JP2009265181A - Image blur correcting device and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image blur correcting device which sequentially corrects image blur precisely in relation to ever-changing blur, which has various velocity components. <P>SOLUTION: A blur correction control means 6 which moves a correction means in the direction orthogonal to an optical axis by a step motor 111 and mitigates image degradation due to blur has speed control means 103, 104 which drive the step motor based on the blur speed by the output of a blur detection means 101, position control means 105-108 which drive the step motor based on the blur displacement by the output of the blur detection means, and a switch means 109 which switches the speed control means and the position control means corresponding to the blur frequency during image blur correction and drives the step motor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image shake correction apparatus and an image pickup apparatus that correct image blur caused by shake applied to an image pickup apparatus or the like by displacing a correction unit.

  In recent years, there has been an increasing demand for an image pickup apparatus that enables high-quality shooting with an image shake correction apparatus that optically corrects an image shake due to a shake such as a camera shake. In an image shake correction apparatus for an image pickup apparatus, an optical element (correction lens or image pickup element) is moved (displaced) in a plane orthogonal to the optical axis in accordance with a signal from a shake sensor such as a gyro sensor. Some devices suppress image blur on the image plane. Japanese Patent Application Laid-Open No. 2004-133867 discloses an imaging apparatus that performs image blur correction using a step motor as a drive source for driving an optical element. In the image blur correction apparatus using the step motor, it is not necessary to detect the position in the plane orthogonal to the optical axis of the optical element by using the position sensor, and therefore image blur correction by open loop control is possible.

  Since the step motor can accurately determine the position by the step operation, it is possible to perform image blur correction by position control as disclosed in Patent Document 1. That is, by comparing the integrated value of the shake obtained from the output of the shake sensor and the count number of drive pulses of the step motor, and controlling the drive direction of the step motor and the drive pulse interval, the optical direction is canceled out. The image blur is corrected by positioning the element.

Further, since the step motor rotates at a rotational speed synchronized with the input drive pulse interval (drive frequency), it is possible to perform image blur correction by speed control. That is, by controlling the rotation speed of the step motor according to the shake speed that is sequentially updated by the output of the shake sensor, the optical element is moved at a speed that cancels the shake to correct the image shake.
Japanese Patent Laid-Open No. 2006-129597

  In the above-described position control, it is possible to obtain a good image blur correction performance for a relatively low frequency shake. However, there has been a problem that a sufficient image blur correction performance cannot be obtained for a relatively high frequency blur. In step motor control, acceleration / deceleration control is performed so as to gradually accelerate and decelerate to prevent step-out. In position control, there is a possibility that the driving direction is frequently reversed with respect to high-frequency vibration, and a follow-up delay due to acceleration / deceleration control occurs every time, and sufficient vibration correction performance is obtained for relatively high-frequency vibration. There was a problem that it was not possible.

  On the other hand, in the speed control, it is possible to obtain a better image blur correction performance for a relatively high frequency blur as compared with the position control. This is because the shake speed changes continuously, so the speed of the step motor according to the shake speed also changes smoothly and is not easily limited by acceleration / deceleration control. However, in speed control, since the minimum control speed is limited, there is a problem that sufficient image blur correction performance cannot be obtained for a relatively low frequency shake.

  The shake applied to the imaging apparatus includes shakes having various characteristics such as low frequency shake and high frequency shake. For example, low-speed large-amplitude shakes caused by fluctuations in the photographer's body, fluctuations in the hand or arm holding the imaging apparatus, and high-speed small-amplitude fluctuations caused by the shutter operation of the imaging apparatus itself. Further, since the shake state changes every moment, it is necessary to sequentially select an appropriate image shake correction control. For this reason, in the method in which the photographer switches the control mode such as shake correction only by position control or speed control, or position control or speed control as appropriate, image blur correction that is appropriate for each time changing shake is performed. There was a problem that could not be done.

  In addition, since a control delay occurs in the control system, the image blur correction is always performed with a delay from the actual blur, and the appropriate image blur correction cannot be performed successively for the shake that changes every moment. There was a problem.

(Object of invention)
SUMMARY OF THE INVENTION An object of the present invention is to provide an image shake correction apparatus and an image pickup apparatus that have various speed components and can sequentially perform high-precision image shake correction with respect to shake that changes every moment. .

