JP2607957B2 - Compact zoom lens - Google Patents
Compact zoom lensInfo
- Publication number
- JP2607957B2 JP2607957B2 JP1150588A JP15058889A JP2607957B2 JP 2607957 B2 JP2607957 B2 JP 2607957B2 JP 1150588 A JP1150588 A JP 1150588A JP 15058889 A JP15058889 A JP 15058889A JP 2607957 B2 JP2607957 B2 JP 2607957B2
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- refractive power
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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、レンズシャッターカメラ用のコンパクトな
変倍レンズに関するものである。Description: FIELD OF THE INVENTION The present invention relates to a compact variable power lens for a lens shutter camera.
［従来の技術］ 近年、カメラの小型化に伴って変倍レンズも小型軽量
化が図られている。特に、レンズ交換のできないレンズ
シャッターカメラにおいて、コンパクトでしかも変倍比
が２以上の変倍レンズを備えたカメラが求められてい
る。[Related Art] In recent years, as the size of cameras has been reduced, the size and weight of variable power lenses have also been reduced. In particular, there is a demand for a compact lens shutter camera having a variable power lens having a variable power ratio of 2 or more.
このような小型軽量化の要求を満足するようにした変
倍レンズとして、正の屈折力を前群と負の屈折力の後群
とよりなり、両群間の間隔を変化させて変倍するものが
知られている。しかしこのタイプの変倍レンズは、倍率
が１よりも大である負の屈折力を有する後群により変倍
が行なわれるので、２以上の大きな変倍比を得ることが
難しい。As a variable power lens that satisfies such demands for miniaturization and weight reduction, it has a positive refractive power consisting of a front group and a negative refractive power rear group, and changes the distance between both groups to change the magnification. Things are known. However, in this type of variable power lens, it is difficult to obtain a large variable power ratio of 2 or more since the variable power is performed by a rear group having a negative refractive power whose magnification is larger than 1.
この問題を解決し高変倍率化をはかった変倍レンズと
して、特開昭63−159818号，特開昭63−161423号号公報
に記載されたレンズ系があるが、小型軽量化の点で十分
満足し得るものではない。Lens systems described in JP-A-63-159818 and JP-A-63-161423 are known as variable power lenses which solve this problem and have a high magnification. However, in view of reduction in size and weight. It is not enough.
一般にレンズ系を小型化する場合、レンズ面の曲率半
径を小さくして屈折力を強めればよい。しかしその場合
各面で発生する収差が大きくなりすぎて、レンズ枚数を
増やさなければ補正出来なくなり、結果的には小型軽量
化が図れない。In general, when the size of the lens system is reduced, the radius of curvature of the lens surface may be reduced to increase the refractive power. However, in that case, the aberration generated on each surface becomes too large and cannot be corrected unless the number of lenses is increased. As a result, reduction in size and weight cannot be achieved.
また、変倍レンズにおいては、各群独立に色収差を補
正しなければならず、そのためには各群が少なくとも１
枚の正レンズと１枚の負レンズを有する構成にするのが
一般的である。しかし、その場合相反する屈折力を有す
るために、レンズ系が所望の屈折力を得るには個々のレ
ンズの屈折力を必要以上に強くしなければならず結果的
に収差の発生量が大になり、そのため高変倍率の変倍レ
ンズを小型化するのは困難である。同じ符号の屈折力の
もつレンズのみで各群で構成すれば小型化は可能である
が、均質レンズ系の場合、色収差の補正上不可能であ
る。Further, in the variable power lens, it is necessary to correct the chromatic aberration independently for each group.
It is common to have a configuration having one positive lens and one negative lens. However, in this case, since the lens systems have contradictory refractive powers, the refractive power of each lens must be increased more than necessary in order for the lens system to obtain a desired refractive power. Therefore, it is difficult to reduce the size of a high-magnification lens. If each group is composed of only lenses having the same sign of refractive power, the size can be reduced, but in the case of a homogeneous lens system, it is impossible to correct chromatic aberration.
又、不均質を用いた従来例として特開昭61−148414
号、特開昭61−295524号公報に記載された変倍レンズが
知られている。それはレンズシャッターカメラ用の変倍
レンズで、最も物体側の負のレンズ群が負レンズのみで
構成されている。これらの変倍レンズはいずれも変倍比
が1.5〜２であって、高変倍率とは言えず、レンズ系の
全長が大でコンパクトとは言えない。A conventional example using heterogeneity is disclosed in Japanese Patent Application Laid-Open No. 61-148414.
And a variable power lens described in JP-A-61-295524 are known. It is a variable power lens for a lens shutter camera, and the negative lens group closest to the object side is composed of only negative lenses. Each of these variable power lenses has a variable power ratio of 1.5 to 2, cannot be said to be a high variable power, and cannot be said to be compact because the total length of the lens system is large.
［発明が解決しようとする課題］ 本発明は、高変倍率であるにも拘らず、広角端から望
遠鏡まで諸収差が十分に補正されしかもレンズ系の全長
の極めて短いコンパクトな変倍レンズを提供することを
目的としている。[Problems to be Solved by the Invention] The present invention provides a compact variable-power lens in which various aberrations from the wide-angle end to the telescope are sufficiently corrected, and the overall length of the lens system is extremely short despite high magnification. It is intended to be.
［課題を解決するための手段］ 本発明の変倍レンズは、複数のレンズ群よりなってい
て、そのうち最も像側のレンズ群が負の屈折力を有する
もので、各レンズ群間の間隔を変化させることによって
変倍を行なうレンズ系で、この負のレンズ群は、負の屈
折力をもつレンズのみにて構成され２枚以上のレンズよ
りなり、この負のレンズ群中に少なくとも１枚の屈折率
分布型レンズを有するものである。[Means for Solving the Problems] The variable power lens according to the present invention comprises a plurality of lens groups, of which the lens group closest to the image has a negative refractive power. This negative lens group is composed of only two lenses having a negative refractive power, and is composed of two or more lenses. At least one lens is included in the negative lens group. It has a refractive index distribution type lens.
ここで負の屈折力をもつ屈折率分布型レンズとは、面
の屈折力と媒質の屈折力を含めた全体での屈折力が負で
あることを意味している。Here, the gradient index lens having a negative refractive power means that the total refractive power including the refractive power of the surface and the refractive power of the medium is negative.
前述のように、変倍レンズにおいては、各群独立して
色収差が補正されていることが好ましく、したがって、
各群は、少なくとも１枚の正レンズと少なくとも１枚の
負レンズを有する構成になっているのが一般的である。As described above, in the variable power lens, it is preferable that the chromatic aberration is corrected independently for each group.
Each group is generally configured to have at least one positive lens and at least one negative lens.
本発明のように、高変倍率で全長の短い変倍レンズの
場合、各レンズ群の屈折力をを非常に強くする必要があ
り、更に相反する符号の屈折力を有している場合は、そ
れだけ面の曲率半径が小さくなり、そのため収差の発生
量が大きく補正が出来なくなる。As in the present invention, in the case of a variable power lens having a high magnification and a short overall length, it is necessary to make the refractive power of each lens group extremely strong. As a result, the radius of curvature of the surface becomes smaller, so that the amount of occurrence of aberration becomes large and correction cannot be performed.
本発明の変倍レンズは、レンズ系の全長を非常に短く
するために、最も像側の負の屈折力をもったレンズ群を
負の屈折力を持つレンズのみにて構成した。更にこの負
の屈折力をもったレンズ群は、レンズ系の高変倍率にし
その全長を短くするため、広角端での軸外収差を補正す
るためとから、少なくとも２枚のレンズにて構成するこ
とが望ましい。しかし、この負の屈折力をもつレンズ群
は、正レンズを有していないために均質レンズのみでは
色収差を補正できない。そこで本発明では、このレンズ
群中に少なくとも１枚の屈折率分布型レンズを導入し
た。In order to make the overall length of the lens system extremely short, the variable power lens according to the present invention is configured such that the lens unit having the negative refractive power closest to the image side includes only the lens having the negative refractive power. Further, the lens unit having the negative refractive power is constituted by at least two lenses in order to increase the magnification of the lens system and shorten the overall length thereof, and to correct off-axis aberrations at the wide-angle end. It is desirable. However, since this lens group having a negative refractive power does not have a positive lens, chromatic aberration cannot be corrected only with a homogeneous lens. Therefore, in the present invention, at least one gradient index lens is introduced into this lens group.
本発明の変倍レンズで用いられる屈折率分布型レンズ
は、半径方向に屈折率分布を有するラジアル型であっ
て、次の式にて表わされる屈折率分布を有している。The gradient index lens used in the variable power lens of the present invention is a radial type having a refractive index distribution in a radial direction, and has a refractive index distribution represented by the following equation.
ｎ（ｒ）＝n0＋n1・r2＋n2・r4＋n3・r6＋… ここでn0はレンズの光軸上での屈折率、ｒは光軸から
半径方向の距離、ｎ（ｒ）は光軸から半径ｒの所での屈
折率、n1,n2,n3,…は夫々２次,4次,6次…の係数であ
る。n (r) = n 0 + n 1 · r 2 + n 2 · r 4 + n 3 · r 6 + ... where n 0 is the refractive index of the lens on the optical axis, r is the radial distance from the optical axis, and n (R) is a refractive index at a radius r from the optical axis, and n 1 , n 2 , n 3 ,... Are second-order, fourth-order, sixth-order coefficients, respectively.
