JPH0145883B2 - - Google Patents
Info
- Publication number
- JPH0145883B2 JPH0145883B2 JP56159213A JP15921381A JPH0145883B2 JP H0145883 B2 JPH0145883 B2 JP H0145883B2 JP 56159213 A JP56159213 A JP 56159213A JP 15921381 A JP15921381 A JP 15921381A JP H0145883 B2 JPH0145883 B2 JP H0145883B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- light receiving
- infrared
- lens
- receiving device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000003384 imaging method Methods 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 15
- 230000003287 optical effect Effects 0.000 claims description 14
- 239000000758 substrate Substances 0.000 claims description 7
- 230000004907 flux Effects 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 230000003595 spectral effect Effects 0.000 description 21
- 238000001514 detection method Methods 0.000 description 18
- 238000011156 evaluation Methods 0.000 description 15
- 230000035945 sensitivity Effects 0.000 description 13
- 238000003491 array Methods 0.000 description 11
- 230000004075 alteration Effects 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 229910052710 silicon Inorganic materials 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 4
- 238000002834 transmittance Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/28—Systems for automatic generation of focusing signals
- G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
- G02B7/38—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals measured at different points on the optical axis, e.g. focussing on two or more planes and comparing image data
Description
【発明の詳細な説明】
本発明は、物体の像を形成する結像光学系から
の光束の少なくとも一部を受光装置で受光し、こ
の受光装置で前記光束の強度分布を光電信号に変
換し、この光電信号に基づいて物体像の結像状態
を判別して結像光学系の焦点合わせを行なう自動
焦点調節方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a light receiving device receives at least a portion of a light beam from an imaging optical system that forms an image of an object, and the light receiving device converts the intensity distribution of the light beam into a photoelectric signal. This invention relates to an automatic focusing method that determines the imaging state of an object image based on this photoelectric signal and focuses an imaging optical system.
普通の写真撮影用レンズでは通常可視光につい
てのみ色収差を補正してあり、赤外光に対しては
収差補正がされていない。したがつて、このよう
なレンズで赤外線写真を撮影する場合には、最初
に可視光でピントを合わせた後、レンズを操り出
して赤外マークに目印を合わせ直して撮影するの
できわめて面倒である。一方、このようなレンズ
を持つたカメラに自動焦点を適用する場合、レン
ズを透過した光束を受光して合焦状態の検出を行
なう、いわゆるTTL方式を採用するものがある。
例えば第１図に示すように物体１の像を撮影レン
ズ２により撮影する場合、レンズ２を透過した光
束をハーフミラー３により二分し、それぞれ予定
結像面Ｆの前後に配置した受光素子列４および５
で受光している。これら受光素子列４および５は
予定結像面から等しい光路差だけ隔たるように配
置されており、したがつてレンズ２の移動に伴う
受光素子列上の像のぼけ方は第２図に示すように
なり、合焦時には同程度にぼけた像が受光素子列
４および５上に結像されるが、いわゆる前ピンお
よび後ピンの状態ではそれぞれ受光素子列４およ
び５によりピントの合つた像が形成されることに
なる。したがつてこれらの状態では第１および第
２の受光素子列４および５の各受光素子の出力信
号は第３図においてそれぞれ実線および破線で示
すようになる。したがつてこれら受光素子の光電
出力信号を所定の評価関数にしたがつて演算する
と、第４図に示すようなものとなる。すなわち、
第４図の実線は第１の受光素子列４の出力から求
めた評価関数値を、破線は第２の受光素子列５の
出力から求めた評価関数値をそれぞれ示す。また
第４図において、δは両受光素子列の間隔を示し
ている。評価関数としては隣接する受光素子の出
力の差の絶対値の内の最大のもの｜xo−xo+1｜na
ｘや、絶対値の和Σ｜xo＋xo+1｜などがあるが、
いずれにしても受光素子上の形成される像の鮮鋭
度が最も高いとき、すなわちコントラストが最大
となるとき、評価関数値は最大値をとる。したが
つて各受光素子列の出力から演算される評価値の
ピークからδ／２だけ離れた点を合焦点位置とすれ
ば、この位置では両評価値の差は零となるので、
両評価値の差の正負、零を判定することにより後
ピン状態、前ピン状態、合焦状態を判定すること
ができる。 In ordinary photography lenses, chromatic aberration is usually corrected only for visible light, but not for infrared light. Therefore, when taking infrared photographs with such a lens, it is extremely troublesome to first focus using visible light, then move the lens out, re-align the mark with the infrared mark, and then take the photograph. . On the other hand, when applying autofocus to a camera with such a lens, there are some that employ the so-called TTL method, which detects the in-focus state by receiving the light flux that has passed through the lens.
