Imaging apparatus

Abstract

To properly restrict translational movement and rotational movement of a movable portion in a driving device having the movable portion, which is translationally and rotationally movable within a plane with respect to a fixed portion.SOLUTION: A first blur correction unit 20 includes: a fixed portion 20a; a movable portion 20b that is arranged to be translationally movable and is rotational movable within a plane with respect to the fixed portion 20a; a plurality of actuators that drive the movable portion 20b; first restricting means that restricts translational movement of the movable portion 20b; and second restricting means that restricts rotational movement of the movable portion 20b. The second restricting means is provided at a location more remote from the center of rotation of the movable portion 20b with respect to the fixed portion 20a than the first restricting means.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a driving device and an imaging device including the driving device. [Background technology]

[0002] There are known driving devices that move a movable part in a plane relative to a fixed part, and one configuration that generates a driving force to drive the movable part is called a voice coil motor (VCM) system. In the VCM system, a magnet is placed on one of the movable and fixed parts and a coil is placed on the other, and the driving force is generated by passing electricity through the coil in the magnetic circuit formed by the magnets.

[0003] An example of an application of such a drive device is a shake correction mechanism mounted on an imaging device. In a shake correction mechanism, an imaging element or a shake correction lens is mounted on a movable part, and the movable part is driven to cancel out the detected shake based on the amount of shake detected by a predetermined sensor. In particular, a shake correction mechanism that mounts an imaging element on a movable part can be said to have higher shake correction performance than a shake correction mechanism that mounts a shake correction lens on a movable part, in that it can correct rotation around an axis (imaging optical axis) perpendicular to the imaging surface of the imaging element.

[0004] In such a drive device, a restricting portion is provided to prevent the movable portion from falling off the fixed portion. In a drive device capable of rotating around the imaging optical axis, such as a vibration reduction mechanism for an imaging device, such a restricting portion must be provided in a position that does not interfere with the rotation of the movable portion. Furthermore, in such a vibration reduction mechanism, a plurality of balls are typically disposed between the movable portion and the fixed portion in a rollable manner to reduce contact resistance and ensure smooth drive. In this case, a fence is provided to prevent the balls from flying out in a direction parallel to the rolling surface. Furthermore, the movable portion and the fixed portion are each provided with an abutting portion and an abutted portion to limit the movement of the movable portion relative to the fixed portion.

[0005] For example, Patent Document 1 discloses a technology for a vibration reduction device that moves a lens group using a two-axis drive device, in which a ball position is reset before shooting to prevent the ball from coming into contact with a fence during actual use. Patent Document 1 also describes that a movable mechanical end is provided to limit the movement of the moving part. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3969927 Summary of the Invention [Problem to be solved by the invention]

[0007] Users sometimes take pictures with an imaging device while walking, and the blur that occurs in this case is referred to here as “walking blur.” Because the amount of walking blur is greater than the amount of blur that occurs when a user takes pictures while standing still, there is a demand for a blur correction device that can offset a larger amount of blur.

[0008] A shake correction device for an imaging device can correct large amounts of shake by increasing the amount of movement of a movable part that holds an imaging element or a shake correction lens relative to a fixed part. Since shake caused by walking tends to cause large amounts of rotational shake around the imaging optical axis, the shake correction effect can be improved by increasing the amount of movement that the movable part can rotate around the imaging optical axis (with the imaging optical axis as the central axis) relative to the fixed part.

[0009] As mentioned above, the image stabilization device described in Patent Document 1 is only capable of translational movement within a plane perpendicular to the optical axis, and is not configured to allow rotational movement within the same plane. Furthermore, Patent Document 1 does not disclose a specific configuration for a movable mechanical end that limits the movement of the movable part. Furthermore, increasing the amount of rotational movement of the movable part relative to the fixed part increases the amount of outward protrusion of the movable part, which may result in an increase in the size of the imaging device. Therefore, in a drive device having a movable part that is capable of translational and rotational movement, a configuration is needed that appropriately restricts the translational and rotational movement of the movable part while suppressing outward protrusion of the movable part.

[0010] The present invention aims to provide a drive device having a movable part that can move translationally and rotationally within a plane relative to a fixed part, which can appropriately regulate the translational and rotational movements while preventing the movable part from protruding outward. [Means for solving the problem]

[0011] The drive device of the present invention is a drive device comprising a fixed part, a movable part that is arranged so as to be able to translate and rotate in a plane relative to the fixed part, and an actuator that drives the movable part, and is characterized in that it has a first regulating means that regulates the translational movement of the movable part and a second regulating means that regulates the rotational movement of the movable part, and the second regulating means is provided at a position farther from the center of rotation of the movable part relative to the fixed part than the first regulating means. [Effects of the Invention]

[0012] According to the present invention, in a drive device having a movable part capable of translational and rotational movement, a configuration is required that appropriately regulates the translational and rotational movement of the movable part while preventing the movable part from protruding outward. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing a schematic configuration of an imaging apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the first image stabilization unit. [Figure 3] FIG. 2 is an exploded perspective view of a movable part that constitutes the first image stabilization unit. [Figure 4] FIG. 1 is a diagram illustrating translational and rotational movements of an object on a plane. [Figure 5] 10 is a diagram showing the relationship between the distance from the center of rotation and the maximum movement amount and maximum rotation angle. FIG. [Figure 6] 10A and 10B are diagrams illustrating a configuration for restricting the relative position of a movable part with respect to a fixed part. [Figure 7] 10 is another diagram illustrating a configuration for restricting the relative position of the movable part with respect to the fixed part. FIG. [Figure 8] 10 is a schematic diagram showing the relationship between the ball and the enclosure when the movable part moves. FIG. [Figure 9] 10A and 10B are diagrams illustrating the relationship between the distance from the optical axis and the inner diameter of the enclosure. [Figure 10] FIG. 10 is a first diagram illustrating a first reset operation of the ball. [Figure 11] FIG. 10 is a second diagram illustrating the first reset operation of the ball. [Figure 12] FIG. 10 is a first diagram illustrating a second reset operation of the ball. [Figure 13] FIG. 10 is a second diagram illustrating the second reset operation of the ball. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Here, a configuration in which a driving device according to the present invention is applied to an image stabilization device for an imaging device will be described.

