JPS5885409A

JPS5885409A - Photomicrographic lens

Info

Publication number: JPS5885409A
Application number: JP18222681A
Authority: JP
Inventors: Yoshito Yuma; 嘉人遊馬
Original assignee: Olympus Corp; Olympus Optical Co Ltd
Current assignee: Olympus Corp
Priority date: 1981-11-16
Filing date: 1981-11-16
Publication date: 1983-05-21

Abstract

PURPOSE:To obtain a lens system suitable for photomicrography by using 4 lenses so as to especially correct the distortion aberration. CONSTITUTION:A lens system is composed of the 1st single or joined lens having the stronger surface at the image side, the 2nd biconvex lens, the 3rd negative lens having the concave surface at the object side and the 4th biconvex lens, and conditions 1-4 are satisfied.

Description

【発明の詳細な説明】本発明は顕微鏡の対物レンズにて形成された物体像をフ
ィルム面上に再結像させて写真撮影を行なう顕微鏡写真
撮影レンズに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microscope photography lens that takes a photograph by re-imaging an object image formed by an objective lens of a microscope on a film surface.

顕微鏡で規則正しいパターンの写真を撮るどき、従来の
装置ではレンズ系の歪曲収差か大きいために直線が歪ん
で直線として写らない欠点があった。When taking pictures of regular patterns using a microscope, conventional devices had the disadvantage that straight lines were distorted and did not appear as straight lines due to large distortions in the lens system.

それは従来の顕微鏡写真撮影レンズは歪曲収差がプラス
になっており、一方はとんどの対物レンズが歪曲収差か
プラスである。したがって対物レンズを含めた光学系全
体として歪曲収差が犬に々るためである。This is because conventional microphotography lenses have positive distortion, while most objective lenses have positive distortion. This is because the entire optical system including the objective lens is subject to distortion.

例えば従来の顕微鏡写真撮影レンズとして特開φ＼゛昭５４−１１７５４号公報に記載されたものであるが、
このレンズの歪曲収差は最収辺で約＋３％である。For example, a conventional microscopic photography lens is described in Japanese Patent Application Laid-Open No. 11754/1983.
The distortion aberration of this lens is about +3% at the most focused side.

しだがって、歪曲収差のもつとも少ない顕微鏡写真が撮
影できるためには、顕微鏡写真撮影レンズと組合わせて
使用される数種の顕微鏡対物レンズの平均的な歪曲収差
を口も消すような顕微鏡写真撮影レンズを使用し両者で
打ち消し合って全系で零になるようにするのが望ましい
。Therefore, in order to be able to take microscopic photographs with minimal distortion, it is necessary to take microscopic photographs that eliminate even the average distortion of the several types of microscope objective lenses used in combination with the microscopic photography lens. It is desirable to use a photographic lens so that the two cancel each other out so that the total value becomes zero.

上述のように多くの対物レンズは、その特性上止の歪曲
収差を有し、その値は例えば視野数１０のところで＋０
１〜」−０５％程度である。したがってその範囲を写す
撮影レンズとしては、歪曲収差が０〜−０５％の範囲の
もので、しかも周辺まで十分平坦な像が得られるものが
望ましい。As mentioned above, many objective lenses have a certain amount of distortion due to their characteristics, and the value is, for example, +0 at a field of view of 10.
It is about 1-05%. Therefore, it is desirable that a photographing lens capable of photographing this range has a distortion aberration in the range of 0 to -05% and can obtain a sufficiently flat image up to the periphery.

本発明は以上の点に鑑みなされたもので、歪曲収差の値
が零に近いか或は負であってしかも周辺まで十分平坦な
像が得られるようにした顕微鏡写真撮影レンズを提供す
るものである。The present invention has been made in view of the above points, and it is an object of the present invention to provide a microscopic photography lens that has a distortion value close to zero or is negative, and that can obtain a sufficiently flat image up to the periphery. be.

