JP2020170963A - Blur correction device and electronic apparatus - Google Patents

Abstract

To provide a blur correction device for correcting camera shake, and the like capable of reducing the effect of the magnetic field on the image pickup device while reducing the size.SOLUTION: A blur correction device has a movable member that holds an image pickup device and is movable in a direction orthogonal to the optical axis of an imaging optical system. The movable member has a coil 53c arranged therein, and a permanent magnet is arranged opposite the coil, and further, a conductive member is placed on the outer circumference of the coil. With this, the movable member is moved by the coil and the permanent magnet.SELECTED DRAWING: Figure 6

Description

The present invention relates to a blur correction device and an electronic device, and more particularly to a blur correction device that corrects camera shake during shooting.

Generally, as one of the electronic devices, an imaging device including a blur correction device that corrects camera shake during shooting is known. The blur correction performed by the blur correction device includes a method of driving the optical lens in a direction orthogonal to the optical axis and a method of driving the image sensor in a direction orthogonal to the optical axis. For example, there is an image pickup device that drives an image pickup device by a voice coil motor including a magnet and a coil to correct blurring (Patent Document 1).

By the way, in a voice coil motor, it is known that an electromagnetic wave is generated from the coil and the electromagnetic wave affects the image pickup apparatus. Therefore, as a general measure, a structure that magnetically isolates the coil that is a noise source from other parts is used, or a shield member is used.

For example, the photographing lens is provided with a blur correction mechanism including a voice coil motor, and a shield member made of a magnetic material is arranged to shield an electromagnetic wave (magnetic field) generated from the coil (Patent Document 2).

Japanese Unexamined Patent Publication No. 2010-15107 JP-A-2017-173757

However, when the coil is arranged near the image sensor as in the image pickup device described in Patent Document 1, the magnetic field generated by the coil reaches the image sensor and adversely affects the image as magnetic noise. Furthermore, as the sensitivity of the image sensor increases, in addition to the coil that is the noise source, a weak magnetic field from the solder joint of the coil terminal and the wiring pattern to which the coil is connected also adversely affects the image as magnetic noise. I will give it.

On the other hand, since the distance between the image sensor and the coil is narrow, it is difficult to arrange the shield member between the image sensor and the coil as described in Patent Document 2.

Therefore, an object of the present invention is to provide a blur correction device and an electronic device capable of reducing the influence of a magnetic field on an image sensor while achieving miniaturization.

In order to achieve the above object, the blur correction device according to the present invention is used in an electronic device including an image pickup device that outputs an image signal corresponding to an optical image imaged via an image pickup optical system, and the image pickup element is used as described above. A blur correction device that corrects blurring that occurs in an image indicated by the image signal by moving it in a direction orthogonal to the optical axis of the image pickup optical system, holding the image sensor and moving in a direction orthogonal to the optical axis. It has a possible movable member, a coil arranged on the movable member and supplied with power, and a permanent magnet arranged so as to face the coil, and the movable member is moved by the coil and the permanent magnet. It is characterized in that a conductive member is arranged on the outer periphery of the coil.

According to the present invention, it is possible to reduce the influence of the magnetic field on the image sensor while achieving miniaturization.

It is a figure which shows an example of the image pickup apparatus provided with the blur correction apparatus according to 1st Embodiment of this invention. It is a figure for demonstrating the blur correction part shown in FIG. 1 (the 1). It is a figure for demonstrating the blur correction part shown in FIG. 1 (the 2). It is a figure for demonstrating the structure of the movable part shown in FIG. 2 and FIG. In the cross-sectional view shown in FIG. 3B, it is an enlarged view showing a main part for explaining a magnetic field of a coil. It is a figure for demonstrating the reduction of the magnetic field by the shield member provided in the blur correction part shown in FIG. It is a figure which shows the model of the electromagnetic field simulation. It is a figure which shows the simulation result which concerns on the magnetic field which reaches the observation surface corresponding to the position of the image pickup element when the shape of a shield member is changed. It is a perspective view which shows the movable frame, the shield member, and the coil in the blur correction part used in the camera by 2nd Embodiment of this invention. It is a figure for demonstrating the example which used the backing member as a shield member in the blur correction part which concerns on 2nd Embodiment of this invention.

Hereinafter, an example of an imaging device including a blur correction device according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing an example of an imaging device including a blur correction device according to the first embodiment of the present invention. FIG. 1A is a diagram showing the image pickup apparatus in a broken state, and FIG. 1B is a diagram showing a control system of the image pickup apparatus.

The illustrated imaging device, for example, is a digital camera (hereinafter, simply referred to as a camera), and includes a camera body 1 and a photographing lens unit (hereinafter, simply referred to as a photographing lens) 2. Then, the photographing lens 2 is attached to the camera body 1.

The photographing lens 2 includes a photographing optical system 3 composed of a plurality of lenses that capture a subject image (optical image), a lens system control 12 that controls the photographing lens 2, and a lens driving unit 13 that drives the imaging optical system 3. It is equipped. The camera body 1 is provided with an image pickup element 6 for forming an optical image through the photographing lens 2. Further, the camera body 1 is provided with a rear display device 9a, an EVF 9b, a blur correction unit 14, a blur detection unit 15, a shutter mechanism 16, and a shutter drive unit 17. In addition, the camera body 1 is provided with a camera system control unit 5, an image processing unit 7, a memory 8, and an operation detection unit 10, and the rear display devices 9a and EVF9b shown in FIG. 1A are shown in FIG. 1B. ), It is collectively indicated as the display unit 9.

