JP2013050592A - Vibration-proof actuator, lens unit provided therewith and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration-proof actuator capable of performing appropriate image shake correction in both cases where a still image is imaged and where a moving image is imaged.SOLUTION: A vibration-proof actuator 10 for correcting image shake in imaging of a moving image and a still image includes: a fixing section 12; a movable section 14 mounted with a lens for preventing image shake 16; movable section supporting means 18; driving means 20 and 22 for driving the movable section 14; imaging mode determining means 40 for determining whether an imaging mode is a moving image imaging mode or a still image imaging mode; a shake detecting sensor 34; controlling means 36 that controls the driving means 20 and 22 on the basis of shake detected and moves the movable section 14 such that an image to be imaged becomes stable; and maximum value limiting means 44 for, on the basis of the imaging mode determined by the imaging mode determining means 40, limiting a maximum value of a shake detection value that is detected by the shake detecting sensor 34 and is utilized for control of the driving means 20 and 22.

Description

  The present invention relates to an image stabilization actuator, and more particularly to an image stabilization actuator that moves an image stabilization lens disposed in a lens barrel in order to correct image shake in moving image shooting and still image shooting, and the same. It relates to a lens unit and a camera.

  Japanese Patent No. 4387028 (Patent Document 1) describes an imaging apparatus, an imaging method, and a computer-readable recording medium on which a program for causing a computer to execute the method is recorded. The imaging apparatus includes a camera shake detection unit that detects camera shake, and a still image correction amount calculation unit that calculates an image blur correction amount in a still image shooting mode based on the camera shake detected by the camera shake detection unit. And a moving image correction amount calculation means for calculating an image blur correction amount in the moving image shooting mode. These still image correction amount calculating means and moving image correction amount calculating means calculate the image blur correction amount in parallel, and when the still image shooting mode is selected, the still image correction amount calculating means calculates in parallel by the still image correction amount calculating means. When the moving image shooting mode is selected, the image blur is corrected based on the image blur correction amount calculated by the moving image correction amount calculator. .

  The camera shake detection means is configured to detect a rotation angular velocity due to camera shake, and the moving image correction amount calculation means rotates in a predetermined low frequency band out of the rotation angular velocities detected by the camera shake detection means. Filtering means for filtering the angular velocity is provided. Further, the moving image correction amount calculation means calculates the moving image correction amount based on the value obtained by integrating the rotational angular velocities filtered by the filtering means. In the imaging apparatus described in Japanese Patent No. 4387028, as described above, the rotational angular velocity in the low frequency band is filtered and removed, and the moving image correction amount is calculated based on the value obtained by integrating the filtered rotational angular velocity. Optimal and quick image blur correction is realized both when shooting still images and when shooting moving images.

Japanese Patent No. 4387028

  However, in the imaging device described in Japanese Patent No. 4387028, the rotational angular velocity in the low frequency band is filtered and removed, and the moving image correction amount is calculated based on the filtered value. There is a problem of doing. In addition, when a filtering operation for cutting the low frequency band is performed on the rotational angular velocity data detected by the camera shake detection means, there is a problem that a phase delay occurs in the rotational angular velocity signal due to the filtering operation. Furthermore, when performing the filtering calculation, there is a problem that the amount of calculation to be performed by software increases and the processing speed of image blur correction becomes slow. Alternatively, in order to increase the processing speed of image blur correction, a high-performance microprocessor is required, and there is a problem that the cost of the image blur correction apparatus (anti-vibration actuator) increases.

  On the other hand, if filtering for cutting the low frequency band is to be realized by an analog circuit, a separate low cut filter circuit is required, which increases the number of components and increases the cost. In addition, the filter using an analog circuit has a problem that an output voltage drifts due to a temperature change during use, and an accurate rotation angular velocity signal cannot be obtained.

  Therefore, the present invention provides a vibration-proof actuator capable of performing appropriate image blur correction both at the time of still image shooting and at the time of moving image shooting, while avoiding adverse effects such as phase delay due to computation and temperature drift due to the filtering circuit, And a lens unit and a camera including the same.

  In order to solve the above-described problems, the present invention provides an image stabilization actuator that moves an image blur prevention lens arranged in a lens barrel in order to correct image blur in moving image shooting and still image shooting. A fixed part, a movable part to which an image blur prevention lens is attached, a movable part supporting means for supporting the movable part movably with respect to the fixed part, and a driving force between the fixed part and the movable part. A driving mode that drives the movable part relative to the fixed part, and a shooting mode determination that determines whether the moving picture shooting mode for shooting a moving picture or the still picture shooting mode for shooting a still picture Means, a shake detection sensor for detecting the shake of the lens barrel, and a drive means based on the shake detected by the shake detection sensor to control the movement of the movable part so that the captured image is stabilized. And a maximum value limiting means for limiting the maximum value of the shake detection value detected by the shake detection sensor and used for controlling the drive means based on the shooting mode determined by the shooting mode determination means. It is characterized by.

