JPH0271218A - Focus detecting optical system - Google Patents
Focus detecting optical systemInfo
- Publication number
- JPH0271218A JPH0271218A JP1140045A JP14004589A JPH0271218A JP H0271218 A JPH0271218 A JP H0271218A JP 1140045 A JP1140045 A JP 1140045A JP 14004589 A JP14004589 A JP 14004589A JP H0271218 A JPH0271218 A JP H0271218A
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- Prior art keywords
- lens
- imaging
- condenser lens
- image
- optical system
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- 230000003287 optical effect Effects 0.000 title claims description 34
- 238000003384 imaging method Methods 0.000 claims description 70
- 238000001514 detection method Methods 0.000 claims description 26
- 238000003491 array Methods 0.000 claims description 9
- 210000001747 pupil Anatomy 0.000 claims description 5
- 230000004075 alteration Effects 0.000 abstract description 30
- 238000002407 reforming Methods 0.000 abstract 6
- 206010073261 Ovarian theca cell tumour Diseases 0.000 abstract 1
- 208000001644 thecoma Diseases 0.000 abstract 1
- 238000004519 manufacturing process Methods 0.000 description 10
- 206010010071 Coma Diseases 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 101100289061 Drosophila melanogaster lili gene Proteins 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000011514 reflex Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
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Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、−眼レフレックスカメラ等に用いられる焦点
検出用光学系に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a focus detection optical system used in a -eye reflex camera or the like.
結像レンズにより結像される一次像を、コンデンサーレ
ンズと一対の再結像レンズとから成る再結像光学系によ
って一対のセンサアレイ上に夫々再結像させ、これら二
像の光強度分布を比較し相関演算することによって、二
像の間隔を求めてピントズレ量を得るような焦点検出用
光学系がある。即ち、上記演算により求められた二像間
隔をYo、ある点での二像間隔をYIとすると、それら
の差δ=Y + Y oとデフォーカス量とは対応関
係があり、この差を求めることで焦点検出を行なうこと
ができるのである。The primary images formed by the imaging lens are respectively re-imaged onto a pair of sensor arrays by a re-imaging optical system consisting of a condenser lens and a pair of re-imaging lenses, and the light intensity distribution of these two images is There is an optical system for focus detection that calculates the distance between two images and obtains the amount of focus shift by comparing and calculating the correlation. That is, if the distance between the two images obtained by the above calculation is Yo, and the distance between the two images at a certain point is YI, there is a correspondence between the difference δ=Y + Yo and the amount of defocus, and this difference is found. This allows focus detection to be performed.
このような焦点検出用光学系は従来から数多く提案され
ているが、近年、焦点検出精度を向上させるために諸収
差を良好に補正した光学系が提案されるようになってき
ている。Many such optical systems for focus detection have been proposed in the past, but in recent years, optical systems in which various aberrations are well corrected have been proposed in order to improve focus detection accuracy.
例えば、特開昭60−32012号公報および特開昭6
2−25715号公報に開示された焦点検出用光学系は
、いずれも歪曲収差補正のためにコンデンサーレンズの
少なくとも一面を回転双曲面又は回転楕円面等の非球面
にしている。また、特開昭62−69217号公報に開
示された焦点検出用光学系は、再結像レンズの入射側面
と射出側面とを偏心させることにより、更に、特開昭6
2−79407号公報に開示された焦点検出用光学系は
、再結像レンズの一方の面を球面にし他方の面をプリズ
ム作用を持った傾斜面とすることにより、夫々歪曲収差
および色収差の補正を行なっている。For example, JP-A-60-32012 and JP-A-6
In all of the focus detection optical systems disclosed in Japanese Patent No. 2-25715, at least one surface of the condenser lens is an aspheric surface such as a hyperboloid of revolution or an ellipsoid of revolution in order to correct distortion aberration. Furthermore, the focus detection optical system disclosed in Japanese Patent Application Laid-Open No. 62-69217 is further improved by decentering the entrance side surface and the exit side surface of the re-imaging lens.
The focus detection optical system disclosed in Publication No. 2-79407 corrects distortion aberration and chromatic aberration by making one surface of the reimaging lens a spherical surface and the other surface an inclined surface having a prism effect. is being carried out.