The camera system control unit 5 communicates with the lens system control unit 12 via the electrical contact 11, and power is further supplied from the camera body 1 to the photographing lens 2 via the electrical contact 11.

The lens driving unit 13 drives a focal lens, an aperture, and the like provided in the imaging optical system 3 under the control of the lens system control unit 12. The blur detection unit 15 detects rotational blur of the camera including rotation around the optical axis 4. For example, a vibration gyro is used for the blur detection unit 15. The blur correction unit 14 translates the image sensor 6 in a plane orthogonal to the optical axis 4 and rotates it around the optical axis 4 to correct the blur as described later.

Under the control of the camera system control unit 5, the shutter drive unit 17 drives the shutter mechanism 16 to drive the shutter curtain to expose the image sensor 6. An optical image is formed on the image pickup device 6 via the image pickup optical system 3, and the image pickup element 6 outputs an image signal corresponding to the optical image by photoelectric conversion.

The image processing unit 7 is provided with, for example, an A / D converter, a white balance adjustment circuit, a gamma correction circuit, and an interpolation calculation circuit. The image processing unit 7 performs predetermined image processing on the image signal output from the image sensor 6 to generate image data for recording. The image processing unit 7 is provided with a color interpolation processing unit, and the color interpolation processing unit performs color interpolation (demosaiking) processing on the image signals of the Bayer array to generate color image data. Further, the image processing unit 7 compresses an image (still image), a moving image, a sound, or the like by using a predetermined method.

The focus evaluation amount and the exposure amount can be obtained from the image data output from the image processing unit 7. The camera system control unit 5 drives and controls the photographing optical system 3 by the lens system control unit 12 according to the focus evaluation amount and the exposure amount. As a result, an optical image having an appropriate amount of light is formed on the image sensor 6.

The camera system control unit 5 controls the image processing unit 7 to record image data in the memory 8. Further, the camera system control unit 5 displays an image corresponding to the image data on the display unit 9.

The camera system control unit 5 outputs a timing signal or the like at the time of imaging. Further, the camera system control unit 5 controls the camera according to the user operation. For example, when the operation detection unit 10 detects that the shutter release button (not shown) is pressed, the camera system control unit 5 drives the image sensor 6 and controls the image processing unit 7 to perform compression processing and the like.

Further, the camera system control unit 5 displays information related to shooting or the like on the display unit 9. The rear display device 9a is provided with a touch panel, and the touch panel is connected to the operation detection unit 10. The camera system control unit 5 controls the blur correction unit 14 based on the detection result obtained by the blur detection unit 15.

2 and 3 are diagrams for explaining the blur correction unit shown in FIG. 2 (a) is a perspective view showing the configuration of the blur correction unit, and FIG. 2 (b) is a perspective view showing the configuration of the blur correction unit in an exploded manner. Further, FIG. 3A is a view of the blur correction unit viewed from above, and FIG. 3B is a cross-sectional view taken along the line AA shown in FIG. 3A. In the coordinate system shown in FIGS. 2 and 3, the photographing lens 2 is located in the positive direction of the Z axis.

In FIG. 2, the Z-axis direction is a direction parallel to the optical axis 4. The blur correction unit 14 has a movable portion (movable member) 50, an upper surface fixing portion (fixing member) 60, and a lower surface fixing portion (fixing member) 70. Then, the image sensor 6 is mounted on the movable portion 50.

As will be described later, the movable portion 50 can move in a direction orthogonal to the optical axis of the imaging optical system. The movable portion 50 includes a movable frame 51, coils 53a to 53c, magnetic sensors 54a to 54c, and shield members 56a to 56c, and an FPC (flexible printed circuit board) 55 is connected to the movable portion 50.

The upper surface fixing portion 60 is provided with an upper surface yoke 61 and permanent magnets 62a to 62f. The lower surface fixing portion 70 has a base plate (support member) 71, and the base plate 71 is defined with ball rolling surfaces 72a to 72c. Further, the lower surface fixing portion 70 is provided with main spacers 73a to 73c, subspacers 74a and 74b, and a lower surface yoke 75. Permanent magnets 76a to 76f are arranged on the lower surface yoke 75, and rolling balls 77a to 77c are located on the ball rolling surfaces 72a to 72c, respectively.

In the illustrated example, the upper surface yoke 61 and the magnets 62a to 62f and the lower surface yoke 75 and the magnets 76a to form a magnetic circuit to form a so-called closed magnetic path. The magnets 62a to 62f are adhesively fixed to the upper surface yoke 61 in a state of being attracted to the magnets 62a to 62f. Similarly, the magnets 76a to 76f are adhesively fixed to the lower surface yoke 75 in a state of being attracted to the magnets 76a to 76f. Each of these magnets is magnetized in the direction of the optical axis 4. The magnets 62a and 62b, the magnets 62c and 62d, and the magnets 62e and 62f, which are adjacent magnets, are magnetized in different directions. Similarly, the magnets 76a and 76b, the magnets 76c and 76d, and the magnets 76e and 76f are magnetized in different directions.

In FIG. 3B, the magnet 62e, the magnet 62f, the magnet 76e, and S and N shown in the magnet 76f represent the magnetizing direction. That is, the magnetizing directions of the adjacent magnets 62e and 62f are different from each other, and similarly, the magnetizing directions of the adjacent magnets 76e and 76f are different from each other.

