JP2007033653A - Focus detection device and imaging apparatus using the same - Google Patents

Focus detection device and imaging apparatus using the same Download PDF

Info

Publication number
JP2007033653A
JP2007033653A JP2005214514A JP2005214514A JP2007033653A JP 2007033653 A JP2007033653 A JP 2007033653A JP 2005214514 A JP2005214514 A JP 2005214514A JP 2005214514 A JP2005214514 A JP 2005214514A JP 2007033653 A JP2007033653 A JP 2007033653A
Authority
JP
Japan
Prior art keywords
focus detection
focus
values
light
light quantity
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.)
Pending
Application number
JP2005214514A
Other languages
Japanese (ja)
Inventor
Kazuto Ishida
和外 石田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP2005214514A priority Critical patent/JP2007033653A/en
Publication of JP2007033653A publication Critical patent/JP2007033653A/en
Pending legal-status Critical Current

Links

Landscapes

  • Focusing (AREA)
  • Automatic Focus Adjustment (AREA)
  • Studio Devices (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a focus detection device in which the focus adjustment state of a photographic lens is detected highly precisely by using so called an image blurring method. <P>SOLUTION: The focus detection device has: a secondary imaging system which forms a plurality of light quantity distributions of an object image by using luminous fluxes which pass through different regions of a pupil of the photographic lens; a photoelectric converter element which is provided with a plurality of pixel rows composed of a plurality of pixels and detects the plurality of light quantity distributions of the object image formed by the secondary imaging system; and a first and a second focus detection systems which derive the focusing condition of the photographic lens from the relative positions of the plurality of light quantity distributions. The chromatic aberrations of the first and the second focus detection systems are different from each other. The nature of a light source for illuminating the object is discriminated by comparing the first and the second focused values derived by correcting a first and a second detected focus values measured by the first and a second focus detection systems by a first and second correction values, and the first and the second correction values for correcting the first and the second detected focus values are varied on the basis of the discriminated result. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は焦点検出装置及びそれを用いた撮像装置に関し、特に撮影レンズ(対物レンズ)の焦点調節状態を所謂像ずれ方式(位相差検出方式)を用いて検出するようにした、例えば一眼レフレックスカメラ、一眼レフレックス電子カメラ、デジタルカメラ、そしてビデオカメラ等の撮像装置に好適なものである。   The present invention relates to a focus detection apparatus and an imaging apparatus using the same, and more particularly, to detect a focus adjustment state of a photographic lens (objective lens) using a so-called image shift method (phase difference detection method). It is suitable for imaging devices such as cameras, single-lens reflex electronic cameras, digital cameras, and video cameras.

多くの写真用カメラあるいはビデオカメラは自動焦点調節のための焦点検出装置を内蔵している。一眼レフカメラのように厳しいピント精度が要求される焦点検出装置においては、位相差検出方式を用いた焦点検出装置が一般的に用いられている(例えば特許文献1)。位相差検出方式は、対になった2次結像レンズ(2次結像系)により物体像(被写体像)に関する複数の光量分布を光電変換素子の画素列(ラインセンサー列)上に形成し、両光量分布の相対的位置関係から対物レンズの焦点調節状態を検出する方式である。   Many photographic cameras or video cameras have a built-in focus detection device for automatic focus adjustment. In a focus detection device that requires strict focus accuracy such as a single-lens reflex camera, a focus detection device using a phase difference detection method is generally used (for example, Patent Document 1). In the phase difference detection method, a plurality of light quantity distributions related to an object image (subject image) are formed on a pixel row (line sensor row) of a photoelectric conversion element by a paired secondary imaging lens (secondary imaging system). In this method, the focus adjustment state of the objective lens is detected from the relative positional relationship between the two light quantity distributions.

位相差検出方式の焦点検出装置において、撮影レンズの収差に起因して、焦点検出装置の読み取る焦点位置と実際の撮影レンズの焦点位置(真の焦点位置)とが異なることがある。この為、これを補完するための補正値が撮影レンズ毎に設けられている。   In the focus detection device of the phase difference detection method, the focus position read by the focus detection device may differ from the actual focus position (true focus position) of the photographic lens due to the aberration of the photographic lens. For this reason, a correction value for complementing this is provided for each photographing lens.

一般に、撮影レンズは可視域外である赤外の波長域においては収差補正がなされていない。このため、被写体(物体)の照明光として赤外光を多く含む自然光や白熱灯からの光束といった広い波長域の照明光下で撮影を行う場合と、赤外をほとんど含まない蛍光灯等の狭い波長域の照明光下で撮影を行う場合とでは、撮影レンズの収差の出方が異なり、焦点検出のための補正値を異ならせる必要がある。   In general, the photographic lens is not corrected for aberrations in the infrared wavelength region outside the visible region. For this reason, shooting is performed under illumination light in a wide wavelength range such as natural light containing a lot of infrared light as illumination light of an object (object) or a light beam from an incandescent lamp, and narrow such as a fluorescent lamp containing almost no infrared light. When shooting is performed under illumination light in the wavelength range, the way in which the aberration of the shooting lens is different is different, and the correction value for focus detection must be different.

したがった、高精度に焦点検出を行うには、被写体が照らされている光束の分光特性(光源の種類)を検知し、補正値を調整する必要がある。   Therefore, in order to perform focus detection with high accuracy, it is necessary to detect the spectral characteristic (type of light source) of the light beam illuminated by the subject and adjust the correction value.

