JP2009008929A - Shake correctable imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that shake images are imaged without proper camera shake correction when a camera is shaken by operation of a camera shake correction mechanism mounted on an imaging device to maintain mechanic vibration. <P>SOLUTION: The imaging device comprises a gyro sensor for detecting camera shake, a vibration prevention control circuit, and an ultrasonic actuator. The vibration prevention control circuit has a camera shake correction system provided with an optical parameter restriction part setting an upper limit to a shake correction amount calculated if a focal distance value by lens information is a predetermined focal distance value or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus capable of correcting blur by an actuator that moves an imaging unit in a predetermined direction by using elliptical vibration of a vibrator.

  In general, for example, a camera with a camera shake function is known as an image pickup apparatus equipped with a camera shake correction mechanism for preventing image quality deterioration due to camera shake or the like that occurs during imaging. As a camera shake correction mechanism provided in this camera, a shake signal is detected using shake detection means such as an angular velocity sensor for shake vibration in the camera pitch direction and shake vibration in the camera yaw direction. Based on the blur signal, a part of the imaging optical system or the imaging element is shifted independently in the horizontal direction and the vertical direction in a plane orthogonal to the imaging optical axis in a direction to cancel the blur. Due to these shifts, the imaging position of the subject image on the imaging surface of the imaging element does not move, and thus correction is made so that blurring that occurs in the captured image is reduced.

  In such a camera shake correction mechanism, some lenses or image sensors are shifted by an original drive mechanism, and a high responsiveness to perform a correction operation following the generated camera shake and a precision drive (micro drive). ) And self-holding ability that maintains the position of the moving body even when the power is turned off.

In order to satisfy these requirements, for example, Patent Document 1 proposes a camera shake correction mechanism using an impact actuator. Similarly, Patent Document 2 proposes a vibration wave linear motor that linearly drives a shaft with respect to the vibrator by pressing two vibrators that generate elliptical vibrations on the surface against the shaft. . In a drive mechanism equipped with this vibration wave linear motor, a cylindrical shaft is relatively moved by a vibrator, and a lens frame is driven by a protrusion provided on the shaft. The lens frame is configured to move while being guided in a moving direction by a guide mechanism provided for the lens frame.
JP 2005-331549 A Japanese Patent Laid-Open No. 2006-067712

  The camera shake correction mechanism using the actuator shown in Patent Document 2 described above as a drive source can realize high responsiveness, precision drive, and self-holding. However, in order to generate a large driving force in the vibration wave motor, it is necessary to press the vibrator against the moving member with a large force. In order to increase the rigidity of the moving member, a heavy metal member must be used, and this weight is generated as vibration when the drive mechanism is driven.

  Therefore, when the camera shake correction is performed, this vibration is transmitted to the camera and detected by the gyro sensor for detecting the camera shake. When the detected vibration signal is larger than a certain level with respect to the actual camera shake signal, camera shake correction is performed so as to follow the vibration signal rather than the camera shake signal. The camera is shaken by driving the correction mechanism (ultrasonic motor drive or the like), and mechanical vibration is further increased and maintained. As a result, even if the camera shake actually stops below a certain level, it is determined that camera shake is still occurring because it detects mechanical vibration during the shake correction operation. The camera shakes without stopping the camera shake correction operation (hereinafter referred to as an oscillation state). If imaging is performed in such an oscillation state, the original camera shake correction is not performed and a blurred image may be captured.

  Therefore, the present invention provides an image pickup apparatus capable of shake correction using a vibration wave motor as a drive source, which is not affected by an image pickup situation, performs proper shake correction, and performs normal image pickup without camera shake. The purpose is to provide.

  In order to achieve the above object, the present invention provides a photographic lens, information input means for inputting information of the photographic lens, a shake detection circuit, an image sensor for acquiring an image formed by the photographic lens as image data, A holding mechanism that holds the image pickup device on a surface perpendicular to the optical axis of the photographing lens by using the actuator as a drive source; an output of the shake detection circuit; and the information input means And a control circuit for controlling the actuator based on the displacement signal. The control circuit is configured to control the actuator when the focal length information is equal to or greater than a predetermined value. An image pickup apparatus capable of shake correction that obtains the displacement signal from the predetermined value and the shake signal is provided.

  The camera further includes an imaging lens, information input means for inputting information on the imaging lens, a shake detection circuit, an image sensor for acquiring an image formed by the imaging lens as image data, and an actuator. The actuator is driven. A holding mechanism for holding the image sensor as a source on a surface perpendicular to the optical axis of the photographing lens, and an output of the blur detection circuit and focal length information input by the information input means. A control circuit that obtains a displacement signal and controls the actuator based on the displacement signal, and the control circuit low-passes the output of the shake detection circuit when the focal length information is a predetermined value or more. Provided is an imaging device capable of performing blur correction and performing blur correction to obtain the displacement signal from the output of the processing and the focal length information.

  In addition, the imaging lens includes an imaging lens, information input means for inputting information of the imaging lens, a shake detection circuit, an image sensor that acquires an image formed by the imaging lens as image data, and an actuator. The actuator is driven. A holding mechanism for holding the image sensor as a source on a surface perpendicular to the optical axis of the photographing lens, and an output of the blur detection circuit and focal length information input by the information input means. A control circuit that obtains a displacement signal and controls the actuator based on the displacement signal, the control circuit having a cutoff frequency with respect to the displacement signal when the focal length information is a predetermined value or more. An image pickup apparatus capable of blur correction that performs a low-pass filter process (phase compensation filter) in which a phase is delayed in a predetermined band including the above.

  According to the present invention, an image pickup apparatus capable of shake correction using a vibration wave motor as a drive source, which is not affected by an image pickup situation, performs proper shake correction, and performs normal image pickup without camera shake. Can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
An image pickup apparatus capable of shake correction according to the present invention is an apparatus equipped with a shake correction system having an ultrasonic motor serving as an actuator for performing camera shake correction of an image pickup unit including an image pickup element that obtains an image signal by photoelectric conversion. Here, an example of application to a single-lens reflex electronic camera (digital camera) with interchangeable lenses will be described as an example of an imaging apparatus.

FIG. 1 shows a configuration example of a camera system equipped with a camera shake correction system according to this embodiment.
In this camera, the lens unit 10 is mounted on a body unit 100 serving as a camera body, and is electrically connected by a communication connector 7 so that they can communicate with each other. In this camera, a lens control microcomputer Lucom5 (lens system control unit) is configured to operate while being subordinately cooperating with a body control microcomputer Bucom50 (main body control unit).

  The lens unit 10 includes a photographing lens 1 and a diaphragm 3 on the optical axis. The taking lens 1 is driven by a DC motor (not shown) provided in the lens driving mechanism 2. The diaphragm 3 is driven to open and close by a stepping motor (not shown) provided in the diaphragm mechanism 4. Lucom 5 controls each of these motors based on a command from Bucom 50. The lens memory (EEPROM) 6 stores lens characteristic information (focal length, lens type, maximum FNo, minimum FNo, etc.).

The following structural members are disposed in the body unit 100.
A single-lens reflex component (for example, a pentaprism 12, a quick return mirror 11, an eyepiece lens 13, and a sub mirror 11a) as an optical system, a focal plane shutter 15 on the imaging optical axis, and a reflected light beam from the sub mirror 11a In response, an AF sensor unit 16 for detecting the defocus amount is provided.

  Also, an AF sensor driving circuit 17 for driving and controlling the AF sensor unit 16, a mirror driving circuit 18 for driving and controlling the quick return mirror 11, and a shutter charging mechanism 19 for charging a spring for driving the front curtain and the rear curtain of the shutter 15. A shutter control circuit 20 that controls the movement of the front curtain and the rear curtain, and a photometric circuit 21 that performs photometric processing based on a photometric sensor 21a that detects a light flux from the pen tab rhythm 12 are provided. On the imaging optical axis, an imaging unit 14 that generates an image signal from a subject image formed by the optical system described above is provided.

  Next, the imaging unit 14 including the CCD 31 image sensor (hereinafter referred to as CCD) will be described with reference to FIG.