Magnets 62a and 76a, magnets 62b and 76b, magnets 62c and 76c, magnets 62d and 76d, magnets 62e and 76e, and magnets 62f and 76f, which are magnets arranged at opposite positions, are magnetized in the same direction. Magnet.

In FIG. 3B, the magnetizing directions of the magnets 62e and the magnets 76e arranged at opposite positions are the same, and similarly, the magnetizing directions of the magnets 62f and the magnets 76f arranged at the opposite positions are the same. It has the same orientation.

By defining the magnetizing direction of the magnet in this way, a strong magnetic flux density is generated in the direction of the optical axis 4 between the upper surface yoke 61 and the lower surface yoke 75.

Main spacers 73a to 73c and sub spacers 74a and 74b are arranged between the upper surface yoke 61 and the lower surface yoke 75, and the upper surface yoke 61 and the lower surface yoke 75 are kept at a predetermined interval. The movable portion 50 is arranged with a gap between the upper surface yoke 61 and the lower surface yoke 75. Rubber is provided on the side surface of the cylinder of each of the main spacers 73a to 73c, whereby a mechanical end (so-called stopper) of the movable portion 50 is formed.

A hole is formed in the base plate 71 so as to avoid the magnets 76a to 76f, and the surface of the magnet projects from this hole. Then, the base plate 71 and the lower surface yoke 75 are fixed by screws (not shown), and magnets 76a to 76f having a thickness direction larger than that of the base plate 71 are fixed so as to protrude from the base plate 71. ..

Each of the above-mentioned elements is fixed to the movable frame 51 to form the movable portion 50. The movable frame 51 is formed of a resin material, and the movable frame 51 is equipped with an image sensor 6, an FPC 55, and shield members (conductive members) 56a to 56c. Further, the coils 53a to 53c are mounted on the surface of the mounting member FPC55 on the lower surface fixing portion 70 side (Z-axis negative direction), and the electric power required for driving is supplied from the FPC55 to the coils 53a to 53c.

The FPC 55 is connected to the outside via a connector (not shown). Each of the coils 53a to 53c has an axial direction (axial center direction) of the hollow portion defined by the windings substantially parallel to the optical axis 4, and is further arranged substantially in the same plane as the image sensor 6. There is. Further, in the coils 53a to 53c, magnetic sensors 54a to 54c are arranged in the hollow portion of the winding, respectively. For example, in FIG. 3B, it is shown that in the coil 53c, the magnetic sensor 54c is arranged in the hollow portion of the winding.

The magnetic sensors 54a to 54c detect the position when the movable portion 50 moves on a plane substantially orthogonal to the optical axis 4 by using the above-mentioned magnetic circuit. For example, a Hall element is used for each of the magnetic sensors 54a to 54c.

The magnetic sensors 54a to 54c are also connected to the outside via a connector (not shown) mounted on the FPC 55. The movable frame 51 is arranged with shield members 56a to 56c, which are sheet-like conductors (non-magnetic conductive members) made of non-magnetic metal that orbit around the outer circumference of the coils 53a to 53c, respectively.

FIG. 4 is a diagram for explaining the configuration of the movable portion shown in FIGS. 2 and 3. 4 (a) is a perspective view showing a movable frame, a coil, and a shield member, and FIG. 4 (b) is a perspective view showing one coil and a shield member. In FIG. 4A, the outer shape of the image sensor 6 is shown by a broken line.

In FIG. 4A, the shield members 56a to 56c are arranged between the movable frame 51 and the coils 53a to 53c so as to cover the outer periphery of the coils 53a to 53c, and are fixed to the movable frame 51 by a predetermined method. ing. It is desirable that at least a part of the shield members 56a to 56c face the surface defined by the outer circumference of the coils 53a to 53c, respectively.

Here, as shown in FIG. 4B, for example, the shield member 56a has a surface facing the entire surface defined by the outer circumference of the coil 53a. In each of the shield members 56a to 56c, the thickness of the sheet-shaped conductor is about 0.2 mm, and for example, the material is aluminum.

Since the shield members 56a to 56c face each other on the entire surface defined by the outer circumference of the coils 53a to 53c, the width of the sheet-shaped conductor is the same as the thickness of the coils 53a to 53c in the winding axis direction.

Further, it is desirable that the shield members 56a to 56c are formed of a material having low permeability and high conductivity. Here, each of the shield members 56a to 56c is molded of aluminum. For example, if the shield members 56a to 56c are magnetic materials having high permeability such as the upper surface yoke 61 and the lower surface yoke 75, the magnetic flux of the magnetic circuit including the upper surface fixing portion 60 and the lower surface fixing portion 70 is disturbed. As a result, the magnetic flux may not reach the coils 53a to 53c efficiently. Further, in the case of a magnetic material, the magnetic forces of the magnets 62a to 62f and the magnets 76a to 76f may pull the shield members 56a to 56c and hinder the drive control of the movable portion 50. Therefore, it is desirable that the shield members 56a to 56c have a low permeability. The reason why a higher conductivity is desirable will be described later.

With the above configuration, when an electric current is passed through the coils 53a to 53c, a force according to Fleming's left-hand rule is generated to drive the movable portion 50. Then, feedback control is performed using the detection results of the magnetic sensors 54a to 54c. That is, if the current flowing through the coils 53a to 53c is controlled by using the detection results of the magnetic sensors 54a to 54c, the translation direction and the rotation direction around the axis parallel to the substantially optical axis 4 in the plane orthogonal to the optical axis 4 The movable portion 50 can be driven.

