JPS6256913A - Focus detecting device - Google Patents

Abstract

PURPOSE:To improve the optical performance of the secondary object image of a photodetecting element array and to improve the accuracy of focus detection by splitting the two secondary object images vertically by using the 1st and the 2nd reflecting parts which have a reflecting surface in a specific shape for an image re-formation system CONSTITUTION:Two reflecting surfaces 6-122 and 6-222 of the 2nd reflection part which have different tilt angles are arranged divisionally in the image re-formation system 6 at right angles to the division direction of the two reflecting surfaces 6-121 and 6-222 of the 1st reflection part which have different tilt angles. Consequently, luminous flux passed through one of two image reforming lenses 6-11 and 6-21, e.g. 6-11 is reflected by the reflecting surface 6-121 of the 1st reflection part and then reflected only by the reflecting surface 6-122 of the 2nd reflection part to strike on the other reflecting surface 6-222, and the luminous flux is prevented from being mixed to improve the optical performance of the secondary object image on a photodetecting means 8. Consequently, high-accuracy focus detection is performed all the time.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は写真用カメラやビデオカメラ等に好適な焦点検
出装置に関し、特に撮影レンズの瞳を複数の領域ｌこ分
割し、各領域を通過する光束から複数の第２次物体像を
形成し、これら複数の第２次物体像の相対的位置関係を
検出することにより、撮影レンズの焦点状態を検出する
焦点検出装置に関するものである。Detailed Description of the Invention (Industrial Application Field) The present invention relates to a focus detection device suitable for photographic cameras, video cameras, etc., and in particular, a focus detection device that divides the pupil of a photographic lens into a plurality of regions and passes through each region. The present invention relates to a focus detection device that detects the focal state of a photographic lens by forming a plurality of secondary object images from a light beam and detecting the relative positional relationship of the plurality of secondary object images.

（従来の技術） 従来より比較的Ｑ”＋　：ｊ精度な受光型の焦点検出方
式に所謂像ずれ方式と呼ばれる方式があ゛る。(Prior Art) Conventionally, there is a method called the so-called image shift method as a light-receiving focus detection method with relatively high accuracy.

この像ずれ方式は例えば特開昭５２−９５２２１号公報
で提案されているように撮影レンズによる第１次物体像
の形成されるｔ定結像面の後方に１つ若しくは２つの１
１結像レンズを有する再結像系と、２つの受光素子列を
イｒする受光手段とを配置している。再結像系は撮影レ
ンズの２つの瞳領域を通過した光束を用いて第１次物体
像から２つの第２次物体像を各々の受光素子列面上に形
成している、２つの第２次物体像の受光素子列面」二の
相対的位置は撮影レンズの合焦状態により受光素ｒ−列
の素ｒの並び方向に横ずれ状態となって現われる。＆　
Ｊｂレンズの焦点検出はこのときの２つの第２次物体像
の相対的位置関係を受光手段により検出することにより
行っている。この為、像ずれ方式による焦点検出装置に
おいては第２次物体像の受光手段向上での光学性能が焦
点検出粒度に大きく　ｊＪ三晋してくる。This image shift method is proposed, for example, in Japanese Unexamined Patent Publication No. 52-95221.
A re-imaging system having one imaging lens and a light receiving means for illuminating two light receiving element rows are arranged. The re-imaging system forms two secondary object images from the primary object image on each of the light receiving element array surfaces using the light flux that has passed through the two pupil areas of the photographing lens. The relative position of the next object image on the light-receiving element row plane 2 appears as a lateral shift in the direction in which the light-receiving elements r-row elements r are lined up depending on the focusing state of the photographing lens. &
The focus of the Jb lens is detected by detecting the relative positional relationship between the two secondary object images using a light receiving means. For this reason, in a focus detection device based on the image shift method, the optical performance due to improvement of the light receiving means for the secondary object image is greatly affected by the focus detection grain size.

