JP4882260B2 - Zoom lens - Google Patents
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- JP4882260B2 JP4882260B2 JP2005098737A JP2005098737A JP4882260B2 JP 4882260 B2 JP4882260 B2 JP 4882260B2 JP 2005098737 A JP2005098737 A JP 2005098737A JP 2005098737 A JP2005098737 A JP 2005098737A JP 4882260 B2 JP4882260 B2 JP 4882260B2
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本発明は、固体撮像素子等を撮像素子としたビデオカメラや電子スチルカメラなどに用いられる小型のズームレンズに関する。 The present invention relates to a small zoom lens used for a video camera, an electronic still camera, or the like using a solid-state imaging device or the like as an imaging device.
昨今、固体撮像素子等を撮像素子としたビデオカメラや電子スチルカメラなど高画素化が進み撮影レンズの高い光学性能への要求が高くなり、また撮影の利便性から高変倍比のズーム、携帯の利便性から小型化への要求も高くなっており、それらを同時に満たすことが求められている。また、撮影者の撮影表現の可能性を広げる上で、広角端状態の画角が７０度を越えるような広画角を有するズームレンズへの要求も高まっている。その中で、広角端状態の画角が７０度を越え、変倍比が４倍程度以上の高変倍比を持つズームレンズとしては、レンズ群数が５群以上で、最も物体側のレンズ群が正屈折力を持つタイプが提案されている（例えば、特許文献１参照。）。
しかしながら、特許文献１に開示された実施例では、広角端状態の画角が７０度を越え、さらに高変倍比は確保されているものの、広角端状態から望遠端状態までの焦点距離全域に亘って光学性能が十分に高いとは言えず、また小型化が十分とは言えなかった。
However, in the embodiment disclosed in
本発明は、上記課題に鑑みて行われたものであり、広角端状態の画角が７０度を越え、変倍比が４倍程度以上の高変倍比を持ち、高い光学性能を有する固体撮像素子等を撮像素子としたビデオカメラや電子スチルカメラなどに適した小型のズームレンズを提供することを目的としている。 The present invention has been made in view of the above problems, and has a high zoom ratio with an angle of view in the wide-angle end state exceeding 70 degrees, a zoom ratio of about 4 times or more, and high optical performance. An object of the present invention is to provide a small zoom lens suitable for a video camera, an electronic still camera, or the like that uses an image sensor as an image sensor.
上記目的を達成するために、本発明は、光軸に沿って物体側から順に、正屈折力を有する第１レンズ群と、負屈折力を有する第２レンズ群と、正屈折力を有する第３レンズ群と、正屈折力を有する第４レンズ群と、正屈折力を有する第５レンズ群とからなり、広角端状態から望遠端状態までズーミングする際に、無限遠合焦状態において、光軸に沿って、前記第１レンズ群と前記第２レンズ群との空気間隔は増加し、前記第２レンズ群と前記第３レンズ群との空気間隔は減少し、前記第３レンズ群と前記第４レンズ群との空気間隔は変化し、前記第４レンズ群と前記第５レンズ群との空気間隔は増加するように、前記第１レンズ群は像面に対して移動し、前記第２レンズ群は像面側に移動した後、物体側に移動するような軌跡で移動し、前記第３レンズ群は物体側に移動し、前記第４レンズ群は物体側に移動し、光軸に沿って物体側から順に、前記第３レンズ群は正屈折力を有する第３ａレンズ群と、開口絞りと、第３ｂレンズ群とを有し、光軸に沿って物体側から順に、前記第３ａレンズ群は負屈折力を有するレンズと正屈折力を有するレンズから成る接合レンズのみで構成され、前記第３ｂレンズ群は正屈折力を有するレンズと負屈折力を有するレンズから成る接合レンズのみで構成され、以下の条件を満足することを特徴とするズームレンズを提供する。
７．９３≦ｆ１／ｆＷ＜１２．８
５．８＜ｆ１／（−ｆ２）＜１０．０
３．０＜ｆ５／ｆＷ＜１０．０
但し、ｆＷは広角端状態における前記ズームレンズ全系の焦点距離、ｆ１は前記第１レンズ群の焦点距離、ｆ２は前記第２レンズ群の焦点距離、ｆ５は前記第５レンズ群の焦点距離を表す。
In order to achieve the above object, according to the present invention, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a first lens group having a positive refractive power. a third lens group, a fourth lens group having positive refractive power and a fifth lens group having positive refractive power, upon zooming from the wide-angle end state to the telephoto end state, in an infinity in-focus condition, light Along the axis, the air gap between the first lens group and the second lens group increases, the air gap between the second lens group and the third lens group decreases, and the third lens group and the The first lens group moves relative to the image plane so that the air gap between the fourth lens group changes and the air gap between the fourth lens group and the fifth lens group increases, and the second lens group moves toward the image plane. After moving to the image plane side, the lens group moves along a trajectory that moves toward the object side. Third lens unit moves toward the object side, the fourth lens group moves toward the object side, in order from the object side along the optical axis, the third lens group and the 3a lens group having positive refractive power, the aperture A diaphragm and a 3b lens group, and in order from the object side along the optical axis, the 3a lens group is composed of only a cemented lens including a lens having a negative refractive power and a lens having a positive refractive power; The third lens group includes only a cemented lens including a lens having positive refracting power and a lens having negative refracting power, and satisfies the following conditions.
7.93 ≦ f1 / fW <12.8
5.8 <f1 / (− f2) <10.0
3.0 <f5 / fW <10.0
Where fW is the focal length of the entire zoom lens system in the wide-angle end state, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and f5 is the focal length of the fifth lens group. To express.
また、本発明にかかるズームレンズでは、無限遠合焦状態において、前記第３レンズ群と前記第４レンズ群の空気間隔は、光軸に沿って少なくとも広角端状態よりも望遠端状態の方が小さくなることが好ましい。 In the zoom lens according to the present invention, in the infinitely focused state, the air distance between the third lens group and the fourth lens group is at least in the telephoto end state along the optical axis than in the wide-angle end state. It is preferable to be smaller.
また、本発明にかかるズームレンズでは、広角端状態から望遠端状態までズーミングする際に、無限遠合焦状態において、前記第３レンズ群と前記第４レンズ群との空気間隔は、光軸に沿って減少することが好ましい。 In the zoom lens according to the present invention, when zooming from the wide-angle end state to the telephoto end state, the air space between the third lens group and the fourth lens group is in the optical axis in the infinite focus state. It is preferable to decrease along.
また、本発明にかかるズームレンズでは、広角端状態から望遠端状態までズーミングする際に、無限遠合焦状態において、前記第５レンズ群は、像面に対して光軸に沿って移動することが好ましい。 In the zoom lens according to the present invention, when zooming from the wide-angle end state to the telephoto end state, the fifth lens group moves along the optical axis with respect to the image plane in the infinite focus state. Is preferred.
また、本発明にかかるズームレンズでは、無限遠合焦状態において、前記第５レンズ群は、光軸に沿って少なくとも広角端状態よりも望遠端状態の方が物体側にあることが好ましい。 In the zoom lens according to the present invention, in the infinitely focused state, it is preferable that the fifth lens group is at the telephoto end state at least at the telephoto end state along the optical axis.
また、本発明にかかるズームレンズは、以下の条件を満足することが好ましい。
−０．５０＜ｆ３ａ／ｆ３ｂ＜０．８０
但し、ｆ３ａは前記第３ａレンズ群の焦点距離、ｆ３ｂは前記第３ｂレンズ群の焦点距離を表す。
In addition, the zoom lens according to the present invention preferably satisfies the following conditions.
-0.50 <f3a / f3b <0.80
However, f3a represents the focal length of the 3a lens group, and f3b represents the focal length of the 3b lens group.
また、本発明にかかるズームレンズでは、前記第２レンズ群は非球面レンズを含むことが好ましい。 In the zoom lens according to the present invention, it is preferable that the second lens group includes an aspheric lens.
また、本発明にかかるズームレンズでは、前記第４レンズ群は非球面レンズを含むことが好ましい。 In the zoom lens according to the present invention, it is preferable that the fourth lens group includes an aspheric lens.
本発明によれば、広角端状態の画角が７０度を越え、変倍比が４倍程度以上の高変倍比を持ち、高い光学性能を有する固体撮像素子等を撮像素子としたビデオカメラや電子スチルカメラなどに適した小型のズームレンズを提供することができる。 According to the present invention, a video camera using a solid-state imaging device or the like having a high zooming ratio with an angle of view exceeding 70 degrees, a zooming ratio of about 4 times or more, and high optical performance. And a small zoom lens suitable for an electronic still camera or the like.
以下、本発明の実施の形態に関し説明する。 Hereinafter, embodiments of the present invention will be described.
固体撮像素子等を撮像素子としたビデオカメラや電子スチルカメラなどでは、固体撮像素子の特性上の要求として、ズームレンズの射出瞳位置を像面から遠くする必要がある。このため像面側に近いレンズ群は全体として正の屈折力を持つことが好ましい。 In a video camera, an electronic still camera, or the like that uses a solid-state imaging device or the like as an imaging device, the exit pupil position of the zoom lens needs to be far from the image plane as a requirement on the characteristics of the solid-state imaging device. For this reason, it is preferable that the lens group close to the image plane side has a positive refractive power as a whole.
本発明の実施の形態にかかるズームレンズは、光軸に沿って物体側から順に、正屈折力を有する第１レンズ群と、負屈折力を有する第２レンズ群と、正屈折力を有する第３レンズ群と、正屈折力を有する第４レンズ群と、正屈折力を有する第５レンズ群とを有する構成とすることで、射出瞳位置を像面から遠くしている。 The zoom lens according to the embodiment of the present invention includes, in order from the object side along the optical axis, a first lens group having positive refractive power, a second lens group having negative refractive power, and a first lens group having positive refractive power. By adopting a configuration having three lens groups, a fourth lens group having positive refracting power, and a fifth lens group having positive refracting power, the exit pupil position is far from the image plane.
また、広角端状態から望遠端状態までズーミングする際に、無限遠合焦状態において、光軸に沿って、第１レンズ群と第２レンズ群との空気間隔は増加し、第２レンズ群と第３レンズ群との空気間隔は減少し、第３レンズ群と第４レンズ群との空気間隔は変化し、第４レンズ群と第５レンズ群との空気間隔は増加するように、第１レンズ群は像面に対して移動し、第２レンズ群は像面側に移動した後、物体側に移動するような軌跡で移動し、第３レンズ群は物体側に移動し、第４レンズ群は物体側に移動することによって、効率的に変倍効果を得ることができる。 Further, when zooming from the wide-angle end state to the telephoto end state, in the infinite focus state, the air space between the first lens group and the second lens group increases along the optical axis, and the second lens group The air gap between the third lens group decreases, the air gap between the third lens group and the fourth lens group changes, and the air gap between the fourth lens group and the fifth lens group increases. The lens group moves relative to the image plane, the second lens group moves toward the image plane side, and then moves along a locus that moves toward the object side, the third lens group moves toward the object side, and the fourth lens By moving the group to the object side, a zooming effect can be obtained efficiently.