For example, by controlling the current of the coil 53c, the movable portion 50 moves in parallel in the direction parallel to the X axis. Further, by controlling the currents of the coils 53a and 53b, the movable portion 50 can be moved in parallel in the direction parallel to the Y axis or rotationally moved around the axis parallel to the optical axis 4.

When a current is passed through the coils 53a to 53c, the camera system control unit 5 performs so-called PWM control for controlling the duty ratio of the pulse width in the drive voltage in order to control the drive voltage. In PWM control, the duty ratio of a high-frequency AC signal is controlled to control the voltage. At this time, the coils 53a to 53c are superposed with a low-frequency DC current due to the drive voltage corresponding to the PWM control and a high-frequency AC current having a small amplitude according to the drive frequency of the PWM control.

By passing an electric current through the coils 53a to 53c in this way, a magnetic field is formed by the coils 53a to 53c. Then, the magnetic field causes magnetic noise in the image signal that is the output of the image sensor 6. In particular, the magnetic field generated by the change in the high-frequency current according to the driving frequency of the PWM control affects the image signal which is the output of the image sensor 6.

As shown in FIG. 3B, the image sensor 6 arranged on the movable frame 51 has a base material portion 6a as a base, a chip portion 6b including a light receiving portion, and a glass portion 6c. The chip portion 6b has a silicon layer, and the light receiving portion collects light via the photographing optical system 3 and performs photoelectric conversion. A circuit unit that receives the output signal of the light receiving unit is arranged inside the chip unit 6b.

The land portion provided on the chip portion 6b is connected to the wiring layer provided on the base material portion 6a by wire bonding (not shown), and the wiring layer is further connected to the substrate (not shown). .. Then, the image sensor 6 is arranged on a plane substantially the same as the plane on which the coil 53c is arranged. By arranging the coils 53a to 53c and the image sensor 6 in this way, the blur correction unit 14 can be made thinner. The image sensor 6 described with reference to FIG. 3B is not limited to the above configuration, and may have a configuration in which the received light can be output to the circuit unit as an output signal. Therefore, for example, the structure may be such that the chip portion 6b is directly connected to the substrate 6d by wire bonding or the like without having the base material portion 6a.

On the other hand, if the image sensor 6 and the coils 53a to 53c are arranged on the movable portion 50 and further positioned on substantially the same plane, the following problem occurs.

As described above, when the magnetic field of the coils 53a to 53c reaches the chip portion 6b in the image pickup device 6, the image obtained by the image pickup device 6 is adversely affected as magnetic noise. For example, there is a method in which the photographing lens 2 is provided with a blur correction unit having a coil, and the vibration isolator provided in the photographing lens is driven in a direction orthogonal to the optical axis to perform blur correction. In this case, since the distance from the coil to the image sensor is long, the influence of the magnetic field on the image sensor is small.

On the other hand, when the image sensor is moved by the blur correction unit 14 as described above, the magnetic fields of the coils 53a to 53c often affect the image sensor 6, and the adverse effect of magnetic noise increases.

Therefore, in the first embodiment, the shield members 56a to 56c are arranged to reduce the thickness of the blur correction unit 14 as described with reference to FIG. 3, and the shield members 56a to 56c are used to form the coils 53a to 53c with respect to the image sensor 6. Reduce the effects of magnetic fields. In particular, it is possible to reduce the influence of the high-frequency magnetic field caused by the change in the high-frequency current according to the driving frequency of the PWM control described above.

FIG. 5 is an enlarged view showing a main part for explaining the magnetic field of the coil in the cross-sectional view shown in FIG. 3 (b).

First, the magnetic field generated from the coil 53c will be described with reference to FIG. The solid arrow 81 indicates the magnetic field generated by the coil 53c. The magnetic field generated from the coil 53c is generated in a larger amount and denser than that indicated by the solid line arrow 81, but is schematically shown here in order to explain the effect on the image sensor 6.

The magnetic field generated from the upper surface side in the hollow portion of the coil 53c is generated as shown by the solid line arrow 81, branches and merges as shown by the broken line arrows 82a to 82e, and reaches the lower surface side in the hollow portion of the coil 53c. Since the shield member 56c is made of highly conductive aluminum, the magnetic field hardly passes through the shield member 56c due to the skin effect, and the shield member 56c is avoided as shown by the broken line arrows 82a to 82c.

The broken line arrow 82d indicates a magnetic field that passes through the gap 91 between the outer circumference of the coil 53c located closer to the image sensor 6 than the coil 53c and the shield member 56c. The broken line arrows 82a and 82b are magnetic fields that branch off from the solid line arrow 81 and merge as shown by the broken line arrow 82d passing through the gap 91.

Of these, as shown by the broken line arrow 82b, if the magnetic field reaching the chip portion 6b is strong, the image sensor 6 is adversely affected by magnetic noise. Further, as shown by the broken line arrow 82c, the magnetic field that branches off from the broken line arrow 82b and reaches the chip portion 6b while bypassing the shield member 53c also adversely affects the image pickup device 6 due to magnetic noise.

FIG. 6 is a diagram for explaining the reduction of the magnetic field by the shield member provided in the blur correction unit shown in FIG. FIG. 6A is a perspective view showing a magnetic field generated in the coil and the shield member, and FIG. 6B is a top view showing a current flowing through the coil and the shield member.