本発明の顕微鏡写真撮影レンズは、第１図に示すような
構成のレンズ糸つ捷り、像側に強い面を有する正の単レ
ンズ又は接合レンズの第１群レンズと、両凸レンズの第
２群レンズと、物体側に凹面を有する負レンズの第３群
レンズと、両凸レンズの第４群レンズとより構成されて
いる。そして次の各条件を満足するようにしたものであ
る。The microscopic photography lens of the present invention has a lens structure as shown in FIG. It is composed of a group lens, a third group lens which is a negative lens having a concave surface on the object side, and a fourth group lens which is a biconvex lens. It is designed to satisfy the following conditions.

（１）　　２．６≦ｆ＋／ｆ２３４≦４６（２）０．９
２≦ｄ２／ｆ　≦１：３（３）　　　０．１　≦ｄ４／ｆ（４）１．６５≦（ｎｚ　＋１１４　）／　まただしｆ
は全系の焦点距ｆｉ’ｆｆ、ｆａｉｌ第１群レンズの焦
点距離、ｆ２３４は第２群レンズ、第３群レンズ。(1) 2.6≦f+/f234≦46 (2) 0.9
2≦d2/f≦1:3 (3) 0.1≦d4/f (4)1.65≦(nz +114)/ Matadashi f
is the focal length of the entire system fi'ff, fail is the focal length of the first group lens, and f234 is the second group lens and third group lens.

第４群レンズの合成焦点距離、ｄ２←１、第１群レンズ
と第２群レンズの間の空気間隔、ｄ４ｉｌ−１、第２群
レンズと第３群レンズの間の空気柑竺、ｎｚ・ｎ５は第
２群レンズおよび第４群レンズの屈折率である。Synthetic focal length of the 4th group lens, d2←1, Air distance between the 1st group lens and 2nd group lens, d4il-1, Air distance between the 2nd group lens and 3rd group lens, nz・n5 is the refractive index of the second group lens and the fourth group lens.

次に」−記者条件について詳細に説明する。Next, we will explain the reporter conditions in detail.

条件（１）はレンズ系の屈折力配分を規定するものであ
り、歪曲収差の値を決定する１、で大きな役割を果すも
のである。それは歪曲収差にとって屈折力の配分が重要
な要素となるからである１、この条件で上限をこえると
歪曲収差はマイナスになりすぎ、又下限をこえるとプラ
スになりすきでし捷う。Condition (1) defines the refractive power distribution of the lens system, and plays a major role in determining the value of distortion. This is because the distribution of refractive power is an important factor for distortion.1 Under these conditions, if the upper limit is exceeded, the distortion becomes too negative, and if the lower limit is exceeded, the distortion becomes too positive.

条件（２）は第１群レンズと第２群レンズの間の空気間
隔を規定するもので、これによって像面彎曲をコントロ
ールシ、かつコマ収差のバランスヲトるだめのものであ
る。この条件で下限をこえると像面彎曲が大きくなり（
ペッツバール和がプラスになり）、寸だコマの対称性が
悪化する。逆に」二限をこえると像面彎曲は小さくなり
、設計上特別大きな問題とはならないが、レンズ径が大
きくなるだめに実用上は好捷しくない。尚像面彎曲、コ
マ収差を適正なものにするだめには、第３群レンズの肉
厚を調整することも効果がある。Condition (2) defines the air gap between the first group lens and the second group lens, thereby controlling the curvature of field and balancing coma aberration. If the lower limit is exceeded under these conditions, the field curvature increases (
The Petzval sum becomes positive), and the symmetry of the small pieces deteriorates. On the other hand, if the curvature of field exceeds the 2 limit, the curvature of field becomes small, which is not a particularly big problem in terms of design, but it is not practical as the lens diameter increases. It is also effective to adjust the thickness of the third group lens in order to make the field curvature and coma aberration appropriate.

