[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

JPH09211325A - Compact zoom lens - Google Patents

Compact zoom lens

Info

Publication number
JPH09211325A
JPH09211325A JP3431596A JP3431596A JPH09211325A JP H09211325 A JPH09211325 A JP H09211325A JP 3431596 A JP3431596 A JP 3431596A JP 3431596 A JP3431596 A JP 3431596A JP H09211325 A JPH09211325 A JP H09211325A
Authority
JP
Japan
Prior art keywords
lens
group
negative
positive
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP3431596A
Other languages
Japanese (ja)
Inventor
Takeshi Nishimura
威志 西村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP3431596A priority Critical patent/JPH09211325A/en
Publication of JPH09211325A publication Critical patent/JPH09211325A/en
Pending legal-status Critical Current

Links

Landscapes

  • Lenses (AREA)

Abstract

PROBLEM TO BE SOLVED: To obtain a wide angle at specified variable power ratio, to shorten the whole length of a lens and to obtain high optical performance within a whole variable power range by properly setting the lens constitution of respective lens groups and properly setting an aspherical surface and the material of the lens. SOLUTION: A variable power action is executed to a telephoto end from a wide angle end by moving the 1st lens group L1 having positive refractive power and the 2nd lens group L2 having negative refractive power while reducing a gap between both lens groups L1 and L2. In such a case, the 1st group L1 is constituted of a 11th and a 12th positive meniscuses whose convex surfaces are faced to an object side and a 13th and a 14th negative lenses consisting of the plastic material and having at least one aspherical surface. The 2nd group L2 is constituted so as to be provided with a 21st positive lens consisting of the plastic material whose convex surf ace is faced to an image surface side and having at least one aspherical surface and a 22nd negative meniscus whose convex surface is faced to the image surface side. Then, an image is enlarged while correcting the image forming performance of the first group L1 by using the second group L2.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【発明の属する技術分野】本発明はレンズシャッターカ
メラ、ビデオカメラ等に好適な2つのレンズ群より成る
小型のズームレンズに関し、特に各レンズ群のレンズ構
成を適切に設定することにより、収差補正を良好に行う
と共にレンズ全長(第1レンズ面から像面までの距離)
の短縮化を図った広角端の撮影画角が60〜70度と広
画角の変倍比2程度の小型のズームレンズに関するもの
である。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact zoom lens composed of two lens groups suitable for a lens shutter camera, a video camera, etc., and particularly, by properly setting the lens configuration of each lens group, aberration correction can be performed. Good performance and total lens length (distance from the first lens surface to the image surface)
The present invention relates to a compact zoom lens having a wide-angle-end photographing field angle of 60 to 70 degrees and a zoom ratio of about 2 at the wide-angle end.

【0002】[0002]

【従来の技術】最近、レンズシャッターカメラ、ビデオ
カメラ等の小型化に伴いレンズ全長の短い小型のズーム
レンズが要望されている。又、非球面加工の向上に伴
い、非球面を有効に用いてレンズ枚数を少なくした簡易
な構成の小型のズームレンズが種々と提案されている。
レンズ全長の短い簡易な構成のズームレンズとして、物
体側より順に正の屈折力の第1群と負の屈折力の第2群
の2つのレンズ群で構成し、両レンズ群の間隔を変えて
変倍する望遠タイプの小型の所謂2群ズームレンズが種
々と提案されている。この2群ズームレンズは比較的バ
ックフォーカスを短くすることができ、又レンズ系全体
の小型化が容易である為にレンズシャッターカメラ等に
多く用いられている。
2. Description of the Related Art Recently, with the miniaturization of lens shutter cameras, video cameras and the like, there has been a demand for a compact zoom lens having a short overall lens length. Further, with the improvement of aspherical surface processing, various compact zoom lenses having a simple structure in which the number of lenses is reduced by effectively using aspherical surfaces have been proposed.
As a zoom lens having a simple structure with a short total lens length, it is composed of two lens groups, a first lens group having a positive refractive power and a second lens group having a negative refractive power in order from the object side, and the distance between both lens groups is changed. There are various proposals for a so-called two-group zoom lens of a telephoto type that varies the magnification. This two-group zoom lens has a relatively short back focus and is easy to downsize the entire lens system, so that it is often used in lens shutter cameras and the like.

【0003】本出願人はこのような2群ズームレンズを
先に特開昭56−128911号公報、特開昭57−2
01213号公報、特開昭60−170816号公報、
特開昭60−191216号公報、特開昭62−569
17号公報、特開昭62−90611号公報、特開昭6
4−57222号公報、特開平3−116110号公報
等において提案している。
The applicant of the present invention has previously proposed such a two-group zoom lens in JP-A-56-128911 and JP-A-57-2.
No. 01213, JP-A-60-170816,
JP-A-60-191216 and JP-A-62-569.
17, JP-A-62-90611, JP-A-6-9061
It is proposed in Japanese Patent Laid-Open No. 4-57222, Japanese Patent Laid-Open No. 3-116110, and the like.

【0004】この他、特開昭63−311224号公報
では、正の屈折力の第1群を正レンズ、負レンズ、正レ
ンズ、そして正レンズの4つのレンズより構成し、負の
屈折力の第2群を正レンズと負レンズの2つのレンズよ
り構成し、各レンズ群中に非球面を設けて光学性能の向
上を図った2群ズームレンズが提案されている。
In addition, in Japanese Unexamined Patent Publication No. 63-311224, the first lens unit having a positive refractive power is composed of four lenses, that is, a positive lens, a negative lens, a positive lens, and a positive lens. A two-group zoom lens has been proposed in which the second group is composed of two lenses, a positive lens and a negative lens, and an aspherical surface is provided in each lens group to improve optical performance.

【0005】又、特開平4−161914号公報では、
正の屈折力の第1群を正レンズ、負レンズ、非球面レン
ズ、そして正レンズの4つのレンズより構成し、負の屈
折力の第2群を非球面を含む3つのレンズより構成し
て、光学性能の向上を図った2群ズームレンズが提案さ
れている。
Further, in Japanese Patent Laid-Open No. 4-161914,
The first group of positive refracting power is composed of four lenses of a positive lens, a negative lens, an aspherical lens and a positive lens, and the second group of negative refracting power is composed of three lenses including an aspherical surface. , A two-group zoom lens with improved optical performance has been proposed.

【0006】[0006]

【発明が解決しようとする課題】前述した正の屈折力の
第1群と負の屈折力の第2群の2つのレンズ群より成る
2群ズームレンズにおいて、レンズ系全体の小型化を図
りつつ、2倍程度の変倍比を有しつつ、全変倍範囲にわ
たり良好なる光学性能を得るには、各レンズ群のレンズ
構成を適切に設定するとともに各レンズ群に適切なる形
状の非球面を用いるのが効果的である。
In the above-described two-group zoom lens composed of two lens groups, the first lens group having a positive refractive power and the second lens group having a negative refractive power, the overall lens system is downsized. In order to obtain good optical performance over the entire zoom range while having a zoom ratio of about 2 times, the lens configuration of each lens group should be set appropriately and an aspherical surface of an appropriate shape should be used for each lens group. It is effective to use.

【0007】先の特開昭63−311224号公報で提
案されている2群ズームレンズはガラス材より成る非球
面レンズを用いているが、各レンズ群の屈折力が比較的
弱い為にレンズ系全体が大型化する傾向があった。
The two-group zoom lens proposed in Japanese Patent Laid-Open No. 63-311224 uses an aspherical lens made of a glass material. However, since the refractive power of each lens group is relatively weak, the lens system The whole tended to increase in size.

【0008】又、特開平4−161914号公報で提案
されている2群ズームレンズはプラスチック材より成る
非球面レンズを用いているが、望遠端において第1レン
ズ面から最終レンズ面までの長さが比較的長く、レンズ
全長が長大化する傾向があった。
The two-group zoom lens proposed in Japanese Unexamined Patent Publication No. 4-161914 uses an aspherical lens made of plastic material, and the length from the first lens surface to the final lens surface at the telephoto end. Is relatively long, and the total lens length tends to increase.

