JP2010210908A - Shake correction device and optical equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shake correction device that achieves suitable shake correction. <P>SOLUTION: The shake correction device includes: a first member (62) that is equipped with optical parts (34) for correcting image blur; a second member (52) that supports the first member to be relatively movable; and driving parts (82 and 86) that have magnets (64 and 66) provided in one of the first member and the second member and generating magnetic force, and coils (54, 56, 110 and 120) having a conductor (94), where current flows, and provided in the other of the first member and the second member, and generate driving force for relatively moving the first member and the second member. In the coil, the density of the conductor changes in a driving force generating direction of the driving part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a shake correction apparatus and an optical apparatus.

  As a shake correction apparatus that can suppress blurring of a captured image due to camera shake or the like, for example, there is a shake correction apparatus that moves a correction lens or an image sensor in accordance with detected camera shake. Further, as a driving means for driving the correction lens or the like, there is known one equipped with a so-called voice coil motor (VCM) that uses an electromagnetic action generated between a coil and a magnet (see Patent Document 1, etc.). .

  However, the voice coil motor mounted on the shake correction apparatus according to the prior art tends to increase the attenuation of the driving force as the relative movement amount of the coil and the magnet increases. In addition, in a shake correction apparatus that performs movement control of a correction lens or the like in an open loop, the attenuation of the driving force leads to a decrease in control accuracy, and the vibration isolation performance is reduced in a region where the relative movement amount of the coil and the magnet is large. have.

Japanese Patent Laid-Open No. 11-288015

  The present invention has been made in view of such a situation, and an object thereof is to provide a shake correction device capable of performing a preferred shake correction.

In order to achieve the above object, a shake correction apparatus according to the present invention includes:
A first member (62) provided with an optical component (34) for correcting image blur;
A second member (52) for supporting the first member in a relatively movable manner;
A magnet (64, 66) that is provided in one of the first member and the second member and generates a magnetic force, and a conductor (94) through which a current flows is provided in the other of the first member and the second member. Including a coil (54, 56, 110, 120) and a drive unit (82, 86) for generating a drive force for relative movement between the first member and the second member,
The coil is characterized in that the density of the conductor changes in the driving force generation direction of the driving unit.

  Further, for example, in the coil, the change in the density of the conductor in the driving force generation direction of the driving unit may be larger than the change in the density of the conductor in a direction intersecting the driving force generation direction of the driving unit. .

Further, for example, the coil may include a first region (114, 124, 128) and a second region (116, 126) having a higher density of the conductor than the first region,
The density of the conductor in the second region may be twice or more the density of the conductor in the first region.

  Further, for example, the coil may be ring-shaped, and the first region may be provided closer to the center (100, 112, 122) of the ring than the second region.

  For example, the conductor of the coil may be a circuit pattern formed on a circuit board.

  Further, for example, the shake correction apparatus according to the present invention includes a control unit that controls the driving unit to correct image blur without using information on a relative position between the first member and the second member. (74) may be included.

  For example, the optical component may be at least one of an optical system that transmits light and an imaging unit that captures an image of light.

  An optical apparatus according to the present invention includes the shake correction apparatus described in any one of the above.

  In the above description, in order to explain the present invention in an easy-to-understand manner, the description is made in association with the reference numerals of the drawings showing the embodiments. However, the present invention is not limited to this. The configuration of the embodiment described later may be improved as appropriate, or at least a part of the configuration may be replaced with another component. Further, the configuration requirements that are not particularly limited with respect to the arrangement are not limited to the arrangement disclosed in the embodiment, and can be arranged at a position where the function can be achieved.

FIG. 1 is a schematic diagram of a camera including a shake correction apparatus according to an embodiment of the present invention. 2 is an exploded perspective view of a shake correction unit provided in the camera shown in FIG. FIG. 3 is a block diagram illustrating a controller that controls the blur correction unit illustrated in FIG. 2. FIG. 4 is a cross-sectional view of a main part of the blur correction unit shown in FIG. Fig.5 (a) is an expanded sectional view showing arrangement | positioning of the magnet and coil shown in FIG. 4, FIG.5 (b) is a top view of a coil. FIG. 6 is a schematic cross-sectional view showing the density distribution of the conductor of the coil shown in FIG. FIG. 7 is a schematic cross-sectional view showing the density distribution of the conductors of the coil provided in the shake correction unit according to the second embodiment of the present invention. FIG. 8 is a schematic cross-sectional view showing the density distribution of the conductors of the coil provided in the shake correction unit according to the third embodiment of the present invention. FIG. 9 is a diagram illustrating the relationship between the magnetic flux density around the coil and the current flowing through the coil in the shake correction unit according to the first embodiment of the present invention. FIG. 10 is a diagram illustrating the relationship between the magnetic flux density around the coil and the current flowing in the coil in the shake correction unit according to the second embodiment of the present invention. FIG. 11 is a diagram illustrating the relationship between the magnetic flux density around the coil and the current flowing in the coil in the shake correction unit according to the third embodiment of the present invention. FIG. 12 is a graph showing the relationship between the relative movement amount of the blur correction unit and the driving force of the voice coil motor. FIG. 13 is a schematic cross-sectional view showing the density distribution of the conductors of the coil provided in the shake correction unit according to the reference example of the present invention.