条件（３）はコマ収差を良好に補正するために設けたも
のである。この条件よりはずれると、コマ収差の対称性
が悪化し、これを他の部分で補正しようとすると周辺で
の非点隔差（メリデイオナル像面がプラス側に曲がる）
が犬になって他の部分で補正しきれなくなる。Condition (3) is provided to properly correct coma aberration. If this condition is exceeded, the symmetry of comatic aberration deteriorates, and if you try to correct it in other areas, there will be astigmatism in the periphery (the meridional image surface will curve to the plus side).
becomes a dog and cannot be compensated for in other areas.

条件（４）は像面彎曲を大きく（ペッツバール和かプラ
スになる）しないためと同時に、非点隔差を発生させな
いために必要な条件である。したがってこの条件をはず
れると像面彎曲が犬になり、又非点隔差が生ずるので好
壕しくない。Condition (4) is necessary to prevent the field curvature from becoming large (the Petzval sum becomes positive) and at the same time to prevent astigmatism difference from occurring. Therefore, if this condition is not met, the curvature of field becomes dog-like, and astigmatism difference occurs, which is not desirable.

第１群レンズは単体のレンズでも接合レンズでもよい。The first group lens may be a single lens or a cemented lens.

単体のレンズの場合、軸」−色収差と倍率色収差とのバ
ランスをとるために分散の大きい硝材を使わざるを得な
い。しかし分散の大きい硝材の中には分光透過率の重重
しくないものもある。In the case of a single lens, a glass material with large dispersion must be used in order to balance axial chromatic aberration and lateral chromatic aberration. However, some glass materials with large dispersion do not have a heavy spectral transmittance.

したがって第１群レンズを接合レンズにすれば」−述の
点では非常に便利である。その上球面収差や軸外収差も
更に改善させることができる。Therefore, if the first group lens is a cemented lens, it will be very convenient from the point mentioned above. Moreover, spherical aberration and off-axis aberration can also be further improved.

次に以」二説明した本発明顕微鏡写真撮影レンズの各実
施例を示す。Next, embodiments of the microscopic photography lens of the present invention described below will be shown.

