JPH08220422A - Focus detector - Google Patents
Focus detectorInfo
- Publication number
- JPH08220422A JPH08220422A JP7027161A JP2716195A JPH08220422A JP H08220422 A JPH08220422 A JP H08220422A JP 7027161 A JP7027161 A JP 7027161A JP 2716195 A JP2716195 A JP 2716195A JP H08220422 A JPH08220422 A JP H08220422A
- Authority
- JP
- Japan
- Prior art keywords
- focus detection
- pattern
- opaque
- detection device
- projection
- 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
Links
Landscapes
- Automatic Focus Adjustment (AREA)
- Focusing (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、投射光学系により被写
体に投射して焦点検出を行なうアクティブ型の焦点検出
装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active focus detecting apparatus which detects a focus by projecting an object by a projection optical system.
【０００２】[0002]
【従来の技術】一般にレンズ交換式のカメラでは、多種
類の交換レンズに対応するため撮影レンズを通過した外
界からの光を利用して焦点検出を行う、いわゆるパッシ
ブ型の焦点検出装置が主流となっている。しかし、この
ようなパッシブ型の焦点検出装置では、外界が暗い時や
被写体のコントラストが低い時には焦点検出が困難ある
いは不能になる。このようなパッシブ型の欠点を解決す
るため、所定の照明装置から補助光を投射して焦点検出
を行うアクティブ型の焦点検出装置が知られている（例
えば、特開昭６１−１３８２２２号公報参照）。2. Description of the Related Art Generally, in the interchangeable lens type camera, a so-called passive type focus detecting device is mainly used to detect a focus by using light from the outside world that has passed through a photographing lens in order to support various kinds of interchangeable lenses. Has become. However, in such a passive focus detection device, focus detection is difficult or impossible when the external environment is dark or the contrast of the subject is low. In order to solve such a defect of the passive type, an active type focus detecting device is known in which auxiliary light is projected from a predetermined illuminating device to perform focus detection (for example, see JP-A-61-138222). ).
【０００３】図５はアクティブ型の焦点検出装置を備え
たカメラの横断面図である。このカメラでは、撮影レン
ズ７０１を通過した被写体からの光束は、メインミラー
７０２の透光部を通過してサブミラー７０３で下方に反
射され、焦点検出ユニット７０４へ入射する。一方、カ
メラ７０５の上面に設けられたアクセサリーシュー７０
６には閃光装置７０７が装着され、この閃光装置７０７
内には投影光源７０８、投影パターンフィルム７０９、
投射レンズ７１０を有する投射光学系７１１が設置され
ている。外界が暗い時や被写体のコントラストが低い時
には、投影光源７０８から例えば赤外光が発光され、投
影パターンフィルム７０９と投射レンズ７１０を通り、
被写体に投影パターンフィルム７０９の投影パターン像
が投射される。その反射光は撮影レンズ７１０とミラー
７０２，７０３を介して例えば公知の位相差方式の焦点
検出部７０４へ入射し、撮影レンズ７０１の焦点調節状
態が検出される。FIG. 5 is a cross-sectional view of a camera equipped with an active focus detection device. In this camera, the light flux from the subject that has passed through the taking lens 701 passes through the transparent portion of the main mirror 702, is reflected downward by the sub mirror 703, and is incident on the focus detection unit 704. On the other hand, the accessory shoe 70 provided on the upper surface of the camera 705
6 is equipped with a flash device 707.
A projection light source 708, a projection pattern film 709,
A projection optical system 711 having a projection lens 710 is installed. When the external environment is dark or the contrast of the subject is low, for example, infrared light is emitted from the projection light source 708, passes through the projection pattern film 709 and the projection lens 710,
The projection pattern image of the projection pattern film 709 is projected on the subject. The reflected light enters the focus detection unit 704 of, for example, a known phase difference method via the taking lens 710 and the mirrors 702 and 703, and the focus adjustment state of the taking lens 701 is detected.
【０００４】図６は位相差方式による焦点検出の原理を
示す。図において、８０１はフィルム面と等価な撮影レ
ンズ７０１の予定結像面であり、８０２はコンデンサー
レンズ８０３と一対の再結像レンズ８０４，８０５を有
する焦点検出光学系に対して予定結像面８０１と共役な
面である。撮影レンズ７０１により予定結像面８０１上
に形成された前ピン像Ａ、合焦像Ｂおよび後ピン像Ｃ
は、コンデンサーレンズ８０３と一対の再結像レンズ８
０４，８０５によって予定結像面８０２上にそれぞれ第
１の像Ａ１，Ｂ１，Ｃ１および第２の像Ａ２，Ｂ２，Ｃ
２として再結像される。ここで、第１と第２の像の間隔
は撮影レンズ７０１の焦点調節状態によって変化する。
したがって、予定結像面８０２あるいはその近傍にＣＣ
Ｄなどの光電変換器８０６を配置し、その出力に基づい
て第１と第２の像が最もよく一致するときの２像の間隔
を求め、その像間隔に基づいて撮影レンズ７０１の焦点
調節状態を検出することができる。なお、図６におい
て、８０７は撮影レンズの光軸、８０８は一対の絞り開
口を再結像レンズ８０４，８０５の直前に形成するため
の絞りマスクである。FIG. 6 shows the principle of focus detection by the phase difference method. In the figure, 801 is a planned image forming surface of the taking lens 701 equivalent to a film surface, and 802 is a planned image forming surface 801 for a focus detection optical system having a condenser lens 803 and a pair of re-imaging lenses 804 and 805. It is a surface conjugate with. The front focus image A, the in-focus image B, and the rear focus image C formed on the expected image forming surface 801 by the taking lens 701.