First Embodiment FIG. 1 is a schematic view of a camera including a shake correction apparatus according to an embodiment of the present invention. The camera 10 includes a lens barrel portion 27 provided with a lens and the like, and a camera body portion 11 provided with an image sensor 15 and the like. In the camera 10 shown in FIG. 1, the lens barrel 27 and the camera body 11 are integrated, but the optical apparatus provided with the shake correction device according to the present embodiment is not limited to this. For example, a camera body, a lens barrel that can be attached to and detached from the camera body, binoculars, a telescope, a camera-equipped mobile phone, and the like may be used.

  1 includes a body CPU 12, an image sensor 14, a signal processing circuit 16, an EEPROM 18, a release switch 20, a recording medium 22, an AF sensor 24, a rear liquid crystal 26, and the like. The lens barrel 27 is provided with a lens group such as a blur correction lens group 34, a focus lens group 38, and a zoom lens group 42, a drive mechanism for driving these optical components, and the like.

  The body CPU 12 controls the entire camera 10 such as shooting preparation operations such as zooming and focusing, and exposure operations. For example, when a signal is input from the release switch 20, the body CPU 12 controls the focus lens group driving mechanism 40 provided in the lens barrel portion 27 based on information from the AF sensor 24 to perform autofocus. Can do.

  The image sensor 14 is a solid-state image sensor such as a CCD or CMOS. The image sensor 14 is driven and controlled by an image sensor drive circuit (not shown), photoelectrically converts light incident on the image sensor 14 via the lens barrel 27, and outputs an image signal to the signal processing circuit 16. . The signal processing circuit 16 performs noise processing, A / D conversion, and the like on the image signal input from the image sensor 14. The recording medium 22 is controlled by the body CPU 12 and stores image data and the like based on the image signal from the image sensor 14.

  Further, a rear liquid crystal 26 is provided on the rear surface of the housing of the camera body 11. The body CPU 12 can cause the rear liquid crystal 26 to display a through image based on the image signal from the image sensor 14, image data stored in the recording medium 22, and the like.

  The zoom lens group 42 provided in the lens barrel portion 27 moves along the optical axis α of the camera 10 when adjusting the magnification of the camera 10. The zoom drive mechanism 44 moves the zoom lens group 42 and the like according to a control signal from the body CPU 12 and adjusts the magnification of the camera 10. The focus lens group 38 moves along the optical axis α of the camera 10 when adjusting the focus of the camera 10. The focus driving mechanism 40 adjusts the focus of the camera 10 by moving the focus lens group 38 and the like according to a control signal from the body CPU 12. The shutter / aperture unit 30 is driven by a shutter / aperture drive mechanism 32 to control the exposure time and the exposure amount.

  The lens barrel 27 includes a blur correction lens group 34 for correcting image blur due to camera shake or the like. The blur correction lens group 34 is held so as to be movable in a direction orthogonal to the optical axis α of the camera 10. The shake correction driving mechanism 36 receives the control signal from the body CPU 12 and drives the shake correction lens group 34.

  The body CPU 12 controls the blur correction drive mechanism 36 based on the angular velocity signal from the gyro sensor 28 provided in the lens barrel portion 27. The body CPU 12 can adjust the control amount and the like using the gain value of the gyro sensor 28 input from the EEPROM 18 when controlling the shake correction drive mechanism 36.

  FIG. 2 is an exploded perspective view of a shake correction unit 50 that is a main part of the shake correction mechanism drive mechanism 36 shown in FIG. As shown in FIG. 2, the shake correction unit 50 includes a fixed unit 52 and a movable unit 62 arranged along the direction of the optical axis α.

  Further, the fixed portion 52 and the movable portion 62 are arranged in the order of the fixed portion 52 and the movable portion 62 from the imaging element 14 side shown in FIG. 1 toward the lens side such as the zoom lens group 42. In the camera 10 according to the present embodiment, the direction from the imaging element 14 side toward the lens side such as the zoom lens group 42 along the optical axis α is described as the positive direction of the optical axis α.