特許文献2や3では、被写体を照明する光源の種類を検知して焦点検出を行う焦点検出装置が提案されている。   Patent Documents 2 and 3 propose focus detection apparatuses that detect the type of light source that illuminates a subject and perform focus detection.

特許文献2では、赤外部分に感度を持つセンサーと可視部分に感度を持つセンサーとの2つのセンサーを用意し、各センサーからの出力信号の強度を比較することで、光源が蛍光灯であるかそうでないかを判別している。   In Patent Document 2, two sensors, a sensor having sensitivity in the infrared part and a sensor having sensitivity in the visible part, are prepared, and the light source is a fluorescent lamp by comparing the intensity of the output signal from each sensor. Or not.

特許文献3では、蛍光灯の高周波成分(ちらつき、フリッカー)を検知することで、光源の種類を判別している。
特開2001−66496号公報 特開2001−337263号公報 特開昭62−047017号公報
In Patent Document 3, the type of light source is determined by detecting a high-frequency component (flickering, flicker) of a fluorescent lamp.
JP 2001-66496 A JP 2001-337263 A JP 62-047017 A

特許文献2で提案されている焦点検出装置では、蛍光灯の検知のために新たにユニットを用意せねばならず、複雑な装置が必要となる。その結果、カメラの重量が増大する。   In the focus detection device proposed in Patent Document 2, a new unit must be prepared for detection of a fluorescent lamp, and a complicated device is required. As a result, the weight of the camera increases.

特許文献3で検出されている焦点検出装置では、既存の測光センサーなどを利用することができるが、焦点検出精度の点で不十分である。例えば近年の蛍光灯はちらつきの少ないものが多いため、誤って光源を判定する可能性がある。また、蛍光灯からの照明光と自然光が混在して存在し、自然光が多く優勢な状況下でも、ちらつきを検知し光源を誤って判別してしまう場合があった。   The focus detection device detected in Patent Document 3 can use an existing photometric sensor or the like, but is insufficient in terms of focus detection accuracy. For example, since many fluorescent lamps in recent years have little flicker, there is a possibility that the light source is erroneously determined. In addition, illumination light from a fluorescent lamp and natural light exist together, and flicker is detected and the light source may be mistakenly determined even under a situation where natural light is dominant.

焦点検出精度を高めるには、装置が複雑にならずに被写体を照明する照明光の分光特性の違いを適切に判別し、即ち光源手段の種類を判別し、それに合った焦点検出用の補正値を用いるのが重要となってくる。   In order to increase the focus detection accuracy, the difference in the spectral characteristics of the illumination light that illuminates the subject without complicating the apparatus is appropriately determined, that is, the type of the light source means is determined, and the focus correction value corresponding thereto is determined. It is important to use

本発明は焦点検出精度を向上させることができる焦点検出装置及びそれを用いた撮像装置の提供を目的とする。   It is an object of the present invention to provide a focus detection device capable of improving focus detection accuracy and an imaging device using the focus detection device.

請求項1の発明の焦点検出装置は、撮影レンズの瞳の異なる領域を通過した光束を用いて物体像に関する複数の光量分布を形成する2次結像系と、
該2次結像系により形成した物体像に関する複数の光量分布を検出する、複数の画素より成る画素列を複数備えた光電変換素子と、
該複数の光量分布の相対的な位置関係から該撮影レンズの結像状態を求める第1,第2焦点検出系と、を有する焦点検出装置であって、
該第1,第2の焦点検出系の色収差は互いに異なっており、
該第1,第2焦点検出系で実測した第1,第2焦点検出値を第1,第2の補正値で補正した第1,第2合焦値を比較して物体を照明する光源の種類を判別し、
判別結果に基づいて、該第1,第2焦点検出値を補正する第1,第2補正値の値を変えることを特徴としている。
A focus detection apparatus according to a first aspect of the present invention includes a secondary imaging system that forms a plurality of light quantity distributions related to an object image using light beams that have passed through different areas of the pupil of the photographing lens,
A photoelectric conversion element including a plurality of pixel rows each including a plurality of pixels, which detects a plurality of light quantity distributions related to an object image formed by the secondary imaging system;
A first and second focus detection system for obtaining an imaging state of the photographing lens from a relative positional relationship of the plurality of light quantity distributions,
The chromatic aberrations of the first and second focus detection systems are different from each other,
A light source for illuminating an object by comparing the first and second focus values obtained by correcting the first and second focus detection values actually measured by the first and second focus detection systems with the first and second correction values. Determine the type
Based on the determination result, the first and second correction values for correcting the first and second focus detection values are changed.

本発明によれば、高精度の焦点検出ができる焦点検出装置が得られる。   According to the present invention, it is possible to obtain a focus detection apparatus that can perform focus detection with high accuracy.

図1は本発明の焦点検出装置を一眼レフレックスカメラに適用した実施例1の構成図である。図1において紙面内が縦方向(垂直方向)、紙面と垂直方向が横方向(水平方向)である。   FIG. 1 is a configuration diagram of Embodiment 1 in which the focus detection apparatus of the present invention is applied to a single-lens reflex camera. In FIG. 1, the inside of the paper is the vertical direction (vertical direction), and the direction perpendicular to the paper is the horizontal direction (horizontal direction).

図1において、21はカメラ本体CBに脱着可能または固定の撮影レンズ、11は撮影レンズ21の瞳、11aは瞳径である。   In FIG. 1, 21 is a photographic lens that can be attached to and detached from the camera body CB, 11 is a pupil of the photographic lens 21, and 11a is a pupil diameter.