上記のような、ラジアル型の屈折率分布型レンズによ
り軸上色収差を補正するための条件式は、次のように表
わされる。The conditional expression for correcting axial chromatic aberration by the radial type gradient index lens as described above is expressed as follows.
φs/ν0d＋φM/ν1d＝０ ここでφｓは面の屈折力、φＭは媒質の屈折力、ν0d
は光軸上の屈折率より求められるアッベ数、ν1dは屈折
率分布式の２次の係数n1より求まる値である。即ちφM,
ν0d,ν1dは夫々次の式で求められる値である。φ s / ν 0d + φ M / ν 1d = 0 where φ s is the refractive power of the surface, φ M is the refractive power of the medium, and ν 0d
Is the Abbe number obtained from the refractive index on the optical axis, and ν 1d is a value obtained from the secondary coefficient n 1 of the refractive index distribution equation. That is, φ M ,
ν 0d and ν 1d are values obtained by the following equations, respectively.
φＭ＝−2n1・Ｄ ν0d＝（n0d−１）／（n0F−n0C） ν1d＝n1d/（n1F−n1C） ただしn1は屈折率分布式の２次の係数、Ｄは屈折率分
布型レンズの光軸上の厚み、n0d,n0F,n0Cは夫々ｄ線,F
線,C線の光軸上の屈折率、n1d,n1F,n1Cは夫々ｄ線,F線,
C線の２次の係数である。 φ M = -2n 1 · D ν 0d = (n 0d -1) / (n 0F -n 0C) ν 1d = n 1d / (n 1F -n 1C) However n 1 is the second order refractive index distribution type Coefficient, D is the thickness of the gradient index lens on the optical axis, n 0d , n 0F , n 0C are the d-line and F, respectively.
, N 1d , n 1F , n 1C are the d-line, F-line,
This is the second order coefficient of the C line.
上記の色収差補正のための式から明らかなように、媒
質の屈折力φＭとν1dの値とを操作することによって軸
上色収差を均質レンズ系に比べて極めて小さい値や零又
は逆符号の値にすることが可能である。As is clear from the above equation for correcting chromatic aberration, the axial chromatic aberration can be reduced to a very small value or zero or reverse sign compared to the homogeneous lens system by manipulating the refractive power φ M and the value of ν 1d of the medium. It can be a value.
本発明のレンズ系は、上記のように屈折率分布型レン
ズの媒質が、均質レンズ系とは逆符号の軸上色収差を発
生させることが可能であることを利用して、均質レンズ
のみらなるレンズ系ではなし得なかったレンズ構成の変
倍レンズとしたものである。即ち、本発明の変倍レンズ
において、最も像側の負の屈折力をもったレンズ群は、
正の軸上色収差を発生させる構成要素がないために、必
ず大きな負の軸上色収差が発生する。これをこのレンズ
群に少なくとも１枚の屈折率分布型レンズを用いること
によって全体として負の屈折力をもったレンズでありな
がらその媒質で正の軸上色収差を発生させ互いに打ち消
し合うようにした。そのためには、次の条件（１）を満
足することが望ましい。The lens system of the present invention consists of only a homogeneous lens by utilizing the fact that the medium of the gradient index lens can generate axial chromatic aberration of the opposite sign to that of the homogeneous lens system as described above. This is a variable power lens having a lens configuration that cannot be achieved by a lens system. That is, in the variable power lens of the present invention, the lens group having the negative refractive power closest to the image side is:
Since there is no component that generates positive axial chromatic aberration, large negative axial chromatic aberration always occurs. By using at least one refractive index distribution type lens in this lens group, a positive axial chromatic aberration is generated in the medium while the lens has a negative refractive power as a whole so that the lenses cancel each other. For that purpose, it is desirable to satisfy the following condition (1).
（１） 1/｛（fW）２・n1d・ν1d｝＜０ ここでfWは広角端における全系の焦点距離、n1d・ν
1dは夫々前記の屈折率分布型レンズのｄ線の分布式の２
次の係数およびd,F,C線の屈折率分布式の２次の係数よ
り求められる値である。(1) 1 / ｛(f W ) 2 · n 1d · ν 1d ｝ <0 where f W is the focal length of the whole system at the wide-angle end, and n 1d · ν
1d is the d-line distribution equation 2 of the above-mentioned gradient index lens.
It is a value obtained from the following coefficient and the second-order coefficient of the d, F, C line refractive index distribution equation.
上記条件（１）の上限を越えると、屈折率分布型レン
ズの媒質で正の軸上収差を発生させることが出来なくな
り、全系での色収差を良好に補正することが出来ない。When the value exceeds the upper limit of the above condition (1), positive axial aberration cannot be generated in the medium of the gradient index lens, and chromatic aberration in the entire system cannot be satisfactorily corrected.
更に本発明にレンズ系は、全長を短くするために最も
像側の負の屈折率力を有するレンズ群の屈折力を強めた
ことにより、このレンズ群で発生する負の軸上色収差の
値がかなり大きなものになる。したがってこれを打ち消
すための屈折率分布型レンズの媒質で発生させる正の軸
上色収差を大きな値にする必要があり、そのためより効
果的に正の軸上収差を発生させるためには、次の条件
（２）を満足させなければならない。Further, in the present invention, the lens system has a lens unit having a negative refractive power closest to the image side, in order to shorten the overall length. By increasing the refractive power of the lens unit, the value of negative axial chromatic aberration generated in this lens unit is reduced. It will be quite large. Therefore, it is necessary to increase the positive axial chromatic aberration generated in the medium of the gradient index lens to cancel this, and to generate a positive axial aberration more effectively, the following conditions must be satisfied. (2) must be satisfied.
（２） ｜ν1d|＜50 この条件（２）の上限を越えると効果的に正の軸上色
収差を発生させることが出来なくなり、色収差を十分良
好に補正し得なくなる。(2) | ν 1d | <50 When the value exceeds the upper limit of the condition (2), positive axial chromatic aberration cannot be effectively generated, and chromatic aberration cannot be sufficiently sufficiently corrected.
また、本発明の変倍レンズにおいて、大きな変倍比を
得ることと全長を短くすることとを同時に達成するため
には、次の条件（３），（４）を満足することが望まし
い。In the variable power lens of the present invention, it is desirable to satisfy the following conditions (3) and (4) in order to simultaneously obtain a large zoom ratio and shorten the overall length.
（３） −0.40＜fn/fT＜−0.05 （４） 0.20＜BW/Z＜0.70 ただし、fnは最も像側の負のレンズ群の焦点距離、fT
は望遠端における全系の焦点距離、BWは広角端における
望遠比（全長／焦点距離）、Ｚは変倍比である。(3) −0.40 <f n / f T <−0.05 (4) 0.20 <B W /Z<0.70 where f n is the focal length of the negative lens group closest to the image side, f T
The focal length of the entire system at the telephoto end, B W telephoto ratio at the wide-angle end (total length / focal length), Z is a zoom ratio.
条件（３）においてfn/fTが下限の−0.40を越えると
最も像側の負のレンズ群の屈折力が弱くなりすぎ、レン
ズ系の全長を短くすることができなくなる。又上限の−
0.05を越えると最も像側の負のレンズ群の屈折力が強く
なりすぎてそこで発生する諸収差特に広角端での正の歪
曲収差を補正しきれなくなる。If f n / f T exceeds the lower limit of −0.40 in the condition (3), the refractive power of the negative lens unit closest to the image side becomes too weak, so that the total length of the lens system cannot be shortened. Also the upper limit-
If it exceeds 0.05, the refractive power of the negative lens unit closest to the image side becomes too strong, and it becomes impossible to correct various aberrations generated there, especially positive distortion at the wide-angle end.
上記条件（４）において、BW/Zが下限の0.20を越える
とレンズ系を小型にすることは出来るが、各レンズ群の
屈折力が強くなりすぎて収差の補正ができなくなる。又
上限の0.70を越えるとレンズ系を小型にすることが出来
なくなる。In the above condition (4), if B W / Z exceeds the lower limit of 0.20, the lens system can be made small. However, the refractive power of each lens unit becomes too strong, so that aberration cannot be corrected. If the upper limit of 0.70 is exceeded, the lens system cannot be reduced in size.
以上説明した本発明の変倍レンズにおいて、最も像側
の負の屈折力のレンズ群中に設けられた屈折率分布型レ
ンズを条件（１）の代わりに次の条件（１′）を満足す
るようにすれば一層良好に収差を補正し得るようにな
る。In the vari-focal lens of the present invention described above, the gradient index lens provided in the lens unit having the negative refractive power closest to the image side satisfies the following condition (1 ') instead of the condition (1). By doing so, the aberration can be corrected more favorably.
（１′） −20＜1/｛（fW）２・n1d・ν1d｝＜０ この条件の下限値の範囲内にすれば媒質による色収差
の補正を十分に行ない得る。(1 ′) − 20 <1 / ｛(f W ) 2 · n 1d · ν 1d ｝ <0 When the value falls within the lower limit of this condition, chromatic aberration due to the medium can be sufficiently corrected.