  The fixing portion 52 shown in FIG. 2 includes a base member 53, a first coil 54, a second coil 56, and a steel ball 58. The base member 53 has a substantially disk shape in which a hole is formed near the center. The hole formed in the central portion allows the light transmitted through the vibration reduction lens group 34 to pass toward the negative direction side of the optical axis α (image sensor 14 side (see FIG. 1)). The base member 53 is disposed such that the main surface 53a of the base member 53 is substantially orthogonal to the optical axis α.

  A first coil 54 and a second coil 56 are attached to the base member 53. The first coil 54 and the second coil 56 are electrically connected to a driver 72 shown in FIG. The body CPU 12 (FIG. 1) can control the value of current flowing through the first coil 54 and the second coil 56 via the controller 74 and the driver 72.

  The base member 53 is formed with a plurality of spring hooks 60. As shown in FIG. 2, the spring hooking portion 60 is engaged with an end portion of a biasing spring 68 that biases the entire movable portion 62 toward the fixed portion 52. Further, three steel balls 58 are disposed between the base member 53 of the first fixed portion 52 and the lens holding frame 63 of the movable portion 62. The steel ball 58 is held in a state of being sandwiched between the base member 53 and the lens holding frame 63. Since the lens holding frame 63 is held in such a manner as to be pressed against the base member 53 with the steel ball 58 interposed therebetween, it can move in parallel with the base member 53 with a low frictional force.

  The movable unit 62 includes a lens holding frame 63 that holds the blur correction lens group 34, a first magnet 64, and a second magnet 66. A spring hook 70 is formed on the lens holding frame 63, and the other end of the urging spring 68 is engaged with the spring hook 70. The lens holding frame 63 has two through holes having a substantially rectangular opening. The first magnet 64 and the second magnet 66 are fixed to the lens holding frame 63 so as to close each of the two through holes formed in the lens holding frame 63.

  The first magnet 64 is disposed so as to face the first coil 54 fixed to the base member 53. Accordingly, the first magnet 64 and the first coil 54 constitute a first voice coil motor 82 that moves the lens holding frame 63 in the X-axis direction substantially orthogonal to the optical axis α. On the other hand, the second magnet 66 is disposed so as to face the second coil 56, and moves the lens holding frame 63 together with the second coil 56 in the Y-axis direction orthogonal to the optical axis α and the X-axis. A second voice coil motor 86 is configured.

  The lens holding frame 63 and the blur correction lens group 34 are orthogonal to the optical axis α by two voice coil motors 82 and 86 configured by the first coil 54 and the first magnet 64, and the second coil 56 and the second magnet 66. Can move along the plane.

  The first magnet 64 fixed to the lens holding frame 63 is a surface arranged in parallel to a surface substantially orthogonal to the optical axis α, and has a surface that is two-pole magnetized. The first magnet 64 is arranged so that the polarization direction of the first magnet 64 (the direction indicated by the arrow C) substantially coincides with the X-axis direction. Further, the first magnet 64 has an intermediate portion 88 provided between the N pole portion 84 and the S pole portion 80. The polarization direction of the magnets 64 and 66 means the direction in which the magnets 64 and 66 are polarized when viewed in a plane substantially perpendicular to the optical axis α.

  The second magnet 66 is arranged so that the polarization direction of the second magnet 66 substantially coincides with the Y-axis direction, and has the same configuration as the first magnet 64 except that the arrangement is different from the first magnet 64. The second coil 56 that constitutes the second voice coil motor 86 together with the second magnet 66 is the same as the first coil 54 except that the arrangement is different. Therefore, in the description of the embodiment, the first voice coil motor 82 composed mainly of the first magnet 64 and the first coil 54 will be described, and the description of the second voice coil motor 86 will be omitted.

  FIG. 3 is a block diagram showing the controller 74 and the like that control the blur correction unit 50 shown in FIG. The controller 74 includes a target position term calculation unit 76, an attitude term calculation unit 77, a temperature term calculation unit 78, and an adder.

