JP3144191B2 - Zoom lens - Google Patents

Zoom lens

Info

Publication number
JP3144191B2
JP3144191B2 JP32140193A JP32140193A JP3144191B2 JP 3144191 B2 JP3144191 B2 JP 3144191B2 JP 32140193 A JP32140193 A JP 32140193A JP 32140193 A JP32140193 A JP 32140193A JP 3144191 B2 JP3144191 B2 JP 3144191B2
Authority
JP
Japan
Prior art keywords
lens
refractive power
wide
lens unit
angle end
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.)
Expired - Fee Related
Application number
JP32140193A
Other languages
Japanese (ja)
Other versions
JPH07151971A (en
Inventor
隆志 加藤
彰宏 西尾
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 JP32140193A priority Critical patent/JP3144191B2/en
Priority to TW83106377A priority patent/TW258791B/en
Publication of JPH07151971A publication Critical patent/JPH07151971A/en
Priority to US08/735,571 priority patent/US5691851A/en
Application granted granted Critical
Publication of JP3144191B2 publication Critical patent/JP3144191B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】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小型の高変倍で広画角のズ
ームレンズに関し、特に撮影画角の広画角化を図ると共
にレンズ全長（第１レンズ面から像面までの距離）の短
縮化を図った携帯性に優れた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 small zoom lens having a high zoom ratio and a wide angle of view suitable for a lens shutter camera, a video camera, and the like. The present invention relates to a zoom lens which is excellent in portability and has a reduced length (distance from one lens surface to an image surface).

【０００２】[0002]

【従来の技術】最近レンズシャッターカメラ、ビデオカ
メラ等においては、カメラ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求されている。特にレンズ
シャッターカメラは、ズーム駆動用の電気回路などの周
辺技術の発達などにより、ますますカメラの小型化が進
んでおり、それに備わる撮影レンズも高変倍でかつコン
パクトなズームレンズが要求されている。2. Description of the Related Art Recently, in a lens shutter camera, a video camera, and the like, a small zoom lens having a short overall lens length has been demanded with the downsizing of the camera. In particular, lens shutter cameras are becoming smaller and smaller due to the development of peripheral technology such as electric circuits for driving the zoom, and the photographic lenses provided with them are also required to have high zoom ratios and compact zoom lenses. I have.

【０００３】従来、レンズシャッター用のズームレンズ
としては正、負の屈折力の２つのレンズ群より成る所謂
２群ズームレンズが主流であった。この２群ズームレン
ズはレンズ構成及び変倍時の移動機構が簡易なため、カ
メラの小型化及び比較的低コストであるなどの利点があ
る。しかしながら、変倍作用を１つのレンズ群のみで行
なわなくてはならないため、その変倍比は１．６〜２倍
程度であり、無理に変倍比を拡大することはレンズ系の
大型化を招くと同時に、高い光学性能を保つことが困難
になってくる。Conventionally, as a zoom lens for a lens shutter, a so-called two-group zoom lens comprising two lens groups having positive and negative refractive powers has been mainly used. Since the two-unit zoom lens has a simple lens configuration and a moving mechanism at the time of zooming, it has advantages such as downsizing of the camera and relatively low cost. However, since the zooming operation must be performed by only one lens group, the zooming ratio is about 1.6 to 2 times. Forcibly increasing the zooming ratio requires an increase in the size of the lens system. At the same time, it becomes difficult to maintain high optical performance.

【０００４】２群ズームレンズを基礎とし、第１群を正
の屈折力の２つのレンズ群に分離し、全体として正、
正、負の屈折力の３群構成として高変倍化を狙った３群
ズームレンズが、例えば特開平３−２８２４０９号公
報、特開平４−３７８１０号公報、特開平４−７６５１
１号公報等で提案されている。On the basis of a two-unit zoom lens, the first unit is divided into two lens units having a positive refractive power.
A three-unit zoom lens which aims at high zoom ratio as a three-unit configuration having positive and negative refractive powers is disclosed in, for example, JP-A-3-282409, JP-A-4-37810, and JP-A-4-7651.
No. 1 publication and the like.

【０００５】しかしながら、このレンズ群構成で例えば
半画角３５°以上の広画角なズームレンズ系を達成しよ
うとすると変倍時の入射瞳位置の変化が大きくなる。こ
のため、高変倍化を図る際は変倍による収差変動を抑え
ることが大変困難になってくる。However, if an attempt is made to achieve a wide-angle zoom lens system having a half-angle of view of 35 ° or more with this lens group configuration, the change in the position of the entrance pupil during zooming becomes large. For this reason, it is very difficult to suppress aberration fluctuations due to zooming when achieving high zooming.

【０００６】この他、多レンズ群化により広角端の半画
角を３８°程度、変倍比３．５倍程度とし、広画角化及
び高変倍化を図ったズームレンズが、例えば特開平２−
７２３１６号公報、特開平３−２４９６１４号公報で提
案されている。しかしながら、これらのズームレンズ系
は前玉径及びレンズ全長が共に大型であり、コンパクト
カメラの撮影レンズとしては必ずしも十分でない。In addition, a zoom lens having a wide angle of view and a high zoom ratio by increasing the half angle of view at the wide angle end to about 38 ° and the zoom ratio by about 3.5 times by grouping a plurality of lenses is known, for example. Kaihei 2-
No. 72316 and Japanese Patent Application Laid-Open No. 3-249614. However, these zoom lens systems both have a large front lens diameter and a large overall lens length, and are not always sufficient as a photographing lens of a compact camera.

【０００７】特に外部ファインダーを使用するカメラに
適用する際は、広角端時にレンズ鏡筒がファインダーの
撮影視野を覆ってしまうという問題点がある。又、この
結果、ファインダー配置やカメラの形態の制限を与えて
しまうという問題点も生じてくる。In particular, when applied to a camera using an external finder, there is a problem that the lens barrel covers the field of view of the finder at the wide angle end. In addition, as a result, there arises a problem that the arrangement of the viewfinder and the form of the camera are restricted.

【０００８】[0008]

【発明が解決しようとする課題】一般にズームレンズに
おいて各レンズ群の屈折力を強めれば所定の変倍比を得
るための各レンズ群の移動量が少なくなり、レンズ全長
の短縮化を図りつつ高変倍化が可能となる。しかしなが
ら、単に各レンズ群の屈折力を強めると変倍に伴う収差
変動が大きくなり、特に高変倍化及び広画角化を図る際
には全変倍範囲にわたり良好なる光学性能を得るのが難
しくなってくるという問題点がある。Generally, in a zoom lens, if the refractive power of each lens unit is increased, the amount of movement of each lens unit for obtaining a predetermined zoom ratio is reduced, and the overall length of the lens is reduced. High magnification can be achieved. However, if the refractive power of each lens group is simply increased, the aberration variation accompanying zooming increases, and it is necessary to obtain good optical performance over the entire zoom range, especially when aiming for high zooming and a wide angle of view. There is a problem that it becomes difficult.

【０００９】本発明は全体として５つのレンズ群より構
成し、変倍における各レンズ群の移動条件や屈折力等を
適切に設定し、広角端の撮影画角が７４°程度、変倍比
３．５程度の全変倍範囲にわたり高い光学性能を有した
ズームレンズの提供を目的とする。The present invention comprises five lens groups as a whole, and appropriately sets the moving conditions, refractive power, etc. of each lens group during zooming, the photographic field angle at the wide angle end is about 74 °, and the zoom ratio is 3 It is an object of the present invention to provide a zoom lens having high optical performance over the entire zoom range of about 0.5.

