JP2506621B2 - Zoom lenses - Google Patents
Zoom lensesInfo
- Publication number
- JP2506621B2 JP2506621B2 JP63015409A JP1540988A JP2506621B2 JP 2506621 B2 JP2506621 B2 JP 2506621B2 JP 63015409 A JP63015409 A JP 63015409A JP 1540988 A JP1540988 A JP 1540988A JP 2506621 B2 JP2506621 B2 JP 2506621B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- group
- negative
- zoom
- positive
- 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 - Lifetime
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
- G02B15/177—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a negative front lens or group of lenses
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
- G02B15/1435—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative
- G02B15/143503—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative arranged -+-
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
- G02B15/1435—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative
- G02B15/143507—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative arranged -++
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Lenses (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明はズームレンズに関し、特に写真用カメラやビ
デオカメラ等に好適な全変倍範囲にわたり高い光学性能
を有した負の屈折力のレンズ群が先行する変倍比2.5程
度の３つのレンズ群を有するズームレンズに関するもの
である。Description: TECHNICAL FIELD The present invention relates to a zoom lens, and particularly to a lens group having a negative refractive power and having high optical performance over the entire zoom range suitable for a photographic camera, a video camera and the like. Relates to a zoom lens having three lens groups with a zoom ratio of about 2.5.
（従来の技術） 従来より写真用カメラやビデオカメラ等に好適な比較
的広画角の変倍比2.5程度のズームレンズとして所謂３
群タイプのズームレンズがあり、本出願人は例えば特開
昭58−186715号公報や特開昭59−36515号公報で提案し
ている。(Prior Art) A so-called 3 as a zoom lens having a relatively wide angle of view and a zoom ratio of about 2.5, which has been conventionally suitable for a photographic camera, a video camera, and the like.
There is a group type zoom lens, and the applicant of the present invention has proposed it, for example, in JP-A-58-186715 and JP-A-59-36515.
この３群タイプのズームレンズは物体側より順に負の
屈折力の第１群、正の屈折力の第２群、そして正、又は
負の屈折力の第３群の３つのレンズ群を有し、第１群と
第２群を移動させて変倍を行なっている。そして変倍比
２〜2.5倍程度の良好なる光学性能を有したレンズ全長
の比較的短い小型のズームレンズを得ている。This three-group type zoom lens has three lens groups, in order from the object side, a first group having negative refractive power, a second group having positive refractive power, and a third group having positive or negative refractive power. , The first group and the second group are moved to perform zooming. Then, a compact zoom lens having a relatively short overall lens length and a good zooming ratio of about 2 to 2.5 is obtained.
一般に３群ズームレンズにおいては、変倍に伴い移動
する第１群と第２群の全系に対する屈折力や各レンズ群
のレンズ構成を適切に設定しないと変倍に伴う収差変動
が増大し、高い光学性能を得るのが難しくなってくる。Generally, in a three-group zoom lens, if the refractive power for the entire system of the first group and the second group that moves with zooming and the lens configuration of each lens group are not properly set, aberration fluctuations due to zooming increase, It becomes difficult to obtain high optical performance.
例えば前述の各公報では物体側より順に第１群を正レ
ンズ、負レンズ、負レンズ、そして正レンズの４つのレ
ンズより構成したり、又は非球面を導入し、負レンズ、
負レンズ、そして正レンズの３つのレンズより構成し、
良好なる光学性能を得ている。For example, in each of the above-mentioned publications, the first group is composed of four lenses of a positive lens, a negative lens, a negative lens, and a positive lens in order from the object side, or an aspherical surface is introduced to form a negative lens,
It consists of three lenses, a negative lens and a positive lens,
Good optical performance is obtained.
（発明が解決しようとする問題点） 本発明は前述の各公報で提案した３群ズームレンズを
更に改良し、３群ズームレンズにおいて各レンズ群の屈
折力及びレンズ構成を適切に特定することにより変倍に
伴う収差変動が少なく、全変倍範囲にわたり高い光学性
能を有したレンズ全長の短い写真用カメラやビデオカメ
ラ等に好適な簡易な構成のズームレンズの提供を目的と
する。(Problems to be Solved by the Invention) The present invention is achieved by further improving the three-group zoom lens proposed in the above-mentioned publications, and by appropriately specifying the refractive power and lens configuration of each lens group in the three-group zoom lens. An object of the present invention is to provide a zoom lens having a simple structure suitable for a photographic camera, a video camera, or the like, which has a small variation in aberration due to zooming and has high optical performance over the entire zooming range and has a short overall lens length.
