JPH02257113A - Lens system for copying device - Google Patents

Lens system for copying device

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Publication number
JPH02257113A
JPH02257113A JP8011989A JP8011989A JPH02257113A JP H02257113 A JPH02257113 A JP H02257113A JP 8011989 A JP8011989 A JP 8011989A JP 8011989 A JP8011989 A JP 8011989A JP H02257113 A JPH02257113 A JP H02257113A
Authority
JP
Japan
Prior art keywords
lens
lens system
focal length
lenses
glass material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP8011989A
Other languages
Japanese (ja)
Other versions
JP2867413B2 (en
Inventor
Keijirou Sakamoto
坂本　圭治朗
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minolta Co Ltd
Original Assignee
Minolta Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minolta Co Ltd filed Critical Minolta Co Ltd
Priority to JP1080119A priority Critical patent/JP2867413B2/en
Publication of JPH02257113A publication Critical patent/JPH02257113A/en
Priority to US07/794,355 priority patent/US5204780A/en
Application granted granted Critical
Publication of JP2867413B2 publication Critical patent/JP2867413B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Abstract

PURPOSE:To provide a lens system which is reduced in cost and is compact by constituting the lens of a 1st lens which is a positive meniscus lens, a 2nd lens which has a negative powder and a 3rd lens which has a positive power, and using plastic lenses for the 2nd lens and the 3rd lens. CONSTITUTION:At least two elements among three elements of the lens system of radii of curvature r1 to r6 having the constitution of 3 elements in 3 groups constituted, successively from an object side on the left side, the 1st lens of the positive meniscus lens the convex face of which is directed to the object side, the 2nd lens of a biconcave lens and the 3rd lens of a biconvex lens are constituted of plastic lenses. The cost of the lens system is reduced and the weight thereof is largely reduced by using the plastic lenses for at least the two elements among the three elements in such a manner. The lens performance of such lens system is equiv. to or higher than the performance of the conventional lens system and the formation of the compact lens to the smaller entire thickness of the lens is possible. The lens of the smaller size and weight is thus obtd. at the lower cost. The lens system having the good performance is obtd. while the number of the lens elements is decreased.

Description

【発明の詳細な説明】 ［産業上の利用分野］ この発明は、複写装置に使用される３群３枚構成のコン
パクトなレンズ系に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a compact lens system having three lenses in three groups and used in a copying machine.

［従来の技術および発明が解決しようとする課題］ 従来、複写装置等のレンズ系は、一般に４〜６枚のレン
ズから構成されている。また、複写装置等のレンズ系は
等倍額域で使用され、歪曲収差等を抑えるために対称型
のレンズ系に構成されているのが一般的である。（例え
ば、特開昭５９４５４１８号公報および特開昭５９−９
０８１．１号公報参照） 近年、このような複写装置の小型化に伴なってその光学
系も小型化・軽量化およびコストダウンの要望が益々強
くなっており、レンズ枚数を減らしながら性能の良好な
レンズ系が求められている。[Prior Art and Problems to be Solved by the Invention] Conventionally, a lens system of a copying machine or the like is generally composed of four to six lenses. Further, lens systems of copying machines and the like are used in the same magnification range, and are generally constructed as symmetrical lens systems in order to suppress distortion and the like. (For example, JP-A-5945418 and JP-A-59-9
(Refer to Publication No. 081.1) In recent years, as such copying devices have become smaller, there has been an increasing demand for smaller, lighter, and lower cost optical systems. A lens system is required.

しかし、これまで３枚レンズ構成の複写装置用レンズ系
は存在していなかった。However, until now, there has been no lens system for copying machines with a three-lens configuration.

この発明は、このような点に鑑みてなされたもので、レ
ンズ枚数を減らしてコストダウンを図るとともに、コン
パクトで、かつ、性能のよい複写装置用レンズ系を提供
することを目的とする。The present invention has been made in view of the above points, and an object of the present invention is to provide a lens system for a copying device that is compact and has good performance, while reducing the number of lenses to reduce costs.

［課題を解決するだめの手段および作用］この発明では
、片側から順に、レンズ系の外側に凸面を向けた正メニ
スカスレンズの第１レンズと、負のパワーをもつ第２レ
ンズと、正のパワーをもつ第３レンズとから構成される
３群３枚構成のレンズ系において、少なくとも上記３枚
のレンズのうち２枚はプラスチックレンズで構成したこ
とを特徴とする複写装置用レンズ系である。[Means and effects for solving the problem] In this invention, in order from one side, a first lens of a positive meniscus lens with a convex surface facing the outside of the lens system, a second lens with a negative power, and a second lens with a positive power. The present invention is a lens system for a copying apparatus, characterized in that in a lens system having three lenses in three groups and a third lens having a third lens, at least two of the three lenses are made of plastic lenses.

３枚のレンズ中２枚をプラスチックレンズな使うことで
レンズ系のコストダウンと大幅な軽量化が可能となり、
かつ、レンズ性能は従来のレンズ系と同等以上とし、レ
ンズ全厚を短くコンバク１−に形成することができ、ひ
いては複写装置全体の小型化にも寄与することができる
。By using two of the three lenses as plastic lenses, it is possible to reduce the cost and weight of the lens system.
In addition, the lens performance is equal to or better than that of conventional lens systems, and the total lens thickness can be shortened to a compact size, thereby contributing to miniaturization of the entire copying apparatus.

［実　施　例］ 以下、この発明の実施例を図面に基づいて説明する。[Example] Embodiments of the present invention will be described below based on the drawings.

