WO2014156384A1 - Autofocus device and method for controlling operation of same - Google Patents

Autofocus device and method for controlling operation of same Download PDF

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Publication number
WO2014156384A1
WO2014156384A1 PCT/JP2014/053971 JP2014053971W WO2014156384A1 WO 2014156384 A1 WO2014156384 A1 WO 2014156384A1 JP 2014053971 W JP2014053971 W JP 2014053971W WO 2014156384 A1 WO2014156384 A1 WO 2014156384A1
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WO
WIPO (PCT)
Prior art keywords
focus
evaluation value
lens
focus lens
unit
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PCT/JP2014/053971
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French (fr)
Japanese (ja)
Inventor
江波戸　尚
隆久 佐藤
愛子 関谷
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富士フイルム株式会社
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Publication of WO2014156384A1 publication Critical patent/WO2014156384A1/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B13/00—Viewfinders; Focusing aids for cameras; Means for focusing for cameras; Autofocus systems for cameras
    • G03B13/32—Means for focusing
    • G03B13/34—Power focusing
    • G03B13/36—Autofocus systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/60—Control of cameras or camera modules
    • H04N23/67—Focus control based on electronic image sensor signals
    • 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
    • G02B7/34—Systems for automatic generation of focusing signals using different areas in a pupil plane
    • 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

Definitions

  • the present invention relates to an auto-focus device and an operation control method thereof.
  • the camera auto focus is roughly divided into phase difference AF and contrast AF.
  • phase difference AF light entering from a lens is divided into two parts and guided to a sensor for phase difference AF, and the direction and amount of focus are determined from two intervals formed.
  • Contrast AF is also placed at a position where the optical path length difference is different from that in which the focus lens is searched for a high contrast while moving the focus lens based on the image captured on the image sensor (focused image AF).
  • contrast AF optical path length difference AF
  • the optical path length difference AF is used. Both phase-difference AF and contrast AF are provided, and the most suitable AF is selected according to the subject's change and shooting conditions, preventing focus control in the wrong direction and unnecessary blurring. There is a thing to do (patent document 1).
  • Contrast AF can position the focus lens at the in-focus position with high accuracy, but the positioning range is limited to when the focus lens is within the allowable positioning range near the in-focus position. Positioning cannot be performed when there is a focus lens.
  • phase difference AF even if the focus lens is located far away from the in-focus position, it can be driven to the in-focus position, but the focus lens is not very accurately positioned at the in-focus position. is not.
  • Cited Document 1 it is not considered to make use of such features of the AF method.
  • An object of the present invention is to position the focus lens at the in-focus position by making use of the features of contrast AF and phase difference AF.
  • the autofocus device is based on the amount of focus deviation in the pupil division direction of the two subject images formed by dividing the light incident through the focus lens into two by pupil division.
  • a first in-focus evaluation value output unit for outputting a first in-focus evaluation value signal, and a first imaging in which optical path lengths are arranged at different positions in an optical path of light incident through a focus lens
  • a second focus evaluation value signal indicating a focus shift amount based on the output signal of the element, the second image sensor, the output signal of the first image sensor, and the output signal of the second image sensor.
  • the focus evaluation value output unit Output first focus evaluation value
  • the focus lens is moved based on the signal, and the second focus evaluation output from the second focus evaluation value output unit when the focus lens is closer to the position where the subject image is focused than the threshold position.
  • the focus lens is positioned at the position where the subject image is in focus based on the value signal, and the position where the focus lens is positioned by the focus lens movement unit is the focus.
  • the first position determination unit and the first position determination unit for determining whether or not the position of the lens is based on the first focus evaluation value signal output from the first focus evaluation value output unit.
  • a first movement control unit for controlling the focus / lens moving unit to move the focus / lens based on the first focusing evaluation value signal output from the first focusing evaluation value output unit. It is characterized by being.
  • the present invention also provides an operation control method suitable for an autofocus device. That is, in this method, the first focus evaluation value output unit shifts the position in the pupil division direction of two subject images formed by dividing the light incident through the focus lens into two by pupil division. A first focus evaluation value signal indicating the amount of focus shift based on the amount of light, and the second focus evaluation value output unit has optical path lengths in the optical paths of light incident through the focus lens.
  • a second focus evaluation value signal indicating a focus shift amount is output, and the focus / lens moving unit
  • the first focus evaluation value output unit outputs the first focus evaluation value when the position of the focus lens is far from the position where the subject image is in focus beyond the threshold value near the position where the subject image is in focus.
  • the focus evaluation value signal of If the focus lens is moved and the focus lens is closer to the position where the subject image is in focus than the threshold value position it is based on the second focus evaluation value signal output from the second focus evaluation value output unit.
  • the focus lens is positioned at the position where the subject image is in focus, and the position where the focus lens is positioned by the focus lens moving unit is the position of the focus lens where the subject image is focused. Is determined based on the first focus evaluation value signal output from the first focus evaluation value output unit, and the movement control unit uses the first position determination unit to focus the focus / lens moving unit. In response to determining that the position where the lens is positioned is not the position of the focus lens at which the subject image is in focus, the first focus evaluation value output unit outputs the first focus output value. Based on the focus evaluation value signal is for controlling the focus lens moving unit to move the focus lens.
  • the first AF sensor that can move the focus lens relatively quickly is not high in accuracy until the focus lens reaches a threshold position near the position where the subject image is focused.
  • the focus lens is moved on the basis of the first focus evaluation value signal output from.
  • the second AF sensor output from the second AF sensor that cannot be quickly moved but can be positioned at the focus position with high accuracy.
  • the focus lens is moved based on the in-focus evaluation value signal and positioned at the in-focus position.
  • the second focus evaluation value signal output from the second AF sensor may be determined to be positioned at the focus position when the focus lens is outside the allowable range. For this reason, if the imaging lens changes and the focus lens continues to position the focus lens based on the second focus evaluation value signal output from the second AF sensor, the focus lens is within the allowable range. It may be determined that the lens is positioned at the in-focus position even though it is not positioned at the in-focus position, and the in-focus state may not be achieved. For this reason, when the focus lens is moved based on the second focus evaluation value signal output from the second AF sensor and positioned at the focus position, the first AF sensor output from the first AF sensor.
  • the position of the focus lens positioned based on the second focus evaluation value signal output from the second AF sensor based on the first focus evaluation value signal is a position where the subject image is in focus If it is determined that the position is not such a position, the focus lens is moved based on the first focus evaluation value signal output from the first AF sensor. As a result, even if the focus lens is positioned based on the second focus evaluation value signal output from the second AF sensor due to a scene change or the like, it cannot be positioned at the focus position. It becomes possible to position in the focal position.
  • a second movement control unit that controls the focus / lens moving unit to move the focus / lens may be further provided.
  • the first focus evaluation output from the first focus evaluation value output unit in response to the focus lens moving toward the position where the subject image is focused and reaching the threshold position.
  • the focus lens position where the subject image determined based on the value signal is in focus and the subject image determined based on the second focus evaluation value signal output from the second focus evaluation value output unit A second position determining unit that determines whether or not the position of the focus lens to be matched may be further included.
  • the focus / lens moving unit outputs the second focus evaluation value signal output from the second focus evaluation value output unit in response to the determination that the second position determination unit matches.
  • the focus lens will be positioned at the position where the subject image is in focus.
  • the first focus evaluation value signal or the second focus evaluation value signal output from the first focus evaluation value output unit After the focus lens is positioned at a position where the subject image is in focus by the focus / lens moving unit, the first focus evaluation value signal or the second focus evaluation value signal output from the first focus evaluation value output unit. Focusing is performed based on the first focus evaluation value signal output from the first focus evaluation value output unit in response to a change in the second focus evaluation value signal output from the focus evaluation value output unit.
  • the position of the lens is farther from the in-focus position than the threshold position, and is expressed by the focus lens moving direction and the second in-focus evaluation value signal represented by the first in-focus evaluation value signal.
  • the first determination unit that determines whether or not the movement direction of the focus lens is coincident, and the position of the focus lens is farther from the in-focus position than the threshold position by the first determination unit.
  • a third movement control unit for controlling the focus lens moving unit to move the focus lens based on the first focusing evaluation value signal output from the first focusing evaluation value output unit. Further, it may be provided.
  • the first focus evaluation value signal or the second focus evaluation value signal output from the first focus evaluation value output unit After the focus lens is positioned at a position where the subject image is in focus by the focus / lens moving unit, the first focus evaluation value signal or the second focus evaluation value signal output from the first focus evaluation value output unit. Focusing is performed based on the first focus evaluation value signal output from the first focus evaluation value output unit in response to a change in the second focus evaluation value signal output from the focus evaluation value output unit.
  • the lens position is closer to the in-focus position than the threshold position, and is expressed by the focus lens moving direction and the second in-focus evaluation value signal represented by the first in-focus evaluation value signal.
  • the position of the focus lens is closer to the in-focus position than the threshold value position by the second determination section that determines whether or not the movement direction of the focus lens is not matched, and the second determination section.
  • a fourth movement control unit for controlling the focus lens moving unit to move the focus lens based on the second focus evaluation value signal output from the second focus evaluation value output unit. May be.
  • the structure of an imaging lens unit is shown.
  • the relationship between the image sensor for optical path length difference AF and the imaging position of a subject image is shown.
  • the relationship between the AF evaluation value and the focus / lens position is shown.
  • the relationship between the phase difference AF evaluation value and the focus / lens position is shown.
  • the relationship between the differential AF evaluation value and the focus / lens position is shown. It is a flowchart which shows a focusing process procedure. It is a flowchart which shows a focusing process procedure.
  • FIG. 1 shows an embodiment of the present invention, and shows an optical configuration of a part of a photographing lens unit 1 and a camera body 20 used for broadcasting or the like.
  • the taking lens unit 1 is detachably attached to the camera body 20.
  • the photographic lens unit 1 includes a focus lens (focus lens group) 2, a zoom lens (zoom lens group) 3, and a front relay so as to have an optical axis common to the optical axis O1 of the photographic lens unit 1
  • a lens (front relay / lens group) 5 and a rear relay / lens (rear relay / lens group) 7 are included.
  • a diaphragm 4 is arranged between the zoom lens 3 and the front relay lens 5 so that the optical axis O1 of the photographing lens unit 1 passes through the center.
  • a half mirror 6 is arranged between the front relay lens 5 and the rear relay lens 7.
  • the camera body 20 is provided with a color separation prism 21 having an optical axis common to the optical axis O1 of the photographing lens unit 1 when the photographing lens unit 1 is mounted.
  • the color separation prism 21 includes a first prism 22, a second prism 23, and a third prism 24, and incident light is separated into a red component, a green component, and a blue component.
  • An imaging CCD 26 and a third imaging CCD 27 are arranged.
  • the photographing lens unit 1 includes an AF relay lens (AF relay lens) that uses a part of the light reflected at the center of the half mirror 6 as an optical axis [optical axis for AF (auto focus)] O2.
