Image stabilizer and lens barrel having the same

Abstract

To provide a shake correction device that has good detection accuracy and can be reduced in size.SOLUTION: A shake correction device has driving units that drive an optical system for correcting a shake in a direction including a component of a direction orthogonal to an optical axis; detection units that detect the position of the optical system; and a control unit that controls the driving units. The detection units are arranged at a first detection position and a second detection position on an optical axis orthogonal plane. At the first detection position, position information in a first detection direction and position information in a second detection direction different from the first detection direction are detected. At the second detection position, position information in a third detection direction is detected. At least two detection directions of the first to third detection directions are orthogonal to each other.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a shake correction device. [Background technology]

[0002] Conventionally, a shake correction device that corrects image shake has a mechanism for preventing the roll of the shake correction lens on a plane perpendicular to the optical axis in order to improve the correction effect. In recent years, in order to reduce the size of the lens barrel, there has been a demand for a shake correction device to have a large cutout in part so that a component arranged at a specific phase on the plane perpendicular to the optical axis inside the lens barrel can be arranged to overlap with a part of the shake correction device in the optical axis direction.

[0003] Patent Document 1 discloses a shake correction device that corrects the amount of roll by controlling two driving units according to the amount of roll around the optical axis detected by three detection means. The shake correction device of Patent Document 1 can eliminate the mechanism for preventing roll without reducing the correction effect, so it is possible to cut out a large part. In addition, the shake correction device of Patent Document 1 can be made smaller by arranging the detection means inside the coil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-276842 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the image stabilization device of Patent Document 1, the detection means is affected by the magnetic field of the coil, which deteriorates the detection accuracy. If the detection means is arranged outside the coil where it is not affected by the magnetic field of the coil, a space for the three detection means is required on the plane perpendicular to the optical axis in addition to the drive unit, so the amount of cutout of the image stabilization device becomes small, and as a result, the lens barrel becomes large.

[0006] An object of the present invention is to provide a shake correction device that has high detection accuracy and can be made compact. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a shake correction device including a drive unit that drives an optical system that corrects shake in a direction that includes a component in a direction perpendicular to an optical axis, a detection unit that detects position information of the optical system, and a control unit that controls the drive unit. To Orthogonal do on a plane In First detection position A first detection unit arranged and Different from the first detection position Second detection position Place Placed and a second detection unit. , The first detection unit includes a magnet and two magnetic detection units that detect the magnetism of the magnet, At the first detection position, position information in the first detection direction and position information in a second detection direction different from the first detection direction are detected, and at the second detection position, position information in a third detection direction is detected. The two are mutual They are characterized by being perpendicular to each other. Effect of the Invention

[0008] According to the present invention, it is possible to provide a shake correction device that has high detection accuracy and can be made compact. [Brief description of the drawings]

[0009] [Figure 1] 1 is an external view of a shake correction device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the image stabilizer as viewed from the subject side. [Diagram 3] FIG. 2 is an exploded perspective view of the image stabilizer as viewed from the image plane side. [Figure 4] FIG. [Diagram 5] 4 is a cross-sectional view at each detection position. [Figure 6] FIG. 4 is a diagram showing the arrangement of members in the lens barrel other than the shake correction device. [Figure 7]FIG. 2 is a diagram showing a control means of a lens barrel having a shake correction device. [Figure 8] 11 is an explanatory diagram of a method for acquiring the amount of movement of the shift barrel. FIG. [Figure 9] 9 is an explanatory diagram of a method for acquiring the amount of movement of the shift barrel when a detection direction different from that in FIG. 8 is included. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same reference numerals are given to the same members, and duplicated explanations will be omitted.

[0011] Fig. 1 is an external view of a shake correction device 100 according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of shake correction device 100 as viewed from the subject side, and Fig. 3 is an exploded perspective view of shake correction device 100 as viewed from the image plane side. The X direction (yaw direction) and Y direction (pitch direction) in Fig. 1 are directions perpendicular to the optical axis and are perpendicular to each other. In this embodiment, "perpendicular" includes not only cases where the directions are completely perpendicular, but also cases where the directions deviate from completely perpendicular within an allowable error range (cases where the directions can be considered to be perpendicular, or cases where the directions are approximately perpendicular).

