JPWO2009031542A1 - Magnetic drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a movable part using a magnet and a coil and to accurately detect the moving position of the movable part using a magnetic detection part facing the magnet. A movable part is provided with a magnet 21, and a fixed part is provided with a coil 22 and a magnetic detection part 23. The magnetic detection unit 23 is disposed on the side of the coil 22 and at a position that does not overlap the magnet 21 in the vertical direction. The magnet 21 is moved in the Y direction by the magnetic flux generated from the facing surface 21 a of the magnet 21 and the current flowing through the coil 22. The magnetic detection unit 23 can detect the magnetic field component in the XY plane, and can detect the moving position of the magnet 21 based on the detection output. In addition, since the magnetic detection unit 23 does not react to the magnetic field component in the XZ plane, the detection output of the magnetic detection unit 23 is not affected by the current magnetic field generated by the current flowing through the coil 22. [Selection] Figure 2

Description

  The present invention relates to a magnetic drive apparatus that moves a movable part linearly or two-dimensionally along an XY plane, and more particularly to a magnetic drive apparatus that can detect the movement position of the movable part with high accuracy.

  A magnetic drive device that moves a movable part linearly or two-dimensionally is generally provided with a coil in which a magnet flows in one of the fixed part and the movable part, and a coil through which a current crossing a magnetic field generated from the magnet flows. The movable part is moved by the electromagnetic force generated by the magnetic field generated from the magnet and the current flowing through the coil. In addition, as this type of magnetic drive device, a magnetic detection unit is provided on the fixed unit or movable unit side, and the moving position and moving speed of the movable unit are detected by the output from the magnetic detection unit, and depending on the detection state In some cases, the current to the coil is controlled.

  For example, in a digital camera or a video camera, a magnet for moving a lens holder in the X direction is supported so that a lens holder holding a lens can move in an XY plane orthogonal to the optical axis of the lens. A coil and a magnet and a coil for moving the lens holder in the Y direction are provided. Further, a magnetic detection unit that detects the movement position or movement speed of the lens holder in the XY direction and an acceleration detector that detects acceleration due to camera shake acting on the camera are provided.

  When acceleration due to camera shake is detected by the acceleration detector, the movement amount and movement speed of the lens holder for canceling the camera shake amount are calculated from the detection output. Then, the coil is energized and the moving position and moving speed of the lens holder are detected by the magnetic detection unit, and the lens holder is controlled to perform an operation to cancel camera shake.

In the following Patent Document 1 and Patent Document 2, a Hall element is provided as a magnetic detection unit for detecting the movement position of the lens holder. This Hall element is provided on the same side as the coil, and by detecting the magnetic field from the driving magnet by this Hall element, the moving amount and moving speed of the lens holder can be detected.
JP-A-10-26779 JP 2007-25124 A

  However, in the devices described in Patent Document 1 and Patent Document 2, since the position of the lens holder is detected by detecting the magnetic field from the driving magnet with the Hall element, the Hall element is located near the coil. It is necessary to install. As a result, the Hall element reacts not only by the magnetic field from the magnet, but also by the current magnetic field when a current flows through the coil. If the Hall element reacts to the current magnetic field of the coil, the Hall element cannot accurately know the moving position of the movable part.

  In order to solve this problem, the current supply time to the coil and the detection time by the Hall element are controlled so as not to overlap in time so that the current magnetic field of the coil does not affect the Hall element. It is necessary. However, this makes the circuit configuration extremely complicated.

  Or it becomes necessary to make the magnet detected by the Hall element different from the driving magnet, and the number of magnets increases, resulting in new problems such as an increase in the load on the movable part.

  The present invention solves the above-described conventional problems, and can detect the magnetic position from the driving magnet by the magnetic detection unit to know the moving position and moving speed of the movable unit, and the current flows through the coil. It is an object of the present invention to provide a magnetic drive device that prevents the magnetic detection unit from reacting with the current magnetic field and can control the moving position of the movable unit with high accuracy at all times.

