Imaging apparatus

Abstract

To provide an imaging apparatus capable of reducing power consumption regardless of a posture, with a simple configuration.SOLUTION: An imaging apparatus (10a) includes: a fixed member (21); a movable member (31) capable of moving while holding an imaging element (11); a first yoke member (27) arranged in the fixed member; a second yoke member (37) arranged in the movable member; and a magnet member (38) arranged in one of the first yoke member and the second yoke member. The first surface (27a) of the first yoke member and the second surface (37a) of the second yoke member overlap with each other in a first direction perpendicular to an optical axis direction. The third surface of the first yoke member and the fourth surface of the second yoke member overlap with each other in a second direction parallel to an optical axis. The magnet member, the first yoke member, and the second yoke member constitute a magnetic circuit passing through the first surface, the second surface, the third surface, and the fourth surface.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to an imaging device.

Background Art

[0002] Conventionally, an imaging device including a shake correction mechanism driven by a voice coil motor (VCM) has been known. Such a shake correction mechanism can reduce image blur by moving a movable part that holds an image sensor in a plane with respect to a fixed part. An imaging device having a shake correction mechanism that moves an image sensor using a VCM needs to constantly generate a driving force by energizing a coil to hold the movable part in order to properly maintain the position of the image sensor. Therefore, power consumption increases, and the number of shots that can be taken may decrease.

[0003] Patent Document 1 discloses an imaging device including a gravity support part that supports a movable part with a force having the same magnitude as the gravity applied to the movable part. Patent Document 2 discloses an imaging device that assists in holding a movable part by utilizing a reaction force caused by bending a flexible substrate that electrically connects an image sensor and a control board.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the imaging device disclosed in Patent Document 1, a gravity support part for supporting a movable part is required, so the imaging device becomes complicated and large-sized. In the configuration disclosed in Patent Document 2, power consumption cannot be reduced depending on the posture of the imaging device.

[0006] Therefore, an object of the present invention is to provide an imaging device that can reduce power consumption regardless of the posture with a simple configuration.

Means for Solving the Problems

[0007] An imaging device according to an aspect of the present invention includes a fixed member, a movable member that holds an imaging element and is movable in a direction orthogonal to the optical axis with respect to the fixed member, a driving unit that drives the movable member, a rolling member disposed between the fixed member and the movable member, a first yoke member disposed on the fixed member, a second yoke member disposed on the movable member, and a magnet member disposed on one of the first yoke member and the second yoke member. A first surface of the first yoke member and a second surface of the second yoke member overlap each other in a first direction perpendicular to the optical axis direction, and a third surface of the first yoke member and a fourth surface of the second yoke member overlap each other in a second direction parallel to the optical axis. The magnet member, the first yoke member, and the second yoke member constitute a magnetic circuit passing through the first surface, the second surface, the third surface, and the fourth surface.

[0008] Other objects and features of the present invention will be described in the following embodiments.

Effects of the Invention

[0009] According to the present invention, it is possible to provide an imaging device that can reduce power consumption regardless of the posture with a simple configuration.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, a configuration in which the drive device according to the present invention is applied to an image blur correction device of an imaging device will be described as an example, but the application examples of the drive device according to the present invention are not limited to imaging devices.

[0012] First, referring to FIG. 1, the imaging system 10 according to this embodiment will be described. FIG. 1 is a schematic configuration diagram of the imaging system 10. The imaging system 10 is a so-called mirrorless digital camera, and includes a main body part 10a as an imaging device (camera body) and a lens device (interchangeable lens) 10b that is detachable from the main body part 10a. However, this embodiment is not limited to this, and is also applicable to an imaging device in which the main body part and the lens device are integrally configured.

[0013] The main body part 10a includes an imaging device 11 having an imaging surface 11a, a base member 13c, a mounting member (main body part mounting member) 13a, a camera control unit 14, a first shake correction control unit 15a, a first vibration detection unit 16a, an image processing unit 17, and a first shake correction unit 50. The first shake correction control unit 15a is control means for controlling a drive unit that drives the holding member 31. The lens device 10b includes an imaging optical system 12 including a shake correction lens 12b, a mounting member (lens side mounting member) 13b, a second shake correction control unit 15b, a second vibration detection unit 16b, and a second shake correction unit 60.

[0014] A virtual ray representative of the light beam irradiated onto the imaging surface 11a of the imaging device 11 through the imaging optical system 12 is referred to as an optical axis (imaging optical axis) 12a, and a plane orthogonal to the optical axis 12a is referred to as an optical axis orthogonal plane 12c. The optical axis 12a passes through the center of the imaging surface 11a and is orthogonal to the imaging surface 11a. Also, in order to clarify the arrangement and positional relationship within the imaging system 10 of each part constituting the imaging system 10, X, Y, and Z directions orthogonal to each other are defined. The Z direction is a direction parallel to the optical axis 12a, the X direction is the width direction (horizontal direction) of the imaging system 10, and the Y direction is the height direction (vertical direction) of the imaging system 10. When both the X direction and the Z direction are in the horizontal plane, the Y direction becomes the vertical direction. Thus, the optical axis orthogonal plane 12c becomes the XY plane. Also, the posture (camera posture) of the imaging system 10 when the Z direction coincides with the direction of the optical axis 12a is referred to as the "correct position".