In order to achieve the above object, the present invention provides shake detection means for detecting shake, and shake correction control for reducing image degradation caused by the shake by moving the correction means in a direction perpendicular to the optical axis by a step motor. In the image shake correction apparatus having the above-mentioned means, the shake correction control means
Speed control means for driving the step motor based on a shake speed generated by the output of the shake detection means, position control means for driving the step motor based on shake displacement generated by the output of the shake detection means, and image shake correction operation The image blur correction apparatus includes switching means for switching the speed control means and the position control means in accordance with the shake frequency and driving the step motor.

Similarly, in order to achieve the above object, the present invention provides a shake detection unit that detects shake and a shake correction that reduces the image deterioration caused by the shake by moving the correction unit in a direction orthogonal to the optical axis by a step motor. And an image blur correction apparatus having a control unit.
A shake prediction unit that sequentially predicts a subsequent shake from an output of the shake detection unit, a speed control unit that drives the step motor based on a predicted shake speed by the shake prediction unit, and a predicted shake displacement by the shake prediction unit. A position control means for driving the step motor based on the switching, and a switch for driving the step motor by switching the speed control means and the position control means based on an output from the shake prediction means during an image blur correction operation. And an image blur correction apparatus having the above-described means.

  Similarly, in order to achieve the above object, the present invention is an imaging apparatus including the image blur correction apparatus of the present invention.

  According to the present invention, it is possible to provide an image blur correction apparatus capable of sequentially performing high-accuracy image blur correction with respect to shake that has various velocity components and changes every moment.

  The best mode for carrying out the present invention is as shown in Examples 1 and 2 below.

  FIG. 1 is a configuration diagram illustrating an outline of an image blur correction device provided in an imaging apparatus which is an example of an optical apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a correction lens for correcting image blur, which is held by a member (not shown) so as to be movable (displaceable) in a plane orthogonal to the photographing optical axis. Reference numeral 2 denotes a first step motor, which supports the correction lens 1 so that it can be driven in the first direction. Reference numeral 3 denotes a second step motor, which supports the correction lens 1 so that it can be driven in a second direction orthogonal to the first direction. Reference numeral 4 denotes a first driver that drives the first step motor 2 in accordance with a drive pulse output from a CPU 6 described later. Reference numeral 5 denotes a second driver, which drives the second step motor 3 in accordance with a drive pulse output from a CPU 6 described later.

  Reference numeral 6 denotes a CPU which outputs drive pulses to the first driver 4 and the second driver 5 in accordance with shake signals output from a first gyro sensor 7 described later and a second gyro sensor 8 described later. Further, it is possible to control the first driver 4 and the second driver 5 so as to switch the applied voltage applied to the first step motor 2 and the second step motor 3.

  Reference numeral 7 denotes a first gyro sensor which is a shake sensor, and outputs the shake of the imaging device in the first direction to the CPU 6 as a shake signal. Reference numeral 8 denotes a second gyro sensor, which outputs the shake of the imaging device in the second direction to the CPU 6 as a shake signal. These sensors may be sensors that detect acceleration, and in that case, it is desirable to use them by converting them into velocity signals or displacement signals by integration.

  When a shake such as a hand shake occurs in the imaging apparatus, a drive pulse is output from the CPU 6 to the first driver 4 and / or the second driver 5 in accordance with a shake signal output from the first gyro sensor 7 or the second gyro sensor 8. The The first driver 4 and / or the second driver 5 switches the voltage applied to each phase of the first step motor 2 and / or the second step motor 3 in accordance with the drive pulse, and rotationally drives each step motor. As a result, the correction lens 1 is displaced in a plane orthogonal to the optical axis, and image blur on an imaging surface (not shown) is corrected.

  FIG. 2 is a block diagram showing a circuit configuration of the image blur correction apparatus shown in FIG. In the following description, one-way shake correction by a pair of gyro sensors and a step motor will be described, but the same applies to two-way shake correction.

  Reference numeral 101 denotes a gyro sensor, which detects a shake such as a shake applied to an image pickup apparatus which is an example of an optical apparatus, and outputs a shake angular velocity signal ω. This is the same as the gyro sensors 7 and 8 in FIG. A shake prediction circuit 102 predicts future shake based on the shake angular velocity signal ω output from the gyro sensor 101 and outputs a shake prediction signal F. As the shake prediction, a future shake angular velocity signal may be predicted based on a plurality of time-sequential shake angular velocity signals ω, or a future shake angular velocity may be predicted based on a frequency analysis result of the shake angular velocity signal for a predetermined time. The frequency may be predicted.