［実施例］ 次に本発明の高変倍率のコンパクトな変倍レンズの各
実施例について説明する。[Embodiments] Next, each embodiment of the compact zoom lens having a high zoom ratio of the present invention will be described.
本発明の実施例１は、第１図に示す通りのレンズ構成
で、正の屈折力を有する第１レンズ群(I)と、正の屈折
力を有する第２レンズ群(II)と、負の屈折力を有する第
３レンズ群(III)とより構成されている３群変倍レンズ
で、２群構成ではなし得なかった変倍比が約３の変倍レ
ンズである。更にレンズ系の全長を短くするために負の
第３レンズ群（最も像側の負のレンズ群）をそれぞれ負
の屈折力を有する３枚のレンズにて構成し、そのレンズ
群中の最も物体側のレンズを媒質が負の屈折力となる屈
折率分布型レンズにしてある。Example 1 of the present invention has a lens configuration as shown in FIG. 1 and has a first lens group (I) having a positive refractive power, a second lens group (II) having a positive refractive power, and a negative lens group. This is a three-unit variable power lens composed of a third lens group (III) having a refracting power of 3 and a variable power ratio of about 3, which cannot be achieved by the two-unit configuration. Further, in order to shorten the total length of the lens system, the negative third lens unit (the negative lens unit closest to the image side) is composed of three lenses each having a negative refractive power, and The lens on the side is a gradient index lens in which the medium has a negative refractive power.
この実施例のように最も像側のレンズ群の負の屈折力
を有するようなレンズ系では、広角端での正の歪曲収差
と望遠端での球面収差の発生が問題になる。特に、広角
端でレンズ系の全長を短くしようとすると正の歪曲収差
の発生が顕著になる。In a lens system having the negative refractive power of the lens unit closest to the image side as in this embodiment, the generation of positive distortion at the wide-angle end and spherical aberration at the telephoto end poses a problem. In particular, when the total length of the lens system is reduced at the wide-angle end, the occurrence of positive distortion becomes remarkable.
本実施例においては、媒質が負の屈折力になるような
屈折率分布型レンズを負の第３レンズ群中に用いること
によってレンズ面の曲率をゆるめ正の歪曲収差の発生を
防ぐと共に更にその媒質で負の歪曲収差を発生させて補
正している。In the present embodiment, the refractive index distribution type lens in which the medium has a negative refractive power is used in the negative third lens unit to loosen the curvature of the lens surface to prevent the occurrence of positive distortion and further reduce the curvature. Correction is made by generating negative distortion in the medium.
この歪曲収差を良好に補正するためには、次の条件を
満足することが望ましい。To satisfactorily correct this distortion, it is desirable to satisfy the following conditions.
（５） ０＜n1d・（fW）２＜15 ただしfWは広角端における全系の焦点距離である。(5) 0 <n 1d · (f W ) 2 <15 where f W is the focal length of the entire system at the wide-angle end.
この条件（５）の下限を越えると屈折率分布型レンズ
の媒質が正の屈折力を持つことになり、逆に負の面の屈
折力が強くなり、そこで発生する歪曲収差が補正できな
くなる。If the lower limit of the condition (5) is exceeded, the medium of the gradient index lens will have a positive refractive power, and conversely, the refractive power of the negative surface will become strong, and it will be impossible to correct the distortion generated there.
又屈折率分布型レンズを条件（１），（２）を満足す
る屈折率分布にすることによって、正の屈折力のレンズ
が存在しないにも拘わらず、屈折率分布型レンズの媒質
で正の軸上色収差を発生させ軸上色収差を良好に補正し
ている。By making the gradient index lens have a refractive index distribution that satisfies the conditions (1) and (2), a positive refractive index medium is used in the medium of the gradient index lens even though there is no lens having a positive refractive power. On-axis chromatic aberration is generated, and on-axis chromatic aberration is satisfactorily corrected.
またこの実施例は、正の第２レンズ群中の最も像側の
正レンズに媒質が正の屈折力になるような屈折率分布型
レンズを用いている。そしてこれによって面の曲率を緩
め、特に望遠端で顕著になる負の球面収差をその媒質で
正の球面収差を発生させて補正している。In this embodiment, a gradient index lens in which the medium has a positive refractive power is used as the positive lens closest to the image in the second positive lens unit. Thereby, the curvature of the surface is relaxed, and negative spherical aberration which is particularly conspicuous at the telephoto end is corrected by generating positive spherical aberration in the medium.
以上述べたように、この実施例１では、条件（１），
（２），（５）を満足する媒質が負の屈折力を有する屈
折率分布型レンズを、最も像側の負の第３レンズ群中に
用いることによって、変倍比が約３で、広角端における
望遠比が1.38と非常にコンパクトな変倍レンズが得られ
る。As described above, in the first embodiment, the conditions (1),
By using a gradient-index lens in which the medium satisfying the conditions (2) and (5) has a negative refractive power in the negative third lens unit closest to the image side, the zoom ratio is about 3, and the wide-angle lens is wide. A very compact zoom lens with a telephoto ratio at the end of 1.38 is obtained.
本発明の実施例２は、第２図に示すように物体側から
順に正の屈折力を有する第１レンズ群(I)と、正の屈折
力を有する第２レンズ群(II)と、負の屈折力を有する第
３レンズ群(III)とよりなる３群変倍レンズで、同様に
変倍比が約３のレンズ系である。In the second embodiment of the present invention, as shown in FIG. 2, a first lens group (I) having a positive refractive power, a second lens group (II) having a positive refractive power, This is a three-unit variable power lens system including a third lens unit (III) having a refractive power of 1. The lens system also has a zoom ratio of about 3.
この実施例２も実施例１と同様に負の屈折力を有する
第３レンズ群の最も物体側のレンズを、条件（１），
（２），（５）を満足する媒質が負の屈折力となる屈折
率分布型レンズにしてある。In the second embodiment, the lens closest to the object in the third lens group having a negative refractive power, as in the first embodiment, is set under the conditions (1) and (2).
The medium satisfying (2) and (5) is a gradient index lens having a negative refractive power.
特にこの実施例２では、負の屈折力を大部分をこの屈
折率分布型レンズの媒質に持たせることによって、その
レンズ面の曲率を緩め、面で発生する正の歪曲収差と負
の軸上色収差の発生量を最小限にし、負の第３レンズ群
を２枚のレンズにて構成している。In particular, in the second embodiment, by giving most of the negative refractive power to the medium of the gradient index lens, the curvature of the lens surface is relaxed, and the positive distortion generated on the surface and the negative on-axis The amount of chromatic aberration is minimized, and the negative third lens group is composed of two lenses.
またこの実施例２も望遠端での球面収差を補正するた
めに正の第２レンズ群中の最も像側の正レンズを媒質を
正の屈折力となる屈折率分布型レンズにしている。この
実施例も広角端の望遠比が1.38で非常にコンパクトであ
る。In the second embodiment as well, in order to correct the spherical aberration at the telephoto end, the positive lens closest to the image in the positive second lens group is a refractive index distribution type lens in which the medium has a positive refractive power. This embodiment is also very compact with a telephoto ratio of 1.38 at the wide-angle end.
実施例３は第３図に示す通りのレンズ構成で、物体側
から順に正の屈折力を有する第１レンズ群(I)と、正の
屈折力を有する第２レンズ群(II)と、正の屈折力を有す
る第３レンズ群(III)と、負の屈折力を有する第４レン
ズ群(IV)よりなる４群変倍レンズで、変倍比は約３であ
る。この実施例は、実施例２と同様に最も像側の負のレ
ンズ群（第４レンズ群）を２枚のレンズで構成してある
が、広角端での望遠比を更に小さくするための２枚のレ
ンズの両方を媒質に正の屈折力を持たせた屈折率分布型
レンズにしてある。Example 3 has a lens configuration as shown in FIG. 3, and includes, in order from the object side, a first lens group (I) having a positive refractive power, a second lens group (II) having a positive refractive power, a third lens group having a refractive power and (III), the fourth lens group (IV) 4 group zoom lens made of having a negative refractive power, a zoom ratio of about 3. In this embodiment, the negative lens unit (fourth lens unit) closest to the image side is composed of two lenses as in the second embodiment. However, the second lens unit is used to further reduce the telephoto ratio at the wide-angle end. Both of the lenses are gradient index lenses in which the medium has a positive refractive power.
広角端での望遠比を更に小さくした場合、特に広角端
で発生する正の歪曲収差と非点収差が大きくなる。歪曲
収差、非点収差を抑えるためには、レンズの形状を絞り
に対してコンセントリックにすることが望ましく、その
ため第４レンズ群の２枚のレンズの形状は、いずれも物
体側に凹面を向けた負のメニスカスレンズにしてある。
しかしこの場合でも面で発生する正の歪曲収差量は大き
く、均質レンズでは限界があり、屈折率分布型レンズに
より収差補正がなされている。本来ならば、負の第４レ
ンズ群に用いる屈折率分布型レンズは、媒質に負の屈折
力を持たせて面の曲率を緩くし、収差の発生量を押える
ようにする。しかしこの実施例のように少ないレンズ枚
数で強い屈折力を得ようとすると、媒質の屈折率差が大
きくなりすぎて実用状好ましくない。その上媒質が負の
屈折力になると面に形成された屈折率分布の補正項によ
って正の歪曲収差が発生するという悪循環になる。When the telephoto ratio at the wide-angle end is further reduced, positive distortion and astigmatism particularly occurring at the wide-angle end become large. In order to suppress distortion and astigmatism, it is desirable that the shape of the lens is concentric with respect to the stop. Therefore, the shape of each of the two lenses in the fourth lens group should be concave toward the object side. It has a negative meniscus lens.
