JP6511495B2 - Shake correction device - Google Patents

Description

  The embodiment of the present invention relates to a shake correction device for moving a movable portion relative to a fixed portion in a surface direction orthogonal to the alignment direction.

  Conventionally, as a shake correction device, a device that corrects camera shake by moving a movable portion holding a camera lens and an imaging element (optical member) along a plane orthogonal to the optical axis with respect to a fixed portion is known. ing.

  In general, a motion compensation device of this type includes a plurality of balls as spacers disposed between the movable portion and the fixed portion, and a plurality of balls that are pulled toward the fixed portion so as to sandwich the plurality of balls in the optical axis direction. And a voice coil motor (VCM) for moving the movable portion in the surface direction with respect to the fixed portion.

  The VCM usually has a magnet provided on one of the movable part and the fixed part, a coil provided on the other of the movable part and the fixed part, and at least one yoke that forms a magnetic circuit together with the magnet and the coil. The yoke is provided on at least one of the movable portion and the fixed portion.

  A holding mechanism using a magnetic spring instead of providing a plurality of coil springs is known in order to attract and hold the movable portion to the fixed portion. As an example of a magnetic spring, for example, the movable portion is attracted to the fixed portion using a magnetic attraction force between a magnet provided on the movable portion (or fixed portion) and a yoke provided on the fixed portion (or movable portion). It is known to hold a plurality of balls between them. That is, when such a magnetic spring is used, a coil spring becomes unnecessary, and the device configuration can be simplified accordingly.

JP, 2013-88684, A

  However, in a device using this type of magnetic spring, an appropriate size for holding the movable portion on the fixed portion without losing the original function of the yoke forming the magnetic circuit (that is, the function of improving the output of the VCM). It is difficult to obtain magnetic attraction, and it is difficult to satisfy both functions simultaneously.

  Since the yoke usually has the same size as the magnet, when this type of magnetic spring is used, the magnetic attraction force generated with the magnet is larger than the tensile force by the coil spring. For this reason, the force for sandwiching the plurality of balls in the optical axis direction becomes larger than necessary, and the movable portion and the fixed portion are abraded and deteriorated easily by the sliding contact of the balls.

  In addition, when this type of magnetic spring is used, it is necessary to provide a magnet or a yoke in the movable part, and in any case, the movable part becomes heavy, and the power consumption of the VCM becomes large.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to achieve an efficient and stable motion which can attract the movable portion toward the fixed portion with an appropriate force without making the movable portion heavy. An object of the present invention is to provide a correction device.

The shake correction device according to the present embodiment includes a first fixing portion including a magnet, a second fixing portion including a yoke forming a magnetic circuit between the magnet, the first fixing portion, and the second fixing portion. A movable portion disposed between the fixed portion and the coil facing the magnet and the movable portion holding the optical member, and disposed between the movable portion and the first fixed portion, the movable portion being the first fixed portion And a plurality of rolling elements movably supported in a surface direction orthogonal to the alignment direction, and a magnetic attraction force provided between the magnet and the movable member so as to face the magnet, the movable portion constitutes a magnetic spring for generating the restoring force for returning to the previous original position that moves along a first direction aligned magnetic poles of the magnet, the first fixing part said movable part has a plate-shaped magnetic material Ru attracted to, the first hand of the upper Symbol plate-like magnetic bodies The length of greater than a length of the first direction perpendicular to the second direction, the end of the first direction of the plate-shaped magnetic material, before the original to the plate-like magnetic body moves the When the plate-like magnetic body is projected onto the magnet in the state of being positioned, the plate-like magnetic body is located inside the outer peripheral portion of the magnet, and the plate-like magnetic body is the above in the first direction. longer than the width of the coil, for the above Ki磁 electrode and said Oh Rukoto above projected area of the two regions become equal positional relationship.

  According to the present invention, it is possible to provide a shake correction device capable of attracting the movable portion toward the fixed portion with an appropriate force without making the movable portion heavy and capable of performing an efficient and stable operation.

