JP2010204157A - Image blur correction device and optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a correction device capable of performing suitable image blur correction. <P>SOLUTION: The image blur correction device has a first member with an optical apparatus to correct image run-out, a second member to relatively movably support the first member, a magnet which is provided on one of the first and second members and generates magnetic force, and a coil which is provided on another member of the first and second members. The image blur correction device includes a drive section to generate driving force to allow relative movement of the first and second members, and a sensor to detect relative location of the first and second members using the magnetic force of the magnet. The magnet has a low magnetization section which is provided between N pole and S pole and more weakly magnetized than the N pole and the S pole. In the low magnetization section, a length of the portion facing the sensor is longer than that of the portion not facing the sensor in terms of the polarization direction of the N pole and the S pole. <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. In addition, as a driving means for driving the correction lens or the like, one using an electromagnetic action generated between the coil and the magnet, or in addition to this, the position of the correction lens or the image sensor is set to a magnetic sensor such as a Hall element. Is known (see Patent Document 1, etc.).

  However, among the shake correction devices that perform position detection with a magnetic sensor, those that use a common magnet for position detection and driving, when trying to reduce the size of the drive unit and position detection device, increase the output of the driving force, There is a problem that it is difficult to achieve both homogenization and high accuracy of position detection.

JP 2007-219388 A

  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, 126, 146) provided with an optical component (34) for correcting image blur;
A second member (52, 124, 144) for supporting the first member in a relatively movable manner;
A magnet (64, 66, 98, 112, 132) provided on one of the first member and the second member and generating a magnetic force, and a coil (54) provided on the other of the first member and the second member. , 56, 120, 140), and a driving unit that generates a driving force for relative movement between the first member and the second member;
A sensor (74, 76, 122, 142) for detecting a relative position between the first member and the second member using the magnetic force of the magnet;
The magnet has a low magnetization part (88, 108, 109, 118, 138) that is provided between the N pole part and the S pole part and is weakly magnetized than the N pole part and the S pole part. And
The low magnetization portion has a length (L1) of a portion facing the sensor as viewed from a polarization direction of the N pole portion and the S pole portion, and a length (L2) of a portion not facing the sensor. It is also characterized by its long length.

  In addition, for example, the low magnetization part includes a first region (88a, 108a, 138a) facing the sensor and a second region (88b, 108b, 1138b) facing the coil, and the polarization When viewed in the direction, the length (L1) of the first region may be longer than the length (L2) of the second region.

  In addition, for example, the low magnetization part includes a first region (118a) facing the sensor and a region (120a) surrounded by the conductor of the coil and a second region (118b) not facing the sensor. And the length (L1) of the first region may be longer than the length (L2) of the second region, as viewed in the polarization direction.

  Further, for example, the magnet may have a first surface (90) facing the sensor and a second surface (92) opposite to the first surface facing the coil.

  Further, for example, the magnet may have a laminated structure in which a first main body portion (110) having the first surface and a second main body portion (111) having the second surface are laminated. .

  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 plan view showing a movable part of the shake correction unit shown in FIG. FIG. 4 is a cross-sectional view of a main part of the blur correction unit shown in FIG. FIG. 5 is an enlarged perspective view showing a magnet provided in a movable part of the shake correction unit shown in FIG. FIG. 6 is an enlarged perspective view showing a modification of the magnet provided in the movable part of the shake correcting part shown in FIG. FIG. 7A is a cross-sectional view illustrating the main part of the shake correction unit of the shake correction apparatus according to the second embodiment of the present invention. FIG. 7B is a plan view showing the shape and arrangement of coils, sensors, and magnets provided in the shake correction unit shown in FIG. 7A. FIG. 8 is an enlarged perspective view showing a magnet provided in the movable part of the shake correction unit shown in FIG. 7A. FIG. 9A is a cross-sectional view illustrating the main part of the shake correction unit of the shake correction apparatus according to the third embodiment of the present invention. FIG. 9B is a plan view showing the shape and arrangement of coils, sensors, and magnets provided in the shake correction unit shown in FIG. 9A. FIG. 8 is an enlarged perspective view showing a magnet provided in the movable part of the shake correction unit shown in FIG. 9A. FIG. 11A is a graph showing the relationship between the relative movement amount of the shake correction unit and the magnetic flux density detected by the detection sensor. FIG. 11B 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. 12 is a diagram illustrating an example of a manufacturing apparatus for manufacturing the magnet illustrated in FIG. 8.