[0015] 1 is a diagram showing a schematic configuration of an image capturing device 10 according to an embodiment of the present invention. The image capturing device 10 is a so-called mirrorless digital camera, and includes an image capturing device main body 10a (hereinafter referred to as "main body 10a") and a lens barrel 10b that is detachable from the main body 10a.

[0016] Main body 10a includes imaging element 11 having imaging surface 11a, base member 13c, main body-side mount member 13a, camera control unit 14, first shake correction control unit 15a, first vibration detection unit 16a, image processing unit 17, and first shake correction unit 20. Lens barrel 10b includes imaging optical system 12 including shake correction lens 12b, lens-side mount member 13b, second shake correction control unit 15b, second vibration detection unit 16b, and second shake correction unit 60.

[0017] A virtual light ray that is representative of the light beam that is irradiated onto the imaging surface 11a of the imaging element 11 via the imaging optical system 12 is referred to as the "imaging optical axis 12a" (hereinafter referred to as the "optical axis 12a"), and a plane that is perpendicular to the optical axis 12a is referred to as the "optical axis perpendicular plane" (hereinafter referred to as the "optical axis perpendicular plane 12c"). The optical axis 12a passes through the center of the imaging surface 11a and is perpendicular to the imaging surface 11a.

[0018] In order to clarify the arrangement and positional relationship of the components constituting the imaging device 10 within the imaging device 10, the X, Y, and Z directions, which are orthogonal to one another, are defined as shown in Fig. 1. The Z direction is parallel to the optical axis 12a, the X direction is the width direction of the imaging device 10, and the Y direction is the height direction of the imaging device 10. When the X and Z directions are both within a horizontal plane, the Y direction becomes the vertical direction, and the plane 12c orthogonal to the optical axis becomes the XY plane.

[0019] The imaging element 11 is specifically a CMOS image sensor, a CCD image sensor, or the like, and is arranged with its imaging surface 11a facing the subject (the lens barrel 10b side) and perpendicular to the optical axis 12a. The imaging element 11 generates an image signal by photoelectrically converting an optical image of the subject formed on the imaging surface 11a by the imaging optical system 12. The image signal generated by the imaging element 11 is converted into image data through various processes in the image processing unit 17, and the generated image data is stored in a memory (storage device) not shown. The camera control unit 14 is a calculation unit within a main IC not shown, and controls the overall operation of the imaging device 10 by accepting input operations from the user via an operation unit not shown.

[0020] Imaging optical system 12 is composed of a lens group, an aperture, and the like (not shown) arranged inside lens barrel 10b, and forms an image of light reflected from a subject (not shown) on imaging surface 11a of imaging element 11. In imaging device 10, in order to position imaging element 11 with high positional accuracy relative to optical axis 12a, imaging element 11 is attached to base member 13c provided on main body 10a, and lens barrel 10b is also connected to base member 13c. In this case, imaging element 11 is attached to base member 13c via first image stabilizer unit 20. Lens barrel 10b is also connected to base member 13c via lens-side mount member 13b and main body-side mount member 13a.

[0021] The first image stabilization unit 20 corrects image blur caused by vibrations (vibrations or shaking) in the imaging device 10 by moving the imaging element 11 in any direction within the plane 12c orthogonal to the optical axis or by rotating it within the plane 12c orthogonal to the optical axis, thereby enabling a clear image of the subject to be obtained. Specifically, if the imaging device 100 changes its posture due to vibration during imaging, the imaging position of the subject light beam on the imaging surface 11a of the imaging element 11 changes, causing blur in the image obtained through the imaging element 11. In this case, if the posture change of the imaging device 10 is sufficiently small, the change in the imaging position is uniform within the imaging surface 11a and can be considered as a translational or rotational movement (image plane blur) within the plane 12c orthogonal to the optical axis. Therefore, by translating or rotating the imaging element 11 within the plane 12c orthogonal to the optical axis so as to cancel out this image plane blur, a clear image of the subject with image blur corrected can be obtained. It should be noted that the imaging element 11 may be configured to be movable in a direction perpendicular to the imaging surface when being moved in a direction parallel to the imaging surface.

[0022] Similarly, second blur correction unit 60 corrects image blur caused by vibrations occurring in imaging device 10 by moving blur correction lens 12b in a direction that can cancel out image plane blur within plane 12c orthogonal to the optical axis, thereby making it possible to obtain a clear subject image. Note that the principles of blur correction by moving imaging element 11 and blur correction lens 12b are well known, so a detailed explanation will be omitted. Furthermore, a configuration in which blur correction lens 12b moves in the optical axis direction when moving in the direction orthogonal to the optical axis may also be used.

[0023] The first image stabilization unit 20 generally has a fixed portion, a movable portion, and multiple drive force generation portions. The fixed portion is fixed to the base member 13c, and the movable portion holds the image sensor 11. The movable portion is supported by the fixed portion with three degrees of freedom, and is capable of translation in any direction within the plane 12c orthogonal to the optical axis relative to the fixed portion, and is also rotatable within the plane 12c orthogonal to the optical axis. In other words, the first image stabilization unit 20 is configured as a drive device (a so-called XYθ stage) capable of three-axis drive control, and is capable of moving the image sensor 11 in any direction within the plane 12c orthogonal to the optical axis, and of rotating within the plane 12c orthogonal to the optical axis.

[0024] Second blur correction unit 60 generally has a fixed portion, a movable portion, and multiple drive force generation portions. The fixed portion is fixed to a housing (not shown) of lens barrel 10b, and the movable portion holds blur correction lens 12b. The movable portion is supported by the fixed portion with two degrees of freedom and can move in any direction within plane 12c orthogonal to the optical axis relative to the fixed portion. In other words, second blur correction unit 60 is configured as a drive device (a so-called XY stage) capable of biaxial drive control, and can move blur correction lens 12b in any direction within plane 12c orthogonal to the optical axis.

[0025] First vibration detection unit 16a and second vibration detection unit 16b are shake detection means that detect angular velocity, acceleration, etc. in each direction of imaging device 10 as shake information of imaging device 10, and are specifically configured with a gyro sensor, acceleration sensor, etc. First shake correction control unit 15a and second shake correction control unit 15b integrate the angular velocity and acceleration detected by first vibration detection unit 16a and second vibration detection unit 16b, respectively, to calculate the amount of angular change and amount of movement of imaging device 10 in each direction as shake information.