【0009】一般に2群ズームレンズにおいては、第
1,第2群の双方の屈折力を強めれば変倍における各レ
ンズ群の移動量が少なくなり、レンズ全長の短縮化が可
能となる。しかしながら、各レンズ群の屈折力を単に強
めると変倍に伴う収差変動が大きくなり、これを良好に
補正するのが難しくなってくるという問題点が生じてく
る。
Generally, in a two-group zoom lens, if the refractive powers of both the first and second groups are strengthened, the amount of movement of each lens group during zooming is reduced, and the overall lens length can be shortened. However, simply increasing the refracting power of each lens group causes a large variation in aberration due to zooming, which makes it difficult to satisfactorily correct this.

【0010】本発明は、所謂2群のズームレンズにおい
て、各レンズ群のレンズ構成を適切に設定するとともに
非球面及びそれを用いるレンズの材質を適切に設定する
ことにより、変倍比2程度で広画角を有しつつ、レンズ
全長の短縮化を図った全変倍範囲にわたり高い光学性能
を有した小型のズームレンズの提供を目的とする。
According to the present invention, in a so-called two-group zoom lens, by appropriately setting the lens configuration of each lens group and appropriately setting the material of the aspherical surface and the lens using the same, the zoom ratio is about 2. An object of the present invention is to provide a small-sized zoom lens having a wide angle of view and a high optical performance over the entire zoom range in which the total lens length is shortened.

【0011】[0011]

【課題を解決するための手段】第1発明としての小型の
ズームレンズは、 (1−1)物体側より順に正の屈折力の第1群と負の屈
折力の第2群の2つのレンズ群を有し、両レンズ群の間
隔を変えて変倍を行う小型のズームレンズにおいて、該
第1群は物体側へ凸面を向けたメニスカス状の正の第1
1レンズと負の第12レンズとプラスチック材より成
り、少なくとも1つの非球面を有した負の第13レンズ
そして正の第14レンズより成り、該第2群は像面側に
凸面を向けたプラスチック材より成り、少なくとも1つ
の非球面を有した正の第21レンズと像面側に凸面を向
けたメニスカス状の負の第22レンズを有していること
を特徴としている。
A small zoom lens as a first invention is (1-1) two lenses of a first group having a positive refractive power and a second group having a negative refractive power in order from the object side. In a small-sized zoom lens having a group and performing zooming by changing the distance between both lens groups, the first group is a meniscus-shaped positive first lens whose convex surface faces the object side.
One lens, a negative twelfth lens, and a plastic material, a negative thirteenth lens having at least one aspherical surface, and a positive fourteenth lens, and the second group is a plastic with a convex surface facing the image side. It is characterized by having a positive 21st lens made of a material and having at least one aspherical surface and a meniscus negative 22nd lens having a convex surface facing the image side.

【0012】第2発明としての小型のズームレンズは、 (1−2)物体側より順に正の屈折力の第1群と負の屈
折力の第2群の2つのレンズ群を有し、両レンズ群の間
隔を変えて変倍を行う小型のズームレンズにおいて、該
第1群は物体側へ凸面を向けたメニスカス状の正の第1
1レンズと負の第12レンズ、少なくとも1つの非球面
を有した負の第13レンズそして正の第14レンズより
成り、該第2群は少なくとも1つの非球面を有し像面側
に凸面を向けた正の第21レンズ、負の第22レンズを
有し、該第13レンズと第21レンズの材質のアッベ数
を各々ν13,ν21とするとき、 ν13<40 ・・・・・・(1) ν21<40 ・・・・・・(2) なる条件を満足することを特徴としている。
A compact zoom lens as a second invention comprises (1-2) two lens groups, a first group having a positive refractive power and a second group having a negative refractive power, which are arranged in order from the object side. In a compact zoom lens that performs zooming by changing the distance between lens groups, the first group is a meniscus-shaped first positive lens whose convex surface faces the object side.
1 lens and a negative twelfth lens, a negative thirteenth lens having at least one aspherical surface and a positive fourteenth lens, and the second group has at least one aspherical surface and a convex surface on the image side. If the Abbe numbers of the materials of the thirteenth lens and the twenty-first lens are ν13 and ν21, respectively, ν13 <40 (1) ) Ν21 <40 ··· (2) It is characterized by satisfying the condition.

【0013】[0013]

【発明の実施の形態】図1〜図6は本発明の数値実施例
1〜6の広角端のレンズ断面図である。図中、L1は正
の屈折力の第1群、L2は負の屈折力の第2群であり、
両レンズ群の間隔を減少させつつ、両レンズ群を矢印の
如く物体側へ移動させて広角端から望遠端への変倍を行
っている。IPは像面である。
1 to 6 are lens cross-sectional views at wide-angle end according to Numerical Embodiments 1 to 6 of the present invention. In the figure, L1 is the first group of positive refractive power, L2 is the second group of negative refractive power,
While reducing the distance between both lens groups, both lens groups are moved to the object side as shown by the arrow to perform zooming from the wide-angle end to the telephoto end. IP is an image plane.

【0014】まず、第1発明としてのレンズ構成の特徴
について説明する。
First, the features of the lens structure as the first invention will be described.

【0015】第1発明としての実施形態では、該第1群
は物体側へ凸面を向けたメニスカス状の正の第11レン
ズと負の第12レンズとプラスチック材より成り、少な
くとも1つの非球面を有した負の第13レンズそして正
の第14レンズより成り、該第2群は像面側に凸面を向
けたプラスチック材より成り、少なくとも1つの非球面
を有した正の第21レンズと像面側に凸面を向けたメニ
スカス状の負の第22レンズを有するように構成してい
る。
In the embodiment as the first invention, the first group is composed of a positive meniscus eleventh lens having a convex surface facing the object side, a negative twelfth lens, and a plastic material, and at least one aspherical surface. A negative thirteenth lens and a positive fourteenth lens, and the second group is made of a plastic material having a convex surface facing the image plane side, and has a positive twenty-first lens having at least one aspherical surface and an image plane. It is configured to have a negative meniscus 22nd lens with the convex surface facing the side.

【0016】第1発明のズームレンズにおいては、第1
群の結像性能を第2群で補正しながら拡大するようにし
ている。この為、第1群を諸収差を良好に補正可能なレ
ンズ構成にしている。本実施形態では第1群を単焦点レ
ンズとして良好な収差補正が容易な正、負、正の屈折力
の3つのレンズ成分よりなる、所謂トリプレットを基本
構成としている。そしてトリプレットを構成する負の第
2レンズ成分を、負の球面レンズ(第12レンズ)と負
の屈折力の弱い非球面レンズ(第13レンズ)の2つの
レンズ成分に分割している。そして該非球面レンズをレ
ンズ周辺にいくに従い負の屈折力が強くなる非球面形状
とし、これにより軸上(球面収差)と軸外の諸収差をバ
ランス良く補正している。
In the zoom lens of the first invention, the first
The second group is used to correct the image forming performance of the group while expanding. For this reason, the first group has a lens configuration capable of properly correcting various aberrations. In the present embodiment, a so-called triplet is used as a basic configuration, in which the first lens unit is a single-focus lens and three lens components having positive, negative, and positive refracting powers that facilitate good aberration correction are easy. The negative second lens component forming the triplet is divided into two lens components, a negative spherical lens (twelfth lens) and a negative aspheric lens (thirteenth lens) having a weak refractive power. Then, the aspherical lens has an aspherical shape in which the negative refracting power becomes stronger toward the periphery of the lens, so that on-axis (spherical aberration) and various off-axis aberrations are corrected in a well-balanced manner.

【0017】このように第1群を正の第11レンズ、負
の第12レンズ、非球面を有する第13レンズ、そして
正の第14レンズの4つのレンズより構成して、諸収差
を良好に補正している。
As described above, the first group is composed of four lenses, ie, the positive eleventh lens, the negative twelfth lens, the aspherical thirteenth lens, and the positive fourteenth lens, and various aberrations are satisfactorily achieved. Correcting.