又、一般に非球面を導入する際、屈折率の高い材質に
施すと非球面の製作精度が厳しくなるので、なるべく低
屈折率の材質に施し、更に非球面を量産化する為にガラ
スモールドで成形する場合、レンズ径が大きいと成形が
難しくなるので、なるべくレンズ径の小さなレンズ面に
施すことにより、画面全体にわたり良好なる光学性能が
容易に得られるズームレンズの提供を目的とする。In general, when introducing an aspherical surface, if it is applied to a material with a high refractive index, the manufacturing accuracy of the aspherical surface will be strict, so apply it to a material with a low refractive index as much as possible, and mold it with a glass mold to mass produce the aspherical surface. In this case, if the lens diameter is large, molding becomes difficult. Therefore, it is an object of the present invention to provide a zoom lens in which good optical performance can be easily obtained over the entire screen by applying it to a lens surface having a lens diameter as small as possible.
（問題点を解決するための手段） 物体側より順に負の屈折力の第１群、正の屈折力の第
２群、そして第３群の３つのレンズ群を有し、前記第１
群と第２群を移動させて変倍を行うズームレンズにおい
て、前記第１群は負の第11レンズ、負の第12レンズ、そ
して正の第13レンズの３つのレンズを有し、物体側より
順に第ｉ番目のレンズ面の曲率半径をRi、前記第１群と
第２群の焦点距離を各々f1,f2、全系の望遠端の焦点距
離をFT、前記第11レンズと第12レンズの材質の屈折率を
各々N11,N12とするとき 0.6＜|f1/FT|＜0.72 …（１） 0.48＜f2/FT＜0.59 …（２） 1.7＜N11 …（３） 1.5＜N12＜1.65 …（４） 0.65＜R1/FT＜0.83 …（５） 0.25＜R2/FT＜0.31 …（６） −0.59＜R3/FT＜０ …（７） 0.64＜R4/FT＜0.8 …（８） 0.47＜R5/FT＜0.58 …（９） なる条件を満足することである。(Means for Solving the Problems) The first lens group has a negative refractive power, the second lens group has a positive refractive power, and the third lens group has three lens groups in order from the object side.
In the zoom lens for performing zooming by moving the second group and the second group, the first group has three lenses of a negative eleventh lens, a negative twelfth lens, and a positive thirteenth lens, In order, the radius of curvature of the i-th lens surface is Ri, the focal lengths of the first and second groups are f1 and f2, the focal length at the telephoto end of the entire system is FT, and the eleventh lens and the twelfth lens When the refractive index of the material is N11 and N12 respectively, 0.6 <| f1 / FT | <0.72… (1) 0.48 <f2 / FT <0.59… (2) 1.7 <N11… （3） 1.5 <N12 <1.65… (4) 0.65 <R1 / FT <0.83 (5) 0.25 <R2 / FT <0.31 (6) -0.59 <R3 / FT <0 (7) 0.64 <R4 / FT <0.8 (8) 0.47 < The condition is R5 / FT <0.58 (9).
（実施例） 第1,第２図は各々後述する本発明の数値実施例1,2の
望遠端におけるレンズ断面図である。図中Ｉは負の屈折
力の第１群であり、変倍に伴う像面変動を補正する為に
像面側に凸状の軌跡を有しながら移動すると共に合焦を
行なっている。IIは正の屈折力の第２群であり、広角端
から望遠端への変倍の際、単調に物体側方向に移動して
いる。IIIは固定の結像作用をする正、又は負の屈折力
の第３群である。Ｐ（R9）は開口絞り、SP（R18）は第
２群と第３群との間に配置した主に中間画角のフレアー
をカットする為のフレアカット絞りであり、変倍と共に
矢印の方向に移動させている。(Embodiment) FIGS. 1 and 2 are lens cross-sectional views at the telephoto end in Numerical Embodiments 1 and 2 of the present invention described later, respectively. In the figure, reference numeral I designates a first lens unit having a negative refractive power, which moves and has a focus while having a convex locus on the image plane side in order to correct the image plane variation due to zooming. The second lens group II has a positive refractive power, and moves monotonically toward the object side during zooming from the wide-angle end to the telephoto end. III is a third group having a positive or negative refractive power, which has a fixed image forming action. P (R9) is an aperture stop, and SP (R18) is a flare cut stop placed between the second group and the third group, mainly for cutting flare at an intermediate angle of view. Have moved to.
