JP2536167B2 - Zoom lenses - Google Patents
Zoom lensesInfo
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- JP2536167B2 JP2536167B2 JP1193773A JP19377389A JP2536167B2 JP 2536167 B2 JP2536167 B2 JP 2536167B2 JP 1193773 A JP1193773 A JP 1193773A JP 19377389 A JP19377389 A JP 19377389A JP 2536167 B2 JP2536167 B2 JP 2536167B2
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- positive
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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、特に口径比1.4程度の
大口径で、かつ変倍比15程度と高変倍でしかも全変倍範
囲にわたり良好なる光学性能を有した写真用カメラやビ
デオカメラ等に好適なズームレンズに関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a zoom lens, and in particular, it has a large aperture ratio of about 1.4 and a high zoom ratio of about 15 and is good over the entire zoom range. The present invention relates to a zoom lens having optical performance suitable for a photographic camera, a video camera and the like.
（従来の技術） 従来より写真用カメラやビデオカメラ等には大口径、
高変倍でしかも高い光学性能を有したズームレンズが要
求されている。(Conventional technology) Conventionally, large-diameter cameras and video cameras have been used.
There is a demand for a zoom lens that has a high zoom ratio and high optical performance.
このうち例えば民生用のビデオカメラではCCD等の撮
像素子の高画質化（画素数の増大化）、Ｓ−VHS方式、H
i−Band8mm方式等の記録方式の向上に伴う画面全体にわ
たる高画質化、例えば空間周波数で40本/mm程度の高解
像力を有するズームレンズが要求されている。Among these, for example, in a consumer video camera, image quality improvement (increasing the number of pixels) of an image sensor such as CCD, S-VHS method, H
With the improvement of recording methods such as the i-Band 8 mm method, there is a demand for a zoom lens having high image quality over the entire screen, for example, a high resolution of about 40 lines / mm at a spatial frequency.
又、物体側より順に合焦用の正の屈折力の第１群、変
倍機能を有する負の屈折力の第２群、変倍により変動す
る像面を補正する第３群、第３群からの光束を発散光又
は収歛光とする第４群、そして結像機能を有する第５群
より成る所謂５群ズームレンズにおいて高変倍化及び大
口径比化を図ろうとするとレンズ系全体が大型化してく
る。Further, from the object side, in order from the object side, a first group having a positive refracting power for focusing, a second group having a negative refracting power having a zooming function, a third group and a third group correcting an image plane fluctuated by zooming When a high zoom ratio and a large aperture ratio are attempted in a so-called five-group zoom lens including a fourth group that makes the light flux from the lens a divergent light or a converging light and a fifth group having an image forming function, the entire lens system becomes It becomes larger.
一般に５群ズームレンズにおいて高い光学性能を維持
しつつ、レンズ系全体の小型化及び高変倍化を図るには
レンズ系を構成する各レンズ群の光学的諸定数を適切に
設定することが重要となってくる。In general, it is important to properly set the optical constants of each lens group that constitutes the lens system in order to reduce the overall size of the lens system and achieve high zoom ratio while maintaining high optical performance in a 5-group zoom lens. Will be.
例えば単に各レンズ群の屈折力を強めてレンズ系全体
の小型化及び高変倍化を図ろうとすると、球面収差や画
面中心から画面周辺にかけてのコマ収差やサジタルハロ
ー収差等の高次の収差が多く発生し、更に変倍に伴う収
差変動が多くなり高い光学性能を得るのが難しくなって
くる。For example, simply increasing the refracting power of each lens group to downsize the entire lens system and increase the zoom ratio will cause spherical aberration and higher-order aberrations such as coma from the center of the screen to the periphery of the screen and sagittal halo aberration. A large number of them occur, and the variation of aberrations due to zooming increases, and it becomes difficult to obtain high optical performance.
又、現在ビデオカメラの撮像素子として多く用いられ
ているCCDやMOS等におけるカバー硝子の表面や撮像素子
の表面は一般に反射率が高く、この為これらの表面で反
射した光が撮影レンズのレンズ面やレンズ鏡筒等で反射
し、撮像素子に再入射して所謂ゴーストやフレアーを発
生する原因となっている。In addition, the surface of the cover glass and the surface of the image pickup device in CCDs and MOSs, which are often used as the image pickup device of video cameras at present, generally have high reflectance, so that the light reflected by these surfaces causes the lens surface of the photographing lens to be reflected. And a lens barrel or the like, which causes the so-called ghost and flare to re-enter the image sensor.
このようにビデオカメラに用いられる撮影レンズには
良好なる光学性能を有すると共にゴーストやフレアー等
の有害光を発生しないこと等、種々の事が要求されてい
る。As described above, various factors are required for the taking lens used in the video camera, such as having good optical performance and not generating harmful light such as ghost and flare.