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 part 27 provided with a lens and the like, and a camera body part 11 provided with an image sensor 14 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 drive mechanism 36 receives the control signal from the body CPU 12 and moves 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 first fixed unit 52, a movable unit 62, and a second fixed unit 72 that are arranged along the direction of the optical axis α.

  Further, the first fixed unit 52, the movable unit 62, and the second fixed unit 72 are arranged from the imaging element 14 side shown in FIG. 1 toward the lens side such as the zoom lens group 42, the first fixed unit 52, the movable unit 62, The second fixing portions 72 are arranged in this order. 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 first 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 drive circuit (not shown). 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 drive circuit.

  A plurality of spring hooks 60 are formed on the base member 53. As shown in FIG. 2, the spring hooks 60 bias the entire movable part 62 toward the first fixed part 52. The end of the spring 68 is engaged. 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. Therefore, the first magnet 64 and the first coil 54 constitute a voice coil motor 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 voice coil motor is configured.

  The lens holding frame 63 and the blur correction lens group 34 are placed on a plane orthogonal to the optical axis α by two voice coil motors 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 second fixing portion 72 includes a sensor holding frame 73, a first sensor 74, and a second sensor 76. Two through holes are formed in the sensor holding frame 73. The first sensor 74 and the second sensor 76 are disposed inside the through hole of the sensor holding frame 73. The first sensor 74 is disposed to face the first magnet 64, and the second sensor 76 is disposed to face the second magnet 66.

  The first sensor 74 and the second sensor 76 according to the present embodiment are Hall elements, and can detect a change in the magnetic field accompanying the movement of the magnets 64 and 66. The first sensor 74 detects a change in the magnetic field accompanying the movement of the first magnet 64 in order to detect the position of the lens holding frame 63 in the X-axis direction. On the other hand, the second sensor 76 detects a change in the magnetic field accompanying the movement of the second magnet 66 in order to detect the position of the lens holding frame 63 in the Y-axis direction.

  The first sensor 74 and the second sensor 76 are electrically connected to the FPC 78 fixed to the sensor holding frame 73. Detection signals of the first sensor 74 and the second sensor 76 are input to the body CPU 12 via the FPC 78. The body CPU 12 (FIG. 1) performs shake correction control using position information of the shake correction lens group 34 calculated based on detection signals of the first and second sensors 76 and angular velocity information from the gyro sensor 28 and the like. It can be carried out.

  FIG. 3 is a plan view showing the movable portion 62 of the shake correcting portion 50 shown in FIG. The first magnet 64 fixed to the lens holding frame 63 is disposed so as to be substantially orthogonal to the optical axis α, and has a surface that is dipolarly 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 includes a low magnetization portion 88 that is provided between the N pole portion 84 and the S pole portion 80 and is magnetized weaker than 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. Therefore, in the description of the embodiment, mainly the first magnet and the members related to the first magnet will be described, and the description of the second magnet will be omitted.

  FIG. 4 is a cross-sectional view of the main part showing the periphery of the first magnet 64 in the shake correction unit 50 shown in FIGS. 2 and 3, and FIG. 5 is an enlarged perspective view of the first magnet 64 provided in the shake correction unit 50. FIG. As shown in FIG. 5, the first magnet 64 fixed to the lens holding frame 63 has a substantially rectangular parallelepiped shape. The first magnet 64 has two surfaces magnetized in two poles, and each of the two magnetized surfaces has an N pole portion 84, an S pole portion 80, and a low magnetization. A portion 88 is provided.