従来の像すれ方式による焦点検出装置においては、２つ
のプリズムな楔角が互いに逆になるように配置したプリ
ズム体を用い若しくは２つのＩ＋１結像レンズの一部に
屈折方向が互いに逆になるようなプリズムを付して撮影
レンズの瞳を２つに分割している。そして２つの第２次
物体像を瞳の分割方向と直交方向に分離し、２つの受光
素Ｙ−列を上下方向に平行に配置している。これにより
受光素子列の長さの拡大を図り、大きなディフォーカス
量があっても、２つの第２次物体像が互いに重複しない
ようにし、焦点検出範囲を拡大していた。In the conventional focus detection device using the image blur method, two prism bodies are arranged so that their wedge angles are opposite to each other, or a part of two I+1 imaging lenses is used so that the refraction directions are opposite to each other. A prism is attached to divide the pupil of the photographic lens into two. Two secondary object images are separated in a direction orthogonal to the pupil division direction, and two Y-rows of light receiving elements are arranged in parallel in the vertical direction. This increases the length of the light-receiving element array, prevents two secondary object images from overlapping each other even if there is a large amount of defocus, and expands the focus detection range.

しかしながら、従来はプリズムを用いて２つの第２次物
体像を分離していた為に、プリズムから、を曲収差や色
収差等の諸収差が発生し、第２次物体像の光学性能を著
しく低下させていた。However, since conventionally a prism was used to separate the two secondary object images, various aberrations such as curvature aberration and chromatic aberration were generated from the prism, significantly reducing the optical performance of the secondary object image. I was letting it happen.

この結果、２つの第２次物体像の相対的位置関係の検出
精度が低下し、焦点検出精度を低［させる大きな原因と
なっていた。As a result, the accuracy of detecting the relative positional relationship between the two secondary object images is reduced, which is a major cause of deterioration of the focus detection accuracy.

（発明が解決しようとする問題点） 本発明は像ずれ方式の焦点検出装置に右いて、第２次物
体像の光学性能を良好に維持しつつ高錆度な焦点検出を
可能とした焦点検出装置の提供を目的とする。(Problems to be Solved by the Invention) The present invention is directed to an image shift type focus detection device, which enables focus detection with high corrosion resistance while maintaining good optical performance of a secondary object image. The purpose is to provide equipment.

（問題点を解決するための−「段） Ｗ１影レンズの像面側に前記）最尤レンズの瞳を２つの
領域に分割し、分割した２つの瞳領域を通過する光束か
ら各々第２次物体像を形成する再結像系を配置し、前記
１１結像系の像面近傍に２つの受光よ−ｒ列より成る受
光手段を配置し、前記受光手段により前記２つの第２次
物体像の相対的位置関係を検出することにより前記撮影
レンズの焦点状態を検出する焦点検出装置において、１
）η記＋ｔｉ結像系はｉｌＧ結像レンズと該１ｒ１結像
レンズを通過した光束を１１７ｒ記２つの受光素子・列
に各々導光する為の傾角な異にした２つの反射面より成
る第１反射部と該第１Ｓ、射部の反射面の分割方向と直
交する方向に分割した傾角の異なる２つの反射面より成
る第２反射部とを有していることである。(Steps to solve the problem) The pupil of the maximum likelihood lens (above) is divided into two regions on the image plane side of the W1 shadow lens, and the second order is calculated from the light flux passing through the two divided pupil regions. A re-imaging system for forming an object image is arranged, and a light receiving means consisting of two light receiving rows is arranged near the image plane of the 11 imaging system, and the light receiving means forms the two secondary object images. In a focus detection device that detects a focus state of the photographing lens by detecting a relative positional relationship between
) η+ti imaging system consists of two reflecting surfaces with different inclinations for guiding the light beams passing through the ilG imaging lens and the 1r1 imaging lens to the two light receiving elements/rows in 117r. The second reflecting section is composed of two reflecting surfaces having different inclination angles and divided in a direction perpendicular to the dividing direction of the reflecting surface of the first S and reflecting section.

この他、本発明の特徴は実施例において記載されている
。Other features of the invention are described in the Examples.

