JP2007108531A - Zoom lens, camera, and personal digital assistant - Google Patents

Zoom lens, camera, and personal digital assistant Download PDF

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JP2007108531A
JP2007108531A JP2005300745A JP2005300745A JP2007108531A JP 2007108531 A JP2007108531 A JP 2007108531A JP 2005300745 A JP2005300745 A JP 2005300745A JP 2005300745 A JP2005300745 A JP 2005300745A JP 2007108531 A JP2007108531 A JP 2007108531A
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lens
lens group
zoom
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object side
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Yoshifumi Sudo
芳文 須藤
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Ricoh Co Ltd
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Ricoh Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To obtain a zoom lens with which a zoom ratio of ≥2.8 times and high image quality can be obtained and which is sufficiently small in size in spite of a wide angle of view of ≥36° in half angle of view. <P>SOLUTION: The zoom lens comprises a first lens group G1 having a negative focal length, a second lens group G2 having a positive focal length, and a third lens group G3 having a positive focal length, and has a diaphragm moving integrally with the second lens group G2 on an object side. The second lens group G2 moves from an image side to the object side and the first lens group G1 moves in a convex arc shape to an image plane side at the time of variable magnification from a short focal end to a long focal end. The first lens group G1 comprises a negative meniscus lens of a convex face on the object side, a negative lens of a concave face on the object side, and a positive lens of a convex face on the object side, in order from the object side. The third lens group G3 consists of a spherical lens, and focusing is performed by the third lens group G3. The refractive index Nn of at least one negative lens of the first lens group G1 and the refractive index Np of a third lens of the first lens group G1 satisfy the conditions 2.2>Nn>2.0, 2.1>Np>1.8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は,伝統的な銀塩写真方式カメラ,デジタルカメラ,ビデオカメラ,カメラ付き携帯情報端末装置などに好適なズームレンズ,このズームレンズを用いた上記のような各種カメラおよび携帯情報端末装置に関するものである。   The present invention relates to a zoom lens suitable for a traditional silver halide photographic camera, digital camera, video camera, camera-equipped portable information terminal device, and the like, and various cameras and portable information terminal devices as described above using the zoom lens. Is.

現在,特にデジタルカメラ,ビデオカメラ,カメラ付き携帯情報端末装置などに関しては,高画質化,小型化,広画角化等のニーズが強くなっており,今後は,これらの要望に応えることができる製品を開発していく必要がある。そのため,これらに使用される撮影レンズとしては,ズーム比2.8倍以上のズームレンズであり,500万画素を超えるような受光素子に対応することができるような高画質化が求められ,さらに,小型化,広角化の両立が求められる。
デジタルカメラ用のズームレンズには多くの種類が考えられるが,小型化に適したタイプとして,物体側より順に,負の焦点距離を持つ第1レンズ群と,正の焦点距離を持つ第2レンズ群と,正の焦点距離を持つ第3レンズ群とを有し,短焦点端から長焦点端への変倍に際して,各レンズ群を移動させて変倍を行うズームレンズがある(例えば,特許文献1,特許文献2,特許文献3参照)。
Currently, digital cameras, video cameras, camera-equipped personal digital assistants, etc. are increasingly demanding higher image quality, smaller size, wider angle of view, etc., and will meet these demands in the future. It is necessary to develop products. For this reason, the photographic lens used for these is a zoom lens with a zoom ratio of 2.8 times or more, and there is a demand for high image quality that can accommodate a light receiving element exceeding 5 million pixels. , Miniaturization and wide angle are required.
There are many types of zoom lenses for digital cameras, but as a type suitable for miniaturization, a first lens group having a negative focal length and a second lens having a positive focal length in order from the object side. There is a zoom lens that has a lens group and a third lens group having a positive focal length, and performs zooming by moving each lens group when zooming from the short focus end to the long focus end (for example, a patent) Reference 1, Patent Document 2, and Patent Document 3).

特開2001−296475号公報JP 2001-296475 A 特開2002−365543号公報JP 2002-365543 A 特開2003−131134号公報JP 2003-131134 A

しかし,特許文献1,特許文献2に記載されているズームレンズは,半画角36°以上の広画角にすることができない。また,特許文献3に記載されているズームレンズでは,第3レンズ群に非球面を有することにより,像面補正を行っている。しかしながら,第3レンズ群に非球面を用いると,像面の補正には有効であるが,フォーカシングのために光軸に沿って移動した場合,フォーカシングによる像性能の劣化が発生する。   However, the zoom lenses described in Patent Document 1 and Patent Document 2 cannot have a wide field angle of 36 ° or more. In the zoom lens disclosed in Patent Document 3, the third lens group has an aspherical surface to perform image plane correction. However, if an aspherical surface is used for the third lens group, it is effective for correcting the image plane. However, when the lens unit moves along the optical axis for focusing, image performance is deteriorated due to focusing.

本発明は,以上の点に鑑みてなされたもので,請求項1記載の発明は,ズーム比2.8倍以上で,高画質が得られる高性能なレンズであり,かつ,半画角が36°以上の広画角でありながら,十分に小型である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 points. The invention according to claim 1 is a high-performance lens capable of obtaining a high image quality with a zoom ratio of 2.8 times or more, and has a half angle of view. An object of the present invention is to provide a zoom lens that is sufficiently small while having a wide angle of view of 36 ° or more.

請求項2,3および5記載の発明は,請求項1記載の発明において,より高性能化することができるズームレンズを提供することを目的としている。
請求項4記載の発明は,請求項3記載の発明において,コストパフォーマンスをより高めることができるズームレンズを提供することを目的としている。
請求項6および7記載の発明は,請求項1記載の発明において,高性能でありながら,より小型にすることができるズームレンズを提供することを目的としている。
The invention described in claims 2, 3 and 5 aims to provide a zoom lens capable of achieving higher performance in the invention described in claim 1.
The invention according to claim 4 is to provide a zoom lens capable of further improving cost performance in the invention according to claim 3.
The inventions described in claims 6 and 7 are to provide a zoom lens that is high performance but can be made smaller in the invention described in claim 1.

請求項8記載の発明は,ズーム比を2.8倍以上にすることができ,高性能,かつ,半画角36°以上の広画角でありながら,十分小型であるズームレンズを撮影光学系として使用した,小型で高画質の画像を得ることができるカメラを提供することを目的としている。   In the invention described in claim 8, the zoom ratio can be increased to 2.8 times or more, and a high-performance zoom lens having a sufficiently small half angle of view and a wide angle of view of 36 ° or more is provided. The purpose of the present invention is to provide a small camera that can obtain high-quality images.

請求項9記載の発明は,ズーム比を2.8倍以上にすることができ,高性能,かつ,半画角36°以上の広画角でありながら,十分小型であるズームレンズを撮影光学系として使用した,小型で高画質の画像を得ることができる携帯情報端末装置を提供することを目的としている。   According to the ninth aspect of the present invention, a zoom lens capable of increasing the zoom ratio to 2.8 times or more, having a high performance and a wide angle of view of a half angle of view of 36 ° or more, but having a sufficiently small size is provided as a photographic optical system. It is an object of the present invention to provide a portable information terminal device used as a system and capable of obtaining a small and high-quality image.