ところが、レンズの非球面は精度管理がむずかしく、球
面に比較して出来映えの簡便な評価法が確立されていな
いため、所望の性能の焦点検出用光学系を製作すること
が困難である、という問題があった。また、レンズの人
出射面が共軸でなかったり特殊な形状である場合も製作
精度の管理が困難であるため、これもまた所望の性能の
焦点検出用光学系を製作することが困難である、という
問題があった。However, the accuracy of the aspherical surface of the lens is difficult to control, and there is no established method for easily evaluating the workmanship compared to that of a spherical surface, making it difficult to manufacture a focus detection optical system with the desired performance. was there. Additionally, if the exit surface of the lens is not coaxial or has a special shape, it is difficult to control manufacturing accuracy, which also makes it difficult to manufacture a focus detection optical system with the desired performance. There was a problem.
本発明は、上記問題点に鑑み、諸収差を良好に補正する
ことができ、且つ所望の性能のものを製作することが容
易である焦点検出用光学系を提供することを目的として
いる。In view of the above problems, it is an object of the present invention to provide a focus detection optical system that can satisfactorily correct various aberrations and that is easy to manufacture with desired performance.
〔課題を解決するための手段および作用〕本発明による
焦点検出用光学系は、結像レンズの予定結像面付近に位
置していて、該結像レンズの射出瞳を伝送するコンデン
サーレンズと、前記結像レンズにより結像せしめられた
一次像を一対のセンサアレイ上に夫々再結像させる一対
の再結像レンズとから成る焦点検出用光学系において、
前記コンデンサーレンズおよび再結像レンズが以下の条
件を満足することを特徴とするものである。[Means and effects for solving the problem] The focus detection optical system according to the present invention includes a condenser lens located near the expected image forming plane of the imaging lens and transmitting the exit pupil of the imaging lens; A focus detection optical system comprising a pair of re-imaging lenses that respectively re-image the primary images formed by the imaging lens on a pair of sensor arrays,
The condenser lens and the reimaging lens are characterized in that they satisfy the following conditions.
(1) 1.5< l R+/ Rt(2) 0.
1< B S<0.25(3)0.7<ts/f3
(4) 0.1< l R3/R41<4但し、R+
、 Rzは夫々前記コンデンサーレンズの入射側面お
よび射出側面の曲率半径、B。(1) 1.5<l R+/Rt(2) 0.
1< B S<0.25 (3) 0.7<ts/f3 (4) 0.1< l R3/R41<4 However, R+
, Rz are the radii of curvature of the entrance side and exit side of the condenser lens, respectively, and B.
は前記再結像レンズの結像倍率、fsは再結像レンズの
焦点距離、tsは再結像レンズの軸上厚、R3、R4は
夫々再結像レンズの入射側面および射出側面の曲率半径
である。is the imaging magnification of the re-imaging lens, fs is the focal length of the re-imaging lens, ts is the axial thickness of the re-imaging lens, and R3 and R4 are the radii of curvature of the entrance and exit sides of the re-imaging lens, respectively. It is.
焦点検出用光学系において、検出精度にかかわる条件と
しては二像間隔が正しく求まることが重要であり、その
ため光学系の結像性能が問題となってくる。その結像性
能で重要なのは、結像レンズの予定結像面上の焦点検出
に用いられる領域(測距域)内のどこに一次像があって
も、その二次像すなわちセンサアレイ上に形成される二
像が同じ結像特性で形成されていることである。In a focus detection optical system, it is important to determine the distance between two images correctly as a condition related to detection accuracy, and therefore the imaging performance of the optical system becomes an issue. What is important about its imaging performance is that no matter where the primary image is located within the area used for focus detection (rangefinding area) on the planned imaging plane of the imaging lens, the secondary image, that is, the image formed on the sensor array. The two images are formed with the same imaging characteristics.
