JP2013003552A - Image blur correction device and optical instrument - Google Patents

Abstract

An image blur correction apparatus that is small in size, low in power consumption, and high in reliability is provided.
An image shake correction apparatus 100 includes a base member 101, an optical element 13 (or an image sensor), a movable member 102 movable in a first direction X, Y with respect to the base member, At least three support members 111a to 111c for positioning the movable member with respect to the base member in a second direction Z orthogonal to the direction 1, and a plurality of magnet members 117a provided on one of the base member and the movable member. ˜117c, and a magnetic member 107 provided on the other member of the base member and the movable member, and exerting a magnetic attractive force in the second direction between the magnetic member and the magnet member. When viewed from the second direction, the acting position of the resultant magnetic attraction force between the plurality of magnet members and the magnetic member is inside the polygon T connecting at least three support portions.
[Selection] Figure 5

Description

  The present invention relates to an image blur correction apparatus suitable for optical equipment such as a video camera, a digital still camera, an interchangeable lens, binoculars, a telescope, and a field scope.

  In order to prevent image deterioration due to camera shake such as camera shake, an optical system equipped with an image shake correction device (anti-vibration device) that moves (shifts) the image stabilization lens in a direction perpendicular to the optical axis according to camera shake. Equipment is known.

  In Patent Document 1, a shift member that holds a correction lens and shifts in a direction perpendicular to the optical axis is pressed against a base member by a biasing force of a spring, and the shift member is supported in the optical axis direction to support the light of the shift member. An image blur correction apparatus that performs positioning in the axial direction is disclosed. In this apparatus, a rollable ball is disposed between the shift member and the base member. The ball is sandwiched between the shift member and the base member by the biasing force of the spring, so that the shift member can be smoothly positioned (at a low driving load) by the actuator while positioning the shift member in the optical axis direction. A shift is possible.

  Further, in Patent Document 2, the shift member holds the yoke, while the base member holds the actuator driving magnet, and the shift member is made into the base member by the magnetic attraction between the driving magnet and the yoke. An image blur correction apparatus that is pressed is disclosed. Also in the image blur correction device disclosed in Patent Document 2, three balls are arranged between the shift member and the base member.

JP-A-10-319465 JP 2002-196382 A

  However, in the apparatus disclosed in Patent Document 1, when the shift member is shifted, a force (component force) is generated in the spring to return the shift member to the shift center. The driving load on the shift member increases. This leads to an increase in the size of the actuator and an increase in power consumption. Further, if the length of the spring is increased in order to reduce the component force, the apparatus may be increased in size.

  On the other hand, in the apparatus disclosed in Patent Document 2, the resultant force of the strong attractive force by the two drive magnets provided in the two actuators is biased with respect to the arrangement center of the three balls (three balls are Acts outside the connected triangle). For this reason, a large pressure is generated only between a specific ball of the three balls and its receiving surface, resulting in a decrease in durability and an increase in driving load. Further, when the shift member is inclined with respect to the base member due to an impact from the outside, the driving magnet and the yoke may be attracted, and driving may not be possible.

  The present invention provides an image blur correction apparatus that is small in size, low in power consumption, and high in reliability.

  An image shake correction apparatus according to one aspect of the present invention includes a base member, a movable member that holds an optical element or an imaging element and is movable in a first direction with respect to the base member, and is orthogonal to the first direction At least three support members for positioning the movable member with respect to the base member in the second direction, a plurality of magnet members provided on one of the base member and the movable member, and the other of the base member and the movable member. A magnetic member that is provided on the member and applies a magnetic attractive force in the second direction to the magnet member. And when viewed from the second direction, the acting position of the resultant magnetic attraction force between the plurality of magnet members and the magnetic member is inside the polygon connecting at least three support portions. And

  Note that the optical apparatus provided with the image blur correction device also constitutes another aspect of the present invention.

  According to the present invention, it is possible to realize an image blur correction apparatus that is small in size, low in power consumption, and high in reliability by appropriately setting the position of the resultant magnetic attraction force.

1 is a diagram illustrating a configuration of a lens apparatus that is Embodiment 1 of the present invention. FIG. FIG. 3 is an exploded perspective view of the image shake correction apparatus mounted on the lens apparatus according to the first embodiment when viewed from the front side. The exploded perspective view seen from the back side of the above-mentioned image blur correction device. The front view and sectional drawing of the said image blur correction apparatus. The side view and sectional drawing of the said image blur correction apparatus. The figure explaining the magnetic attraction force of the biasing magnet in the said image blur correction apparatus. FIG. 3 is a graph showing the relationship between the shift amount of the shift lens barrel and the magnetic attraction force in the image shake correction apparatus. Sectional drawing of the image blur correction apparatus of Example 2 of this invention. FIG. 6 is a diagram illustrating a magnetic attractive force of an urging magnet in the image shake correction apparatus according to the second embodiment. The graph which shows the relationship between a gap and magnetic attraction force.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a lens apparatus as an optical apparatus that is Embodiment 1 of the present invention, and the lens apparatus is equipped with an image blur correction apparatus (anti-vibration apparatus). The embodiments of the present invention include various optical devices such as a video camera, a digital still camera, an interchangeable lens, a binocular, a telescope, and a field scope (not shown).