本発明のズームレンズは,物体側より順に,負の焦点距離を持つ第1レンズ群と,正の焦点距離を持つ第2レンズ群と,正の焦点距離を持つ第3レンズ群とを有し,第2レンズ群の物体側に第2レンズ群と一体に移動する絞りを有しており,短焦点端から長焦点端への変倍に際して,第2レンズ群は像側から物体側へ移動し,第1レンズ群は像面側に凸の弧状に移動するズームレンズであって,第1レンズ群は物体側から順に,物体側に凸面を向けた負メニスカスレンズと,像面側に凹面を向けた負レンズと,物体側に凸面を向けた正レンズの3枚を有し,第3レンズ群は球面レンズからなり,第3レンズ群でフォーカシングし,さらにそれぞれ以下のような特徴をもつものである。   The zoom lens of the present invention includes, in order from the object side, a first lens group having a negative focal length, a second lens group having a positive focal length, and a third lens group having a positive focal length. , Having an aperture that moves integrally with the second lens group on the object side of the second lens group, and the second lens group moves from the image side to the object side upon zooming from the short focus end to the long focus end The first lens group is a zoom lens that moves in a convex arc shape on the image plane side. The first lens group is a negative meniscus lens having a convex surface facing the object side in order from the object side, and a concave surface on the image plane side. A negative lens with a convex surface and a positive lens with a convex surface facing the object side. The third lens group consists of a spherical lens and is focused by the third lens group, and has the following characteristics. Is.

請求項1に記載のズームレンズは,第1レンズ群の少なくとも1枚の負レンズの屈折率をNn,第1レンズ群第3レンズの屈折率をNpとするとき,以下の条件を満足することを特徴とする。
2.2>Nn>2.0
2.1>Np>1.8
The zoom lens according to claim 1 satisfies the following conditions when the refractive index of at least one negative lens of the first lens group is Nn and the refractive index of the third lens of the first lens group is Np. It is characterized by.
2.2>Nn> 2.0
2.1>Np> 1.8

請求項2に記載のズームレンズは,νpを第1レンズ群の正レンズのアッベ数,νn1を第1レンズ群の負レンズの中で最も屈折率が高いレンズのアッベ数,νn2を第1レンズ群の負レンズの中で最も屈折率が高いレンズを除く負レンズのいずれか1枚のアッベ数とするとき,以下の条件を満足することを特徴とする。
νp<νn2<νn1
The zoom lens according to claim 2, wherein νp is the Abbe number of the positive lens in the first lens group, νn1 is the Abbe number of the lens having the highest refractive index among the negative lenses in the first lens group, and νn2 is the first lens. When the Abbe number of any one of the negative lenses excluding the lens having the highest refractive index among the negative lenses in the group is used, the following condition is satisfied.
νp <νn2 <νn1

請求項3に記載のズームレンズは,第1レンズ群の負レンズの像面側が非球面であることを特徴とする。
請求項4に記載のズームレンズは,第1レンズ群第2レンズの像面側が非球面であることを特徴とする。
請求項5に記載のズームレンズは,第2レンズ群が物体側から順に,正レンズ,負レンズ,正レンズ,正レンズの4枚からなることを特徴とする。
請求項6に記載のズームレンズは,第3レンズ群が正レンズ1枚からなることを特徴とする。
The zoom lens according to claim 3 is characterized in that the image plane side of the negative lens of the first lens group is an aspherical surface.
The zoom lens according to claim 4 is characterized in that the image plane side of the second lens in the first lens group is an aspherical surface.
The zoom lens according to claim 5 is characterized in that the second lens group includes four lenses in order from the object side: a positive lens, a negative lens, a positive lens, and a positive lens.
The zoom lens according to claim 6 is characterized in that the third lens group is composed of one positive lens.

請求項7に記載のズームレンズは,以下の条件を満足することを特徴とする。
0.4<fw/{−f1−f2+dt+(d1+d2)/2}<0.6
ただし,fwは短焦点端における焦点距離,f1,f2は第1レンズ群,第2レンズ群の焦点距離,dtは長焦点端における第1レンズ群の最も像側の面から第2レンズ群の第1面までの厚み,mは短焦点端から長焦点端に変倍する際の第1レンズ群と第2レンズ群の間隔変化量,d1,d2は第1レンズ群,第2レンズ群の厚みである。
The zoom lens according to claim 7 satisfies the following conditions.
0.4 <fw / {-f1-f2 + dt + (d1 + d2) / 2} <0.6
However, fw is the focal length at the short focal end, f1 and f2 are the focal lengths of the first lens group and the second lens group, and dt is the surface of the second lens group from the most image side surface of the first lens group at the long focal end. The thickness up to the first surface, m is the amount of change in the distance between the first lens group and the second lens group when zooming from the short focus end to the long focus end, and d1 and d2 are the first lens group and the second lens group. It is thickness.

ズームレンズを小型化するためには,収納長を短くすることと,撮影に使用するときのレンズ全長を短くすることが求められる。ここで,「収納長」とは各レンズ群の厚みの合計,「レンズ全長」とは最も物体側のレンズ面から像面までの距離とする。さらに,いわゆる沈胴タイプのカメラに用いるズームレンズにおいては,複数段からなる鏡胴の大型化を避けるためにレンズ径を小さくすることも重要である。   In order to reduce the size of the zoom lens, it is necessary to shorten the storage length and to shorten the total lens length when used for photographing. Here, “storage length” is the total thickness of each lens group, and “lens total length” is the distance from the lens surface closest to the object side to the image plane. Further, in a zoom lens used in a so-called retractable type camera, it is also important to reduce the lens diameter in order to avoid an increase in the size of a multi-stage lens barrel.

本発明のような,負正正の3つのレンズ群で構成されるズームレンズは,一般に,短焦点端から長焦点端への変倍に際して,第2レンズ群が像側から物体側へと移動し,第1レンズ群が変倍に伴う像面位置の変動を補正するように移動する。変倍機能の大半は第2レンズ群が負っており,第3レンズ群は主として像面から射出瞳を遠ざけるために設けられている。   A zoom lens composed of three negative and positive lens groups as in the present invention generally moves the second lens group from the image side to the object side upon zooming from the short focal end to the long focal end. Then, the first lens unit moves so as to correct the fluctuation of the image plane position accompanying the zooming. Most of the zooming function is borne by the second lens group, and the third lens group is provided mainly to keep the exit pupil away from the image plane.

このようなズームレンズでは,短焦点端における軸外光束が第1レンズ群の最も物体側の面で光軸から最も大きく離れる。よって,短焦点端における第1レンズ群の最も物体側の面の光線有効径で,ズームレンズ全体の最大外径が決まる。つまり,上記タイプのズームレンズのレンズ径を小さくすることは,第1レンズ群の最も物体側の面における軸外光束の光線高さを小さくすることに他ならない。   In such a zoom lens, the off-axis light beam at the short focal end is farthest away from the optical axis on the most object side surface of the first lens group. Therefore, the maximum outer diameter of the entire zoom lens is determined by the effective ray diameter of the surface closest to the object side of the first lens unit at the short focal end. That is, reducing the lens diameter of the zoom lens of the above type is nothing but reducing the height of the off-axis light beam on the most object side surface of the first lens group.