[0012] The image stabilizer 100 is mounted on a lens barrel and has a function of correcting image blur. The cover member 400 is fixed to the shift base 200 by screws (not shown). The drive coils 510 and 511 used to drive the shift barrel 300 are fixed to the shift base 200. The drive coils 510 and 511 are connected to a flexible substrate (not shown) so as to be able to supply current. The shift barrel 300 holds a lens (optical system) 320 for image stabilizer. The shift barrel 300 is provided with drive magnets 520 and 521 used to drive the shift barrel 300. The shift barrel 300 is also provided with yokes 530 and 531. The drive magnets 520 and 521 are magnetically attracted to the yokes 530 and 531 so as to sandwich the shift barrel 300. The drive magnets 520 and 521 are also arranged to face the drive coils 510 and 511. The driving coil 510, the driving magnet 520, and the yoke 530 constitute a voice coil motor (first driving unit), which drives the shift barrel 300 in the yaw direction relative to the shift base 200. In addition, the driving coil 511, the driving magnet 521, and the yoke 531 constitute a voice coil motor (second driving unit), which drives the shift barrel 300 in the pitch direction relative to the shift base 200.

[0013] In this embodiment, the two driving units drive the shift barrel 300 in the yaw direction and the pitch direction, respectively, but this is not limited as long as the shift barrel 300 can be moved in a driving direction including a component in a direction perpendicular to the optical axis. For example, the two driving units may drive the shift barrel 300 in a driving direction different from the yaw direction and the pitch direction. In this case, it is preferable that the two driving units drive the shift barrel 300 in two directions that form 45 degrees with the yaw direction and the pitch direction, respectively. This allows the detection position for detecting the position information of the shift barrel 300 on the plane perpendicular to the optical axis to be on the X-axis or Y-axis, thereby reducing the processing load of the microcomputer 810 described later.

[0014] Also, a drive coil may be provided in the shift barrel 300, and a drive magnet and a yoke may be provided in at least one of the shift base 200 and the cover member 400.

[0015] Three balls 710, 711, and 712 are disposed between the shift base 200 and the shift barrel 300. The balls 710, 711, and 712 are in contact with the base-side ball contact portion 210 of the shift base 200 and the barrel-side ball contact portion 310 of the shift barrel 300, respectively. The balls 710, 711, and 712 are formed of a material such as ceramic or SUS304 so as not to be attracted to a driving magnet disposed nearby. The shift barrel 300 is biased against the shift base 200 by the tension spring 700, so that it can move in a direction including a component in a direction perpendicular to the optical axis. In this embodiment, the shift barrel 300 is biased against the shift base 200 by the tension spring 700, but may be biased against the shift base 200 by, for example, a magnetic bias.

[0016] 2 to 5, a detection unit that detects relative position information of the shift barrel 300 with respect to the shift base 200 will be described below. Fig. 4 is an explanatory diagram of the detection position of the detection unit. Fig. 5 is a cross-sectional view at a first detection position and a second detection position on a plane perpendicular to the optical axis.

[0017] In this embodiment, a first detection unit including Hall ICs (magnetic detection units) 610 and 612 and a magnet 620 is disposed at a first detection position indicated by point A in Fig. 4. A second detection unit including a Hall IC 611 and a magnet 621 is disposed at a second detection position indicated by point C in Fig. 4.