  In the present invention configured as described above, the movable portion to which the image blur prevention lens is attached is supported by the movable portion support means so as to be movable with respect to the fixed portion. The control means controls the drive means based on the shake detected by the shake detection sensor that detects the shake of the lens barrel, and the drive means applies the drive force between the fixed part and the movable part to move the movable part. To drive. The shooting mode determination means determines whether the moving image shooting mode for shooting a moving image or the still image shooting mode for shooting a still image. The maximum value limiting means limits the maximum value of the shake detection value detected by the shake detection sensor and used for controlling the driving means based on the shooting mode determined by the shooting mode determination means, and performs imaging in each shooting mode. Appropriate shake correction is executed so that the image to be stabilized becomes stable.

  According to the present invention configured as described above, since the image is appropriately stabilized in each photographing mode only by the maximum value limiting means limiting the maximum value of the shake detection value, the phase delay due to the calculation and the filtering circuit Thus, it is possible to perform appropriate image blur correction both during still image shooting and during moving image shooting, while avoiding adverse effects such as temperature drift caused by.

  In the present invention, it is preferable that the maximum value limiting unit sets the maximum shake detection value lower than the maximum value in the still image shooting mode when the shooting mode determined by the shooting mode determination unit is the moving image shooting mode. Restrict.

  According to the present invention configured as described above, since the maximum value of the shake detection value in the moving image shooting mode is limited to be lower than the maximum value in the still image shooting mode, the shake correction amount becomes excessive at the time of moving image shooting. Therefore, it is possible to perform sufficient shake correction during still image shooting while suppressing unnatural shake of the moving image.

  In the present invention, preferably, the shake detection sensor is a sensor that detects a shake angular velocity, and the maximum value limiting means limits the maximum value of the shake angular speed used for controlling the drive means.

  According to the present invention configured as described above, effective shake correction can be performed both during moving image shooting and during still image shooting only by limiting the maximum detection value of the shake detection sensor.

  In addition, the present invention is a lens unit that is used by being attached to a camera body and has an image blur correction function in moving image shooting and still image shooting, and includes a lens barrel and an image pickup disposed in the lens barrel. Lens, a fixed part fixed to the lens barrel, an image blur prevention lens moved to correct image blur, a movable part to which the image blur prevention lens is attached, and the movable part A movable portion supporting means for supporting the movable portion relative to the fixed portion, a driving means for driving the movable portion relative to the fixed portion by applying a driving force between the fixed portion and the movable portion, and a camera body The shooting mode reading means for reading from the camera whether the setting is set to the movie shooting mode for shooting a movie or the still image shooting mode for shooting a still image, and this shooting mode reading A shooting mode determination means for determining whether the shooting mode read from the stage is a moving image shooting mode or a still image shooting mode, a shake detection sensor for detecting a shake of the lens barrel, and a detection by this shake detection sensor Detecting by the shake detection sensor based on the control unit that controls the driving unit based on the shake and moves the movable part so that the captured image is stabilized, and the shooting mode determined by the shooting mode determination unit And maximum value limiting means for limiting the maximum value of the shake detection value used for controlling the driving means.

  Furthermore, the present invention is a camera having an image shake correction function in moving image shooting and still image shooting, a camera body, a lens barrel, an imaging lens disposed in the lens barrel, a lens A fixed portion fixed to the lens barrel, an image blur prevention lens that is moved to correct image blur, a movable portion to which the image blur prevention lens is attached, and the movable portion. A movable portion supporting means that is movably supported with respect to the movable portion, a driving means that drives the movable portion relative to the fixed portion by applying a driving force between the fixed portion and the movable portion, and moving image shooting for shooting a moving image A shooting mode determination means for determining whether the mode or a still image shooting mode for shooting a still image, a shake detection sensor for detecting a shake of the lens barrel, and a shake detected by the shake detection sensor On the basis of the Control of the driving means by controlling the moving means to move the movable portion so that the captured image is stabilized and the shake detection sensor based on the shooting mode determined by the shooting mode determining means And a maximum value limiting means for limiting the maximum value of the shake detection value used in the above.

