JP2001075137A - Image blur correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the stable time for detecting a shake of the optical axis of optical equipment in an image blur correcting device. SOLUTION: A capacitor C1 is connected to an angular velocity sensor 51 through a switch 101. A resistance R11 is connected to the sensor 51 through a switch 102, and a resistance R12 is connected to the sensor 51 through a switch 103. The switches 101 and 102 and the resistance R11, and the switch 103 and the resistance R12 are connected in parallel. The capacitor C1 is connected to the non-inverted input terminal of a buffer amplifier 104, and the output terminal of the amplifier 104 is connected to the non-inverted input terminal of a differential amplifier circuit 105. The sensor 51 is connected to the inverted input terminal of the circuit 105. The output terminal of the circuit 105 is connected to an A/D conversion port AD1. The same circuit is constituted concerning an angular velocity sensor 52. Immediately after applying the power source of a camera, the switches 101 and 111 are turned on and the switches 102, 103, 112 and 113 are turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image blur correction device for correcting an image blur of an optical device due to a camera shake or the like.

[0002]

2. Description of the Related Art A conventional image blur correction device integrates an output signal of an angular velocity sensor provided as a blur detection means to calculate a blur amount, and is provided in an optical path of a photographing optical system based on the calculation result. By driving the correction optical system, the movement of the subject image on the imaging plane of the camera, for example, the film plane or the imaging plane of the photoelectric conversion element is corrected.

For example, a gyro sensor is used as the angular velocity sensor. The output signal of the gyro sensor is already processed by an electronic circuit in the sensor, and a so-called null voltage is output even in a stationary state. That is, the output of the angular velocity sensor does not become “0” even when there is no camera shake. Further, the output of the angular velocity sensor includes a DC component (offset). Since the value of this DC component is not negligible compared to the angular velocity due to camera shake, and is also affected by the temperature and the passage of time, if the output of the angular velocity sensor is used as it is, the fluctuation detected by the influence of the DC component Quantities can contain large errors. Therefore, in order to remove only the DC component from the sensor output and obtain only an output corresponding to the angular velocity, a high-pass type CR DC cut circuit composed of a capacitor and a resistor is generally connected to the angular velocity sensor. Further, the removal of the null voltage is also performed by a CR direct current cut circuit.

[0004]

However, in a high-pass type CR DC cut circuit, the cutoff frequency to be cut is determined according to the time constant, and the removal of the null voltage is completed by the time constant according to the time constant. Has a problem that a predetermined time is required. Therefore, when such an image blur correction device is mounted on a camera, for example, the photographing operation is performed after the null voltage has been removed, so that a shutter chance is missed, or the null voltage cannot be removed. Since the image blur correction is performed in a sufficient state, a problem such as a decrease in correction accuracy has been caused.

An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide an image blur correction apparatus capable of performing highly accurate image blur correction immediately after starting use.

[0006]

SUMMARY OF THE INVENTION An image blur correction apparatus according to the present invention comprises: a blur detection means for detecting a blur of an optical axis of an optical apparatus; a correction optical system for correcting a blur of an optical axis; A driving unit that drives the system, and a control unit that controls the driving unit such that the correction optical system is driven to follow the blur of the optical axis so as to eliminate the blur of the observation body image caused by the blur of the optical axis,
DC cut means for outputting a signal obtained by cutting a DC component included in the output signal from the output signal of the blur detection means,
And a shake detection initializing means for initializing an output signal of the shake detecting means.

Preferably, the DC cut means includes a resistor having a predetermined resistance value, a capacitor, an input signal input from a first signal line connected to the shake detection means, and a shake via the resistor and the capacitor. Differential means for calculating and outputting a difference from an input signal input from a second signal line connected to the detecting means, wherein the initializing means short-circuits a resistor in the second signal line, and includes only a capacitor. Intervene.

Preferably, the DC cut means has cut-off frequency switching means for switching the frequency of a frequency component cut from the output signal.

Preferably, the DC cut means is connectable between the shake detecting means and the capacitor, and a first resistor connectable between the shake detecting means and the capacitor.
A second resistor having a resistance value larger than the resistance value of the resistor, the initializing means includes first switch means for connecting the shake detecting means and the capacitor in series, and the cutoff frequency switching means includes There are provided second switch means for interposing a first resistor between the detecting means and the capacitor, and third switch means for interposing a second resistor between the blur detecting means and the capacitor.