  Here, the basic concept of shake prediction will be described.

Now, the shake prediction circuit stores the shake angular velocity ω1 [rad / sec] at a certain time T1 [sec] and the shake angular velocity ω0 [rad / sec] at a time T0 [sec] just before dT1 from the time T1 in an internal memory. Suppose you remember it. At this time, the deflection angular velocity ω2 [rad / sec] at time T2 [sec] after dT2 from time T1 is obtained by linear interpolation.
ω2 = ω1 + (ω1-ω0) × T2 / T1 (1)
(1). That is, it is possible to predict the next shake angular velocity signal based on the previous shake angular velocity signal.

  Note that the angular velocity signal ω [rad / sec] output from the gyro sensor is processed at a predetermined sampling interval dT [sec], and a driving target described later is calculated. For example, a value of about 1 msec is used as the sampling interval. The above-described T1 and T2 may be set to the same value as the sampling interval T0, and prediction may be performed for each sampling. In this case, it is possible to predict a deflection angular velocity about 1 msec ahead.

  Further, using the above-described idea of linear interpolation, as described above, it is possible to predict the next shake frequency based on the frequency analysis result for the previous shake.

Reference numeral 103 denotes a first drive target calculation circuit, which calculates a drive target signal TG1 of the step motor 111 based on the shake angular velocity signal ω output from the gyro sensor 101. The drive target signal TG1 includes a drive direction and a drive pulse interval (drive frequency). Here, it is assumed that the shake angular velocity is ω [rad / sec], the step width of the step motor 111 is dX [mm], and the correction coefficient is K1 [rad / mm]. Then, the drive pulse interval Tp [sec] is Tp = K1 × dX / ω (2)
(2). A first drive pulse calculation circuit 104 outputs a drive pulse signal P1 based on the drive target signal TG1 output from the first drive target calculation circuit 103.

Reference numeral 105 denotes an integrator that outputs an integral signal ∫ω of the shake angular velocity signal ω output from the gyro sensor 101. The integral signal ∫ω can be regarded as the absolute value of the deflection angle from a certain origin. Reference numeral 106 denotes a second drive target calculation circuit, which is based on an integration signal ∫ω that is a deflection displacement output from the integrator 105 and a displacement of the step motor 111 that is output from a counter 108 described later, that is, a current position Xnow. The drive target signal TG2 of the step motor 111 is output. The drive target signal TG2 includes a drive direction and a drive pulse interval (drive frequency). Here, the absolute value of the deflection angular displacement obtained from the integral signal is Xvib [rad], the step width of the step motor 111 is dX [mm], the current position of the step motor is Xnow [mm], and the correction coefficient is K2 [rad / mm]. Then, the drive pulse interval Tp [sec] is Tp = K2 × dX / (Xvib−Xnow) (3)
(3) Reference numeral 107 denotes a second drive pulse calculation circuit which outputs a drive pulse signal P2 based on the drive target signal TG2 output from the second drive target calculation circuit 106.

  A counter 108 counts a drive pulse signal Pout output from a switching circuit 109 described later, and outputs a current position Xnow of the step motor 111. Reference numeral 109 denotes a switching circuit that switches between the driving pulse signals P1 and P2 and outputs the driving pulse signal Pout. At that time, switching is performed based on the predicted shake signal F. When the drive pulse signal P1 is selected, the step motor 111 is driven by the first drive target calculation circuit 103 and the first drive pulse calculation circuit 104, and image blur correction by speed control is performed. When the drive pulse signal P2 is selected, the step motor 111 is driven by the integrator 105, the second drive target calculation circuit 106, the second drive pulse calculation circuit 107, and the counter 108, and image blur correction by position control is performed. Is called.

  A driver 110 controls the energization of the step motor 111 based on the drive pulse signal Pout output from the switching circuit 109 to drive the step motor 111.

  The driving pulse signal calculation method includes a calculation method for resetting the pulse interval for each pulse and a calculation method for resetting the pulse interval for every predetermined control time.

  FIG. 3A is an explanatory diagram of a calculation method for resetting the pulse interval for each pulse. At a certain time S1, a pulse interval Tn is calculated from the shake signal, and a drive pulse signal corresponding to the drive direction is output to drive the step motor 111. At time S2 after the time Tn, the pulse interval Tn + 1 is calculated again from the shake signal, a drive pulse signal corresponding to the drive direction is output, and the step motor 111 is driven again. By sequentially changing the drive pulse interval in accordance with the shake signal, the step motor 111 is driven at a drive speed corresponding to the shake speed or the shake displacement, and image shake correction can be performed.