Laは撮影レンズ21の光軸である。光軸Laにそって入射する光束は半透過部を備えるクイックリターンミラー22に達し、反射光と透過光の二つの光束に分割される。   La is the optical axis of the taking lens 21. The light beam incident along the optical axis La reaches the quick return mirror 22 having a semi-transmissive portion, and is divided into two light beams of reflected light and transmitted light.

反射側には光軸Laに沿ってフォーカシングスクリーン23、ペンタプリズム24、接眼レンズ25が配置され、これらの部材はフォーカシングスクリーン23上に形成されたファインダー像の視認のためのファインダー系を構成する。   On the reflection side, a focusing screen 23, a pentaprism 24, and an eyepiece lens 25 are arranged along the optical axis La, and these members constitute a finder system for visualizing a finder image formed on the focusing screen 23.

一方、クイックリターンミラー22の透過する側には、光軸Laに沿って、可動のサブミラー26、位相差方式の焦点検出系(焦点検出装置)FDが配置される。自動焦点検出の際には、焦点検出系FDからの出力に基づき、示されていない駆動機構によって撮影レンズ21のフォーカス部が駆動され焦点状態が調節される。   On the other hand, on the transmission side of the quick return mirror 22, a movable sub mirror 26 and a phase difference type focus detection system (focus detection device) FD are arranged along the optical axis La. At the time of automatic focus detection, based on the output from the focus detection system FD, the focus portion of the photographic lens 21 is driven by a drive mechanism (not shown) to adjust the focus state.

焦点検出系FDの詳細について説明する。2は撮影レンズ21の焦点面又はその近傍に置かれる水平方向に長い開口を有する視野マスクである。   Details of the focus detection system FD will be described. Reference numeral 2 denotes a field mask having a horizontally long opening placed at or near the focal plane of the photographing lens 21.

4は開口4a,4bを有する絞り、5は被写体像に関する2次像を形成する為の2次結像系、6は被写体像に関する2次像の光量分布(像ずれ)を検出するための複数の素子より成る光電変換素子(センサー)である。   4 is an aperture having openings 4a and 4b, 5 is a secondary imaging system for forming a secondary image relating to the subject image, and 6 is a plurality of light sources for detecting the light quantity distribution (image shift) of the secondary image relating to the subject image. This is a photoelectric conversion element (sensor) composed of the above elements.

視野マスク2から2次結像系5に至る各要素で2次結像系を構成している。   Each element from the field mask 2 to the secondary imaging system 5 constitutes a secondary imaging system.

本実施例は、撮影レンズ21の瞳11の異なる領域11b1,11b2を通過した光束を用いて、被写体像に関して、水平方向に2対以上を含む複数対の分量分布を形成する2次光学系2〜5と、複数対の光量分布の相対的な位置関係を各々検出する複数対の光電変換素子6とを有し、光電変換素子6からの信号を用いて、撮影レンズ21の焦点位置を公知の位相差検出方式を用いて検出している。   In this embodiment, a secondary optical system 2 that forms a plurality of pairs of quantity distributions including two or more pairs in the horizontal direction with respect to a subject image using light beams that have passed through different regions 11b1 and 11b2 of the pupil 11 of the photographing lens 21. -5 and a plurality of pairs of photoelectric conversion elements 6 that respectively detect the relative positional relationship of the plurality of pairs of light quantity distributions, and the focal position of the photographic lens 21 is publicly known using signals from the photoelectric conversion elements 6 This is detected using the phase difference detection method.

図2(A)は、撮影レンズ21の射出瞳11における撮影レンズ21が使用する光束範囲中のうちの焦点検出装置で使用する光束範囲の説明図である。図2(B)は図2(A)におけるそれぞれの光束に対応した焦点の位置を示した説明図である。   FIG. 2A is an explanatory diagram of a light beam range used by the focus detection device in a light beam range used by the photographing lens 21 at the exit pupil 11 of the photographing lens 21. FIG. 2B is an explanatory diagram showing the positions of the focal points corresponding to the respective light beams in FIG.

図1(A)において最大の円11aが、撮影レンズ21の射出瞳11を通過する全光束範囲であり、撮影レンズ21で使用する光束範囲である。   In FIG. 1A, the maximum circle 11 a is the total luminous flux range that passes through the exit pupil 11 of the photographing lens 21, and is the luminous flux range that is used by the photographing lens 21.

図1(B)において領域11b1,11b2を通過する光束が集光する焦点P1と、瞳全体11aを通過する光束が集光する焦点Q1とは異なっている。このときの差分Δは撮影レンズの収差が原因である。   In FIG. 1B, the focal point P1 where the light beam passing through the regions 11b1 and 11b2 is condensed differs from the focal point Q1 where the light beam passing through the entire pupil 11a is condensed. The difference Δ at this time is caused by the aberration of the taking lens.

焦点検出装置は射出瞳11a中の斜線で示された範囲11b1,11b2を利用する。撮影レンズには一般に球面収差が存在する。このため、光軸からの高さの低い範囲の光束を使用する焦点検出装置では、全光束を使用した撮影レンズの焦点位置と異なる位置を焦点位置(合焦検出値)であると判断してしまう。この相違を解消するために、各撮影レンズやそれを用いるカメラは合焦誤差を補正するための補正値を記憶しており、実測された合焦検出値を補正値で補正した合焦値を用いている。   The focus detection apparatus uses ranges 11b1 and 11b2 indicated by oblique lines in the exit pupil 11a. A photographic lens generally has spherical aberration. For this reason, in a focus detection apparatus that uses a light beam having a low height from the optical axis, a position different from the focus position of the photographing lens using all light beams is determined as the focus position (focus detection value). End up. In order to eliminate this difference, each photographing lens and the camera using the same store a correction value for correcting the focus error, and the focus value obtained by correcting the actually measured focus detection value with the correction value is stored. Used.

