JP2806056B2 - Real image type variable magnification finder optical system - Google Patents
Real image type variable magnification finder optical systemInfo
- Publication number
- JP2806056B2 JP2806056B2 JP3033664A JP3366491A JP2806056B2 JP 2806056 B2 JP2806056 B2 JP 2806056B2 JP 3033664 A JP3033664 A JP 3033664A JP 3366491 A JP3366491 A JP 3366491A JP 2806056 B2 JP2806056 B2 JP 2806056B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- finder
- positive
- object side
- erector system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Viewfinders (AREA)
- Lenses (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は実像式変倍ファインダー
光学系に関し、特に撮影系とは別体に設けた外部式のフ
ァインダー光学系のレンズ構成を適切に設定し、種々の
倍率でファインダー像の良好なる観察を可能とした例え
ばスチルカメラやビデオカメラ等に好適な実像式変倍フ
ァインダー光学系に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a real image type variable magnification finder optical system, and more particularly to an external finder optical system which is provided separately from a photographing system by appropriately setting the lens configuration of the finder image system at various magnifications. The present invention relates to a real-image variable-magnification finder optical system suitable for, for example, a still camera or a video camera capable of excellent observation.
【０００２】[0002]
【従来の技術】従来より撮影系とファインダー光学系が
別体に構成されているカメラでは撮影系が変倍系のとき
には変倍に伴いファインダー視野倍率が変化する構成の
変倍ファインダーが撮影上好ましい。又、変倍ファイン
ダーはカメラに組込むことから小型でしかも所定の変倍
比が容易に得られる構成のものが好ましい。2. Description of the Related Art Conventionally, in a camera in which a photographing system and a finder optical system are configured separately, when a photographing system is a variable magnification system, a variable magnification finder having a configuration in which a finder field magnification changes with magnification is preferable for photographing. . In addition, since the variable magnification finder is incorporated in a camera, it is preferable that the variable magnification finder has a configuration that is small and can easily obtain a predetermined magnification ratio.
【０００３】このような撮影系と別体に構成された外部
式のファインダー光学系はＴＴＬ方式のファインダー光
学系に比べファインダー系全体を小型化出来る。しかも
ファインダー光学系のレンズ構成を比較的容易に構成す
ることができる等の利点が多い為近年種々と提案されて
おり、又スチルカメラやビデオカメラ等に多く用いられ
ている。An external finder optical system formed separately from such a photographing system can reduce the size of the entire finder system as compared with a TTL finder optical system. Moreover, there are many advantages such as the lens configuration of the viewfinder optical system can be relatively easily configured, and various proposals have been made in recent years, and they are widely used in still cameras and video cameras.
【０００４】この実像式変倍ファインダー光学系の１つ
として対物レンズを多群のレンズ群で構成し変倍の際、
各レンズ群の空気間隔を変化させることによって変倍を
行う正立正像用のポロプリズムを用いた実像式変倍ファ
インダー光学系が例えば特開昭６１−１５６０１９号公
報で提案されている。[0004] As one of the real image type variable magnification finder optical systems, an objective lens is composed of a plurality of lens groups.
A real image type variable magnification finder optical system using a Porro prism for an erect erect image, which performs magnification by changing the air spacing of each lens group, has been proposed in, for example, Japanese Patent Application Laid-Open No. 156019/1986.
【０００５】又、対物レンズを構成するレンズ群の一部
を変倍の際、移動させると同時にエレクター系を構成す
るレンズ群の一部も対物レンズの移動量と同じ移動量だ
け移動させることによって変倍を行う実像式変倍ファイ
ンダー光学系が例えば特公昭４７−１９１２号公報で提
案されている。[0005] Further, by moving a part of the lens group constituting the objective lens at the time of zooming, simultaneously moving a part of the lens group constituting the erector system by the same moving amount as the moving amount of the objective lens. A real image type variable magnification finder optical system for performing variable magnification is proposed in, for example, Japanese Patent Publication No. 47-1912.
【０００６】又、本出願人は対物レンズを一体的に移動
させると共にエレクター系を対物レンズとは異なる量だ
け移動させて変倍を行なった変倍比３〜４程度の変倍フ
ァインダー光学系を特開平２−９６１０８号公報で提案
している。Further, the present applicant has developed a variable magnification finder optical system having a variable magnification ratio of about 3 to 4 in which the objective lens is moved integrally and the erector system is moved by an amount different from that of the objective lens. This is proposed in Japanese Patent Application Laid-Open No. 2-96108.