[0018] The Hall ICs 610 and 612 are fixed to the shift base 200. The Hall IC 611 is fixed to the cover member 400. The Hall ICs 610, 611, and 612 are each connected to a flexible substrate (not shown) and detect position information of the shift barrel 300 from a magnetic change caused by a position change of the shift barrel 300. The Hall ICs 610 and 611 are configured to detect different directions. Specifically, the Hall IC 610 detects position information of the shift barrel 300 in the pitch direction, and the Hall IC 611 detects position information of the shift barrel 300 in the pitch direction that is different from the detection direction detected by the Hall IC 610. The Hall IC 612 detects position information of the shift barrel 300 in the yaw direction. In this embodiment, since the Hall IC is used, the detection accuracy in a low-temperature or high-temperature environment can be improved and a long stroke can be detected compared to a Hall element. The magnets 620 and 621 are fixed to the shift barrel 300. The magnet 620 is disposed so as to face the Hall ICs 610 and 611. Moreover, the magnet 621 is disposed so as to face the Hall IC 612. The Hall ICs 610 and 611 are disposed so as to sandwich the magnet 620 in the optical axis direction, as shown in the enlarged view E of FIG. 5. By disposing the Hall ICs 610 and 611 in this manner, the number of parts can be reduced compared to the case where one magnet is used for one sensor. Furthermore, since one sensor can be eliminated, a large portion of the shake correction device 100 can be cut out (the shake correction device 100 can be made smaller in size).

[0019] In this embodiment, the Hall IC 610 detects position information of the shift barrel 300 in the pitch direction, and the Hall ICs 611 and 612 detect position information of the shift barrel 300 in the yaw direction, but the present invention is not limited to this. At least two of the three detection directions may be orthogonal to each other. For example, the Hall ICs 610 and 612 may detect position information of the shift barrel 300 in the yaw direction, and the Hall IC 611 may detect position information of the shift barrel in the pitch direction.

[0020] Note that while the position information of the shift barrel 300 is detected using a Hall IC in this embodiment, it may be detected using, for example, a sensor that optically detects position information.

[0021] Furthermore, although three sensors capable of detecting in one direction are used in this embodiment, for example, one sensor capable of detecting in two directions and one sensor capable of detecting in at least one direction may be used.

[0022] In addition, in this embodiment, the detection directions for position information of the shift barrel 300 are the yaw direction and the pitch direction, but they do not have to be the yaw direction and the pitch direction as long as they are orthogonal. The detection direction other than the two orthogonal directions may be a direction different from the two orthogonal directions.

[0023] In addition, it is preferable to set the first detection position and the second detection position so that the angle ABC on the drive unit side (the angle on the drive unit side among the angle formed by the straight line connecting the first detection position and the optical axis on the plane perpendicular to the optical axis and the straight line connecting the second detection position and the optical axis) is 240 degrees or less. In the lens barrel, the retaining cylinder that holds the movable group and the shake correction device 100 that move along the optical axis for focus, zoom, or aberration variation, etc., often moves along the optical axis by a cam mechanism consisting of cam followers and cam grooves. In this case, it is preferable to arrange the cam followers at three locations equally spaced by 120 degrees. In the area of ​​120 degrees or more between the two cam followers (the area on the opposite side to the drive unit), a member that is arranged at a specific phase, such as the drive unit 900 that drives the movable group, may be arranged as shown in FIG. 6. On the other hand, by setting the first detection position and the second detection position within the area of ​​240 degrees or less, it is possible to arrange the drive unit 900 so that it overlaps with a part of the shake correction device 100 in the optical axis direction.

[0024] FIG. 7 is a diagram showing a control means of a lens barrel having a shake correction device 100. The yaw angle detection sensor 820 and the pitch angle detection sensor 821 are sensors such as vibration gyros. The detection circuits 830, 831, and 832 include Hall ICs 610, 611, and 612, respectively. The microcomputer (control unit) 810 obtains a signal obtained by amplifying and appropriately compensating the difference signal between the shake signal from the yaw angle detection sensor 820 and the pitch angle detection sensor 821 and the signal from the detection circuits 830, 831, and 832. In addition, the microcomputer 810 uses the obtained signal to energize the drive coils 510 and 511 via the yaw coil drive circuit 840 and the pitch coil drive circuit 841, thereby driving the shift barrel 300. As a result, the shake correction lens 320 is controlled in position so that the above-mentioned difference signal becomes smaller, and is held at the target position.