第1レンズ群の最も物体側の面における軸外光束の光線高さを小さくするためには,第1レンズ群の中で物体側に負の屈折力を有するレンズを,像側に正の屈折力を有するレンズを配置し,それぞれの屈折力を強めれば良い。収納長を短縮するためにも,各々の面で屈折力を強める必要がある。しかし,無闇にレンズの屈折力を強めることは,収差補正を困難にし,結像性能の劣化を招いてしまう。また,レンズ全長を小さくするには,変倍レンズ群が高い変倍機能を有し,変倍レンズ群の移動量が小さいことが必要である。   In order to reduce the height of the off-axis light beam on the most object side surface of the first lens group, a lens having a negative refractive power on the object side in the first lens group and a positive refraction on the image side are used. It is only necessary to arrange lenses having power and increase the refractive power of each lens. In order to shorten the storage length, it is necessary to increase the refractive power on each surface. However, increasing the refracting power of the lens without darkness makes it difficult to correct aberrations and leads to deterioration of imaging performance. In order to reduce the total lens length, it is necessary that the variable power lens group has a high variable power function and that the moving amount of the variable power lens group is small.

そこで,本発明においては,第1レンズ群は物体側から順に,物体側に凸面を向けた負メニスカスレンズL1と,像面側に凹面を向けた負レンズL2と,物体側に凸面を向けた正レンズL3の3枚を有し,少なくとも負レンズ1枚の像面側が非球面であり,かつ,以下の条件式を満足するように構成した。
2.2>Nn>2.0 (1)
2.1>Np>1.8 (2)
ただし,Nnは少なくとも1枚の負レンズの屈折率,NpはL3の屈折率である。
条件式(1)の下限値を超えると,収差を抑えつつ,軸外光束の光線高さを小さくすることが困難となってくる。上限値を超えると,コストが高くなる。(2)の下限値を超えると,像面湾曲の過剰補正となってくる。上限値を超えると,像面湾曲の補正不足となってくる。
Therefore, in the present invention, the first lens group has, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, a negative lens L2 having a concave surface facing the image surface side, and a convex surface facing the object side. Three positive lenses L3 are provided, and at least one negative lens has an aspheric image surface side, and the following conditional expression is satisfied.
2.2>Nn> 2.0 (1)
2.1>Np> 1.8 (2)
Here, Nn is the refractive index of at least one negative lens, and Np is the refractive index of L3.
When the lower limit of conditional expression (1) is exceeded, it becomes difficult to reduce the height of the off-axis light beam while suppressing aberrations. If the upper limit is exceeded, the cost increases. Exceeding the lower limit of (2) results in overcorrection of field curvature. If the upper limit is exceeded, field curvature correction will be insufficient.

また,より高い結像性能を得るには,以下の条件式を満足することが望ましい。
νp<νn2<νn1 (3)
ただし,νpは第1レンズ群の正レンズのアッベ数,νn1は第1レンズ群の負レンズの中で最も屈折率が高いレンズのアッベ数,νn2は第1レンズ群の負レンズの中で最も屈折率が高いレンズを除く負レンズのいずれか1枚のアッベ数である。
条件式(3)を満たさないと,軸上色収差を抑えることが困難となり,高性能化を妨げる。
In order to obtain higher imaging performance, it is desirable to satisfy the following conditional expression.
νp <νn2 <νn1 (3)
Where νp is the Abbe number of the positive lens in the first lens group, νn1 is the Abbe number of the lens having the highest refractive index among the negative lenses in the first lens group, and νn2 is the most negative lens in the first lens group. This is the Abbe number of any one of the negative lenses excluding a lens having a high refractive index.
If conditional expression (3) is not satisfied, it will be difficult to suppress the longitudinal chromatic aberration, which will hinder high performance.

また,軸外光線の屈折角が大きな面を非球面とすることにより,特に短焦点端における歪曲収差を抑制することが可能となるし,長焦点端では光束も太くなるため,球面収差,コマ収差の補正にも効果がある。
なお,非球面を2番目の負メニスカスレンズに設ければ,最も物体側の負メニスカスレンズに設ける場合に比べて,非球面レンズの外径が小さくなるため,加工およびコストの面で有利となる。
In addition, by making the surface with a large off-axis light refraction angle an aspherical surface, it becomes possible to suppress distortion, particularly at the short focal end, and the luminous flux becomes thick at the long focal end. It is also effective for correcting aberrations.
If an aspherical surface is provided on the second negative meniscus lens, the outer diameter of the aspherical lens is smaller than that provided on the most negative meniscus lens, which is advantageous in terms of processing and cost. .

また,第2レンズ群を物体側から順に,正レンズ,負レンズ,正レンズ,正レンズの4枚で構成することができる。第2レンズ群の物体側に開口絞りが配置される関係上,第2レンズ群内では開口絞りから遠い像側のレンズ面ほど軸外光線が光軸から離れた場所を通るため,軸外収差の補正に関与が深くなる。第2レンズ群は全体として,負のパワーを有するレンズの両側に正のパワーを有するレンズを配置した対称な配置であるが,軸外収差の補正に関与が深い像側の正のパワーを2枚のレンズに分割することによって自由度が増え,軸外収差の良好な補正が可能になる。   Further, the second lens group can be composed of four lenses in order from the object side: a positive lens, a negative lens, a positive lens, and a positive lens. Due to the fact that the aperture stop is disposed on the object side of the second lens group, off-axis aberrations occur because off-axis rays pass away from the optical axis toward the image side lens surface farther from the aperture stop in the second lens group. Will be deeply involved in the correction. The second lens group as a whole is a symmetrical arrangement in which lenses having a positive power are arranged on both sides of a lens having a negative power, but the image side positive power deeply involved in the correction of off-axis aberrations is 2 Dividing the lens into a single lens increases the degree of freedom and enables good correction of off-axis aberrations.

第3レンズ群は,これを正レンズ1枚で構成することにより,小型化が可能になる。   The third lens group can be reduced in size by constituting it with one positive lens.