  As shown in FIG. 4, the sensor facing surface 90, which is one of the two pole magnetized surfaces of the first magnet 64, faces the first sensor 74 provided in the second fixing portion 72. Yes. The coil facing surface 92, which is the other surface of the two magnetized surfaces of the first magnet 64, faces the first coil 54 provided in the first fixing portion 52.

  Thus, the first magnet 64 is magnetized in two poles and faces the sensor facing surface 90 facing the first sensor 74, and the coil facing surface 92 that is also magnetized in two poles and faces the first coil 54. Have Therefore, the first magnet 64 can generate a magnetic field for moving the movable portion 62 in the X-axis direction around the first coil 54. At the same time, the first magnet 64 can generate a magnetic field around the first sensor 74 for detecting the position of the lens holding frame 63 along the X-axis direction. In addition, since the first magnet 64 in this embodiment is disposed between the first coil 54 and the first sensor 74, the sensor facing surface 90 is provided on the opposite side of the coil facing surface 92.

  The low magnetized portion 88 of the first magnet 64 has a first low magnetized region 88 a provided in the sensor facing surface 90 and a second low magnetized region 88 b provided in the coil facing surface 92. That is, as shown in FIG. 5, the sensor facing surface 90 includes an N pole portion 84, a first low magnetization region 88 a, and an S pole portion 80, the Y axis direction substantially perpendicular to the polarization direction, and each portion 84. , 88a, 80 are provided in a strip shape so that the long side directions thereof coincide with each other. The first low magnetization region 88 a is disposed between the N pole portion 84 and the S pole portion 80, and is sandwiched between the N pole portion 84 and the S pole portion 80 on both sides in the X-axis direction. Similarly to the sensor facing surface 90, the coil facing surface 92 includes an N-pole portion 84, a second low magnetization region 88b, and an S-pole portion 80. The Y-axis direction and the portions 84 and 88b are substantially perpendicular to the polarization direction. , 80 are provided in a strip shape so that the long side directions thereof coincide. Similarly to the first low magnetization region 88a, the second low magnetization region 88b is also disposed between the N pole portion 84 and the S pole portion 80, and the N pole portion 84 is disposed on both sides in the X-axis direction. And the S pole part 80.

  When viewed in a polarization direction substantially coinciding with the X-axis direction, the length L1 of the first low magnetization region 88a of the low magnetization portion 88 is the length of the second low magnetization region 88b as shown in FIG. Longer than L2. That is, as shown in FIG. 4, the low magnetized portion 88 is a portion where the length in the polarization direction at the portion facing the first sensor 74 (sensor facing surface 90) does not face the first sensor 74 (coil facing surface). 92) longer than the length of the polarization direction.

  As a result, even when the first magnet 64 moves relative to the first coil 54 in the X-axis direction as the movable portion 63 moves, the magnetic field around the first coil 54 is less attenuated, and the first coil Attenuation of the driving force of the voice coil motor constituted by 54 and the first magnet 64 is suppressed. Further, the first magnet 64 can form a wider area around the first sensor 74 that satisfies the linearity of the magnetic flux density. Therefore, even when the first magnet 64 moves relative to the first sensor 74 in the X-axis direction as the movable portion 63 moves, the first sensor 74 accurately detects the position of the lens holding frame 63. it can.

  11A and 11B are constituted by the magnetic flux density detected by the first sensor 74 (FIG. 11A), the first coil 54, and the first magnet 64 when the first magnet 64 moves in the X-axis direction. It represents the driving force (FIG. 11B) of the voice coil motor.

  Since the low magnetization portion 88 of the first magnet 64 has a long polarization direction length (L1) on the sensor facing surface 90, the magnetic flux density detected by the first sensor 74 is as shown by a solid line in FIG. Wide range to satisfy linearity. Therefore, the first sensor 74 can detect the position of the blur correction lens group 34 with high accuracy with little linearity error even in a region where the relative movement amount between the movable portion 62 and the second fixed portion 72 is large. However, as indicated by a dotted line in FIG. 11A, in Reference Example 1 in which the length (L1) in the polarization direction on the sensor facing surface 90 is short, the range in which the linearity of the magnetic flux density is satisfied is narrower than in the embodiment. Therefore, in Reference Example 1, the linearity error tends to increase and the position detection error tends to increase in a region where the relative movement amount between the movable part and the first fixed part is large.

