Image blur correction device, imaging device, and lens device

A first image blur correction device includes an imaging-element holding-member to which an imaging-element is fixed, a housing that supports the imaging-element holding-member to be movable in a direction X perpendicular to an optical axis of a lens device, and a first drive mechanism that generates thrust of moving the imaging-element holding-member in the direction X. The first drive mechanism includes a first magnet that is fixed to the housing and in which a direction connecting both magnetic poles is parallel to the direction X, and a first coil that is fixed to the imaging-element holding-member to face the first magnet. In a state where the imaging-element holding-member is at a reference position where the optical axis of the lens device coincides with a center of the imaging-element, a position of a first magnet center in the direction X and a first coil central axis deviate from each other.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image blur correction device, an imaging device, and a lens device.

2. Description of the Related Art

As an imaging device including an imaging element that images a subject through an imaging optical system or a lens device that is mounted in such an imaging device for use, a device that has an image blur correction function of correcting blur (hereinafter, referred to as image blur) of an image formed in the imaging element by the imaging optical system caused by vibration of the device is known.

JP2009-53673A describes an image blur correction device that uses a voice coil motor as a drive source for moving a moved member at the time of image blur correction. The voice coil motor consists of a magnet, a coil facing the magnet, and a yoke.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an image blur correction device capable of achieving improvement of thrust while suppressing an increase in size of the device, and an imaging device and a lens device comprising the image blur correction device.

An image blur correction device of the present invention is an image blur correction device that corrects blur of an image formed in an imaging element by an imaging optical system. The image blur correction device comprises a movable mechanism to which an optical component included in the imaging element or the imaging optical system is fixed, a support mechanism that supports the movable mechanism to be movable in a first direction perpendicular to an optical axis of the imaging optical system, and a first drive mechanism that generates thrust of moving the movable mechanism in the first direction. The first drive mechanism includes a first magnetic force generator that is fixed to one mechanism of the support mechanism and the movable mechanism and in which a direction connecting both magnetic poles is parallel to the first direction, and a first coil that is fixed to the other mechanism of the support mechanism and the movable mechanism to face the first magnetic force generator. In a state in which the movable mechanism is at a reference position where the optical axis of the imaging optical system coincides with a center of the imaging element, a position in the first direction of a center between both magnetic poles of the first magnetic force generator and a central axis of winding of the first coil deviate from each other.

An imaging device of the present invention is an imaging device comprising the image blur correction device. The imaging element is fixed to the movable mechanism.

A lens device of the present invention is a lens device comprising the image blur correction device. The optical component is fixed to the movable mechanism.

According to the present invention, it is possible to provide an image blur correction device capable of achieving improvement of thrust while suppressing an increase in size of the device, and an imaging device and a lens device comprising the image blur correction device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described referring to the drawings.

Imaging Device Comprising Image Blur Correction Device of First Embodiment

For example, a lens device performs image blur correction by detecting vibration of the device based on information from a movement detection sensor, such as an acceleration sensor or an angular velocity sensor mounted in the lens device, and moving a correction lens included in an imaging optical system within a plane perpendicular to an optical axis to counteract the detected vibration.

Furthermore, an imaging device performs image blur correction by detecting vibration of the device based on information from a movement detection sensor, such as an acceleration sensor or an angular velocity sensor mounted in the imaging device and moving one or both of a correction lens included in an imaging optical system and an imaging element within a plane perpendicular to an optical axis to counteract the detected vibration.

In a case where a voice coil motor is used to move one or both of the correction lens included in the imaging optical system and the imaging element within the plane perpendicular to the optical axis, in general, a configuration in which a magnet and a coil are disposed such that the center between both magnetic poles in the magnet and a central axis of winding of the coil overlap each other is commonly used to efficiently generate thrust.

In such a voice coil motor, in a case where a winding number of the coil is increased or the magnet is increased in size to obtain greater thrust, the image blur correction device including the voice coil motor is increased in size.

In a case where the image blur correction device is increased in size, the imaging device comprising the image blur correction device or the lens device comprising the image blur correction device is increased in size.

Although a technique for mounting a yoke in a narrow space with high density to achieve reduction in size of a drive mechanism while maintaining drive power is known, the technique does not take into consideration obtaining large thrust while suppressing an increase in size of the image blur correction device.

FIG.1is a transparent perspective view schematically showing an imaging device100comprising a first image blur correction device130that is a first embodiment of an image blur correction device of the present invention.

The imaging device100ofFIG.1is a digital camera that stores an image formed in an imaging element120by the lens device110including a lens, a stop, and the like as digital image data. The imaging element120is configured with, for example, a solid-state imaging element, such as a complementary metal-oxide-semiconductor (CMOS)-type image sensor or a charge-coupled device (CCD)-type image sensor.

The imaging device100may be a still camera that stores data of a static image, may be a video camera that stores data of video, or may be a camera that has both functions.

The first image blur correction device130is mounted in the imaging device100and corrects image blur that occurs during exposure by the imaging element120. Image blur is blurring of the image formed in the imaging element120by the lens device110. Image blur occurs, for example, due to vibration of the imaging device100caused by shake or the like of a hand of a user who holds the imaging device100.

In the embodiment, the first image blur correction device130performs so-called sensor shift-type image blur correction to correct image blur by moving the imaging element120. A configuration in which so-called lens shift-type image blur correction to correct image blur by moving the lens included in the lens device110is performed will be described below referring toFIG.9.

Here, a direction parallel to an optical axis111of the lens device110is referred to as a direction Z, a direction parallel to a longitudinal direction of the imaging element120between directions perpendicular to the direction Z is referred to as a direction X, and a direction perpendicular to the direction Z and the direction X is referred to as a direction Y. In the direction Y, upward inFIG.1is referred to as an upper side and downward inFIG.1is referred to as a lower side.