The present invention includes a fixed portion and a movable portion, wherein a magnet is provided on one of the fixed portion and the movable portion, and on the other side, a coil through which a current crossing a magnetic field generated from the magnet flows, and the magnet In a magnetic drive device provided with a magnetic detection unit for detecting a magnetic field emitted from
The coil includes a pair of driving action portions through which current flows in a direction orthogonal to the moving direction of the movable portion and a connecting portion connecting the driving action portions, and the magnet faces the driving action portion. There is an opposing surface, and this opposing surface is magnetized in the moving direction in which one is an N pole and the other is an S pole, and a current flowing in the driving action part and a magnetic field applied to the driving action part from the opposing face A moving force is given to the movable part.
The magnetic detection unit detects a change in a magnetic field in a plane parallel to both the direction of current flow and the movement direction in the driving action unit, and the magnetic detection unit is the connection unit of the coil. The movement of the movable part can be detected by detecting a change in the component of the magnetic field in the plane emitted from the magnet. It is characterized by that.

  In the magnetic drive device of the present invention, the magnetic detection unit detects a change in the magnetic field in a plane parallel to both the direction in which the current flows in the drive action unit of the coil and the moving direction of the movable unit. By disposing the magnetic detection unit at a position that does not overlap the opposing surface of the magnet, it is possible to detect at least one of the intensity and direction of the magnetic field in the plane emitted from the magnet. By this detection operation, the moving position of the movable part can be known. Moreover, although the magnetic detection part is arrange | positioned at the side of the connection part of a coil, the electric current magnetic field by the electric current which flows into this connection part does not have a component which changes in the said plane. Therefore, the magnetic detection unit does not react to the current magnetic field of the coil. Therefore, even if the time for passing a current through the coil and the time for detecting the position by the magnetic detection element overlap, it is possible to prevent the coil magnetic field from adversely affecting the detection of the moving position.

  According to the present invention, the magnetic sensing unit is provided with a magnetoresistive effect element. The magnetoresistive effect element has a fixed magnetic layer in which the magnetization direction is fixed, and a magnetization direction according to an external magnetic field applied from the magnet. And the resistance value changes according to the change in the magnetization direction of the free magnetic layer, and the fixed magnetization direction of the fixed magnetic layer is set parallel to the plane. Can be configured.

  In this case, it is preferable that the direction of pinned magnetization of the pinned magnetic layer is parallel to the direction in which current flows in the driving action unit. Note that the direction of fixed magnetization is not necessarily parallel to the current direction as long as it is parallel to the plane and crosses the movement direction.

  The magnetic detection unit may be an AMR element as long as it can detect a change in the magnetic field in the plane and does not react to a magnetic field (coil current magnetic field) in a direction crossing the plane. Alternatively, the Hall element may be arranged such that the detection direction is directed toward the current direction.

  For example, in the present invention, the movable part is supported by the fixed part so as to move in the X direction and the Y direction orthogonal to each other, and the magnet, the coil, and the coil for moving the movable part in the X direction The magnet, the coil, and the magnetic detection unit for moving the magnetic detection unit and the movable unit in the Y direction can be configured.

  In this case, the movable part may be provided with a lens holder for holding a lens.

  In the present invention, since the magnetic detection unit detects the magnetic field generated from the magnet for driving the movable part and detects the moving position of the movable part, the number of magnets can be minimized. In addition, even if the magnetic detection unit is arranged on the side of the coil, the magnetic detection unit does not react to the current magnetic field of the coil, so that even when the coil is energized, the movable part is detected by the detection output from the magnetic detection unit. Can be detected with high accuracy.

  FIG. 1 is a perspective view showing a magnetic drive device 1 according to an embodiment of the present invention. 2 and 3 are a side view of the driving / detecting unit provided in the magnetic driving device 1 as seen from the line of sight in the Y1 direction and a plan view seen from the line of sight in the Z2 direction. 4A and 4B are end views as viewed from the line of sight in the X1 direction for explaining the operation of the drive / detection unit. FIG. 5 is a plan view seen from the line of sight in the Z2 direction for explaining the operation of the drive / detection unit. FIG. 6 is a partially enlarged view of FIG.