  As shown by a solid line in FIG. 11B, the low magnetization portion 88 of the first magnet 64 has a short polarization direction length (L2) in the coil facing surface 92, and therefore the magnetic field generated by the first magnet 64 is strong. The driving force of the voice coil motor constituted by the first coil 54 and the first magnet 64 is large. In addition, since a more uniform magnetic field can be generated around the first coil 54, the voice coil motor constituted by the first coil 54 and the first magnet 64 includes the movable part 62, the first fixed part 52, and the like. Even in the region where the relative movement amount is large, the driving force is less attenuated. However, as shown by a dotted line in FIG. 11B, in Reference Example 2 in which the length (L2) in the polarization direction of the coil facing surface 92 is long, the driving force of the voice coil motor is smaller than that in the embodiment. Further, in a region where the relative movement amount between the movable part and the first fixed part is large, the driving force is greatly attenuated, and it is difficult to drive the voice coil motor with high accuracy.

  In the voice coil motor for shake correction according to the prior art, if the low magnetization area of the magnet is widened to increase the position detection accuracy, the driving force is reduced and the driving force is attenuated. If the low magnetization region of the magnet is narrowed for higher output and homogenization, the position detection accuracy is lowered. Therefore, in the voice coil motor according to the prior art, it is difficult to achieve both high output and homogenization of driving force and high accuracy of position detection while keeping the magnet small. However, the low magnetization part 88 of the first magnet 64 provided in the shake correction part 50 is, as shown in FIGS. 4 and 5, the first low magnetization area 88 a facing the first sensor 74 in the polarization direction. Is longer than the length L2 of the second low magnetization region 88b facing the first coil. Therefore, the shake correction unit 50 according to the present embodiment can achieve both high output of the voice coil motor and homogenization of the driving force and high accuracy of position detection while keeping the first magnet 64 small.

  Further, as shown in FIG. 4, the first magnet 64 includes a sensor facing surface 90 facing the first sensor 74 and a coil facing the first coil 54 on the surface opposite to the sensor facing surface 90. And an opposing surface 92. In the shake correction unit 50 according to the present embodiment, the first sensor 74 and the first coil 54 are disposed with the first magnet 64 interposed therebetween, so that the first magnet 64 is reduced in size in addition to the above-described effects. be able to. Therefore, the shake correction unit 50 according to the present embodiment is suitable for reduction in size and weight.

  The manufacturing method of the first magnet 64 is not particularly limited, but for example, a magnetizing device as shown in FIG. 12 can be used. That is, when magnetizing the magnet material 150, the interval between the magnetized yokes 152 provided between the coil 154 and the magnet material 150 is different between the one surface 150a of the magnet material 150 and the other surface 150b. Interval. When a current is passed through each coil 154 in the state shown in FIG. 12, portions of the magnetic material surfaces 150 a and 150 b that are not in contact with the magnetizing yoke 152 are more than portions that are in contact with the magnetizing yoke 152. Is also weakly magnetized. By magnetizing the magnet material 150 as shown in FIG. 12, it is possible to obtain the magnet 11 in which the length of the low magnetized portion 88 varies depending on the magnet portion.

  FIG. 6 is a perspective view of a magnet 98 provided in a shake correction unit according to a modification of the first embodiment. As shown in FIG. 5, the first and second magnets 64 and 66 used in the blur correction unit 50 may be integrated, but as shown in FIG. May be.