【０００７】[0007]
【発明が解決しようとする課題】前述した特開昭６１−
１５６０１９号公報で提案されている実像式変倍ファイ
ンダー光学系は対物レンズで変倍を行う場合、対物レン
ズを構成する各レンズ群の移動量をある程度、制限条件
を加えて構成しようとすると、対物レンズが全体的に大
型化しかつレンズ全長が極めて長くなってくるという問
題点があった。Problems to be Solved by the Invention
In the real image type variable magnification finder optical system proposed in Japanese Patent No. 156019, when performing magnification with an objective lens, if an attempt is made to configure the movement amount of each lens group constituting the objective lens to some extent with a limited condition added thereto, There has been a problem that the lens becomes larger as a whole and the overall length of the lens becomes extremely long.
【０００８】又、前述の特公昭４７−１９１２号公報で
提案されている実像式変倍ファインダー光学系では変倍
用のレンズ群の移動量を、あまり大きくすることができ
ず、この結果変倍比を大きくするのが難しく、又変倍比
が大きくなってくると変倍中ファインダー視度を一定に
保つことが困難となってくるといった問題点があった。In the real image type variable magnification finder optical system proposed in the above-mentioned Japanese Patent Publication No. 47-1912, the amount of movement of the lens group for variable power cannot be increased so much. There is a problem that it is difficult to increase the zoom ratio, and it becomes difficult to keep the finder diopter constant during zooming as the zoom ratio increases.
【０００９】本発明は本出願人が先に特開平２−９６１
０８号公報で提案した実像式変倍ファインダー光学系を
改良し、特にエレクター系のレンズ構成を適切に設定す
ることにより、少ないレンズ枚数でありながら変倍比
３．３程度と高変倍比を有し、かつ高倍率でありながら
比較的レンズ全長が短かく、しかも簡易な構成で低コス
トでありながら諸収差を良好に補正した高い光学性能を
有した例えばスチルカメラやビデオカメラ等に好適な実
像式変倍ファインダー光学系の提供を目的とする。The present invention has been disclosed by the present applicant in Japanese Patent Application Laid-Open No. 2-961.
No. 08 / 080,849, by improving the real image type variable magnification finder optical system, and particularly by appropriately setting the lens configuration of the erector system, it is possible to achieve a high variable magnification ratio of about 3.3 even with a small number of lenses. Suitable for a still camera, a video camera, or the like, which has a high optical performance with good correction of various aberrations while having a relatively short overall lens length while having a high magnification and having a simple configuration and a low cost. An object of the present invention is to provide a real image type variable magnification finder optical system.
【００１０】[0010]
【課題を解決するための手段】本発明の実像式変倍ファ
インダー光学系は、対物レンズによって結像させた第１
ファインダー像をエレクター系により所定面上に第２フ
ァインダー像として再結像させ、該第２ファインダー像
を接眼レンズを介して観察する際、該対物レンズと該エ
レクター系を光軸上各々異った量だけ移動させて変倍を
行うと共に、該エレクター系を物体側から順に両レンズ
面が凸面の正の第１レンズ、物体側に強い屈折面を有し
た正の第２レンズ、物体側に凸面を向けたメニスカス状
の負の第３レンズ、そして物体側に凸面を向けたメニス
カス状の正の第４レンズの４つのレンズより構成し、第
ｉ番目のレンズ面の曲率半径をＲＥｉ、該エレクター系
中の正レンズと負レンズの材質のアッベ数の平均値を各
々νP ，νN 、該エレクター系の望遠側での結像倍率を
βＴ、該エレクター系の焦点距離をｆとしたとき ０．２＜ ＲＥ６／ｆ ＜０．４ ‥‥‥‥‥（１） ０．３＜ ＲＥ７／ｆ ＜０．５ ‥‥‥‥‥（２） ２．５＜ −βＴ ＜４．５ ‥‥‥‥‥（３） ２３ ＜ νN ＜２８ ‥‥‥‥‥（４） ６０ ＜ νP ＜７５ ‥‥‥‥‥（５） なる条件を満足することを特徴としている。A real image type variable magnification finder optical system according to the present invention comprises a first image formed by an objective lens.
