JP2010271513A - Optical vibration-proof device and optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical vibration-proof device which suppresses rotation of a movable holding member without providing a mechanism for guiding the movable holding member or an actuator for suppressing rotation. <P>SOLUTION: The optical vibration-proof device has: the movable holding member 24 that holds a vibration-proof element L3; and first and second actuators that include magnets 26p and 26y, coils 30p and 30y, and yokes 25p, 25y, 31p and 31y as components, and generate thrust for shifting the movable holding member in first and second directions by energizing the coils. Suction force generated between the coils and the magnets of the first and second actuators with shifting of the movable holding member by the thrust generated by the first actuator is set as first suction force and second suction force. At least one component of the first actuator has shape for generating the first suction force so as to suppress rotation in a plane perpendicular to the optical axis direction of the movable holding member by the second suction force. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical image stabilizer that is mounted on an optical apparatus such as an imaging device or an interchangeable lens and reduces image blur.

The above-mentioned optical image stabilizer is configured so that a movable member including an optical element such as a lens or an image sensor such as a CCD sensor is orthogonal to the optical axis direction (hereinafter, optical axis orthogonal) Image blurring is reduced. In such an optical vibration isolator, it is necessary to smoothly move the movable member in the direction perpendicular to the optical axis, while preventing the movable member from rotating about the optical axis.
FIG. 2A shows a configuration of a conventional optical image stabilizer. Reference numeral 100 denotes a correction lens. Reference numeral 101 denotes a movable holding member that holds the correction lens 100. 102y is a yaw actuator for shifting and driving the movable holding member 101 in the yaw direction (horizontal direction) which is one of the directions orthogonal to the optical axis, and 102p is a pitch direction (vertical direction) perpendicular to the yaw direction. ) Is a pitch actuator for shift driving.
FIG. 2B shows the configuration of each actuator. Each actuator has a front yoke 74 fixed to the movable holding member 101 and a magnet 75 attached to the movable holding member 101 by being attracted to the front yoke 74. Each actuator has a coil 76 attached to the base member of the optical vibration isolator and a rear yoke 77 fixed to the base member on the rear side of the coil 76 (the side opposite to the magnet 75). In a state where the coil 76 is not energized, the coil 76 is in a position facing the magnet 75.
When the coil 76 is energized, a Lorentz force is generated by repulsion of the magnetic lines of force from the coil 76 and the magnet 75, and the movable holding member 101 is shifted in the yaw direction or the pitch direction using the Lorentz force as a thrust.
FIG. 2C shows a thrust 106 generated in the pitch actuator 102p when the movable holding member 101 is shifted in the pitch direction, and an attractive force 107p generated between the coil 76 and the magnet 75 in both actuators 102y and 102p. , 107y. The attraction forces 107p and 107y are forces that attempt to return the magnet 75 shifted together with the movable holding member 101 to the original position facing the coil 76, and are also referred to as return forces hereinafter.
As shown in FIG. 2B, the coil 76, the magnet 75, and the yokes 74 and 77 are formed in a symmetrical shape with the axes X, Y, and Z passing through the centers thereof as symmetry axes. In this case, the gravity center position of the thrust force 106 generated in the pitch actuator 102p and the gravity center position of the return force 107p coincide with each other (coaxially located) in a plane orthogonal to the optical axis direction.
However, the position of the center of gravity of the return force 107y generated in the yaw actuator 102y is located away from the position of the center of gravity of the thrust 106 and the return force 107y in the pitch actuator 102p. For this reason, a rotational moment 108 is generated in the movable holding member 101, and this rotational moment 108 causes the movable holding member 101, that is, the correction lens 100 to rotate around the optical axis. The rotation of the movable holding member 101 (correction lens 100) reduces the control accuracy of the position of the movable holding member 101, and consequently the performance of the optical image stabilizer.
In order to suppress such rotation of the movable holding member, Patent Document 1 discloses an optical vibration isolator provided with a guide shaft for preventing rotation while allowing a parallel shift of the movable holding member. Yes. Patent Document 2 discloses an optical vibration isolator provided with an actuator for suppressing the rotation of the movable holding member in addition to the pitch and yaw actuator.
Japanese Patent No. 3229899 JP-A-6-242485

However, in the optical vibration isolator disclosed in Patent Document 1, there is a problem of backlash between the guide shaft and a portion (sleeve portion) that engages with the guide shaft of the movable holding member and friction generated between them. Become. For example, the backlash in the yaw direction between the guide shaft that guides the movable holding member in the pitch direction and the sleeve portion of the movable holding member reduces the positional accuracy of the movable holding member in the yaw direction. Further, in this optical vibration isolator, a rotational moment acting on the movable holding member still exists. For this reason, a twist occurs between the guide shaft and the sleeve portion, and the friction between the guide shaft and the sleeve portion increases due to the twist, and the drive characteristics of the optical image stabilizer are deteriorated.
On the other hand, in the optical image stabilizer disclosed in Patent Document 2, by providing an actuator for suppressing rotation, not only the size of the apparatus is increased and the number of parts is increased, but also the control is complicated.
The present invention provides an optical vibration isolator capable of suppressing the rotation of the movable holding member without providing a mechanism for guiding the movable holding member and an actuator for suppressing rotation, and an optical apparatus including the same.