  In FIG. 1, reference numeral 10 denotes a lens device. Reference numerals 11 and 12 denote shake detection sensors, which detect a shake of the lens apparatus 10 due to a shake or the like and output a signal (a shake signal) corresponding to the shake. The shake detection sensor 11 detects vertical shake (pitch shake), and the shake detection sensor 12 detects lateral shake (yaw shake). For example, angular velocity sensors are used as the shake detection sensors 11 and 12.

  Reference numeral 100 denotes an image blur correction apparatus. Reference numeral 13 denotes a correction lens (optical element) that moves (shifts) in a direction orthogonal to the optical axis, thereby displacing the optical axis in a direction orthogonal thereto. The correction lens 13 is held by a shift barrel described later.

  Reference numerals 14 and 15 denote position sensors, which detect the position of the correction lens 13 (shift barrel) and output a position detection signal. The position sensor 14 detects the position of the correction lens 13 in the yaw direction, and the position sensor 15 detects the position of the correction lens 13 in the pitch direction. Further, as the position sensors 14 and 15, it is desirable to use non-contact type sensors in order to reduce the driving load of the correction lens 13. In this embodiment, it is constituted by an infrared light emitting diode (IRED) fixed to the correction lens 13 (shift barrel) and a semiconductor position detecting element (PSD) for detecting infrared light emitted from the IRED. An optical sensor is used. In addition, as the position sensors 14 and 15, a magnetic sensor that detects a position based on a change in magnetic flux of a magnet, a sensor that detects a position based on a change in capacitance, a sensor that detects a position based on a change in electrical resistance, and the like are used. May be.

  A shake correction circuit 16 controls the position of the correction lens 13 based on shake signals from the shake detection sensors 11 and 12 and position detection signals from the position sensors 14 and 15. Specifically, the shake signal (angular velocity signal) from each shake detection sensor is integrated to obtain the shake displacement of the lens device 10, and the position of the correction lens 13 detected by the position detection signal from each position sensor is the shake. The position of the correction lens 13 is controlled so as to go to the target position corresponding to the displacement. As a result, image blur due to the shake of the lens device 10 is reduced (corrected).

  In this embodiment, the case where the position of the correction lens 13 is controlled in the closed loop using the position sensors 14 and 15 has been described. However, the position of the correction lens 13 may be controlled in the open loop without using the position sensor.

  In FIG. 2, the image blur correction apparatus 100 is disassembled as viewed from the front side (for example, the subject side). FIG. 3 shows the image shake correction apparatus 100 in an exploded manner as viewed from the rear side (for example, the image side). 4A and 4B, the image shake correction apparatus 100 is a surface along the optical axis shown in FIG. 4C (shown by the AA line and the BB line in the drawing). The cross section when cut is shown. Further, FIG. 5A shows a cross section when the image blur correction apparatus 100 is cut along a plane (indicated by a CC line in the drawing) orthogonal to the optical axis shown in FIG. .

  Each of the X direction and the Y direction in each figure is a direction (first direction) orthogonal to the optical axis, and is also a direction orthogonal to each other. The X direction corresponds to the direction of yaw shake detected by the shake detection sensor 12, and is hereinafter also referred to as the yaw direction. The Y direction corresponds to the direction of pitch shake detected by the shake detection sensor 11 and is hereinafter also referred to as pitch direction. In each figure, the shift barrel 102 holding the correction lens 13 is located at a reference position where the optical axis of the correction lens 13 coincides with the optical axis of the photographing optical system. The direction in which the optical axis of the correction lens 13 and the optical axis of the photographing optical system extend corresponds to the second direction, which will be referred to as the optical axis direction in the following description.

  A resin base plate 101 is fixed to the lens device 10 shown in FIG. The base plate 101 includes a cylindrical protrusion 101a protruding in the optical axis direction, and guide bar sliding portions 101b and 101c. A portion including the ground plane 101 and a member fixed thereto is also referred to as a fixed portion (or base portion) of the image blur correction apparatus 100. The ground plane 101 corresponds to “the other member of the base member and the movable member”.

  Reference numeral 102 denotes a shift lens barrel that holds the correction lens 13 and can be shifted (movable) in a plane perpendicular to the optical axis with respect to the base plate 101, that is, in the yaw direction and the pitch direction. The shift barrel 102 includes sub-plate fixing portions 102a, 102b, and 102c, a circular opening portion 102d, guide bar sliding portions 101e and 101f, a pitch slit 102g, and a yaw slit 102h. Note that the shift barrel 102, the correction lens 13, and a portion that is integrally shifted with respect to the base plate 101 are also referred to as a movable portion of the image blur correction apparatus 100. The shift barrel 102 corresponds to “one member of the base member and the movable member”.