For example, when photographing an image of an object 1 using a photographing lens 2 as shown in FIG. and 5
It is receiving light. These light-receiving element rows 4 and 5 are arranged so as to be separated by an equal optical path difference from the intended image-forming plane. Therefore, the blurring of the image on the light-receiving element row as the lens 2 moves is shown in FIG. When in focus, equally blurred images are formed on the photodetector arrays 4 and 5, but in the so-called front-focus and rear-focus states, images are focused by the photodetector arrays 4 and 5, respectively. will be formed. Therefore, in these conditions, the output signals of the respective light receiving elements of the first and second light receiving element rows 4 and 5 become as shown by solid lines and broken lines, respectively, in FIG. Therefore, when the photoelectric output signals of these light receiving elements are calculated according to a predetermined evaluation function, the result is as shown in FIG. That is,
The solid line in FIG. 4 indicates the evaluation function value obtained from the output of the first light receiving element array 4, and the broken line indicates the evaluation function value obtained from the output of the second light receiving element array 5. Further, in FIG. 4, δ indicates the interval between both light-receiving element rows. The evaluation function is the maximum absolute value of the difference in output between adjacent light receiving elements | x o −x o+1 | na
x , the sum of absolute values Σ|x o +x o+1 |, etc.
In any case, when the sharpness of the image formed on the light receiving element is highest, that is, when the contrast is maximum, the evaluation function value takes the maximum value. Therefore, if a point δ/2 apart from the peak of the evaluation value calculated from the output of each light-receiving element array is set as the in-focus position, the difference between the two evaluation values will be zero at this position.
By determining whether the difference between the two evaluation values is positive or negative, or whether it is zero, it is possible to determine the rear focus state, front focus state, and in-focus state.
第５図は上述した合焦検出方法に基づく自動焦
点調節装置全体の構成を示すものであり、物体１
の像を形成するレンズ２からの光束を、上述した
ように光路差を与えた第１および第２の受光素子
列を有する受光装置７で受光し、その光電変換出
力を信号処理回路１０でＡ―Ｄ変換し、演算回路
１１で２つの評価値を計算し、その差を制御回路
１２へ送る。制御回路１２はこの差の正、負、零
を判断し、それに応じてレンズ駆動装置８を制御
し、レンズ２を光軸方向に移動させる。このレン
ズ２の移動量を移動量検出器９で検出し、これを
制御回路１２へ送る。制御回路１２では所定の距
離の移動が終了したことを検出したらレンズ駆動
装置８によるレンズの駆動を停止し、再び受光装
置７による像情報をとり込み、評価値の演算を行
ない、合焦位置へのレンズの移動方向を決定し、
再びレンズ駆動装置８によりレンズ２を所定量移
動する。このような動作を、両評価値の差が零と
なるまで繰返し、最終状態ではレンズ２は予定の
結像面にピントの合つた像を形成する合焦点位置
となる。 FIG. 5 shows the overall configuration of an automatic focus adjustment device based on the focus detection method described above.
The light beam from the lens 2 that forms an image of -D conversion, the arithmetic circuit 11 calculates two evaluation values, and sends the difference to the control circuit 12. The control circuit 12 determines whether this difference is positive, negative, or zero, controls the lens driving device 8 accordingly, and moves the lens 2 in the optical axis direction. The amount of movement of this lens 2 is detected by a movement amount detector 9 and sent to a control circuit 12. When the control circuit 12 detects that the movement of the predetermined distance has been completed, it stops driving the lens by the lens driving device 8, takes in the image information from the light receiving device 7 again, calculates the evaluation value, and returns to the in-focus position. determine the direction of movement of the lens,
The lens 2 is moved by a predetermined amount again by the lens driving device 8. This operation is repeated until the difference between the two evaluation values becomes zero, and in the final state, the lens 2 is at the focal point position where a focused image is formed on the intended imaging plane.
上述した自動焦点調節装置において使用する受
光素子は、例えばシリコンホトダイオードであ
り、これは第６図に示すような分光感度特性を持
つており、760ｍμから1.3μの近赤外域において
ピークを有している。一方、物体を照射する光は
一般に種々の波長の光を含んでおり、例えば太陽
光線の分光強度は第７図に示すように近赤外域に
おいても大きな強度があり、デイライトカラー用
のフラツトランプの分光強度特性も第８図に示す
ように近赤外域に大きな相対エネルギーを含んで
おり、螢光灯でも第９図に示すように赤外域にお
ける相対エネルギーは小さいながら存在してい
る。このように撮影光の中には近赤外域が含まれ
ている。一方、撮影レンズ２は通常Ｄ線（589n
ｍ）を中心に可視光に対してのみ色収差が補正さ
れており、赤外線に対しては補正されていないの
で、この補正されていない赤外線に対して大きな
感度を有する受光装置をそのまま用いて可視光の
撮影をするときには合焦点位置がレンズより遠去
かる位置になり、ピントの合つた可視光像が得ら
れないことになる。したがつて、受光装置の前方
に赤外線カツトフイルタを挿入し、可視光のみで
合焦検出を行なうようにしている。しかし、この
ような赤外線カツトフイルタを挿入すると、750
〜800nｍ付近に大きな感度を有する赤外写真用
フイルムを用いて赤外線撮影をする場合には合焦
検出が正しく行なえなくなる欠点がある。可視光
による合焦点位置と赤外線による合焦点位置との
ずれはレンズ設計の段階で知ることができるの
で、可視光により合焦検出した後、このずれに対
応した量だけレンズを移動させることによつて赤
外線に対して合焦させることもできるが、入射光
束中に可視光と赤外光とがどの位の割合で含まれ
ているのがわからなければレンズを正確に合焦点
位置に調節するように補正することはできない。 The light-receiving element used in the above-mentioned automatic focusing device is, for example, a silicon photodiode, which has spectral sensitivity characteristics as shown in Figure 6, with a peak in the near-infrared region from 760 mμ to 1.3μ. There is. On the other hand, the light that irradiates an object generally contains light of various wavelengths. For example, the spectral intensity of sunlight has a large intensity even in the near-infrared region, as shown in Figure 7. The spectral intensity characteristics of the light also include large relative energy in the near-infrared region, as shown in FIG. 8, and even in fluorescent lamps, as shown in FIG. 9, the relative energy in the infrared region is small, but still exists. In this way, the photographing light includes near-infrared light. On the other hand, the photographing lens 2 is normally D-line (589n