本実施例では前述の如く第1,第2,第３群の３つのレン
ズ群よりズームレンズを構成すると共に変倍径を構成す
る第1,第２群の屈折力を条件式（１），（２）の如く設
定し、更に第１群を所定形状の３つのレンズより構成す
ると共に各レンズの光学的諸定数を条件式（３）〜
（９）を満足するように特定することにより、変倍に伴
う収差変動を良好に補正し、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している。In this embodiment, as described above, the zoom lens is composed of the three lens groups of the first, second, and third groups, and the refractive powers of the first and second groups forming the variable magnification diameter are expressed by the conditional expression (1), Setting as shown in (2), the first group is composed of three lenses of a predetermined shape, and the optical constants of each lens are expressed by conditional expressions (3) to
By specifying so as to satisfy (9), it is possible to satisfactorily correct the aberration variation due to zooming and achieve a zoom lens having high optical performance over the entire zoom range.
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 meanings of the above conditional expressions will be described.
条件式（１）は第１群の屈折力に関し、上限値を越え
て第１群の屈折力が弱くなりすぎると第11レンズのレン
ズ径が増大し、レンズ系全体が大型化してくる。又、下
限値を越えて第１群の屈折力が強くなりすぎると広角側
での歪曲収差と望遠側での球面収差をバランス良く補正
するのが難しくなり、かつ変倍及び第１群でフォーカス
を行なう際に球面収差の変動が大きくなってくるので良
くない。Conditional expression (1) relates to the refracting power of the first group. If the refracting power of the first group becomes too weak beyond the upper limit value, the lens diameter of the eleventh lens increases and the entire lens system becomes large. If the lower limit is exceeded and the refractive power of the first lens unit becomes too strong, it becomes difficult to correct the distortion aberration on the wide-angle side and the spherical aberration on the telephoto side in a well-balanced manner. This is not good because the variation of spherical aberration becomes large when performing.
条件式（２）は第２群の屈折力に関し、上限値を越え
て第２群の屈折力が弱くなってくると所定の変倍比を得
る為に第２群の移動量を増加させねばならず、この結果
レンズ全長が長くなってくる。又、広角端で第１群と第
２群の間隔が増大する為、軸外光束を所定量確保する為
に第１群のレンズ径を増大させねばならずレンズ系全体
が大型化してくるので良くない。Conditional expression (2) relates to the refracting power of the second group. If the refracting power of the second group becomes weaker than the upper limit, the moving amount of the second group must be increased in order to obtain a predetermined zoom ratio. As a result, the total lens length becomes longer. Further, since the distance between the first group and the second group increases at the wide-angle end, the lens diameter of the first group must be increased in order to secure a predetermined amount of off-axis light flux. Not good.
下限値を越えて第２群の正の屈折力が強くなってくる
と変倍の際の第２群の移動量は少なくなるがバックフォ
ーカスが短かくなり、例えばレンズ系後方にクイックリ
ターンミラーを配置する為の空間を得るのが難しくなっ
てくる。If the positive refractive power of the second lens group becomes stronger beyond the lower limit, the amount of movement of the second lens group during zooming will decrease, but the back focus will become short. For example, a quick return mirror behind the lens system It becomes difficult to get a space to arrange them.
条件式（３）は第11レンズの材質の屈折率に関し、条
件式（４）は第12レンズの材質の屈折率に関するもので
ある。Conditional expression (3) relates to the refractive index of the material of the eleventh lens, and conditional expression (4) relates to the refractive index of the material of the twelfth lens.
条件式（３）の下限値若しくは条件式（４）の下限値
を越えて屈折率の低い材質を用いると、それに応じてレ
ンズ面の曲率を強くしなければならず、この結果各レン
ズ面で発生する諸収差、特に球面収差が増大し、かつ変
倍及びフォーカスの際の球面収差の変動が大きくなって
くるので良くない。If a material having a lower refractive index than the lower limit value of conditional expression (3) or the lower limit value of conditional expression (4) is used, the curvature of the lens surface must be increased accordingly. Aberrations generated, particularly spherical aberration, increase, and fluctuations in spherical aberration during zooming and focusing increase, which is not good.