また、本実施の形態にかかるズームレンズは、以下の条件式（１）〜（３）を満足することによって、さらに高い光学性能を持ちながら、広角端状態の画角が７０度を越え、変倍比が４倍程度以上の高変倍比を確保した小型ズームレンズを可能にしている。
（１）７．０＜ｆ１／ｆＷ＜１２．８
（２）５．８＜ｆ１／（−ｆ２）＜１０．０
（３）３．０＜ｆ５／ｆＷ＜１０．０
但し、ｆＷは広角端状態におけるズームレンズ全系の焦点距離、ｆ１は第１レンズ群の焦点距離、ｆ２は第２レンズ群の焦点距離、ｆ５は第５レンズ群の焦点距離を表す。
In addition, the zoom lens according to the present embodiment satisfies the following conditional expressions (1) to (3), so that the angle of view in the wide-angle end state exceeds 70 degrees while having higher optical performance. This enables a small zoom lens that has a high zoom ratio of about 4 times or more.
(1) 7.0 <f1 / fW <12.8
(2) 5.8 <f1 / (− f2) <10.0
(3) 3.0 <f5 / fW <10.0
However, fW represents the focal length of the entire zoom lens system in the wide-angle end state, f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, and f5 represents the focal length of the fifth lens group.
条件式（１）は、第１レンズ群の最適な焦点距離の範囲を規定するための条件式である。 Conditional expression (1) is a conditional expression for defining an optimum focal length range of the first lens group.
条件式（１）の上限値を上回った場合、第１レンズ群の焦点距離が相対的に長くなるため、第１レンズ群が変倍に対し効率的に寄与できなくなり、変倍比が４倍程度以上の高変倍比を確保できない。また、第１レンズ群の移動量が大きくなることによってズーミングの際に第１レンズ群で発生する収差の変動が大きくなり、広角端状態から望遠端状態までの全ズーム範囲において収差を低く抑えることが困難となる。また、第１レンズ群の移動量が大きいために小型化できない。 When the upper limit of conditional expression (1) is exceeded, the focal length of the first lens group becomes relatively long, so the first lens group cannot efficiently contribute to zooming, and the zoom ratio is 4 times. It is not possible to secure a high zoom ratio that is higher than the above. In addition, as the amount of movement of the first lens group increases, the variation in aberration generated in the first lens group during zooming increases, and the aberration is kept low in the entire zoom range from the wide-angle end state to the telephoto end state. It becomes difficult. Moreover, since the movement amount of the first lens group is large, it cannot be reduced in size.
条件式（１）の下限値を下回った場合、第１レンズ群の焦点距離が相対的に短くなるため、広角端状態における第１レンズ群への入射軸外光線と光軸との成す角が小さくなり、広角端状態で７０度を越えた画角を実現しようとすると、第１レンズ群の径が過度に大きくなり小型化できない。また、第１レンズ群で発生する収差が大きくなりすぎて高い光学性能を得ることができない。 If the lower limit value of conditional expression (1) is not reached, the focal length of the first lens group becomes relatively short, so that the angle formed by the off-axis light beam on the first lens group and the optical axis in the wide-angle end state is If it becomes small and an angle of view exceeding 70 degrees is realized in the wide-angle end state, the diameter of the first lens group becomes excessively large and cannot be reduced in size. In addition, the aberration generated in the first lens group becomes too large to obtain high optical performance.
なお、本発明の効果をより確実にする為に、条件式（１）の上限値を１２．０にすることが好ましい。また、本発明の効果をより確実にする為に、条件式（１）の下限値を７．５にすることが好ましい。 In order to secure the effect of the present invention, it is preferable to set the upper limit of conditional expression (1) to 12.0. In order to secure the effect of the present invention, it is preferable to set the lower limit of conditional expression (1) to 7.5.
条件式（２）は、第１レンズ群と第２レンズ群の最適な焦点距離比を規定するための条件式である。 Conditional expression (2) is a conditional expression for defining an optimum focal length ratio between the first lens group and the second lens group.
条件式（２）の上限値を上回った場合、第１レンズ群の焦点距離が相対的に長くなるため、第１レンズ群が変倍に対し効率的に寄与できなくなり、変倍比が４倍程度以上の高変倍比を確保できない。また、第１レンズ群の移動量が大きくなることによってズーミングの際に第１レンズ群で発生する収差の変動が大きくなり、広角端状態から望遠端状態までの全ズーム範囲において収差を低く抑えることが困難となる。また、第１レンズ群の移動量が大きいために小型化できない。 When the upper limit of conditional expression (2) is exceeded, the focal length of the first lens group becomes relatively long, so the first lens group cannot efficiently contribute to zooming, and the zoom ratio is 4 times. It is not possible to secure a high zoom ratio that is higher than the above. In addition, as the amount of movement of the first lens group increases, the variation in aberration generated in the first lens group during zooming increases, and the aberration is kept low in the entire zoom range from the wide-angle end state to the telephoto end state. It becomes difficult. Moreover, since the movement amount of the first lens group is large, it cannot be reduced in size.
条件式（２）の下限値を下回った場合、第１レンズ群の焦点距離が相対的に短くなるため、広角端状態における第１レンズ群への入射軸外光線と光軸との成す角が小さくなり、広角端状態で７０度を越えた画角を実現しようとすると、第１レンズ群の径が過度に大きくなり小型化できない。また、第１レンズ群で発生する収差が大きくなりすぎて高い光学性能を得ることができない。さらに第２レンズ群の焦点距離が相対的に長くなるため、第２レンズ群が変倍に対し効率的に寄与できなくなり、変倍比が４倍程度以上の高変倍比を確保できない。また、第２レンズ群の移動量が大きくなって小型化できない。 When the lower limit value of conditional expression (2) is not reached, the focal length of the first lens group becomes relatively short, so that the angle formed by the off-axis light beam on the first lens group and the optical axis in the wide-angle end state is If it becomes small and an angle of view exceeding 70 degrees is realized in the wide-angle end state, the diameter of the first lens group becomes excessively large and cannot be reduced in size. In addition, the aberration generated in the first lens group becomes too large to obtain high optical performance. Furthermore, since the focal length of the second lens group becomes relatively long, the second lens group cannot efficiently contribute to zooming, and a zoom ratio of about 4 times or more cannot be secured. In addition, the amount of movement of the second lens group becomes large and cannot be reduced in size.
条件式（３）は、第５レンズ群の最適な焦点距離の範囲を規定するための条件式である。 Conditional expression (3) is a conditional expression for defining the optimum focal length range of the fifth lens group.
条件式（３）の上限値を上回った場合、第５レンズ群の焦点距離は相対的に長くなるため、第５レンズ群は効率的に射出瞳位置を像面から遠くすることができなくなり、固体撮像素子の特性上の要求を満たせない。また、第４レンズ群より物体側のレンズ群で発生する収差を第５レンズ群で十分に補正することが困難となり、高い光学性能を得ることができない。 When the upper limit value of conditional expression (3) is exceeded, the focal length of the fifth lens group becomes relatively long, so the fifth lens group cannot efficiently move the exit pupil position away from the image plane, The characteristics of the solid-state image sensor cannot be satisfied. In addition, it is difficult to sufficiently correct the aberration generated in the lens group closer to the object side than the fourth lens group, and high optical performance cannot be obtained.
条件式（３）の下限値を下回った場合、第５レンズ群の屈折力が相対的に強くなりすぎ、固体撮像素子に適した特性範囲の要求を満たすための射出瞳位置の変動を抑えつつ、広角端状態から望遠端状態までの全域に亘って像面湾曲を補正することが困難となり、高い光学性能を得ることができない。 If the lower limit value of conditional expression (3) is not reached, the refractive power of the fifth lens group becomes relatively strong, while suppressing fluctuations in the exit pupil position to satisfy the requirements of the characteristic range suitable for the solid-state imaging device. Further, it becomes difficult to correct curvature of field over the entire region from the wide-angle end state to the telephoto end state, and high optical performance cannot be obtained.
なお、本発明の効果を確実にする為に、条件式（３）上限値を９．０にすることが好ましい。また、本発明の効果をより確実にする為に、条件式（３）の上限値を８．０にすることがさらに好ましい。また、本発明の効果を確実にする為に、条件式（３）の下限値を４．０にすることが好ましい。 In order to secure the effect of the present invention, it is preferable to set the upper limit of conditional expression (3) to 9.0. In order to further secure the effect of the present invention, it is more preferable to set the upper limit of conditional expression (3) to 8.0. In order to secure the effect of the present invention, it is preferable to set the lower limit of conditional expression (3) to 4.0.
また、本実施の形態にかかるズームレンズは、無限遠合焦状態において、第３レンズ群と第４レンズ群の空気間隔は、光軸に沿って少なくとも広角端状態よりも望遠端状態の方が小さくなることが望ましい。 Further, in the zoom lens according to the present embodiment, in the infinitely focused state, the air interval between the third lens group and the fourth lens group is at least in the telephoto end state along the optical axis in the telephoto end state. It is desirable to make it smaller.
第３レンズ群と第４レンズ群をこのように移動することで、第３レンズ群と第４レンズ群の合成主点位置を広角端状態と望遠端状態との間で大きく移動させることが可能となり、効率的に変倍効果を得ることができる。 By moving the third lens group and the fourth lens group in this way, it is possible to greatly move the combined principal point position of the third lens group and the fourth lens group between the wide-angle end state and the telephoto end state. Thus, a zooming effect can be obtained efficiently.
また、本実施の形態にかかるズームレンズでは、広角端状態から望遠端状態までズーミングする際に、無限遠合焦状態において、第３レンズ群と第４レンズ群との空気間隔は、光軸に沿って減少することが望ましい。 In the zoom lens according to the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the air space between the third lens group and the fourth lens group is in the optical axis in the infinite focus state. It is desirable to decrease along.
第３レンズ群と第４レンズ群をこのように移動することで、第３レンズ群と第４レンズ群の合成主点位置を大きく移動させることが可能となり、効率的に変倍効果を得ることができる。 By moving the third lens group and the fourth lens group in this way, it is possible to largely move the combined principal point position of the third lens group and the fourth lens group, and to efficiently obtain a zooming effect. Can do.
また、本実施の形態にかかるズームレンズでは、広角端状態から望遠端状態までズーミングする際に、無限遠合焦状態において、第５レンズ群は、像面に対して光軸に沿って移動することが望ましい。 In the zoom lens according to the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the fifth lens group moves along the optical axis with respect to the image plane in the infinite focus state. It is desirable.
第５レンズ群をこのように移動することで、効率的な変倍効果を得ることが可能になるばかりでなく、広角端状態から望遠端状態までズーミングする際に第５レンズ群を通る軸外光線の通る位置を最適化することが可能となり、軸外収差をズーム全域に亘って補正することができ、高い光学性能を得ることができる。 By moving the fifth lens group in this way, not only can an efficient zooming effect be obtained, but also off-axis passing through the fifth lens group when zooming from the wide-angle end state to the telephoto end state. It is possible to optimize the position through which the light passes, and off-axis aberrations can be corrected over the entire zoom range, so that high optical performance can be obtained.