  As shown in FIG. 2, the image pickup unit 14 is mainly disposed on the photoelectric conversion surface side of the CCD image sensor 31 that is an image pickup element, and an optical low-pass filter (LPF) that removes a high-frequency component from a passing subject light flux. 32 and a dustproof filter 33 arranged opposite to each other at a predetermined interval on the front side of the optical LPF 32 are sequentially arranged forward on the optical axis, and are integrally attached to the holder 38.

  The CCD 31 is an imaging device that generates an image signal by photoelectric conversion from a subject light beam focused by the imaging optical system of the lens unit 10 and imaged on a light receiving surface (photoelectric conversion surface). In addition, a CMOS image sensor can be used as the image sensor. A dust filter 33 disposed oppositely on the front side of the optical LPF 32 at a predetermined interval; and a piezoelectric element 34 disposed on the periphery of the dust filter 33 for applying a predetermined vibration to the dust filter 33; Is provided.

  A piezoelectric element 34 having two electrodes is attached to the periphery of the dustproof filter 33. The piezoelectric element 34 vibrates when a drive signal having a predetermined frequency is applied to two electrodes from a dustproof filter control circuit 48. This vibration is propagated to the dustproof filter 33, and dust attached to the filter surface is removed. The image pickup unit 14 is provided with a vibration-proof unit 22 for correcting camera shake, which will be described later.

  The body unit 100 of the camera of the present embodiment uses a CCD interface circuit 23 that propagates an image signal generated by the CCD 31 in units of frames, a liquid crystal monitor 24, and a DRAM 25 and a flash ROM 26 that temporarily store image data. And an image processing controller 28 for image processing. The recording medium 27 is an external recording medium such as various memory cards or an external HDD, and is detachably attached to a communication connector (not shown) of the camera body, and appropriately records information and image data. In addition, a nonvolatile memory 29 made of an EEPROM, in which predetermined control parameters necessary for camera control are stored, is provided so as to be accessible from the Bucom 50.

  The camera casing is provided with a camera operation SW 52, an operation display LCD 51, and an operation display LED 51a. The Bucom 50 performs a camera operation in accordance with a user operation and displays the operation state.

  The camera operation SW 52 is a switch group including operation buttons necessary for operating the camera, such as a release SW, a mode change SW, or a power SW. Further, a battery 54 as a power source and a power supply circuit 53 that converts and supplies the voltage of the battery 54 to a voltage required by each circuit unit are provided. The power supply circuit 53 also includes a voltage detection circuit for detecting a change in voltage when supplied from an external power supply via a power supply terminal (not shown).

Next, the operation of each component of such a camera will be described.
First, an image signal is generated by the CCD 31 by a release operation by the user. The image processing controller 28 takes in an image signal from the CCD 31 by controlling the CCD interface circuit 23 in accordance with an instruction from the Bucom 50. This image signal is converted into a video signal (image data) by the image processing controller 28 and displayed on the liquid crystal monitor 24. The user can confirm the captured image from the display image on the liquid crystal monitor 24.

  The SDRAM 25 is a memory for temporarily storing image data, and is used as a work area when image data is converted. The image data is displayed on the liquid crystal monitor 24 and converted into JPEG data, and then stored in the recording medium 27.

  The mirror drive mechanism 18 is a mechanism for driving the quick return mirror 11 to the up position and the down position. When the quick return mirror 11 is in the down position, the light beam from the photographing lens 1 is divided and guided to the AF sensor unit 16 side and the pentaprism 12 side. By this division, it is possible to visually recognize the subject image to be imaged on the finder and the display monitor.

  The output from the AF sensor in the AF sensor unit 16 is transmitted to the Bucom 50 via the AF sensor driving circuit 17 and a known distance measurement process is performed. On the other hand, a part of the light beam that has passed through the pentaprism 12 is guided to a photometric sensor 21a in the photometric circuit 21, and a known photometric process is performed based on the amount of light detected here.

Next, the imaging unit 14 including the CCD 31 will be described with reference to FIG.
As described above, the imaging unit 14 includes the CCD 31 that is an imaging device, the optical low-pass filter (LPF) 32, and the dust-proof filter 33, and is integrally attached to the holder 38.

  The chip body 31 a of the CCD 31 is directly mounted on the flexible substrate 31 b disposed on the fixed plate 35. The flexible board 31b is electrically connected to the main circuit board 36 side by fitting the connection portions 31c and 31d from both ends thereof to the connectors 36a and 36b provided on the main circuit board 36. A frame member 31 f is disposed on the flexible substrate 31 b so as to surround the outer periphery of the CCD 31, and a protective glass 31 e is fixed so as to cover the CCD 31.

  A filter receiving member 37 made of an elastic member or the like is disposed between the CCD 31 and the optical LPF 32. The filter receiving member 37 is disposed at a position that avoids the effective range of the photoelectric conversion surface at the peripheral edge of the front surface of the CCD 31 and abuts in the vicinity of the peripheral edge of the optical LPF 32 so that the CCD 31 and the optical LPF 32 are in contact with each other. It is comprised so that substantially airtightness may be maintained between.

  A holder 38 that covers the CCD 31 and the optical LPF 32 in an airtight manner is disposed. In the holder 38, a rectangular opening 38a is formed at a substantially central portion around the imaging optical axis. The opening 38a is formed with a flange portion 38b projecting toward the inner peripheral side on the dust filter 33 side. The flange portion 38b fixes the constituent members of the optical LPF 32, the filter receiving member 37, the protective glass 31e, and the frame member 31f so as to be sandwiched between the flexible substrate 31b. Due to the fixing by the flange portion 38b, the position of each component is restricted in the imaging optical axis direction, and acts as a retainer for the front side from the inside of the holder 38.

  Further, a dust-proof filter holder is provided at the peripheral portion on the front side of the holder 38 so that the dust-proof filter 33 is protruded more to the front side than the step portion 38b around the step portion 38b in order to hold the dust filter 33 on the front surface of the optical LPF 32 with a predetermined interval. The part 38c is formed over the entire circumference.

  The dustproof filter 33 is formed in a circular or polygonal plate shape as a whole. The outer peripheral edge of the dustproof filter 33 is supported by the dustproof filter receiving portion 38c with the piezoelectric element 34 sandwiched between them by a pressing member 40 fixed by a screw 39. The pressing member 40 is formed by an elastic body such as a leaf spring. Further, an annular seal 41 is interposed between the piezoelectric element 34 and the dustproof filter receiving portion 38c, and an airtight state is ensured. The imaging unit 14 is configured in an airtight structure including the holder 38 formed in a desired size for mounting the CCD 31 in this way.

Next, the camera shake correction function in the camera of this embodiment will be described.
Here, let the direction of the imaging optical axis be the Z-axis direction, the X-axis direction that is the first direction orthogonal in the XY plane orthogonal to the imaging optical axis, and the Y-axis direction that is the second direction.

  The camera shake correction of the present embodiment is a correction for moving the CCD 31 so as to compensate for the generated blur. The image stabilization unit 22 includes a vibration reduction drive device that uses a vibrator that generates elliptical vibration when a predetermined frequency voltage is applied as a drive source, and moves a holder 38 provided with the CCD 31.

First, the operation principle of the vibrator used in the drive device of this embodiment will be described.
FIG. 3 is a schematic diagram showing the operation principle of the vibrator. The vibrator 200 includes a piezoelectric body 201 formed in a rectangular shape with a predetermined size, a pair of drive electrodes 202 and 203 formed in a centrally symmetrical manner by polarization while being biased toward one side of the piezoelectric body 201, and a drive Drive elements 204 and 205 serving as a drive unit provided at the surface position of the piezoelectric body 201 corresponding to the electrodes 202 and 203 are provided.

  When a positive voltage is applied to the drive electrode 202, as shown in FIG. 3A, the drive electrode 202 portion of the polarization structure is deformed so as to extend. On the other hand, the piezoelectric body 201 portion on the back side does not deform so as to extend, so that it deforms so as to form an arc as a whole.

  On the other hand, when a negative voltage is applied to the drive electrode 202, the drive electrode 202 portion of the polarization structure is deformed so as to contract as shown in FIG. On the other hand, since the portion of the piezoelectric body 201 on the back side does not shrink, the whole is deformed into an arc shape opposite to that in FIG. The same applies to the drive electrode 203 side.