（発明が解決しようとする問題点） 本発明は所謂５群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ことにより口径比F/1.4程
度と大口径変倍比15と高変倍比で、しかも全変倍範囲に
わたり高い光学性能を有すると共に例えばビデオカメラ
に適用したときに撮像素子面からの反射光によってゴー
ストやフレアー等が発生しないようにした小型のズーム
レンズの提供を目的とする。(Problems to be Solved by the Invention) The present invention is a so-called five-group zoom lens, in which the aperture ratio F / 1.4, the large aperture ratio 15 and the high aperture ratio are set by appropriately setting the lens configuration of each lens unit. Further, it is an object of the present invention to provide a small zoom lens having high optical performance over the entire zoom range and preventing generation of ghost or flare due to reflected light from the image sensor surface when applied to, for example, a video camera. .
（問題点を解決するための手段） 本発明のズームレンズは、物体側より順に合焦用の正
の屈折力の第１群、変倍機能を有する負の屈折力の第２
群、変倍により変動する像面を補正する負の屈折力の第
３群、該第３群からの発散光束を発散状態のまま射出さ
せる為の正の屈折力の第４群、そして結像機能を有する
第５群の５つのレンズ群を有し、該第１群は物体側に凸
面を向けた負のメニスカス状の第11レンズと両レンズ面
が凸面の第12レンズ、とを接合した貼り合わせレンズと
物体側に凸面を向けた正のメニスカス状の第13レンズを
有しており、該第２群は物体側に凸面を向けたメニスカ
ス状の負の第21レンズ、両レンズ面が凹面の第22レン
ズ、そして正の第23レンズを有しており、該第22レンズ
と第23レンズは貼り合わされており、該第３群は両レン
ズ面が凹面の負の第31レンズと両レンズ面が凸面若しく
は物体側に凸面を向けたメニスカス状の正の第32レンズ
とを接合した貼り合わせレンズを有しており、該第４群
は両レンズ面が凸面若しくは物体側のレンズ面が略平面
の正の第41レンズを有しており、該第１群から第３群を
通過した軸上光束の集束点から該第４群の前側主点まで
の距離をＬ、第ｉ群の焦点距離をfi、該第ｉ群の第ｊ番
目のレンズの媒質の屈折率とアッベ数を各々Ni,j,νi,
j、全系の広角端と望遠端における焦点距離を各々fw,fT
とするとき 1.05＜f4/L＜1.3 …………（ａ） 2.0＜(fT/f1)2＜2.4 …………（１） −1.97＜f2/fw＜−1.70 …………（２） 1.55＜N1,3＜1.75 …………（３） 21＜ν3,1−ν3,2＜33 …（４） 50＜ν4,1＜67 …………（５） なる条件を満足することを特徴としている。(Means for Solving Problems) A zoom lens according to the present invention comprises, in order from the object side, a first group of positive refracting power for focusing and a second group of negative refracting power having a zooming function.
Group, a third group having a negative refractive power that corrects an image surface that fluctuates due to zooming, a fourth group having a positive refractive power for emitting a divergent light beam from the third group in a divergent state, and imaging It has five lens groups of a fifth group having a function, and the first group cements a negative meniscus eleventh lens having a convex surface facing the object side and a twelfth lens having convex lens surfaces on both sides. It has a cemented lens and a positive meniscus thirteenth lens with the convex surface facing the object side, and the second group has a negative meniscus twenty-first lens with the convex surface facing the object side, and both lens surfaces are It has a concave 22nd lens and a positive 23rd lens, and the 22nd lens and the 23rd lens are cemented together, and the third lens group is a negative 31st lens with both lens surfaces concave. A cemented lens with a positive meniscus 32nd lens whose lens surface is convex or convex on the object side. The fourth lens unit has a positive 41st lens whose both lens surfaces are convex or whose object-side lens surface is substantially flat, and the fourth lens unit has an axis passing from the first lens unit to the third lens group. The distance from the focal point of the upper light flux to the front principal point of the fourth group is L, the focal length of the i-th group is fi, the refractive index and the Abbe number of the medium of the j-th lens of the i-th group are Ni, respectively. , j, νi,
j, the focal lengths at the wide-angle end and the telephoto end of the entire system are fw and fT, respectively.
1.05 <f4 / L <1.3 ………… (a) 2.0 <(fT / f1) 2 <2.4 ………… (1) −1.97 <f2 / fw <−1.70 ………… (2) 1.55 <N1,3 <1.75 (3) 21 <ν3,1−ν3,2 <33 (4) 50 <ν4,1 <67 ………… (5) It has a feature.