In FIG. 6A, the solid arrow 81 indicates the magnetic field of the coil 53c, and the solid arrow 83 indicates the magnetic field due to the current flowing through the shield member 56c. In FIG. 6B, the solid arrow 101 indicates the current flowing through the coil 53c, and the solid arrow 103 indicates the current flowing due to the coupling of the magnetic fields generated by the coil 53c. The magnetic fields generated by the coil 53c and the shield member 56c are densely generated in large quantities, but are schematically shown here for the purpose of explaining the influence on the image sensor 6. Similarly, the current is also schematically shown.

When a current flows through the coil 53c as shown by the solid arrow 101, a magnetic field is generated from the winding of the coil 53c as shown by the solid arrow 81. When this magnetic field reaches the shield member 56c that orbits the outer circumference of the coil 53c, a current forming a loop in the direction opposite to the current flowing through the coil 53c (arrow 101) flows as shown by the solid arrow 103.

Due to the coupling of the magnetic fields, a current in the direction opposite to that of the coil 53c flows through the shield member 56c. Therefore, the magnetic field generated from the shield member 56c (solid arrow 83) is in the opposite direction to the magnetic field generated from the coil 53c (solid arrow 81). Therefore, a magnetic field is generated in the shield member 56c in a direction that cancels the magnetic field of the coil 53c, and the magnetic field reaching the image sensor 6 can be reduced.

The magnetic field (canceling magnetic field) of the shield member 56c is generated when a current (solid arrow 103) flows through the shield member 56c. Since the current 103 flowing through the shield member 56c and the canceling magnetic field are in a proportional relationship, as the current (solid arrow) 103 increases, the canceling magnetic field also increases. Therefore, it is desirable that the shield member 56c is a member having high conductivity.

In FIGS. 5 and 6, the generation of a magnetic field when a current flows in one direction of the coil 53c has been described, but in actual driving, a voltage corresponding to PWM control is applied and an AC component is included. As a result, the magnetic field becomes a vector in the opposite direction, and follows the path opposite to the solid line arrow 81 shown in FIG. At this time, since the canceling magnetic field is also in the opposite direction, the same effect can be obtained by the shield member 53c.

In the above example, the relationship between the magnetic field of the coil 53c and the shield member 56c has been described, but the same effect can be obtained between the coils 53a and 53b and the shield members 56a and 56b.

In this way, in the blur correction unit 14 having the movable portion 50 in which the coils 53a to 53c and the image sensor 6 are arranged, the shield members 56a to 56c are arranged at positions that orbit the outer circumference of the coils 53a to 53c. As a result, the adverse effect of the magnetic field generated by the coils 53a to 53c on the image sensor 6 can be reduced, and the blur correction unit 14 can be miniaturized.

Although the arrangement of the shield members 56a to 56c has been described in the first embodiment, it is not necessary to include all of the shield members 56a to 56c. For example, the shield member may be arranged for a coil that is particularly close to the image sensor 6.

Further, although the shield member is a sheet-shaped conductor in the first embodiment, the shield member may be a conductor capable of passing a current that generates a canceling magnetic field that contributes to the reduction of the magnetic field of the coil. Therefore, a conductive coating may be applied to a portion located on the outer periphery of the coil provided on the movable frame 51. Even in this way, the blur correction unit can be miniaturized to reduce the adverse effect of the magnetic field on the image sensor 6.

Further, as described above, since the shield member 56 may circulate around the outer circumference of the coil, for example, a notch may be formed in a part of the shield member in order to add a lead wire for connecting the FPC 55 and the coil. It may be provided.

In addition, the shield member may be provided with a position regulating mechanism that regulates the position of the coil when assembling the blur correction unit. Alternatively, a position regulating member that regulates the misalignment between the coil and the shield member may be provided. This makes it possible to prevent the magnetic field reduction effect of the shield member from being changed due to the displacement of the coil.

In the first embodiment, the movable frame 51 is made of resin, but the movable frame 51 may be formed of a conductive member. In this case, it is desirable that the shield member has a higher conductivity than the movable frame 51.

Further, in order to reinforce the resin-based movable frame 51, a conductor (insert member) integrally molded with the movable frame 51 by insert molding may be made to circulate around the outer circumference of the coil to form a shield member. .. At this time, the insert-molded shield member may be provided with a position regulating mechanism for regulating the position of the coil. Alternatively, a position regulating member that regulates the misalignment between the coil and the insert-molded shield member may be provided. As a result, it is possible to reduce the size and weight of the blur correction unit and reduce the adverse effect of the magnetic field on the image sensor 6 while preventing the magnetic field reduction effect from changing due to the displacement of the coil.

Here, in order to confirm the magnetic field canceling effect of the shield member according to the first embodiment, an electromagnetic field simulation was performed as follows.

FIG. 7 is a diagram showing a model of electromagnetic field simulation. 7 (a) is a perspective view showing an electromagnetic field simulation model, and FIG. 7 (b) is a view of the coil and the shield member as viewed from above.

Further, FIG. 8 is a diagram showing a simulation result relating to a magnetic field reaching the observation surface corresponding to the position of the image sensor when the shape of the shield member is changed. 8 (a) is a diagram showing a simulation result when the thickness of the shield member is changed, and FIG. 8 (b) is a diagram showing a simulation result when the width of the shield member is changed. The electromagnetic field simulation was performed using a commercially available electromagnetic field simulation (“Maxwell3D” manufactured by Ansys).

In FIG. 7, L1 indicates the length of the short side of the hollow portion of the coil 111, and L2 indicates the length of the long side of the hollow portion. Then, L3 indicates the length on the outer peripheral short side side of the coil 111, and L4 indicates the length on the outer peripheral long side side. Here, the cross-sectional height of the coil 111 is h, and the length in the width direction is w1.