  The magnetic drive device 1 shown in FIG. 1 moves the 1st movable part 2 within an XY plane. A lens holder 3 is formed integrally with the first movable portion 2, and a camera lens 4 is held on the lens holder 3. The magnetic drive device 1 of this embodiment is used as a camera shake correction device.

  The magnetic drive device 1 is provided with a second movable portion 5 that is an intermediate movable portion. The second movable part 5 has a frame shape, and a pair of first guide shafts 6, 6 extending linearly in the X direction and parallel to each other are provided inside the second movable part 5. Yes. Bearing portions 2 a and 2 a are integrally formed on both side portions of the first movable portion 2. The first guide shafts 6 and 6 are slidably inserted into the bearing portions 2a and 2a, and the first movable portion 2 is supported to be movable in the X1-X2 direction with respect to the second movable portion 5. ing.

  Outside the second movable portion, a pair of second guide shafts 7 and 7 are provided that extend linearly in the Y direction and are arranged in parallel to each other. Both end portions of each of the second guide shafts 7 and 7 are fixed to a base of a fixing portion (not shown). The second movable portion 5 is provided with a bearing portion 8 that integrally protrudes from two locations in the X1 direction and the X2 direction, respectively. The second guide shaft 7 is slidably inserted into the bearing portion 8, and the second movable portion 5 is supported so as to be movable in the Y1-Y2 direction with respect to the fixed portion.

  With the above support and guide mechanism, the first movable portion 2 having the lens holder 3 can be moved two-dimensionally in the XY plane.

  A first drive / detection unit 10 is provided between the first movable unit 2 and the second movable unit 5. By the first driving / detecting unit 10, the first movable unit 2 is moved in the X1-X2 direction, and the moving position and moving speed in the X1-X2 direction can be detected. In the first drive / detection unit 10, a magnet 11 is fixed to the bearing portion 2 a of the first movable unit 2. A support surface 5a is formed on the Y2 side of the second movable unit 5, and the coil 12 and the magnetic detection unit 13 are fixed to the support surface 5a.

  A second driving / detecting unit 20 is provided between the second movable unit 5 and the fixed unit. The second driving / detecting unit 20 moves the second movable unit 5 to Y1-Y2, and detects the moving position and moving speed in the Y1-Y2 direction. In the second drive / detection unit 20, the magnet 21 is fixed to the movable support plate 9 fixed between the bearing units 8, 8 located on the X2 side of the second movable unit 5. The fixed part is provided with a fixed side support plate 24, and the coil 22 and the magnetic detection unit 23 are fixed to the fixed side support plate 24.

  The camera lens 4 provided in the first movable unit 2 is controlled by controlling energization to the coil 12 of the first drive / detection unit 10 and energization to the coil 22 of the second drive / detection unit 20. Can be moved within the XY plane, and the output from the magnetic detection unit 13 provided in the first drive / detection unit 10 and the second drive / detection unit 20 are provided. The movement position and movement speed of the optical axis O can be detected by the output from the magnetic detection unit 23.

  Note that the structure of the support and guide mechanism of the movable part having the lens holder 3 and the first and second drive / detection parts is not limited to that shown in FIG. 1, and moves in the X direction on the fixed part, for example. The X stage and the Y stage that moves in the Y direction on the fixed portion may be provided in an overlapping manner. For example, the movable part is supported so as to be movable in the X direction on the Y stage, and the movable part is moved in the X direction by the moving force of the X stage. The movable part is supported so as to be movable in the Y direction on the X stage, and the movable part is moved in the Y direction by the moving force of the Y stage. In this case, the first drive / detection unit 10 is provided between the X stage and the fixed unit, and the second drive / detection unit 20 is provided between the Y stage and the fixed unit.