収差を抑えつつ,レンズ全長を短縮するには,以下の条件式を満足することが望ましい。
0.4<fw/{−f1−f2+dt+(d1+d2)/2}<0.6 (4)
ただし,fwは短焦点端における焦点距離,f1,f2は第1レンズ群,第2レンズ群の焦点距離,dtは長焦点端における第1レンズ群の最も像側の面から第2レンズ群の第1面までの厚み,mは短焦点端から長焦点端に変倍する際の第1レンズ群と第2レンズ群の間隔変化量,d1,d2は第1レンズ群,第2レンズ群の厚みである。
条件式(4)の下限値を超えると,第1レンズ群が大型化する。また,レンズ全長が大きくなってしまう。上限値を超えると,第1レンズ群のパワーが必要以上に強まり,また,各レンズ群を必要以上に薄型化しなければならなくなり,全系の収差補正が困難になる。
In order to reduce the total lens length while suppressing aberrations, it is desirable to satisfy the following conditional expression.
0.4 <fw / {-f1-f2 + dt + (d1 + d2) / 2} <0.6 (4)
However, fw is the focal length at the short focal end, f1 and f2 are the focal lengths of the first lens group and the second lens group, and dt is the surface of the second lens group from the most image side surface of the first lens group at the long focal end. The thickness up to the first surface, m is the amount of change in the distance between the first lens group and the second lens group when zooming from the short focus end to the long focus end, and d1 and d2 are the first lens group and the second lens group. It is thickness.
If the lower limit of conditional expression (4) is exceeded, the first lens group will be enlarged. In addition, the total lens length becomes large. When the upper limit is exceeded, the power of the first lens group becomes stronger than necessary, and each lens group must be made thinner than necessary, making it difficult to correct aberrations of the entire system.

請求項1記載の発明によれば,ズーム比が2.8倍以上で,高画質を得ることができる高性能のズームレンズであり,かつ,半画角36°以上の広画角でありながら,十分に小型であるズームレンズを提供することができる。したがって,このズームレンズを例えばデジタルカメラに適用することにより,高画質で小型のデジタルカメラを実現することができる。   According to the first aspect of the present invention, the zoom ratio is 2.8 times or more, a high-performance zoom lens capable of obtaining high image quality, and a wide angle of view of a half angle of view of 36 ° or more. , A zoom lens that is sufficiently small can be provided. Therefore, by applying this zoom lens to, for example, a digital camera, a small digital camera with high image quality can be realized.

請求項2ないし請求項3記載の発明によれば,より高性能なズームレンズを提供することができるため,さらに高画質のデジタルカメラを実現することができる。
請求項4に記載の発明によれば,コストパフォーマンスが良好で高性能なズームレンズを提供することができるため,このズームレンズを例えばデジタルカメラに適用することにより,高画質でありながら,低コストのデジタルカメラを実現することができる。
According to the second to third aspects of the invention, since a higher-performance zoom lens can be provided, a higher-quality digital camera can be realized.
According to the invention described in claim 4, since it is possible to provide a zoom lens with good cost performance and high performance, by applying this zoom lens to, for example, a digital camera, it is possible to reduce the cost while maintaining high image quality. The digital camera can be realized.

請求項5に記載の発明によれば,より高性能なズームレンズを提供できるため,さらに高画質のデジタルカメラを実現することができる。
請求項6ないし請求項7に記載の発明によれば,高性能でありながら,より小型であるズームレンズを提供できるため,さらに高画質のデジタルカメラを実現することができる。
According to the fifth aspect of the present invention, since a higher-performance zoom lens can be provided, a higher-quality digital camera can be realized.
According to the invention described in claims 6 to 7, since it is possible to provide a zoom lens that has a high performance and a smaller size, it is possible to realize a digital camera with higher image quality.

請求項8記載の発明によれば,ズーム比が2.8倍以上で,高画質を得ることができる高性能のズームレンズであり,かつ,半画角が36°以上の広画角でありながら,十分小型であるズームレンズを,カメラの撮影光学系として使用することにより,小型で携帯性に優れ,高画質の画像を撮影することができるカメラを提供することができる。   According to the eighth aspect of the present invention, the zoom ratio is 2.8 times or more, a high-performance zoom lens capable of obtaining high image quality, and a wide angle of view with a half angle of view of 36 ° or more. However, by using a zoom lens that is sufficiently small as a photographing optical system for a camera, it is possible to provide a small camera that is excellent in portability and capable of photographing high-quality images.

請求項9記載の発明によれば,ズーム比が2.8倍以上で,高画質を得ることができる高性能のズームレンズであり,かつ,半画角が36°以上の広画角でありながら,十分小型であるズームレンズを,携帯情報端末装置の撮影光学系として使用することにより,小型で携帯性に優れ,高画質の画像を撮影することができる携帯情報端末装置を提供することができる。   According to the ninth aspect of the present invention, the zoom lens is a high-performance zoom lens capable of obtaining high image quality with a zoom ratio of 2.8 times or more, and a wide angle of view with a half angle of view of 36 ° or more. However, by using a zoom lens that is sufficiently small as a photographing optical system for a portable information terminal device, it is possible to provide a portable information terminal device that is small in size, excellent in portability, and capable of photographing high-quality images. it can.

以下に,本発明にかかるズームレンズの具体的な数値実施例を示す。各数値実施例における記号の意味は以下の通りである。
f:全系の焦点距離
F:Fナンバ
ω:半画角
R:曲率半径
D:面間隔
Nd:屈折率
νd:アッベ数
K:非球面の円錐定数
A4:4次の非球面係数
A6:6次の非球面係数
A8:8次の非球面係数
A10:10次の非球面係数
A12:12次の非球面係数
A14:14次の非球面係数
A16:16次の非球面係数
A18:18次の非球面係数
ただし,ここで用いられる非球面は,近軸曲率半径の逆数(近軸曲率)をc,光軸からの高さをHとするとき,以下の式で定義される。

Figure 2007108531
Specific numerical examples of the zoom lens according to the present invention will be described below. The meanings of symbols in each numerical example are as follows.
f: focal length of entire system F: F number ω: half angle of view R: radius of curvature D: surface spacing Nd: refractive index νd: Abbe number K: aspherical conical constant A4: fourth-order aspherical coefficient A6: 6 Next aspheric coefficient A8: 8th order aspheric coefficient A10: 10th order aspheric coefficient A12: 12th order aspheric coefficient A14: 14th order aspheric coefficient A16: 16th order aspheric coefficient A18: 18th order However, the aspherical surface used here is defined by the following equation, where c is the reciprocal of the paraxial curvature radius (paraxial curvature) and H is the height from the optical axis.

Figure 2007108531

図1〜図4は,数値実施例1〜数値実施例4にかかるズームレンズの光学配置を示す。各数値実施例にかかるズームレンズは,物体側より順に,負の焦点距離を持つ第1レンズ群G1と,正の焦点距離を持つ第2レンズ群G2と,正の焦点距離を持つ第3レンズ群G3を有し,第2レンズ群G2の物体側に第2レンズ群G2と一体に移動する絞り12を有している。図1〜図4に示す各レンズ群相互の相対的な配置関係は短焦点端での配置関係である。各図の各レンズ群の下方に記されている直線および曲線のように,短焦点端から長焦点端への変倍に際して,第2レンズ群G2は像側から物体側へ移動し,第1レンズ群G1は像面側に凸の弧状に移動する。第3レンズ群G3は,当初はほとんど移動せず,変倍の後半においてわずかずつ像面側に移動する。   1 to 4 show an optical arrangement of a zoom lens according to Numerical Example 1 to Numerical Example 4. FIG. The zoom lens according to each numerical example includes, in order from the object side, a first lens group G1 having a negative focal length, a second lens group G2 having a positive focal length, and a third lens having a positive focal length. It has a group G3, and has an aperture 12 that moves integrally with the second lens group G2 on the object side of the second lens group G2. The relative arrangement relationship between the lens groups shown in FIGS. 1 to 4 is the arrangement relationship at the short focal end. As shown by the straight lines and curves shown below each lens group in each figure, the second lens group G2 moves from the image side to the object side during zooming from the short focal end to the long focal end, and the first The lens group G1 moves in a convex arc shape on the image plane side. The third lens group G3 moves little at the beginning, and slightly moves toward the image plane side in the latter half of zooming.