An optical vibration isolator as one aspect of the present invention holds a base member and an anti-vibration element, and each of the first direction and the second direction perpendicular to the optical axis direction and perpendicular to each other with respect to the base member. A movable holding member capable of shifting in the direction, a magnet attached to one member of the base member and the movable holding member, a coil attached to the other member, and a yoke forming a magnetic path are used as the respective constituent elements. The first actuator and the second actuator each generate a thrust force that shifts the movable holding member in the first direction and the second direction by energizing the coil. As the movable holding member shifts in the first direction due to the thrust generated by the first actuator, the suction force generated between the coils and the magnets of the first and second actuators is changed to the first suction force. And the second suction force. At this time, at least one component of the magnet, the coil, and the yoke in the first actuator is controlled so as to suppress rotation in a plane orthogonal to the optical axis direction of the movable holding member due to the second attractive force. It has the shape which generate | occur | produces the attraction | suction force of this.
An optical vibration isolator as another aspect of the present invention holds a base member and an anti-vibration element, and the first direction is perpendicular to the optical axis direction and perpendicular to the base member. And a movable holding member shiftable in the second direction, a magnet attached to one of the base member and the movable holding member, a coil attached to the other member, and a yoke forming a magnetic path, respectively. The component includes a first actuator and a second actuator that respectively generate thrusts that shift the movable holding member in the first direction and the second direction by energizing the coil. As the movable holding member shifts in the first direction due to the thrust generated by the first actuator, the suction force generated between the coils and the magnets of the first and second actuators is changed to the first suction force. And the second suction force. At this time, at least one component of the magnet, the coil, and the yoke in the first actuator is in a plane perpendicular to the optical axis direction of the movable holding member by the second attractive force with respect to the other components. It arrange | positions in the position which generate | occur | produces the 1st attraction | suction force so that rotation may be suppressed, It is characterized by the above-mentioned.
Note that the optical apparatus having the optical image stabilizer also constitutes another aspect of the present invention.

  According to the present invention, the rotation of the movable holding member due to the suction force generated in the second actuator is suppressed using the suction force generated in the first actuator. For this reason, rotation of the movable holding member can be satisfactorily suppressed without providing a guide mechanism or an actuator for suppressing rotation.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

3 and 4 show a lens barrel including an optical image stabilizer (image blur correction device) that is Embodiment 1 of the present invention. This lens barrel is used by being provided integrally with a photographing apparatus (optical apparatus) such as a video camera or a digital still camera.
The lens barrel has, in order from the object side, a variable magnification optical system (photographing optical system) configured by four convex and concave lens units. L1 is a fixed first lens unit, and L2 is a second lens unit that moves in the optical axis direction and performs zooming. L3 is a third lens unit (optical element) serving as an image stabilization element that shifts in a direction orthogonal to the optical axis direction (pitch direction and yaw direction: hereinafter also referred to as optical axis orthogonal direction) to reduce image blur. L4 is a fourth lens unit that performs a focusing operation that moves in the optical axis direction to correct image plane variation accompanying zooming and perform focus adjustment. AXL shown in FIG. 4 indicates the optical axis of the photographing optical system.
Reference numeral 1 denotes a fixed barrel that holds the first lens unit L1, and 2 denotes a second moving frame that holds the second lens unit L2. Reference numeral 3 denotes a shift unit as an optical image stabilizer that shifts the third lens unit L3 in the direction orthogonal to the optical axis. Reference numeral 4 denotes a fourth group moving frame that holds the fourth lens unit L4. Reference numeral 5 denotes a rear barrel to which an image sensor 58 such as a CCD sensor or a CMOS sensor is attached.

Reference numerals 6, 7, 8 and 9 are guide bars extending in the optical axis direction, and both ends thereof are held by the fixed lens barrel 1 and the rear lens barrel 5. The guide bars 6 and 7 guide the second moving frame 2 in the optical axis direction, and the guide bars 8 and 9 guide the fourth moving frame 4 in the optical axis direction.
The shift unit 3 has a shift base 23 as a base member sandwiched between the fixed barrel 1 and the rear barrel 5 and is fixed together with the fixed barrel 1 and the rear barrel 5 using three screws.
Reference numeral 10 denotes an aperture unit that adjusts the amount of light passing through the photographing optical system, and moves the aperture blades in opposite directions to change the aperture diameter. Reference numeral 10a denotes an aperture actuator such as a stepping motor that moves the aperture blades.
Reference numeral 11 denotes a VCM (voice coil motor) that moves the fourth moving frame 4 in the optical axis direction. The VCM 11 includes a magnet 11a, a yoke 11b, and a coil 11c. A Lorentz force is generated by energizing the coil 11c, and the Lorentz force moves the coil 11c and the fourth moving frame 4 holding the coil 11c in the optical axis direction. The coil 11 c is fixed to the coil holding part 4 a of the fourth moving frame 4.
A zoom motor 12 moves the second moving frame 2 in the optical axis direction, and a stepping motor is used. The zoom motor 12 has a lead screw 12a that rotates with the rotor. A rack 2a attached to the second moving frame 2 meshes with the lead screw 12a, and the second moving frame 2 moves in the optical axis direction by the rotation of the rotor and the lead screw 12a.