第１図、第３図、第５図および第７図は、それぞれ実施
例工ないし実施例４のレンズ構成を示す断面図で、左側
の物体側から順に、物体側に凸面を向けた正メニスカス
レンズの第１レンズ１両凹レンズの第２レンズおよび両
凸レンズの第３レンズから構成される３群３枚構成のレ
ンズ系で、ＦナンバーＦ１０５画角２ω＝４５２°のレ
ンズ系である。1, 3, 5, and 7 are cross-sectional views showing the lens configurations of Examples to Example 4, respectively, and in order from the object side on the left side, a positive meniscus with a convex surface facing the object side. It is a lens system with three elements in three groups, consisting of a first lens, a second lens that is a biconcave lens, and a third lens that is a biconvex lens, and has an F number of F105 and an angle of view 2ω = 452°.

この発明の態様項２のレンズ系は、全系の焦点距離をｆ
、第１レンズと第２レンズ間の空気間隔なｄ２　第２レ
ンズと第３レンズ間の空気間隔をｄ４．第１レンズの焦
点距離をｆｌ、第２レンズの焦点距離をｆ７．第、バラ
ンスの硝材のｄ線での屈折率をＮ１．第Ｊレンズの硝材
のアツベ数を１ノ、とするとき、 ■　０．０１５ｆ＜ｄ２＜０．０２５ｆ■　０．０５ｆ
＜ｄ４＜０．１５ｆ ■　０．０４ｆ＜ｆ、＋ｆ、＜０．０６ｆ■　１．６５
＜Ｎ ■　　　３５　〈　っノ　、　〈　５０の各条件式を満
足さセる。In the lens system according to aspect 2 of the present invention, the focal length of the entire system is f
, the air distance between the first lens and the second lens is d2, and the air distance between the second lens and the third lens is d4. The focal length of the first lens is fl, the focal length of the second lens is f7. The refractive index of the balance glass material at the d-line is N1. When the number of glass materials of the J lens is 1, ■ 0.015f<d2<0.025f■ 0.05f
<d4<0.15f ■ 0.04f<f, +f, <0.06f■ 1.65
<N ■ 35 〈 〈 〈 〈 〈 〈 50 conditions are satisfied.

上記条件式■は、第１レンズと第２レンズの軸上空気間
隔を定めるもので、この条件をはずれるといずれも歪曲
収差１倍率色収差をバランスよく補正することが困難で
ある。The above conditional expression (2) determines the axial air distance between the first lens and the second lens, and if this condition is violated, it is difficult to correct distortion and single-lateral chromatic aberration in a well-balanced manner.

上記条件式■は、第２レンズと第３レンズ間の空気間隔
を定めるもので、下限値を越えると、コマフレアの発生
量が大きくなり、像のコントラストが低下してしまう。The above conditional expression (2) determines the air distance between the second lens and the third lens, and if the lower limit is exceeded, the amount of coma flare will increase and the contrast of the image will decrease.

また、上限値を越えると、歪曲収差の補正が十分できな
くなってしまう。そして、レンズが大型化してしまうの
で望ましくな１７１゜ 上記条件式■は、第１レンズと第２レンズの焦点距離の
和を定めたもので、主に球面収差を抑えるための条件で
ある。上限値を越えると球面収差が補正過剰となる。ま
た、下限値を越えると球面収差が補正不足になると同時
に非点収差が大きくなり像面が倒れる。Furthermore, if the upper limit is exceeded, distortion cannot be sufficiently corrected. 171°, which is desirable because the lens becomes large.The above conditional expression (2) defines the sum of the focal lengths of the first lens and the second lens, and is mainly a condition for suppressing spherical aberration. If the upper limit is exceeded, spherical aberration will be overcorrected. Moreover, when the lower limit is exceeded, spherical aberration becomes insufficiently corrected, and at the same time astigmatism increases and the image plane collapses.

上記条件式■、■は、ともに第１レンズの硝材を定める
ための条件である。■の条件を外れると非点隔差が増大
する。また、コマ収差が十分に補正し切れなくなる。The above conditional expressions (1) and (2) are both conditions for determining the glass material of the first lens. If the condition (2) is not met, the astigmatism difference increases. Moreover, coma aberration cannot be sufficiently corrected.

また、■の条件を外れるといずれの場合も十分な色収差
を補正することができな（なる。Furthermore, if the condition (2) is not met, chromatic aberration cannot be sufficiently corrected in any case.

この発明の実施例１〜４のレンズ系は、３枚のレンズ中
２枚をプラスチックレンズで構成している。すなわち、
第２レンズをポリカーボネイト。In the lens systems of Examples 1 to 4 of the present invention, two out of three lenses are made of plastic lenses. That is,
The second lens is made of polycarbonate.

第３レンズをアクリルのプラスチックレンズを使用する
。そのため、軽量化および型でつくるので大量生産が可
能となった。また、非対称レンズ系でありながら歪曲収
差等も含めて、各収差を良好に補正したレンズ系となっ
ている。An acrylic plastic lens is used as the third lens. Therefore, mass production became possible because it was lightweight and made using molds. Furthermore, although it is an asymmetric lens system, it is a lens system in which each aberration, including distortion, is well corrected.

第１表、第２表、第３表および第４表は、実施例１ない
し実施例４の各レンズ構成を示す曲率半径、軸上面間隔
、硝材のｄ線での屈折率およびアツベ数の数値を示す。Tables 1, 2, 3, and 4 show the radius of curvature, axial distance, refractive index at the d-line of the glass material, and Atsube number values showing the lens configurations of Examples 1 to 4. shows.

