JP2007127755A - Image stabilizer, optical device, interchangeable lens and camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image stabilizer capable of increasing the kind of image blur which can be restrained. <P>SOLUTION: The image stabilizer is equipped with: first sensors (6p and 6y) detecting vibration applied to a photographing system (2) to form a photographic image; second sensors (5p and 5y) capable of detecting the vibration of frequency higher than the first sensors; and a control part (3) controlling the blur of the photographic image caused by the vibration based on the added value of the results of detection by the first sensors and the second sensors. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image blur correction apparatus mounted on a photographing device such as a video camera or a still camera.

When vibration is applied to a camera system such as a still camera from the outside, the captured image is disturbed (image shake). The main cause of this image blur is a camera shake at the time of hand-held shooting, and the type of vibration is a vibration (angle shake) in a direction in which the shooting system is inclined in the case of a general shooting magnification.
In order to avoid this problem, an image blur correction technique represented by Patent Document 1 has been proposed. This technology is equipped with an angular velocity sensor in the camera system, calculates the angular shake amount (tilt angle) of the imaging system by integrating the output of the angular velocity sensor, and shoots so that the image shake is canceled according to the tilt angle A part of the system is controlled and driven.

Here, although there are various types of sensors for detecting angular shake, a vibration gyro that is an angular velocity sensor that can be miniaturized is suitable for a camera system that is a portable device. The vibration gyro has a vibrator that vibrates at a predetermined frequency, and detects a Coriolis force applied to the vibrator. If the detection band of the vibration gyro is set to a frequency band of camera shake (for example, 3 Hz to 8 Hz), camera shake can be detected.
JP 2000-180911 A

  By the way, even during tripod shooting, image shake may occur due to movement of a mechanism in the camera system such as a quick return mirror or a shutter mechanism. In addition, when shooting on a moving body such as an automobile or a train, there is a possibility that vibration inherent to the moving body is dominant over hand movement. However, the frequency of mechanical vibration by these mechanisms and the moving body is significantly higher than the frequency of camera shake.

On the other hand, the angular velocity detection band by the vibration gyro is almost specified by the material of the vibrator and the vibration frequency, so that it is technically difficult to detect both hand shake and mechanical vibration. For this reason, the current image blur correction device may not be able to suppress image blur depending on the shooting situation.
SUMMARY An advantage of some aspects of the invention is that it provides an image blur correction apparatus that can increase the types of image blur that can be suppressed.

An image shake correction apparatus according to the present invention includes a first sensor that detects vibration applied to a photographing system that forms a photographed image, a second sensor that can detect the vibration having a frequency higher than that of the first sensor, And a control unit configured to control shake of the photographed image due to the vibration based on an addition value of detection results of the first sensor and the second sensor.
The image shake correction apparatus includes low-pass filter means for performing low-pass filter processing on the output signal of the first sensor before addition, and high-pass filter processing on the output signal of the second sensor before addition. The cut-off frequency of the low-pass filter means may be set lower than the cut-off frequency of the high-pass filter means.

The control unit may perform the addition using an analog signal.
The control unit may perform the addition using a digital signal.
The first sensor may be capable of detecting vibration of 3 Hz to 8 Hz.
The first sensor may be a vibration gyro using a single crystal as a vibrator, and the second sensor may be a vibration gyro using ceramic as a vibrator.

The first sensor may use a crystal as a vibrator.
The imaging system may include an amplification type solid-state imaging device.
The image blur correction device may include a buffer member that supports the second sensor and absorbs disturbance.
In addition, an optical apparatus according to the present invention includes any one of the above-described image shake correction apparatuses.

The interchangeable lens according to the present invention includes any one of the above-described image blur correction apparatuses.
The camera system of the present invention includes any one of the above-described image blur correction apparatuses.

  According to the present invention, a high-performance image blur correction apparatus is realized.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The present embodiment is an embodiment of a still camera system.
First, the overall configuration of the camera system will be described with reference to FIG.
FIG. 1 is an overall configuration diagram of the camera system. The Z direction in the coordinate system shown in FIG. 1 corresponds to the direction of the optical axis 100 of the camera system when image blur correction is not in operation, and the Y direction corresponds to the up and down direction of the camera system during horizontal position shooting. Corresponds to the left-right direction of the camera system during horizontal position shooting. In the following, this coordinate system is used as necessary.

