JP2007068273A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator driven in at least two axial directions. <P>SOLUTION: The actuator 10 is provided with a hollow cylindrical inner yoke 14, a first movable coil 18 axially moved and fitted to an exterior of the inner yoke 14, a permanent magnet 20 for generating a magnetic field orthogonal to the axial direction of the first movable coil 18 and disposed at an exterior of the first movable coil 18 so as to be magnetically coupled to the inner yoke 14, and second movable coils 22a-22d movably disposed in the direction orthogonal to the axial direction. The second movable coils 22a-22d have coil sections 23a-23d disposed at an exterior of the permanent magnet 20 and extending parallel to the axial direction of the first movable coil 18. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an actuator, and more particularly to a lens driving actuator used in a mobile phone or the like equipped with a digital camera.

  In recent years, in a digital camera or the like, in addition to a lens that performs normal zooming and focusing, a lens for correcting imaging blur due to camera shake is mounted, and the lens is driven on the XY plane according to the direction of the blur. Is required.

In addition, since the digital camera is mounted on a mobile phone or the like, the size of the camera is remarkably reduced, and the lens driving actuator itself is required to be small.
JP-A-6-30326 JP-A-8-94905

  An example of a conventional lens driving actuator is disclosed in Patent Documents 1 and 2, but in the technique of Patent Document 1, a pair of coils and permanent magnets must be prepared for driving in one direction. . Therefore, two sets of coils and permanent magnets are required for driving in the two-axis directions, and three sets of coils and permanent magnets are required for driving in the three-axis (XYZ-axis) directions. There was a problem that the actuator itself could not be made small.

  Further, in Patent Document 2, although the yoke is used as a common part, the number of parts is reduced and the lens driving actuator itself is successfully reduced. However, the driving direction of the actuator is only one direction. There is no disclosure of an actuator that is driven in the axial direction or the three-axis (XYZ-axis) direction.

  Therefore, a main object of the present invention is to provide a small actuator that can be driven in at least two axial directions.

  In order to achieve the above-described object, an actuator according to claim 1 includes a hollow cylindrical inner yoke, a first movable coil fitted on the outer side of the inner yoke so as to be movable in the axial direction, and an outer side of the first movable coil. A permanent magnet that is arranged, and at least one second movable coil that has a coil portion that extends parallel to the axial direction of the first movable coil outside the permanent magnet, and is movable in a direction substantially orthogonal to the axial direction The permanent magnet generates a magnetic field in a direction substantially orthogonal to the axial direction of the first movable coil, and electromagnetic force is generated in the first movable coil and the second movable coil by the magnetic field.

  The actuator according to claim 2 is the actuator according to claim 1, and has two second movable coils, and the second movable coils are provided so that directions of electromagnetic forces acting on the second movable coils are different from each other by approximately 90 degrees. It is characterized by being able to.

  The actuator according to claim 3 is the actuator according to claim 2, wherein the first object provided to be interlocked with the first movable coil and the second object provided to be interlockable with the two second movable coils. Is further included.

  The actuator according to claim 4 is the actuator according to claim 3, wherein each of the first object and the second object is a lens.

  The actuator according to claim 5 is the actuator according to any one of claims 1 to 4, further comprising an outer yoke disposed between the permanent magnet and the coil portion of the second movable coil. .

  In the actuator according to the first aspect, when the first movable coil is energized, the first movable coil moves in the axial direction based on the current flowing through the first movable coil and the magnetic field generated inside the permanent magnet. Further, when the second movable coil is energized, the second movable coil moves in a direction substantially perpendicular to the axial direction based on the current flowing through the coil portion of the second movable coil and the magnetic field generated outside the permanent magnet. Therefore, by controlling the magnitude and direction of the current flowing through the first moving coil and the second moving coil, the first moving coil can be moved in the axial direction, and the second moving coil can be moved in the moving direction of the first moving coil. The actuator can move in a substantially orthogonal direction, and the actuator can be driven in at least two axial directions. Further, since the same permanent magnet can be used for both the movement of the first moving coil and the movement of the second moving coil, the number of parts of the actuator can be reduced and the actuator can be made smaller.