また、焦点検出の動作において、合焦精度を向上させるために被写体が暗い場合に、カメラ側から光を被写体に投光することがある。この時に使用する光は、撮影構図への影響の回避から、可視域外の赤外光(波長700〜800nm)、例えば赤外発光ダイオードからの赤外光を使っている。したがって、焦点検出装置の光路中に使用する赤外カットのフィルターは、撮影センサーの光入射側に使用している赤外カットフィルターよりもより長波長側の赤外光を透過させている。   In the focus detection operation, when the subject is dark in order to improve the focusing accuracy, light may be projected onto the subject from the camera side. The light used at this time uses infrared light outside the visible range (wavelength 700 to 800 nm), for example, infrared light from an infrared light emitting diode, in order to avoid an influence on the photographing composition. Therefore, the infrared cut filter used in the optical path of the focus detection device transmits infrared light having a longer wavelength than the infrared cut filter used on the light incident side of the imaging sensor.

撮影レンズの諸収差は、可視域(波長400〜700nm)で補正されるように設計が行われている。このため、赤外域では収差が多く残存している。図3には、ある撮影レンズの球面収差の概念図である。SA1は可視域の球面収差、SA2は赤外域の球面収差である。図3から明らかのように可視域の球面収差は座標の中心(ガウス像面)近辺に存在しているのに対し、赤外域の球面収差では中心から大きく外れているのが分かる。先に述べたように、撮影レンズの焦点位置と焦点検出装置で検出される焦点位置の相違は収差が主たる原因となって生ずる。このため、赤外域で検出された焦点位置は、可視域で検出された焦点位置と大きく異なってくる。   Various aberrations of the photographing lens are designed so as to be corrected in the visible region (wavelength 400 to 700 nm). For this reason, many aberrations remain in the infrared region. FIG. 3 is a conceptual diagram of spherical aberration of a photographic lens. SA1 is a spherical aberration in the visible region, and SA2 is a spherical aberration in the infrared region. As can be seen from FIG. 3, the spherical aberration in the visible region exists near the center of the coordinates (Gauss image plane), whereas the spherical aberration in the infrared region deviates greatly from the center. As described above, the difference between the focal position of the photographing lens and the focal position detected by the focus detection apparatus is mainly caused by aberration. For this reason, the focal position detected in the infrared region is greatly different from the focal position detected in the visible region.

図4は、撮影で使用される代表的な光源と太陽光の波長依存強度を表したグラフである。横軸が波長、縦軸が光発光強度である。   FIG. 4 is a graph showing the wavelength-dependent intensity of a typical light source and sunlight used for photographing. The horizontal axis represents wavelength, and the vertical axis represents light emission intensity.

それぞれのラインは、太陽や白熱灯、蛍光灯のものである。焦点位置の検出誤差への影響という点では、上に述べた理由から光源が赤外光を多く含む場合とほとんど含まない場合とに区別されるべきである。ここでは、自然光や白熱灯からの光は赤外光を多く含む光源、蛍光灯からの光は赤外光をほとんど含まない光源である。実施例1では撮影に際してこの2種類の光源を判別し、焦点位置を求めるときには、それぞれの区分に対応した補正値を利用することで、光源の差異による焦点位置の違い(焦点検出誤差)を緩和している。   Each line is for the sun, an incandescent lamp or a fluorescent lamp. In view of the influence on the detection error of the focal position, a distinction should be made between the case where the light source contains a lot of infrared light and the case where it hardly contains the infrared light for the reasons described above. Here, natural light or light from an incandescent lamp is a light source that contains a lot of infrared light, and light from a fluorescent lamp is a light source that contains almost no infrared light. In the first embodiment, when the two types of light sources are discriminated at the time of photographing and the focal position is obtained, the difference in the focal position (focus detection error) due to the difference of the light sources is reduced by using a correction value corresponding to each section. is doing.

図5は、位相差方式を用いた焦点検出装置の一部分の概念図である。   FIG. 5 is a conceptual diagram of a part of a focus detection apparatus using a phase difference method.

撮像面と光学的に等価な位置にある1次結像面3と、1次結像面3を通過した光束を2つの領域に分割する2つの開口4a,4bを有する絞り4と、絞り4の開口4a,4bを通過した光に基づく2次物体像6a,6bをラインセンサー6上に結像する1対のレンズ5a,5bより成る2次結像系5を有している。   A primary imaging plane 3 that is optically equivalent to the imaging plane, a diaphragm 4 having two openings 4a and 4b that divide the light beam that has passed through the primary imaging plane 3 into two regions, and a diaphragm 4 The secondary image forming system 5 includes a pair of lenses 5a and 5b for forming an image of the secondary object images 6a and 6b based on the light passing through the apertures 4a and 4b on the line sensor 6.