[0025] Hereinafter, a method for acquiring the amount of movement of the shift barrel 300 will be described with reference to Fig. 8. Fig. 8 is an explanatory diagram of a method for acquiring the amount of movement of the shift barrel 300. Fig. 8(a) and Fig. 8(b) respectively show the states of the shift barrel 300 before and after movement.

[0026] The optical axis is (0,0), and a point that is x away from the optical axis in the yaw direction and y away from the optical axis in the pitch direction is (x,y). The positions (first detection positions) of the Hall ICs 610 and 611 are (xS1,yS1), and the position (second detection position) of the Hall IC 612 is (xS3,yS3). The amount of movement of the shift barrel 300 in the yaw direction is xL, the amount of movement in the pitch direction is yL, the amount of roll (amount of rotation on a plane perpendicular to the optical axis) is θ, and the detection values ​​of the Hall ICs 610, 611, and 612 are S1, S2, and S3, respectively.

[0027] At this time, the detection values ​​S1, S2, and S3 of the Hall ICs 610, 611, and 612 are the sum of the amount of movement due to the roll and the amount of translational movement of the shift barrel 300, respectively, and are expressed by the following equations (1) to (3).

[0028] S1=xS1·sinθ+yS1·cosθ-yS1+yL (1) S2=xS1 cosθ-yS1 sinθ-xS1+xL (2) S3=xS3 cosθ-yS3 sinθ-xS3+xL (3) The microcomputer 810 obtains the movement amount (xL, yL) of the shift barrel 300 expressed by the following expressions (4) and (5) from the expressions (1) and (2).

[0029] xL=S2+xS1·(1-cosθ)+yS1·sinθ (4) yL=S1-xS1·sinθ+yS1·(1-cosθ) (5) Further, from equations (2) and (3), the roll amount θ is expressed by either of the following equations (6a) and (6b) depending on the coordinates of the two detection positions.

[0030] θ=arcsin((S2-S3+xS1-xS3) / √((yS3-yS1) 2 +(xS1-xS3) 2 )) -arcsin((xS1-xS3) / √((yS3-yS1) 2 +(xS1-xS3) 2 )) (6a) θ=-arcsin((S2-S3+xS1-xS3) / √((yS3-yS1) 2 +(xS1-xS3) 2 )) +arcsin((xS1-xS3) / √((yS3-yS1) 2 +(xS1-xS3) 2 )) (6b) In order to reduce the processing load of the microcontroller 810, for example, the movement amount of the shift barrel 300 may be obtained using the following approximate formulas (7) and (8), or the relationship between the detection values ​​S1, S2, and S3 and the movement amount of the shift barrel 300 may be determined in advance and this value may be used.

[0031] xL=S2+(S3-S2)·yS1 / (yS1-yS3) (7) yL=S1-(S3-S2) xS1 / (yS1-yS3) (8) In addition, in this embodiment, the detection directions of the Hall ICs 610, 611, and 612 are the pitch direction, the yaw direction, and the yaw direction, respectively, but the present invention is not limited to this. For example, if the detection directions of the Hall ICs 610, 611, and 612 are the pitch direction, the yaw direction, and the pitch direction, respectively, the movement amount of the shift barrel 300 can be obtained by changing the formula (3) to the following formula (9).

[0032] S3=xS3·sinθ+yS3·cosθ-yS3+yL (9) Also, for example, as shown in FIG. 9, the detection directions of the Hall ICs 610, 611, and 612 are the pitch direction, the yaw direction, and the yaw direction and the angle θ S3 When the directions are such that the detected values ​​S1, S2, and S3 are expressed by the following equations (10) to (12), respectively.