As shown in FIG. 1, the camera system includes a camera body 1 and a lens barrel 2 that can be attached to and detached from the camera body 1. The camera body 1 is, for example, a single-lens reflex type still camera equipped with a quick return mirror and a shutter mechanism, and the lens barrel 2 is an interchangeable lens equipped with an image blur correction function.
In the lens barrel 2, as a photographing optical system, for example, a zoom lens having a four-group configuration including a first lens group 201, a second lens group 202, a third lens group 203, and a fourth lens group 204 is used. Is placed. The zooming is performed by changing the positional relationship of the lens groups 201, 202, 203, and 204 in the Z direction, and the focus adjustment is performed by changing the position of the second lens group 202 in the Z direction. . The movement of the lens group at that time is performed by a cam mechanism (not shown) provided in the lens barrel 2.

The lens barrel 2 forms an image of the subject light flux from the object scene on the imaging surface 101 in the camera body 1. The subject image formed on the imaging surface 101 is imaged by an imaging unit such as an amplifying solid-state imaging device such as a silver salt film or CCD / CMOS.
Here, the third lens group 203 has a three-group configuration including lens groups 203 a, 203 b and 203 c, which are housed in the image blur correction unit 3. Among these, the lens group 203b is a correction lens that is driven for image blur correction. Therefore, hereinafter, the lens group 203b is referred to as a “correction lens 203b”.

  The correction lens 203b is supported by the image blur correction unit 3 so as to be movable in the X direction and the Y direction. When the correction lens 203b moves in the XY plane, the positional relationship between the optical axis 100 of the lens barrel 2 and the imaging surface 101 changes, so that the subject image moves on the imaging surface 101. For this purpose, the image blur correction unit 3 includes an actuator 301X that moves the correction lens 203b in the X direction and an actuator 301Y that moves the correction lens 203b in the Y direction. The image blur correction unit 3 also includes a position detection sensor 302X and a position detection sensor 302Y that individually detect the position in the X direction and the position in the Y direction of the correction lens 203b at that time.

Further, the lens barrel 2 is equipped with high-frequency sensors 5p and 5y and low-frequency sensors 6p and 6y in order to detect angular shake applied to the camera system. The fixing points of these sensors are members (fixed cylinders) that do not rotate during zooming or focus adjustment.
Here, the high-frequency sensor 5p and the low-frequency sensor 6p are angular velocity sensors that detect the angular shake velocity (angular velocity) around the X axis (pitch direction) applied to the camera system. Since the angular shake in the pitch direction causes the image shake in the Y direction, the high frequency sensor 5p and the low frequency sensor 6p are used for the image shake correction in the Y direction together with the actuator 301Y and the position detection sensor 302Y.

  The high-frequency sensor 5y and the low-frequency sensor 6y are angular velocity sensors that detect the angular shake velocity (angular velocity) around the Y axis (yaw direction) applied to the camera system. Since the angular shake in the yaw direction causes an image shake in the X direction, the high frequency sensor 5y and the low frequency sensor 6y are used for the image shake correction in the X direction together with the actuator 301X and the position detection sensor 302X described above.

Among these, the detection band of the angular velocity of the high frequency sensors 5p, 5y is set on the high frequency side, and the detection band of the angular velocity of the low frequency sensor 6p is set on the low frequency side.
Next, the detection bands of the high frequency sensors 5p and 5y and the detection bands of the low frequency sensors 6p and 6y will be described in detail with reference to FIG.
2A and 2B are diagrams showing the concept of the detection band of the low frequency sensors 6p and 6y and the concept of the detection band of the high frequency sensors 5p and 5y. 2A and 2B, the horizontal axis represents frequency and the vertical axis represents sensitivity.

First, as shown in FIG. 2A, the detection bands of the low frequency sensors 6p and 6y are set to a range that covers at least the frequency band of camera shake (3 Hz to 8 Hz, preferably 1 Hz to 10 Hz). . The detection band is set to about 1 Hz to about 30 Hz with a margin, for example.
For the low-frequency sensors 6p and 6y having such a detection band, a crystal-type vibration gyro using a crystal as a vibrator is suitable. By appropriately setting the vibration frequency of the vibrator, FIG. 2A or a detection band close thereto can be realized. Such a quartz-type vibrating gyroscope can perform stable detection with a small drift.

  Next, as shown in FIG. 2B, the detection bands of the high frequency sensors 5p and 5y cover at least a mechanical vibration band (30 Hz to 50 Hz, preferably 30 Hz to 100 Hz) and have a low frequency. The range is set so as to partially overlap with the detection bands of the sensors 6p and 6y. The detection band is set to about 20 Hz to about 110 Hz with a margin, for example.

For the high-frequency sensors 5p and 5y having such a detection band, a ceramic-type vibration gyro using ceramic as the material of the vibrator is suitable. By appropriately setting the vibration frequency of the vibrator, FIG. 2B or a detection band close thereto can be realized.
It is also possible to apply ceramic type vibration gyros to both the high frequency sensors 5p and 5y and the low frequency sensors 6p and 6y. In that case, the vibration frequency of the vibrator may be made different between the high frequency sensors 5p and 5y and the low frequency sensors 6p and 6y.