第２図、第４図、第６図および第８図は、実施例ユない
し実施例４の一１×時の収差曲線図を示す。各実施例と
も焦点距離ｆ　＝１８０　ｍ　ｍ　＋　Ｆナンバー１０
．半画角ω＝２２．６°である。FIG. 2, FIG. 4, FIG. 6, and FIG. 8 show aberration curve diagrams of Examples Y to 4 at 1×. Focal length f = 180 mm + F number 10 in each example
．． The half angle of view ω=22.6°.

なお、実施例１ないし実施例４の上記各条件式の数値並
びにコンパクトさの指標となる全厚Σｄの数値を纏めて
第５表に示す。Table 5 summarizes the numerical values of each of the above-mentioned conditional expressions and the numerical value of the total thickness Σd, which is an index of compactness, for Examples 1 to 4.

（以下余白） 第　　　１ 表 ｆ＝１８０ ＦＮＯ，＝１０．　０ 曲率半径 軸上面間隔　　屈折率（Ｎｄ）　　７ツベ数（υｄ）ｒ
＋　　１６８．７５ ｄ２３．８０ ｒ、　　　３０．３６ ｄ４１８．１６ ｒｅ　−１３ｓ、２９ Σｄ　＝３６．６６ 第　　　２ 表 ｆ＝１８０ ＦＮＯ，＝１０．　０ 曲率半径　　　軸上面間隔　　屈折率（Ｎｄ）　　７’
・ン／（数（１〕ｄ）ｒ２２３７．２ｇ ｄ２４．００ ｒ４２８．９６ （Ｌ　　１７．０８ ｒａ　−１２９，０６ Σｄ　＝３６．５．８ ｆ＝１８０ 曲率半径 ｒ、　　３７．２８ ｒ２　１７３．８１ ｒ３−５８６．２３ ｒ４３０．７３ ｒ５１８８．６８ ｒｅ　（３７，５１ 第　　　３　　　表 ＦＮＯ，＝１０．０ 軸上面間隔　　屈折率（Ｎｄ） ｄ、　　７．７０　　　Ｎ、　　１．７８５６４　４．
００ ｄ３２．４０　　　Ｎ２　１．５８４０ｄ４１８．１１ ｄ、　　５．３０　　Ｎ、　　１．４９１４Σｄ＝　３
７．５１ アツベ　数　（νｄ） ν＋　　４２．８ ５７．８ ｆ＝１８０ 曲率半径 ｒｌ　　３８．１９ ｒａ　　１５２．５７ ｒａ　−９０９，８Ｏ ｒ４３１．５６ ｒｓ　　１９８．１０ ｒ６（４２，５４ 第　　　４　　　表 ＦＮＯ，＝１０．０ 軸上面間隔　　屈折率［Ｎｄ） ｄ、　　７．７０　　　Ｎ、　　１．８２０５ｄ２３．
８０ ｄ、　　２．００　　Ｎ２　１．５８４Ｑｄ４１８．４
４ ｄ＠　　５．００　　　Ｎ３　１．４９１４Σｄ＝　３
６．９４ アツベ数　（νｄ） ν＋　　４３．０ ３１．０ ５７．８ 次に、この発明の態様環３のレンズ系である実施例５な
いし実施例９について説明する。これらの例の場合はプ
ラスチックレンズに非球面を使用している例である。(Left below) Table 1 f=180 FNO,=10. 0 Radius of curvature axis upper surface interval Refractive index (Nd) 7-tube number (υd) r
+ 168.75 d23.80 r, 30.36 d418.16 re -13s, 29 Σd =36.66 Second Table f=180 FNO,=10. 0 Radius of curvature Distance between upper surfaces of axis Refractive index (Nd) 7'
・N/(number (1) d) r2237.2g d24.00 r428.96 (L 17.08 ra -129,06 Σd =36.5.8 f=180 Radius of curvature r, 37.28 r2 173.81 r3-586.23 r430.73 r5188.68 re (37,51 Table 3 FNO, = 10.0 Axial distance Refractive index (Nd) d, 7.70 N, 1.78564 4.
00 d32.40 N2 1.5840d418.11 d, 5.30 N, 1.4914Σd= 3
7.51 Atsube number (νd) ν+ 42.8 57.8 f=180 Radius of curvature rl 38.19 ra 152.57 ra -909,8O r431.56 rs 198.10 r6 (42,54 Table 4 FNO, =10.0 Axial surface spacing Refractive index [Nd) d, 7.70 N, 1.8205d23.
80 d, 2.00 N2 1.584Qd418.4
4 d@ 5.00 N3 1.4914Σd= 3
6.94 Atsube number (νd) ν+ 43.0 31.0 57.8 Next, Examples 5 to 9, which are lens systems of Aspect 3 of the present invention, will be described. In these examples, an aspherical surface is used for the plastic lens.

そのレンズ構成を第９図、第１１図、第１３図第１５図
および第１７図に示す。即ち、左側の片側から順に、レ
ンズ系の外側に凸面を向けた正メニスカスレンズの第１
レンズ、凹レンズの第２レンズおよび凸レンズの第３レ
ンズとから構成されている。そして、凹レンズである第
２レンズおよび凸レンズである第３レンズにプラスチッ
クレンズを使用している。第２図レンズには、ポリ力ボ
ネイト、第３レンズにはアクリルを使用している。その
ため、軽量化が可能となり、型成形されるので大量生産
が可能となる。The lens configuration is shown in FIGS. 9, 11, 13, 15, and 17. That is, starting from one side on the left, the first positive meniscus lens has a convex surface facing the outside of the lens system.
It is composed of a second lens, which is a concave lens, and a third lens, which is a convex lens. Plastic lenses are used for the second lens, which is a concave lens, and the third lens, which is a convex lens. Polybonate is used for the lens in Figure 2, and acrylic is used for the third lens. Therefore, it becomes possible to reduce the weight, and since it is molded, mass production becomes possible.