The first image blur correction device130correct image blur in the direction X and the direction Y by moving the imaging element120in the direction X and the direction Y. Alternatively, the first image blur correction device130may correct image blur in a rotation direction around the direction Z by rotating the imaging element120around an axis of the direction Z.

In the imaging device100, each lens included in the lens device110configures an imaging optical system.

FIG.2is a schematic planar sectional view as the imaging device100ofFIG.1is viewed in the direction Y from above. The lens device110is omitted inFIG.2. InFIG.2, a cross section of the imaging device100passing through the optical axis111is shown.

The imaging device100comprises the lens device110(not shown), the imaging element120, the first image blur correction device130, a first housing201, a first mount202, a battery box203, a first main board204, a shutter unit205, and a liquid crystal display206. In an example shown inFIG.2, the imaging device100is a body of a digital camera in which the lens device110is interchangeable. Note that the imaging device100may be a digital camera in which the body and the lens device110are integrated.

The first housing201houses components of the imaging device100including the imaging element120, the first image blur correction device130, the battery box203, the first main board204, the shutter unit205, and the like.

The first mount202is provided as an opening portion of the first housing201and is a mechanism for attaching and detaching the lens device110. The lens device110is connected to the first mount202, whereby light passing through the lens device110is formed in the imaging element120as an image.

The battery box203houses a battery and supplies power to respective electronic components of the imaging device100, such as the imaging element120, the first image blur correction device130, the first main board204, the shutter unit205, and the liquid crystal display206.

The first main board204is a control circuit that controls the respective electronic components of the imaging device100, such as the imaging element120, the first image blur correction device130, the first main board204, the shutter unit205, and the liquid crystal display206.

The shutter unit205has a shutter section205athat is provided between the first mount202and the imaging element120, and a shutter drive section205bthat controls opening and closing of the shutter section205a.The opening and closing of the shutter section205aare controlled by the shutter drive section205b,whereby a time for which the imaging element120is exposed to light passing through the lens device110, that is, an exposure time is controlled.

The liquid crystal display206is provided on a surface opposite to a surface on which the first mount202is provided, in the external surface of the first housing201. For example, the liquid crystal display206displays various kinds of setting information, such as an exposure value, an F number, a shutter speed, and sensitivity set in the imaging device100, an image obtained by imaging, and the like to the user. The liquid crystal display206may be a touch panel that has a function of receiving an operation from the user through a touch operation along with the above-described display function.

The first image blur correction device130comprises a base131, a first yoke Y1, a second yoke Y2, a first magnet M1, a first coil C1, an imaging element holding member132, flexible printed circuits (FPC)133, and a first hall element H1.

The base131is a rectangular flat plate-shaped member in which a thickness direction is parallel to the direction Z, and is provided in an end portion on the side of the liquid crystal display206in a space between the battery box203and the shutter drive section205bwhere the first image blur correction device130is provided. The base131is fixed to the first housing201. The first housing201and the base131support the imaging element holding member132to be movable in the direction X and the direction Y.

For example, a configuration can be made in which the imaging element holding member132is sandwiched in the direction Z by two fixing members (not shown) fixed to the first housing201, and balls (not shown) are disposed between the two fixing members and the imaging element holding member132. With this, the imaging element holding member132can be supported to be movable in the direction X and the direction Y.

In such a configuration, for example, a guide hole (not shown) that is opened on the side of the imaging element holding member132is provided in at least one of the two fixing members. A pin (not shown) that is inserted into the guide hole is provided in the imaging element holding member132. With this, the imaging element holding member132is movable in the direction X and the direction Y in a range in which the pin of the imaging element holding member132moves inside the guide hole of the fixing member.

The first yoke Y1and the second yoke Y2are members for suppressing magnetic flux leakage of the first magnet M1. The first yoke Y1is a rectangular flat plate-shaped member in which a thickness direction is parallel to the direction Z, and is fixed to the base131. The second yoke Y2is a rectangular flat plate-shaped member in which a thickness direction is parallel to the direction Z, and is fixed to the first housing201by a fixing member (not shown) to face the first yoke Y1.

The first magnet M1is a permanent magnet and is fixed to a surface of the second yoke Y2on a side facing the first yoke Y1. With this, the first magnet M1is fixed to the first housing201. The first magnet M1is provided such that a direction connecting an N-pole and an S-pole (both magnetic poles) is the direction X. That is, the first magnet M1is provided such that the N-pole and the S-pole are opposite sides in the direction X. In an example ofFIG.3, although the first magnet M1is provided such that, in the X direction, the N-pole is on the side of the imaging element120and the S-pole is on the side of the battery box203, the first magnet M1may be provided with the positions of the N-pole and the S-pole replaced.

The first coil C1is formed by winding an electric wire to which electric conduction is provided with a current output from the first FPC133. The first coil C1is fixed to the imaging element holding member132to face the first magnet M1between the first yoke Y1and the second yoke Y2. The first coil C1is fixed at a position in the imaging element holding member132different from the imaging element120in the direction X. The first coil C1is provided such that a central axis of winding is directed in the direction Y.

As described above, the imaging element holding member132is supported by the base131to be movable in the direction X and the direction Y. The imaging element holding member132supports the imaging element120at a position where an image is formed in the imaging element120by the lens device110attached to the first mount202.

In the first image blur correction device130, in a situation in which image blur does not occur in the imaging device100, the position of the imaging element holding member132is controlled such that the optical axis111of the lens device110coincides with a center of the imaging element120in an XY plane. The position of the imaging element holding member132in this case is referred to as a reference position of the imaging element holding member132.