第1図は本発明の焦点検出用光学系の基本構成を示す図
である。Loはカメラの撮影レンズなどのような結像レ
ンズ、Aはその予定結像面で、カメラで言えばフィルム
面と光学的に等価な位置がこれに相当する。予定結像面
Aの近くにコンデンサーレンズL+が設けられ、またこ
のコンデンサーレンズLLにより伝送された結像レンズ
L0の射出瞳Pの像位置に一対の開口を有する絞りSが
置かれている。絞りSの背後には一対の再結像レンズL
z、Liおよび一対のセンサアレイSA、、SAtが、
間隔りを隔てて結像レンズの光軸0に対称に配置されて
いる。FIG. 1 is a diagram showing the basic configuration of a focus detection optical system of the present invention. Lo is an imaging lens such as a photographing lens of a camera, and A is its intended imaging plane, which corresponds to a position optically equivalent to the film plane in a camera. A condenser lens L+ is provided near the planned imaging plane A, and a diaphragm S having a pair of apertures is placed at the position of the image of the exit pupil P of the imaging lens L0 transmitted by the condenser lens LL. Behind the aperture S is a pair of re-imaging lenses L.
z, Li and a pair of sensor arrays SA, , SAt,
They are arranged symmetrically with respect to the optical axis 0 of the imaging lens at intervals.
この光学系において、結像レンズL0によりその予定結
像面A上に形成された一層像■。は、コンデンサーレン
ズL+ と再結像レンズL、。In this optical system, a single layer image (2) is formed on the intended imaging plane A by the imaging lens L0. are a condenser lens L+ and a reimaging lens L.
L、によりセンサアレイSA、、S Az上に再結像さ
れるが、各再結像レンズに対する光線の角度が違うため
に、センサアレイSA1.SA、上の二つの二次像II
、12 は非対称の結像となる傾向にある。そこで、本
発明に係る焦点検出用光学系においては、その非対称の
結像の原因となる歪曲収差およびコマ収差が問題となっ
てくる。are reimaged onto the sensor arrays SA, , S Az by the sensor arrays SA1 . SA, upper two secondary images II
, 12 tends to result in asymmetric imaging. Therefore, in the focus detection optical system according to the present invention, distortion aberration and coma aberration that cause the asymmetric image formation become a problem.
ここで、これらの収差発生のメカニズムについて説明す
ると以下の通りである。Here, the mechanism of occurrence of these aberrations will be explained as follows.
まず、予定結像面A上の一次像I0は、コンデンサーレ
ンズL1によって虚像として拡大投影されるわけである
が、その時発生する歪曲収差はコンデンサーレンズL、
の拡大倍率によりほぼ決まる。また、コンデンサーレン
ズL1 は二つの再結像レンズLx、L、と組合わされ
て二つの二次像1.12を形成するが、各再結像レンズ
に対しコンデンサーレンズが逆方向に偏心しているため
、コンデンサーレンズにおいて非対称の歪曲収差が発生
する。この歪曲収差の非対称性のバランスはコンデンサ
ーレンズL、の各面の曲率半径の比率により大きく変化
する。First, the primary image I0 on the planned imaging plane A is enlarged and projected as a virtual image by the condenser lens L1, but the distortion that occurs at that time is caused by the condenser lens L,
It is almost determined by the magnification factor. In addition, the condenser lens L1 is combined with the two re-imaging lenses Lx and L to form two secondary images 1.12, but since the condenser lens is decentered in the opposite direction to each re-imaging lens, , asymmetric distortion occurs in a condenser lens. The balance of the asymmetry of this distortion greatly changes depending on the ratio of the curvature radii of each surface of the condenser lens L.
次に、その虚像をセンサアレイS A、、 S A。Next, the virtual image is sent to the sensor array SA, , SA.
上に結像させる働きをするのが再結像レンズLx、Ls
であるが、そこで発生する歪曲収差はコンデンサーレン
ズL、で発生する歪曲収差に比較して絶対量は小さいが
、レンズの厚みやその曲率半径の比率などにより発生量
は変化する。The re-imaging lenses Lx and Ls function to form an image upward.
However, although the absolute amount of distortion generated there is smaller than the distortion generated in the condenser lens L, the amount generated changes depending on the thickness of the lens, the ratio of its radius of curvature, etc.
第2図はコンデンサーレンズL、での像■、。Figure 2 shows the image taken by the condenser lens L.