  According to the anti-vibration actuator of the present invention, and the lens unit and camera including the same, in both the still image shooting and the moving image shooting while avoiding adverse effects such as phase delay due to calculation and temperature drift due to the filtering circuit. Appropriate image blur correction can be performed.

It is sectional drawing of the camera by embodiment of this invention. It is side surface sectional drawing of the vibration proof actuator with which the camera by embodiment of this invention is equipped. It is a front view which shows the state which removed the movable part of the vibration proof actuator. It is a front view of the movable part of a vibration proof actuator. It is a block diagram which shows typically the signal processing in a controller. It is a flowchart which shows the procedure of shake correction control.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
A camera according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a camera according to an embodiment of the present invention.
As shown in FIG. 1, a camera 1 according to an embodiment of the present invention includes a lens unit 2 and a camera body 4. The lens unit 2 includes a lens barrel 6, a plurality of imaging lenses 8 disposed in the lens barrel, an image stabilization actuator 10 that moves the image blur prevention lens 16 within a predetermined plane, and a lens. Gyroscopes 34a and 34b (only 34a is shown in FIG. 1), which are shake detection sensors for detecting the shake angular velocity of the lens barrel 6, are provided.

  In the camera 1 according to the embodiment of the present invention, the angular velocity is detected by the gyros 34 a and 34 b, the image stabilization actuator 10 is operated based on the detected angular velocity, and the image blur prevention lens 16 is moved. The image focused on the image sensor 7 is stabilized. In addition, the camera 1 according to the present embodiment operates a mode switching switch 4a provided in the camera body 4 to operate a still image shooting mode for shooting a still image and a moving image shooting mode for shooting a movie. It can be switched. In the present embodiment, piezoelectric vibration gyros are used as the gyros 34a and 34b. In the present embodiment, the image blur prevention lens 16 is constituted by a single lens, but the lens for stabilizing the image may be a plurality of lens groups. In this specification, the image blur prevention lens includes one lens and a lens group for stabilizing an image.

The lens unit 2 is an interchangeable lens unit that is used by being attached to the camera body 4, and is configured to form an image of incident light on the image sensor 7.
The generally cylindrical lens barrel 6 holds a plurality of imaging lenses 8 therein, and allows focus adjustment by moving some imaging lenses 8.

  Next, the vibration-proof actuator 10 will be described with reference to FIGS. FIG. 2 is a side sectional view of the vibration-proof actuator 10. FIG. 3 is a front view showing a state in which the movable part of the vibration isolation actuator 10 is removed, and FIG. 4 is a front view of the movable part of the vibration isolation actuator 10. 2 is a cross-sectional view showing a state in which the vibration-proof actuator 10 is broken along the line II-II in FIG.

  As shown in FIGS. 2 to 4, the vibration-proof actuator 10 includes a fixed plate 12 that is a fixed portion fixed in the lens barrel 6, and a movable portion that is supported so as to translate relative to the fixed plate 12. And three steel balls 18 which are movable part supporting means for supporting the moving frame 14. Further, the vibration isolation actuator 10 is attached to the first driving coil 20a and the second driving coil 20b attached to the fixed plate 12, and the moving frame 14 at positions corresponding to the respective driving coils 20a and 20b. The first driving magnet 22a and the second driving magnet 22b, and the first magnetic sensor 24a and the second magnetic sensor 24b which are position sensors respectively disposed inside the driving coils 20a and 20b, Have

  Further, the vibration-proof actuator 10 includes two suction yokes 26 attached to the back side of the fixed plate 12 and the respective drive magnets so that the moving frame 14 is attracted to the fixed plate 12 by the magnetic force of each drive magnet. And a back yoke 28 attached to the opposite surface of each driving magnet so as to effectively direct the magnetic force toward the fixed plate 12. The first driving coil 20a, the second driving coil 20b, and the first driving magnet 22a and the second driving magnet 22b attached to the corresponding positions are respectively provided on the fixed plate 12 and the moving frame 14. A driving means is configured to drive the moving frame 14 with respect to the fixed plate 12 by applying a driving force therebetween.

  Further, as shown in FIG. 1, the vibration isolation actuator 10 includes a controller 36 that is a control means. The controller 36 feeds back the position detection signals detected by the first and second magnetic sensors 24a and 24b, and controls the driving means so that the shake detected by the gyros 34a and 34b is corrected, thereby moving the moving frame. 14 is moved. Further, the controller 36 includes a shooting mode reading means 38, a shooting mode determination means 40, and a maximum value limiting means 44 (referred to as FIG. 5 above), which are appropriate according to the shooting mode as will be described later. The image blur prevention control is executed. In the present embodiment, the controller 36 includes a microprocessor, a memory, a program (not shown) stored therein, and the like.