[0010] Preferably, the first signal line is connected to the first signal line.
Is connected in series, the second resistor and the capacitor are connected in series, and the first switch means, the second
The switch means and the first resistor, and the third switch means and the second resistor are connected in parallel with each other, the first switch means is closed, and the second switch means and the third switch means When opened, the output signal of the shake detecting means is initialized by the calculation in the differential means, and more preferably, only the first switch means is closed immediately after the power of the optical apparatus is turned on.

[0011] Further, the image blur correction apparatus according to the present invention comprises:
A shake detecting unit that detects a shake of an optical axis of the optical apparatus, a correction optical system for correcting the shake of the optical axis, a driving unit that drives the correction optical system, and an image of an observation object caused by the shake of the optical axis. A control unit for controlling the driving unit so that the correction optical system is driven to follow the shake of the optical axis so as to eliminate the shake; an input signal input from a first signal line connected to the shake detection unit; Differential means for calculating and outputting a difference between a resistor having a resistance value of: and an input signal input from a second signal line connected to the shake detecting means via a capacitor. When the resistance is short-circuited and the capacitor and the shake detecting means are directly connected, the output signal of the shake detecting means is initialized by the operation of the differential means.

As described above, in the image blur correction apparatus according to the present invention, the CR circuit is configured to remove a DC component from the output signal of the optical axis blur detection means, and the switch means is provided immediately after the power of the optical apparatus is turned on. By operating, the resistance of the CR circuit is short-circuited, and the output signal of the shake detecting means is instantaneously initialized. Therefore, it does not take a long time to remove the null voltage included in the output signal of the shake detecting means. Therefore, when the image blur correction device of the present invention is mounted on a camera, a photographing operation with image blur correction control can be started immediately after the camera is turned on.

The image blur correction device of the present invention can be mounted not only on a single-lens reflex camera or a compact camera but also on a video camera.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In this specification, a plane parallel to the film surface of the camera in a state where the camera is held horizontally so that the optical axis of the interchangeable lens is horizontal is referred to as a "vertical plane". Intersects the shooting optical axis,
The axis dividing the camera in the vertical direction is called “horizontal axis a”, and the axis dividing the camera into left and right is called “vertical axis b”.

FIG. 1 shows a camera 1 having an image blur correction function according to this embodiment. The camera 1 includes an objective optical system 2, an image blur correction unit 40, a quick return mirror 3,
Viewfinder optical system 4, AF sensor 7, sub mirror 8,
The camera includes a shutter button 20, a film F on which a subject image is formed, and control means 30 for controlling the entire camera 1. A correction lens 401 (correction optical system) is provided in the image blur correction means 40.
Is provided. In the camera 1, the photographing optical system includes an objective optical system 2 and a correction lens 401. After passing through the objective optical system 2 and the correction lens 401, the subject light enters the quick return mirror 3. The subject light reflected by the quick return mirror 3 is guided to the photographer's eyes by the finder optical system 4, and the subject light transmitted through the quick return mirror 3 is reflected by the sub mirror 8 and guided to the AF sensor 7. The details of the image blur correction means 40 and the correction lens 401 will be described later.

The camera 1 has angular velocity sensors 51 and 52 functioning as shake detecting means for detecting shake of the photographing optical system 2 with respect to a subject, and a lens for detecting movement of a lens in the photographing optical system 2 in the optical axis direction. A movement detecting means 60 is provided.

The shutter button 20 is a two-stage switch, and the photometry switch is turned on when the shutter button 20 is depressed one stage.
Then, when it is pushed in two steps, the release switch is turned on.
The ON / OFF information of these switches is transmitted to the control unit 30.
Is input to

The angular velocity sensor 51 detects the angular velocity of the rotational movement of the camera in the vertical direction (vertical direction) in FIG. 1, and outputs a voltage to the control means 30 according to the angular velocity in the direction due to camera shake or the like. The angular velocity sensor 52 is a sensor that detects the angular velocity of the rotational movement of the camera in a direction (horizontal direction) perpendicular to the paper surface of FIG. 1, and outputs a voltage corresponding to the detected angular velocity to the control unit 30.