条件式（４）の上限値を越えて屈折率の高い材質を用
いれば収差補正は有利となる。しかしながら後述するよ
うに第12レンズに非球面を施す際の非球面形状の製作誤
差の敏感度が高くなってくる。Aberration correction is advantageous if a material having a high refractive index is used that exceeds the upper limit of conditional expression (4). However, as will be described later, when an aspherical surface is applied to the twelfth lens, the sensitivity of manufacturing error of the aspherical surface shape becomes high.
特に大量生産を目的としたガラスモールドで非球面を
製作する場合等は僅かの形状誤差があっても光学性能が
著しく低下してくるのであまり高屈折率の材質は適当で
なく条件式（４）を満足する程度の材質を用いるのが良
い。Especially when manufacturing an aspherical surface with a glass mold for mass production, even if there is a slight shape error, the optical performance will drop significantly, so a material with a high refractive index is not appropriate and conditional expression (4) It is better to use a material that satisfies the above condition.
条件式（５）は第11レンズの物体側のレンズ面の曲率
半径に関し、上限値を越えて曲率半径が大きくなると撮
影画角２ω＝73.4゜程度の広画角化を図る際の広角側に
おける歪曲収差が負の方向に増大し、これを良好に補正
するのが難しくなってくる。又、下限値を越えて曲率半
径が小さくなると歪曲収差は比較的良好に補正されるが
レンズ径が増大してくるので良くない。Conditional expression (5) relates to the radius of curvature of the lens surface on the object side of the eleventh lens, and when the radius of curvature increases beyond the upper limit, the shooting angle of view 2ω = 73.4 ° The distortion aberration increases in the negative direction, and it becomes difficult to satisfactorily correct this. Further, when the radius of curvature becomes smaller than the lower limit value, the distortion aberration is corrected relatively well, but the lens diameter increases, which is not preferable.
条件式（６）は第11レンズの像面側のレンズ面の曲率
半径に関し、上限値を越えると第11レンズの負の屈折力
分担が減少し、これに対して第12レンズの負の屈折力分
担が増加し、この結果球面収差が多く発生すると共に中
間から望遠端への変倍に際してフレアーが多く発生して
くるので良くない。Conditional expression (6) relates to the radius of curvature of the image-side lens surface of the eleventh lens, and when the upper limit is exceeded, the negative refracting power share of the eleventh lens decreases, whereas the negative refraction of the twelfth lens decreases. This is not good because the force sharing increases, resulting in a large amount of spherical aberration and a large amount of flare during zooming from the middle to the telephoto end.
下限値を越えると第11レンズ自体の負の屈折力分担が
増加し、特に広角側での負の歪曲収差が増大し、これを
良好に補正するのが難しくなってくる。If the value goes below the lower limit, the negative refracting power share of the 11th lens itself increases, and particularly the negative distortion on the wide-angle side increases, which makes it difficult to satisfactorily correct it.
条件式（７）は第12レンズの物体側のレンズ面の曲率
半径に関する。Conditional expression (7) relates to the radius of curvature of the object-side lens surface of the twelfth lens.
上限値を越えて負の屈折力分担が少なくなると広角側
での歪曲収差は良好に補正されるが、その分第11レンズ
の像面側のレンズ面の負担が多くなり第11レンズの像面
側のレンズ面より発生する負の球面収差が大きくなり、
更に変倍に伴う収差変動が多くなってくるので良くな
い。下限値を越えると広角側での負の歪曲収差が増大
し、これを良好に補正するのが難しくなってくる。If the negative refracting power is less than the upper limit, distortion on the wide-angle side will be corrected well, but the load on the lens surface on the image side of the 11th lens will increase and the image surface of the 11th lens will increase. The negative spherical aberration generated from the lens surface on the side increases,
Furthermore, the variation of aberrations with zooming increases, which is not good. When the value goes below the lower limit, the negative distortion on the wide-angle side increases, and it becomes difficult to satisfactorily correct this.
条件式（８）は第12レンズの像面側のレンズ面の曲率
半径に関し、上限値を越えると他のレンズ面に対する負
の屈折力分担が強くなりすぎ広角側での負の歪曲収差を
良好に補正するのが難しくなってくる。下限値を越える
とこのレンズ面より生ずる球面収差（フレアー）が多く
なり、又変倍に伴う変動も大きくなってくるので良くな
い。Conditional expression (8) relates to the radius of curvature of the lens surface on the image side of the twelfth lens, and if the upper limit value is exceeded, the negative refracting power will be too much shared with other lens surfaces, and the negative distortion aberration on the wide angle side will be favorable. It becomes difficult to correct it. If the value goes below the lower limit, spherical aberration (flare) generated from this lens surface increases, and fluctuations due to zooming increase, which is not preferable.