【0018】又、第2群は広角端と望遠端とで軸外光束
が通過する箇所が大きくなる為、非球面レンズを用いる
ことによって広角端と望遠端とでバランス良く収差補正
を行っている。具体的には、第2群を像面側へ凸面を向
け、レンズ周辺部にいくに従って正の屈折力が強くなる
形状の非球面を有する正の第21レンズと負の第22レ
ンズとすることで、特に広角端におけるコマ収差等の軸
外収差を良好に補正すると共にレンズ系全体の小型化を
実現している。
Further, in the second lens group, since the portion through which the off-axis light beam passes at the wide-angle end and the telephoto end becomes large, aberrations are well-balanced at the wide-angle end and the telephoto end by using an aspherical lens. . Specifically, the second lens unit should be a positive 21st lens and a negative 22nd lens that have an aspherical surface with a shape in which the positive refractive power increases toward the lens periphery, with the convex surface facing the image side. In particular, off-axis aberrations such as coma at the wide-angle end are well corrected, and the overall size of the lens system is reduced.

【0019】正、負の屈折力の2つのレンズ群より成る
2群ズームレンズにおいて、第2群は像面に近いところ
に位置する。この為、第2群のレンズ外径は大きくなる
為、ローコスト化を図る為には第2群の各レンズにロー
コストの材質を用いることが良い。第1発明では第2群
を正の第21レンズと負の第22レンズより構成し、こ
のとき負の第22レンズに比較的高い屈折率の材質を用
いて、これにより像面特性を良好に補正している。
In a two-group zoom lens composed of two lens groups having positive and negative refracting powers, the second group is located near the image plane. For this reason, the outer diameter of the lens of the second group becomes large. Therefore, in order to reduce the cost, it is preferable to use a low-cost material for each lens of the second group. In the first invention, the second group is composed of the positive 21st lens and the negative 22nd lens. At this time, a material having a relatively high refractive index is used for the negative 22nd lens, and thereby the image plane characteristic is improved. Correcting.

【0020】特に第1発明では、第2群を像面側へ凸面
を向けたメニスカス状の正の屈折力の非球面を有する第
21レンズと像面側へ凸面を向けたメニスカス状の負の
第22レンズの2枚で構成し、かつ第21レンズの材質
をプラスチックとすることによりローコスト化を図って
いる。
In particular, in the first aspect of the invention, the 21st lens having a positive meniscus aspherical surface with the second lens unit having a convex surface directed toward the image side and the negative meniscus lens having a convex surface directed toward the image surface side are provided. The cost is reduced by constructing the two lenses of the 22nd lens and making the material of the 21st lens plastic.

【0021】また第1発明においては、更に前記第i群
の焦点距離をfi、広角端における全系の焦点距離をf
wとするとき、 0.5<f1/fw<0.9 ・・・・・・・・(3) 0.5<|f2/fw|<0.9 ・・・・・・(4) なる条件を満足するようにしている。これにより高い光
学性能を維持しつつ、レンズ系全体の小型化を図ってい
る。
In the first invention, the focal length of the i-th group is fi and the focal length of the entire system at the wide-angle end is f.
When w, 0.5 <f1 / fw <0.9 (3) 0.5 <| f2 / fw | <0.9 (4) I try to satisfy the conditions. As a result, the overall lens system is miniaturized while maintaining high optical performance.

【0022】条件式(3)は第1群の焦点距離と広角端
における全系の焦点距離との比に関し、主に第1群を小
型化するためのものである。条件式(3)の上限値を越
えて、第1群の屈折力が弱くなり過ぎると第1群の変倍
時の移動量が増大し、レンズ系が大型化してしまうので
良くない。また下限値を越えて第1群の屈折力が強くな
り過ぎるとレンズ系の小型化においては有利であるが、
第1群からの収差の発生量が増大しすぎて、これを第2
群で補正しきれなくなるため良くない。しかも第1群の
傾き偏心による像面の傾き量が増大し高精度なレンズ保
持機構を必要とし、保持機構が複雑化すると共に高コス
トとなるため良くない。
Conditional expression (3) relates to the ratio between the focal length of the first lens unit and the focal length of the entire system at the wide-angle end, and is mainly for downsizing the first lens unit. If the upper limit of conditional expression (3) is exceeded and the refractive power of the first lens unit becomes too weak, the amount of movement of the first lens unit during zooming increases, and the lens system becomes large, which is not preferable. Further, if the lower limit is exceeded and the refractive power of the first lens unit becomes too strong, it is advantageous in downsizing the lens system.
The amount of aberration generated from the first group increases too much,
It is not good because the group can no longer correct. Moreover, the amount of tilt of the image plane due to the tilt decentering of the first group increases, which requires a highly accurate lens holding mechanism, which complicates the holding mechanism and increases the cost.

【0023】第1発明において更に光学性能と小型化を
バランス良く保つためには、条件式(3)の上限値を
0.75とすることが望ましい。また下限値を0.55
とすることが望ましい。
In the first aspect of the present invention, in order to maintain a good balance between optical performance and miniaturization, it is desirable to set the upper limit of conditional expression (3) to 0.75. The lower limit is 0.55
It is desirable that

【0024】条件式(4)は第2群の焦点距離と広角端
における全系の焦点距離との比に関し、特に第2群を小
型化するためのものである。条件式(4)の上限値を越
えて、第2群の屈折力が弱くなり過ぎると第2群の変倍
時の移動量が増大し、レンズ系が大型化してしまうので
良くない。また下限値を越えて第2群の屈折力が強くな
り過ぎるとレンズ系の小型化においては有利であるが、
第2群からの収差の発生量が増大しすぎて、これを第1
群で補正しきれなくなるため良くない。
Conditional expression (4) relates to the ratio between the focal length of the second lens unit and the focal length of the entire system at the wide-angle end, and is particularly for downsizing the second lens unit. If the upper limit of conditional expression (4) is exceeded and the refractive power of the second lens unit becomes too weak, the amount of movement of the second lens unit during zooming increases, and the lens system becomes large, which is not good. Further, if the refractive power of the second lens unit becomes too strong below the lower limit, it is advantageous in downsizing the lens system.
Since the amount of aberration generated from the second lens unit increases too much,
It is not good because the group can no longer correct.

【0025】第1発明において更に光学性能と小型化を
バランス良く保つためには、条件式(4)の上限値を
0.75とすることが望ましい。また下限値を0.55
とすることが望ましい。
In the first aspect of the present invention, in order to maintain a good balance between optical performance and miniaturization, it is desirable to set the upper limit of conditional expression (4) to 0.75. The lower limit is 0.55
It is desirable that

【0026】尚、第1発明において第2群の負の第22
レンズを2つ以上の負のレンズに分割して構成しても良
い。
Incidentally, in the first invention, the negative 22nd element of the 2nd group
The lens may be divided into two or more negative lenses.

【0027】次に第2発明の特徴について説明する。Next, the features of the second invention will be described.

【0028】第2発明としての実施形態では、前述の如
く第1群は物体側へ凸面を向けたメニスカス状の正の第
11レンズと負の第12レンズ、少なくとも1つの非球
面を有した負の第13レンズそして正の第14レンズよ
り成り、該第2群は少なくとも1つの非球面を有し像面
側に凸面を向けた正の第21レンズ、負の第22レンズ
を有し、該第13レンズと第21レンズの材質のアッベ
数を各々前述の条件式(1),(2)を満足するように
している。
In the embodiment as the second invention, as described above, the first lens unit has a positive meniscus eleventh lens element having a convex surface facing the object side and a negative twelfth lens element, and a negative lens element having at least one aspherical surface. And a positive 14th lens, wherein the second group has at least one aspherical surface, has a positive 21st lens with a convex surface facing the image side, and a negative 22nd lens, The Abbe numbers of the materials of the thirteenth lens and the twenty-first lens are made to satisfy the above-mentioned conditional expressions (1) and (2), respectively.

【0029】第2発明における第1群と第2群の基本構
成及び第13レンズと第21レンズに非球面を用いたこ
とによる効果等は、前述した第1発明と同じである。
The basic structure of the first and second groups in the second invention and the effects of using aspherical surfaces for the thirteenth lens and the twenty-first lens are the same as those of the first invention described above.

【0030】第2発明では第13レンズと第21レンズ
の材質のアッベ数を条件式(1),(2)を満足するよ
うにし、これにより主に変倍に伴い変動する色収差を良
好に補正している。
In the second invention, the Abbe numbers of the materials of the thirteenth lens and the twenty-first lens are made to satisfy the conditional expressions (1) and (2), so that the chromatic aberration mainly fluctuating due to the magnification change is well corrected. doing.