The image blur correcting means 40 constitutes a part of the photographing optical system as described above, and includes a correcting lens 401 for deflecting the optical axis of the photographing optical system and a driving means for driving the correcting lens 401. It is configured. The driving unit drives the correction lens 401 based on a command from the control unit 30 so as to cancel the movement of the subject image formed by the photographing optical system on the film surface, and makes the optical axis of the photographing optical system perpendicular to the paper. In independent directions and in a direction parallel to the plane of the paper.

During photographing, the control means 30 drives the image blur correction means 40 based on the input signals from the angular velocity sensors 51 and 52, so that the image blur on the film surface F and in the finder field of view. Is corrected.

Although the objective optical system 2 is shown as a single lens in FIG. 1, it is actually composed of a plurality of lenses or a plurality of lens groups, and a part of the objective lens is used for focusing or zooming. , Or all are movable in the optical axis direction. In the first embodiment, the lens movement detection unit 60 detects a movement for focusing of a lens group related to focusing (hereinafter, referred to as a “focusing lens”) among the lenses constituting the objective optical system 2.

At the time of observation, the quick return mirror 3 is shown in FIG.
Is positioned at the position shown in FIG. Therefore, the objective optical system 2 including the focusing lens and the image blur correcting means 40
The luminous flux of the subject incident through the correction lens 401 of
The light is reflected by the quick return mirror 3 and guided to the focusing screen B. The image of the subject on the reticle B is inverted by the pentaprism 4, and the observer can observe the image on the reticle B as an erect image via the eyepiece lens 9. That is, in the present embodiment, the finder optical system
An objective optical system 2 including a focusing lens, a correction lens 401, a quick return mirror 3, a reticle B, a pentaprism 4, and an eyepiece lens 9 are provided.

The quick return mirror 3 and the sub-mirror 8 are retracted to a position facing the focusing screen B by a mirror driving mechanism (not shown) at the time of photographing. As a result, at the time of shooting, the luminous flux of the subject is guided to the film surface F via the objective optical system 2 including the focusing lens and the correction lens 401, and a subject image is formed on the film surface F. In this manner, the subject image is exposed on the film surface F, and the recording of the subject image is performed.

The focusing lens is configured to move in the optical axis direction by a known cam mechanism (not shown) by rotating the lens barrel 5. The lens barrel 5 is rotated by a motor provided on the body or the lens unit of the camera 1 or by a manual operation of the focusing operation ring 55 of the photographer himself.

The AF sensor 7 is a conventionally known sensor for detecting a defocus amount of the photographing optical system by a phase detection method. An image sensor (not shown) in the AF sensor 7 is disposed at a position optically equivalent to the reticle B and the film surface F. Therefore, the focus state on the reticle B is the film plane F
The focus state is equivalent to the above focus state, and when the image on the reticle B formed by the photographing optical system is formed, in other words, when the focal position of the photographic optical system coincides with the reticle B, focus is achieved. State.

The AF sensor 7 detects, as a defocus amount, a focus state of an image on a film plane F (planned focal plane) formed by the photographing optical system. That is, the AF sensor 7
Detects the amount of defocus indicating in which direction on the optical axis the focus position of the image formed by the photographing optical system is shifted from the reticle B or the film surface F at the present time. The control unit 30 calculates the driving direction and the driving amount of the focusing lens based on the defocus amount detected by the AF sensor 7, and the focusing lens is driven based on the calculation result of the control unit 30, and the automatic focus adjustment is performed. Done.

The lens movement detecting means 60 includes a pinion gear 61 meshing with a rack 5a provided on the outer periphery of the lens barrel 5.
And a slit plate 6 provided coaxially with the pinion gear.
2 and a photo interrupter 63 provided with the slit plate 62 interposed therebetween. The slit plate 62 is provided with a number of slits radially about the rotation axis. The photo interrupter 63 includes a light emitting unit 63a and a light receiving unit 63b opposed to each other with a slit plate interposed therebetween, and a periodic signal corresponding to the brightness of light is output from the light receiving unit 63b as the slit plate 62 rotates. Is done.
As described above, the lens barrel 5 is rotated by the motor provided on the body or the lens unit of the camera 1 in the case of auto focus, and is rotated manually by the photographer in the case of manual focus. Therefore, the slit plate 62 interlocked with the rotation of the lens barrel 5 by focusing.
A pulse signal is output from the light receiving section 63b in accordance with the rotation of.