When the finder image is re-imaged as a second finder image on a predetermined surface by an erector system, and when the second finder image is observed through an eyepiece, the objective lens and the erector system are different on the optical axis. The zoom lens is moved by an amount to change the magnification, and the erector system is sequentially arranged from the object side in order from the object side, a positive first lens having both convex surfaces, a positive second lens having a strong refractive surface on the object side, and a convex surface facing the object side. And a fourth meniscus-shaped positive meniscus lens having a convex surface facing the object side, wherein the radius of curvature of the i-th lens surface is REi. When the average values of the Abbe numbers of the materials of the positive lens and the negative lens in the system are ν P and ν N , the imaging magnification on the telephoto side of the erector system is βT, and the focal length of the erector system is f. .2 <RE6 / f <0 4 ‥‥‥‥‥ (1) 0.3 <RE7 / f <0.5 ‥‥‥‥‥ (2) 2.5 <-βT <4.5 ‥‥‥‥‥ (3) 23 <ν N <28 特 徴 (4) 60 <ν P <75 ‥‥‥‥‥ (5)
【００１１】[0011]
【実施例】図１、図２は各々本発明の数値実施例１，２
のレンズ断面図である。図３〜図５は本発明の数値実施
例１の広角端、中間、望遠端のズーム位置における諸収
差図、図６〜図８は本発明の数値実施例２の広角端、中
間、望遠端のズーム位置における諸収差図である。1 and 2 show numerical embodiments 1 and 2, respectively, of the present invention.
It is a lens sectional view of. 3 to 5 are graphs showing various aberrations at the wide-angle end, middle, and telephoto end of the zoom lens according to Numerical Embodiment 1 of the present invention. FIGS. 6 to 8 are wide-angle end, middle, and telephoto end of Numerical Embodiment 2 of the present invention. FIG. 7 is a diagram illustrating various aberrations at the zoom position of FIG.
【００１２】図１、図２において（Ａ）は広角端、
（Ｂ）は中間、（Ｃ）は望遠端のズーム位置を示してい
る。図１、図２において１は対物レンズであり、第１結
像面１ｃに実像の第１ファインダー像を形成する前方レ
ンズ群１ａと第１ファインダー像に基づく光束を後述す
るエレクター系２に導光する第１フィールドレンズ１ｂ
とを有している。1A and 1B, (A) is a wide-angle end,
(B) shows the middle position, and (C) shows the zoom position at the telephoto end. 1 and 2, reference numeral 1 denotes an objective lens, which guides a light beam based on the first finder image and a front lens group 1a for forming a first finder image of a real image on a first imaging surface 1c to an erector system 2 described later. First field lens 1b
And
【００１３】２はエレクター系であり、第１結像面１ｃ
に形成した第１ファインダー像を固定の第２結像面３ａ
に実像の第２ファインダー像して再結像させている。Reference numeral 2 denotes an erector system, and a first imaging surface 1c
The first finder image formed on the second fixed imaging surface 3a
Then, a real image is re-imaged as a second finder image.
【００１４】３は第２フィールドレンズであり、２つの
正レンズより成り、その中間に第２結像面３ａが位置す
るようにしている。第２フィールドレンズ３は第２結像
面３ａに形成した第２ファインダー像に基づく光束を接
眼レンズ４に導光している。Reference numeral 3 denotes a second field lens, which is composed of two positive lenses, and the second image plane 3a is located between them. The second field lens 3 guides a light beam based on the second finder image formed on the second image plane 3a to the eyepiece lens 4.
【００１５】５はアイポイントであり、この位置より接
眼レンズ４を介して第２結像面３ａに形成した第２ファ
インダー像を観察している。Reference numeral 5 denotes an eye point from which the second finder image formed on the second imaging surface 3a is observed via the eyepiece lens 4.
【００１６】本実施例では対物レンズ１とエレクター系
２を矢印の如く物体側へ互いに異なった量だけ移動させ
て固定の第２結像面３ａに第２ファインダー像を倍率を
変えて形成し、これにより広角端から望遠端への変倍を
行なっている。In this embodiment, the objective lens 1 and the erector system 2 are moved toward the object side by different amounts as indicated by arrows to form a second finder image on the fixed second imaging surface 3a at different magnifications. Thereby, the magnification is changed from the wide-angle end to the telephoto end.
【００１７】又、エレクター系を前述の如く所定形状の
４つのレンズより構成することにより、変倍に伴なう収
差変動を良好に補正し、全変倍範囲にわたり高い光学性
能を得ている。Further, by constructing the erector system from four lenses having a predetermined shape as described above, aberration fluctuations accompanying zooming can be corrected well, and high optical performance can be obtained over the entire zoom range.