Next, details of the image blur correction unit 3 will be described with reference to FIG.
FIG. 3 is a cross-sectional view of the image blur correction unit 3. FIG. 3 is a cross-sectional view in the YZ plane. In this cross-sectional view, an actuator 301Y that moves the correction lens 203b in the Y direction and a position detection sensor 302Y that detects the position of the correction lens 203 in the Y direction appear. ing.

  As shown in FIG. 3, in the image blur correction unit 3, the lens group 203 a on the front side of the correction lens 203 b is held inside the front lens chamber 304. The lens group 203c on the rear side of the correction lens 203b is held in the rear lens chamber 305. The correction lens 203 b is disposed in a space between the front lens chamber 304 and the rear lens chamber 305 while being held by the holding frame 303.

The front lens chamber 304 and the rear lens chamber 305 are fixed with screws 306, and the holding frame 303 holding the correction lens 203b corrects a gap between the front lens chamber 304 and the rear lens chamber 305 (not shown). It can be moved by a lens driving mechanism. However, the moving direction is limited only to the X direction and the Y direction, and the holding frame 303 does not rotate around the Z axis.
The actuator 301Y is made of, for example, a VCM (Voice Coil Motor), a lower yoke 301a fixed to the front lens chamber 304, a permanent magnet 301b magnetized in two poles on the lower yoke 301a, and a holding frame 303. A loop-shaped coil 301c fixed to the rear lens chamber 305, and an upper yoke 301d fixed to the rear lens chamber 305. According to the lower yoke 301a, the permanent magnet 301b, and the upper yoke 301d, a magnetic circuit is formed in the vicinity of the coil 301c. Therefore, the actuator 301 can move the holding frame 303 (and the correction lens 203b) in the Y direction by supplying a driving current to the coil 301c.

  The position detection sensor 302Y includes, for example, an LED (Light Emitting Diode) 302c attached to the front lens chamber 304, a slit 302b formed in the holding frame 303, and a PSD (Position Sensitive Detector) that receives light that has passed through the slit 302b. ) 302a and a substrate 307 that supports the detection unit 302a and fixes it to the rear lens chamber 305 side. The light emitted from the LED 302c enters the PSD 302a through the slit 302b. When the holding frame 303 (and the correction lens 203b) moves in the Y direction, the slit 302b also moves, so that the output signal of the PSD 302a changes. Therefore, the position detection sensor 302Y can detect the position of the correction lens 203b in the Y direction by driving the LED 302c and the PSD 302a.

  Although not shown in FIG. 3, the actuator 301 </ b> X and the position detection sensor 302 </ b> X are the same as those obtained by rotating the actuator 301 </ b> Y and the position detection sensor 302 </ b> Y around the optical axis 100 by 90 °. The actuator 301X moves the correction lens 203b in the X direction in the same manner as the actuator 301Y moves the correction lens 203b in the Y direction, and the position detection sensor 302X has a position detection sensor 302Y in the Y direction of the correction lens 203b. The position of the correction lens 203b in the X direction is detected in the same manner as the above.

Next, a mounting form of the high frequency sensors 5p and 5y and the low frequency sensors 6p and 6y will be described with reference to FIG.
FIG. 4A is a perspective view of the periphery of a fixed cylinder to which the high frequency sensors 5p and 5y and the low frequency sensors 6p and 6y are fixed. FIG.4 (b) is A view in FIG.4 (a).
The fixed cylinder 403 is a member whose rotational position around the Z axis does not change regardless of zooming or focus adjustment as long as the lens barrel is attached to the camera body. The cam groove 404 provided in the fixed barrel 403 is for moving the first lens group and the second lens group in the lens barrel.

First, the high-frequency sensor 5p is fixed to the fixed cylinder 403 via a mounting substrate 401 made of glass epoxy and a buffer member 406 made of an elastic member such as rubber, and is covered with a sound insulating cover 405p.
Specifically, the mounting substrate 401 is fixed to the mounting portion 403 a of the fixed cylinder 403 via the buffer member 406 with mounting screws 407, and the high frequency sensor 5 p is mounted on the mounting substrate 401. A cutout portion 401a is formed on the mounting substrate 401, and the high-frequency sensor 5p is covered with the sound insulation cover 405p by engaging the cutout portion 401a with the mounting projection 405a of the sound insulation cover 405p.