第1レンズ群G1は,物体側から順に,物体側に凸面を向けた負メニスカスレンズL1と,像面側に凹面を向けた負レンズL2と,物体側に凸面を向けた正レンズL3の,3枚のレンズからなる。第2レンズ群G2は,物体側から順に,物体側に凸面を向けた正レンズL4と,このレンズL4の像面側に貼り付けられた凹レンズL5と,凸レンズL6および凸レンズL7の,4枚のレンズからなる。第3レンズ群G3は,1枚の凸レンズL8からなる。凸レンズL8は球面レンズからなるとともに,凸レンズL8からなる第3レンズ群G3でフォーカシングを行なうようになっている。像面は例えばCCDなどからなる撮像素子の受光面であり,像面の直前には平行平板からなる各種フィルタ15が配置されている。   The first lens group G1, in order from the object side, includes a negative meniscus lens L1 having a convex surface directed toward the object side, a negative lens L2 having a concave surface directed toward the image surface side, and a positive lens L3 having a convex surface directed toward the object side. Consists of three lenses. The second lens group G2, in order from the object side, includes a positive lens L4 having a convex surface facing the object side, a concave lens L5 attached to the image surface side of the lens L4, a convex lens L6, and a convex lens L7. It consists of a lens. The third lens group G3 is composed of a single convex lens L8. The convex lens L8 is formed of a spherical lens, and focusing is performed by a third lens group G3 including the convex lens L8. The image plane is a light-receiving surface of an image sensor made up of, for example, a CCD, and various filters 15 made up of parallel plates are arranged immediately before the image plane.

[数値実施例1]

Figure 2007108531
[Numerical Example 1]
Figure 2007108531

非球面;第4面
K=0.0,A4=−9.25925E−04,
A6=−1.46647E−05,A8=−3.16049E−07,
A10=−1.08378E−08,A12=−1.92078E−09,
A14=2.00272E−10,A16=−8.20627E−12,
A18=9.46606E−14
非球面;第8面
K=0.0,A4=−8.70139E−04,
A6=7.33082E−05,A8=−2.48754E−05,
A10=1.24459E−06,A12=4.78587E−07,
A14=−3.34212E−08,A16=−8.75692E−09,
A18=8.61847E−10
Aspherical surface; fourth surface K = 0.0, A4 = −9.25925E-04,
A6 = -1.46647E-05, A8 = -3.16049E-07,
A10 = −1.08378E−08, A12 = −1.92078E−09,
A14 = 2.000272E-10, A16 = −8.20627E-12
A18 = 9.46606E-14
Aspheric surface; eighth surface K = 0.0, A4 = −8.70139E-04,
A6 = 7.30882E-05, A8 = −2.48754E-05,
A10 = 1.24459E-06, A12 = 4.78587E-07,
A14 = −3.33422E-08, A16 = −8.775692E-09,
A18 = 8.61847E-10

間隔変化

Figure 2007108531
Interval change
Figure 2007108531

条件式数値
Nn=2.08000
Np=2.00060
νp=25.46
νn1=30.30
νn2=40.76
fw/{−f1−f2+dt+(d1+d2)/2}=0.46
(fw=4.32,f1=−10.67,f2=10.62,
dt=2.00,d1=7.84,d2=6.70)
Conditional expression numerical value Nn = 2.08000
Np = 2.00060
νp = 25.46
νn1 = 30.30
νn2 = 40.76
fw / {− f1−f2 + dt + (d1 + d2) / 2} = 0.46
(Fw = 4.32, f1 = -10.67, f2 = 10.62,
(dt = 2.00, d1 = 7.84, d2 = 6.70)

[数値実施例2]

Figure 2007108531
[Numerical Example 2]
Figure 2007108531

非球面;第2面
K=0.0,A4=−5.81175E−04,
A6=−7.79121E−06,A8=−4.91126E−07,
A10=−2.97839E−08,A12=1.55425E−10,
A14=3.17115E−11,A16=4.29147E−13,
A18=−1.08944E−13
非球面;第8面
K=0.0,A4=−7.77961E−04,
A6=9.51499E−05,A8=−2.49010E−05,
A10=6.90058E−07,A12=4.63908E−07,
A14=−1.62288E−08,A16=−8.26029E−09,
A18=6.46549E−10
Aspherical surface; second surface K = 0.0, A4 = −5.881175E-04,
A6 = −7.79121E-06, A8 = −4.991126E-07,
A10 = -2.97839E-08, A12 = 1.55425E-10,
A14 = 3.117115E-11, A16 = 4.29147E-13,
A18 = −1.08944E−13
Aspherical surface; eighth surface K = 0.0, A4 = −7.77961E-04,
A6 = 9.514999E-05, A8 = −2.491010E-05,
A10 = 6.90058E-07, A12 = 4.63908E-07,
A14 = -1.62288E-08, A16 = -8.26029E-09,
A18 = 6.464549E-10

間隔変化

Figure 2007108531
Interval change
Figure 2007108531

条件式
Nn=2.00060
Np=1.92286
νp=18.90
νn1=25.46
νn2=40.76
fw/{−f1−f2+dt+(d1+d2)/2}=0.53
(fw=4.32,f1=−10.59,f2=11.72,
dt=2.00,d1=6.61,d2=7.81)
Conditional expression Nn = 2.00060
Np = 1.92286
νp = 18.90
νn1 = 25.46
νn2 = 40.76
fw / {− f1−f2 + dt + (d1 + d2) / 2} = 0.53
(Fw = 4.32, f1 = -10.59, f2 = 11.72,
(dt = 2.00, d1 = 6.61, d2 = 7.81)

[数値実施例3]

Figure 2007108531
[Numerical Example 3]

Figure 2007108531

非球面;第2面
K=0.0,A4=−5.65096E−04,
A6=−1.37369E−05,A8=3.88064E−07,
A10=−7.01516E−08,A12=4.09699E−10,
A14=5.72111E−11,A16=3.64264E−12,
A18=−2.26192E−13
非球面;第8面
K=0.0,A4=−8.19639E−04,
A6=6.46931E−05,A8=−2.16398E−05,
A10=1.00058E−06,A12=4.23916E−07,
A14=−2.69786E−08,A16=−8.10204E−09,
A18=7.83159E−10
Aspherical surface; second surface K = 0.0, A4 = −5.66506E-04,
A6 = −1.33769E-05, A8 = 3.88804E-07,
A10 = −7.001516E−08, A12 = 4.09699E−10,
A14 = 5.71111E-11, A16 = 3.664264E-12
A18 = −2.626192E-13
Aspherical surface; eighth surface K = 0.0, A4 = −8.19639E-04,
A6 = 6.469931E-05, A8 = −2.16398E-05,
A10 = 1.00058E-06, A12 = 4.223916E-07,
A14 = −2.669786E-08, A16 = −8.10204E-09,
A18 = 7.83159E-10