【００１８】即ち、本実施例においては不図示の被写体
からの光束を対物レンズ１の前方レンズ群１ａにより集
光し、第１次結像面１ｃに倒立の第１ファインダー像を
結像している。そして第１次結像面１ｃに結像した第１
ファインダー像に基づく光束を第１フィールドレンズ１
ｂを介してエレクター系２と第２フィールドレンズ３の
一部を介し、第２次結像面３ａに正立正像の第２ファイ
ンダー像を再結像している。そして接眼レンズ４を介し
て第２次結像面３ａ上に形成した第２ファインダー像を
アイポイント５から観察している。That is, in the present embodiment, a light beam from a subject (not shown) is condensed by the front lens group 1a of the objective lens 1, and an inverted first finder image is formed on the primary imaging surface 1c. I have. Then, the first image formed on the primary image forming surface 1c is formed.
The luminous flux based on the finder image is transmitted to the first field lens 1
The second finder image of the erect erect image is re-imaged on the secondary image-forming surface 3a via the erector system 2 and a part of the second field lens 3 via b. Then, a second finder image formed on the secondary imaging surface 3 a via the eyepiece 4 is observed from the eye point 5.
【００１９】そして広角端から望遠端への変倍を行う際
には対物レンズ１を同図に示す矢印の如く物体側へ移動
させる。そしてそれに伴ってエレクター系２を対物レン
ズ１により第１次結像面３ａ上に形成した倒立の第１フ
ァインダー像を固定の第２次結像面３ａ上に再結像させ
るように矢印の如く対物レンズ１とは異なった量だけ物
体側に移動させている。そして第２次結像面３ａ上に再
結像させた正立正像の第２ファインダー像を接眼レンズ
４を介してアイポイント５から所定の倍率で観察してい
る。When changing the magnification from the wide-angle end to the telephoto end, the objective lens 1 is moved to the object side as shown by the arrow in FIG. Then, as shown by an arrow, the inverted first finder image formed on the primary imaging surface 3a by the objective lens 1 of the erector system 2 is re-imaged on the fixed secondary imaging surface 3a. It is moved to the object side by an amount different from that of the objective lens 1. Then, the second finder image of the erect erect image re-formed on the secondary imaging surface 3a is observed from the eye point 5 through the eyepiece lens 4 at a predetermined magnification.
【００２０】この様に構成することにより本実施例では
エレクター系２の近軸横倍率の変化に応じてファインダ
ー倍率を変化させている。With this configuration, in this embodiment, the finder magnification is changed in accordance with the change in the paraxial lateral magnification of the erector system 2.
【００２１】特に本実施例においてはエレクター系２を
前述の如く所定形状のガラス材より成る４つのレンズか
ら構成すると共に前述の条件式を満足するように構成す
ることにより変倍に伴なう収差変動を良好に補正してい
る。特にガラス材より構成し、温度変化等の環境変化に
伴なう屈折率の変動を少なくして、これにより視度変動
を少なくしている。In particular, in the present embodiment, the erector system 2 is made up of four lenses made of a glass material having a predetermined shape as described above, and is constructed so as to satisfy the above-mentioned conditional expression. Fluctuations are well corrected. In particular, it is made of a glass material to reduce a change in the refractive index due to an environmental change such as a temperature change, thereby reducing a diopter change.
【００２２】次にエレクター系に関する前述の各条件式
の技術的意味について説明する。Next, the technical meaning of each of the above-mentioned conditional expressions relating to the erector system will be described.
【００２３】条件式（１）は第３レンズのアイポイント
側（像面側）のレンズ面の曲率半径に関し、主に像面湾
曲を良好に補正する為のものである。条件式（１）の上
限値を越えて屈折力が弱くなりすぎると像面湾曲が増大
し、又下限値を越えて屈折力が強くなりすぎると製造誤
差による収差変動が大きくなってくるので良くない。Conditional expression (1) relates to the radius of curvature of the lens surface on the eye point side (image surface side) of the third lens, and is mainly for favorably correcting field curvature. If the refractive power is too weak beyond the upper limit of conditional expression (1), the curvature of field will increase. If the refractive power is too strong beyond the lower limit, aberration fluctuations due to manufacturing errors will increase. Absent.
【００２４】条件式（２）は第４レンズの物体側のレン
ズ面の曲率半径に関し、主にコマ収差を良好に補正する
為のものである。条件式（２）の上限値を越えて屈折力
が弱くなりすぎるとコマ収差が多く発生し、又下限値を
越えて屈折力が強くなりすぎると面精度等の製造誤差が
厳しくなってくるので良くない。Conditional expression (2) relates to the radius of curvature of the object-side lens surface of the fourth lens, and is mainly for favorably correcting coma. If the refractive power is too weak beyond the upper limit of conditional expression (2), a lot of coma will occur, and if the refractive power is too strong beyond the lower limit, manufacturing errors such as surface accuracy will be severe. Not good.