Is a condenser lens 803 and a pair of re-imaging lenses 8
04 and 805, the first image A1, B1, C1 and the second image A2, B2, C are respectively formed on the planned image forming surface 802.
It is re-imaged as 2. Here, the interval between the first and second images changes depending on the focus adjustment state of the taking lens 701.
Therefore, the CC may be formed on the planned image plane 802 or in the vicinity thereof.
A photoelectric converter 806 such as D is arranged, the distance between the two images when the first and second images best match each other is obtained based on the output, and the focus adjustment state of the photographing lens 701 is determined based on the image distance. Can be detected. In FIG. 6, reference numeral 807 is an optical axis of the photographing lens, and 808 is an aperture mask for forming a pair of aperture openings immediately before the re-imaging lenses 804 and 805.
【０００５】図７は、従来の焦点検出装置の投影パター
ンフィルム７０９のパターンの一例を示す。従来の投影
パターンでは、不透明部６０１の幅ｐ、透明部６０２の
幅ｑおよびそれらの繰り返し周期（ｐ＋ｑ）が全く不規
則に形成されている。これは、位相差方式の焦点検出装
置に同一幅の不透明部６０１を複数個設けると、再結像
レンズ８０４，８０５により形成される２つの投影パタ
ーン像の一致する組が複数組検出されることになり、焦
点検出を誤ることになるからである。FIG. 7 shows an example of a pattern of a projection pattern film 709 of a conventional focus detection device. In the conventional projection pattern, the width p of the opaque portion 601, the width q of the transparent portion 602, and their repeating period (p + q) are formed irregularly. This is because when a plurality of opaque parts 601 having the same width are provided in the phase difference type focus detection device, a plurality of sets in which two projection pattern images formed by the re-imaging lenses 804 and 805 coincide with each other are detected. This is because the focus detection is erroneous.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、従来の
焦点検出装置では、投影パターンフィルムの不透明部の
幅と透明部の幅がそれぞれの部分で異なり、その繰り返
し周期も全く不規則に形成されているので、次のような
問題がある。例えばＣＣＤなどの光電変換器上に、不規
則で単数または複数の不透明部と透明部の投影パターン
像が形成されている場合、不透明部が大きかったり小さ
かったりするので、ＣＣＤ内に照明される部分が大きい
場合と小さい場合が発生し、複数のＣＣＤの出力が異な
り、焦点検出に誤りが生じる可能性がある。また、不透
明部の幅と透明部の幅を不規則に配列すると投影パター
ンフィルムの製造が困難になるという問題がある。However, in the conventional focus detection device, the width of the opaque portion and the width of the transparent portion of the projection pattern film are different in each portion, and the repetition cycle thereof is also irregular. Therefore, there are the following problems. For example, when a projection pattern image of one or more opaque parts and transparent parts is irregularly formed on a photoelectric converter such as a CCD, the opaque parts may be large or small, so that the part illuminated in the CCD. There is a case where is large and a case where is small, outputs of a plurality of CCDs are different, and an error may occur in focus detection. Further, if the widths of the opaque portions and the transparent portions are irregularly arranged, it is difficult to manufacture the projection pattern film.
【０００７】さらに、焦点検出領域を分割して焦点検出
を行なう焦点検出装置では、分割した各焦点検出領域の
ＣＣＤには互いに異なる投影パターン像が入力され、そ
れぞれのＣＣＤの出力が異なり、焦点検出に誤りが生じ
る。Further, in a focus detection device which divides the focus detection area to perform focus detection, different projection pattern images are input to the CCDs of the respective divided focus detection areas, the outputs of the respective CCDs differ, and focus detection is performed. Error occurs.
【０００８】さらにまた、光軸外に焦点検出領域を有す
る焦点検出装置では次のような問題がある。通常、焦点
検出にともなう撮影レンズの駆動は合焦するまでに複数
回行なわれる。焦点検出領域が光軸上にある場合は、レ
ンズ駆動前後でＣＣＤに入力される投影パターン像はあ
まり変らない。しかし、焦点検出領域が光軸外にある場
合は、レンズ駆動前後でＣＣＤに入力される投影パター
ン像が変化する。このような光軸外に焦点検出領域を有
する焦点検出装置に、従来のような不透明部と透明部が
不規則に配列された投影パターンフィルムを用いると、
レンズ駆動前後でＣＣＤに異なった投影パターン像が入
力され、レンズ駆動前後でＣＣＤの出力も異なり、焦点
検出に誤りが生じる。Furthermore, the focus detection device having a focus detection area outside the optical axis has the following problems. Usually, the driving of the photographing lens associated with focus detection is performed a plurality of times before focusing. When the focus detection area is on the optical axis, the projection pattern image input to the CCD before and after driving the lens does not change much. However, when the focus detection area is outside the optical axis, the projection pattern image input to the CCD changes before and after driving the lens. In such a focus detection device having a focus detection area off the optical axis, using a projection pattern film in which opaque portions and transparent portions are irregularly arranged as in the conventional case,
Different projection pattern images are input to the CCD before and after driving the lens, and the output of the CCD also changes before and after driving the lens, resulting in an error in focus detection.