また、本実施の形態にかかるズームレンズでは、無限遠合焦状態において、第５レンズ群は、光軸に沿って少なくとも広角端状態よりも望遠端状態の方が物体側にあることが望ましい。 In the zoom lens according to the present embodiment, in the infinitely focused state, it is desirable that the fifth lens group is at the telephoto end state at least on the object side along the optical axis rather than at the wide-angle end state.
本実施の形態では、広角端状態から望遠端状態へのズーミングに際し、効率的な変倍を行うために第４レンズ群と第５レンズ群の間隔が増大している。すると、広角端状態に比べ望遠端状態の方が第５レンズ群を通る軸外光線の光軸からの高さが高くなるため、第５レンズ群の正屈折力のためにレンズ系全体の射出瞳位置が像面に対して急激に遠くなって、射出瞳位置の変動が大きくなって固体撮像素子の特性上の要求を満たすことが難しくなる。そこで、第５レンズ群をこのように構成することで、射出瞳位置の変動を小さくでき固体撮像素子の特性上の要求を満たすことができる。 In the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the distance between the fourth lens group and the fifth lens group is increased in order to perform efficient zooming. Then, since the height from the optical axis of the off-axis light beam passing through the fifth lens group is higher in the telephoto end state than in the wide-angle end state, the entire lens system is emitted due to the positive refractive power of the fifth lens group. As the pupil position becomes abruptly far from the image plane, the variation of the exit pupil position becomes large, and it becomes difficult to satisfy the requirements on the characteristics of the solid-state imaging device. Therefore, by configuring the fifth lens group in this way, the variation of the exit pupil position can be reduced and the requirements on the characteristics of the solid-state imaging device can be satisfied.
また、本実施の形態にかかるズームレンズでは、第３レンズ群は光軸に沿って物体側から順に、正屈折力を有する第３ａレンズ群と、開口絞りと、第３ｂレンズ群とを有することが望ましい。 In the zoom lens according to the present embodiment, the third lens group includes, in order from the object side along the optical axis, a third lens group having positive refractive power, an aperture stop, and a third lens group. Is desirable.
本発明のズームレンズでは、第３レンズ群は変倍への寄与が大きく、ズームレンズ全体の収差補正上重要な役割を持っていおり、正屈折力を有する第３ａレンズ群と第３ｂレンズ群が開口絞りを挟む構成とすることで、軸上収差を効率的に補正することが可能となり、高い光学性能を得ることができる。 In the zoom lens of the present invention, the third lens group greatly contributes to zooming, and has an important role in correcting aberrations of the entire zoom lens. The third a lens group and the third b lens group having positive refractive power are By adopting a configuration in which the aperture stop is sandwiched, it is possible to efficiently correct axial aberrations and to obtain high optical performance.
また、本実施の形態にかかるズームレンズでは、光軸に沿って物体側から順に、第３ａレンズ群は負屈折力を有するレンズと正屈折力を有するレンズから成る接合レンズのみで構成され、前記第３ｂレンズ群は正屈折力を有するレンズと負屈折力を有するレンズから成る接合レンズのみで構成されることが望ましい。 In the zoom lens according to the present embodiment, in order from the object side along the optical axis, the 3a lens group includes only a cemented lens including a lens having negative refractive power and a lens having positive refractive power, It is desirable that the third lens group is constituted only by a cemented lens including a lens having a positive refractive power and a lens having a negative refractive power.
開口絞りの物体側の第３ａレンズ群と、開口絞りの像側の第３ｂレンズ群をこのような構成とすることで、開口絞りを挟んだ所謂対称型の構成となって軸上収差を効果的に補正できるため、ズームレンズ全体として収差補正が良好にでき、高い光学性能を得ることができる。 By configuring the 3a lens group on the object side of the aperture stop and the 3b lens group on the image side of the aperture stop in such a configuration, a so-called symmetrical configuration with the aperture stop interposed therebetween is effective for axial aberration. Therefore, the zoom lens as a whole can be corrected favorably and high optical performance can be obtained.
また、本実施の形態にかかるズームレンズでは、以下の条件式（４）を満足することが望ましい。
（４）−０．５０＜ｆ３ａ／ｆ３ｂ＜０．８０
但し、ｆ３ａは第３ａレンズ群の焦点距離、ｆ３ｂは第３ｂレンズ群の焦点距離を表す。
In the zoom lens according to the present embodiment, it is preferable that the following conditional expression (4) is satisfied.
(4) -0.50 <f3a / f3b <0.80
However, f3a represents the focal length of the 3a lens group, and f3b represents the focal length of the 3b lens group.
条件式（４）は、第３ａレンズ群の焦点距離と第３ｂレンズ群の焦点距離の最適な比を規定するための条件式である。 Conditional expression (4) is a conditional expression for defining an optimum ratio of the focal length of the 3a lens group and the focal length of the 3b lens group.
条件式（４）の上限値を上回った場合、第３ａレンズ群の屈折力に対して第３ｂレンズ群の屈折力が相対的に強くなるため、第３ｂレンズ群の像側にある正屈折力の第４レンズ群と合わせると、開口絞りの像側の正屈折力が物体側の正屈折力より強くなりすぎて軸外収差の補正が困難となり、高い光学性能を得ることができない。 When the upper limit of conditional expression (4) is exceeded, the refractive power of the 3b lens group becomes relatively stronger than the refractive power of the 3a lens group, so that the positive refractive power on the image side of the 3b lens group is increased. In combination with the fourth lens group, the positive refracting power on the image side of the aperture stop becomes too stronger than the positive refracting power on the object side, making it difficult to correct off-axis aberrations, and high optical performance cannot be obtained.
条件式（４）の下限値を下回った場合、第３レンズ群全体の屈折力が弱くなるため変倍に効率的に寄与できなくなり、４倍程度以上の高変倍比を確保できない。また、第３レンズ群の移動量が大きくなることによって広角端状態から望遠端状態までの全ズーム範囲において収差を低く抑えることが困難となる。また、第３レンズ群の移動量が大きいために小型化できない。 If the lower limit value of conditional expression (4) is not reached, the refractive power of the entire third lens group becomes weak, so that it cannot contribute efficiently to zooming, and a high zoom ratio of about 4 times or more cannot be secured. Further, since the movement amount of the third lens group is increased, it is difficult to suppress aberrations in the entire zoom range from the wide-angle end state to the telephoto end state. Moreover, since the movement amount of the third lens group is large, the size cannot be reduced.
なお、本発明の効果を確実にする為に、条件式（４）の上限値を０．７０とすることが好ましい。また、本発明の効果を確実にするために、条件式（４）の下限値を０．００とすることが好ましい。また、本発明の効果をさらに確実にするために、条件式（４）の下限値を０．３８とすることがさらに好ましい。 In order to secure the effect of the present invention, it is preferable to set the upper limit of conditional expression (4) to 0.70. In order to secure the effect of the present invention, it is preferable to set the lower limit of conditional expression (4) to 0.00. In order to further secure the effect of the present invention, it is more preferable to set the lower limit of conditional expression (4) to 0.38.
また、本実施の形態にかかるズームレンズでは、第２レンズ群は非球面レンズを含むことが望ましい。 In the zoom lens according to the present embodiment, it is desirable that the second lens group includes an aspheric lens.
第２レンズ群に非球面レンズを含むことで、第２レンズ群で発生する軸外収差を効率的に補正できるため、高い光学性能を得ることができる。 By including an aspherical lens in the second lens group, off-axis aberrations generated in the second lens group can be corrected efficiently, so that high optical performance can be obtained.
また、本実施の形態にかかるズームレンズでは、第４レンズ群は非球面レンズを含むことが望ましい。 In the zoom lens according to the present embodiment, it is desirable that the fourth lens group includes an aspheric lens.
第４レンズ群に非球面レンズを含むことで、第４レンズ群で発生する球面収差を効率的に補正することできるため、高い光学性能を得ることができる。 By including an aspheric lens in the fourth lens group, it is possible to efficiently correct the spherical aberration generated in the fourth lens group, so that high optical performance can be obtained.
（実施例）
以下に、本発明の実施の形態にかかる各実施例について添付図面に基づいて説明する。なお、各実施例において非球面は以下の式で表される。
ｘ＝ｃｙ２／｛１＋（１−κｃ２ｙ２）１／２｝
＋Ｃ4ｙ４＋Ｃ6ｙ６＋Ｃ8ｙ８＋Ｃ10ｙ１０
なお、ｙは光軸からの高さ、ｘはサグ量、ｃは基準曲率（頂点曲率）で曲率は曲率半径の逆数、κは円錐定数、Ｃ4，Ｃ6，Ｃ8，Ｃ10は非球面係数である。また、｛Ｅｎ｝は｛×１０ｎ｝を表す。
(Example)
Embodiments according to embodiments of the present invention will be described below with reference to the accompanying drawings. In each embodiment, the aspherical surface is expressed by the following equation.
x = cy 2 / {1+ (1-κc 2 y 2 ) 1/2 }
+ C4y 4 + C6y 6 + C8y 8 + C10y 10
Here, y is the height from the optical axis, x is the sag amount, c is the reference curvature (vertical curvature), the curvature is the reciprocal of the radius of curvature, κ is the conic constant, and C4, C6, C8 and C10 are aspheric coefficients. . {En} represents {× 10 n }.
［第１実施例］
図１は、本発明の第１実施例にかかるズームレンズの無限遠合焦状態でのレンズ構成の断面図を示し、（Ｗ）は広角端状態を、（Ｍ）は中間焦点距離状態を、（Ｔ）は望遠端状態をそれぞれ示す。
[First embodiment]
FIG. 1 is a cross-sectional view of a lens configuration of a zoom lens according to a first embodiment of the present invention in an infinitely focused state, where (W) is a wide-angle end state, (M) is an intermediate focal length state, (T) indicates the telephoto end state.
図１において、本第１実施例にかかるズームレンズは、光軸に沿って物体側から順に、正屈折力を有する第１レンズ群Ｇ１と、負屈折力を有する第２レンズ群Ｇ２と、正屈折力を有する第３レンズ群Ｇ３と、正屈折力を有する第４レンズ群Ｇ４と、正屈折力を有する第５レンズ群Ｇ５とから構成され、広角端状態Ｗから望遠端状態Ｔまでズーミングする際に、無限遠合焦状態において、第１レンズ群Ｇ１と第２レンズ群Ｇ２との空気間隔は増加し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との空気間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との空気間隔は変化しながら減少し、第４レンズ群Ｇ４と第５レンズ群Ｇ５との空気間隔は増加するように、第１レンズ群Ｇ１は像面Ｉに対して移動し、第２レンズ群Ｇ２は像面Ｉ側に移動した後、物体側に移動するような軌跡で移動し、第３レンズ群Ｇ３は物体側に移動し、第４レンズ群Ｇ４は物体側に移動し、第５レンズ群Ｇ５は像面Ｉに対して移動し広角端状態Ｗよりも望遠端状態Ｔの方が物体側にある。 In FIG. 1, the zoom lens according to the first example includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens in order from the object side along the optical axis. A third lens group G3 having a refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are zoomed from the wide-angle end state W to the telephoto end state T. In the infinite focus state, the air gap between the first lens group G1 and the second lens group G2 increases, the air gap between the second lens group G2 and the third lens group G3 decreases, and the third The first lens group G1 has an image plane I such that the air gap between the lens group G3 and the fourth lens group G4 decreases while changing, and the air gap between the fourth lens group G4 and the fifth lens group G5 increases. The second lens group G2 has moved to the image plane I side. The third lens group G3 moves to the object side, the fourth lens group G4 moves to the object side, and the fifth lens group G5 moves relative to the image plane I. The telephoto end state T is closer to the object side than the wide-angle end state W.