焦点位置は、絞り4のそれぞれの開口4a,4bを通りラインセンサー6に投影される2つの2次物体像6a,6bの間隔(相対的なずれ量)で判断される。例えば、2つの2次物体像6a,6bの間隔が予め設定した基準値に比べ広い時には後ピン(本来焦点を合わせたい被写体よりも後方にピントが合っている状態)、間隔が狭い時には前ピン(本来焦点を合わせたい被写体よりも前方にピントが合っている状態)である。   The focal position is determined by the interval (relative shift amount) between the two secondary object images 6a and 6b projected through the openings 4a and 4b of the stop 4 and projected onto the line sensor 6. For example, when the distance between the two secondary object images 6a and 6b is wider than a preset reference value, the rear pin is in focus (in a state where the subject is originally focused on), and when the distance is narrow, the front pin is (A state in which the subject is originally focused on and in focus).

図6は、焦点検出の際に、撮影レンズの色収差を調整するための2次結像系5の一方のレンズ5aの説明図である。図6のレンズ5aは、前面(光入射側)にプリズム5a1、後面にレンズ5a2を配置して構成されている。プリズム5a1の角度とレンズ5a2の紙面上下方向の偏心によりプリズム作用を起し、波長に依存してラインセンサー6上での結像位置を変化させている。   FIG. 6 is an explanatory diagram of one lens 5a of the secondary imaging system 5 for adjusting the chromatic aberration of the photographing lens during focus detection. The lens 5a of FIG. 6 is configured by arranging a prism 5a1 on the front surface (light incident side) and a lens 5a2 on the rear surface. The prism action is caused by the angle of the prism 5a1 and the eccentricity of the lens 5a2 in the vertical direction on the paper surface, and the imaging position on the line sensor 6 is changed depending on the wavelength.

ここでは、波長の長い光線9をより内側に、波長の短い光線8を外側に屈折させている。このようなプリズム作用によって色収差を発生させた2次結像系5に長波長の光が入射すると、色収差がほとんど無い2次結像系に入射した場合に比べて2つの2次物体像6a,6bの間隔は狭くなり、より前ピンの傾向を示す。一方、短波長の光が入射したときには、長波長の光が入射したときと逆で2つの2次物体像6a,6bの間隔は広くなり、より後ピンの傾向を示す。   Here, the light beam 9 having a long wavelength is refracted inward and the light beam 8 having a short wavelength is refracted outward. When light having a long wavelength is incident on the secondary imaging system 5 in which chromatic aberration is generated by such a prism action, two secondary object images 6a, 6a, The interval of 6b becomes narrow and shows the tendency of a front pin more. On the other hand, when short-wavelength light is incident, the interval between the two secondary object images 6a and 6b is widened as opposed to when long-wavelength light is incident, and a tendency toward a rear pin is exhibited.

図7は、実施例1における焦点検出装置の一部分の概念図である。図6において、2つの焦点検出系71,72の色収差はそれぞれ異なっており、波長の違いによって検出される焦点位置が異なる。   FIG. 7 is a conceptual diagram of a part of the focus detection apparatus according to the first embodiment. In FIG. 6, the chromatic aberrations of the two focus detection systems 71 and 72 are different from each other, and the detected focal positions are different depending on the wavelength.

また、2つの焦点検出系71,72はほぼ同一の距離(物体の同一の領域)を測定する必要があるため、ラインセンサー61,62に取り込む光線が1次結像面3上のほぼ同じ箇所を通過するように各部材を配置している。   Further, since the two focus detection systems 71 and 72 need to measure substantially the same distance (the same region of the object), the light rays taken into the line sensors 61 and 62 are almost the same place on the primary imaging plane 3. Each member is arranged to pass through.

焦点検出系71の2次結像系51のプリズム作用は、焦点検出系72の2次結像系52のプリズム作用に比べて大きい。   The prism action of the secondary imaging system 51 of the focus detection system 71 is larger than the prism action of the secondary imaging system 52 of the focus detection system 72.

本実施例では2つの焦点検出系71,72のそれぞれの色収差を異ならせている。   In this embodiment, the chromatic aberrations of the two focus detection systems 71 and 72 are made different.

本実施例の2つの焦点検出系71,72は、プリズム作用の大きさが違うためラインセンサー61,62に入射する光の中に長波長が多く含まれるかあるいはほとんど含まれないかによって、二つの焦点検出系71,72から導かれるピントずれ量(合焦信号)が変化する。これにより、光源の種類の検知が可能となる。   The two focus detection systems 71 and 72 according to the present embodiment have two different prisms depending on whether the light incident on the line sensors 61 and 62 includes many or almost no long wavelengths. The amount of focus deviation (focus signal) derived from the two focus detection systems 71 and 72 changes. As a result, the type of light source can be detected.

以下に、本実施例における焦点検出の流れを図8のフローに基づいて述べる。   Hereinafter, the flow of focus detection in this embodiment will be described based on the flow of FIG.

焦点検出を行った時、一方の焦点検出系71からの出力されたピントのずれ量(第1焦点検出値)をAF1、焦点検出系71と異なる色収差のあるもう一方の焦点検出72からの出力されたピントのずれ量(第2焦点検出値)をAF2とする。   When focus detection is performed, the focus shift amount (first focus detection value) output from one focus detection system 71 is output from AF1 and the other focus detection 72 having chromatic aberration different from that of the focus detection system 71. The amount of focus shift (second focus detection value) is AF2.