全系の焦点距離をｆ、第１レンズと第２レンズ間の軸上
空気間隔なｄ２．第２レンズと第３レンズ間の軸上空気
間隔なｄ４．第１レンズの焦点距離をｆ＋、第２レンズ
の焦点距離をｆ２．第１レンズの硝材の屈折率およびア
ツベ数をＮ１　　ν１とするとき ■　０．００５ｆ＜ｄ２＜０．０１５ｆ■　０．０５ｆ
＜ｄ４＜０．１５ｆ ■　０．０１５ｆ＜ｆ、＋ｆ２＜０．０５ｆ■　１．６
５＜Ｎ ［相］　３５くν１〈５０ の各条件式を満足させる。The focal length of the entire system is f, the axial air distance between the first lens and the second lens is d2. The axial air distance between the second lens and the third lens d4. The focal length of the first lens is f+, the focal length of the second lens is f2. When the refractive index and Atsube number of the glass material of the first lens are N1 ν1■ 0.005f<d2<0.015f■ 0.05f
<d4<0.15f ■ 0.015f<f, +f2<0.05f■ 1.6
5<N [phase] 35×ν1<50 Each conditional expression is satisfied.

上記条件式〇は、第１レンズと第２レンズ間の軸上空気
間隔を定めるもので、この条件を外れると歪曲収差９倍
率色収差をバランスよく補正することができない。The above conditional expression (0) determines the axial air distance between the first lens and the second lens, and if this condition is violated, distortion and 9x chromatic aberration cannot be corrected in a well-balanced manner.

上記条件式■は、第２レンズと第３レンズ間の軸上空気
間隔を定めるもので、この下限値を越えるとコマフレア
の発生が大きくなって像のコントラストが低下する。ま
た上限値を越えると歪曲収差の補正が十分できない。ま
た、レンズが大型化してしまうので望ましくない。The above conditional expression (2) determines the axial air distance between the second lens and the third lens, and if this lower limit value is exceeded, the occurrence of coma flare increases and the contrast of the image decreases. Furthermore, if the upper limit is exceeded, distortion cannot be sufficiently corrected. Further, the lens becomes large, which is not desirable.

上記条件式■は、第１レンズと第２レンズの焦点距離の
和を定めたもので、主に球面収差を抑えるための条件で
ある。この上限値を越えると球面収差が補正過剰となる
。・また下限値を越えると球面収差が補正不足となると
同時に、非点収差が大きくなり像面が倒れる。The above conditional expression (2) defines the sum of the focal lengths of the first lens and the second lens, and is mainly a condition for suppressing spherical aberration. If this upper limit is exceeded, spherical aberration will be overcorrected. -If the lower limit is exceeded, spherical aberration will be insufficiently corrected, and at the same time, astigmatism will increase and the image plane will collapse.

上記条件式■、［相］は、ともに第１レンズの硝材を定
める条件である。■の条件を外れると非点隔差が増大す
る。また、コマ収差が十分に補正し切れなくなる。The above conditional expression (2) and [phase] are both conditions for determining the glass material of the first lens. If the condition (2) is not met, the astigmatism difference increases. Moreover, coma aberration cannot be sufficiently corrected.

また、上記条件式［相］の条件を外れると、いずれの場
合も十分な色補正ができなくなる。Further, if the above conditional expression [phase] is not satisfied, sufficient color correction will not be possible in any case.

以下、第６表ないし第１０表に、本実施例５ないし実施
例９の曲率半径、軸上面間隔、硝材のｄ線での屈折率お
よびアツベ数の数値をそれぞれ示す。第１０図、第１２
図、第１４図、第１６図および第１８図はそれぞれ実施
例５〜実施例９の一１×時における収差曲線図である。Tables 6 to 10 below show the curvature radius, axial distance, refractive index at the d-line of the glass material, and Abbe's number of Examples 5 to 9, respectively. Figures 10 and 12
14, 16, and 18 are aberration curve diagrams at 1× of Examples 5 to 9, respectively.

各実施例の焦点距離はｆ＝１８０ｍｍ、Ｆ値は１０．半
画角ω＝２２．６°である。また、上記条件式■〜［相
］に対応する実施例５〜９の各個並びにコンパクトさの
指標である全厚Σｄの数値を第１１表に纏めて示す。The focal length of each example is f=180mm, and the F value is 10. The half angle of view ω=22.6°. Further, Table 11 summarizes the values of each of Examples 5 to 9 corresponding to the above conditional expressions (1) to [phase] and the total thickness Σd, which is an index of compactness.

また、本実施例５〜実施例９では第２レンズもしくは第
３レンズに非球面を使用しており、実施例５〜実施例７
では、第２レンズの第３レンズ側の面、実施例８では、
第２レンズの第３レンズ側の面、実施例９では、第２レ
ンズの第３レンズ側の面と第３レンズのレンズ系の外側
の面とがそれぞれ非球面となっており、第６表ないし第
１０表の下欄に非球面係数をそれぞれ示す。In addition, in Examples 5 to 9, an aspherical surface is used for the second lens or the third lens, and Examples 5 to 7
Now, in Example 8, the surface of the second lens on the third lens side,
The surface of the second lens on the third lens side, in Example 9, the surface of the second lens on the third lens side and the surface of the third lens on the outside of the lens system are each aspherical surfaces, as shown in Table 6. The aspheric coefficients are shown in the lower columns of Tables 1 to 10, respectively.

この非球面は、光軸なＸ軸にとり、面頂点Ｘ＝０の平面
内に直交座標ｙ軸、Ｚ軸をとるとき、非球面はｘ＝ｆ　
（ｙ、ｚ）で表される。When taking this aspherical surface as the optical axis, the X-axis, and taking orthogonal coordinates y-axis and Z-axis within the plane of the surface vertex X=0, the aspherical surface is x=f
Represented by (y, z).