【００１０】[0010]

【課題を解決するための手段】本発明のズームレンズは
物体側より順に負の屈折力の第１群、負の屈折力の第２
群、正の屈折力の第３群の３つのレンズ群より成り、広
角端での合成屈折力が正の屈折力の前群そして正の屈折
力の第４群と負の屈折力の第５群の２つのレンズ群より
成る後群とを有し、広角端から望遠端への変倍に際し
て、該第１，第２，第３群は前群の合成屈折力が広角端
に比べて望遠端で弱まるように移動し、該第４，第５群
はそれらの間隔が狭くなるように移動しており、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、第ｉ群の広角端における横倍率をβｉＷ、広角
端と望遠端における前記前群の合成屈折力をφ123W，φ
123T、ズーム比をＺとしたとき、 ０．５＜｜ｆ５／ｆＷ｜＜１．５ ・・・（１） １．１＜β５Ｗ＜１．８ ・・・（２） １．０＜｜ｆ１／ｆＷ｜＜６．０ ・・・（５） １．０＜｜ｆ２／ｆＷ｜＜６．０ ・・・（６） ０．２５＜（φ１２３Ｗ／φ１２３Ｔ）／Ｚ＜０．８ ・・・（７） ０．２５＜β４Ｗ＜０．５５ ・・・（８） ０．１＜ｆ５・（１−β５Ｗ）／ｆＷ＜０．７ ・・・（９） なる条件を満足することを特徴としている。A zoom lens according to the present invention has a first group of negative refractive power and a second group of negative refractive power in order from the object side.
At the wide-angle end, the combined lens unit includes a front lens unit having a positive refractive power, a fourth lens unit having a positive refractive power, and a fifth lens unit having a negative refractive power. And a rear group consisting of two lens groups. In zooming from the wide-angle end to the telephoto end, the first, second, and third groups have a combined refracting power of the front group that is longer than that of the wide-angle end. The fourth and fifth lens units move so as to be weaker at the end, and the distances between the fourth and fifth lens units are reduced. The focal length of the i-th lens unit is fi, the focal length of the entire system at the wide-angle end is fW, The lateral magnification at the wide-angle end of the i-th unit is βiW, and the combined refractive power of the front unit at the wide-angle end and the telephoto end is φ 123W , φ
Assuming 123T and the zoom ratio as Z, 0.5 <| f5 / fW | <1.5 (1) 1.1 <β5W <1.8 (2) 1.0 <| f1 /FW|<6.0 (5) 1.0 <| f2 / fW | <6.0 (6) 0.25 <(φ123W / φ123T) / Z <0.8 (7) 0.25 <β4W <0.55 (8) 0.1 <f5 · (1−β5W) / fW <0.7 (9) I have.

【００１１】[0011]

【実施例】図１は本発明のズームレンズの近軸屈折力配
置の説明図である。図１において（Ａ）は広角端、
（Ｂ）は望遠端を示している。図２〜図４は各々本発明
の数値実施例１〜３の広角端のレンズ断面図である。図
５〜図１３は本発明の数値実施例１〜３の諸収差図であ
る。FIG. 1 is an explanatory diagram of a paraxial refractive power arrangement of a zoom lens according to the present invention. In FIG. 1, (A) is the wide-angle end,
(B) shows the telephoto end. 2 to 4 are lens cross-sectional views at the wide-angle end in Numerical Examples 1 to 3 of the present invention, respectively. FIGS. 5 to 13 are various aberration diagrams of Numerical Examples 1 to 3 of the present invention.

【００１２】図中、ＬＦは正の屈折力の前群、ＬＲは後
群、ＳＰは絞り、ＩＰは像面である。Ｌｉ（ｉ＝１〜
５）は第ｉ群である。矢印は広角側から望遠側への変倍
を行なう際の各レンズ群の移動方向を示している。In the drawing, LF denotes a front group having a positive refractive power, LR denotes a rear group, SP denotes an aperture, and IP denotes an image plane. Li (i = 1 to
5) is the i-th group. Arrows indicate the moving direction of each lens group when zooming from the wide-angle side to the telephoto side.

【００１３】前群ＬＦは負の屈折力の第１群Ｌ１、負の
屈折力の第２群Ｌ２そして正の屈折力の第３群Ｌ３の３
つのレンズ群より成り、広角端での合成屈折力が正の屈
折力となっている。後群ＬＲは正の屈折力の第４群Ｌ４
と負の屈折力の第５群Ｌ５の２つのレンズ群より成って
いる。The front unit LF includes a first unit L1 having a negative refractive power, a second unit L2 having a negative refractive power, and a third unit L3 having a positive refractive power.
It consists of two lens groups, and the combined refractive power at the wide-angle end is a positive refractive power. The rear unit LR is a fourth unit L4 having a positive refractive power.
And a fifth lens unit L5 having a negative refractive power.

【００１４】広角端から望遠端への変倍に際して、第
１，第２，第３群はいずれも物体側へ第２群が他のレン
ズ群との相対的位置関係を変えて移動すると共に、前群
の合成屈折力が広角端に比べて望遠端で弱まるように移
動している。又、第４群と第５群はそれらの間隔が狭く
なるように物体側へ移動している。このとき第３群と第
４群の間隔が広角端に比べて望遠端において増大するよ
うに移動させている。これにより独立系としてみたとき
の第３群と第４群の合成系が変倍に伴い増倍となるよう
にしている。At the time of zooming from the wide-angle end to the telephoto end, each of the first, second, and third units moves toward the object side with the second unit changing the relative positional relationship with the other lens units. The combined power of the front group moves so as to be weaker at the telephoto end than at the wide-angle end. In addition, the fourth and fifth units are moved toward the object side so that the distance between them is reduced. At this time, the lens is moved so that the distance between the third lens unit and the fourth lens unit is larger at the telephoto end than at the wide-angle end. Thereby, the combined system of the third group and the fourth group, when viewed as an independent system, is multiplied with magnification.

【００１５】本発明においては、広角端において前記第
１群と第２群の合成屈折力は負であり、正の屈折力の第
３群とから前群全体としてレトロフォーカスタイプとな
っている。これにより前群の前側主点が像面側に位置
し、前群と後群のレンズ面同志の干渉を防止しつつ、広
画角化を容易にしている。又第１群を負の屈折力、第２
群を負の屈折力として広角端での前群におけるレトロフ
ォーカスタイプとしての強い負の屈折力を第１群と第２
群に分担させて、広画角化を容易にしている。そして第
４群を物体側へ繰り出して無限遠物体から近距離物体へ
のフォーカスを行なっている。In the present invention, at the wide-angle end, the combined refractive power of the first and second units is negative, and the third unit having a positive refractive power and the entire front unit are of a retrofocus type. As a result, the front principal point of the front group is located on the image plane side, and widening the angle of view is facilitated while preventing interference between the lens surfaces of the front group and the rear group. Further, the first lens unit has a negative refractive power,
A strong negative refractive power as a retrofocus type in the front group at the wide-angle end as a negative refractive power of the first and second groups.
Allocated to the group to facilitate widening of the angle of view. Then, the fourth lens unit is moved toward the object side to focus from an object at infinity to an object at a short distance.