[0026] Furthermore, first shake correction control unit 15a calculates a movement target value for image sensor 11 based on the shake information detected by first vibration detection unit 16a, and controls the movement of image sensor 11 by controlling the driving of first shake correction unit 20. Similarly, second shake correction control unit 15b calculates a movement target value for shake correction lens 12b based on the shake information detected by second vibration detection unit 16b, and controls the driving of second shake correction unit 60 to control the movement of shake correction lens 12b.

[0027] Note that imaging device 10 may be configured to include only first image blur correction unit 20. If second image blur correction unit 60 is not included, image blur correction lens 12b is basically unnecessary. Therefore, imaging optical system 12 of lens barrel 10b is designed to obtain the desired optical characteristics with a lens configuration that does not include image blur correction lens 12b.

[0028] Next, the detailed configuration of first shake correction unit 20, which embodies a drive device according to the present invention, will be described. Note that the configuration of first shake correction unit 20 is not applied to second shake correction unit 60. This is because, as will be apparent from the configuration of first shake correction unit 20 described below, if image sensor 11 included in first shake correction unit 20 were simply replaced with shake correction lens 12b, part of the light beam passing through shake correction lens 12b would be blocked. Therefore, for second shake correction unit 60, instead of the drive device according to the present invention, a drive device that does not drive and rotate movable part 20b, such as that applied to a lens barrel described in Patent Document 1 mentioned above, is used.

[0029] 2(a) and 2(b) are exploded perspective views of first image stabilization unit 20, with first image stabilization unit 20 viewed from different directions in Fig. 2(a) and Fig. 2(b). First image stabilization unit 20 includes fixed part 20a and movable part 20b. Note that in Fig. 2(a) and (b), movable part 20b is shown unexploded, and fixed part 20a is shown exploded.

[0030] The fixed portion 20a has a fixed member 21, a rear yoke 22, a first rear magnet group 23a, a second rear magnet group 23b, and a third rear magnet group 23c. The fixed member 21 is provided with a first opening 21a, a second opening 21b, and a third opening 21c. The first rear magnet group 23a, the second rear magnet group 23b, and the third rear magnet group 23c are each fixed to the rear yoke 22 with an adhesive or the like, and are arranged so as to be surrounded by the first opening 21a, the second opening 21b, and the third opening 21c.

[0031] In this embodiment, the first rear magnet group 23a, the second rear magnet group 23b, and the third rear magnet group 23c are each composed of two magnets magnetized in the optical axis direction (Z direction) and arranged to generate magnetic fields in opposite directions. However, this is not limiting, and a single magnet magnetized with two poles may also be used.

[0032] The fixed part 20a further includes a first pillar member 24a, a second pillar member 24b, a third pillar member 24c, a front yoke 25, a first front magnet 26a, a second front magnet 26b, and a third front magnet 26c. The front yoke 25 is fixed to the fixed member 21 with screws via the first pillar member 24a, the second pillar member 24b, and the third pillar member 24c. The first front magnet 26a, the second front magnet 26b, and the third front magnet 26c are each fixed to the front yoke 25 with an adhesive or the like.

[0033] In this embodiment, a single magnet magnetized with two poles is used as the first front magnet 26a, the second front magnet 26b, and the third front magnet 26c. However, this is not limiting, and two magnets magnetized in the optical axis direction and arranged so as to generate magnetic fields in opposite directions may also be used.

[0034] The first rear magnet group 23a and the first front magnet 26a, which are arranged side by side in the optical axis direction, form a first magnetic circuit. Similarly, the second rear magnet group 23b and the second front magnet 26b form a second magnetic circuit, and the third rear magnet group 23c and the third front magnet 26c form a third magnetic circuit.

[0035] The fixed portion 20a further includes a first restricting member 28, a second restricting member 29, and a cover 30. The rear yoke 22 includes a first restricting member 22a, and the front yoke 25 includes a second restricting member 25a (protrusion) that protrudes toward the movable portion 20b. The movement of the movable portion 20b is restricted within a predetermined range within the optical axis perpendicular plane 12c by the first restricting member 28, the second restricting member 29, the first restricting member 22a, the second restricting member 25a, the first pillar member 24a, the second pillar member 24b, and the third pillar member 24c (details will be described later). A cushioning material such as rubber is provided at the contact points of each of these components that restrict the movement of the movable portion 20b to absorb impacts upon contact, thereby preventing damage and reducing impact noise. The cover 30 prevents contact between the rear yoke 22 and a flexible printed circuit board, such as a driving FPC 35 (described later). A ball 36 is disposed between the movable portion 20b and the fixed member 21, as will be described in detail later.

[0036] 3(a) and 3(b) are exploded perspective views of the movable section 20b, with the movable section 20b viewed from different directions in FIGS. 3(a) and 3(b). The movable section 20b includes an image sensor holding member 31 and an image sensor 11. The image sensor 11 is fixed to the image sensor holding member 31 with an adhesive, details of which will be described later. The movable section 20b also includes a mask 32a, an infrared absorption filter 32b, an optical low-pass filter 32c, and a vibration unit 32f. The mask 32a, the infrared absorption filter 32b, and the optical low-pass filter 32c are held by a holder member 32d and a metal holder 32e and fixed to the image sensor 11 with an adhesive or the like. The mask 32a prevents unwanted light from entering the image sensor 11 from outside the imaging optical path. The optical low-pass filter 32c reduces moiré caused by the repeating pattern of the subject. The vibration unit 32f is provided on the optical low pass filter 32c and vibrates the optical low pass filter 32c to remove foreign matter such as dust adhering to the surface of the optical low pass filter 32c. Note that the principles and control of foreign matter removal by the vibration unit 32f are well known, and therefore a detailed description thereof will be omitted.

[0037] The movable part 20b includes a first coil 33a, a second coil 33b, a third coil 33c, and a driving FPC 35. The driving FPC 35 is disposed so as to overlap the first coil 33a, the second coil 33b, and the third coil 33c on the optical axis projection plane (on the XY plane when viewed from the Z direction), and is fixed to the imaging element holding member 31 with an adhesive or the like.

[0038] The imaging element holding member 31 has a first recess 31a, a second recess 31b, and a third recess 31c. The first coil 33a is disposed inside the first recess 31a, the second coil 33b is disposed inside the second recess 31b, and the third coil 33c is disposed inside the third recess 31c.