第１レンズ群Ｇ１は、光軸に沿って物体側から順に、物体側に凸面を向けた負メニスカスレンズと物体側に凸面を向けた正メニスカスレンズとの接合レンズと、物体側に凸面を向けた正メニスカスレンズとから構成され、全体として正屈折力を有している。 The first lens group G1 includes, in order from the object side along the optical axis, a cemented lens of a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side, and the convex surface facing the object side. The positive meniscus lens has a positive refractive power as a whole.
第２レンズ群Ｇ２は、光軸に沿って物体側から順に、像側の面が非球面の負メニスカスレンズと、像側の面の曲率が強い両凹形状の負レンズと、物体側に凸面を向けた正メニスカスレンズとから構成され、全体として負屈折力を有している。 The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens having an aspheric image side surface, a biconcave negative lens having a strong curvature on the image side surface, and a convex surface on the object side. And a negative meniscus lens as a whole.
第３レンズ群Ｇ３は、光軸に沿って物体側から順に、第３ａレンズ群Ｇ３ａと開口絞りＳと第３ｂレンズ群Ｇ３ｂとから構成され、第３ａレンズ群Ｇ３ａは物体側に凸面を向けた負メニスカスレンズと物体側の面の曲率が強い両凸形状の正レンズとの接合レンズで構成され全体として正屈折力を有し、第３ｂレンズ群Ｇ３ｂはほぼ同曲率面の両凸形状の正レンズと物体側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され全体として正屈折力を有している。 The third lens group G3 is composed of a 3a lens group G3a, an aperture stop S, and a 3b lens group G3b in order from the object side along the optical axis. The 3a lens group G3a has a convex surface directed toward the object side. It consists of a cemented lens of a negative meniscus lens and a biconvex positive lens with a strong curvature on the object side surface, and has positive refractive power as a whole, and the third lens group G3b has a biconvex positive shape with substantially the same curvature surface. The lens has a positive refractive power as a whole, and is composed of a cemented lens formed by a lens and a biconcave negative lens having a strong curvature on the object side surface.
第４レンズ群Ｇ４は、光軸に沿って物体側から順に、物体側の面が非球面の両凸形状の正レンズと、像側に凸面を向けた正メニスカスレンズと物体側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され、全体として正屈折力を有している。 The fourth lens group G4 includes, in order from the object side along the optical axis, a biconvex positive lens having an aspheric object side surface, a positive meniscus lens having a convex surface directed to the image side, and the curvature of the object side surface. Is composed of a cemented lens with a strong biconcave negative lens, and has a positive refractive power as a whole.
第５レンズ群Ｇ５は、物体側に凸面を向けた正メニスカスレンズで構成され、全体として正屈折力を有している。 The fifth lens group G5 includes a positive meniscus lens having a convex surface directed toward the object side, and has a positive refracting power as a whole.
第５レンズ群Ｇ５の像側には、固体撮像素子の略ナイキスト周波数以上の解像力をカットするための光学ローパスフィルタＯＬＰＦが配置され、その像側には、撮像素子表面を保護するためのカバーガラスＣＧが配置されている。 On the image side of the fifth lens group G5, an optical low-pass filter OLPF for cutting the resolving power equal to or higher than the substantially Nyquist frequency of the solid-state image sensor is disposed, and on the image side, a cover glass for protecting the image sensor surface. CG is arranged.
以下の表１に本第１実施例にかかるズームレンズの諸元の値を掲げる。表中、[全体諸元]のｆはレンズ系全体の焦点距離（ｍｍ）、ＦＮｏはＦナンバー、２ωは画角（単位：度）、ＴＬは全長（ｍｍ）で最も物体側のレンズ面から像面までの距離をそれぞれ表す。[レンズデータ]のｎｄはｄ線（λ＝５８７．６ｎｍ）における屈折率、νはｄ線（λ＝５８７．６ｎｍ）におけるアッベ数、(Bf)はバックフォーカスをそれぞれ表す。なお、空気の屈折率１．０００００は記載を省略し、曲率半径の「∞」は平面を表す。[可変間隔データ]には、焦点距離ｆと、可変間隔の値をそれぞれ示す。[条件式対応値]には、各条件式の値をそれぞれ示す。 Table 1 below shows values of specifications of the zoom lens according to the first example. In the table, f in [Whole specifications] is the focal length (mm) of the entire lens system, FNo is the F number, 2ω is the angle of view (unit: degree), and TL is the total length (mm) from the lens surface closest to the object side. Represents the distance to the image plane. In [lens data], nd represents the refractive index at the d-line (λ = 587.6 nm), ν represents the Abbe number at the d-line (λ = 587.6 nm), and (Bf) represents the back focus. Note that the refractive index of air of 1.0000 is omitted, and the curvature radius “∞” represents a plane. [Variable interval data] indicates the focal length f and the value of the variable interval. [Conditional Expression Corresponding Value] indicates the value of each conditional expression.
なお、以下の全ての諸元値において、掲載されている焦点距離ｆ、曲率半径、面間隔その他の長さ等は、特記の無い場合一般に「ｍｍ」が使われるが、光学系は比例拡大または比例縮小しても同等の光学性能が得られるので、これに限られるものではない。また、単位は「ｍｍ」に限定されること無く他の適当な単位を用いることもできる。さらに、これらの記号の説明は、以降の他の実施例においても同様とする。 In addition, in all the following specification values, “mm” is generally used as the focal length f, the radius of curvature, the surface interval and other lengths, etc. unless otherwise specified. Even if proportional reduction is performed, the same optical performance can be obtained. Further, the unit is not limited to “mm”, and other appropriate units may be used. Furthermore, the description of these symbols is the same in the other examples.
（表１）
［全体諸元］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 7.30 24.00 48.70
ＦＮｏ 2.9 3.9 4.8
２ω 76.8 25.7 12.8
ＴＬ 93.8 103.0 114.0
[レンズデータ]
面番号 曲率半径 面間隔 ｎｄ ν
1 57.0839 1.2000 1.85026 32.35
2 31.9927 8.2500 1.49782 82.52
3 229.0922 0.1000
4 32.5008 5.5000 1.62041 60.29
5 180.7580 (D5)
6 348.6512 2.2500 1.79668 45.37
7 8.4204 6.7600
8 -22.6529 0.9000 1.51633 64.14
9 13.9142 0.3000
10 14.8081 3.2000 1.84666 23.78
11 137.4384 (D11)
12 35.9124 0.9000 1.80100 34.96
13 18.8088 2.5000 1.49782 82.52
14 -31.7991 1.2000
15 ∞ 1.2000 (開口絞りＳ)
16 10.4440 3.6000 1.60562 43.73
17 -10.6282 1.8000 1.72342 37.95
18 15.3008 (D18)
19 40.4812 2.8500 1.79668 45.37
20 -12.7297 0.2000
21 -37.4296 3.0000 1.49782 82.52
22 -8.1540 1.0000 1.80100 34.96
23 63.9580 (D23)
24 19.8524 2.6000 1.51633 64.14
25 1344.6027 (D25)
26 ∞ 2.7600 1.51680 64.20 (OLPF)
27 ∞ 1.4410
28 ∞ 0.5000 1.51680 64.20 (CG)
29 ∞ (Bf)
［非球面データ］
面番号 κ Ｃ4 Ｃ6 Ｃ8 Ｃ10
7 0.7000 1.0988E-06 -7.2334E-07 1.1607E-08 -1.2470E-10
19 1.0000 -1.0498E-04 -4.3631E-07 1.7227E-08 -4.4410E-10
［可変間隔データ］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 7.30 24.00 48.70
D5 1.8000 17.8458 25.5276
D11 24.6785 8.2615 3.2000
D18 3.3239 1.5579 1.5000
D23 6.3759 15.2556 24.6538
D25 2.6222 5.0974 4.1067
［条件式対応値］
（１）ｆ１／ｆＷ＝７．９３
（２）ｆ１／（−ｆ２）＝５．９９
（３）ｆ５／ｆＷ＝５．３４
（４）ｆ３ａ／ｆ３ｂ＝０．４４３
(Table 1)
[Overall specifications]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 7.30 24.00 48.70
FNo 2.9 3.9 4.8
2ω 76.8 25.7 12.8
TL 93.8 103.0 114.0
[Lens data]
Surface number Curvature radius Surface spacing nd ν
1 57.0839 1.2000 1.85026 32.35
2 31.9927 8.2500 1.49782 82.52
3 229.0922 0.1000
4 32.5008 5.5000 1.62041 60.29
5 180.7580 (D5)
6 348.6512 2.2500 1.79668 45.37
7 8.4204 6.7600
8 -22.6529 0.9000 1.51633 64.14
9 13.9142 0.3000
10 14.8081 3.2000 1.84666 23.78
11 137.4384 (D11)
12 35.9124 0.9000 1.80100 34.96
13 18.8088 2.5000 1.49782 82.52
14 -31.7991 1.2000
15 ∞ 1.2000 (Aperture stop S)
16 10.4440 3.6000 1.60562 43.73
17 -10.6282 1.8000 1.72342 37.95
18 15.3008 (D18)
19 40.4812 2.8500 1.79668 45.37
20 -12.7297 0.2000
21 -37.4296 3.0000 1.49782 82.52
22 -8.1540 1.0000 1.80100 34.96
23 63.9580 (D23)
24 19.8524 2.6000 1.51633 64.14
25 1344.6027 (D25)
26 ∞ 2.7600 1.51680 64.20 (OLPF)
27 ∞ 1.4410
28 ∞ 0.5000 1.51680 64.20 (CG)
29 ∞ (Bf)
[Aspherical data]
Surface number κ C4 C6 C8 C10
7 0.7000 1.0988E-06 -7.2334E-07 1.1607E-08 -1.2470E-10
19 1.0000 -1.0498E-04 -4.3631E-07 1.7227E-08 -4.4410E-10
[Variable interval data]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 7.30 24.00 48.70
D5 1.8000 17.8458 25.5276
D11 24.6785 8.2615 3.2000
D18 3.3239 1.5579 1.5000
D23 6.3759 15.2556 24.6538
D25 2.6222 5.0974 4.1067
[Conditional expression values]
(1) f1 / fW = 7.93
(2) f1 / (− f2) = 5.99
(3) f5 / fW = 5.34
(4) f3a / f3b = 0.443
図２は、本発明の第１実施例にかかるズームレンズのｄ線（λ＝５８７．６ｎｍ）に対する諸収差図を表し、（ａ）は広角端状態（Ｗ）を、（ｂ）は中間焦点距離状態（Ｍ）を、（ｃ）は望遠端状態（Ｔ）をそれぞれ表す。収差図において、ＦＮｏはＦナンバー、Ａは光線入射角（単位：度）を、非点収差図中の実線はサジタル像面、破線はメリディオナル像面を示し、コマ収差図は各光線入射角Ａでのコマ収差を表す。なお、これらの記号は以降の他の実施例においても同様とする。 2A and 2B are graphs showing various aberrations with respect to the d-line (λ = 587.6 nm) of the zoom lens according to Example 1 of the present invention. FIG. 2A shows the wide-angle end state (W), and FIG. 2B shows the intermediate focus. The distance state (M) and (c) represent the telephoto end state (T), respectively. In the aberration diagrams, FNo is the F number, A is the ray incident angle (unit: degree), the solid line in the astigmatism diagram is the sagittal image plane, the broken line is the meridional image plane, and the coma aberration diagram is for each ray incident angle A. Represents the coma aberration at. Note that these symbols are the same in other examples.