【０００９】複数の焦点検出領域を有する焦点検出装置
でも、複数の焦点検出領域のＣＣＤに投影パターン像が
入力され、これらの焦点検出領域がすべて同一距離にあ
る同一の被写体を捕捉している場合でも、従来のような
不透明部と透明部が不規則に配列された投影パターンフ
ィルムを用いると、それぞれのＣＣＤに互いに異なる投
影パターン像が入力され、それぞれのＣＣＤの出力も異
なり、同一距離の同一被写体とは認識されず、焦点検出
に誤りが生じる。Even in a focus detection device having a plurality of focus detection areas, the projection pattern images are input to the CCDs of the plurality of focus detection areas, and all the focus detection areas capture the same subject at the same distance. However, if a conventional projection pattern film in which opaque parts and transparent parts are irregularly arranged is used, different projection pattern images are input to the respective CCDs, the outputs of the respective CCDs are different, and the same distance is the same. The object is not recognized, and the focus detection is erroneous.
【００１０】本発明の目的は、焦点検出の誤りが発生し
ないパターンの投影パターンフィルムを有する焦点検出
装置を提供することにある。It is an object of the present invention to provide a focus detection device having a projection pattern film having a pattern in which focus detection error does not occur.
【００１１】[0011]
【課題を解決するための手段】上記目的を達成するため
に、請求項１の発明は、投影光源と投影パターンフィル
ムと投射レンズとを有する投射光学系により被写体に補
助光を投射し、焦点検出光学系により撮影レンズを通過
した被写体からの一対の光束を光電変換器上に導いて一
対の被写体像を結像し、前記一対の被写体像の像ずれ量
に基づいて前記撮影レンズの焦点調節状態を検出する焦
点検出装置に適用され、前記投影パターンフィルムのパ
ターンは複数の不透明部と透明部を周期的に配列した。
請求項２の焦点検出装置は、前記パターンを、各不透明
部とそれらの不透明部の配列方向の特定側に隣接する透
明部とを１組とし、各組の不透明部の幅と透明部の幅と
の和が等しくなるように形成したものである。請求項３
の焦点検出装置は、前記パターンを、各不透明部とそれ
らの不透明部の配列方向の特定側に隣接する透明部とを
１組とし、各組の不透明部の幅と透明部の幅とが等しく
なるように形成したものである。請求項４の焦点検出装
置の前記撮影レンズは短焦点レンズであり、前記光電変
換器上に結像される前記パターンの像の周期が前記一対
の被写体像の像ずれ量を検出する際の最大像ずらし量よ
りも大きくなるように前記パターンの周期を設定したも
のである。請求項５の焦点検出装置の前記撮影レンズは
長焦点レンズであり、前記パターンの周期を前記光電変
換器上に結像された前記パターンの像の範囲よりも大き
くしたものである。請求項６の焦点検出装置は、前記投
射光学系をカメラの外部に取り付けたものである。請求
項７の焦点検出装置は、前記投射光学系をカメラに内蔵
したものである。In order to achieve the above object, the invention of claim 1 projects focus light by projecting auxiliary light onto a subject by a projection optical system having a projection light source, a projection pattern film and a projection lens. An optical system guides a pair of light fluxes from the subject that have passed through the taking lens onto a photoelectric converter to form a pair of subject images, and a focus adjustment state of the taking lens based on an image shift amount of the pair of subject images. The projection pattern film pattern has a plurality of opaque parts and transparent parts arranged periodically.
The focus detection device according to claim 2, wherein the pattern includes each opaque portion and a transparent portion adjacent to a specific side of the opaque portions in the arrangement direction as one set, and the width of the opaque portion and the width of the transparent portion of each set. It is formed so that the sum of and becomes equal. Claim 3
In the focus detection device, the opaque portion and the transparent portion adjacent to the opaque portion on the specific side in the arrangement direction are set as one set, and the width of the opaque portion and the width of the transparent portion of each set are equal. It is formed so that. The photographing lens of the focus detection device according to claim 4, wherein the photographing lens is a short-focus lens, and a cycle of images of the pattern formed on the photoelectric converter is maximum when detecting an image shift amount of the pair of subject images. The cycle of the pattern is set so as to be larger than the image shift amount. The photographing lens of the focus detection device according to claim 5 is a long focus lens, and the period of the pattern is made larger than the range of the image of the pattern formed on the photoelectric converter. According to a sixth aspect of the focus detection apparatus, the projection optical system is attached to the outside of the camera. According to a seventh aspect of the present invention, there is provided a focus detection device in which the projection optical system is built in a camera.