実施例１ｒ　＋　＝　　４．５５３９／　りｒり７２ｄ、　＝　０．２２７８　１＋　＝　拌器利　　νｌ　
＝　２５．７１ｒ２　＝　−１，７７６６ｄ２　＝　１．１０５８ｒ、＝２００１４ｄ３””　０．０８２８　　ｎ２　＝　１．７２６００
　１’２　＝　５３．５６ｒ４＝　−０，９４７０ｄ４＝　０．１６５７ｒ５　＝　　ｏ、　４０６１ｄｉ　＝　（１０８２８ｎ３＝　１．７１．７３６　　
’ｓ　＝２９．５１ｒ６　＝　０．８０２５ｄａ　　”’　０．１６９８　　ｎ４　　＝　１．６２
０４１　１’４　−６０．２７ｒ７　−”　　　ｏ、　
８５］−３ｄ７　＝　　０．０４１４ｒ８　＝　１．８６０１ｄ８　＝　　０．１０３５　　　ｎ５　　＝　　１．７
２０００　　　し５　　＝　　４６．０３ｒ９−＝　−
０，８７８７ｆ−１，βニー５　、Ｌ／ｌｈａ＜−３，５８３実施例
２ｒ、　＝　−１０，１，６２３ｄ＋　＝　０．２２６２　　ｎ＋　＝　ｌ　７８４７２
　　ν、　＝　２５．７１ｒ　２　＝　　１．８７６０ｄ２＝　０．９６６５ｒ　３　＝　２．１６０６ｄｓ　”　０．０９０５　　ｎ２　＝　１．７２６００
　１’２　＝　５３．５６ｒ４　ニー　０．９２１４ｄ、二０．１５６３ｒ、　＝−０，４，０７６ｄ５−”　０．０８２３　　ｎａ　＝　１．７１７３６
　　シＡ−２９．５１ｒ６　””　ｏ、　８０２１ｄ６　””　０．１９３３　１４　＝　１．６２０４］
シ４　＝　６０．２７ｒ７　＝　　　０．８９２０ｄ７　＝　０．０１２３ｒ８　＝　　１．７２９９ｄ８−０．１．０２８　　ｎ５　＝”　１．７２０００
　　ν５　＝　４６．０３ｒ９　＝　　　０．８８１９ｆ二１．β＝　　５　、Ｌ／ｆｚａ４＝？８９７実施例
３ｒ　、　＝　−３，０２２１ｄ、　＝　０．２０６５　　ｎ、　＝　１．８０５１８
　　ｖ、　＝　２５．４．３ｒ２＝　−ｉ、　６４５０ｄ２二１．２３９２ｒ、ｌ　＝　１．９２０９ｄ３　＝　０．０９０９　１２＝　１．７８６５０　　
ν２　”’　５０．００ｒ４　”−”　　ｔ　０３０４ｄ、　＝　０．１．９４１ｒ、＝−０３９９７ｄ、＝　０．０６６１　０．＝　１．６９８９５　　ν
、　＝　３０．１２ｒ、ｌ＝　０．８１００ｄｌｌ＝　０．１９０Ｏｎ、　：＝：　１．６０７２９
　　ν、　＝　５９．３８ｒ７−−０９２６９ｄ７二００３３０ｒＢ　　”’　　］、、８６０６ｄａ　”　０．０９９Ｉ　　ｎ＊　＝　１．７４１００
　　ν５　＝　５２．６８ｒ、、＝　−０，８７５３ｆ−１、β＝　−５、ｆ　、／ｆ２：１４　＝　４．２
０２実施例４　　　′ ｒ　１ａ＝　　　４．９２２６ｄ＋ａ　＝　０．０６３４　　ｎ＋ａ　””　１．７４
１００　　シ、ａ＝　５２．６８ｒｌｌ）　＝　０．４
．８３４ｄ、ｂ＝　０．１６９１．　　ｎ１ｌ）　＝　１．７８
５９０　　ν市＝　４４．１−８ｒ２　　＝　　　２．
６８９６ｄ２二１．１２８８ｒ３　＝　　２．７２１９ｄ３　＝　０．０８４６　１１２　　＝　　１．．７３
４００　　　ν２　　＝　　５１．４９ｒ４　　＝＝　
　　１．０２７８ｄ、二０．１３５３ｒ５−　　ｏ、４１７１ｄｉ　””　０．０８４６　１：＋　＝　１．６８８９
３　　’＋（＝　３１．０８ｒａ　　＝　ｏ、７９４７ｄａ　””　０．１７３３　　）Ｌ＋　＝　１．６２０
４１．　　’ａ　＝　６０．２７］−７＝　　　０．７
５２４ａ７　＝　　０．０４２３ｒ８二２．７４３］ｄｓ−０，１０５７ｎ！’＋　’−１，７２（１００ν
、　＝　５０．２５ＴＯ−’　　　　０．９２４４ｆ−１、β＝　　　５　　、ｆｌ／’ｆ２：１４　＝　
４．１９７ただしｒｌ　ｒ　ｒ２ｒ　”’　Ｊ　ｌ”Ｏ
Ｉ：Ｊレンズ各面の曲率半径、ｄ１＋　ｄ２　ｒ”’＋
　ｄ８は各レンズの肉厚および空気間隔、ｎｌ　＋　１
２　＋　”’　＋　ｎ、ｄ、各レンズの屈折率、ν１　
、ν２．　　、ν、は各レンズのアツベ数、βは倍率で
ある。Example 1 r + = 4.5539 / Riri72 d, = 0.2278 1+ = Stirrer efficiency νl