各収差図から、本第１実施例にかかるズームレンズは高い光学性能を有していることが明らかである。また、ズームレンズ全長が９３．８ｍｍ〜１１４．０ｍｍと小型であることが明らかである。 From each aberration diagram, it is clear that the zoom lens according to the first example has high optical performance. In addition, it is clear that the total length of the zoom lens is as small as 93.8 mm to 114.0 mm.
［第２実施例］
図３は、本発明の第２実施例にかかるズームレンズの無限遠合焦状態でのレンズ構成の断面図を示し、（Ｗ）は広角端状態を、（Ｍ）は中間焦点距離状態を、（Ｔ）は望遠端状態をそれぞれ示す。
[Second Embodiment]
FIG. 3 is a sectional view of the lens configuration of the zoom lens according to the second embodiment of the present invention in an infinitely focused state, where (W) is a wide-angle end state, (M) is an intermediate focal length state, (T) indicates the telephoto end state.
図３において、本第２実施例にかかるズームレンズは、光軸に沿って物体側から順に、正屈折力を有する第１レンズ群Ｇ１と、負屈折力を有する第２レンズ群Ｇ２と、正屈折力を有する第３レンズ群Ｇ３と、正屈折力を有する第４レンズ群Ｇ４と、正屈折力を有する第５レンズ群Ｇ５とから構成され、広角端状態Ｗから望遠端状態Ｔまでズーミングする際に、無限遠合焦状態において、第１レンズ群Ｇ１と第２レンズ群Ｇ２との空気間隔は増加し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との空気間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との空気間隔は変化しながら減少し、第４レンズ群Ｇ４と第５レンズ群Ｇ５との空気間隔は増加するように、第１レンズ群Ｇ１は像面Ｉに対して移動し、第２レンズ群Ｇ２は像面Ｉ側に移動した後、物体側に移動するような軌跡で移動し、第３レンズ群Ｇ３は物体側に移動し、第４レンズ群Ｇ４は物体側に移動し、第５レンズ群Ｇ５は像面Ｉに対して移動し広角端状態Ｗよりも望遠端状態Ｔの方が物体側にある。 In FIG. 3, the zoom lens according to the second example includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens in order from the object side along the optical axis. A third lens group G3 having a refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are zoomed from the wide-angle end state W to the telephoto end state T. In the infinite focus state, the air gap between the first lens group G1 and the second lens group G2 increases, the air gap between the second lens group G2 and the third lens group G3 decreases, and the third The first lens group G1 has an image plane I such that the air gap between the lens group G3 and the fourth lens group G4 decreases while changing, and the air gap between the fourth lens group G4 and the fifth lens group G5 increases. The second lens group G2 has moved to the image plane I side. The third lens group G3 moves to the object side, the fourth lens group G4 moves to the object side, and the fifth lens group G5 moves relative to the image plane I. The telephoto end state T is closer to the object side than the wide-angle end state W.
第１レンズ群Ｇ１は、光軸に沿って物体側から順に、物体側に凸面を向けた負メニスカスレンズと物体側に凸面を向けた正メニスカスレンズとの接合レンズと、物体側に凸面を向けた正メニスカスレンズとから構成され、全体として正屈折力を有している。 The first lens group G1 includes, in order from the object side along the optical axis, a cemented lens of a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side, and the convex surface facing the object side. The positive meniscus lens has a positive refractive power as a whole.
第２レンズ群Ｇ２は、光軸に沿って物体側から順に、像側の面が非球面の負メニスカスレンズと、像側の面の曲率が強い両凹形状の負レンズと、物体側の面の曲率が強い両凸形状の正レンズと物体側の曲率が強い両凹形状の負レンズとの接合レンズとから構成され、全体として負屈折力を有している。 The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens having an aspheric image side surface, a biconcave negative lens having a strong curvature on the image side surface, and an object side surface. And a cemented lens composed of a biconvex positive lens having a strong curvature and a biconcave negative lens having a strong curvature on the object side, and has a negative refracting power as a whole.
第３レンズ群Ｇ３は、光軸に沿って物体側から順に、第３ａレンズ群Ｇ３ａと開口絞りＳと第３ｂレンズ群Ｇ３ｂとから構成され、第３ａレンズ群Ｇ３ａは物体側に凸面を向けた負メニスカスレンズと物体側の面の曲率が強い両凸形状の正レンズとの接合レンズで構成され全体として正屈折力を有し、第３ｂレンズ群Ｇ３ｂはほぼ同曲率面の両凸形状の正レンズと物体側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され全体として正屈折力を有している。 The third lens group G3 is composed of a 3a lens group G3a, an aperture stop S, and a 3b lens group G3b in order from the object side along the optical axis. The 3a lens group G3a has a convex surface directed toward the object side. It consists of a cemented lens of a negative meniscus lens and a biconvex positive lens with a strong curvature on the object side surface, and has positive refractive power as a whole, and the third lens group G3b has a biconvex positive shape with substantially the same curvature surface. The lens has a positive refractive power as a whole, and is composed of a cemented lens formed by a lens and a biconcave negative lens having a strong curvature on the object side surface.
第４レンズ群Ｇ４は、光軸に沿って物体側から順に、物体側の面が非球面の両凸形状の正レンズと、像側の面の曲率が強い両凸形状の正レンズと物体側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され、全体として正屈折力を有している。 The fourth lens group G4 includes, in order from the object side along the optical axis, a biconvex positive lens having an aspheric object side surface, a biconvex positive lens having a strong curvature on the image side surface, and an object side. And has a positive refracting power as a whole.
第５レンズ群Ｇ５は、物体側に凸面を向けた正メニスカスレンズで構成され、全体として正屈折力を有している。 The fifth lens group G5 includes a positive meniscus lens having a convex surface directed toward the object side, and has a positive refracting power as a whole.
第５レンズ群Ｇ５の像側には、固体撮像素子の略ナイキスト周波数以上の解像力をカットするための光学ローパスフィルタＯＬＰＦが配置され、その像側には、撮像素子表面を保護するためのカバーガラスＣＧが配置されている。 On the image side of the fifth lens group G5, an optical low-pass filter OLPF for cutting the resolving power equal to or higher than the substantially Nyquist frequency of the solid-state image sensor is disposed, and on the image side, a cover glass for protecting the image sensor surface. CG is arranged.
以下の表２に本第２実施例にかかるズームレンズの諸元の値を掲げる。 Table 2 below provides values of specifications of the zoom lens according to the second example.
（表２）
［全体諸元］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 7.30 24.00 48.70
ＦＮｏ 2.9 4.0 5.0
２ω 76.2 25.3 12.7
ＴＬ 89.4 103.2 117.0
[レンズデータ]
面番号 曲率半径 面間隔 ｎｄ ν
1 68.7733 1.2000 1.84666 23.78
2 44.6048 6.0000 1.62041 60.29
3 502.6841 0.1000
4 39.2284 4.5500 1.49700 81.61
5 179.0209 (D5)
6 231.9477 2.2500 1.79668 45.37
7 8.1352 6.4000
8 -24.3449 0.9000 1.62041 60.29
9 19.8092 0.1000
10 16.7821 3.4000 1.84666 23.78
11 -112.6407 0.9000 1.67790 55.34
12 129.3558 (D12)
13 45.0022 0.9000 1.80100 34.96
14 22.0792 2.5000 1.49782 82.52
15 -27.9147 1.2000
16 ∞ 1.5000 (開口絞りＳ)
17 11.6350 3.7000 1.60738 56.82
18 -11.2356 1.6000 1.71700 47.93
19 19.1180 (D19)
20 42.2272 3.5000 1.67790 54.89
21 -13.6179 0.1000
22 104.8201 2.6000 1.48749 70.24
23 -18.2010 1.0000 1.80100 34.96
24 23.5017 (D24)
25 16.0661 2.5000 1.48749 70.24
26 53.8612 (D26)
27 ∞ 1.7200 1.51680 64.20 (OLPF)
28 ∞ 1.4410
29 ∞ 0.5000 1.51680 64.20 (CG)
30 ∞ (Bf)
［非球面データ］
面番号 κ Ｃ4 Ｃ6 Ｃ8 Ｃ10
7 0.8300 -1.1807E-05 -2.8221E-07 9.6728E-10 -3.6526E-11
20 1.0000 -1.6050E-04 -4.4980E-07 1.2616E-08 -3.1336E-10
［可変間隔データ］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 7.30 24.00 48.70
D5 2.2068 19.9136 28.5702
D12 21.2565 6.7047 2.4000
D19 4.4227 2.0462 1.6990
D24 5.4752 16.2164 27.1884
D26 4.5105 6.7630 5.5814
［条件式対応値］
（１）ｆ１／ｆＷ＝８．６８
（２）ｆ１／（−ｆ２）＝６．９２
（３）ｆ５／ｆＷ＝６．３０
（４）ｆ３ａ／ｆ３ｂ＝０．５５９
(Table 2)
[Overall specifications]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 7.30 24.00 48.70
FNo 2.9 4.0 5.0
2ω 76.2 25.3 12.7
TL 89.4 103.2 117.0
[Lens data]
Surface number Curvature radius Surface spacing nd ν
1 68.7733 1.2000 1.84666 23.78
2 44.6048 6.0000 1.62041 60.29
3 502.6841 0.1000
4 39.2284 4.5500 1.49700 81.61
5 179.0209 (D5)
6 231.9477 2.2500 1.79668 45.37
7 8.1352 6.4000
8 -24.3449 0.9000 1.62041 60.29
9 19.8092 0.1000
10 16.7821 3.4000 1.84666 23.78
11 -112.6407 0.9000 1.67790 55.34
12 129.3558 (D12)
13 45.0022 0.9000 1.80 100 34.96
14 22.0792 2.5000 1.49782 82.52
15 -27.9147 1.2000
16 ∞ 1.5000 (Aperture stop S)
17 11.6350 3.7000 1.60738 56.82
18 -11.2356 1.6000 1.71700 47.93
19 19.1180 (D19)
20 42.2272 3.5000 1.67790 54.89
21 -13.6179 0.1000
22 104.8201 2.6000 1.48749 70.24
23 -18.2010 1.0000 1.80100 34.96
24 23.5017 (D24)
25 16.0661 2.5000 1.48749 70.24
26 53.8612 (D26)
27 ∞ 1.7200 1.51680 64.20 (OLPF)
28 ∞ 1.4410
29 ∞ 0.5000 1.51680 64.20 (CG)
30 ∞ (Bf)
[Aspherical data]
Surface number κ C4 C6 C8 C10
7 0.8300 -1.1807E-05 -2.8221E-07 9.6728E-10 -3.6526E-11
20 1.0000 -1.6050E-04 -4.4980E-07 1.2616E-08 -3.1336E-10
[Variable interval data]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 7.30 24.00 48.70
D5 2.2068 19.9136 28.5702
D12 21.2565 6.7047 2.4000
D19 4.4227 2.0462 1.6990
D24 5.4752 16.2164 27.1884
D26 4.5105 6.7630 5.5814
[Conditional expression values]
(1) f1 / fW = 8.68
(2) f1 / (− f2) = 6.92
(3) f5 / fW = 6.30
(4) f3a / f3b = 0.559
図４は、本発明の第２実施例にかかるズームレンズのｄ線（λ＝５８７．６ｎｍ）に対する諸収差図を表し、（ａ）は広角端状態（Ｗ）を、（ｂ）は中間焦点距離状態（Ｍ）を、（ｃ）は望遠端状態（Ｔ）をそれぞれ表す。 4A and 4B are graphs showing various aberrations with respect to the d-line (λ = 587.6 nm) of the zoom lens according to the second example of the present invention. FIG. 4A shows the wide-angle end state (W), and FIG. The distance state (M) and (c) represent the telephoto end state (T), respectively.