  Therefore, in order to generate elliptical vibrations on the surfaces of the driver elements 204 and 205, a frequency voltage based on a sine wave having a predetermined frequency is applied to one of the polarized drive electrodes 202 of the piezoelectric body 201 and to the other drive electrode 203. A frequency voltage by a sine wave having a phase shift at the same frequency as the frequency voltage applied to the drive electrode 202 is applied. The frequency of the applied frequency voltage is such that the center of the piezoelectric body 201 is a bending vibration node, the driver elements 204 and 205 are bending vibration nodes, and the longitudinal vibration node of the piezoelectric body 201 is the bending vibration node. Set to a predetermined numerical value that matches. With this setting, the vibrator 200 includes the bending vibration shown in FIGS. 3A to 3C including the restored state shown in FIG. The elliptical vibration is generated on the surfaces of the driver elements 204 and 205. Therefore, by placing the movable body to be driven on the driver elements 204 and 205 side of the vibrator 200 while being in pressure contact with each other, the movable body moves according to the direction of the elliptical vibration generated on the surfaces of the driver elements 204 and 205. It becomes.

  At this time, by changing the phase difference of the frequency voltage applied to the drive electrodes 202 and 203, it is possible to change the shape of elliptical vibration generated on the surfaces of the drive elements 204 and 205. The moving speed of the moving body can be changed by changing the shape of the elliptical vibration.

  Here, the characteristics of the vibrator will be described with reference to FIGS.

  FIG. 4 shows the relationship between frequency and speed when a frequency voltage having a predetermined frequency whose phase is shifted by 90 ° is applied to the drive electrodes 202 and 203. As the frequency approaches the resonance frequency of the vibrator from the smaller side, the driving speed increases rapidly, and as the frequency shifts from the resonance frequency to the higher side, the driving speed gradually decreases.

  FIG. 5 shows velocity characteristics when the frequency is fixed and the phase is varied from −90 ° to 90 °.

  This velocity characteristic is a velocity 0 when the phase is 0 °, and the velocity increases approximately linearly as it approaches 90 °. For example, if the phase difference of the frequency voltage is 0 °, the speed is 0. If the phase difference is increased by a positive value, the moving speed gradually increases, and the maximum speed is reached when the phase difference is 90 °. On the other hand, when the phase difference is increased beyond 90 °, the speed gradually decreases, and when the phase difference is 180 °, the speed becomes zero again.

  On the contrary, when the phase difference is set to a negative value, the rotational direction of the elliptical vibration generated in the driver elements 204 and 205 is reversed, and the moving body can be driven in the reverse direction. Also in this case, the maximum speed is obtained when the phase difference is −90 °.

  Next, with reference to FIG. 6 to FIG. 9, a description will be given of the vibration isolation unit of the present embodiment using such a vibrator as a drive source. Here, FIG. 6 is an exploded perspective view showing a configuration example of the image stabilization unit of the present embodiment, and FIG. 7 is a schematic side view of the image stabilization unit in which the shape of each part shown in FIG. 6 is simplified. 8 is a schematic side view showing the X-axis drive mechanism portion in FIG. 7 extracted and enlarged, and FIG. 9 is a cross-sectional view showing the guide bearing structure.

  The anti-vibration unit 22 includes an X frame (first moving body) 301 on which the holder 38 is mounted so as to be movable in the Y-axis direction, and a frame (fixed member) 302 on which the X frame 301 is mounted so as to be movable in the X-axis direction. And comprising. The vibration isolation unit 22 moves the holder 38 in the X-axis direction and the Y-axis direction as a final moving object.

  The X frame 301 is a frame portion 301b that surrounds the opening 301a around the imaging optical axis, and the holder 38 is movably mounted thereon. The frame 302 is a frame portion 302b that surrounds the opening 302a around the imaging optical axis. The X frame 301 is movably mounted and is fixed to a camera body (not shown). Furthermore, an X-axis drive mechanism 310x that moves the X frame 301 in the X-axis direction relative to the frame 302 and a Y-axis drive mechanism 310Y that moves the holder 38 in the Y-axis direction relative to the X frame 301 are provided. . The image stabilization unit 22 displaces the X frame 301 on which the holder 38 is mounted in the X-axis direction, and displaces the X frame 301 in the Y-axis direction so that the CCD 31 mounted on the holder 38 can move within the XY plane. The displacement is moved two-dimensionally so as to compensate for blurring.

Next, the configuration of the X-axis drive mechanism unit 310x will be described.
The X-axis drive mechanism unit 310x includes an X-axis vibrator (first vibrator) 320x and a moving body (first moving body) 311x that is fixed to the X frame 301 and is driven together with the X frame 301. A sliding body (second moving body portion) 330x to be configured, and a pressing mechanism (biasing means) 340x for biasing the X-axis vibrator 320x toward the sliding body 330x are provided.

  The X-axis vibrator 320x includes driver elements (drive units) 321x and 322x that generate elliptical vibration in accordance with the operation principle of the vibrator 200 described above on one surface of a rectangular piezoelectric body 323x.

  The X-axis vibrator 320x has a vibrator holder 324x at a central position on the side opposite to the driver elements 321x and 322x, and a protrusion 325x formed on the vibrator holder 324x is fitted in a holding portion including a groove 342x of the frame 302. Match. By this fitting, the X-axis vibrator 320x is positioned and held so that movement in the X-axis direction is restricted. With such a configuration, a driving force due to elliptical vibration generated in the driver elements 321x and 322x acts in the X-axis direction.

  In the sliding body 330x, a sliding plate (sliding portion) 332x is fixed on a bearing (guided portion) 331x. The bearing 331x is fixed by a screw 333x or the like at a position where the driver elements 321x and 322x of the X-axis vibrator 320x are pressed and come into contact with the sliding plate 332x. Here, fixing by screwing is used, but the fixing method is not limited to this, and other fixing methods such as adhesion may be used.

  As shown in FIG. 6, the sliding body 330 x is formed smaller than the X frame 300 (a size corresponding to the X-axis vibrator 320 x). Further, the X frame 301 is formed of a resin material having low rigidity, aluminum, or the like, whereas the sliding plate 332x is formed of a material such as ceramic having high wear resistance and high rigidity, and a bearing 331x. Is a hardened material such as ferritic stainless steel that has been hardened to increase its rigidity.

  Further, a bearing (guide portion) 304x is provided which is fixed with a screw 303x so as to face the bearing 331x of the sliding body 330x across the opening (attachment portion) of the frame 302. As shown in FIG. 9, a V-groove 305x along the X-axis direction is formed on the bearing 304x, and a V-groove plate 306x for preventing wear is fixed thereto. As shown in FIG. 9, the bearing 331x has a V-groove 334x facing the V-groove 305x (V-groove plate 306x) of the bearing 304x.

  Here, the two balls 336x (rolling elements) positioned by the retainer 335x are sandwiched between the V grooves 305x and 334x, whereby the bearings 304x and 331x are arranged in one row along the X-axis direction. The structure has a single ball 336x. As shown in FIG. 8 and the like, the two balls 336x are positioned in the vicinity of the positions immediately below the driver elements 321x and 322x, and the movement in the X-axis direction is restricted by the retainer 335x. The rolling element is not limited to a ball but may be a roller.

  The pressing mechanism 340x includes a pressing plate 341x and a pressing spring 347x.

One end of the pressing plate 341x is fixed to the frame 302 by a screw 344x via a spacer 343x, and holds the X-axis vibrator 320x. The pressing spring 347x is disposed via a spacer 346x around a screw 345 that fixes the other end of the pressing plate 341x to the frame 302, and the driver elements 321x and 322x of the X-axis vibrator 320x are pressed against the sliding plate 332x. The pressing plate 341x is urged to do so. The pressing force by the pressing mechanism 340x is set to a very large force of about 15N (Newton).

  The bearing 331x is rotatable around an axis that passes through the center of the ball 336x and is parallel to the V-groove 334x. The bearing 331x is integrated with the X frame 301, and is located between the frame 302 and the X frame 301 at a position away from the bearing 331x in a direction different from the X axis direction (most diagonal position farthest on the frame portion 302b). One ball 307x (rolling element) is disposed therebetween.