【００１６】本発明のズームレンズにおいては、レンズ
系全体の焦点距離ｆは次式で表わせられる。In the zoom lens of the present invention, the focal length f of the whole lens system is expressed by the following equation.

【００１７】 ｆ＝ｆＡ・β４・β５ （β４＞０，β５＞０） ・・・・・・（ａ） ここでｆＡは前記前群の合成焦点距離、βｉは第ｉ群の
横倍率を表わす。F = fA · β4 · β5 (β4> 0, β5> 0) (a) where fA represents the composite focal length of the front group, and βi represents the lateral magnification of the i-th group. .

【００１８】本発明では（ａ）式で理解できるように広
角端から望遠端への変倍の際は、横倍率β４，β５の値
を大きくすると同時に、前群の合成焦点距離ｆＡを長く
する（前群の合成屈折力を弱める）ことにより、より効
率の良い変倍作用を行なっている。又、正の屈折力の第
４群と負の屈折力の第５群との間隔を広角端に比べて望
遠端で狭く（減少）なるようにして、第５群に変倍効果
を与えて高変倍化を容易にしている。又後群は望遠端で
より発散性（負）の屈折力を強めるようにして、正の屈
折力の前群と共に望遠型（テレフォトタイプ）を構成
し、レンズ系全体の小型化を図っている。In the present invention, as can be understood from the equation (a), at the time of zooming from the wide-angle end to the telephoto end, the values of the lateral magnifications β4 and β5 are increased and, at the same time, the combined focal length fA of the front group is increased. By reducing the combined refracting power of the front group, a more efficient zooming effect is achieved. Also, the distance between the fourth lens unit having a positive refractive power and the fifth lens unit having a negative refractive power is made narrower (decreased) at the telephoto end than at the wide-angle end, thereby giving a zooming effect to the fifth lens unit. It facilitates high magnification. Also, the rear lens unit has a more divergent (negative) refractive power at the telephoto end, and forms a telephoto type (telephoto type) together with the front lens unit having a positive refractive power to reduce the size of the entire lens system. I have.

【００１９】特に本発明では図１に示すような近軸屈折
力配置を採ることにより、広角端の焦点距離が画面対角
線長より小さくなるような撮影画角の広画角化を図って
いる。In particular, in the present invention, by adopting a paraxial refractive power arrangement as shown in FIG. 1, the photographic field angle is widened so that the focal length at the wide angle end becomes smaller than the screen diagonal length.

【００２０】具体的には、前群は負の屈折力の第１群、
負の屈折力の第２群そして正の屈折力の第３群より成
り、広角端から望遠端への変倍に際して、第１群と第２
群の間隔が増大、第２群と第３群の間隔が減少するよう
に各レンズ群が物体側へ移動している。これにより前群
による変倍効果を高めている。Specifically, the front group is a first group having a negative refractive power,
The second lens unit includes a second lens unit having a negative refractive power and a third lens unit having a positive refractive power. The first lens unit and the second lens unit perform zooming from the wide-angle end to the telephoto end.
Each lens group moves toward the object side such that the distance between the groups increases and the distance between the second and third groups decreases. This enhances the zooming effect of the previous group.

【００２１】尚、本発明では機構の簡素化のために第１
群と第３群を一体的に移動させているが、独立に移動さ
せても良い。これによれば設計の自由度を増加させるこ
とができる。In the present invention, the first mechanism is used to simplify the mechanism.
Although the group and the third group are moved integrally, they may be moved independently. According to this, the degree of freedom of design can be increased.

【００２２】本発明においては以上のようなレンズ構成
において、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、第ｉ群の広角端における横倍率を
βｉＷ、広角端と望遠端における前群の合成屈折力をφ
123T、ズーム比をＺとしたとき、 ０．５＜｜ｆ５／ｆＷ｜＜１．５ ・・・（１） １．１＜β５Ｗ＜１．８ ・・・（２） １．０＜｜ｆ１／ｆＷ｜＜６．０ ・・・（５） １．０＜｜ｆ２／ｆＷ｜＜６．０ ・・・（６） ０．２５＜（φ１２３Ｗ／φ１２３Ｔ）／Ｚ＜０．８ ・・・（７） ０．２５＜β４Ｗ＜０．５５ ・・・（８） ０．１＜ｆ５・（１−β５Ｗ）／ｆＷ＜０．７ ・・・（９） なる条件を満足するようにしている。これによりさらに
レンズ系全体の小型化を図りつつ、全変倍範囲にわたり
高い光学性能を得ている。In the present invention, in the above lens configuration, the focal length of the i-th lens unit is fi, the focal length of the whole system at the wide-angle end is fW, the lateral magnification at the wide-angle end of the i-th unit is βiW, The combined refractive power of the front group at the telephoto end is φ
Assuming 123T and the zoom ratio as Z, 0.5 <| f5 / fW | <1.5 (1) 1.1 <β5W <1.8 (2) 1.0 <| f1 /FW|<6.0 (5) 1.0 <| f2 / fW | <6.0 (6) 0.25 <(φ123W / φ123T) / Z <0.8 (7) 0.25 <β4W <0.55 (8) 0.1 <f5 · (1−β5W) / fW <0.7 (9) . This achieves high optical performance over the entire zoom range while further miniaturizing the entire lens system.

【００２３】次に前述の各条件式の技術的意味について
説明する。Next, the technical meaning of each of the above conditional expressions will be described.

【００２４】条件式（１）は第５群の負の屈折力に関
し、主に変倍を効果的に行なうためのものである。条件
式（１）の上限値を越えて第５群の負の屈折力が弱くな
ってくると、変倍時に該レンズ群による変倍効果が弱く
なるため、結果として一定の変倍比を得るためには各レ
ンズ群の移動量を大きくせねばならずレンズ全長が増加
してしまう。The conditional expression (1) is mainly for effectively performing zooming with respect to the negative refractive power of the fifth lens unit. If the negative refractive power of the fifth lens unit becomes weaker beyond the upper limit of conditional expression (1), the zooming effect of the lens unit becomes weaker during zooming, so that a constant zoom ratio is obtained. For this purpose, the amount of movement of each lens group must be increased, and the overall length of the lens increases.

【００２５】又、条件式（１）の下限値を越えること
は、広角端において、レンズ系は前記第１〜第４群の合
成屈折力は正、第５群の屈折力は負であるためテレフォ
トタイプとしての作用が強くなりすぎることになる。If the lower limit of conditional expression (1) is exceeded, it means that at the wide-angle end, the combined refractive power of the first to fourth units is positive and the refractive power of the fifth unit is negative at the wide-angle end. The effect as a telephoto type will be too strong.

【００２６】その為結果として、レンズ系のバックフォ
ーカスが短くなりすぎ、一定の周辺光量を確保するため
に第５群のレンズ外径の大型化をまねくと同時に、該レ
ンズ群の屈折力が強くなりすぎるため高次の像面湾曲や
非点収差が発生し、これを補正することが困難となって
くる。As a result, the back focus of the lens system becomes too short, which leads to an increase in the outer diameter of the fifth lens group in order to secure a constant peripheral light amount, and at the same time, the refractive power of the lens group becomes strong. Too much distortion causes higher-order field curvature and astigmatism, which makes it difficult to correct them.