  FIG. 3B is an explanatory diagram of a calculation method for resetting the pulse interval every certain control time. At a certain time S1, the pulse interval Tn is calculated from the shake signal, and during a certain control time Ts, the drive pulse signal is continuously output according to the pulse interval Tn, and the step motor 111 is driven. At time S2 after the control time Ts, the pulse interval Tn + 1 is calculated from the shake signal, and during the control time Ts, the drive pulse signal is continuously output according to the pulse interval Tn + 1, and the step motor 111 is driven. . By changing the drive pulse interval for each control time in accordance with the shake signal, the step motor 111 is driven at a drive speed corresponding to the shake speed or shake displacement, and image shake correction can be performed.

  In the first embodiment, image blur correction can be performed regardless of the calculation method of the drive pulse signal, and thus either method may be adopted according to the design requirements.

  The step motor 111 may cause a step-out when the drive pulse interval suddenly increases or decreases or the drive pulse interval becomes shorter than a predetermined value. For this reason, the first drive pulse calculation circuit 104 or the second drive pulse calculation circuit 107 desirably performs acceleration / deceleration control. As an acceleration / deceleration control method, when a drive pulse interval smaller than a predetermined threshold is input, a drive pulse signal may be output by replacing the drive pulse interval in accordance with a previously stored acceleration / deceleration table. Alternatively, the drive pulse signal may be controlled from the past drive pulse history so that the acceleration of the step motor does not exceed a predetermined threshold.

  4 to 6 are diagrams illustrating the follow-up waveform to the shake by the image shake correction apparatus according to the first embodiment. In the first embodiment, image blur correction by position control is performed by the integrator 105, the second drive target calculation circuit 106, the second drive pulse calculation circuit 107, and the counter 108.

  FIG. 4A shows a follow-up waveform when a low-frequency shake is input for position control (frequency 5 Hz, amplitude ± 30 μm). It can be seen that for a relatively low frequency shake, the current position follows the target position of the step motor 111, the deviation remaining as a correction is suppressed to a low level, and the image blur correction performance is high.

  FIG. 4B shows a follow-up waveform when a high-frequency vibration is input to the position control (frequency 30 Hz, amplitude ± 30 μm). For a relatively high frequency fluctuation, overshoot control occurs and the deviation is very large. In position control, a drive target proportional to the difference between the target position and the current position is set. Therefore, when the target position and the current position cross, for example, as indicated by A in the figure, the drive target is rapidly reversed. . As described above, since the drive pulse calculation circuit performs acceleration / deceleration control in order to prevent step-out of the step motor 111, the step motor 111 cannot be reversed suddenly. Therefore, a delay for inversion occurs, and overshoot control tends to occur. As a countermeasure, the correction coefficient K2 described above is set to a small value, so that overcorrection can be prevented and overshoot control can be suppressed. However, since the followability to the shake is deteriorated, the image shake correction performance is deteriorated as a whole.

  Therefore, in the position control, good image blur correction performance is exhibited for low-frequency shake, but image blur correction performance tends to deteriorate for high-frequency shake.

  In the first embodiment, the first drive target calculation circuit 103 and the first drive pulse calculation circuit 104 enable image blur correction by speed control. Since the shake speed changes continuously, the drive speed of the step motor 111 controlled according to the shake speed also changes smoothly according to the shake speed. Therefore, overshoot control due to sudden reversal as seen in position control is unlikely to occur, and high image blur correction performance is exhibited.

  FIG. 5B shows a follow-up waveform when a high-frequency vibration is input to the speed control (frequency 30 Hz, amplitude ± 30 μm). It can be seen that the deviation is suppressed as compared with the case of the position control, and high image blur correction performance is exhibited.

  However, since the minimum speed for control is limited in the speed control, the image correction performance with respect to low-frequency shake is lowered. FIG. 5A shows a follow-up waveform when a low-frequency vibration is input to the speed control (frequency 5 Hz, amplitude ± 30 μm). In the case of low-speed shake such as portion A in the figure, the drive target is below the minimum control speed, so the step motor 111 is stopped and the deviation is large.