【００２５】条件式（３）はエレクター系の望遠端での
結像倍率を適切に設定し、望遠側での収差補正を良好に
行なう為のものである。条件式（３）の上限値を越えて
結像倍率が大きくなりすぎると望遠側での諸収差をバラ
ンス良く補正するのが難しくなり、又下限値を越えて結
像倍率が小さくなりすぎると所定の変倍比を効果的に得
るのが難しくなってくる。Conditional expression (3) is for appropriately setting the imaging magnification at the telephoto end of the erector system and favorably correcting aberrations on the telephoto side. If the imaging magnification is too large beyond the upper limit of conditional expression (3), it becomes difficult to correct various aberrations on the telephoto side in a well-balanced manner. If the imaging magnification is too small below the lower limit, a predetermined value is obtained. It becomes difficult to obtain the zoom ratio effectively.
【００２６】条件式（４），（５）はエレクター系を構
成する負レンズと正レンズの材質のアッベ数を適切に設
定し、主に変倍に伴なう色収差の変動を良好に補正する
為のものである。条件式（４）の上限値又は条件式
（５）の下限値を越えると変倍に伴なう軸上色収差の変
動が大きくなってくる。条件式（４）の下限値又は条件
式（５）の上限値を越えると製造上、物理的及び化学的
に安定した硝材を得るのが難しくなってくる。The conditional expressions (4) and (5) appropriately set the Abbe numbers of the materials of the negative lens and the positive lens constituting the erector system, and satisfactorily correct the fluctuation of chromatic aberration mainly due to zooming. It is for. If the upper limit of conditional expression (4) or the lower limit of conditional expression (5) is exceeded, the fluctuation of axial chromatic aberration accompanying zooming will increase. If the lower limit of conditional expression (4) or the upper limit of conditional expression (5) is exceeded, it becomes difficult to obtain a physically and chemically stable glass material in production.
【００２７】尚、本実施例では対物レンズ１の物体側に
入射瞳を配置し、対物レンズの前方レンズ群１ａと第１
フィールドレンズ１ｂのレンズ系を共に小型になるよう
にしている。又第１結像面１ｃを第１フィールドレンズ
１ｂから少し離し、第１フィールドレンズのレンズ面に
ゴミや埃等が付着してもファインダー像の観察の際にこ
れらのゴミ等が観察されないようにしている。In this embodiment, the entrance pupil is arranged on the object side of the objective lens 1, and the front lens group 1a of the objective lens and the first
Both the lens systems of the field lens 1b are made compact. Further, the first imaging surface 1c is slightly separated from the first field lens 1b so that even if dust or dirt adheres to the lens surface of the first field lens, the dirt or the like is not observed when observing the finder image. ing.
【００２８】本実施例においては第２フィールドレンズ
３を厚い２枚のレンズより構成し、その間に第２結像面
を位置させ、この位置に視野枠を配置している。これに
より第２結像面にゴミ等が侵入し付着するのを防止し、
空気と接するレンズ面の視度をずらして該レンズ面にゴ
ミ等が付着してもファインダー像の観察の際に、これら
のゴミ等が観察されないようにしている。In the present embodiment, the second field lens 3 is composed of two thick lenses, the second image plane is located between them, and the field frame is arranged at this position. This prevents dust and the like from entering and attaching to the second imaging surface,
Even if dust or the like adheres to the lens surface by shifting the diopter of the lens surface in contact with air, the dust or the like is not observed when the finder image is observed.
【００２９】次に図１、図２に示す各要素の数値実施例
を示す。数値実施例においてＲｉは物体側より順に第ｉ
番目のレンズ面の曲率半径、Ｄｉは物体側より第ｉ番目
のレンズ厚及び空気間隔、Ｎｉとνｉは各々物体側より
順に第ｉ番目のレンズのガラスの屈折率とアッベ数であ
る。Next, numerical examples of each element shown in FIGS. 1 and 2 will be described. In the numerical examples, Ri is the i-th order from the object side.
The radius of curvature of the lens surface, Di is the i-th lens thickness and air gap from the object side, and Ni and νi are the refractive index and Abbe number of the glass of the i-th lens in order from the object side.