  When shake correction control is performed, the CPU 12 calculates a control signal based on a detection signal detected by a gyro sensor 28, a thermistor (not shown), or the like. The control signal calculated by the CPU 12 is input to the controller 74. The target position term calculation unit 76, the posture term calculation unit 77, and the temperature term calculation unit 78 of the controller 74 calculate the target position term, posture term, and temperature term in the driving amount of the shake correction lens based on the control signal from the CPU 12. To do. Further, the controller 74 adds the calculated target position term, posture term, and temperature term to calculate the driving amount of the shake correction lens, and outputs it to the driver 72. The driver 72 calculates the value of the current flowing through the coils 54 and 56 (see FIG. 2) provided in the shake correction unit 50 based on the input driving amount, and changes the magnitude of the current flowing through the coils 54 and 56. In this manner, the controller 74 controls the first and second voice coil motors 82 and 86 in order to correct image blur.

  The controller 74 uses the first and second voice coils by so-called open loop control without using information on the relative positions of the lens holding frame 63 including the blur correction lens group 34 shown in FIG. 2 and the base member 53. The motors 82 and 86 are controlled. The shake correction apparatus that drives the shake correction lens group 34 by open loop control does not require a detection unit that detects the relative position of the shake correction lens group 34, and thus is suitable for downsizing the shake correction unit 50. However, the controller provided in the shake correction apparatus is not limited to that shown in FIG. 3, and may be one that controls the blur correction lens group 34 and the like by so-called closed loop control.

  FIG. 4 is a cross-sectional view showing the periphery of the first voice coil motor 82 in the shake correction unit 50 shown in FIG. The first voice coil motor 82 includes a first magnet 64 fixed to the lens holding frame 63 and a first coil 54 fixed to the base member 53, and moves the blur correction lens group 38 in the X-axis direction.

  FIG. 5A is an enlarged sectional view showing the arrangement of the first magnet 64 and the first coil 54 shown in FIG. The first magnet 64 has a coil facing surface 92 that faces the first coil 54. The coil facing surface 92 is formed with an N pole portion 84 that is the N pole of the magnet, an S pole portion 80 that is the S pole of the magnet, and an intermediate portion 88. The intermediate portion 88 is a region having a lower degree of orientation than the N pole portion 84 and the S pole portion 80, and may be magnetized weaker than the N pole portion 84 and the S pole portion 80, or may not be magnetized. Also good.

  A magnetic field is formed by the first magnet 64 around the first coil 54 disposed so as to face the first magnet 64. Since a force is generated when a current is passed through the magnetic field, a driving force that moves the lens holding frame 63 and the blur correction lens 34 between the first coil 54 and the first magnet 64 when a current is passed through the first coil 54. Will occur.

  FIG. 5B is a plan view of the first coil 54 viewed from the positive direction side of the optical axis α. The first coil 54 has an annular shape with the coil center 100 as the center of the ring. FIG. 6 is a cross-sectional view of the first coil 54. As shown in FIG. 6, the first coil 54 includes a conductor 94 through which a current flows, a laminated material 96 composed of an insulator, and a coating material 98. The conductor 94 is a portion through which current flows in the first coil 54, and is made of a highly conductive metal or the like.

  The conductor 94 is continuous while rotating around the coil center 100 along the ring shape of the first coil 54 shown in FIG. 5B, forming a coil. Further, the first coil 54 according to the present embodiment is an air core coil in which the vicinity of the coil center 100 is an air core.

  Further, the first coil 54 includes an N pole facing portion 54a and an S pole facing portion 54b that are disposed substantially parallel to each other with the coil center 100 interposed therebetween in the X-axis direction that is the driving direction. As shown in FIG. 5A, the N pole facing portion 54 a faces the N pole portion 84 of the first magnet 64, and the S pole facing portion 54 b faces the S pole portion 80 of the first magnet 64. is doing. Further, the coil center 100 of the first coil 54 faces the intermediate portion 88 of the first magnet 64.

  When a current is passed through the conductor 94 (FIG. 6) of the first coil 54, a current in the direction opposite to the S pole facing portion 54b flows through the N pole facing portion 54a. However, the direction of the magnetic field formed around the N pole facing portion 54a is substantially opposite to the direction of the magnetic field formed around the S pole facing portion 54b. Therefore, the direction of the force generated by the current flowing through the conductor 94 of the N pole facing portion 54a matches the direction of the force generated by the current flowing through the conductor 94 of the S pole facing portion 54b, and the first voice coil motor 82 is The lens holding frame 63 can be moved in the X-axis direction.

  In the first voice coil motor 82, since the direction of the current flowing through the first coil 54 and the direction of the magnetic field are in the relationship as described above, as shown in FIG. And the relative movement direction (X-axis direction) of the fixed portion 52 and the movable portion 62 by the first voice coil motor 82 substantially coincide with each other.