（実り’ｔｓ例） 第１図（Ａ）　、　（Ｂ）は本発明の一実施例の光学系
の概略図である。同図（八）は平面図、同図（Ｂ）は正
面図である。図中ｌはＷｌをレンズ、２は撮影レンズ１
の射出瞳、３は撮影レンズ１のｐ定結像面、４はフィー
ルドレンズ、５は視野マスク、６は１り結像系て第２図
にその斜視図を示す。再結像系６は１対の１」結像レン
ズトＩＩ　、　６−２１と２つの反射面６−１２１．６
−２２１より成る第１反射部と２つの反射面６−１２２
．６−２２２より成る第２反射部を有している。７は再
結像レンズ６−１１　、６−２１の両方に配置した２つ
の開］１をイＪする絞り、８は受光手段で同−手向Ｅに
２つの受光素４列８−１．８−２を有している。２つの
受光素子列８−１．８−２は第１図（Ｃ）に示すように
Ｙ４ｉ［ｋに対し上下方向に２つに分離して構成されて
いる。(Example of fruitfulness) FIGS. 1A and 1B are schematic diagrams of an optical system according to an embodiment of the present invention. Figure (8) is a plan view, and Figure (B) is a front view. In the figure, l is the lens Wl, and 2 is the photographing lens 1.
2 is a perspective view of the exit pupil, 3 is the p constant imaging plane of the photographing lens 1, 4 is the field lens, 5 is the field mask, and 6 is the single imaging system. The reimaging system 6 includes a pair of 1'' imaging lenses II, 6-21 and two reflective surfaces 6-121.6.
- The first reflecting section consisting of 221 and two reflecting surfaces 6-122
．． 6-222. Reference numeral 7 indicates two apertures disposed on both the re-imaging lenses 6-11 and 6-21, and 8 indicates a light receiving means, which includes four rows of two light receiving elements 8-1. 8-2. The two light-receiving element arrays 8-1 and 8-2 are configured to be separated into two in the vertical direction with respect to Y4i[k, as shown in FIG. 1(C).

本実施例ではフィールドレンズ４により再結像レンズ６
−１１　、６−２１の瞳と撮影レンズ１の射出瞳２とが
略共役関係となるように構成し、撮影レンズ１の射黒瞳
２を２つの領域２ａ　、　２ｂに分割している。In this embodiment, the re-imaging lens 6 is formed by the field lens 4.
-11 and 6-21 and the exit pupil 2 of the photographic lens 1 are configured to have a substantially conjugate relationship, and the exit pupil 2 of the photographic lens 1 is divided into two regions 2a and 2b.

撮影レンズ１を通過した被写体からの光束はｒ定結像面
３近傍−に第１次物体像を形成する。第１次物体像のう
ち撮影レンズ１の射出瞳２の一方の領域２ａを通過した
光束り、は再結像レンズ６−１１に入射し、２つの反射
面ト・１２１．８−１２２で反射し、受光素ｆ゛列８−
１上に第２次物体像を形成す。The light flux from the subject that has passed through the photographic lens 1 forms a primary object image near the r-regular imaging plane 3. The light flux that has passed through one area 2a of the exit pupil 2 of the photographing lens 1 in the primary object image enters the re-imaging lens 6-11 and is reflected by the two reflective surfaces 121.8-122. Then, the photodetector f′ array 8-
A secondary object image is formed on 1.

る。同様に射出瞳２の他方の領域２ｂを通過した光束１
，２は再結像レンズト２１に入射し、２つの　゛反射面
ｔｉ−２２１，１ｉ−２２２で反射し、受光素子列８−
２上に第２次物体像を形成する。Ru. Similarly, the light beam 1 that has passed through the other region 2b of the exit pupil 2
.
A secondary object image is formed on 2.

２つの第２次物体像の受光素子列。Ｌの相対的位置はＷ
ｔ影レしズｌの航ビン又は後ピン等の合焦状態とディフ
ォーカス量の大小により受光素子列８−１．８−２の矢
印Ｇ−１，Ｃ−２で示す方向の横ずれがとなって現われ
る。焦点検出はこのときの２つの第２次物体像の相対的
位置関係を受光手段８で検出することにより行っている
。Light receiving element array for two secondary object images. The relative position of L is W
Depending on the in-focus state of the front focus or rear focus of the shadow lens l and the magnitude of the defocus amount, lateral deviation in the directions shown by arrows G-1 and C-2 of the light-receiving element array 8-1.8-2 occurs. It appears. Focus detection is performed by detecting the relative positional relationship between the two secondary object images using the light receiving means 8 at this time.

本実施例では再結像系６の第１反射部と第２反射部の４
つの反射面の角度を適切に設定することにより２′つの
第２次物体像を射出瞳２の分割方向とは川向方向、即ち
上下方向に分割して各々の受光素４列８−Ｌ、　８−２
上に再結像されている。In this embodiment, the first reflecting section and the second reflecting section of the re-imaging system 6 are
By appropriately setting the angles of the two reflecting surfaces, the exit pupil 2 is divided into 2' secondary object images in the river direction, that is, in the vertical direction, and each of the four rows of light-receiving elements 8-L, 8 is divided. -2
It is reimaged above.