= 25.71r2 = -1,7766 d2 = 1.1058 r, =20014 d3"" 0.0828 n2 = 1.72600
1'2 = 53.56r4 = -0,9470 d4 = 0.1657 r5 = o, 4061 di = (10828n3 = 1.71.736
's = 29.51r6 = 0.8025 da "' 0.1698 n4 = 1.62
041 1'4 -60.27r7 -" o,
85]-3 d7 = 0.0414 r8 = 1.8601 d8 = 0.1035 n5 = 1.7
2000 5 = 46.03r9-= -
0,8787 f-1, β knee 5, L/lha<-3,583 Example 2 r, = -10,1,623 d+ = 0.2262 n+ = l 78472
ν, = 25.71r 2 = 1.8760 d2 = 0.9665 r 3 = 2.1606 ds ” 0.0905 n2 = 1.72600
1'2 = 53.56r4 knee 0.9214 d, two 0.1563 r, = -0,4,076 d5-" 0.0823 na = 1.71736
Shi A-29.51r6 ”” o, 8021 d6 ”” 0.1933 14 = 1.6204]
C4 = 60.27r7 = 0.8920 d7 = 0.0123 r8 = 1.7299 d8-0.1.028 n5 =” 1.72000
ν5 = 46.03r9 = 0.8819 f21. β=5, L/fza4=? 897 Example 3 r, = -3,0221 d, = 0.2065 n, = 1.80518
v, = 25.4.3r2= -i, 6450 d22 1.2392 r,l = 1.9209 d3 = 0.0909 12 = 1.78650
ν2 ”' 50.00r4 ”-” t 0304 d, = 0.1.941 r, = -03997 d, = 0.0661 0. = 1.69895 ν
, = 30.12r, l = 0.8100 dll = 0.190On, :=: 1.60729
ν, = 59.38r7--09269 d7200330 rB ``' ], , 8606 da '' 0.099I n* = 1.74100
ν5 = 52.68r,, = -0,8753 f-1, β = -5, f, /f2:14 = 4.2
02 Example 4 ′ r 1a = 4.9226 d+a = 0.0634 n+a ”” 1.74
100 shi, a= 52.68rll) = 0.4
．． 834 d,b=0.1691. n1l) = 1.78
590 ν City = 44.1-8r2 = 2.
6896 d2 2 1.1288 r3 = 2.7219 d3 = 0.0846 112 = 1. ．． 73
400 ν2 = 51.49r4 ==
1.0278 d, 2 0.1353 r5- o, 4171 di ”” 0.0846 1:+ = 1.6889
3 '+ (= 31.08ra = o, 7947 da "" 0.1733) L+ = 1.620
41. 'a = 60.27]-7 = 0.7
524 a7 = 0.0423 r8 two 2.743] ds-0,1057n! '+'-1,72 (100ν
, = 50.25TO-' 0.9244 f-1, β= 5, fl/'f2:14 =
4.197However, rl r r2r ”' J l”O
I: Radius of curvature of each surface of J lens, d1+ d2 r”'+
d8 is the wall thickness and air spacing of each lens, nl + 1
2 + ”' + n, d, refractive index of each lens, ν1
, ν2. , ν is the Atsube number of each lens, and β is the magnification.