In addition to the imaging element120, the first coil C1, the first FPC133, and the first hall element H1are fixed to the imaging element holding member132. As in the example ofFIG.2, a cover glass134that transmits light incident from the lens device110attached to the first mount202onto the imaging element120may be provided in the imaging element120.

The first FPC133is provided in an end portion of the first coil C1on a side opposite to an end portion facing the first magnet M1. Alternatively, the first FPC133may be provided in the imaging element holding member132. The first FPC133makes a current flow in the first coil C1under the control of the first main board204. With this, magnetic force in the direction X can be generated with respect to the first coil C1by magnetic force from the first magnet M1, and the imaging element holding member132can be moved in the direction X.

The first coil C1, the first magnet M1, the first yoke Y1, the second yoke Y2, and the first FPC133configure a voice coil motor XVCM that drives the imaging element holding member132in the direction X.

The first hall element H1is fixed to a surface of the first FPC133on the side of the first magnet M1. In the example ofFIG.2, the first hall element H1is fixed at a position that is a hollow portion of the first coil C1, in the surface of the first FPC133. The first hall element H1detects a magnetic field from the first magnet M1and outputs a detection result of the magnetic field to the first FPC133in a form of an electric signal.

The first FPC133outputs the detection result of the magnetic field output from the first hall element H1, to the first main board204. The first main board204detects a position of the imaging element holding member132in the direction X based on the detection result output from the first FPC133. Then, the first main board204controls the position of the imaging element holding member132in the direction X by controlling the current flowing in the first coil C1based on a detection result of the position in the direction X.

As shown inFIG.2, the first image blur correction device130is provided between the battery box203and the shutter drive section205beach haying a large volume in the direction X. For this reason, the size of the first image blur correction device130in the direction X is significantly restricted. In the first image blur correction device130, the first coil C1is disposed in parallel with the imaging element120in the direction X, that is, in the longitudinal direction of the imaging element120. Thus, the size of the first coil C1in the direction X is significantly restricted.

In the first image blur correction device130, the shapes and the sizes of the base131, the imaging element holding member132, the cover glass134, and the like are not limited to those shown in the drawings, and can be any shapes or sizes.

In the first image blur correction device130, the direction X configures a first direction, the direction Y configures a second direction, the imaging element holding member132configures a movable mechanism, the first housing201and the base131configure a support mechanism, the voice coil motor XVCM configures a first drive portion, the first magnet M1configures a first magnetic force generator, the first coil C1configures a first coil, and the first hall element H1configures a magnetic field detection element.

FIG.3is a schematic planar sectional view as the imaging element120, the first image blur correction device130, and the battery box203ofFIG.2are viewed in the direction Y from above.

FIG.4is a schematic front view as the imaging element120and the first image blur correction device130ofFIG.2are viewed in the direction Z from the side of the lens device110, inFIG.4, the base131, the first yoke Y1, the second yoke Y2, and the cover glass134are omitted.

A first magnet center M1aindicates the center between the N-pole and the S-pole (both magnetic poles) in the first magnet M1. The center between the N-pole and the S-pole is a plane including a middle point of each line of magnetic force between the N-pole and the S-pole.

A first coil central axis C1a.is the central axis of winding of the first coil C1. That is, the first coil C1is configured by winding an electric wire around the first coil central axis C1a.

In the example ofFIGS.3and4, the imaging element holding member132is a state of being at the above-described reference position. In this state, the first coil central axis C1adeviates to the side of the imaging element120with respect to the first magnet center M1ain the direction X. With this, the first coil C1can be made large to the inside (the side of the imaging element120) of the first image blur correction device130without being made large to the outside (the side of the battery box203) of the first image blur correction device130, compared to a configuration of the related art in which the first coil central axis C1adoes not deviate with respect to the first magnet center M1ain the direction X.

Accordingly, it is possible to increase a winding number of the first coil C1while suppressing an increase in size of the first image blur correction device130and to increase the thrust of the voice coil motor XVCM. There is a decrease in thrust due to deviation of the first coil central axis C1a.with respect to the first magnet center M1a.However, an amount of the decrease in thrust is smaller than an amount of increase in thrust due to an increase in the winding number of the first coil C1. For this reason, as described below referring toFIG.5, it is possible to increase the thrust of the voice coil motor XVCM as a whole.

In other words, in the embodiment, a slight decrease in thrust due to deviation of the first magnet center M1aand the first coil central axis C1afrom each other is allowed, and the first coil C1is increased in size toward the inside. In this manner, it is possible to considerably increase thrust with an increase in size of the first coil C1while suppressing an increase in size of the first image blur correction device130due to an increase in size of the first coil C1toward the outside, to improve thrust as a whole.

The first hall element H1is provided at a position coinciding with the first magnet center M1athat is the center between the N-pole and the S-pole of the first magnet M1, in the direction X. With this, it is possible to improve linearity of position detection using the first hall element H1. The linearity of the position detection makes a radio of change in detection output of the first hall element H1to change in position of the imaging element holding member132constant.

As shown inFIG.4, the first image blur correction device130may comprise a voice coil motor YVCM including a second magnet M2and a second coil C2, in addition to the voice coil motor XVCM. The voice coil motor YVCM is configured with the second coil C2, the second magnet M2, a third yoke (not shown), and a fourth yoke (not shown).

The third yoke and the fourth yoke are members for suppressing magnetic flux leakage of the second magnet M2. The third yoke is a rectangular flat plate-shaped member in which a thickness direction is parallel to the direction Z, and is fixed to the base131. The fourth yoke is a rectangular flat plate-shaped member in which a thickness direction is parallel to the direction Z, and is fixed to the first housing201by a fixing member (not shown) to face the third yoke.

The second magnet M2is a rectangular parallelepiped permanent magnet in which a thickness direction is parallel to the direction Z, and is fixed to a surface of the fourth yoke on a side facing the third yoke. The second magnet M2is provided such that a direction connecting the N-pole and the S-pole is directed in the direction Y.