The torsion coil spring 2b urges the second moving frame 2 toward the guide bars 6 and 7 and urges the rack 2a toward the second moving frame 2 and the lead screw 12a. Thereby, the play in the direction orthogonal to the optical axis with respect to the guide bars 6 and 7 of the second moving frame 2, the play in the optical axis direction with respect to the second moving frame 2 of the rack 2a, and the engagement play with the lead screw 12a of the rack 2a are generated. Removed.
The VCM 11 is fixed to the rear barrel 5 with one screw. The zoom motor 12 is fixed to the fixed barrel 1 with three screws.
Reference numeral 14 denotes a photo interrupter that detects the movement of the light shielding portion 2c formed in the second moving frame 2 in the optical axis direction, and detects that the second moving frame 2 is located at a predetermined reference position. Used as a zoom reset switch.
Reference numeral 16 denotes an optical sensor having a light emitting part and a light receiving part. The optical sensor 16 reads the light emitted from the light emitting unit and reflected by the reflection pattern on the scale 15 fixed to the scale holding unit 4b of the fourth moving frame 4 by the light receiving unit. From the optical sensor 16, a pulse signal corresponding to the reflection pattern is output as the fourth moving frame 4 moves. By counting this pulse signal, the position of the fourth moving frame 4 can be detected.
Next, the structure of the shift unit 3 is demonstrated using FIG.5 and FIG.6. FIG. 5 shows the shift unit 3 in an exploded manner. FIG. 6 is an enlarged view of a portion (cross section) of the yaw actuator in the shift unit 3.
Reference numeral 23 denotes a shift base as a base member, which is fixed to the fixed barrel 1 and the rear barrel 5 as described above. Reference numeral 24 denotes a third lens unit L3 which shifts in the optical axis orthogonal direction (the pitch direction as the first direction and the yaw direction as the second direction) with respect to the shift base 23, in other words, in the optical axis orthogonal plane. This is a possible shift frame (movable holding member).
Reference numeral 20 denotes a magnet base. The magnet base 20 holds a magnet 26p, which is one of the constituent elements of the actuator for driving in the pitch direction, and a magnet 26y, which is one of the constituent elements of the actuator for driving in the yaw direction. In the following description, an actuator for driving in the pitch direction is referred to as a pitch actuator. An actuator for driving in the yaw direction is called a yaw actuator.
The magnet base 20 is fixed to the shift frame 24 with screws. Accordingly, the magnets 26p and 26y are attached (fixed) in a state of being positioned with respect to the shift frame 24, and the magnets 26p and 26y can be used for detecting the position of the shift frame 24.

The shift frame 24 and the magnet base 20 are coupled by screws with the metal plate 21 sandwiched between them. As the material of the metal plate 21, stainless steel or the like is suitable.
Reference numeral 22 denotes three balls arranged between the shift base 23 and the magnet base 20 and arranged at three positions around the optical axis in a plane orthogonal to the optical axis direction (hereinafter referred to as an optical axis orthogonal plane). ing. Between the ball 22 and the magnet base 20, the metal plate 21 described above is disposed. The provision of the metal plate 21 prevents the ball base 22 from scratching (striking) the ball base 22 when the lens barrel is impacted, thereby preventing the drive characteristics of the shift unit 3 from deteriorating. it can. Further, the ball 22 is held so as to be able to roll by a ball holding portion 23 a formed on the shift base 23.
The material of the ball 22 is preferably stainless steel or the like so as not to be attracted by the magnets 26y and 26p disposed in the vicinity thereof.
Each ball 22 is a metal fixed to the shift base 23 (the end surface in the optical axis direction of the ball holding portion 23a) and the magnet base 20 by an attractive force acting between magnets 26p and 26y and rear yokes 31y and 31p described later. It always abuts against the plate 21. Thereby, the shift frame 24 can be shifted in the optical axis orthogonal plane without causing the tilt with respect to the optical axis AXL.
Next, the configuration of the pitch and yaw actuator will be described. A subscript p attached to each symbol indicates a component of the pitch actuator, and a subscript y indicates a component of the yaw actuator.
As shown in FIG. 6, the magnets 26p and 26y described above are magnetized to the S pole and the N pole in the optical axis orthogonal direction and the optical axis direction. 25p and 25y are front yokes for closing the magnetic flux on the front side of the magnets 26p and 26y in the optical axis direction (forming a magnetic path). The front yokes 25p and 25y are attracted and fixed to the magnets 26p and 26y.
30p and 30y are coils fixed to the shift base 23, and face the magnets 26p and 26y in a non-energized state. 31p and 31y are rear yokes for closing the magnetic flux on the rear side of the magnets 26p and 26y (forming a magnetic path). The rear yokes 31p and 31y are disposed on the opposite side of the magnets 26p and 26y across the coils 30p and 30y, and are held by the shift base 23. The magnet 26p, the yokes 25p, 31p and the coil 30p constitute a magnetic circuit of the pitch actuator, and the magnet 26y, the yokes 25y, 31y and the coil 30y constitute a magnetic circuit of the yaw actuator.