条件式（９）は第13レンズの物体側のレンズ面の曲率
半径に関する。Conditional expression (9) relates to the radius of curvature of the object-side lens surface of the thirteenth lens.
本発明に係る３群ズームレンズにおいては負の屈折力
の第１群内の球面収差は主にこの第13レンズの物体側の
レンズ面で補正している。In the three-group zoom lens according to the present invention, the spherical aberration in the first group having a negative refractive power is mainly corrected by the object-side lens surface of the thirteenth lens.
上限値を越えると第１群内の球面収差の補正が不足
し、球面収差は補正過剰となってくる。そしてこのとき
の球面収差を補正する為に、例えば第12レンズと第13レ
ンズとの空気間隔を拡げると第11レンズの後側主点が物
体側へ移動し、ズームレンズ全体の近軸屈折力配置が大
きく変化して、所定の変倍比を得るのが難しくなってく
る。If the upper limit is exceeded, the spherical aberration in the first lens group is insufficiently corrected, and the spherical aberration is overcorrected. In order to correct the spherical aberration at this time, for example, if the air gap between the 12th lens and the 13th lens is expanded, the rear principal point of the 11th lens moves to the object side, and the paraxial refractive power of the entire zoom lens increases. The arrangement changes so much that it becomes difficult to obtain a predetermined zoom ratio.
下限値を越えると球面収差を全変倍範囲にわたりバラ
ンス良く補正するのが難しくなり、例えば広角端と望遠
端でバランス良く補正すると中間のズーム位置で著しく
補正過剰となってくるので良くない。When the value goes below the lower limit, it becomes difficult to correct spherical aberration in a good balance over the entire zoom range. For example, if it is corrected in a well-balanced manner at the wide-angle end and the telephoto end, the correction becomes significantly excessive at an intermediate zoom position, which is not good.
尚、本実施例において全変倍範囲にわたり歪曲収差を
更に良好に補正するには第12レンズの像面側のレンズ面
を周辺部にいくに従い正の屈折力が強まる形状の非球面
より構成するのが良い。即ち、軸外光束のが一番大き
くなるレンズ面に非球面を施すことにより歪曲収差を効
果的に補正している。このように本実施例では低屈折率
の材質より成る第12レンズに非球面を施すことにより、
非球面の製造誤差の敏感度を効果的に下げている。又、
これにより球面収差の発生量を少なくし全体的に良好な
る収差補正を行なっている。In this embodiment, in order to better correct distortion over the entire zoom range, the lens surface on the image side of the twelfth lens is composed of an aspherical surface having a positive refractive power that increases toward the periphery. Is good. That is, distortion is effectively corrected by forming an aspherical surface on the lens surface where the off-axis light flux becomes the largest. As described above, in the present embodiment, by applying an aspherical surface to the twelfth lens made of a low refractive index material,
It effectively reduces the sensitivity of manufacturing errors on the aspherical surface. or,
As a result, the amount of spherical aberration generated is reduced, and overall aberration correction is excellent.
本実施例において変倍に伴う収差変動を少なくし、更
に高い光学性能を得るには第２群を両レンズ面が凸面の
正レンズ、物体側に凸面を向けたメニスカス状の２つの
正レンズ、両レンズ面が凹面の負レンズ、そして両レン
ズ面が凸面の正レンズの５つのレンズより構成し、第３
群を負レンズと正レンズとを貼り合わせ全体として像面
側に凸面を向けたメニスカス状のレンズより構成するの
が良い。In the present embodiment, in order to reduce the aberration variation due to zooming and to obtain higher optical performance, the second lens group is a positive lens whose both lens surfaces are convex surfaces, and two meniscus positive lenses whose convex surfaces face the object side. It consists of five lenses, a negative lens with both concave lens surfaces and a positive lens with both convex lens surfaces.
It is preferable that the group is composed of a meniscus lens having a convex surface facing the image plane side as a whole by cementing a negative lens and a positive lens together.
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ν
ｉ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 shown. In the numerical example
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 gap from the object side, Ni and ν
i is the refractive index and Abbe number of the glass of the i-th lens in order from the object side.
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、B,C,Dを
各々非球面係数としたとき なる式で表わしている。The aspherical shape has an X axis along the optical axis and H along the direction perpendicular to the optical axis.