  • Lens group 8 is provided.
  • a half mirror 40 (which may be a reflecting prism) is provided downstream of the AF relay lens 8.
  • a total reflection mirror 9 is provided after the half mirror 40.
  • An optical path length difference AF sensor 55 is provided in the total reflection direction of the total reflection mirror 9.
  • the optical path length difference AF sensor 55 includes a split prism 10 composed of a first prism 11 and a second prism 12.
  • a first AF CCD 13 and a second AF CCD 14 are provided on the exit surface of the first prism 11 and the exit surface of the second prism 12, respectively.
  • the light beam incident on the photographic lens unit 1 passes through the focus lens 2, zoom lens 3, aperture 4, front relay lens 5, half mirror 6 and rear relay lens 7, and enters the camera body 20. Led.
  • the light beam is decomposed into a red light component, a green light component, and a blue light component, respectively, and the first image pickup CCD 25, the second image pickup CCD 26, and the third image pickup device.
  • a subject image is formed on each of the CCDs 27 for use.
  • Video signals representing subject images of the red light component, the green light component, and the blue light component are output from the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27, respectively.
  • the light beam incident on the taking lens unit 1 is partially reflected by the half mirror 6.
  • the light beam reflected by the half mirror 6 passes through the AF relay lens 8 and is guided to the half mirror 40.
  • a part of the light incident on the half mirror 40 is reflected and incident on the phase difference sensor 41 included in the phase difference AF sensor 45.
  • the phase difference sensor 41 includes a condenser lens, a separator lens, and an image sensor (all not shown).
  • the light incident on the phase difference sensor 41 is condensed by the condenser lens and divided into two by the separator lens.
  • the light divided into two forms an image on the image sensor as two images.
  • the focus lens 2 can be controlled so that the focus lens 2 is focused from the interval between the two images.
  • the phase difference sensor 41 outputs video signals representing two images, and the evaluation value calculation circuit 42 generates a phase difference AF evaluation value representing the degree of focusing of the subject image obtained by imaging.
  • a signal representing the phase difference AF evaluation value (first focus evaluation value signal) is input to the selector 33 via the amplifier circuit 43.
  • the light transmitted through the half mirror 40 is totally reflected by the total reflection mirror 9.
  • the light beam totally reflected by the total reflection mirror 9 is incident on the splitting prism 10 included in the optical path length difference AF sensor 55, a part is incident on the first optical path length difference AF CCD 13, and the rest is the second optical path length.
  • the light enters the CCD 14 for difference AF.
  • An AF signal is output from each of the first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14.
  • Signals output from the first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14 are input to the evaluation value calculation circuits 51 and 52, respectively, and indicate the degree of focusing of the focus lens 2. Is evaluated. Signals representing the evaluation values calculated in the evaluation value calculation circuits 51 and 52 are supplied to the subtraction circuit 53. The signal representing the evaluation value calculated in the evaluation value calculating circuit 52 is subtracted in the subtracting circuit 53 from the signal representing the evaluation value calculated in the evaluation value calculating circuit 51 to obtain a differential AF evaluation value. A signal representing the differential AF evaluation value (second focus evaluation value signal) is amplified by the amplifier circuit 54 and is supplied to the selector 33.
  • the phase difference AF evaluation value signal output from the amplifier circuit 43 and the difference AF evaluation value signal output from the amplifier circuit 54 are also input to the switching control circuit 31.
  • the selector 33 is controlled based on the input phase difference AF evaluation value signal and the difference AF evaluation value signal, and the phase difference AF evaluation value signal output from the amplifier circuit 43 or the difference AF evaluation value signal output from the amplifier circuit 54 Either one is supplied to the gain control amplification circuit 34.
  • the gain control amplification circuit 34 the input signal is amplified and applied to the focus motor 35 as a control signal representing the rotation direction and the rotation speed.
  • the focus lens 2 is moved by the focus motor 35.
  • FIG. 2 shows the relationship between the optical distances of the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF CCD 14. Is shown.
  • An optical system for causing light to enter the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF CCD 14 is provided. Represented by lens 30.
  • the optical distances until the light enters the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27 are all equal.
  • the optical distance until the light enters the first optical path length difference AF CCD 13 is a predetermined distance from the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27.
  • the optical distance until the light enters the second optical path length difference AF CCD 14 is equal to a predetermined distance from the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27.
  • the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference so as to be equal when they are arranged after a distance.
  • the positional relationship of the AF CCD 14 (optically equidistantly spaced positions) is defined. Temporarily, the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF CCD 14 are arranged on the same optical axis. The first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14 are arranged at equally spaced positions before and after the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27. It is equivalent to what is done.
  • FIG. 3 shows the relationship between the AF evaluation value and the position of the focus lens 2.
  • a graph G51 is obtained from the evaluation value signal calculated by the evaluation value calculation circuit 51 based on the signal output from the first optical path length difference AF CCD 13, and the signal output from the second optical path length difference AF CCD 14 is obtained.
  • a graph G52 is obtained from the evaluation value signal calculated by the evaluation value calculation circuit 52 based on the above.
  • the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF are assumed to be on the same optical axis.
  • the first optical path length difference AF CCD 13 and the second optical path length difference are arranged at equal intervals before and after the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27. Since this is equivalent to the arrangement of the AF CCD 14, at the intersections of the graphs G51 and G52 obtained from the signals of the first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14, respectively.
  • a certain focus lens position P0 is the position of the focus lens 2 where the subject image is focused on the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27.
  • FIG. 4 shows the relationship between the phase difference AF evaluation value and the position of the focus lens 2.
  • the horizontal axis indicates the position of the focus lens 2, and the vertical axis indicates the phase difference AF evaluation value.
  • the position of the focus lens 2 is determined from the relationship between the calculated phase difference AF evaluation value and the graph G0. For example, if the phase difference AF evaluation value calculated by the evaluation value calculation circuit 42 is D21 or D22, the position of the focus lens 2 is P11 or P12. If the phase difference AF evaluation value is 0, the position P0 of the focus lens 2 is substantially equal to the in-focus position at which the subject image is in focus. By moving the focus lens 2 so that the phase difference AF evaluation value becomes 0, the subject image is brought into focus.
  • the relationship between the AF evaluation value and the focus lens 2 is a stepped graph 0, and when the phase difference AF evaluation value is 0, the focus position P0 may not correspond completely.
  • threshold positions P1 and P2 in the vicinity of the focus position P0 are defined, and the focus lens 2 is located outside these threshold positions P1 and P2 (from the focus position P0).
  • the phase difference evaluation value is used (phase difference AF use range) as shown in FIG.
  • the focus lens 2 is positioned using the differential AF evaluation value shown in FIG. 5 (optical path length difference AF use range).
  • FIG. 5 is a graph G53 showing the relationship between the differential AF evaluation value signal output from the subtraction circuit 53 and the position of the focus lens 2.
  • the horizontal axis is the focus lens position, and the vertical axis is the differential AF evaluation value.
  • the positional relationship between the differential AF evaluation value and the focus lens 2 corresponds one to one. If the differential AF evaluation value is known, the position of the focus lens 2 between the position P11 of the focus lens 2 corresponding to the positive peak value D11 and the position P12 of the focus lens 2 corresponding to the negative peak value D12. I understand. The position of the focus lens 2 at which the differential AF evaluation value is 0 is the in-focus position.
  • the difference AF evaluation value indicates the difference between the graphs G51 and G52, and the focus lens 2 position P11 indicated by the positive peak value D11 and the focus peak indicated by the negative peak value D12. If there is no focus lens 2 between the lens 2 and the position P12, the focus lens 2 cannot be positioned at the focus position P0.
  • the distance between the position P11 and the position P12 is called an optical path length difference AF possible range based on the optical path length difference AF sensor 55. Further, in this embodiment, as described above, the range is within the optical path length difference AF possible range and between the first threshold value position P1 and the second threshold value position P2 near the in-focus position P0.
  • the focus lens 2 is positioned using the phase difference AF evaluation value obtained from the phase difference sensor 45 until the phase difference AF usage range is entered, but when the focus lens 2 enters the phase difference AF usage range.
  • the focus lens 2 is positioned using the differential AF evaluation value obtained from the optical path length difference AF sensor 55.
  • the focus lens 2 can be moved quickly by moving the focus lens 2 using the phase difference AF evaluation value obtained from the phase difference sensor 45.
  • the focus lens 2 can be accurately positioned at the in-focus position P0.
  • 6 and 7 are flowcharts showing the focusing processing procedure.
  • phase difference AF sensor 45 and the optical path length difference AF sensor 55 are driven, and based on the phase difference AF, the phase difference AF evaluation value and the optical path length difference indicating the amount of displacement from the focus position of the focus lens 2.
  • a differential AF evaluation value based on the AF is calculated (step 61).
  • the selector 34 is switched so that the focus lens 2 approaches the in-focus position P0 (step 62).
  • the phase difference AF evaluation value signal is used, since the focus lens 2 can be moved quickly, the time until focusing can be shortened. Focusing is performed using the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45 until the focus lens 2 enters the optical path length difference AF use range beyond the threshold position P1 or P2 as shown in FIG. The lens 2 is moved (NO in step 63).
  • the position of the focus lens 2 determined based on the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45 It is confirmed whether or not the position of the focus lens 2 determined based on the differential AF evaluation value signal obtained from the optical path length difference AF sensor 55 is substantially the same (step 64). If they are not substantially the same (NO in step 64), it is considered that some kind of error has occurred, and a predetermined error process is performed. However, the focus lens 2 may be moved to the in-focus position P0 using the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45.
  • the focus lens is based on the differential AF evaluation value signal obtained from the optical path length difference AF sensor 55 in order to accurately position the focus lens 2 at the in-focus position P0. 2 is moved (step 65).
  • the focus lens 2 is positioned at the focus position P0 based on the differential AF evaluation value signal (YES in step 66)
  • the phase difference AF evaluation obtained from the phase difference sensor 45 as to whether or not the focus position is correct is obtained.
  • a determination is made based on the value signal (step 67).
  • the focus / lens 2 can be positioned using the differential AF evaluation value signal obtained from the optical path length difference AF sensor 55 due to a change in the imaging scene or the like. It is considered that the focus lens 2 has moved outside the positioning allowable range. For this purpose, the focus lens 2 is moved again using the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45 (step 62).
  • step 68 If it is determined that the in-focus position is correct (YES in step 68), whether the value of the phase difference AF evaluation value signal or the value of the difference AF evaluation value signal has changed to some extent (the position of the focus lens 2 is the optical path length). It is confirmed whether or not the difference AF is out of use range (step 69).
  • the value of the phase difference AF evaluation value signal or the difference AF evaluation value signal changes to some extent (YES in step 69)
  • the moving direction of the lens 2 and the moving direction of the focus lens 2 known from the optical path length difference AF evaluation value signal are the same (step 70).