  In the magnetic drive device 1 shown in FIG. 1, the configurations of the first drive / detection unit 10 and the second drive / detection unit 20 are substantially the same, and the difference is the first drive / detection unit 10. Then, the magnet 11 moves in the X direction, and the second drive / detection unit 20 is different only in the moving direction so that the magnet 21 moves in the Y direction.

  Therefore, in the following, the detailed structure and operation principle of the second drive / detection unit 20 will be described.

  In the second driving / detecting unit 20, the direction of the driving force applied to the magnet 21 is the Y1-Y2 direction, and the Y1-Y2 direction is the moving direction.

  In FIG. 3, the plane of the coil 22 is shown. As shown in FIG. 3, the coil 22 includes a drive action part 22 a and a drive action part 22 b. Moreover, it has the X2 side connection part 22c and the X1 side connection part 22d which connect the drive action part 22a and the drive action part 22b. In the coil 22, a plurality of conductive wires are wound around the XY plane so as to circulate in the order of the drive action part 22 a, the connection part 22 d, the drive action part 22 b, and the connection part 22 c.

  In the drive action part 22a and the drive action part 22b, an electric current flows into the X1-X2 direction orthogonal to the Y1-Y2 direction which is a moving direction. And in the drive action part 22a and the drive action part 22b, the directions through which the current flows are opposite to each other. Further, in the connecting portion 22c and the connecting portion 22d, the direction in which the current flows is substantially the same as the Y1-Y2 direction that is the moving direction.

  As shown in FIGS. 2 and 4, the magnet 21 is a facing surface 21 a whose lower surface facing the Z <b> 2 side faces the coil 22. The opposing surface 21a and the upper surface 21b facing the Z1 side are planes parallel to each other. The magnet 21 has an end face 21c facing the X2 side and an end face 21d facing the X1 side. The end surface 21c and the end surface 21d are planes parallel to each other, and are orthogonal to the facing surface 21a and the upper surface 21b. The magnet 21 has a side surface 21e facing the Y1 side and a side surface 21f facing the Y2 side. The side surface 21e and the side surface 21f are planes parallel to each other, and are surfaces orthogonal to the facing surface 21a and the upper surface 21b.

  As shown in FIG. 3, the side surfaces 21e and 21f are longer than the end surfaces 21c and 21d, and the opposing surface 21a and the upper surface 21b have a rectangular shape whose longitudinal direction is the X direction.

  As shown in FIGS. 4A and 4B, the opposing surface 21a is provided with a magnetization boundary line L1 at the center that is divided in the Y direction, and this magnetization boundary line L1 extends linearly in the X direction. ing. Further, a magnetization boundary line L2 is also provided on the upper surface 21b, and this magnetization boundary line L2 also extends linearly in the X direction.

  As shown in FIG. 4, on the facing surface 21a, the Y1 side is magnetized to the S pole and the Y2 side is magnetized to the N pole across the magnetization boundary line L1. Therefore, on the upper surface 21b, the Y1 side is magnetized to the N pole and the Y2 side is magnetized to the S pole across the magnetization boundary line L2.

  As shown in FIG. 2, the magnetic detection unit 23 is mounted on a base 25 fixed on the fixed support plate 24, and the upper surface on the Z1 side of the magnetic detection unit 23 and the Z1 side of the coil 22. The level difference between the top and the bottom is minimized.

  As shown in FIGS. 2 to 5, the magnetic detection unit 23 is located on the X2 side of the outer surface of the coupling portion 22 c on the X2 side of the coil 22. Moreover, the magnetic detection part 23 is located in the X2 side rather than the position of the end surface 21c of the magnet 21, and the magnetic detection part 23 is arrange | positioned in the position which does not overlap with the opposing surface 21a of the magnet 21 in an up-down direction (Z direction). Has been. In the magnetic detection unit 23, a magnetoresistive effect element 30 is disposed in a case made of a nonmagnetic material, and the magnetoresistive effect element 30 does not overlap the opposing surface 21a of the magnet 21 in the vertical direction. Is arranged. Preferably, the magnetoresistive effect element 30 is arranged so as to be separated from the end face 21c of the magnet 21 by a predetermined distance on the X2 side. If the magnetoresistive effect element does not overlap the facing surface 21a, the case of the magnetic detection unit 23 may overlap the facing surface 21a vertically.

