JP2015227984A5

JP2015227984A5 -

Info

Publication number: JP2015227984A5
Application number: JP2014114028A
Authority: JP
Filing date: 2014-06-02
Publication date: 2017-07-06
Anticipated expiration: 2034-06-02

Description

本発明のズームレンズは、物体側より像側へ順に配置された、負の屈折力の第１レンズ群、正の屈折力の第２レンズ群、正の屈折力の第３レンズ群より構成され、ズーミングに際して隣り合うレンズ群の間隔が変化するズームレンズにおいて、
前記第１レンズ群は、最も物体側に配置された負レンズＧ１１を含む複数のレンズより構成され、
前記第１レンズ群の焦点距離をｆ１、前記第２レンズ群の焦点距離をｆ２、前記負レンズＧ１１の物体側のレンズ面と像側のレンズ面の曲率半径を各々Ｒ１１、Ｒ１２とするとき、
−０．９＜ｆ１／ｆ２＜−０．２
０．１０＜（Ｒ１１＋Ｒ１２）／（Ｒ１１−Ｒ１２）＜０．５５
なる条件式を満足することを特徴としている。 The zoom lens according to the present invention includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. In zoom lenses in which the distance between adjacent lens groups changes during zooming,
The first lens group includes a plurality of lenses including a negative lens G11 disposed closest to the object side ,
When the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the curvature radii of the object-side lens surface and the image-side lens surface of the negative lens G11 are R11 and R12, respectively.
−0.9 <f1 / f2 <−0.2
0.10 <(R11 + R12) / (R11-R12) <0.55
It satisfies the following conditional expression.

以下、本発明のズームレンズ及びそれを有する撮像装置を図面に基づいて説明する。本発明のズームレンズは、物体側より像側へ順に配置された、負の屈折力の第１レンズ群、正の屈折率の第２レンズ群、正の屈折力の第３レンズ群より構成されている。そしてズーミングに際して隣り合うレンズ群の間隔が変化する。 Hereinafter, a zoom lens of the present invention and an imaging apparatus having the same will be described with reference to the drawings. The zoom lens according to the present invention includes a first lens group having a negative refractive power, a second lens group having a positive refractive index, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. ing. The distance between adjacent lens units changes during zooming.

各実施例は物体側より像側へ順に、負の屈折力の第１レンズ群Ｌ１、正の屈折力の第２レンズ群Ｌ２、正の屈折力の第３レンズ群Ｌ３より構成される３群構成のズームレンズである。広角端から望遠端へのズーミングに際しては各レンズ群が矢印の如く移動する。具体的には広角端から望遠端へのズーミングに際して、第１レンズ群Ｌ１は像側に凸状の軌跡で移動し、第２レンズ群Ｌ２は単調に物体側に移動し、第３レンズ群Ｌ３は物体側に移動する。 In each example, in order from the object side to the image side, three groups including a first lens unit L1 having a negative refractive power, a second lens unit L2 having a positive refractive power, and a third lens unit L3 having a positive refractive power. This is a zoom lens having a configuration. When zooming from the wide-angle end to the telephoto end, each lens unit moves as indicated by an arrow. Specifically, during zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves along a locus convex to the image side, the second lens unit L2 monotonously moves to the object side, and the third lens unit L3 Moves to the object side.

負レンズＧ１１の像側に隣接して配置されたレンズＧ１２の物体側のレンズ面の曲率半径をＲ２１とする。負レンズＧ１１の物体側のレンズ面の屈折力をｆＲ１１とする。レンズ面の屈折力ｆＲ１１は負レンズＧ１１の材料の屈折率をＮ１ｎ、レンズ面の曲率半径をＲ１１とするとき、
ｆＲ１１＝Ｒ１１／（Ｎ１ｎ−１）
で定義される。 And R21 radius of curvature of the lens surface on the object side of the lens G12 which is disposed adjacent to the image side of the negative lens G11. The refractive power of the object-side lens surface of the negative lens G11 is defined as fR11. The refractive power fR11 of the lens surface is N1n as the refractive index of the material of the negative lens G11, and R11 as the radius of curvature of the lens surface.
fR11 = R11 / (N1n-1)
Defined by

第１レンズ群Ｌ１の最も物体側のレンズ面から第１レンズ群Ｌ１の最も像側のレンズ面までの距離をＤ１とする。負レンズＧ１１の焦点距離をｆ１ｎとする。第１レンズ群Ｌ１に含まれる正レンズの材料の屈折率と、アッベ数を各々Ｎ１ｐ、ν１ｐとする。 The distance from the most object side lens surface of the first lens unit L1 to the most image side lens surface of the first lens unit L1 is defined as D1. Let the focal length of the negative lens G11 be f1n. The refractive index and Abbe number of the positive lens material included in the first lens unit L1 are N1p and ν1p, respectively.