【0031】次に、前記の条件式(1),(2)の技術
的意味について説明する。
Next, the technical meaning of the conditional expressions (1) and (2) will be described.

【0032】条件式(1)は第13レンズの材質のアッ
ベ数に関し、主に望遠端における倍率色収差を良好に補
正するためのものである。上限値を越えてアッベ数が大
きくなる、即ち分散が小さくなると主に望遠端の倍率色
収差が増大する。また第13レンズは非球面を有してお
り、広角端におけるコマ収差を良好に補正しつつ望遠端
の倍率色収差を良好に補正可能なレンズ形状を設定する
ことが困難となるので良くない。
Conditional expression (1) relates to the Abbe number of the material of the thirteenth lens, and is mainly for favorably correcting lateral chromatic aberration at the telephoto end. If the Abbe's number becomes large beyond the upper limit, that is, the dispersion becomes small, the chromatic aberration of magnification mainly at the telephoto end increases. Further, the thirteenth lens has an aspherical surface, and it is difficult to set a lens shape that can satisfactorily correct coma at the wide-angle end and satisfactorily correct lateral chromatic aberration at the telephoto end.

【0033】条件式(2)は第21レンズの材質のアッ
ベ数に関し、主に変倍における軸上色収差の変動を抑制
するためのものである。上限値を越えてアッベ数が大き
くなる、即ち分散が小さくなると特に望遠端における軸
上色収差がオーバーになる傾向があり、変倍における軸
上色収差の変動幅が増大し良くない。
Conditional expression (2) relates to the Abbe number of the material of the twenty-first lens, and is mainly for suppressing the fluctuation of the axial chromatic aberration at the time of zooming. If the Abbe's number becomes larger than the upper limit, that is, the dispersion becomes small, the axial chromatic aberration tends to become excessive, especially at the telephoto end, and the fluctuation range of the axial chromatic aberration at the time of zooming increases, which is not good.

【0034】尚、第2発明において第2群の負の第22
レンズを2つ以上の負のレンズに分割して構成しても良
い。
In the second invention, the negative 22nd lens of the second group is used.
The lens may be divided into two or more negative lenses.

【0035】第1発明と第2発明は以上のようにレンズ
構成を特定することにより小型で諸収差を良好に補正し
たズームレンズを達成しているが、第1発明、第2発明
において更に高い光学性能を得るためには、下記の条件
のうち少なくとも1つを満足することが望ましい。
The first invention and the second invention achieve a zoom lens which is compact and has various aberrations favorably corrected by specifying the lens configuration as described above. However, the first and second inventions are still higher. In order to obtain optical performance, it is desirable to satisfy at least one of the following conditions.

【0036】(a1)前記第12レンズの材質のアッベ
数をν12、前記第22レンズの材質の屈折率をN22
とするとき、 30<ν12 ・・・・・・・・(5) N22<1.75 ・・・・・・(6) なる条件を満足することである。
(A1) The Abbe number of the material of the twelfth lens is ν12, and the refractive index of the material of the twenty-second lens is N22.
Then, it is to satisfy the condition of 30 <ν12 ... (5) N22 <1.75 (6).

【0037】条件式(5)は負の屈折力を有する第12
レンズの材質のアッベ数を規定している。条件式(5)
の下限値を越えてアッベ数が小さく、即ち分散が大きく
なると広角端における倍率色収差が増大し、これを他の
レンズで補正しようとしたとき軸上色収差と倍率色収差
とのバランスが崩れ、全変倍領域で良好な収差補正が困
難になってくるため良くない。
The conditional expression (5) is the twelfth conditional expression having negative refractive power.
It defines the Abbe number of the lens material. Conditional expression (5)
If the Abbe's number is smaller than the lower limit of, that is, if the dispersion is large, the chromatic aberration of magnification at the wide-angle end increases, and when trying to correct this with other lenses, the balance between axial chromatic aberration and chromatic aberration of magnification is lost, and total variation occurs. This is not good because it becomes difficult to correct aberrations well in the double range.

【0038】条件式(6)は負の屈折力を有する第22
レンズの材質の屈折率を規定するためのものであり、主
に軸外収差の補正とともにローコスト化を実現するため
のものである。前述したように比較的レンズ外径が大き
いために諸収差の発生が多く、またレンズの材質単価に
よりレンズコストに大きく影響する。そのため条件式
(6)の上限値を越えて第22レンズの材質の屈折率が
増大すると軸外収差が大きくなり、またレンズコストが
増大するため良くない。
The conditional expression (6) is the 22nd condition which has a negative refractive power.
This is for defining the refractive index of the material of the lens, and mainly for correcting the off-axis aberration and realizing the cost reduction. As described above, since the lens outer diameter is relatively large, various aberrations occur frequently, and the unit cost of the lens material greatly affects the lens cost. Therefore, if the refractive index of the material of the 22nd lens increases beyond the upper limit of conditional expression (6), off-axis aberrations increase and the lens cost increases, which is not good.

【0039】更には条件式(6)の上限値を1.72と
することが諸収差の補正及びレンズ系全体の小型化のた
めに好ましい。
Furthermore, it is preferable to set the upper limit of conditional expression (6) to 1.72 in order to correct various aberrations and reduce the size of the entire lens system.

【0040】(a2)前記第12レンズの物体側と像面
側のレンズ面の曲率半径を各々R3,R4としたとき、 −4<(R3+R4)/(R3−R4)<−0.1 ・・・・・・(7) なる条件を満足することである。
(A2) -4 <(R3 + R4) / (R3-R4) <-0.1, where R3 and R4 are the radii of curvature of the object-side and image-side lens surfaces of the twelfth lens, respectively. (7) To satisfy the following condition.

【0041】条件式(7)は第12レンズのレンズ形状
を規定するものであり、主に球面収差とコマ収差とを同
時に良好に補正するためのものである。条件式(7)の
下限値を越えるとメニスカス形状が強くなり、球面収差
が補正不足になる傾向があり、特に広角端における球面
収差がアンダーとなるため良くない。また上限値を越え
ると負の屈折力が強くなり、球面収差が補正過剰となる
傾向にあると共にコマ収差を良好に補正することが困難
となるため良くない。
Conditional expression (7) defines the lens shape of the twelfth lens, and is mainly for favorably correcting spherical aberration and coma at the same time. If the lower limit of conditional expression (7) is exceeded, the meniscus shape tends to be strong, and spherical aberration tends to be undercorrected. On the other hand, when the value exceeds the upper limit, the negative refractive power becomes strong, the spherical aberration tends to be overcorrected, and it becomes difficult to satisfactorily correct the coma aberration, which is not preferable.

【0042】更に小型化を維持しつつ球面収差とコマ収
差を良好に補正するためには、条件式(7)の下限値を
−2にすることが好ましい。また上限値を−0.2にす
ることが好ましい。
In order to satisfactorily correct spherical aberration and coma while maintaining downsizing, it is preferable to set the lower limit of conditional expression (7) to -2. Further, it is preferable that the upper limit value is -0.2.

【0043】(a3)前記第12レンズと第13レンズ
との空気間隔をD4、前記第13レンズと第14レンズ
との空気間隔をD6としたとき、 0.02<D4/D6<3.0 ・・・・・・(8) なる条件を満足することである。
(A3) When the air gap between the twelfth lens and the thirteenth lens is D4 and the air gap between the thirteenth lens and the fourteenth lens is D6, 0.02 <D4 / D6 <3.0 --- (8) To satisfy the following condition.

【0044】条件式(8)は非球面を有する第13レン
ズの前後のレンズとの軸上空気間隔の比に関し、主に球
面収差とコマ収差を全変倍領域において良好に補正する
と共に第1群の小型化を実現するためのものである。条
件式(8)の上限値を越えて第13レンズと第14レン
ズとの軸上空気間隔が小さくなり過ぎると球面収差を良
好に補正することができるが、コマ収差を良好に補正す
ることが困難となるため良くない。また下限値を越えて
第13レンズと第12レンズとの軸上空気間隔が小さく
なり過ぎると逆にコマ収差を良好に補正することができ
るが、球面収差が補正過剰となるため良くない。
Conditional expression (8) relates to the ratio of the axial air distance between the front and rear lenses of the thirteenth lens having an aspherical surface, and mainly corrects spherical aberration and coma favorably in the entire zoom range and This is for realizing the miniaturization of the group. If the axial air distance between the thirteenth lens and the fourteenth lens becomes too small beyond the upper limit of conditional expression (8), spherical aberration can be corrected well, but coma can be corrected well. Not good because it becomes difficult. On the other hand, if the axial air distance between the thirteenth lens and the twelfth lens becomes too small below the lower limit, coma aberration can be corrected well, but spherical aberration is overcorrected, which is not good.