ｙ２＋２２＝φ２とおくと で与えられる。非球面係数は上記式中のＡ、の値であり
、ｃｏは曲率半径の逆数である。このような非球面を使
うことにより、収差補正の自由度が増えレンズの全厚を
小さくしても、諸収差を良く補正できる。It is given by setting y2+22=φ2. The aspheric coefficient is the value of A in the above formula, and co is the reciprocal of the radius of curvature. By using such an aspherical surface, the degree of freedom in correcting aberrations increases, and various aberrations can be well corrected even if the total thickness of the lens is reduced.

（以下余白） ×　　　　　× 次に、この発明の態俤項４のレンズ系である実施例１０
ないし実施例１３について説明する。これらの例の場合
もプラスチックレンズに非球面を使用している例である
。(The following is a margin) × × Next, Example 10 which is the lens system of aspect item 4 of this invention
Embodiment 13 will be explained. These examples are also examples in which an aspherical surface is used for the plastic lens.

そのレンズ構成を第】９図、第２１図、第２３図および
第２５図に示す。即ち、左側の物体側から順に、物体側
に凸面を向けた正メニスカスレンズの第１レンズ、凹レ
ンズの第２レンズおよび凸レンズの第３レンズとから構
成されている。そして、凹レンズである第２レンズおよ
び第３レンズにプラスチックレンズを使用している。第
２レンズにはポリカーボネイト、第３レンズにはアクリ
ルを使用している。そのため、軽量化が可能となり、型
成形されるので大量生産が可能となる。The lens configuration is shown in FIGS. 9, 21, 23, and 25. That is, in order from the object side on the left side, it is composed of a first lens that is a positive meniscus lens with a convex surface facing the object side, a second lens that is a concave lens, and a third lens that is a convex lens. Plastic lenses are used for the second and third lenses, which are concave lenses. The second lens is made of polycarbonate, and the third lens is made of acrylic. Therefore, it becomes possible to reduce the weight, and since it is molded, mass production becomes possible.

全系の焦点距離をｆ、第１レンズと第２レンズ間の軸上
空気間隔をｄ２．第２レンズと第３レンズ間の軸上空気
間隔なｄ４．第１レンズの焦点距離なｆｌ、第２レンズ
の焦点距離をｆ２．第１レンズの硝材の屈折率およびア
ツベ数をＮν１．第２レンズの第３レンズ側の面および
第３レンズの第２レンズ側の面の曲率半径をｒ４ｒ５と
するとき ■　０．００５ｆ＜ｄ２＜０．０２５ｆ＠　　０．０５
ｆ＜ｄ４＜０．０８ｆ ９　１．７５＜Ｎ、＜１．８５ ■　３５〈ν１く５０ ■　−０，１＜　　　　　＜０．２５ 上記条件式■は、第１レンズと第２レンズ間の軸上空気
間隔を定めるもので、この条件を外れると歪曲収差１倍
率色収差をバランスよく補正することができない。The focal length of the entire system is f, the axial air distance between the first lens and the second lens is d2. The axial air distance between the second lens and the third lens d4. The focal length of the first lens is fl, the focal length of the second lens is f2. The refractive index and Atsube number of the glass material of the first lens are Nν1. When the radius of curvature of the surface of the second lens on the third lens side and the surface of the third lens on the second lens side is r4r5, ■ 0.005f<d2<[email protected]
f<d4<0.08f 9 1.75<N, <1.85 ■ 35<ν1×50 ■ −0,1<<0.25 The above conditional expression (■) is based on the axis between the first lens and the second lens. This determines the upper air spacing, and if this condition is exceeded, distortion and lateral chromatic aberration cannot be corrected in a well-balanced manner.

上記条件式＠は、第２レンズと第３レンズ間の軸上空気
間隔を定めるもので、この下限値を越えるとコマフレア
の発生が大きくなって像のコントラストが低下する。ま
た上限値を越えると歪曲収差の補正が十分てきない。ま
た、レンズが大型化してしまうので望ましくない。The above conditional expression @ determines the axial air distance between the second lens and the third lens, and if this lower limit value is exceeded, the occurrence of coma flare increases and the contrast of the image decreases. Furthermore, if the upper limit is exceeded, distortion cannot be sufficiently corrected. Further, the lens becomes large, which is not desirable.

上記条件式０．■は、ともに第１レンズの硝材を定める
条件である。■の条件を外れると非点隔差が増大する。The above conditional expression 0. (2) are both conditions that determine the glass material of the first lens. If the condition (2) is not met, the astigmatism difference increases.

また、コマ収差が十分に補正し切れなくなる。Furthermore, coma aberration cannot be sufficiently corrected.

また、上記条件式■の条件を外れると、いずれの場合も
十分な色補正ができな（なる。Furthermore, if the above conditional expression (2) is not satisfied, sufficient color correction will not be possible in any case.

上記条件式■は、第２レンズと第３レンズの隣接する曲
率半径の比で、コマ収差および球面収差を補正するだめ
の条件である。上限値を越えるとコマ収差の発生が大き
くなる。また、球面収差は補正不足となり、像のコント
ラストが低下する。The above conditional expression (2) is the ratio of the adjacent radii of curvature of the second lens and the third lens, and is a condition for correcting comatic aberration and spherical aberration. If the upper limit is exceeded, coma aberration will increase. Furthermore, spherical aberration is insufficiently corrected, and the contrast of the image is reduced.

