials can be recycled and there is no risk of water contamination from waste liquid during processing. , Global environmental conservation becomes possible. In addition, by using the zoom lens of each of the above embodiments as a photographing lens in a camera, it achieves significant downsizing, weight reduction, and cost reduction while maintaining high performance as a camera and achieves power saving. It becomes possible.
By adding a communication function to such a camera function and configuring a portable information terminal device, the portable information terminal device is significantly reduced in size, weight and cost, and achieves power saving. It becomes possible to do.
[0124]
【The invention's effect】
  As described above, according to the present invention, the half angle of view at the short focal length end is as wide as 38 ° or more over the entire zoom range, while having a high zoom ratio exceeding 3 times, and 3 million pixels over the entire zoom range. With high resolution imaging performance compatible with the above high-density imaging devices, the total lens length and lens outer diameter are very small, and the number of lenses can be reduced to about 10 to save resources. In addition, all lenses can be made of optically stable glass that is chemically stable and free of harmful substances such as lead and arsenic. Zoom lens that takes into account the global environment and is free from the risk of water pollution due to waste water of the liquid, and the zoom lensImaging deviceAnd a portable information terminal device can be provided.
[0125]
  That is, according to the zoom lens of the first aspect of the present invention, the first group optical system having a positive refractive power, the second group optical system having a negative refractive power, and the third group optical having a positive refractive power. Are arranged in order from the object side to the image plane side, and have a stop that moves integrally with the third group optical system on the object side of the third group optical system, and has a short focal length end, Along with the zooming between the long focal length end, the distance between the first group optical system and the second group optical system is minimized at the short focal length end, and the second at the long focal length end. In a zoom lens that moves at least the first group optical system and the third group optical system so that the distance between the group optical system and the third group optical system is minimized,
  The third group optical system is
In order from the object side, one positive lens,Negative lensAnd positivelensAnd negativeThree-piece cemented lens formed by sequentially arranging and cementing lenses, 1 Consists of one positive lens,
The refractive index of the positive lens of the three-piece cemented lens of the third group optical system is Np, and the average refractive index of the two negative lenses of the three-piece cemented lens of the third group optical system is Nn. Νp is the positive Abbe number of the three cemented lenses of the third group optical system, and the average is the Abbe number of the two negative lenses of the three cemented lenses of the third group optical system. Is a conditional expression:
  −0.22 <Np−Nn <0 (2)
    3 <νp−νn <36 (3)
  SatisfyAs a result, it has a high zoom ratio exceeding 3 times, and the half angle of view at the short focal length end is as wide as 38 ° or more, and it can be used for a high-density image sensor with 3 million pixels or more. Realizing the imaging performance of resolving power, the total lens length and lens outer diameter are very small, the number of lenses can be reduced to about 10, and it is possible to cope with resource saving. The lens can be made of optical glass that is chemically stable and does not contain harmful substances such as lead and arsenic, and can be recycled, and there is no risk of water pollution due to waste liquid during processing. In particular, a great effect can be obtained in correcting chromatic aberration of magnification that occurs with a wide angle of view.,
In particular, by satisfying conditional expression (2) and conditional expression (3), it becomes possible to achieve good chromatic aberration correction while maintaining a good balance with other aberrations at low cost. Since the third group optical system further includes at least one positive lens on the object side and the image plane side of the three-piece cemented lens, in particular, the third group optical system is positive, negative, positive, negative, positive. As a configuration, refractive power is arranged in a well-balanced manner to suppress the occurrence of aberrations on each lens surface, and performance degradation due to manufacturing errors such as decentration can be minimized.The
[0126]
According to the zoom lens of claim 2 of the present invention, in the zoom lens of claim 1, the first group optical system has an intermediate focal length state between a short focal length end and a long focal length end. By moving in a convex shape toward the image surface side with the subsequent zooming operation, zooming is performed mainly by moving the second group optical system, and zooming by moving the other groups Further, it is possible to obtain a favorable lens performance by correcting the fluctuation of the image plane position accompanying the zooming.
According to the zoom lens of claim 3 of the present invention, in the zoom lens of claim 2, the first group optical system is closest to the image plane at an intermediate focal length other than the short focal length end and the long focal length end. By moving to the position, in particular, the first group optical system can correct image plane position fluctuation accompanying zooming, and obtain good lens performance.
[0127]
  According to a zoom lens of a fourth aspect of the present invention, in the zoom lens of any one of the first to third aspects, the most object side negative of the three-piece cemented lens of the third group optical system By forming the lens with a strong concave surface facing the image surface side, it is possible to suppress unnecessary aberrations and to effectively correct mainly spherical aberration and coma aberration, particularly with a relatively simple configuration. Is possible.