Since chromatic aberration is corrected only for visible light (centered on m), but not for infrared light, this uncorrected light receiving device, which has high sensitivity to infrared light, can be used as is to detect visible light. When photographing, the focal point position is farther away than the lens, making it impossible to obtain a focused visible light image. Therefore, an infrared cut filter is inserted in front of the light receiving device so that focus detection is performed using only visible light. However, if you insert an infrared cut filter like this, 750
When performing infrared photography using an infrared photographic film having a high sensitivity in the vicinity of ~800 nm, there is a drawback that focus detection cannot be performed correctly. The deviation between the focal point position of visible light and that of infrared rays can be known at the lens design stage, so after detecting focus using visible light, the lens can be moved by an amount corresponding to this deviation. It is also possible to focus on infrared light using a lens, but if you do not know the ratio of visible light and infrared light included in the incident light beam, it is necessary to adjust the lens to the precise focusing position. cannot be corrected.
本発明の目的は上述した従来の欠点を除去し、
撮影光束の分光エネルギー特性がどのような分布
をしていても常に所望の波長の光に対する合焦点
位置を正確に検出し、所望の波長のピントの合つ
た像を得ることができる自動焦点調節方法を提供
しようとするものである。 The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art,
An automatic focus adjustment method that can always accurately detect the focal point position for light of a desired wavelength and obtain a focused image of the desired wavelength, regardless of the distribution of the spectral energy characteristics of the photographing light flux. This is what we are trying to provide.
本発明の自動焦点調節方法は、赤外光に対して
収差補正されていない結像光学系からの物体の像
を形成する光束の少なくとも一部を受光装置で受
光し、この受光装置で前記光束の強度分布を光電
信号に変換し、この光電信号に基づいて物体像の
結像状態を判別して結像光学系の焦点合わせを行
なうに当たり、前記物体像を形成する光束の内の
赤外領域の光による光電信号と、それ以外の波長
領域の光による光電信号とを各別に取出し、前記
受光装置に入射する総ての波長の光により検出さ
れる合焦点位置に対する所望の波長の光による合
焦点位置までの補正値を前記各別に取出した光電
信号の比率に基づいて定め、この補正値により補
正された合焦点位置へ前記結像光学系を移動させ
ることを特徴とするものである。 In the automatic focusing method of the present invention, a light receiving device receives at least a part of a light beam forming an image of an object from an imaging optical system that is not aberration-corrected for infrared light, and the light receiving device receives the light beam. In converting the intensity distribution into a photoelectric signal, determining the imaging state of the object image based on this photoelectric signal, and focusing the imaging optical system, the infrared region of the light beam forming the object image is The photoelectric signal caused by the light in the wavelength range and the photoelectric signal caused by the light in the other wavelength range are extracted separately, and the light of the desired wavelength is combined with the focused position detected by the light of all the wavelengths incident on the light receiving device. The present invention is characterized in that a correction value up to the focal position is determined based on the ratio of the photoelectric signals extracted separately, and the imaging optical system is moved to the focused position corrected by the correction value.
以下図面を参照して本発明を詳細に説明する。 The present invention will be described in detail below with reference to the drawings.
第１０図は可視光および近赤外光に対する合焦
点位置のずれを示すものである。物体２１の像を
撮影レンズ２２で形成する場合、可視光に対して
は位置F1が合焦点位置であるとすると近赤外光
に対しては位置F2が合焦点位置となる。一般的
に長波長側にゆくほど焦点位置がレンズ２２から
遠去かるので、F1とF2とのずれΔは波長によつ
て異なる。普通の赤外写真用フイルムは750〜
800nm付近に大きな感度を有しており、写真レン
ズ２２の色収差は589nmのＤ線を中心にして補正
されているので、Δを最大589nmと800nmの色収
差分だけとつてやれば可視光の合焦点位置F1か
ら赤外光の合焦位置F2に移動するとき、色収差
の補正は実用的には十分である。このように合焦
位置F1，F2が波長によつて異なるため、第１１
図ＡおよびＢに示すように評価関数値も可視光と
赤外光とではずれてくる。本発明はこのずれを自
動的に補正するものである。 FIG. 10 shows the deviation of the focal point position for visible light and near-infrared light. When an image of the object 21 is formed by the photographing lens 22, if position F1 is the focused position for visible light, position F2 is the focused position for near-infrared light. Generally, the longer the wavelength, the farther the focal point is from the lens 22, so the deviation Δ between F 1 and F 2 differs depending on the wavelength. Ordinary infrared photographic film costs 750~
It has great sensitivity around 800 nm, and the chromatic aberration of the photographic lens 22 is corrected around the D line of 589 nm, so if you set Δ to the maximum chromatic aberration of 589 nm and 800 nm, you can focus the visible light. When moving from position F 1 to infrared light focusing position F 2 , correction of chromatic aberration is practically sufficient. In this way, since the focusing positions F 1 and F 2 differ depending on the wavelength, the 11th
As shown in Figures A and B, the evaluation function values also differ between visible light and infrared light. The present invention automatically corrects this deviation.