When the axis and the traveling direction of light are positive, R is the paraxial radius of curvature, and B, C, and D are aspherical coefficients, respectively. It is expressed by
数値実施例 １ Ｆ＝29〜67.9 FNO＝1:3.6〜4.6 ２ω＝73.4゜〜35.4゜ R 1＝ 48.61 D 1＝1.90 N 1＝1.83400 ν 1＝37.2 R 2＝ 18.94 D 2＝8.20 R 3＝−181.44 D 3＝2.00 N 2＝1.58313 ν 2＝59.4 R 4＝ 48.33 D 4＝1.90 （非球面） R 5＝ 35.69 D 5＝3.70 N 3＝1.80518 ν 3＝25.4 R 6＝ 151.92 D 6＝可変 R 7＝ 37.83 D 7＝3.10 N 4＝1.65160 ν 4＝58.6 R 8＝−312.56 D 8＝1.90 R 9＝ 絞り D 9＝0.70 R10＝ 24.59 D10＝3.85 N 5＝1.48749 ν 5＝70.2 R11＝ 50.97 D11＝0.28 R12＝ 20.69 D12＝4.40 N 6＝1.48749 ν 6＝70.2 R13＝ 64.81 D13＝1.07 R14＝−211.31 D14＝2.90 N 7＝1.84666 ν 7＝23.9 R15＝ 17.70 D15＝2.40 R16＝ 140.47 D16＝2.60 N 8＝1.75520 ν 8＝27.5 R17＝− 11.61 D17＝可変 R18＝フレア-カット D18＝可変 絞り R19＝− 45.00 D19＝1.80 N 9＝1.83400 ν 9＝37.2 R20＝− 70.97 D20＝2.30 N10＝1.60311 ν10＝60.7 R21＝−141.79 f1＝−45.02 f2＝ 36.27 非球面係数 Ｂ＝−3.866×10-6 Ｃ＝−1.883×10-9 Ｄ＝−3.390×10-11 数値実施例 ２ Ｆ＝29〜67.9 FNO＝1:3.6〜4.6 ２ω＝73.4゜〜35.4゜ R 1＝ 49.08 D 1＝1.90 N 1＝1.83400 ν 1＝37.2 R 2＝ 19.03 D 2＝8.25 R 3＝−129.03 D 3＝2.00 N 2＝1.58313 ν 2＝59.4 R 4＝ 48.66 D 4＝1.90 （非球面） R 5＝ 36.56 D 5＝3.90 N 3＝1.76182 ν 3＝26.6 R 6＝ 291.09 D 6＝可変 R 7＝ 36.97 D 7＝3.20 N 4＝1.62299 ν 4＝58.2 R 8＝−254.17 D 8＝1.90 R 9＝ 絞り D 9＝0.70 R10＝ 24.13 D10＝3.85 N 5＝1.48749 ν 5＝70.2 R11＝ 52.45 D11＝0.28 R12＝ 20.18 D12＝4.40 N 6＝1.48749 ν 6＝70.2 R13＝ 54.43 D13＝1.07 R14＝−362.59 D14＝2.90 N 7＝1.84666 ν 7＝23.9 R15＝ 17.06 D15＝2.40 R16＝ 120.31 D16＝2.60 N 8＝1.75520 ν 8＝27.5 R17＝− 39.49 D17＝可変 R18＝フレア-カット D18＝可変 絞り R19＝− 44.00 D19＝1.88 N 9＝1.83400 ν 9＝37.2 R20＝− 69.72 D20＝2.30 N10＝1.62299 ν10＝58.2 R21＝− 37.59 f1＝−44.92 f2＝ 36.27 非球面係数 Ｂ＝−3.649×10-6 Ｃ＝−2.302×10-9 Ｄ＝−2.643×10-11 （発明の効果） 本発明によれば３群タイプのズームレンズにおいて、
所定のレンズ群の屈折力及びレンズ構成を前述の如く設
定することにより、簡易な構成で変倍比2.5程度の高い
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。又第１群中の比較的レンズ径が小さく、かつ材質の
屈折率の比較的低い第12レンズの像面側のレンズ面に所
定形状の非球面を施せば全変倍範囲にわたり特に歪曲収
差を良好に補正した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。