  That is, the magnet 98 has a laminated structure in which a first main body portion 110 having a sensor facing surface 110a and a second main body portion 111 having a coil facing surface 111a are stacked. A first low magnetization region 108 a is provided between the N pole part 104 and the S pole part 100 of the first main body part 110. A second low magnetization region 109 a is provided between the N pole portion 105 and the S pole portion 101 of the second main body portion 111. As shown in FIG. 6, the length of the first low magnetization region 108a is longer than the length of the second low magnetization region 109a when viewed in the polarization direction substantially coinciding with the X-axis direction. In this modification, the low magnetic part 108 having the first low magnetization region 108a and the second low magnetization part 109 having the second low magnetization region 109a are the N pole part 104, This is a region having a lower degree of orientation than 105 and the S pole portions 100 and 101.

  The blur correction unit including the laminated magnet 98 shown in FIG. 6 instead of the first and second magnets 64 and 66 has the same effect as the blur correction unit 50 including the first and second magnets 64 and 66. .

Second Embodiment FIG. 7A is a cross-sectional view of a main part of a shake correction unit 130 according to a second embodiment of the present invention, and shows a peripheral portion of the first magnet 112. In the shake correction unit 130 according to the second embodiment, the first sensor 122 and the second sensor for detecting the position of the lens holding frame 127 are attached to the base member 125 of the first fixing unit 124. There is no fixed part. Further, the shapes of the first magnet 112 and the second magnet provided in the shake correction unit 130 are different from the shapes of the first magnet 64 and the second magnet 66 according to the first embodiment. However, the shake correction unit 130 according to the second embodiment does not have the second fixing unit, the first and second sensors 122 are provided in the fixing unit 124, and the shapes of the first and second magnets 112 are different. Except for differences, this is the same as the shake correction unit 50 according to the first embodiment.

  As shown in FIG. 7A, the first coil 120 and the first sensor 122 are disposed on the base member 125 of the first fixing portion 124. The first magnet 112 is provided on the lens holding frame 127 of the movable portion 126 so as to face the first coil 120 and the first sensor 122.

  FIG. 7B (a) is a plan view of the first coil 120 and the first sensor 122 provided in the base member 125 as viewed from the negative direction side of the optical axis α. As shown in FIG. 7B (a), the first sensor 122 is disposed in the coil hollow portion 120a, which is a region surrounded by the conductor of the first coil 120.

  FIG. 7B (b) is a plan view of the first magnet 112 provided in the lens holding frame 127 as seen from the negative direction side of the optical axis α. The first magnet 112 has a low magnetization portion 118 that is provided between the N pole portion 116 and the S pole portion 114 and is weakly magnetized than the N pole portion 116 and the S pole portion 114. The low magnetized portion 118 has a portion that is wide in the polarization direction at the central portion in the Y-axis direction. The first magnet 112 has a sensor / coil facing surface 112 a that faces the first coil 120 and the first sensor 122.

  FIG. 8 is an enlarged perspective view of the first magnet 112. The first magnet 112 has a substantially rectangular parallelepiped shape, like the first magnet 64 according to the first embodiment. The low magnetized portion 118 of the first magnet 112 is provided on the sensor / coil facing surface 112a, and is provided on the sensor / coil facing surface 112a and the first low magnetized region 118a facing the first sensor 122. A second low magnetization region 118b that faces the coil hollow portion 120a but does not face the first sensor 122. The first low magnetization region 118a corresponds to a portion that is wide in the polarization direction at the center portion in the Y-axis direction in the low magnetization portion 118 shown in FIG. 7B (b).

  That is, when viewed in the polarization direction (substantially coincides with the X-axis direction), the length L1 of the first low magnetization region 118a is equal to the second low magnetization region 118b as shown in FIG. 7B (b) and FIG. Longer than L2. In other words, the low magnetization part 88 is a second low magnetization part in which the length L1 in the polarization direction of the first low magnetization region 118a that is a part facing the first sensor 122 is a part that does not face the first sensor 122. It is longer than the length L2 in the polarization direction of the magnetic region 118b.