【００３０】非球面形状は光軸方向にＸ軸、光軸と垂直
方向にＨ軸、光の進行方向を正としＲを近軸曲率半径、
Ａ，Ｂ，Ｃ，Ｄ，Ｅを各々非球面係数としたとき なる式で表わしている。 数値実施例 １ ファインダー倍率 0.35 〜1.14 2ω= 52.7°〜16.0° R 1= -35.00 D 1= 3.0 N 1=1.49171 ν 1= 57.4 R 2= -9.51 D 2= 0.5 R 3= 22.00 D 3= 3.5 N 2=1.60311 ν 2= 60.7 R 4= -17.85 D 4= 12.8 R 5= 11.89 D 5= 3.0 N 3=1.49171 ν 3= 57.4 R 6= 103.40 D 6= 可変 R 7= 26.28 D 7= 2.8 N 4=1.48749 ν 4= 70.2 R 8= -31.83 D 8= 0.5 R 9= 11.51 D 9= 2.8 N 5=1.48749 ν 5= 70.2 R10= 55.88 D10= 1.3 R11= 10.20 D11= 1.5 N 6=1.84666 ν 6= 23.9 R12= 5.60 D12= 1.5 R13= 6.62 D13= 2.5 N 7=1.51633 ν 7= 64.1 R14= 10.50 D14= 可変 R15= 20.43 D15= 5.0 N 8=1.49171 ν 8= 57.4 R16= ∞ D16= 0.2 R17= ∞ D17= 5.0 N 9=1.49171 ν 9= 57.4 R18= -50.00 D18= 27.8 R19= 30.00 D19= 3.0 N10=1.49171 ν10= 57.4 R20= -35.32 D20= 16.0 R21= アイホ゜イント Ｒ１９面非球面 Ａ＝ ０ Ｂ＝−５×１０-5 Ｃ＝ ０ Ｄ＝ ０ Ｅ＝ ０ ＲＥ６／ｆ＝０．３１ ＲＥ７／ｆ＝０．３７ −βＴ＝ ３．３ νP ＝ ６８．２ νN ＝２３．９ 数値実施例 ２ ファインダー倍率 0.35 〜1.14 2ω= 52.7°〜16.0° R 1= -19.00 D 1= 5.0 N 1=1.49171 ν 1= 57.4 R 2= -6.74 D 2= 12.8 R 3= 11.89 D 3= 3.0 N 2=1.49171 ν 2= 57.4 R 4= 103.40 D 4= 可変 R 5= 25.96 D 5= 2.8 N 3=1.48749 ν 3= 70.2 R 6= -32.57 D 6= 0.5 R 7= 10.42 D 7= 2.8 N 4=1.48749 ν 4= 70.2 R 8= 55.51 D 8= 1.22 R 9= 10.50 D 9= 1.5 N 5=1.84666 ν 5= 23.9 R10= 5.50 D10= 1.5 R11= 6.79 D11= 2.5 N 6=1.51633 ν 6= 64.1 R12= 10.50 D12= 可変 R13= 20.43 D13= 5.0 N 7=1.49171 ν 7= 57.4 R14= ∞ D14= 0.2 R15= ∞ D15= 5.0 N 8=1.49171 ν 8= 57.4 R16= -50.00 D16= 2.78 R17= 30.00 D17= 3.0 N 9=1.49171 ν 9= 57.4 R18= -35.32 D18= 16.0 R19= アイホ゜イント Ｒ２面非球面 Ａ＝ ０ Ｂ＝ ４．０８×１０-4 Ｃ＝ １．９３×１０-5 Ｄ＝−８．０６×１０-7 Ｅ＝ １．６２×１０-8 Ｒ１７面非球面 Ａ＝ ０ Ｂ＝−５×１０-5 Ｃ＝ ０ Ｄ＝ ０ Ｅ＝ ０ ＲＥ６／ｆ＝０．３ ＲＥ７／ｆ＝０．３８ −βＴ＝ ３．３ νP ＝ ６８．２ νN ＝２３．９The aspherical shape has an X axis in the optical axis direction, an H axis in a direction perpendicular to the optical axis, a positive traveling direction of the light, R is a paraxial radius of curvature,
When A, B, C, D, and E are each aspheric coefficients It is represented by the following equation. Numerical Example 1 Finder magnification 0.35 to 1.14 2ω = 52.7 ° to 16.0 ° R 1 = -35.00 D 1 = 3.0 N 1 = 1.49171 ν 1 = 57.4 R 2 = -9.51 D 2 = 0.5 R 3 = 22.00 D 3 = 3.5 N 2 = 1.60311 ν 2 = 60.7 R 4 = -17.85 D 4 = 12.8 R 5 = 11.89 D 5 = 3.0 N 3 = 1.49171 ν 3 = 57.4 R 6 = 103.40 D 6 = Variable R 7 = 26.28 D 7 = 2.8 N 4 = 1.48749 ν 4 = 70.2 R 8 = -31.83 D 8 = 0.5 R 9 = 11.51 D 9 = 2.8 N 5 = 1.48749 ν 5 = 70.2 R10 = 55.88 D10 = 1.3 R11 = 10.20 D11 = 1.5 N 6 = 1.84666 ν 6 = 23.9 R12 = 5.60 D12 = 1.5 R13 = 6.62 D13 = 2.5 N 7 = 1.51633 ν 7 = 64.1 R14 = 10.50 D14 = Variable R15 = 20.43 D15 = 5.0 N 8 = 1.49171 ν 8 = 57.4 R16 = ∞ D16 = 0.2 R17 = ∞ D17 = 5.0 N 9 = 1.49171 ν 9 = 57.4 R18 = -50.00 D18 = 27.8 R19 = 30.00 D19 = 3.0 N10 = 1.49171 ν10 = 57.4 R20 = -35.32 D20 = 16.0 R21 = Eye point R19 aspheric surface A = 0 B = -5 × 10 -5 C = 0 D = 0 E = 0 RE6 / f = 0.31 RE7 / f = 0.37 −βT = 3.3 ν P = 68.2 ν N = 23.9 Numerical example 2 Finder magnification 0.35 to 1.14 2ω = 52.7 ° to 16.0 ° R 1 = -19.00 D 1 = 5.0 N 1 = 1.49171 ν 1 = 57.4 R 2 = -6.74 D 2 = 12.8 R 3 = 11.89 D 3 = 3.0 N 2 = 1.49171 ν 2 = 57.4 R 4 = 103.40 D 4 = Variable R 5 = 25.96 D 5 = 2.8 N 3 = 1.48749 ν 3 = 70.2 R 6 = -32.57 D 6 = 0.5 R 7 = 10.42 D 7 = 2.8 N 4 = 1.48749 ν 4 = 70.2 R 8 = 55.51 D 8 = 1.22 R 9 = 10.50 D 9 = 1.5 N 5 = 1.84666 ν 5 = 23.9 R10 = 5.50 D10 = 1.5 R11 = 6.79 D11 = 2.5 N 6 = 1.51633 ν 6 = 64.1 R12 = 10.50 D12 = Variable R13 = 20.43 D13 = 5.0 N 7 = 1.49171 ν 7 = 57.4 R14 = ∞ D14 = 0.2 R15 = ∞ D15 = 5.0 N 8 = 1.49171 ν 8 = 57.4 R16 =- 50.00 D16 = 2.78 R17 = 30.00 D17 = 3.0 N 9 = 1.49171 ν 9 = 57.4 R18 = -35.32 D18 = 16.0 R19 = Eye point R2 surface aspheric surface A = 0 B = 4.08 × 10 -4 C = 1.93 × 10 -5 D = −8.06 × 10 -7 E = 1.62 × 10 -8 R17 surface aspheric surface A = 0 B = -5 × 10 -5 C = 0 D = 0 E = 0 RE6 / f = 0.3 RE7 / f = 0.38 -βT = 3.3 ν P = 68.2 ν N = 23.9
【００３１】[0031]
【発明の効果】本発明によればエレクター系のレンズ構
成を前述の如く適切に設定することにより、変倍比３．
３と高変倍比、高倍率でありながら比較的レンズ全長が
短く、しかも簡易な構成で諸収差を良好に補正した高い
光学性能を有する実像式変倍ファインダー光学系を達成
することができる。According to the present invention, the zoom ratio is set to 3.
Thus, a real image type variable magnification finder optical system having a high magnification ratio, a high magnification ratio, a relatively short overall lens length, and a high optical performance with a simple configuration and excellent correction of various aberrations can be achieved.
【図１】 本発明の数値実施例１のレンズ断面図。FIG. 1 is a lens cross-sectional view of Numerical Example 1 of the present invention.
【図２】 本発明の数値実施例２のレンズ断面図。FIG. 2 is a lens cross-sectional view of Numerical Example 2 of the present invention.
【図３】 本発明の数値実施例１の広角端の諸収差図。FIG. 3 is a diagram illustrating various aberrations at a wide-angle end according to Numerical Embodiment 1 of the present invention.
【図４】 本発明の数値実施例１の中間の諸収差図。FIG. 4 is a diagram showing various aberrations in the intermediate state of Numerical Example 1 of the present invention.