  The shiftable range (movable range) of the shift barrel 102 will be described with reference to FIG. In FIG. 5C, the dotted line portion C in FIG. R1 indicates the radius of the outer periphery of the protrusion 101a, and R2 indicates the radius of the inner periphery of the opening 102d.

  The outer periphery of the protrusion 101a of the base plate 101 and the inner periphery of the opening 102d of the shift barrel 102 are configured to have a predetermined clearance in a direction perpendicular to the optical axis. That is, R2 is greater than R1. Further, the center of the outer periphery of the protrusion 101a and the center of the inner periphery of the opening 102d coincide. At this time, when the shift barrel 102 moves within the plane orthogonal to the optical axis by a distance (R2-R1) from the reference position, the outer periphery of the projection 101a and the inner periphery of the opening 102d come into contact with each other, and the shift barrel The shiftable range of 102 is limited. Since the outer periphery of the protrusion 101a and the inner periphery of the opening 102d are each circular, the shiftable range in a plane orthogonal to the optical axis of the shift barrel 102 is a circle with a radius (R2-R1).

  In this embodiment, the shiftable range of the shift barrel 102 is circular, but may be a range having other shapes such as a rectangle. Further, the center of the outer periphery of the protrusion 101a and the center of the inner periphery of the opening 102d do not have to coincide with each other. In this embodiment, the shiftable range of the shift barrel 102 is limited by the contact between the center of the outer periphery of the protrusion 101a and the inner periphery of the opening 102d. However, the shiftable range is limited for control purposes. It may be limited by other methods.

  Reference numeral 103 denotes a yaw drive coil, and reference numeral 104 denotes a pitch drive coil, which are respectively fixed to the shift barrel 102.

  Reference numerals 105a to 105d and 106a to 106d denote drive magnets formed of a magnet material such as a neodymium magnet. In the following description, the drive magnets 105 a to 105 d are also referred to as a first drive magnet group 105, and the drive magnets 106 a to 106 d are also referred to as a second drive magnet group 106.

  Reference numeral 107 denotes a first yoke as a magnetic member made of a magnetic material, and is fixed to the ground plate 101. A first drive magnet group 105 is fixed to the first yoke 107 by magnetic attraction. The first yoke 107 includes ball rolling portions 107a, 107b, and 107c formed as planes orthogonal to the optical axis, and magnet attracting portions 107d, 107e, and 107f formed as planes orthogonal to the optical axis. Have.

  Reference numeral 108 denotes a second yoke formed of a magnetic material. The second yoke 108 is disposed with a predetermined gap with respect to the shift barrel 102 in front of the shift barrel 102 and is fixed to the base plate 101 with screws. A second drive magnet group 106 is fixed to the second yoke 108 by magnetic attraction. For the first yoke 107 and the second yoke 108, for example, pure iron such as SUY or so-called soft magnetic material such as magnetic SUS can be used.

  The shift driving principle of the shift barrel 102 will be described with reference to FIG. The drive magnets 105c, 105d, 106c, and 106d are magnetized in the N-pole and S-pole in the optical axis direction, and form a magnetic path that passes through the first yoke 107 and the second yoke 108. One surface of the pitch drive coil 104 is arranged to face the drive magnets 105c and 105d with a predetermined gap in the optical axis direction. The other surface of the pitch drive coil 104 is disposed so as to face the drive magnets 106c and 106d with a predetermined gap in the optical axis direction.

  When the pitch drive coil 104 is energized, the Lorentz force in the Y direction acts on the pitch drive coil 104 by the magnetic field generated by the drive magnets 105c, 105d, 106c, and 106d. Then, the Lorentz force becomes a thrust, and the shift barrel 102 together with the pitch drive coil 104 is driven to shift in the Y direction. The shift drive direction of the shift barrel 102 can be reversed by switching the energization direction to the pitch drive coil 104. The shake correction circuit 15 shown in FIG. 1 controls the energization to the pitch drive coil 104 to shift the correction lens 13 fixed integrally with the shift barrel 102 in the Y direction. The same applies to driving in the X direction. When the yaw driving coil 103 is energized, the Lorentz force in the X direction acts on the yaw driving coil 103 by the magnetic field generated by the driving magnets 105a, 105b, 106a, and 106b. Then, the Lorentz force becomes a thrust, and the shift barrel 102 is driven to shift in the X direction together with the yaw drive coil 103.