FIG. 2 shows the structure of the image blur correcting means 40. The correction lens 401 constituting the correction optical system is fixed to the first rotation plate 420 while being fitted in the lens frame 410, and the first rotation plate 420 is connected to the second rotation plate 430 via the rotation shaft 421. To be rotatable. Further, the second rotation plate 430 is rotatably attached to the substrate 440 via a rotation shaft 431 projecting 90 degrees away from the rotation shaft 421 about the optical axis O of the photographing optical system. Substrate 440
Is fixed to the camera 1.

With the above configuration, the correction lens 401
The rotation of the first and second rotation plates 420 and 430 causes the optical axis O
Are held so as to be displaceable in the directions indicated by arrows H and V in the figure in a plane perpendicular to the direction.

The lens frame 410 has a large diameter part 411 and a small diameter part 412, and the small diameter part 412 is fitted into the opening 422 of the first rotating plate 420. Rotation axis 4 of first rotation plate 420
21 is inserted into a shaft hole 439 formed in the second rotation plate 430. An arm 424 having a screw hole 423 is provided on the opposite side of the rotation shaft 421 across the opening 422.

A screw member 426 connected to the rotating shaft of the motor 425 via a flexible joint is screwed into the screw hole 423. The motor 425 is connected to the second rotating plate 4
It is fixed on 30. When the motor 425 is driven, the first rotation plate 420 is driven to rotate about the rotation shaft 421 in the direction indicated by the arrow V in accordance with the rotation direction of the screw member 426.

At the tip of the drive arm 424, a permanent magnet 4
The MR (Magnetic) for detecting the position of the permanent magnet 427 is provided on the second rotating plate 430.
Resistance) sensor 428 is
7 is provided. The control unit 30 detects the displacement of the lens 401 in the direction of the arrow V based on the output signal of the MR sensor 428.

The rotation shaft 431 of the second rotation plate is connected to the substrate 440
Is inserted into the shaft hole 449 formed in the hole. Second rotating plate 43
0 has an opening 432 through which the small diameter portion 412 is inserted. The opening 432 has a size that does not hinder the movement of the small diameter portion 412 due to the rotation of the first rotation plate 420 when the first rotation plate 420 is assembled to the second rotation plate 430.

A drive arm 434 having a screw hole 433 is provided on the opposite side of the rotation shaft 431 with the opening 432 interposed therebetween. A screw member 436 connected to the rotation shaft of the motor 435 via a flexible joint is screwed into the screw hole 433. When the motor 435 is driven, the second rotation plate 430 is driven to rotate about the rotation shaft 431 in the direction indicated by the arrow H in accordance with the rotation direction of the screw member 436.

At the tip of the drive arm 434, a permanent magnet 4
An MR sensor 438 is provided on the substrate 440. The control means 30 includes the MR sensor 4
The displacement of the lens 401 in the direction of the arrow H is detected based on the output signal of 38.

The substrate 440 is provided with an opening 442 through which the small diameter portion 412 is inserted. The opening 442 has a size that does not hinder the movement of the small diameter portion 412 due to the rotation of the first and second rotation plates.

FIG. 3 shows the image blur correcting means 40 viewed from the objective optical system 2 in a state where the above-described lens frame 410, the first rotating plate 420, the second rotating plate 430, and the substrate 440 are combined. FIG. FIG. 3 shows a reference state in which the optical axis of the correction lens 401 matches the optical axis O of the photographing optical system. In the reference state, the center of the rotation shaft 421 of the first rotation plate 420, the optical axis O, the permanent magnet 427, and the MR sensor 428 are aligned on a straight line a. Similarly, the center of the rotation shaft 431 of the second rotation plate 430,
The optical axis O, the permanent magnet 437, and the MR sensor 438 are arranged on the straight line b.

FIG. 4 is a block diagram for explaining input / output signals of the CPU 31 constituting the control means 30 described above.
The ON / OFF information of the photometric switch 21 and the release switch 22 linked to the shutter button 20 is converted into a 1-bit digital pulse as a 1-bit digital pulse.
11 and input to P12. MR sensors 428, 438
Are input to A / D conversion ports AD3 and AD4, respectively.

D / A output ports DA1, D of CPU 31
A2 is connected to a motor 425 for driving the first rotating plate 420 and a motor 435 for driving the second rotating plate 430 via motor driving circuits 461 and 462, respectively. The CPU 31 determines the amount of movement of the correction lens required to correct the image blur based on the above-described input signal.
5. Calculate by converting to the driving amount of the motor 435,
A1 and DA2 output a voltage corresponding to the driving amount.