即ち本実施例では第１反射部の傾角の異なる２つの反射
面６−１２１．６−２２１の分割方向と直交する方向に
第２反射部の２つの反射面６−１２２．６−２２２を傾
角な異ならしめて分割して配置している。これにより２
つの再結像レンズ６−１１　、６−２１のうち例えば再
結像レンズ６−１１を通過した光束が第１反射部の反射
面６−１２１で反射した後、第２反射部の反射面６−１
２２のみで反射し、他の反射面６−２２２に入射し、光
束が混合しないようにして第２次物体像の光学性能を良
好に維持している。That is, in this embodiment, the two reflecting surfaces 6-122.6-222 of the second reflecting section are tilted in a direction perpendicular to the dividing direction of the two reflecting surfaces 6-121.6-221 of the first reflecting section having different inclination angles. They are divided and arranged according to their differences. This results in 2
Of the two re-imaging lenses 6-11 and 6-21, for example, after the light beam that has passed through the re-imaging lens 6-11 is reflected on the reflective surface 6-121 of the first reflective section, the light beam passes through the reflective surface 6-121 of the second reflective section. -1
22 and enters the other reflecting surface 6-222 to prevent the light beams from mixing, thereby maintaining good optical performance of the secondary object image.

１奮１結像レンズ６−１１から２つの反射面６−１２１
゜６−１２２を介して受光素子列８−１に至る光路長と
再結像レンズ６−２１から２つの反射面６−２２１゜６
−２２２を介して受光素子列８−２に至る光路長とは略
等しくなるようにしている。Two reflective surfaces 6-121 from one imaging lens 6-11
The optical path length from the re-imaging lens 6-21 to the light-receiving element array 8-1 via 6-122 and the two reflecting surfaces 6-221 6
-222 to the light receiving element array 8-2.

本実施例では受光素子列８−１．８−２に入射する主光
線が略平行となるように各反射面を設定し構成の簡素化
を図っている。In this embodiment, each reflecting surface is set so that the principal rays incident on the light receiving element rows 8-1, 8-2 are substantially parallel to simplify the configuration.

以トのように本実施例では従来のように再結像系に光束
を上下方向に分離する手段としてプリズムを用いた代わ
りに反射部材を用いることによりプリズムから発生する
収差の影響を除去し、良好なる光学性能を存した第２次
物体像を受光手段面上に形成している。これにより常に
高精度な焦点検出を可能としている。As described above, in this embodiment, instead of using a prism as a means for vertically separating the luminous flux in the re-imaging system as in the past, a reflecting member is used to eliminate the influence of aberrations generated from the prism. A secondary object image with good optical performance is formed on the surface of the light receiving means. This enables highly accurate focus detection at all times.

尚、本実施例においては２つの受光素ｆ・列８−１　、
８−２は第１図（Ｃ）の実線で示す寸法を有するもので
あるが、２つの受光Ｊ　ｒ−列を上下方向平行となるよ
うに配置しているので同図の点線で示す横方向に延長し
た寸法で構成しても良い。受光素ｒ−列の長さを延長す
れば大きなディフォーカス）辻の検出が可能となり焦点
検出範囲を拡大することができる。In this embodiment, two light receiving elements f/column 8-1,
8-2 has the dimensions shown by the solid line in Fig. 1(C), but since the two light-receiving columns are arranged vertically parallel to each other, the lateral direction shown by the dotted line in the figure It may also be configured with dimensions extended to . If the length of the r-array of light receiving elements is extended, it becomes possible to detect large defocus points, and the focus detection range can be expanded.

４つの反射面６−１２１　、６−２２１　、６−１２２
　、６−２２２は各々４つの反射鏡で構成しても良く、
又は１つのプラスチック若しくはガラスモールド等のブ
ロック材で構成しても良い。更にこのブロック材と２つ
の再結像レンズ６−１１　、６−２１とを一体化して構
成しても良い。Four reflective surfaces 6-121, 6-221, 6-122
, 6-222 may each be composed of four reflecting mirrors,
Alternatively, it may be constructed from a block material such as a single plastic or glass mold. Furthermore, this block material and the two re-imaging lenses 6-11 and 6-21 may be integrated.