In this model, for example, L1 is 3 mm, L2 is 17 mm, L3 is 9 mm, L4 is 23 mm, h is 2 mm, and w1 is 3 mm. The molded shield member 112 is arranged in a sheet shape with a space of 0.5 [mm] from the coil 111, and has a substantially rectangular shape. In the shield member 112, the thickness in the same direction as the width w1 of the coil 111 is t, and the width in the same direction as the height h of the coil 111 is w2.

Here, the magnetic field reaching the observation surface M corresponding to the position of the image sensor when the thickness t and the width w2 of the shield member 112 are changed is simulated. The observation surface M was formed into a sheet having a length of 18 mm and a width of 28 mm, and the maximum value of the magnetic field reaching the inside of the observation surface M was simulated.

The position of the observation surface M is in a direction parallel to the winding axis corresponding to the Z axis shown in FIG. 7, and the distance between the winding axis center 124 of the coil 111 and the center point 123 of the observation surface M is 5.6 mm. Further, the distance in the plane substantially orthogonal to the winding axis of the coil 111 is set to 25.6 mm in the direction parallel to the short side of the coil 111 corresponding to the X axis shown in FIG. 7, and further, the long side corresponding to the Y axis. It was set to 6.4 mm in the direction parallel to. The lateral direction of the observation surface M and the long side of the coil 111 are parallel to the Y axis.

In performing the electromagnetic field simulation, the material of the coil 111 was copper, and the conductivity was 58000000 S / m. Further, the material of the shield member 112 was aluminum, and the conductivity was 38000000 S / m. Then, a sinusoidal current having a frequency of 300 kHz and an amplitude of about 610 mA was applied to the coil 111.

FIG. 8A shows the simulation results in the state where the shield member 112 does not exist, and when the width w2 is 2 mm and the thickness t is changed from 0.01 mm to 0.5 mm in the shield member 112. ing.

In FIG. 8A, the horizontal axis represents the thickness t of the shield member 112, and the vertical axis represents the reduction rate [%] of the maximum magnetic field reaching the observation surface M with reference to the state in which the shield member 112 does not exist.

FIG. 8B shows the simulation results in the state where the shield member 112 does not exist, and when the thickness t is 0.04 mm and the width w2 is changed from 0.1 mm to 2 mm in the shield member 112. ing.

In FIG. 8B, the horizontal axis represents the width w2 of the shield member 112, and the vertical axis represents the reduction rate [%] of the maximum magnetic field reaching the observation surface M with reference to the state in which the shield member 112 does not exist.

As shown in FIG. 8A, it can be seen that the magnetic field reaching the observation surface M decreases as the thickness t of the shield member 112 becomes thicker. Specifically, the reduction rate greatly increases up to a thickness t corresponding to a skin depth of about 0.15 mm, which is obtained from the frequency of the alternating current flowing through the shield member 112 and the conductivity of the shield member 112. Further, at a thickness t corresponding to a skin depth of about 0.15 mm or more, the rate of increase in the reduction rate becomes gradual. That is, the current flowing through the shield member 112 due to the coupling of the magnetic fields of the coil 111 contributes to the effect of reducing the magnetic field, so that the above-mentioned state is obtained.

As can be easily understood from FIG. 8A, the magnetic field reaching the observation surface M is about 30% even if the thickness t of the shield member 112 is about 0.015 mm, which is 1/10 times the skin depth. It can be reduced. Therefore, it is desirable that the thickness t of the shield member 112 is at least about 1/10 times the skin depth obtained from the skin effect. More preferably, the thickness t of the shield member 112 is equal to or greater than the skin depth.

If the shield member 112 is too thick, it is necessary to widen the gap between the coil 53 and the movable frame 51, and the size of the blur correction unit 12 becomes large. In addition, processing becomes difficult and the cost increases. When the thickness t of the shield member 112 is 0.6 mm or more, which is four times the skin depth, the increase in the reduction rate [%] of the magnetic field with respect to the thickness is small.

Therefore, in order to obtain the reduction effect of the shield member 112 while reducing the size, it is desirable that the thickness of the shield member 112 is four times or less the depth of the epidermis. That is, it is desirable that the thickness of the shield member 112 is in the range of 1/10 to 4 times the skin depth required according to the skin effect.

As shown in FIG. 8B, it can be seen that as the width w2 of the shield member 112 increases, the magnetic field reaching the observation surface M decreases. Specifically, the reduction rate increases almost linearly until the width w2 of the shield member 112 is 1/4 times the height h of the coil 111. When the width w2 of the shield member 112 is 1/4 or more of the height h of the coil 111, the reduction rate gradually increases.

As can be easily understood from FIG. 8B, the magnetic field reaching the observation surface M is reduced by about 10% even if the width w2 of the shield member 112 is 0.2 mm, which is 1/10 times the width of the coil 111. can do. Therefore, it is desirable that the width w2 of the shield member 112 is at least 1/10 times the height h of the coil 111.

If the width w2 of the shield member 112 is increased, it will interfere with the permanent magnets arranged so as to face the coil 111 and the FPC on which the coil 111 is mounted. In order to prevent such interference, it is necessary to increase the blur correction unit 14 in the optical axis direction.

