JP2007072168A - Dual shaft actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dual shaft actuator which is miniaturized, light-weighted and has superior responsiveness. <P>SOLUTION: The actuator comprises a support mechanism 30 which freely rockably supports an object 20 to be controlled; and a magnetic driving mechanism 40A, which is provided with a magnet M and a plurality of coils C1, C2, C3 and C4, and generates electromagnetic force for driving the object 20 to be controlled. The magnetic drive mechanism 40A is constituted, by providing magnetic flux distributing parts (47a and 46 or the like) which divide a magnetic flux B generated by the magnet M and makes the divided magnetic fluxes link with the electric currents flowing in the respective coils C1, C2, C3 and C4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a biaxial actuator that adjusts an incident angle of reference light to be incident on an optical recording medium by setting a reflection mirror to a desired tilt angle.

  As a method for recording or reproducing a two-dimensional digital signal in a multiplexed manner on a holographic recording medium, a method in which the incident angle or wavelength of reference light incident on the recording medium is changed is generally used.

As a conventional means for adjusting the incident angle of such a light beam (reference light), a galvanometer mirror as an actuator is representative (for example, Patent Document 1).
Japanese Patent Laid-Open No. 2002-169122 (FIGS. 1 to 6)

  However, the galvanometer mirror described in Patent Document 1 is based on a configuration in which the magnets are arranged at symmetrical positions. For this reason, two magnets are required, and there is a problem that it is difficult to reduce the weight of the galvano mirror as a whole and to reduce the cost due to the reduction in the number of parts.

  In the holography apparatus, since the recording capacity per recording position on the holographic recording medium is large, it is desired to shorten the reading time as much as possible. For this purpose, it is particularly necessary to shorten the time (response time) required from setting the read data to setting the incident angle of the reference light to a desired angle, that is, the time required for adjusting the mirror angle. However, since the galvanometer mirror of the above-mentioned Patent Document 1 is configured to include a total of six (one side surface × 2 pieces) electromagnetic coils on both side surfaces of the movable portion that holds and swings the mirror, the movable portion Is relatively heavy. For this reason, there is a problem that it takes a certain amount of time from when the read data is specified until the movable part actually starts to move, and it is difficult to adjust the angle of the mirror at high speed (less responsiveness).

  In this regard, if a large driving force can be obtained from the magnet, the responsiveness can be improved. For this purpose, a heavier and larger magnet is required, so that a reduction in size and weight is realized. It will be difficult.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a biaxial actuator that can be reduced in size and weight and has excellent responsiveness.

  Since the present invention can reduce the number of magnets and coils, the number of parts can be reduced and the cost can be reduced.

  Moreover, since it can be reduced in size or weight, it can be set as the actuator excellent in responsiveness.

The present invention includes a support mechanism that swingably supports a control target, and a magnetic drive mechanism that includes a magnet and a plurality of coils and generates an electromagnetic force that drives the control target.
The magnetic drive mechanism is provided with a magnetic flux distribution unit that divides the magnetic flux generated by the magnet and links the current to the coils.

  In the actuator of the present invention, the magnetic flux generated by one magnet can be divided and guided to a plurality of coils. Therefore, since the number of magnets can be minimized (one), the actuator can be reduced in weight and the cost can be reduced due to the reduction in the number of parts. Moreover, even if the number of magnets is one, a plurality of magnetic drive units can be configured.

Further, according to the present invention, when the movable axis that supports the object to be controlled and the third axis that is perpendicular to the first and second axes orthogonal to each other are used as the reference axis, the movable axis is defined with respect to the reference axis. A support mechanism that swingably supports, and a magnetic drive mechanism that has a magnetic circuit composed of at least a magnet and a coil and tilts the movable shaft from a posture that matches the reference axis to a posture that tilts.
A first magnetic drive unit including a pair of magnetic circuits disposed at positions symmetrical with respect to the reference axis; and the reference axis is orthogonal to the first magnetic drive unit. A second magnetic drive unit composed of a pair of magnetic circuits arranged at positions that are axially symmetric with respect to each other, and each coil that forms the first and second magnetic drive units by dividing the magnetic flux generated by the magnet And a magnetic flux distribution section interlinked with the current flowing in the circuit.

  In the present invention, since the magnetic flux generated by one magnet can be divided and guided to the coil forming the first magnetic drive unit and the coil forming the second magnetic drive unit, the size and weight are reduced. A biaxial actuator can be provided.