Numerical Example 1 F = 29 to 67.9 FNO = 1: 3.6 to 4.6 2ω = 73.4 ° to 35.4 ° R 1 = 48.61 D 1 = 1.90 N 1 = 1.83400 ν 1 = 37.2 R 2 = 18.94 D 2 = 8.20 R 3 = -181.44 D 3 = 2.00 N 2 = 1.58313 ν 2 = 59.4 R 4 = 48.33 D 4 = 1.90 (aspherical surface) R 5 = 35.69 D 5 = 3.70 N 3 = 1.80518 ν 3 = 25.4 R 6 = 151.92 D 6 = variable R 7 = 37.83 D 7 = 3.10 N 4 = 1.65160 ν 4 = 58.6 R 8 = -312.56 D 8 = 1.90 R 9 = Aperture D 9 = 0.70 R10 = 24.59 D10 = 3.85 N 5 = 1.48749 ν 5 = 70.2 R11 = 50.97 D11 = 0.28 R12 = 20.69 D12 = 4.40 N 6 = 1.48749 ν 6 = 70.2 R13 = 64.81 D13 = 1.07 R14 = -211.31 D14 = 2.90 N 7 = 1.84666 ν 7 = 23.9 R15 = 17.70 D15 = 2.40 R16 = 140.47 D16 = 2.60 N8 = 1.75520 ν8 = 27.5 R17 ＝ － 11.61 D17 ＝ Variable R18 ＝ Flare-Cut D18 ＝ Variable diaphragm R19 ＝ －45.00 D19 ＝ 1.80 N 9 ＝ 1.83400 ν 9 ＝ 37.2 R20 ＝ － 70.97 D20 ＝ 2.30 N10 ＝ 1.60311 ν10 = 60.7 R21 = -141.79 f 1 = −45.02 f 2 = 36.27 Aspheric coefficient B = −3.866 × 10 −6 C = −1.883 × 10 −9 D = −3.390 × 10 −11 Numerical Example 2 F = 29 to 67.9 FNO = 1: 3.6 ~ 4.6 2ω = 73.4 ° ~ 35.4 ° R 1 = 49.08 D 1 = 1.90 N 1 = 1.83400 ν 1 = 37.2 R 2 = 19.03 D 2 = 8.25 R 3 = -129.03 D 3 = 2.00 N 2 = 1.58313 ν 2 = 59.4 R 4 = 48.66 D 4 = 1.90 (aspherical surface) R 5 = 36.56 D 5 = 3.90 N 3 = 1.76182 ν 3 = 26.6 R 6 = 291.09 D 6 = variable R 7 = 36.97 D 7 = 3.20 N 4 = 1.62299 ν 4 = 58.2 R 8 = -254.17 D 8 = 1.90 R 9 = Aperture D 9 = 0.70 R10 = 24.13 D10 = 3.85 N 5 = 1.48749 ν 5 = 70.2 R11 = 52.45 D11 = 0.28 R12 = 20.18 D12 = 4.40 N 6 = 1.48749 ν 6 = 70.2 R13 = 54.43 D13 = 1.07 R14 = -362.59 D14 = 2.90 N 7 = 1.84666 ν 7 = 23.9 R15 = 17.06 D15 = 2.40 R16 = 120.31 D16 = 2.60 N 8 = 1.75520 ν 8 = 27.5 R17 =-39.49 D17 = Variable R18 = flare-cut D18 = variable aperture R19 = −44.00 D19 = 1.88 N 9 = 1.83400 ν 9 = 37.2 R20 = − 69.72 D20 = 2.30 N10 = 1.62299 ν10 = 58.2 R21 - 37.59 f 1 = −44.92 f 2 = 36.27 Aspherical coefficient B = −3.649 × 10 −6 C = −2.302 × 10 −9 D = −2.643 × 10 −11 (Effect of the invention) In a zoom lens,
By setting the refracting power of the predetermined lens group and the lens configuration as described above, it is possible to achieve a zoom lens having a high optical performance with a zoom ratio of about 2.5 with a simple configuration. Also, if an aspherical surface of a predetermined shape is applied to the image-side lens surface of the twelfth lens, which has a relatively small lens diameter in the first lens group and has a relatively low refractive index of the material, distortion will be caused particularly over the entire zoom range. A well-corrected zoom lens having high optical performance can be achieved.