[0015] The imaging device 11 is a photoelectric conversion device such as a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. The imaging device 11 is arranged with its imaging surface 11a facing the subject side (the lens device 10b side) so that the imaging surface 11a is orthogonal to the optical axis 12a. The imaging device 11 generates an image signal by photoelectrically converting the optical image of the subject formed on the imaging surface 11a by the imaging optical system 12. The image signal generated by the imaging device 11 is converted into image data by performing various processes in the image processing unit 17 and stored in a memory (storage device) not shown. The camera control unit 14 is an arithmetic means in a main IC not shown, receives an input operation from a user via an operation means not shown, and controls the overall operation of the imaging system 10.

[0016] The imaging optical system 12 includes a lens group (not shown) arranged inside the lens device 10b, and forms a reflected light from a subject (not shown) on the imaging surface 11a of the imaging device 11. In the imaging system 10, in order to arrange the imaging device 11 with high positional accuracy with respect to the optical axis 12a, the imaging device 11 is attached to a base member 13c provided on the main body 10a, and the lens device 10b is also connected to the base member 13c. At this time, the imaging device 11 is attached to the base member 13c via the first shake correction unit 50. Further, the lens device 10b is connected to the base member 13c via the mount member 13b of the lens device 10b and the mount member 13a of the main body 10a.

[0017] The first shake correction unit 50 corrects image blur caused by shake in the imaging system 10 by moving the imaging device 11 in a direction orthogonal to the optical axis 12a (the direction orthogonal to the optical axis) or rotating it within the plane 12c orthogonal to the optical axis, enabling a clear subject image to be obtained. Specifically, when the posture of the imaging system 10 changes with respect to the subject during imaging, the imaging position of the subject light beam on the imaging surface 11a of the imaging device 11 changes, causing blur in the image obtained through the imaging device 11. At this time, when the change in the posture of the imaging system 10 is sufficiently small, the change in the imaging position is uniform within the imaging surface 11a and can be regarded as translational or rotational movement (image plane blur) within the plane 12c orthogonal to the optical axis. Therefore, by translating or rotating the imaging device 11 within the plane 12c orthogonal to the optical axis so as to cancel the image plane blur, a clear subject image with corrected image blur can be obtained. When moving the imaging device 11 in a direction parallel to the imaging surface 11a, movement in a direction orthogonal to the imaging surface 11a may also be performed.

[0018] Similarly, the second shake correction unit 60 corrects image blur caused by shake in the imaging system 10 by moving the shake correction lens 12b in a direction orthogonal to the optical axis or rotating it within the plane 12c orthogonal to the optical axis, enabling a clear subject image to be obtained. That is, by moving the shake correction lens 12b in a direction orthogonal to the optical axis, the optical axis 12a is refracted. At this time, the shake correction lens 12b is moved in a direction orthogonal to the optical axis so that the image plane blur is canceled. Thereby, a clear subject image with corrected image blur can be obtained. Since the principle of shake correction by moving the imaging device 11 or the shake correction lens 12b is well-known, a more detailed description is omitted. Also, when moving the shake correction lens 12b in a direction orthogonal to the optical axis, movement in the optical axis direction may also be performed.

[0019] The first shake correction unit 50 includes a fixed part 20, a movable part 30, and a plurality of driving force generation parts. The fixed part 20 is fixed to the base member 13c, and the movable part holds the imaging element 11. The movable part 30 is supported by the fixed part 20 with three degrees of freedom, and can move in a direction orthogonal to the optical axis and rotate within the plane 12c orthogonal to the optical axis relative to the fixed part 20. That is, the first shake correction unit 50 is configured as a driving device (so-called XYθ stage) capable of driving control in three axes, and can move the imaging element 11 in a direction orthogonal to the optical axis and rotate it within the plane 12c orthogonal to the optical axis.

[0020] The second shake correction unit 60 includes a fixed part, a movable part, and a plurality of driving force generation parts. The fixed part is fixed to a housing (not shown) of the lens device 10b, and the movable part holds the shake correction lens 12b. The movable part is supported by the fixed part with two degrees of freedom, and can move in a direction orthogonal to the optical axis relative to the fixed part. That is, the second shake correction unit 60 is configured as a driving device (so-called XY stage) capable of driving control in two axes, and can move the shake correction lens 12b in a direction orthogonal to the optical axis.

[0021] The first vibration detection unit 16a and the second vibration detection unit 16b are each configured to include a gyro sensor, an acceleration sensor, or the like, and are shake detection means for detecting the angular velocity, acceleration, or the like in each direction of the imaging system 10 as shake information of the imaging system 10. The first shake correction control unit 15a and the second shake correction control unit 15b calculate the amount of angular change or movement in each direction of the imaging system 10 as shake information by integrating the angular velocity or acceleration detected by the first vibration detection unit 16a and the second vibration detection unit 16b. Further, the first shake correction control unit 15a calculates a movement target value of the imaging element 11 based on the shake information detected by the first vibration detection unit (first detection means) 16a, and controls the driving of the first shake correction unit 50. Thereby, the movement of the imaging element 11 can be controlled. Similarly, the second shake correction control unit 15b calculates a movement target value of the shake correction lens 12b based on the shake information detected by the second vibration detection unit 16b, and controls the driving of the second shake correction unit 60. Thereby, the movement of the shake correction lens 12b can be controlled.

[0022] Note that the imaging system 10 may be configured to include only one of the first shake correction unit 50 or the second shake correction unit 60. When the imaging system 10 does not include the first shake correction unit 50, the imaging element 11 is fixedly arranged with respect to the optical axis 12a. On the other hand, when the imaging system 10 does not include the second shake correction unit 60, basically the shake correction lens 12b is unnecessary. That is, the imaging optical system 12 of the lens device 10b is designed so that a desired optical characteristic can be obtained with a lens configuration that does not include the shake correction lens 12b.