  • step 70 the focus lens 2 is moved using the phase difference AF evaluation value signal faster than the focus lens 2 is moved using the difference AF evaluation value signal. Since control is possible, the focus lens is moved again using the phase difference AF evaluation value signal (step 62).
  • the focus lens 2 is in the optical path. It is confirmed whether or not the long difference AF is possible (step 71). If the focus lens 2 is out of the optical path length difference AF possible range (YES in step 71), the focus lens 2 cannot be positioned using the differential AF evaluation value signal, so the phase difference AF evaluation value signal is used. The focus lens 2 is moved (step 62).
  • the focus control based on the optical path length difference AF sensor 55 is more reliable than the focus control based on the phase difference AF sensor 45. Therefore, focusing control based on the optical path length difference AF sensor 55 is continued as it is.

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Abstract

The purpose of the present invention is to take advantage of the characteristics of light path length difference AF and phase difference AF. A focus lens is moved using phase difference AF until the focus lens enters a range in which light path length difference AF is used. When the focus lens enters the range in which light path length difference AF is used, the focus lens is positioned in a focal position (P0) using light path length difference AF. If the focus lens is within the allowable range for focal positioning but outside of the range for light path length difference AF because of changes in the scene being imaged or the like, the focus lens is once again moved using phase difference AF.

Description

オート・フォーカス装置およびその動作制御方法Auto-focus device and operation control method thereof
　この発明は，オート・フォーカス装置およびその動作制御方法に関する。 The present invention relates to an auto-focus device and an operation control method thereof.
　カメラのオート・フォーカスは，大別して位相差ＡＦ，コントラストＡＦがある。位相差ＡＦは，レンズから入った光を二つに分けて位相差ＡＦ用のセンサに導き，結像した二つの間隔からピントの方向と量を判断するものである。コントラストＡＦは，さらに、撮像素子に写った画像をもとにフォーカス・レンズを動かしながらコントラストが大きいところを探してピントを合わせるもの（撮像画AF）と、光路長差が異なる位置に配置された二つの撮像素子で被写体を撮像し，それぞれの撮像素子から得られた画像信号にもとづいてピントを合わせるコントラストＡＦ（光路長差ＡＦ）があり、放送用テレビ・カメラに装着されるレンズのコントラストAFとしては、光路長差AFが利用される。位相差ＡＦとコントラストＡＦとの両方のＡＦが設けられており，被写体の変化や撮影状況に応じて最適なＡＦを選択し，誤った方向へのフォーカス制御や不要なボケの発生を未然に防止するというものもある（特許文献１）。 The camera auto focus is roughly divided into phase difference AF and contrast AF. In the phase difference AF, light entering from a lens is divided into two parts and guided to a sensor for phase difference AF, and the direction and amount of focus are determined from two intervals formed. Contrast AF is also placed at a position where the optical path length difference is different from that in which the focus lens is searched for a high contrast while moving the focus lens based on the image captured on the image sensor (focused image AF). There is a contrast AF (optical path length difference AF) that captures an image of a subject with two image sensors and focuses based on the image signal obtained from each image sensor, and a contrast AF of a lens mounted on a broadcast television camera As an example, the optical path length difference AF is used. Both phase-difference AF and contrast AF are provided, and the most suitable AF is selected according to the subject's change and shooting conditions, preventing focus control in the wrong direction and unnecessary blurring. There is a thing to do (patent document 1).
特許第4775930号Japanese Patent No. 4775930
　コントラストＡＦは，高精度にフォーカス・レンズを合焦位置に位置決めできるが，その位置決め範囲はフォーカス・レンズが合焦位置近傍にある位置決め許容範囲内にある場合に限られ，その位置決め許容範囲外にフォーカス・レンズがある場合には位置決めできない。これに対して，位相差ＡＦでは、合焦位置から大きく外れた位置にフォーカス・レンズがあっても、合焦位置への駆動を行える反面、フォーカス・レンズの合焦位置への位置決めはあまり正確ではない。引用文献１においては，このようなＡＦ方式の特徴を生かすことは考えられていない。 Contrast AF can position the focus lens at the in-focus position with high accuracy, but the positioning range is limited to when the focus lens is within the allowable positioning range near the in-focus position. Positioning cannot be performed when there is a focus lens. On the other hand, with phase difference AF, even if the focus lens is located far away from the in-focus position, it can be driven to the in-focus position, but the focus lens is not very accurately positioned at the in-focus position. is not. In Cited Document 1, it is not considered to make use of such features of the AF method.
　この発明は，コントラストＡＦ，位相差ＡＦの特徴を生かしてフォーカス・レンズを合焦位置に位置決めすることを目的とする。 An object of the present invention is to position the focus lens at the in-focus position by making use of the features of contrast AF and phase difference AF.
　この発明によるオート・フォーカス装置は，フォーカス・レンズを通って入射する光が瞳分割により二つに分けられて結像する二つの被写体像の瞳分割方向の位置ずれ量にもとづいてピントのずれ量を示す第１の合焦評価値信号を出力する第１の合焦評価値出力部，フォーカス・レンズを通って入射する光の光路において，光路長が互いに異なる位置に配置された第１の撮像素子および第２の撮像素子，第１の撮像素子の出力信号と第２の撮像素子の出力信号とにもとづいてピントのずれ量を示す第２の合焦評価値信号を出力する第２の合焦評価値出力部，フォーカス・レンズの位置が，被写体像が合焦する位置近傍のしきい値以上に被写体像が合焦する位置から離れている場合は第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいてフォーカス・レンズを移動し，フォーカス・レンズがしきい値位置よりも被写体像が合焦する位置に近い場合は第２の合焦評価値出力部から出力する第２の合焦評価値信号にもとづいてフォーカス・レンズを，被写体像が合焦する位置に位置決めするフォーカス・レンズ移動部，フォーカス・レンズ移動部によってフォーカス・レンズが位置決めされた位置が，被写体像が合焦するフォーカス・レンズの位置かどうかを，第１の合焦評価値出力部から出力した第１の合焦評価値信号にもとづいて判定する第１の位置判定部，ならびに第１の位置判定部によって，フォーカス・レンズ移動部によってフォーカス・レンズが位置決めされた位置が，被写体像が合焦するフォーカス・レンズの位置ではないと判定されたことに応じて，第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいてフォーカス・レンズを移動するようにフォーカス・レンズ移動部を制御する第１の移動制御部を備えていることを特徴とする。 The autofocus device according to the present invention is based on the amount of focus deviation in the pupil division direction of the two subject images formed by dividing the light incident through the focus lens into two by pupil division. A first in-focus evaluation value output unit for outputting a first in-focus evaluation value signal, and a first imaging in which optical path lengths are arranged at different positions in an optical path of light incident through a focus lens A second focus evaluation value signal indicating a focus shift amount based on the output signal of the element, the second image sensor, the output signal of the first image sensor, and the output signal of the second image sensor. When the position of the focus evaluation value output unit and the focus lens is far from the position where the subject image is in focus beyond the threshold value near the position where the subject image is in focus, the focus evaluation value output unit Output first focus evaluation value The focus lens is moved based on the signal, and the second focus evaluation output from the second focus evaluation value output unit when the focus lens is closer to the position where the subject image is focused than the threshold position. The focus lens is positioned at the position where the subject image is in focus based on the value signal, and the position where the focus lens is positioned by the focus lens movement unit is the focus The first position determination unit and the first position determination unit for determining whether or not the position of the lens is based on the first focus evaluation value signal output from the first focus evaluation value output unit. In response to determining that the position of the focus lens by the lens moving unit is not the focus lens position at which the subject image is in focus , And a first movement control unit for controlling the focus / lens moving unit to move the focus / lens based on the first focusing evaluation value signal output from the first focusing evaluation value output unit. It is characterized by being.
　この発明は，オート・フォーカス装置に適した動作制御方法も提供している。すなわち，この方法は，第１の合焦評価値出力部が，フォーカス・レンズを通って入射する光が瞳分割により二つに分けられて結像する二つの被写体像の瞳分割方向の位置ずれ量にもとづいてピントのずれ量を示す第１の合焦評価値信号を出力し，第２の合焦評価値出力部が，フォーカス・レンズを通って入射する光の光路において，光路長が互いに異なる位置に配置された第１の撮像素子および第２の撮像素子のそれぞれの出力信号とにもとづいてピントのずれ量を示す第２の合焦評価値信号を出力し，フォーカス・レンズ移動部が，フォーカス・レンズの位置が，被写体像が合焦する位置近傍のしきい値以上に被写体像が合焦する位置から離れている場合は第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいてフォーカス・レンズを移動し，フォーカス・レンズがしきい値位置よりも被写体像が合焦する位置に近い場合は第２の合焦評価値出力部から出力する第２の合焦評価値信号にもとづいてフォーカス・レンズを，被写体像が合焦する位置に位置決めし，位置判定部が，フォーカス・レンズ移動部によってフォーカス・レンズが位置決めされた位置が，被写体像が合焦するフォーカス・レンズの位置かどうかを，第１の合焦評価値出力部から出力した第１の合焦評価値信号にもとづいて判定し，移動制御部が，第１の位置判定部によって，フォーカス・レンズ移動部によってフォーカス・レンズが位置決めされた位置が，被写体像が合焦するフォーカス・レンズの位置ではないと判定されたことに応じて，第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいてフォーカス・レンズを移動するようにフォーカス・レンズ移動部を制御するものである。 The present invention also provides an operation control method suitable for an autofocus device. That is, in this method, the first focus evaluation value output unit shifts the position in the pupil division direction of two subject images formed by dividing the light incident through the focus lens into two by pupil division. A first focus evaluation value signal indicating the amount of focus shift based on the amount of light, and the second focus evaluation value output unit has optical path lengths in the optical paths of light incident through the focus lens. Based on the output signals of the first image sensor and the second image sensor arranged at different positions, a second focus evaluation value signal indicating a focus shift amount is output, and the focus / lens moving unit The first focus evaluation value output unit outputs the first focus evaluation value when the position of the focus lens is far from the position where the subject image is in focus beyond the threshold value near the position where the subject image is in focus. Based on the focus evaluation value signal of If the focus lens is moved and the focus lens is closer to the position where the subject image is in focus than the threshold value position, it is based on the second focus evaluation value signal output from the second focus evaluation value output unit. The focus lens is positioned at the position where the subject image is in focus, and the position where the focus lens is positioned by the focus lens moving unit is the position of the focus lens where the subject image is focused. Is determined based on the first focus evaluation value signal output from the first focus evaluation value output unit, and the movement control unit uses the first position determination unit to focus the focus / lens moving unit. In response to determining that the position where the lens is positioned is not the position of the focus lens at which the subject image is in focus, the first focus evaluation value output unit outputs the first focus output value. Based on the focus evaluation value signal is for controlling the focus lens moving unit to move the focus lens.