■、に対する歪曲収差の発生状況を示すグラフ、第3図
は同じく再結像レンズI7□+ L 3での像1+、1
gに対する歪曲収差の発生状況を示すグラフ(横軸は曲
率半径の比率(入射面R+ /射出面R0)、縦軸は歪
曲収差を示す。)である。Graph showing the occurrence of distortion aberration for , Figure 3 is the same image 1+, 1 with the re-imaging lens I7□+L 3.
This is a graph showing the occurrence of distortion aberration with respect to g (the horizontal axis shows the ratio of the radius of curvature (incidence surface R+/exit surface R0), and the vertical axis shows the distortion aberration).
第3図では再結像レンズL 、、 L 、の肉厚りを3
.5mm又は1.5mに設定した場合を示している。In Figure 3, the thickness of the re-imaging lenses L, L, is 3.
.. The case where the distance is set to 5 mm or 1.5 m is shown.
このように、コンデンサーレンズL、ではプラスの歪曲
収差が、再結像レンズLl+L3ではマイナスの歪曲収
差が夫々発生しているのが判る。又、再結像レンズLt
、L、の肉厚tを厚くすることによってそのマイナスの
歪曲収差が増すことが判る。In this way, it can be seen that positive distortion aberration occurs in the condenser lens L, and negative distortion aberration occurs in the reimaging lens L1+L3. In addition, the re-imaging lens Lt
It can be seen that by increasing the wall thickness t of ,L, the negative distortion increases.
以上の解析に基いて、本発明においてはコンデンサーレ
ンズ、再結像レンズの夫々で発生する収差量を一定レベ
ル以下に抑えるとともに、コンデンサーレンズと再結像
レンズの収差を互いに相殺させることにより、総合的に
歪曲収差およびコマ収差を良好に補正するようにした。Based on the above analysis, in the present invention, the amount of aberration generated in each of the condenser lens and the re-imaging lens is suppressed to below a certain level, and the aberrations of the condenser lens and the re-imaging lens are canceled out to each other. Distortion aberration and coma aberration are effectively corrected.
まずコンデンサーレンズに関しては条件(1)を満足す
ることが必要である。コンデンサーレンズによる歪曲収
差はコンデンサーレンズL1の前後面の曲率半径の比率
(R1/Rz)が1.5よりも小さい場合は、プラスに
大きく発生し、且つ像I、に対応する歪曲収差が非常に
大きくなって非対称性が増大してしまう。非対称性が増
大することは最終的にはコマ収差の悪化につながる。こ
の場合、簡単な再結像レンズLILIでは収差を補正し
きれなくなり、コンデンサーレンズL、に非球面を採用
することによりコンデンサーレンズL、の歪曲収差を補
正することが必要となってくる。First, it is necessary for the condenser lens to satisfy condition (1). Distortion caused by the condenser lens occurs positively when the ratio (R1/Rz) of the radius of curvature of the front and rear surfaces of the condenser lens L1 is smaller than 1.5, and the distortion corresponding to the image I is extremely large. This increases the asymmetry. Increasing asymmetry ultimately leads to worsening of coma. In this case, the simple re-imaging lens LILI cannot fully correct the aberrations, and it becomes necessary to correct the distortion of the condenser lens L by adopting an aspherical surface for the condenser lens L.
そこで本発明においては、コンデンサーレンズL、の前
面及び後面の曲率半径の比率(R1/Ri)を1.5よ
りも大きく設定し、コンデンサーレンズL、で発生する
歪曲収差、コマ収差を再結像レンズL□、L3で良好に
補正し得るようにしている。Therefore, in the present invention, the ratio (R1/Ri) of the radius of curvature of the front surface and the rear surface of the condenser lens L is set larger than 1.5, and the distortion and coma aberration occurring in the condenser lens L are re-imaged. This can be well corrected with lenses L□ and L3.
次に、再結像レンズに関しては条件(2)、 (3)お
よび(4)を満足することが必要である。Next, it is necessary for the re-imaging lens to satisfy conditions (2), (3) and (4).