[0023] Next, with reference to FIGS. 2 and 3, the detailed configuration of the shake correction unit (first shake correction unit 50) will be described. Since the configuration of the second shake correction unit 60 is the same as that of the first shake correction unit 50, its description will be omitted. FIGS. 2 and 3 are exploded perspective views of the first shake correction unit 50, respectively. FIG. 2 is a view of the first shake correction unit 50 as seen from the subject side, and FIG. 3 is a view of the first shake correction unit as seen from the image side. The first shake correction unit 50 includes a fixed part 20 and a movable part 30. In FIGS. 2 and 3, the movable part 30 is shown without being disassembled, and the fixed part 20 is shown disassembled.

[0024] The fixed part 20 has a base plate (fixed member) 21, a first rear yoke 22a, a second rear yoke 22b, a first rear magnet group 23a, a second rear magnet group 23b, and a third rear magnet group 23c. The base plate 21 is formed 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 fixed to the first rear yoke 22a and the second rear yoke 22b with an adhesive or the like, respectively. Also, the first rear magnet group 23a, the second rear magnet group 23b, and the third rear magnet group 23c are arranged so as to be surrounded by the first opening 21a, the second opening 21b, and the third opening 21c, respectively. The first rear yoke 22a and the second rear yoke 22b are fixed to the base plate 21 with screws.

[0025] In the present embodiment, as the first rear magnet group 23a, the second rear magnet group 23b, and the third rear magnet group 23c, two magnets magnetized in the optical axis direction (Z direction) are arranged so as to generate magnetic fields in opposite directions. However, the present embodiment is not limited to this, and one magnet magnetized in two poles may be used.

[0026] The fixing portion 20 also includes a first support member 24a, a second support member 24b, a third support member 24c, and a front yoke 25. The front yoke 25 is fixed to the base plate 21 with screws via the first support member 24a, the second support member 24b, and the third support member 24c. Also, the first support member 24a, the second support member 24b, and the third support member 24c are disposed at positions that restrict the movement of the movable portion 30, and are restricting portions that restrict the movement of the movable portion 30 within a predetermined range in the plane 12c orthogonal to the optical axis. At the contact portions of the first support member 24a, the second support member 24b, and the third support member 24c with the movable portion 30, a cushioning material such as rubber for absorbing the impact at the time of contact is provided, avoiding breakage and reducing the impact noise.

[0027] The first rear yoke 22a and the front yoke 25 are arranged so as to sandwich the first rear magnet group 23a in the optical axis direction, and the first rear magnet group 23a forms a first magnetic circuit passing through the first rear yoke 22a and the front yoke 25. Similarly, the second rear yoke 22b and the front yoke 25 are arranged so as to sandwich the second rear magnet group 23b and the third rear magnet group 23c in the optical axis direction. The second rear magnet group 23b and the third rear magnet group 23c respectively form a second magnetic circuit and a third magnetic circuit.

[0028] The fixing portion 20 also includes a first thrust yoke (first yoke member) 27, a fixing sheet metal 28, and a base member 29. The first thrust yoke 27 is disposed at a position facing a thrust magnet (magnet member) 38 described later, and is fastened to the fixing sheet metal 28 with screws. The fixing sheet metal 28 is fixed to the base plate 21 with screws or an adhesive (not shown). In the present embodiment, the first thrust yoke 27 is composed of a single component, but it may be integrally formed with the base plate 21. In that case, the base plate 21 is formed of a magnetic material and the fixing sheet metal 28 is unnecessary. The base member 29 is fixed to the base plate 21 with screws together with the second rear yoke 22b, and a drive FPC (flexible printed circuit) 34a described later is attached thereto.

[0029] Next, with reference to FIGS. 4 and 5, a detailed configuration of the movable unit 30 that constitutes the blur correction unit will be described. FIGS. 4 and 5 are exploded perspective views of the movable unit 30. FIG. 4 is a view of the movable unit 30 as seen from the subject side, and FIG. 5 is a view of the movable unit 30 as seen from the image side.

[0030] The movable unit 30 includes an imaging element 11 and a holding member (movable member) 31 that holds the imaging element 11. The imaging element 11 is fixed to the holding member 31 with an adhesive or the like. The holding member 31 is movable in a direction orthogonal to the optical axis 12a with respect to the base plate 21.

[0031] The movable unit 30 also includes a mask 32a, an infrared absorption filter 32b, an optical low-pass filter 32c, and a vibration unit 32d. The mask 32a, the infrared absorption filter 32b, and the optical low-pass filter 32c are held by a holder member 32e and a holder sheet metal 32f, and are fixed to the imaging element 11 with an adhesive member or the like. The mask 32a prevents unnecessary light from entering the imaging element 11 from outside the imaging optical path. The optical low-pass filter 32c reduces moire caused by the repeating pattern of the subject. The vibration unit 32d is provided on the optical low-pass filter 32c, and removes foreign matter such as dust adhering to the surface of the optical low-pass filter 32c by vibrating the optical low-pass filter 32c. Since the principle and control of foreign matter removal by the vibration unit 32d are known, detailed description thereof is omitted.

[0032] The movable unit 30 also includes a first coil 33a, a second coil 33b, a third coil 33c, and a drive FPC 34a. The drive FPC 34a is arranged 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 holding member 31 with screws, an adhesive, or the like.