  The ball 307x is held in a sandwiched state by an urging force of a spring 308x locked between the frame 302 and the X frame 301 in the vicinity of the ball 307x. The balls 307x are positioned so as to maintain the distance in the imaging optical axis (Z-axis) direction of the X frame 301 with respect to the frame 302. Here, the urging force of the spring 308x only needs to maintain the pinched state of the ball 307x, and is set a few steps weaker than the urging force of the pressing spring 347x.

  With this setting, the moving body 311x composed of the X frame 301 and the sliding body 330x can move with respect to the frame 302 by three-point support with two balls 336x and one ball 307x.

  Further, since the ball 307x is disposed on the opposite side of the ball 336x with the imaging optical axis and the opening 301a interposed therebetween, the distance between the ball 307x and the ball 336x can be separated, so that a stable three-point support structure is provided. It can be. As described above, according to the present embodiment, the three balls (rolling elements) can guide the moving direction of the moving body 311x and can also regulate the inclination, thereby enabling stable driving. The basic structure of the Y-axis drive mechanism unit 310y is the same as that of the X-axis drive mechanism unit 310x, and the same or corresponding parts are denoted by the same reference numeral with the suffix y, and description thereof is omitted.

  The Y-axis drive mechanism unit 310y uses the X frame 301 as a fixed member and the holder 38 as a first moving body unit (or a third moving body unit) to be moved. The holder 38 includes a sliding body (second moving body portion or fourth moving body portion) 330y which is fixed integrally and constitutes a moving body (second moving body) 311y to be driven together with the holder 38.

  Further, the vibration isolator unit 22 of the present embodiment includes an X-axis gyro 45x that detects a blur around the X-axis of the body unit 100 (blur in the pitch direction) and a blur around the Y-axis of the body unit 100 (blur in the yaw direction). ) For detecting Y) is disposed on the frame 302. A position detection sensor 44 including a hall element 351 disposed on the frame 302 and a magnet 352 disposed on the holder 38 so as to face the hall element 351 is provided.

The image stabilization control circuit 43 outputs a control signal to the vibrator drive circuit 42 based on the signals from the X-axis gyro 45x, the Y-axis gyro 45y, and the position detection sensor 44. The vibrator driving circuit 42 drives the X-axis vibrator 320x and the Y-axis vibrator 320y by this control signal. The image stabilization control circuit 43 executes a control operation in accordance with an instruction from the Bucom 50.

Next, the operation of the X-axis drive mechanism 310x will be described.
As described above, the driver elements 321x and 322x of the X-axis vibrator 320x are pressed against the sliding plate 332x with a strong biasing force by the pressing mechanism 340. In this state, when a predetermined frequency voltage is applied to the X-axis vibrator 320x to generate elliptical vibrations in the driver elements 321x and 322x, the sliding body 330x is driven in the rotational direction of the elliptical vibrations.

  In such a configuration, since the pressing force applied to the X-axis vibrator 320x is strong, if the rigidity of the sliding plate 332x and the bearing 331x constituting the sliding body 330x is weak, as indicated by a virtual line in FIG. In addition, the sliding plate 332x and the bearing 331x are bent due to the applied pressing force, and the driving elements 321x, 322x and the sliding plate 332x come into contact with each other, and the operation becomes unstable or stops operating. In this respect, in this embodiment, since the sliding plate 332x and the bearing 331x have high rigidity, the pressing contact state between the driver elements 321x, 322x and the sliding plate 332x is stabilized, and the driving force associated with the elliptical vibration is applied to the sliding plate. It is reliably transmitted to 332x and can be driven in the rotational direction of elliptical vibration with high efficiency. At this time, the sliding body 330x side having the sliding plate 332x is not in surface contact with the frame 302 but in contact with the rolling method by the ball 336x at the bearings 331x and 304x portions, so that the pressing force is strong. Also, the sliding body 330x moves reliably with little friction with respect to the frame 302.

  As shown in FIG. 6, since the bearings 331x and 304x have a single-row ball bearing bearing structure along the X-axis direction, the sliding body 330x is driven in the X-axis when driven by the X-axis vibrator 320x. Move only in the direction. When the sliding body 330x moves in this way, the X frame 301 to which the sliding body 330x is fixed also moves in the X-axis direction integrally with the sliding body 330x. In other words, the moving direction of the X frame 330x is also guided by the engagement between the bearings 331x and 304x having a ball bearing bearing structure in one row along the X axis direction. The bearing 331x passes through the center of the ball 336x and can rotate around an axis parallel to the V-groove 334x.

  The bearing 331x is integrated with the X frame 301. One ball 307x is disposed between the frame 302 and the X frame 301 at a position away from the bearing 331x in a direction different from the X-axis direction. As shown in FIG. 7, the moving body 311x composed of the X frame 301 and the sliding body 330x is supported at three points at a position separated from the frame 302 by two balls 336x and one ball 307x. Yes. For this reason, it moves stably on the frame 302 in the X-axis direction without causing any distortion due to rotation around the axis parallel to the V-groove 334x.

  Therefore, the guide support mechanism for the strong pressing portion with respect to the X-axis vibrator 320x may be a single-row ball bearing bearing structure along the X-axis direction by the bearings 331x and 304x, and the size and structure can be simplified. Note that the Y-axis drive mechanism 310y operates in the same manner as the X-axis drive mechanism 310x, and a description thereof is omitted here.

Next, the camera shake correction operation will be described.
A camera shake correction function (not shown) is turned on by a camera operation SW 52 for performing a plurality of settings. When a main switch (not shown) such as a shutter button is turned on, the Bucom 50 controls the image stabilization control circuit 43. Then, a signal for the vibrator drive circuit 42 to execute the initial operation is transmitted. By this signal, a predetermined frequency voltage is applied from the vibrator driving circuit 42 to the X-axis vibrator 320x and the Y-axis vibrator 320y, and the X frame 301 and the holder 38 are moved so that the center of the CCD 31 and the imaging optical axis coincide. Are driven in the X-axis and Y-axis directions, respectively. Hereinafter, this operation is referred to as centering.

  Thereafter, the shake signal of the body unit 100 detected by the X-axis gyro 45x and the Y-axis gyro 45y is taken into the image stabilization control circuit 43. Here, in the X-axis gyro 45x and the Y-axis gyro 45y, the signal output from the angular velocity sensor that detects the blur around one of the axes is amplified by a processing circuit and A / D converted to be subjected to an image stabilization control circuit. 43 is input.

  The image stabilization control circuit 43 calculates a shake correction amount based on the output signals of the X-axis gyro 45x and the Y-axis gyro 45y, and outputs a signal corresponding to the calculated shake correction amount to the vibrator drive circuit 42. The holder 38 and the X frame 301 on which the CCD 31 is mounted are driven by a Y-axis vibrator 320y and an X-axis vibrator 320x that are operated by an electric signal generated by the vibrator drive circuit 42. The drive position of the CCD 31 (holder 38) is detected by the position detection sensor 44 and sent to the image stabilization control circuit 43 for feedback control. Details of the camera shake correction control will be described later.

  Next, with reference to the flowchart shown in FIG. 11, the correction operation at the time of still image capturing of the Bucom 50 will be described. The correction operation in this embodiment is started after the release SW is turned on (1R on).

  First, when release SW1R is turned on by the user, lens information necessary for blur correction driving is transmitted to Tucom, which will be described later (step S1). Simultaneously with the transmission, a shake correction operation is started (step S2). In Tucom, a correction amount is calculated based on output signals of the X-axis gyro 45x and the Y-axis gyro 45y, and shake correction driving is performed according to the calculated correction amount. At this time, it is determined whether or not the release SW1R is turned off, that is, whether or not the imaging preparation start instruction is canceled (step S3). If it is turned off in this determination and the instruction is canceled (Yes), Bucom 50 transmits a stop instruction to Tucom and stops the blur correction drive (step S9). Thereafter, Bucom 50 transmits a centering instruction to Tucom, and performs centering of CCD 31 (step S10). Then, an imaging preparation start instruction waiting state (1R waiting state) is entered.

  On the other hand, if it is determined in step S3 that the release SW 1R is kept on, that is, if the imaging preparation start instruction is not released (No), is the release SW 2R turned on to indicate that the imaging start is instructed? It is determined whether or not (step S4). If it is determined in this determination that the release SW 2R is not turned on, that is, the imaging start is not instructed (No), the process returns to step S3 and waits in the instruction waiting state. On the other hand, when the release SW 2R is turned on and an instruction to start imaging is given (Yes), the Bucom 50 transmits an instruction to stop driving the blur correction driving to the Tucom, and stops the blur correction driving (step S5). . Thereafter, the Bucom 50 transmits a centering instruction to the Tucom, and centers the CCD 31 (step S6).