（実施例） 第１図は本発明の数値実施例１の広角端におけるレン
ズ断面図である。図中Ｉは合焦用の正の屈折力の第１
群、IIは変倍用の負の屈折力を第２群、IIIは変倍に伴
い変動する像面を補正する為の物体側に凸状の軌跡を有
して移動する負の屈折力の第３群、IVは第３群からの発
散光束を発散状態のまま射出させる為の正の屈折力の第
４群、Ｖは固定の結像機能を有する第５群、SPは固定の
絞りである。(Embodiment) FIG. 1 is a lens sectional view at a wide-angle end according to Numerical Embodiment 1 of the present invention. In the figure, I is the first positive refractive power for focusing.
Group II is a negative refractive power for zooming, and second group III is a negative refractive power that moves with a convex locus on the object side to correct the image plane that changes with zooming. Third group, IV is a fourth group having a positive refractive power for emitting the divergent light flux from the third group in a divergent state, V is a fifth group having a fixed image forming function, and SP is a fixed diaphragm. is there.
本実施例ではこのようなズームタイプにおいて、第４
群の屈折力を条件式（ａ）の如く特定することにより、
即ち第４群からの出射光束がやや発散傾向となるように
して絞り近傍にNDフィルター等を配置したときに、撮像
素子面からの反射光がこのフィルター面で反射して撮像
素子面上に再入射してゴーストやフレアー等が発生する
のを効果的に防止している。In this embodiment, in such a zoom type, the fourth type
By specifying the refractive power of the group as in conditional expression (a),
That is, when an ND filter or the like is arranged in the vicinity of the diaphragm so that the light flux emitted from the fourth group tends to be slightly divergent, the reflected light from the image pickup element surface is reflected by this filter surface and is reflected again on the image pickup element surface. It effectively prevents the incidence of ghosts and flares.
条件式（ａ）の上限値を越えて第４群の焦点距離f4が
長くなってくると（第４群の正の屈折力が弱くなってく
ると）第３群から射出してくる発散光束を第４群で収歛
させる作用が弱くなり、この結果、第４群からの射出光
束の発散状態が強くなり、ゴーストやフレアーを効果的
に除去するのが難しくなってくる。又、下限値を越えて
第４群の焦点距離f4が短くなってくると（第４群の正の
屈折力が強くなってくると）、第３群からの発散光束を
第４群で収歛しすぎてしまい、この結果、変倍に伴う収
差変動が大きくなってくるので良くない。When the focal length f4 of the fourth lens unit becomes longer than the upper limit of conditional expression (a) (when the positive refractive power of the fourth lens unit becomes weaker), the divergent light flux emitted from the third lens unit Is weakened in the fourth lens group, and as a result, the divergent state of the light flux emitted from the fourth lens group becomes strong, and it becomes difficult to effectively remove ghosts and flares. When the focal length f4 of the fourth lens unit becomes shorter than the lower limit value (the positive refractive power of the fourth lens unit becomes stronger), the divergent light flux from the third lens unit is collected by the fourth lens unit. It is too bad, and as a result, the variation of aberration with zooming becomes large, which is not good.
そして本実施例において変倍の際の収差変動を少なく
し、画面全体にわたり高い光学性能を得る為に第１群か
ら第４群のレンズ構成を前述の条件式（１）〜（５）を
満足するようにしている。Then, in the present embodiment, in order to reduce aberration variation during zooming and obtain high optical performance over the entire screen, the lens configurations of the first to fourth groups satisfy the above conditional expressions (1) to (5). I am trying to do it.
特に本実施例では第２群と第３群のレンズ形状やレン
ズの材質等を適切に設定することにより、高変倍化に伴
う諸収差の変動、例えば軸上色収差や倍率色収差の変
動、そして変倍系における残存収差、例えば球面収差や
コマ収差等をバランス良く補正している。更に第４群の
屈折力を第３群から入射してきた発散光束が発散状態で
射出するように設定することにより撮像素子やフィルタ
ー等からの反射光束が任意のレンズ面で反射して撮像素
子に再入射してゴーストやフレアーとなるのを効果的に
防止している。Particularly, in this embodiment, by appropriately setting the lens shapes of the second group and the third group, the materials of the lenses, and the like, variations in various aberrations due to high zooming, such as variations in axial chromatic aberration and chromatic aberration of magnification, and Residual aberrations in the variable power system, such as spherical aberration and coma, are corrected in good balance. Further, by setting the refracting power of the fourth lens unit so that the divergent light beam incident from the third lens unit exits in a divergent state, the light beam reflected from the image sensor, the filter, etc. is reflected by an arbitrary lens surface to the image sensor. It effectively prevents the ghost and flare from being re-incident.