条件(2)は再結像レンズの倍率を定めたもので、上限
を越えるとコンデンサーレンズと組合わせた光学系全体
の倍率を小さくすることが不可能となり、測距域を大き
くとれなくなる。倍率を小さくするためにコンデンサー
レンズの屈折力を弱めると、コンデンサーレンズの瞳を
伝送する機能が損なわれる。下限を越えると再結像レン
ズによる歪曲収差発生量が大きくなり、再結像レンズを
球面のみの構成とすることが不可能になる。Condition (2) determines the magnification of the re-imaging lens; if the upper limit is exceeded, it becomes impossible to reduce the magnification of the entire optical system combined with the condenser lens, making it impossible to obtain a large range of distance measurement. If the refractive power of the condenser lens is weakened in order to reduce the magnification, the ability of the condenser lens to transmit the pupil will be impaired. If the lower limit is exceeded, the amount of distortion generated by the re-imaging lens becomes large, and it becomes impossible to configure the re-imaging lens with only a spherical surface.
条件(3)は再結像レンズの肉厚を定めたもので、下限
を越えると、コンデンサーレンズにより発生する歪曲収
差を再結像レンズで補うことができなくなってしまい、
コンデンサーレンズに非球面を使用する等によりコンデ
ンサーレンズ自身で歪曲収差の発生を抑える必要が生ず
る。尚、ts/fsが2を越えると、再結像レンズが厚
くなりすぎて射出成型を行なう場合に時間がかかりすぎ
る等、製造上の問題が生ずる虞れがある。Condition (3) determines the thickness of the re-imaging lens; if the lower limit is exceeded, the re-imaging lens will no longer be able to compensate for the distortion caused by the condenser lens.
By using an aspheric surface in the condenser lens, it becomes necessary to suppress the occurrence of distortion in the condenser lens itself. If ts/fs exceeds 2, there is a risk that the re-imaging lens will become too thick, leading to manufacturing problems such as too much time required for injection molding.
条件(4)は再結像レンズの形状を定めたもので、上限
を越えると、二次像I、、1.に対する歪曲収差をバラ
ンス良く補正することができなくなる。つまり、■2に
対するマイナスの歪曲収差発生量を確保しようとすると
、11に対するマイナスの歪曲収差の発生量が大きくな
りすぎてしまう。下限を越えると、コンデンサーレンズ
で発生したプラスの歪曲収差が再結像レンズにより打ち
消されずに残ってしまい、全系の結像性能が劣化する。Condition (4) defines the shape of the re-imaging lens, and if the upper limit is exceeded, the secondary images I, , 1 . It becomes impossible to correct distortion aberration in a well-balanced manner. In other words, if an attempt is made to ensure the amount of negative distortion generated for 2, the amount of negative distortion generated for 11 will become too large. When the lower limit is exceeded, the positive distortion generated by the condenser lens is not canceled out by the re-imaging lens and remains, degrading the imaging performance of the entire system.
尚、条件(4)を満足させることは、特に再結像レンズ
が両凸レンズである場合に効果的である。Note that satisfying condition (4) is particularly effective when the re-imaging lens is a biconvex lens.
以上のような構成により、測距域のどこに一次像があっ
ても、センサアレイSA、、SAZ上の二次像の結像性
能が同じに保たれ、焦点検出精度が太き(向上する。ま
た、コンデンサーレンズL+ に非球面を用いたり、再
結像レンズLz、Lsの前後面を非共軸または特殊な形
状にしたりする必要がないので、製作精度管理が容易で
あり、所望の性能のものを製作することが容易である。With the above configuration, no matter where the primary image is located in the distance measurement area, the imaging performance of the secondary images on the sensor arrays SA, . In addition, since there is no need to use an aspheric surface for the condenser lens L+ or to make the front and rear surfaces of the re-imaging lenses Lz and Ls non-coaxial or special shapes, it is easy to control manufacturing accuracy and achieve the desired performance. It is easy to manufacture things.