The high frequency sensor 5y is also mounted on the same mounting substrate 401 as the high frequency sensor 5p, and is covered with a sound insulation cover 405y.
Here, the buffer member 406 has a function of absorbing disturbance vibration that can superimpose noise on the output signals of the high-frequency sensors 5p and 5y and protecting the high-frequency sensors 5p and 5y. The sound insulation covers 405p and 405y also have a function of protecting the high frequency sensors 5p and 5y by absorbing disturbance vibrations.

  In particular, the buffer member 406 absorbs disturbance vibration that transmits a structural member in the camera system when a mechanism such as a quick return mirror or a shutter mechanism is operated. On the other hand, the sound insulation covers 405p and 405y absorb disturbance vibration (that is, sound) transmitted in the air. Incidentally, the frequency of these disturbance vibrations may cause noise because the high frequency sensors 5p and 5y are sensitive to a wide band of 30 Hz or more as shown in FIG. . Note that image blur may occur when the entire camera shakes as the quick return mirror stops or the shutter mechanism stops. The shake that causes the image blur also includes 30 Hz to 100 Hz. However, since the entire apparatus shakes, it can be detected without being absorbed by the buffer member 406, and the image blur when the tripod is mounted can be corrected with high accuracy.

A part of an analog circuit for processing output signals from the high frequency sensors 5p and 5y is also mounted on the mounting substrate 401 on which the high frequency sensors 5p and 5y are mounted. In order to increase the sound insulation effect, a member that absorbs vibration, such as urethane foam, may be interposed between the sound insulation covers 405p and 405y and the high frequency sensors 5p and 5y.
Next, the low frequency sensor 6p is fixed to the fixed cylinder 403 via a mounting substrate 402 made of a flexible printed circuit board. The low frequency sensor 6p is not covered by the sound insulation cover and may remain bare.

Specifically, a mounting substrate 402 is affixed to the mounting flat portion 403b provided on the surface of the fixed cylinder 403 by a double-sided tape, and the low frequency sensor 6p is mounted on the affixing surface of the mounting substrate 402. ing.
The low frequency sensor 6y is also mounted on the same mounting substrate 402 as the low frequency sensor 6p, and is fixed in the same manner as the low frequency sensor 6p. The low frequency sensor 6y is not covered with the sound insulation cover, and may be left exposed.

A part of an analog circuit for processing output signals from the two low frequency sensors 6p and 6y is also mounted on the mounting substrate 402 on which the low frequency sensors 6p and 6y are mounted.
Next, an image blur correction circuit of the camera system will be described with reference to FIG. FIG. 5 shows only a block diagram of the image blur correction circuit in the Y direction. There are two image blur correction circuits in this camera system: a Y-direction image blur correction circuit and an X-direction image blur correction circuit, but only the sensors and actuators used are different. The circuit configuration is the same. Therefore, only the former will be described here.

  As shown in FIG. 5, the image blur correction circuit in the Y direction includes a high-frequency sensor 5p, a low-frequency sensor 6p, amplifiers 501, 601, adders 502, 602, A / D converters 503, 603, and D / A conversion. 504, 604, MPU 500, motor driver 703, actuator 301Y, correction lens driving mechanism 704, position detection sensor 302Y, and A / D converter 705. Among these, the high frequency sensor 5p, the low frequency sensor 6p, the amplifiers 501, 601, the actuator 301Y, the correction lens driving mechanism 704, and the position detection sensor 302Y are mounted on the lens barrel as described above, and other circuits. Is mounted on the lens barrel or the camera body. However, since the characteristics of this circuit are adapted to the specifications of the photographing optical system in the lens barrel, it is preferable that the circuit is mounted on the lens barrel side rather than on the camera body side.

Now, when an angular shake in the pitch direction occurs in the camera system, angular velocity signals are output from the high frequency sensor 5p and the low frequency sensor 6p.
First, the angular velocity signal from the high frequency sensor 5p is amplified by the amplifier 501 with a predetermined gain. The amplifier 501 is also provided with a low-pass filter function, and the cutoff frequency of the amplifier 501 is the upper limit of the detection band of the high-frequency sensor 5p so that ultra-high frequency electrical noise (see FIG. 2) is removed. An appropriate value in the vicinity of the value (110 Hz) is set.

  Further, the adder 502 adds a DC signal to the angular velocity signal output from the amplifier 501. The value of the DC signal is sequentially calculated by the addition output calculation unit 505 in the MPU 500, and is a correction value for adapting the amplitude of the angular velocity signal to the dynamic range of the A / D converter 503 (this The correction value can take both positive and negative values.) The correction value calculated by the addition output calculation unit 505 is input to the adder 502 via the D / A converter 504.