[0039] The first magnetic circuit and the first coil 33a form a VCM as a first actuator, the second magnetic circuit and the second coil 33b form a VCM as a second actuator, and the third magnetic circuit and the third coil 33c form a VCM as a third actuator.

[0040] A Lorentz force is generated in a direction perpendicular to the direction of the magnetic field generated in the first magnetic circuit in the optical axis direction and the direction of current flow in the first coil 33a. The resultant direction of the Lorentz force changes depending on the direction of current flow in the first coil 33a. Similar Lorentz forces are generated by the second magnetic circuit and the second coil 33b, and by the third magnetic circuit and the third coil 33c. The first and second actuators generate forces (driving forces) approximately parallel to the X direction. The sum of these forces generates a translational force in the X direction, and the difference between these forces generates a rotational force around the optical axis. The third actuator generates a translational force in the Y direction. Comparing the positions of the first restricting unit 22a and the first to third actuators, the first restricting unit 22a is located closer to the center of rotation of the movable unit 20b relative to the fixed member 21 than the first to third actuators. The actuator type is not limited to VCM; a vibration-type actuator or the like may also be used.

[0041] The drive FPC 35 is mounted with a first detector 35a, a second detector 35b, and a third detector 35c. The first detector 35a is disposed inside the first coil 33a, the second detector 35b is disposed inside the second coil 33b, and the third detector 35c is disposed inside the third coil 33c. The first detector 35a, the second detector 35b, and the third detector 35c are, for example, Hall elements. The first detector 35a detects the magnetic force of the first magnetic circuit, and based on the detection result, the first image stabilization control unit 15a calculates position information (specifically, the position and angle around the optical axis) of the movable part 20b relative to the fixed part 20a in the plane 12c perpendicular to the optical axis. The same applies to the second detector 35b and the third detector 35c.

[0042] The first coil 33a, the second coil 33b, and the third coil 33c are electrically connected to the driving FPC 35, and the first shake correction control unit 15a controls the magnitude of the current flowing through each coil via the driving FPC 35. In other words, the first shake correction control unit 15a controls the driving of the movable unit 20b using feedback control based on the deviation between the movement target value of the image sensor 11, which is based on the shake information detected by the first vibration detection unit 16a, and the current position of the image sensor 11, which is detected by the Hall element.

[0043] The movable part 20b is biased against the fixed member 21 constituting the fixed part 20a by an attractive force generated between the rear yoke 22 and the thrust magnet 39 due to the magnetic force of the thrust magnet 39, via balls 36 (see FIGS. 2(a) and 2(b)), which are rolling members. In other words, the rear yoke 22 and the thrust magnet 39 constitute a biasing part that biases the movable part 20b against the fixed part 20a. Note that in order to generate an attractive force between the rear yoke 22 and the thrust magnet 39, the rear yoke 22 needs to be a magnetic body (a member made of a magnetic material). Details of the biasing part will be described later.

[0044] The balls 36 are disposed inside the first, second, and third enclosures 31d, 31e, and 31f provided on the image sensor holding member 31, respectively. As will be described in detail later, the balls 36 roll when the movable part 20b moves relative to the fixed part 20a within the plane 12c orthogonal to the optical axis during image blur correction. Therefore, almost no load is generated due to friction between the balls 36 and the image sensor holding member 31 and the fixed part 21. Furthermore, movement of the movable part 20b in the direction opposite to the direction in which the biasing part formed by the rear yoke 22 and the thrust magnet 39 biases the movable part 20b is restricted by the front yoke 25 and the first restricting member 28. Therefore, even if an external force is applied that pulls the movable part 20b away from the fixed part 21 (moves the movable part 20b toward the lens barrel 10b) due to an impact or the like being applied to the image sensor 10, the movable part 20b will not fall off from the fixed part 20a.

[0045] The movable part 20b includes a connecting member 38, which bridges the opening 31i of the image sensor holding member 31 and is fixed to the image sensor holding member 31 with screws 45 on both sides (X-direction sides) of the optical axis 12a. The connecting member 38 is provided with two abutment portions 38a as protrusions that protrude toward the -Z side in the optical axis direction, and the two abutment portions 38a are inserted into two holes provided in the first restricting portion 22a of the rear yoke 22. As will be described in detail later, the translational movement of the movable part 20b within the optical axis-orthogonal plane 12c is restricted within a certain range by the outer circumferential surface of the abutment portion 38a abutting against the wall surface (inner wall) of the hole in the first restricting portion 22a. The position restricting means for the movable part 20b, which is formed by the abutment portions 38a and the first restricting portion 22a, will be referred to as the first restricting means as appropriate. It is sufficient that one of the hole serving as the first restricting portion 22a and the protrusion serving as the abutting portion 38a is provided on the fixed portion 20a and the other is provided on the movable portion 20b. In other words, a configuration may be adopted in which the protrusion is provided on the fixed portion 20a and the hole is provided on the movable portion 20b.

[0046] A thrust magnet 39 and a thrust yoke 40 are fixed to the connecting member 38 with adhesive or the like, and the thrust magnet 39 is magnetized in the optical axis direction. The thrust magnet 39 can be one that is magnetized with two poles so that magnetic fields of different directions are aligned in the Y direction, but it can also be one that is magnetized with a single pole.

[0047] The biasing portion formed by the rear yoke 22 and the thrust magnet 39 is disposed inside a triangle formed by the three balls 36 disposed inside the first enclosure 31d, the second enclosure 31e, and the third enclosure 31f, respectively. As a result, it is possible to generate a balanced biasing force on each ball 36.

[0048] Next, a configuration for regulating the relative position of the movable part 20b with respect to the fixed part 20a in the plane 12c orthogonal to the optical axis will be described in detail with reference to Figures 4 to 7. First, to help understand the operation of the movable part 20b, a general operation of a point at a predetermined position on the plane will be described with reference to Figures 4 and 5.