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）は望遠端の全系の焦点距離に対する第１
群の焦点距離との比に関し、第１群の位置敏感度を適切
に設定するものである。上限値を越えて第１群の敏感度
が大きくなると組立精度が厳しくなり、製造が困難にな
り、又下限値を越えて第１群の焦点距離が長くなり敏感
度が弱くなりすぎると前玉レンズ径が増大してくるので
良くない。Conditional expression (1) is the first with respect to the focal length of the entire system at the telephoto end.
The position sensitivity of the first lens group is appropriately set with respect to the ratio to the focal length of the lens group. If the sensitivity of the first lens group becomes higher than the upper limit value, the assembling accuracy becomes strict and manufacturing becomes difficult, and if the focal length of the first lens group becomes too long and the sensitivity becomes too weak if the lower limit value is exceeded, the front lens This is not good because the lens diameter increases.
条件式（２）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、主に変倍による収差変動を
良好に補正する為のものである。上限値を越えて第２群
の焦点距離が長くなるとレンズ全長が長くなり、又条件
式（１）のもとで越えると第１群と第２群が物理的に干
渉しやすくなってくる。逆に下限値を越えると変倍に伴
う収差変動が大きくなり、光学性能が低下してくるので
良くない。Conditional expression (2) 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 mainly for favorably correcting aberration fluctuations due to zooming. If the focal length of the second lens group becomes longer than the upper limit value, the total lens length becomes long, and if it exceeds the conditional expression (1), the first lens group and the second lens group tend to physically interfere with each other. On the other hand, if the value goes below the lower limit, the variation in aberration due to zooming becomes large and the optical performance deteriorates.
条件式（３）は第１群の第13レンズの材質の屈折率に
関するものであり、主に歪曲収差をバランス良く補正す
る為の条件である。上限値を越えると広角端における歪
曲収差が増大し、又下限値を越えると望遠端においてハ
ローが増大してくるので良くない。The conditional expression (3) relates to the refractive index of the material of the 13th lens of the first group, and is mainly a condition for correcting distortion in a well-balanced manner. If the value exceeds the upper limit, distortion at the wide-angle end increases, and if it exceeds the lower limit, the halo increases at the telephoto end, which is not good.
条件式（４）は第３群中の負の第31レンズと正の第32
レンズの材質のアッベ数の差に関し、主に変倍に伴う軸
上色収差の変動を良好に補正する為の条件である。上限
値を越えると変倍に伴う変動量は少なくなるが、全体に
軸上色収差がアンダーになってくる。逆に下限値を越え
ると軸上色収差の変動量が大きくなり良好なる補正が困
難になってくる。The conditional expression (4) is the negative 31st lens and the positive 32nd lens in the third lens group.
Regarding the difference in Abbe number of the material of the lens, it is a condition for favorably correcting the fluctuation of the axial chromatic aberration mainly due to the magnification change. When the value exceeds the upper limit, the amount of variation due to zooming is reduced, but the axial chromatic aberration is undersized overall. On the other hand, when the value goes below the lower limit, the amount of fluctuation of the axial chromatic aberration becomes large, and it becomes difficult to perform good correction.
条件式（５）は第４群の正の第41レンズの材質のアッ
ベ数に関し、主に軸上色収差を良好に補正する為の条件
である。条件式（４）により軸上色収差の変動量を少な
くし、条件式（５）により軸上色収差を適切な値に設定
している。上限値を越えると軸上色収差が全体にオーバ
ーになり、又下限値を越えるとアンダーになってくるの
で良くない。Conditional expression (5) relates to the Abbe number of the material of the positive first lens group 41 of the fourth lens group, and is a condition for mainly correcting the axial chromatic aberration well. The conditional expression (4) reduces the variation amount of the axial chromatic aberration, and the conditional expression (5) sets the axial chromatic aberration to an appropriate value. If the upper limit value is exceeded, the axial chromatic aberration will be entirely over, and if the lower limit value is exceeded, it will be under.
次に本実施例において撮像素子の表面からの反射光に
基づくゴーストやフレアー光を効果的に防止する為には
第５群のレンズ構成の一部を次の如く設定するのが良
い。Next, in this embodiment, in order to effectively prevent the ghost and flare light based on the reflected light from the surface of the image pickup device, it is preferable to set a part of the lens configuration of the fifth group as follows.
前記第５群は物体側から順に両レンズ面が凸面の第51
レンズ、物体側に強い屈折面を向けた両レンズ面が凹面
の負の第52レンズ、物体側に強い屈折面を向けた正の第
53レンズ、両レンズ面が凹面若しくは像面側に強い屈折
面の凹面を向けたメニスカス状の負の第54レンズ、両レ
ンズ面が凸面の第55レンズ、そして物体側に強い屈折面
の凸面を向けた正の第56レンズの６つのレンズを有して
おり、該第５群の第ｉ番目のレンズ面の曲率半径をR5,i
としたとき 0.02＜fw/R5,4＜0.03 …………（６） −0.03＜fw/R5,7＜0.03 …………（７） 50＜（ν5,1＋ν5,3）/2＜65 …………（８） なる条件を満足することである。The fifth lens group is the first lens group in which both lens surfaces are convex surfaces in order from the object side.