The angular velocity signal having an appropriate amplitude in this way is converted into a digital signal by the A / D converter 503 and taken into the MPU 500.
The angular velocity signal captured by the MPU 500 passes through a high pass filter including a low pass filter (LPF) 506 having a cutoff frequency of about 0.1 Hz and a subtractor 507. In this high pass filter, the angular velocity signal is branched, one of which is input to the subtracter 507 via the low pass filter 506 and the other is input to the subtractor 507 as it is. According to such a high-pass filter, a very low frequency DC component (drift component) is removed from the angular velocity signal. The angular velocity signal after removal is input to the signal switching unit 711 in the MPU 500. Hereinafter, this angular velocity signal obtained from the high frequency sensor 5p is referred to as a high frequency signal.

  On the other hand, the angular velocity signal from the low frequency sensor 6p is amplified by the amplifier 601 with a predetermined gain. The amplifier 601 is also provided with a low-pass filter function, and its cutoff frequency is set to an appropriate value in the vicinity of 30 Hz so that noise (see FIG. 2) due to disturbance vibration is removed. This is why it is not necessary to protect the low frequency sensor 6p with a buffer member or a sound insulation cover. In addition, according to this low-pass filter function, ultra-high frequency electrical noise (see FIG. 2) is also removed at the same time.

  Further, the adder 602 adds a DC signal to the angular velocity signal output from the amplifier 601. The value of the DC signal is sequentially calculated by the addition output calculation unit 605 in the MPU 500, and is a correction value for adapting the amplitude of the angular velocity signal to the dynamic range of the A / D converter 603 (this The correction value can take both positive and negative values.) The correction value calculated by the addition output calculation unit 605 is input to the adder 602 via the D / A converter 604.

The angular velocity signal having an appropriate amplitude in this way is converted into a digital signal by the A / D converter 603 and taken into the MPU 500.
The angular velocity signal captured by the MPU 500 passes through a high-pass filter including a low-pass filter (LPF) 606 having a cutoff frequency of about 0.1 Hz and a subtractor 607. In this high-pass filter, the angular velocity signal is branched, one of which is input to the subtractor 607 via the low-pass filter 606 and the other is input to the subtractor 607 as it is. According to such a high-pass filter, a very low frequency DC component (drift component) is removed from the angular velocity signal. The removed angular velocity signal is input to the determination unit 710 and the signal switching unit 711 in the MPU 500. Hereinafter, this angular velocity signal obtained from the low frequency sensor 6p is referred to as a low frequency signal.

  The signal switching unit 711 outputs only one of the high frequency signal and the low frequency signal. Which signal is output is determined by the determination unit 710 in the MPU 500. The determination unit 710 compares the amplitude of the high-frequency signal with the amplitude of the low-frequency signal, and causes the signal switching unit 711 to output the signal having the larger amplitude. That is, it is determined which of the high frequency (20 Hz to 110 Hz) angular fluctuation applied in the pitch direction and the low frequency (1 Hz to 30 Hz) angular fluctuation is dominant, and the dominant angular fluctuation signal is determined. Is reflected in the image blur correction in the Y direction.

  The signal (low frequency signal or high frequency signal) is input to the target position calculation unit 701 in the MPU 500. The target position calculation unit 701 integrates the signal to calculate the tilt angle in the pitch direction of the camera system, and calculates the tilt angle and the image plane moving magnification of the photographing optical system (from the focal length and subject distance of the photographing optical system). The target position in the Y direction of the correction lens 203b is calculated. The target position in the Y direction is a position for canceling image blurring that occurs in the Y direction under the tilt angle.

Note that the focal length and subject distance of the photographic optical system are obtained from the positional relationship in the Z direction of the lens group in the lens barrel, and the information is always obtained by the lens CPU via the encoder in the lens barrel. Assume that it is grasped and sent to the MPU 500.
The calculated target position in the Y direction is input to the control unit 702 in the MPU 500. The control unit 702 includes, for example, a PID (Proportional, Integral, Dfferential) controller and the like, generates a control signal according to the target position, and provides it to the motor driver 703. The motor driver 703 performs, for example, PWM (Plus Width Modulation) drive on the actuator 301Y.

  The actuator 301Y drives the correction lens driving mechanism 704 according to the given driving amount, and moves the correction lens 203b in the Y direction. As a result, the subject image on the imaging surface moves in the Y direction. The movement amount is a value obtained by multiplying the actual movement amount of the correction lens 203b by the image plane movement magnification of the photographing optical system. In FIG. 5, the correction lens 203b is represented by an amplifier symbol.