  FIG. 8A is a plan view of the magnetoresistive effect element 30, and FIG. 9 is a cross-sectional view of the element portion 31 of the magnetoresistive effect element 30 taken along the cutting plane IX of FIG.

  The magnetoresistive effect element 30 is a so-called GMR element utilizing a giant magnetoresistive effect. In the magnetic detection unit 23, the magnetoresistive effect element 30 can detect a change in the strength of the magnetic field and a change in the direction of the magnetic field in the XY plane, and react to a magnetic field in a direction crossing the XY plane. Arranged not to.

  As shown in FIG. 8A, the magnetoresistive effect element 30 has a plurality of element portions 31 formed in parallel to each other, and two front and rear end portions of each element portion 31 are connected by connection electrodes 41 and 42, respectively. It is connected. Furthermore, extraction electrodes 43 and 44 are connected to the element portions 31 located at both left and right ends in the figure. Therefore, each element part 31 is connected in series and the meander type | mold pattern is comprised.

  As shown in the cross-sectional view of FIG. 9, each element unit 31 is laminated on a substrate 32 in the order of an antiferromagnetic layer 33, a pinned magnetic layer 34, a nonmagnetic conductive layer 35, and a free magnetic layer 36. A film is formed, and the surface of the free magnetic layer 36 is covered with a protective layer 37.

  The antiferromagnetic layer 33 is made of an antiferromagnetic material such as an Ir—Mn alloy (iridium-manganese alloy). The pinned magnetic layer 34 is formed of a soft magnetic material such as a Co—Fe alloy (cobalt-iron alloy). The nonmagnetic conductive layer 35 is made of Cu (copper) or the like. The free magnetic layer 36 is made of a soft magnetic material such as a Ni—Fe alloy (nickel-iron alloy). The protective layer 37 is a Ta (tantalum) layer.

  In the element unit 31, the magnetization direction of the pinned magnetic layer 34 is fixed by antiferromagnetic coupling between the antiferromagnetic layer 33 and the pinned magnetic layer 34. As shown in FIGS. 8A and 8B and FIG. 9, in each element part 31, the fixed magnetization direction (P direction) of the fixed magnetic layer 34 is orthogonal to the longitudinal direction of the element part 31. The direction of fixed magnetization (P direction) of the fixed magnetic layer 34 is the X2 direction. That is, as shown in FIG. 5, the direction of fixed magnetization (P direction) is a vector in a plane parallel to the XY plane, and is orthogonal to the Y1-Y2 direction, which is the driving direction acting on the magnet 21. The direction.

  In the magnetoresistive effect element 30, the electric resistance changes depending on the relationship between the fixed magnetization direction (P direction) of the fixed magnetic layer 34 and the magnetization direction of the free magnetic layer 36. When the magnetization direction of the free magnetic layer 36 and the fixed magnetization direction (P direction) of the pinned magnetic layer 34 are the same, the resistance value of the magnetoresistive effect element 30 is minimized, and the magnetization of the free magnetic layer 36 is reduced. When the direction and the direction of the fixed magnetization of the fixed magnetic layer 34 (P direction) are opposite, the resistance value of the magnetoresistive effect element 30 is maximized.

  Since the direction of pinned magnetization of the pinned magnetic layer 34 is the X2 direction and its vector is parallel to the XY plane, the magnetoresistive effect element 30 has a magnetic field component in the XY plane that acts on the free magnetic layer 36. The resistance value changes depending on the relationship between the (magnetic field vector in the XY plane) and the fixed magnetization vector. Therefore, the magnetoresistive effect element 30 has its resistance value changed by a vector component parallel to the XY plane of the external magnetic field, but other components, for example, a magnetic field in the Z direction crossing the XY plane. Does not react to vector components.