The second coil C2is formed by winding an electric wire to which electric conduction is provided with a current output from a second FPC (not shown). The second coil C2is fixed to the imaging element holding member132to face the second magnet M2between the third yoke and the fourth yoke. The second coil C2is provided such that a central axis of winding is directed in the direction Z.

In addition to the imaging element120, the first coil C1, the first FPC133, and the first hall element H1described above, the second coil C2, the second FPC (not shown), and a second hall element H2are fixed to the imaging element holding member132.

The second FPC is provided in an end portion of the second coil C2on a side opposite to an end portion facing the second magnet M2. Alternatively, the second FPC may be provided in the imaging element holding member132. The second FPC makes a current flow in the second coil C2under the control of the first main board204. With this, magnetic force in the direction Y can be generated with respect to the second coil C2by magnetic force from the second magnet M2, and the imaging element holding member132can be moved in the direction Y.

The second hall element H2is fixed to a surface of the second FPC on the side of the second magnet M2.1nthe example ofFIG.4, the second hall element H2is fixed at a position that is a hollow portion of the second coil C2, in the surface of the second FPC. The second hall element H2detects a magnetic field from the second magnet M2and outputs a detection result of the magnetic field to the second FPC.

The second FPC outputs the detection result of the magnetic field output from the second hall element H2, to the first main board204. The first main board204detects a position of the imaging element holding member132in the direction Y based on the detection result output from the second FPC. Then, the first main board204controls the position of the imaging element holding member132in the direction Y by controlling the current flowing in the second coil C2based on a detection result of the position in the direction Y.

A second magnet center M2aindicates the center between the N-pole and the S-pole (both magnetic poles) in the second magnet M2.

A second coil central axis C2ais a central axis of winding of the second coil C2. That is, the second coil C2is configured by winding an electric wire around the second coil central axis C2a.

in a state in which the imaging element holding member132is at the above-described reference position, the second coil central axis C2adeviates to the side of the imaging element120with respect to the second magnet center M2ain the direction Y. With this, the second coil C2can be made large to the inside (the side of the imaging element120) of the first image blur correction device130without being made large to the outside (lower side) of the first image blur correction device130, compared to a configuration of the related art in which the second coil central axis C2a,does not deviate with respect to the second magnet center M2a,in the direction Y.

Accordingly, it is possible to increase a winding number of the second coil C2and to increase the thrust of the voice coil motor YVCM while suppressing an increase in size of the first image blur correction device130. There is a decrease in thrust due to deviation of the second coil central axis C2awith respect to the second magnet center M2a.However, an amount of the decrease in thrust is smaller than an amount of increase in thrust due to an increase in the winding number of the second coil C2. For this reason, it is possible to increase the thrust of the voice coil motor YVCM as a whole.

InFIG.4, the voice coil motor YVCM configures a second drive portion, the second magnet M2configures a second magnetic force generator, and the second coil C2configures a second coil.

Effects of Image Blur Correction Device of First Embodiment

In the first image blur correction device130configured as described above, the first coil central axis C1adeviates to the side of the imaging element120with respect to the first magnet center M1ain the direction X. In this manner, it is possible to increase the thrust of the voice coil motor XVCM while suppressing an increase in size of the first image blur correction device130. The second coil central axis C2adeviates to the side of the imaging element120with respect to the second magnet center M2ain the direction Y, whereby it is possible to increase the thrust of the voice coil motor YVCM while suppressing an increase in size of the first image blur correction device130.

Note that, for example, in a case where the size in the direction Y is not strictly restricted, a case where requested thrust of the voice coil motor YVCM is not large, or the like, a configuration may be made that the second coil central axis C2adoes not deviate with respect to the second magnet center M2ain the direction Y.

FIG.5is a graph showing an example of improvement of thrust by the first image blur correction device130ofFIG.1. The horizontal axis ofFIG.5indicates the position of the imaging element holding member132in the direction X in terms of a distance [mm] from the above-described reference position. A control range R1is a possible range of the position of the imaging element holding member132in control for image blur correction of the first image blur correction device130. The vertical axis ofFIG.5indicates thrust [N] for moving the imaging element holding member132in the direction X that is obtained by the voice coil motor XVCM.

A first position thrust characteristic501shows a relationship between the position of the imaging element holding member132and the thrust of the voice coil motor XVCM in the configuration of the related art for reference. The configuration of the related art is a configuration in which, when the imaging element holding member132is at the reference position, the first coil central axis C1adoes not deviate with respect to the first magnet center M1ain the direction X. A position of an end portion in the first coil C1on the side of the battery box203in the configuration of the related art is identical to a position of an end portion in the first coil C1of the embodiment on the side of the battery box203.

As shown in the first position thrust characteristic501, in the configuration of the related art, the thrust of the voice coil motor XVCM is the highest when the distance from the reference position of the imaging element holding member132is 0 [mm], that is, the imaging element holding member132is at the reference position.

A second position thrust characteristic502shows a relationship between the position of the imaging element holding member132and the thrust of the voice coil motor XVCM in the embodiment. As shown in the second position thrust characteristic502, in the embodiment, the thrust of the voice coil motor XVCM is the highest when the imaging element holding member132deviates to the side of the battery box203from the reference position. Then, as shown in the second position thrust characteristic502, the average thrust of the voice coil motor XVCM is improved compared to the example of the first position thrust characteristic501.

As shown inFIG.5, in the embodiment, there is a decrease in thrust due to deviation of the first coil central axis C1awith respect to the first magnet center M1a.However, an amount of the decrease in thrust is smaller than an amount of increase in thrust due to an increase in the winding number of the first coil C1. For this reason, it is possible to increase the thrust of the voice coil motor XVCM as a whole.