【００２７】条件式（２）は第５群の広角端における横
倍率に関する。Conditional expression (2) relates to the lateral magnification of the fifth lens unit at the wide-angle end.

【００２８】今、広角端におけるレンズ系のバックフォ
ーカスをＢｆＷとすると、 ＢｆＷ＝ｆ５・（１−β５Ｗ） と表わせられる。Assuming that the back focus of the lens system at the wide angle end is BfW, BfW = f5 · (1−β5W).

【００２９】そこで本発明では条件式（１）と共に条件
式（２）の値を適切に設定することによりレンズ系の全
長と諸収差をバランス良く補正している。Therefore, in the present invention, the total length of the lens system and various aberrations are corrected in a well-balanced manner by appropriately setting the value of the conditional expression (2) together with the conditional expression (1).

【００３０】条件式（２）の上限値を越えて結像倍率が
大きくなるとバックフォーカスは長くなるが第１〜第４
群の屈折力が強くなりすぎ、収差変動が大きくなってく
る。他方下限値を越えて結像倍率が小さくなると所定の
バックフォーカスを得るのが困難となり、又第５群のレ
ンズ外径が増大してくるので良くない。条件式（５）は
広角端における全系と第１群の屈折力の比に関するもの
であり、条件式（５）の上限値を越えると第１群の屈折
力が弱くなりすぎてレンズ全長が大きくなってしまう。
又下限値を越えると第１群の屈折力が強くなるため広角
端において所定のバックフォーカスを確保するのが困難
になってしまう。条件式（６）は広角端における全系と
第２群の屈折力の比に関するものであり、条件式（６）
の上限値を越えると第２群の屈折力が弱くなるため、変
倍の際のレンズ群の移動量が大きくなりレンズ系の増大
をまねく。又下限値を越えると第２群の屈折力が強くな
りすぎ、それに伴い第３群の屈折力も強くなってしまい
球面収差の補正が難しくなってくるので良くない。条件
式（７）は前群の変倍比に関するものである。条件式
（７）の上限値を越えると前群での変倍分担が大きくな
りすぎ、前群におけるレンズ群の屈折力が強くなった
り、変倍の際の各レンズ群の移動量が増大してくる。又
下限値を越えると後群での変倍分担が大きくなりすぎ、
所定の変倍比を確保するための後群の各レンズ群の移動
量が増大してくるので良くない。条件式（８）は広角端
における第４群の横倍率に関するものである。条件式
（８）の上限値を越えると、広角端においてバックフォ
ーカスが取りずらくなり、結果として第５群のレンズ外
径の増大をまねいてしまう。又、下限値を越えると、一
定の焦点距離を得るために、他のレンズ群の屈折力が強
くなってくるため変倍時の収差変動を補正することが難
しくなってくる。更に前群の焦点距離をより長くしなけ
ればならず、レンズ全長が長くなってくるので良くな
い。条件式（９）は第５群の屈折力と横倍率を適切に設
定し、主に所定のバックフォーカスを得るためのもので
ある。条件式（９）の上限値を越えると広角端でバック
フォーカスが必要以上に長くなり、レンズ全長が増大し
てくる。又下限値を越えると逆に広角端で所定のバック
フォーカスを得るのが難しくなると共に第５群のレンズ
外径が増大してくるので良くない。When the imaging magnification is increased beyond the upper limit value of the conditional expression (2), the back focus becomes longer, but the first to fourth focal lengths are increased.
The refracting power of the group becomes too strong, and the aberration variation increases. On the other hand, if the imaging magnification becomes smaller than the lower limit, it becomes difficult to obtain a predetermined back focus, and the outer diameter of the lens of the fifth group increases, which is not good. The conditional expression (5) relates to the ratio of the refractive power of the first lens unit to the total system at the wide-angle end. If the upper limit of conditional expression (5) is exceeded, the refractive power of the first lens unit becomes too weak, and the total lens length is reduced. It gets bigger.
If the lower limit value is exceeded, the refractive power of the first lens unit becomes strong, so that it becomes difficult to secure a predetermined back focus at the wide-angle end. Conditional expression (6) relates to the ratio of the refractive power of the entire system at the wide-angle end to the refractive power of the second unit, and conditional expression (6)
When the value exceeds the upper limit, the refracting power of the second unit becomes weak, so that the amount of movement of the lens unit at the time of zooming becomes large, which leads to an increase in the lens system. If the lower limit value is exceeded, the refractive power of the second lens unit becomes too strong, and the refractive power of the third lens unit becomes too strong, making it difficult to correct spherical aberration. Conditional expression (7) relates to the zoom ratio of the front group. If the upper limit of conditional expression (7) is exceeded, the magnification change in the front group becomes too large, the refractive power of the lens group in the front group becomes strong, and the movement amount of each lens group during zooming increases. Come. In addition, if the lower limit is exceeded, the variable power share in the rear group becomes too large,
It is not good because the amount of movement of each lens unit in the rear group for securing a predetermined zoom ratio increases. Conditional expression (8) relates to the lateral magnification of the fourth lens unit at the wide-angle end. When the value exceeds the upper limit of conditional expression (8), it becomes difficult to obtain a back focus at the wide-angle end, which results in an increase in the outer diameter of the fifth lens unit. If the lower limit value is exceeded, the refractive power of the other lens units will increase in order to obtain a constant focal length, making it difficult to correct aberration fluctuations during zooming. Further, the focal length of the front group must be made longer, which is not good because the overall length of the lens becomes longer. Conditional expression (9) is for appropriately setting the refractive power and the lateral magnification of the fifth lens unit and mainly for obtaining a predetermined back focus. When the value exceeds the upper limit of conditional expression (9), the back focus becomes unnecessarily long at the wide-angle end, and the overall length of the lens increases. On the other hand, if the lower limit is exceeded, it becomes difficult to obtain a predetermined back focus at the wide-angle end, and the outer diameter of the lens of the fifth group increases, which is not good.

【００３１】尚、本発明において変倍に伴う収差変動を
少なくしつつ広画角化を図り、画面全体にわたり高い光
学性能を確保するには各レンズ群を次の如く構成するの
が良い。In the present invention, in order to widen the angle of view while minimizing aberration fluctuations due to zooming, and to ensure high optical performance over the entire screen, it is preferable to configure each lens unit as follows.

【００３２】（１）広角端における前記前群の合成屈折
力をφ123Wとするとき、 ０．３＜ｆＷ・φ123W＜０．９ ・・・・・・（３） ０．６＜ｆ３／ｆＷ＜２．０ ・・・・・・・・・・（４） なる条件を満足することが良い。(1) When the combined refractive power of the front unit at the wide-angle end is φ123W , 0.3 <fW · φ123W <0.9 (3) 0.6 <f3 / fW <2.0 It is preferable that the following condition is satisfied.

【００３３】条件式（３）は前群の屈折力に関し、条件
式（３）の上限値を越えると、広角端において該前群の
屈折力が強くなりすぎテレフォト系の作用が強くなるた
め正のバックフォーカスを得ることが困難になる。又、
下限値を越えると前群の屈折力が弱まり、レンズ全長が
増大すると同時に、該後群のレンズ群の正の屈折力を強
めて広角端の焦点距離を維持せねばならないため、変倍
全域にわたって諸収差のバランスをとることが困難とな
る。Conditional expression (3) relates to the refractive power of the front lens group. If the upper limit of conditional expression (3) is exceeded, the refractive power of the front lens group becomes too strong at the wide-angle end, and the effect of the telephoto system becomes strong. It is difficult to obtain the back focus. or,
Exceeding the lower limit lowers the refractive power of the front group and increases the overall length of the lens.At the same time, the positive refractive power of the rear group must be increased to maintain the focal length at the wide-angle end. It becomes difficult to balance various aberrations.