第１２図は本発明による自動焦点調節方法を実
施する装置の一例の構成を示すものであり、第１
３図は受光装置を示す斜視図である。物体２１の
像をレンズ２２で受光装置２３上に形成するが、
本例ではこの受光装置には半透過面２４および全
反射面２５を有する光路分割プリズム２６と、基
板２７上に設けた第１および第２の受光素子列２
８および２９とを設ける。このようにして物体２
１の同一部分の像を受光素子列２８，２９に形成
することができる。レンズ２２から第１および第
２の受光素子列２８，２９に到る光路長は差があ
り、これら受光素子列の中間の位置が予定の結像
面、例えばフイルム面と共役な結像面となつてお
り、第１および第２の受光素子列はこの結像面の
前後に配置されている。この構成は第１図に示し
た従来のものと同じである。本発明においては、
これら第１および第２の受光素子列には総ての波
長の光が入射するようにする。さらに第１３図に
示すように基板２７上に第１および第２の補助受
光素子３０および３１を配置し、これら補助受光
素子上にはそれぞれ可視光（400〜650nm）を透
過し、赤外光をカツトする赤外カツトフイルタ３
２および近赤外光（700〜800nm）を透過し、可
視光をカツトする赤外透過フイルタ３３を配置す
る。したがつてこれら補助受光素子３０および３
１からは、レンズ２２からの光束中に含まれる可
視光および近赤外光の光量を表わす信号が各別に
出力されることになる。この場合、入射光束がフ
ラツトな分光強度特性を有するときには補助受光
素子３０および３１の出力がほぼ等しくなるよう
に構成するのが好適である。また、補助受光素子
３０，３１は全波長域の光を受光する受光素子列
２８および２９と同じ分光感度特性を有するのが
望ましく、例えば基板２７をシリコンウエフアと
するときは総ての受光素子をこのウエフア内に一
体的に形成するのが望ましい。第６図に示すよう
に近赤外域においてピークを有するシリコンホト
ダイオードによつて総ての受光素子を構成する場
合、合焦検出用受光素子列２８，２９により得ら
れる合焦信号に基づくレンズの停止位置もシリコ
ンの波長依存性の影響が現われる。すなわち、フ
ラツトな分光強度を有する可視光束が受光される
ときは、光軸上の赤い光の焦束点が合焦点位置と
看做され、フラツトな特性の赤外光が入射すると
きは800nm付近の近赤外線の焦束点が合焦位置と
看做される。一方、可視光と赤外光が混在する光
束が入射するときには、これらの中間の位置が合
焦点位置と看做される。したがつて補助受光素子
３０および３１上に設けるフイルタ３２および３
３は、その透過波長域においてフラツトな分光特
性を有するものがよい。一方、フラツトな分光特
性の光が入射したときに可視光検出用の補助受光
素子３２の出力と赤外光検出用の補助受光素子３
３の出力力とを互に等しくするためには、赤外カ
ツトフイルタ３２と赤外透過フイルタ３３の透過
率比を一定にするか、またはこれらの透過率を等
しくし、補助受光素子３２および３３の出力信号
を処理する回路に増幅器を設け、両出力信号に対
する増幅率を変えて最終的な出力信号の利得が
１：１となるようにすればよい。 FIG. 12 shows the configuration of an example of an apparatus for carrying out the automatic focusing method according to the present invention.
FIG. 3 is a perspective view showing the light receiving device. An image of the object 21 is formed on the light receiving device 23 by the lens 22,
In this example, this light-receiving device includes an optical path splitting prism 26 having a semi-transmissive surface 24 and a total reflection surface 25, and first and second light-receiving element arrays 2 provided on a substrate 27.