次に本発明による焦点検出用光学系の実施例を示す。r
i (i−1,2,・・−・)はレンズ面の曲率半径
、di (i=1.2. ・−)はレンズ肉厚或は空
気間隔、doはコンデンサーレンズから予定結像面Aま
での距離、nl(i=1゜2、−・)はレンズの屈折率
、ri (i=1゜2 、 −)はアツベ数、βは光学
系全体の倍率、R,/R2はコンデンサーレンズL、の
前面及び後面の曲率を夫々R+ 、 Rz とした時
の比率、Dは二つの再結像レンズL2.L3の光軸間の
距離である。Next, an embodiment of a focus detection optical system according to the present invention will be described. r
i (i-1, 2,...-) is the radius of curvature of the lens surface, di (i=1.2.-) is the lens thickness or air gap, and do is the distance from the condenser lens to the planned imaging plane A. distance to The ratio, D, is the ratio when the curvatures of the front and rear surfaces of L, are respectively R+ and Rz, and D is the ratio of the two re-imaging lenses L2. This is the distance between the optical axes of L3.
r 、 =35.86
dl =3.Onl =1.49216 ν1
=57.5rg =−8,96
at =16.6
r、 =3.20
d3 =3.0 nz ””’1.49216
vt =57.5r’ =−3,20
β=−0,27R,/R,=4.0 D=1.4β
s=0.19 ts/fs=0.88 Rs/
R4=1本実施例において、予定結像面A上にあって
光軸から2.8mの高さの一次像のコンデンサーレンズ
L、による歪曲収差は、像■1に対応する主光線につい
ては+0.8%であり、像■2に対応する主光線につい
ては+1.5%であった。r, =35.86 dl =3. Onl =1.49216 ν1
=57.5rg =-8,96 at =16.6 r, =3.20 d3 =3.0 nz ""'1.49216
vt =57.5r' =-3,20 β=-0,27R,/R, =4.0 D=1.4β
s=0.19 ts/fs=0.88 Rs/
R4=1 In this example, the distortion caused by the condenser lens L of the primary image located on the planned imaging plane A and at a height of 2.8 m from the optical axis is +0 for the chief ray corresponding to image ■1. .8%, and the principal ray corresponding to image (2) was +1.5%.
それに対して、再結像レンズLl’L3による歪曲収差
は像11については一〇、75%であり、像■2につい
ては−1,4%である。この両レンズの組合せにより、
総合的に非常に良好に諸収差を補正することができてい
る。On the other hand, the distortion caused by the re-imaging lens Ll'L3 is 10.75% for the image 11, and -1.4% for the image 2. By combining these two lenses,
Overall, various aberrations can be corrected very well.
その結果、本実施例においては、予定結像面A上にあっ
て光軸から2.8mmの高さの一次像についてのセンサ
アレイSA、、SA2上における像高誤差(I!、+
l−z )は1.7μm(歪曲収差0.11%)で
あった。As a result, in this example, the image height error (I!, +
l-z) was 1.7 μm (distortion aberration 0.11%).
このようにコンデンサーレンズL、 と再結像レンズ
L、、L、の夫々の収差の発生量が相殺されるように両
レンズの組合せを選ぶことにより、コンデンサーレンズ
L、に非球面を用いずに球面のみで、而も再結像レンズ
L、、L、の前後面を非共軸又は特殊な形状にせずに、
良好に収差を補正することができた。In this way, by selecting a combination of the condenser lens L, and the reimaging lens L, L, so that the amount of aberration generated by each lens is canceled out, it is possible to avoid using an aspheric surface in the condenser lens L, Only spherical surfaces, and without making the front and rear surfaces of the re-imaging lenses L, L, non-coaxial or special shapes,
Aberrations were successfully corrected.
一第」し実」1劃−
do”’3.7
r 、 =28.37
d、 −3,On、 =1.49216 v、 =
57.5r2 =−9,46
ci、 =16.4
rs=2.34
da =3.On= =1.49216 vt =
57.5r’ =−4,92
β−−0,26R1/RZ =3.0 D=1
.4βs−0,17ts/fs=0.80 R3/
R4=0.48本実施例においては、予定結像面A上に
あって光軸から2.8肛の高さの一次像についてのセン
サアレイSA、、SA2上における像高誤差は2μm(
歪曲収差0.14%)であった。1st "Shijime" 1st part - do"'3.7 r, =28.37 d, -3,On, =1.49216 v, =
57.5r2 =-9,46 ci, =16.4 rs=2.34 da =3. On= =1.49216 vt=
57.5r' =-4,92 β--0,26R1/RZ =3.0 D=1
.. 4βs-0,17ts/fs=0.80 R3/
R4=0.48 In this example, the image height error on the sensor arrays SA, SA2 for the primary image located on the planned imaging plane A and at a height of 2.8 mm from the optical axis is 2 μm (
The distortion aberration was 0.14%).