【００１２】[0012]
【作用】請求項１の焦点検出装置では、複数の不透明部
と透明部を周期的に配列したパターンの投影パターンフ
ィルムを用いた投射光学系により被写体に補助光を投射
し、焦点検出光学系により撮影レンズを通過した被写体
からの一対の光束を光電変換器上に導いて一対の被写体
像を結像し、一対の被写体像の像ずれ量に基づいて撮影
レンズの焦点調節状態を検出する。請求項２の焦点検出
装置では、各不透明部とそれらの不透明部の配列方向の
特定側に隣接する透明部とを１組とし、各組の不透明部
の幅と透明部の幅との和が等しくなるように形成したパ
ターンの投影パターンフィルムを用いた投射光学系によ
り被写体に補助光を投射し、請求項１の手順と同様に撮
影レンズの焦点調節状態を検出する。請求項３の焦点検
出装置では、各不透明部とそれらの不透明部の配列方向
の特定側に隣接する透明部とを１組とし、各組の不透明
部の幅と透明部の幅とが等しくなるように形成したパタ
ーンの投影パターンフィルムを用いた投射光学系により
被写体に補助光を投射し、請求項１の手順と同様に撮影
レンズの焦点調節状態を検出する。In the focus detecting apparatus according to the first aspect of the present invention, the auxiliary light is projected onto the subject by the projection optical system using the projection pattern film having a pattern in which a plurality of opaque portions and transparent portions are periodically arranged, and the focus detecting optical system is used. A pair of light fluxes from the subject that have passed through the taking lens are guided onto a photoelectric converter to form a pair of subject images, and the focus adjustment state of the taking lens is detected based on the image shift amount of the pair of subject images. According to another aspect of the focus detection device of the present invention, each opaque portion and the transparent portion adjacent to the specific side in the arrangement direction of the opaque portions are set as one set, and the sum of the width of the opaque portion and the width of the transparent portion of each set is set. Auxiliary light is projected onto a subject by a projection optical system using a projection pattern film having a pattern formed to be equal to each other, and the focus adjustment state of the taking lens is detected in the same manner as in the procedure of claim 1. According to another aspect of the focus detection device of the present invention, each opaque portion and the transparent portion adjacent to the opaque portion on the specific side in the arrangement direction are set as one set, and the width of the opaque portion and the width of the transparent portion of each set are equal. The projection optical system using the projection pattern film having the pattern thus formed projects the auxiliary light on the subject, and the focus adjustment state of the taking lens is detected in the same manner as the procedure of claim 1.
【００１３】[0013]
【実施例】図１〜図４により本発明の焦点検出装置の実
施例を説明する。なお、実施例の焦点検出装置とその焦
点検出装置を備えたカメラの構成は図５および図６に示
すものと同様であり、それらの図を参照しながら本発明
の実施例を説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the focus detecting device of the present invention will be described with reference to FIGS. Note that the configurations of the focus detection device of the embodiment and the camera including the focus detection device are the same as those shown in FIGS. 5 and 6, and an embodiment of the present invention will be described with reference to these drawings.
【００１４】図１は一実施例の投影パターンフィルム７
０９Ａを示す。このフィルム７０９Ａのパターンは、複
数の不透明部と透明部を一定の規則にしたがって周期的
に配列したものである。つまり、不透明部１０１、透明
部１０２、不透明部１０３、透明部１０４、不透明部１
０５、透明部１０６をそれぞれ幅１：２：３：１：２：
３の比率で形成し、周期Ｌ１で周期的に配列する。な
お、図１では１周期分の配列パターンの不透明部と透明
部に対してそれぞれ符号を付して説明したが、他の組の
配列パターンも同様であり、符号とその説明を省略す
る。FIG. 1 shows a projection pattern film 7 according to one embodiment.
09A is shown. The pattern of the film 709A is such that a plurality of opaque portions and transparent portions are periodically arranged according to a certain rule. That is, the opaque portion 101, the transparent portion 102, the opaque portion 103, the transparent portion 104, and the opaque portion 1
05, the transparent portion 106 width 1: 2: 3: 1: 2:
They are formed at a ratio of 3 and are periodically arranged at a cycle L1. In FIG. 1, the opaque part and the transparent part of the array pattern for one period are described by assigning the reference numerals respectively, but the same applies to the array patterns of other sets, and the reference numerals and the description thereof are omitted.
【００１５】図２は一実施例の投影パターンフィルム７
０９Ｂを示す。このフィルム７０９Ｂのパターンは、不
透明部の幅ｐと透明部の幅ｑを一定の規則にしたがって
設定するとともに、複数の不透明部と透明部を周期的に
配列したものである。つまり、各不透明部とそれらの不
透明部の配列方向の特定側（図では右側）に隣接する透
明部とを１組とし、各組の不透明部の幅ｐと透明部の幅
ｑとの和（ｐ＋ｑ）がすべて等しくなるように設定する
とともに、不透明部２０１、透明部２０２、不透明部２
０３、透明部２０４、不透明部２０５、透明部２０６、
不透明部２０７、透明部２０８をそれぞれ幅２：３：
１：４：３：２：４：１の比率で形成し、周期Ｌ２で周
期的に配列する。なお、図２では１周期分の配列パター
ンの不透明部と透明部に対してそれぞれ符号を付して説
明したが、他の組の配列パターンも同様であり、符号と
説明を省略する。FIG. 2 shows a projection pattern film 7 according to one embodiment.
09B is shown. In the pattern of the film 709B, the width p of the opaque portion and the width q of the transparent portion are set according to a certain rule, and a plurality of opaque portions and transparent portions are periodically arranged. That is, each opaque part and a transparent part adjacent to the specific side (the right side in the drawing) in the arrangement direction of the opaque parts are set as one set, and the sum of the width p of the opaque part and the width q of the transparent part of each set ( p + q) are set to be equal to each other, and the opaque portion 201, the transparent portion 202, and the opaque portion 2 are set.