また、下限値を越えると球面収差は補正過剰になる。更
に像面性が悪くなり、周辺部での性能が悪化する。Moreover, when the lower limit is exceeded, spherical aberration becomes overcorrected. Furthermore, the image surface properties deteriorate, and the performance in the peripheral area deteriorates.

また、実施例１０〜１３では、第１レンズの焦点距離を
ｆｌ、第２レンズの焦点距離をｆ２とすると、 ０、　０３ｆ＜ｆｌ　　＋ｆ２　　＜０　　１　ｆを満
足している。Furthermore, in Examples 10 to 13, the following relationship is satisfied, where the focal length of the first lens is fl and the focal length of the second lens is f2.

これは、第１レンズと第２レンズの焦点距離の和を定め
るもので、主に球面収差を抑えるための条件である。こ
の」二限値を越えると球面収差が補正過剰となる。また
、下減価を下回ると球面収差が補正不足になると同時に
非点収差が太き（なり像面が倒れる。This determines the sum of the focal lengths of the first lens and the second lens, and is mainly a condition for suppressing spherical aberration. When this two-limit value is exceeded, spherical aberration becomes overcorrected. Furthermore, when the value falls below the lower depreciation value, spherical aberration becomes insufficiently corrected, and at the same time, astigmatism becomes thicker (and the image plane is tilted).

以下、第１２表ないし第１５表に、本実施例１０ないし
実施例１３の曲率半径、軸上面間隔硝材のｄ線での屈折
率およびアツベ数の数値をそれぞれ示す。第２０図、第
２２図、第２４図および第２６図はそれぞれ実施例１０
〜実施例１３の＝１×時における収差曲線図である。Tables 12 to 15 show the radius of curvature, the refractive index at the d-line of the axial distance glass material, and the Abbe number of Examples 10 to 13, respectively. FIGS. 20, 22, 24, and 26 are Example 10, respectively.
~ FIG. 13 is an aberration curve diagram when =1× in Example 13.

各実施例の焦点距離はｆ＝１８０ｍｍ、Ｆ値は１０、半
画角ω＝２２．６°である。また、上記条件式■〜［相
］に対応する実施例１０〜実施例１３の各個並びにコン
パクトさの指標である全厚Σｄの数値を第１６表に纏め
て示す。The focal length of each example is f=180 mm, the F value is 10, and the half angle of view ω=22.6°. Further, Table 16 summarizes the numerical values of Examples 10 to 13 corresponding to the above conditional expressions (1) to [phase] and the total thickness Σd, which is an index of compactness.

また、本実施例１０〜実施例１３では、第２レンズの第
３レンズ側の面ｒ４と第３レンズのレンズ系の外側の面
ｒ６とに非球面を用いており、第１２表ないし第１５表
の下欄に非球面係数をそれぞれ示す。Furthermore, in Examples 10 to 13, aspherical surfaces are used for the surface r4 of the second lens on the third lens side and the surface r6 outside the lens system of the third lens. The aspheric coefficients are shown in the bottom column of the table.

この非球面は、光軸をＸ軸にとり、面頂点Ｘ＝０の平面
内に直交座標ｙ軸、Ｚ軸をとるとき、非球面はｘ　＝　
ｆ　（ｙ　＋　ｚ　）で表される。This aspherical surface has an optical axis as the
It is expressed as f (y + z).

ｙ２　＋２２　＝＝φ２とおくと で与えられる。非球面係数は上記式中のＡＩの値であり
、Ｃ０は曲率半径の逆数である。このような非球面を使
うことにより、収差補正の自由度が増えレンズ全厚を小
さくしても諸収差を補正できる。It is given by setting y2 +22 ==φ2. The aspheric coefficient is the value of AI in the above formula, and C0 is the reciprocal of the radius of curvature. By using such an aspheric surface, the degree of freedom in correcting aberrations increases, and various aberrations can be corrected even if the total lens thickness is reduced.

（以下余白） ×　　×　× ｃ；　ｃｉ　６　ｃｈ６゜ てくく七＜く 豐　　　　°品 ×　　　　× ６　ｃ＝；　ｏＯｃ＝；　ｃ＝ｉ ×　　　　　× この発明の複写装置用レンズ系は、３枚構成のレンズ系
でレンズ枚数が少なく、また、その１枚のレンズをプラ
スチックレンズで構成し大幅なコストダウンと軽量化を
もたらし、かつ、従来の４枚構成レンズ系ではレンズ全
厚が０．２ｆが限界であったが、この発明のレンズ系で
は０１５ｆ〜０．２１ｆと著しく短く、コンパクトなレ
ンズ系となっており、複写装置全体の小型化に寄与する
ことができる。そして、レンズ性能においても従来レン
ズと同等かそれ以上である。(The following is a margin) The system has a small number of lenses, and one lens is made of a plastic lens, resulting in significant cost and weight reductions.In addition, the total lens thickness of conventional 4-element lens systems is limited to 0.2 f. However, the lens system of the present invention has a significantly short and compact lens system of 0.15f to 0.21f, and can contribute to miniaturization of the entire copying apparatus. In addition, the lens performance is equal to or better than conventional lenses.

なお、本実施例１ないし１３には、−１×時つまり等倍
時の収差状況を示したが、等倍においては、物体面と像
面とを入れ替えても各収差の発生量は、歪曲の符号を除
いて全く同じであるので、このレンズ系の物体面側と像
面側とを逆にしてもよい。In addition, in Examples 1 to 13, the aberration situation at -1x, that is, at the same magnification, is shown, but at the same magnification, even if the object plane and the image plane are exchanged, the amount of each aberration generated will be the same as the distortion. Since they are exactly the same except for the signs, the object plane side and image plane side of this lens system may be reversed.