8 and 29 are provided. In this way, object 2
1 can be formed on the light receiving element arrays 28 and 29. The optical path lengths from the lens 22 to the first and second light-receiving element arrays 28 and 29 are different, and the intermediate position between these light-receiving element arrays is the intended imaging plane, for example, an imaging plane conjugate with the film surface. The first and second light-receiving element rows are arranged in front of and behind this imaging plane. This configuration is the same as the conventional one shown in FIG. In the present invention,
Light of all wavelengths is made to enter these first and second light receiving element arrays. Furthermore, as shown in FIG. 13, first and second auxiliary light receiving elements 30 and 31 are arranged on the substrate 27, and each of these auxiliary light receiving elements transmits visible light (400 to 650 nm) and infrared light. Infrared cut filter 3
2 and an infrared transmitting filter 33 that transmits near infrared light (700 to 800 nm) and cuts visible light. Therefore, these auxiliary light receiving elements 30 and 3
1, signals representing the amount of visible light and near-infrared light contained in the light beam from the lens 22 are output separately. In this case, when the incident light beam has flat spectral intensity characteristics, it is preferable to configure the auxiliary light receiving elements 30 and 31 so that their outputs are approximately equal. Further, it is desirable that the auxiliary light receiving elements 30 and 31 have the same spectral sensitivity characteristics as the light receiving element arrays 28 and 29 that receive light in the entire wavelength range.For example, when the substrate 27 is a silicon wafer, all the light receiving elements is preferably formed integrally within the wafer. As shown in FIG. 6, when all light-receiving elements are composed of silicon photodiodes having a peak in the near-infrared region, the lens is stopped based on the focus signal obtained by the focus detection light-receiving element rows 28 and 29. The influence of the wavelength dependence of silicon also appears in the position. In other words, when visible light flux with flat spectral intensity is received, the focal point of red light on the optical axis is considered to be the focal point position, and when infrared light with flat characteristics is incident, the focal point is around 800 nm. The focal point of the near-infrared rays is considered to be the focal position. On the other hand, when a light flux containing a mixture of visible light and infrared light is incident, a position between these is considered to be a focused position. Therefore, the filters 32 and 3 provided on the auxiliary light receiving elements 30 and 31
3 preferably has flat spectral characteristics in its transmission wavelength range. On the other hand, when light with flat spectral characteristics is incident, the output of the auxiliary light receiving element 32 for detecting visible light and the output of the auxiliary light receiving element 3 for detecting infrared light
In order to equalize the output powers of the infrared cut filter 32 and the infrared transmission filter 33, the transmittance ratio of the infrared cut filter 32 and the infrared transmission filter 33 should be made constant, or the transmittances of these should be made equal, and the auxiliary light receiving elements 32 and 33 should be made equal in transmittance. An amplifier may be provided in a circuit that processes the output signal, and the amplification factors for both output signals may be changed so that the gain of the final output signal is 1:1.
上述したようにレンズ２２の色収差は赤外線に
対しては補正されておらず、可視光に対する合焦
点に対して近似的に波長に比例して増えていくと
考えてよい。今、589nmの可視光に対する合焦点
位置と、800nmの赤外線に対する合焦点位置との
ずれをΔとする。また、補助受光素子３０の出力
信号、すなわち可視光の出力信号をIVとし、補助
受光素子３１の出力信号、すなわち赤外光の出力
信号をIRとすると、赤外線に対するピント補正量
ｄは、
ｄ＝Δ×IR／IVただしIR／IV≦１のとき
ｄ＝Δ ただしIR／IV＞１のとき
とすることができる。このようにして求めた補正
値に基づいて、第１および第２の受光素子列２お
よび２９によつて求められる合焦点位置を補正す
ることにより、所望の波長の光に対する合焦点位
置へレンズ２２を駆動することができる。 As described above, the chromatic aberration of the lens 22 is not corrected for infrared rays, and can be considered to increase approximately in proportion to the wavelength of the focal point for visible light. Now, let Δ be the difference between the focal point position for 589 nm visible light and the focal point position for 800 nm infrared rays. Further, if the output signal of the auxiliary light receiving element 30, that is, the output signal of visible light, is I V , and the output signal of the auxiliary light receiving element 31, that is, the output signal of infrared light, is I R , the focus correction amount d for infrared rays is: d=Δ×I R /I V where I R /I V ≦1 d=Δ where I R /I V >1. Based on the correction value obtained in this way, the lens 22 moves to the focused point position for light of the desired wavelength by correcting the focused point position obtained by the first and second light receiving element arrays 2 and 29. can be driven.
第１４図は本発明の自動焦点調節方法に用いる
受光装置の他の実施例を示すものである。上述し
た例においては、合焦付近においては、物体２１
のほぼピントの合つた像が受光素子上に形成され
るようになるが、合焦検出用の受光素子列２８，
２９と入射光束の分光特性を検出するための受光
素子３０，３１とは物体の異なる部分の像を受光
する可能性があり、検出精度が劣化する恐れがあ
る。第１４図に示す例では、基板２７に形成した
受光素子３０，３１の上にフイルタ３２，３３を
配置し、さらにその上に拡散板３４，３５を配置
して上述した劣化を緩和するようにしている。 FIG. 14 shows another embodiment of the light receiving device used in the automatic focusing method of the present invention. In the example described above, near the focus, the object 21
A nearly in-focus image is formed on the light receiving element, but the light receiving element array 28 for focus detection,
29 and the light-receiving elements 30 and 31 for detecting the spectral characteristics of the incident light beam may receive images of different parts of the object, and there is a possibility that detection accuracy may deteriorate. In the example shown in FIG. 14, filters 32 and 33 are placed above the light receiving elements 30 and 31 formed on the substrate 27, and diffusers 34 and 35 are further placed above them to alleviate the above-mentioned deterioration. ing.