Of the drive pulse signal calculation methods described above, in the case of the drive pulse calculation method in which the pulse interval is reset every fixed control time (see FIG. 3B), the speed of one step drive within the control time is controlled. The lowest speed on the top. That is, the control time is Ts [sec], and the step width (minimum resolution) of the step motor 111 is dX [mm]. Then, the minimum speed Vmin [mm / sec] specified for control is Vmin = dX / Ts (4)
(4). In this case, when the drive target speed calculated from the shake speed falls below the minimum speed Vmin, the step motor 111 is not driven, and if the shake speed is maintained for a certain period of time, the remaining follow-up to the shake is accumulated and image shake correction is performed. Performance deteriorates.

  In the case of the driving pulse calculation method in which the pulse interval is reset every pulse (see FIG. 3A), the minimum speed can be lowered by increasing the pulse interval. However, since the time until the next pulse setting increases accordingly, if the shake state changes during that time, the shake cannot be followed and the image blur correction performance deteriorates.

  Therefore, in the speed control, good image blur correction performance is exhibited for high-frequency shake, but image blur correction performance tends to be deteriorated for low-frequency shake.

  In the first embodiment, the switching circuit 109 can drive the step motor 111 while sequentially switching between speed control and position control during image blur correction. For example, image blur correction is normally performed by speed control. When the drive target speed calculated based on the shake prediction signal (predicted angular velocity signal) is below the minimum speed Vmin of the speed control described above, switching to position control enables high frequency even for low frequency shake. It is possible to obtain good image blur correction performance even with respect to shake.

  Further, in the first embodiment, the speed control and the position control are switched by the switching circuit 109 in accordance with the shake prediction signal F. Since a control delay occurs in the control system, it is possible to obtain good shake correction performance by switching the control by the shake prediction signal F. For example, it is possible to obtain good shake correction performance by performing speed control when the predicted shake speed by the shake prediction circuit 102 exceeds a prescribed threshold value and performing position control when the predicted shake speed is lower than a prescribed threshold value. When the control delay can be reduced, the speed control and the position control may be switched according to the shake angular speed signal ω without using the shake prediction signal F.

  Further, the threshold value of the switching circuit 109 can be given hysteresis. That is, by changing the threshold value according to the currently selected control method, it is possible to stabilize the switching operation and perform highly accurate image blur correction.

  FIG. 6 shows a tracking waveform when the position control and the speed control are switched according to the minimum speed Vmin of the speed control.

  FIG. 6A shows a follow-up waveform when a low-frequency vibration is input (frequency 5 Hz, amplitude ± 30 μm). In a low-speed part such as part A in the figure, since the speed control is switched to the position control, the control can be performed without degrading the image blur correction performance. FIG. 6B shows a follow-up waveform when a high-frequency shake is input (frequency 30 Hz, amplitude ± 30 μm). In high-frequency shake where the rate of high-speed shake is high, image blur correction is mainly performed by speed control. Therefore, it is possible to maintain the same shake correction performance as when image blur correction is performed only by speed control.

  Therefore, according to the first embodiment, it is possible to provide an image blur correction apparatus that has various velocity components and can perform good image blur correction sequentially with respect to blur that changes every moment.

  Next, a second embodiment of the present invention will be described. Since the second embodiment of the present invention is different from the first embodiment only in the configuration of the CPU 6, the description of other parts is omitted.

  FIG. 7 is a block diagram illustrating a circuit configuration of the image shake correction apparatus according to the second embodiment. Reference numeral 201 denotes a gyro sensor that detects a shake such as a shake applied to an image pickup apparatus that is an example of an optical apparatus, and outputs a shake angular velocity signal ω. A shake prediction circuit 202 predicts a future shake based on the shake angular velocity signal ω output from the gyro sensor 201 and outputs a predicted shake angular velocity signal ω ′. A switching circuit 203 switches the output destination of the predicted shake angular velocity signal ω ′ based on the predicted shake angular velocity signal ω ′.

Reference numeral 204 denotes a first drive target calculation circuit, which calculates a drive target signal TG for a step motor 210, which will be described later, based on the predicted shake angular velocity signal ω ′ output from the switching circuit 203. The drive target signal TG includes a drive direction and a drive pulse interval (drive frequency). Here, the predicted deflection angular velocity is ω [rad / sec], the step width of the step motor 210 is dX [mm], and the correction coefficient is K1 [rad / mm]. Then, the drive pulse interval Tp [sec] is Tp = K1 × dX / ω (5)
(5).