The output signal of the angular velocity sensor 51 is the signal line 11
L (a first signal line) and a signal line 12L (a second signal line). The signal line 11L connects the angular velocity sensor 51 to the inverting input terminal (-) of the differential amplifier circuit 105 (differential means) via a resistor. The output terminal of the differential amplifier circuit 105 is connected to an inverting input terminal via a resistor to form a negative feedback circuit, and is connected to the A / D conversion port AD1 of the CPU 31.

In the signal line 12L, the grounded capacitor C1 is connected in series to the angular velocity sensor 51 via the analog switch 101 (first switch means). The resistor R11 (first resistor) is connected to the analog switch 10
2 (second switch means) and the resistor R12
The (second resistor) is connected in series to the angular velocity sensor 51 via the analog switch 103 (third switch means). Analog switch 101, analog switch 102 and resistor R11, and analog switch 1
03 and the resistor R12 are connected in parallel with each other. The analog switch 101 is connected to the port P2 of the CPU 31.
1, the analog switch 102 is connected to the port P22, and the analog switch 103 is connected to the port P23. That is, ON / OFF control of each analog switch is performed based on a control signal output from the CPU 31.

Non-inverting input terminal (+) of buffer amplifier 104
Is connected to a non-inverting input terminal of the differential amplifier circuit 105 via a resistor.

A circuit having the same configuration as the angular velocity sensor 51 is also connected to the angular velocity sensor 52. The output signal of the angular velocity sensor 52 is branched into a signal line 21L (first signal line) and a signal line 22L (second signal line). Signal line 21
L connects the angular velocity sensor 52 to the inverting input terminal of the differential amplifier 115 (differential means).
Is connected to the A / D conversion port AD2 of the CPU 31. In the signal line 22L, the angular velocity sensor 5
2 includes analog switches 11 connected in parallel with each other.
1, 112 and 113 are connected and the analog switch 1
11 is directly connected to the capacitor C2, and the analog switches 112 and 113 are connected to the capacitor C2 via resistors R21 and R22, respectively. Buffer amplifier 1
The capacitor C2 is connected to the non-inverting input terminal of the No. 14
The output terminal is connected to a non-inverting input terminal of the differential amplifier circuit 115 via a resistor.

As described above, in the differential amplifier circuit 105, the signal output from the angular velocity sensor 51 and input to the inverting input terminal via the signal line 11L and the angular velocity sensor 5
1 is amplified through a capacitor C1 connectable to the signal line 12L and input to a non-inverting input terminal via resistors R11 and R12. Similarly, in the differential amplifier circuit 115, a signal output from the angular velocity sensor 52 and input to the inverting input terminal via the signal line 21L and a capacitor C2 output from the angular velocity sensor 52 and connectable to the signal line 22L, The differential amplification with the signal input to the non-inverting input terminal via the resistors R21 and R22 is performed.

When the photometric switch 21 is turned on by half-pressing the shutter button 20 and an ON signal is input to the input port P11, the CPU 31 executes a photometric operation of subject light via a photometric mechanism (not shown) to execute an exposure value. (Ev) is calculated, and the aperture value (A) required for photographing is calculated based on the exposure value.
v) and the exposure time (Tv) are calculated. Further, when the release switch 22 is turned on by fully pressing the shutter button 20, and an ON signal is input to the input port P12, C is released.
The PU 31 drives the diaphragm (not shown) of the photographing lens to stop down in accordance with the above-mentioned diaphragm value, drives the quick return mirror 3 up, and drives the shutter mechanism (not shown) at a predetermined shutter speed.

FIG. 5 is a flowchart showing a processing procedure for controlling image blur correction in the camera 1. When the power of the camera 1 is turned on, the process is started, and the process proceeds to step S500.
, Switch ON from port P21 of CPU31
, And a switch OFF control signal is output from the ports P22 and P23. That is, the switch 101 and the switch 111 are closed, and the switch 10
2, 103, 112 and 113 are opened.