  As shown in FIG. 6, in the first coil 54 of the first voice coil motor 82, the density of the conductor 94 changes in the relative movement direction (X-axis direction) of the fixed portion 52 and the movable portion 62. That is, the first coil 54 is configured such that the conductor pitch d in the X-axis direction gradually becomes dense from the coil center 100 side toward the coil outer periphery 101 side. Note that the cross-sectional area of the conductor 94 (the cross-sectional area in a cross section orthogonal to the direction of current) is substantially constant.

  The first coil 54 shown in FIG. 6 can be manufactured by patterning the conductor 94 and the laminated material 96 on a circuit board or the like. The conductor 94 of the first coil 54 may be a winding, but may be a circuit pattern formed on a circuit board as in this embodiment. By making the conductor 94 into a circuit pattern formed on the circuit board, as shown in FIG. 6, a coil in which the density of the conductor 94 changes in each part of the coil can be easily manufactured.

  Thus, the first voice coil motor 82 has a density of the conductor 94 in the X-axis direction, which is the direction in which the first voice coil motor 82 generates the driving force and the relative movement direction of the fixed portion 52 and the movable portion 62. Since it changes, the attenuation of the driving force generated by the relative movement can be suppressed. FIG. 9 shows a graph in which the magnetic flux density B around the first coil 54 and the current I flowing through the first coil 54 are plotted with respect to the relative movement direction (X-axis direction) of the fixed portion 52 and the movable portion 62. FIG. 10 also shows the positional relationship of the first magnet 64 and the first coil 54 on the graph.

  A curve 107 represents the magnetic flux density B of the magnetic field generated around the first coil 54 by the first magnet 64. As shown by the curve 107, around the first coil 54, there are a stable region 104 in which the change in the magnetic flux density B in the X-axis direction is relatively small and an attenuation region 102 in which the change in the magnetic flux density B is large in the X-axis direction. It is formed. The stable region 104 opposes the vicinity of the position of the first magnet 64 facing the central portion of the N pole portion 84 (central portion in the polarization direction C) and the central portion of the S pole portion 80 (central portion in the polarization direction C). It is formed near the position. The attenuation region 102 is formed in the vicinity of a position facing the intermediate portion 88 of the first magnet 64.

  A broken line 108 represents the magnitude of the current that flows inside the first coil 54 when a current flows through the conductor 94 of the first coil 54. Since the conductor 94 shown in FIG. 6 is continuous inside the first coil 54, the magnitude of the current flowing through the first coil 54 is such that the conductor pitch d (see FIG. 6) is from the coil center 100 side to the coil outer periphery 101. Affected by narrowing towards the side. That is, as shown in FIG. 9, the current flowing through the first coil 54 is large on the coil outer periphery 101 side and small on the coil center 100 side.

  The driving force of the first voice coil motor 82 is proportional to the product of the magnetic flux density B and the current I. Therefore, the attenuation of the first voice coil motor 82 increases as the N pole and S pole facing portions 54a and 54b of the first coil 54 overlap with the attenuation region 102 where the change in the magnetic flux density B is large. . However, when only the stable region 104 is used, the driving force of the voice coil motor is reduced, and the magnet must be enlarged in order to ensure the driving force, making it difficult to reduce the size of the voice coil motor.

  As shown in FIG. 9, the first voice coil motor 82 has a current I flowing in the overlapping portion while overlapping a part of the N pole and S pole facing portions 54 a and 54 b of the first coil 54 with the attenuation region 102. By reducing the distance, the attenuation due to the relative movement is suppressed while securing the driving force. FIG. 12 shows the relationship between the driving force of the first voice coil motor 82 and the relative movement amount of the fixed portion 52 and the movable portion 62.

  As shown by the solid line in FIG. 12, in the first voice coil motor 82, the attenuation of the driving force is suppressed even when the relative movement amount of the fixed portion 52 and the movable portion 62 increases. Therefore, the shake correction apparatus including the first voice coil motor 82 can control the shake correction lens group 34 with high accuracy. On the other hand, the voice coil motor according to the reference example including the coil 130 (FIG. 13) in which the density of the conductor 94 is substantially uniform has a large attenuation of the driving force as shown by the dotted line in FIG.