[0033] The holding member 31 has a first concave portion 31a, a second concave portion 31b, and a third concave portion 31c. The first coil 33a, the second coil 33b, and the third coil 33c are respectively disposed inside the first concave portion 31a, the second concave portion 31b, and the third concave portion 31c, and are fixed to the holding member 31 with an adhesive or the like.

[0034] The first magnetic circuit (the first rear magnet group 23a) and the first coil 33a form a VCM as a first actuator. The second magnetic circuit (the second rear magnet group 23b) and the second coil 33b form a VCM as a second actuator. The third magnetic circuit (the third rear magnet group 23c) and the third coil 33c form a VCM as a third actuator. The first actuator, the second actuator, and the third actuator constitute a driving unit that drives the holding member 31.

[0035] A Lorentz force is generated in a direction orthogonal to the magnetic field generated in the optical axis direction in the first magnetic circuit and the current flowing through the first coil 33a, and the resultant force direction of the Lorentz force changes according to the energization direction of the first coil 33a. Similar Lorentz forces are also generated in the second magnetic circuit and the second coil 33b, and the third magnetic circuit and the third coil 33c. The first actuator generates a translational force in the X direction. The second actuator and the third actuator generate forces substantially parallel to the Y direction, and the translational force in the Y direction is generated by the sum of the respective forces, and the rotational force around the optical axis is generated by the difference between the respective forces.

[0036] Next, with reference to FIG. 6, the configuration of the driving FPC 34a constituting the movable portion 30 will be described. FIG. 6 is a perspective view of the driving FPC 34a. A first detection element 35a, a second detection element 35b, and a third detection element 35c are attached to the driving FPC 34a. The first detection element 35a, the second detection element 35b, and the third detection element 35c are second detection means for detecting relative position information of the holding member 31 with respect to the base plate 21.

[0037] The first detection element 35a is disposed inside the first coil 33a, the second detection element 35b is disposed inside the second coil 33b, and the third detection element 35c is disposed inside the third coil 33c. The first detection element 35a, the second detection element 35b, and the third detection element 35c are, for example, Hall elements. The first detection element 35a detects the magnetic force of the first magnetic circuit, and the first shake correction control unit 15a calculates position information (specifically, the position and the angle around the optical axis) of the movable part 30 relative to the fixed part 20 in the plane perpendicular to the optical axis 12c based on the detection result of the first detection element 35a. The same is true for each of the second detection element 35b and the third detection element 35c.

[0038] The first coil 33a, the second coil 33b, and the third coil 33c are electrically connected to the driving FPC 34a, and the first shake correction control unit 15a controls the current flowing through each coil via the driving FPC 34a. That is, the first shake correction control unit 15a performs feedback control based on the deviation between the movement target value of the image sensor 11 based on the shake correction information detected by the first vibration detection unit 16a and the current position information of the image sensor 11 detected by each detection element (Hall element). In this way, the first shake correction control unit 15a controls the drive of the movable unit 30.

[0039] The movable part 30 is supported by the base plate 21 via balls (rolling members) 26a, 26b, and 26c so as to be movable within the optical axis perpendicular plane 12c. The balls 26a, 26b, and 26c are respectively disposed inside a first enclosure 31d, a second enclosure 31e, and a third enclosure 31f provided in the holding member 31. When the movable part 30 moves within the optical axis perpendicular plane 12c relative to the fixed part 20, the balls 26a, 26b, and 26c roll, so that the load due to friction between the holding member 31 and the base plate 21 is small.

[0040] The movable part 30 also has a thrust magnet 38 and a second thrust yoke (second yoke member) 37. The thrust magnet 38 and the second thrust yoke 37 are arranged at positions facing the first thrust yoke 27 arranged on the fixed part 20, and are fixed to the holding member 31 with screws, adhesives, etc. not shown in the figure. The thrust magnet 38 forms a fourth magnetic circuit passing through the first thrust yoke 27 and the second thrust yoke 37. The movable part 30 is biased in the optical axis direction (-Z direction) toward the base plate 21 by the attractive force generated between the thrust magnet 38 and the first thrust yoke 27. That is, the thrust magnet 38, the first thrust yoke 27, and the second thrust yoke 37 constitute a first biasing part that biases the movable part 30 in the optical axis direction (-Z direction) toward the fixed part 20.

[0041] The movable part 30 also has a first thrust sheet metal 36a and a second thrust sheet metal 36b. The first thrust sheet metal 36a is arranged at a position facing the first rear magnet group 23a, and the second thrust sheet metal 36b is arranged at a position facing the third rear magnet group 23c, and is fixed to the drive FPC 34a with an adhesive or the like. The first thrust sheet metal 36a and the second thrust sheet metal 36b are formed of a magnetic material and generate an attractive force between the opposing first rear magnet group 23a and the second rear magnet group 23b. That is, the first thrust sheet metal 36a and the second thrust sheet metal 36b respectively constitute a second biasing part and a third biasing part that bias the movable part 30 toward the fixed part 20.

[0042] The first biasing part, the second biasing part, and the third biasing part are arranged such that the center of gravity of the movable part 30 is located inside the triangle formed by connecting the respective biasing parts in the plane 12c orthogonal to the optical axis. The same applies to the arrangement of the balls 26a, 26b, and 26c. As a result, a biasing force can be generated on the movable part 30 in a well-balanced manner. Therefore, it is possible to prevent the movable part 30 from floating up during driving.