As a result, the output voltage V of the angular velocity sensor 51
1v is charged in the capacitor C1, and the value of the output voltage V2v of the buffer amplifier 104 becomes the same as V1v. Therefore, the voltage value of the inverting input terminal and the voltage value of the non-inverting input terminal of the differential amplifier 105 are both the output voltage V1 of the angular velocity sensor 51.
v, and the voltage value of the output voltage V3v of the differential amplifier 105 becomes “0”. Similarly, the output voltage V1h of the angular velocity sensor 52 is charged in the capacitor C2, and the buffer amplifier 114
Of the output voltage V2h is the same as V1h. Therefore,
Both the voltage value at the inverting input terminal and the voltage value at the non-inverting input terminal of the differential amplifier 115 are the output voltage V of the angular velocity sensor 52.
1h, and the voltage value of the output voltage V3h of the differential amplifier 115 becomes “0”.

That is, by the ON / OFF control of the switch in step S500, the A / D conversion input terminal AD1
And the value input to AD2 is “0”. In other words, immediately after the camera 1 is turned on, the angular velocity sensor 5
An effect equivalent to eliminating the null voltage contained in the outputs of 1 and 52 is obtained. As a result, the subsequent image blur correction control is started from a state where the optical axis of the correction lens 401 is coincident with the optical axis of another optical system of the camera 1, so that highly accurate image blur correction is performed. .

In step S502, "0" is set to a digital swing displacement value V5v in the vertical direction and a digital swing displacement value V5h in the horizontal direction, which will be described later, to initialize.

In step S504, a switch ON control signal is output from the port P22, and the ports P21 and P
23 outputs a switch OFF control signal. That is, the switches 102 and 112 are closed, the switches 101, 103, 111 and 113 are opened,
A CR DC cutoff circuit (integration circuit) including the resistor R11 and the capacitor C1 and a CR DC cutoff circuit (integration circuit) including the resistor R21 and the capacitor C2 are formed. The resistance values of the resistors R11 and R21 are equal to the resistance R12,
It is set smaller than the resistance value of R22. Therefore,
A time constant defined by the resistor R11 and the capacitor C1,
The time constant defined by the resistor R21 and the capacitor C2 has a relatively small value.

As a result, the cutoff frequency cut by the CR DC cutoff circuit including the resistor R11 and the capacitor C1 is set relatively high. Similarly, the resistor R2
1. The cutoff frequency cut by the CR DC cutoff circuit comprising the capacitor C2 is set relatively high. Therefore, when a large DC component is included in the output voltages of the angular velocity sensors 51 and 52 as in a case where a pan operation for determining a composition is performed before the shutter button 20 is depressed two steps and a shooting operation is started, DC components are quickly removed.

The output voltage V3v from the output voltage V1v of the angular velocity sensor 51 to a relatively high frequency component is cut.
Is output by the differential amplifier 105, and A /
An output voltage V3h, which is input to the D conversion port AD1 and has a relatively high frequency component cut from the output voltage V1h of the angular velocity sensor 52, is output by the differential amplifier 115 and input to the A / D conversion port AD2 of the CPU 31. .

Next, in step S506, it is checked whether the photometric switch 21 is ON. If the photometry switch 21 is ON, the process proceeds to step S508, where photometry is performed, and an aperture value, an exposure time, and the like are calculated by calculation.

Next, at step S510, it is checked whether or not the release switch 22 is ON. If the release switch 22 is off, the process returns to step S506; if it is on, the process proceeds to step S512. That is, until the release switch 22 is turned on, step S50 is performed.
6 and S508 are repeated.

When the release switch 22 is turned on by fully pressing the shutter button 20, and an ON signal is input to the input port P12, the process proceeds to step S512, where the CPU 3
Reference numeral 1 drives the aperture mechanism in accordance with the above-described aperture value, drives the quick return mirror 3 up, and drives the shutter mechanism to release at a predetermined shutter speed.

In step S514, a switch ON control signal is output from port P23, and ports P21 and P
A switch OFF control signal is output from 22. That is, the switches 103 and 113 are closed, the switches 101, 102, 111 and 112 are opened,
A CR DC cut circuit including the resistor R12 and the capacitor C1 and a CR DC cut circuit including the resistor R22 and the capacitor C2 are formed.

As described above, the resistors R12 and R22
Are larger than the resistance values of the resistors R11 and R21, respectively. Therefore, CR including the resistor R12 and the capacitor C1
The time constant of the DC cutoff circuit is the resistance R11 and the capacitor C
The time constant of the CR DC cut circuit composed of the resistor R22 and the capacitor C2 is larger than the time constant of the CR DC cut circuit composed of the resistor R22 and the capacitor C2.