  FIG. 10 shows an example of a detection circuit that detects a change in resistance of the magnetoresistive effect element 30 in the magnetic detection unit 23. In this detection circuit, the magnetoresistive effect element 30 and the fixed resistance element 45 are connected in series, and a DC power supply voltage Vcc is applied to the magnetoresistive effect element 30 and the fixed resistance element 45 connected in series at a constant voltage. It is done. An intermediate point 46 between the magnetoresistive effect element 30 and the fixed resistance element 45 is an output portion of a detection output based on a change in the resistance value of the magnetoresistive effect element 30. The electric resistance value of the magnetoresistive effect element 30 when no external magnetic field is applied is the same as the resistance value of the fixed resistance element 45, and the potential at the intermediate point 46 at this time is Vcc / 2.

Next, the operation of the second drive / detection unit 20 will be described.
When the second movable unit 5 shown in FIG. 1 is in the neutral position in the Y1-Y2 direction, as shown in FIG. 3, the second driving / detecting unit 20 bisects the magnet 21 in the Y1-Y2 direction. The center line substantially coincides with the center line that bisects the coil 22 in the Y1-Y2 direction.

  On the facing surface 21a of the magnet 21, a magnetic flux is generated from the N pole on the Y2 side to the S pole on the Y1 side from the magnetization boundary line L1. 4A and 4B, a vector component parallel to the YZ plane in the magnetic flux from the N pole to the S pole is indicated by a magnetic flux component H1.

  As shown in FIG. 4A, the magnetic flux component H1 crosses the drive action portion 22a and the drive action portion 22b of the coil 22. A driving force in the Y1 direction or the Y2 direction is given to the magnet 21 by the electromagnetic force due to the magnetic flux component H1 and the current in the X1-X2 direction flowing through the driving action portions 22a and 22b, and the second movable portion 5 Are moved in the same direction. By controlling the direction and magnitude of the current applied to the coil 22, the moving direction and moving speed of the magnet 21 and the second movable part 5 in the Y1-Y2 direction can be controlled.

  As shown in FIG. 4B, the magnetic detection unit 23 is located on the lower side (Z2) side of the facing surface 21a of the magnet 21, and as shown in FIG. 5, the X2 side of the end surface 21c of the magnet 21 is located on the X2 side. Is located. As shown in FIG. 4B and FIG. 5, in the magnet 21, there is a magnetic flux from the north pole to the south pole below the facing surface 21a, and below the facing surface 21a and X2 from the end surface 21c. There is also a magnetic flux from the north pole to the south pole on the side.

  4B, the vector component of the magnetic flux in the YZ plane is indicated by a magnetic flux component H1, and in FIG. 5, the vector component of the magnetic flux in the XY plane is indicated by a magnetic flux component H2. . The magnetoresistive effect element 30 in the magnetic detection unit 23 does not react to the magnetic flux component H1, but reacts only to the magnetic flux component H2 in the XY plane.

  As shown in FIGS. 5 and 8A, in the magnetoresistive effect element 30, the direction of the fixed magnetization (P direction) of the fixed magnetic layer 34 is oriented in the X2 direction in the XY plane. Therefore, when the magnet 21 moves in the Y1 direction from the neutral position shown in FIG. 5, the magnetic flux applied to the magnetoresistive effect element 30 is oriented between the X2 direction and the Y2 direction, and the resistance value of the magnetoresistive effect element 30 decreases. To do. Therefore, the output voltage at the intermediate point 46 shown in FIG. When the magnet 21 moves in the Y2 direction from the neutral position shown in FIG. 5, the magnetic flux applied to the magnetoresistive effect element 30 is oriented between the X1 direction and the Y1 direction, and the resistance value of the magnetoresistive effect element 30 increases. Therefore, the output voltage at the intermediate point 46 is increased.