　この発明によると，フォーカス・レンズが，被写体像が合焦する位置近傍のしきい値位置となるまでは，精度は高く無いが比較的速くフォーカス・レンズを移動させることができる第１のＡＦセンサから出力される第１の合焦評価値信号にもとづいてフォーカス・レンズが移動させられる。フォーカス・レンズが，被写体像が合焦する位置近傍のしきい値位置となると，フォーカス・レンズの移動を速くできないが高精度に合焦位置に位置決めできる第２のＡＦセンサから出力される第２の合焦評価値信号にもとづいてフォーカス・レンズが移動させられ，合焦位置に位置決めされる。 According to the present invention, the first AF sensor that can move the focus lens relatively quickly is not high in accuracy until the focus lens reaches a threshold position near the position where the subject image is focused. The focus lens is moved on the basis of the first focus evaluation value signal output from. When the focus lens reaches a threshold position in the vicinity of the position where the subject image is in focus, the second AF sensor output from the second AF sensor that cannot be quickly moved but can be positioned at the focus position with high accuracy. The focus lens is moved based on the in-focus evaluation value signal and positioned at the in-focus position.
　第２のＡＦセンサから出力される第２の合焦評価値信号は，許容範囲外にフォーカス・レンズがある場合には，合焦位置に位置決めされていると判断されてしまうことがある。このために，撮像シーンが変化してフォーカス・レンズが第２のＡＦセンサから出力される第２の合焦評価値信号にもとづいてフォーカス・レンズの位置決めを続けているとフォーカス・レンズが許容範囲外となり，合焦位置に位置決めされていないにもかかわらず，合焦位置に位置決めされていると判断され，合焦できないことがある。このために，第２のＡＦセンサから出力される第２の合焦評価値信号にもとづいてフォーカス・レンズが移動させられ，合焦位置に位置決めされると，第１のＡＦセンサから出力する第１の合焦評価値信号にもとづいて，第２のＡＦセンサから出力される第２の合焦評価値信号にもとづいて位置決めされたフォーカス・レンズの位置が，被写体像が合焦する位置かどうかが判定され，そのような位置ではないと判定されると第１のＡＦセンサから出力する第１の合焦評価値信号にもとづいてフォーカス・レンズが移動させられる。これにより、シーン変化などにより，第２のＡＦセンサから出力される第２の合焦評価値信号にもとづいてフォーカス・レンズが位置決めされると，合焦位置に位置決めできなくなるような場合でも，合焦位置に位置決めできるようになる。 The second focus evaluation value signal output from the second AF sensor may be determined to be positioned at the focus position when the focus lens is outside the allowable range. For this reason, if the imaging lens changes and the focus lens continues to position the focus lens based on the second focus evaluation value signal output from the second AF sensor, the focus lens is within the allowable range. It may be determined that the lens is positioned at the in-focus position even though it is not positioned at the in-focus position, and the in-focus state may not be achieved. For this reason, when the focus lens is moved based on the second focus evaluation value signal output from the second AF sensor and positioned at the focus position, the first AF sensor output from the first AF sensor. Whether the position of the focus lens positioned based on the second focus evaluation value signal output from the second AF sensor based on the first focus evaluation value signal is a position where the subject image is in focus If it is determined that the position is not such a position, the focus lens is moved based on the first focus evaluation value signal output from the first AF sensor. As a result, even if the focus lens is positioned based on the second focus evaluation value signal output from the second AF sensor due to a scene change or the like, it cannot be positioned at the focus position. It becomes possible to position in the focal position.
　第１の移動制御部によるフォーカス・レンズ移動部の制御によりフォーカス・レンズが移動されたことに応じて，第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいてフォーカス・レンズを移動するようにフォーカス・レンズ移動部を制御する第２の移動制御部をさらに備えるようにしてもよい。また，フォーカス・レンズが，被写体像が合焦する位置に向けて移動してしきい値位置となったことに応じて第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて定められる被写体像が合焦するフォーカス・レンズの位置と第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいて定められる被写体像が合焦するフォーカス・レンズの位置とが一致するかどうかを判定する第２の位置判定部をさらに備えてもよい。その場合，フォーカス・レンズ移動部は，記第２の位置判定部によって一致すると判定されたことに応じて，第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいてフォーカス・レンズを，被写体像が合焦する位置に位置決めするものとなろう。 Based on the second focus evaluation value signal output from the second focus evaluation value output unit in response to the movement of the focus lens by the control of the focus / lens movement unit by the first movement control unit. A second movement control unit that controls the focus / lens moving unit to move the focus / lens may be further provided. In addition, the first focus evaluation output from the first focus evaluation value output unit in response to the focus lens moving toward the position where the subject image is focused and reaching the threshold position. The focus lens position where the subject image determined based on the value signal is in focus and the subject image determined based on the second focus evaluation value signal output from the second focus evaluation value output unit A second position determining unit that determines whether or not the position of the focus lens to be matched may be further included. In this case, the focus / lens moving unit outputs the second focus evaluation value signal output from the second focus evaluation value output unit in response to the determination that the second position determination unit matches. Basically, the focus lens will be positioned at the position where the subject image is in focus.
　フォーカス・レンズ移動部によりフォーカス・レンズが，被写体像が合焦する位置に位置決めされた後に，第１の合焦評価値出力部から出力される第１の合焦評価値信号または第２の合焦評価値出力部から出力される第２の合焦評価値信号が変化したことに応じて，第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいてフォーカス・レンズの位置が，しきい値位置よりも合焦位置から遠い位置となり，かつ第１の合焦評価値信号によって表されるフォーカス・レンズの移動方向および第２の合焦評価値信号によって表されるフォーカス・レンズの移動方向に一致しているかどうかを判定する第１の判定部，および第１の判定部によってフォーカス・レンズの位置が，しきい値位置よりも合焦位置から遠い位置となり，かつ第１の合焦評価値信号によって表されるフォーカス・レンズの移動方向および第２の合焦評価値信号によって表されるフォーカス・レンズの移動方向に一致していると判定されたことに応じて，第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいてフォーカス・レンズを移動するようにフォーカス・レ　ンズ移動部を制御する第３の移動制御部をさらに備えてもよい。 After the focus lens is positioned at a position where the subject image is in focus by the focus / lens moving unit, the first focus evaluation value signal or the second focus evaluation value signal output from the first focus evaluation value output unit. Focusing is performed based on the first focus evaluation value signal output from the first focus evaluation value output unit in response to a change in the second focus evaluation value signal output from the focus evaluation value output unit. The position of the lens is farther from the in-focus position than the threshold position, and is expressed by the focus lens moving direction and the second in-focus evaluation value signal represented by the first in-focus evaluation value signal. The first determination unit that determines whether or not the movement direction of the focus lens is coincident, and the position of the focus lens is farther from the in-focus position than the threshold position by the first determination unit. , In response to determining that the movement direction of the focus lens represented by the first focus evaluation value signal and the movement direction of the focus lens represented by the second focus evaluation value signal are the same. And a third movement control unit for controlling the focus lens moving unit to move the focus lens based on the first focusing evaluation value signal output from the first focusing evaluation value output unit. Further, it may be provided.
　フォーカス・レンズ移動部によりフォーカス・レンズが，被写体像が合焦する位置に位置決めされた後に，第１の合焦評価値出力部から出力される第１の合焦評価値信号または第２の合焦評価値出力部から出力される第２の合焦評価値信号が変化したことに応じて，第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいてフォーカス・レンズの位置が，しきい値位置よりも合焦位置に近い位置となり，かつ第１の合焦評価値信号によって表されるフォーカス・レンズの移動方向および第２の合焦評価値信号によって表されるフォーカス・レンズの移動方向に一致していないどうかを判定する第２の判定部，および第２の判定部によってフォーカス・レンズの位置が，しきい値位置よりも合焦位置から近い位置となり，かつ第１の合焦評価値信号によって表されるフォーカス・レンズの移動方向および第２の合焦評価値信号によって表されるフォーカス・レンズの移動方向に一致していないと判定されたことに応じて，第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいてフォーカス・レンズを移動するようにフォーカス・レンズ　移動部を制御する第４の移動制御部をさらに備えてもよい。 After the focus lens is positioned at a position where the subject image is in focus by the focus / lens moving unit, the first focus evaluation value signal or the second focus evaluation value signal output from the first focus evaluation value output unit. Focusing is performed based on the first focus evaluation value signal output from the first focus evaluation value output unit in response to a change in the second focus evaluation value signal output from the focus evaluation value output unit. The lens position is closer to the in-focus position than the threshold position, and is expressed by the focus lens moving direction and the second in-focus evaluation value signal represented by the first in-focus evaluation value signal. The position of the focus lens is closer to the in-focus position than the threshold value position by the second determination section that determines whether or not the movement direction of the focus lens is not matched, and the second determination section. , Or In response to determining that the movement direction of the focus lens represented by the first focus evaluation value signal and the movement direction of the focus lens represented by the second focus evaluation value signal do not match. And a fourth movement control unit for controlling the focus lens moving unit to move the focus lens based on the second focus evaluation value signal output from the second focus evaluation value output unit. May be.
撮像レンズ・ユニットの構成を示している。The structure of an imaging lens unit is shown. 光路長差ＡＦ用撮像素子と被写体像の結像位置との関係を示している。The relationship between the image sensor for optical path length difference AF and the imaging position of a subject image is shown. ＡＦ評価値とフォーカス・レンズ位置との関係を示している。The relationship between the AF evaluation value and the focus / lens position is shown. 位相差ＡＦ評価値とフォーカス・レンズ位置との関係を示している。The relationship between the phase difference AF evaluation value and the focus / lens position is shown. 差分ＡＦ評価値とフォーカス・レンズ位置との関係を示している。The relationship between the differential AF evaluation value and the focus / lens position is shown. 合焦処理手順を示すフローチャートである。It is a flowchart which shows a focusing process procedure. 合焦処理手順を示すフローチャートである。It is a flowchart which shows a focusing process procedure.
　図１は，この発明の実施例を示すもので，放送用などに利用される撮影レンズ・ユニット１とカメラ本体20の一部の光学的構成を示している。 FIG. 1 shows an embodiment of the present invention, and shows an optical configuration of a part of a photographing lens unit 1 and a camera body 20 used for broadcasting or the like.
　撮影レンズ・ユニット１は着脱自在にカメラ本体20に装着されている。 The taking lens unit 1 is detachably attached to the camera body 20.