【００３４】条件式（４）は第３群の正の屈折力に関す
るものであり、条件式（４）の上限値を越えると、第３
群の屈折力が弱くなるため、変倍の際のレンズ群の移動
量が大きくなりレンズ系の増大をまねく。又、下限値を
越えると、第３群で高次の球面収差が強く発生するた
め、これを補正することが困難となってくる。Conditional expression (4) relates to the positive refractive power of the third lens unit.
Since the refracting power of the group is weak, the amount of movement of the lens group at the time of zooming is large, which leads to an increase in the lens system. If the lower limit is exceeded, high-order spherical aberration is strongly generated in the third lens unit, and it becomes difficult to correct this.

【００３５】尚、本発明において、特に広角端でのレン
ズ全長の短縮化を図りつつ、光学性能を良好に補正する
には前述の条件式（３），（４）の上限値と下限値を次
の如く ０．３５＜ｆＷ・φ123W＜０．８０ ・・・・・・（３ａ） ０．７５＜ｆ３／ｆＷ＜１．８ ・・・・・・・・・・・・（４ａ） 設定するのが良い。In the present invention, the upper and lower limits of the above-mentioned conditional expressions (3) and (4) must be satisfied in order to correct the optical performance satisfactorily while reducing the total length of the lens particularly at the wide-angle end. 0.35 <fW · φ 123W <0.80 (3a) 0.75 <f3 / fW <1.8 (4a) Good to set.

【００３６】[0036]

【００３７】[0037]

【００３８】[0038]

【００３９】[0039]

【００４０】[0040]

【００４１】[0041]

【００４２】（２）正の屈折力の第４群は少なくとも１
枚ずつの正レンズと負レンズとを有し、このうち最も物
体側のレンズ面は物体側に凹面を向け、最も像面側のレ
ンズ面は像面側に凸面を向けたレンズ構成とするのが良
い。(2) The fourth group having a positive refractive power has at least 1
Each lens has a positive lens and a negative lens, of which the lens surface closest to the object side has a concave surface facing the object side, and the lens surface closest to the image surface has a convex surface facing the image surface side. Is good.

【００４３】（３）本発明のズームレンズに非球面を導
入するときは、最も像面側のレンズ面に非球面を導入す
れば、望遠端での像面弯曲と球面収差及び変倍に伴う収
差変動及び画面全体の収差補正を容易に補正するのがで
きる。又第５群に導入すれば、主に軸外収差を良好に補
正することができる。(3) When an aspherical surface is introduced into the zoom lens of the present invention, if an aspherical surface is introduced into the lens surface closest to the image plane, the curvature of field at the telephoto end, spherical aberration, and zooming will occur. It is possible to easily correct aberration fluctuation and aberration correction of the entire screen. In addition, if it is introduced into the fifth lens group, mainly off-axis aberration can be favorably corrected.

【００４４】（４）負の屈折力の第５群は少なくとも１
枚ずつの物体側に凹面を向けた負レンズと正レンズとを
有し、第５群中の正レンズと負レンズの材質のアッベ数
の平均値を各々ν５Ｐ，ν５Ｎとしたとき、 １２＜ν５Ｎ−ν５Ｐ＜３５ ・・・・・・（１０） なる条件を満足するのが良い。条件式（１０）の上限値
又は下限値を外れると変倍時における色収差変動が多く
発生してきて、これを他のレンズ群にて補正することが
困難となってくる。(4) The fifth group having a negative refractive power has at least 1
When there are a negative lens and a positive lens each having a concave surface facing the object side for each sheet, and the average values of Abbe numbers of the materials of the positive lens and the negative lens in the fifth group are ν5P and ν5N, respectively, 12 <ν5N −ν5P <35 (10) It is preferable to satisfy the following condition. If the upper limit or the lower limit of conditional expression (10) is not satisfied, chromatic aberration fluctuations during zooming often occur, and it becomes difficult to correct this with another lens group.

【００４５】（５）絞りは第３群の最も像面側のレンズ
面から第４群の最も像面側のレンズ面の間に存在する空
気間隔中に配置するのが入射瞳を適切な位置に配置する
ことができ、変倍による収差変動を抑えることができる
ので好ましい。そして絞りを変倍時に他のレンズ群とは
独立に移動させても良く、又、他のレンズ群と一体に移
動させても良い。それにより変倍時に移動する入射瞳位
置近傍に絞り位置を配置することが可能となり、小絞り
時の像面湾曲収差変化を防止するのに有利となる。(5) The stop should be located at an appropriate distance from the lens surface closest to the image plane of the third lens unit to the lens surface closest to the image surface of the fourth lens unit so that the entrance pupil is located at an appropriate position. Are preferable because aberration fluctuation due to zooming can be suppressed. The stop may be moved independently of the other lens groups when zooming, or may be moved integrally with the other lens groups. This makes it possible to arrange the stop position near the entrance pupil position that moves during zooming, which is advantageous for preventing a change in field curvature aberration at the time of a small stop.

【００４６】又、第４群でフォーカスを行なう場合、第
４群が絞りを含む場合、絞りを光軸上を固定状態にして
フォーカス群を移動させることはフォーカス時に絞り機
構を移動させるための駆動トルクの低減を行うことがで
きるので好ましい。When focusing is performed by the fourth lens unit, and when the fourth lens unit includes an aperture, moving the focus unit with the aperture fixed on the optical axis is a driving operation for moving the aperture mechanism during focusing. This is preferable because torque can be reduced.

【００４７】（６）第４群を２つ以上のレンズ群に分割
し、変倍中又はフォーカスの際に各レンズ群の間隔を変
化させれば、変倍及びフォーカスの際の収差変動を少な
くすることができるので好ましい。(6) If the fourth unit is divided into two or more lens units and the distance between the lens units is changed during zooming or during focusing, aberration variation during zooming and focusing is reduced. Is preferred.

【００４８】（７）本発明におけるフォーカスは第４群
を物体側へ移動させることにより、無限遠物体から近距
離物体へのフォーカスを行なっているが、他のレンズ群
を移動することによっても良い。例えば該前群を物体側
へ移動する方式でも良い。(7) In the present invention, the focus is moved from the object at infinity to the object at a short distance by moving the fourth unit to the object side, but it may be moved by moving another lens unit. . For example, a method of moving the front group to the object side may be used.

【００４９】又、広角端においてバックフォーカスが充
分にある場合は第５群を像面側に移動して行なっても良
く、この際は第１群のレンズ外径の小型化を行なうのに
有効となる。又、第１群から第５群中の２つ以上のレン
ズ群を同時に移動させて行なっても良い。When the back focus is sufficient at the wide-angle end, the fifth unit may be moved to the image plane side, and in this case, it is effective to reduce the outer diameter of the lens of the first unit. Becomes Alternatively, two or more lens groups in the first to fifth groups may be simultaneously moved.

【００５０】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.

【００５１】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。Table 1 shows the relationship between the above-mentioned conditional expressions and various numerical values in the numerical examples.