  The anti-vibration actuator 10 translates the moving frame 14 with respect to the fixed plate 12 fixed to the lens barrel 6 in a plane orthogonal to the optical axis, thereby preventing image blur attached to the moving frame 14. Even if the lens 16 is moved and the lens barrel 6 vibrates, the lens 16 is driven so that the image formed on the image sensor 7 is not disturbed.

  The fixed plate 12 has a generally donut plate shape, and the first and second drive coils 20a and 20b are disposed thereon. As shown in FIG. 3, the centers of these two driving coils are arranged on the circumference centering on the optical axis of the lens unit 2. In the present embodiment, the second drive coil 20b is disposed vertically above the optical axis, and the first drive coil 20a is disposed at a position perpendicular to the vertical. Accordingly, the first drive coil 20a and the second drive coil 20b are arranged so as to be perpendicular to each other.

  The first and second drive coils 20a and 20b are wound in a rectangular shape with rounded corners. The first and second drive coils 20a and 20b have the same substantially rectangular shape, and are arranged so that the center lines crossing the long sides thereof coincide with the horizontal axis and the vertical axis, respectively. That is, the first and second drive coils 20a and 20b are arranged so that their long sides are directed in the circumferential direction of a circle having the optical axis A as the center.

  The moving frame 14 has a generally donut plate shape, and is arranged in parallel with the fixed plate 12 so as to overlap the fixed plate 12. An image blur prevention lens 16 is attached to the central opening of the moving frame 14. In the moving frame 14, first and second driving magnets 22a and 22b are arranged at positions corresponding to the first and second driving coils 20a and 20b, respectively. The first and second drive magnets 22a and 22b have a generally rectangular shape, and are arranged so that the center lines crossing the long sides thereof coincide with the horizontal axis and the vertical axis, respectively. The first and second drive magnets 22a and 22b are magnetized so that the center line crossing the short side becomes the magnetization boundary line C. That is, both the first and second drive magnets 22a and 22b are arranged so that the magnetization boundary line C faces the circumferential direction of a circle having the optical axis A as the center.

  As shown in FIGS. 2 and 3, the three steel balls 18 are sandwiched between the fixed frame 12 and the moving frame 14, and each have a central angle of 120 ° on the circumference of a circle centered on the optical axis A. They are arranged at intervals. Each steel ball 18 is disposed in a recess 30 formed at a position corresponding to each steel ball 18 in the fixed frame 12, and is prevented from falling off. As will be described later, since the moving frame 14 is attracted to the fixed plate 12 by the driving magnet, each steel ball 18 is sandwiched between the fixed plate 12 and the moving frame 14. As a result, the moving frame 14 is supported on a plane parallel to the fixed plate 12, and each steel ball 18 is rolled while being sandwiched, thereby allowing translational movement of the moving frame 14 with respect to the fixed plate 12 in any direction.

  In this embodiment, a steel sphere is used as the steel ball 18, but the steel ball 18 is not necessarily a sphere. In other words, the steel ball 18 can be used as long as the portion in contact with the fixed plate 12 and the moving frame 14 has a substantially spherical shape during the operation of the vibration isolating actuator 10. In addition, in this specification, such a form is called a spherical body.

  The back yoke 28 has a substantially rectangular shape, and is attached to a position corresponding to each driving magnet on the surface of the moving frame 14 on which the driving magnet is not attached. By these back yokes 28, the magnetic flux of each driving magnet is efficiently directed toward the fixed plate 12.

  The suction yoke 26 has a substantially rectangular shape, and is attached to a position corresponding to each drive coil on the surface of the fixed plate 12 on which the drive coil is not attached. The moving frame 14 is attracted to the fixed plate 12 by the magnetic force exerted by each driving magnet on the attracting yoke 26.

  As shown in FIG. 2, the magnetization boundary line C of the second drive magnet 22b is positioned so as to pass through the midpoint of each short side of the rectangular second drive magnet 22b, and the second drive magnet 22b. The polarity also changes in the thickness direction. In the present embodiment, the lower left corner in FIG. 2 is the S pole, the lower right is the N pole, the upper left is the N pole, and the upper right is the S pole. The first drive magnet 22a is similarly magnetized, and the direction of attachment to the moving frame 14 is rotated by 90 ° with respect to the second drive magnet 22b (FIG. 4). In this specification, the magnetization boundary line C is a line connecting points where the polarity changes from the S pole in the middle to the N pole when both ends of the driving magnet are set to S pole and N pole, respectively. Say it.