特定の光源下(基準光源)で、この出力値と実際の合焦値(真の焦点位置)との差分を解消するための補正値をそれぞれ第1,第2補正値C1、C2として、あらかじめ基準光源下で調整を行い、撮影レンズ内又はカメラ本体内の記憶手段に記憶している。   Under a specific light source (reference light source), correction values for eliminating the difference between the output value and the actual focus value (true focus position) are first and second correction values C1 and C2, respectively. Adjustments are made under a reference light source and stored in storage means in the taking lens or in the camera body.

今回は、例えば基準光源として赤外域を多く含む太陽光を光源として利用する。また、第1焦点検出値AF1を出す焦点検出系71に比べ、第2焦点検出値AF2を出す焦点検出系72は短波長に比べ長波長をより光軸に近く(より内側に)曲げるプリズム作用を持っている(赤外域に向ける球面収差量が大きい)。   This time, for example, sunlight containing a large amount of infrared light is used as a light source as a reference light source. Compared with the focus detection system 71 that outputs the first focus detection value AF1, the focus detection system 72 that outputs the second focus detection value AF2 has a prism action that bends the long wavelength closer to the optical axis (inward) than the short wavelength. (The amount of spherical aberration toward the infrared region is large).

次に実際に焦点検出を行う時、光源が基準光源か或いはそうでないか(照明光の分光特性が基準分布をしているかそうでないか)を判断する流れを述べる。撮影するときの光源が、赤外光を多く含む時は合焦検出値AF1と補正値C1を加えた値(第1合焦値)と、合焦検出値AF2と補正値C2を加えた値(第2合焦値)は、赤外光を多く含む基準光源で調整されているため、ほぼ同程度の値となる。   Next, a flow for determining whether or not the light source is the reference light source when actually performing focus detection (whether or not the spectral characteristic of the illumination light has the reference distribution) will be described. When the light source for photographing includes a lot of infrared light, a value obtained by adding the focus detection value AF1 and the correction value C1 (first focus value), and a value obtained by adding the focus detection value AF2 and the correction value C2. Since the (second focus value) is adjusted with a reference light source that contains a large amount of infrared light, the second focus value is approximately the same.

一方、撮影するときの光源が赤外光をほとんど含まない光源、例えば蛍光灯であれば、第1焦点検出値AF1と第2焦点検出値AF2のプリズム作用の違いから、第1焦点検出値AF1と補正値C1を加えた値(第1合焦値)は、第2焦点検出値AF2と第2補正値C2を加えた値(第2合焦値)よりも後ピン(大きい)であることを示す。   On the other hand, if the light source at the time of photographing is a light source that hardly contains infrared light, for example, a fluorescent lamp, the first focus detection value AF1 is derived from the prism action difference between the first focus detection value AF1 and the second focus detection value AF2. And the value obtained by adding the correction value C1 (first focus value) is a rear pin (larger) than the value obtained by adding the second focus detection value AF2 and the second correction value C2 (second focus value). Indicates.

第1合焦値と第2合焦値の差Δに閾値(δ)以上か否かの判断から、光源が蛍光灯であるか、或いは基準光源に近い光源かのどちらかが判別ができる。   Whether the light source is a fluorescent lamp or a light source close to the reference light source can be determined from determining whether the difference Δ between the first focus value and the second focus value is greater than or equal to a threshold value (δ).

この判断に従い蛍光灯下の撮影である場合は、補正値C1、C2と異なる値の補正値C’1、C’2を利用し焦点検出を行う。   When photographing under a fluorescent lamp according to this determination, focus detection is performed using correction values C′1 and C′2 that are different from the correction values C1 and C2.

これらの一連の動作は、カメラ本体内の演算手段によって行っている。そして2つの焦点検出系から得られる第1,第2合焦値の少なくとも一方を用いて合焦レンズを駆動させて合焦操作を行っている。   A series of these operations is performed by a calculation means in the camera body. Then, the focusing operation is performed by driving the focusing lens using at least one of the first and second focusing values obtained from the two focus detection systems.

本実施例において、閾値(δ)を1つに限らず何種類か設けても良く、これによれば多数の光源の検知も可能となり、高い精度で焦点検出ができる。   In this embodiment, the number of threshold values (δ) is not limited to one, and several types of threshold values (δ) may be provided. According to this, a large number of light sources can be detected, and focus detection can be performed with high accuracy.

以上のように本実施例では、位相差検出方式により焦点を検出する第一焦点検出系と、第一焦点検出系と異なる色収差を加えた位相差検出方式により焦点を検出する第二焦点検出系を備え、第一と第二焦点検出系からの出力を用いて、被写体を照射する照明手段が赤外域を多く含む光源であるか否かを判別し、その判別に従って補正した合焦値を用いることによって高精度の合焦操作を行っている。   As described above, in this embodiment, the first focus detection system that detects the focus by the phase difference detection method and the second focus detection system that detects the focus by the phase difference detection method to which chromatic aberration different from the first focus detection system is added. And using the outputs from the first and second focus detection systems, it is determined whether or not the illumination means for illuminating the subject is a light source including a large amount of infrared region, and the focus value corrected according to the determination is used. Thus, a highly accurate focusing operation is performed.

以上のように、本実施例によれば、照明手段(光源)の違いに従い焦点検出系からの出力が変化するので、その変化を判定することで自然光か蛍光灯からの光かを検出することが可能となる。照明手段が判別されたあとは、それぞれに依存する補正値を用いて合焦値(焦点位置)を求めることで、より精度の高い焦点検出(測距)が可能となる。   As described above, according to the present embodiment, since the output from the focus detection system changes according to the difference in illumination means (light source), it is possible to detect natural light or light from a fluorescent lamp by determining the change. Is possible. After the illuminating means is determined, the focus value (focus position) is obtained using correction values depending on the illumination means, thereby enabling more accurate focus detection (ranging).