  Next, once stopped, the blur correction drive is started (step S7). In Tucom, the correction amount is calculated again based on the output signals of the X-axis gyro 45x and the Y-axis gyro 45y, and blur correction driving is performed according to the correction amount. Then, exposure is performed by driving the shutter (step S8). When the exposure is completed, the Bucom 50 stops the blur correction drive to Tucom (step S9), and then performs centering of the CCD 31 (step S10), and enters an imaging preparation start instruction waiting state (1R waiting state).

Here, the details of the camera shake correction control will be described with reference to FIG.
Here, since the X-axis and the Y-axis perform blur correction control independently of each other, only the X-axis will be described.

  As shown in FIG. 12, the image stabilization control circuit 43 includes an amplifying circuit 61 for the gyro sensor 45 (X-axis gyro 45x, Y-axis gyro 45y), an amplifying circuit 65 for the position detection sensor 44, and a camera shake correction control microcomputer ( Hereinafter referred to as Tucom). Tucom performs a camera shake correction control calculation in accordance with an instruction from Bucom 50. In this configuration, Tucom includes a correction amount calculation unit 62, a subtraction unit 63, and a gain unit 64.

  The X-axis shake amount of the camera is detected by the X-axis gyro 45x, amplified by the amplification circuit 61 in the image stabilization control circuit 43, A / D converted, and input to Tucom. In Tucom, a blur correction amount is calculated based on the signal and lens information, and a signal corresponding to the blur correction amount is sent to the vibrator drive circuit 42. The CCD unit 31 is driven by the X-axis vibrator 506 that operates according to the output signal of the vibrator drive circuit 42. The energy required for the driving is supplied from the power supply circuit 53. The drive position of the CCD unit 31 is detected by the position detection sensor 44, amplified by the amplification circuit 65, A / D converted, and input to the Tucom.

A method for calculating a signal supplied to the vibrator driving circuit 42 will be described.
The characteristics of the vibrator have been described above with reference to FIGS. Therefore, in FIG. 4, if the phase is changed in FIG. 5 in a state where the vibrator is vibrated at a frequency at which a desired speed is output, the speed control of the moving body can be performed. That is, based on the blur correction amount calculation result, the blur correction drive is performed by changing the phase difference between the drive signals applied to the electrodes 202 and 203 of the vibrator in real time via the vibrator drive circuit 42. It becomes possible.

Next, a method for determining the phase difference of the drive signals applied to the electrodes 202 and 203 will be described.
In Tucom, the correction calculation unit 61 calculates a shake correction amount based on the output signal of the X-axis gyro 45x. The subtractor 63 calculates the difference between the blur correction amount and the position detection value detected by the position detection sensor 44 (hereinafter referred to as a deviation). In the gain unit 64, a value “deviation × gain” derived by multiplying this deviation by a predetermined coefficient (hereinafter referred to as gain) is used as a phase difference of the drive signal applied to the electrodes 202, 203 from Tucom. A signal is transmitted to the drive circuit 42.

  Therefore, as the deviation is larger, a larger phase difference signal is input to the vibrator driving circuit 42, and the moving body can be driven faster. This is so-called feedback control.

  As described above, when a relatively large and heavy imaging unit (CCD and a holding mechanism that holds the vibrator so as to be displaceable) 14 is driven, vibration during driving of the imaging unit 14 is transmitted to the camera body. A gyro sensor 45 for detecting camera shake detects the vibration. That is, as indicated by the dotted line shown in FIG. 13, a positive feedback loop in which the gyro sensor 45 detects mechanical vibration occurs in the shake correction system.

  For example, even when the gyro sensor 45 detects the same angular velocity, the amount of blur on the imaging surface increases as the focal length of the lens unit increases. That is, when a lens with a long focal length is mounted, the influence of mechanical vibration is increased, and the risk of causing the oscillation described above is increased. If the blur angle detected by the gyro sensor is θ and the focal length of the lens is f, the blur amount on the imaging surface can be approximated as f × tan θ. When such oscillation occurs, control becomes impossible, and a blur image is captured even if camera shake does not occur. Therefore, the occurrence of oscillation must be avoided.

<First Embodiment>
Next, a first embodiment will be described.

  The first embodiment solves the above-described problem that the vibration caused by the drive of the imaging unit 14 is influenced by the positive feedback loop. FIG. 14 is a block diagram illustrating a camera shake correction system according to the first embodiment. In addition, the same referential mark is attached | subjected to the structural part shown in FIG. 12 in the structural part of this embodiment, and the detailed description is abbreviate | omitted.

  The blur correction amount on the imaging surface calculated from the output of the gyro sensor 45 is f × tan θ as described above. At this time, even if the blur correction amount is the same, if the value of the focal length f is large, the blur correction amount of the imaging unit 14 becomes large, and oscillation is easily induced. Therefore, the optical parameter limiting unit 66 limits the blur correction amount by setting an upper limit for the optical parameter based on the lens information (focal length information).

  That is, the optical parameter limiting unit 66 compares the focal length f (focal length information) of the photographing lens included in the lens information with the maximum focal length fmax set in advance as a predetermined value, so that the value of the focal length f is greater. When the maximum focal length fmax is exceeded, the calculation formula for the blur correction amount is fmax × tan θ. If the obtained focal length f is equal to or less than the maximum focal length fmax, the blur correction amount is calculated using the focal length obtained without any limitation.

  Therefore, the focal length f exceeding the maximum focal length fmax is replaced with the maximum focal length fmax, and the coefficient is output to the correction calculation unit 62.

  Hereinafter, the camera shake correction control will be described in detail with reference to the flowchart shown in FIG. Note that the flowchart shown in FIG. 15 shows Tucom's internal processing in steps S11 to S14 and steps S15 to S17 shown in FIG.

  At the start of the blur correction drive, first, the Bucom 50 acquires the focal length f of the lens from the Lucom, and is further transmitted from the Bucom 50 to the Tucom (step S11). In Tucom, it is determined whether or not the focal length f is greater than fmax (step S12). If the focal length f is greater than fmax in this determination (Yes), the focal length f is set to fmax, and oscillation is prevented by limiting the value of the focal length f (step S13). On the other hand, if the focal length f is not greater than fmax (No), the focal length f is used.

  Next, using the value of the focal length f, a blur correction amount on the imaging surface is calculated (step S14), and feedback control is performed based on the calculated blur correction amount (step S15). Next, it is determined whether or not there is an instruction to stop blur correction driving from the Bucom 50 (step S16). Until there is an instruction (No), the blur correction amount calculation and feedback control processing are repeated. On the other hand, after receiving an instruction to stop the shake correction drive (Yes), the ultrasonic actuator (ultrasonic motor) serving as the drive source for shake correction is stopped (step S17), and the Bucom 50 instruction is waited.

  As described above, the above-described oscillation can be prevented by limiting the focal length and performing the feedback control. When the value of the focal length of the lens is larger than a predetermined fmax, the blur correction amount on the imaging surface is calculated as all fmax. Therefore, the calculated blur correction amount always has an error, and the blur correction performance It is assumed that deterioration will occur. However, the focal length at which oscillation occurs is when the value is very large. A telephoto lens having a large focal length is large and heavy, and is rarely imaged by a user, and is usually fixed on a tripod. For this reason, the problem to a user hardly arises.

<Second Embodiment>
Next, a second embodiment will be described.

  FIG. 16 is a diagram illustrating a block configuration of a camera shake correction system according to the second embodiment. In addition, the same referential mark is attached | subjected to the structural part shown in FIG. 12 in the structural part of this embodiment, and the detailed description is abbreviate | omitted.

  In this embodiment, in addition to the configuration shown in FIG. 12, an oscillation prevention LPF 68 and a bypass SW 67 are provided in Tucom. That is, it is a configuration for controlling the passing frequency (frequency band) in the shake correction amount signal output from the correction amount calculation unit 62.