  As a result, the first magnet 112 can form a wider area that satisfies the linearity of the magnetic flux density around the first sensor 122. Therefore, even when the first magnet 112 moves along with the movement of the movable portion 126, the first sensor 122 can accurately detect the position of the lens holding frame 127. Further, since the length of the low magnetized portion 118 is short in the portion not facing the first sensor 122, the magnetic field around the first coil 120 even when the first magnet 112 moves with the movement of the movable portion 63. Is attenuated.

  Therefore, the blur correction unit 130 according to the second embodiment, like the blur correction unit 50 according to the first embodiment, can increase the output of the voice coil motor and keep the first magnet 112 and the second magnet small. Both homogenization of driving force and high accuracy of position detection can be achieved. In addition, the shake correction unit 130 according to the present embodiment does not have the second fixing unit because the first sensor 122 and the second sensor are provided in the first fixing unit 124. Therefore, the shake correction unit 130 according to the present embodiment is suitable for downsizing.

Third Embodiment FIG. 9A is a cross-sectional view of a main part of a blur correction unit 148 according to a third embodiment of the present invention, and shows a peripheral portion of the first magnet 132. In the shake correction unit 148 according to the third embodiment, the first sensor 142 and the second sensor for detecting the position of the lens holding frame 147 are disposed adjacent to the first coil 140 and the second coil. The shapes of the first magnet 132 and the second magnet provided in the shake correction unit 148 are different from the shapes of the first magnet 112 and the second magnet according to the second embodiment. However, the shake correction unit 148 according to the third embodiment is different from the shake correction unit 130 according to the second embodiment except that the arrangement of the first and second sensors 122 and the shapes of the first and second magnets 132 are different. It is the same.

  As shown in FIG. 9A, the first coil 140 and the first sensor 142 are disposed on the base member 145 of the first fixing portion 144. The lens holding frame 147 of the movable part 146 is provided with a first magnet 132 so as to face the first coil 140 and the first sensor 142.

  FIG. 9B (a) is a plan view of the first coil 140 and the first sensor 142 provided in the base member 145 as seen from the negative direction side of the optical axis α. As shown in FIG. 9B (a), the first sensor 142 has a B-axis direction relative to the first coil 140 (A that is the driving direction of the voice coil motor constituted by the first coil 140 and the first magnet 132). It is arranged on an extension of the direction substantially perpendicular to the axial direction.

  FIG. 9B (b) is a plan view of the first magnet 132 provided in the lens holding frame 147 as seen from the negative direction side of the optical axis α. The first magnet 132 has a low magnetization portion 138 that is provided between the N pole portion 134 and the S pole portion 136 and is weakly magnetized than the N pole portion 134 and the S pole portion 136. The low magnetized portion 138 has a portion that is wide in the polarization direction at one end in the Y-axis direction. The first magnet 132 has a sensor / coil facing surface 132 a that faces the first coil 140 and the first sensor 142.

  FIG. 10 is an enlarged perspective view of the first magnet 132. The first magnet 132 has a substantially rectangular parallelepiped shape, similarly to the magnet 112 according to the second embodiment. The low magnetized portion 138 of the first magnet 132 is provided on the sensor / coil facing surface 132a, and is provided on the first low magnetized region 138a facing the first sensor 142 and the sensor / coil facing surface 132a. It has the 2nd low magnetization area | region 138b facing the 1st coil 140 and the coil hollow part 140a. The first low magnetization region 138a corresponds to a portion that is wide in the polarization direction near the end in the Y-axis direction in the low magnetization portion 138 shown in FIG. 9B (b).

  That is, when viewed in the polarization direction (substantially coincides with the X-axis direction), the length L1 of the first low magnetization region 138a is equal to the second low magnetization region 138b as shown in FIG. 9B (b) and FIG. Longer than L2. In other words, the low magnetization portion 138 has the second low magnetization portion in which the length L1 in the polarization direction of the first low magnetization region 138a that is a portion facing the first sensor 142 is a portion that does not face the first sensor 122. The length L2 in the polarization direction of the magnetic region 138b is longer.