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

第１図は、この発明の実施例１のレンズ構成を示す断面
図、 第２図は、上記第１図に示すレンズ系の収差曲線図、 第３図は、この発明の実施例２のレンズ構成を示す断面
図、 第４図は、上記第３図に示すレンズ系の収差曲線図、 第５図は、この発明の実施例３のレンズ構成を示す断面
図、 第６図は、上記第５図に示すレンズ系の収差曲線図、 第７図は、この発明の実施例４のレンズ構成を示す断面
図、 第８図は、上記第７図に示すレンズ系の収差曲線図、 第９図は、この発明の実施例５のレンズ構成を示す断面
図、 第１０図は、上記第９図に示すレンズ系の収差曲線図、 第１１図は、この発明の実施例６のレンズ構成を示す断
面図、 第１２図は、上記第１１′図に示すレンズ系の収左曲線
図、 第１３図は、この発明の実施例７のレンズ構成を示す断
面図、 第１４図は、上記第１３図に示すレンズ系の収差曲線図
、 第１５図は、この発明の実施例８のレンズ構成を示す断
面図、 第１６図は、上記第１５図に示すレンズ系の収差曲線図
、 第１７図は、この発明の実施例９のレンズ構成を示す断
面図、 第１８図は、上記第１７図に示すレンズ系の収差曲線図
、 第１９図は、この発明の実施例１０のレンズ構成を示す
断面図、 第２０図は、上記第１９図に示すレンズ系の収差曲線図
、 第２１図は、この発明の実施例１１のレンズ構成を示す
断面図、 第２２図は、上記第２１図に示すレンズ系の収差曲線図
、 第２３図は、この発明の実施例１２のレンズ構成を示す
断面図、 第２４図は、上記第２３図に示すレンズ系の収差曲線図
、 第２５図は、この発明の実施例１３のレンズ構成を示す
断面図、 第２６図は、上記第２５図に示すレンズ系の収差曲線図
である。 特　許　出　願　人　ミノルタカメラ株式会社代　　　
理　　　人　小　山　１）　　光　夫り０ ■ ひ０ メFIG. 1 is a sectional view showing the lens configuration of Example 1 of the present invention, FIG. 2 is an aberration curve diagram of the lens system shown in FIG. 1, and FIG. 3 is a lens of Example 2 of the invention. 4 is an aberration curve diagram of the lens system shown in FIG. 3 above. FIG. 5 is a sectional view showing the lens structure of Example 3 of the present invention. FIG. 6 is a sectional view showing the lens system shown in FIG. 5 is an aberration curve diagram of the lens system shown in FIG. 5; FIG. 7 is a sectional view showing the lens configuration of Example 4 of the present invention; FIG. The figure is a sectional view showing the lens configuration of Example 5 of the present invention, Figure 10 is an aberration curve diagram of the lens system shown in Figure 9 above, and Figure 11 is the lens configuration of Example 6 of the present invention. 12 is a convergence curve diagram of the lens system shown in FIG. 11', FIG. 13 is a sectional view showing the lens configuration of Example 7 of the present invention, and FIG. 13 is an aberration curve diagram of the lens system shown in FIG. 13, FIG. 15 is a sectional view showing the lens configuration of Example 8 of the present invention, FIG. 16 is an aberration curve diagram of the lens system shown in FIG. The figure is a sectional view showing the lens configuration of Example 9 of the present invention, Figure 18 is an aberration curve diagram of the lens system shown in Figure 17 above, and Figure 19 is the lens configuration of Example 10 of the present invention. 20 is an aberration curve diagram of the lens system shown in FIG. 19, FIG. 21 is a sectional view showing the lens configuration of Example 11 of the present invention, and FIG. 22 is the diagram shown in FIG. FIG. 23 is a sectional view showing the lens configuration of Example 12 of the present invention. FIG. 24 is an aberration curve diagram of the lens system shown in FIG. 23. FIG. 25 is an aberration curve diagram of the lens system shown in FIG. FIG. 26 is an aberration curve diagram of the lens system shown in FIG. 25. Patent applicant: Minolta Camera Co., Ltd.
Rihito Koyama 1) Light husbandri0 ■ Hi0me

Claims (5)