  When the coils 30p and 30y are energized, Lorentz force is generated by repulsion between the magnetic lines 26p and 26y and the lines of magnetic force generated from the coils 30p and 30y in a direction orthogonal to the magnetization boundary of the magnets 26p and 26y. The Lorentz force acts as a thrust on the shift frame 24 via the magnet base 20 and shifts the shift frame 24 in the pitch direction and the yaw direction. Thus, the type of actuator in which the magnets 26p and 26y and the shift frame 24 to which the magnets 26p and 26y are attached shifts is referred to as a moving magnet type actuator.

In this embodiment, a shift unit including a moving magnet type actuator will be described. However, a moving coil type actuator in which a coil and a shift frame to which the coil is attached shifts may be used.
The pitch actuator and the yaw actuator are arranged with a phase difference of 90 degrees so that the Lorentz force is generated in the pitch direction and the yaw direction. By combining the shift in the pitch direction and the shift in the yaw direction, the shift frame 24 can be freely shifted within a predetermined range in the plane orthogonal to the optical axis.
In the shift unit 3 of the present embodiment, the frictional force acting on the shift frame 24 when the shift frame 24 shifts in the plane orthogonal to the optical axis is generated between the ball 22 and the metal plate 21 and between the ball 22 and the shift base 23 ( It is only rolling friction generated between the ball holding portion 23a). For this reason, the shift frame 24 can be smoothly shifted with a small thrust, and minute movement amount control is also possible.
Next, the position detection of the shift frame 24 will be described. Reference numerals 29p and 29y denote Hall elements as position detectors for detecting a change in magnetic flux density, which can be soldered to a flexible xisable printed cable (hereinafter referred to as FPC) 28. The FPC 28 is fixed to the shift base 23. Further, by fixing the FPC pressing metal fitting 27 to the shift base 23 with a screw, the positional displacement of the Hall element 29 due to the floating of the FPC 32 is prevented.
When the shift frame 24 shifts in the pitch direction or the yaw direction and the magnets 26p and 26y move with respect to the Hall elements 29p and 29y, electrical signals corresponding to changes in magnetic flux density are output from the Hall elements 29p and 29y. Based on this electrical signal, the position of the shift frame 24 (third lens unit L3) in the pitch direction and the yaw direction can be detected.
FIG. 7 shows an electrical configuration of the image pickup apparatus of the present embodiment. The components shown in FIGS. 3 to 6 are denoted by the same reference numerals as those in FIG.
Reference numeral 56 denotes a control circuit as control means, which is constituted by a CPU or the like. The control circuit 56 controls the zoom motor 12, the diaphragm actuator 10a, and the VCM 11.
The control circuit 56 counts the number of pulses of the pulse signal input to the zoom motor 12 after detecting that the second moving frame 2 is positioned at the reference position by the photo interrupter 8 as a zoom reset switch. Thereby, the amount of movement of the second moving frame 2 from the reference position (that is, the position relative to the reference position) is detected.

The control circuit 56 detects the position (opening diameter) of the diaphragm blades using a signal from the diaphragm encoder 36 configured using a Hall element. Furthermore, the control circuit 56 detects the position of the fourth moving frame 4 by counting the pulse signals output from the optical sensor 16.
A camera signal processing circuit 50 performs signal processing such as amplification processing and gamma correction processing on the output of the image sensor 58. Among the video signals subjected to these processes, the luminance signal Y is supplied to an AE gate 52 and an AF (autofocus) gate 51. Each of the AE gate 52 and the AF gate 51 sets a signal extraction range used for exposure control and focusing among all the video screens.
Reference numeral 53 denotes an AF signal processing circuit that processes the luminance signal Y from the AF gate 51, and extracts a high frequency component from the luminance signal Y to generate a contrast evaluation value signal.
Reference numeral 54 denotes a zoom switch, and reference numeral 55 denotes a zoom tracking memory. The zoom tracking memory 55 stores information on the positional relationship between the second moving frame 2 and the fourth moving frame 4 for maintaining the in-focus state for each subject distance. When the zoom switch 54 is operated, the control circuit 56 controls the zoom motor 12 to move the second moving frame 2 and perform zooming. At this time, the control circuit 56 is based on the information stored in the zoom tracking memory 55 so that the positional relationship between the second moving frame 2 and the fourth moving frame 4 corresponding to the subject distance at that time is maintained. The fourth moving frame 4 is moved by controlling the VCM 11.
In the AF operation, the control circuit 56 moves the fourth moving frame 4 by controlling the VCM 11 so that the contrast evaluation value signal from the AF signal processing circuit 53 shows a peak value.