間隔変化

Figure 2007108531
Interval change
Figure 2007108531

条件式
Nn=2.00330
Np=1.92286
νp=18.90
νn1=28.27
νn2=40.76
fw/{−f1−f2+dt+(d1+d2)/2}=0.47
(fw=4.32,f1=−11.24,f2=10.84,
dt=2.00,d1=6.43,d2=7.03)
Conditional expression Nn = 2.03030
Np = 1.92286
νp = 18.90
νn1 = 28.27
νn2 = 40.76
fw / {− f1−f2 + dt + (d1 + d2) / 2} = 0.47
(Fw = 4.32, f1 = -11.24, f2 = 10.84
(dt = 2.00, d1 = 6.43, d2 = 7.03)

[数値実施例4]

Figure 2007108531
[Numerical Example 4]
Figure 2007108531

非球面;第4面
K=0.0,A4=−1.11052E−03,
A6=−2.01355E−05,A8=−3.64788E−08,
A10=−7.49490E−08,A12=−6.39441E−10,
A14=2.21922E−10,A16=−7.43634E−12,
A18=−6.32104E−14
非球面;第8面
K=0.0,A4=−8.53141E−04,
A6=5.85228E−05,A8=−2.22709E−05,
A10=1.14534E−06,A12=4.78370E−07,
A14=−2.84565E−08,A16=−1.13280E−08,
A18=1.10736E−09
Aspherical surface; fourth surface K = 0.0, A4 = −1.11052E-03,
A6 = −2.01355E-05, A8 = −3.64788E-08,
A10 = −7.49490E−08, A12 = −6.39441E−10,
A14 = 2.19222E-10, A16 = −7.44364E-12,
A18 = −6.332104E-14
Aspherical surface; eighth surface K = 0.0, A4 = −8.5141E-04,
A6 = 5.885228E-05, A8 = −2.22709E-05,
A10 = 1.14534E-06, A12 = 4.778370E-07,
A14 = −2.84565E-08, A16 = −1.13280E-08,
A18 = 1.10736E-09

間隔変化

Figure 2007108531
Interval change
Figure 2007108531

条件式
Nn=2.02204
Np=2.00060
νp=18.90
νn1=29.06
νn2=40.73
fw/{−f1−f2+dt+(d1+d2)/2}=0.45
(fw=4.32,f1=−10.80,f2=10.41,
dt=2.00,d1=7.58,d2=6.75)
Conditional expression Nn = 2.2044
Np = 2.00060
νp = 18.90
νn1 = 29.06
νn2 = 40.73
fw / {− f1−f2 + dt + (d1 + d2) / 2} = 0.45
(Fw = 4.32, f1 = -10.80, f2 = 10.41,
(dt = 2.00, d1 = 7.58, d2 = 6.75)

各数値実施例にかかるズームレンズの各種収差曲線を図5乃至図16に示す。図5乃至図7は,数値実施例1の,短焦点端,中間焦点距離,長焦点端における収差を示す。図8乃至図10は,数値実施例2の,短焦点端,中間焦点距離,長焦点端における収差を示す。図11乃至図13は,数値実施例3の,短焦点端,中間焦点距離,長焦点端における収差を示す。図14乃至図16は,数値実施例4の,短焦点端,中間焦点距離,長焦点端における収差を示す。球面収差の破線は正弦条件を表す。非点収差図中の実線はサジタル,破線はメリディオナルを表す。これらの収差図からわかるように,各数値実施例ともに,収差は十分に補正されている。各数値実施例のようにズームレンズを構成することで,ズーム比が2.8倍以上で,半画角36°以上の広角であり,かつ,小型で,非常に良好な像性能を確保することができるズームレンズを得ることができる。   Various aberration curves of the zoom lens according to each numerical example are shown in FIGS. 5 to 7 show aberrations of the numerical example 1 at the short focal end, the intermediate focal length, and the long focal end. 8 to 10 show aberrations of the numerical example 2 at the short focal end, the intermediate focal length, and the long focal end. 11 to 13 show aberrations of the numerical example 3 at the short focal end, the intermediate focal length, and the long focal end. 14 to 16 show aberrations of the numerical example 4 at the short focal end, the intermediate focal length, and the long focal end. The broken line of spherical aberration represents the sine condition. In the astigmatism diagram, the solid line represents sagittal and the broken line represents meridional. As can be seen from these aberration diagrams, the aberrations are sufficiently corrected in each numerical example. By configuring the zoom lens as in each numerical example, the zoom ratio is 2.8 times or more, the wide angle is 36 ° or more, and the size is small, so that very good image performance is ensured. A zoom lens can be obtained.

次に,これまで説明してきたズームレンズを撮影用光学系として有するデジタルカメラの実施例について説明する。図17において,デジタルカメラは,撮影レンズ1と受光素子(エリアセンサ)を有し,撮影レンズ1によって形成される撮影対象物の像を受光素子上で読み取るように構成されている。この撮影レンズ1としては,上記数値実施例1〜4の何れかのズームレンズを用いることができる。デジタルカメラの前面には,上記撮影レンズ1のほかに,光学ファインダ窓2,ストロボ発光器の発光部3が配置されている。カメラの上面には,シャッタボタン4が配置されている。カメラの背面には,電源スイッチ6,液晶モニタ7,各種操作を行なう操作スイッチ8,ズーミング操作スイッチ10,通信カード9の装填スロットが配置されている。   Next, an embodiment of a digital camera having the zoom lens described so far as a photographing optical system will be described. In FIG. 17, the digital camera has a photographic lens 1 and a light receiving element (area sensor), and is configured to read an image of a photographing object formed by the photographic lens 1 on the light receiving element. As the photographic lens 1, any of the zoom lenses of the numerical examples 1 to 4 can be used. In addition to the photographing lens 1, an optical finder window 2 and a light emitting unit 3 of a strobe light emitter are disposed on the front surface of the digital camera. A shutter button 4 is disposed on the upper surface of the camera. On the back of the camera, a power switch 6, a liquid crystal monitor 7, an operation switch 8 for performing various operations, a zooming operation switch 10, and a loading slot for a communication card 9 are arranged.

上記受光素子からの出力は,図示されない中央演算装置の制御を受ける信号処理装置によって処理され,デジタル情報に変換される。信号処理装置によってデジタル化された画像情報は,中央演算装置の制御を受ける画像処理装置において所定の画像処理を受けた後,半導体メモリに記録される。液晶モニタ7には撮影中の画像を表示することもできるし,半導体メモリに記録されている画像を表示することもできる。また,半導体メモリに記録した画像は通信カード9等を使用して外部へ送信することも可能である。   The output from the light receiving element is processed by a signal processing device under the control of a central processing unit (not shown) and converted into digital information. The image information digitized by the signal processing device is subjected to predetermined image processing in the image processing device controlled by the central processing unit, and then recorded in the semiconductor memory. The liquid crystal monitor 7 can display an image being photographed, and can also display an image recorded in the semiconductor memory. The image recorded in the semiconductor memory can also be transmitted to the outside using the communication card 9 or the like.