  In the first voice coil motor 82 shown in FIG. 9, the length L1 in the X-axis direction of the N pole portion 84 and the S pole portion 80 of the first magnet 64 is opposite to the N pole facing portion 54a of the first coil 54 and the S pole facing. It is preferable that the length 54 is longer than the length L2 of the portion 54b in the X-axis direction. This is because more portions of the first coil 54 can be disposed in the stable region 104. Further, when the movable portion 62 is located at a reference position that is a position where the optical axis of the blur correction lens group 34 can coincide with the optical axis α of the camera, the N-pole facing portions 54a and S of the first coil 54 are positioned. The pole facing portion 54b is preferably located in a region where the change in the magnetic flux density B is as small as possible. In other words, the first voice coil motor 82 has an X-axis between the end of the N pole and S pole portions 84 and 80 on the intermediate portion 88 side and the end of the N pole and S pole facing portions 54a and 54b on the coil center 100 side. An inner margin L3 that is a positional deviation amount in the direction is formed. Also, an outer margin L4, which is the amount of positional deviation in the X-axis direction between the outer periphery side end portions of the N pole and S pole portions 84, 80 and the end portions of the N pole and S pole facing portions 54a, 54b on the coil outer periphery 101 side, is also provided. Is formed.

  In the first voice coil motor 82, the inner margin L3 and the outer margin L4 are designed to substantially coincide with each other, so that the driving force is more attenuated due to the relative movement of the first coil 54 and the first magnet 64. It is effectively suppressed.

  As shown in FIGS. 6 and 9, the change in the density of the conductor 94 in the first coil 54 is symmetric with respect to the coil center 100. As a result, as shown in FIG. 12, the tendency of the driving force to decay is symmetric with respect to the reference position (the origin in FIG. 12), so the blur correction unit 50 including the first voice coil motor 82 Easy to control.

  Furthermore, as shown in FIG. 6, in the first coil 54, the attenuation of the driving force can be suppressed by changing the density of the conductor 94 only in the driving force generation direction (X-axis direction, see FIG. 5). The same effect cannot be obtained with respect to the Y-axis direction and the α-axis direction. Therefore, it is preferable from the viewpoint of downsizing the first coil 54 that the density of the conductor 94 in the Y-axis direction and the α-axis direction is constant or the change in the density of the conductor 94 is smaller than the change in the X-axis direction.

  As shown in FIG. 3, the shake correction apparatus according to the present embodiment controls the movement amount of the blur correction lens group 34 by so-called open loop control. When the movement amount of the blur correction lens group 34 is controlled by open loop control, suppressing the attenuation of the driving force of the voice coil motors 82 and 86 has a significant effect on improving the control accuracy of the blur correction lens group 34. Have Therefore, the shake correction apparatus according to the present embodiment can realize a shake correction apparatus that is small and has a high correction effect.

Second Embodiment FIG. 7 is a cross-sectional view of a first coil 110 provided in a shake correction apparatus according to a second embodiment of the present invention. The shake correction apparatus according to the second embodiment is the same as the shake correction apparatus according to the first embodiment, except that the first coil 110 and the second coil are different from the first coil 54 and the second coil shown in FIG. is there.

  The first coil 110 has an N-pole facing portion 110 a that faces the N-pole portion 84 of the first magnet 64 (FIG. 5) and an S-pole facing portion 110 b that faces the S-pole portion 80 of the first magnet 64. As with the first coil 54 shown in FIG. 6, the first coil 110 is a conductor 94 in the X-axis direction, which is the direction in which the driving force is generated by the voice coil motor and is the relative movement direction of the fixed portion 52 and the movable portion 62. The density of has changed. That is, the first coil 110 shown in FIG. 7 has a first region 114 in which the conductor pitch in the X-axis direction is d1, and a second region 116 in which the conductor pitch in the X-axis direction is d2.

  The conductor pitch d2 of the second region 116 is smaller than the conductor pitch d1 of the first region 114, and the density of the conductor 94 in the second region 116 is greater than the density of the conductor 94 in the first region 114. The density of the conductor 94 in the second region 116 is preferably at least twice the density of the conductor 94 in the first region 114 from the viewpoint of suppressing attenuation of the driving force of the voice coil motors 82 and 86. In addition, as shown in FIG. 7, when the 1st coil 110 is cut | disconnected along the polarization direction (direction shown by arrow C) of a magnet, the 1st area | region 114 and the 2nd area | region 116 appear. In this case, the density of the conductors 72 in the first region 114 can be considered as the sum of the cross-sectional areas of the conductors 74 occupying the cross-sectional area of the first region 114. The second region 116 can be considered in the same manner as the first region.

  Similarly to the first coil 54 according to the first embodiment, the first coil 110 illustrated in FIG. 7 has an annular shape centered on the coil center 112. FIG. 10 shows a graph in which the magnetic flux density B around the first coil 110 and the current I flowing through the first coil 110 are plotted with respect to the X-axis direction. FIG. 10 also shows the positional relationship of the first magnet 64 and the first coil 110 on the graph.