【0045】更に球面収差とコマ収差をバランス良く補
正するためには、条件式(8)の上限値を2.0にする
ことが好ましい。また下限値を0.06とすることが好
ましい。
Further, in order to correct spherical aberration and coma in a well-balanced manner, it is preferable to set the upper limit of conditional expression (8) to 2.0. Further, it is preferable that the lower limit value is 0.06.

【0046】(a4)前記第14レンズの物体側と像面
側のレンズ面の曲率半径を各々R7,R8としたとき、 0.2<(R7+R8)/(R7−R8)<1.0 ・・・・・・(9) なる条件を満足することである。
(A4) 0.2 <(R7 + R8) / (R7-R8) <1.0, where R7 and R8 are the radii of curvature of the object-side and image-side lens surfaces of the fourteenth lens, respectively. (9) It is to satisfy the following condition.

【0047】条件式(9)は第14レンズのレンズ形状
を規定するものであり、主に球面収差と像面特性を良好
に補正するためのものである。条件式(9)の上限値を
越えると第14レンズの屈折力が強くなり過ぎて像面特
性は良好に補正することができるが、球面収差量が増大
するため良くない。また下限値を越えると第14レンズ
の屈折力が弱くなり過ぎて球面収差の発生量は抑えられ
るものの、像面特性が悪化し、また第1群が大型化する
傾向にあるため良くない。
Conditional expression (9) defines the lens shape of the fourteenth lens, and is mainly for favorably correcting the spherical aberration and the image surface characteristic. If the upper limit of conditional expression (9) is exceeded, the refracting power of the fourteenth lens becomes too strong, and the image surface characteristics can be corrected well, but this is not good because the amount of spherical aberration increases. On the other hand, when the value goes below the lower limit, the refracting power of the fourteenth lens becomes too weak and the amount of spherical aberration generated can be suppressed, but the image surface characteristics are deteriorated and the first group tends to be large, which is not preferable.

【0048】更に球面収差と像面特性をバランス良く補
正するためには、条件式(9)の下限値を0.4にする
ことが好ましい。
Further, in order to correct spherical aberration and image plane characteristics in a well-balanced manner, it is preferable to set the lower limit of conditional expression (9) to 0.4.

【0049】次に本発明の数値実施例を示す。数値実施
例においてRiは物体側より順に第i番目のレンズ面の
曲率半径、Diは物体側より第i番目のレンズ厚及び空
気間隔、Niとνiは各々物体側より順に第i番目のレ
ンズのガラスの屈折率とアッベ数である。
Next, numerical examples of the present invention will be described. In the numerical examples, Ri is the radius of curvature of the i-th lens surface in order from the object side, Di is the i-th lens thickness and air spacing from the object side, and Ni and νi are the i-th lens surfaces in order from the object side. The refractive index and Abbe number of glass.

【0050】非球面形状は光軸方向にX軸、光軸と垂直
方向にH軸、光の進行方向を正としRを近軸曲率半径、
A,B,C,D,Eを各々非球面係数としたとき、
The aspherical shape has an X axis in the optical axis direction, an H axis in a direction perpendicular to the optical axis, a positive light traveling direction, and R as a paraxial radius of curvature.
When A, B, C, D and E are aspherical coefficients,

【0051】[0051]

【数1】 なる式で表わしている。又前述の各条件式と数値実施例
における諸数値との関係を表−1に示す。
[Equation 1] It is represented by the following equation. Table 1 shows the relationship between the above-described conditional expressions and various numerical values in the numerical examples.

【0052】(数値実施例1) F= 30.83〜 58.58 FNO= 4.80 〜 9.12 2ω= 70.1°〜40.5° R 1= 17.14 D 1= 1.70 N 1=1.48749 ν 1= 70.2 R 2= 23.84 D 2= 1.18 R 3= -48.81 D 3= 1.10 N 2=1.83400 ν 2= 37.2 R 4= 84.11 D 4= 0.25 R 5= 28.24 D 5= 1.50 N 3=1.58306 ν 3= 30.2 R 6= 21.83 D 6= 2.87 R 7= 41.14 D 7= 3.30 N 4=1.48749 ν 4= 70.2 R 8= -9.26 D 8=可変 R 9= -41.36 D 9= 2.30 N 5=1.58306 ν 5= 30.2 R10= -29.40 D10= 5.27 R11= -10.21 D11= 1.20 N 6=1.65844 ν 6= 50.9 R12= -59.04Numerical Example 1 F = 30.83 to 58.58 FNO = 4.80 to 9.12 2ω = 70.1 ° to 40.5 ° R 1 = 17.14 D 1 = 1.70 N 1 = 1.48749 ν 1 = 70.2 R 2 = 23.84 D 2 = 1.18 R 3 = -48.81 D 3 = 1.10 N 2 = 1.83400 ν 2 = 37.2 R 4 = 84.11 D 4 = 0.25 R 5 = 28.24 D 5 = 1.50 N 3 = 1.58306 ν 3 = 30.2 R 6 = 21.83 D 6 = 2.87 R 7 = 41.14 D 7 = 3.30 N 4 = 1.48749 ν 4 = 70.2 R 8 = -9.26 D 8 = Variable R 9 = -41.36 D 9 = 2.30 N 5 = 1.58306 ν 5 = 30.2 R10 = -29.40 D10 = 5.27 R11 = -10.21 D11 = 1.20 N 6 = 1.65844 ν 6 = 50.9 R12 = -59.04

【0053】[0053]

【表1】 非球面係数 5面:A= 0 B=-2.919e-04 C=-2.785e-06 D=-1.031e-07 E= 0 9面:A= 0 B= 4.703e-05 C= 5.309e-07 D=-2.394e-09 E= 2.487e-11 (数値実施例2) F= 32.22〜 60.97 FNO= 4.00 〜 7.57 2ω= 67.8°〜39.1° R 1= 15.60 D 1= 1.70 N 1=1.57500 ν 1= 41.5 R 2= 29.37 D 2= 1.03 R 3= -23.42 D 3= 1.20 N 2=1.85025 ν 2= 32.3 R 4= 101.19 D 4= 0.84 R 5= -53.95 D 5= 1.40 N 3=1.58306 ν 3= 30.2 R 6= -42.27 D 6= 1.33 R 7= 50.66 D 7= 3.20 N 4=1.48749 ν 4= 70.2 R 8= -9.41 D 8=可変 R 9= -45.54 D 9= 2.50 N 5=1.58306 ν 5= 30.2 R10= -31.47 D10= 5.70 R11= -10.17 D11= 1.20 N 6=1.69679 ν 6= 55.5 R12= -46.71[Table 1] Aspheric coefficient 5 surface: A = 0 B = -2.919e-04 C = -2.785e-06 D = -1.031e-07 E = 0 9 surface: A = 0 B = 4.703e-05 C = 5.309e- 07 D = -2.394e-09 E = 2.487e-11 (Numerical example 2) F = 32.22 to 60.97 FNO = 4.00 to 7.57 2 ω = 67.8 ° to 39.1 ° R 1 = 15.60 D 1 = 1.70 N 1 = 1.57500 ν 1 = 41.5 R 2 = 29.37 D 2 = 1.03 R 3 = -23.42 D 3 = 1.20 N 2 = 1.85025 ν 2 = 32.3 R 4 = 101.19 D 4 = 0.84 R 5 = -53.95 D 5 = 1.40 N 3 = 1.58306 ν 3 = 30.2 R 6 = -42.27 D 6 = 1.33 R 7 = 50.66 D 7 = 3.20 N 4 = 1.48749 ν 4 = 70.2 R 8 = -9.41 D 8 = variable R 9 = -45.54 D 9 = 2.50 N 5 = 1.58306 ν 5 = 30.2 R10 = -31.47 D10 = 5.70 R11 = -10.17 D11 = 1.20 N 6 = 1.69679 ν 6 = 55.5 R12 = -46.71