[0049] FIG. 4 is a diagram illustrating translational and rotational movement of an object on a plane with point O as the reference. In FIG. 4, position P1 is a position a predetermined distance away from point O, and position P2 is a position farther away from point O than position P1. Positions P1' and P2' are respectively positions obtained by rotating positions P1 and P2 counterclockwise by angle θ around point O. Furthermore, it is assumed that an object can move a distance d on the plane in any direction, regardless of its position on the plane. Range R1 indicates the range in which an object located at position P1 can move, and range R2 indicates the range in which an object located at position P2 can move. Similarly, range R1' indicates the range in which an object located at position P1' can move, and range R2' indicates the range in which an object located at position P2' can move.

[0050] An object can move by an angle θ on an arc centered at point O. That is, an object at position P1 (or position P1') can move between positions P1 and P1' on an arc centered at point O and passing through positions P1 and P1'. Similarly, an object at position P2 (or position P2') can move between positions P2 and P2' on an arc centered at point O and passing through positions P2 and P2'.

[0051] Therefore, the range in which an object at position P1 can move is range R1max, which is the locus obtained when range R1 is rotated by angle θ around point O. Similarly, the range in which an object at position P2 can move is range R2max, which is the locus obtained when range R2 is rotated by angle θ around point O. Note that range R1max can be said to be the range in which an object at position P1' can move, and similarly, range R2max can be said to be the range in which an object at position P2' can move.

[0052] In the ranges R1max and R2max, the maximum amount of translational movement possible is defined as d1max and d2max, respectively, and the maximum angle of rotation possible around point O is defined as θ1max and θ2max, respectively. Then, as can be seen from Figure 4, d1max<d2max、θ1max> θ2max. In this way, as the distance from point O, the center of rotation, increases, the maximum amount of movement dmax that can be made by translation alone increases, and the maximum angle of movement θmax that can be made by rotation alone around point O decreases. The relationship between the distance from point O (center of rotation) and dmax and θmax is shown in Figure 5.

[0053] Conversely, from Figure 5, it can be seen that if the translational movement and rotational movement of movable part 20b are to be restricted by the same restricting means, it is not easy to restrict rotational movement with high precision at a position close to optical axis 12a corresponding to point O. Furthermore, at a position far from optical axis 12a, the translational movement of movable part 20b would be restricted by an amount of movement that greatly exceeds the control range of translational movement. In view of these circumstances, in this embodiment, the movement range of movable part 20b is restricted using the configuration described below.

[0054] Next, a configuration for restricting movement of the movable part 20b relative to the fixed part 20a within the plane 12c orthogonal to the optical axis will be described with reference to FIGS. 6 and 7. FIG. 6(a) is a rear view (viewed from the rear side of the imaging device 100 along the optical axis 12a) illustrating a configuration for restricting the relative position of the movable part 20b relative to the fixed part 20a within the plane 12c orthogonal to the optical axis. Note that in FIG. 6(a), in order to clarify the configuration for restricting the position of the movable part 20b, the illustration of components involved in restricting the position of the movable part 20b is simplified, and components not directly involved in the position restriction are omitted. For example, the illustration is simplified by showing only the contact surfaces of the first restricting part 22a, first pillar member 24a, second pillar member 24b, and third pillar member 24c of the rear yoke 22, and the second restricting part 25a, first restricting member 28, and second restricting member 29 of the front yoke 25.

[0055] The imaging element 11 of the movable part 20b is substantially rectangular, with its long sides substantially parallel to the X direction and its short sides substantially parallel to the Y direction. The movable part 20b has a plurality of contact parts 201-208. The contact parts 201-208 are part of the outer circumferential surface of the imaging element holding member 31 that constitutes the movable part 20b. Some of the contact parts 201-208 are provided in recesses or notches formed in the movable part 20b (imaging element holding member 31) to reduce the amount of outward protrusion when the movable part 20b is rotated.

[0056] 7, when movable part 20b rotates, abutment portion 201 or abutment portion 202 abuts against first pillar member 24a, and abutment portion 206 or abutment portion 207 abuts against second restricting member 29, depending on the direction of rotation. Also, depending on the direction of rotation of movable part 20b, abutment portion 203 abuts against second restricting member 25a, abutment portion 204 abuts against second pillar member 24b, abutment portion 205 abuts against a protrusion of first restricting member 28, and abutment portion 208 abuts against third pillar member 24c. Abutment portions 201 to 208 and the corresponding pillar members, restricting portions, and position restricting means for movable part 20b, which are constituted by the restricting members, will be referred to as second restricting means as appropriate.

[0057] As described above, connecting member 38 connected to movable part 20b is provided with contact parts 38a at two locations, and the translational movement of movable part 20b is restricted by the outer peripheral surface of contact part 38a coming into contact with the inner wall of first restricting part 22a of rear yoke 22. Contact part 38a, contact parts 201-208, and the restricting parts corresponding thereto are arranged so as not to come into contact when first vibration reduction unit 20 is controlled by first vibration reduction control part 15a and moves movable part 20b within the range of movement required for vibration reduction.

[0058] First, a case will be described in which the movable part 20b translates within the plane 12c orthogonal to the optical axis without rotating around the optical axis 12a (rotation with the optical axis 12a as the central axis of rotation). In this case, the movement of the movable part 20b is restricted by two contact parts 38a provided on the connecting member 38 coming into contact with the first restricting part 22a of the rear yoke 22. At this time, the contact parts 201 to 208 that are farther from the optical axis 12a than the contact part 38a do not come into contact with their corresponding members. In other words, the translational movement of the movable part 20b is restricted only by the two contact parts 38a and the first restricting part 22a. FIG. 6(b) shows an example of a state in which the movable part 20b translates in the Y direction without rotating around the optical axis 12a.

[0059] Next, a case will be described in which the movable part 20b rotates clockwise within the plane 12c orthogonal to the optical axis when viewed from the rear side toward the front side of the imaging device 100. In this case, movement of the movable part 20b is restricted by contact between one or more of the abutment part 202 and the first pillar member 24a, the abutment part 203 and the second restricting part 25a, the abutment part 207 and the second restricting member 29, and the abutment part 208 and the third pillar member 24c. When the movable part 20b translates within the plane 12c orthogonal to the optical axis in addition to rotating clockwise, the abutment part 38a may abut against the first restricting part 22a. On the other hand, even when the rotation angle of the movable part 20b reaches its maximum in the clockwise direction from the state shown in FIG. 6(a), the abutment part 38a does not abut against the first restricting part 22a. Figure 7(a) shows the state in which the movable part 20b is stabilized by multiple regulating parts arranged to surround the optical axis 12a when the rotation angle of the movable part 20b reaches its maximum in the clockwise direction from the state in Figure 6(a).