第１図，第２図は本発明の数値実施例1,2のレンズ断
面、第３図，第４図は各々本発明の数値実施例1,2の諸
収差図である。収差図において（Ａ）は広角端、（Ｂ）
は中間、（Ｃ）は望遠端の収差である。Ｓはサジタル像
面、Ｍはメリディオナル像面である。I,II,IIIは各々第
1,第2,第３群、矢印は変倍の際の移動方向を示す。1 and 2 are lens cross sections of Numerical Embodiments 1 and 2 of the present invention, and FIGS. 3 and 4 are various aberration diagrams of Numerical Embodiments 1 and 2 of the present invention, respectively. In the aberration diagrams, (A) is the wide-angle end, (B)
Is intermediate, and (C) is aberration at the telephoto end. S is a sagittal image plane, and M is a meridional image plane. I, II, III are each
The first, second and third groups, and the arrows indicate the moving direction during zooming.
Claims (2)
屈折力の第２群、そして第３群の３つのレンズ群を有
し、前記第１群と第２群を移動させて変倍を行うズーム
レンズにおいて、前記第１群は負の第11レンズ、負の第
12レンズ、そして正の第13レンズの３つのレンズを有
し、物体側より順に第ｉ番目のレンズ面の曲率半径をR
i、前記第１群と第２群の焦点距離を各々f1,f2、全系の
望遠端の焦点距離をFT、前記第11レンズと第12レンズの
材質の屈折率を各々N11,N12とするとき 0.6＜|f1/FT|＜0.72 0.48＜f2/FT＜0.59 1.7＜N11 1.5＜N12＜1.65 0.65＜R1/FT＜0.83 0.25＜R2/FT＜0.31 −0.59＜R3/FT＜０ 0.64＜R4/FT＜0.8 0.47＜R5/FT＜0.58 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 positive refractive power, and a third lens unit in order from the object side. The first lens unit and the second lens unit are moved. In the zoom lens for changing the magnification, the first group includes a negative eleventh lens and a negative first lens.
It has 3 lenses, 12 lenses and the positive 13th lens, and the radius of curvature of the ith lens surface is R from the object side in order.
i, the focal lengths of the first group and the second group are f1 and f2, the focal length of the entire system at the telephoto end is FT, and the refractive indices of the materials of the eleventh lens and the twelfth lens are N11 and N12, respectively. When 0.6 <| f1 / FT | <0.72 0.48 <f2 / FT <0.59 1.7 <N11 1.5 <N12 <1.65 0.65 <R1 / FT <0.83 0.25 <R2 / FT <0.31 −0.59 <R3 / FT <0 0.64 <R4 A zoom lens characterized by satisfying the condition of /FT<0.8 0.47 <R5 / FT <0.58.
部にいくに従い正の屈折力が強まる形状の非球面である
ことを特徴とする請求項１記載のズームレンズ。2. The zoom lens according to claim 1, wherein the lens surface on the image plane side of the twelfth lens is an aspherical surface having a shape in which the positive refracting power is strengthened toward the peripheral portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63015409A JP2506621B2 (en) | 1988-01-26 | 1988-01-26 | Zoom lenses |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63015409A JP2506621B2 (en) | 1988-01-26 | 1988-01-26 | Zoom lenses |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01189622A JPH01189622A (en) | 1989-07-28 |
| JP2506621B2 true JP2506621B2 (en) | 1996-06-12 |
Family
ID=11887940
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63015409A Expired - Lifetime JP2506621B2 (en) | 1988-01-26 | 1988-01-26 | Zoom lenses |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2506621B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102129120B (en) * | 2010-01-14 | 2012-05-16 | 佛山普立华科技有限公司 | Projection lens |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5283693A (en) * | 1990-06-13 | 1994-02-01 | Minolta Camera Kabushiki Kaisha | Compact zoom lens system |
| JP3709000B2 (en) * | 1995-12-12 | 2005-10-19 | ペンタックス株式会社 | Super wide-angle zoom lens camera |
| US6124984A (en) * | 1996-12-13 | 2000-09-26 | Nikon Corporation | Variable magnification optical zoom lens system |
| JP2001208969A (en) * | 2000-01-25 | 2001-08-03 | Fuji Photo Optical Co Ltd | Wide-angle zoom lens |
| JP2002236254A (en) * | 2001-02-09 | 2002-08-23 | Sigma Corp | Zoom lens |
-
1988
- 1988-01-26 JP JP63015409A patent/JP2506621B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102129120B (en) * | 2010-01-14 | 2012-05-16 | 佛山普立华科技有限公司 | Projection lens |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01189622A (en) | 1989-07-28 |
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