[0033] S1=xS1·sinθ+yS1·cosθ-yS1+yL (10) S2=xS1 cosθ-yS1 sinθ-xS1+xL (11) S3=xS3·cosθ S3 ·cosθ-yS3·cosθ S3 sinθ -xS3 cosθ S3 +xL cosθ S3 +xS3 sinθ S3 sinθ+y S3 sinθ S3 cosθ -yS3 sinθ S3 +yL sinθ S3 (12) The microcomputer 810 obtains the movement amount (xL, yL) of the shift barrel 300 expressed by the following expressions (13) and (14).

[0034] xL=S2+xS1·(1-cosθ)+yS1·sinθ (13) yL=S1-xS1·sinθ+yS1·(1-cosθ) (14) Moreover, the roll amount θ is expressed by either of the following equations (15a) and (15b) depending on the coordinates of the two detection positions.

[0035] θ=arcsin((S3-S2·cosθ S3 -S1 sinθ S3 +(yS3-yS1)·sinθ S3 +(xS3-xS1)·cosθ S3 ) / √(((xS3-xS1)·sinθ S3 +(yS1-yS3)·cosθ S3 ) 2 +((yS3-yS1)·sinθ S3 +(xS3-xS1)·cosθ S3 ) 2 )) -arcsin(((yS3-yS1)·sinθ S3 +(xS3-xS1)·cosθ S3 ) / √(((xS3-xS1)·sinθ S3 +(yS1-yS3)·cosθ S3 ) 2 +((yS3-yS1)·sinθ S3 +(xS3-xS1)·cosθ S3 ) 2 )) (15a) θ=-arcsin((S3-S2·cosθ S3 -S1 sinθ S3 +(yS3-yS1)·sinθ S3 +(xS3-xS1)·cosθ S3 ) / √(((xS3-xS1)·sinθ S3 +(yS1-yS3)·cosθ S3 ) 2 +((yS3-yS1)·sinθ S3 +(xS3-xS1)·cosθ S3 ) 2 )) +arcsin(((yS3-yS1)·sinθS3 +(xS3-xS1)·cosθ S3 ) / √(((xS3-xS1)·sinθ S3 +(yS1-yS3)·cosθ S3 ) 2 +((yS3-yS1)·sinθ S3 +(xS3-xS1)·cosθ S3 ) 2 )) (15b) In order to reduce the processing load of the microcomputer 810, for example, the movement amount of the shift barrel 300 may be obtained using the following approximate formulas (16) and (17), or the relationship between the detection values ​​S1, S2, and S3 and the movement amount of the shift barrel 300 may be determined in advance and this value may be used.

[0036] xL=S2+(S3-S2·cosθ S3 -S1 sinθ S3 )·yS1 / ((xS3-xS1)·sinθ S3 +(yS1-yS3)·cosθ S3 ) (16) yL=S1-(S3-S2·cosθ S3 -S1 sinθ S3 )·xS1 / ((xS3-xS1)·sinθ S3 +(yS1-yS3)·cosθ S3 ) (17) The microcomputer 810 acquires the target position of the shake correction lens 320 according to the amount of movement xL in the yaw direction, the amount of movement yL in the pitch direction, the shake signal from the yaw angle detection sensor 820, and the shake signal from the pitch angle detection sensor 821. The microcomputer 810 also acquires the force required to move the shake correction lens 320 to the target position, and passes current through the drive coils 510 and 511 via the yaw coil drive circuit 840 and the pitch coil drive circuit 841 to generate the required force. This allows image blur to be corrected with high accuracy even if the shift barrel 300 rolls. Therefore, since the effect of the roll of the shift barrel 300 on the optical performance can be suppressed, there is no need to mount a mechanism for preventing roll on the lens barrel.

[0037] Note that a formula for obtaining the amount of roll may be used to perform control such as suppressing roll, or a mechanism for preventing roll may be provided in the lens barrel.

[0038] The above-described configuration makes it possible to provide a shake correction device 100 that has good detection accuracy and can be made compact. Furthermore, as described above, the drive unit 900 can be arranged so as to overlap a part of the shake correction device 100 in the optical axis direction in the space created by making the shake correction device 100 compact, making it possible to make the lens barrel compact.