【0054】[0054]

【表2】 非球面係数 5面:A= 0 B=-2.921e-04 C=-2.432e-06 D=-7.616e-08 E= 0 9面:A= 0 B= 6.229e-05 C= 3.442e-07 D= 2.362e-09 E=-6.326e-12 (数値実施例3) F= 35.00〜 70.00 FNO= 4.30 〜 8.60 2ω= 63.4°〜34.4° R 1= 15.01 D 1= 1.60 N 1=1.48749 ν 1= 70.2 R 2= 27.40 D 2= 0.88 R 3= -23.56 D 3= 1.10 N 2=1.80609 ν 2= 41.0 R 4= 75.30 D 4= 0.52 R 5= -69.29 D 5= 1.40 N 3=1.58306 ν 3= 30.2 R 6= -50.27 D 6= 1.32 R 7= 41.17 D 7= 3.60 N 4=1.48749 ν 4= 70.2 R 8= -9.55 D 8=可変 R 9= -91.98 D 9= 2.30 N 5=1.58306 ν 5= 30.2 R10= -63.38 D10= 6.13 R11= -9.61 D11= 1.20 N 6=1.63853 ν 6= 55.4 R12= -38.71[Table 2] Aspheric coefficient 5 surface: A = 0 B = -2.921e-04 C = -2.432e-06 D = -7.616e-08 E = 0 9 surface: A = 0 B = 6.229e-05 C = 3.442e- 07 D = 2.362e-09 E = -6.326e-12 (Numerical example 3) F = 35.00 to 70.00 FNO = 4.30 to 8.60 2ω = 63.4 ° to 34.4 ° R 1 = 15.01 D 1 = 1.60 N 1 = 1.48749 ν 1 = 70.2 R 2 = 27.40 D 2 = 0.88 R 3 = -23.56 D 3 = 1.10 N 2 = 1.80609 ν 2 = 41.0 R 4 = 75.30 D 4 = 0.52 R 5 = -69.29 D 5 = 1.40 N 3 = 1.58306 ν 3 = 30.2 R 6 = -50.27 D 6 = 1.32 R 7 = 41.17 D 7 = 3.60 N 4 = 1.48749 ν 4 = 70.2 R 8 = -9.55 D 8 = variable R 9 = -91.98 D 9 = 2.30 N 5 = 1.58306 ν 5 = 30.2 R10 = -63.38 D10 = 6.13 R11 = -9.61 D11 = 1.20 N 6 = 1.63853 ν 6 = 55.4 R12 = -38.71

【0055】[0055]

【表3】 非球面係数 5面:A= 0 B=-2.859e-04 C=-1.942e-06 D=-9.183e-08 E= 0 9面:A= 0 B= 6.578e-05 C= 2.423e-07 D= 2.289e-09 E= 1.538e-11 (数値実施例4) F= 39.01〜 78.00 FNO= 4.00 〜 8.00 2ω= 58.0°〜31.0° R 1= 16.12 D 1= 1.70 N 1=1.51633 ν 1= 64.2 R 2= 30.38 D 2= 0.91 R 3= -30.10 D 3= 1.40 N 2=1.83400 ν 2= 37.2 R 4= 5005.00 D 4= 0.97 R 5= -50.73 D 5= 1.50 N 3=1.58306 ν 3= 30.2 R 6= -68.41 D 6= 1.71 R 7= 63.71 D 7= 3.50 N 4=1.48749 ν 4= 70.2 R 8= -10.79 D 8=可変 R 9= -39.28 D 9= 2.30 N 5=1.58306 ν 5= 30.2 R10= -30.56 D10= 5.36 R11= -9.38 D11= 1.20 N 6=1.62299 ν 6= 58.1 R12= -40.10[Table 3] Aspheric coefficient 5 surface: A = 0 B = -2.859e-04 C = -1.942e-06 D = -9.183e-08 E = 0 9 surface: A = 0 B = 6.578e-05 C = 2.423e- 07 D = 2.289e-09 E = 1.538e-11 (Numerical example 4) F = 39.01 to 78.00 FNO = 4.00 to 8.00 2 ω = 58.0 ° to 31.0 ° R 1 = 16.12 D 1 = 1.70 N 1 = 1.51633 ν 1 = 64.2 R 2 = 30.38 D 2 = 0.91 R 3 = -30.10 D 3 = 1.40 N 2 = 1.83400 ν 2 = 37.2 R 4 = 5005.00 D 4 = 0.97 R 5 = -50.73 D 5 = 1.50 N 3 = 1.58306 ν 3 = 30.2 R 6 = -68.41 D 6 = 1.71 R 7 = 63.71 D 7 = 3.50 N 4 = 1.48749 ν 4 = 70.2 R 8 = -10.79 D 8 = Variable R 9 = -39.28 D 9 = 2.30 N 5 = 1.58306 ν 5 = 30.2 R10 = -30.56 D10 = 5.36 R11 = -9.38 D11 = 1.20 N 6 = 1.62299 ν 6 = 58.1 R12 = -40.10

【0056】[0056]

【表4】 非球面係数 5面:A= 0 B=-1.966e-04 C=-8.022e-07 D=-4.175e-08 E= 0 9面:A= 0 B= 7.637e-05 C=-5.128e-08 D= 1.980e-08 E=-1.481e-10 (数値実施例5) F= 39.00〜 90.03 FNO= 4.00 〜 9.23 2ω= 58.0°〜27.0° R 1= 15.01 D 1= 1.70 N 1=1.51633 ν 1= 64.2 R 2= 29.84 D 2= 0.91 R 3= -28.04 D 3= 1.10 N 2=1.83400 ν 2= 37.2 R 4= 1416.68 D 4= 0.79 R 5= -43.67 D 5= 1.50 N 3=1.58306 ν 3= 30.2 R 6= -53.66 D 6= 1.49 R 7= 82.63 D 7= 3.45 N 4=1.48749 ν 4= 70.2 R 8= -10.69 D 8=可変 R 9= -46.66 D 9= 2.30 N 5=1.58306 ν 5= 30.2 R10= -26.59 D10= 4.74 R11= -10.33 D11= 1.20 N 6=1.71299 ν 6= 53.8 R12= -47.85[Table 4] Aspheric coefficient 5 surface: A = 0 B = -1.966e-04 C = -8.022e-07 D = -4.175e-08 E = 0 9 surface: A = 0 B = 7.637e-05 C = -5.128e -08 D = 1.980e-08 E = -1.481e-10 (Numerical example 5) F = 39.00 to 90.03 FNO = 4.00 to 9.23 2ω = 58.0 ° to 27.0 ° R 1 = 15.01 D 1 = 1.70 N 1 = 1.51633 ν 1 = 64.2 R 2 = 29.84 D 2 = 0.91 R 3 = -28.04 D 3 = 1.10 N 2 = 1.83400 ν 2 = 37.2 R 4 = 1416.68 D 4 = 0.79 R 5 = -43.67 D 5 = 1.50 N 3 = 1.58306 ν 3 = 30.2 R 6 = -53.66 D 6 = 1.49 R 7 = 82.63 D 7 = 3.45 N 4 = 1.48749 ν 4 = 70.2 R 8 = -10.69 D 8 = variable R 9 = -46.66 D 9 = 2.30 N 5 = 1.58306 ν 5 = 30.2 R10 = -26.59 D10 = 4.74 R11 = -10.33 D11 = 1.20 N 6 = 1.71299 ν 6 = 53.8 R12 = -47.85

【0057】[0057]