以上の説明および各実施例１ニリ明らかなように本発明
によれば写真撮影の時の歪曲がほぼ零で周辺捷でフラッ
トな像がイＮＩられる顕微鏡写真撮影レンズを実現し得
る。As is clear from the above description and each of the first embodiments, according to the present invention, it is possible to realize a microscopic photography lens that has almost zero distortion during photography and can produce flat images with sharp edges.

[Brief explanation of drawings]

第１図は本発明写真撮影レンズの断面図、第２図乃至第
５図は夫々本発明の実施例１乃至実施例４の収差曲線図
である。球面収差　　　　非点収差　　　歪曲収差−５４− 輔１−の色」１ノ、ζニ　　　　コマ収差−２，０２，
０−１球面収差　　　非点収差　　　歪曲収差、！仙１−の色
Ｊｌｙ不　　　　　コ　マＪＩＬ！　差−２，０２，０
−１球面収差　　　非点収差　　　歪曲収差５５− 第４図１１′山−にの已１ｉ　１／　、、’；’（、コ　　マ
　ＩＩＭ　　　ぷ三−２，０２，０−１球面収差　　　非点収差　　　歪曲収差輔−１−の色収
差　　　　　　コ　−′収差−２，Ｑ　　　　　　　　
　　２．０　　　　　　　−１手続補正書（自’５１　
）１旧任５７年２月１０１］特許庁長官殿１　事件の表示昭第１５６年特許願第１．８２２２６号２　発明の名称顕微′境写自撮影レンズ３、補正をする者事件との関係　　　特許出ｊ幀人東京都港区虎ノ門２の４１３の２（０３７）　　オリンパス光学工業株式会社代表者　北
　村　茂　男４代理人東京都港区虎ノ門２−５−２電話　東京（５８０）　５６４．１　　　ｉ、ｉ−”＋
（７５８６）　　弁理士　向　　　　政　−１５補正の
対象明卸１外の＠πト１清〉１２：の範囲、発明の詳細な説
明の）Ｍ！ｌお・よび図［ｍ６、補ＩＥの内容（１）特許請求の範囲を別紙の通りに補正する。（２）明細卦２頁］５行目の「最収辺１を「最周辺」に
訂正する。（８）明細Ｖ＋３頁１４行目乃至１５行目の［像側に強
い面を有する］を「物体１別面よりも像側面の方がパワ
ーが強いｊど訂正する。（４）図面中框２図乃至第５図を別紙の圃りに補正する
。特許請求の範囲物体側面よりも像側面の方がパワーが強い正レンズの第
１群レンズと、両凸レンズの第２群レンズと、物体側に
凹面を有する負レンズの第１群レンズト、両凸レンズの
第４群レンズとよりなす次の各条件を満足する顕微鏡写
真撮影レンズ。（］）２．６　≦　ｆＩ／ｆ　２　：＋　４　　≦　４
．６（２）　０．９２；倶　ｄ２／ｆ　　≦　１．；３
（３１０，１≦　ｄ　、Ｉ／ｆ（４Ｊ　　１．６５　　≦　（１２−＋　ｎ５）／　ま
ただしｆは全系の焦点距離、ｒ　＋　（ｔ：Ｆ、第１群
レンズの焦点距離、ｆ　２３４　　は第２群レンス゛、
第；つ群レンズ、第４群レンズの合成焦点路ｆ４１１、
ｄ２は第１群レンズと第２群レンズの間の空気間隔、ｄ
ｌは第２群レンズと第３群レンズの間の空気間隔、＋１
２．ｎ５は夫々第２群レンズおよび第４群レンズの屈折
率である。第球面収差　　　非点収差　　　歪曲収差５７− １２図倍率の色収差　　　　　コ　マ収差第球面１ｉ７差　　　非点収差　　　歪曲Ｊ１．Ｉｊ差Ｓ
図４１゛居・・す（２収差　　　　　″　１′収差−１Ｊ
Ｊ　　　　　　　　　　　　　Ｚ（Ｊ　　　　　　　　
　　　−１〕犬ｒ１１７４１Ｉ差　　非点収差　　　歪
曲収差５８− 倍率の色収差　　　　　コ　マ収差球回収フ″′　　　　非点＋１ノ差　　　歪曲すＶ差第
５図イ碓！ｌのにｇ；Ｌ’！；を二　　　　コマ収差５９−FIG. 1 is a sectional view of the photographic lens of the present invention, and FIGS. 2 to 5 are aberration curve diagrams of Examples 1 to 4 of the present invention, respectively. Spherical aberration Astigmatism Distortion aberration -54- Color of 1-1, ζni Comatic aberration -2,02,
0-1 Spherical aberration Astigmatism Distortion aberration,! Sen 1-'s color Jly non-piece JIL! Difference -2,02,0
-1 Spherical aberration Astigmatism Distortion 55- Fig. 4 11' Mountain 1i 1/ ,,';'(, Coma IIM P3-2,02,0-1 Spherical aberration Astigmatism Distortion Chromatic aberration of aberration -1 - co -' aberration -2,Q
2.0 -1 Procedural amendment (from '51)
) 1 Previously appointed February 101, 1957] Dear Commissioner of the Japan Patent Office 1 Indication of the case Patent Application No. 1.82226 of 1989 2 Name of the invention Microscopic self-photographing lens 3. Person making corrections Relationship to the case Patent issuer 2-413-2 Toranomon, Minato-ku, Tokyo (037) Olympus Optical Industry Co., Ltd. Representative Shigeru Kitamura Male 4 Agent 2-5-2 Toranomon, Minato-ku, Tokyo Telephone Tokyo (580) 564.1 i, i-”+