Although an increase in thrust of the voice coil motor XVCM has been described, the same applies to an increase in thrust of the voice coil motor YVCM.

First Modification Example of Image Blur Correction Device of First Embodiment

FIG.6is a diagram showing a first modification example of the first image blur correction device130ofFIG.1and is a diagram corresponding toFIG.3. InFIG.6, the same components as shown inFIGS.1to4are represented by the same reference numerals.

A movable body end portion position E1is a position in the direction X of an end portion in a movable body consisting of the imaging element holding member132and a member fixed to the imaging element holding member132on a side in a direction from the first coil central axis C1a,toward the first magnet center M1ain the direction X. That is, the movable body end portion position E1is the position in the direction X of the end portion in the above-described movable body on the side of the battery box203.

In the example ofFIG.6, the member fixed to the imaging element holding member132is the imaging element120, the first coil C1, the first hall element H1, the first FPC133, and the cover glass134, and among these members, the first coil C1is provided closest to the side of the battery box203. Accordingly, the movable body end portion position E1is the position in the direction X of the end portion in the first coil C1on the side of the battery box203.

A movable region end portion position E2is a position in the direction X of an end portion in a region through which the movable body consisting of the imaging element holding member132and the member fixed to the imaging element holding member132is capable of passing, on the side of the battery box203. That is, the movable region end portion position E2is the position in the direction X of the end portion in a range through which the above-described movable body end portion position E1can move with the drive of the voice coil motor XVCM, on the side of the battery box203. The region through which the movable body consisting of the imaging element holding member132and the member fixed to the imaging element holding member132passes is required to be secured as a space for the first image blur correction device130inside the first housing201such that the movable body does not interfere with other components.

Positions in the direction X of end portions of the base131, the first yoke Y1, and the second yoke Y2on the side of the battery box203in the direction X coincide with the movable region end portion position E2.

The first image blur correction device130of the first modification example shown inFIG.6has the same configuration as inFIG.3, excluding that a width in the direction X of the first magnet M1is made large to the side of the battery box203.

The first magnet M1ofFIG.6has the width in the direction X is made large to the side of the battery box203such that the position in the direction X of the end portion on the side of the battery box203coincides with the movable region end portion position E2, compared to the example ofFIG.3. As a result, the first magnet center M1aofFIG.6deviates to the side of the battery box203with respect to the first coil central axis C1acompared to the example ofFIG.3. With this, it is possible to make the first magnet M1large to the side of the battery box203without enlarging a space for the first image blur correction device130inside the first housing201, compared to the configuration ofFIG.3in which the first magnet M1is not provided to the movable region end portion position E2in the direction X.

Accordingly, it is possible to increase the magnetic force of the first magnet M1and to increase the thrust of the voice coil motor XVCM while suppressing an increase in size of the first image blur correction device130. There is a decrease in thrust due to deviation of the first magnet center M1awith respect to the first coil central axis C1a.However, an amount of the decrease in thrust is smaller than an amount of increase in thrust due to an increase in magnetic force of the first magnet M1. For this reason, it is possible to increase the thrust of the voice coil motor XVCM as a whole.

With the first image blur correction device130of the first modification example, the first magnet111is provided to the movable region end portion position E2, whereby it is possible to make the first magnet M1large such that the space for the first image blur correction device130inside the first housing201is not enlarged. For this reason, it is possible to increase the magnetic force of the first magnet M1and to increase the thrust of the voice coil motor XVCM while suppressing an increase in size of the first image blur correction device130.

Though not shown, the second magnet M2may be provided to a position in the direction Y of an end portion in a region through which the movable body consisting of the imaging element holding member132and the member fixed to the imaging element holding member132passes, on a lower side. With this, it is possible to make the second magnet M2large such that the space for the first image blur correction device130inside the first housing201is not enlarged. For this reason, it is possible to increase the magnetic force of the second magnet M2and to increase the thrust of the voice coil motor YVCM while suppressing an increase in size of the first image blur correction device130.

Second Modification Example of Image Blur Correction Device of First Embodiment

FIG.7is a diagram showing a second modification example of the first image blur correction device130ofFIG.1and is a diagram corresponding toFIG.3. InFIG.7, the same components as those inFIGS.1to4are represented by the same reference numerals. The first image blur correction device130of the second modification example shown inFIG.7has the same configuration as inFIG.3, excluding that the positions of the first magnet M1, the first coil C1, and the first hall element H1are replaced.

In the first image blur correction device130of the second modification example, the first magnet M1is fixed at a position in the imaging element holding member132different from the imaging element120in the direction X. The first coil C1is fixed to the second yoke Y2fixed to the first housing201side.

In the example ofFIG.7, the first FPC133and the first hall element H1are also provided on the side of the second yoke Y2along with the first coil C1.

Even in this example, the first coil C1, the first magnet M1, the first yoke Y1, the second yoke Y2, and the first FPC133configure the voice coil motor XVCM that drives the imaging element holding member132in the direction X.

In the example ofFIG.7, in a state in which the imaging element holding member132is at the reference position, the first magnet center M1ais positioned on the side of the imaging element120more than the first coil central axis C1ain the direction X.

With this, the first magnet M1can be made large to the inside (the side of the imaging element120) of the first image blur correction device130without being made large to the outside (the side of the battery box203) of the first image blur correction device130, compared to the configuration of the related art in which the first magnet center M1adoes not deviate with respect to the first coil central axis C1ain the direction X. With this, it is possible to increase the magnetic force of the first magnet M1and to increase the thrust of the voice coil motor XVCM while suppressing an increase in size of the first image blur correction device130.