[0060] Next, a case where the movable part 20b rotates counterclockwise within the plane 12c orthogonal to the optical axis when viewed from the rear side toward the front side of the imaging device 100 will be described. In this case, movement of the movable part 20b is restricted by contact between one or more of the abutment parts 201 and the first pillar member 24a, the abutment part 204 and the second pillar member 24b, the abutment part 205 and the first restricting member 28, and the abutment part 206 and the second restricting member 29. When the movable part 20b translates within the plane 12c orthogonal to the optical axis in addition to rotating counterclockwise, the abutment part 38a may abut against the first restricting part 22a. On the other hand, even when the rotation angle of the movable part 20b reaches its maximum in the counterclockwise direction from the state shown in FIG. 6(a), the abutment part 38a does not abut against the first restricting part 22a. 7(b) shows a state in which the movable part 20b is stabilized by the multiple restricting parts arranged to surround the optical axis 12a when the rotation angle of the movable part 20b reaches its maximum in the counterclockwise direction from the state shown in FIG. 6(a). With this configuration, it is possible to suppress the amount of protrusion of the movable part 20b outward from the fixed part 20a within the plane 12c perpendicular to the optical axis when the movable part 20b is rotated.

[0061] As described above, in this embodiment, among the movements of the movable part 20b within the plane 12c orthogonal to the optical axis, translational movement, which does not include rotation around the optical axis 12a, is restricted only by the contact between the contact part 38a, which is located at a small distance from the optical axis 12a, and the first restricting part 22a. Furthermore, among the movements of the movable part 20b within the plane 12c orthogonal to the optical axis, rotational movement around the optical axis 12a is restricted by the restricting elements corresponding to the contact parts 201 to 208 when the contact part 38a and the first restricting part 22a are not in contact with each other when the rotation angle is maximized. The restricting elements refer to the first pillar member 24a, the second restricting part 25a, the second pillar member 24b, the first restricting member 28, the second restricting member 29, and the third pillar member 24c.

[0062] As described above, elastic members such as rubber are provided at the pillar members, restricting portions, and restricting members at their portions that come into contact with movable portion 20b to absorb impacts and suppress the generation of impact noise. In first image stabilization unit 20, the rotational movement of movable portion 20b is restricted by movable portion 20b coming into contact with at least three pillar members, restricting portions, or restricting members at approximately the same time. This distributes the force acting on the pillar members, restricting portions, or restricting members, and suppresses deterioration of the elastic members.

[0063] When performing shake correction control using first shake correction unit 20 during actual image capture, it is necessary to perform an operation to adjust the position of ball 36 in advance (hereinafter referred to as a "reset operation") so that ball 36 does not roll and the drive load does not increase. The reset operation may be performed, for example, immediately after imaging device 10 is powered on. Alternatively, the reset operation may be performed by a user operation. Next, the reset operation of first shake correction unit 20 will be described in detail with reference to FIGS. 8 to 13.

[0064] First, the first enclosure 31d, the second enclosure 31e, and the third enclosure 31f will be described. Note that the first enclosure 31d, the second enclosure 31e, and the third enclosure 31f will be described in the same manner, and therefore, the first enclosure 31d, the second enclosure 31e, and the third enclosure 31f will be collectively referred to as the "enclosure 311."

[0065] FIG. 8(a) is a schematic diagram illustrating the relationship between the ball 36 and the enclosure 311 in the plane 12c orthogonal to the optical axis when the movable part 20b moves relative to the fixed part 20a in the plane 12c orthogonal to the optical axis (hereinafter simply referred to as "the movable part 20b moves"). The enclosure 311 is circular and is provided on the imaging element holding member 31. It prevents the ball 36, which is sandwiched between the fixed part 21 and the imaging element holding member 31, from falling out in all directions in the plane 12c orthogonal to the optical axis. In FIG. 8(a), the positions of the movable part 20b and the ball 36 before movement are indicated by dashed lines. When the movable part 20b moves a distance S to the right in FIG. 8(a), the ball 36 rolls due to friction between the fixed part 21 and the imaging element holding member 31. At this time, the ball 36 rolls in the same direction as the movement of the movable part 20b, a distance S / 2, which is half the movement distance of the movable part 20b. In FIG. 8(a), the positions of the movable part 20b and the ball 36 after movement are shown by solid lines.

[0066] FIG. 8(b) is a schematic diagram illustrating the relationship between the enclosure 311 and the ball 36 in a plane perpendicular to the optical axis 12c when the ball 36 comes into contact with the enclosure 311 as the movable part 20b moves. In FIG. 8(b), the positions of the movable part 20b and the ball 36 before movement are indicated by dashed lines. Assume that the movable part 20b moves a distance S to the right in FIG. 8(b). If the distance between the left side of the enclosure 311 and the left side of the ball 36 before the movable part 20b moves is less than S / 2, the ball 36 comes into contact with the left side of the enclosure 311 during the movement of the movable part 20b. As a result, the ball 36 cannot roll and moves while being dragged by the enclosure 311 while in contact with the enclosure 311. In this state, greater friction occurs than when the ball 36 is rolling. However, if the movable part 20b returns to its original position (dashed line position) from this state and then performs the same operation (moving to the solid line position), the ball 36 will not come into contact with the enclosure part 311 during the second or subsequent operation, because the ball 36 was dragged by the enclosure part 311 during the first operation.

[0067] Here, the inner diameter of enclosure 311 will be described. When first blur correction control unit 15a controls first blur correction unit 20 to perform blur correction, the movement of movable part 20b is limited within a range of a predetermined translational movement amount and within a range of a predetermined rotation angle about optical axis 12a. By rolling ball 36 within this range so that ball 36 does not come into contact with (the wall surface of) enclosure 311, the frictional load can be reduced.

[0068] Fig. 9(a) is a diagram illustrating the relationship between the distance from the optical axis 12a and the inner diameter of the enclosure 311. Let a be the translational movement amount of the movable part 20b, φ be the rotation angle of the movable part 20b about the optical axis 12a, and b be the diameter of the ball 36. Then, as shown in Fig. 9, the inner diameter of the enclosure 311 at a position a distance c away from the optical axis 12a is expressed as a + b + c × sinφ + z. Note that 'z' is a mechanical allowance and is a value greater than or equal to 0 (zero).