FIG. 1 is a cross-sectional view of a camera according to the embodiment. FIG. 2 is an enlarged cross-sectional view of the anti-vibration unit according to the first embodiment incorporated in the camera of FIG. FIG. 3 is a perspective view of the anti-vibration unit of FIG. 2 as viewed obliquely from the front. FIG. 4 is an exploded perspective view of the anti-vibration unit of FIG. FIG. 5 is an exploded perspective view of the anti-vibration unit of FIG. 3 as viewed obliquely from the rear. 6 is an exploded perspective view of a movable portion of the image stabilization unit of FIG. FIG. 7 is a block diagram of a control system that controls the operation of the image stabilization unit of FIG. FIG. 8 is a front view showing a vibration control unit according to the second embodiment. FIG. 9 is a front view of the anti-vibration unit of FIG. 8 with the yoke removed. FIG. 10 is a front view showing a yoke of the vibration control unit of FIG. 3 by a broken line. FIG. 11 is a partially enlarged cross-sectional view of the anti-vibration unit of FIG. 10 partially cut at F11-F11. FIG. 12 is a front view (a) and a side view (b) showing the relationship between the magnet and the coil of the anti-vibration unit of FIG. FIG. 13 is a diagram showing an intensity distribution of magnetic flux along the driving direction of FIG. FIG. 14 is a diagram showing the intensity distribution of the magnetic flux along the drive orthogonal direction of FIG. FIG. 15 is an operation explanatory view for explaining the behavior of the magnetic body provided in the movable portion of the image stabilization unit of FIG. 3. FIG. 16 is an operation explanatory view for explaining the behavior of the magnetic body provided on the movable portion of the image stabilization unit of FIG. 3 as well as FIG. FIG. 17 is a graph showing the relationship between the amount of movement of the magnetic body shown in FIG. 16 and the restoring force acting on the magnetic body. FIG. 18 is a diagram for describing appropriate dimensions of the magnetic body provided in the movable portion of the vibration isolation unit of FIG. 3. FIG. 19 is a side view of FIG. FIG. 20 is a view showing a modification in the case where a coil is provided on the movable portion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a camera 100 according to the embodiment. In the following description, the direction from right to left in FIG. 1 is referred to as the front, and the opposite is referred to as the rear. Further, an axis coincident with the optical axis O of the camera 100 is taken as a Z axis (an axis in the front-rear direction), and two axes orthogonal to each other along a plane orthogonal to the Z axis are an X axis (horizontal axis) and a Y axis (Axis in the vertical direction).

  The camera 100 includes a lens unit 12, a shutter unit 14, an image stabilization unit 10, a display unit 16 and the like. The camera 100 also has a case 18 in which the plurality of units 12, 14, 10, 16 are arranged in the direction of the optical axis O and accommodated. The image stabilization unit 10 is an example of a drive device and a shake correction device.

  The lens unit 12 forms an image of an object (not shown) on the image pickup element 1 (driven member, optical member) provided in the image stabilization unit 10. The shutter unit 14 controls the time during which the subject is exposed to the imaging device 1 by controlling the opening and closing time of the shutter unit 14. The image stabilization unit 10 moves the imaging element 1 in the plane direction orthogonal to the optical axis O so that the image does not blur even when the camera 100 is vibrated at the time of shooting. The display unit 16 is provided on the back side of the case 18 and displays a digital image photoelectrically converted by the imaging device 1.

The vibration reduction unit 10 according to the first embodiment will be described below with reference to FIGS. 2 to 6.
2 is an enlarged cross-sectional view of the anti-vibration unit 10 of FIG. 1, FIG. 3 is a perspective view of the anti-vibration unit 10 as viewed from the front upper right, and FIG. FIG. 5 is an exploded perspective view of the anti-vibration unit 10 as viewed obliquely from the rear. FIG. 6 is an exploded perspective view of the movable portion of the image stabilization unit 10. As shown in FIG.

  The anti-vibration unit 10 includes a fixed frame 2 (first fixed portion) in which two first magnets 2a and 2b for X axis direction driving and one second magnet 2c for Y axis direction driving are fixed, and X Two first coils 4a and 4b for axial driving, one second coil 4c for Y axis direction driving, and a movable portion 40 in which the imaging device 1 is fixed to the movable frame 4; and 1 such as SPCC and SUS304 And Yoke 6 (a 2nd fixing | fixed part, a 1st yoke, a 2nd yoke) which consists of a sheet of metal plate.

  As shown in FIG. 4, one first magnet 2 a is attached to the upper left corner of the front surface of the substantially rectangular plate-like fixed frame 2. More specifically, the first magnet 2a is attached to the front surface of the fixed frame 2 with an adhesive or the like, sandwiching the two yokes 21 in a state of overlapping each other. The one first magnet 2a is attached to the fixed frame 2 in a posture in which the direction in which the magnetic poles are arranged is parallel to the X axis.

  Similarly, the other first magnet 2b sandwiches the two yokes 21 in the lower left corner of the front surface of the fixed frame 2 (shown below the one first magnet 2a in the figure). It is pasted. The first magnet 2b is also attached to the fixed frame 2 in a posture in which the arrangement direction of the magnetic poles is parallel to the X axis, as in the first magnet 2a.

  Further, the second magnet 2 c is arranged along the lower end of the front surface of the fixed frame 2 in the X axis direction with respect to the first magnet 2 b. The second magnet 2 c is also attached to the front surface of the fixed frame 2 with the two yokes 21 interposed therebetween. Then, the second magnet 2c is attached to the fixed frame 2 in a direction in which the direction in which the magnetic poles are arranged is parallel to the Y axis, that is, the first magnets 2a and 2b are different in the alignment direction of the magnetic poles by 90 degrees. There is.

  As shown in FIGS. 4 and 5, the three coils 4a, 4b and 4c provided on the movable frame 4 are in a state where the vibration isolation unit 10 is assembled with the movable frame 4 facing the fixed frame 2 (for example, FIG. Are laid out at positions facing the three magnets 2a, 2b and 2c of the fixed frame 2, respectively. Each coil 4a, 4b, 4c is housed and arranged in a counterbore (not shown) formed on the rear surface of the plate-like movable frame 4 as shown in the exploded view of FIG. It is fixed by.