【００５２】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 aspheric surface has an X-axis in the optical axis direction, an H-axis in a direction perpendicular to the optical axis, a positive traveling direction of light, R is a paraxial radius of curvature,
When A, B, C, D, and E are aspheric coefficients, respectively,

【００５３】[0053]

【数１】 なる式で表わしている。(Equation 1) It is represented by the following equation.

【００５４】 （数値実施例１） F= 28.84〜89.41 fNO= 1:3.8〜8.2 2ω= 73.8°〜27.2° R 1= -217.48 D 1= 2.00 N 1=1.80518 ν 1= 25.4 R 2= -103.00 D 2= 1.20 N 2=1.69680 ν 2= 55.5 R 3= 48.69 D 3=可変 R 4= 154.19 D 4= 1.30 N 3=1.65844 ν 3= 50.9 R 5= 37.47 D 5=可変 R 6= 29.87 D 6= 1.00 N 4=1.84666 ν 4= 23.8 R 7= 23.19 D 7= 2.90 N 5=1.48749 ν 5= 70.2 R 8= -101.43 D 8= 0.30 R 9= 33.35 D 9= 2.30 N 6=1.60311 ν 6= 60.7 R10= -173.29 D10=可変 R11= -17.33 D11= 0.87 N 7=1.64769 ν 7= 33.8 R12= -64.01 D12= 1.00 R13=∞ (絞り) D13= 1.00 R14=-1012.52 D14= 0.70 N 8=1.48749 ν 8= 70.2 R15= 39.15 D15= 1.80 N 9=1.84666 ν 9= 23.8 R16= -37.96 D16= 5.17 R17= 40.91 D17= 1.10 N10=1.84666 ν10= 23.8 R18= 11.63 D18= 5.60 N11=1.58313 ν11= 59.4 R19= -23.69 D19=可変 R20= -29.78 D20= 3.60 N12=1.84666 ν12= 23.8 R21= -18.07 D21= 0.20 R22= -22.10 D22= 1.30 N13=1.74320 ν13= 49.3 R23= 634.28 D23= 4.38 R24= -22.75 D24= 1.50 N14=1.72916 ν14= 54.7 R25= -113.54 非球面係数 R19 K= -1.96×10-1 A= 0 B= 1.09×10-5 C= 8.05×10-8 D= -2.53×10-9 E= 0 (Numerical Example 1) F = 28.84 to 89.41 fNO = 1: 3.8 to 8.2 2ω = 73.8 ° to 27.2 ° R 1 = -217.48 D 1 = 2.00 N 1 = 1.80518 ν 1 = 25.4 R 2 = -103.00 D 2 = 1.20 N 2 = 1.69680 ν 2 = 55.5 R 3 = 48.69 D 3 = Variable R 4 = 154.19 D 4 = 1.30 N 3 = 1.65844 ν 3 = 50.9 R 5 = 37.47 D 5 = Variable R 6 = 29.87 D 6 = 1.00 N 4 = 1.84666 ν 4 = 23.8 R 7 = 23.19 D 7 = 2.90 N 5 = 1.48749 ν 5 = 70.2 R 8 = -101.43 D 8 = 0.30 R 9 = 33.35 D 9 = 2.30 N 6 = 1.60311 ν 6 = 60.7 R10 = -173.29 D10 = variable R11 = -17.33 D11 = 0.87 N 7 = 1.64769 ν 7 = 33.8 R12 = -64.01 D12 = 1.00 R13 = ∞ (aperture) D13 = 1.00 R14 = -1012.52 D14 = 0.70 N 8 = 1.48749 ν 8 = 70.2 R15 = 39.15 D15 = 1.80 N 9 = 1.84666 ν 9 = 23.8 R16 = -37.96 D16 = 5.17 R17 = 40.91 D17 = 1.10 N10 = 1.84666 ν10 = 23.8 R18 = 11.63 D18 = 5.60 N11 = 1.58313 ν11 = 59.4 R19 = -23.69 D19 = variable R20 = -29.78 D20 = 3.60 N12 = 1.84666 ν12 = 23.8 R21 = -18.07 D21 = 0.20 R22 = -22.10 D22 = 1.30 N13 = 1.74320 ν13 = 49.3 R23 = 634.28 D23 = 4.38 R24 = -22.75 D24 = 1.50 N14 = 1.72916 ν14 = 54.7 R25 = -113.54 Aspheric coefficient R19 K = -1.96 × 10 -1 A = 0 B = 1.09 × 10 -5 C = 8.05 × 10 -8 D = -2.53 × 10 -9 E = 0

【００５５】[0055]

【表１】 （数値実施例２） F= 30.43〜100.00 fNO= 1:3.7〜8.2 2ω= 70.8°〜24.4° R 1= -677.46 D 1= 2.00 N 1=1.80518 ν 1= 25.4 R 2= -69.17 D 2= 1.20 N 2=1.69680 ν 2= 55.5 R 3= 63.43 D 3=可変 R 4= 3704.92 D 4= 1.30 N 3=1.65844 ν 3= 50.9 R 5= 45.60 D 5=可変 R 6= 32.60 D 6= 1.00 N 4=1.84666 ν 4= 23.8 R 7= 22.08 D 7= 3.20 N 5=1.48749 ν 5= 70.2 R 8= -224.31 D 8= 0.30 R 9= 36.51 D 9= 2.70 N 6=1.60311 ν 6= 60.7 R10= -122.67 D10=可変 R11=∞ (絞り) D11=可変 R12= -17.93 D12= 0.87 N 7=1.64769 ν 7= 33.8 R13= -71.56 D13= 2.00 R14= -228.00 D14= 0.70 N 8=1.48749 ν 8= 70.2 R15= 44.17 D15= 1.80 N 9=1.84666 ν 9= 23.8 R16= -46.21 D16= 5.17 R17= 39.16 D17= 1.10 N10=1.84666 ν10= 23.8 R18= 13.54 D18= 5.60 N11=1.58313 ν11= 59.4 R19= -22.09 D19=可変 R20= -36.36 D20= 3.60 N12=1.84666 ν12= 23.8 R21= -18.73 D21= 0.20 R22= -22.97 D22= 1.30 N13=1.78590 ν13= 44.2 R23= -161.56 D23= 4.50 R24= -18.57 D24= 1.50 N14=1.72916 ν14= 54.7 R25= -232.78 非球面係数 R19 K= -3.97×10-1 A= 0 B= 1.18×10-5 C= 7.44×10-8 D= -1.47×10-9 E= 0 [Table 1] (Numerical Example 2) F = 30.43 to 100.00 fNO = 1: 3.7 to 8.2 2ω = 70.8 ° to 24.4 ° R 1 = -677.46 D 1 = 2.00 N 1 = 1.80518 ν 1 = 25.4 R 2 = -69.17 D 2 = 1.20 N 2 = 1.69680 ν 2 = 55.5 R 3 = 63.43 D 3 = Variable R 4 = 3704.92 D 4 = 1.30 N 3 = 1.65844 ν 3 = 50.9 R 5 = 45.60 D 5 = Variable R 6 = 32.60 D 6 = 1.00 N 4 = 1.84666 ν 4 = 23.8 R 7 = 22.08 D 7 = 3.20 N 5 = 1.48749 ν 5 = 70.2 R 8 = -224.31 D 8 = 0.30 R 9 = 36.51 D 9 = 2.70 N 6 = 1.60311 ν 6 = 60.7 R10 = -122.67 D10 = variable R11 = ∞ (aperture) D11 = variable R12 = -17.93 D12 = 0.87 N 7 = 1.64769 ν 7 = 33.8 R13 = -71.56 D13 = 2.00 R14 = -228.00 D14 = 0.70 N 8 = 1.48749 ν 8 = 70.2 R15 = 44.17 D15 = 1.80 N 9 = 1.84666 ν 9 = 23.8 R16 = -46.21 D16 = 5.17 R17 = 39.16 D17 = 1.10 N10 = 1.84666 ν10 = 23.8 R18 = 13.54 D18 = 5.60 N11 = 1.58313 ν11 = 59.4 R19 = -22.09 D19 = variable R20 = -36.36 D20 = 3.60 N12 = 1.84666 ν12 = 23.8 R21 = -18.73 D21 = 0.20 R22 = -22.97 D22 = 1.30 N13 = 1.78590 ν13 = 44.2 R23 = -161.56 D23 = 4.50 R24 = -18.57 D24 = 1.50 N14 = 1.72916 ν14 = 54.7 R25 = -232.78 Aspherical coefficient R19 K = -3.97 × 10 -1 A = 0 B = 1.18 × 10 -5 C = 7.44 × 10 -8 D = -1.47 × 10 -9 E = 0