第１５図は本発明の自動焦点調節方法に用いる
受光装置のさらに他の実施例を示すものであり、
本例では分光特性検出用の受光素子３６を１個設
ける。この受光素子３６は第１６図に示すような
シリコンの三層構造を有しており、領域３６ａ，
３６ｂ，３６ｃにそれぞれ電極３７ａ，３７ｂ，
３７ｃを設けたものである。このような素子では
青色光はシリコンの表面近傍で吸収され、赤色光
は中間部で吸収され、赤外光は深い部分で吸収さ
れる。したがつて、第１７図に示すように浅い所
に位置する第１のホトダイオード３６ａ，３６ｂ
は短波長域で感度が高くなり、深い所に位置する
第２ホトダイオード３６ｂ，３６ｃは長波長域で
感度が高くなる。したがつてこれら第１および第
２のホトダイオードを、前例の受光素子３０およ
び３１の代りに用いることによつて前例と同様の
補正ができる。ただし本例では赤外域での感度の
ピークは870nmにあるので589nmの可視光に対す
る合焦点位置と、870nmの近赤外光に対する合焦
点位置との間のずれを上述のΔとして採用すれば
よい。 FIG. 15 shows still another embodiment of the light receiving device used in the automatic focusing method of the present invention,
In this example, one light receiving element 36 for detecting spectral characteristics is provided. This light receiving element 36 has a three-layer structure of silicon as shown in FIG.
Electrodes 37a, 37b, 36b, 36c, respectively
37c. In such devices, blue light is absorbed near the surface of the silicon, red light is absorbed in the middle, and infrared light is absorbed deep. Therefore, as shown in FIG.
has high sensitivity in a short wavelength range, and the second photodiodes 36b and 36c located deep have high sensitivity in a long wavelength range. Therefore, by using these first and second photodiodes in place of the light receiving elements 30 and 31 in the previous example, the same correction as in the previous example can be performed. However, in this example, the peak of sensitivity in the infrared region is at 870 nm, so the deviation between the focal point position for visible light at 589 nm and the focal point position for near-infrared light at 870 nm can be used as the above Δ. .
本発明は上述した実施例だけに限定されるもの
ではなく、幾多の変形が可能である。例えば光量
が不足したとき、例えば暗い中で撮影するときに
合焦信号を得ようとする場合の一つの方法として
赤外線を物体に照射する方法がある。このような
方法は合焦検出用受光素子列の光路中へ赤外カツ
トフイルタを挿入した装置では採用できないが、
赤外カツトフイルタを設けなければ、赤外光だけ
でなく可視光も入射するので正確な合焦信号を得
ることはできない。しかし、本発明では上述した
ように赤外光と可視光とを各別に検出し、これに
より合焦点位置の補正を行なうものであるから上
述したような場合に特に有効である。さらに上述
した実施例では予定の結像面の前後にそれぞれ受
光素子列を配置し、これら受光素子列から得られ
評価関数値を比較するいわゆるぼけ像検出方式に
適用したが、特開昭48―60645号、特開昭51―
147317号等に記載されているように撮影レンズの
像側に受光素子列を配置し、デフオーカスによる
主光線の像面に対する横ずれを検出する方式にも
本発明は有効に適用することができる。また上述
した例では可視光写真撮影を行なう場合に赤外光
の影響を補正するようにしたが、赤外写真撮影を
行なう場合の可視光の影響を補正することもで
き、この場合には上述した補正量を逆向きにすれ
ばよい。 The present invention is not limited to the embodiments described above, but can be modified in many ways. For example, one method for obtaining a focusing signal when the amount of light is insufficient, for example when photographing in the dark, is to irradiate an object with infrared rays. Although this method cannot be used in a device that has an infrared cut filter inserted into the optical path of the focus detection photodetector array,
If an infrared cut filter is not provided, not only infrared light but also visible light will be incident, making it impossible to obtain an accurate focusing signal. However, in the present invention, as described above, infrared light and visible light are detected separately, and the in-focus position is corrected thereby, so that the present invention is particularly effective in the above-mentioned cases. Furthermore, in the above-mentioned embodiment, a so-called blurred image detection method was applied in which light-receiving element arrays were placed before and after the intended image-forming plane, and the evaluation function values obtained from these light-receiving element arrays were compared. No. 60645, Japanese Patent Publication No. 1973-
The present invention can also be effectively applied to a method of arranging a light receiving element array on the image side of a photographic lens and detecting a lateral shift of a principal ray with respect to an image plane due to a defocus, as described in No. 147317 and the like. Furthermore, in the above example, the influence of infrared light is corrected when taking visible light photographs, but it is also possible to correct the influence of visible light when taking infrared photographs. The corrected amount can be reversed.
上述した本発明の効果を要約すると次の通りで
ある。 The effects of the present invention described above are summarized as follows.