  Usually, the frequency band of camera shake is about 0 to 20 Hz, and the frequency band of mechanical vibration is about 100 Hz to 200 Hz. Since the frequency band of mechanical vibration is higher than the frequency band of camera shake, when the focal length of the lens is larger than the predetermined value flpf, the oscillation prevention LPF (Low) is used for signal processing of the gyro sensor detection signal as shown in FIG. By adding a (Pass Filter) 68 and attenuating the mechanical vibration detection signal, oscillation of the camera shake correction system can be prevented. Examples of the characteristics of the outgoing call prevention LPF 68 are shown in the Bode diagrams of FIGS. The characteristic of the oscillation prevention LPF 68 is that a signal in the frequency band of camera shake is allowed to pass without fluctuation in gain, and the frequency band of mechanical vibration is attenuated.

  The camera shake correction control will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 19 shows Tucom's internal processing in the blur correction drive start-blur correction drive stop of steps S2 to S5 and steps S7 to S9 shown in FIG.

  At the start of blur correction driving, the Bucom 50 first acquires the focal length f of the lens from the Lucom 5, and further transmits from the Bucom 50 to the Tucom (step S21). In Tucom, it is determined whether or not the focal length f is larger than flpf (step S22). If it is larger (Yes), 1 is set to the flag of the LPF flag (step S23). On the other hand, if the focal length f is equal to or less than flpf (No), the LPFflag flag is reset to 0 (step S24).

  After calculating the blur correction amount on the imaging surface (step S25), it is determined whether or not the flag of the LPF flag is 1 (step S26). If the flag is 1 (Yes), the oscillation prevention LPF 68 is used. Then, the LPF process having the above-described characteristics is performed on the calculated blur correction amount. On the other hand, when the flag is 0 (No), the bypass SW 67 is turned on, and the blur correction amount is transmitted to the subtraction unit 63 without performing the LPF process. Thereafter, feedback control is performed based on the calculated blur correction amount (step S28).

  Thereafter, it is determined whether or not there is an instruction to stop blur correction driving from the Bucom 50 (step S29), and until there is a stop instruction (No), the blur correction amount calculation process and the feedback control process are repeated. In step S29, after receiving an instruction to stop the vibration reduction driving (Yes), the driving of the ultrasonic motor of the camera shake correction mechanism is stopped (step S30), and the instruction of Bucom 50 is awaited.

  In the present embodiment, an oscillation prevention LPF 68 is disposed on the output side of the Tucom correction amount calculation unit 62, and filter processing is performed on the shake correction amount signal output from the correction amount calculation unit 62. Although there is, it is not limited to this. For example, as shown in the modification of FIG. 17, even if the anti-oscillation LPF 68 and the bypass SW 67 are provided on the input side of the Tucom correction amount calculation unit 62 and the filter processing is performed before the correction amount calculation, An equivalent effect of attenuating the frequency band signal can be obtained.

  As described with reference to FIG. 19, when the focal length f is smaller than a predetermined value, the signal of the entire frequency band is allowed to pass without performing the above-described oscillation prevention LPF processing. As shown in FIG. 18 (b), even when the cutoff frequency is set so that there is no gain attenuation in the camera shake frequency band as shown in FIG. 18 (a) when the oscillation prevention LPF 68 is interposed. In addition, a phase delay occurs in the camera shake frequency band, and the camera shake correction performance is slightly deteriorated. This is to prevent this. When the focal length is smaller than the predetermined value, the LPF processing is not performed, but the cutoff frequency of the oscillation prevention LPF 68 is set to a high value such that the phase delay in the camera shake frequency band becomes substantially zero. In addition, a method for preventing deterioration of camera shake correction performance may be used. In this case, in FIG. 16 and FIG. 17, the bypass SW that bypasses the oscillation prevention LPF 68 according to the lens information is not necessary.

  As described above, also in this embodiment, the same effect as that of the first embodiment described above can be obtained. In particular, when the focal length of the photographic lens is equal to or greater than a predetermined focal length, a signal in the frequency band of camera shake is allowed to pass through the signal detected by the gyro sensor 45 without fluctuation in gain, Signals in the frequency band of mechanical vibration can be attenuated, and camera shake correction can be performed correctly, and an oscillation state in which the camera continues to vibrate due to the correction operation can be avoided.

<Third Embodiment>
Next, a third embodiment will be described.

  FIG. 22 is a diagram illustrating a block configuration of a camera shake correction system according to the third embodiment. In addition, the same referential mark is attached | subjected to the structural part shown in FIG. 12 in the structural part of this embodiment, and the detailed description is abbreviate | omitted.

  In FIG. 12, the correction amount calculation result is input, the drive position of the imaging unit 14 is output, and the output transfer characteristic with respect to the input is shown in the Bode diagram of FIG. Usually, the frequency band that can be followed by the ultrasonic motor is set higher than the frequency band of camera shake as shown in FIG. 20 so as to sufficiently follow the frequency band of camera shake. For this reason, when a signal in the mechanical vibration frequency band is generated, the risk of following the signal and falling into an oscillation state increases. In order to prevent this, the follow-up performance of the mechanical vibration frequency band may be deteriorated when the focal length f of the lens is equal to or greater than a predetermined value fgain.

  That is, the loop gain of feedback control in the configuration shown in FIG. 12 is reduced. The Bode diagram of FIG. 21 shows the output transfer characteristic with respect to the input when the correction amount calculation result at this time is input and the drive position of the imaging unit 14 is output.

  In FIG. 21, as the gain in the mechanical vibration frequency band is smaller than 0 dB, the follow-up performance to the mechanical vibration frequency band deteriorates, and the risk of occurrence of oscillation decreases. However, if the feedback loop gain is simply reduced, as shown in the transfer characteristics of FIG. 21, gain reduction and phase delay occur in the camera shake frequency band, and the camera shake correction performance deteriorates.

  Therefore, a configuration in which a phase compensation filter as shown in FIG. 22 is inserted is used. This configuration provides a phase compensation filter 74 in series with the feedback loop to improve phase lag. The characteristic of the phase compensation filter 74 in this embodiment is a characteristic that compensates so that the gain increases in the frequency band of camera shake as shown in FIG. Thereby, it is possible to increase the loop gain in the camera shake frequency band while keeping the loop gain in the mechanical vibration frequency band small.

The camera shake correction control will be described with reference to the flowchart shown in FIG.
The flowchart shown in FIG. 24 shows Tucom's internal processing in the above-described steps S2 to S5 and steps S7 to S9 shown in FIG. In the flowchart in FIG. 19 described above, the same step numbers are assigned to the equivalent steps, and the description is simplified.

  At the start of blur correction driving, first, the Bucom 50 acquires the focal length f of the lens from the Lucom, and further transmits from the Bucom 50 to the Tucom (step S21). Tucom determines whether or not the focal length f is greater than fgain (step S22). If it is larger (Yes), the flag of GAINflag is set to 1 (step S31). On the other hand, if the focal length f is not greater than fgain in this determination (No), the GAINflag flag is reset to 0 (step S32).

  After calculating the shake correction amount on the imaging surface (step S25), it is determined whether the GAIN flag flag is 1 (step S33). If the flag is 1 (Yes), the calculated shake correction amount is determined. Based on, feedback control is performed by changing the feedback loop gain to a small value and adding phase compensation filter processing (step S34). On the other hand, when the flag is 0 (No), normal feedback control is performed (step S35). The Bucom 50 determines whether or not there is an instruction to stop the vibration reduction driving (step S29). Until there is an instruction to stop blur correction driving in this determination (No), the blur correction amount calculation and feedback control processes are repeated. After receiving the shake correction drive stop instruction, the drive signal supply to the ultrasonic motor is stopped, and the Bucom 50 instruction is waited thereafter.

  As described above, according to the present embodiment, when the correction amount calculation result is input and the drive position of the imaging unit 14 is output, the transfer characteristic of the output when the focal distance f with respect to the input is larger than fgain is shown in FIG. The characteristics are as follows. The transfer characteristic shown in FIG. 25 is a characteristic for reducing the gain in the mechanical vibration frequency band, and compared with the transfer characteristic before countermeasures shown in FIG. 20, there is a risk of oscillation at the time of imaging with a long focal length lens. Can be reduced. Furthermore, the transfer characteristic shown in FIG. 25 hardly causes a decrease in gain or phase delay in the camera shake frequency band. Compared with the transfer characteristic before inserting the phase compensation filter in FIG. Performance degradation can be minimized.