Further, the position of the correction lens 203b in the Y direction is detected by the position detection sensor 302Y. The detection signal is converted into a digital signal by the A / D converter 705 and then input to the subtractor 706 inserted between the target position calculation unit 701 and the control unit 702.
The subtractor 706 obtains a deviation between the Y-direction target position calculated by the target position calculation unit 701 and the Y-direction position detected by the position detection sensor 302Y and supplies the deviation to the control unit 702. The control signal generated by the control unit 702 is a signal for reducing the deviation.

  The control system including the target position calculation unit 701, the subtractor 706, the control unit 702, the motor driver 703, the actuator 301Y, the correction lens driving mechanism 704, the position detection sensor 302Y, and the A / D converter 705 is the same as the correction lens 203b. Feedback control is performed to bring the position in the Y direction closer to the target position. Thus, image blur correction in the Y direction is achieved. The image blur correction circuit in the X direction also operates in the same manner as the above circuit.

Here, according to the determination unit 710 described above, the image shake correction reflects the low-frequency (1 Hz to 30 Hz) angular shake applied to the camera system and the high-frequency (20 Hz to 110 Hz) angular shake. , Become more dominant.
Therefore, in this camera system, under shooting conditions where camera shake (low frequency angular shake) is dominant, image shake due to the camera shake is actively suppressed, and mechanical vibration (high frequency angular shake) is suppressed. Under the dominant photographing situation, image blur due to the mechanical vibration is positively suppressed. In other words, the type of image blur to be suppressed is automatically and appropriately switched according to the shooting situation.

Moreover, in this camera system, since the switching of the suppression target is performed independently in the X direction and the Y direction, even if the type of angular shake that becomes dominant between the X direction and the Y direction is different, Appropriate image blur correction is performed in each direction.
Hereinafter, examples of shooting conditions of the camera system and suppression targets at that time will be listed.
-Hand-held shooting on a non-moving object: Since camera shake is dominant, image shake due to camera shake is a target to be suppressed.
Tripod photography on a non-moving object: Since mechanical vibration is dominant, image blur due to mechanical vibration is a target to be suppressed.
-Hand-held shooting on a moving object: Image blur caused by the dominant one of camera shake and mechanical vibration is a suppression target.
Tripod photography on a moving body: Since mechanical vibration is dominant, image blur due to mechanical vibration is a target to be suppressed.

(Modification)
Note that the image blur correction circuit of the camera system includes the determination unit 710. Instead of the determination unit 710, a switch that can be operated by the user is provided at any location (for example, the lens barrel side) of the camera system. And an output signal of the changeover switch may be input to the signal switching unit 711. An example of the circuit configuration in this case is shown in FIG. When this configuration is employed, the user may switch the suppression target by operating the changeover switch as necessary.

In that case, the change-over switch may be two systems of a change-over switch for switching the suppression target in the X direction and a change-over switch for switching the suppression target in the Y direction. Therefore, it is possible to use one system of changeover switches for switching the suppression target in the X direction and the suppression target in the Y direction together.
Instead of providing a dedicated changeover switch, similar switching may be performed using an operation member (a setting dial, a release button, etc.) provided in advance in the camera body.

  Further, instead of the changeover switch, a sensor for detecting a photographing state may be provided in any part of the camera system, and an output signal of the sensor may be input to the signal switching unit 711. An example of the sensor that detects the shooting situation is a sensor that detects whether the camera system is fixed to a fixing member such as a tripod. When the sensor is employed, the signal switching unit 711 may be operated so that a high frequency signal is output when the sensor is fixed and a low frequency signal is output when the sensor is not fixed.

[Second Embodiment]
The second embodiment of the present invention will be described below with reference to the drawings. This embodiment is an embodiment of a camera system. Here, only differences from the first embodiment will be described. The difference is in the configuration of the image blur correction circuit.
FIG. 7 is a block diagram of an image blur correction circuit (image blur correction circuit in the Y direction) according to the present embodiment. The image blur correction circuit of this camera system also has two systems, a circuit for correcting image blur in the Y direction and a circuit for correcting image blur in the X direction. The circuit configuration is the same except for the sensors and actuators. Accordingly, only a circuit for correcting image blur in the Y direction will be described here.

As shown in FIG. 7, the image blur correction circuit in the Y direction includes a high-frequency sensor 5p, a low-frequency sensor 6p, amplifiers 501 'and 601', an adder 602, an A / D converter 503, and a D / A converter. 504, MPU500, motor driver 703, actuator 301Y, correction lens drive mechanism 704, position detection sensor 302Y, and A / D converter 705.
First, the angular velocity signal output from the high frequency sensor 5p is limited to a predetermined frequency band by an amplifier 501 ′ having a function of a band pass filter. On the other hand, the angular velocity signal output from the low-frequency sensor 6p is limited to a frequency band equal to or lower than a predetermined value by an amplifier 601 ′ having a low-pass filter function. The filter characteristics and gains of these amplifiers 501 ′ and 601 ′ will be described later.