Further, in order to obtain proper exposure, the control circuit 56 uses the average value of the output of the luminance signal Y that has passed through the AE gate 52 as a reference value so that the output of the aperture encoder 36 becomes a value corresponding to this reference value. Then, the aperture actuator 10a is controlled to control the amount of light.
Reference numerals 57 and 58 denote shake sensors such as a vibration gyro for detecting the shake of the lens barrel (that is, the imaging device) in the pitch direction and the yaw direction, respectively. The control circuit 56 controls the energization to the coils 30p and 30y based on the outputs from the shake sensors 57 and 58 and the signals from the hall elements 29p and 29y that detect the position of the shift frame 24, so that the shift frame 24 To reduce image blur.
Next, the configuration of the pitch actuator and the yaw actuator will be described. Here, as the shift frame 24 is shifted in the pitch direction by the thrust generated by the pitch actuator, the pitch and the attractive force generated between the coils 30p and 30y of the yaw actuator and the magnets 26p and 26y are respectively represented by the pitch attractive force. And the yaw suction force. The attraction force is a force for returning the magnets 26p and 26y shifted together with the shift frame 24 to the original positions facing the coils 30p and 30y, and can also be referred to as a return force.
When the pitch actuator is the first actuator, the yaw actuator corresponds to the second actuator, the pitch suction force corresponds to the first suction force, and the yaw suction force corresponds to the second suction force. Conversely, when the yaw actuator is the first actuator, the pitch actuator corresponds to the second actuator, the yaw suction force corresponds to the first suction force, and the yaw suction force corresponds to the second suction force.

  In this embodiment, the pitch actuator generates the pitch suction force so as to suppress the rotation of the shift frame 24 in the plane orthogonal to the optical axis due to the yaw suction force generated by the yaw actuator. Specifically, at least one component of the pitch actuator magnet 26p, the coil 30p, and the yokes 25p and 31p has a shape that generates the pitch attractive force as described above. More specifically, the at least one component keeps the gravity center position of the pitch suction force away from the yaw actuator (on the far side) from the gravity center position of the thrust generated by the pitch actuator (hereinafter referred to as pitch thrust). Have a shape.

  The same applies to the yaw actuator. That is, the yaw actuator generates the yaw suction force so as to suppress the rotation of the shift frame 24 in the plane orthogonal to the optical axis due to the pitch suction force generated by the pitch actuator. Specifically, at least one component of the magnet 26y, the coil 30y, and the yokes 25y and 31y of the yaw actuator has a shape that generates the above yaw attractive force. More specifically, the at least one component moves the center of gravity of the yaw suction force away from the pitch actuator (shifts to the far side) from the center of gravity of the thrust generated by the yaw actuator (hereinafter referred to as yaw thrust). Has a shape.

FIG. 1 shows components of the pitch actuator and yaw actuator of this embodiment. Reference numeral 71 denotes a magnet, which corresponds to the magnets 26p and 26y described above. Reference numeral 72 denotes a coil, which corresponds to the coils 30p and 30y. Reference numerals 70 and 73 denote a front yoke and a rear yoke, which correspond to the front yokes 25p and 25y and the rear yokes 31p and 31y, respectively.
In FIG. 1, the Y-axis is an axis extending in the pitch direction or the yaw direction (thrust generation direction) through the center of the actuator (the center of the magnet 71 and the coil 30 in a non-energized state). The X axis is a direction passing through the center of the actuator, parallel to the optical axis orthogonal plane, and orthogonal to the Y axis. Furthermore, the Z axis is an axis that passes through the center of the actuator and extends in the optical axis direction.