However, even in this case, the amount of positive distortion generated on the surface is large, there is a limit in a homogeneous lens, and aberration is corrected by a gradient index lens. Originally, the refractive index distribution type lens used for the negative fourth lens group makes the medium have a negative refractive power to loosen the curvature of the surface and suppress the amount of aberration. However, if an attempt is made to obtain a strong refractive power with a small number of lenses as in this embodiment, the refractive index difference of the medium becomes too large, which is not preferable in practical use. In addition, when the medium has a negative refractive power, a vicious cycle occurs in which positive distortion occurs due to the correction term of the refractive index distribution formed on the surface.
この実施例３においては、第４レンズ群の負の屈折力
を面に負担させ、更にその面を絞りに対しコンセントリ
ックな形状にして非点収差、正の歪曲収差の発生を小さ
くしている。しかしそれでも正の歪曲収差は補正しきれ
ず、屈折率分布型レンズを導入して、その媒質を正の屈
折力になるような分布にし、面に形成された屈折率分布
の補正項で負の歪曲収差を発生させて収差を良好に補正
している。In the third embodiment, the negative refractive power of the fourth lens group is applied to the surface, and the surface is made concentric with respect to the stop to reduce the occurrence of astigmatism and positive distortion. . However, the positive distortion could not be corrected yet, and a gradient index lens was introduced to make the medium a distribution with a positive refractive power, and negative distortion was corrected by the correction term of the refractive index distribution formed on the surface. The aberration is generated and the aberration is satisfactorily corrected.
この屈折率分布型レンズは、条件（１），（２）を満
足し、その媒質で正の軸上色収差を発生させて軸上色収
差の補正を行なっている。更にこの実施例３は、正の第
３レンズ群の最も像側の正レンズに光軸から離れるにし
たがって正の屈折力が弱くなるような非球面を用いるこ
とによって、特に負の方向に発生しがちになる望遠端で
の球面収差を補正している。The refractive index distribution type lens satisfies the conditions (1) and (2), and corrects axial chromatic aberration by generating positive axial chromatic aberration in the medium. Further, in the third embodiment, the use of an aspheric surface whose positive refractive power becomes weaker as the distance from the optical axis increases as the distance from the optical axis increases, particularly in the negative direction, as the positive lens closest to the image in the third positive lens unit. Spherical aberration at the telephoto end, which tends to occur, is corrected.
この実施例３は、以上のようにして変倍比が約３であ
りながら広角端での望遠比が1.24と非常にコンパクトな
変倍レンズになっている。As described above, Embodiment 3 is a very compact zoom lens having a telephoto ratio of 1.24 at the wide-angle end while having a zoom ratio of about 3.
実施例４は、第４図に示すレンズ構成の変倍レンズで
ある。即ち物体側から順に正の屈折力を有する第１レン
ズ群(I)と、正の屈折力を有する第２レンズ群(II)と、
正の屈折力を有する第３レンズ群(III)と、負の屈折力
を有する第４レンズ群(IV)とよりなる４群変倍レンズ
で、変倍比は約３である。この実施例の広角端での望遠
比は実施例３の変倍レンズとほぼ同じの1.23であるが望
遠端での望遠比が更に小になっており、実施例３が0.84
であるのに対し、この実施例のレンズ系では0.79であ
る。又屈折率分布型レンズは１枚のみ用いられている。
また実施例３と同様に負の屈折力の第４レンズ群の各レ
ンズは物体側に凹面を向けた負のメニスカスレンズの形
状であって、ここで用いている屈折率分布型レンズの媒
質は正の屈折力を持っている。この屈折率分布型レンズ
の作用は、実施例３で用いられているものと同様である
が、１枚減少した分だけ正の歪曲収差の負の軸上色収差
の補正能力を強めるために媒質の屈折力を強くしなけれ
ばならない。以上の理由から次の条件（６）を満足する
ことが望ましい。Example 4 is a variable power lens having the lens configuration shown in FIG. That is, a first lens group (I) having a positive refractive power and a second lens group (II) having a positive refractive power in order from the object side,
This is a four-unit zoom lens composed of a third lens group (III) having a positive refractive power and a fourth lens group (IV) having a negative refractive power, and has a zoom ratio of about 3. The telephoto ratio at the wide-angle end in this embodiment is 1.23, which is almost the same as that of the variable power lens of the third embodiment, but the telephoto ratio at the telephoto end is even smaller.
Is 0.79 in the lens system of this embodiment. Further, only one refractive index distribution type lens is used.
Similarly to the third embodiment, each lens of the fourth lens group having a negative refractive power has the shape of a negative meniscus lens having a concave surface facing the object side. The medium of the gradient index lens used here is Has positive refractive power. The function of the gradient index lens element is the same as that used in the third embodiment. However, in order to enhance the ability to correct the negative axial chromatic aberration of the positive distortion by the decrease of one lens, The refractive power must be increased. For the above reasons, it is desirable to satisfy the following condition (6).
（６） −15＜n1d・（fW）２＜０ この条件（６）の下限を越えると、屈折率分布型レン
ズの正の媒質が強くなりすぎて所望の屈折力を得るため
には面の曲率が強くならざるを得ず、その面で発生する
諸収差を補正することが困難になる。また上限を越える
と屈折率分布型レンズの媒質が負の屈折力を持つことに
なり、実施例３の説明で述べたように特に正の歪曲収差
を補正出来なくなる。(6) −15 <n 1d · (f W ) 2 <0 If the lower limit of the condition (6) is exceeded, the positive medium of the gradient index lens becomes too strong to obtain a desired refractive power. The curvature of the surface must be increased, and it becomes difficult to correct various aberrations generated on the surface. If the upper limit is exceeded, the medium of the gradient index lens will have a negative refractive power, and it will be impossible to correct particularly positive distortion as described in the description of the third embodiment.
更に負の第４レンズ群中のどのレンズを屈折率分布型
レンズにしても諸収差の補正は可能であるが、特に第４
レンズ群中の最も物体側のレンズを屈折率分布型レンズ
にすると効果的である。それは、変倍比が大きいことか
ら、望遠端での球面収差や軸上色収差の変化量が大きく
なり、負の第４レンズ群の最も物体側のレンズが望遠端
でのマージナル光線の光線高が最も高くなるからであ
る。Further, although any lens in the negative fourth lens group may be made a gradient index lens, various aberrations can be corrected.
It is effective if the lens closest to the object in the lens group is a gradient index lens. That is, since the zoom ratio is large, the amount of change in spherical aberration and axial chromatic aberration at the telephoto end increases, and the height of the marginal ray at the telephoto end is reduced when the lens closest to the object in the negative fourth lens group is at the telephoto end. Because it becomes the highest.
又この実施例においても、実施例３と同様に正の第３
レンズ群の最も像側の正レンズに光軸から離れるように
したがって正の屈折力が弱くなるような非球面を用いる
ことによって、特に負の方向に発生しがちな望遠端にお
ける球面収差を補正している。Also, in this embodiment, the positive third
By using an aspherical surface for the positive lens closest to the image side of the lens group, the positive refractive power of which decreases as the distance from the optical axis increases, the spherical aberration particularly at the telephoto end, which tends to occur in the negative direction, is corrected. ing.
以上述べたように、実施例４は、条件（１），
（２），（６）を満足する屈折率分布型レンズを負の第
４レンズ群に少なくとも１枚用いることによって変倍比
が約３で、広角端，望遠端での望遠比が夫々1.23,0.79
と非常にコンパクトな変倍レンズになし得たものであ
る。As described above, the fourth embodiment satisfies the condition (1),
By using at least one gradient index lens satisfying (2) and (6) in the negative fourth lens group, the zoom ratio is about 3, and the telephoto ratio at the wide-angle end and the telephoto end is 1.23, respectively. 0.79
And a very compact zoom lens.
実施例５は、第５図に示すように物体側から順に正の
屈折力を有する第１レンズ群(I)と、正の屈折力を有す
る第２レンズ群(II)と、負の屈折力を有する第３レンズ
群(III)よりなる変倍比が約３の３群変倍レンズであ
る。In Example 5, as shown in FIG. 5, a first lens group (I) having a positive refractive power, a second lens group (II) having a positive refractive power, and a negative refractive power in order from the object side. The third lens group (III) having a zoom ratio of about 3.
この実施例５も、実施例４と同様に、条件（１），
（２），（６）を満足する屈折率分布型レンズを少なく
とも１枚最も像側に配置された負のレンズ群（第３レン
ズ群）中に設け、これによってレンズ系の小型化を図っ
たもので、広角端の望遠比が1.16である。上記の第３レ
ンズ群中に設けた屈折率分布型レンズの作用は、実施例
３と同様である。In Example 5, as in Example 4, conditions (1) and
At least one gradient index lens satisfying the conditions (2) and (6) is provided in the negative lens group (third lens group) arranged closest to the image side, thereby miniaturizing the lens system. The telephoto ratio at the wide-angle end is 1.16. The function of the gradient index lens provided in the third lens group is the same as that of the third embodiment.