[0069] Figure 9(b) is a diagram showing the first region 312 in which the ball 36 should be located so that it will not come into contact with the enclosure 311 even when the movable part 20b translates by a distance a and rotates by an angle φ around the optical axis 12a during shake correction.

[0070] 8(a), when movable part 20b translates by distance a, ball 36 rolls by a distance a / 2 in the same direction. If the diameter (inner diameter) of enclosure 311 is 'D', and ball 36 is located in second region 313, which is concentric with enclosure 311 and surrounded by a circle of diameter Da before movable part 20b moves, ball 36 will not come into contact with enclosure 311 even if movable part 20b translates by distance a.

[0071] Similarly, when movable part 20b rotates by angle φ around optical axis 12a, ball 36 rolls by angle φ / 2 in the same direction. Therefore, the common area between third region 313a, which is formed after second region 313 rotates by angle +φ / 2 around optical axis 12a, and fourth region 313b, which is formed after second region 313 rotates by angle −φ / 2, becomes first region 312. If ball 36 is located within first region 312, ball 36 will not protrude from second region 313 even if movable part 20b rotates by angle φ around optical axis 12a. In other words, if ball 36 is located within first region 312, ball 36 will not come into contact with enclosure 311 even if movable part 20b translates by distance a and rotates by angle φ around optical axis 12a.

[0072] Next, a first example of the reset operation (hereinafter referred to as the "first reset operation") will be described with reference to Figures 10 and 11. Figures 10(a) to (c) and Figures 11(a) and (b) are diagrams schematically showing areas where the ball 36 may be located relative to the enclosure 311 when the movable part 20b moves in the first reset operation.

[0073] 10(a) is a diagram showing fifth region 314 in which ball 36 exists after movable section 20b is moved translationally without rotational movement so as to describe a circle of radius e around optical axis 12a. As described above, ball 36 moves to a position where it will not come into contact with enclosure section 311 within the range it has passed through once, and therefore after the movement it exists within fifth region 314. The diameter of fifth region 314 is smaller than the inner diameter D of enclosure section 311 by half the diameter of the circle through which it moves, that is, by 'e', ​​and is therefore 'D-e'.

[0074] When movable section 20b rotates counterclockwise around optical axis 12a by angle α (first rotation direction rotatable around optical axis 12a) from the state shown in Fig. 10(a), ball 36 falls within sixth region 314a shown in Fig. 10(b). This is because when fifth region 314 rotates around optical axis 12a by angle α / 2 and ball 36 abuts against enclosure 311 at that time, ball 36 is dragged by enclosure 311 without rolling.

[0075] When the movable part 20b rotates by an angle -α about the optical axis 12a from the state shown in FIG. 10(b) (in other words, when it rotates by an angle α in a second rotation direction that is the opposite direction to the first rotation direction), the ball 36 falls within the seventh region 314b shown in FIG. 10(c). Similarly, when the movable part 20b rotates by an angle -α about the optical axis 12a from the state shown in FIG. 10(c), the ball 36 falls within the eighth region 314c shown in FIG. 11(a). This is because the seventh region 314b rotates by an angle -α / 2 about the optical axis 12a, and if the ball 36 comes into contact with the enclosure 311 at that time, the ball 36 is dragged without rolling. When the movable part 20b rotates by an angle α about the optical axis 12a from the state shown in FIG. 11(a), the ball 36 falls within the ninth region 314d shown in FIG. 11(b).

[0076] Therefore, if ninth region 314d is included in first region 312, even if movable part 20b translates by distance a and rotates by angle φ around optical axis 12a during shake correction, ball 36 will not come into contact with enclosure 311. In other words, the first reset operation is the translational and rotational movement of movable part 20b from FIG. 10(a) to FIG. 11(b) as described above. Because translational movement is performed in the first reset operation, the movement angle in the rotational movement can be made small, and during actual shake correction, contact of ball 36 with enclosure 311 can be avoided within the drive control range of movable part 20b, maintaining a small drive load.

[0077] Next, a second example of the reset operation (hereinafter referred to as the "second reset operation") will be described with reference to Figures 12 and 13. Figures 12(a) to (c) and Figures 13(a) and (b) are diagrams schematically showing areas where the ball 36 may be located relative to the enclosure 311 when the movable part 20b moves in the second reset operation.

[0078] Fig. 12(a) is a diagram showing a state in which ball 36 is present inside enclosure 311. When movable section 20b rotates counterclockwise around optical axis 12a by angle β from the state shown in Fig. 12(a), ball 36 falls within tenth region 314e shown in Fig. 12(b). This is because the region in which ball 36 falls in Fig. 12(a) rotates around optical axis 12a by angle β / 2, and if ball 36 comes into contact with enclosure 311 at that time, ball 36 is dragged by enclosure 311 without rolling.

[0079] When the movable part 20b rotates around the optical axis 12a by an angle -β (clockwise by an angle β) from the state shown in FIG. 12(b), the ball 36 falls within the eleventh region 314f shown in FIG. 12(c). Similarly, when the movable part 20b rotates around the optical axis 12a by an angle -β from the state shown in FIG. 12(c), the ball 36 falls within the twelfth region 314g shown in FIG. 13(a). This is because when the eleventh region 314f rotates around the optical axis 12a by an angle -β / 2 and the ball 36 abuts against the enclosure 311, the ball 36 is dragged by the enclosure 311 without rolling. When the movable part 20b rotates around the optical axis 12a by an angle β from the state shown in FIG. 13(a), the ball 36 falls within the thirteenth region 314h shown in FIG. 13(b).

[0080] Therefore, if the thirteenth region 314h is included in the first region 312, the ball 36 will not come into contact with the enclosure 311 even if the movable part 20b translates a distance a and rotates an angle φ around the optical axis 12a during shake correction. In other words, the second reset operation is equivalent to the rotational movement of the movable part 20b from FIG. 12(a) to FIG. 13(b) as described above. However, the angle β must be set to an angle greater than the maximum rotation angle that can be controlled during shake correction. The second reset operation does not require translational movement of the movable part 20b, and during actual shake correction, the ball 36 can be prevented from coming into contact with the enclosure 311 within the drive control range of the movable part 20b, thereby maintaining a small drive load.