The two angular velocity signals after the limitation are added by the adder 602 and integrated into one angular velocity signal. Hereinafter, the integrated angular velocity signal is referred to as an addition signal.
The addition signal is subjected to the same amplitude correction and high-pass filter processing as in the first embodiment by a circuit comprising an adder 502, a D / A converter 504, an addition output calculation unit 505, a low-pass filter 506, and a subtractor 507. Applied. The processed addition signal is a control system including a target position calculation unit 701, a subtractor 706, a control unit 702, a motor driver 703, an actuator 301Y, a correction lens driving mechanism 704, a position detection sensor 302Y, and an A / D converter 705. Is input. This control system performs image blur correction in the Y direction by the same control as in the first embodiment. The image blur correction circuit in the X direction also operates in the same manner as the above circuit.

Here, according to the adder 602 described above, what is reflected in the image shake correction is the sum of the low-frequency angular shake applied to the camera system and the high-frequency angular shake.
Therefore, this camera system can simultaneously suppress both image blur caused by camera shake (low frequency angular shake) and image shake caused by mechanical vibration (high frequency angular shake).

However, in this camera system, it is necessary to set the filter characteristics and gains of the amplifiers 501 ′ and 601 ′ as follows in order to prevent the amplitude of the addition signal described above from becoming an abnormal value.
Next, filter characteristics and gains of the amplifiers 501 ′ and 601 ′ will be described with reference to FIG. In FIG. 8, the horizontal axis represents frequency [Hz] and the vertical axis represents gain [dB].

  The pass band of the filter characteristic of the amplifier 501 ′ is set to cover at least the frequency band of mechanical vibration (30 Hz to 50 Hz, preferably 30 Hz to 100 Hz), and the pass band of the filter characteristic of the amplifier 601 ′ is at least It is set so as to cover the frequency band of camera shake (3 Hz to 8 Hz, preferably 1 Hz to 10 Hz). Further, the cutoff frequency on the upper limit side of the amplifier 501 'is set to an appropriate value in the vicinity of 110 Hz so that ultra-high frequency electrical noise is removed.

The cutoff frequency f2 of the amplifier 601 ′ and the cutoff frequency f1 on the lower limit side of the amplifier 501 ′ satisfy the relationship f2 <f1, and the characteristic curve of the amplifier 601 ′ and the characteristic curve of the amplifier 501 ′ are: They are either completely separated or moderately overlap as shown in FIG.
If the overlap between both curves is too large, the amplitude of the added signal becomes a large abnormal value when an angular shake of the frequency belonging to the boundary (f2 to f1) occurs, and the image shake correction is overcorrected. That is, abnormal image blur may occur.

On the other hand, if the gap between the two curves is too large, the amplitude of the added signal becomes a small abnormal value when the angular shake of the frequency belonging to the boundary (f2 to f1) occurs, and the image blur correction is insufficient. There is a possibility that the vibration remains (the problem is that the overlap is too large rather than the gap is too large).
Therefore, according to the above setting, it is possible to suppress the possibility that the added signal becomes an abnormal value and to stabilize the image blur correction.

Further, the gain of the amplifier 501 ′ and the gain of the amplifier 601 ′ are set so as to cancel out the difference between the sensitivity of the high-frequency sensor unit and the sensitivity of the low-frequency sensor unit. This relationship is such that the sensitivity of the system including the high-frequency sensor 5p and the amplifier 501 ′ in FIG. 7 is matched with the sensitivity of the system including the low-frequency sensor 6p and the amplifier 601 ′.
Therefore, according to the above setting, it is possible to appropriately perform both the image blur correction due to the camera shake and the image blur correction due to the mechanical vibration.

In FIG. 8, the gain of the amplifier 501 ′ is expressed larger than the gain of the amplifier 601 ′. This is an example in which the sensitivity of the high frequency sensor alone is lower than the sensitivity of the low frequency sensor alone. When the sensitivity magnitude relationship is reversed, the gain magnitude relationship is also reversed.
(Modification)
Note that the image shake correction circuit of this camera system integrates (adds) two angular velocity signals in the analog domain, but integrates (adds) them in the digital domain (within the MPU 500) as shown in FIG. May be. In FIG. 9, an adder that integrates (adds) two angular velocity signals is indicated by reference numeral 511 in the MPU 500. In this case, the stage preceding the adder 511 is two systems of a high-frequency signal circuit and the low-frequency signal circuit, and the stage subsequent to the adder 511 is one system of an addition signal circuit.