各収差図から、本第２実施例にかかるズームレンズは高い光学性能を有していることが明らかである。また、ズームレンズ全長が８９．４ｍｍ〜１１７．０ｍｍと小型であることが明らかである。 From each aberration diagram, it is clear that the zoom lens according to the second example has high optical performance. In addition, it is clear that the total length of the zoom lens is as small as 89.4 mm to 117.0 mm.
［第３実施例］
図５は、本発明の第３実施例にかかるズームレンズの無限遠合焦状態でのレンズ構成の断面図を示し、（Ｗ）は広角端状態を、（Ｍ）は中間焦点距離状態を、（Ｔ）は望遠端状態をそれぞれ示す。
[Third embodiment]
FIG. 5 is a cross-sectional view of the lens configuration of the zoom lens according to the third embodiment of the present invention in the infinitely focused state, (W) is the wide-angle end state, (M) is the intermediate focal length state, (T) indicates the telephoto end state.
図５において、本第３実施例にかかるズームレンズは、光軸に沿って物体側から順に、正屈折力を有する第１レンズ群Ｇ１と、負屈折力を有する第２レンズ群Ｇ２と、正屈折力を有する第３レンズ群Ｇ３と、正屈折力を有する第４レンズ群Ｇ４と、正屈折力を有する第５レンズ群Ｇ５とから構成され、広角端状態Ｗから望遠端状態Ｔまでズーミングする際に、無限遠合焦状態において、第１レンズ群Ｇ１と第２レンズ群Ｇ２との空気間隔は増加し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との空気間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との空気間隔は変化しながら減少し、第４レンズ群Ｇ４と第５レンズ群Ｇ５との空気間隔は増加するように、第１レンズ群Ｇ１は像面Ｉに対して移動し、第２レンズ群Ｇ２は像面Ｉ側に移動した後、物体側に移動するような軌跡で移動し、第３レンズ群Ｇ３は物体側に移動し、第４レンズ群Ｇ４は物体側に移動し、第５レンズ群Ｇ５は像面Ｉに対して移動し広角端状態Ｗよりも望遠端状態Ｔの方が物体側にある。 In FIG. 5, the zoom lens according to the third example includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens in order from the object side along the optical axis. A third lens group G3 having a refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are zoomed from the wide-angle end state W to the telephoto end state T. In the infinite focus state, the air gap between the first lens group G1 and the second lens group G2 increases, the air gap between the second lens group G2 and the third lens group G3 decreases, and the third The first lens group G1 has an image plane I such that the air gap between the lens group G3 and the fourth lens group G4 decreases while changing, and the air gap between the fourth lens group G4 and the fifth lens group G5 increases. The second lens group G2 has moved to the image plane I side. The third lens group G3 moves to the object side, the fourth lens group G4 moves to the object side, and the fifth lens group G5 moves relative to the image plane I. The telephoto end state T is closer to the object side than the wide-angle end state W.
第１レンズ群Ｇ１は、光軸に沿って物体側から順に、物体側に凸面を向けた負メニスカスレンズと物体側に凸面を向けた正メニスカスレンズとの接合レンズと、物体側に凸面を向けた正メニスカスレンズとから構成され、全体として正屈折力を有している。 The first lens group G1 includes, in order from the object side along the optical axis, a cemented lens of a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side, and the convex surface facing the object side. The positive meniscus lens has a positive refractive power as a whole.
第２レンズ群Ｇ２は、光軸に沿って物体側から順に、像側の面が非球面の負メニスカスレンズと、像側の面の曲率が強い両凹形状の負レンズと物体側に凸面を向けた正メニスカスレンズとの接合レンズと、物体側の面の曲率が強い両凸形状の正レンズとから構成され、全体として負屈折力を有している。 The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens having an aspheric image side surface, a biconcave negative lens having a strong curvature on the image side surface, and a convex surface on the object side. It is composed of a cemented lens with a directed positive meniscus lens and a biconvex positive lens with a strong curvature on the object side surface, and has a negative refractive power as a whole.
第３レンズ群Ｇ３は、光軸に沿って物体側から順に、第３ａレンズ群Ｇ３ａと開口絞りＳと第３ｂレンズ群Ｇ３ｂとから構成され、第３ａレンズ群Ｇ３ａは物体側に凸面を向けた負メニスカスレンズと物体側の面の曲率が強い両凸形状の正レンズとの接合レンズで構成され全体として正屈折力を有し、第３ｂレンズ群Ｇ３ｂは物体側の面の曲率が強い両凸形状の正レンズと物体側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され全体として正屈折力を有している。 The third lens group G3 is composed of a 3a lens group G3a, an aperture stop S, and a 3b lens group G3b in order from the object side along the optical axis. The 3a lens group G3a has a convex surface directed toward the object side. It is composed of a cemented lens of a negative meniscus lens and a biconvex positive lens having a strong curvature on the object side surface, and has a positive refractive power as a whole. The third lens group G3b has a biconvex shape with a strong curvature on the object side surface. The lens is composed of a positive lens having a shape and a cemented lens of a negative lens having a biconcave shape having a strong curvature on the object side surface, and has a positive refractive power as a whole.
第４レンズ群Ｇ４は、光軸に沿って物体側から順に、物体側の面が非球面の両凸形状の正レンズと、像側の面の曲率が強い両凸形状の正レンズと像側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され、全体として正屈折力を有している。 The fourth lens group G4 includes, in order from the object side along the optical axis, a biconvex positive lens having an aspheric object side surface, a biconvex positive lens having a strong curvature on the image side surface, and an image side. And has a positive refracting power as a whole.
第５レンズ群Ｇ５は、物体側に凸面を向けた正メニスカスレンズで構成され、全体として正屈折力を有している。 The fifth lens group G5 includes a positive meniscus lens having a convex surface directed toward the object side, and has a positive refracting power as a whole.
第５レンズ群Ｇ５の像側には、固体撮像素子の略ナイキスト周波数以上の解像力をカットするための光学ローパスフィルタＯＬＰＦが配置され、その像側には、撮像素子表面を保護するためのカバーガラスＣＧが配置されている。 On the image side of the fifth lens group G5, an optical low-pass filter OLPF for cutting the resolving power equal to or higher than the substantially Nyquist frequency of the solid-state image sensor is disposed, and on the image side, a cover glass for protecting the image sensor surface. CG is arranged.
以下の表３に本第３実施例にかかるズームレンズの諸元の値を掲げる。 Table 3 below provides values of specifications of the zoom lens according to the third example.