  The pitch drive coil 104, the drive magnets 105c, 105d, 106c, and 106d, the first yoke 107, and the second yoke 108 constitute a pitch electromagnetic actuator. The yaw drive coil 103, the drive magnets 105a, 105b, 106a, 106b, the first yoke 107, and the second yoke 108 constitute a yaw electromagnetic actuator. The first yoke 107 is a yoke that forms a part of the magnetic path in these electromagnetic actuators, and generates a magnetic attraction force with an urging magnet, which will be described later, so that the shift barrel 102 faces the base plate 101. It also has the function of energizing.

  In the present embodiment, the drive coils 103 and 104 are fixed to the shift barrel 102 (that is, the movable side), and the drive magnets 105a to 105d and 106a to 106d are fixed to the base plate 101 (that is, the fixed side). Type actuator. However, a so-called moving magnet type actuator in which the drive coil is fixed to the fixed side and the drive magnet is fixed to the movable side may be employed.

  Reference numerals 109a, 109b, and 109c are disk-shaped sub-plates that are inserted into and fixed to the sub-plate fixing portions 102a, 102b, and 102c formed in the shift barrel 102 so that the surfaces thereof are surfaces orthogonal to the optical axis. Is done.

  111a, 111b, and 111c are three balls as support members formed of a nonmagnetic material. It should be noted that at least three balls (that is, supporting members) may be provided, and four or more balls may be provided. The three balls 111a, 111b, and 111c are arranged between the shift barrel 102 and the base plate 101 so as to be able to roll in the pitch direction and the yaw direction at three locations around the optical axis. These balls 111a, 111b, and 111c support the shift barrel 102 with respect to the base plate 101 in the optical axis direction. In other words, the balls 111 a, 111 b, and 111 c position the shift barrel 102 in the optical axis direction with respect to the base plate 101 while guiding the shift barrel 102 in the pitch direction and the yaw direction with respect to the base plate 101.

  As shown in FIG. 4B, the ball 111a is disposed between the ball rolling portion 107a of the first yoke 107 and the sub plate 109a. Similarly, the ball 111b is disposed between the ball rolling portion 107b and the sub plate 109b, and the ball 111c is disposed between the ball rolling portion 107c and the sub plate 109c. Each ball comes into contact with each ball rolling portion and each sub plate at one point, and rolls without sliding with respect to each ball rolling portion and each sub plate as the shift barrel 102 is shifted. Thereby, the shift barrel 102 can be shifted in the yaw direction and the pitch direction with a low load.

  The inner peripheral surfaces of the sub-plate fixing portions 102a, 102b, and 102c in the shift lens barrel 102 limit the rolling range in the plane orthogonal to the optical axis of the balls 111a, 111b, and 111c. Assume that the balls 111a, 111b, and 111c are positioned at the centers of the sub-plate fixing portions 102a, 102b, and 102c when the shift barrel 102 is positioned at the reference position. At this time, the sub-plate fixing portions 102a, 102b prevent the balls 111a, 111b, 111c from coming into contact with the inner peripheral surfaces of the sub-plate fixing portions 102a, 102b, 102c no matter where the shift barrel 102 is shifted. , 102c is set. Further, it is assumed that the balls 111a, 111b, and 111c are in contact with the inner periphery at the ends of the sub-plate fixing portions 102a, 102b, and 102c when the shift barrel 102 is located at the reference position. At this time, the diameters of the ball rolling portions 107a, 107b, and 107c in the first yoke 107 are set so that the balls 111a, 111b, and 111c do not fall off no matter where the shift barrel 102 is shifted. The

  Reference numeral 112 denotes a guide bar having an extending part 112a in the X direction and an extending part 112b in the Y direction. The extending portion 112 a in the X direction is engaged with guide bar sliding portions 101 b and 101 c provided on the main plate 101. Thereby, the guide bar 112 is held to be movable in the Y direction while being prevented from moving in the X direction and rotating around the optical axis with respect to the base plate 101. Further, the extending portion 112 b in the Y direction is engaged with guide bar sliding portions 102 e and 102 f provided in the shift barrel 102. As a result, the shift barrel 102 is held movably in the X direction while being prevented from moving in the Y direction and rotating around the optical axis with respect to the guide bar 112. Therefore, the shift barrel 102 moves only in the X direction and the Y direction in the plane orthogonal to the optical axis with respect to the base plate 101 via the guide bar 112, and is prevented from rotating.

  117a, 117b, and 117c are energizing magnets as magnet members that are formed in a cylindrical shape from a magnet material such as a neodymium magnet and are magnetized so that there are N and S poles in the optical axis direction. In the present embodiment, three (plural) biasing magnets 117 a, 117 b, and 117 c are fixed to the shift barrel 102.

  Reference numerals 118a, 118b, and 118c are back yokes made of a magnetic material, and form part of a magnetic path from the biasing magnets 117a, 117b, and 117c.