  By being magnetized in this way, the first and second drive magnets 22a and 22b exert magnetism on the long sides of the rectangular first and second drive coils 20a and 20b. Thus, when a current flows through the first driving coil 20a, a horizontal driving force is generated between the first driving magnet 22a, and when a current flows through the second driving coil 20b, the vertical driving is performed. Force is generated.

As shown in FIGS. 2 and 3, a first magnetic sensor 24a and a second magnetic sensor 24b, which are position sensors, are arranged inside each driving coil. In the present embodiment, a Hall element is used as the magnetic sensor.
The output signal from the magnetic sensor is 0 when the sensitivity center point S of the magnetic sensor is located on the magnetization boundary line C of the drive magnet, and the drive magnet moves, and the sensitivity center point S of the magnetic sensor. Deviates from the magnetization boundary line C of the driving magnet, the output signal of the magnetic sensor changes. During normal operation of the vibration isolating actuator 10, the amount of movement of the driving magnet is very small, and the magnetic sensor outputs a signal that is substantially proportional to the moving distance in the direction orthogonal to the magnetization boundary line C of the driving magnet. To do.

  Therefore, the first magnetic sensor 24a outputs a signal substantially proportional to the translational movement amount of the horizontal movement frame 14, and the second magnetic sensor 24b outputs a signal substantially proportional to the translational movement amount of the vertical movement frame 14. Output. Based on the signals detected by the first and second magnetic sensors 24a and 24b, the displacement of the moving frame 14 relative to the fixed frame 12 can be detected.

  The gyros 34 a and 34 b are attached to the lens unit 2 and configured to detect the rotational angular velocity of the camera 1. The gyro 34a detects a rotational angular velocity (yaw angular velocity) centered on the Y axis in a plane orthogonal to the optical axis A, and the gyro 34b detects a rotational angular velocity (pitch angular velocity) centered on the X axis. Are arranged so that the rotational angular velocity in each direction can be detected. Angular velocity signals detected by the gyros 34 a and 34 b are input to the controller 36.

  The controller 36 is configured to control the image stabilization actuator 10 based on the detection signals from the gyros 34 a and 34 b to suppress the image shake formed on the image sensor 7. The controller 36 calculates a position where the image blur prevention lens 16 should be moved based on the signals input from the gyros 34a and 34b. Further, the controller 36 causes a current to flow through the first and second drive coils 20a and 20b, and moves the image blur prevention lens 16 toward the calculated position. The position of the moved image blur prevention lens 16 is detected by the first and second magnetic sensors 24 a and 24 b and fed back to the controller 36.

  The controller 36 may be configured to include an A / D converter that converts each detection signal into digital data, a D / A converter that converts digital data into an analog signal, and the like, or The controller 36 can also be configured to incorporate various arithmetic circuits, analog circuits such as filters, and the like.

  Next, control of the vibration isolating actuator 10 by the controller 36 will be described with reference to FIGS. FIG. 5 is a block diagram schematically showing signal processing in the controller 36. FIG. 6 is a flowchart showing a procedure of shake correction control.

  As shown in FIG. 5, the controller 36 includes a first A / D converter 42, a D / A converter 50, and a second A / D converter 52. Further, the controller 36 realizes a photographing mode reading unit 38, a photographing mode determining unit 40, a maximum value limiting unit 44, and an integrating unit 46 by calculation of a built-in microprocessor (not shown).

  First, the shooting mode reading means 38 reads the state of the mode changeover switch 4 a provided in the camera body 4. The shooting mode determination unit 40 determines whether the state of the mode switch 4a read by the shooting mode reading unit 38 is the moving image shooting mode or the still image shooting mode. On the other hand, detection signals from the gyros 34a and 34b are input to the first A / D converter 42, and the angular velocity signals detected by the gyros 34a and 34b are the numerical data x of the angular velocity in the x and y directions, which are shake detection values. Converted to ', y'. The maximum value of the converted angular velocity numerical data x ′ and y ′ is limited by the maximum value limiting means 44. The limitation of the maximum value by the maximum value limiting unit 44 is performed based on the moving image shooting mode or the still image shooting mode determined by the shooting mode determination unit 40. The limitation on the maximum value will be described later.