  The two first coils 4a and 4b, when the control current is supplied to the respective coils 4a and 4b, cause the movable frame 4 to be fixed to the fixed frame 2 by the electromagnetic induction action between the opposing first magnets 2a and 2b. The movable frame 41 is attached to the movable frame 41 so as to be movable in the X-axis direction (first direction). In addition, when the second coil 4c passes the control current, the movable frame 4 is moved in the Y-axis direction (second direction) with respect to the fixed frame 2 by the electromagnetic induction action between the second coil 4c and the opposing second magnet 2c. It is attached to the movable frame 41 in a direction in which it can be moved. The moving direction of the movable frame 4 can be changed in the reverse direction by changing the direction of the current supplied to the coils 4a, 4b, 4c.

  As shown in FIG. 6, in addition to the above, the imaging element 1, the heat sink 42, the filter assembly 43, the filter holding frame 44 and the like are attached to the movable frame 4. The movable frame 4 has a substantially rectangular attachment opening 41 for attaching the imaging device 1. The imaging element 1 is attached to the attachment opening 41 from the rear side of the movable frame 4. The heat sink 42 is attached in contact with the rear surface of the imaging device 1.

  The filter assembly 43 has a structure in which optical filters such as an optical low pass filter and an infrared cut filter are overlapped in the optical axis direction. The filter holding frame 44 is disposed in front of the filter assembly 43 and fixed to the movable frame 4 by a screw or the like. Thus, the filter assembly 43 is attached to the movable frame 4.

  Further, on the front surface of the movable frame 4, three elongated counterbore portions 41a, 41b and 41c for accommodating and arranging the two first magnetic members 5a and 5b and the one second magnetic member 5c are provided. ing. That is, these three magnetic bodies 5 a, 5 b and 5 c are also movable together with the movable frame 4.

  Counterbore portions 41a and 41b for attaching the two first magnetic members 5a and 5b are provided on the opposite side of the counterbore portions of the first coils 4a and 4b, respectively, and extend in the X-axis direction. That is, the two first magnetic members 5a and 5b also face the two first magnets 2a and 2b on the fixed frame 2 side in the state where the vibration isolation unit 10 is assembled. The two first magnetic members 5a and 5b are extended along the alignment direction of the magnetic poles of the opposing first magnets 2a and 2b, respectively, and the projection area of the first magnets 2a and 2b is the first magnet. It has a size that fits inside the outer periphery.

  On the other hand, the counterbore portion 41c for attaching the second magnetic body 5c is provided on the opposite side of the counterbore portion of the second coil 4c, and is extended in the Y-axis direction. That is, the second magnetic body 5c also opposes the second magnet 2c on the fixed frame 2 side in a state where the vibration isolation unit 10 is assembled. The second magnetic body 5c is also extended along the alignment direction of the opposing magnetic poles of the second magnet 2c, and the size in which the projection area with respect to the second magnet 2c can be accommodated inside the outer peripheral portion of the second magnet Have.

  As shown in FIG. 3, the yoke 6 has a substantially U-shaped structure so as to cover the three magnets 2 a, 2 b and 2 c of the fixed frame 2 in a state where the vibration isolation unit 10 is assembled. The yoke 6 is fastened and fixed to the corresponding boss 22 on the fixed frame 2 side using three screws 6a.

  That is, the yoke 6 of the present embodiment integrally includes the first yoke overlapping the first magnets 2a and 2b and the first coils 4a and 4b, and the second yoke overlapping the second magnets 2c and the second coil 4c. It is connected and functions as a second fixing portion fixed to the fixing frame 2 itself.

  In the present embodiment, as described above, one plate-shaped yoke 6 is directly fixed to the fixed frame 2, but the yoke 6 may be divided into a plurality of pieces. It may be attached to the fixed frame (second fixed part) of

  In any case, the first magnets 2a and 2b, the first coils 4a and 4b, and the yoke 6 move the movable frame 4 in the X-axis direction with respect to the fixed frame 2 (VCM) (first drive Function as a voice coil motor (VCM) (second drive unit) that moves the movable frame 4 in the Y-axis direction with respect to the fixed frame 2 and functions as the second magnet 2c, the second coil 4c, and the yoke 6 Function.

  When assembling the vibration-proof unit 10 of the said structure, it interposes so that three balls 3a, 3b, 3c (rolling body) (refer FIG. 4) may be pinched | interposed between the fixed frame 2 and the movable frame 4. The front surface of the fixed frame 2 and the rear surface of the movable frame 4 are provided with rectangular recesses 32 and 34 (see FIG. 11) for receiving the three balls 3a, 3b and 3c, respectively. , Balls 3a, 3b, 3c do not come off. Bottom plates 33 and 35 (see FIG. 11) are provided at the bottoms of the recesses 32 and 34 for suppressing abrasion between the balls 3a, 3b and 3c, respectively.

  The movable portion 40 is provided movably in a floating state with respect to the fixed frame 2 (and the yoke 6). The movable portion 40 is a fixed frame by the magnetic attraction force acting between the three magnetic members 5a, 5b and 5c provided on the movable frame 4 and the three magnets 2a, 2b and 2c provided on the fixed frame 2. It is energized toward 2. For this reason, the three balls 3a, 3b, 3c are held under pressure by the recess 32 of the fixed frame 2 and the recess 34 of the movable frame 4 by this magnetic attraction force, and function as a spacer between them.