03, transparent part 204, opaque part 205, transparent part 206,
The opaque portion 207 and the transparent portion 208 have a width of 2: 3:
They are formed at a ratio of 1: 4: 3: 2: 4: 1 and are periodically arranged at a period L2. In FIG. 2, the opaque portion and the transparent portion of the array pattern for one period are described by assigning the reference numerals respectively, but the same applies to the array patterns of other sets, and the reference numerals and the description are omitted.
【００１６】図３は一実施例の投影パターンフィルム７
０９Ｃを示す。このフィルム７０９Ｃのパターンは、不
透明部の幅ｐと透明部の幅ｑを一定の規則にしたがって
設定するとともに、複数の不透明部と透明部を周期的に
配列したものである。つまり、各不透明部とそれらの不
透明部の配列方向の特定側（図では右側）に隣接する透
明部とを１組とし、各組の不透明部の幅ｐと透明部の幅
ｑとが等しくなるように設定するとともに、不透明部３
０１、透明部３０２、不透明部３０３、透明部３０４、
不透明部３０５、透明部３０６をそれぞれ３：３：２：
２：１：１の比率で形成し、周期Ｌ３で周期的に配列す
る。なお、図３では１周期分の配列パターンの不透明部
と透明部に対してそれぞれ符号を付して説明したが、他
の組の配列パターンも同様であり、符号と説明を省略す
る。FIG. 3 shows a projection pattern film 7 of one embodiment.
09C is shown. The pattern of the film 709C is such that the width p of the opaque portion and the width q of the transparent portion are set according to a certain rule, and a plurality of opaque portions and transparent portions are periodically arranged. That is, each opaque part and a transparent part adjacent to the specific side (right side in the drawing) in the arrangement direction of the opaque parts are set as one set, and the width p of the opaque part and the width q of the transparent part of each set are equal. And the opaque section 3
01, transparent portion 302, opaque portion 303, transparent portion 304,
The opaque part 305 and the transparent part 306 are 3: 3: 2:
They are formed at a ratio of 2: 1: 1 and are periodically arranged at a cycle L3. In FIG. 3, the opaque portion and the transparent portion of the array pattern for one period are described by assigning the reference numerals respectively, but the same applies to the array patterns of other sets, and the reference numerals and the description are omitted.
【００１７】上述した図１〜図３に示すフィルム７０９
Ａ〜７０９Ｃのパターンはそれぞれ周期Ｌ１，Ｌ２，Ｌ
３で周期的に配列されているので、これら周期性のパタ
ーンを有する投影パターンフィルムを用いれば焦点検出
用の光電変換器の出力が安定し、焦点検出の誤りがなく
なるとともに、容易に投影パターンフィルムの製造が可
能となる。これらの投影パターンフィルムは、例えば図
５に示すように、投射光学系７１１の投射レンズ７１０
の一方の焦点位置近くに配置され、投射レンズ７１０は
それらの投影パターン像を被写体上に投射し、投影光源
７０８、例えば発光ダイオードからの光での照明により
被写体上のコントラストが小さくなっても、その被写体
上に投影パターン像によるコントラストを作り出す。こ
れにより、焦点検出が困難または不能となる問題が解決
され、焦点検出が可能となる。The film 709 shown in FIGS. 1 to 3 described above.
The patterns of A to 709C are cycles L1, L2, L, respectively.
Since the projection pattern film having these periodic patterns is used, the output of the photoelectric converter for focus detection becomes stable, the error of focus detection is eliminated, and the projection pattern film is easily arranged. Can be manufactured. These projection pattern films are, for example, as shown in FIG. 5, a projection lens 710 of a projection optical system 711.
The projection lens 710 is arranged near one of the focal positions of the two, and the projection lens 710 projects the projection pattern images on the subject. The contrast of the projected pattern image is created on the subject. This solves the problem that focus detection is difficult or impossible, and enables focus detection.
【００１８】投影パターンフィルムのパターン１周期の
幅は、次のようにして決定する。図４は、無地の被写体
に投影された１周期の投影パターン像を焦点検出面から
見た図である。図において、ｘは一次像面上の焦点検出
用の光電変換器８０６の一画素分の幅であり、ｈは投影
パターンの１周期Ｌ０の中の不特定のパターンの幅であ
る。画素幅ｘが最大のパターン幅ｈよりも大きい場合
は、投影パターン像が一画素内で移動しても光電変換器
８０６全体としては出力レベルが変化せず、したがっ
て、投影パターン像の光電変換器８０６上での位置を正
しく検出できない。一方、画素幅ｘが最大のパターン幅
ｈ以下の場合はこのような問題は発生しないが、パター
ン幅ｈが画素幅ｘに対してかなり大きくなると、パター
ンの１周期が大きくなり、投影パターン像の内の焦点検
出に用いられる部分は一部分であるからその焦点検出部
分の周期性がなくなる上に、コントラストが低下する。The width of one cycle of the pattern of the projection pattern film is determined as follows. FIG. 4 is a view of a projection pattern image of one cycle projected on a plain object as seen from the focus detection surface. In the figure, x is the width of one pixel of the photoelectric converter 806 for focus detection on the primary image plane, and h is the width of an unspecified pattern in one cycle L0 of the projection pattern. When the pixel width x is larger than the maximum pattern width h, even if the projection pattern image moves within one pixel, the output level does not change as a whole of the photoelectric converter 806, and therefore, the photoelectric converter of the projection pattern image. The position on 806 cannot be detected correctly. On the other hand, when the pixel width x is equal to or smaller than the maximum pattern width h, such a problem does not occur. However, when the pattern width h becomes considerably larger than the pixel width x, one cycle of the pattern becomes large and the projected pattern image Since the portion used for focus detection in the inside is a portion, the periodicity of the focus detection portion disappears and the contrast decreases.