[0043] Next, with reference to FIGS. 7(a) to 7(c), the first biasing portion (holding assist configuration) composed of the thrust magnet 38, the first thrust yoke 27, and the second thrust yoke 37 will be described in detail. FIG. 7(a) is a perspective view of the first vibration correction unit 50, FIG. 7(b) is a front view of the first vibration correction unit 50, and FIG. 7(c) is a cross-sectional view taken along line A-A in FIG. 7(b). In FIGS. 7(a) to 7(c), only the components related to the description of the first biasing portion are excerpted and shown.

[0044] As described above, the first thrust yoke 27 is fixed to the base plate 21 that constitutes the fixed portion 20, and the thrust magnet 38 and the second thrust yoke 37 are arranged on the holding member 31 that constitutes the movable portion 30.

[0045] As shown in FIG. 7(c), the first thrust yoke 27 and the second thrust yoke 37 have a first surface 27a and a second surface 37a that overlap (oppose) each other on the projection plane in the vertical direction (Y direction) and are close to each other in the vertical direction (Y direction). Also, the first thrust yoke 27 and the second thrust yoke 37 have a third surface 27b and a fourth surface 37b that overlap (oppose) each other on the projection plane in the optical axis direction (Z direction). Further, the first thrust yoke 27 has a first connecting portion 27c that connects the first surface 27a and the third surface 27b. Similarly, the second thrust yoke 37 has a second connecting portion 37c that connects the second surface 37a and the fourth surface 37b.

[0046] The thrust magnet 38 is arranged so as to abut on the fourth surface 37b of the second thrust yoke 37 and is fixed to the second thrust yoke 37 with screws, adhesives, etc. not shown. Also, the thrust magnet 38 is arranged such that the magnetization direction is parallel to the optical axis direction (Y direction). Therefore, as shown by the broken line arrow in FIG. 7(c), the thrust magnet 38 forms a fourth magnetic circuit passing through the first thrust yoke 27 and the second thrust yoke 37.

[0047] The fourth magnetic circuit generates an attractive force (second biasing force) F2 between the thrust magnet 38 and the third surface 27b of the first thrust yoke 27. The movable part 30 is biased toward the base plate 21 by the attractive force F2.

[0048] Also, the fourth magnetic circuit generates an attractive force (first biasing force) F1 between the first surface 27a of the first thrust yoke 27 and the second surface 37a of the second thrust yoke 37. In the present embodiment, the first surface 27a (one surface of the fixed part 20) is arranged above the second surface 37a (one surface of the movable part 30) in the vertical direction (Y direction). Thereby, the attractive force F1 can be generated in the +Y direction (the direction opposite to the gravitational direction at the positive position). That is, since the attractive force F1 can be made to act in the direction canceling the self-weight of the movable part 30, it becomes possible to reduce the driving force of the VCM necessary for holding the movable part 30 (holding assist effect). Therefore, the power consumption associated with holding the movable part 30 can be reduced. Also, the means for generating the attractive force F1 is by utilizing the magnetic circuit of the first biasing part. Therefore, since no additional dedicated parts or mechanisms are required, it can be realized without increasing the size of the first blur correction unit 50 and the number of parts.

[0049] Note that within the drive control range of the movable part 30, it is desirable that the attractive force F1 is always set to be smaller than the self-weight of the movable part 30. That is, within the drivable range of the holding member 31 by the drive part, the attractive force F1 is smaller than the gravitational force acting on the holding member 31. For example, when the attractive force F1 exceeds the self-weight of the movable part 30, the movable part 30 is biased in the +Y direction by the attractive force F1. Therefore, it becomes a driving load when driving the movable part 30, and there is a possibility that the drive controllability (i.e., anti-vibration controllability) of the movable part 30 deteriorates. Therefore, by setting the attractive force F1 to always be smaller than the self-weight of the movable part 30, the power consumption can be reduced without deteriorating the drive controllability of the movable part 30.

[0050] Also, in the present embodiment, although the thrust magnet 38 is disposed on the movable part 30 (the fourth surface 37b), it is not limited thereto. Even when the thrust magnet 38 is disposed on the fixed part 20 (the third surface 27b), since the attractive forces F2 and F1 act in the same manner, they may be disposed on the fixed part 20 (the third surface 27b).

[0051] Here, with reference to FIG. 8, a modified example of the present embodiment will be described. FIG. 8 is a cross-sectional view of a first biasing part (holding assist configuration) as a modified example, and shows an example in which the thrust magnet 38 in FIG. 7(d) is disposed on the first surface 27a of the first thrust yoke 27. As shown in FIG. 8, the thrust magnet 38 may be disposed on the first surface 27a or the second surface 37a so that the magnetization direction of the thrust magnet 38 is parallel to the vertical direction (Y direction). Even in the configuration shown in FIG. 8, a magnetic circuit equivalent to the fourth magnetic circuit in FIG. 7(d) can be configured, and the attractive forces F2 and F1 can be made to act in the same manner.

[0052] As described above, in the present embodiment, the thrust magnet 38 is disposed on one of the third surface 27b and the fourth surface 37b such that the magnetization direction coincides with the second direction. However, the present embodiment is not limited thereto, and as in the modified example described with reference to FIG. 8, the thrust magnet 38 may be disposed on one of the first surface 27a and the second surface 37a such that the magnetization direction coincides with the first direction. In any arrangement, the holding member 31 is biased in the first direction toward the base plate 21 via the first surface 27a and the second surface 37a by the first biasing force. Also, the holding member 31 is biased in the second direction toward the base plate 21 via the third surface 27b and the fourth surface 37b by the second biasing force.