The lens, the negative 52nd lens where both lens surfaces with the strong refracting surface facing the object side are concave, and the positive second lens with the strong refracting surface facing the object side.
53 lens, a negative meniscus 54th lens with both lens surfaces concave or a strong refractive concave surface toward the image side, a 55th lens with both lens surfaces convex, and a strong refractive convex surface on the object side. 6 lenses of the positive 56th lens directed to the lens, and the radius of curvature of the ith lens surface of the 5th group is R5, i
0.02 <fw / R5,4 <0.03 ………… (6) −0.03 <fw / R5,7 <0.03 ………… (7) 50 <(ν5,1 ＋ ν5,3) / 2 <65… … (8) To satisfy the following condition.
条件式（６）は第５群の物体側から数えて第４番目の
レンズ面の曲率半径に関し、主にコマ収差の発生を少な
くし、かつゴーストやフレアー等の有害光の原因となる
撮像素子と、前記レンズ面との反射光による再結像位置
を撮影レンズ側へ結像させる為のものである。上限値を
越えて曲率が小さくなると内向性コマ収差が発生し、こ
れを他のレンズ面での補正するのが困難である。下限値
を越えて曲率が大きくなると、撮像素子とレンズ面との
反射光の再結像位置が撮像レンズの結像面近傍、あるい
は結像面より撮像レンズの遠方方向に位置して有害光と
なってくるので良くない。Conditional expression (6) relates to the radius of curvature of the fourth lens surface counting from the object side of the fifth lens group, mainly reduces coma aberration and causes harmful light such as ghost and flare. And the re-imaging position by the reflected light from the lens surface is focused on the photographing lens side. When the curvature becomes smaller than the upper limit, inward coma occurs, which is difficult to correct on other lens surfaces. When the lower limit is exceeded and the curvature becomes large, the re-imaging position of the reflected light between the image sensor and the lens surface is located near the image forming surface of the image capturing lens or in the direction farther from the image forming lens than the image forming surface, and harmful light is emitted. It is not good because it will be.
条件式（７）は条件式（６）と同様撮像素子と前記レ
ンズ面との反射光に基づく再結像位置を撮像レンズ側へ
結像させ、かつ像面湾曲とコマ収差をバランス良く補正
する為の条件である。上限値を越えて曲率が小さくなる
と外向性コマ収差が多く発生し、又、下限値を越えて曲
率が大きくなると像面がアンダーになってくるので良く
ない。Conditional expression (7) is similar to conditional expression (6) in that the re-imaging position based on the reflected light from the imaging device and the lens surface is imaged on the imaging lens side, and field curvature and coma are corrected in a well-balanced manner. This is a condition for If the curvature exceeds the upper limit and the curvature becomes small, a large amount of outward coma aberration occurs, and if the curvature exceeds the lower limit, the image surface becomes under, which is not preferable.
条件式（８）は第５群の正の第51レンズと正の第53レ
ンズの材質のアッベ数に関し、変倍部からの残存色収差
を良好に補正する為のものである。下限値を越えてアッ
ベ数が小さくなると広角側で軸上色収差が補正不足とな
り、又上限値を越えてアッベ数が大きくなると望遠側で
軸上色収差が補正過剰となってくる。The conditional expression (8) relates to the Abbe number of the material of the positive 51st lens and the positive 53rd lens of the fifth lens group, and is for correcting the residual chromatic aberration from the zooming portion well. If the Abbe's number becomes smaller than the lower limit, the axial chromatic aberration will be undercorrected on the wide-angle side, and if the Abbe's number becomes larger if the upper limit is exceeded, the axial chromatic aberration will be overcorrected on the telephoto side.
以上の説明で像面側に強い屈折面とは他方の面、即ち
物体側のレンズ面の屈折力に比べての意味である。物体
側に強い屈折面も同様である。In the above description, the strong refracting surface on the image side means the other surface, that is, the refracting power of the lens surface on the object side. The same applies to a refracting surface that is strong on the object side.
尚、本実施例において全変倍範囲にわたり更に良好な
る光学性能を得るには第５群のレンズ構成を次の如く設
定すのが良い。In this embodiment, in order to obtain better optical performance over the entire zoom range, it is preferable to set the lens configuration of the fifth group as follows.