　撮影レンズ・ユニット１には，撮影レンズ・ユニット１の光軸Ｏ１と共通の光軸をもつようにフォーカス・レンズ（フォーカス・レンズ群）２，ズーム・レンズ（ズーム・レンズ群）３，前側リレー・レンズ（前側リレー・レンズ群）５および後側リレー・レンズ（後側リレー・レンズ群）７が含まれている。ズーム・レンズ３と前側リレー・レンズ５との間には，撮影レンズ・ユニット１の光軸Ｏ１が中心を通るように絞り４が配置されている。また，前側リレー・レンズ５と後側リレー・レンズ７との間にはハーフ・ミラー６が配置されている。 The photographic lens unit 1 includes a focus lens (focus lens group) 2, a zoom lens (zoom lens group) 3, and a front relay so as to have an optical axis common to the optical axis O1 of the photographic lens unit 1 A lens (front relay / lens group) 5 and a rear relay / lens (rear relay / lens group) 7 are included. A diaphragm 4 is arranged between the zoom lens 3 and the front relay lens 5 so that the optical axis O1 of the photographing lens unit 1 passes through the center. A half mirror 6 is arranged between the front relay lens 5 and the rear relay lens 7.
　カメラ本体20には，撮影レンズ・ユニット１が装着されたときに撮影レンズ・ユニット１の光軸Ｏ１と共通の光軸をもつ色分解プリズム21が設けられている。この色分解プリズム21には，第１のプリズム22，第２のプリズム23および第３のプリズム24が含まれており，入射した光が赤色成分，緑色成分および青色成分に分解される。第１のプリズム22の出射面に対向する位置，第２のプリズム23の出射面に対向する位置および第３のプリズム24の出射面に対向する位置に，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27がそれぞれ配置されている。 The camera body 20 is provided with a color separation prism 21 having an optical axis common to the optical axis O1 of the photographing lens unit 1 when the photographing lens unit 1 is mounted. The color separation prism 21 includes a first prism 22, a second prism 23, and a third prism 24, and incident light is separated into a red component, a green component, and a blue component. The first imaging CCD 25, the second imaging CCD 25, the second imaging prism 25, the second prism 23, the third prism 24, the second prism 23, the second prism 23, and the third prism 24, respectively. An imaging CCD 26 and a third imaging CCD 27 are arranged.
　さらに，撮影レンズ・ユニット１には，ハーフ・ミラー６の中心で反射した一部の光を光軸［ＡＦ（オート・フォーカス）用光軸］Ｏ２とするＡＦ用リレー・レンズ（ＡＦ用リレー・レンズ群）８が設けられている。ＡＦ用リレー・レンズ８の後段にはハーフ・ミラー40（反射プリズムでもよい）が設けられている。また，ハーフ・ミラー40の後段には全反射ミラー９が設けられている。 Further, the photographing lens unit 1 includes an AF relay lens (AF relay lens) that uses a part of the light reflected at the center of the half mirror 6 as an optical axis [optical axis for AF (auto focus)] O2. Lens group) 8 is provided. A half mirror 40 (which may be a reflecting prism) is provided downstream of the AF relay lens 8. A total reflection mirror 9 is provided after the half mirror 40.
　全反射ミラー９の全反射方向には光路長差ＡＦセンサ55が設けられている。光路長差ＡＦセンサ55には第１のプリズム11と第２のプリズム12とから構成される分割プリズム10が含まれている。第１のプリズム11の出射面および第２のプリズム12の出射面には第１のＡＦ用ＣＣＤ13および第２のＡＦ用ＣＣＤ14がそれぞれ設けられている。 An optical path length difference AF sensor 55 is provided in the total reflection direction of the total reflection mirror 9. The optical path length difference AF sensor 55 includes a split prism 10 composed of a first prism 11 and a second prism 12. A first AF CCD 13 and a second AF CCD 14 are provided on the exit surface of the first prism 11 and the exit surface of the second prism 12, respectively.
　撮影レンズ・ユニット１に入射した光線束は，フォーカス・レンズ２，ズーム・レンズ３，絞り４，前側リレー・レンズ５，ハーフ・ミラー６および後側リレー・レンズ７を透過してカメラ本体20に導かれる。カメラ本体20に含まれる光分解プリズム21において，光線束は，赤色光成分，緑色光成分および青色光成分にそれぞれ分解され，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27のそれぞれにおいて被写体像が結像する。第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27のそれぞれから赤色光成分，緑色光成分および青色光成分の被写体像を表わす映像信号が出力されることとなる。 The light beam incident on the photographic lens unit 1 passes through the focus lens 2, zoom lens 3, aperture 4, front relay lens 5, half mirror 6 and rear relay lens 7, and enters the camera body 20. Led. In the light decomposing prism 21 included in the camera body 20, the light beam is decomposed into a red light component, a green light component, and a blue light component, respectively, and the first image pickup CCD 25, the second image pickup CCD 26, and the third image pickup device. A subject image is formed on each of the CCDs 27 for use. Video signals representing subject images of the red light component, the green light component, and the blue light component are output from the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27, respectively.
　撮影レンズ・ユニット１に入射した光線束は，ハーフ・ミラー６において一部が反射する。ハーフ・ミラー６において反射した光線束は，ＡＦ用リレー・レンズ８を透過し，ハーフ・ミラー40に導かれる。 The light beam incident on the taking lens unit 1 is partially reflected by the half mirror 6. The light beam reflected by the half mirror 6 passes through the AF relay lens 8 and is guided to the half mirror 40.
　ハーフ・ミラー40に入射した光の一部は反射して位相差ＡＦセンサ45に含まれる位相差センサ41に入射する。 A part of the light incident on the half mirror 40 is reflected and incident on the phase difference sensor 41 included in the phase difference AF sensor 45.
　位相差センサ41には集光レンズ，セパレータ・レンズおよび撮像素子（いずれも図示略）が含まれている。位相差センサ41に入射した光が集光レンズによって集光され，かつセパレータ・レンズによって二つに分けられる。二つに分けられた光が撮像素子上で二つの画像として結像する。二つの画像の間隔からフォーカス・レンズ２が合焦するようにフォーカス・レンズ２を制御できる。位相差センサ41からは，二つの画像を表わす映像信号が出力され，評価値算出回路42において，撮像によって得られた被写体像の合焦の程度を表わす位相差ＡＦ評価値が生成される。位相差ＡＦ評価値を表わす信号（第１の合焦評価値信号）は増幅回路43を介してセレクタ33に入力する。 The phase difference sensor 41 includes a condenser lens, a separator lens, and an image sensor (all not shown). The light incident on the phase difference sensor 41 is condensed by the condenser lens and divided into two by the separator lens. The light divided into two forms an image on the image sensor as two images. The focus lens 2 can be controlled so that the focus lens 2 is focused from the interval between the two images. The phase difference sensor 41 outputs video signals representing two images, and the evaluation value calculation circuit 42 generates a phase difference AF evaluation value representing the degree of focusing of the subject image obtained by imaging. A signal representing the phase difference AF evaluation value (first focus evaluation value signal) is input to the selector 33 via the amplifier circuit 43.
　ハーフ・ミラー40を透過した光は，全反射ミラー９において全反射する。全反射ミラー９において全反射した光線束は光路長差ＡＦセンサ55に含まれる分割プリズム10に入射し，一部が第１の光路長差ＡＦ用ＣＣＤ13に入射し，残りが第２の光路長差ＡＦ用ＣＣＤ14に入射する。第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14のそれぞれからＡＦ用の信号が出力することとなる。 The light transmitted through the half mirror 40 is totally reflected by the total reflection mirror 9. The light beam totally reflected by the total reflection mirror 9 is incident on the splitting prism 10 included in the optical path length difference AF sensor 55, a part is incident on the first optical path length difference AF CCD 13, and the rest is the second optical path length. The light enters the CCD 14 for difference AF. An AF signal is output from each of the first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14.
　第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14からそれぞれ出力した信号は評価値算出回路51および52にそれぞれに入力し，フォーカス・レンズ２の合焦の程度を表わすそれぞれの評価値が算出される。評価値算出回路51および52のそれぞれにおいて算出された評価値を表わす信号は，減算回路53に与えられる。評価値算出回路51において算出された評価値を表わす信号から，評価値算出回路52において算出された評価値を表わす信号が，減算回路53において減算され，差分ＡＦ評価値が得られる。差分ＡＦ評価値を表わす信号（第２の合焦評価値信号）が増幅回路54において増幅されてセレクタ33に与えられる。 Signals output from the first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14 are input to the evaluation value calculation circuits 51 and 52, respectively, and indicate the degree of focusing of the focus lens 2. Is evaluated. Signals representing the evaluation values calculated in the evaluation value calculation circuits 51 and 52 are supplied to the subtraction circuit 53. The signal representing the evaluation value calculated in the evaluation value calculating circuit 52 is subtracted in the subtracting circuit 53 from the signal representing the evaluation value calculated in the evaluation value calculating circuit 51 to obtain a differential AF evaluation value. A signal representing the differential AF evaluation value (second focus evaluation value signal) is amplified by the amplifier circuit 54 and is supplied to the selector 33.
　増幅回路43から出力した位相差ＡＦ評価値信号および増幅回路54から出力した差分ＡＦ評価値信号は，切替制御回路31にも入力する。入力した位相差ＡＦ評価値信号および差分ＡＦ評価値信号にもとづいてセレクタ33が制御され，増幅回路43から出力される位相差ＡＦ評価値信号または増幅回路54から出力される差分ＡＦ評価値信号のいずれかがゲイン制御増幅回路34に与えられる。ゲイン制御増幅回路34において，入力した信号が増幅されて，回転方向および回転速度を表わす制御信号としてフォーカス・モータ35に与えられる。フォーカス・モータ35によってフォーカス・レンズ２が移動させられる。 The phase difference AF evaluation value signal output from the amplifier circuit 43 and the difference AF evaluation value signal output from the amplifier circuit 54 are also input to the switching control circuit 31. The selector 33 is controlled based on the input phase difference AF evaluation value signal and the difference AF evaluation value signal, and the phase difference AF evaluation value signal output from the amplifier circuit 43 or the difference AF evaluation value signal output from the amplifier circuit 54 Either one is supplied to the gain control amplification circuit 34. In the gain control amplification circuit 34, the input signal is amplified and applied to the focus motor 35 as a control signal representing the rotation direction and the rotation speed. The focus lens 2 is moved by the focus motor 35.
　図２は，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27ならびに第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14の光学的距離の関係を示している。 FIG. 2 shows the relationship between the optical distances of the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF CCD 14. Is shown.
　第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27ならびに第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14に光を入射させるための光学系がレンズ30によって表わされている。 An optical system for causing light to enter the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF CCD 14 is provided. Represented by lens 30.
　第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27に入射するまでの光学的距離は，いずれも等しい。これに対して，第１の光路長差ＡＦ用ＣＣＤ13に入射するまでの光学的距離は，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27から所定の距離だけ前に配置された場合に等しく，第２の光路長差ＡＦ用ＣＣＤ14に入射するまでの光学的距離は，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27から所定の距離だけ後に配置された場合に等しくなるように，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27ならびに第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14の位置関係（光学的に前後等間隔の位置）が規定されている。仮に同一光軸上に第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27ならびに第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14が配置されると，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27の前後等間隔の位置に第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14が配置されていることと等価となる。 The optical distances until the light enters the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27 are all equal. On the other hand, the optical distance until the light enters the first optical path length difference AF CCD 13 is a predetermined distance from the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27. The optical distance until the light enters the second optical path length difference AF CCD 14 is equal to a predetermined distance from the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27. The first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference so as to be equal when they are arranged after a distance. The positional relationship of the AF CCD 14 (optically equidistantly spaced positions) is defined. Temporarily, the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF CCD 14 are arranged on the same optical axis. The first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14 are arranged at equally spaced positions before and after the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27. It is equivalent to what is done.