  The angular velocities x ′ and y ′ whose maximum values are limited by the maximum value limiting means 44 are integrated over time by the integrating means 46, and the deflection angles x and y (yaw angle and pitch angle) in the x and y directions are calculated. The

  On the other hand, detection signals from the first and second magnetic sensors 24 a and 24 b are converted into numerical data Sx and Sy by the second A / D converter 52. The detection signals from the first and second magnetic sensors 24 a and 24 b represent the movement distances of the image blur prevention lens 16 in the x and y directions, and are numerical data converted by the second A / D converter 52. Sx and Sy are converted into deflection angles in the x and y directions.

  Next, the numerical data Sx and Sy converted by the second A / D converter 52 are subtracted from the shake angles x and y calculated by the integrating means 46. The subtracted numerical data is input to the D / A converter 50, and a current proportional to the numerical data is supplied to the first and second driving coils 20a and 20b. When the image blur prevention lens 16 is moved to a horizontal position where the shake angle x calculated based on the output signal of the gyro 34a can be compensated, the shake angle x matches the numerical data Sx. These differences are zero, and no current flows through the first drive coil 20a. Similarly, when the image blur prevention lens 16 is moved to a vertical position where the shake angle y can be compensated, the shake angle y matches the numerical data Sy, and a current flows through the second drive coil 20b. Disappear.

  Next, a procedure for shake correction control will be described with reference to FIG. The flowchart shown in FIG. 6 is a subroutine that is repeatedly executed every predetermined time by the controller 36 during the operation of the camera 1.

  First, in step S1 of FIG. 6, it is determined whether or not the shake correction start flag is valid. The shake correction start flag is a flag whose value is changed based on the state of a start switch (not shown) of the camera shake correction function provided in the camera body 4, and the camera shake correction function is turned on. Is set to “valid”, and when it is turned off, it is set to “invalid”. If the shake correction start flag is valid, the process proceeds to step S2. If the shake correction start flag is invalid, the shake correction control is not executed, and thus one process of the flowchart of FIG. 6 is terminated.

  In step S <b> 2, angular velocity data x ′ and y ′ obtained by A / D converting the angular velocity signals detected by the gyros 34 a and 34 b are read from the first A / D converter 42.

  Next, in step S <b> 3, the shooting mode set in the camera body 4 by the mode switch 4 a is read from the camera body 4 by the shooting mode reading means 38 built in the controller 36.

  In step S4, the shooting mode determination means 40 built in the controller 36 determines whether the setting state of the mode switch 4a is the moving image shooting mode or the still image shooting mode. If it is in the moving image shooting mode, the process proceeds to step S5, and if it is in the still image shooting mode, the process proceeds to step S6.

  In step S5, the values of the angular velocity data x 'and y' are limited within a predetermined range by the maximum value limiting means 44 built in the controller 36. That is, when the angular velocity data x ′ is larger than the predetermined angular velocity maximum value ωxmax, the value of x ′ is replaced with ωxmax, and when the angular velocity data x ′ is smaller than the negative angular velocity maximum value −ωxmax. The value of x ′ is replaced with −ωxmax. Similarly, the value of the angular velocity data y ′ is also limited within the range of ± ωymax. In the present embodiment, the angular velocities in the horizontal direction and the vertical direction are each limited within a range of ± 1.35 deg / sec, and preferably the angular velocities are limited to ± 1.1 deg / sec to ± 1.6 deg / sec.

  Even when the maximum value is not limited by the maximum value limiting means 44, the detection capability of the gyros 34a and 34b and the limitation on signal processing in the controller 36 (for example, the first A / The maximum value of the angular velocity value exists due to the allowable input of the D converter 42). Therefore, limiting the maximum value by the maximum value limiting means 44 means limiting the maximum value of the angular velocity to a value lower than the maximum value of the angular velocity in the still image shooting mode. Preferably, the maximum value of angular velocity in the moving image shooting mode is limited to about 1/2 to 1/3 of the maximum value of angular velocity in the still image shooting mode.

  Next, in step S6, the angular velocity data x 'and y' are integrated by the integrating means 46, and the deflection angles x and y are calculated. When the moving image shooting mode is set, angular velocity data limited to a predetermined range is integrated in step S5.

  In step S7, the detection signals from the first and second magnetic sensors 24a and 24b are A / D converted by the second A / D converter 52, thereby converting the numerical data Sx into the deflection angles in the x and y directions. , Sy is calculated.

  Next, in step S8, the numerical data Sx and Sy calculated in step S7 are subtracted from the swing angles x and y calculated in step S6, and the current corresponding to the difference between them is the first and second drive coils. The moving frame 14 is driven by the flow through 20a and 20b.