  In addition, the image shake correction circuit of this camera system integrates (adds) the angular velocity signals, but obtains the target position individually from the two angular velocity signals and integrates (adds) the target positions. Also good. Alternatively, the tilt angles may be calculated individually from the two angular velocity signals, and the tilt angles may be integrated (added). In any case, there are two systems, a high-frequency signal circuit and a low-frequency signal circuit, before the integration point (addition point), and the subsequent stage from the integration point (addition point) is for the addition signal. It becomes one system of the circuit.

  In the image blur correction circuit of the camera system, as shown in FIG. 8, the boundary portions (f2 to f1) of the detection bands of the high frequency signal and the low frequency signal are the frequency band of the camera shake and the frequency band of the mechanical vibration. However, it may be set within the frequency band of camera shake or within the frequency band of mechanical vibration. However, it is desirable that the boundary portions (f2 to f1) be set to a band in which the angle fluctuation is less likely to occur compared to other bands (a band having a small amplitude even if it occurs).

[Others]
In each of the embodiments described above, a digital circuit (MPU) is used as the image blur correction circuit. However, part or all of the operation of the digital circuit may be realized by an analog circuit. Further, a part of the operation of the analog circuit of each embodiment described above may be realized by a digital circuit.

In each of the above-described embodiments, the camera system that drives the correction lens for image blur correction has been described. However, the present invention can also be applied to a camera system that drives an imaging unit (an imaging device or a film).
In each of the above-described embodiments, a camera system including a camera body and a lens barrel that can be attached to and detached from the camera body has been described. However, the present invention is also applied to a camera system in which the camera body and the lens barrel are integrated. The invention is applicable. Further, the present invention can be applied to an optical apparatus such as a video camera system, a field scope, and binoculars in addition to a still camera system.

1 is an overall configuration diagram of a camera system. It is a figure which shows the concept of the detection zone | band of low frequency sensor 6p, 6y and high frequency sensor 5p, 5y. 3 is a cross-sectional view of an image blur correction unit 3. FIG. It is a perspective view of the periphery of the fixed cylinder which fixed high frequency sensors 5p and 5y and low frequency sensors 6p and 6y. FIG. 3 is a block diagram of an image blur correction circuit (an image blur correction circuit in the Y direction) according to the first embodiment. It is a figure which shows the modification of 1st Embodiment. It is a block diagram of an image blur correction circuit (image blur correction circuit in the Y direction) of the second embodiment. It is a figure explaining the filter characteristic of amplifier 501 ', 601'. It is a figure which shows the modification of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Camera body, 2 ... Lens barrel, 201-204 ... Lens group, 3 ... Image blur correction unit, 5p, 5y ... High frequency sensor, 6p, 6y ... Low frequency sensor, 301X, 301Y ... Actuator, 302X, 302Y ... Position detection sensor

Claims (12)

A first sensor that detects vibrations applied to a photographing system that forms a photographed image;
A second sensor capable of detecting the vibration having a higher frequency than the first sensor;
An image shake correction apparatus comprising: a control unit that controls shake of the photographed image due to the vibration based on an addition value of detection results of the first sensor and the second sensor. The image blur correction device according to claim 1,
Low-pass filter means for performing low-pass filter processing on the output signal of the first sensor before the addition;
High-pass filter means for applying high-pass filter processing to the output signal of the second sensor before the addition,
The image blur correction device according to claim 1, wherein a cutoff frequency of the low-pass filter means is lower than a cutoff frequency of the high-pass filter means. The image blur correction apparatus according to claim 1 or 2, wherein
The controller is
An image blur correction apparatus that performs the addition using an analog signal. The image blur correction apparatus according to claim 1 or 2, wherein
The controller is
An image blur correction apparatus characterized by performing the addition using a digital signal. An image blur correction apparatus according to any one of claims 1 to 4, wherein
The first sensor is capable of detecting vibrations of 3 Hz to 8 Hz. An image blur correction apparatus according to any one of claims 1 to 5,
The first sensor is a vibration gyro using a single crystal as a vibrator,
The image blur correction device, wherein the second sensor is a vibration gyro using ceramic as a vibrator. The image blur correction device according to claim 6,
The first sensor uses crystal as a vibrator. An image blur correction device characterized in that: The image blur correction apparatus according to any one of claims 1 to 7,
The imaging system includes an amplification type solid-state imaging device. The image blur correction device according to any one of claims 1 to 8,
An image blur correction apparatus comprising a buffer member that supports the second sensor and absorbs disturbance. An optical apparatus comprising the image blur correction apparatus according to claim 1. An interchangeable lens comprising the image blur correction device according to any one of claims 1 to 9. A camera system comprising the image blur correction device according to claim 1.

Images