【表5】 非球面係数 5面:A= 0 B=-2.024e-04 C=-6.460e-07 D=-3.974e-08 E= 0 6面:A= 0 B= 8.465e-07 C=-7.234e-09 D=-1.402e-10 E= 0 9面:A= 0 B= 7.449e-05 C=-3.587e-07 D= 1.666e-08 E=-1.142e-10 (数値実施例6) F= 36.12〜 67.94 FNO= 4.60 〜 8.65 2ω= 61.8°〜35.3° R 1= 18.57 D 1= 1.90 N 1=1.48749 ν 1= 70.2 R 2= 47.22 D 2= 1.18 R 3= -27.11 D 3= 1.30 N 2=1.83400 ν 2= 37.2 R 4= -117.58 D 4= 3.26 R 5= -57.35 D 5= 1.60 N 3=1.58306 ν 3= 30.2 R 6= -89.34 D 6= 1.84 R 7= 39.39 D 7= 3.00 N 4=1.48749 ν 4= 70.2 R 8= -12.72 D 8=可変 R 9= -67.81 D 9= 2.30 N 5=1.58306 ν 5= 30.2 R10= -56.06 D10= 6.23 R11= -9.78 D11= 1.20 N 6=1.63853 ν 6= 55.4 R12= -42.03[Table 5] Aspheric coefficient 5 surface: A = 0 B = -2.024e-04 C = -6.460e-07 D = -3.974e-08 E = 0 6 surface: A = 0 B = 8.465e-07 C = -7.234e -09 D = -1.402e-10 E = 0 9 side: A = 0 B = 7.449e-05 C = -3.587e-07 D = 1.666e-08 E = -1.142e-10 (Numerical example 6) F = 36.12 to 67.94 FNO = 4.60 to 8.65 2ω = 61.8 ° to 35.3 ° R 1 = 18.57 D 1 = 1.90 N 1 = 1.48749 ν 1 = 70.2 R 2 = 47.22 D 2 = 1.18 R 3 = -27.11 D 3 = 1.30 N 2 = 1.83400 ν 2 = 37.2 R 4 = -117.58 D 4 = 3.26 R 5 = -57.35 D 5 = 1.60 N 3 = 1.58306 ν 3 = 30.2 R 6 = -89.34 D 6 = 1.84 R 7 = 39.39 D 7 = 3.00 N 4 = 1.48749 ν 4 = 70.2 R 8 = -12.72 D 8 = Variable R 9 = -67.81 D 9 = 2.30 N 5 = 1.58306 ν 5 = 30.2 R10 = -56.06 D10 = 6.23 R11 = -9.78 D11 = 1.20 N 6 = 1.63853 ν 6 = 55.4 R12 = -42.03

【0058】[0058]

【表6】 非球面係数 5面:A= 0 B=-1.243e-04 C=-1.019e-06 D=-2.104e-09 E= 0 9面:A= 0 B= 6.242e-05 C= 5.064e-08 D= 9.440e-09 E=-6.200e-11[Table 6] Aspheric coefficient 5 surface: A = 0 B = -1.243e-04 C = -1.019e-06 D = -2.104e-09 E = 0 9 surface: A = 0 B = 6.242e-05 C = 5.064e- 08 D = 9.440e-09 E = -6.200e-11

【0059】[0059]

【表7】 [Table 7]

【0060】[0060]

【発明の効果】本発明によれば以上のように、所謂2群
のズームレンズにおいて、各レンズ群のレンズ構成を適
切に設定するとともに非球面及びそれを用いるレンズの
材質を適切に設定することにより、変倍比2程度で広画
角を有しつつ、レンズ全長の短縮化を図った全変倍範囲
にわたり高い光学性能を有した小型のズームレンズを達
成することができる。
As described above, according to the present invention, in the so-called two-group zoom lens, the lens configuration of each lens group is appropriately set, and the aspherical surface and the material of the lens using the same are appropriately set. As a result, it is possible to achieve a compact zoom lens having a wide angle of view with a zoom ratio of about 2 and a high optical performance over the entire zoom range with a shortened overall lens length.

【図面の簡単な説明】[Brief description of drawings]

【図1】 本発明の数値実施例1の広角端のレンズ断面
FIG. 1 is a lens cross-sectional view at a wide-angle end according to Numerical Example 1 of the present invention.

【図2】 本発明の数値実施例2の広角端のレンズ断面
FIG. 2 is a lens cross-sectional view at a wide-angle end according to Numerical Example 2 of the present invention.

【図3】 本発明の数値実施例3の広角端のレンズ断面
FIG. 3 is a lens cross-sectional view at a wide-angle end according to Numerical Example 3 of the present invention.

【図4】 本発明の数値実施例4の広角端のレンズ断面
FIG. 4 is a lens cross-sectional view at a wide-angle end according to Numerical Example 4 of the present invention.

【図5】 本発明の数値実施例5の広角端のレンズ断面
FIG. 5 is a lens cross-sectional view at a wide-angle end according to Numerical Example 5 of the present invention.

【図6】 本発明の数値実施例6の広角端のレンズ断面
FIG. 6 is a lens cross-sectional view at a wide-angle end according to Numerical Example 6 of the present invention.

【図7】 本発明の数値実施例1の広角端の収差図FIG. 7 is an aberration diagram at a wide-angle end according to Numerical Example 1 of the present invention.

【図8】 本発明の数値実施例1の中間の収差図FIG. 8 is an intermediate aberration diagram of Numerical example 1 of the present invention.

【図9】 本発明の数値実施例1の望遠端の収差図FIG. 9 is an aberration diagram at a telephoto end according to Numerical Example 1 of the present invention.

【図10】 本発明の数値実施例2の広角端の収差図FIG. 10 is an aberration diagram at a wide-angle end according to Numerical Example 2 of the present invention.

【図11】 本発明の数値実施例2の中間の収差図FIG. 11 is an intermediate aberration diagram of Numerical example 2 of the present invention.

【図12】 本発明の数値実施例2の望遠端の収差図FIG. 12 is an aberration diagram at a telephoto end according to Numerical Example 2 of the present invention.

【図13】 本発明の数値実施例3の広角端の収差図FIG. 13 is an aberration diagram at the wide-angle end according to Numerical Example 3 of the present invention.

【図14】 本発明の数値実施例3の中間の収差図FIG. 14 is an intermediate aberration diagram of Numerical Example 3 of the present invention.

【図15】 本発明の数値実施例3の望遠端の収差図FIG. 15 is an aberration diagram at a telephoto end according to Numerical Example 3 of the present invention.

【図16】 本発明の数値実施例4の広角端の収差図FIG. 16 is an aberration diagram at a wide-angle end according to Numerical Example 4 of the present invention.

【図17】 本発明の数値実施例4の中間の収差図FIG. 17 is an intermediate aberration diagram of Numerical Example 4 of the present invention.

【図18】 本発明の数値実施例4の望遠端の収差図FIG. 18 is an aberration diagram at a telephoto end according to Numerical Example 4 of the present invention.

【図19】 本発明の数値実施例5の広角端の収差図FIG. 19 is an aberration diagram at a wide-angle end according to Numerical Example 5 of the present invention.

【図20】 本発明の数値実施例5の中間の収差図FIG. 20 is an intermediate aberration diagram of Numerical example 5 of the present invention.

【図21】 本発明の数値実施例5の望遠端の収差図FIG. 21 is an aberration diagram at a telephoto end according to Numerical Example 5 of the present invention.

【図22】 本発明の数値実施例6の広角端の収差図FIG. 22 is an aberration diagram at a wide-angle end according to Numerical Example 6 of the present invention.

【図23】 本発明の数値実施例6の中間の収差図FIG. 23 is an intermediate aberration diagram of Numerical Example 6 of the present invention.

【図24】 本発明の数値実施例6の望遠端の収差図FIG. 24 is an aberration diagram at a telephoto end according to Numerical Example 6 of the present invention.