更にこの実施例のレンズ系は、正の第２レンズ群の最
も像側の正レンズを媒質が負の屈折力になるような分布
を有する屈折率分布型レンズを用いている。そしてこの
屈折率分布型レンズの媒質で広角端から望遠端にかけて
のコマ収差と、負の方向に発生しがちな望遠端での球面
収差を補正している。Further, in the lens system of this embodiment, a refractive index distribution type lens having a distribution such that the medium has a negative refractive power is used for the positive lens closest to the image in the positive second lens group. The medium of the refractive index distributed lens corrects coma from the wide-angle end to the telephoto end and spherical aberration at the telephoto end, which tends to occur in the negative direction.
またこの実施例において、正の第１レンズ群に光軸か
ら離れるにしたがって正の屈折力が弱くなるような非球
面を用いれば、望遠端での球面収差を一層良好に補正す
ることが出来る。Further, in this embodiment, if an aspherical surface is used in which the positive refractive power becomes weaker as the distance from the optical axis increases, the spherical aberration at the telephoto end can be more favorably corrected.
以上述べたように、この実施例５は、３群構成であり
ながら広角端での望遠比が1.16という超小型の変倍レン
ズである。As described above, the fifth embodiment is an ultra-small variable power lens having a telephoto ratio of 1.16 at the wide-angle end while having a three-group configuration.
次に本発明の各実施例のデーターを示す。 Next, data of each embodiment of the present invention will be shown.
実施例１ ｆ＝36.2〜101.15mm、F/4.65〜F/6.73 r1＝71.2967 d1＝1.1011 n01＝1.83481 ν01＝42.72 r2＝17.2869 d2＝3.2000 n02＝1.69680 ν02＝56.49 r3＝56.6539 d3＝0.6725 r4＝17.6783 d4＝3.0230 n03＝1.61700 ν03＝62.79 r5＝41.2464 d5＝D1（可変） r6＝−18.0245 d6＝1.1242 n04＝1.77250 ν04＝49.66 r7＝−64.6503 d7＝0.1629 r8＝24.8362 d8＝1.3483 n05＝1.84666 ν05＝23.78 r9＝32.7567 d9＝0.9273 r10＝∞（絞り） d10＝1.5166 r11＝22.2987 d11＝2.3850 n06＝1.56016 ν06＝60.30 r12＝−29.7301（非球面） d12＝0.7199 r13＝−19.9710 d13＝4.1185n07（屈折率分布型レンズ１） r14＝−14.5467 d14＝D2（可変） r15＝−49.6669 d15＝2.9985n08（屈折率分布型レンズ２） r16＝−60.3853 d16＝4.4609 r17＝−11.8362 d17＝1.6798 n09＝1.77250 ν09＝49.66 r18＝−30.1955 d18＝1.0251 r19＝−81.7818 d19＝2.4334 n010＝1.74100 ν010＝52.68 r20＝−686.9222 非球面係数 Ｅ＝0.31483×10-6、Ｆ＝−0.10516×10-6 Ｇ＝0.25200×10-8 ｆ 36.2 60.5 101.15 D1 2.806 11.756 15.823 D2 7.298 3.718 1.200 屈折率分布型レンズ１（n07） n0 n1 ｄ線 1.77250 −0.41885×10-3 Ｃ線 1.76780 −0.44378×10-3 Ｆ線 1.78337 −0.36069×10-3 n2 n3 ｄ線 0.19680×10-4 0.71278×10-7 Ｃ線 0.19650×10-4 0.69091×10-7 Ｆ線 0.19749×10-4 0.76381×10-7 屈折率分布型レンズ２（n0s） n0 n1 ｄ線 1.78471 0.17114×10-2 Ｃ線 1.77596 0.17416×10-2 Ｆ線 1.80648 0.16409×10-2 n2 n3 ｄ線 −0.18026×10-4 0.11881×10-7 Ｃ線 −0.18377×10-4 0.15564×10-7 Ｆ線 −0.17208×10-4 0.32878×10-8 1/｛（fW）２・n1d・ν1d｝＝−2.6233×10-2 ｜ν1d|＝16.997、fn/fT＝−0.1550 Bw/Z＝0.4943、n1d・（fW）２＝22427 実施例２ ｆ＝36.2〜101.14mm、F/4.65〜F/6.73 r1＝48.7977 d1＝1.3643 n01＝1.83481 ν01＝42.72 r2＝18.1719 d2＝3.4000 n02＝1.65160 ν02＝58.52 r3＝49.7203 d3＝0.1612 r4＝18.3552 d4＝3.0325 n03＝1.56873 ν03＝63.16 r5＝49.0742 d5＝D1（可変） r6＝−21.1415 d6＝1.0043 n04＝1.77250 ν04＝49.66 r7＝−135.7722 d7＝0.7149 r8＝43.2708 d8＝1.2000 n05＝1.84666 ν05＝23.78 r9＝274.2955 d9＝0.7877 r10＝∞（絞り） d10＝1.6827 r11＝45.9782 d11＝2.0003 n06＝1.56016 ν06＝60.30 r12＝−27.8406（非球面） d12＝0.7085 r13＝−18.0613 d13＝4.5446n07（屈折率分布型レンズ１） r14＝−14.4703 d14＝D2（可変） r15＝−219.7265 d15＝3.1676n08（屈折率分布型レンズ２） r16＝−339.1042 d16＝4.6823 r17＝−12.8823 d17＝1.8007 n09＝1.77250 ν09＝49.66 r18＝−40.5586 非球面係数 Ｅ＝0.63614×10-4、Ｆ＝−0.57094×10-6 Ｇ＝−0.4557×10-8、Ｈ＝0.40901×10-10 ｆ 36.2 60.5 101.14 D1 2.806 13.521 17.534 D2 9.943 4.871 1.200 屈折率分布型レンズ１（n07） n0 n1 ｄ線 1.77250 −0.24592×10-3 Ｃ線 1.76780 −0.28425×10-3 Ｆ線 1.78336 −0.15649×10-3 n2 n3 ｄ線 0.42195×10-5 −0.62409×10-8 Ｃ線 0.42311×10-5 −0.71455×10-8 Ｆ線 0.41925×10-5 −0.41301×10-8 屈折率分布型レンズ２（n08） n0 n1 ｄ線 1.78472 0.16482×10-2 Ｃ線 1.77596 0.16881×10-2 Ｆ線 1.80649 0.15551×10-2 n2 n3 ｄ線 −0.95660×10-5 −0.15590×10-7 Ｃ線 −0.96870×10-5 −0.15053×10-7 Ｆ線 −0.92837×10-5 −0.16842×10-7 1/｛（fW）２・n1d・ν1d｝＝−3.7356×10-2 ｜ν1d|＝12.395、fn/fT＝−0.1829 Bw/Z＝0.4944、n1d・（fW）２＝2.1597 実施例３ ｆ＝36.2〜101.15mm、F/4.65〜F/6.73 r1＝50.5219 d1＝1.0763 n01＝1.83481 ν01＝42.72 r2＝19.5967 d2＝2.5678 n02＝1.69680 ν02＝55.52 r3＝50.6890 d3＝0.1200 r4＝14.7278 d4＝2.5002 n03＝1.61700 ν03＝62.79 r5＝30.3624 d5＝D1（可変） r6＝−19.7109 d6＝1.3591 n04＝1.76200 ν04＝40.10 r7＝297.8886 d7＝0.1500 r8＝29.5656 d8＝3.5728 n05＝1.65160 ν05＝58.52 r9＝−21.2386 d9＝D2（可変） r10＝∞（絞り） d10＝1.5728 r11＝−15.3925 d11＝1.7490 n06＝1.76200 ν06＝40.10 r12＝−35.6443 d12＝0.8757 r13＝51.8051 d13＝3.6074 n07＝1.61700 ν06＝62.79 r14＝−17.8806（非球面） d14＝D3（可変） r15＝−21.0167 d15＝1.0001 n08（屈折率分布型レンズ１） r16＝−168.1433 d16＝3.8000 r17＝−12.2088 d17＝1.0001 n09（屈折率分布型レンズ２） r18＝−21.9543 非球面係数 Ｅ＝0.66132×10-4、Ｆ＝−0.41992×10-6 Ｇ＝−0.62935×10-8 ｆ 36.2 60.5 101.15 D1 2.400 5.537 8.567 D2 0.201 1.868 2.894 D3 10.444 5.068 1.250 屈折率分布型レンズ１（n08） n0 n1 ｄ線 1.74100 −0.41486×10-3 Ｃ線 1.73673 −0.31495×10-3 Ｆ線 1.75080 −0.64798×10-3 n2 n3 ｄ線 −0.52540×10-5 0.12416×10-7 Ｃ線 −0.71599×10-5 0.23638×10-7 Ｆ線 −0.80700×10-6 −0.13768×10-7 屈折率分布型レンズ２（n09） n0 n1 ｄ線 1.69680 −0.42632×10-3 Ｃ線 1.69297 −0.41913×10-3 Ｆ線 1.70552 −0.44309×10-3 n2 n3 ｄ線 −0.49684×10-5 0.28384×10-7 Ｃ線 −0.52769×10-5 0.30977×10-7 Ｆ線 −0.42485×10-5 0.22333×10-7 1/｛（fW）２・n1d・ν1d｝ ＝−1.4767（屈折率分布型レンズ１） 1/｛（fW）２・n1d・ν1d｝ ＝−0.1006（屈折率分布型レンズ２） ｜ν1d|＝1.2457（屈折率分布型レンズ１） ｜ν1d|＝17.794（屈折率分布型レンズ２） fn/fT＝−0.1769、Bw/Z＝0.4448 n1d・（fW）２＝−0.5436（屈折率分布型レンズ１） n1d・（fW）２＝−0.5587（屈折率分布型レンズ２） 実施例４ ｆ＝36.2〜101.12mm、F/4.65〜F/6.73 r1＝44.8237 d1＝1.0763 n01＝1.83481 ν01＝42.72 r2＝13.8718 d2＝2.7803 n02＝1.69680 ν02＝55.52 r3＝39.5808 d3＝0.1200 r4＝14.9330 d4＝2.6000 n03＝1.61700 ν03＝62.79 r5＝53.0050 d5＝D1（可変） r6＝−21.7602 d6＝0.7633 n04＝1.77250 ν04＝49.66 r7＝49.2205 d7＝0.1500 