シャッタボタン4の半押しによりフォーカシングがなされる。撮影レンズ1のズームレンズにおいて,フォーカシングは前記第3レンズ群G3の移動によって行う。シャッタボタン4をさらに押し込むと撮影がなされ,その後は既述の処理がなされる。   Focusing is performed by half-pressing the shutter button 4. In the zoom lens of the taking lens 1, focusing is performed by moving the third lens group G3. When the shutter button 4 is further pressed, shooting is performed, and thereafter, the processing described above is performed.

ズームレンズが使用されるカメラとしてデジタルカメラの例で説明したが,本発明にかかるズームレンズは,カメラの類であればどのようなものにも使用することができる。例えば,ビデオカメラ,伝統的な銀塩写真方式カメラなどにも使用することができる。また,カメラ機能部を有する携帯電話,PDA,携帯型のパソコンなど,携帯情報端末装置の撮影用光学系として,本発明にかかるズームレンズを使用することができる。   Although an example of a digital camera has been described as a camera using a zoom lens, the zoom lens according to the present invention can be used for any camera. For example, it can also be used for video cameras, traditional silver halide photography cameras, etc. Moreover, the zoom lens according to the present invention can be used as a photographing optical system of a portable information terminal device such as a mobile phone having a camera function unit, a PDA, or a portable personal computer.

本発明の数値実施例1にかかるズームレンズを示す光学配置図である。1 is an optical arrangement diagram showing a zoom lens according to Numerical Example 1 of the present invention. FIG. 本発明の数値実施例2にかかるズームレンズを示す光学配置図である。It is an optical arrangement | positioning figure which shows the zoom lens concerning Numerical Example 2 of this invention. 本発明の数値実施例3にかかるズームレンズを示す光学配置図である。It is an optical arrangement | positioning figure which shows the zoom lens concerning Numerical Example 3 of this invention. 本発明の数値実施例4にかかるズームレンズを示す光学配置図である。It is an optical arrangement | positioning figure which shows the zoom lens concerning Numerical Example 4 of this invention. 本発明の数値実施例1にかかるズームレンズの短焦点端における収差曲線図である。FIG. 6 is an aberration curve diagram at a short focal end of the zoom lens according to Numerical Example 1 of the present invention. 本発明の数値実施例1にかかるズームレンズの中間焦点距離における収差曲線図である。FIG. 6 is an aberration curve diagram at an intermediate focal length of the zoom lens according to Numerical Example 1 of the present invention. 本発明の数値実施例1にかかるズームレンズの長焦点端における収差曲線図である。FIG. 4 is an aberration curve diagram at the long focal end of the zoom lens according to Numerical Example 1 of the present invention. 本発明の数値実施例2にかかるズームレンズの短焦点端における収差曲線図である。It is an aberration curve figure in the short focus end of the zoom lens concerning Numerical Example 2 of the present invention. 本発明の数値実施例2にかかるズームレンズの中間焦点距離における収差曲線図である。FIG. 6 is an aberration curve diagram at an intermediate focal length of a zoom lens according to Numerical Example 2 of the present invention. 本発明の数値実施例2にかかるズームレンズの長焦点端における収差曲線図である。It is an aberration curve figure in the long focal end of the zoom lens concerning Numerical Example 2 of the present invention. 本発明の数値実施例3にかかるズームレンズの短焦点端における収差曲線図である。It is an aberration curve figure in the short focus end of the zoom lens concerning Numerical Example 3 of the present invention. 本発明の数値実施例3にかかるズームレンズの中間焦点距離における収差曲線図である。FIG. 9 is an aberration curve diagram at an intermediate focal length of the zoom lens according to Numerical Example 3 of the present invention. 本発明の数値実施例3にかかるズームレンズの長焦点端における収差曲線図である。It is an aberration curve figure in the long focal end of the zoom lens concerning Numerical Example 3 of the present invention. 本発明の数値実施例4にかかるズームレンズの短焦点端における収差曲線図である。It is an aberration curve figure in the short focal end of the zoom lens concerning Numerical Example 4 of the present invention. 本発明の数値実施例4にかかるズームレンズの中間焦点距離における収差曲線図である。FIG. 10 is an aberration curve diagram at an intermediate focal length of the zoom lens according to Numerical Example 4 of the present invention. 本発明の数値実施例4にかかるズームレンズの長焦点端における収差曲線図である。It is an aberration curve figure in the long focal end of the zoom lens concerning Numerical Example 4 of the present invention. 本発明にかかるカメラの実施例を示す,(A)は正面側の斜視図,(B)は裏面側の斜視図である。1A and 1B show a camera according to an embodiment of the present invention, in which FIG. 1A is a front perspective view, and FIG.

符号の説明Explanation of symbols

L1:第1レンズ
L2:第2レンズ
L3:第3レンズ
L4:第4レンズ
L5:第5レンズ
L6:第6レンズ
L7:第7レンズ
L8:第8レンズ
G1:第1レンズ群
G2:第2レンズ群
G3:第3レンズ群
12:絞り
15:各種フィルタ
L1: first lens L2: second lens L3: third lens L4: fourth lens L5: fifth lens L6: sixth lens L7: seventh lens L8: eighth lens G1: first lens group G2: second Lens group G3: Third lens group 12: Aperture 15: Various filters

Claims (9)