  Reference numeral 205 denotes an integrator that outputs an integration signal ∫ω ′ of the predicted shake angular velocity signal ω ′ output from the switching circuit 203. The integral signal ∫ω ′ can be regarded as the absolute value of the predicted deflection angle from a certain origin.

Reference numeral 206 denotes a second drive target calculation circuit, which is based on an integration signal ∫ω ′ output from the integrator 205 and a current position Xnow of the step motor 210 output from a counter 208 described later. The signal TG is output. The drive target signal TG includes a drive direction and a drive pulse interval (drive frequency). Here, the absolute value of the predicted deflection angle obtained from the integral signal ∫ω ′ is Xvib [rad], the step width of the step motor 210 is dX [mm], the current position of the step motor 210 is Xnow [mm], and the correction coefficient is Let K2 [rad / mm]. Then, the drive pulse interval Tp [sec] is Tp = K2 × dX / (Xvib−Xnow) (6)
(6).

  A drive pulse calculation circuit 207 outputs a drive pulse signal Pout based on the drive target signal TG output from the first drive target calculation circuit 204 or the second drive target calculation circuit 206. As described in the first embodiment, the step motor 210 is prevented from being stepped out by performing acceleration / deceleration control. Reference numeral 208 denotes a counter that counts the drive pulse signal Pout output from the drive pulse calculation circuit 207 and outputs the current position Xnow of the step motor 210. Reference numeral 209 denotes a driver which controls energization of the step motor 210 based on the drive pulse signal Pout output from the drive pulse calculation circuit 207 to drive the step motor 210.

  In the second embodiment, it is possible to switch between speed control and position control by the switching circuit 203. That is, when the predicted shake angular velocity signal ω ′ exceeds the prescribed threshold value SH1, the predicted shake angular velocity signal ω ′ is output to the first drive target calculation circuit 204, and the first drive target calculation circuit 204 and the drive pulse calculation circuit are output. 207 enables image blur correction by speed control. In other cases, a predicted shake angular velocity signal ω ′ is output to an integrator 205 described later, and an image based on position control is obtained by the integrator 205, the second drive target calculation circuit 206, the drive pulse calculation circuit 207, and the counter 208. Shake correction is possible.

  Therefore, as in the first embodiment, the second embodiment also provides a shake correction apparatus that has various speed components and can sequentially perform good image shake correction with respect to shake that changes every moment. It becomes possible.

  Further, since speed control or position control is performed based on the predicted shake angular velocity signal ω ′, a delay due to the control can be reduced, and good shake correction can be sequentially performed with respect to the shake that changes every moment.

(Correspondence between the present invention and the embodiment)
The first gyro sensor 7, the second gyro sensor 8, and the gyro sensors 101 and 201 correspond to the shake detection unit that detects the shake of the present invention. The first step motor 2, the second step motor 3, and the step motors 111 and 210 correspond to the step motor of the present invention, and the correction lens 1 corresponds to the correction means of the present invention. Further, the CPU 6 corresponds to a shake correction control means for reducing the image deterioration caused by the shake by moving the correction means in the direction orthogonal to the optical axis by the step motor of the present invention. Further, the first drive target calculation circuit 103 and the first drive pulse calculation circuit 104, or the first drive target calculation circuit 204 and the drive pulse calculation circuit 207 are based on the shake speed by the output of the shake detection means of the present invention. This corresponds to speed control means for driving the step motor. Further, the integrator 105, the second drive target calculation circuit 106, the second drive pulse calculation circuit 107, and the counter 108, or the integrator 205, the second drive target calculation circuit 206, the drive pulse calculation circuit 207, and the counter 108 are This corresponds to the position control means of the invention. The position control means drives the step motor based on the shake displacement generated by the output of the shake detection means.

  The switching circuit 109 corresponds to switching means for driving the step motor by switching the speed control means and the position control means in accordance with the shake frequency during the image blur correction operation of the present invention. To do. Further, the shake prediction circuit 102 corresponds to a shake prediction unit that sequentially predicts subsequent shakes from the output of the shake detection unit according to the first and fourth aspects of the present invention.

  The switching means drives the step motor by the output of the speed control means if the predicted shake speed by the shake prediction means exceeds the specified threshold value, and outputs the position control means if it falls below the specified threshold value. To drive the step motor. Alternatively, the step motor is driven by the output of the speed control means until the speed controlled by the speed control means reaches the specified minimum speed, and when the speed is lower than the specified minimum speed, the step motor is driven by the output of the position control means. Drive.