  As shown in FIG. 4B, the biasing magnet 117a is opposed to the magnet attracting portion 107d of the first yoke 107 with a predetermined gap in the optical axis direction. Magnetic attraction in the direction is generated. Similarly, a magnetic attractive force in the optical axis direction is also generated between the biasing magnet 117b and the magnet attracting portion 107e and between the biasing magnet 117c and the magnet attracting portion 107f. The shift barrel 102 is urged toward the base plate side in the optical axis direction by the resultant magnetic attraction force, and the balls 111a, 111b, and 111c disposed between the shift barrel 102 and the base plate 101 cause the shift barrel 102 to move. Positioning in the optical axis direction with respect to the base plate 101 is performed.

  In the present embodiment, the biasing magnets 117a, 117b, and 117c are fixed to the shift barrel 102 (one member) that is a part of the movable portion, and the first yoke 107 (magnet attracting portions 107d, 107e, and 107f) is attached. It fixed to the ground plane 101 (other member) which is a part of fixing part. However, the biasing magnet may be fixed to the base plate (one member), and the first yoke (magnet attracting portion) may be fixed to the shift barrel (the other member).

  In this embodiment, the biasing magnets 117a, 117b, and 117c have the same shape, and the gaps between the magnet attracting portions 107d, 107e, and 107f are set to be the same distance. For this reason, the magnetic attractive forces generated between the biasing magnets 117a, 117b, and 117c and the magnet attracting portions 107d, 107e, and 107f are the same as each other. However, the shapes of the biasing magnets 117a, 117b, and 117c and the gap distances between the magnet attracting portions 107d, 107e, and 107f may be different from each other.

  The shape of the first yoke 107 will be described with reference to FIGS. 6 and 7. In the following description, the energizing magnet 117a and the magnet attracting portion 107d will be described, but the same applies to the energizing magnet 117b and the magnet attracting portion 107e, and the energizing magnet 117c and the magnet attracting portion 107f.

  R3 is the radius of the biasing magnet 117a, and R4 is the radius of the magnet attracting portion 107d. Yg represents a gap (clearance) in the optical axis direction between the biasing magnet 117a and the magnet attracting portion 107d. X0, X1, X2, and X3 are shift amounts (movement amounts) of the shift barrel 102, and have a relationship of X0 <X1 <X2 <X3. F0 to F3 indicate magnetic attractive forces acting on the biasing magnet 117a. The optical axis direction is the Z direction, and the direction orthogonal to the optical axis is the X direction.

  FIG. 6A shows a state in which the shift barrel 102 is at the reference position. X0 = 0. The entire S pole surface of the biasing magnet 117a faces the magnet attracting portion 107d, and only the magnetic attractive force F0 in the Z direction acts on the biasing magnet 117a.

FIG. 6B shows a state in which the shift barrel 102 is shifted by X1 from the reference position. The entire S pole surface of the biasing magnet 117a faces the magnet attracting portion 107d, and only the magnetic attraction force F1 in the Z direction acts on the biasing magnet 117a. Since the clearance Yg in the optical axis direction does not change with respect to the state shown in FIG. 6A and no magnetic attractive force in the X direction is generated, the magnetic attractive force F1 satisfies the following relationship.
F1 = F0
In particular, the state shown in FIG. 6B shows a state where the shift amount of the shift barrel 102 is the largest among the states satisfying the above relationship. When the distance in the X direction from the end of the biasing magnet 117a to the end of the magnet attracting portion 107d in this state is α, the shift amount X1 satisfies the following expression.
X1 = R4-R3-α
When the shift amount X satisfies the following relationship, the magnetic attraction force in the X direction that becomes the driving load of the shift barrel 102 is not generated, and the power consumption of the image blur correction apparatus 100 can be reduced.
0 <X <X1
FIG. 6C shows a state in which the shift barrel 102 is shifted by X2 from the reference position. X2 is the maximum shift amount (maximum movement amount) of the shift barrel 102. As can be seen from FIGS. 6A to 6C, in the entire shiftable range of the shift barrel 102, at least a part of the urging magnet 117a faces the magnet attracting portion 107d in the optical axis direction.