  That is, the first magnetic body 5a and the first magnet 2a function as a first magnetic spring, and the first magnetic body 5b and the first magnet 2b function as a first magnetic spring, and the second magnetic body 5c and the second magnetic body 5c The second magnet 2c functions as a second magnetic spring. The structure and function of the magnetic spring will be described in detail later.

  Since these three sets of magnetic springs are provided at the positions of the VCMs (positions of the magnets 2a, 2b and 2c), the layout is not necessarily good from the relationship with the support position by the three balls 3a, 3b and 3c. It does not. Therefore, in the present embodiment, in addition to these three magnetic springs, one coil spring 7 is attached so as to bridge between the fixed frame 2 and the movable frame 4.

  As shown in FIG. 4, the ball 3 a is provided below the first magnet 2 a in the drawing, the ball 3 b is provided between the first magnet 2 b and the second magnet 2 c, and the ball 3 c is near the coil spring 7. Provided in That is, the three balls 3 a, 3 b, 3 c support the movable frame 4 at three points with respect to the fixed frame 2.

  On the other hand, since the three sets of magnetic springs are disposed at the positions of the VCM as described above, the force for pulling the movable frame 4 toward the fixed frame 2 is relatively weak near the ball 3c. Therefore, in the present embodiment, the coil spring 7 is provided at this position. One end of the coil spring 7 is attached to the movable frame 4, and the other end of the coil spring 7 is attached to the fixed frame 2.

FIG. 7 is a block diagram of a control system that controls the operation of the image stabilization unit 10 having the above-described structure.
The control system of the image stabilization unit 10 includes an X-axis gyro 102 and a Y-axis gyro 104 for detecting the amount of shake of the camera 100, Hall elements 106 and 108 for detecting the position of the imaging device 1 along the XY plane, The image stabilization control circuit 110 calculates a shake correction amount from the detected shake amount and the position in the surface direction, and the actuator drive circuit 112 which supplies a drive current to the coils 4a, 4b and 4c of each VCM according to the calculated shake correction amount. Have.

  As described above, according to the present embodiment, the three magnetic members 5a, 5b and 5c facing the magnets 2a, 2b and 2c separately from the yoke 6 constituting the magnetic circuit of the VCM are used as the movable frame 4 Since it is provided, the function as a magnetic spring can be independently provided separately from the magnetic circuit of the vibration isolation unit 10, and the movable frame 4 can be attracted to the fixed frame 2 with a desired appropriate magnetic attraction force F. . That is, the magnetic attraction force F is set to a desired value by changing the projected area of the three magnetic members 5a, 5b, 5c to the magnets 2a, 2b, 2c, and the thickness and material of each of the magnetic members 5a, 5b, 5c. It can be easily controlled.

  Further, according to the present embodiment, since the movable frame 4 is provided with the magnetic members 5a, 5b and 5c made of relatively small and light metal pieces, the movable portion is movable compared to the case where the movable portion is provided as before. The weight of the part 40 can be reduced, and the power consumption of the VCM can be reduced. Furthermore, according to the present embodiment, the movable frame 4 is moved to the plane direction orthogonal to the optical axis O by the motion compensation operation because a large amount of magnetic spring is used as a mechanism for attracting the movable frame 4 to the fixed frame 2. The force (restoration force along the XY plane direction of the magnetic spring) to return to the original position before moving can be reduced, and the undesired load in the surface direction at the time of vibration correction can be reduced.

  On the other hand, when a holding structure is adopted in which the movable frame 4 is attracted to the fixed frame 2 only by the magnetic spring, a control current having a frequency component that matches the resonance frequency specific to the vibration isolation unit 10 is supplied to the coils 4a, 4b, 4c. In such a case, the movable frame 4 vibrates largely beyond the amplitude intended by the control, which may cause a failure that requires a lot of time to damp the vibration. Therefore, in the present embodiment, the coil spring 7 that mechanically attracts the movable frame 4 to the fixed frame 2 is provided, so that the above-mentioned failure due to resonance can be suppressed by control.

  Further, as described above, when the coil spring 7 is provided to compensate for the magnetic attraction force by the magnetic spring provided only at the position of the VCM, the balance in the XY plane of the force in the Z-axis direction attracting the movable frame 4 to the fixed frame 2 And the anti-vibration unit 10 can be operated stably. Furthermore, by providing the coil spring 7 as well as the magnetic spring, the assemblability of the vibration-proof unit 10 can be improved.

However, the coil spring 7 is not an essential component of the present invention, and the single coil spring 7 can be replaced with a magnetic spring as long as the above-described failure due to the resonance can be eliminated.
FIG. 8 is a front view of the anti-vibration unit 50 according to the second embodiment having no coil spring 7 as viewed from the front along the optical axis O. FIG. 9 is a view from the anti-vibration unit 50 of FIG. It is a front view of the state which removed. Here, components that function in the same manner as the image stabilization unit 10 according to the first embodiment described above are given the same reference numerals, and detailed descriptions thereof will be omitted.