物体側より順に,負の焦点距離を持つ第1レンズ群と,正の焦点距離を持つ第2レンズ群と,正の焦点距離を持つ第3レンズ群を有し,上記第2レンズ群の物体側に第2レンズ群と一体に移動する絞りを有し,
短焦点端から長焦点端への変倍に際して,第2レンズ群は像側から物体側へ移動し,第1レンズ群は像面側に凸の弧状に移動するズームレンズであって,
第1レンズ群は,物体側から順に,物体側に凸面を向けた負メニスカスレンズと,像面側に凹面を向けた負レンズと,物体側に凸面を向けた正レンズの3枚を有し,
第3レンズ群は球面レンズからなるとともに,第3レンズ群でフォーカシングし,
Nnを第1レンズ群の少なくとも1枚の負レンズの屈折率,Npを第1レンズ群の正レンズの屈折率としたとき,
2.2>Nn>2.0
2.1>Np>1.8
の条件式を満足することを特徴とするズームレンズ。
In order from the object side, the first lens group having a negative focal length, the second lens group having a positive focal length, and the third lens group having a positive focal length, the object of the second lens group A diaphragm that moves integrally with the second lens group on the side,
When zooming from the short focus end to the long focus end, the second lens group is moved from the image side to the object side, and the first lens group is a zoom lens that moves in an arc shape convex toward the image plane side,
The first lens group has three lenses in order from the object side: a negative meniscus lens having a convex surface facing the object side, a negative lens having a concave surface facing the image surface side, and a positive lens having a convex surface facing the object side. ,
The third lens group is composed of spherical lenses, and focusing is performed with the third lens group.
When Nn is the refractive index of at least one negative lens in the first lens group, and Np is the refractive index of the positive lens in the first lens group,
2.2>Nn> 2.0
2.1>Np> 1.8
A zoom lens satisfying the following conditional expression:
請求項1記載のズームレンズにおいて,νpを第1レンズ群の正レンズのアッベ数,νn1を第1レンズ群の負レンズの中で最も屈折率が高いレンズのアッベ数,νn2を第1レンズ群の負レンズの中で最も屈折率が高いレンズを除く負レンズのいずれか1枚のアッベ数としたとき,
νp<νn2<νn1
の条件式を満足することを特徴とするズームレンズ。
2. The zoom lens according to claim 1, wherein νp is the Abbe number of the positive lens in the first lens group, νn1 is the Abbe number of the lens having the highest refractive index among the negative lenses in the first lens group, and νn2 is the first lens group. When the Abbe number of any one of the negative lenses other than the negative lens with the highest refractive index is used,
νp <νn2 <νn1
A zoom lens that satisfies the following conditional expression:
請求項1または2記載のズームレンズにおいて,第1レンズ群の少なくとも1枚の負レンズの像面側が非球面であることを特徴とするズームレンズ。   3. The zoom lens according to claim 1, wherein an image surface side of at least one negative lens in the first lens group is an aspherical surface. 請求項3記載のズームレンズにおいて,物体側から数えて2番目の負レンズの像面側が非球面であることを特徴とするズームレンズ   4. The zoom lens according to claim 3, wherein the image plane side of the second negative lens counted from the object side is an aspherical surface. 請求項1〜4記載のズームレンズにおいて,第2レンズ群が物体側から順に,正レンズ,負レンズ,正レンズ,正レンズの4枚からなることを特徴とするズームレンズ   5. The zoom lens according to claim 1, wherein the second lens group includes four lenses in order from the object side: a positive lens, a negative lens, a positive lens, and a positive lens. 請求項1〜5記載のズームレンズにおいて,第3レンズ群が1枚の正レンズからなることを特徴とするズームレンズ。   6. The zoom lens according to claim 1, wherein the third lens group is composed of one positive lens. 請求項1〜6記載のズームレンズにおいて,fwは短焦点端における焦点距離,f1,f2は第1レンズ群,第2レンズ群の焦点距離,dtは長焦点端における第1レンズ群の最も像側の面から第2レンズ群の第1面までの厚み,mは短焦点端から長焦点端に変倍する際の第1レンズ群と第2レンズ群の間隔変化量,d1,d2は第1レンズ群,第2レンズ群の厚みとしたとき,
0.4<fw/{−f1−f2+dt+(d1+d2)/2}<0.6
の条件式を満足することを特徴とするズームレンズ。
7. The zoom lens according to claim 1, wherein fw is a focal length at a short focal end, f1 and f2 are focal lengths of a first lens group and a second lens group, and dt is a most image of the first lens group at a long focal end. The thickness from the side surface to the first surface of the second lens group, m is the amount of change in the distance between the first lens group and the second lens group when zooming from the short focal end to the long focal end, and d1 and d2 are the first With the thickness of one lens group and the second lens group,
0.4 <fw / {-f1-f2 + dt + (d1 + d2) / 2} <0.6
A zoom lens that satisfies the following conditional expression:
請求項1〜7記載のズームレンズを,撮影用光学系として有することを特徴とするカメラ。   A camera comprising the zoom lens according to claim 1 as a photographing optical system. 請求項1〜7記載のズームレンズを,カメラ機能部の撮影用光学系として有することを特徴とする携帯情報端末装置。   A portable information terminal device comprising the zoom lens according to claim 1 as a photographing optical system of a camera function unit.
JP2005300745A 2005-10-14 2005-10-14 Zoom lens, camera, and personal digital assistant Pending JP2007108531A (en)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7372636B2 (en) 2006-02-28 2008-05-13 Ricoh Company, Ltd. Zoom lens and image-taking device
US7535653B2 (en) 2006-03-20 2009-05-19 Ricoh Company, Ltd. Zoom lens, imaging device and camera device and mobile information terminal using the zoom lens
JP2009204699A (en) * 2008-02-26 2009-09-10 Tamron Co Ltd Zoom lens
US7623298B2 (en) 2007-09-11 2009-11-24 Ricoh Company, Ltd. Zoom lens, camera apparatus, and portable information terminal apparatus
US7715122B2 (en) 2007-10-01 2010-05-11 Samsung Digital Imaging Co., Ltd. Wide-angle zoom optic system
JP2010122458A (en) * 2008-11-19 2010-06-03 Sony Corp Zoom lens and image pickup device
JP2010271669A (en) * 2009-05-25 2010-12-02 Ricoh Co Ltd Imaging lens, camera device and personal digital assistant
US8736973B2 (en) 2011-05-23 2014-05-27 Canon Kabushiki Kaisha Zoom lens and image pickup apparatus equipped with zoom lens
US9122041B2 (en) 2011-09-02 2015-09-01 Samsung Electronics Co., Ltd. Zoom lens and photographing apparatus including the same
CN109656002A (en) * 2019-02-25 2019-04-19 深圳市点睛创视技术有限公司 A kind of Miniature projection lens
JP7438795B2 (en) 2020-03-09 2024-02-27 キヤノン株式会社 Zoom lenses and imaging devices

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7372636B2 (en) 2006-02-28 2008-05-13 Ricoh Company, Ltd. Zoom lens and image-taking device
US7535653B2 (en) 2006-03-20 2009-05-19 Ricoh Company, Ltd. Zoom lens, imaging device and camera device and mobile information terminal using the zoom lens
US7623298B2 (en) 2007-09-11 2009-11-24 Ricoh Company, Ltd. Zoom lens, camera apparatus, and portable information terminal apparatus
US7715122B2 (en) 2007-10-01 2010-05-11 Samsung Digital Imaging Co., Ltd. Wide-angle zoom optic system
JP2009204699A (en) * 2008-02-26 2009-09-10 Tamron Co Ltd Zoom lens
US8031256B2 (en) 2008-11-19 2011-10-04 Sony Corporation Zoom lens and image pickup device
JP2010122458A (en) * 2008-11-19 2010-06-03 Sony Corp Zoom lens and image pickup device
JP2010271669A (en) * 2009-05-25 2010-12-02 Ricoh Co Ltd Imaging lens, camera device and personal digital assistant
US8736973B2 (en) 2011-05-23 2014-05-27 Canon Kabushiki Kaisha Zoom lens and image pickup apparatus equipped with zoom lens
US9122041B2 (en) 2011-09-02 2015-09-01 Samsung Electronics Co., Ltd. Zoom lens and photographing apparatus including the same
CN109656002A (en) * 2019-02-25 2019-04-19 深圳市点睛创视技术有限公司 A kind of Miniature projection lens
CN109656002B (en) * 2019-02-25 2024-04-16 深圳市点睛创视技术有限公司 Miniature projection lens
JP7438795B2 (en) 2020-03-09 2024-02-27 キヤノン株式会社 Zoom lenses and imaging devices

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