A modification of the third embodiment will be described.
When the characteristics shown in FIG. 25 described above are realized, if the frequency band that can be followed is low, the response until the feedback control system reaches a steady state may be delayed at the beginning of driving. In order to compensate for this, in addition to the configuration shown in FIG. 22, as shown in FIG. 26, a correction speed calculation unit 76 for branching and inputting the output signal of the amplifier circuit 61 input to Tucom, and a correction speed calculation unit An adder 75 for adding a feedforward control signal, which will be described later, output from 76 and an output signal of the phase compensation filter 74 is provided.

  With this configuration, the blur correction speed is calculated from the angular speed signal of the gyro sensor and the lens information. Then, the control (generally referred to as feedforward control) that gives the vibrator a phase difference signal necessary for outputting the blur correction speed derived from the motor characteristics shown in FIG. 5 is used together with the feedback control. . As a result, it is possible to compensate for the response deterioration caused by lowering the frequency band in which the feedback control system can follow, and to improve the follow-up performance at the beginning of driving.

The phase compensation filter 74 may always be interposed regardless of the focal length f of the lens. In that case, the characteristic of the phase compensation filter 74 may be changed so that the gain in the camera shake frequency band is increased when the focal length f of the lens is equal to or greater than a predetermined value. In that case, the bypass SW 73 that bypasses the phase compensation filter 74 according to the lens information is not necessary in the configurations of FIGS.
The above-described favorable effects can be obtained no matter how the first to third embodiments and modifications described above are combined.

  According to these embodiments, even with the camera shake correction system that drives the relatively large and heavy imaging unit 14, it is possible to prevent the occurrence of oscillation due to vibration that occurs during camera shake correction. Accordingly, the present invention provides an imaging apparatus that prevents a blur image from being captured by the blur correction system and performs the blur correction appropriately under any imaging situation.

(Appendix)
Furthermore, the present invention includes the following gist.
(1) a photographic lens for forming a subject image;
A focal length detection unit for detecting focal length information of the photographing lens;
A shake detection unit that detects a blur amount of a subject image in the pitch direction and the yaw direction;
An imaging unit that receives a subject image formed by the photographing lens and generates image data by photoelectric conversion;
A holding mechanism that mounts the image pickup unit and holds the image pickup unit so as to be displaceable on a plane perpendicular to the optical axis of the photographing lens;
A position sensor unit for detecting the position of the imaging unit;
An actuator for moving the imaging unit on a plane perpendicular to the optical axis;
A control unit that obtains a displacement signal limited based on a preset value of the focal length information detected by the focal length detection unit and controls a camera shake correction amount to the actuator based on the displacement signal. An imaging device that is characterized.

(2) The control unit
When the focal length information detected by the focal length detection unit exceeds the preset value, an optical parameter limiting unit for instructing a limit with the preset value as an upper limit;
A correction calculation unit that outputs a blur correction amount based on a displacement signal in consideration of the limitation by the optical parameter limiting unit with respect to the blur amount detected by the blur detection unit;
A subtractor for performing feedback control for outputting a deviation consisting of a difference between the blur correction amount and the position detection value detected by the position sensor;
A gain unit that outputs a camera shake correction signal derived by multiplying the deviation by a predetermined coefficient as the camera shake correction amount for driving the actuator;
The imaging apparatus according to item (1), further comprising:

(3) The control unit
A low-pass filter that passes only the frequency band of camera shake with respect to the shake amount detected by the shake detection unit, and
A correction calculation unit that outputs a blur correction amount based on a displacement signal including the blur correction amount that has passed through the low-pass filter;
When the focal length information detected by the focal length detection unit exceeds the preset value, the low-pass filter processing is selected, and when the focal length information is equal to or less than the preset value, a switch unit that selects non-low-pass filter processing;
A subtractor for performing feedback control for outputting a deviation consisting of a difference between the blur correction amount and the position detection value detected by the position sensor;
A gain unit that outputs a camera shake correction signal derived by multiplying the deviation by a predetermined coefficient as the camera shake correction amount for driving the actuator;
The imaging apparatus according to item (1), further comprising:

(4) a photographic lens for forming a subject image;
A focal length detection unit for detecting focal length information of the photographing lens;
A shake detection unit that detects a blur amount of a subject image in the pitch direction and the yaw direction;
An imaging unit that receives a subject image formed by the photographing lens and generates image data by photoelectric conversion;
A holding mechanism that mounts the image pickup unit and holds the image pickup unit so as to be displaceable on a plane perpendicular to the optical axis of the photographing lens;
A position sensor unit for detecting the position of the imaging unit;
An actuator for moving the imaging unit on a plane perpendicular to the optical axis;
Based on a comparison between the focal length information and a preset value, the blur correction amount to the actuator is reduced by a low-pass filter process that passes only the frequency range of camera shake with respect to the blur correction amount obtained from the focal length information. An imaging device comprising: a control unit that controls the imaging device.

  (5) The control unit reduces the cutoff frequency of the low-pass filter process when the focal length information exceeds the preset value compared to when the focal length information is equal to or less than the preset value. The imaging apparatus according to item (4), characterized in that:

(6) The control unit
A low-pass filter that passes the gain unchanged and passes only the frequency band of camera shake with respect to the blur amount detected by the blur detection unit;
A correction calculation unit that outputs a blur correction amount based on a displacement signal composed of the blur amount that has passed through the low-pass filter;
When the focal length information detected by the focal length detection unit exceeds the preset value, the low-pass filter processing is selected, and when the focal length information is equal to or less than the preset value, a switch unit that selects non-low-pass filter processing;
A subtractor for performing feedback control for outputting a deviation consisting of a difference between the blur correction amount and the position detection value detected by the position sensor;
A gain unit that outputs a camera shake correction signal derived by multiplying the deviation by a predetermined coefficient as the camera shake correction amount for driving the actuator;
The imaging apparatus according to item (4), further comprising:

(7) a photographic lens for forming a subject image;
A focal length detection unit for detecting focal length information of the photographing lens;
A shake detection unit that detects a blur amount of a subject image in the pitch direction and the yaw direction;
An imaging unit that receives a subject image formed by the photographing lens and generates image data by photoelectric conversion;
A holding mechanism that mounts the image pickup unit and holds the image pickup unit so as to be displaceable on a plane perpendicular to the optical axis of the photographing lens;
A position sensor unit for detecting the position of the imaging unit;
An actuator for moving the imaging unit on a plane perpendicular to the optical axis;
A control unit that obtains a displacement signal limited based on a preset value of the focal length information detected by the focal length detection unit, and controls a camera shake correction amount to the actuator based on the displacement signal;
The control unit has a position control loop that feed packs the position information of the imaging unit detected by the position sensor unit, and when the focal length information is equal to or greater than a predetermined value, a loop gain of the position control loop An imaging apparatus characterized by reducing the size of the image pickup apparatus.

(8) The control unit
A correction calculation unit that outputs a blur correction amount based on a displacement signal composed of the blur amount detected by the blur detection unit;
A subtractor for performing feedback control for outputting a deviation consisting of a difference between the blur correction amount and the position detection value detected by the position sensor;
A gain unit that outputs a camera shake correction signal derived by multiplying the deviation by a predetermined coefficient as the camera shake correction amount for driving the actuator;
When the focal length information detected by the focal length detection unit exceeds the preset value, it is provided at the output end of the gain unit in the position control loop so that the gain increases in the frequency band of camera shake. A phase compensation filter that compensates for
A switch unit that selects phase compensation filter processing when the focal length information exceeds the preset value, and selects non-phase compensation filter processing when the focal length information is equal to or less than the preset value. The imaging device according to (7).

(9) The control unit
When the focal length information exceeds the preset value, a correction speed calculation unit that calculates a feedforward compensation signal from the blur amount detected by the blur detection unit;
The imaging apparatus according to (7) or (8), wherein the actuator is controlled by the position control loop to which feedforward compensation is added.