このとき次の条件式のうち１つ以上を満足するのが良い。
−２０．０＜（Ｒ１２＋Ｒ２１）／（Ｒ１２−Ｒ２１）＜−３．５・・・（３）
−０．９５＜ｆ２／ｆＲ１１＜−０．５５・・・（４）
−１．０＜Ｄ１／ｆ１＜−０．４・・・（５）
０．４＜ｆ１ｎ／ｆ１＜０．７・・・（６）
Ｎ１ｐ＞１．９・・・（７）
ν１ｐ＜１９．０・・・（８）
但し、第１レンズ群Ｌ１は条件式（７）、（８）を満足する材料から構成される正レンズを少なくとも１つ有していれば良い。次に前述の各条件式の技術的意味について説明する。 At this time, one or more of the following conditional expressions should be satisfied.
-20.0 <(R12 + R21) / (R12-R21) <-3.5 (3)
−0.95 <f2 / fR11 <−0.55 (4)
−1.0 <D1 / f1 <−0.4 (5)
0.4 <f1n / f1 <0.7 (6)
N1p> 1.9 (7)
ν1p <19.0 (8)
However, the first lens unit L1 only needs to include at least one positive lens made of a material that satisfies the conditional expressions (7) and (8). Next, the technical meaning of each conditional expression described above will be described.

次に各レンズ群のレンズ構成について説明する。第１レンズ群Ｌ１は物体側のレンズ面が凹で両凹形状の負レンズＧ１１と負レンズＧ１１の像側に配置された物体側のレンズ面が凸でメニスカス形状の正レンズＧ１２で構成している。全系の小型化を図るために第１レンズ群Ｌ１の負の屈折力を適切な範囲で強めている。このとき、第１レンズ群Ｌ１内より発生する諸収差、特に広角端において歪曲収差、像面湾曲が多く発生してくる。このとき、第１レンズ群Ｌ１で発生する歪曲収差を許容し、像面湾曲を補正する様に構成している。 Next, the lens configuration of each lens group will be described. The first lens unit L1 includes a negative lens G11 having a concave object-side lens surface and a positive meniscus lens G12 having a convex object-side lens surface disposed on the image side of the negative lens G11. Yes. In order to reduce the size of the entire system, the negative refractive power of the first lens unit L1 is increased within an appropriate range. At this time, various aberrations generated from within the first lens unit L1, particularly distortion and field curvature are generated at the wide angle end. At this time, it is configured to allow distortion aberration generated in the first lens unit L1 and correct curvature of field.

Claims

A first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side, and are adjacent to each other during zooming In zoom lenses where the interval of
The first lens group includes a plurality of lenses including a negative lens G11 disposed closest to the object side ,
When the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the curvature radii of the object-side lens surface and the image-side lens surface of the negative lens G11 are R11 and R12, respectively.
−0.9 <f1 / f2 <−0.2
0.10 <(R11 + R12) / (R11-R12) <0.55
A zoom lens satisfying the following conditional expression:

When the radius of curvature of the object-side lens surface of the lens G12 arranged adjacent to the image side of the negative lens G11 is R21,
-20.0 <(R12 + R21) / (R12-R21) <-3.5
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.

When the refractive power of the object side lens surface of the negative lens G11 is fR11,
−0.95 <f2 / fR11 <−0.55
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.

When the distance from the most object side lens surface of the first lens group to the most image side lens surface of the first lens group is D1,
−1.0 <D1 / f1 <−0.4
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.

When the focal length of the negative lens G11 is f1n,
0.4 <f1n / f1 <0.7
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.

Before SL refractive index and Abbe number, respectively the N1p positive lens of the material included in the first lens group, when the .nu.1p, the first lens group,
N1p> 1.9
ν1p <19.0
The zoom lens according to claim 1, further comprising a positive lens made of a material that satisfies the following conditional expression.

The zoom according to any one of claims 1 to 6, wherein the first lens group includes the negative lens G11 and a positive lens arranged on the image side of the negative lens G11. lens.

The zoom lens according to any one of claims 1 to 7, wherein an effective image circle diameter on the wide-angle side is smaller than an effective image circle diameter at the telephoto end.

An image pickup apparatus comprising: the zoom lens according to claim 1; and an image pickup element that receives an image formed by the zoom lens.