見↓z31
dO=2.8
r 、=CD
d + =3.On 1=1.49216 v +
=57.5r、 =−7,28
d2=16.88
r3=5.00
di =3.5 n2 =1.49216 ν2
=57.5r’ =−2,50
β=−0,27R,/R2−ω D=1.32βs−
0,18ts/fs=0.87 R3/R4=2本実
施例においては、予定結像面A上にあって光軸から2.
8価の高さの一次像についてのセンサアレイSA、、S
AZ上における像高誤差は0.5μm(歪曲収差−0,
03%)であった。又、本実施例は、コンデンサーレン
ズL1の予定結像面A側の面を平面にしているので、製
作が一層容易である。See↓z31 dO=2.8 r, =CD d + =3. On 1=1.49216 v +
=57.5r, =-7,28 d2=16.88 r3=5.00 di =3.5 n2 =1.49216 ν2
=57.5r' =-2,50 β=-0,27R,/R2-ω D=1.32βs-
0.18ts/fs=0.87 R3/R4=2 In this example, it is on the planned imaging plane A and is 2.5mm from the optical axis.
Sensor array SA,,S for the octavalent height primary image
The image height error on AZ is 0.5 μm (distortion -0,
03%). Further, in this embodiment, since the surface of the condenser lens L1 on the side of the intended image forming plane A is made flat, manufacturing is easier.
l土裏皇■
do =3.4
r、 =19.38
d 1=3.On + =1.49216 v +
=57.5rt −−11,07
d、 =16.1
r、 −1,87
d3=3.5 n2 =1.49216 vt =
57.5r4−o。l Do Urako■ do =3.4 r, =19.38 d 1=3. On + =1.49216 v +
=57.5rt −-11,07 d, =16.1 r, −1,87 d3=3.5 n2 =1.49216 vt =
57.5r4-o.
β=−0,28R+/ Rz =1.75 D =1
.4β、−0,19ts/fs=o、92 R3/
R4=04=0例は、再結像レンズLz、Lsが物体側
に凸面をセンサ側に平面を夫々向けた平凸レンズで構成
されているため製作が一層容易である上に、予定結像面
A上にあって光軸から2.8鵬の高さの一次像について
のセンサアレイSA、。β=-0,28R+/Rz=1.75 D=1
.. 4β, -0,19ts/fs=o, 92 R3/
In the R4=04=0 example, the re-imaging lenses Lz and Ls are composed of plano-convex lenses with a convex surface facing the object side and a flat surface facing the sensor side, which makes manufacturing easier. Sensor array SA, for the primary image located on A and at a height of 2.8 degrees from the optical axis.
SA、上における像高誤差は2.8μm(歪曲収差0.
18%)であるなど、諸収差が非常に良好に補正されて
いる。The image height error at the top of SA is 2.8 μm (distortion is 0.
18%), and various aberrations are very well corrected.
上述の如く、本発明による焦点検出用光学系は、諸収差
を良好に補正することができ且つ所望の性能のものを製
作することが容易であるという実用上重要な利点を有し
ている。As described above, the focus detection optical system according to the present invention has important practical advantages in that it can satisfactorily correct various aberrations and is easy to manufacture with desired performance.
第1図は本発明による焦点検出用光学系の基本構成を示
す図、第2図及び第3図は夫々上記焦点検出用光学系の
コンデンサーレンズ及び再結像レンズでの歪曲収差の発
生状況を示すグラフである。
A・−・−・・・−・−−−−−−−−−−−−一
予定結像面Io ・−・−−−−−−−−・−一次像
1 +、 I 2 ’−−−−−−−−・−・−・−
・−・二次像L 、 −−−−−−−−−−−−−−
−−・コンデンサーレンズL t、 L a −−−
−−−−−−−−−−−−−一再結像レンズs −−
−−−−−−−−−−−・・・−−−−一−−−−−
絞りSA1.SAz
センサアレイ
第
図FIG. 1 shows the basic configuration of the focus detection optical system according to the present invention, and FIGS. 2 and 3 show the occurrence of distortion in the condenser lens and reimaging lens of the focus detection optical system, respectively. This is a graph showing. A.