(10) a photographic lens for forming a subject image;
A focal length detection unit for detecting focal length information of the photographing lens;
A shake detection unit that detects a blur amount of a subject image in the pitch direction and the yaw direction;
An imaging unit that receives a subject image formed by the photographing lens and generates image data by photoelectric conversion;
A holding mechanism that mounts the image pickup unit and holds the image pickup unit so as to be displaceable on a plane perpendicular to the optical axis of the photographing lens;
A position sensor unit for detecting the position of the imaging unit;
An actuator for moving the imaging unit on a plane perpendicular to the optical axis;
A control unit that obtains a displacement signal limited based on a preset value of the focal length information detected by the focal length detection unit, and controls a camera shake correction amount to the actuator based on the displacement signal;
The control unit has a position control loop that feed-packs position information of the imaging unit detected by the position sensor unit, and is provided at an output end of the gain unit in the position control loop. A phase compensation filter that compensates so that the gain is increased in a band; and when the focal length information exceeds the preset value, the control unit simultaneously reduces the loop gain of the position control loop, An imaging apparatus characterized by changing characteristics of the phase compensation unit.

(11) The control unit
When the focal length information exceeds the preset value, a correction speed calculation unit that calculates a feedforward compensation signal from the blur amount detected by the blur detection unit;
The imaging apparatus according to (10), wherein the actuator is controlled by the position control loop to which feedforward compensation is added.

  (12) The imaging apparatus according to any one of (1) to (11), wherein the photographing lens is an interchangeable lens that is detachable from the imaging apparatus.

  These measures prevent blurry image capturing due to oscillation, particularly when a long focal length lens is mounted. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a figure which shows an example of the block configuration of the imaging device carrying the camera-shake correction system in this invention. It is sectional drawing which shows the structural example of the imaging unit provided in the imaging device. It is a schematic diagram for demonstrating the operating principle of the vibrator | oscillator in an ultrasonic motor. It is a figure which shows the relationship between the drive frequency and drive speed in an ultrasonic motor. It is a figure which shows the phase and speed characteristic of the drive voltage in an ultrasonic motor. It is a disassembled perspective view which shows one structural example of the image stabilization unit of the camera-shake correction system with which an imaging device is equipped. It is a side view which simplifies and shows the shape of each component part of a vibration proof unit. It is a schematic side view which expands and shows the X-axis drive mechanism part in an anti-vibration unit. It is sectional drawing which shows the guide bearing structure contained in an X-axis drive mechanism part. It is a figure for demonstrating the rigidity of the sliding body in an anti-vibration unit. It is a flowchart for demonstrating correction | amendment operation | movement at the time of the still image imaging of the control part of a camera main body. It is a figure which shows the 1st structural example of a camera-shake correction system. It is a figure for demonstrating the positive feedback loop which detects the vibration in the 1st structural example of a camera-shake correction system. It is a figure which shows the block configuration of the camera-shake correction system in 1st Embodiment. 6 is a flowchart for explaining a correction operation of the camera shake correction system in the first embodiment. It is a figure which shows the block configuration of the camera-shake correction system in 2nd Embodiment. It is a figure which shows the modification of the block configuration of the camera-shake correction system in 2nd Embodiment. FIG. F is a diagram illustrating a transfer characteristic including a relationship between a gain and a phase with respect to a frequency of a transmission preventing LPF in the camera shake correction system according to the second embodiment. It is a flowchart for demonstrating correction | amendment operation | movement of the camera-shake correction system in 2nd Embodiment. It is a figure which shows the transfer characteristic which consists of a gain and a phase relationship with respect to the frequency of the transmission prevention LPF before the countermeasure for demonstrating the camera-shake correction system of 3rd Embodiment. It is a figure which shows the transfer characteristic which consists of a gain and a phase relationship with respect to the frequency of the transmission prevention LPF in the camera-shake correction system of 3rd Embodiment. It is a figure which shows the block configuration of the camera-shake correction system in 3rd Embodiment. It is a figure which shows the characteristic of the phase compensation filter in 3rd Embodiment. 10 is a flowchart for explaining a correction operation of the camera shake correction system according to the third embodiment. In 3rd Embodiment, it is a figure which shows the transfer characteristic of the output with respect to an input when the correction amount calculation result is input and the drive position of an imaging unit is output. It is a figure which shows the modification of the block configuration of the camera-shake correction system in 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Shooting lens, 2 ... Lens drive mechanism, 3 ... Diaphragm, 4 ... Diaphragm mechanism, 5 ... Lens control microcomputer Lucom, 6 ... Lens memory (EEPROM), 7 ..., 8 ..., 9 ..., 10 ... Lens unit 11 ... Quick return mirror, 11a ... Sub mirror, 12 ... Pentaprism, 13 ... Eyepiece, 14 ... Imaging unit, 15 ... Shutter, 16 ... AF sensor unit, 17 ... AF sensor drive circuit, 18 ... Mirror drive circuit, 19 DESCRIPTION OF SYMBOLS ... Shutter charge mechanism, 20 ... Shutter control circuit, 21 ... Photometry circuit, 22 ... Optical low-pass filter (LPF), 23 ..., 24 ..., 25 ..., 26 ..., 27 ..., 28 ..., 29 ..., 30 ..., 31 ... CCD image sensor, 31a ... Chip body, 31b ... Flexible substrate, 31e ... Protective glass, 31f ... Frame member, 32 Optical LPF 33: Dust filter 34: Piezoelectric element 35 ... Fixed plate 36 ... Main circuit board 36a, 36b ... Connector 37 ... Filter receiving member 38 ... Holder 42 ... Vibrator drive circuit 43 ... Prevention Vibration control circuit, 44 ... Position detection sensor, 45 ... Gyro sensor, 45x ... X-axis gyro, 45y ... Y-axis gyro, 50 ... Body control microcomputer Bucom, 51 ... Operation display LED, 52 ... Camera operation SW, 53 DESCRIPTION OF SYMBOLS ... Power supply circuit 61 ... Amplification circuit 62 ... Correction amount calculation part 63 ... Subtraction part 64 ... Gain part 65 ... Amplification circuit 66 ... Parameter restriction part 67 ... Bypass SW 68 ... Transmission prevention LPF, 100 ... Body unit, 320... Vibrator.

Claims (5)

A taking lens,
Information input means for inputting information of the photographing lens;
A shake detection circuit;
An image sensor for acquiring an image formed by the photographing lens as image data;
A holding mechanism that has an actuator and holds the image pickup device on a surface perpendicular to the optical axis of the photographing lens in a displaceable manner using the actuator as a drive source;
A control circuit that obtains a displacement signal of the image sensor from the output of the blur detection circuit and the focal length information input by the information input means, and controls the actuator based on the displacement signal;
When the focal length information is greater than or equal to a predetermined value, the control circuit obtains the displacement signal from the predetermined value and the blur signal. A taking lens,
Information input means for inputting information of the photographing lens;
A shake detection circuit;
An image sensor for acquiring an image formed by the photographing lens as image data;
A holding mechanism that has an actuator and holds the image pickup device on a surface perpendicular to the optical axis of the photographing lens in a displaceable manner using the actuator as a drive source;
A control circuit for determining a displacement signal of the image sensor from the output of the blur detection circuit and the focal length information input by the information input means, and controlling the actuator based on the displacement signal;
Have
When the focal length information is equal to or greater than a predetermined value, the control circuit performs low-pass filter processing on the output of the blur detection circuit, and obtains the displacement signal from the output of the processing and the focal length information. An image pickup apparatus capable of blur correction. A taking lens,
Information input means for inputting information of the photographing lens;
A shake detection circuit;
An image sensor for acquiring an image formed by the photographing lens as image data;
A holding mechanism that has an actuator and holds the image pickup device on a surface perpendicular to the optical axis of the photographing lens in a displaceable manner using the actuator as a drive source;
A control circuit for determining a displacement signal of the image sensor from the output of the blur detection circuit and the focal length information input by the information input means, and controlling the actuator based on the displacement signal;
Have
The control circuit performs low-pass filter processing in which a phase is delayed in a predetermined band including a cutoff frequency with respect to the displacement signal when the focal length information is a predetermined value or more. apparatus.   4. The image pickup apparatus capable of blur correction according to claim 1, wherein the photographing lens is an interchangeable lens that can be attached to and detached from the image pickup apparatus.   The image pickup apparatus capable of blur correction according to claim 1, wherein the actuator is an ultrasonic actuator using a piezoelectric element as a drive source.

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