In the state shown in FIG. 6C, the magnetic attractive force acting on the biasing magnet 117a is F2, and the magnetic attractive force F2 is divided into an X-direction component (component force) Fx2 and a Z-direction component (component force) Fz2. Divided. The magnetic attractive force Fz2 satisfies the following relationship, where the magnetic attractive force in the Z direction acting on the biasing magnet 117a necessary for design is Fd.
Fd ≦ Fz2 <F1 = F0
It should be noted that the value of Fd is such that when a force acting in the direction opposite to the magnetic attractive force is received due to impact or the like, the shift barrel 102 does not float with respect to the base plate 101 and the balls 111a, 111b, and 111c do not fall off. Value. For example, if the shift barrel 102 does not float even when 4G acceleration is applied from the outside, the weight of the movable part including the shift barrel 102 is M, and the gravitational acceleration is G.
3 x Fd = 4 x M x G
When the shift amount X of the shift barrel 102 satisfies the following relationship, the biasing force in the Z direction of the shift barrel 102 necessary for design is ensured, and the reliability of the image blur correction device 100 is increased.
0 <X ≦ X2
FIG. 6D shows a state in which the shift barrel 102 is shifted by X3 from the reference position. The magnetic attractive force acting on the biasing magnet 117a is F3, and the magnetic attractive force F3 is divided into an X direction component (component force) Fx3 and a Z direction component (component force) Fz3. The magnetic attractive force Fz3 satisfies the following relationship with respect to the magnetic attractive force Fd described above.
Fz3 <Fd
In this case, when a force in the direction opposite to the magnetic attraction force is received due to an impact or the like, the shift barrel 102 may float with respect to the base plate 101, and the balls 111a, 111b, and 111c may drop out. Reliability is lowered.

As described above, the shiftable range in the plane perpendicular to the optical axis of the shift barrel 102 is limited, and the range is a circle having a radius (R2-R1) with the reference position as the center. When the shift barrel 102 is shifted, the urging magnet 117a also moves together, and the maximum value of this movement amount is represented by (R2-R1). The radius R1 of the outer periphery of the protrusion 101a of the base plate 101, the radius R2 of the inner periphery of the opening 102d of the shift barrel 102, the radius R3 of the biasing magnet 117a, and the radius R4 of the magnet attracting portion 107d are as follows: Satisfy the relationship.
R2-R1 <R4-R3
At this time, even if the shift barrel 102 is shifted to an arbitrary position within the shiftable range, the magnetic attraction force of the X direction component that becomes the driving load of the shift barrel 102 is not generated, and the image blur correction device 100 is consumed. Electric power can be reduced.

R1, R2, R3 and R4 may satisfy the following relationship.
R2-R1 <R4 + R3
At this time, even if the shift barrel 102 is shifted to an arbitrary position within the shiftable range, the biasing force in the Z direction of the shift barrel 102 necessary for the design is ensured. Is expensive.

Further, when the shift amount X of the shift barrel 102 is within the following range, the magnetic attraction force of the X direction component that becomes the driving load of the shift barrel 102 is not generated, and the power consumption of the image blur correction device 100 is reduced. it can.
0 <X <X1 (= R4-R3)
Next, the layout of each member described above when viewed in the optical axis direction (when viewed from the second direction) will be described with reference to FIG.

  In the present embodiment, the biasing magnets 117a, 117b, and 117c are disposed outside the balls 111a, 111b, and 111c (positions away from the optical axis) when viewed in the optical axis direction. More specifically, the centers of the biasing magnets 117a, 117b, and 117c are positioned inside the triangle that is a polygon connecting the balls 111a, 111b, and 111c (the centers thereof).

  Further, the biasing magnets 117a, 117b, and 117c, the balls 111a, 111b, and 111c, the drive magnets 105a, 105b, 105c, and 105d, and the guide bar 112 are arranged in a ring-shaped region on the base plate 101 excluding the correction lens 13. ing.

  The biasing magnets 117a, 117b, and 117c are arranged at three intersections of a circle B centered on the position of the optical axis and straight lines L1, L2, and L3 that are equally spaced in the circumferential direction. For this reason, the resultant force of the three magnetic attractive forces generated by the biasing magnets 117a, 117b, and 117c, that is, the action position of the biasing force of the shift barrel 102 is a polygon connecting the balls 111a, 111b, and 111c (center thereof). (Triangle) Located inside T. More specifically, it matches the position of the optical axis.

  The balls 111a, 111b, and 111c that support the shift barrel 102 are arranged at the intersections of a circle A centered on the position of the optical axis and straight lines L1, L2, and L3 that are equally spaced in the circumferential direction. For this reason, the center of gravity of the triangle T connecting the balls 111a, 111b, and 111c (centers thereof) coincides with the position of the optical axis, that is, the position where the urging force of the shift barrel 102 is applied. Therefore, it is unlikely that the shift barrel 102 is tilted with respect to the base plate 101 due to an external impact or the like, and the biasing magnets 117a, 117b, and 117c and the magnet attracting portions 107d, 107e, and 107f are attracted, and image blur correction is performed. The reliability of the device 100 is increased.

  Further, the urging force of the shift barrel 102 acts equally on the balls 111a, 111b, and 111c. That is, the pressures between the balls 111a, 111b, and 111c and the ball rolling portions 107a, 107b, and 107c of the first yoke 107 are the same. Similarly, the pressures between the balls 111a, 111b, and 111c and the sub plates 109a, 109b, and 109c are the same. Therefore, it is unlikely that a large pressure is generated only on the surface where the specific ball and the ball are in contact with each other and the durability of the ball is reduced. This also increases the reliability of the image blur correction apparatus 100. Further, since the friction is increased only on the surface where the specific ball and the ball come into contact with each other, and the possibility that the driving load of the shift barrel 102 is increased is low, the power consumption of the image blur correction apparatus 100 is reduced and the driving characteristics are reduced. Can be improved.