【００１９】また、パターンの１周期の幅は周期性によ
る焦点検出の誤りを防ぐことを考慮しなければならず、
交換可能な撮影レンズ７０１の種類により焦点検出の誤
りを起こさない方法が異なる。すなわち、被写体に投射
された投影パターン像全体の内、焦点検出に用いられる
部分（ＣＣＤに入力される部分）は投影パターン像の一
部分のみであり、また、被写体が一定の距離にある場
合、撮影レンズの焦点検出距離により焦点検出に用いら
れる部分は大きく異なる。撮影レンズが短焦点である場
合は、至近から無限までのピントズレ量、いわゆる最大
デフォーカス量が小さいため、図６に示す位相差方式に
よる焦点検出装置の一対の再結像レンズ８０４，８０５
により形成される一対の投影パターン像のずれ量を検出
する際の最大像ずらし量も小さく、この最大像ずらし量
が光電変換器８０６上の投影パターン像の周期よりも十
分に小さければ焦点検出の誤りは起こらない。すなわち
換言すると、光電変換器８０６上に結像される投影パタ
ーン像の周期が一対の投影パターン像の像ずれ量を検出
する際の最大像ずらし量よりも大きくなるようにパター
ンの周期を設定すればよい。また、長焦点レンズの場合
は、光電変換器８０６上の投影パターン像が大きくな
り、この光電変換器８０６上に結像する投影パターン像
の範囲が、投影パターンフィルム７０９のパターンの１
周期よりも小さければ焦点検出の誤りは起こらない。す
なわち換言すると、パターンの周期を光電変換器８０６
上に結像された投影パターン像の範囲よりも大きくすれ
ばよい。このように、投影パターンフィルム７０９のパ
ターンの１周期の幅は、コントラスト低下を抑制するこ
とも考慮して焦点検出の誤りが起こらない最小値にする
のが好ましい。Further, it is necessary to consider that the width of one cycle of the pattern prevents an error in focus detection due to the periodicity.
The method of not causing an error in focus detection differs depending on the type of the interchangeable taking lens 701. That is, of the entire projection pattern image projected on the subject, the portion used for focus detection (the portion input to the CCD) is only a part of the projection pattern image, and when the subject is at a certain distance, the image is taken. The portion used for focus detection varies greatly depending on the focus detection distance of the lens. When the photographing lens has a short focus, the amount of focus shift from the closest distance to infinity, that is, the so-called maximum defocus amount is small, so that the pair of re-imaging lenses 804 and 805 of the focus detection device by the phase difference method shown in FIG.
Also, the maximum image shift amount when detecting the shift amount of the pair of projection pattern images formed by is small, and if this maximum image shift amount is sufficiently smaller than the period of the projection pattern image on the photoelectric converter 806, focus detection is performed. No mistakes will occur. That is, in other words, the pattern cycle is set so that the cycle of the projection pattern image formed on the photoelectric converter 806 is larger than the maximum image shift amount when detecting the image shift amount of the pair of projection pattern images. Good. Further, in the case of the long focus lens, the projected pattern image on the photoelectric converter 806 becomes large, and the range of the projected pattern image formed on this photoelectric converter 806 is 1 of the pattern of the projected pattern film 709.
If it is smaller than the period, no focus detection error occurs. In other words, in other words, the period of the pattern is set to the photoelectric converter 806.
It may be larger than the range of the projected pattern image formed above. As described above, it is preferable that the width of one cycle of the pattern of the projection pattern film 709 is set to a minimum value in which an error in focus detection does not occur in consideration of suppressing a decrease in contrast.
【００２０】なお、上述した実施例では投射光学系７１
１を閃光装置７０７内に設けた例を示したが、投射光学
系７１１を閃光装置７０７外に単独で設けてもよいし、
カメラ７０５に適当な取り付け部を設けてそこに取り付
けるようにしてもよい。さらに、カメラ７０５に内蔵し
てもよい。また、投影パターンフィルムのパターンは上
述した実施例に限定されない。Incidentally, in the above-mentioned embodiment, the projection optical system 71
Although the example in which 1 is provided inside the flash device 707 is shown, the projection optical system 711 may be provided outside the flash device 707 alone,
The camera 705 may be provided with an appropriate attachment part and attached thereto. Further, it may be built in the camera 705. Further, the pattern of the projection pattern film is not limited to the above-mentioned embodiment.