Similarly, the voice coil motor YVCM may also have a configuration in which the positions of the second magnet M2, the second coil C2, the second FPC (not shown), and the second hail element H2are replaced in the example shown inFIG.4.

Third Modification Example of Image Blur Correction Device of First Embodiment

FIG.8is a diagram showing a third modification example of the first image blur correction device130ofFIG.1and is a diagram corresponding toFIG.3. InFIG.8, the same components as those inFIGS.1to4are represented by the same reference numerals. The first image blur correction device130of the third modification example shown inFIG.8has the same configuration as inFIG.3, excluding that the first hall element H1is provided at a position coinciding with the first coil central axis C1ain the direction X.

The first hall element141is provided at the position coinciding with the first coil central axis C1ain the direction X, whereby it is possible to reduce the influence of noise received from the first coil C1on the first hall element H1. With this, it is possible to improve the accuracy of detection of the magnetic field from the first magnet M1by the first hall element H1.

Though not shown, a configuration may be made in which the second hall element H2is provided at a position coinciding with the second coil central axis C2ain the direction V in the example shown inFIG.4. Accordingly, it is possible to reduce the influence of noise received from the second coil C2on the second hall element142. With this, it is possible to improve the accuracy of detection of the magnetic field from the second magnet M2by the second hall element H2.

Combination of Respective Modification Examples of Image Blur Correction Device of First Embodiment

The respective modification examples shown inFIGS.6to8can also be combined.

For example, in the example ofFIG.7, similarly to the example ofFIG.6, the first coil C1fixed to the side of the second yoke Y2may be provided to the position in the direction X of the end portion in the region through which the movable body consisting of the imaging element holding member132and the member fixed to the imaging element holding member132passes, on the side of the battery box203. In the example ofFIG.7, the above-described movable body end portion position E1is the position in the direction X of the end portion in the first magnet M1on the side of the battery box203.

In the example ofFIG.6or7, similarly to the example ofFIG.8, a configuration may be made in which the first hall element H1is provided at the position coinciding with the first coil central axis C1ain the direction X.

Lens Device Comprising Image Blur Correction Device of Second Embodiment

FIG.9is a schematic planar sectional view schematically showing a lens device110comprising a second image blur correction device940that is a second embodiment of an image blur correction device of the present invention. The second image blur correction device940is provided in the lens device110and performs so-called lens shift-type image blur correction to correct image blur by moving lenses included in the lens device110.

In the example ofFIG.9, the lens device110comprises a second housing910, a second mount920, a first lens931, a second lens932, a third lens933, a fourth lens934, the second image blur correction device940, and a second main board (not shown).

The second housing910has a cylindrical shape and houses components, such as the first lens931, the second lens932, the third lens933, the fourth lens934, and the second image blur correction device940.

The second mount920is provided as one opening portion of the second housing910having a cylindrical shape and is a mechanism for attaching and detaching the lens device110to the first mount202of the imaging device100ofFIG.2.

The first lens931, the second lens932, the third lens933, and the fourth lens934configure an imaging optical system of the lens device110. Among the lenses, the third lens933is an image blur correction lens. The first lens931, the second lens932, the third lens933, the fourth lens934, and the second mount920are disposed in this order along the direction Z that is the direction of the optical axis111of the imaging optical system.

The first lens931, the second lens932, and the fourth lens934are fixed to the second housing910by a first lens support mechanism911, a second lens support mechanism912, and a third lens support mechanism913fixed in the second housing910, respectively.

The second image blur correction device940comprises a correction lens holding member941, a fifth yoke Y5, a sixth yoke Y6, a third magnet M3, a third coil C3, a third FPC (not shown), a third hall element (not shown), a seventh yoke Y7, an eighth yoke Y8, a fourth magnet M4, a fourth coil C4, a fourth FPC (not shown), and a fourth hall element (not shown).

The fifth yoke Y5and the sixth yoke Y6are members for suppressing magnetic flux leakage of the third magnet M3. The fifth yoke Y5is a rectangular flat plate-shaped member in which a thickness direction is parallel to the direction Z, and is fixed to the second housing910by a fixing member (not shown). The sixth yoke Y6is a rectangular flat plate-shaped member in which a thickness direction is parallel to the direction Z, and is fixed to the second housing910by a fixing member (not shown) to face the fifth yoke Y5.

The third magnet M3is a rectangular parallelepiped permanent magnet in which a thickness direction is parallel to the direction Z, and is fixed to a surface of the sixth yoke Y6on a side facing the fifth yoke Y5. The third magnet M3is provided such that a direction connecting the N-pole and the S-pole is directed in the direction X. In the example ofFIG.9, although the third magnet M3is provided such that the N-pole is on the side of the third lens933in the direction X, the third magnet M3may be provided with the positions of the N-pole and the S-pole replaced.

The third coil C3is formed by winding an electric wire to which electric conduction is provided with a current output from the third FPC. The third coil C3is fixed to the correction lens holding member941to face the third magnet M3between the fifth yoke Y5and the sixth yoke Y6. The third coil C3is provided such that a central axis of winding is directed in the direction Z.

The correction lens holding member941is supported to be movable in the direction X and the direction Y with respect to the second housing910. The correction lens holding member941supports the third lens933.

In the second image blur correction device940, in a state in which image blur does not occur in the imaging device100the position of the correction lens holding member941is controlled such that the optical axis111of the lens device110coincides with the center of the imaging element120in the XY plane. The position of the correction lens holding member941in this case is referred to as a reference position of the correction lens holding member941.

In addition to the third lens933, the third coil C3, the third FPC, and the third hall element are fixed to the correction lens holding member941.

The third FPC is provided in an end portion in the third coil C3on a side opposite to an end portion facing the third magnet M3. Alternatively, the third FPC may be provided in the correction lens holding member941. The third FPC makes a current flow in the third coil C3under the control of the second main board. With this, magnetic force in the direction X can be generated with respect to the third coil C3by magnetic force from the third magnet M3, and the correction lens holding member941can be moved in the direction X.