  According to the zoom lens of claim 5 of the present invention, in the zoom lens of any one of claims 1 to 4, the miniaturization is particularly realized by satisfying the conditional expression (1). In addition, it is possible to effectively suppress performance degradation due to manufacturing errors such as aberration generation and decentering in each group optical system..
[0128]
  BookClaims of the invention6According to the zoom lens of claimAny one of 1-5In the zoom lens, at least one positive lens among the positive lenses disposed on the object side and the image plane side of the three-piece cemented lens has an aspherical surface, and in particular, on-axis and off-axis light fluxes. Can be arranged at positions separated from each other, and astigmatism correction can be effectively performed mainly.
  Claims of the invention7According to the zoom lens of claim 1, claims 1 to6In the zoom lens according to any one of the above, by adding a positive lens and a negative lens, which are necessary for aberration correction, to each of the first group optical system and the second group optical system, the entire zoom lens configuration By including at least one positive lens and one negative lens that suppress each aberration to a small size while simplifying, downsizing, and reducing costs, it is possible to correct aberrations appropriately and achieve downsizing in particular. It becomes possible.
[0129]
  Further, the claims of the present invention8According to the imaging apparatus of claim 1, the photographing optical system is defined in claims 1 to 1.7By using the zoom lens according to any one of the above, the half angle of view at the short focal length end is as wide as 38 ° or more while having a high zoom ratio exceeding 3 times, and 3 million in addition. Realizes high-resolution imaging performance compatible with high-density image sensors with pixels or more, extremely reduces the overall lens length and lens outer diameter, and reduces the number of lenses to about 10 to save. It is possible to cope with resource recycling, and all lenses can be made of optical glass that is chemically stable and does not contain harmful substances such as lead and arsenic, making it possible to recycle materials. There is no fear of water pollution due to waste liquid during processing, and in particular, an imaging device that is compact, has a high zoom ratio, high image quality, and low power consumption can be provided.
  Claims of the invention9According to the imaging device of claim8In this imaging apparatus, when the imaging apparatus is a digital camera including a function of converting a captured image into digital information, it is possible to realize a particularly compact, high zoom ratio and high image quality by using a printer. Even when the subject image recorded by the digital camera according to the present invention is output, it is possible to obtain an output with the same or higher quality than the image quality of the conventional silver lead camera, that is, the image quality.
[0130]
  Further, the claims of the present invention10According to the portable information terminal device of claim 1, as a photographing optical system of the camera function unit, claims 1 to7By using the zoom lens according to any one of the above, the half angle of view at the short focal length end is as wide as 38 ° or more while having a high zoom ratio exceeding 3 times, and 3 million in addition. Realizes high-resolution imaging performance compatible with high-density image sensors with pixels or more, extremely reduces the overall lens length and lens outer diameter, and reduces the number of lenses to about 10 to save. It is possible to cope with resource recycling, and all lenses can be made of optical glass that is chemically stable and does not contain harmful substances such as lead and arsenic, making it possible to recycle materials. It is possible to provide a portable information terminal device that is capable of obtaining recording data that is extremely small and that is capable of obtaining high-quality recording data without fear of water contamination due to waste liquid during processing.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an optical system configuration of a first example of a zoom lens according to the first embodiment of the present invention;
FIG. 2 is a configuration diagram showing an optical system configuration of a second example of the zoom lens according to the first embodiment of the present invention;
FIG. 3 is a configuration diagram showing an optical system configuration of a third example of the zoom lens according to the first embodiment of the present invention;
FIG. 4 is a configuration diagram showing an optical system configuration of a fourth example of the zoom lens according to the first embodiment of the present invention;
FIG. 5 is a configuration diagram showing an optical system configuration of a fifth example of the zoom lens according to the first embodiment of the present invention;
FIG. 6 is a configuration diagram showing an optical system configuration of a sixth example of the zoom lens according to the first embodiment of the present invention;
FIG. 7 is a configuration diagram showing an optical system configuration of a seventh example of the zoom lens according to the first embodiment of the present invention;
FIG. 8 is an aberration diagram showing aberration characteristics of the zoom lens of FIG. 1;
FIG. 9 is an aberration diagram showing aberration characteristics of the zoom lens of FIG. 2;
10 is an aberration diagram showing aberration characteristics of the zoom lens in FIG. 3; FIG.
11 is an aberration diagram showing aberration characteristics of the zoom lens of FIG. 4. FIG.