本実ｈＫ例においては２つの再結像レンズを用いた場合
を示したが、再結像レンズを１つとし、絞り７の２つの
開［１を含むように構成して撮影レンズ１の射出瞳２を
２つの領域に分割するようにしても良い。In this actual hK example, a case was shown in which two re-imaging lenses were used, but by using one re-imaging lens and configuring the diaphragm 7 to include two apertures [1], the exit of the photographing lens 1 is The pupil 2 may be divided into two regions.

（発明の効果） 本発明によれば再結像系に所定形状の反射面を有した第
１．第２反射部を用いることにより２つの第２次物体像
を上下方向に各々分離し、受光素子列Ｆに良好なる光学
性能を有して形成することができ、ディフォーカス範囲
を拡大した高精度の焦点検出が可能な焦点検出装置を達
成することが　　　　□できる。(Effects of the Invention) According to the present invention, the reimaging system includes a first mirror having a reflecting surface of a predetermined shape. By using the second reflection section, two secondary object images can be separated in the vertical direction and formed with good optical performance on the light receiving element array F, resulting in high precision with an expanded defocus range. It is possible to achieve a focus detection device capable of detecting a focus of □.

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

第１図（Ａ）　、　（［１）は各々本発明の一実施例の
光学系の平面図と正面図、第１図（Ｃ）は第１図（Ａ）
の一部分の受光り段の説明図、第２図は本発明のｉ１Ｇ
結像系の一実施例の斜視図である。図中１は撮影レンズ
、２は射出瞳、３は子定結像面、４はフィールドレンズ
、５は視野マスク、６は再結像系、７は絞り、６−１１
．６−２１は各Ｑ再結゛像レンズ、８−１　、８−２は
各々受光素子・列、８は受光手段−１６−１２１、６−
２２１は第１反射部、　６−１２２　、６−２２２は第
２反射部である。Figures 1(A) and ([1) are respectively a plan view and a front view of an optical system according to an embodiment of the present invention, and Figure 1(C) is Figure 1(A).
FIG. 2 is an explanatory diagram of a part of the light receiving stage of the i1G of the present invention.
FIG. 2 is a perspective view of an embodiment of an imaging system. In the figure, 1 is a photographing lens, 2 is an exit pupil, 3 is a fixed imaging plane, 4 is a field lens, 5 is a field mask, 6 is a reimaging system, 7 is an aperture, 6-11
．． 6-21 is each Q refocusing lens, 8-1 and 8-2 are each a light receiving element/row, and 8 is a light receiving means -16-121, 6-
221 is a first reflecting section, and 6-122 and 6-222 are second reflecting sections.

Claims (1)

【特許請求の範囲】[Claims] 撮影レンズの像面側に前記撮影レンズの瞳を２つの領域
に分割し、分割した２つの瞳領域を通過する光束から各
々第２次物体像を形成する再結像系を配置し、前記再結
像系の像面近傍に２つの受光素子列より成る受光手段を
配置し、前記受光手段により前記２つの第２次物体像の
相対的位置関係を検出することにより前記撮影レンズの
焦点状態を検出する焦点検出装置において、前記再結像
系は再結像レンズと該再結像レンズを通過した光束を前
記２つの受光素子列に各々導光する為の傾角を異にした
２つの反射面より成る第１反射部と該第１反射部の反射
面の分割方向と直交する方向に分割した傾角の異なる２
つの反射面より成る第２反射部とを有していることを特
徴とする焦点検出装置。A re-imaging system that divides the pupil of the photographic lens into two regions and forms a secondary object image from each of the light beams passing through the two divided pupil regions is disposed on the image plane side of the photographic lens. A light receiving means consisting of two light receiving element arrays is arranged near the image plane of the imaging system, and the focus state of the photographing lens is determined by detecting the relative positional relationship between the two secondary object images using the light receiving means. In the focus detection device, the re-imaging system includes a re-imaging lens and two reflecting surfaces with different inclinations for guiding the light beams that have passed through the re-imaging lens to the two light receiving element arrays. A first reflecting part consisting of a first reflecting part and two parts having different inclination angles divided in a direction orthogonal to the dividing direction of the reflecting surface of the first reflecting part.
1. A focus detection device comprising: a second reflecting section consisting of two reflecting surfaces.