  A curve 107 represents the magnetic flux density B of the magnetic field generated around the first coil 110 by the first magnet 64. A broken line 118 represents the magnitude of the current flowing inside the first coil 110 when a current is passed through the conductor 94 of the first coil 110. As shown in FIG. 7, the density of the conductor 94 in the first region 114 is smaller than the density of the conductor 94 in the second region 116. Therefore, as shown in FIG. 10, the current flowing through the first region 114 of the first coil 110 is smaller than that in the second region 116.

  Since the first region 114 of the first coil 110 is provided closer to the coil center 112 than the second region 116, the first region 114 is frequently located in the attenuation region 102 where the change in the magnetic flux density B in the X-axis direction is large. However, since the current flowing through the first region 114 is smaller than that of the second region 116 as shown in FIG. 10, the voice coil motor including the first coil 110 generates a driving force generated in the attenuation region 102 where the attenuation is increased. Can be suppressed. Therefore, the voice coil motor including the first coil 110 shown in FIG. 7 also attenuates the driving force generated by the relative movement of the fixed portion 52 and the movable portion 62, like the voice coil motors 82 and 86 according to the first embodiment. Can be suppressed. Moreover, the shake correction apparatus including the first coil 110 illustrated in FIG. 7 has the same effect as the shake correction apparatus according to the first embodiment.

Third Embodiment FIG. 8 is a cross-sectional view of a first coil 120 provided in a shake correction apparatus according to a third embodiment of the present invention. The shake correction apparatus according to the third embodiment is the same as the shake correction apparatus according to the first embodiment, except that the first coil 120 and the second coil are different from the first coil 54 and the second coil shown in FIG. is there.

  The first coil 120 has an N pole facing portion 120 a that faces the N pole portion 84 of the first magnet 64 (FIG. 5) and an S pole facing portion 120 b that faces the S pole portion 80 of the first magnet 64. Similar to the first coil 54 shown in FIG. 6, the density of the conductor 94 in the first coil 120 changes in the relative movement direction (X-axis direction) of the fixed portion 52 and the movable portion 62. That is, the first coil 120 shown in FIG. 8 includes a first region 124 whose conductor pitch in the X-axis direction is d1, a second region 126 whose conductor pitch in the X-axis direction is d2, and a conductor pitch in the X-axis direction. And a third region 128 in which d3 is d3.

  The conductor pitch d2 of the second region 126 is smaller than the conductor pitch d1 of the first region 124 and the conductor pitch d3 of the third region 128, and the density of the conductor 94 in the second region 126 is the first and third regions 124, 128. Greater than the density of the conductor 94 in FIG. As described above, the N pole facing portion 120a and the S pole facing portion 120b of the first coil 120 have the second region 126 having a high conductor density between the first and third regions 124 and 128 having a low conductor density. Prepare. The first to third regions 124, 126, and 128 are arranged along the X-axis direction that is the driving direction. It should be noted that the density of the conductor 94 in the second region 126 is at least twice the density of the conductor 94 in the first region 124 and the third region 128 to suppress the attenuation of the driving force of the voice coil motors 82 and 86. It is preferable from the viewpoint.

  Similarly to the first coil 54 according to the first embodiment, the first coil 120 illustrated in FIG. 8 has an annular shape centered on the coil center 122. FIG. 11 shows a graph in which the magnetic flux density B around the first coil 120 and the current I flowing through the first coil 120 are plotted with respect to the X-axis direction. FIG. 11 also shows the positional relationship of the first magnet 64 and the first coil 120 on the graph.

  A curve 107 represents the magnetic flux density B of the magnetic field generated around the first coil 120 by the first magnet 64. A broken line 129 represents the magnitude of the current that flows inside the first coil 120 when a current flows through the conductor 94 of the first coil 120. As shown in FIG. 8, the density of the conductor 94 in the first region 124 and the third region 128 is smaller than the density of the conductor 94 in the second region 126. Therefore, as shown in FIG. 11, the current flowing through the first region 124 and the third region 128 of the first coil 120 is smaller than that in the second region 126.

  Since the first region 124 of the first coil 120 is provided closer to the coil center 112 than the second region 126, the first region 124 is frequently located in the attenuation region 102 where the change in the magnetic flux density B is large in the X-axis direction. Further, as shown in FIG. 11, the length L2 in the X-axis direction of the N-pole facing portion 54a and the S-pole facing portion 54b in the first coil 120 is longer than the first coil 54 according to the first embodiment. The outer margin L4 of one coil 120 is smaller than the first coil 54 according to the first embodiment. For this reason, the third region 128 of the first coil 120 is formed outside the stable region 104 (in a direction away from the coil center 122), and is located in a region where the change in the magnetic flux density B in the X-axis direction is relatively large. The frequency is high.