Therefore, the width w2 of the shield member 112 is preferably about the same as the height h of the coil 111 at the maximum, and the width w2 of the shield member 112 is 1.2 of the coil 111 in consideration of manufacturing variations of the coil 111 and mounting position deviation. It is desirable to double or less. That is, it is desirable that the width of the shield member 112 in the axial direction of the coil is in the range of 1/10 to 1.2 times the length in the axial direction of the coil.

As described above, in the first embodiment of the present invention, the blur correction device (blurring correction unit) can be miniaturized to reduce the influence of the magnetic field on the image sensor.

[Second Embodiment]
Subsequently, a camera including a blur correction device according to a second embodiment of the present invention will be described. The configuration of the camera according to the second embodiment is the same as that of the camera shown in FIG. 1, and the configuration of the blur correction unit 14 is also the same as that of the blur correction unit 14 described with reference to FIGS. 3 and 4.

In the second embodiment, instead of the movable frame 51 described in the first embodiment, a movable frame 57 molded by non-magnetic aluminum die casting is used. Further, in the first embodiment, the coil 53 is arranged in the hole portion of the movable frame 51 so that the movable frame 51 covers the outer circumference of the coil. On the other hand, in the second embodiment, the movable frame 57 is configured to cover only half of the outer circumference of the coil. Then, a shield member which is a sheet-like conductor electrically connected to the movable frame 57 is arranged.

FIG. 9 is a perspective view showing a movable frame, a shield member, and a coil in the blur correction unit used in the camera according to the second embodiment of the present invention. Here, the outer shape of the image sensor 6 is shown by a broken line.

With reference to FIG. 9, here, the outer peripheral portion of the coil covered by the movable frame 57 will be described by the coil 53a. When a straight line 92 parallel to the side closest to the image sensor 6 is drawn through the center of the winding axis of the coil 53a, the movable frame 57 covers the outer peripheral portion of the coil 53a on the side closer to the image sensor 6 with respect to the straight line 92. cover. Similarly, for the coils 53b and 53c, a straight line passing through the center of the winding axis of the coil is drawn to divide the region in half so that the side close to the image sensor 6 is covered with the movable frame 57.

With such a configuration, the size of the movable frame 57 can be reduced and the blur correction unit 14 can be miniaturized.

Next, the configuration of the shield member will be described with reference to the shield member 58a. The shield member 58a is electrically conductive with the movable frame 57. By connecting the movable frame 57 and the shield member 58a, the outer peripheral portion of the coil 53a is covered. Specifically, the movable frame 57 connects the sheet-shaped conductors 58a to the ends 121 and 122 of the outer peripheral halves that cover the coil 53a, and the shield member 58a has a surface facing the outer peripheral portion of the coil 53a. Similarly for the coils 53b and 53c, the movable frame 57 covers the outer peripheral halves of the coils 53b and 53c, respectively.

The sheet-shaped conductors 57b and 57c are connected to the ends of the outer peripheral halves of the coils 53b and 53c covered by the movable frame 57 and are arranged so as to have a surface facing the coils 53b and 53c.

In this way, the movable frame 57 and the shield member cover the outer periphery of the coil 53.

The magnetic field reduction effect due to the arrangement of the shield members 58a to 58c will be described.

As described above, the electrically conductive movable frame 57 and the shield members 58a to 58c cover the outer periphery of the coil 53. When the magnetic fields of the coils 53a to 53c are coupled to the movable frame 57 and the shield members 58a to 58c, a current is generated in the direction opposite to that of the coils 53a to 53c. Due to this current, a magnetic field is generated in a direction that cancels the magnetic field generated by the coils 53a to 53c, and the magnetic field reaching the image sensor 6 can be reduced.

In the second embodiment, the blur correction unit 14 can be made smaller. For example, when the coils 53a to 53c are arranged in the holes of the movable frame as described in the first embodiment, the outer periphery of the coils is covered with a wall surface defining the holes. In this case, due to strength and manufacturing restrictions, the wall surface portion of the coils 53a to 53c that defines the pores covering the outer periphery on the side far from the image sensor needs to have a constant thickness.

On the other hand, in the second embodiment, the shield members 58a to 58c, which are thin sheet-like conductors, are arranged on the outer periphery of the coils 53a to 53c on the side far from the image sensor 6. As a result, the size of the blur correction unit 14 can be reduced.

Further, in the second embodiment, the weight of the movable portion 50 can be reduced. As described above, the outer peripheral halves of the coils 53a to 53c are covered with the movable frame 57, and the remaining outer peripheral halves are covered with the shield members 58a to 58c which are sheet-like conductors. As a result, a part of the movable frame 57 can be replaced with a lightweight sheet-like conductor as compared with the case where the coils 53a to 53c are arranged in the holes of the movable frame. As a result, the weight of the movable portion 50 can be reduced, and the weight of the blur correction portion 14 can be reduced.

Further, in the second embodiment, the power consumption of the blur correction unit 14 can be reduced. As described above, in the second embodiment, the weight of the movable portion 50 can be reduced. By reducing the weight of the movable portion 50, the force required for driving the movable portion 50 or holding the movable portion 50 at the position of the movable portion 50 at the time of blur correction can be reduced. As a result, the power consumption of the blur correction unit 14 can be reduced.

As described above, in the second embodiment of the present invention, the movable frame 57 and the shield members 58a to 58c cover the outer periphery of the coils 53a to 53c, so that the blur correction unit 14 is miniaturized and the magnetic field with respect to the image sensor 6 is reduced. The influence of can be reduced.