(1) 色収差分だけレンズ駆動量を自動的に補正す
ることができるので入射光束の分光特性によら
ずに所望の波長の光に対する合焦位置に調節す
ることができる。(1) Since the lens drive amount can be automatically corrected by the amount of chromatic aberration, it is possible to adjust the focus position for light of a desired wavelength regardless of the spectral characteristics of the incident light beam.
(2) 合焦検出用の受光装置には赤外カツトフイル
タを設けないので赤外光を利用することがで
き、検出感度および精度を向上することができ
る。(2) Since the light receiving device for focus detection is not provided with an infrared cut filter, infrared light can be used, and detection sensitivity and accuracy can be improved.
(3) 赤外線写真の撮影を行なう場合には色収差補
正を逆向きにすれば自動焦点が可能であり、従
来の人間の眼による合焦検出法よりも簡単に行
なうことができる。(3) When taking infrared photographs, automatic focusing is possible by reversing chromatic aberration correction, which is easier than the conventional focus detection method using the human eye.
(4) 合焦検出用受光素子と分光特性検出用受光素
子とを同一基板上に形成すると、両素子の分光
感度特性が揃うので合焦精度が向上すると共に
製造も容易で安価となる。(4) When the light-receiving element for focus detection and the light-receiving element for spectral characteristic detection are formed on the same substrate, the spectral sensitivity characteristics of both elements are matched, which improves the focusing accuracy and also makes manufacturing easier and cheaper.
第１図は従来のぼけ像検出方式になる合焦検出
方法を示す線図、第２図は同じくそのときのレン
ズの移動に伴う受光素子列上の像のぼけ具合を示
す線図、第３図は同じくそのときの受光素子の出
力を示すグラフ、第４図は同じくそのときのレン
ズ移動量と評価値との関係を示すグラフ、第５図
は従来の自動焦点調節装置の構成を示すブロツク
図、第６図はシリコンホトダイオードの分光感度
特性を示すグラフ、第７図、第８図および第９図
はそれぞれ太陽光、フラツドランプおよび螢光灯
の分光強度特性を示すグラフ、第１０図は本発明
による自動焦点調節方式における可視合焦点位置
および近赤外合焦点位置を説明するための線図、
第１１図はレンズの色収差による評価値のずれを
示す線図、第１２図は本発明の自動焦点調節方法
による合焦検出装置の一例の構成を示す線図、第
１３図は同じくその受光装置の一例の構成を示す
斜視図、第１４図は同じくその受光装置の他の例
の構成を示す線図的断面図、第１５図は同じくそ
の受光装置のさらに他の例の構成を示す斜視図、
第１６図は同じくその分光特性検出用受光装置の
構成を示す断面図、第１７図は同じくその分光感
度特性を示すグラフである。
２１…物体、２２…撮影レンズ、２３…受光装
置、２７…基板、２８，２９…合焦検出用受光素
子列、３０，３１…分光特性検出用受光素子、３
２…赤外カツトフイルタ、３３…赤外透過フイル
タ、３４，３５…拡散板、３６…分光特性検出用
受光素子。
Fig. 1 is a diagram showing the focus detection method which is a conventional blur image detection method, Fig. 2 is a diagram showing the degree of blurring of the image on the light receiving element row due to the movement of the lens at that time, and Fig. 3 The figure is a graph showing the output of the light receiving element at that time, Figure 4 is a graph showing the relationship between the lens movement amount and evaluation value at that time, and Figure 5 is a block diagram showing the configuration of a conventional automatic focus adjustment device. Figure 6 is a graph showing the spectral sensitivity characteristics of a silicon photodiode, Figures 7, 8, and 9 are graphs showing the spectral intensity characteristics of sunlight, flat lamp, and fluorescent lamp, respectively, and Figure 10 is a graph showing the spectral sensitivity characteristics of a silicon photodiode. A diagram for explaining the visible focus position and the near-infrared focus position in the automatic focus adjustment method according to the invention,
FIG. 11 is a diagram showing deviations in evaluation values due to lens chromatic aberration, FIG. 12 is a diagram showing the configuration of an example of a focus detection device using the automatic focus adjustment method of the present invention, and FIG. 13 is a diagram showing the light receiving device thereof. FIG. 14 is a schematic cross-sectional view showing the structure of another example of the light receiving device; FIG. 15 is a perspective view showing the structure of still another example of the light receiving device. ,
FIG. 16 is a sectional view showing the configuration of the light receiving device for detecting spectral characteristics, and FIG. 17 is a graph showing the spectral sensitivity characteristics. 21... Object, 22... Photographing lens, 23... Light receiving device, 27... Substrate, 28, 29... Light receiving element array for focus detection, 30, 31... Light receiving element for spectral characteristic detection, 3
2... Infrared cut filter, 33... Infrared transmission filter, 34, 35... Diffusion plate, 36... Light receiving element for detecting spectral characteristics.