【図５】 本発明の数値実施例１の望遠端の諸収差図。FIG. 5 is a diagram illustrating various aberrations at the telephoto end according to Numerical Example 1 of the present invention.
【図６】 本発明の数値実施例２の広角端の諸収差図。FIG. 6 is a diagram illustrating various aberrations at a wide angle end according to Numerical Example 2 of the present invention.
【図７】 本発明の数値実施例２の中間の諸収差図。FIG. 7 is a diagram showing various aberrations in the intermediate state of Numerical Example 2 of the present invention.
【図８】 本発明の数値実施例２の望遠端の諸収差図。FIG. 8 is a diagram showing various aberrations at the telephoto end according to Numerical Example 2 of the present invention.
１ 対物レンズ １ａ 前方レンズ群 １ｂ 第１フィールドレンズ １ｃ 第１次結像面 ２ エレクター系 ３ 第２フィールドレ
ンズ ３ａ 第２結像面 ４ 接眼レンズ ５ アイポイントDESCRIPTION OF SYMBOLS 1 Objective lens 1a Front lens group 1b First field lens 1c Primary imaging surface 2 Erector system 3 Second field lens 3a Second imaging surface 4 Eyepiece 5 Eye point
Claims (1)
インダー像をエレクター系により所定面上に第２ファイ
ンダー像として再結像させ、該第２ファインダー像を接
眼レンズを介して観察する際、該対物レンズと該エレク
ター系を光軸上各々異った量だけ移動させて変倍を行う
と共に、該エレクター系を物体側から順に両レンズ面が
凸面の正の第１レンズ、物体側に強い屈折面を有した正
の第２レンズ、物体側に凸面を向けたメニスカス状の負
の第３レンズ、そして物体側に凸面を向けたメニスカス
状の正の第４レンズの４つのレンズより構成し、第ｉ番
目のレンズ面の曲率半径をＲＥｉ、該エレクター系中の
正レンズと負レンズの材質のアッベ数の平均値を各々ν
P ，νN 、該エレクター系の望遠側での結像倍率をβ
Ｔ、該エレクター系の焦点距離をｆとしたとき ０．２＜ ＲＥ６／ｆ ＜０．４ ０．３＜ ＲＥ７／ｆ ＜０．５ ２．５＜ −βＴ ＜４．５ ２３ ＜ νN ＜２８ ６０ ＜ νP ＜７５ なる条件を満足することを特徴とする実像式変倍ファイ
ンダー光学系。When a first finder image formed by an objective lens is re-imaged as a second finder image on a predetermined surface by an erector system, and the second finder image is observed through an eyepiece, The objective lens and the erector system are moved by different amounts on the optical axis to perform zooming, and the erector system is sequentially positive from the object side with a positive first lens having both convex lens surfaces and a strong refraction toward the object side. A positive second lens having a surface, a negative third meniscus lens having a convex surface facing the object side, and a fourth positive meniscus lens having a convex surface facing the object side, The radius of curvature of the i-th lens surface is REi, and the average value of the Abbe numbers of the materials of the positive lens and the negative lens in the erector system is ν, respectively.
P , ν N , and the imaging magnification on the telephoto side of the erector system is β
T, when the focal length of the erector system is f, 0.2 <RE6 / f <0.4 0.3 <RE7 / f <0.5 2.5 <-βT <4.523 <ν N < 28 60 <ν P <real image type zoom finder optical system, characterized by satisfying the 75 following condition.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3033664A JP2806056B2 (en) | 1991-02-01 | 1991-02-01 | Real image type variable magnification finder optical system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3033664A JP2806056B2 (en) | 1991-02-01 | 1991-02-01 | Real image type variable magnification finder optical system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04247417A JPH04247417A (en) | 1992-09-03 |
| JP2806056B2 true JP2806056B2 (en) | 1998-09-30 |
Family
ID=12392727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3033664A Expired - Fee Related JP2806056B2 (en) | 1991-02-01 | 1991-02-01 | Real image type variable magnification finder optical system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2806056B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09197269A (en) * | 1996-01-18 | 1997-07-31 | Minolta Co Ltd | Finder optical system |
| JPWO2006038266A1 (en) * | 2004-09-30 | 2008-05-15 | 邦夫 島田 | Microscope zoom objective lens |
| US11774732B2 (en) | 2017-01-13 | 2023-10-03 | Torrey Pines Logic, Inc. | Continuous zoom afocal lens assembly |
-
1991
- 1991-02-01 JP JP3033664A patent/JP2806056B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04247417A (en) | 1992-09-03 |
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