　図３は，ＡＦ評価値とフォーカス・レンズ２の位置との関係を示している。 FIG. 3 shows the relationship between the AF evaluation value and the position of the focus lens 2.
　第１の光路長差ＡＦ用ＣＣＤ13から出力される信号にもとづいて評価値算出回路51において算出された評価値信号からグラフＧ51が得られ，第２の光路長差ＡＦ用ＣＣＤ14から出力される信号にもとづいて評価値算出回路52において算出された評価値信号からグラフＧ52が得られる。 A graph G51 is obtained from the evaluation value signal calculated by the evaluation value calculation circuit 51 based on the signal output from the first optical path length difference AF CCD 13, and the signal output from the second optical path length difference AF CCD 14 is obtained. A graph G52 is obtained from the evaluation value signal calculated by the evaluation value calculation circuit 52 based on the above.
　上述したように，仮に同一光軸上に第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27ならびに第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14が配置されると，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27の前後等間隔の位置に第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14が配置されていることと等価であるから，第１の光路長差ＡＦ用ＣＣＤ13および第２の光路長差ＡＦ用ＣＣＤ14のそれぞれの信号から得られたグラフＧ51およびＧ52との交点であるフォーカス・レンズ位置Ｐ０が，第１の撮像用ＣＣＤ25，第２の撮像用ＣＣＤ26および第３の撮像用ＣＣＤ27に被写体像が合焦するフォーカス・レンズ２の位置となる。 As described above, the first imaging CCD 25, the second imaging CCD 26, the third imaging CCD 27, the first optical path length difference AF CCD 13, and the second optical path length difference AF are assumed to be on the same optical axis. When the CCD 14 is arranged, the first optical path length difference AF CCD 13 and the second optical path length difference are arranged at equal intervals before and after the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27. Since this is equivalent to the arrangement of the AF CCD 14, at the intersections of the graphs G51 and G52 obtained from the signals of the first optical path length difference AF CCD 13 and the second optical path length difference AF CCD 14, respectively. A certain focus lens position P0 is the position of the focus lens 2 where the subject image is focused on the first imaging CCD 25, the second imaging CCD 26, and the third imaging CCD 27.
　図４は，位相差ＡＦ評価値とフォーカス・レンズ２の位置との関係を示している。横軸がフォーカス・レンズ２の位置を示し，縦軸が位相差ＡＦ評価値を示している。 FIG. 4 shows the relationship between the phase difference AF evaluation value and the position of the focus lens 2. The horizontal axis indicates the position of the focus lens 2, and the vertical axis indicates the phase difference AF evaluation value.
　評価値算出回路42において位相差ＡＦ評価値が算出されると，算出された位相差ＡＦ評価値とグラフＧ０との関係からフォーカス・レンズ２の位置が分る。たとえば，評価値算出回路42において算出された位相差ＡＦ評価値がＤ21またはＤ22であれば，フォーカス・レンズ２の位置は，Ｐ11またはＰ12である。また，位相差ＡＦ評価値が０であれば，フォーカス・レンズ２の位置Ｐ０は被写体像が合焦する合焦位置とほぼ等しい。位相差ＡＦ評価値が０となるようにフォーカス・レンズ２が移動させられることにより被写体像が合焦することとなる。 When the phase difference AF evaluation value is calculated in the evaluation value calculation circuit 42, the position of the focus lens 2 is determined from the relationship between the calculated phase difference AF evaluation value and the graph G0. For example, if the phase difference AF evaluation value calculated by the evaluation value calculation circuit 42 is D21 or D22, the position of the focus lens 2 is P11 or P12. If the phase difference AF evaluation value is 0, the position P0 of the focus lens 2 is substantially equal to the in-focus position at which the subject image is in focus. By moving the focus lens 2 so that the phase difference AF evaluation value becomes 0, the subject image is brought into focus.
　ＡＦ評価値とフォーカス・レンズ２との関係はステップ状のグラフ０となり，位相差ＡＦ評価値が０のときに合焦位置Ｐ０は完全には対応しないことがある。 The relationship between the AF evaluation value and the focus lens 2 is a stepped graph 0, and when the phase difference AF evaluation value is 0, the focus position P0 may not correspond completely.
　また，この実施例では，合焦位置Ｐ０近傍のしきい値位置Ｐ１およびＰ２が規定されており，フォーカス・レンズ２が，これらのしきい値位置Ｐ１およびＰ２よりも外側（合焦位置Ｐ０から遠くなる位置）にフォーカス・レンズ２がある場合には図４に示すように位相差評価値が利用される（位相差ＡＦ使用範囲）。これに対して，フォーカス・レンズ２がしきい値位置Ｐ１からＰ２の間にあるときには図５に示す差分ＡＦ評価値を利用してフォーカス・レンズ２が位置決めされる（光路長差ＡＦ使用範囲）。 In this embodiment, threshold positions P1 and P2 in the vicinity of the focus position P0 are defined, and the focus lens 2 is located outside these threshold positions P1 and P2 (from the focus position P0). When the focus lens 2 is located at a far position), the phase difference evaluation value is used (phase difference AF use range) as shown in FIG. On the other hand, when the focus lens 2 is between the threshold positions P1 and P2, the focus lens 2 is positioned using the differential AF evaluation value shown in FIG. 5 (optical path length difference AF use range). .
　図５は，減算回路53から出力される差分ＡＦ評価値信号とフォーカス・レンズ２の位置と関係を示すグラフＧ53である。横軸がフォーカス・レンズ位置であり，縦軸が差分ＡＦ評価値である。 FIG. 5 is a graph G53 showing the relationship between the differential AF evaluation value signal output from the subtraction circuit 53 and the position of the focus lens 2. The horizontal axis is the focus lens position, and the vertical axis is the differential AF evaluation value.
　差分ＡＦ評価値の正のピーク値Ｄ11と負のピーク値Ｄ12との間では，差分ＡＦ評価値とフォーカス・レンズ２の位置関係は一対一に対応する。差分ＡＦ評価値が分れば，正のピーク値Ｄ11に対応するフォーカス・レンズ２の位置Ｐ11と負のピーク値Ｄ12に対応するフォーカス・レンズ２の位置Ｐ12との間におけるフォーカス・レンズ２の位置も分る。差分ＡＦ評価値が０となるフォーカス・レンズ２の位置が合焦位置である。 Between the positive peak value D11 and the negative peak value D12 of the differential AF evaluation value, the positional relationship between the differential AF evaluation value and the focus lens 2 corresponds one to one. If the differential AF evaluation value is known, the position of the focus lens 2 between the position P11 of the focus lens 2 corresponding to the positive peak value D11 and the position P12 of the focus lens 2 corresponding to the negative peak value D12. I understand. The position of the focus lens 2 at which the differential AF evaluation value is 0 is the in-focus position.
　差分ＡＦ評価値は，図３に示すようにグラフＧ51とＧ52との差分を示しており，正のピーク値Ｄ11で示されるフォーカス・レンズ２の位置Ｐ11と負のピーク値Ｄ12で示されるフォーカス・レンズ２の位置Ｐ12との間にフォーカス・レンズ２が無ければ，フォーカス・レンズ２を合焦位置Ｐ０に位置決めできない。その位置Ｐ11と位置Ｐ12との間を光路長差ＡＦセンサ55にもとづく光路長差ＡＦ可能範囲と呼ぶこととする。また，この実施例では，上述のように光路長差ＡＦ可能範囲内であって，合焦位置Ｐ０近傍の第１のしきい値位置Ｐ１と第２のしきい値位置Ｐ２との間の範囲（位相差ＡＦ使用範囲）に入るまでは位相差センサ45から得られる位相差ＡＦ評価値を利用してフォーカス・レンズ２が位置決めされるが，位相差ＡＦ使用範囲にフォーカス・レンズ２が入ると光路長差ＡＦセンサ55から得られる差分ＡＦ評価値を利用してフォーカス・レンズ２が位置決めされる。位相差ＡＦ範囲外にフォーカス・レンズ２があるときには，位相差センサ45から得られる位相差ＡＦ評価値を利用してフォーカス・レンズ２を移動するとフォーカス・レンズ２を速く移動させることができるのに対して，光路長差ＡＦセンサ55から得られる差分ＡＦ評価値を利用してフォーカス・レンズ２を移動した方がフォーカス・レンズ２を合焦位置Ｐ０に正確に位置決めできるからである。 As shown in FIG. 3, the difference AF evaluation value indicates the difference between the graphs G51 and G52, and the focus lens 2 position P11 indicated by the positive peak value D11 and the focus peak indicated by the negative peak value D12. If there is no focus lens 2 between the lens 2 and the position P12, the focus lens 2 cannot be positioned at the focus position P0. The distance between the position P11 and the position P12 is called an optical path length difference AF possible range based on the optical path length difference AF sensor 55. Further, in this embodiment, as described above, the range is within the optical path length difference AF possible range and between the first threshold value position P1 and the second threshold value position P2 near the in-focus position P0. The focus lens 2 is positioned using the phase difference AF evaluation value obtained from the phase difference sensor 45 until the phase difference AF usage range is entered, but when the focus lens 2 enters the phase difference AF usage range. The focus lens 2 is positioned using the differential AF evaluation value obtained from the optical path length difference AF sensor 55. When the focus lens 2 is outside the phase difference AF range, the focus lens 2 can be moved quickly by moving the focus lens 2 using the phase difference AF evaluation value obtained from the phase difference sensor 45. On the other hand, if the focus lens 2 is moved using the differential AF evaluation value obtained from the optical path length difference AF sensor 55, the focus lens 2 can be accurately positioned at the in-focus position P0.
　図６および図７は，合焦処理手順を示すフローチャートである。 6 and 7 are flowcharts showing the focusing processing procedure.
　位相差ＡＦセンサ45および光路長差ＡＦセンサ55の両方のセンサが駆動され，位相差ＡＦにもとづいてフォーカス・レンズ２の合焦位置からの位置ずれ量を示す位相差ＡＦ評価値および光路長差ＡＦにもとづく差分ＡＦ評価値が算出される（ステップ61）。 Both the phase difference AF sensor 45 and the optical path length difference AF sensor 55 are driven, and based on the phase difference AF, the phase difference AF evaluation value and the optical path length difference indicating the amount of displacement from the focus position of the focus lens 2. A differential AF evaluation value based on the AF is calculated (step 61).