Claims (1)
少なくとも一部を受光装置で受光し、この受光装
置で前記光束の強度分布を光電信号に変換し、こ
の光電信号に基いて物体像の結像状態を判別して
結像光学系の焦点合わせを行なうに当り、 前記物体像を形成する光束の赤外領域の光によ
る光電信号と、それ以外の波長領域の光による光
電信号とを各別に取出し、 前記受光装置に入射する総ての波長の光により
検出される合焦点位置に対する所望の波長の光に
よる合焦点位置までの補正値を前記各別に取出し
た光電信号の比率に基づいて定め、 この補正値により補正された合焦点位置へ前記
結像光学系を移動させることを特徴とする自動焦
点調節方法。 ２ 前記赤外領域の光およびそれ以外の波長領域
の光の光電信号を各別に取出す補助受光手段と、
総ての波長の光を受光する前記受光装置とを同一
基板上に形成したことを特徴とする特許請求の範
囲第１項記載の自動焦点調節方法。[Scope of Claims] 1. At least a part of the light beam from the imaging optical system that forms an image of an object is received by a light receiving device, the light receiving device converts the intensity distribution of the light beam into a photoelectric signal, and the photoelectric signal is converted into a photoelectric signal. When determining the imaging state of the object image based on the image formation state and focusing the imaging optical system, a photoelectric signal from the light in the infrared region of the luminous flux forming the object image and light in the other wavelength region are used. and a photoelectric signal obtained by extracting each of the photoelectric signals separately, and a correction value for the focused point position detected by the light of all wavelengths incident on the light receiving device to the focused point position by the light of the desired wavelength. An automatic focusing method characterized in that the imaging optical system is moved to a focal point position that is determined based on a ratio of the correction value and that is corrected by the correction value. 2. auxiliary light receiving means for separately extracting the photoelectric signals of the light in the infrared region and the light in other wavelength regions;
2. The automatic focusing method according to claim 1, wherein the light receiving device that receives light of all wavelengths is formed on the same substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15921381A JPS5859413A (en) | 1981-10-06 | 1981-10-06 | Autofocusing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15921381A JPS5859413A (en) | 1981-10-06 | 1981-10-06 | Autofocusing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5859413A JPS5859413A (en) | 1983-04-08 |
| JPH0145883B2 true JPH0145883B2 (en) | 1989-10-05 |
Family
ID=15688793
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15921381A Granted JPS5859413A (en) | 1981-10-06 | 1981-10-06 | Autofocusing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5859413A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008122535A (en) * | 2006-11-09 | 2008-05-29 | Canon Inc | Photometric device and camera |
| JP2008170517A (en) * | 2007-01-09 | 2008-07-24 | Canon Inc | Focusing device, its control method, and imaging apparatus |
| US7414231B2 (en) | 2004-09-29 | 2008-08-19 | Canon Kabushiki Kaisha | Focus-state detecting device, image sensing apparatus and image sensing system having same and lens unit mounted thereon |
| US8063977B2 (en) | 2006-11-16 | 2011-11-22 | Canon Kabushiki Kaisha | Photosensor and focus detecting device |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6286318A (en) * | 1985-10-11 | 1987-04-20 | Minolta Camera Co Ltd | Focus position detector |
| JPS62192716A (en) * | 1986-02-20 | 1987-08-24 | Minolta Camera Co Ltd | Focus detecting device |
| JPS6341818A (en) * | 1986-08-06 | 1988-02-23 | Minolta Camera Co Ltd | Automatic focus adjusting device provided with auxiliary illuminating device |
| JP2666274B2 (en) * | 1987-03-18 | 1997-10-22 | ミノルタ株式会社 | Automatic focus detection device |
| JP4532849B2 (en) * | 2003-05-20 | 2010-08-25 | キヤノン株式会社 | Automatic focusing device |
| CN111273504B (en) * | 2020-03-26 | 2022-05-03 | 浙江大华技术股份有限公司 | Focusing processing method and device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5414232A (en) * | 1977-07-05 | 1979-02-02 | Olympus Optical Co Ltd | Method of detecting focus position depending on chromatic aberration of lens |
| JPS55111928A (en) * | 1979-02-21 | 1980-08-29 | Ricoh Co Ltd | Automatic focusing device |
-
1981
- 1981-10-06 JP JP15921381A patent/JPS5859413A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5414232A (en) * | 1977-07-05 | 1979-02-02 | Olympus Optical Co Ltd | Method of detecting focus position depending on chromatic aberration of lens |
| JPS55111928A (en) * | 1979-02-21 | 1980-08-29 | Ricoh Co Ltd | Automatic focusing device |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7414231B2 (en) | 2004-09-29 | 2008-08-19 | Canon Kabushiki Kaisha | Focus-state detecting device, image sensing apparatus and image sensing system having same and lens unit mounted thereon |
| JP2008122535A (en) * | 2006-11-09 | 2008-05-29 | Canon Inc | Photometric device and camera |
| US8063977B2 (en) | 2006-11-16 | 2011-11-22 | Canon Kabushiki Kaisha | Photosensor and focus detecting device |
| JP2008170517A (en) * | 2007-01-09 | 2008-07-24 | Canon Inc | Focusing device, its control method, and imaging apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5859413A (en) | 1983-04-08 |
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