12 is an aberration diagram showing aberration characteristics of the zoom lens of FIG. 5. FIG.
13 is an aberration diagram showing aberration characteristics of the zoom lens of FIG. 6. FIG.
14 is an aberration diagram showing aberration characteristics of the zoom lens of FIG. 7. FIG.
FIG. 15 is an aberration diagram showing aberration characteristics when a light beam having an intermediate image height at the short focal length end and intermediate focal length in the zoom lens of FIG. 6 is shielded by a diaphragm.
FIG. 16 is a schematic configuration diagram conceptually showing the configuration of a digital camera provided with a range finder type optical finder according to a second embodiment of the present invention.
FIG. 17 is a schematic configuration diagram conceptually showing the configuration of a digital camera including a single-lens reflex type optical viewfinder according to a third embodiment of the present invention.
FIG. 18 is a block diagram schematically showing a control configuration of a digital camera or a portable information terminal device according to second and third embodiments of the present invention.
[Explanation of symbols]
G1 first group optical system
G2 Second group optical system
G3 Third group optical system
FA aperture
OF optical filter
E1 first lens
E2 second lens
E3 3rd lens
E4 4th lens
E5 5th lens
E6 6th lens
E7 7th lens
E8 8th lens
E9 9th lens
E10 10th lens
E11 Eleventh lens
1-21 Each side
FA aperture
OF optical filter
51 Imaging device
52 Zoom optical system for photography
52a Shooting zoom lens
52b Mechanical drive mechanism
53 Solid-state image sensor
54 Signal processor
55 A / D (analog-digital) converter
56 Digital signal processor
57 Image memory
58 Control unit
59 Motor driver
60 Timing control circuit
61 Data recording part
62 Display device
63 Strobe device
64 Communication interface (I / F)
71, 81 finder optical system
82 Movable reflex mirror
83 Focusing screen
84 Penta prism
85 Eyepiece

Claims (10)

A first group optical system having a positive refractive power, a second group optical system having a negative refractive power, and a third group optical system having a positive refractive power are sequentially applied from the object side to the image plane side. And a stop that moves integrally with the third group optical system on the object side of the third group optical system, and is accompanied by zooming between the short focal length end and the long focal length end. The distance between the first group optical system and the second group optical system is minimized at the short focal length end, and the distance between the second group optical system and the third group optical system at the long focal length end. In a zoom lens that moves at least the first group optical system and the third group optical system so as to be minimized,
The third group optical system is
In order from the object side, it is composed of one positive lens, a negative lens and a positive lens and a negative lens and sequentially arranged to bonded cemented triplet formed by a single positive lens,
The refractive index of the positive lens of the three-piece cemented lens of the third group optical system is Np, and the average refractive index of the two negative lenses of the three-piece cemented lens of the third group optical system is Nn. Νp is the positive Abbe number of the three cemented lenses of the third group optical system, and the average is the Abbe number of the two negative lenses of the three cemented lenses of the third group optical system. Is a conditional expression:
−0.22 <Np−Nn <0 (2)
3 <νp−νn <36 (3)
A zoom lens characterized by satisfying   The first group optical system moves in a convex shape toward the image plane side with a zooming operation through an intermediate focal length state between a short focal length end and a long focal length end. The zoom lens according to claim 1.   3. The zoom lens according to claim 2, wherein the first group optical system moves to a position closest to the image plane at an intermediate focal length other than the short focal length end and the long focal length end.   The negative lens closest to the object side of the three-piece cemented lens of the third group optical system is formed with a strong concave surface facing the image surface side. The zoom lens according to claim 1. The amount of change in the group interval between the first group optical system and the second group optical system in the entire zoom range is K12, the combined focal length of the entire system at the short focal length end is fw, and the long focal length end is If the total focal length of the entire system is ft, the conditional expression:
0.6 <K12 / (fw + ft) <1.2 (1)
The zoom lens according to claim 1, wherein the zoom lens satisfies the following. At least one positive lens of the positive lens disposed on the object side and image plane side of the three-element cemented lens, of the claims 1 to 5, characterized in that it has an aspherical surface The zoom lens according to any one of the above. Each of said first group optical system and the second group optical system, to any one of claims 1 to claim 6 in which a positive lens and a negative lens, characterized in that it contains one by at least one The described zoom lens. An imaging apparatus using the zoom lens according to any one of claims 1 to 7 as a photographing optical system. The imaging apparatus according to claim 8 , wherein the imaging apparatus is a digital camera including a function of using captured images as digital information. A portable information terminal device using the zoom lens according to any one of claims 1 to 7 as a photographing optical system of a camera function unit.

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