【００２１】[0021]
【発明の効果】以上説明したように本発明によれば、投
影パターンフィルムを、複数の不透明部と透明部を周期
的に配列したパターンとしたので、光電変換器上で投影
パターンフィルムの透明部に対応する明るい部分と不透
明部に対応する暗い部分とが周期的に並び、光電変換素
子の出力が安定して焦点検出の誤りがなくなる。また、
投影パターンフィルムの製造が容易になる。焦点検出領
域を分割して焦点検出を行なう場合にも、周期性のある
パターンの投影パターンフィルムを用いると、各分割領
域のＣＣＤに同じような投影パターン像が入力され、各
ＣＣＤの出力も同じようなものになり、焦点検出の誤り
をなくすことができる。また、光軸外に焦点検出領域を
有する場合にも、周期性のあるパターンの投影パターン
フィルムを用いると、被写体に投影されている投影パタ
ーン像全体の内、ＣＣＤに入力する部分は異なるが、周
期性によりレンズ駆動前後にＣＣＤに入力する投影パタ
ーン像は同じようなものになり、したがって、レンズ駆
動前後でのＣＣＤの出力も同じようなものになり、焦点
検出の誤りをなくすことができる。さらに、複数の焦点
検出領域を有する場合にも、周期性のあるパターンの投
影パターンフィルムを用いると、複数の焦点検出領域の
それぞれに対応する複数のＣＣＤには同じような投影パ
ターン像が入力され、複数のＣＣＤの出力も同じような
ものになり、焦点検出の誤りをなくすことができる。な
お、パターンは、各不透明部とそれらの不透明部の配列
方向の特定側に隣接する透明部とを１組とし、各組の不
透明部の幅と透明部の幅との和が等しくなるように形成
してもよいし、各不透明部とそれらの不透明部の配列方
向の特定側に隣接する透明部とを１組とし、各組の不透
明部の幅と透明部の幅とが等しくなるように形成しても
よい。撮影レンズが短焦点の場合には、光電変換器上に
結像されるパターンの像の周期が一対の被写体像の像ず
れ量を検出する際の最大像ずらし量よりも大きくなるよ
うにパターンの周期を設定し、撮影レンズが長焦点の場
合には、パターンの周期を光電変換器上に結像されたパ
ターンの像の範囲よりも大きくするようにしたので、ど
のような撮影レンズに対しても焦点検出の誤りをなくす
ことができる。As described above, according to the present invention, the projection pattern film has a pattern in which a plurality of opaque portions and transparent portions are periodically arranged. Therefore, the transparent portion of the projection pattern film is formed on the photoelectric converter. The bright portion corresponding to the line and the dark portion corresponding to the opaque portion are periodically arranged, and the output of the photoelectric conversion element is stable, and the focus detection error is eliminated. Also,
Manufacturing of the projection pattern film is facilitated. Even when focus detection is performed by dividing the focus detection area, if a projection pattern film having a periodic pattern is used, a similar projection pattern image is input to the CCD of each divided area, and the output of each CCD is also the same. This makes it possible to eliminate an error in focus detection. Further, even when the focus detection area is located off the optical axis, if a projection pattern film having a periodic pattern is used, the portion of the entire projection pattern image projected on the subject that is input to the CCD is different, Due to the periodicity, the projection pattern images input to the CCD before and after the lens is driven are similar, and therefore the CCD outputs before and after the lens are driven are also the same, and an error in focus detection can be eliminated. Further, even when the plurality of focus detection areas are provided, when a projection pattern film having a periodic pattern is used, similar projection pattern images are input to the plurality of CCDs corresponding to the plurality of focus detection areas. The outputs of a plurality of CCDs are similar to each other, and an error in focus detection can be eliminated. In the pattern, each opaque part and a transparent part adjacent to the specific side in the arrangement direction of the opaque part are set as one set, and the width of the opaque part and the width of the transparent part of each set are equal. It may be formed, and each opaque portion and a transparent portion adjacent to the specific side in the arrangement direction of the opaque portions are set as one set so that the width of the opaque portion and the width of the transparent portion of each set are equal. You may form. When the taking lens has a short focus, the pattern image formed on the photoelectric converter has a pattern period that is larger than the maximum image shift amount when detecting the image shift amount of the pair of subject images. When the cycle is set and the shooting lens has a long focus, the cycle of the pattern is set to be larger than the range of the image of the pattern formed on the photoelectric converter. Also, the error of focus detection can be eliminated.
【図１】一実施例の投影パターンフィルムのパターンを
示す図。FIG. 1 is a diagram showing a pattern of a projection pattern film of one example.
【図２】投影パターンフィルムの他のパターンを示す
図。FIG. 2 is a diagram showing another pattern of a projection pattern film.
【図３】投影パターンフィルムの他のパターンを示す
図。FIG. 3 is a diagram showing another pattern of a projection pattern film.
【図４】投影パターンフィルムのパターンの１周期の幅
の決定方法を説明する図。FIG. 4 is a diagram illustrating a method of determining a width of one cycle of a pattern on a projection pattern film.
【図５】焦点検出装置を搭載したカメラの横断面図。FIG. 5 is a cross-sectional view of a camera equipped with a focus detection device.
【図６】位相差方式による焦点検出の原理を示す図。FIG. 6 is a diagram showing a principle of focus detection by a phase difference method.
【図７】投影パターンフィルムの従来のパターンを示す
図。FIG. 7 is a diagram showing a conventional pattern of a projection pattern film.