  In step S9, it is determined again whether or not the shake correction start flag is valid. If the shake correction start flag is valid, the process returns to step S2 and the processes of steps S2 to S9 are repeated. When the camera shake correction function is turned off during the shake correction control in steps S2 to S9, the shake correction start flag is changed to “invalid”. In this case, the process proceeds to step S10.

  In step S10, a camera shake correction end process is executed, and one process in the flowchart of FIG. 6 ends. In the present embodiment, as the camera shake correction end process, first, the moving frame 14 is moved to a predetermined control center position. At this control center position, the optical axis of the image blur prevention lens 16 attached to the moving frame 14 and the optical axis of the other imaging lens 8 coincide. Next, the moving frame 14 is locked at the control center position by a locking mechanism (not shown) provided in the vibration isolation actuator 10.

  Next, the operation of the camera 1 according to the embodiment of the present invention will be described with reference to FIG. First, by turning on a start switch (not shown) for the camera shake prevention function of the camera 1, the vibration isolation actuator 10 provided in the lens unit 2 is operated. The gyros 34 a and 34 b attached to the lens unit 2 output angular velocity signals to the controller 36. The controller 36 moves the image blur prevention lens 16 momentarily so that the shake of the lens barrel 6 is corrected based on the angular velocity signal, and an image focused on the image sensor 7 of the camera body 4 is obtained. Stabilized.

  Further, when the mode selector switch 4a of the camera body 4 is set to the moving image shooting mode and a moving image is being shot, the maximum value of the angular velocity signal detected by the gyros 34a and 34b is limited by the maximum value limiting means 44. The For this reason, at the time of moving image shooting, the correction of the image with respect to the shake with a large angular velocity is peaked, and the shake correction by the vibration-proof actuator 10 is suppressed. During movie shooting, the photographer may intentionally move the camera 1 to follow the subject, and when the moving frame 14 is moved greatly to correct this shake, the moving frame 14 eventually becomes mechanically movable. It reaches the edge, and the video shot at this time is unnaturally shaken. In the camera 1 of the present embodiment, in the moving image shooting mode, since the shake correction by the anti-vibration actuator 10 is suppressed, the moving frame 14 rarely reaches the mechanical movable end, and the captured moving image is unnatural. The shake can be suppressed. In addition, in a moving image, it is difficult to recognize fine shake of each continuously captured image. Therefore, even if shake correction is suppressed, it is difficult to recognize a reduction in image quality.

  On the other hand, when the mode switch 4a of the camera body 4 is set to the still image shooting mode and a still image is shot, the maximum value limiting means 44 does not limit the maximum value of the angular velocity signal. For this reason, the shake correction function by the vibration-proof actuator 10 is utilized to the maximum, and the shake of the shot still image is sufficiently suppressed. In still image shooting, even if the maximum value of the angular velocity signal is not limited, the moving frame 14 rarely reaches the mechanical movable end due to the shake of the camera 1 that is not intended by the photographer. An image formed on one finder (not shown) is rarely shaken unnaturally.

  According to the camera 1 of the embodiment of the present invention, the image is appropriately stabilized in each photographing mode only by the maximum value limiting unit 44 limiting the maximum value of the angular velocity data x ′ and y ′. For this reason, while avoiding adverse effects such as phase lag caused by complex computation on the detection signal and temperature drift caused by adding a frequency selective filtering circuit, both during still image shooting and movie shooting Appropriate image blur correction can be performed.

  In addition, according to the camera 1 of the present embodiment, the maximum value of the angular velocity detection value in the moving image shooting mode is limited to be lower than the maximum value in the still image shooting mode. , It is possible to suppress unnatural shake of the captured moving image. That is, during video recording, the photographer intentionally moves the camera intentionally, and when the image stabilization actuator 10 is operated so as to correct the image shake due to such camera movement, the amount of movement of the moving frame 14 Becomes excessive, and the moving frame 14 reaches the mechanical movable end. In such a case, the shake correction suddenly stops at the movable end of the moving frame 14, and the captured moving image is unnaturally shaken greatly. In the camera 1 of the present embodiment, since shake correction is suppressed in the moving image shooting mode, occurrence of large shake due to excessive movement of the moving frame 14 can be suppressed. On the other hand, in the still image shooting mode, the maximum value of the angular velocity detection value is set larger than the maximum value in the still image shooting mode, so that the shake correction capability by the vibration isolation actuator 10 can be utilized to the maximum.

  As mentioned above, although preferable embodiment of this invention was described, a various change can be added to embodiment mentioned above. In particular, in the above-described embodiment, the present invention is applied to an interchangeable lens digital camera. However, the present invention can also be applied to a camera in which a lens unit and a camera body are integrated. In this case, the mode changeover switch for switching between the moving image shooting mode and the still image shooting mode can be provided on either the lens unit side or the camera body side.