  In the actuator according to claim 2, when the two second movable coils are energized, each second movable coil is moved in the axial direction based on a current flowing through each coil portion and a magnetic field generated outside the permanent magnet. Electromagnetic forces are received in directions that are substantially orthogonal and differ from each other by approximately 90 degrees. Therefore, the first movable coil can be moved in the axial direction by controlling the magnitude and direction of the current flowing through the first movable coil and the two second movable coils, and each second movable coil can be moved to the first movable coil. The actuator can be moved in a direction substantially orthogonal to the moving direction of the coil and substantially orthogonal to each other. As a result, the actuator can be driven in three axial directions.

  In the actuator according to the third aspect, the first object moves in the axial direction together with the first moving coil, and the second object moves in the direction of the resultant electromagnetic force received by each of the two second moving coils.

  The actuator according to claim 4 is configured as a lens driving actuator, and can be focused by moving the lens as the first object in the axial direction, and the lens as the second object is in a direction substantially orthogonal to the axial direction. The optical axis can be corrected by moving the lens to.

  In the actuator according to claim 5, by further providing the outer yoke, a magnetic path is formed with the inner yoke, so that the magnetic field generated inside the permanent magnet can be further increased, and the axial direction of the first movable coil The driving force can be increased.

  According to the present invention, the lens or the like can be moved in the axial direction and in a direction substantially orthogonal thereto without increasing the size of the actuator.

Embodiments of the present invention will be described below with reference to the drawings.
1 to 4, an actuator 10 according to an embodiment of the present invention is configured as a lens driving actuator and includes a yoke 12. The yoke 12 includes a hollow cylindrical inner yoke 14 and four square plate-shaped outer yokes 16 standing on the outer four sides of the inner yoke 14 so as to surround the inner yoke 14 at a predetermined interval. The inner yoke 14 and each outer yoke 16 are connected at one end in the axial direction.

  A hollow cylindrical first movable coil 18 is fitted on the outer side of the inner yoke 14 so as to be movable in the axial direction (Z direction). A square plate-like permanent magnet 20 is provided on the inner surface of each outer yoke 16 and on the outer side of the first movable coil 18, and the outer magnet 16 forms a magnetic path with the outer yoke 16 and the inner yoke 14. 16 and the inner yoke 14 are magnetically coupled. In this embodiment, the polarity of the permanent magnet 20 is set to N pole on the inside and S pole on the outside. Therefore, a magnetic field is generated inside the permanent magnet 20 in a direction substantially perpendicular to the axial direction of the first movable coil 18 as indicated by the arrow A1. A magnetic field is generated on the outer side of the permanent magnet 20 through the outer yoke 16 in a direction substantially perpendicular to the axial direction of the first movable coil 18 as indicated by an arrow A2 (see FIG. 5).

  Since the main magnetic field is formed between the permanent magnet 20 and the inner yoke 14, the magnetic field strength indicated by the arrow A2 is smaller than the magnetic field strength indicated by the arrow A1. However, the driving force required to move the optical axis correction lens 30 in the direction substantially orthogonal to the axial direction is smaller than the driving force required to move the main lens 28 in the axial direction for focusing. There is no problem because it is very small.

  In addition, second movable coils (XY coils) 22a to 22d are provided so as to fit in four corners formed by adjacent permanent magnets 20, respectively. The second movable coil 22a is formed so as to expand in one direction, and has coil portions 23a facing each other. The second movable coil 22 a is disposed such that each coil portion 23 a extends in the axial direction of the first movable coil 18 and is located outside each outer yoke 16. The second movable coils 22b, 22c, and 22d are configured in the same manner as the second movable coil 22a, and have coil portions 23b, 23c, and 23d that face each other. The second movable coils 22b, 22c and 22d are arranged such that the coil portions 23b, 23c and 23d extend in the axial direction of the first movable coil 18 and are located outside the outer yoke 16.

  Further, a hollow cylindrical lens hood 24 is disposed in the inner yoke 14, and the lens hood 24 is connected to the first movable coil 18 by a connecting member 26. A main lens 28 is attached in the lens hood 24. Therefore, as the first movable coil 18 moves in the axial direction, the lens hood 24 and the main lens 28 can move in the axial direction.