　まず，位相差ＡＦセンサ45から得られる位相差ＡＦ評価値信号を利用して，フォーカス・レンズ２が合焦位置Ｐ０に近づくようにセレクタ34が切り替えられる（ステップ62）。位相差ＡＦ評価値信号を利用する場合には，フォーカス・レンズ２を速く移動させることができるので合焦までの時間を短縮できる。フォーカス・レンズ２が図５に示すようにしきい値位置Ｐ１またはＰ２を越えて光路長差ＡＦ使用範囲内に入るまで，位相差ＡＦセンサ45から得られる位相差ＡＦ評価値信号を利用してフォーカス・レンズ２が移動させられる（ステップ63でＮＯ）。 First, using the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45, the selector 34 is switched so that the focus lens 2 approaches the in-focus position P0 (step 62). When the phase difference AF evaluation value signal is used, since the focus lens 2 can be moved quickly, the time until focusing can be shortened. Focusing is performed using the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45 until the focus lens 2 enters the optical path length difference AF use range beyond the threshold position P1 or P2 as shown in FIG. The lens 2 is moved (NO in step 63).
　フォーカス・レンズ２が光路長差ＡＦ使用範囲内に入ると（ステップ63でＹＥＳ），位相差ＡＦセンサ45から得られた位相差ＡＦ評価値信号にもとづいて決定されるフォーカス・レンズ２の位置と光路長差ＡＦセンサ55から得られた差分ＡＦ評価値信号にもとづいて決定されるフォーカス・レンズ２の位置とがほぼ同じかどうかが確認される（ステップ64）。ほぼ同じでなければ（ステップ64でＮＯ），何らかのエラーが生じたと考えられるので所定のエラー処理が行われる。もっとも，位相差ＡＦセンサ45から得られる位相差ＡＦ評価値信号を利用してフォーカス・レンズ２を合焦位置Ｐ０に移動するようにしてもよい。 When the focus lens 2 enters the optical path length difference AF use range (YES in step 63), the position of the focus lens 2 determined based on the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45 It is confirmed whether or not the position of the focus lens 2 determined based on the differential AF evaluation value signal obtained from the optical path length difference AF sensor 55 is substantially the same (step 64). If they are not substantially the same (NO in step 64), it is considered that some kind of error has occurred, and a predetermined error process is performed. However, the focus lens 2 may be moved to the in-focus position P0 using the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45.
　ほぼ同じと考えられると（ステップ64でＹＥＳ），フォーカス・レンズ２を正確に合焦位置Ｐ０に位置決めするために光路長差ＡＦセンサ55から得られた差分ＡＦ評価値信号にもとづいてフォーカス・レンズ２が移動させられる（ステップ65）。差分ＡＦ評価値信号にもとづいてフォーカス・レンズ２が合焦位置Ｐ０に位置決めされると（ステップ66でＹＥＳ），その合焦位置が正しい位置かどうかが位相差センサ45から得られる位相差ＡＦ評価値信号にもとづいて判定される（ステップ67）。合焦位置が正しくないと判定されると（ステップ68でＮＯ），撮像シーン変化などにより光路長差ＡＦセンサ55からえられる差分ＡＦ評価値信号を用いてフォーカス・レンズ２の位置決めが可能なフォーカス位置決め許容範囲外にフォーカス・レンズ２が動いてしまったものと考えられる。このために，再び位相差ＡＦセンサ45から得られる位相差ＡＦ評価値信号を用いてフォーカス・レンズ２が移動させられる（ステップ62）。 If it is considered that they are substantially the same (YES in step 64), the focus lens is based on the differential AF evaluation value signal obtained from the optical path length difference AF sensor 55 in order to accurately position the focus lens 2 at the in-focus position P0. 2 is moved (step 65). When the focus lens 2 is positioned at the focus position P0 based on the differential AF evaluation value signal (YES in step 66), the phase difference AF evaluation obtained from the phase difference sensor 45 as to whether or not the focus position is correct is obtained. A determination is made based on the value signal (step 67). If it is determined that the in-focus position is not correct (NO in step 68), the focus / lens 2 can be positioned using the differential AF evaluation value signal obtained from the optical path length difference AF sensor 55 due to a change in the imaging scene or the like. It is considered that the focus lens 2 has moved outside the positioning allowable range. For this purpose, the focus lens 2 is moved again using the phase difference AF evaluation value signal obtained from the phase difference AF sensor 45 (step 62).
　合焦位置が正しいと判定されると（ステップ68でＹＥＳ），位相差ＡＦ評価値信号の値または差分ＡＦ評価値信号の値が，ある程度変化したかどうか（フォーカス・レンズ２の位置が光路長差ＡＦ使用範囲外となったかどうか）が確認される（ステップ69）。位相差ＡＦ評価値信号または差分ＡＦ評価値信号の値がある程度変化すると（ステップ69でＹＥＳ），フォーカス・レンズ２が光路長差ＡＦ可能範囲内にある場合に位相差ＡＦ評価値信号から分かるフォーカス・レンズ２の移動方向と光路長差ＡＦ評価値信号から分かるフォーカス・レンズ２の移動方向が同じかどうかが確認される（ステップ70）。同じであれば（ステップ70でＹＥＳ），差分ＡＦ評価値信号を用いてフォーカス・レンズ２を移動させるよりも位相差ＡＦ評価値信号を用いてフォーカス・レンズ２を移動させた方が速く合焦制御できるので，位相差ＡＦ評価値信号を用いて再度フォーカス・レンズが移動させられる（ステップ62）。 If it is determined that the in-focus position is correct (YES in step 68), whether the value of the phase difference AF evaluation value signal or the value of the difference AF evaluation value signal has changed to some extent (the position of the focus lens 2 is the optical path length). It is confirmed whether or not the difference AF is out of use range (step 69). When the value of the phase difference AF evaluation value signal or the difference AF evaluation value signal changes to some extent (YES in step 69), the focus that can be recognized from the phase difference AF evaluation value signal when the focus lens 2 is within the optical path length difference AF possible range It is confirmed whether or not the moving direction of the lens 2 and the moving direction of the focus lens 2 known from the optical path length difference AF evaluation value signal are the same (step 70). If they are the same (YES in step 70), the focus lens 2 is moved using the phase difference AF evaluation value signal faster than the focus lens 2 is moved using the difference AF evaluation value signal. Since control is possible, the focus lens is moved again using the phase difference AF evaluation value signal (step 62).
　位相差ＡＦ評価値信号から分かるフォーカス・レンズ２の移動方向と光路長差ＡＦ評価値信号から分かるフォーカス・レンズ２の移動方向が同じでなければ（ステップ70でＮＯ），フォーカス・レンズ２が光路長差ＡＦ可能範囲外かどうかが確認される（ステップ71）。フォーカス・レンズ２が光路長差ＡＦ可能範囲外であると（ステップ71でＹＥＳ），差分ＡＦ評価値信号を用いてフォーカス・レンズ２を位置決めすることができないので位相差ＡＦ評価値信号を用いてフォーカス・レンズ２が移動させられる（ステップ62）。フォーカス・レンズ２が光路長差ＡＦのフォーカス位置決め範囲内であると（ステップ71でＮＯ），光路長差ＡＦセンサ55にもとづく合焦制御を位相差ＡＦセンサ45にもとづく合焦制御よりも信頼性が高いと見なして，そのまま光路長差ＡＦセンサ55にもとづく合焦制御が続けられる。 If the movement direction of the focus lens 2 known from the phase difference AF evaluation value signal and the movement direction of the focus lens 2 known from the optical path length difference AF evaluation value signal are not the same (NO in step 70), the focus lens 2 is in the optical path. It is confirmed whether or not the long difference AF is possible (step 71). If the focus lens 2 is out of the optical path length difference AF possible range (YES in step 71), the focus lens 2 cannot be positioned using the differential AF evaluation value signal, so the phase difference AF evaluation value signal is used. The focus lens 2 is moved (step 62). When the focus lens 2 is within the focus positioning range of the optical path length difference AF (NO in step 71), the focus control based on the optical path length difference AF sensor 55 is more reliable than the focus control based on the phase difference AF sensor 45. Therefore, focusing control based on the optical path length difference AF sensor 55 is continued as it is.