r8＝19.9897 d8＝1.8119 n05＝1.84666 ν05＝23.78 r9＝19.4923 d9＝2.5538 n06＝1.61700 ν06＝62.79 r10＝−23.5190 d10＝∞（可変） r11＝∞（絞り） d11＝1.6286 r12＝−15.2394 d12＝1.4808 n07＝1.80610 ν07＝40.95 r13＝−63.3648 d13＝0.8359 r14＝27.3754 d14＝3.6414 n08＝1.60729 ν08＝59.38 r15＝−16.9288（非球面） d15＝D3（可変） r16＝−14.8390 d16＝1.1025n09（屈折率分布型レンズ） r17＝−40.8072 d17＝3.7060 r18＝−11.8238 r18＝1.1064 n010＝1.77250 ν010＝49.66 r19＝−28.6253 非球面係数 Ｅ＝0.10683×10-3、Ｆ＝0.83640×10-7 Ｇ＝0.30537×10-8 ｆ 36.2 60.5 101.12 D1 2.303 3.881 8.783 D2 0.201 2.421 2.940 D3 9.527 4.987 1.392 屈折率分布型レンズ n0 n1 ｄ線 1.69895 −0.24603×10-2 Ｃ線 1.69223 −0.22776×10-2 Ｆ線 1.71543 −0.28865×10-2 n2 n3 ｄ線 −0.15455×10-5 −0.57306×10-8 Ｃ線 −0.47227×10-5 0.17074×10-7 Ｆ線 0.58680×10-5 −0.58942×10-7 1/｛（fW）２・n1d・ν1d｝＝−7.6762×10-2 ｜ν1d|＝4.0408、fn/fT＝−0.1517 Bw/Z＝0.4390、n1d・（fW）２＝−3.2239 実施例５ ｆ＝36.2〜101.15mm、F/4.65〜F/6.73 r1＝75.8983 d1＝1.0763 n01＝1.83481 ν01＝42.72 r2＝15.3667 d2＝3.0209 n02＝1.69680 ν02＝56.49 r3＝44.2457 d3＝0.1200 r4＝12.9571（非球面） d4＝2.6237 n03＝1.61700 ν03＝62.79 r5＝49.7031 d5＝D1（可変） r6＝−19.2240 d6＝0.8010 n04＝1.77250 ν04＝49.66 r7＝97.2859 d7＝0.2045 r8＝25.0180 d8＝1.2000 n05＝1.84666 ν05＝23.78 r9＝21.9566 d9＝0.1200 r10＝14.5899 d10＝1.8000 n06＝1.56384 ν06＝60.69 r11＝−47.5697 d11＝0.4372 r12＝∞（絞り） d12＝1.2928 r13＝−63.4292 d13＝1.2000 n07＝1.80610 ν07＝40.95 r14＝−46.5385 d14＝0.7321 r15＝141.8156 d15＝2.8604 n08（屈折率分布型レンズ１） r16＝−23.9114 d16＝D2（可変） r17＝−13.6068 d17＝1.2521 n09（屈折率分布型レンズ２） r18＝−50.9149 d18＝4.0284 r19＝−11.5646 d19＝1.2522 n010＝1.77250 ν010＝49.66 r20＝−20.6898 非球面係数 Ｅ＝−0.11836×10-4、Ｆ＝0.13779×10-7 Ｇ＝−0.68096×10-9 ｆ 36.2 60.5 101.15 D1 2.371 8.215 11.349 D2 8.608 4.106 1.001 屈折率分布型レンズ（n08） n0 n1 ｄ線 1.60311 0.27450×10-4 Ｃ線 1.60008 0.27547×10-4 Ｆ線 1.61002 0.27224×10-4 n2 n3 ｄ線 0.26422×10-4 0.61383×10-6 Ｃ線 0.25920×10-4 0.60210×10-6 Ｆ線 0.27593×10-4 0.64121×10-6 屈折率分布型レンズ２（n09） n0 n1 ｄ線 1.69680 −0.15538×10-2 Ｃ線 1.69297 −0.14799×10-2 Ｆ線 1.70552 −0.17262×10-2 n2 n3 ｄ線 −0.10118×10-4 0.31305×10-7 Ｃ線 −0.10798×10-4 0.33331×10-7 Ｆ線 −0.85303×10-5 0.26578×10-7 1/｛（fW）２・n1d・ν1d｝＝−7.7862×10-2 ｜ν1d|＝6.3077、fn/fT＝−0.1531 Bw/Z＝0.4152、n1d・（fW）２＝−2.0361 上記データーにおいて、r1,r2,…はレンズ各面の曲率
半径、d1,d2,…は各レンズの肉厚およびレンズ間隔、n
01,n02,…は各レンズの屈折率、ν01,ν02,…は各レン
ズのアッベ数である。Example 1 f = 36.2 to 101.15 mm, F / 4.65 to F / 6.73 r 1 = 71.2967 d 1 = 1.1101 n 01 = 1.83481 ν 01 = 42.72 r 2 = 17.2869 d 2 = 3.2000 n 02 = 1.69680 ν 02 = 56.49 r 3 = 56.6539 d 3 = 0.6725 r 4 = 17.6783 d 4 = 3.0230 n 03 = 1.61700 ν 03 = 62.79 r 5 = 41.2464 d 5 = D 1 (variable) r 6 = -18.0245 d 6 = 1.1242 n 04 = 1.77250 ν 04 = 49.66 r 7 = −64.6503 d 7 = 0.1629 r 8 = 24.8362 d 8 = 1.3483 n 05 = 1.84666 ν 05 = 23.78 r 9 = 32.7567 d 9 = 0.9273 r 10 = ∞ (aperture) d 10 = 1.5166 r 11 = 22.2987 d 11 = 2.3850 n 06 = 1.56016 ν 06 = 60.30 r 12 = −29.7301 (aspherical surface) d 12 = 0.7199 r 13 = −19.9710 d 13 = 4.1185n 07 (index distribution type lens 1) r 14 = −14.5467 d 14 = D 2 (variable) r 15 = −49.6669 d 15 = 2.9985n 08 (index distribution lens 2) r 16 = −60.3853 d 16 = 4.4609 r 17 = −11.8362 d 17 = 1.6798 n 09 = 1.77250 ν 09 = 49.66 r 18 = -30.1955 d 18 = 1.0251 r 19 = -81.7818 d 19 = 2.4334 n 01 0 = 1.74100 ν 010 = 52.68 r 20 = −686.9222 Aspherical surface coefficient E = 0.31483 × 10 −6 , F = −0.10516 × 10 −6 G = 0.25200 × 10 −8 f 36.2 60.5 101.15 D 1 2.806 11.756 15.823 D 2 7.298 3.718 1.200 Refractive index distributed lens 1 (n 07 ) n 0 n 1 d line 1.77250 −0.41885 × 10 -3 C line 1.76780 −0.44378 × 10 -3 F line 1.78337 −0.36069 × 10 -3 n 2 n 3 d line 0.19680 × 10 -4 0.71278 × 10 -7 C line 0.19650 × 10 -4 0.69091 × 10 -7 F line 0.19749 × 10 -4 0.76381 × 10 -7 Refractive index distributed lens 2 (n 0s ) n 0 n 1 d line 1.78471 0.17114 × 10 -2 C line 1.77596 0.17416 × 10 -2 F line 1.80648 0.16409 × 10 -2 n 2 n 3 d line -0.18026 × 10 -4 0.11881 × 10 -7 C line -0.18377 × 10 -4 0.15564 × 10 - 7 F line −0.17208 × 10 −4 0.32878 × 10 −8 1 / ｛(f W ) 2 · n 1d · ν 1d ｝ = − 2.6233 × 10 −2 | ν 1d | = 16.997, f n / f T = − 0.1550 B w /Z=0.4943, n 1d · (f W ) 2 = 22427 Example 2 f = 36.2 to 101.14 mm, F / 4.65 to F / 6.73 r 1 = 48.7977 d 1 = 1.3643 n 01 = 1.83481 ν 01 = 42.72 r 2 = 18.1719 d 2 = 3.4000 n 02 = 1.65160 ν 02 = 58.52 r 3 = 49.7203 d 3 = 0.1612 r 4 = 18.3552 d 4 = 3.0325 n 03 = 1.56873 ν 03 = 63.16 r 5 = 49.0742 d 5 = D 1 ( Variable) r 6 = -21.1415 d 6 = 1.0043 n 04 = 1.77250 v 04 = 49.66 r 7 = -135.7722 d 7 = 0.7149 r 8 = 43.2708 d 8 = 1.2000 n 05 = 1.84666 v 05 = 23.78 r 9 = 274.2955 d 9 = 0.7877 r 10 = ∞ (stop) d 10 = 1.6827 r 11 = 45.9782 d 11 = 2.0003 n 06 = 1.56016 ν 06 = 60.30 r 12 = -27.8406 ( aspherical) d 12 = 0.7085 r 13 = -18.0613 d 13 = 4.5446n 07 (Refractive index lens 1) r 14 = -14.4703 d 14 = D 2 (variable) r 15 = -219.7265 d 15 = 3.1676n 08 (Refractive index lens 2) r 16 = -339.1042 d 16 = 4.6823 r 17 = -12.8823 d 17 = 1.8007 n 09 = 1.77250 ν 09 = 49.66 r 18 = -40.5586 aspherical coefficient E = 0.63614 × 10 -4, F = -0.57094 × 10 -6 G = -0.4557 × 10 - 8 , H = 0.40901 × 10 -10 f 36.2 60.5 101.14 D 1 2.806 13.521 17.534 D 2 9 .943 4.871 1.200 Graded index lens 1 (n 07 ) n 0 n 1 d line 1.77250 −0.24592 × 10 -3 C line 1.76780 −0.28425 × 10 -3 F line 1.78336 −0.15649 × 10 -3 n 2 n 3 d Line 0.42195 × 10 -5 −0.62409 × 10 -8 C line 0.42311 × 10 -5 −0.71455 × 10 -8 F line 0.41925 × 10 -5 −0.41301 × 10 -8 Refractive index distributed lens 2 (n 08 ) n 0 n 1 d line 1.78472 0.16482 × 10 -2 C line 1.77596 0.16881 × 10 -2 F line 