  Based on the output voltage obtained from the magnetic detector 23, the moving position of the magnet 21 in the Y1-Y2 direction can be known.

  Next, in the second driving / detecting unit 20, a driving force is applied to the magnet 21 by energizing the coil 22, but as shown in FIG. 6, when a current flows through the connecting portion 22c of the coil 22, A current magnetic field Ha is generated around. The vector of the current magnetic field Ha is in the XZ plane and has almost no component in the XY plane. Therefore, the magnetoresistive effect element 30 in the magnetic detection unit 23 hardly reacts with the current magnetic field Ha when the connection unit 22c is energized.

FIG. 7 is a comparative example for comparison with the embodiment of the present invention.
In this comparative example, a magnetic detection unit 50 including a Hall element is provided on the side of the coupling portion 22c of the coil 22 provided in the fixed portion. The Hall element is arranged so as to detect the magnetic field strength in the Z2 direction. This Hall element faces the facing surface 21a of the magnet 21 provided in the movable part. By detecting the magnetic flux component H1 in the XY plane of the magnetic flux when the magnet 21 moves in the Y1-Y2 direction with the Hall element, the moving position of the magnet 21 in the Y1-Y2 direction can be known.

  However, in the comparative example shown in FIG. 7, since the current magnetic field Ha generated from the connecting portion 22c when the coil 22 is energized is detected by the Hall element of the magnetic detection unit 50, this current magnetic field becomes noise, The moving position of the magnet 21 cannot be detected accurately. Therefore, complicated control such as setting the energization time to the coil 22 and the detection time by the magnetic detection unit 50 so as not to overlap is necessary.

  On the other hand, in the embodiment of the present invention shown in FIG. 6, the current magnetic field Ha does not affect the detection output of the magnetoresistive effect element 30 in the magnetic detection unit 23, so that the coil 21 is energized to move the magnet 21. At the same time, the moving position of the magnet 21 can be known with high accuracy by the output from the magnetic detection unit 23 at the same time.

  When the magnetic drive device 1 shown in FIG. 1 is used as a camera shake correction device, the camera is equipped with an acceleration sensor together with the magnetic drive device 1. The acceleration detected by the acceleration sensor is integrated and converted into a speed, and a driving current for canceling the speed is applied to the coil 12 of the first driving / detecting unit 10 and the coil 22 of the second driving / detecting unit 20. Is given. The moving position of the lens holder 3 at this time is detected by the magnetic detection unit 13 and the magnetic detection unit 23, and the moving position and moving speed of the lens holder are detected from the detection output, and the lens holder 3 is moved in the direction of camera shake. The movement of the camera shake is canceled out by moving in the opposite direction.

  In the above-described embodiment, the magnetoresistive effect element 30 which is a GMR element is mounted in the magnetic detection unit 23. However, this may be an AMR element. Alternatively, a Hall element may be provided in the magnetic detection unit 23, and the Hall element may be arranged in a direction to detect the intensity of the magnetic field in the X1-X2 direction. Further, as a magnetoresistive effect element equivalent to the GMR element, a so-called TMR element in which a nonmagnetic insulating layer is provided instead of the nonmagnetic conductive layer 35 and current is applied in the thickness direction of each layer may be used.

  When the magnetoresistive effect element 30 which is a GMR element is used for the magnetic detection unit 23 as in the above embodiment, the free magnetic layer 36 of the GMR element has a magnetic field applied from the magnet 21 as shown in FIG. In response to the magnetic flux vector in the XY plane, the magnet is magnetized in the direction of the vector, and the resistance value changes depending on the magnetization direction. Therefore, detection noise due to disturbance can be reduced compared to other magnetic detection elements.

  For example, in FIG. 5, even if the magnet 21 moves in the Y1-Y2 direction and also moves in the X1-X2 direction, as long as the magnet 21 does not move excessively in the X direction, the magnet 21 is in the Y1-Y2 direction. The vector of the magnetic field in the XY plane given to the magnetic detection unit 23 when moving in the direction does not vary greatly. Therefore, the movement amount in the Y1-Y2 direction can be detected with relatively high accuracy. The same applies to TMR elements.