[0081] The first reset operation and the second reset operation are performed within a range where the movable part 20b does not come into contact with the fixed part 20a in the first regulating means and the second regulating means, because a collision sound would be generated if the movable part 20b and the fixed part 20a came into contact with each other.

[0082] While the present invention has been described in detail above based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the gist of the present invention are also included in the present invention. Furthermore, each of the above-described embodiments merely represents one embodiment of the present invention, and each embodiment can be combined as appropriate.

[0083] For example, in the above embodiment, an example was described in which the drive device according to the present invention is applied to an image stabilization device for an imaging device. However, the application of the drive device according to the present invention is not limited to this. For example, the drive device according to the present invention can be applied to an XYθ table on which a sample to be observed in a microscope is placed, or an XYθ table on which an assembly target object is placed in various manufacturing devices. Furthermore, in the above embodiment, a so-called mirrorless camera is used as the imaging device 10, but the drive device according to the present invention can also be applied to an image stabilization device for a digital single-lens reflex camera equipped with a quick-return mirror mechanism. [Explanation of symbols]

[0084] 10. Imaging device 11 Image sensor 15a First image stabilization control section 20 First image stabilization unit 20a Fixed part 20b Moving part 22a First Regulatory Section 36 balls 38a Contact part 28 First restricting member 29 Second restricting member 24a First pillar member 24b Second pillar member 24c Third pillar member 25a Second Regulatory Section 201~208 Contact part 311 Enclosure

Claims

1. A fixed portion; a movable part arranged to be translatable and rotatable in a plane relative to the fixed part; an actuator that drives the movable part; A drive device comprising: a first restricting means for restricting translational movement of the movable part; a second restricting means for restricting the rotational movement of the movable part; The drive device according to claim 1, wherein the second restricting means is provided at a position farther from the center of rotation of the movable part relative to the fixed part than the first restricting means.

2. 2. The drive device according to claim 1, wherein when the translational movement of the movable part relative to the fixed part is restricted by the first restricting means, the second restricting means does not restrict the rotational movement of the movable part.

3. 3. The drive device according to claim 1, wherein when the rotational movement of the movable part relative to the fixed part is restricted by the second restricting means, the first restricting means does not restrict the translational movement of the movable part.

4. the first restricting means is configured by a hole provided in one of the fixed part and the movable part and a protrusion provided in the other part and inserted into the hole, The drive device according to any one of claims 1 to 3, characterized in that the translational movement of the movable part relative to the fixed part is regulated by the outer surface of the protrusion abutting against the inner wall of the hole when the movable part moves translationally.

5. the second restricting means is configured by a pillar portion or a protrusion portion provided on the fixed portion and a part of the outer periphery of the movable portion, The drive device according to any one of claims 1 to 4, characterized in that the rotational movement of the movable part relative to the fixed part is regulated by the part of the movable part abutting against the pillar part or the protrusion part when the movable part rotates.

6. 6. The drive device according to claim 5, wherein at least three of the pillars or protrusions come into contact with the part of the movable part substantially simultaneously.

7. 7. The drive device according to claim 1, wherein the first restricting means is provided at a position closer to the center of rotation of the movable part relative to the fixed part than the actuator.

8. a plurality of rolling members disposed between the fixed portion and the movable portion; the movable portion has a surrounding portion provided for each of the plurality of rolling members to prevent the rolling members from falling off from the driving device, A drive device as described in any one of claims 1 to 7, characterized in that it has a control means for performing a reset operation in which the movable part is driven in advance to position the plurality of rolling members in a predetermined area so that the rolling members do not contact the inner wall of the enclosure within the drive control range when actually driving the drive device.

9. 9. The drive device according to claim 8, further comprising a biasing portion that biases the movable portion against the fixed portion via the rolling member.

10. The reset operation is a first operation of moving the movable part in translation so as to draw a circle of a predetermined radius from the rotation center without rotating the movable part; a second operation of rotating the movable part around the rotation center by a predetermined rotation angle, 10. The drive device according to claim 8, wherein the control means performs the second operation after performing the first operation.

11. The drive device according to claim 10, characterized in that the second operation rotates the movable part by the same angle in a first rotation direction about the rotation center and in a second rotation direction that is opposite to the first rotation direction.

12. 10. The drive device according to claim 9, wherein the reset operation rotates the movable part around the rotation center at a rotation angle greater than an angle at which the rotational movement of the movable part is controlled.

13. The drive device according to claim 12, wherein the reset operation rotates the movable part by the same angle in a first rotation direction about the rotation center and in a second rotation direction opposite to the first rotation direction.

14. A drive device according to any one of claims 1 to 13; an imaging device held by the movable part of the driving device, the imaging element is held by the movable section such that an imaging surface of the imaging element is translatable and rotatable within a plane perpendicular to an imaging optical axis of the imaging device; a detection means for detecting an image blur of the imaging device; and a blur correction unit that controls the driving of the movable part so as to cancel out the image blur.

15. a movable part that is translatable and rotatable in a plane relative to a fixed part; a plurality of rolling members disposed between the fixed portion and the movable portion, A control method for preventing the rolling members from contacting an inner wall of the enclosure within a drive control range when actually driving a drive device in which each of the plurality of rolling members is disposed inside an enclosure provided on the movable part, the method comprising: a first step of translating the movable part so as to draw a circle of a predetermined radius from a rotation center of the movable part without rotating the movable part; a second step of rotating the movable part around the rotation center by a predetermined rotation angle after the first step is performed, A control method for a drive device, characterized in that in the second step, the movable part is rotated by the same angle in a first rotation direction around the rotation center of the movable part and in a second rotation direction that is opposite to the first rotation direction.

16. a movable part that is translatable and rotatable in a plane relative to a fixed part; a plurality of rolling members disposed between the fixed portion and the movable portion, A control method for preventing the rolling members from contacting an inner wall of the enclosure within a drive control range when actually driving a drive device in which each of the plurality of rolling members is disposed inside an enclosure provided on the movable part, the method comprising: a step of rotating the movable part at a rotation angle greater than an angle at which the rotation movement of the movable part is controlled, A control method for a drive device, characterized in that in the step, the movable part is rotated by the same angle in a first rotation direction around the rotation center of the movable part and in a second rotation direction that is opposite to the first rotation direction.

Images