1.80649 0.15551 × 10 -2 n 2 n 3 d line −0.95660 × 10 -5 −0.15590 × 10 -7 C line −0.96870 × 10 -5 −0.15053 × 10 -7 F line −0.92837 × 10 -5 −0.16842 × 10 -7 1 / ｛(f W ) 2 · n 1d · ν 1d ｝ = − 3.7356 × 10 -2 | ν 1d | = 12.395 , F n / f T = −0.1829 B w /Z=0.4944, n 1d · (f W ) 2 = 2.1597 Example 3 f = 36.2 to 101.15 mm, F / 4.65 to F / 6.73 r 1 = 50.5219 d 1 = 1.0763 n 01 = 1.83481 ν 01 = 42.72 r 2 = 19.55967 d 2 = 2.5678 n 02 = 1.69680 ν 02 = 55.52 r 3 = 50.6890 d 3 = 0.1200 r 4 = 14.7278 d 4 = 2.5002 n 03 = 1.61700 ν 03 = 62.79 r 5 = 30.3624 d 5 = D 1 (variable) r 6 = -19.7109 d 6 = 1.3591 n 04 = 1.76200 ν 04 = 40.10 r 7 = 297.8886 d 7 = 0.1500 r 8 = 29.5656 d 8 = 3.5728 n 05 = 1.65160 ν 05 = 58.52 r 9 = -21.2386 d 9 = D 2 (variable) r 10 = ∞ (stop) d 10 = 1.5728 r 11 = -15.3925 d 11 = 1.7490 n 06 = 1.76200 ν 06 = 40.10 r 12 = -35.6443 d 12 = 0.8757 r 13 = 51.8051 d 13 = 3.6074 n 07 = 1.61700 ν 06 = 62.79 r 14 = -17.8806 ( aspherical) d 14 = D 3 (variable) r 15 = -21.0167 d 15 = 1.0001 n 08 ( gradient index lens 1) r 16 = −168.1433 d 16 = 3.8000 r 17 = −12.2088 d 17 = 1.0001 n 09 (index distribution lens 2) r 18 = −21.9543 aspheric coefficient E = 0.66132 × 10 −4 , F = −0.41992 × 10 -6 G = −0.62935 × 10 -8 f 36.2 60.5 101.15 D 1 2.400 5.537 8.567 D 2 0.201 1.868 2.894 D 3 10.444 5.068 1.250 Distributed index lens 1 (n 08 ) n 0 n 1 d-line 1.74100 −0.41486 × 10 -3 C line 1.73673 -0.31495 × 10 -3 F line 1.75080 -0.64798 × 10 -3 n 2 n 3 d line −0.52540 × 10 -5 0.12416 × 10 -7 C line −0.71599 × 10 -5 0.23638 × 10 -7 F line −0.80700 × 10 -6 −0.13768 × 10 -7 Distributed lens 2 (n 09 ) n 0 n 1 d line 1.69680 −0.42632 × 10 -3 C line 1.69297 −0.41913 × 10 -3 F line 1.70552 −0.44309 × 10 -3 n 2 n 3 d line −0.49684 × 10 − 5 0.28384 × 10 -7 C line −0.52769 × 10 -5 0.30977 × 10 -7 F line −0.42485 × 10 -5 0.22333 × 10 -7 1 / ｛(f W ) 2・ n 1d・ ν 1d ＝ ＝ −1.4767 (Distributed refractive index lens 1) 1 / ｛(f W ) 2 · n 1d · ν 1d ＝= − 0.1006 (Distributed refractive index lens 2) | ν 1d | = 1.2457 (Distributed refractive index lens 1) | ν 1d | = 17.794 (gradient index lens 2) f n / f T = -0.1769, B w /Z=0.4448 n 1d · (f W) 2 = -0.5436 ( gradient index lens 1) n 1d · ( f W ) 2 = −0.5587 (refractive index type lens 2) Example 4 f = 36.2 to 101.12 mm, F / 4.65 to F / 6.73 r 1 = 44.8237 d 1 = 1.0763 n 01 = 1.83481 ν 01 = 42.72 r 2 = 13.8718 d 2 = 2.7803 n 02 = 1.69680 ν 02 = 55.52 r 3 = 39.5808 d 3 = 0.1200 r 4 = 14.9330 d 4 = 2.6000 n 03 = 1.61700 ν 03 = 62.79 r 5 = 53.0050 d 5 = D 1 ( variable ) R 6 = -21.7602 d 6 = 0.7633 n 04 = 1.77250 v 04 = 49.66 r 7 = 49.2205 d 7 = 0.1500 r 8 = 19.9897 d 8 = 1.8 119 n 05 = 1.84666 v 05 = 23.78 r 9 = 19.4923 d 9 = 2.5538 n 06 = 1.61700 ν 06 = 62.79 r 10 = −23.5190 d 10 = ∞ (variable) r 11 = ∞ (aperture) d 11 = 1.6286 r 12 = -15.2394 d 12 = 1.4808 n 07 = 1.80610 ν 07 = 40.95 r 13 = -63.3648 d 13 = 0.8359 r 14 = 27.3754 d 14 = 3.6414 n 08 = 1.60729 ν 08 = 59.38 r 15 = -16.9288 ( aspherical) d 15 = D 3 (variable) r 16 = -14.8390 d 16 = 1.1025n 09 (Refractive index distributed lens) r 17 = -40.8072 d 17 = 3.7060 r 18 = -11.8238 r 18 = 1.1064 n 010 = 1.77 250 ν 010 = 49.66 r 19 = -28.6253 Aspheric coefficient E = 0.10683 × 10 -3 , F = 0.83640 × 10 -7 G = 0.30537 × 10 -8 f 36.2 60.5 101.12 D 1 2 .303 3.881 8.783 D 2 0.201 2.421 2.940 D 3 9.527 4.987 1.392 Refractive index distributed lens n 0 n 1 d line 1.69895 −0.24603 × 10 -2 C line 1.69223 −0.22776 × 10 -2 F line 1.71543 −0.28865 × 10 -2 n 2 n 3 d line −0.15455 × 10 -5 −0.57306 × 10 -8 C line −0.47227 × 10 -5 0.17074 × 10 -7 F line 0.58680 × 10 -5 −0.58942 × 10 -7 1 / ｛(f W ) 2 · n 1d · ν 1d ｝ = − 7.6762 × 10 −2 | ν 1d | = 4.0408, f n / f T = −0.1517 B w /Z=0.4390, n 1d · (f W ) 2 = −3.2239 Example 5 f = 36.2 to 101.15 mm, F / 4.65 to F / 6.73 r 1 = 75.8983 d 1 = 1.0763 n 01 = 1.83481 ν 01 = 42.72 r 2 = 15.3667 d 2 = 3.0209 n 02 = 1.69680 ν 02 = 56.49 r 3 = 44.2457 d 3 = 0.1200 r 4 = 12.9571 (aspherical surface) d 4 = 2.6237 n 03 = 1.61700 ν 03 = 62.79 r 5 = 49.7031 d 5 = D 1 (variable) r 6 = -19.2240 d 6 = 0.8010 n 04 = 1.77250 ν 04 = 49.66 r 7 = 97.2859 d 7 = 0.2045 r 8 = 25.0180 d 8 = 1.2000 n 05 = 1.84666 ν 05 = 23.78 r 9 = 21.9566 d 9 = 0.1200 r 10 = 14.5899 d 10 = 1.8000 n 06 = 1.56384 ν 06 = 60.69 r 11 = -47.5697 d 11 = 0.4372 r 12 = ∞ ( stop) d 12 = 1.2928 r 13 = -63.4292 d 13 = 1.2000 n 07 = 1.80610 ν 07 = 40.95 r 14 = -46.5385 d 14 = 0.7321 r 15 = 141.8156 d 15 = 2.8604 n 08 ( gradient index lens 1) r 16 = -23.9114 d 16 = D 2 ( variable) r 17 = -13.6068 d 17 = 1.2521 n 09 ( refractive Ratio distribution type lens 2) r 18 = −50.9149 d 18 = 4.0284 r 19 = −11.5646 d 19 = 1.522 n 010 = 1.77250 ν 010 = 49.66 r 20 = −20.6898 Aspherical coefficient E = −0.11836 × 10 −4 , F = 0.13779 × 10 -7 G = −0.68096 × 10 -9 f 36.2 60.5 101.15 D 1 2.371 8.215 11.349 D 2 8.608 4.106 1.001 Refractive index distributed lens (n 08 ) n 0 n 1 d-line 1.60311 0.27 450 × 10 -4 C Line 1.60008 0.27547 × 10 -4 F line 1.61002 0.27224 × 10 -4 n 2 n 3 d line 0.26422 × 10 -4 0.61383 × 10 -6 C line 0.25920 × 10 -4 0.60210 × 10 -6 F line 0.27593 × 10 -4 0.64121 × 10 -6 gradient index lens 2 (n 09 ) n 0 n 1 d-line 1.69680 −0.15538 × 10 -2 C line 1.69297 −0.14799 × 10 -2 F line 1.70552 −0.17262 × 10 -2 n 2 n 3 d line −0.10118 × 10 -4 0.31305 × 10 -7 C line −0.10798 × 10 -4 0.33331 × 10 -7 F line −0.85303 × 10 -5 0.26578 × 10 -7 1 / ｛(f W ) 2 · n 1d · ν 1d ｝ = − 7.7862 × 10 -2 | ν 1d | = 6.3077, f n / f T = -0.1531 B w /Z=0.4152,n in 1d · (f W) 2 = -2.0361 above data, r 1, r 2, ... are radii of curvature of each lens surface, d 1, d 2, ... each Lens thickness and lens spacing, n