[0053] Next, with reference to FIG. 9, the shapes of the first thrust yoke 27 and the second thrust yoke 37 will be described. FIG. 9 is a top view (projection view) of the first biasing portion as viewed from the +Y direction. The hatched portion A1 in FIG. 9 is the first surface 27a of the first thrust yoke 27 and the second surface 37a of the second thrust yoke 37 that overlap each other on the projection plane in the vertical direction (Y direction).

[0054] The hatched portion A2 in FIG. 9 is the opening 27e formed in the first connecting portion 27c of the first thrust yoke 27. The opening 27e is provided so that the first connecting portion 27c of the first thrust yoke 27 and the second connecting portion 37c of the second thrust yoke 37 do not overlap each other on the projection plane in the vertical direction (Y direction). By providing the opening 27e, the distance between the first connecting portion 27c and the second connecting portion 37c can be increased, and the magnetic flux passing through the first thrust yoke 27 can be reduced from leaking between the first connecting portion 27c and the second connecting portion 37c. Therefore, a decrease in the attractive force F1 due to magnetic flux leakage can be suppressed, and the holding assist effect can be efficiently exhibited.

[0055] Here, the length of the opening 27e in the horizontal direction (X direction, third direction) is defined as L1, the length of the second surface 37a of the second thrust yoke 37 in the horizontal direction (X direction) is defined as L2, and the maximum driving amount of the movable portion 30 in the horizontal direction (X direction) is defined as L3 (not shown). In the present embodiment, the opening 27e is formed so as to satisfy the conditional expression L1 > L2 + L3. By satisfying this conditional expression, within the control range (drivable range) of the movable portion 30, it is possible to prevent the second surface 37a of the second thrust yoke 37 from overlapping the first connecting portion 27c of the first thrust yoke 27 in the vertical direction (Y direction). Thereby, the area where the attractive force F1 acts (the area where the first surface 27a and the second surface 37a overlap each other in the vertical direction (first area)) can be made constant. Therefore, the generation of the force component of the attractive force F1 in the horizontal direction (X direction) can be suppressed, and the drive controllability (i.e., anti-vibration controllability) of the movable portion 30 can be improved.

[0056] Further, an end portion 37d of the second thrust yoke 37 in the optical axis direction (+Z direction) of the second surface 37a is disposed outside in the optical axis direction (+Z direction) than an end portion 27d of the first surface 27a of the first thrust yoke 27 in the optical axis direction (+Z direction). When the end portion 37d of the second surface 37a is provided inside the end portion 27d of the first surface 27a, since a magnetic force acts from the first surface 27a toward the second surface 37a, an attractive force F1 is generated obliquely with respect to the vertical direction (Y direction). Therefore, the holding assist effect of the attractive force F1 in the vertical direction (Y direction) is reduced. Further, in order to generate a force component in the opposite direction (+Z direction) with respect to the attractive force F2, a sufficient biasing force may not be obtained, or the thrust magnet 38 may need to be enlarged in order to secure a necessary biasing force. Considering such a possibility, by providing the end portion 37d of the second surface 37a outside the end portion 27d of the first surface 27a, an efficient magnetic circuit can be configured.

[0057] Next, with reference to FIGS. 10(a) to 10(c), the relationship between the thrust magnet 38 and the third surface 27b of the first thrust yoke 27 will be described. FIGS. 10(a) to 10(c) are front views of the first biasing portion as viewed from the +Z direction in the normal position posture of the imaging system 10. FIG. 10(a) shows a state where the movable portion 30 is held at a position substantially coinciding with the optical axis 12a (i.e., held at the center). FIG. 10(b) shows a state where the movable portion 30 has moved to the maximum position movable in the -Y direction within the control range of the movable portion 30. FIG. 10(c) shows a state where the energization of the first coil 33a, the second coil 33b, and the third coil 33c is turned off (i.e., the power-off state of the imaging system 10). At this time, the movable portion 30 is in contact with and stationary on any one of the first support member 24a, the second support member 24b, or the third support member 24c.

[0058] In the state of FIG. 10(a), an area of a region overlapping with each other on the projection plane in the optical axis direction (Z direction) between the thrust magnet 38 and the third surface 27b of the first thrust yoke 27 is defined as S1. Similarly, the area in the state of FIG. 10(b) is defined as S2, and the area in the state of FIG. 10(c) is defined as S3.

[0059] As shown in FIGS. 10(a) and 10(b), it is desirable that the thrust magnet 38 be arranged such that the area overlapping with the third surface 27b in the optical axis direction (Z direction) of the thrust magnet 38 is constant (S1 = S2) within the control range of the movable part 30. That is, it is desirable that the size of the area (second area) where the third surface 27b or the fourth surface 37b facing the thrust magnet 38 with a certain gap and the thrust magnet 38 overlap each other in the optical axis direction (second direction) be constant.

[0060] By making the area constant, when driving the movable part 30, the generation of the force component of the attractive force F2 acting on the thrust magnet 38 in the direction orthogonal to the optical axis (XY plane direction) can be suppressed, and the driving controllability (i.e., anti-vibration controllability) of the movable part 30 can be improved. Further, in FIG. 10(b), only the state where the movable part 30 has moved to the maximum position in the -Y direction within the control range is shown, but it is not limited to that position, and it is desirable that the area be constant throughout the control range within the plane orthogonal to the optical axis 12c (within the XY plane). Thereby, throughout the entire control range of the movable part 30, a decrease in driving controllability due to the generation of the force component of the attractive force F2 in the direction orthogonal to the optical axis (XY plane direction) can be suppressed.