That is, the cut-off frequency cut by the CR DC cut circuit including the resistor R12 and the capacitor C1 is lower than the cut-off frequency cut by the CR DC cut circuit including the resistor R11 and the capacitor C1. Similarly, CR including a resistor R22 and a capacitor C2
The cut-off frequency cut by the DC cut circuit is lower than the cut-off frequency cut by the CR DC cut circuit including the resistor R21 and the capacitor C2. Therefore, when the camera is already pointed at the subject, such as during exposure, a relatively low frequency component of the output of the angular velocity sensor is reflected on image blur correction without being cut. As a result, more accurate image blur correction is performed.

The output voltage V3v from the output voltage V1v of the angular velocity sensor 51 to a relatively low frequency component is cut.
Is output by the differential amplifier 105, and A /
The output voltage V3h, which is input to the D conversion port AD1 and has a relatively low frequency component cut from the output voltage V1h of the angular velocity sensor 52, is output by the differential amplifier 115,
The signal is input to the A / D conversion port AD2 of the PU 31.

In step S516, ports AD1 and A
The angular velocities V3v and V3h input to D2 are A / D-converted and set to a digital detection value V4v in the vertical axis direction and a digital detection value V4h in the horizontal axis direction, respectively.

Next, in step S518, by integrating the digital detection value V4v in the vertical axis direction, a digital swing displacement value V5v for defining the swing position of the first rotary plate 420 along the vertical axis b is obtained. Is calculated, and a digital swing displacement value V5h for defining a swing position of the second rotating plate 430 along the horizontal axis a is calculated by integrating the digital detection value V4h in the horizontal axis direction.

Next, in step S520, the MR sensor 4
The output voltage of the A / D converter 28 is A / D-converted at an AD conversion input terminal AD3, and is set to a digital current position detection value V6v in the V direction of the current correction lens 401. The output voltage of the MR sensor 438 is A / D converted at an AD conversion input terminal AD4. D-converted and current digital detected position value V of H direction of correction lens 401
Set to 6h.

In step S522, the first rotating plate 420
Digital swing drive value V in the vertical axis direction from the current position of
7v, that is, to calculate the drive amount of the motor 425,
The digital current position detection value V6v is subtracted from the digital swing displacement value V5v in the vertical axis direction. Second rotating plate 430
Digital swing drive value V in the horizontal axis direction from the current position of
7h, that is, to calculate the drive amount of the motor 435,
The digital current position detection value V6h is subtracted from the digital swing displacement value V5h in the horizontal axis direction.

Next, in step S524, the digital swing drive value V7v in the vertical axis direction is digitally / analog converted and output as an analog signal from the first digital / analog conversion output terminal DA1, and the digital swing drive value V7v in the horizontal axis direction is obtained. The drive value V7h is digital-to-analog converted and output as an analog signal from the second digital / analog conversion output terminal DA2.

First digital / analog conversion output terminal D
The analog swing drive signal output from A1 is amplified by the motor drive circuit 461 and then output to the motor 425. The motor 425 oscillates the first rotary plate 420 based on the input analog oscillating drive signal. As a result, the correction lens 401 is moved and driven along the vertical axis b so as to cancel the vertical axis component of the image blur caused by camera shake.

Second digital / analog conversion output terminal D
The analog swing drive signal output from A2 is amplified by the motor drive circuit 462 and then output to the motor 435. The motor 435 oscillates the second rotating plate 430 based on the input analog oscillating drive signal. As a result, the correction lens 401 is driven and moved along the horizontal axis a so as to cancel the horizontal axis component of the image blur caused by camera shake.

In step S526, step S5
It is determined whether the exposure time calculated in step 08 has elapsed.
If the exposure time has not elapsed, the process returns to step S516, and the subsequent processing is executed again to execute drive control of the motors 425 and 435 for correcting image blur. On the other hand, if it is determined that the exposure time has elapsed, the process proceeds to step S528.
Then, the shutter mechanism is closed and driven, the quick return mirror is driven back to the reflection position, the aperture of the photographing lens is opened, and a series of photographing operations is completed.