Planned imaging plane Io ・−・−−−−−−−−・−Primary image 1 +, I 2 ′−−−−−−−−・−・−・−
・−・Secondary image L, −−−−−−−−−−−−−−
--・Condenser lens L t, L a ---
−−−−−−−−−−−−−1 reimaging lens s −−
−−−−−−−−−−−・−−−−1−−−−−
Aperture SA1. SAz sensor array diagram
Claims (1)
結像レンズの射出瞳を伝送するコンデンサーレンズと、
前記結像レンズにより結像せしめられた一次像を一対の
センサアレイ上に夫々再結像する一対の再結像レンズと
から成る焦点検出用光学系において、前記コンデンサー
レンズの入射側面および射出側面の曲率半径を夫々R_
1、R_2とするとき1.5<|R_1/R_2| を満足することを特徴とする焦点検出用光学系。 (2)結像レンズの予定結像面付近に位置していて、該
結像レンズの射出瞳を伝送するコンデンサーレンズと、
前記結像レンズにより結像せしめられた一次像を一対の
センサアレイ上に夫々再結像する一対の再結像レンズと
から成る焦点検出用光学系において、前記再結像レンズ
の倍率をB_s、焦点距離をf_s、軸上厚をt_s、
入射側面の曲率半径をR_3、射出側面の曲率半径をR
_4とするとき、 0.1<B_s<0.25 0.7<t_s/f_s 0.1<|R_3/R_4|<4 を満足することを特徴とする焦点検出用光学系。[Scope of Claims] (1) A condenser lens located near a planned imaging plane of an imaging lens and transmitting an exit pupil of the imaging lens;
In a focus detection optical system comprising a pair of re-imaging lenses that re-image the primary image formed by the imaging lens onto a pair of sensor arrays, an incident side surface and an exit side surface of the condenser lens The radius of curvature is R_
1. An optical system for focus detection, characterized in that, when R_2, 1.5<|R_1/R_2| is satisfied. (2) a condenser lens located near the expected imaging plane of the imaging lens and transmitting the exit pupil of the imaging lens;
In a focus detection optical system comprising a pair of re-imaging lenses that re-image the primary images formed by the imaging lenses onto a pair of sensor arrays, the magnification of the re-imaging lenses is B_s, Focal length is f_s, axial thickness is t_s,
The radius of curvature of the entrance side is R_3, and the radius of curvature of the exit side is R
An optical system for focus detection, characterized in that, when _4, 0.1<B_s<0.25 0.7<t_s/f_s 0.1<|R_3/R_4|<4.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63-141958 | 1988-06-09 | ||
JP14195888 | 1988-06-09 |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0271218A true JPH0271218A (en) | 1990-03-09 |
JP2716526B2 JP2716526B2 (en) | 1998-02-18 |
Family
ID=15304084
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1140045A Expired - Fee Related JP2716526B2 (en) | 1988-06-09 | 1989-06-01 | Optical system for focus detection |
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---|---|
JP (1) | JP2716526B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5267474A (en) * | 1992-10-23 | 1993-12-07 | Kohler Co. | Liquid-level sensor |
JP2011242586A (en) * | 2010-05-18 | 2011-12-01 | Canon Inc | Range finder and optical equipment having the same |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01224714A (en) * | 1988-03-04 | 1989-09-07 | Nikon Corp | Focus detecting optical system |
-
1989
- 1989-06-01 JP JP1140045A patent/JP2716526B2/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01224714A (en) * | 1988-03-04 | 1989-09-07 | Nikon Corp | Focus detecting optical system |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5267474A (en) * | 1992-10-23 | 1993-12-07 | Kohler Co. | Liquid-level sensor |
JP2011242586A (en) * | 2010-05-18 | 2011-12-01 | Canon Inc | Range finder and optical equipment having the same |
Also Published As
Publication number | Publication date |
---|---|
JP2716526B2 (en) | 1998-02-18 |
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