  Further, the switching circuit 203 switches between the speed control means and the position control means based on the output from the shake prediction means during the image shake correction operation of the present invention as set forth in claim 4 to drive the step motor. Corresponds to means. The switching means drives the step motor by the output of the speed control means when the predicted runout speed exceeds a specified threshold value, and when the predicted swing speed falls below the specified threshold value, Drive.

  In each of the above-described embodiments, an example is shown in which image blur correction is performed by moving the correction lens in a direction orthogonal to the optical axis. However, the image sensor included in the imaging device is moved in a direction orthogonal to the optical axis. In this case, image blur correction may be performed. Moreover, although the example applied to the imaging device is shown, it can also be applied to optical devices such as a mobile phone.

1 is a configuration diagram illustrating an outline of an image blur correction apparatus according to each embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image shake correction apparatus according to Embodiment 1 of the present invention. It is explanatory drawing which shows the calculation method of the drive pulse signal of the image blur correction apparatus which concerns on Example 1 of this invention. It is explanatory drawing which shows a follow-up waveform when a shake is input with respect to the position control which concerns on Example 1 of this invention. It is explanatory drawing which shows a follow-up waveform when shake | fluctuation is input with respect to the speed control which concerns on Example 1 of this invention. It is explanatory drawing which shows a follow-up waveform at the time of shake being input into the image blur correction apparatus which concerns on Example 1 of this invention. It is a block diagram which shows the structure of the image blur correction apparatus which concerns on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Correction lens 2 1st step motor 3 2nd step motor 4 1st driver 5 2nd driver 6 CPU
7 first gyro sensor 8 second gyro sensor 101 gyro sensor 102 shake prediction circuit 103 first drive target calculation circuit 104 first drive pulse calculation circuit 105 integrator 106 second drive target calculation circuit 107 second drive pulse calculation circuit 108 counter 109 switching circuit 110 driver 111 step motor 201 gyro sensor 202 shake prediction circuit 203 switching circuit 204 first drive target calculation circuit 205 integrator 206 second drive target calculation circuit 207 drive pulse calculation circuit 208 counter 209 driver 210 step motor

Claims (6)

Shake detection means for detecting shake;
In an image shake correction apparatus having a shake correction control means that moves the correction means in a direction orthogonal to the optical axis by a step motor and reduces image deterioration due to the shake.
The shake correction control means includes
Speed control means for driving the step motor based on the shake speed by the output of the shake detection means;
Position control means for driving the step motor on the basis of shake displacement caused by the output of the shake detection means;
An image blur correction apparatus comprising: switching means for switching the speed control means and the position control means in accordance with the shake frequency and driving the step motor during an image blur correction operation. The shake correction control means further includes shake prediction means for sequentially predicting subsequent shake from the output of the shake detection means,
The switching means drives the step motor by the output of the speed control means when the predicted shake speed by the shake prediction means exceeds a prescribed threshold value, and when the predicted shake speed falls below the prescribed threshold value, The image blur correction apparatus according to claim 1, wherein the step motor is driven by an output of a position control unit.   The switching means drives the step motor by the output of the speed control means until the speed controlled by the speed control means reaches a specified minimum speed, and when the speed is lower than the specified minimum speed, The image blur correction apparatus according to claim 1, wherein the step motor is driven by an output of a control unit. Shake detection means for detecting shake;
In an image shake correction apparatus having a shake correction control means that moves the correction means in a direction orthogonal to the optical axis by a step motor and reduces image deterioration due to the shake.
The shake correction means includes
Shake prediction means for sequentially predicting subsequent shake from the output of the shake detection means;
Speed control means for driving the step motor based on the predicted shake speed by the shake prediction means;
Position control means for driving the step motor based on the predicted deflection displacement by the shake prediction means;
An image blur correction apparatus comprising: a switching unit that switches between the speed control unit and the position control unit and drives the step motor based on an output from the blur prediction unit during an image blur correction operation. .   The switching means drives the step motor by the output of the speed control means when the predicted runout speed exceeds a prescribed threshold value, and when the predicted shake speed falls below the prescribed threshold value, The image blur correction apparatus according to claim 4, wherein the step motor is driven by an output.   An image pickup apparatus comprising the image shake correction apparatus according to claim 1.

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