  In the first drive / detection unit 10 and the second drive / detection unit 20, the coils 12, 22 and the magnetic detection units 13, 23 may be provided in the movable part, and the magnet may be provided in the fixed part.

  Further, in the porcelain driving device of the present invention, the movable portion may move only linearly in one direction.

The perspective view which shows the magnetic drive device of embodiment of this invention, A side view of the second drive / detection unit 20 as seen in the line of sight in the Y1 direction, The top view which looked at the 2nd drive and detection part 20 with the look of the Z2 direction, 4 (A) and 4 (B) are end views of the second drive / detection unit 20 as viewed in the line of sight in the X1 direction. FIG. 3 is a partially enlarged view of FIG. 2 is a partial side view of FIG. The same partial side view as FIG. 2 showing a comparative example, (A) is a plan view showing the structure of the magnetoresistive effect element, (B) is an explanatory diagram showing the relationship between the magnetization direction of the pinned magnetic layer of the magnetoresistive effect element and the direction of the external magnetic field, FIG. 9 is a cross-sectional view of the element portion of the magnetoresistive effect element, and is a cross-sectional view cut along a cutting plane IX in FIG. A circuit diagram showing an example of the circuit configuration of the detector,

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic drive device 2 1st movable part 3 Lens holder 4 Camera lens 5 2nd movable part 6 1st guide shaft 7 2nd guide shaft 10 1st drive and detection part 11 Magnet 12 Coil 13 Magnetic detection part 20 Second drive / detection unit 21 Magnet 21a Opposing surface 21c End surface 22 Coils 22a, 22b Drive action units 22c, 22d Connection unit 23 Magnetic detection unit 30 Magnetoresistive element

Claims (5)

A magnet having a fixed part and a movable part, a magnet is provided on one of the fixed part and the movable part, and on the other side, a coil through which a current crossing the magnetic field generated from the magnet flows and a magnetic field generated from the magnet In a magnetic drive device provided with a magnetic detection unit for detecting
The coil includes a pair of driving action portions through which current flows in a direction orthogonal to the moving direction of the movable portion and a connecting portion connecting the driving action portions, and the magnet faces the driving action portion. There is an opposing surface, and this opposing surface is magnetized in the moving direction in which one is an N pole and the other is an S pole, and a current flowing in the driving action part and a magnetic field applied to the driving action part from the opposing face A moving force is given to the movable part.
The magnetic detection unit detects a change in a magnetic field in a plane parallel to both the direction of current flow and the movement direction in the driving action unit, and the magnetic detection unit is the connection unit of the coil. The movement of the movable part can be detected by detecting a change in the component of the magnetic field in the plane emitted from the magnet. A magnetic drive device characterized by that. The magnetic sensing unit is provided with a magnetoresistive effect element. The magnetoresistive effect element has a fixed magnetic layer in which the magnetization direction is fixed and a magnetization direction that changes according to an external magnetic field applied from the magnet. A magnetic layer, and the resistance value changes according to the change in the magnetization direction of the free magnetic layer,
The magnetic drive device according to claim 1, wherein the direction of fixed magnetization of the fixed magnetic layer is set parallel to the plane.   The magnetic drive device according to claim 1, wherein a direction of fixed magnetization of the fixed magnetic layer is parallel to a direction in which a current flows in the drive action unit.   The movable part is supported by the fixed part so as to move in the X direction and the Y direction orthogonal to each other, and the magnet, the coil, the magnetic detection part, and the magnet for moving the movable part in the X direction, The magnetic drive device according to claim 1, wherein the magnet, the coil, and the magnetic detection unit for moving the movable unit in the Y direction are provided.   The magnetic drive device according to claim 4, wherein the movable part is provided with a lens holder for holding a lens.

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