本発明の焦点検出装置を有する撮像装置の説明図Explanatory drawing of the imaging device which has the focus detection apparatus of this invention (A)ある撮影レンズの、射出瞳面における撮影に使用する光束と焦点検出系で使用する光束(斜線)の違いを表した概念図。(B)撮影レンズと焦点検出系の光束のおける焦点位置の違いを表した概念図。(A) The conceptual diagram showing the difference of the light beam used for imaging | photography on an exit pupil surface, and the light beam (diagonal line) used by a focus detection system of a certain imaging lens. (B) The conceptual diagram showing the difference in the focus position in the light beam of a photographic lens and a focus detection system. 撮影レンズの代表的な球面収差図。The typical spherical aberration figure of a taking lens. 様々な光源から放射される光束の強度の波長依存性。Wavelength dependence of the intensity of luminous flux emitted from various light sources. 位相差検出方式を用いた焦点検出装置の概念図。The conceptual diagram of the focus detection apparatus using a phase difference detection system. 波長の違いに依存した結像位置の違いを表した概念図。The conceptual diagram showing the difference in the imaging position depending on the difference in wavelength. 本発明において光源検知を行う焦点検出装置の概念図。The conceptual diagram of the focus detection apparatus which performs light source detection in this invention. 光源検知、焦点検出を行うための流れを表した図。The figure showing the flow for performing light source detection and focus detection.

符号の説明Explanation of symbols

SA1 可視域の収差
SA2 赤外の収差
2 視野マスク
3 1次結像面
4 絞り
5 2次結像系
6 センサー
71,72 2次結像系
8 長波長光線の通過経路
9 短波長光線の通過経路
21 撮影レンズ
SA1 Visible region aberration SA2 Infrared aberration 2 Field mask 3 Primary imaging plane 4 Aperture 5 Secondary imaging system 6 Sensors 71 and 72 Secondary imaging system 8 Long-wavelength light path 9 Short-wavelength light path Path 21 Photo lens

Claims (5)

撮影レンズの瞳の異なる領域を通過した光束を用いて物体像に関する複数の光量分布を形成する2次結像系と、
該2次結像系により形成した物体像に関する複数の光量分布を検出する、複数の画素より成る画素列を複数備えた光電変換素子と、
該複数の光量分布の相対的な位置関係から該撮影レンズの結像状態を求める第1,第2焦点検出系と、を有する焦点検出装置であって、
該第1,第2の焦点検出系の色収差は互いに異なっており、
該第1,第2焦点検出系で実測した第1,第2焦点検出値を第1,第2の補正値で補正した第1,第2合焦値を比較して物体を照明する光源の種類を判別し、
判別結果に基づいて、該第1,第2焦点検出値を補正する第1,第2補正値の値を変えることを特徴とする焦点検出装置。
A secondary imaging system that forms a plurality of light quantity distributions related to the object image using light beams that have passed through different areas of the pupil of the taking lens;
A photoelectric conversion element including a plurality of pixel rows each including a plurality of pixels, which detects a plurality of light quantity distributions related to an object image formed by the secondary imaging system;
A first and second focus detection system for obtaining an imaging state of the photographing lens from a relative positional relationship of the plurality of light quantity distributions,
The chromatic aberrations of the first and second focus detection systems are different from each other,
A light source for illuminating an object by comparing the first and second focus values obtained by correcting the first and second focus detection values actually measured by the first and second focus detection systems with the first and second correction values. Determine the type
A focus detection apparatus that changes values of first and second correction values for correcting the first and second focus detection values based on a determination result.
前記第1,第2焦点検出系で焦点検出を行う物体の領域は同一であり、
前記第1,第2焦点検出系は、前記対物レンズの瞳の同一領域を通過する光束を用いていること
を特徴とする請求項1の焦点検出装置。
The region of the object that performs focus detection in the first and second focus detection systems is the same,
The focus detection apparatus according to claim 1, wherein the first and second focus detection systems use light beams that pass through the same region of the pupil of the objective lens.
前記第1,第2焦点検出系は、互いにプリズム頂角の異なるプリズムを光路中に設けていることを特徴とする請求項1又は2の焦点検出装置。   3. The focus detection apparatus according to claim 1, wherein the first and second focus detection systems are provided with prisms having different prism apex angles in the optical path. 請求項1乃至3の何れか1項に記載の焦点検出装置と、該焦点検出装置で求めた合焦信号に基づいて対物レンズの合焦レンズを駆動させることを特徴とする撮像装置。   An imaging apparatus comprising: the focus detection apparatus according to claim 1; and an in-focus lens of an objective lens that is driven based on a focus signal obtained by the focus detection apparatus. 撮影レンズの瞳の異なる領域を通過した光束を用いて物体像に関する複数の光量分布を形成する2次結像系と、
該2次結像系により形成した物体像に関する複数の光量分布を検出する、複数の画素より成る画素列を複数備えた光電変換素子と、
該複数の光量分布の相対的な位置関係から該撮影レンズの結像状態を物体の同一領域において求める第1,第2焦点検出系と、を有し、
該第1,第2の焦点検出系の色収差は互いに異なっており、
該第1,第2焦点検出系で各々実測した第1,第2焦点検出値を補正する第1,第2補正値を有しており、
該第1,第2焦点検出値を該第1,第2補正値で補正した第1,第2合焦値を比較して物体が照明された照明手段の種類を判別し、
判別結果に基づいて、該第1,第2焦点検出値を補正する第1,第2補正値の値を変える演算手段を備えること
を有することを特徴とする焦点検出システム。
A secondary imaging system that forms a plurality of light quantity distributions related to the object image using light beams that have passed through different areas of the pupil of the taking lens;
A photoelectric conversion element including a plurality of pixel rows each including a plurality of pixels, which detects a plurality of light quantity distributions related to an object image formed by the secondary imaging system;
A first focus detection system and a second focus detection system for determining an imaging state of the photographing lens in the same region of the object from a relative positional relationship of the plurality of light quantity distributions;
The chromatic aberrations of the first and second focus detection systems are different from each other,
Having first and second correction values for correcting the first and second focus detection values actually measured in the first and second focus detection systems,
Comparing the first and second focus values obtained by correcting the first and second focus detection values with the first and second correction values to determine the type of illumination means on which the object is illuminated;
A focus detection system comprising: an arithmetic unit that changes values of the first and second correction values for correcting the first and second focus detection values based on a determination result.
JP2005214514A 2005-07-25 2005-07-25 Focus detection device and imaging apparatus using the same Pending JP2007033653A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005214514A JP2007033653A (en) 2005-07-25 2005-07-25 Focus detection device and imaging apparatus using the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005214514A JP2007033653A (en) 2005-07-25 2005-07-25 Focus detection device and imaging apparatus using the same