即ち、前記第５群の第ｉ番目のレンズ厚又は空気間隔
をD5,iとするとき −1.23＜R5,1＜R5,3＜−0.99 …………（９） 2.75＜R5,5/fw＜3.49 …（10） 1.87＜R5,8/fw＜2.09 …（11） 2.00＜R5,9/R5,11＜4.07 …………（12） 0.13＜D5,2/fw＜0.19 …（13） 1.90＜D5,6/fw＜2.41 …（14） 0.11＜D5,8/fw＜0.15 …（15） なる条件を満足することである。That is, when the ith lens thickness or the air gap of the fifth group is D5, i -1.23 <R5,1 <R5,3 <-0.99 (9) 2.75 <R5,5 / fw <3.49… (10) 1.87 <R5,8 / fw <2.09… (11) 2.00 <R5,9 / R5,11 <4.07 ……… (12) 0.13 <D5,2 / fw <0.19… (13) 1.90 <D5,6 / fw <2.41 (14) 0.11 <D5,8 / fw <0.15 (15).
条件式（９）は第５群中の物体側から数えて第１番目
のレンズ面の曲率半径と第３番目のレンズ面の曲率半径
の比に関するもので、主に球面収差を適切に補正する為
の条件である。下限値を越えると球面収差がアンダーに
なり、又、上限値を越えるとオーバーになる。Conditional expression (9) relates to the ratio of the radius of curvature of the first lens surface to the radius of curvature of the third lens surface counted from the object side in the fifth lens group, and mainly corrects spherical aberration appropriately. This is a condition for If the lower limit is exceeded, the spherical aberration will be under, and if the upper limit is exceeded, the spherical aberration will be over.
条件式（10）は球面収差を極力発生させずに光束を効
率良く収束させる為の条件である。下限値を越えると球
面収差が著しく多く発生し、又、上限値を越えると収束
効果が不十分になり、レンズ全長の増加を招くので良く
ない。Conditional expression (10) is a condition for efficiently converging the light flux without generating spherical aberration as much as possible. If the lower limit is exceeded, a large amount of spherical aberration will occur, and if the upper limit is exceeded, the focusing effect will be insufficient and the overall lens length will be increased, which is not preferable.
条件式（11）はコマ収差をできるだけ発生させずにレ
ンズ系全体がコンパクトで、かつテレセントリックな光
学系を良好に構成する為の条件である。下限値を越える
と外向性コマ収差が著しく多く発生し、これを良好に補
正するのが困難になり、又、上限値を越えてテレセント
リックな光学系を達成するとレンズ全長が増大してくる
ので良くない。Conditional expression (11) is a condition for favorably configuring a telecentric optical system in which the entire lens system is compact and does not generate coma as much as possible. If the value goes below the lower limit, a large amount of outward coma will occur, which will be difficult to correct well, and if the value exceeds the upper limit and a telecentric optical system is achieved, the total lens length will increase. Absent.
条件式（12）は像面湾曲とコマ収差をバランス良く補
正する為の条件である。下限値を越えると像面湾曲はア
ンダーになり、更に内向性コマ収差が多く発生し、又、
上限値を越えると像面湾曲はオーバーになり、更に外向
性コマ収差が多く発生し、これを良好に補正するのが困
難になってくる。Conditional expression (12) is a condition for correcting field curvature and coma aberration in a well-balanced manner. If the lower limit is exceeded, the curvature of field will be under, and more inward coma will occur.
When the value exceeds the upper limit, the curvature of field becomes excessive, and more outward coma aberration occurs, which makes it difficult to correct it favorably.
条件式（13）は主に球面収差及び非点収差をバランス
良く補正する為の条件である。下限値を越えると非点収
差が大きくなり、又、上限値を越えると高次の球面収差
が発生する。Conditional expression (13) is a condition for correcting spherical aberration and astigmatism in good balance. When the value goes below the lower limit, astigmatism becomes large, and when it goes beyond the upper limit, high-order spherical aberration occurs.
条件式（14）は第53レンズ群と第54レンズ群の間隔に
関し、軸上収差と軸外収差の両方をバランス良く補正
し、かつテレセントリックな光学系を達成する為の条件
である。下限値を越えると非点収差、コマ収差等の軸外
収差が悪化し、テレセントリックな光学系を達成するの
が困難になり、又、上限値を越えると球面収差等の軸上
収差が発生する。Conditional expression (14) relates to the distance between the 53rd lens group and the 54th lens group, and is a condition for correcting both axial aberration and off-axis aberration in a well-balanced manner and for achieving a telecentric optical system. If the lower limit is exceeded, off-axis aberrations such as astigmatism and coma will worsen, making it difficult to achieve a telecentric optical system.If the upper limit is exceeded, axial aberrations such as spherical aberration will occur. .