  Further, an optical axis correction lens 30 is provided in front of the main lens 28 (upward in FIG. 2), and the optical axis correction lens 30 is connected to the four second movable coils 22 a to 22 d by a connecting member 32. . Therefore, as the second movable coils 22a to 22d move in the direction (XY direction) substantially orthogonal to the axial direction of the first movable coil 18, the optical axis correction lens 30 is moved to the first movable coil. It can move in one direction substantially perpendicular to the 18 axial directions.

  In such an actuator 10, an inward magnetic field substantially perpendicular to the axial direction of the first movable coil 18 as indicated by an arrow A <b> 1 is generated inside the permanent magnet 20, and the first movable coil is in that state. When energizing 18, the first movable coil 18 moves in the axial direction (indicated by arrow B in FIG. 2) based on the current flowing through the first movable coil 18 and the magnetic field generated inside the permanent magnet 20. Accordingly, the main lens 28 also moves in the axial direction and can be focused.

  For example, referring to FIG. 1, when a current is passed through the first movable coil 18 in a counterclockwise direction, an electromagnetic force acts on the first movable coil 18 in a direction that protrudes from the paper surface (upward in FIG. 2). The coil 18 moves in that direction. On the other hand, when a current is passed through the first movable coil 18 in the clockwise direction, an electromagnetic force acts on the first movable coil 18 in the direction of pushing into the paper surface (downward in FIG. 2), and the first movable coil 18 moves in that direction. . The main lens 28 moves together with the first movable coil 18.

  Further, an outward magnetic field substantially perpendicular to the axial direction of the first movable coil 18 as indicated by an arrow A2 (see FIG. 5) is generated outside the permanent magnet 20, and the second movable coil is generated in this state. When energizing at least one of 22a to 22d, the energized second movable coil is based on the current flowing through the coil portion of the energized second movable coil and the magnetic field generated outside the permanent magnet 20. It moves in a direction substantially orthogonal to the axial direction of the first movable coil 18. Accordingly, the optical axis correction lens 30 also moves in a direction substantially orthogonal to the axial direction, and the optical axis can be corrected. In order to increase the magnetic flux generated outside the permanent magnet 20, it is preferable to reduce the thickness of the outer yoke 16.

  For example, the case where an electric current is passed through the four second movable coils 22a to 22d in the direction shown in FIG. 5 will be described. Electromagnetic forces are generated in the directions indicated by arrows C1 and C2 in the two coil portions 23a of the second movable coil 22a, respectively, and the directions indicated by arrows C3 and C4 in the two coil portions 23b of the second movable coil 22b, respectively. Electromagnetic force is generated, electromagnetic force is generated in the direction indicated by arrows C5 and C6, respectively, in the two coil portions 23c of the second movable coil 22c, and arrow C7 is respectively generated in the two coil portions 23d of the second movable coil 22d. And electromagnetic force is generated in the direction indicated by C8. Therefore, electromagnetic forces Ca, Cb, Cc, and Cd that are resultant forces are generated in the second movable coils 22a, 22b, 22c, and 22d, respectively. As can be seen from FIG. 5, the directions of the electromagnetic forces Ca and Cb differ by approximately 90 degrees. The same applies to the electromagnetic forces Cb and Cc, the electromagnetic forces Cc and Cd, and the electromagnetic forces Cd and Ca.

  In this example, a leftward electromagnetic force (in FIG. 5) is generated as a resultant force of the electromagnetic forces Ca to Cd generated in the second movable coils 22a to 22d, and the optical axis correction lens 30 moves leftward.

  Therefore, the main lens 28 can be moved in the axial direction of the first movable coil 18 by controlling the magnitude and direction of the current flowing through the first movable coil 18. Further, by controlling the magnitude and direction of the current flowing through the second movable coils 22a to 22d, the optical axis correcting lens 30 can be moved in an arbitrary direction substantially orthogonal to the axial direction. As a result, the actuator 10 can be driven in three axial directions.

  Further, since the same permanent magnet 20 can be used for moving the main lens 28 in the axial direction and for moving the optical axis correcting lens 30 in a direction substantially orthogonal to the axial direction, the number of parts of the actuator 10 can be reduced. The number of actuators 10 can be reduced, and the cost can be reduced.