（表３）
［全体諸元］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 6.28 20.00 33.30
ＦＮｏ 2.9 4.1 4.7
２ω 85.1 30.5 18.4
ＴＬ 89.1 101.7 115.0
[レンズデータ]
面番号 曲率半径 面間隔 ｎｄ ν
1 94.9248 1.2000 1.84666 23.78
2 50.5101 6.0000 1.81600 46.63
3 181.5798 0.1000
4 40.5566 5.0000 1.49700 81.61
5 187.2247 (D5)
6 154.5189 2.3000 1.79668 45.37
7 7.7128 6.5500
8 -27.8647 0.9000 1.80400 46.58
9 13.4648 2.3000 1.84666 23.78
10 21.8957 0.2000
11 19.3217 3.1000 1.84666 23.78
12 -133.2414 (D12)
13 55.5404 1.3000 1.80100 34.96
14 24.2673 2.3000 1.49700 81.61
15 -25.0156 1.2000
16 ∞ 1.2000 (開口絞りＳ)
17 10.7357 4.1000 1.56384 60.69
18 -11.8874 1.1000 1.72000 50.24
19 19.9745 (D19)
20 35.0436 3.8000 1.67790 54.89
21 -13.3593 0.1000
22 29.1998 2.3000 1.48749 70.24
23 -23.6547 0.9000 1.80100 34.96
24 15.3609 (D24)
25 15.0119 2.5000 1.48749 70.24
26 46.5577 (D26)
27 ∞ 1.7200 1.51680 64.20 (OLPF)
28 ∞ 1.4410
29 ∞ 0.5000 1.51680 64.20 (CG)
30 ∞ (Bf)
［非球面データ］
面番号 κ Ｃ4 Ｃ6 Ｃ8 Ｃ10
7 0.7000 -7.4797E-06 -1.3581E-07 -4.3349E-09 4.8790E-11
20 1.0000 -1.9526E-04 -3.6202E-07 2.1862E-09 -1.5049E-10
［可変間隔データ］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 6.28 20.00 33.30
D5 2.2000 20.0116 30.1865
D12 20.7197 4.6820 2.4000
D19 3.8511 1.4736 1.3000
D24 7.2599 16.5136 23.1922
D26 2.0000 5.9210 4.7838
［条件式対応値］
（１）ｆ１／ｆＷ＝１１．８９
（２）ｆ１／（−ｆ２）＝８．５２
（３）ｆ５／ｆＷ＝７．０５
（４）ｆ３ａ／ｆ３ｂ＝０．５１１
(Table 3)
[Overall specifications]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 6.28 20.00 33.30
FNo 2.9 4.1 4.7
2ω 85.1 30.5 18.4
TL 89.1 101.7 115.0
[Lens data]
Surface number Curvature radius Surface spacing nd ν
1 94.9248 1.2000 1.84666 23.78
2 50.5101 6.0000 1.81600 46.63
3 181.5798 0.1000
4 40.5566 5.0000 1.49700 81.61
5 187.2247 (D5)
6 154.5189 2.3000 1.79668 45.37
7 7.7128 6.5500
8 -27.8647 0.9000 1.80400 46.58
9 13.4648 2.3000 1.84666 23.78
10 21.8957 0.2000
11 19.3217 3.1000 1.84666 23.78
12 -133.2414 (D12)
13 55.5404 1.3000 1.80100 34.96
14 24.2673 2.3000 1.49700 81.61
15 -25.0156 1.2000
16 ∞ 1.2000 (Aperture stop S)
17 10.7357 4.1000 1.56384 60.69
18 -11.8874 1.1000 1.72000 50.24
19 19.9745 (D19)
20 35.0436 3.8000 1.67790 54.89
21 -13.3593 0.1000
22 29.1998 2.3000 1.48749 70.24
23 -23.6547 0.9000 1.80100 34.96
24 15.3609 (D24)
25 15.0119 2.5000 1.48749 70.24
26 46.5577 (D26)
27 ∞ 1.7200 1.51680 64.20 (OLPF)
28 ∞ 1.4410
29 ∞ 0.5000 1.51680 64.20 (CG)
30 ∞ (Bf)
[Aspherical data]
Surface number κ C4 C6 C8 C10
7 0.7000 -7.4797E-06 -1.3581E-07 -4.3349E-09 4.8790E-11
20 1.0000 -1.9526E-04 -3.6202E-07 2.1862E-09 -1.5049E-10
[Variable interval data]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 6.28 20.00 33.30
D5 2.2000 20.0116 30.1865
D12 20.7197 4.6820 2.4000
D19 3.8511 1.4736 1.3000
D24 7.2599 16.5136 23.1922
D26 2.0000 5.9210 4.7838
[Conditional expression values]
(1) f1 / fW = 11.89
(2) f1 / (− f2) = 8.52
(3) f5 / fW = 7.05
(4) f3a / f3b = 0.511
図６は、本発明の第３実施例にかかるズームレンズのｄ線（λ＝５８７．６ｎｍ）に対する諸収差図を表し、（ａ）は広角端状態（Ｗ）を、（ｂ）は中間焦点距離状態（Ｍ）を、（ｃ）は望遠端状態（Ｔ）をそれぞれ表す。 6A and 6B are graphs showing various aberrations with respect to the d-line (λ = 587.6 nm) of the zoom lens according to the third example of the present invention. FIG. 6A shows the wide-angle end state (W), and FIG. 6B shows the intermediate focus. The distance state (M) and (c) represent the telephoto end state (T), respectively.
各収差図から、本第３実施例にかかるズームレンズは高い光学性能を有していることが明らかである。また、ズームレンズ全長が８９．１ｍｍ〜１１５．０ｍｍと小型であることが明らかである。 From each aberration diagram, it is clear that the zoom lens according to the third example has high optical performance. Also, it is clear that the overall zoom lens length is as small as 89.1 mm to 115.0 mm.
［第４実施例］
図７は、本発明の第４実施例にかかるズームレンズの無限遠合焦状態でのレンズ構成の断面図を示し、（Ｗ）は広角端状態を、（Ｍ）は中間焦点距離状態を、（Ｔ）は望遠端状態をそれぞれ示す。
[Fourth embodiment]
FIG. 7 is a cross-sectional view of the lens configuration of the zoom lens according to the fourth embodiment of the present invention in the infinitely focused state, (W) is the wide-angle end state, (M) is the intermediate focal length state, (T) indicates the telephoto end state.
図７において、本第４実施例にかかるズームレンズは、光軸に沿って物体側から順に、正屈折力を有する第１レンズ群Ｇ１と、負屈折力を有する第２レンズ群Ｇ２と、正屈折力を有する第３レンズ群Ｇ３と、正屈折力を有する第４レンズ群Ｇ４と、正屈折力を有する第５レンズ群Ｇ５とから構成され、広角端状態Ｗから望遠端状態Ｔまでズーミングする際に、無限遠合焦状態において、第１レンズ群Ｇ１と第２レンズ群Ｇ２との空気間隔は増加し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との空気間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との空気間隔は変化しながら減少し、第４レンズ群Ｇ４と第５レンズ群Ｇ５との空気間隔は増加するように、第１レンズ群Ｇ１は像面Ｉに対して移動し、第２レンズ群Ｇ２は像面Ｉ側に移動した後、物体側に移動するような軌跡で移動し、第３レンズ群Ｇ３は物体側に移動し、第４レンズ群Ｇ４は物体側に移動し、第５レンズ群Ｇ５は像面Ｉに対して移動し広角端状態Ｗよりも望遠端状態Ｔの方が物体側にある。 In FIG. 7, the zoom lens according to the fourth example includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens in order from the object side along the optical axis. A third lens group G3 having a refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are zoomed from the wide-angle end state W to the telephoto end state T. In the infinite focus state, the air gap between the first lens group G1 and the second lens group G2 increases, the air gap between the second lens group G2 and the third lens group G3 decreases, and the third The first lens group G1 has an image plane I such that the air gap between the lens group G3 and the fourth lens group G4 decreases while changing, and the air gap between the fourth lens group G4 and the fifth lens group G5 increases. The second lens group G2 has moved to the image plane I side. The third lens group G3 moves to the object side, the fourth lens group G4 moves to the object side, and the fifth lens group G5 moves relative to the image plane I. The telephoto end state T is closer to the object side than the wide-angle end state W.
第１レンズ群Ｇ１は、光軸に沿って物体側から順に、物体側に凸面を向けた負メニスカスレンズと物体側に凸面を向けた正メニスカスレンズとの接合レンズと、物体側に凸面を向けた正メニスカスレンズとから構成され、全体として正屈折力を有している。 The first lens group G1 includes, in order from the object side along the optical axis, a cemented lens of a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side, and the convex surface facing the object side. The positive meniscus lens has a positive refractive power as a whole.
第２レンズ群Ｇ２は、光軸に沿って物体側から順に、像側の面が非球面の両凹形状の負レンズと、像側の面の曲率が強い両凹形状の負レンズと物体側に凸面を向けた正メニスカスレンズとの接合レンズと、物体側の曲率が強い両凸形状の正レンズとから構成され、全体として負屈折力を有している。 The second lens group G2 includes, in order from the object side along the optical axis, a biconcave negative lens with an aspheric image side surface, a biconcave negative lens with a strong curvature on the image side surface, and an object side. The lens is composed of a cemented lens with a positive meniscus lens having a convex surface facing the surface, and a biconvex positive lens having a strong curvature on the object side, and has a negative refracting power as a whole.
第３レンズ群Ｇ３は、光軸に沿って物体側から順に、第３ａレンズ群Ｇ３ａと開口絞りＳと第３ｂレンズ群Ｇ３ｂとから構成され、第３ａレンズ群Ｇ３ａは物体側に凸面を向けた負メニスカスレンズと物体側の面の曲率が強い両凸形状の正レンズとの接合レンズで構成され全体として正屈折力を有し、第３ｂレンズ群Ｇ３ｂは物体側の面の曲率が強い両凸形状の正レンズと物体側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され全体として正屈折力を有している。 The third lens group G3 is composed of a 3a lens group G3a, an aperture stop S, and a 3b lens group G3b in order from the object side along the optical axis. The 3a lens group G3a has a convex surface directed toward the object side. It is composed of a cemented lens of a negative meniscus lens and a biconvex positive lens having a strong curvature on the object side surface, and has a positive refractive power as a whole. The third lens group G3b has a biconvex shape with a strong curvature on the object side surface. The lens is composed of a positive lens having a shape and a cemented lens of a negative lens having a biconcave shape having a strong curvature on the object side surface, and has a positive refractive power as a whole.
第４レンズ群Ｇ４は、光軸に沿って物体側から順に、物体側の面が非球面の両凸形状の正レンズと、像側の面の曲率が強い両凸形状の正レンズと物体側の面の曲率が強い両凹形状の負レンズとの接合レンズとから構成され、全体として正屈折力を有している。 The fourth lens group G4 includes, in order from the object side along the optical axis, a biconvex positive lens having an aspheric object side surface, a biconvex positive lens having a strong curvature on the image side surface, and an object side. And has a positive refracting power as a whole.
第５レンズ群Ｇ５は、物体側の面の曲率が強い両凸形状の正レンズと像側の面の曲率が強い両凹形状の負レンズとの接合レンズで構成され、全体として正屈折力を有している。 The fifth lens group G5 is composed of a cemented lens of a biconvex positive lens having a strong curvature on the object side surface and a biconcave negative lens having a strong curvature on the image side surface, and has a positive refracting power as a whole. Have.
第５レンズ群Ｇ５の像側には、固体撮像素子の略ナイキスト周波数以上の解像力をカットするための光学ローパスフィルタＯＬＰＦが配置され、その像側には、撮像素子表面を保護するためのカバーガラスＣＧが配置されている。 On the image side of the fifth lens group G5, an optical low-pass filter OLPF for cutting the resolving power equal to or higher than the substantially Nyquist frequency of the solid-state image sensor is disposed, and on the image side, a cover glass for protecting the image sensor surface. CG is arranged.
以下の表４に本第４実施例にかかるズームレンズの諸元の値を掲げる。 Table 4 below provides values of specifications of the zoom lens according to the fourth example.