As shown in FIG. 1, in this embodiment, the magnet 71, the coil 72, and the rear yoke 73 have a symmetrical shape with the Y axis as the axis of symmetry in the X axis direction, and the X axis is the axis of symmetry in the Y axis direction. It has a symmetrical shape. In the Z-axis direction, the magnet 71, the coil 72, and the rear yoke 73 all have a uniform thickness.
In contrast, the front yoke 70 has a symmetric shape with the X axis as the symmetric axis in the Y axis direction, but has an asymmetric shape with respect to the Y axis in the X axis direction. When the front yoke 70 constitutes a part of the pitch actuator, the front yoke 70 is formed such that the volume of the portion A farther from the yaw actuator than the Y-axis is larger than the portion B closer. Yes. Similarly, when the front yoke 70 constitutes a part of the yaw actuator, the front yoke 70 is configured such that the volume of the portion A on the side farther from the pitch actuator than the Y axis is larger than the portion B on the near side. The formed yoke can collect more magnetic flux and increase the magnetic flux density as its volume increases, and the higher the magnetic flux density, the greater the generated attractive force (return force). Therefore, the suction force generated on the portion A side of the front yoke 70 is larger than the return force generated on the portion B side, and the center of gravity position of the suction force generated on the entire front yoke 70 is Y axis (the center of the actuator). ) To the part A side.
On the other hand, as described above, since the coil 72 has a symmetrical shape in the Y-axis direction and the X-axis direction, the gravity center position of the thrust is the Y-axis position (the actuator center). Therefore, the gravity center position of the suction force generated by one of the pitch and yaw actuators is shifted farther from the other actuator with respect to the gravity center position of the thrust generated by the one actuator. Then, the suction force generated by shifting the center of gravity generated by one actuator acts to suppress the rotation of the shift frame 24 in the plane perpendicular to the optical axis due to the suction force generated by the other actuator.
Here, the center of gravity (position of the center of gravity) of thrust and suction force in the present embodiment will be described with reference to FIG. The dotted line in FIG. 9 shows the distribution of the thrust generated by the actuator in the X-axis direction, and the white arrow indicates that the total thrust, which is the total value (integrated value) of the thrust, acts on the position of the center of gravity. It shows a state. The thrust is distributed symmetrically with respect to the center of the actuator, with the peak at the center of the actuator. For this reason, the center of gravity of the thrust is located at the center of the actuator.
On the other hand, the solid line in FIG. 9 indicates the distribution of the suction force generated by the actuator, and the black arrow indicates that the total suction force, which is the total value (integral value) of the suction force, acts on the position of the center of gravity. Is shown. Actually, thrust and suction force are generated in opposite directions, but in FIG. 9, they are shown to act in the same direction.
As described above, by making the front yoke 70 asymmetric with respect to the center of the actuator, the peak of the suction force is deviated from the center of the actuator. For this reason, the center of gravity of the suction force is shifted from the center of the actuator to the side where the peak exists, that is, the portion A side of the front yoke 70.
FIGS. 8A and 8B show a simplified shift unit 3 of the present embodiment. FIG. 8A shows a state where the coils 30p and 30y of the pitch actuator and yaw actuator are not energized (non-energized state). 8B, the pitch actuator coil 30p is energized to generate a thrust in the pitch direction, and the shift frame 24, magnet 26p and front yoke 25p are shifted in the pitch direction from the state shown in FIG. 8A. It shows the state that was made to.
In FIG. 8B, 116 indicated by a solid line arrow indicates thrust (pitch thrust) generated by the pitch actuator, and the position of the solid line arrow in the X-axis direction corresponds to the barycentric position of the pitch thrust 116. Reference numerals 117p and 117y indicated by dotted arrows indicate suction forces (pitch suction force and yaw suction force) generated by the pitch actuator and yaw actuator, respectively, and act in the opposite direction to the pitch thrust 116. The position of the dotted arrow indicating the pitch suction force 117p in the X-axis direction corresponds to the position of the center of gravity of the pitch suction force 117p. The position in the Y-axis direction of the dotted arrow indicating the yaw suction force 117y corresponds to the position of the center of gravity of the yaw suction force 117y.
The yaw suction force 117y having the center of gravity away from the position of the center of gravity of the pitch thrust 116 attempts to rotate the shift frame 24 in the clockwise direction within the plane orthogonal to the optical axis, as described with reference to FIG. Generate a rotating moment.
However, as described above, the front yoke 25p of the pitch actuator is larger than the portion B on the side where the volume of the portion A far from the yaw actuator is close. For this reason, the gravity center position of the pitch suction force 117p is located farther from the yaw actuator (the gravity center position of the yaw suction force 117y) than the gravity center position of the pitch thrust 116. That is, the gravity center position of the pitch suction force 117p is located on the opposite side of the gravity center position of the pitch thrust force 116 from the gravity center position of the yaw suction force 117y. For this reason, the pitch suction force 117p generates a rotational moment that attempts to rotate the shift frame 24 counterclockwise within the plane orthogonal to the optical axis.
The counterclockwise rotation moment due to the pitch suction force 117p acts in a direction that counteracts the clockwise rotation moment due to the yaw suction force 117y, and thus the rotation of the shift frame 24 is suppressed. Thereby, the shift frame 24 can be shifted in parallel in the pitch direction in a state in which the rotation is suppressed in the plane orthogonal to the optical axis.
Note that when the thrust is generated in the yaw actuator and the shift frame 24, the magnet 26y, and the front yoke 25y are shifted in the yaw direction with respect to the shift base 23, the rotation of the shift frame 24 is similarly suppressed, and the shift frame 24 Can be shifted in parallel in the yaw direction.
Further, FIG. 10 shows a case where current is supplied to both the coils 30p and 30y of the pitch actuator and the yaw actuator. 116p is a pitch thrust generated by the pitch actuator, and 116y is a yaw thrust generated by the yaw actuator. 116py is a combined thrust of the pitch thrust 116p and the yaw thrust 116y.
117p is a pitch suction force generated in the direction opposite to the composite thrust 116py by the pitch actuator, and the center of gravity (starting point of the arrow) is located farther from the yaw actuator than the center of gravity of the pitch thrust 116p. 117y is a yaw suction force generated by the yaw actuator in a direction opposite to the combined thrust 116py, and its center of gravity is located farther from the pitch actuator than the center of gravity of the yaw thrust 116y.
The component force obtained by resolving the pitch suction force 117p in the pitch direction and the yaw direction is indicated by 117pa and 117pb. The component forces obtained by dividing the yaw suction force 117y in the pitch direction and the yaw direction are indicated by 117ya and 117yb.
For example, when the pitch thrust 116p is used as a reference, the pitch direction component 117pa of the pitch suction force 117p is counterclockwise with respect to the pitch direction component 117ya of the yaw suction force 117y that generates a clockwise rotational moment in the shift frame 24. Generates a rotational moment in the direction of rotation. For this reason, rotation of the shift frame 24 is suppressed. This is the same when the yaw thrust 116y is used as a reference.
FIG. 11 shows a case where current is supplied to both the pitch actuator and the yaw actuator coils in the conventional configuration.
117p ′ is a pitch suction force generated in the direction opposite to the composite thrust 116py by the pitch actuator, and the center of gravity (starting point of the arrow) is located closer to the yaw actuator than the center of gravity of the pitch thrust 116p. 117y ′ is a yaw suction force generated in the direction opposite to the combined thrust 116py by the yaw actuator, and its center of gravity is located closer to the pitch actuator than the center of gravity of the yaw thrust 116y.
For example, on the basis of the pitch thrust 116p, not only the pitch direction component force 117ya 'of the yaw suction force 117y' but also the pitch direction component force 117pa 'of the pitch suction force 117p' gives a clockwise rotational moment to the shift frame 24. generate. For this reason, the rotation of the shift frame 24 cannot be suppressed.
As described above, in this embodiment, the rotation of the shift frame 24 can be suppressed without providing a mechanism (for example, a guide shaft) or an actuator for suppressing the rotation of the shift frame 24. Thereby, the control accuracy of the position of the shift frame 24 is improved without increasing the play in the shift unit 3, increasing the number of components of the shift unit 3, or increasing the size of the shift unit 3. A shift unit 3 having performance can be realized.
In this embodiment, the shape of the component of the actuator that generates the thrust is asymmetric in the X-axis direction with respect to the center (Y axis) of the actuator, and the gravity center position of the suction force in the actuator is shifted from the gravity center position of the thrust Explained the case. However, the shape of the component for shifting the gravity center position of the suction force with respect to the gravity center position of the thrust is not limited to the asymmetric shape as described above. For example, even if the thickness in the Z-axis direction is varied in the X-axis direction, Good.
In the present embodiment, the case where the shape of the front yoke 70 is asymmetrical as shown in FIG. 1 has been described. However, as shown in FIG. 12 and FIG. 13, the gravity center position of the attractive force is made to be the thrust force by making the shape of the magnet 71 and the coil 72 asymmetrical, or making the shape of the rear yoke 73 asymmetrical although not shown. It is good also as a shape shifted with respect to a gravity center position.
Further, in the present embodiment, the case has been described in which one of the magnet, the coil, and the yoke (front yoke and rear yoke) is shaped to shift the gravity center position of the attractive force with respect to the gravity center position of the thrust force. However, two or more shapes of the magnet, the coil, and the yoke (front yoke and rear yoke) may be such shapes.