  The vibration isolation unit 50 of the present embodiment has a fourth magnetic spring at the position where the coil spring 7 is attached in the first embodiment. As shown in FIG. 9, the fourth magnetic spring includes an elongated plate-like magnetic body 5d extending in the X-axis direction. The magnetic body 5d is fixed to the front surface of the movable frame 4 in the same manner as the other magnetic bodies 5a, 5b and 5c. Further, on the front surface of the fixed frame 2 facing the magnetic body 5d, a magnet not shown for a magnetic spring is attached. The magnet is provided in a posture in which the direction in which the magnetic poles are aligned is along the X axis.

  Similarly to the other three magnetic springs described above, the fourth magnetic spring also has its magnetic attraction force F by changing the projection area of the magnetic body 5d with respect to the opposing magnet, the thickness in the Z-axis direction, etc. Can be controlled to any desired value.

  As described above, according to the second embodiment, since only the magnetic spring is used as the holding mechanism of the movable portion 4 without using the coil spring 7, the direction along the XY plane given to the movable portion 4 at the time of the shake correction operation Undesired force (force to return the movable portion 4 to the neutral position) can be reduced, and power consumption of the VCM can be reduced.

  Further, according to the present embodiment, since only the magnetic spring is used, the installation space can be reduced as compared with the case where the coil spring 7 is used, the device configuration can be made more compact, and the device can be miniaturized.

  Furthermore, when only the magnetic spring is used as in the present embodiment, the frictional noise that can occur at both ends when using the coil spring 7 can be eliminated, and the convenience for the user can be improved.

  Hereinafter, the structure and function of the magnetic spring in each embodiment described above will be described in more detail with reference to FIGS. 10 and 11. FIG. 10 is a front view of the anti-vibration unit 10 according to the first embodiment as viewed from the front along the direction of the optical axis O. FIG. 11 is a partial view of the anti-vibration unit 10 in F11-F11 of FIG. It is sectional drawing cut | disconnected. Since the three magnetic springs function similarly, only the magnetic spring including the magnetic body 5b will be described as a representative, and the description of the other magnetic springs will be omitted. In FIG. 10, in order to illustrate the position and the direction in the XY plane of the magnetic body 5b in an easily understandable manner, the yoke 6 is shown by a broken line so that it can be seen through.

  As shown in FIG. 11, a ball is provided between the movable frame 4 holding the coil 4b (4a, 4c) and the magnetic body 5b (5a, 5c) and the fixed frame 2 holding the magnet 2b (2a, 2c). 3b (3a, 3c) are provided. The front surface of the fixed frame 2 is provided with a recess 32 for receiving the ball 3 b, and a bottom plate 33 is disposed at the bottom of the recess 32. Further, a concave portion 34 for receiving the ball 3 b is provided on the rear surface of the movable frame 4, and a bottom plate 35 is disposed on the bottom of the concave portion 34.

  The distance between the surface of the bottom plate 33 where the balls 3b make point contact and the front surface of the fixed frame 2 and the distance between the surface of the bottom plate 35 where the balls 3b make point contact and the rear surface of the movable frame 4 are It is set to a value smaller than the diameter of the ball 3b by adding both. Therefore, a gap is formed between the front surface of the fixed frame 2 and the rear surface of the movable frame 4 opposed to each other with the ball 3 b interposed therebetween. By providing such a gap, the movable frame 4 floats with respect to the fixed frame 2 and the movable frame 4 can move along the XY plane. When the movable frame 4 moves in the surface direction with respect to the fixed frame 2, the balls 3 b roll in the recesses 32 and 34.

  On the other hand, the first coil 4b, the first magnetic body 5b, and the yoke 6 are disposed at positions facing the first magnet 2b fixed on the front surface of the fixed frame 2 along the optical axis O direction. In this order, they are arranged to overlap each other separately. The first coil 4b is accommodated and fixed in a counterbore formed on the rear surface of the movable frame 4, and the first magnetic body 5b is provided on the front surface of the movable frame 4 on the opposite side of the first coil 4b. It is accommodated and fixed in the counterbore part 41b. The first coil 4b and the first magnetic body 5b are not in contact with each other. Further, a Hall element 106 for detecting the position of the movable frame 4 in the X-axis direction is fixed to the movable frame 4. The Hall element 106 is provided at the center of the coil 4b.

  As shown in FIG. 10, the first magnetic body 5b extends in the X-axis direction, and extends in the arranging direction of the magnetic poles of the opposing first magnets 2b. Thus, the magnetic attraction force F in the direction shown by the arrow F in FIG. 11, that is, the direction approaching the first magnet 2b, is applied to the first magnetic body 5b fixed to the movable frame 4 so as to face the first magnet 2b. Always works. The magnetic attraction force F acts on the movable frame 4 holding the first magnetic body 5 b, and is a force for holding the movable frame 4 in the direction approaching the fixed frame 2.

  Next, the relationship between the strength of the magnetic spring and the shape (including the layout) of the first magnetic body 5b will be described with reference to FIGS. Although the description here focuses on the magnetic spring including the first magnetic body 5b, it goes without saying that the same is true for the other magnetic springs.