【００５６】[0056]

【表２】 （数値実施例３） F= 30.00〜100.00 fNO= 1:3.6〜8.2 2ω= 71.6°〜24.4° R 1= -228.47 D 1= 2.00 N 1=1.80518 ν 1= 25.4 R 2= -61.62 D 2= 1.20 N 2=1.69680 ν 2= 55.5 R 3= 60.27 D 3=可変 R 4= 300.46 D 4= 1.30 N 3=1.65844 ν 3= 50.9 R 5= 47.91 D 5=可変 R 6= 32.90 D 6= 1.00 N 4=1.84666 ν 4= 23.8 R 7= 22.76 D 7= 3.20 N 5=1.48749 ν 5= 70.2 R 8= -264.26 D 8= 0.30 R 9= 34.66 D 9= 2.50 N 6=1.60311 ν 6= 60.7 R10= -148.49 D10=可変 R11=∞ (絞り) D11= 1.70 R12= -18.05 D12= 0.87 N 7=1.64769 ν 7= 33.8 R13= -63.03 D13= 2.00 R14= -167.30 D14= 0.70 N 8=1.48749 ν 8= 70.2 R15= 46.92 D15= 1.80 N 9=1.84666 ν 9= 23.8 R16= -49.81 D16= 5.17 R17= 36.08 D17= 1.10 N10=1.84666 ν10= 23.8 R18= 14.30 D18= 5.60 N11=1.58313 ν11= 59.4 R19= -24.31 D19=可変 R20= -19.49 D20= 3.60 N12=1.84666 ν12= 23.8 R21= -16.47 D21= 4.50 R22= -16.05 D22= 1.50 N13=1.77250 ν13= 49.6 R23= 185.92 非球面係数 R19 K= -6.76×10-1 A= 0 B= 1.7138×10-8 C= 7.38×10-8 D= -1.15×10-9 E= 0 非球面係数 R22 K= 0 A= 0 B= 1.69×10-5 C= 3.53×10-8 D= -1.80×10-8 E= 0 [Table 2] (Numerical Example 3) F = 30.0 to 100.00 fNO = 1: 3.6 to 8.2 2ω = 71.6 ° to 24.4 ° R 1 = -228.47 D 1 = 2.00 N 1 = 1.80518 ν 1 = 25.4 R 2 = -61.62 D 2 = 1.20 N 2 = 1.69680 ν 2 = 55.5 R 3 = 60.27 D 3 = Variable R 4 = 300.46 D 4 = 1.30 N 3 = 1.65844 ν 3 = 50.9 R 5 = 47.91 D 5 = Variable R 6 = 32.90 D 6 = 1.00 N 4 = 1.84666 ν 4 = 23.8 R 7 = 22.76 D 7 = 3.20 N 5 = 1.48749 ν 5 = 70.2 R 8 = -264.26 D 8 = 0.30 R 9 = 34.66 D 9 = 2.50 N 6 = 1.60311 ν 6 = 60.7 R10 = -148.49 D10 = variable R11 = ∞ (aperture) D11 = 1.70 R12 = -18.05 D12 = 0.87 N 7 = 1.64769 ν 7 = 33.8 R13 = -63.03 D13 = 2.00 R14 = -167.30 D14 = 0.70 N 8 = 1.48749 ν 8 = 70.2 R15 = 46.92 D15 = 1.80 N 9 = 1.84666 ν 9 = 23.8 R16 = -49.81 D16 = 5.17 R17 = 36.08 D17 = 1.10 N10 = 1.84666 ν10 = 23.8 R18 = 14.30 D18 = 5.60 N11 = 1.58313 ν11 = 59.4 R19 = -24.31 D19 = variable R20 = -19.49 D20 = 3.60 N12 = 1.84666 ν12 = 23.8 R21 = -16.47 D21 = 4.50 R22 = -16.05 D22 = 1.50 N13 = 1.77250 ν13 = 49.6 R23 = 185.92 aspheric coefficients R19 K = -6.76 × 10 - 1 A = 0 B = 1.7138 × 10 -8 C = 7.38 × 10 -8 D = -1.15 × 10 -9 E = 0 Aspheric coefficient R22 K = 0 A = 0 B = 1.69 × 10 -5 C = 3.53 × 10 -8 D = -1.80 × 10 -8 E = 0

【００５７】[0057]

【表３】 [Table 3]

【００５８】[0058]

【発明の効果】本発明によれば以上のように、全体とし
て５つのレンズ群より構成し、変倍における各レンズ群
の移動条件や屈折力等を適切に設定することにより、広
角端の撮影画角が７４度程度、変倍比３．５程度の全変
倍範囲にわたり高い光学性能を有したズームレンズを達
成することができる。As described above, according to the present invention, the wide-angle end photographing is performed by appropriately configuring the moving conditions and the refracting power of each lens unit during zooming by forming the lens system from five lens units as a whole. A zoom lens having high optical performance over the entire zoom range with an angle of view of about 74 degrees and a zoom ratio of about 3.5 can be achieved.

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

【図１】 本発明のズームレンズの近軸屈折力配置の説
明図FIG. 1 is an explanatory diagram of a paraxial refractive power arrangement of a zoom lens according to the present invention.

【図２】 本発明の数値実施例１の広角端のレンズ断面
図FIG. 2 is a sectional view of a lens at a wide-angle end according to Numerical Embodiment 1 of the present invention.

【図３】 本発明の数値実施例２の広角端のレンズ断面
図FIG. 3 is a sectional view of a lens at a wide-angle end according to a second numerical embodiment of the present invention.

【図４】 本発明の数値実施例３の広角端のレンズ断面
図FIG. 4 is a sectional view of a lens at a wide-angle end according to a third numerical embodiment of the present invention.

【図５】 本発明の数値実施例１の広角端の収差図FIG. 5 is an aberration diagram at a wide-angle end according to Numerical Embodiment 1 of the present invention.

【図６】 本発明の数値実施例１の中間の収差図FIG. 6 is an intermediate aberration diagram of the numerical example 1 of the present invention.