  However, the current I flowing through the first region 124 and the third region 128 is smaller than that of the second region 126 as shown in FIG. Therefore, the driving force generated in a region other than the stable region 104 is suppressed. For this reason, in the voice coil motor including the first coil 120, the ratio of the driving force generated in the stable region 104 to the driving force of the entire voice coil motor increases. Therefore, the voice coil motor provided with the first coil 120 shown in FIG. 8 also attenuates the driving force generated by the relative movement of the fixed portion 52 and the movable portion 62, like the voice coil motors 82 and 86 according to the first embodiment. Can be suppressed.

  Further, the length L2 in the X-axis direction of the N-pole facing portion 120a and the S-pole facing portion 120b in the first coil 120 is longer than the length L2 in the first coil 54 according to the first embodiment. Thereby, the 1st coil 120 can generate driving force larger than the 1st coil 54 concerning a 1st embodiment. Therefore, by using a voice coil motor including the first coil 120, the first magnet 64 can be further downsized, and the shake correction apparatus can be downsized. In the first coil 120, the outer margin L4 is smaller than the inner margin L3. As shown in FIG. 10, the fluctuation of the magnetic flux density B tends to be the largest in the region facing the intermediate portion 88 of the first magnet 64. Can be suppressed. Moreover, the shake correction apparatus including the first coil 120 illustrated in FIG. 8 has the same effect as the shake correction apparatus according to the first embodiment.

Other Embodiments In the first to third embodiments described above, the shake correction device that moves the shake correction lens in the direction orthogonal to the optical axis α has been described. However, the shake correction device according to the present invention is not limited to this. For example, a shake correction apparatus that moves an imaging unit that captures an image of light in a direction orthogonal to the optical axis α may be used. In this case, the movable portion is provided with an image sensor or the like instead of the blur correction lens group 34.

  In the first to third embodiments described above, the moving magnet type voice coil motor in which the movable portion is provided with the magnet has been described as an example. However, the shake correction device according to the present invention is not limited to this. A moving coil type voice coil motor in which a coil is provided in the movable part may be provided. In this case, the density of the conductor of the coil provided in the movable part can be changed along the moving direction of the movable part.

DESCRIPTION OF SYMBOLS 50 ... Shake correction part 34 ... Shake correction lens group 52 ... Fixed part 62 ... Movable part 64, 66 ... Magnet 54, 56, 110, 120 ... Coil 82, 86 ... Voice coil motor 114, 124 ... 1st area | region 116,126 ... 2nd area 100, 112, 122 ... Coil center

Claims (8)

A first member provided with an optical component for correcting image blur;
A second member that supports the first member in a relatively movable manner;
A magnet that is provided in one of the first member and the second member and generates a magnetic force; a conductor that has a current flowing therethrough; and a coil that is provided in the other of the first member and the second member; A drive unit that generates a drive force for relative movement between the first member and the second member;
The shake correction apparatus according to claim 1, wherein the coil has a density of the conductor changing in a driving force generation direction of the driving unit. The shake correction apparatus according to claim 1,
The coil is characterized in that a change in density of the conductor in a driving force generation direction of the driving unit is larger than a change in density of the conductor in a direction intersecting the driving force generation direction of the driving unit. apparatus. The shake correction apparatus according to claim 1 or 2, wherein
The coil has a first region and a second region having a higher density of the conductor than the first region,
The shake correction apparatus according to claim 1, wherein a density of the conductor in the second region is at least twice that of the conductor in the first region. The shake correction apparatus according to claim 3, wherein
The shake correction apparatus according to claim 1, wherein the coil has a ring shape, and the first region is provided closer to the center of the ring than the second region. The shake correction apparatus according to any one of claims 1 to 4, wherein
The shake correction apparatus according to claim 1, wherein the conductor of the coil is a circuit pattern formed on a circuit board. The shake correction apparatus according to any one of claims 1 to 5, wherein
A shake correction apparatus comprising: a control unit that controls the drive unit to correct image blur without using information on a relative position between the first member and the second member.   The shake correction apparatus according to any one of claims 1 to 6, wherein the optical component includes at least one of an optical system that transmits light and an imaging unit that captures an image of light. Some shake correction device.   An optical apparatus comprising the shake correction device according to any one of claims 1 to 7.

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