[0061] On the other hand, as shown in FIG. 10(c), in the state where the power of the imaging system 10 is OFF, it is desirable that the -Y direction end portion (lower end portion) 38a of the thrust magnet 38 be located below the -Y direction end portion (lower end portion) 27f of the third surface 27b of the first thrust yoke 27. That is, in the state where the holding member 31 abuts against the restricting portions (24a to 24c) due to the downward movement of the holding member 31, it is desirable that the end portion 38a be located on the side of the end portion 27f of the third surface 27b or the fourth surface 37b facing the thrust magnet 38 with a certain gap.

[0062] At this time, the area where the thrust magnet 38 overlaps with the third surface 27b in the optical axis direction (Z direction) in the power-off state is smaller than the area within the control range of the movable part 30, that is, S3 < S1 = S2. When the above relationship is satisfied, a force component in the +Y direction (the anti-gravity direction at the positive position) is generated in the attractive force F2 acting on the thrust magnet 38. Therefore, in the power-off state, the attractive force F2 can be applied in the direction to cancel the self-weight of the movable part 30. For this reason, it is possible to reduce the driving force of the VCM required for the return operation of the imaging device 10 from the power-off state (Fig. 10(c)) to the center holding state (Fig. 10(a)) by turning on the power (return assist effect). Therefore, the power consumption associated with the return operation of the movable part 30 can be reduced.

[0063] As described above, in the present embodiment, the first surface 27a of the first thrust yoke 27 and the second surface 37a of the second thrust yoke 37 overlap with each other in the first direction (Y direction) perpendicular to the optical axis direction (Z direction). Also, the third surface 27b of the first thrust yoke 27 and the fourth surface 37b of the second thrust yoke 37 overlap with each other in the second direction (Z direction) parallel to the optical axis 12a. Further, the thrust magnet 38, the first thrust yoke 27, and the second thrust yoke 37 constitute a magnetic circuit passing through the first surface 27a, the second surface 37a, the third surface 27b, and the fourth surface 37b.

[0064] Preferably, the first direction is parallel to the gravity direction (-Y direction) in a state where the main body portion 10a is at a predetermined position, and the first surface 27a is disposed on the side opposite to the gravity direction (upper side) with respect to the second surface 37a. Also preferably, the predetermined position is the positive position of the main body portion 10a, and the first direction is the height direction of the main body portion 10a. Also preferably, the first surface 27a and the second surface 37a face each other in the first direction, and the third surface 27b and the fourth surface 37b face each other in the second direction.

[0065] According to the present embodiment, it is possible to provide an imaging device capable of reducing power consumption regardless of the posture with a simple configuration.

[0066] The disclosure of each embodiment includes the following configuration. (Configuration 1) A fixed member, A movable member that holds an imaging element and is movable in a direction orthogonal to the optical axis with respect to the fixed member, A driving unit that drives the movable member, A rolling member disposed between the fixed member and the movable member, A first yoke member disposed on the fixed member, A second yoke member disposed on the movable member, And a magnet member disposed on one of the first yoke member and the second yoke member, A first surface of the first yoke member and a second surface of the second yoke member overlap each other in a first direction perpendicular to the optical axis direction, A third surface of the first yoke member and a fourth surface of the second yoke member overlap each other in a second direction parallel to the optical axis, The imaging device, wherein the magnet member, the first yoke member, and the second yoke member constitute a magnetic circuit passing through the first surface, the second surface, the third surface, and the fourth surface. (Configuration 2) The first direction is parallel to the direction of gravity in a state where the imaging device is at a predetermined position, The imaging device according to Configuration 1, wherein the first surface is disposed on a side opposite to the second surface with respect to the direction of gravity. (Configuration 3) The predetermined position is the correct position of the imaging device, The imaging device according to Configuration 2, wherein the first direction is the height direction of the imaging device. (Configuration 4) The first surface and the second surface face each other in the first direction, The imaging device according to any one of Configurations 1 to 3, wherein the third surface and the fourth surface face each other in the second direction. (Configuration 5) The magnet member is disposed on one of the third surface or the fourth surface such that the magnetization direction thereof coincides with the second direction. The movable member is biased in the first direction toward the fixed member via the first surface and the second surface by a first biasing force. The imaging device according to any one of Configurations 1 to 4, wherein the movable member is biased in the second direction toward the fixed member via the third surface and the fourth surface by a second biasing force. (Configuration 6) The imaging device according to Configuration 5, wherein in a drivable range of the movable member by the drive unit, the first biasing force is smaller than the gravitational force acting on the movable member. (Configuration 7) The first yoke member has a first connection portion connecting the first surface and the third surface. The second yoke member has a second connection portion connecting the second surface and the fourth surface. The imaging device according to any one of Configurations 1 to 6, wherein an opening is formed in the first connection portion so that the first connection portion and the second connection portion do not overlap each other in the first direction. (Configuration 8) The imaging device according to Configuration 7, wherein in a drivable range of the movable member by the drive unit, the opening is formed such that a first area where the first surface and the second surface overlap each other in the first direction is constant. (Configuration 9) The imaging device according to any one of Configurations 1 to 8, wherein in the second direction, an end portion of the second surface is disposed outside an end portion of the first surface. (Configuration 10) The imaging device according to any one of Configurations 1 to 9, wherein in a drivable range of the movable member by the drive unit, a magnitude of a second area where the third surface or the fourth surface facing the magnet member with a certain gap and the magnet member overlap each other in the second direction is constant. (Configuration 11) further comprising a restricting portion that restricts the movement of the movable member, in a state where the movable member abuts against the restricting portion due to downward movement of the movable member in the first direction, a lower end portion of the magnet member in the first direction is located below the lower end portion of the third surface or the fourth surface that faces the magnet member with a certain gap in the first direction. The imaging device according to any one of Configurations 1 to 10. (Configuration 12) the magnet member is disposed on one of the first surface or the second surface such that the magnetization direction coincides with the first direction, the movable member is biased in the first direction toward the fixed member via the first surface and the second surface by a first biasing force, the movable member is biased in the second direction toward the fixed member via the third surface and the fourth surface by a second biasing force. The imaging device according to any one of Configurations 1 to 4. (Configuration 13) further comprising control means for controlling the driving portion, the driving portion includes a coil held by the movable member, a magnet member held by the fixed member, first detection means for detecting shake information of the fixed member, second detection means for detecting relative position information of the movable member with respect to the fixed member, and the control means controls the movable member based on the shake information and the position information. The imaging device according to any one of Configurations 1 to 12.