Publications (1)

Publication Number Publication Date
JP2007033653A true JP2007033653A (en) 2007-02-08

Family

ID=37793026

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005214514A Pending JP2007033653A (en) 2005-07-25 2005-07-25 Focus detection device and imaging apparatus using the same

Country Status (1)

Country Link
JP (1) JP2007033653A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1975695A3 (en) * 2007-03-28 2008-12-10 Nikon Corporation Focus detection device, focusing state detection method and imaging apparatus
US10025162B2 (en) 2014-05-01 2018-07-17 Canon Kabushiki Kaisha Focus adjustment device for correcting autofocus of focus lens using captured image signal to be recorded, method for controlling the same, and image capture apparatus
JP2019040080A (en) * 2017-08-25 2019-03-14 キヤノン株式会社 Imaging apparatus and control method of the same
EP3633879A4 (en) * 2017-06-01 2020-06-24 Panasonic Intellectual Property Corporation of America Reception device and reception method

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1975695A3 (en) * 2007-03-28 2008-12-10 Nikon Corporation Focus detection device, focusing state detection method and imaging apparatus
US7873267B2 (en) 2007-03-28 2011-01-18 Nikon Corporation Focus detection device, focusing state detection method and imaging apparatus
US10025162B2 (en) 2014-05-01 2018-07-17 Canon Kabushiki Kaisha Focus adjustment device for correcting autofocus of focus lens using captured image signal to be recorded, method for controlling the same, and image capture apparatus
US11099459B2 (en) 2014-05-01 2021-08-24 Canon Kabushiki Kaisha Focus adjustment device and method capable of executing automatic focus detection, and imaging optical system storing information on aberrations thereof
US11822211B2 (en) 2014-05-01 2023-11-21 Canon Kabushiki Kaisha Imaging optical system storing information on its aberration, imaging apparatus, and control method thereof
EP3633879A4 (en) * 2017-06-01 2020-06-24 Panasonic Intellectual Property Corporation of America Reception device and reception method
US11296788B2 (en) 2017-06-01 2022-04-05 Panasonic Intellectual Property Corporation Of America Reception device and reception method
JP2019040080A (en) * 2017-08-25 2019-03-14 キヤノン株式会社 Imaging apparatus and control method of the same

Similar Documents

Publication Publication Date Title
JP5168798B2 (en) Focus adjustment device and imaging device
JP4972960B2 (en) Focus adjustment device and imaging device
JP5168797B2 (en) Imaging device
US7940323B2 (en) Image-pickup apparatus and control method thereof
JP2008275712A (en) Imaging apparatus
WO2016157291A1 (en) Measuring head and eccentricity measuring device provided with same
JP5850627B2 (en) Imaging device
JP2008242333A (en) Imaging apparatus and method of controlling the same
JP2007033653A (en) Focus detection device and imaging apparatus using the same
JP4208536B2 (en) Focus detection device, imaging device having the same, and photographing lens
JP5794665B2 (en) Imaging device
JP2012203278A (en) Imaging apparatus, lens device and camera system
JP4950634B2 (en) Imaging apparatus and imaging system
JP2006317595A (en) Optical apparatus and its control method
JP2006135513A (en) Imaging apparatus
JP2017219791A (en) Control device, imaging device, control method, program, and storage medium
JP2009128843A (en) Focus detecting device and image pickup apparatus having the same
JP5043402B2 (en) Photometric device and camera
JP4933274B2 (en) FOCUS ADJUSTMENT DEVICE, ITS CONTROL METHOD, AND IMAGING DEVICE
JPH05264892A (en) Automatic focusing device
JP2019139031A (en) Imaging apparatus and method for controlling the same
JP2006146081A (en) Ranging device and imaging apparatus
JP2009003423A (en) Optical equipment and method for manufacturing optical equipment
JP4514202B2 (en) Interchangeable lens, camera body and camera system
JPS62183416A (en) Focus detecting device