01 , n 02 ,... Are the refractive indexes of the respective lenses, and ν 01 , ν 02 ,... Are the Abbe numbers of the respective lenses.
又上記実施例で用いられる非球面の形状は、光軸方向
をｘ軸にこれと直交な方向をｙ軸にとった時式の式で表
わされる。Further, the shape of the aspherical surface used in the above embodiment is expressed by a formula in which the optical axis direction is set to the x-axis and the direction orthogonal thereto is set to the y-axis.
ただしｒは近軸曲率半径、E,F,G,H,…は非球面係数で
ある。 Here, r is a paraxial radius of curvature, and E, F, G, H,... Are aspherical coefficients.
実施例１のレンズ系の広角端，中間焦点距離，望遠端
における収差状況は夫々第６図，第７図，第８図に、実
施例２の広角端，中間焦点距離，望遠端における収差状
況は夫々第９図，第10図，第11図に、実施例３の広角
端，中間焦点距離，望遠端における収差状況は夫々第12
図，第13図，第14図に、実施例４の広角端，中間焦点距
離，望遠端における収差状況は夫々第15図，第16図，第
17図に、実施例５の広角端，中間焦点距離，望遠端にお
ける収差状況は夫々第18図，第19図，第20図に示す通り
である。尚、各収差図は、物点無限遠時のものである。The aberrations at the wide-angle end, the intermediate focal length, and the telephoto end of the lens system according to the first embodiment are shown in FIGS. 6, 7, and 8, respectively. FIGS. 9, 10 and 11 show the aberrations at the wide angle end, the intermediate focal length, and the telephoto end of the third embodiment, respectively.
FIG. 13, FIG. 13, and FIG. 14 show the aberrations at the wide angle end, the intermediate focal length, and the telephoto end of the fourth embodiment, respectively.
In FIG. 17, the aberrations at the wide angle end, the intermediate focal length, and the telephoto end of the fifth embodiment are as shown in FIGS. 18, 19, and 20, respectively. Each aberration diagram is for an object point at infinity.
［発明の効果］ 以上詳細に説明したように、本発明の変倍レンズは、
変倍比が約３で広角端から望遠端にかけて諸収差が十分
良好に補正されていて、しかも全長が非常に短いコンパ
クトなレンズ系である。[Effect of the Invention] As described in detail above, the variable power lens of the present invention
This is a compact lens system with a variable power ratio of about 3, and various aberrations are sufficiently satisfactorily corrected from the wide-angle end to the telephoto end, and the total length is very short.
第１図乃至第５図は夫々本発明の実施例１の断面図、第
６図乃至第８図は実施例１の収差曲線図、第９図乃至第
11図は実施例２の収差曲線図、第12図乃至第14図は実施
例３の収差曲線図、第15図乃至第17図は実施例４の収差
曲線図、第18図乃至第20図は実施例５の収差曲線図であ
る。1 to 5 are cross-sectional views of the first embodiment of the present invention, FIGS. 6 to 8 are aberration curve diagrams of the first embodiment, and FIGS.
11 is an aberration curve diagram of the second embodiment, FIGS. 12 to 14 are aberration curve diagrams of the third embodiment, FIGS. 15 to 17 are aberration curve diagrams of the fourth embodiment, and FIGS. 18 to 20. 14 is an aberration curve diagram of the fifth embodiment.
Claims (1)
配置した複数のレンズ群よりなり、前記負の屈折力を有
するレンズ群が負の屈折力を有するレンズのみの少なく
とも２枚のレンズにて構成されそのうちの少なくとも１
枚のレンズが以下の条件（１）、（２）を満足するラジ
アル型屈折率分布型レンズであるコンパクトな変倍レン
ズ。 （１） 1/｛（fW）２・n1d・ν1d｝＜０ ただし、ν1d＝n1d/（n1F−n1C） （２） ｜ν1d|＜50 ここで、fWは広角端における全系の焦点距離、n1d、
n1F、n1Cはそれぞれ、ｄ線、Ｆ線、Ｃ線の屈折率分布式
の２次の係数である。1. A lens system comprising a plurality of lens units having a lens unit having a negative refractive power closest to the image side, wherein the lens unit having a negative refractive power is at least two lenses each including only a lens having a negative refractive power. Composed of lenses and at least one of them
A compact variable power lens in which the number of lenses is a radial type gradient index lens satisfying the following conditions (1) and (2). (1) 1 / ｛(f W ) 2 · n 1d · ν 1d ｝ <0, where ν 1d = n 1d / (n 1F −n 1C ) (2) | ν 1d | <50 where f W is The focal length of the whole system at the wide-angle end, n 1d ,
n 1F and n 1C are the quadratic coefficients of the refractive index distribution equations for the d-line, F-line, and C-line, respectively.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1150588A JP2607957B2 (en) | 1989-06-15 | 1989-06-15 | Compact zoom lens |
| US07/537,780 US5117309A (en) | 1989-06-15 | 1990-06-14 | Vari-focal lens system having graded refractive index lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1150588A JP2607957B2 (en) | 1989-06-15 | 1989-06-15 | Compact zoom lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0317609A JPH0317609A (en) | 1991-01-25 |
| JP2607957B2 true JP2607957B2 (en) | 1997-05-07 |
Family
ID=15500170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1150588A Expired - Fee Related JP2607957B2 (en) | 1989-06-15 | 1989-06-15 | Compact zoom lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2607957B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3260798B2 (en) * | 1991-03-04 | 2002-02-25 | オリンパス光学工業株式会社 | Wide-angle zoom lens |
| JP3204703B2 (en) * | 1991-11-27 | 2001-09-04 | オリンパス光学工業株式会社 | Zoom lens |
| JP3262398B2 (en) * | 1993-02-25 | 2002-03-04 | キヤノン株式会社 | Small zoom lens |
| JP3412939B2 (en) * | 1994-12-22 | 2003-06-03 | キヤノン株式会社 | Zoom lens |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60159817A (en) * | 1984-01-31 | 1985-08-21 | Canon Inc | Chromatic aberration compensating method |
| JPS61295524A (en) * | 1985-06-25 | 1986-12-26 | Canon Inc | Variable focal length lens |
-
1989
- 1989-06-15 JP JP1150588A patent/JP2607957B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0317609A (en) | 1991-01-25 |
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