In the second embodiment, the arrangement of the shield members 58a to 58c has been described, but it is not necessary to use the shield members 58a to 58c. For example, it may be applied to at least one or more coils such as those having a particularly short distance from the image sensor 6.

Further, in the second embodiment, the movable frame 57 covers half of the outer circumference of the coils 53a to 53c, but it is not necessary to apply to all of the coils 53a to 53c, and it is applied to at least one or more coils. You may do so.

By the way, in order to generate a canceling magnetic field, a structure may be provided in which the outer periphery of the coils 53a to 53c is covered by the movable frame 57 and the shield members 58a to 58c. Therefore, the movable frame 57 is not limited to the case where the movable frame 57 covers half of the outer periphery of the coils 53a to 53c, and may be configured to cover at least a part thereof. Alternatively, the outer circumference of the coils 53a to 53c may be covered by more than half.

Further, in the second embodiment, the outer periphery of the coil 53 may be covered by the electrically conductive movable frame 57 and the shield members 58a to 58c. Therefore, for example, a notch or the like may be formed in the movable frame 57 or the shield members 58a to 58c in order to pass the lead wire connecting the FPC 55 and the coils 53a to 53c.

In addition, the shield members 58a to 58c may be conductive members in which the coils 53a to 53c are arranged on a surface opposite to the surface on which the FPC 55 is mounted. For example, a metallic backing member (metal member) arranged to prevent the FPC 55 from bending may be used as the shield members 58a to 58c.

FIG. 10 is a diagram for explaining an example in which a backing member is used as a shield member in the blur correction unit according to the second embodiment of the present invention. 10 (a) is a perspective view showing the movable frame, the coil, and the lining member, and FIG. 10 (b) is a perspective view seen from the opposite side in the direction of the optical axis.

In FIG. 10A, the upper surface is the subject side, and in FIG. 10B, the backing member is the lower surface side. Further, here, the outer shape of the image sensor 6 is shown by a broken line.

The coils 53a to 53c are mounted on the FPC 55 (not shown in FIG. 10). The conductive lining member 59 is arranged on the surface of the coils 53a to 53b opposite to the mounting surface of the FPC 55. The lining member 59 has a bent portion that constitutes the shield members 58a to 58c. The bent portion of the backing member 59 is connected to the movable frame 57 at the end of the outer peripheral half of the movable frame 57 covering the coil 53a.

With the above configuration, the influence of the magnetic field on the image sensor 6 can be reduced without adding a new shield member. It should be noted that the coil 53a to 53c may be provided with a misalignment prevention mechanism for preventing the misalignment. This makes it possible to prevent the magnetic field reduction effect of the shield members 58a to 58c from changing due to the displacement of the coil 53.

As described above, also in the second embodiment of the present invention, the blur correction device (blurring correction unit) can be miniaturized to reduce the influence of the magnetic field on the image sensor.

5 Camera system control unit 6 Image sensor 14 Blur correction unit (Blur correction device)
50 Movable part 51 Movable frame 53a to 53c Coil 56a to 56c Shield member

Claims (12)

The image is used in an electronic device including an image sensor that outputs an image signal corresponding to an optical image imaged via the image pickup optical system, and the image pickup element is moved in a direction orthogonal to the optical axis of the image pickup optical system. It is a blur correction device that corrects the blur that occurs in the image indicated by the signal.
A movable member that holds the image sensor and can move in a direction orthogonal to the optical axis.
A coil arranged on the movable member and supplied with electric power,
It has a permanent magnet and is arranged so as to face the coil.
The movable member is moved by the coil and the permanent magnet,
A blur correction device characterized in that a conductive member is arranged on the outer circumference of the coil. Further, a mounting member arranged on the movable member and on which the coil is mounted and a mounting member
A fixing member provided in the electronic device includes a support member that movably supports the movable member.
The blur correction device according to claim 1, wherein the permanent magnet is arranged on the fixing member. The blur correction device according to claim 2, wherein the conductive member is formed in a sheet shape. The blur correction device according to any one of claims 1 to 3, wherein the conductive member has a higher conductivity than the movable member. The movable member is molded of resin, and the movable member is integrally provided with a conductive insert member.
The blur correction device according to any one of claims 1 to 4, wherein the conductive member is a part of the insert member. The movable member is formed of a conductive material and includes a metal member electrically connected to the conductive member.
The blur correction device according to any one of claims 1 to 4, wherein the metal member and the conductive member are located on the outer periphery of the coil. The movable member is formed of a conductive material and includes a metal member electrically connected to the conductive member.
The mounting member includes a non-magnetic conductive member arranged on a surface opposite to the surface on which the coil is mounted and electrically connected to the metal member.
The blur correction device according to claim 2, wherein the conductive member is a part of the non-magnetic conductive member. The blur correction device according to any one of claims 1 to 7, wherein the conductive member is provided with a position regulating mechanism for regulating the position of the coil. The blur correction device according to any one of claims 1 to 8, wherein the thickness of the conductive member is in the range of 1/10 to 4 times the skin depth required according to the skin effect. .. Any one of claims 1 to 9, wherein the width of the conductive member in the axial direction of the coil is in the range of 1/10 to 1.2 times the length of the coil in the axial direction. The blur correction device described in the section. The blur correction device according to any one of claims 1 to 10.
A control means for controlling the electric power applied to the coil according to the image signal output from the image sensor, and
An electronic device characterized by being equipped with. The electronic device is an electronic device having an image processing means for generating image data by performing predetermined image processing on an image signal output from the image sensor.

Images