１０１，１０３，１０５、２０１，２０３，２０５，２
０７、３０１，３０３，３０５ 不透明部 １０２，１０４，１０６，２０２，２０４，２０６，２
０８，３０２，３０４，３０６ 透明部 ７０９Ａ，７０９Ｂ，７０９Ｃ 投影パターンフィルム101, 103, 105, 201, 203, 205, 2
07, 301, 303, 305 Opaque part 102, 104, 106, 202, 204, 206, 2
08, 302, 304, 306 Transparent part 709A, 709B, 709C Projection pattern film
Claims (7)
レンズとを有する投射光学系により被写体に補助光を投
射し、焦点検出光学系により撮影レンズを通過した被写
体からの一対の光束を光電変換器上に導いて一対の被写
体像を結像し、前記一対の被写体像の像ずれ量に基づい
て前記撮影レンズの焦点調節状態を検出する焦点検出装
置において、 前記投影パターンフィルムのパターンは、複数の不透明
部と透明部を周期的に配列したものであることを特徴と
する焦点検出装置。1. A pair of light fluxes from a subject, which have passed through a photographing lens by a focus detection optical system, are projected onto auxiliary light by a projection optical system having a projection light source, a projection pattern film, and a projection lens. In the focus detection device for forming a pair of subject images by detecting the focus adjustment state of the photographing lens based on the image shift amount of the pair of subject images, the pattern of the projection pattern film has a plurality of opaque patterns. A focus detection device characterized in that a transparent portion and a transparent portion are periodically arranged.
て、 前記パターンは、各不透明部とそれらの不透明部の配列
方向の特定側に隣接する透明部とを１組とし、各組の不
透明部の幅と透明部の幅との和が等しくなるように形成
されることを特徴とする焦点検出装置。2. The focus detection device according to claim 1, wherein the pattern includes each opaque portion and a transparent portion adjacent to a specific side in the arrangement direction of the opaque portions as one set, and the opaque portion of each set. And a width of the transparent portion are equal to each other.
て、 前記パターンは、各不透明部とそれらの不透明部の配列
方向の特定側に隣接する透明部とを１組とし、各組の不
透明部の幅と透明部の幅とが等しくなるように形成され
ることを特徴とする焦点検出装置。3. The focus detection device according to claim 1, wherein the pattern includes each opaque portion and a transparent portion adjacent to a specific side of the opaque portions in a direction in which the opaque portions are arranged, and the opaque portion of each set is formed. The focus detection device is characterized in that it is formed so that the width of the transparent part is equal to the width of the transparent part.
点検出装置において、 前記撮影レンズは短焦点レンズであり、前記光電変換器
上に結像される前記パターンの像の周期が前記一対の被
写体像の像ずれ量を検出する際の最大像ずらし量よりも
大きくなるように前記パターンの周期を設定することを
特徴とする焦点検出装置。4. The focus detection device according to claim 1, wherein the taking lens is a short focus lens, and a cycle of an image of the pattern formed on the photoelectric converter is A focus detection apparatus, wherein the cycle of the pattern is set so as to be larger than a maximum image shift amount when detecting the image shift amount of the pair of subject images.
点検出装置において、 前記撮影レンズは長焦点レンズであり、前記パターンの
周期を前記光電変換器上に結像された前記パターンの像
の範囲よりも大きくすることを特徴とする焦点検出装
置。5. The focus detection device according to claim 1, wherein the taking lens is a long focus lens, and the pattern is formed on the photoelectric converter with a cycle of the pattern. The focus detection device is characterized in that it is made larger than the range of the image.
点検出装置において、 前記投射光学系をカメラの外部に取り付けることを特徴
とする焦点検出装置。6. The focus detection device according to claim 1, wherein the projection optical system is attached to the outside of the camera.
点検出装置において、 前記投射光学系をカメラに内蔵することを特徴とする焦
点検出装置。7. The focus detection device according to claim 1, wherein the projection optical system is built in a camera.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2716195A JP3674975B2 (en) | 1995-02-15 | 1995-02-15 | Focus detection device |
| US08/601,847 US5771412A (en) | 1995-02-15 | 1996-02-15 | Focus detection device and method using a projection pattern material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2716195A JP3674975B2 (en) | 1995-02-15 | 1995-02-15 | Focus detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08220422A true JPH08220422A (en) | 1996-08-30 |
| JP3674975B2 JP3674975B2 (en) | 2005-07-27 |
Family
ID=12213340
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2716195A Expired - Lifetime JP3674975B2 (en) | 1995-02-15 | 1995-02-15 | Focus detection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3674975B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010243735A (en) * | 2009-04-03 | 2010-10-28 | Nikon Corp | Focus detection device and imaging apparatus |
| US10371924B2 (en) | 2014-09-11 | 2019-08-06 | Samsung Electronics Co., Ltd. | Image device comprising fill-light projector, and autofocus method using imaging device |
-
1995
- 1995-02-15 JP JP2716195A patent/JP3674975B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010243735A (en) * | 2009-04-03 | 2010-10-28 | Nikon Corp | Focus detection device and imaging apparatus |
| US10371924B2 (en) | 2014-09-11 | 2019-08-06 | Samsung Electronics Co., Ltd. | Image device comprising fill-light projector, and autofocus method using imaging device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3674975B2 (en) | 2005-07-27 |
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