At least one component of the pitch, yaw actuator magnet, coil, and yoke (front yoke, rear yoke) is positioned to shift the gravity center position of the attraction force with respect to the gravity center position of the thrust with respect to the other components. By arranging, the same effects as in the first embodiment can be obtained.
That is, for example, when the shift frame 24 is shifted in the pitch direction by the pitch thrust generated by the pitch actuator, the suction force generated between the coil and the magnet of the pitch actuator and the yaw actuator is the pitch suction force and the yaw suction, respectively. Power. At this time, at least one of the magnets, coils, and yokes in the pitch actuator is pitched so as to suppress the rotation of the shift frame 24 in the plane perpendicular to the optical axis due to the yaw attractive force with respect to the other components. Arrange it at a position to generate suction force. Specifically, the at least one component is arranged with respect to the other components by shifting the center of gravity of the pitch suction force to a position farther from the yaw actuator than the center of gravity of the pitch thrust.
In addition, at least one component of the magnet, coil, and yoke in the yaw actuator is attracted by yaw so as to suppress the rotation of the shift frame 24 in the plane perpendicular to the optical axis due to the pitch attractive force with respect to the other components. Place in a position to generate force. Specifically, the at least one component is arranged with respect to the other components by shifting the position of the center of gravity of the yaw attractive force away from the position of the center of gravity of the yaw thrust.

14 to 17 show the positional relationship among the front yoke 70, the magnet 71, the coil 72, and the rear yoke 73 in each actuator when the pitch and yaw actuators are not energized.
In FIG. 14, the front yoke 70 is shifted from the magnet 71, the coil 72, and the rear yoke 73 in the direction of the arrow in the figure. In FIG. 15, the magnet 71 is arranged so as to be shifted in the direction of the arrow in the drawing with respect to the front yoke 70, the coil 72, and the rear yoke 73. In FIG. 16, the coil 72 is arranged by shifting the front yoke 70 with respect to the magnet 71 and the rear yoke 73 in the direction of the arrow in the figure. Further, in FIG. 17, the rear yoke 73 is arranged so as to be shifted in the arrow direction in the figure with respect to the front yoke 70, the magnet 71 and the coil 72.
In each of the above embodiments, the case where the shift moving frame 24 is shifted using a moving magnet type actuator has been described. However, the present invention can also be applied to the case of using a moving coil type actuator in which a coil is provided on the magnet base 20 (shift frame 24) side and a magnet is provided on the shift base 23 side.
In the above-described embodiments, the imaging apparatus in which the lens barrel is integrally provided in the camera body has been described. However, the present invention is also applicable to an interchangeable lens (optical apparatus) that can be attached to and detached from the imaging apparatus. Can do. Further, the present invention can also be applied to observation equipment (optical equipment) such as binoculars having a vibration isolation function.