The third coil C3, the third magnet M3, the fifth yoke Y5, the sixth yoke Y6, and the third FPC configure a voice coil motor XVCM1that drives the correction lens holding member941in the direction X.

The third hall element is fixed to a surface in the third FPC on the side of the third magnet M3. The third hall element is fixed at a position in the surface of the third FPC that is a hollow portion of the third coil C3. The third hall element detects a magnetic field from the third magnet M3and outputs a detection result of the magnetic field to the third FPC in a form of an electric signal.

The third FPC outputs the detection result of the magnetic field output from the third hall element, to the second main board. The second main board detects a position of the correction lens holding member941in the direction X based on the detection result output from the third FPC. Then, the second main board controls the position of the correction lens holding member941in the direction X by controlling the current flowing in the third coil C3based on a detection result of the position in the direction X.

In the example ofFIG.9, the correction lens holding member941is in a state of being at the above-described reference position. In this state, the central axis of the winding of the third coil C3deviates to the side of the third lens933with respect to the center between both magnetic poles in the third magnet M3, in the direction X.

With this, the third coil C3can be prevented from being made large to the outside (a direction away from the optical axis111) of the second image blur correction device940, and the third coil C3can be made large to the inside (the side of the third lens933) of the second image blur correction device940. Accordingly, it is possible to increase a winding number of the third coil C3and to increase the thrust of the voice coil motor XVCM1while suppressing an increase in size of the second image blur correction device940.

The seventh yoke Y7, the eighth yoke Y8, the fourth magnet M4, the fourth coil C4, the fourth FPC, and the fourth hall element have the same configurations as the fifth yoke Y5, the sixth yoke Y6, the third magnet M3, the third coil C3, the third FPC, and the third hall element, respectively. Then, the seventh yoke Y7, the eighth yoke Y8, the fourth magnet M4, the fourth coil C4, the fourth FPC, and the fourth hall element generate thrust for moving the correction lens holding member941in the direction X under the control of the second main board. In regard to the fourth magnet M4, in the example ofFIG.9, although the fourth magnet M4such that the S-pole is on the side of the third lens933in the direction X, the fourth magnet M4may be provided with the positions of the N-pole and the S-pole replaced.

The fourth coil C4, the fourth magnet M4, the seventh yoke Y7, the eighth yoke Y8, and the fourth FPC configure a voice coil motor XVCM2that drives the correction lens holding member941in the direction X. It is possible to increase thrust for moving the correction lens holding member941in the direction X by combining the voice coil motor XVCM2and the above-described voice coil motor XVCM1. Note that the lens device110may have a configuration in which the voice coil motor XVCM1or the voice coil motor XVCM2is omitted.

Although a configuration in which the control of the second image blur correction device940is performed by the second main board of the lens device110has been described, a configuration may be made in which the control of the second image blur correction device940is performed by the first main board204of the imaging device100.

In the second image blur correction device940, the shapes or the sizes of the correction lens holding member941and the like are not limited to those shown in the drawings, and can be any shapes or sizes.

The lens device110comprises a voice coil motor YVCM1that generates thrust for moving the correction lens holding member941in the Y-direction. The voice coil motor YVCM1has the same configuration as the voice coil motor YVCM described referring toFIG.4, for example.

Each configuration of the first image blur correction device130described referring toFIGS.2to8can also be applied to the second image blur correction device940ofFIG.9. In the second embodiment where the second image blur correction device940is provided in the lens device110, a configuration may be made in which the first image blur correction device130of the imaging device100is omitted and the imaging element holding member132is fixed to the first housing201.

In the second image blur correction device940, the third lens933configures an optical component, the second housing910configures a support mechanism, the correction lens holding member941configures a movable mechanism, the voice coil motor XVCM1and the voice coil motor XVCM2configure a first drive portion, the third magnet M3and the fourth magnet M4configure a first magnetic force generator, the third coil C3and the fourth coil C4configure a first coil, and the third hall element and the fourth hall element configure a magnetic field detection element.

Effects of Image Blur Correction Device of Second Embodiment

In the second image blur correction device940configured as described above, similarly to the first image blur correction device130, it is possible to increase the thrust of the voice coil motor while suppressing an increase in size of the second image blur correction device940.

For example, in the lens device110, although the voice coil motor is disposed on an outer periphery side of the third lens933as viewed in the direction Z, there is a need to make the third lens933large to improve optical performance or to improve anti-vibration performance. For this reason, the voice coil motor of the lens device110is required to be provided in a small space of an outer peripheral portion of the large third lens933and to generate large thrust to move the third lens933that is heavy due to a large size.

In contrast, the second image blur correction device940can have a small size and can generate large thrust. For this reason, it is possible to make the third lens933of the lens device110large and to achieve improvement of optical performance or anti-vibration performance of the lens device110.

In the respective embodiments described above, although the imaging device100that is a digital camera has been described, the present invention can also be applied to an imaging device mounted in various devices, such as a smartphone, a tablet terminal, and a wearable terminal.

In the embodiment, although a hall element, such as the first hall element H1, has been described as an example of a magnetic field detection element, the magnetic field detection element is not limited to the hall element. For example, the magnetic field detection element can be various magnetic sensors capable of detecting a magnetic field, such as a magneto resistive (MR) sensor or a magnetic impedance element, other than the hall element.

As described above, at least the following matters are described in the specification.