【図７】 本発明の数値実施例１の望遠端の収差図FIG. 7 is an aberration diagram at a telephoto end in Numerical Example 1 of the present invention.

【図８】 本発明の数値実施例２の広角端の収差図FIG. 8 is an aberration diagram at a wide angle end according to Numerical Example 2 of the present invention.

【図９】 本発明の数値実施例２の中間の収差図FIG. 9 is an intermediate aberration diagram of the numerical example 2 of the present invention.

【図１０】 本発明の数値実施例２の望遠端の収差図FIG. 10 is an aberration diagram at a telephoto end in Numerical Example 2 of the present invention.

【図１１】 本発明の数値実施例３の広角端の収差図FIG. 11 is an aberration diagram at a wide angle end according to Numerical Example 3 of the present invention.

【図１２】 本発明の数値実施例３の中間の収差図FIG. 12 is an intermediate aberration diagram of the numerical example 3 of the present invention.

【図１３】 本発明の数値実施例３の望遠端の収差図FIG. 13 is an aberration diagram at a telephoto end in Numerical Example 3 of the present invention.

【符号の説明】[Explanation of symbols]

Ｌ１ 第１群 Ｌ２ 第２群 Ｌ３ 第３群 Ｌ４ 第４群 Ｌ５ 第５群 ＳＰ 絞り ＩＰ 像面 ｄ ｄ線 ｇ ｇ線 Ｓ．Ｃ 正弦条件 ΔＳ サジタル像面 ΔＭ メリディオナル像面 L1 First group L2 Second group L3 Third group L4 Fourth group L5 Fifth group SP Aperture IP Image plane dd line gg line S. C Sine condition ΔS Sagittal image plane ΔM Meridional image plane

───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G02B 9/00 - 17/08 G02B 21/02 - 21/04 G02B 25/00 - 25/04 ──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. 7 , DB name) G02B 9/00-17/08 G02B 21/02-21/04 G02B 25/00-25/04

Claims (4)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 物体側より順に負の屈折力の第１群、負
の屈折力の第２群、正の屈折力の第３群の３つのレンズ
群より成り、広角端での合成屈折力が正の屈折力の前群
そして正の屈折力の第４群と負の屈折力の第５群の２つ
のレンズ群より成る後群とを有し、広角端から望遠端へ
の変倍に際して、該第１，第２，第３群は前群の合成屈
折力が広角端に比べて望遠端で弱まるように移動し、該
第４，第５群はそれらの間隔が狭くなるように移動して
おり、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、第ｉ群の広角端における横倍率を
βｉＷ、広角端と望遠端における前記前群の合成屈折力
をφ 123W ，φ 123T 、ズーム比をＺとしたとき、 ０．５＜｜ｆ５／ｆＷ｜＜１．５ １．１＜β５Ｗ＜１．８ １．０＜｜ｆ１／ｆＷ｜＜６．０ １．０＜｜ｆ２／ｆＷ｜＜６．０ ０．２５＜（φ１２３Ｗ／φ１２３Ｔ）／Ｚ＜０．８ ０．２５＜β４Ｗ＜０．５５ ０．１＜ｆ５・（１−β５Ｗ）／ｆＷ＜０．７ なる条件を満足すること を特徴とするズームレンズ。1. A first lens unit having a negative refractive power, a second lens unit having a negative refractive power, and a third lens unit having a positive refractive power. Has a front lens unit having a positive refractive power, a rear lens unit including a fourth lens unit having a positive refractive power, and a fifth lens unit having a negative refractive power, and when zooming from the wide-angle end to the telephoto end. The first, second, and third units move so that the combined refractive power of the front unit becomes weaker at the telephoto end than at the wide-angle end, and the fourth and fifth units move so that the distance between them decreases. do it
And the focal length of the i-th lens unit is fi
The focal length of the system is fW, and the lateral magnification at the wide-angle end of the i-th lens unit is
βiW, combined refractive power of the front group at wide-angle end and telephoto end
When φ is 123 W , φ 123T and the zoom ratio is Z, 0.5 <| f5 / fW | <1.5 1.1 <β5W <1.8 1.0 <| f1 / fW | <6.0 1.0 <| f2 / fW | <6.0 0.25 <(φ123W / φ123T) / Z <0.8 0.25 <β4W <0.55 0.1 <f5 · (1-β5W) / fW A zoom lens that satisfies the condition of <0.7 . 【請求項２】 広角端から望遠端への変倍に際して、第
１群と第２群の間隔が増大、第２群と第３群の間隔が減
少するように各レンズ群が物体側へ移動していることを
特徴とする請求項１のズームレンズ。2. In zooming from the wide-angle end to the telephoto end, each lens unit moves toward the object side so that the distance between the first and second units increases and the distance between the second and third units decreases. The zoom lens according to claim 1, wherein 【請求項３】 広角端における前記前群の合成屈折力を
φ123Wとするとき ０．３＜ｆＷ・φ123W＜０．９ ０．６＜ｆ３／ｆＷ＜２．０ なる条件を満足することを特徴とする請求項２のズーム
レンズ。3. When the combined refractive power of the front unit at the wide-angle end is φ 123 W , the following condition is satisfied: 0.3 <fW · φ 123W <0.9 0.6 <f3 / fW <2.0 The zoom lens according to claim 2, wherein: 【請求項４】 前記第５群は少なくとも１枚ずつの物体
側に凹面を向けた負レンズと正レンズとを有し、第５群
中の正レンズと負レンズの材質のアッベ数の平均値を各
々ν５Ｐ，ν５Ｎとしたとき、 １２＜ν５Ｎ−ν５Ｐ＜３５ なる条件を満足することを特徴とする請求項１のズーム
レンズ。4. The fifth group includes at least one negative lens and a positive lens each having a concave surface facing the object side, and the average value of Abbe numbers of the materials of the positive lens and the negative lens in the fifth group. each Nyu5P, when the ν5N, 12 <zoom lens according to claim 1, characterized by satisfying the ν5N-ν5P <35 following condition.
JP32140193A 1993-07-14 1993-11-26 Zoom lens Expired - Fee Related JP3144191B2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP32140193A JP3144191B2 (en) 1993-11-26 1993-11-26 Zoom lens
TW83106377A TW258791B (en) 1993-07-14 1994-07-13 Zoom lens
US08/735,571 US5691851A (en) 1993-07-14 1996-10-23 Zoom lens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP32140193A JP3144191B2 (en) 1993-11-26 1993-11-26 Zoom lens

Publications (2)

Publication Number Publication Date
JPH07151971A JPH07151971A (en) 1995-06-16
JP3144191B2 true JP3144191B2 (en) 2001-03-12

Family

ID=18132142

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
JP (1) JP3144191B2 (en)

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KR101233911B1 (en) 2003-12-05 2013-02-15 쓰리엠 이노베이티브 프로퍼티즈 컴파니 Wide-angle projection lens and optical engine for a projection display device
US7271964B2 (en) 2003-12-05 2007-09-18 3M Innovative Properties Company Projection display device for multimedia and wall display systems
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US9091844B2 (en) * 2012-06-25 2015-07-28 Karl Storz Imaging, Inc. Lens design forms with no 3rd or 5th order aberrations
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KR102421056B1 (en) 2015-11-20 2022-07-14 에스엘 주식회사 Automotive lamp

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