[0039] In this embodiment, the drive unit (first actuator) 900 is disposed in the space formed by miniaturizing the image stabilizer 100, but the present invention is not limited to this. For example, members disposed at specific phases, such as a movable group, a guide bar (guiding member) for guiding the movable group in a straight line along the optical axis, and an actuator (second actuator) for driving the diaphragm, may be disposed.

[0040] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0041] 100 Image stabilizer 320 Image stabilizer lens (optical system) 510 Drive coil (drive unit) 511 Drive coil (drive unit) 520 Drive magnet (drive part) 521 Drive magnet (drive part) 530 Yoke (drive part) 531 Yoke (drive part) 610 Hall IC (detection part) 611 Hall IC (detection part) 612 Hall IC (detection part) 620 Magnet (detection part) 621 Magnet (detection part) 810 Microcomputer (control unit)

Claims

1. a drive unit that drives the optical system that corrects shake in a direction that includes a component perpendicular to the optical axis; A detection unit that detects position information of the optical system; A control unit that controls the drive unit, the detection unit includes a first detection unit arranged at a first detection position on a plane perpendicular to the optical axis, and a second detection unit arranged at a second detection position different from the first detection position, The first detection unit includes a magnet and two magnetic detection units that detect the magnetism of the magnet, At the first detection position, position information in a first detection direction and position information in a second detection direction different from the first detection direction are detected; At the second detection position, position information in a third detection direction is detected; 4. A shake correction device, wherein at least two of the first to third detection directions are orthogonal to each other.

2. The image stabilizer according to claim 1, wherein the control unit controls the drive unit using an amount of movement of the optical system on the plane obtained using a signal from the detection unit and an amount of rotation of the optical system on the plane based on the signal from the detection unit.

3. 3. The image stabilizer according to claim 1, wherein the first detection direction is perpendicular to the second detection direction.

4. 4. The image stabilizer according to claim 1, wherein the third detection direction is the same as the first detection direction or the second detection direction.

5. 5. The image stabilizer according to claim 1, wherein the detector comprises a magnetic detector and a magnet.

6. 6. The image stabilizer according to claim 1, wherein the two magnetic detection units are disposed so as to sandwich the magnet in the optical axis direction.

7. A shake correction device as described in any one of claims 1 to 6, characterized in that the angle on the driving unit side between a straight line connecting the first detection position on the plane to the optical axis and a straight line connecting the second detection position to the optical axis is 240 degrees or less.

8. The image stabilizer according to any one of claims 1 to 7, characterized in that the driving unit includes a first driving unit that drives the optical system in a first driving direction, and a second driving unit that drives the optical system in a second driving direction perpendicular to the first driving direction.

9. 9. The image stabilizer according to claim 8, wherein the first drive direction is the same as one of two orthogonal directions among the first to third detection directions.

10. 10. The image stabilizer according to claim 8, wherein the first drive direction is a direction that forms an angle of 45 degrees with each of two directions that are orthogonal to each other among the first to third detection directions.

11. A drive unit that drives an optical system that corrects shake in a direction that includes a component in a direction perpendicular to an optical axis; A detection unit that detects position information of the optical system; A control unit that controls the drive unit, the detection unit is disposed at a first detection position and a second detection position different from the first detection position on a plane perpendicular to an optical axis, At the first detection position, position information in a first detection direction and position information in a second detection direction different from the first detection direction are detected; At the second detection position, position information in a third detection direction is detected; At least two of the first to third detection directions are perpendicular to each other, the driving unit includes a first driving unit that drives the optical system in a first driving direction and a second driving unit that drives the optical system in a second driving direction perpendicular to the first driving direction, The image stabilizer according to claim 1, wherein the first drive direction is a direction that forms an angle of 45 degrees with each of two directions that are orthogonal to each other among the first to third detection directions.

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