(1) An image blur correction device that corrects blur of an image formed in an imaging element by an imaging optical system, the image blur correction device including a movable mechanism to which an optical component included in the imaging element or the imaging optical system is fixed, a support mechanism that supports the movable mechanism to be movable in a first direction perpendicular to an optical axis of the imaging optical system, and a first drive portion that generates thrust of moving the movable mechanism in the first direction, in which the first drive portion includes a first magnetic force generator that is fixed to one portion of the support mechanism and the movable mechanism and in which a direction connecting both magnetic poles is parallel to the first direction, and a first coil that is fixed to the other portion of the support mechanism and the movable mechanism to face the first magnetic force generator, and in a state in which the movable mechanism is at a reference position where the optical axis of the imaging optical system coincides with a center of the imaging element, a position in the first direction of a center between both magnetic poles of the first magnetic force generator and a central axis of winding of the first coil deviate from each other.

(2) The image blur correction device described in (1), in which the first coil is fixed at a position in the movable mechanism different from the imaging element or the optical component fixed to the movable mechanism in the first direction, the first magnetic force generator is fixed to the support mechanism, and in a state in which the movable mechanism is at the reference position, the central axis of the winding of the first coil is positioned on a side of the imaging. element or the optical component fixed to the movable mechanism with respect to the center between both magnetic poles of the first magnetic force generator, in the first direction.

(3) The image blur correction device described in (2), in which a position in the first direction of an end portion in the first magnetic force generator, on a side in a direction from the central axis of the winding of the first coil toward the center between both magnetic poles of the first magnetic force generator in the first direction, coincides with a position in the first direction of an end portion in a region through which a movable body consisting of a member fixed to the movable mechanism and the movable mechanism is capable of passing, on the side in the direction from the central axis of the winding of the first coil toward the center between both magnetic poles of the first magnetic force generator in the first direction.

(4) The image blur correction device described in (1), in which the first magnetic force generator is fixed at a position movable mechanism different from the imaging element or the optical component fixed in the movable mechanism in the first direction, the first coil is fixed to the support mechanism, and in a state in which the movable mechanism is at the reference position, the center between both magnetic poles of the first magnetic force generator is positioned on the side of the imaging element or the optical component fixed to the movable mechanism from the central axis of the winding of the first coil in the first direction.

(5) The image blur correction device described in (4), in which a position in the first direction of an end portion in the first coil, on a side in a direction from the center between both magnetic poles of the first magnetic force generator toward the central axis of the winding of the first coil in the first direction, coincides with a position in the first direction of an end portion in a region through which a movable body consisting of the movable mechanism and a member fixed to the movable mechanism is capable of passing, on the side in the direction from the center between both magnetic poles of the first magnetic force generator toward the central axis of the winding of the first coil in the first direction.

(6) The image blur correction device described in any one of (1) to (5), further including a magnetic field detection element that is fixed to one portion of the support mechanism and the movable mechanism to which the first coil is fixed, and detects a position of the movable mechanism in the first direction where a magnetic field from the first magnetic force generator is detected, in which the magnetic field detection element is configured such that a position in the first direction coincides with the center between both magnetic poles of the first magnetic force generator in a state in which the movable mechanism is at the reference position.

(7) The image blur correction device described in any one of (1) to (5), further including a magnetic field detection element that is fixed to one portion of the support mechanism and the movable mechanism to which the first coil is fixed, and detects a position of the movable mechanism in the first direction where a magnetic field from the first magnetic force generator is detected, in which the magnetic field detection element is configured such that a position in the first direction coincides with the central axis of the winding of the first coil in a state in which the movable mechanism is at the reference position.

(8) The image blur correction device described in any one of (1) to (7), in which the imaging element is fixed to the movable mechanism, and the first direction is parallel to a longitudinal direction of the imaging element.

(9) The image blur correction device described in any one of (1) to (8), in which the support mechanism supports the movable mechanism to be movable in the first direction and a second direction perpendicular to the optical axis of the imaging optical system and the first direction, the image blur correction device further includes a second drive portion that generates thrust of moving the movable mechanism in the second direction, the second drive portion includes a second magnetic force generator that is fixed to one portion of the support mechanism and the movable mechanism and in which a direction connecting bath magnetic poles is parallel to the second direction, and a second coil that is fixed to the other portion of the support mechanism and the movable mechanism to face the second magnetic force generator, and in a state in which the movable mechanism is at the reference position, a position of a center between both magnetic poles of the second magnetic force generator in the second direction coincides with a central axis of winding of the second coil.

(10) An imaging device including the image blur correction device described in any one of (1) to (9), in which the imaging element is fixed to the movable mechanism.

(11) A lens device including the image blur correction device described in any one of (1) to (9), in which the optical component is fixed to the movable mechanism.

The present invention is highly convenient and effective in a case of being applied to a digital camera, such as a single lens reflex camera or a mirrorless camera, an in-vehicle camera, a surveillance camera, or a smartphone.

EXPLANATION OF REFERENCES

100: imaging device110: lens device111: optical axis120: imaging element130: first image blur correction device131: base132: imaging element holding member133: first FPC134: cover glassY1: first yokeY2: second yokeC1: first coilM1: first magnetH1: first hall element201: first housing202: first mount203: battery box204: first main board205: shutter unit205a:shutter section205b:shutter drive section206: liquid crystal displayM1a:first magnet centerC1a:first coil central axisC2: second coilM2: second magnet142: second hall elementM2a:second magnet centerC2a:second coil central axis501: first position thrust characteristic502: second position thrust characteristicR1: control rangeE1: movable body end portion positionE2: movable region end portion position910: second housing911: first lens support mechanism913: third lens support mechanism920: second mount931: first lens932: second lens933: third lens934: fourth lens940: second image blur correction device941: correction lens holding memberY5: fifth yokeY6: sixth yokeY7: seventh yokeY8: eighth yokeC3: third coilC4: fourth coilM3: third magnetM4: fourth magnet