[0067] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist. Furthermore, each of the above-described embodiments merely shows one embodiment of the present invention, and it is also possible to appropriately combine the embodiments.

[0068] For example, regarding the magnet and coil that constitute the VCM which is an actuator, it suffices that one of the magnet and coil is arranged on the fixed part and the other is arranged on the movable part.

Explanation of Signs

[0069] 10a Main body part (imaging device) 11 Imaging element 21 Base plate (fixed member) 23a, First rear magnet group (drive part) 23b Second rear magnet group (drive part) 23c Third rear magnet group (drive part) 26a, 26b, 26c Balls (rolling members) 27 First thrust yoke (first yoke member) 27a First surface 27b Third surface 31 Holding member (movable member) 33a First coil (drive part) 33b Second coil (drive part) 33c Third coil (drive part) 37 Second thrust yoke (second yoke member) 37a Second surface 37b Fourth surface 38 Thrust magnet (magnet member)

Claims

1. A fixed member, a movable member that holds an imaging element and is movable in a direction perpendicular to the optical axis with respect to the fixed member, a driving unit that drives the movable member, a rolling member disposed between the fixed member and the movable member, a first yoke member disposed on the fixed member, a second yoke member disposed on the movable member, and a magnet member disposed on one of the first yoke member and the second yoke member, wherein a first surface of the first yoke member and a second surface of the second yoke member overlap each other in a first direction perpendicular to the optical axis direction, a third surface of the first yoke member and a fourth surface of the second yoke member overlap each other in a second direction parallel to the optical axis, and the magnet member, the first yoke member, and the second yoke member constitute a magnetic circuit passing through the first surface, the second surface, the third surface, and the fourth surface. An imaging device characterized by this.

2. The first direction is parallel to the gravitational direction in a state where the imaging device is in a predetermined position, and the first surface is disposed on a side opposite to the gravitational direction with respect to the second surface. The imaging device according to claim 1, characterized by this.

3. The predetermined position is the normal position of the imaging device, and the first direction is the height direction of the imaging device. The imaging device according to claim 2, characterized by this.

4. The first surface and the second surface face each other in the first direction, and the third surface and the fourth surface face each other in the second direction. The imaging device according to claim 1, characterized by this.

5. The magnet member is disposed on one of the third surface or the fourth surface such that the magnetization direction coincides with the second direction, the movable member is biased in the first direction toward the fixed member via the first surface and the second surface by a first biasing force, and the movable member is biased in the second direction toward the fixed member via the third surface and the fourth surface by a second biasing force. The imaging device according to any one of claims 1 to 4, characterized by this.

6. In a drivable range of the movable member by the driving unit, the first biasing force is smaller than the gravity acting on the movable member. The imaging device according to claim 5, characterized by this.

7. The first yoke member has a first connection portion that connects the first surface and the third surface, The second yoke member has a second connecting portion that connects the second surface and the fourth surface, The imaging device according to any one of claims 1 to 4, wherein an opening is formed in the first connecting portion so that the first connecting portion and the second connecting portion do not overlap each other in the first direction.

8. The imaging device according to claim 7, wherein the opening is formed so that a first area where the first surface and the second surface overlap each other in the first direction is constant within a drivable range of the movable member by the driving unit.

9. The imaging device according to any one of claims 1 to 4, wherein an end portion of the second surface is disposed outside an end portion of the first surface in the second direction.

10. The imaging device according to any one of claims 1 to 4, wherein a size of a second area where the third surface or the fourth surface facing the magnet member with a constant gap and the magnet member overlap each other in the second direction is constant within a drivable range of the movable member by the driving unit.

11. The imaging device further includes a restricting portion that restricts movement of the movable member, In a state where the movable member abuts against the restricting portion due to downward movement of the movable member in the first direction, a lower end portion of the magnet member in the first direction is located below a lower end portion of the third surface or the fourth surface facing the magnet member with a constant gap in the first direction. The imaging device according to any one of claims 1 to 4, characterized in that.

12. The magnet member is disposed on one of the first surface or the second surface so that a magnetization direction thereof coincides with the first direction, The movable member is biased in the first direction toward the fixed member via the first surface and the second surface by a first biasing force, The imaging device according to any one of claims 1 to 4, wherein the movable member is biased in the second direction toward the fixed member via the third surface and the fourth surface by a second biasing force.

13. The imaging device further includes control means for controlling the driving unit, The driving unit is A coil held by the movable member, A magnet member held by the fixed member, First detection means for detecting blur information of the fixed member, a second detecting means for detecting relative position information of the movable member with respect to the fixed member; The imaging apparatus according to any one of claims 1 to 4, wherein the control means controls the movable member based on the shake information and the position information.

Images