Furthermore, in the above-described embodiments, the optical image stabilization device that shifts the optical element (lens unit) in the optical axis orthogonal direction has been described. It can also be applied to a vibration isolator.
Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

1 is an exploded perspective view illustrating a configuration of an actuator of a shift unit mounted on an imaging apparatus that is Embodiment 1 of the present invention. The figure which shows the force relationship (c) when shifting the structure (a) of the conventional shift unit, the structure (b) of the actuator, and a movable holding member. FIG. 3 is an exploded perspective view illustrating a configuration of a lens barrel of the imaging apparatus according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of a lens barrel in the first embodiment. FIG. 3 is an exploded perspective view of the shift unit according to the first embodiment. FIG. 3 is an enlarged cross-sectional view illustrating a part of the actuator of the shift unit according to the first embodiment. FIG. 2 is a block diagram illustrating an electrical configuration of the imaging apparatus according to the first embodiment. The figure which shows the force relationship (b) when shifting the structure (a) of a shift unit in Example 1, and a shift frame. The figure explaining the gravity center position of the thrust and suction force in Example 1. FIG. FIG. 6 is a diagram illustrating a force relationship when both the pitch actuator and the yaw actuator are energized in the shift unit according to the first embodiment. The figure which shows force relationship when electricity is supplied to both a pitch actuator and a yaw actuator in the conventional shift unit. FIG. 6 is a perspective view showing a modification of the first embodiment. FIG. 10 is a perspective view showing another modification of the first embodiment. The perspective view which shows the structural example of the actuator of the shift unit which is Example 2 of this invention. FIG. 12 is a perspective view illustrating another configuration example of the actuator of the shift unit according to the second embodiment. FIG. 12 is a perspective view showing another configuration example of the actuator of the shift unit according to the second embodiment. FIG. 12 is a perspective view illustrating still another configuration example of the actuator of the shift unit according to the second embodiment.

L1 First lens unit L2 Second lens unit L3 Third lens unit L4 Fourth lens unit 1 Fixed barrel 2 Second moving frame 3 Shift unit 4 Fourth moving frame 5 Rear barrel 10 Aperture unit 20 Magnet base 23 Shift base 24 Shift frame 25p, 25y, 70 Front yoke 26p, 26y, 71 Magnet 30p, 30y, 72 Coil 31p, 31y, 73 Rear yoke

Claims (5)

A base member;
A movable holding member that holds a vibration isolating element and is shiftable in a first direction and a second direction perpendicular to the optical axis direction and perpendicular to each other with respect to the base member;
A magnet attached to one member of the base member and the movable holding member, a coil attached to the other member, and a yoke forming a magnetic path are used as the respective constituent elements, and the movable member is energized by energizing the coil. A first actuator and a second actuator that respectively generate a thrust force for shifting the holding member in the first direction and the second direction;
The attraction force generated between the coil and the magnet of the first and second actuators as the movable holding member shifts in the first direction due to the thrust generated by the first actuator. Are the first suction force and the second suction force, respectively,
At least one component of the magnet, the coil, and the yoke in the first actuator suppresses rotation of the movable holding member in a plane perpendicular to the optical axis direction due to the second attractive force. Thus, the optical vibration isolator has a shape that generates the first suction force.   The at least one component has a shape in which the position of the center of gravity of the first suction force is further away from the second actuator than the position of the center of gravity of the thrust generated by the first actuator. Item 4. The optical image stabilizer according to Item 1. A base member;
A movable holding member that holds a vibration isolating element and is shiftable in a first direction and a second direction perpendicular to the optical axis direction and perpendicular to each other with respect to the base member;
A magnet attached to one member of the base member and the movable holding member, a coil attached to the other member, and a yoke forming a magnetic path are used as the respective constituent elements, and the movable member is energized by energizing the coil. A first actuator and a second actuator that respectively generate a thrust force for shifting the holding member in the first direction and the second direction;
The attraction force generated between the coil and the magnet of the first and second actuators as the movable holding member shifts in the first direction due to the thrust generated by the first actuator. Are the first suction force and the second suction force, respectively,
At least one component of the magnet, the coil, and the yoke in the first actuator is perpendicular to the optical axis direction of the movable holding member by the second attractive force with respect to the other components. An optical vibration isolator, which is disposed at a position where the first suction force is generated so as to suppress rotation in a plane.   The at least one component moves the center of gravity of the first suction force away from the second actuator relative to the other component than the center of gravity of the thrust generated by the first actuator. The optical image stabilizer according to claim 3, wherein the optical image stabilizer is disposed at a position.   An optical apparatus comprising the optical image stabilizer according to any one of claims 1 to 4.