  FIG. 12 (a) is a front view showing the relationship between the first magnet 2b and the first coil 4b, and FIG. 12 (b) is a side view thereof. The first magnet 2 b is fixed to the fixed frame 2, the first coil 4 b is fixed to the movable frame 4, and there is a gap between the two. The movable frame 4 (not shown here) provided with the first coil 4b is connected to the fixed frame 2 (not shown here) provided with the first magnet 2b when a control current flows through the first coil 4b. , In the alignment direction of the magnetic poles. Hereinafter, this direction is referred to as a drive direction. Also, a direction along the XY plane orthogonal to the drive direction is referred to as a drive orthogonal direction.

  The intensity distribution (profile) of the magnetic flux on the front side of the first magnet 2b, that is, on the side where the first coil 4b and the first magnetic body 5b are disposed is different in the drive direction and the drive orthogonal direction. Looking at the intensity distribution of the magnetic flux along the drive direction, that is, the alignment direction of the magnetic poles, as shown in FIG. 13, the direction of the magnetic flux is reversed at the bifurcated position of the two magnetic poles, and the intensity also changes significantly. I understand. On the other hand, looking at the intensity distribution of the magnetic flux along the drive orthogonal direction, it can be seen that, as shown in FIG.

  The first magnetic body 5b according to the present embodiment is extended along the driving direction so as to face the first magnet 2b, and thus is easily influenced by the intensity distribution shown in FIG. As described above, since the direction of the magnetic flux is reversed along the alignment direction of the magnetic poles of the first magnet 2b, the first magnetic body 5b extended in the driving direction and facing the first magnet 2b is also As shown in FIGS. 15 and 16, the magnetic pole is magnetized in the opposite magnetic pole to the magnetic pole of the opposing first magnet 2b.

  At this time, as shown in FIG. 15, when the length of each region of the first magnetic body 5b opposed to the two magnetic poles of the first magnet 2b is equal, that is, the first magnetic body 5b corresponds to each of the first magnets 2b. When the length of the region facing the magnetic pole is equal, the center of the first magnetic body 5b is the boundary of the magnetized magnetic pole, and the balance of the magnetic force is maintained. That is, in this case, the force acting on the first magnetic body 5b is substantially only the magnetic attraction force F in the direction toward the first magnet 2b, and no force acting in the driving direction is generated.

  On the other hand, as shown in FIG. 16, when the first magnetic body 5b moves in the drive direction with respect to the first magnet 2b, the size of the area where the first magnetic body 5b is magnetized changes, and the balance of the magnetic force is reduced. Crumble. For example, when the first magnetic body 5b is displaced in the left direction in the figure with respect to the first magnet 2b as shown, the left region of the first magnetic body 5b facing the S pole on the left side of the first magnet 2b in the drawing The region is magnetized to the north pole, and the length of this region is longer than the length of the region magnetized to the right south pole. In this case, a force acts on the first magnetic body 5b to return in the direction of maintaining the balance of the magnetic force (that is, the right direction in the drawing). That is, this force is the restoring force R in the driving direction along the XY plane of the magnetic spring.

  From a different point of view, the restoring force R in the driving direction is a load when driving the movable portion 4. That is, if the restoring force R in the driving direction is made too strong, the power consumption of the VCM becomes large and the usage time of the battery becomes short. On the other hand, when a coil spring is used, the restoring force in the driving direction is proportional to the spring constant, so in order to reduce the restoring force and reduce the power consumption, it is necessary to lengthen the spring, and the installation space becomes large. I will.

  Further, as a matter of course, the magnetic attraction force F in the direction of attracting the first magnetic body 5b to the first magnet 2b also has an appropriate value, and if the magnetic attraction force F is too small, the driving of the movable portion 4 is not performed. If the magnetic attraction force F is too large, the balls 3a, 3b and 3c will wear out. Therefore, even in the case of using a magnetic spring as in the present embodiment, it is desirable to design the spring strength, that is, the magnetic attraction force F and the restoring force R to appropriate values.

  FIG. 17 is a graph showing the relationship between the amount of movement of the magnetic spring of the present embodiment along the driving direction of the first magnetic body 5b and the restoring force R along the driving direction. For comparison, the relationship between the shift amount along the XY plane of the coil spring that generates a tensile force having the same magnitude as the magnetic attraction force F of the magnetic spring and the restoring force along the plane direction is shown. According to this, it can be seen that the restoring force of the coil spring is 80 to 90% higher than that of the magnetic spring. That is, by using a magnetic spring, the restoring force can be made relatively small.

In this embodiment, in addition to the characteristic of such a magnetic spring, the magnetic attraction force F of the magnetic spring is controlled to a desired value separately from the restoring force R of the magnetic spring.
Basically, in order to apply the above-described restoring force R to the magnetic body 5b, the first magnetic body 5b needs to have a certain length along the driving direction. In that sense, when the elongated first magnetic body 5b is extended in the drive orthogonal direction along the polarization line D of the first magnet 2b, it is almost impossible to apply the restoring force in the drive direction to the first magnetic body 5b. Can not.