  Further, by providing the outer yoke 16, the strength of the magnetic field generated inside the permanent magnet 20 can be further improved, and the driving force in the axial direction of the main lens 28 can be increased.

  On the other hand, the strength of the magnetic field generated outside the outer yoke 16 decreases. However, since the electromagnetic force generated in each of the second movable coils 22a to 22d can be adjusted by the amount of current flowing through the second movable coils 22a to 22d, the original purpose of the present invention is not impaired.

  Two adjacent second movable coils 22a and 22b may be used as the second movable coil as in the actuator 10a shown in FIG. Other configurations are the same as those of the actuator 10 shown in FIG.

  In the actuator 10a, when a current as shown in FIG. 6 is passed through the coil portions 23a and 23b of the second movable coils 22a and 22b, the two coil portions 23a of the second movable coil 22a are respectively indicated by arrows C1 and C2. Electromagnetic force is generated in the direction shown, and electromagnetic force is generated in the directions indicated by arrows C3 and C4 in the two coil portions 23b of the second movable coil 22b. In this example, a leftward electromagnetic force (in FIG. 6) is generated as a resultant force of the electromagnetic force generated in each of the second movable coils 22a and 22b, and the optical axis correction lens 30 moves to the left.

  Also in the actuator 10 a, the main lens 28 can be moved in the axial direction of the first movable coil 18 by controlling the magnitude and direction of the current flowing through the first movable coil 18. Further, by controlling the magnitude and direction of the current flowing through the second movable coils 22a and 22b, the optical axis correcting lens 30 can be moved in any direction substantially orthogonal to the axial direction.

  In the actuator 10a, only one second movable coil 22a may be used as the second movable coil. In this case, the optical axis correcting lens 30 interlocked with the second movable coil 22 a can be moved in a uniaxial direction substantially orthogonal to the axial direction of the first movable coil 18. Therefore, this actuator can be driven in two axial directions.

Furthermore, an actuator 10b according to another embodiment of the present invention will be described with reference to FIG.
The actuator 10 b includes a yoke 33.

  The yoke 33 includes a hollow rectangular tube-shaped inner yoke 34 and four rectangular plate-shaped outer yokes 16 standing on the outer four sides of the inner yoke 34 so as to surround the inner yoke 34 at a predetermined interval. In addition, the inner yoke 34 and each outer yoke 16 are connected on one end side in the axial direction.

  A hollow rectangular tube-shaped first movable coil 36 is fitted to the outside of the inner yoke 34 so as to be movable in the axial direction (Z direction). The lens hood 24 that holds the main lens 28 and the first movable coil 36 are connected to each other. It is connected by a connecting member. Other configurations are the same as those of the actuator 10 shown in FIG.

  Such an actuator 10b is preferable because it can increase the coil length of the first moving coil and the distance between the first moving coil and the permanent magnet 20 is shorter than that of the actuator 10.

An actuator 10c according to another embodiment of the present invention will be described with reference to FIG.
The actuator 10 c includes a yoke 38.

  The yoke 38 includes a hollow cylindrical inner yoke 14 and a cylindrical outer yoke 40 provided outside the inner yoke 14 and coaxially with the inner yoke 14 at a predetermined interval. 40 is connected to one end in the axial direction.

  Four permanent magnets 42 having an arc-shaped cross section are provided on the inner surface of the outer yoke 40 and on the outer side of the first movable coil 18, thereby forming an annular permanent magnet. The permanent magnet 42 is magnetically coupled to the outer yoke 40 and the inner yoke 14.

  Further, four second movable coils 44 a to 44 d are arranged at equal intervals on the outer side of the outer yoke 40. The second movable coil 44a is formed in a circular arc shape in plan view, and has coil portions 46a facing each other. The coil portion 46 a extends in the axial direction of the first movable coil 18 and is located outside the outer yoke 40. The second movable coils 44b, 44c, and 44d are also configured in the same manner as the second movable coil 44a, and have coil portions 46b, 46c, and 46d that face each other. The coil portions 46 b, 46 c and 46 d extend in the axial direction of the first movable coil 18 and are located outside the outer yoke 40. An optical axis correcting lens is connected to the four second movable coils 44a to 44d by a connecting member. Other configurations are the same as those of the actuator 10 shown in FIG.