条件式（15）は主にコマ収差と歪曲収差を補正する為
の条件である。下限値を越えると外向性コマ収差が発生
し、これを良好に補正するのが困難になり、又、上限値
を越えると広角端でたる型の歪曲収差が多く発生してく
るので良くない。Conditional expression (15) is a condition for mainly correcting coma and distortion. Exceeding the lower limit causes outward coma, which is difficult to correct well, and exceeding the upper limit causes a lot of barrel distortion at the wide-angle end, which is not preferable.
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。R29,R30はフェースプレートや
フィルター等である。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. R29 and R30 are face plates and filters.
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.
尚、以上の各実施例において第４群を２つの正のレン
ズより構成しても良く、これによれば変倍部の残存収差
を更に良好に補正することができる。 In each of the above embodiments, the fourth lens unit may be composed of two positive lenses, which allows the residual aberration of the variable power portion to be corrected even better.
（発明の効果） 以上のように本発明によれば５群ズームレンズにおい
て各レンズ群のレンズ構成を前述の如く設定することに
よりＦナンバー1.4と大口径比、変倍比15と高変倍比で
全変倍範囲にわたり高い光学性能を有し、しかもビデオ
カメラ等においては撮像素子表面からの反射光に基づく
ゴーストやフレアー等の有害光を効果的に除去すること
のできる、写真用カメラやビデオカメラに好適なズーム
レンズを達成することが出来る。(Effect of the Invention) As described above, according to the present invention, by setting the lens configuration of each lens group in the five-group zoom lens as described above, an F number of 1.4 and a large aperture ratio, a zoom ratio of 15 and a high zoom ratio. With high optical performance over the entire zoom range, it is possible to effectively remove harmful light such as ghosts and flares due to the reflected light from the image sensor surface in video cameras and the like. A zoom lens suitable for a camera can be achieved.
第１図は本発明の数値実施例１のレンズ断面図、第２図
〜第４図は各々本発明の数値実施例１〜３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）は望遠端での収差図である。 図中、I,II,III,IV,Vは各々第1,第2,第3,第4,第５群、
ΔＭはメリディオナル像面、ΔＳはサジタル像面、ｄは
ｄ線、ｇはｇ線、SPは絞りである。FIG. 1 is a lens cross-sectional view of Numerical Embodiment 1 of the present invention, and FIGS. 2 to 4 are aberration diagrams of Numerical Embodiments 1 to 3 of the present invention, respectively. In the aberration diagram, (A) is the wide-angle end, (B) is the middle,
FIG. 6C is an aberration diagram at the telephoto end. In the figure, I, II, III, IV and V are the first, second, third, fourth and fifth groups,
ΔM is a meridional image plane, ΔS is a sagittal image plane, d is a d-line, g is a g-line, and SP is a diaphragm.
Claims (3)
群、変倍機能を有する負の屈折力の第２群、変倍により
変動する像面を補正する負の屈折力の第３群、該第３群
からの発散光束を発散状態のまま射出させる為の正の屈
折力の第４群、そして結像機能を有する第５群の５つの
レンズ群を有し、該第１群は物体側に凸面を向けた負の
メニスカス状の第11レンズと両レンズ面が凸面の第12レ
ンズ、とを接合した貼り合わせレンズと物体側に凸面を
向けた正のメニスカス状の第13レンズを有しており、該
第２群は物体側に凸面を向けたメニスカス状の負の第21
レンズ、両レンズ面が凹面の第22レンズ、そして正の第
23レンズを有しており、該第22レンズと第23レンズは貼
り合わされており、該第３群は両レンズ面が凹面の負の
第31レンズと両レンズ面が凸面若しくは物体側に凸面を
向けたメニスカス状の正の第32レンズとを接合した貼り
合わせレンズを有しており、該第４群は両レンズ面が凸
面若しくは物体側のレンズ面が略平面の正の第41レンズ
を有しており、該第１群から第３群を通過した軸上光束
の集束点から該第４群の前側主点までの距離をＬ、第ｉ
群の焦点距離をfi、該第ｉ群の第ｊ番目のレンズの媒質
の屈折率とアッベ数を各々Ni,j,νi,j、全系の広角端と
望遠端における焦点距離を各々fw,fTとするとき 1.05＜f4/L＜1.3 2.0＜(fT/f1)2＜2.4 −1.97＜f2/fw＜−1.70 1.55＜N1,3＜1.75 21＜ν3,1−ν3,2＜33 50＜ν4,1＜67 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 positive refractive power for focusing in order from the object side.