  The drive magnets 105a and 105b are disposed in a region sandwiched between the straight line L1 and the straight line L2, and do not overlap the biasing magnets 117a, 117b, and 117c and the balls 111a, 111b, and 111c in the optical axis direction. The drive magnets 105c and 105d are disposed in a region sandwiched between the straight line L1 and the straight line L3, and do not overlap with the biasing magnets 117a, 117b, and 117c and the balls 111a, 111b, and 111c in the optical axis direction. Therefore, the thickness of the image shake correction apparatus 100 in the optical axis direction can be reduced, and the image shake correction apparatus 100 can be downsized.

  The extending portion 112a in the X direction of the guide bar 112 is disposed between the ball 111b and the biasing magnet 117b, and the extending portion 112b in the Y direction is between the ball 111c and the biasing magnet 117c. Is arranged. The ball 111b and the biasing magnet 117b are disposed between the guide bar sliding portions 101e and 101f of the shift lens barrel 102. The ball 111c and the biasing magnet 117c are the guide bar sliding portion 101b of the base plate 101. , 101c. The guide bar 112, the guide bar sliding portions 101e, 101f, and the guide bar sliding portions 101b, 101c do not overlap with the biasing magnets 117a, 117b, 117c and the balls 111a, 111b, 111c in the optical axis direction. Also by this, the thickness of the image shake correction apparatus 100 in the optical axis direction can be reduced, and the image shake correction apparatus 100 can be downsized.

  In this embodiment, the biasing magnets 117a, 117b, and 117c and the balls 111a, 111b, and 111c are arranged at equal intervals around the optical axis (circumferential direction), but may be arranged at irregular intervals in the circumferential direction. Good. Further, the distances from the respective optical axes of the biasing magnets 117a, 117b, and 117c may be made different, or the distances from the respective optical axes of the balls 111a, 111b, and 111c may be made different.

  Further, in this embodiment, the biasing magnets 117a, 117b, and 117c and the balls 111a, 111b, and 111c are arranged in the same phase in the circumferential direction, but the phases may be different from each other. For example, these may be alternately arranged in the circumferential direction.

  Next, the layout of the image shake correction apparatus 200 according to the second embodiment of the present invention when viewed in the optical axis direction will be described with reference to FIG. In the first embodiment, the biasing magnets 117a, 117b, and 117c are disposed outside the balls 111a, 111b, and 111c when viewed in the optical axis direction. On the other hand, in this embodiment, the biasing magnets 117a, 117b, and 117c are arranged on the inner side (position close to the optical axis) than the balls 111a, 111b, and 111c when viewed in the optical axis direction. More specifically, the biasing magnets 117a, 117b, and 117c are positioned outside the polygon (triangle) T connecting the balls 111a, 111b, and 111c (centers) in the optical axis direction view. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.

  In this embodiment, the biasing magnets 117a, 117b, and 117c are arranged at the intersections of a circle B centered on the position of the optical axis and straight lines L1, L2, and L3 that are equally spaced in the circumferential direction. For this reason, the resultant force of the three magnetic attractive forces generated by the biasing magnets 117a, 117b, and 117c, that is, the action position of the biasing force of the shift barrel 102 is a polygon connecting the balls 111a, 111b, and 111c (center thereof). (Triangle) Located inside T. More specifically, it matches the position of the optical axis. The balls 111a, 111b, and 111c that support the shift barrel 102 are arranged at the intersections of a circle A centered on the position of the optical axis and straight lines L1, L2, and L3 that are equally spaced in the circumferential direction. For this reason, the center of gravity of the triangle T connecting the balls 111a, 111b, and 111c (centers thereof) coincides with the position of the optical axis, that is, the position where the urging force of the shift barrel 102 is applied. In this embodiment, unlike the first embodiment, the diameter of the circle A is larger than the diameter of the circle B.

  FIG. 9 schematically shows a cross section of the shift barrel 102 and the first yoke 107 cut by a plane including the straight line L1 and the optical axis. Ra is the radius of the circle A and corresponds to the distance from the optical axis of the balls 111a, 111b, and 111c. Rb is the radius of the circle B and corresponds to the distance from the optical axis of the biasing magnets 117a, 117b, and 117c. Fa, Fb, and Fc indicate magnetic attractive forces generated by the biasing magnets 117a, 117b, and 117c, respectively.