(7586) Patent Attorney Mukai Masa -15 Subject of amendment @πto1 Kiyo>12: scope of the detailed description of the invention) M! l and Figure [m 6, Contents of Supplementary IE (1) The claims are amended as shown in the attached sheet. (2) Specification, page 2] In the 5th line, ``Most profitable side 1'' is corrected to ``most marginal''. (8) Correct [having a strong surface on the image side] in lines 14 and 15 on page V+3 to "Object 1 has stronger power on the image side than on the other side." (4) Center frame in the drawing Figures 2 to 5 are corrected to the attached page.Claims include a first group lens that is a positive lens whose power is stronger on the image side than on the object side, a second group lens that is a biconvex lens, and an object. A microphotography lens that satisfies the following conditions, consisting of a first group lens which is a negative lens having a concave surface on its side and a fourth group lens which is a biconvex lens.(])2.6≦fI/f2:+4≦ 4
．． 6(2) 0.92; d2/f ≦ 1. ;3
(310, 1≦d, I/f (4J 1.65≦(12-+n5)/ f is the focal length of the entire system, r + (t:F, focal length of the first group lens, f 234 is the second group lens,
Synthetic focal path f411 of the 4th group lens and the 4th group lens;
d2 is the air distance between the first group lens and the second group lens, d
l is the air distance between the second group lens and the third group lens, +1
2. n5 is the refractive index of the second group lens and the fourth group lens, respectively. Spherical aberration Astigmatism Distortion aberration 57-12 Chromatic aberration of magnification Comatic aberration Spherical 1i7 difference Astigmatism Distortion J1. Ij difference S
Figure 41゛... (2 aberrations ``1' aberrations -1J
JZ(J
-1] dog r11741I difference astigmatism distortion aberration 58- chromatic aberration of magnification coma aberration ball recovery f''' astigmatism +1 difference distorted V difference Fig. 5 A! L's g; L'!; Coma aberration 59-

Claims

[Claims] A first lens group that is a positive lens having a strong power surface on the image side, a second group lens that is a biconvex lens, a third lens group that is a negative lens that has a concave surface on the object side, and a biconvex lens. A microscopic photography lens which is made up of a fourth group lens and satisfies each of the following conditions. (1) 2.6≦fl/f23a≦46 (2) 0.9
2≦d2/f≦13(3) 0.1≦d4/f (4) ],, 65≦(n2+n5)/Madashi f
is the focal length of the entire system, fl is the focal length of the first group lens, f
23. are the second group lens and the third group lens. The composite focal length of the fourth group lens, d2 is the air distance between the first group lens and the second group lens, 'd4 is the air distance between the second group lens and the third group lens, n2 + n5 is the Second
This is the refractive index of the group lens and the fourth group lens.