（表４）
［全体諸元］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 7.30 32.00 74.00
ＦＮｏ 2.9 4.4 5.8
２ω 76.6 19.3 8.3
ＴＬ 98.7 111.2 128.0
[レンズデータ]
面番号 曲率半径 面間隔 ｎｄ ν
1 91.6356 1.2000 1.84666 23.78
2 43.7716 7.1000 1.78800 47.38
3 747.0564 0.1000
4 38.7003 4.3000 1.49700 81.61
5 157.8453 (D5)
6 -18910.9160 2.2000 1.77377 47.18
7 9.0966 6.1000
8 -25.1060 0.9000 1.77250 49.61
9 14.6234 2.5000 1.75520 27.51
10 42.2604 0.1000
11 25.5677 2.9000 1.84666 23.78
12 -321.7062 (D12)
13 41.3021 0.9000 1.85026 32.35
14 21.8613 2.5500 1.49700 81.61
15 -27.2167 1.200
16 ∞ 1.2000 (開口絞りＳ)
17 12.2623 3.7000 1.60738 56.82
18 -14.9954 0.9000 1.74320 49.32
19 19.6395 (D19)
20 22.6189 3.5000 1.60602 57.44
21 -18.2518 0.6000
22 28.7503 2.9000 1.48749 70.24
23 -26.2714 1.0000 1.80440 39.59
24 12.5700 (D24)
25 18.6304 3.4000 1.75500 52.32
26 -181.4509 0.9000 1.84666 23.78
27 66.4720 (D27)
28 ∞ 1.7200 1.51680 64.20 (OLPF)
29 ∞ 1.4410
30 ∞ 0.5000 1.51680 64.20 (CG)
31 ∞ (Bf)
［非球面データ］
面番号 κ Ｃ4 Ｃ6 Ｃ8 Ｃ10
7 0.9000 -2.0162E-05 -4.4138E-07 5.9139E-09 -1.1983E-10
20 1.0000 -1.1033E-04 -3.3050E-07 6.1431E-09 -1.0856E-10
［可変間隔データ］
レンズ状態 広角端状態 中間焦点距離状態 望遠端状態
f 7.30 32.00 74.00
D5 2.2000 22.0532 30.5865
D12 27.4585 6.9401 2.4000
D19 6.3397 1.5162 1.3000
D24 5.5885 18.4195 34.5624
D27 2.2607 7.5000 4.3401
［条件式対応値］
（１）ｆ１／ｆＷ＝８．３６
（２）ｆ１／（−ｆ２）＝６．１６
（３）ｆ５／ｆＷ＝４．７９
（４）ｆ３ａ／ｆ３ｂ＝０．３９０
(Table 4)
[Overall specifications]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 7.30 32.00 74.00
FNo 2.9 4.4 5.8
2ω 76.6 19.3 8.3
TL 98.7 111.2 128.0
[Lens data]
Surface number Curvature radius Surface spacing nd ν
1 91.6356 1.2000 1.84666 23.78
2 43.7716 7.1000 1.78800 47.38
3 747.0564 0.1000
4 38.7003 4.3000 1.49700 81.61
5 157.8453 (D5)
6 -18910.9160 2.2000 1.77377 47.18
7 9.0966 6.1000
8 -25.1060 0.9000 1.77250 49.61
9 14.6234 2.5000 1.75520 27.51
10 42.2604 0.1000
11 25.5677 2.9000 1.84666 23.78
12 -321.7062 (D12)
13 41.3021 0.9000 1.85026 32.35
14 21.8613 2.5500 1.49700 81.61
15 -27.2167 1.200
16 ∞ 1.2000 (Aperture stop S)
17 12.2623 3.7000 1.60738 56.82
18 -14.9954 0.9000 1.74320 49.32
19 19.6395 (D19)
20 22.6189 3.5000 1.60602 57.44
21 -18.2518 0.6000
22 28.7503 2.9000 1.48749 70.24
23 -26.2714 1.0000 1.80440 39.59
24 12.5700 (D24)
25 18.6304 3.4000 1.75500 52.32
26 -181.4509 0.9000 1.84666 23.78
27 66.4720 (D27)
28 ∞ 1.7200 1.51680 64.20 (OLPF)
29 ∞ 1.4410
30 ∞ 0.5000 1.51680 64.20 (CG)
31 ∞ (Bf)
[Aspherical data]
Surface number κ C4 C6 C8 C10
7 0.9000 -2.0162E-05 -4.4138E-07 5.9139E-09 -1.1983E-10
20 1.0000 -1.1033E-04 -3.3050E-07 6.1431E-09 -1.0856E-10
[Variable interval data]
Lens state Wide-angle end state Intermediate focal length state Telephoto end state
f 7.30 32.00 74.00
D5 2.2000 22.0532 30.5865
D12 27.4585 6.9401 2.4000
D19 6.3397 1.5162 1.3000
D24 5.5885 18.4195 34.5624
D27 2.2607 7.5000 4.3401
[Conditional expression values]
(1) f1 / fW = 8.36
(2) f1 / (− f2) = 6.16
(3) f5 / fW = 4.79
(4) f3a / f3b = 0.390
図８は、本発明の第４実施例にかかるズームレンズのｄ線（λ＝５８７．６ｎｍ）に対する諸収差図を表し、（ａ）は広角端状態（Ｗ）を、（ｂ）は中間焦点距離状態（Ｍ）を、（ｃ）は望遠端状態（Ｔ）をそれぞれ表す。 8A and 8B are graphs showing various aberrations with respect to the d-line (λ = 587.6 nm) of the zoom lens according to Example 4 of the present invention. FIG. 8A shows the wide-angle end state (W), and FIG. 8B shows the intermediate focus. The distance state (M) and (c) represent the telephoto end state (T), respectively.
各収差図から、本第４実施例にかかるズームレンズは高い光学性能を有していることが明らかである。また、ズームレンズ全長が９８．７ｍｍ〜１２８．０ｍｍと小型であることが明らかである。 From each aberration diagram, it is clear that the zoom lens according to the fourth example has high optical performance. In addition, it is clear that the overall length of the zoom lens is as small as 98.7 mm to 128.0 mm.
なお、本発明の実施例として、５群構成のレンズ系を示したが、該５群に付加レンズ群を加えただけのレンズ系も本発明の効果を内在した同等のレンズ系であることは言うまでもない。また、各レンズ群内の構成においても、実施例の構成に付加レンズを加えただけのレンズ群も本発明の効果を内在した同等のレンズ群であることは言うまでもない。 As an example of the present invention, a lens system having a five-group configuration is shown. However, a lens system in which an additional lens group is added to the five groups is also an equivalent lens system in which the effects of the present invention are inherent. Needless to say. In addition, in the configuration within each lens group, it goes without saying that a lens group in which an additional lens is added to the configuration of the embodiment is an equivalent lens group in which the effects of the present invention are inherent.
また、上述の実施の形態は例に過ぎず、上述の構成や形状に限定されるものではなく、本発明の範囲内において適宜修正、変更が可能である。 Further, the above-described embodiment is merely an example, and is not limited to the above-described configuration or shape, and can be appropriately modified and changed within the scope of the present invention.
Ｗ ・・・ 広角端状態
Ｍ ・・・ 中間状態
Ｔ ・・・ 望遠端状態
Ｇ１ ・・・ 第１レンズ群
Ｇ２ ・・・ 第２レンズ群
Ｇ３ ・・・ 第３レンズ群
Ｇ４ ・・・ 第４レンズ群
Ｇ５ ・・・ 第５レンズ群
Ｓ ・・・ 開口絞りＳ
Ｉ ・・・ 像面
Ｇ３ａ ・・・ 第３ａレンズ群
Ｇ３ｂ ・・・ 第３ｂレンズ群
ＯＬＰＦ・・・ 光学ローパスフィルタ
ＣＧ ・・・ カバーガラス
W: Wide-angle end state M ... Intermediate state T ... Telephoto end state G1 ... First lens group G2 ... Second lens group G3 ... Third lens group G4 ... Fourth Lens group G5: Fifth lens group S: Aperture stop S
I ... Image plane G3a ... 3a lens group G3b ... 3b lens group OLPF ... Optical low-pass filter CG ... Cover glass
Claims (8)
広角端状態から望遠端状態までズーミングする際に、無限遠合焦状態において、光軸に沿って、前記第１レンズ群と前記第２レンズ群との空気間隔は増加し、前記第２レンズ群と前記第３レンズ群との空気間隔は減少し、前記第３レンズ群と前記第４レンズ群との空気間隔は変化し、前記第４レンズ群と前記第５レンズ群との空気間隔は増加するように、前記第１レンズ群は像面に対して移動し、前記第２レンズ群は像面側に移動した後、物体側に移動するような軌跡で移動し、前記第３レンズ群は物体側に移動し、前記第４レンズ群は物体側に移動し、
光軸に沿って物体側から順に、前記第３レンズ群は正屈折力を有する第３ａレンズ群と、開口絞りと、第３ｂレンズ群とを有し、
光軸に沿って物体側から順に、前記第３ａレンズ群は負屈折力を有するレンズと正屈折力を有するレンズから成る接合レンズのみで構成され、前記第３ｂレンズ群は正屈折力を有するレンズと負屈折力を有するレンズから成る接合レンズのみで構成され、
以下の条件を満足することを特徴とするズームレンズ。
７．９３≦ｆ１／ｆＷ＜１２．８
５．８＜ｆ１／（−ｆ２）＜１０．０
３．０＜ｆ５／ｆＷ＜１０．０
但し、
ｆＷは広角端状態における前記ズームレンズ全系の焦点距離、
ｆ１は前記第１レンズ群の焦点距離、
ｆ２は前記第２レンズ群の焦点距離、
ｆ５は前記第５レンズ群の焦点距離を表す。 A first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens having positive refractive power in order from the object side along the optical axis. consists of a lens group, and the fifth lens group having positive refractive power,
When zooming from the wide-angle end state to the telephoto end state, the air space between the first lens group and the second lens group increases along the optical axis in the infinite focus state, and the second lens group And the third lens group are reduced, the air gap between the third lens group and the fourth lens group is changed, and the air gap between the fourth lens group and the fifth lens group is increased. The first lens group moves relative to the image plane, the second lens group moves toward the image plane side, and then moves along a trajectory that moves toward the object side. Moving to the object side, the fourth lens group moving to the object side,
In order from the object side along the optical axis, the third lens group includes a 3a lens group having positive refractive power, an aperture stop, and a 3b lens group.
In order from the object side along the optical axis, the 3a lens group includes only a cemented lens including a lens having negative refracting power and a lens having positive refracting power, and the 3b lens group has a lens having positive refracting power. And composed only of cemented lenses consisting of lenses with negative refractive power,
A zoom lens satisfying the following conditions:
7.93 ≦ f1 / fW <12.8
5.8 <f1 / (− f2) <10.0
3.0 <f5 / fW <10.0
However,
fW is the focal length of the entire zoom lens system in the wide-angle end state;
f1 is the focal length of the first lens group,
f2 is the focal length of the second lens group,
f5 represents the focal length of the fifth lens group.
−０．５０＜ｆ３ａ／ｆ３ｂ＜０．８０
但し、
ｆ３ａは前記第３ａレンズ群の焦点距離、
ｆ３ｂは前記第３ｂレンズ群の焦点距離を表す。 The zoom lens according to any one of claims 1 5, characterized in that the following condition is satisfied.
-0.50 <f3a / f3b <0.80
However,
f3a is the focal length of the 3a lens group,
f3b represents the focal length of the third b lens group.
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| JP2005098737A JP4882260B2 (en) | 2005-03-30 | 2005-03-30 | Zoom lens |
| US11/220,647 US7199940B2 (en) | 2004-09-15 | 2005-09-08 | Zoom lens system |
| US11/548,927 US7502173B2 (en) | 2004-09-15 | 2006-10-12 | Zoom lens system |
| US11/548,954 US7336425B2 (en) | 2004-09-15 | 2006-10-12 | Zoom lens system |
| US11/548,897 US7218456B2 (en) | 2004-09-15 | 2006-10-12 | Zoom lens system |
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| JP4288408B2 (en) * | 2003-02-20 | 2009-07-01 | 株式会社ニコン | Zoom lens with image shift |
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