  As shown in FIG. 18, the lengths of the first magnet 2b along the arrangement direction of the S and N poles are LS and LN, and the moving amount of the movable portion 4 holding the first magnetic body 5b is the amount of movement of each magnetic pole. In the case where the length LS (LN) is not exceeded, the length L along the driving direction of the first magnetic body 5b may be longer than the length LS (LN) of each magnetic pole. In other words, when the movable portion 4 moves relative to the fixed frame 2, the lower limit value of the length of the first magnetic body 5 b causes at least a part of the first magnetic body 5 b to be the polarization line D of the first magnet 2 b. It will be good if it is the overlapping length. The polarization line D mentioned here is a fictitious straight line indicating the boundary between the south pole and the north pole.

  On the other hand, the magnetic attraction force F acting on the first magnetic body 5b is the projection area of the first magnetic body 5b with respect to the first magnet 2b, that is, the length L and width W of the first magnetic body 5b. It changes according to the thickness H (refer to FIG. 19) along the optical axis O direction and the distance between the first magnet 2b. In other words, the magnetic attraction force applied to the first magnetic body 5b by adjusting at least one parameter of the dimensions (L, W, H) of the first magnetic body 5b and the distance between the first magnetic body 2b It is possible to control F to a desired value.

  That is, according to the present embodiment, after setting the restoring force R of the magnetic spring to an appropriate value, the magnetic attraction force F of the magnetic spring can be set to a desired value regardless of the restoring force R, which is efficient Stable shake correction operation is possible.

  Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

  For example, in the embodiment described above, the case where the fixed frame 2 is provided with the magnets 2a, 2b, 2c and the movable frame 4 is provided with the magnetic bodies 5a, 5b, 5c has been described, as shown in FIG. The present invention can also be applied to a moving magnet type vibration isolation unit in which the movable frame 4 is provided with the magnets 2a, 2b and 2c. Also in this case, the dimensions of the magnetic members 5a, 5b and 5c fixed to the fixed frame 2 and the distance between the magnetic members 5a, 5b and 5c and the magnets 2a, 2b and 2c, etc. The magnetic attraction can be controlled to a desired value.

Hereinafter, the invention described in the claims at the beginning of the application of the present application is appended.
[1]
A first fixed part provided with a magnet,
A second fixed portion provided with a yoke that forms a magnetic circuit with the magnet;
A movable portion disposed between the first fixed portion and the second fixed portion and holding a coil facing the magnet and a driven member;
A plurality of rolling elements disposed between the movable portion and the first fixed portion and movably supporting the movable portion in a plane direction perpendicular to the alignment direction with respect to the first fixed portion;
A magnetic body provided on the movable portion so as to draw a magnetic spring between the magnet and the movable portion so as to attract the movable portion to the first fixed portion;
A drive unit having a.
[2]
The driving device according to [1], wherein the magnetic body is disposed to face the magnet in a positional relationship in which areas of two areas projected onto the magnetic poles of the magnet are equal.
[3]
[2] The driving device according to [2], wherein the magnetic body has a size in which the area projected onto the magnet is disposed inside the outer periphery of the magnet.
[4]
The driving device according to [3], wherein the magnetic body is formed in an elongated plate shape extended in a driving direction in which magnetic poles of the magnet are aligned.
[5]
The driving device according to [4], wherein a length of the magnetic body in the driving direction is longer than a length of each magnetic pole of the magnet in the driving direction.
[6]
Adjusting at least one of the projected area of the magnetic body relative to the magnet, the thickness of the magnetic body in the direction away from the magnet, and the distance between the magnetic body and the magnet; The driving device according to [1], which controls magnetic attraction between the magnet and the magnet.
[7]
The driving device according to [1], wherein the magnetic body is provided on the movable portion on the opposite side of the coil with the magnet.
[8]
The driving device according to [1], further including: a coil spring for attracting the movable portion to the first fixed portion separately from the magnetic spring.
[9]
A fixed part provided with a magnet,
A yoke forming a magnetic circuit between the magnet and the magnet;
A movable part disposed between the fixed part and the yoke and holding a coil facing the magnet;
A plurality of rolling elements disposed between the movable portion and the fixed portion and movably supporting the movable portion in a plane direction perpendicular to the alignment direction with respect to the fixed portion;
A magnetic body provided on the movable portion so as to draw a magnetic spring between the magnet and the movable portion so as to attract the movable portion to the fixed portion;
A drive unit having a.
[10]
A first fixed part,
A movable portion which holds an optical member to be subjected to blur correction and which is arranged in the optical axis direction of the optical member with respect to the first fixed portion;
A plurality of rolling elements disposed between the movable portion and the first fixed portion and movably supporting the movable portion in a plane direction orthogonal to the optical axis direction with respect to the first fixed portion;
A second fixed portion arranged in the optical axis direction on the opposite side of the movable portion to the first fixed portion;
A first magnet provided to the first fixed portion, a first coil provided to the movable portion to face the first magnet, and a first yoke provided to the second fixed portion to face the first magnet A first drive unit for moving the movable unit in a first direction orthogonal to the optical axis direction by energizing the first coil;
A second magnet provided to the first fixed portion, a second coil provided to the movable portion to face the second magnet, and a second yoke provided to the second fixed portion to face the second magnet A second drive unit for moving the movable unit in a second direction orthogonal to the optical axis direction and the first direction by energizing the second coil;
The first magnetic body includes the first magnetic body provided in the movable portion so as to face the first magnet, and the movable portion is attracted to the first fixed portion by a magnetic attraction force between the first magnet and the first magnetic body. A first magnetic spring,
The second magnetic body includes the second magnetic body provided in the movable portion so as to face the second magnet, and the movable portion is attracted to the first fixed portion by the magnetic attraction force between the second magnet and the second magnetic body. A second magnetic spring,
Blur correction device having.
[11]
The first magnetic body is disposed to face the first magnet in such a positional relationship that the areas of the two areas projected onto the magnetic poles of the first magnet are equal, and the second magnetic body is the first magnetic body The shake correction apparatus according to [10], which is disposed to face the second magnet in a positional relationship in which areas of two areas projected onto the respective magnetic poles of the two magnets are equal.
[12]
The first magnetic body has a size such that the area projected on the first magnet is disposed inside the outer peripheral portion of the first magnet, and the second magnetic body is an area projected on the second magnet The shake correction apparatus according to [11], having a size that is disposed inside the outer circumferential portion of the second magnet.
[13]
The first magnetic body is formed in an elongated plate shape extending in the first direction in which the magnetic poles of the first magnet are arranged, and the second magnetic body is formed by arranging the magnetic poles of the second magnet The blur correction device according to [12], which is formed in an elongated plate shape extended in the second direction.
[14]
The length along the first direction of the first magnetic body is longer than the length along the first direction of each magnetic pole of the first magnet, and the length along the second direction of the second magnetic body The blur correction device according to [13], wherein the length is longer than the length of each magnetic pole of the second magnet in the second direction.
[15]
At least one of a projected area of the first magnetic body with respect to the first magnet, a thickness of the first magnetic body in the optical axis direction, and a distance between the first magnetic body and the first magnet The magnetic attraction force between the first magnetic body and the first magnet is controlled to adjust the projection area of the second magnetic body to the second magnet, and the direction of the optical axis of the second magnetic body. Adjusting at least one of a thickness and a distance between the second magnetic body and the second magnet to control a magnetic attraction between the second magnetic body and the second magnet; [10] blur correction device.
[16]
The first magnetic body is provided on the movable portion on the opposite side across the first coil with the first magnet, and the second magnetic body is interposed between the second magnet and the second magnet. The blur correction device according to [10], which is provided on the movable portion on the opposite side across the second coil.
[17]
The shake correction apparatus according to [10], further including a coil spring for attracting the movable portion to the first fixed portion separately from the first magnetic spring and the second magnetic spring.
[18]
The shake correction apparatus according to [10], wherein the first yoke and the second yoke are integrated and double as the second fixing portion.