13，14　光路長差ＡＦ用撮像素子
30　制御装置
31　切替制御回路
33　セレクタ
34　ゲイン制御増幅回路
41　位相差センサ
42，51，52　評価値算出回路
45　位相差ＡＦセンサ
55　光路長差ＡＦセンサ 13, 14 Image sensor for optical path length difference AF
30 Control unit
31 Switching control circuit
33 Selector
34 Gain control amplifier circuit
41 Phase difference sensor
42, 51, 52 Evaluation value calculation circuit
45 Phase difference AF sensor
55 Optical path length difference AF sensor

Claims (6)

  1. 　フォーカス・レンズを通って入射する光が瞳分割により二つに分けられて結像する二つの被写体像の瞳分割方向の位置ずれ量にもとづいてピントのずれ量を示す第１の合焦評価値信号を出力する第１の合焦評価値出力部，
    　前記フォーカス・レンズを通って入射する光の光路において，光路長が互いに異なる位置に配置された第１の撮像素子および第２の撮像素子，
    　前記第１の撮像素子の出力信号と前記第２の撮像素子の出力信号とにもとづいてピントのずれ量を示す第２の合焦評価値信号を出力する第２の合焦評価値出力部，
    　前記フォーカス・レンズの位置が，被写体像が合焦する位置近傍のしきい値以上に被写体像が合焦する位置から離れている場合は前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて前記フォーカス・レンズを移動し，前記フォーカス・レンズが前記しきい値位置よりも被写体像が合焦する位置に近い場合は前記第２の合焦評価値出力部から出力する第２の合焦評価値信号にもとづいて前記フォーカス・レンズを，被写体像が合焦する位置に位置決めするフォーカス・レンズ移動部，
    　前記フォーカス・レンズ移動部によって前記フォーカス・レンズが位置決めされた位置が，被写体像が合焦する前記フォーカス・レンズの位置かどうかを，前記第１の合焦評価値出力部から出力した第１の合焦評価値信号にもとづいて判定する第１の位置判定部，ならびに
    　前記第１の位置判定部によって，前記フォーカス・レンズ移動部によって前記フォーカス・レンズが位置決めされた位置が，被写体像が合焦する前記フォーカス・レンズの位置ではないと判定されたことに応じて，前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて前記フォーカス・レンズを移動するように前記フォーカス・レンズ移動部を制御する第１の移動制御部，
    　を備えたオート・フォーカス装置。     A first focus evaluation value indicating the amount of focus deviation based on the amount of positional deviation in the pupil division direction of two subject images formed by dividing the light incident through the focus lens into two by pupil division. A first focus evaluation value output unit for outputting a signal;
    A first imaging device and a second imaging device arranged in positions where the optical path lengths are different from each other in an optical path of light incident through the focus lens;
    A second focus evaluation value output unit for outputting a second focus evaluation value signal indicating a focus shift amount based on the output signal of the first image sensor and the output signal of the second image sensor;
    When the position of the focus lens is far from the position where the subject image is in focus beyond the threshold value near the position where the subject image is in focus, the first focus evaluation value output unit outputs The focus lens is moved based on the focus evaluation value signal of 1, and when the focus lens is closer to the position where the subject image is focused than the threshold value position, the second focus evaluation value is output. A focus / lens moving unit for positioning the focus lens at a position where the subject image is in focus based on a second focus evaluation value signal output from the unit;
    The first focus evaluation value output unit outputs from the first focus evaluation value output unit whether the position where the focus lens is positioned by the focus lens moving unit is the position of the focus lens where the subject image is focused. A first position determination unit that is determined based on a focus evaluation value signal, and a position at which the focus lens is positioned by the focus lens moving unit by the first position determination unit is in focus on the subject image. The focus lens is moved based on the first focus evaluation value signal output from the first focus evaluation value output unit when it is determined that the position is not the position of the focus lens. A first movement control unit for controlling the focus / lens movement unit,
    Auto focus device with
  2. 　前記第１の移動制御部による前記フォーカス・レンズ移動部の制御により前記フォーカス・レンズが移動されたことに応じて，前記第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいて前記フォーカス・レンズを移動するように前記フォーカス・レンズ移動部を制御する第２の移動制御部，
    　をさらに備えた請求項１に記載のオート・フォーカス装置。     The second focus evaluation output from the second focus evaluation value output unit in response to the focus lens being moved by the control of the focus lens moving unit by the first movement control unit. A second movement control unit for controlling the focus lens moving unit to move the focus lens based on a value signal;
    The autofocus device according to claim 1, further comprising:
  3. 　前記フォーカス・レンズが，被写体像が合焦する位置に向けて移動して前記しきい値位置となったことに応じて前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて定められる被写体像が合焦する前記フォーカス・レンズの位置と前記第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいて定められる被写体像が合焦する前記フォーカス・レンズの位置とが一致するかどうかを判定する第２の位置判定部をさらに備え，
    　前記フォーカス・レンズ移動部は，
    　前記第２の位置判定部によって一致すると判定されたことに応じて，前記第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいて前記フォーカス・レンズを，被写体像が合焦する位置に位置決めするものである，
    　請求項１または２に記載のオート・フォーカス装置。     The first focus output from the first focus evaluation value output unit in response to the focus lens moving toward the position where the subject image is focused and reaching the threshold position The subject image determined based on the position of the focus lens at which the subject image determined based on the evaluation value signal is focused and the second focus evaluation value signal output from the second focus evaluation value output unit A second position determination unit that determines whether or not the position of the focus lens that is in focus is the same;
    The focus lens moving unit is
    When the second position determination unit determines that they match, the focus lens is moved to the subject based on the second focus evaluation value signal output from the second focus evaluation value output unit. It is positioned at the position where the image is focused
    The autofocus device according to claim 1 or 2.
  4. 　前記フォーカス・レンズ移動部により前記フォーカス・レンズが，被写体像が合焦する位置に位置決めされた後に，前記第１の合焦評価値出力部から出力される第１の合焦評価値信号または前記第２の合焦評価値出力部から出力される第２の合焦評価値信号が変化したことに応じて，前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて前記フォーカス・レンズの位置が，前記しきい値位置よりも合焦位置から遠い位置となり，かつ前記第１の合焦評価値信号によって表される前記フォーカス・レンズの移動方向および前記第２の合焦評価値信号によって表される前記フォーカス・レンズの移動方向に一致しているかどうかを判定する第１の判定部，および
    　前記第１の判定部によって前記フォーカス・レンズの位置が，前記しきい値位置よりも合焦位置から遠い位置となり，かつ前記第１の合焦評価値信号によって表される前記フォーカス・レンズの移動方向および前記第２の合焦評価値信号によって表される前記フォーカス・レンズの移動方向に一致していると判定されたことに応じて，前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて前記フォーカス・レンズを移動するように前記フォーカス・レンズ移動部を制御する第３の移動制御部，
    　をさらに備えた請求項１から３のうち，いずれか一項に記載のオート・フォーカス装置。     The first focus evaluation value signal output from the first focus evaluation value output unit or the first focus evaluation value signal after the focus lens is positioned at a position where the subject image is in focus by the focus lens moving unit. The first focus evaluation value output from the first focus evaluation value output unit in response to a change in the second focus evaluation value signal output from the second focus evaluation value output unit. Based on the signal, the position of the focus lens is farther from the in-focus position than the threshold position, and the moving direction of the focus lens represented by the first focus evaluation value signal and the position of the focus lens A first determination unit configured to determine whether or not the movement direction of the focus lens represented by a second focus evaluation value signal is matched; and the position of the focus lens by the first determination unit Is a position farther from the in-focus position than the threshold position, and is expressed by the moving direction of the focus lens and the second in-focus evaluation value signal represented by the first in-focus evaluation value signal. The focus based on the first focus evaluation value signal output from the first focus evaluation value output unit in response to the determination that the direction of movement of the focus lens is the same. A third movement control unit that controls the focus lens moving unit to move the lens;
    The autofocus device according to any one of claims 1 to 3, further comprising:
  5. 　前記フォーカス・レンズ移動部により前記フォーカス・レンズが，被写体像が合焦する位置に位置決めされた後に，前記第１の合焦評価値出力部から出力される第１の合焦評価値信号または前記第２の合焦評価値出力部から出力される第２の合焦評価値信号が変化したことに応じて，前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて前記フォーカス・レンズの位置が，前記しきい値位置よりも合焦位置に近い位置となり，かつ前記第１の合焦評価値信号によって表される前記フォーカス・レンズの移動方向および前記第２の合焦評価値信号によって表される前記フォーカス・レンズの移動方向に一致していないどうかを判定する第２の判定部，および
    　前記第２の判定部によって前記フォーカス・レンズの位置が，前記しきい値位置よりも合焦位置から近い位置となり，かつ前記第１の合焦評価値信号によって表される前記フォーカス・レンズの移動方向および前記第２の合焦評価値信号によって表される前記フォーカス・レンズの移動方向に一致していないと判定されたことに応じて，前記第２の合焦評価値出力部から出力される第２の合焦評価値信号にもとづいて前記フォーカス・レンズを移動するように前記フォーカス・レンズ移動部を制御する第４の移動制御部，
    　をさらに備えた請求項１から４のうち，いずれか一項に記載のオート・フォーカス装置。     The first focus evaluation value signal output from the first focus evaluation value output unit or the first focus evaluation value signal after the focus lens is positioned at a position where the subject image is in focus by the focus lens moving unit. The first focus evaluation value output from the first focus evaluation value output unit in response to a change in the second focus evaluation value signal output from the second focus evaluation value output unit. Based on the signal, the position of the focus lens is closer to the in-focus position than the threshold position, and the moving direction of the focus lens represented by the first focus evaluation value signal and the A second determination unit that determines whether or not the movement direction of the focus lens represented by a second focus evaluation value signal is coincident, and the position of the focus lens is determined by the second determination unit; , The position closer to the in-focus position than the threshold position, and represented by the moving direction of the focus lens and the second in-focus evaluation value signal represented by the first in-focus evaluation value signal. In response to the determination that the direction of movement of the focus lens does not match, the focus and focus values are output from the second focus evaluation value output unit based on the second focus evaluation value signal. A fourth movement control unit for controlling the focus / lens moving unit to move the lens;
    The autofocus device according to any one of claims 1 to 4, further comprising:
  6. 　第１の合焦評価値出力部が，フォーカス・レンズを通って入射する光が瞳分割により二つに分けられて結像する二つの被写体像の瞳分割方向の位置ずれ量にもとづいてピントのずれ量を示す第１の合焦評価値信号を出力し，
    　第２の合焦評価値出力部が，前記フォーカス・レンズを通って入射する光の光路において，光路長が互いに異なる位置に配置された第１の撮像素子および第２の撮像素子のそれぞれの出力信号とにもとづいてピントのずれ量を示す第２の合焦評価値信号を出力し，
    　フォーカス・レンズ移動部が，前記フォーカス・レンズの位置が，被写体像が合焦する位置近傍のしきい値以上に被写体像が合焦する位置から離れている場合は前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて前記フォーカス・レンズを移動し，前記フォーカス・レンズが前記しきい値位置よりも被写体像が合焦する位置に近い場合は前記第２の合焦評価値出力部から出力する第２の合焦評価値信号にもとづいて前記フォーカス・レンズを，被写体像が合焦する位置に位置決めし，
    　位置判定部が，前記フォーカス・レンズ移動部によって前記フォーカス・レンズが位置決めされた位置が，被写体像が合焦する前記フォーカス・レンズの位置かどうかを，前記第１の合焦評価値出力部から出力した第１の合焦評価値信号にもとづいて判定し，
    　移動制御部が，前記第１の位置判定部によって，前記フォーカス・レンズ移動部によって前記フォーカス・レンズが位置決めされた位置が，被写体像が合焦する前記フォーカス・レンズの位置ではないと判定されたことに応じて，前記第１の合焦評価値出力部から出力される第１の合焦評価値信号にもとづいて前記フォーカス・レンズを移動するように前記フォーカス・レンズ移動部を制御する，
    　オート・フォーカス装置の動作制御方法。     The first focus evaluation value output unit is configured to focus on the amount of positional deviation in the pupil division direction of the two subject images formed by dividing the light incident through the focus lens into two by pupil division. Outputting a first focus evaluation value signal indicating the amount of deviation;
    The second focus evaluation value output unit outputs each of the first image sensor and the second image sensor that are arranged at different positions in the optical path of light incident through the focus lens. A second focus evaluation value signal indicating the amount of focus deviation is output based on the signal;
    When the focus / lens moving unit is away from a position where the subject image is focused more than a threshold value near a position where the subject image is focused, the first focus evaluation value The focus lens is moved based on the first focus evaluation value signal output from the output unit, and the focus lens is closer to the position where the subject image is in focus than the threshold value position. Positioning the focus lens at a position where the subject image is in focus based on the second focus evaluation value signal output from the focus evaluation value output unit 2;
    The position determination unit determines whether the position where the focus lens is positioned by the focus / lens moving unit is the position of the focus lens where the subject image is in focus, from the first focus evaluation value output unit. Judgment based on the output first focus evaluation value signal,
    The movement control unit is determined by the first position determination unit that the position where the focus lens is positioned by the focus lens moving unit is not the position of the focus lens at which the subject image is focused. Accordingly, the focus lens moving unit is controlled to move the focus lens based on a first focus evaluation value signal output from the first focus evaluation value output unit.
    Operation control method of auto focus device.
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JP2007304188A (en) * 2006-05-09 2007-11-22 Sony Corp Imaging apparatus and af module
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JP2005234325A (en) * 2004-02-20 2005-09-02 Canon Inc Lens controller, imaging device, and lens control method
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