As described above, according to the present embodiment, in a state immediately after the power supply to the camera 1 is turned on, the analog switch is operated to short-circuit the resistance constituting the CR DC cutoff circuit, and the angular velocity sensor The output is charging the capacitor. Therefore, in the differential amplifier for removing the DC component included in the output of the angular velocity sensor, the inverting input terminal to which the angular velocity sensor is connected and the non-inverting input terminal to which the capacitor is connected have the same potential. Is initialized. In other words, an effect equivalent to the instantaneous removal of the null voltage included in the output of the angular velocity sensor is obtained. Therefore, after turning on the power of the camera 1,
It is possible to immediately start a photographing operation with high-precision image blur correction control.

[0069]

As described above, according to the present invention, it is possible to obtain an image blur correction apparatus capable of performing high-precision image blur correction immediately at the start of use.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a camera having an image blur correction function according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a correction lens driving mechanism of the camera according to the embodiment.

FIG. 3 is a front view of the drive mechanism of FIG. 2 as viewed from a photographing lens.

FIG. 4 is a block diagram illustrating a configuration of a control system for image blur correction according to the embodiment.

FIG. 5 is a flowchart illustrating a processing procedure of a photographing operation of the camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera 2 Photographing optical system 4 Viewfinder optical system 7 AF sensor 20 Shutter button 21 Photometry switch 22 Release switch 30 Control means 31 CPU 40 Image blur correction means 51, 52 Angular velocity sensor 60 Lens movement detection means 401 Correction lens 420 First rotation Plate 430 Second rotating plate 440 Substrate

Claims (7)

[Claims] 1. A blur detecting means for detecting a blur of an optical axis of an optical device; a correcting optical system for correcting the blur of the optical axis; a driving means for driving the correcting optical system; Control means for controlling the drive means so that the correction optical system is driven to follow the shake of the optical axis so as to eliminate the shake of the observation body image caused by the shake, and output from an output signal of the shake detection means An image blur correction unit comprising: a DC cut unit that outputs a signal obtained by cutting a DC component included in a signal; and a shake detection initialization unit that initializes an output signal of the shake detection unit. 2. The method according to claim 1, wherein the DC cut means includes a resistor having a predetermined resistance value, a capacitor, an input signal input from a first signal line connected to the shake detecting means, and the resistor and the capacitor. Differential means for calculating and outputting a difference from an input signal input from a second signal line connected to the blur detection means via the second signal line, wherein the initialization means 2. The image blur correction unit according to claim 1, wherein a resistor is short-circuited and only the capacitor is interposed. 3. The DC cutoff means has cutoff frequency switching means for switching the frequency of a frequency component cut from the output signal.
2. An image blur correction unit according to claim 1. 4. The method according to claim 1, wherein the DC cutoff means includes: a first resistor connectable between the shake detection means and the capacitor; and a first resistor connectable between the shake detection means and the capacitor. A second resistor having a resistance value larger than the resistance value of the resistor, wherein the initialization means includes first switch means for connecting the blur detection means and the capacitor in series, and the cut-off frequency switching. A second switch for interposing the first resistor between the blur detecting means and the capacitor; and a third switch for interposing the second resistor between the blur detecting means and the capacitor. 4. The image blur correcting unit according to claim 3, further comprising: a switch unit. 5. In the second signal line, the first resistor and the capacitor are connected in series, the second resistor and the capacitor are connected in series, Second switch means and the first resistor, and the third switch means and the second resistor.
Are connected in parallel with each other, and when the first switch means is closed and the second switch means and the third switch means are opened, the shake detecting means is calculated by the differential means. 5. The image blur correction apparatus according to claim 4, wherein the output signal is initialized. 6. Immediately after turning on the power of the optical device, the first
6. The image blur correction apparatus according to claim 5, wherein only the switch means is closed. 7. A blur detecting means for detecting a blur of an optical axis of an optical device; a correcting optical system for correcting the blur of the optical axis; a driving means for driving the correcting optical system; Control means for controlling the driving means such that the correction optical system is driven to follow the movement of the optical axis so as to eliminate the movement of the observation object image caused by the movement; and a first means connected to the movement detecting means. And calculates and outputs a difference between an input signal input from the second signal line and an input signal input from the second signal line connected to the shake detecting means via a resistor and a capacitor having a predetermined resistance value. Differential means, wherein when the resistor is short-circuited in the second signal line and the capacitor and the shake detecting means are directly connected, the output signal of the shake detecting means is initialized by the operation of the differential means. Characterized to be Image blur correction means.