  DESCRIPTION OF SYMBOLS 1 ... image sensor, 2 ... fixed frame, 2a, 2b ... 1st magnet, 2c ... 2nd magnet, 3a, 3b, 3c ... ball, 4 ... movable frame, 4a, 4b ... 1st coil, 4c ... 2nd coil , 5a, 5b: first magnetic body, 5c: second magnetic body, 5d: magnetic body, 6: yoke, 7: coil spring, 10: anti-vibration unit, 100: camera, O: optical axis.

Claims (4)

A first fixed part provided with a magnet,
A second fixed portion provided with a yoke that forms a magnetic circuit with the magnet;
A movable portion disposed between the first fixed portion and the second fixed portion and holding a coil and an optical member facing the magnet;
A plurality of rolling elements disposed between the movable portion and the first fixed portion and movably supporting the movable portion in a plane direction perpendicular to the alignment direction with respect to the first fixed portion;
It is provided in the movable portion to face the magnet, and before the magnetic attraction force generated between the magnet and the movable portion is moved along the first direction in which the magnetic poles of the magnet are aligned. configure the magnetic spring to generate a restoring force for returning the position has a plate-shaped magnetic material Ru attracted to the first fixing portion above the movable portion,
The length in the first direction of the upper Symbol plate-shaped magnetic member is longer than the length of the first direction perpendicular to the second direction,
When the plate-like magnetic body is projected onto the magnet in a state where the end of the plate-like magnetic body in the first direction is positioned at the original position before the plate-like magnetic body moves. , Located inside the outer periphery of the magnet, and
The plate-shaped magnetic body, shake to the longer than the width of the coil in a first direction, for the upper Ki磁 pole characterized Oh Rukoto in a positional relationship in which the area is equal of the two regions the projection Correction device. Projected area with respect to the magnet of the upper Symbol plate-like magnetic bodies, by adjusting at least one of the distance between the magnet of the magnetic material in the direction away from the magnet thickness, and the magnetic body, The blur correction device according to claim 1, wherein a magnetic attraction force between the magnetic body and the magnet is controlled. Upper Symbol plate-shaped magnetic member is provided on the movable portion on the opposite side across the coil between the magnets, the shake correcting device according to claim 1.   The shake correction device according to claim 1, further comprising: a coil spring which attracts the movable portion to the first fixed portion separately from the magnetic spring.