【符号の説明】[Explanation of symbols]

L1 第1群 L2 第2群 IP 像面 d d線 g g線 S サジタル像面 M メリディオナル像面 S.C 正弦条件 h 像高 L1 1st group L2 2nd group IP Image plane d d line g g line S Sagittal image plane M Meridional image plane S C Sine condition h Image height

Claims (7)

【特許請求の範囲】[Claims] 【請求項1】 物体側より順に正の屈折力の第1群と負
の屈折力の第2群の2つのレンズ群を有し、両レンズ群
の間隔を変えて変倍を行う小型のズームレンズにおい
て、該第1群は物体側へ凸面を向けたメニスカス状の正
の第11レンズと負の第12レンズとプラスチック材よ
り成り、少なくとも1つの非球面を有した負の第13レ
ンズそして正の第14レンズより成り、該第2群は像面
側に凸面を向けたプラスチック材より成り、少なくとも
1つの非球面を有した正の第21レンズと像面側に凸面
を向けたメニスカス状の負の第22レンズを有している
ことを特徴とする小型のズームレンズ。
1. A compact zoom lens system having two lens units, a first lens unit having a positive refractive power and a second lens unit having a negative refractive power, which are arranged in order from the object side, and performing zooming by changing the distance between both lens units. In the lens, the first group is composed of a meniscus-shaped positive eleventh lens having a convex surface directed toward the object side, a negative twelfth lens, and a plastic material, and a negative thirteenth lens having at least one aspherical surface and a positive thirteenth lens. The second lens unit is made of a plastic material having a convex surface directed toward the image side, and has a positive 21st lens having at least one aspherical surface, and a meniscus-shaped lens having a convex surface directed toward the image surface. A small zoom lens having a negative 22nd lens.
【請求項2】 前記第i群の焦点距離をfi、広角端に
おける全系の焦点距離をfwとするとき、 0.5<f1/fw<0.9 0.5<|f2/fw|<0.9 なる条件を満足することを特徴とする請求項1の小型の
ズームレンズ。
2. When the focal length of the i-th group is fi and the focal length of the entire system at the wide-angle end is fw, 0.5 <f1 / fw <0.9 0.5 <| f2 / fw | < The compact zoom lens according to claim 1, wherein the condition of 0.9 is satisfied.
【請求項3】 物体側より順に正の屈折力の第1群と負
の屈折力の第2群の2つのレンズ群を有し、両レンズ群
の間隔を変えて変倍を行う小型のズームレンズにおい
て、該第1群は物体側へ凸面を向けたメニスカス状の正
の第11レンズと負の第12レンズ、少なくとも1つの
非球面を有した負の第13レンズそして正の第14レン
ズより成り、該第2群は少なくとも1つの非球面を有し
像面側に凸面を向けた正の第21レンズ、負の第22レ
ンズを有し、該第13レンズと第21レンズの材質のア
ッベ数を各々ν13,ν21とするとき、 ν13<40 ν21<40なる条件を満足することを特徴とする小型
のズームレンズ。
3. A compact zoom having two lens groups, a first lens group having a positive refractive power and a second lens group having a negative refractive power, in order from the object side, and varying the distance between both lens groups to perform zooming. In the lens, the first group includes a meniscus positive eleventh lens having a convex surface directed toward the object side, a negative twelfth lens, a negative thirteenth lens having at least one aspherical surface, and a positive fourteenth lens. The second lens group has at least one aspherical surface and has a positive twenty-first lens element having a convex surface directed toward the image side and a negative twenty-second lens element, and has an Abbe's material of the thirteenth lens element and the twenty-first lens element. A small zoom lens characterized by satisfying the conditions of ν13 <40 ν21 <40, where the numbers are ν13 and ν21, respectively.
【請求項4】 前記第12レンズの材質のアッベ数をν
12、前記第22レンズの材質の屈折率をN22とする
とき、 30<ν12 N22<1.75 なる条件を満足することを特徴とする請求項2又は3の
小型のズームレンズ。
4. The Abbe number of the material of the twelfth lens is ν
12. The compact zoom lens according to claim 2, wherein the condition of 30 <ν12 N22 <1.75 is satisfied when the refractive index of the material of the 22nd lens is N22.
【請求項5】 前記第12レンズの物体側と像面側のレ
ンズ面の曲率半径を各々R3,R4としたとき、 −4<(R3+R4)/(R3−R4)<−0.1 なる条件を満足することを特徴とする請求項4の小型の
ズームレンズ。
5. A condition that -4 <(R3 + R4) / (R3-R4) <-0.1, where R3 and R4 are curvature radii of the object-side and image-side lens surfaces of the twelfth lens, respectively. The small zoom lens according to claim 4, wherein
【請求項6】 前記第12レンズと第13レンズとの空
気間隔をD4、前記第13レンズと第14レンズとの空
気間隔をD6としたとき、 0.02<D4/D6<3.0 なる条件を満足することを特徴とする請求項4又は5の
小型のズームレンズ。
6. When the air gap between the twelfth lens and the thirteenth lens is D4 and the air gap between the thirteenth lens and the fourteenth lens is D6, 0.02 <D4 / D6 <3.0. The compact zoom lens according to claim 4, wherein the condition is satisfied.
【請求項7】 前記第14レンズの物体側と像面側のレ
ンズ面の曲率半径を各々R7,R8としたとき、 0.2<(R7+R8)/(R7−R8)<1.0 なる条件を満足することを特徴とする請求項5又は6の
小型のズームレンズ。
7. A condition that 0.2 <(R7 + R8) / (R7−R8) <1.0, where R7 and R8 are curvature radii of the object-side and image-side lens surfaces of the fourteenth lens, respectively. The small zoom lens according to claim 5 or 6, characterized in that
JP3431596A 1996-01-29 1996-01-29 Compact zoom lens Pending JPH09211325A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3431596A JPH09211325A (en) 1996-01-29 1996-01-29 Compact zoom lens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3431596A JPH09211325A (en) 1996-01-29 1996-01-29 Compact zoom lens

Publications (1)

Publication Number Publication Date
JPH09211325A true JPH09211325A (en) 1997-08-15

Family

ID=12410738

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3431596A Pending JPH09211325A (en) 1996-01-29 1996-01-29 Compact zoom lens

Country Status (1)

Country Link
JP (1) JPH09211325A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6384986B1 (en) 1999-02-02 2002-05-07 Canon Kabushiki Kaisha Zoom lens and optical apparatus having the same
US7310192B2 (en) 2004-11-18 2007-12-18 Nidec Copal Corporation Zoom lens
JP2019191538A (en) * 2018-04-26 2019-10-31 エーエーシー テクノロジーズ ピーティーイー リミテッド Image capturing optical lens
JP2020109469A (en) * 2018-12-31 2020-07-16 エーエーシー テクノロジーズ ピーティーイー リミテッド Imaging optical lens
JP2022037851A (en) * 2020-08-25 2022-03-09 エーエーシー オプティクス (チャンジョウ)カンパニーリミテッド Image capturing optical lens

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6384986B1 (en) 1999-02-02 2002-05-07 Canon Kabushiki Kaisha Zoom lens and optical apparatus having the same
US7310192B2 (en) 2004-11-18 2007-12-18 Nidec Copal Corporation Zoom lens
JP2019191538A (en) * 2018-04-26 2019-10-31 エーエーシー テクノロジーズ ピーティーイー リミテッド Image capturing optical lens
JP2020109469A (en) * 2018-12-31 2020-07-16 エーエーシー テクノロジーズ ピーティーイー リミテッド Imaging optical lens
JP2022037851A (en) * 2020-08-25 2022-03-09 エーエーシー オプティクス (チャンジョウ)カンパニーリミテッド Image capturing optical lens

Similar Documents

Publication Publication Date Title
JP3253405B2 (en) Two-group zoom lens
JP2001194586A (en) Zoom lens and photographing device using the same
JP4819414B2 (en) Zoom lens and imaging apparatus having the same
JPH07253542A (en) Zoom lens
JPH05150161A (en) Variable power lens
JP2001116992A (en) Zoom lens
JPH05241073A (en) Zoom lens
JP3018742B2 (en) Zoom lens
JP3445359B2 (en) Zoom lens
JP3144193B2 (en) Zoom lens
JP3733355B2 (en) Zoom lens
JP3331011B2 (en) Small two-group zoom lens
JPH06294932A (en) Zoom lens
JP3008711B2 (en) Small zoom lens
JPH05188296A (en) Small-sized three-group zoom lens
JPH08179214A (en) Zoom lens
JP2850548B2 (en) Zoom lens
JPH09211325A (en) Compact zoom lens
JP3144192B2 (en) Zoom lens
JPH07333503A (en) Zoom lens
JP2000075205A (en) Zoom lens
JP3008700B2 (en) Zoom lens
JPH06138389A (en) Wide conversion lens and zoom lens using its lens
JP3186388B2 (en) Zoom lens
JPH0527176A (en) Small-sized, bright zoom lens