Group, a second group having a negative refracting power having a variable power function, a third group having a negative refracting power for correcting an image plane that fluctuates due to zooming, and a divergent light beam from the third group is emitted in a diverging state. The fifth lens unit has a fourth lens unit having a positive refracting power and a fifth lens unit having an image forming function. The first lens unit has a negative meniscus eleventh lens element having a convex surface directed toward the object side. It has a cemented lens in which a twelfth lens having both convex lens surfaces, and a positive meniscus thirteenth lens having a convex surface facing the object side, and the second group has a convex surface facing the object side. Meniscus negative 21st
The lens, the 22nd lens with concave lens surfaces, and the positive 2nd lens
The second lens has a 23 lens, and the 22nd lens and the 23rd lens are cemented together. The third lens group has a negative 31st lens whose both lens surfaces are concave and both lens surfaces are convex or convex on the object side. And a cemented lens cemented with a positive meniscus-shaped thirty-second lens, and the fourth lens group has a positive-41st lens whose both lens surfaces are convex or whose object-side lens surface is substantially flat. And the distance from the focal point of the axial light flux passing through the first group to the third group to the front principal point of the fourth group is L, i-th
The focal length of the group is fi, the refractive index and the Abbe number of the medium of the j-th lens of the i-th group are Ni, j, νi, j, and the focal lengths at the wide-angle end and the telephoto end are fw, respectively. fT 1.05 <f4 / L <1.3 2.0 <(fT / f1) 2 <2.4 −1.97 <f2 / fw <−1.70 1.55 <N1,3 <1.75 21 <ν3,1−ν3,2 <33 50 < A zoom lens characterized by satisfying the condition of ν4,1 <67.
凸面の第51レンズ、物体側に強い屈折面を向けた両レン
ズ面が凹面の負の第52レンズ、物体側に強い屈折面を向
けた正の第53レンズ、両レンズ面が凹面若しくは像面側
に強い屈折面の凹面を向けたメニスカス状の負の第54レ
ンズ、両レンズ面が凸面の第55レンズ、そして物体側に
強い屈折面の凸面を向けた正の第56レンズの６つのレン
ズを有しており、該第５群の第ｉ番目のレンズ面の曲率
半径をR5,iとしたとき 0.02＜fw/R5,4＜0.03 −0.03＜fw/R5,7＜0.03 50＜（ν5,1＋ν5,3）/2＜65 なる条件を満足することを特徴とする請求項１記載のズ
ームレンズ。2. The fifth lens group, in which, in order from the object side, the 51st lens has convex lens surfaces on both sides, the 52nd lens has a concave surface on both lens surfaces and has a strong refraction surface on the object side, and strong refraction on the object side. The positive 53rd lens with the surface facing, the both surfaces are concave or the meniscus negative 54th lens with the concave surface of the strong refractive surface facing the image side, the 55th lens with both lens surfaces convex, and the object side It has 6 lenses of positive 56th lens with the convex surface of the strong refracting surface facing toward, and the radius of curvature of the ith lens surface of the 5th group is R5, i 0.02 <fw / R5 2. The zoom lens according to claim 1, wherein the condition: 4 <0.03 −0.03 <fw / R5,7 <0.03 50 <(ν5,1 + ν5,3) / 2 <65 is satisfied.
間隔をD5,iとするとき −1.23＜R5,1/R5,3＜−0.99 2.75＜R5,5/fw＜3.49 1.87＜R5,8/fw＜2.09 2.00＜R5,9/R5,11＜4.07 0.13＜D5,2/fw＜0.19 1.90＜D5,6/fw＜2.41 0.11＜D5,8/fw＜0.15 なる条件を満足することを特徴とする請求項２記載のズ
ームレンズ。3. When the i-th lens thickness of the fifth lens unit or the air gap is D5, i -1.23 <R5,1 / R5,3 <-0.99 2.75 <R5,5 / fw <3.49 1.87 < R5,8 / fw <2.09 2.00 <R5,9 / R5,11 <4.07 0.13 <D5,2 / fw <0.19 1.90 <D5,6 / fw <2.41 0.11 <D5,8 / fw <0.15 The zoom lens according to claim 2, wherein
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1193773A JP2536167B2 (en) | 1989-07-26 | 1989-07-26 | Zoom lenses |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1193773A JP2536167B2 (en) | 1989-07-26 | 1989-07-26 | Zoom lenses |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0356915A JPH0356915A (en) | 1991-03-12 |
| JP2536167B2 true JP2536167B2 (en) | 1996-09-18 |
Family
ID=16313568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1193773A Expired - Fee Related JP2536167B2 (en) | 1989-07-26 | 1989-07-26 | Zoom lenses |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2536167B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001264614A (en) | 2000-03-15 | 2001-09-26 | Fuji Photo Optical Co Ltd | Zoom lens |
-
1989
- 1989-07-26 JP JP1193773A patent/JP2536167B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0356915A (en) | 1991-03-12 |
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