Each member in FIG. 9 is arranged such that the gaps between the biasing magnets 117a, 117b, and 117c and the magnet attracting portions 107d, 107e, and 107f of the first yoke 107 are the same distance. At this time, the magnetic attractive forces Fa, Fb, and Fc are equal to each other, and the rotational moment I0 of the shift barrel 102 centered on the position of the optical axis (denoted as the optical axis center in the drawing) is expressed as the following equation. Is done.
I0 = Fa × Rb−Fb × Rb / 2−Fc × Rb / 2 = 0
That is, the shift barrel 102 does not generate a rotational force around the optical axis.

  FIG. 10 shows the relationship between the gap and the magnetic attractive force. From this figure, it can be seen that the magnetic attractive force increases exponentially as the gap becomes smaller.

  The sensitivity of the magnetic attraction force to the gap, that is, the magnitude of the change in the magnetic attraction force relative to the change in the gap is increased by increasing the biasing magnet or changing the biasing magnet material to a material that generates more magnetic force. It can be made small by doing. However, the former leads to an increase in the size of the device, and the latter material change has a limit, so the gap sensitivity of the magnetic attractive force must be increased.

  For this reason, if only the gap between the specific energizing magnet and the magnet attracting portion becomes small due to external impact, component dimensional error, mounting error, etc., the balance of the magnetic attractive force is lost. As a result, there is a possibility that the specific energizing magnet and the magnet attracting part are attracted, and the shift barrel 102 is inclined and cannot be driven.

Here, for example, consider a case where only the gap between the biasing magnet 117a and the magnet attracting portion 107d is smaller than the others. Since the gap becomes smaller, the magnetic biasing force Fa becomes larger than Fb and Fc, and a rotational moment is generated by the biasing magnet 117a. The rotational moment I1 of the shift barrel 102 around the optical axis is expressed by the following equation.
I1 = Fa × Rb−Fb × Rb / 2−Fc × Rb / 2> 0
That is, a rotational force represented by M in the figure is generated in the shift barrel 102.

  However, in this embodiment, the balls 111a, 111b, and 111c that support the shift barrel 102 in the optical axis direction are arranged on the outer peripheral side (position farther from the optical axis) than the biasing magnets 117a, 117b, and 117c. Has been. For this reason, even if the rotational force M acts on the shift barrel 102, the gap between the urging magnet 117a and the magnet attracting portion 107d is not further reduced by the presence of the ball 111a, and they are not attracted. Therefore, there is no possibility that the shift barrel 102 is tilted and cannot be driven, and the reliability of the image blur correction apparatus 200 is increased.

  In each of the embodiments described above, the case where the correction lens 13 that is an optical element is shifted for image blur correction has been described. However, an imaging element such as a CCD sensor or a CMOS sensor that photoelectrically converts an optical image is provided on the light receiving surface. You may make it shift to a parallel direction.

  In each of the above embodiments, the case where a ball is used as the support member has been described. However, a support member other than the ball may be used. For example, a protrusion as a support member extending from one member to the other member of the shift barrel and the base plate may be provided, and the tip of the protrusion may be in contact with the other member. In this case, it is preferable that the tip of the protrusion is formed in a spherical shape to reduce the friction between the protrusion and the other member that is generated when the shift barrel is shifted.

  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.

A small and highly reliable image blur correction apparatus can be provided.

13 Correction lens 100 Image shake correction device 101 Base plate 102 Shift lens barrel 107 First yoke 111a, 111b, 111c Ball 117a, 117b, 117c Energizing magnet

Claims (7)

A base member;
A movable member that holds an optical element or an imaging element and is movable in a first direction with respect to the base member;
At least three support members for positioning the movable member with respect to the base member in a second direction orthogonal to the first direction;
A plurality of magnet members provided on one of the base member and the movable member;
A magnetic member that is provided on the other member of the base member and the movable member and that exerts a magnetic attractive force in the second direction between the magnetic member and the magnet member;
When viewed from the second direction, the action position of the resultant magnetic attraction force between the plurality of magnet members and the magnetic member is inside the polygon connecting the at least three support portions. An image blur correction apparatus characterized by that.   When viewed from the second direction, the position of the resultant force in a state where the movable member is located at a reference position that is not moved in the first direction with respect to the base member is the center of gravity of the polygon. The image blur correction device according to claim 1, wherein   3. The image blur correction device according to claim 1, wherein when viewed from the second direction, centers of the plurality of magnet members are located inside the polygon. 4.   The entire movable range of the movable member in the first direction is such that at least a part of the magnet member faces the magnetic member in the second direction. The image blur correction device according to claim 1.   5. The image blur correction apparatus according to claim 1, wherein the support member is a ball disposed between the base member and the movable member. 6. An electromagnetic actuator for moving the movable member in the first direction;
6. The image blur correction apparatus according to claim 1, wherein the electromagnetic actuator uses the magnetic member as a yoke that forms a part of a magnetic path. 7. An optical apparatus comprising the image blur correction device according to claim 1.