DESCRIPTION OF SYMBOLS 1 Camera of embodiment of this invention 2 Lens unit 4 Camera main body 4a Mode changeover switch 6 Lens barrel 7 Imaging element 8 Imaging lens 10 Anti-vibration actuator 12 Fixing plate (fixing part)
14 Moving frame (movable part)
16 Image blur prevention lens 18 Steel ball (movable part support means)
20a First drive coil 20b Second drive coil 22a First drive magnet 22b Second drive magnet 24a First magnetic sensor (position sensor)
24b Second magnetic sensor (position sensor)
26 Suction yoke 28 Back yoke 30 Recess 34a, 34b Gyro (vibration detection sensor)
36 controller (control means)
38 shooting mode reading means 40 shooting mode determination means 42 first A / D converter 44 maximum value limiting means 46 integration means 50 D / A converter 52 second A / D converter

Claims (5)

An image stabilization actuator that moves an image blur prevention lens disposed in a lens barrel in order to correct image blur in moving image shooting and still image shooting,
A fixed part;
A movable part to which the lens for preventing image blur is attached;
Movable part support means for supporting the movable part movably with respect to the fixed part;
Driving means for applying a driving force between the fixed portion and the movable portion to drive the movable portion with respect to the fixed portion;
A shooting mode determining means for determining whether a moving image shooting mode for shooting a moving image or a still image shooting mode for shooting a still image;
A shake detection sensor for detecting the shake of the lens barrel;
Control means for controlling the drive means based on the shake detected by the shake detection sensor and moving the movable part so that the image to be captured is stabilized;
Maximum value limiting means for limiting the maximum value of the shake detection value detected by the shake detection sensor and used for controlling the drive means based on the shooting mode determined by the shooting mode determination means;
An anti-vibration actuator comprising:   The maximum value limiting means limits the maximum value of the shake detection value to be lower than the maximum value in the still image shooting mode when the shooting mode determined by the shooting mode determination means is the moving image shooting mode. Anti-vibration actuator as described.   3. The vibration-proof actuator according to claim 1, wherein the shake detection sensor is a sensor that detects a shake angular velocity, and the maximum value limiting unit limits a maximum value of a shake angular velocity used for controlling the driving unit. A lens unit that is attached to a camera body and has an image blur correction function in movie shooting and still image shooting.
A lens barrel;
An imaging lens arranged in the lens barrel;
A fixed portion fixed to the lens barrel;
An image blur prevention lens that is moved to correct image blur;
A movable part to which the image blur prevention lens is attached;
Movable part support means for supporting the movable part movably with respect to the fixed part;
Driving means for applying a driving force between the fixed portion and the movable portion to drive the movable portion with respect to the fixed portion;
Shooting mode reading means for reading from the camera body whether the setting in the camera body is in a moving image shooting mode for shooting a moving image or a still image shooting mode for shooting a still image;
A shooting mode determination unit that determines whether the shooting mode read from the shooting mode reading unit is a moving image shooting mode or a still image shooting mode;
A shake detection sensor for detecting the shake of the lens barrel;
Control means for controlling the drive means based on the shake detected by the shake detection sensor and moving the movable part so that the image to be captured is stabilized;
Maximum value limiting means for limiting the maximum value of the shake detection value detected by the shake detection sensor and used for controlling the drive means based on the shooting mode determined by the shooting mode determination means;
A lens unit comprising: A camera having an image blur correction function in video shooting and still image shooting,
The camera body,
A lens barrel;
An imaging lens arranged in the lens barrel;
A fixed portion fixed to the lens barrel;
An image blur prevention lens that is moved to correct image blur;
A movable part to which the image blur prevention lens is attached;
Movable part support means for supporting the movable part movably with respect to the fixed part;
Driving means for applying a driving force between the fixed portion and the movable portion to drive the movable portion with respect to the fixed portion;
A shooting mode determining means for determining whether a moving image shooting mode for shooting a moving image or a still image shooting mode for shooting a still image;
A shake detection sensor for detecting the shake of the lens barrel;
Control means for controlling the drive means based on the shake detected by the shake detection sensor and moving the movable part so that the image to be captured is stabilized;
Maximum value limiting means for limiting the maximum value of the shake detection value detected by the shake detection sensor and used for controlling the drive means based on the shooting mode determined by the shooting mode determination means;
A camera characterized by comprising:

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