  Thereby, the first magnet 132 can form a wider area around the first sensor 142 that satisfies the linearity of the magnetic flux density. Therefore, even when the first magnet 132 moves with the movement of the movable portion 147, the first sensor 142 can accurately detect the position of the lens holding frame 147. In addition, in the portion facing the first coil 140 and the coil hollow portion 140a, the length of the low magnetized portion 138 is short, so even if the first magnet 132 moves with the movement of the movable portion 146, the first coil The attenuation of the magnetic field around 140 is suppressed.

  Therefore, the blur correction unit 148 according to the third embodiment, like the blur correction unit 50 according to the first embodiment, increases the output of the voice coil motor while keeping the first magnet 132 and the second magnet small. Both homogenization of driving force and high accuracy of position detection can be achieved.

  Further, the shake correction unit 148 according to the present embodiment does not have the second fixing unit because the first sensor 142 and the second sensor are provided in the first fixing unit 144. Therefore, the shake correction unit 148 according to the present embodiment is suitable for downsizing.

  Furthermore, in the shake correction unit 148 according to the present embodiment, the first sensor 142 is disposed not on the coil hollow portion 140a of the first coil 140 but on the outside of the first coil 140. Therefore, in the shake correction unit 148 according to the third embodiment, the first coil 140 faces only the second low magnetization region 138b and does not face the first low magnetization region 138a. As a result, the shake correction unit 148 needs to make the size of the first magnet 132 larger in the Y-axis direction than the size of the coil 140, but more effectively than the shake correction unit 130 according to the second embodiment. Attenuation of the driving force of the voice coil motor can be suppressed.

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.

50, 130, 148 ... Blur correction unit 34 ... Blur correction lens group 52, 124, 144 ... First fixed unit 62, 126, 146 ... Movable unit 64, 66, 98, 112, 132 ... Magnets 54, 56, 120, 140 ... Coils 74, 76, 122, 142 ... Sensors 88, 108, 109, 118, 138 ... Low magnetization portions 88a, 108a, 109a, 118a, 138a ... First low magnetization regions 88b, 108b, 109a, 118b, 138b ... Second low magnetization region 90 ... Sensor facing surface 92 ... Coil facing surface

Claims (7)

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 provided on one of the first member and the second member and generating a magnetic force; and a coil provided on the other of the first member and the second member, the first member and the second member. A drive unit that generates a drive force for relative movement of the member;
A sensor for detecting a relative position between the first member and the second member using the magnetic force of the magnet;
The magnet includes a low magnetization part that is provided between the N pole part and the S pole part and is magnetized weaker than the N pole part and the S pole part,
The low magnetization portion is characterized in that the length of the portion facing the sensor is longer than the length of the portion not facing the sensor when viewed in the polarization direction of the N pole portion and the S pole portion. Shake correction device. The shake correction apparatus according to claim 1,
The low magnetization portion has a first region facing the sensor and a second region facing the coil, and the length of the first region is the length of the second region when viewed in the polarization direction. A shake correction apparatus characterized by being longer than the length. The shake correction apparatus according to claim 1,
The low magnetized portion has a first region facing the sensor and a second region that is surrounded by the conductor of the coil and does not face the sensor, and when viewed in the polarization direction, The shake correction apparatus according to claim 1, wherein a length of the first region is longer than a length of the second region. The shake correction apparatus according to any one of claims 1 to 3, wherein
The shake correction apparatus according to claim 1, wherein the magnet includes a first surface facing the sensor and a second surface opposite to the first surface facing the coil. The shake correction apparatus according to claim 4, wherein
The shake correction apparatus according to claim 1, wherein the magnet has a stacked structure in which a first main body having the first surface and a second main body having the second surface are stacked. The shake correction apparatus according to any one of claims 1 to 5, wherein
The shake correction apparatus, wherein the optical component is at least one of an optical system that transmits light and an imaging unit that captures an image of light.   An optical apparatus comprising the shake correction device according to any one of claims 1 to 6.

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