【特許請求の範囲】[Claims] （１）片側から順に、レンズ系の外側に凸面を向けた正
メニスカスレンズの第１レンズと、負のパワーをもつ第
２レンズと、正のパワーをもつ第３レンズとからなり、
第２レンズと第３レンズにプラスチックを使用すること
を特徴とする複写装置用レンズ系。(1) Consisting of, in order from one side, a first lens that is a positive meniscus lens with a convex surface facing the outside of the lens system, a second lens with negative power, and a third lens with positive power,
A lens system for a copying device, characterized in that a second lens and a third lens are made of plastic. （２）次の各条件式を満足する請求項１記載の複写装置
用レンズ系。 ［１］０．０１５ｆ＜ｄ＿２＜０．０２５ｆ ［２］０．０５ｆ＜ｄ＿４＜０．１５ｆ ［３］０．０４ｆ＜ｆ＿１＋ｆ＿２＜０．０６ｆ ［４］１．６５＜Ｎ＿１ ［５］３５＜υ＿１＜５０ ただし、ｆ；全系の焦点距離 ｄ＿２；第１レンズと第２レンズの間の 軸上空気間隔 ｄ＿４；第２レンズと第３レンズの間の 軸上空気間隔 ｆ＿１；第１レンズの焦点距離 ｆ＿２；第２レンズの焦点距離 Ｎ＿１；第１レンズの硝材のｄ線での屈 折率 ν＿１；第１レンズの硝材のアッベ数(2) A lens system for a copying machine according to claim 1, which satisfies each of the following conditional expressions. [1] 0.015f<d_2<0.025f [2] 0.05f<d_4<0.15f [3] 0.04f<f_1+f_2<0.06f [4] 1.65<N_1 [5] 35<υ_1 <50 However, f; focal length of the entire system d_2; axial air distance between the first and second lenses d_4; axial air distance between the second and third lenses f_1; focal point of the first lens Distance f_2; Focal length of the second lens N_1; Refractive index ν_1 of the glass material of the first lens at the d-line; Abbe number of the glass material of the first lens （３）第２レンズと第３レンズの少なくとも１面を非球
面とした請求項１記載の複写装置用レンズ系。(3) The lens system for a copying machine according to claim 1, wherein at least one surface of the second lens and the third lens is an aspherical surface. （４）次の各条件式を満足する請求項１記載の複写装置
用レンズ系。 ［６］０．００５ｆ＜ｄ＿２＜０．０１５ｆ［７］０．
０５ｆ＜ｄ＿４＜０．１５ｆ ［８］０．０１５ｆ＜ｆ＿１＋ｆ＿２＜０．０５ｆ［９
］１．６５＜Ｎ＿１ ［１０］３５＜ν＿１＜５０ ただし、ｆ；全系の焦点距離 ｄ＿２；第１レンズと第２レンズの間の 軸上空気間隔 ｄ＿４；第２レンズと第３レンズの間の 軸上空気間隔 ｆ＿１；第１レンズの焦点距離 ｆ＿２；第２レンズの焦点距離 Ｎ＿１；第１レンズの硝材のｄ線での屈 折率 ν＿１；第１レンズの硝材のアッベ数(4) A lens system for a copying machine according to claim 1, which satisfies each of the following conditional expressions. [6] 0.005f<d_2<0.015f[7]0.
05f<d_4<0.15f [8] 0.015f<f_1+f_2<0.05f[9
]1.65<N_1 [10] 35<ν_1<50 where f; focal length of the entire system d_2; axial air distance between the first and second lenses d_4; between the second and third lenses On-axis air distance f_1; focal length of the first lens f_2; focal length of the second lens N_1; refractive index ν_1 of the glass material of the first lens at the d-line; Abbe number of the glass material of the first lens （５）次の各条件式を満足する請求項１記載の複写装置
用レンズ系。 ［１１］０．００５ｆ＜ｄ＿２＜０．０２５ｆ［１２］
０．０５ｆ＜ｄ＿４＜００８ｆ ［１３］１．７５＜Ｎ＿１＜１．８５ ［１４］３５＜ν＿１＜５０ ［１５］−０．１＜（ｒ＿４／ｒ＿５）＜０．２５ただ
し、ｆ；全系の焦点距離 ｄ＿２；第１レンズと第２レンズの間の 軸上空気間隔 ｄ＿４；第２レンズと第３レンズの間の 軸上空気間隔 Ｎ＿１；第１レンズの硝材のｄ線での屈 折率 ν＿１；第１レンズの硝材のアッベ数 ｒ＿４；第２レンズの第３レンズ側の面 の曲率半径 ｒ＿５；第３レンズの第２レンズの側の 面の曲率半径(5) A lens system for a copying machine according to claim 1, which satisfies each of the following conditional expressions. [11] 0.005f<d_2<0.025f[12]
0.05f<d_4<008f [13] 1.75<N_1<1.85 [14] 35<ν_1<50 [15] −0.1<(r_4/r_5)<0.25 However, f; whole system focal length d_2; axial air distance d_4 between the first lens and second lens; axial air distance N_1 between the second lens and third lens; refractive index ν_1 at the d-line of the glass material of the first lens. ; Abbe number of the glass material of the first lens r_4; radius of curvature of the surface of the second lens on the third lens side r_5; radius of curvature of the surface of the third lens on the second lens side
JP1080119A 1989-03-28 1989-03-29 Lens system for copier Expired - Lifetime JP2867413B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP1080119A JP2867413B2 (en) 1989-03-29 1989-03-29 Lens system for copier
US07/794,355 US5204780A (en) 1989-03-28 1991-11-12 Lens system for a copying machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1080119A JP2867413B2 (en) 1989-03-29 1989-03-29 Lens system for copier

Publications (2)

Publication Number Publication Date
JPH02257113A true JPH02257113A (en) 1990-10-17
JP2867413B2 JP2867413B2 (en) 1999-03-08

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JP1080119A Expired - Lifetime JP2867413B2 (en) 1989-03-28 1989-03-29 Lens system for copier

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5300412A (en) * 1991-03-01 1994-04-05 Fuji Photo Film Co., Ltd. Silver halide color photographic material
JP2006525555A (en) * 2003-05-01 2006-11-09 レイセオン・カンパニー Compact wide-field imaging optical system
JP2017526953A (en) * 2014-08-07 2017-09-14 ハンズ レーザー テクノロジー インダストリー グループ カンパニー リミテッド Far-infrared imaging lens set, objective lens, and fire source detector

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01261613A (en) * 1988-04-13 1989-10-18 Konica Corp Triplet lens

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01261613A (en) * 1988-04-13 1989-10-18 Konica Corp Triplet lens

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5300412A (en) * 1991-03-01 1994-04-05 Fuji Photo Film Co., Ltd. Silver halide color photographic material
JP2006525555A (en) * 2003-05-01 2006-11-09 レイセオン・カンパニー Compact wide-field imaging optical system
JP2017526953A (en) * 2014-08-07 2017-09-14 ハンズ レーザー テクノロジー インダストリー グループ カンパニー リミテッド Far-infrared imaging lens set, objective lens, and fire source detector

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