  Such an actuator 10c is preferable because the outer shape is cylindrical, so that space can be saved as compared with the rectangular actuator 10, and the distance between the first movable coil and the permanent magnet 20 becomes shorter.

Moreover, with reference to FIG. 9, an actuator 10d according to still another embodiment of the present invention will be described.
The actuator 10d uses second movable coils 48a to 48d instead of the second movable coils 44a to 44d of the actuator 10c shown in FIG.
Each of the second movable coils 48 a to 48 d is formed in a substantially linear shape in plan view, and is provided so as to be fitted to the permanent magnet 42.

  The second movable coil 48a has coil portions 50a facing each other. The second movable coil 48 a is disposed such that the coil portion 50 a extends in the axial direction of the first movable coil 18 and is located outside the outer yoke 40. The second movable coils 48b, 48c, and 48d are configured in the same manner as the second movable coil 48a, and have coil portions 50b, 50c, and 50d that face each other. The second movable coils 48b, 48c and 48d are arranged such that the coil portions 50b, 50c and 50d extend in the axial direction of the first movable coil 18 and are located outside the outer yoke 40, respectively. Further, an optical axis correcting lens is connected to the four second movable coils 48a to 48d by a connecting member. Other configurations are the same as those of the actuator 10c shown in FIG.

  Such an actuator 10d makes it easier to manufacture the second movable coil than the actuator 10c.

  Note that the number of second movable coils may be one or two for the actuators 10b to 10d shown in FIGS.

  In each of the actuators described above, all the movable coils included in the actuator may be connected to one lens so that the lens can be moved in three axial directions.

  Furthermore, the object driven by this invention is not limited to a lens.

It is DD (refer FIG. 4) sectional drawing which shows one Embodiment of this invention. It is a longitudinal cross-sectional schematic solution figure which shows embodiment of FIG. It is a top view which shows embodiment of FIG. It is a front view which shows embodiment of FIG. It is an illustration figure for demonstrating the effect | action of embodiment of FIG. It is an illustration figure which shows other embodiment of this invention. It is sectional drawing which shows other embodiment of this invention. It is sectional drawing which shows other embodiment of this invention. It is sectional drawing which shows other embodiment of this invention.

Explanation of symbols

10, 10a, 10b, 10c, 10d Actuator 12, 33, 38 Yoke 14, 34 Inner yoke 16, 40 Outer yoke 18, 36 First moving coil 20, 42 Permanent magnet 22a, 22b, 22c, 22d, 44a, 44b, 44c, 44d, 48a, 48b, 48c, 48d Second movable coil 23a, 23b, 23c, 23d, 46a, 46b, 46c, 46d, 50a, 50b, 50c, 50d Coil portion 24 Lens hood 26, 32 Connecting member 28 Main Lens 30 Optical axis correction lens

Claims (5)

Hollow cylindrical inner yoke,
A first movable coil fitted to the outside of the inner yoke so as to be movable in the axial direction;
A permanent magnet disposed outside the first movable coil; and
A coil portion extending parallel to the axial direction of the first movable coil on the outside of the permanent magnet, and including at least one second movable coil provided to be movable in a direction substantially orthogonal to the axial direction;
An actuator in which the permanent magnet generates a magnetic field in a direction substantially orthogonal to the axial direction of the first moving coil, and generates an electromagnetic force in the first moving coil and the second moving coil by the magnetic field.   2. The actuator according to claim 1, comprising two of the second movable coils, wherein the second movable coils are provided such that directions of electromagnetic forces acting on the second movable coils are different from each other by approximately 90 degrees.   3. The actuator according to claim 2, further comprising: a first object provided to be able to be interlocked with the first movable coil; and a second object provided to be able to be interlocked with the two second movable coils.   The actuator according to claim 3, wherein each of the first object and the second object is a lens. The actuator according to any one of claims 1 to 4, further comprising an outer yoke disposed between the permanent magnet and the coil portion of the second movable coil.

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