  In the above, the magnetic flux distribution section includes a first yoke including a main body portion to which one pole of the magnet is fixed and an extension portion continuous to the outside of the main body portion, and a main body to which the other pole is fixed. And a second yoke including a plurality of arm portions that are included in a plane that forms the main body portion and that are formed so as to protrude in two axial directions orthogonal to each other, and the extension portion and the arm portion are Preferably, a coil is provided in the opposing gap, and the arm is preferably disposed within the coil with a predetermined movable margin.

  Alternatively, the magnetic flux distribution section includes a first yoke having a main body portion to which one pole of the magnet is fixed and a side wall portion that is continuous with the main body portion and is disposed so as to surround a side surface of the magnet; A second arm provided inside the first yoke and having a main body portion to which the other pole of the magnet is fixed and extending in two axial directions perpendicular to each other and facing the side wall portion; A yoke is provided, and a coil is provided in a gap where the side wall portion and the arm portion face each other, and the arm portion is preferably disposed within the coil with a predetermined movable margin. .

  With the above means, even if there is only one magnet, an electromagnetic force can be generated for each of a plurality of magnetic drive units (coils). Therefore, by combining these, a large electromagnetic force can be obtained, and it becomes possible to provide an actuator that is lightweight and excellent in responsiveness. In addition, since a plurality of magnetic drive units can be configured, it is possible to swing the controlled object about two axes.

  It is preferable that the first yoke and the second yoke are formed by sheet metal working by cutting and bending a plate-like soft magnetic material.

  In the above means, the first and second yokes can be easily and easily formed by sheet metal processing, so that it is possible to reduce the manufacturing cost and provide an inexpensive actuator.

  It is preferable that the magnetic flux distribution unit is provided on the movable shaft side, and the coil is provided on the fixed member side that supports the support mechanism.

  The above means can provide an MM (moving magnet) type actuator that does not require wiring to the movable shaft side, so that the assembly of the actuator can be facilitated.

  The coil is preferably provided on the movable shaft side, and the magnetic flux distribution part is preferably provided on the fixed member.

  According to the above means, an MC (moving coil) type actuator capable of reducing the weight of the movable shaft side can be provided, so that the actuator can be made more responsive.

Furthermore, in the above, the direction of the main magnetic flux passing through the gap is set perpendicular to the third axis,
The one magnetic circuit forming the pair of magnetic circuits and the electromagnetic force generated in the other magnetic circuit act in the same direction, and the support center point of the support mechanism is the rotation center of the electromagnetic force. Components acting in the tangential direction of the circle can also be in the same direction.

Alternatively, the direction of the main magnetic flux passing through the gap is set perpendicular to the third axis,
The one magnetic circuit forming the pair of magnetic circuits and the electromagnetic force generated in the other magnetic circuit act in the same direction, and the support center point of the support mechanism is the rotation center of the electromagnetic force. Components acting in the tangential direction of the circle can also be in the same direction.

  In the above configuration, the electromagnetic force generated in one magnetic circuit and the electromagnetic force generated in the other magnetic circuit can be combined and efficiently converted into a rotational force. For this reason, it can be set as the actuator excellent in responsiveness.

  1 is a perspective view showing a galvanometer mirror as an embodiment of a biaxial actuator according to the present invention, FIG. 2 is an exploded perspective view of FIG. 1, and FIG. 3 shows a coil and a bobbin constituting a part of a magnetic drive mechanism. 4A is a plan view, FIG. 4B is a cross-sectional view taken along line B-B in FIG. 4A, and FIG. 4 is a perspective view showing the magnetism generator from a direction different from FIG.

  The actuator 10A shown in the present embodiment constitutes a galvanometer mirror, and is roughly composed of three members, that is, a controlled object 20, a support mechanism 30, and a magnetic drive mechanism 40A as shown in FIGS. Yes. Hereinafter, each mechanism will be described in detail.

  The control object 20 is a reflection mirror 21 supported by a mirror support portion 22. The reflection mirror 21 is, for example, a total reflection type mirror, and emits light incident at a predetermined angle from the Z1 side toward the Z2 direction in the drawing. Further, by changing the tilt angle of the reflection mirror 21, the direction of emission of the reflected light can be adjusted.

  The mirror support portion 22 includes a support plate 22a having an L-shaped cross section, and a movable shaft 22b protruding in the Z2 direction is provided on the back surface (surface on the Z2 side in the drawing). In the present embodiment, the movable shaft 22b is set so that its extending direction (Z direction) has a predetermined angle other than 90 degrees with respect to the mirror surface 21a of the reflecting mirror 21. That is, the reflection mirror 21 is fixed in a state where the mirror surface 21a has a predetermined inclination angle with respect to the direction in which the movable shaft 22b extends (Z direction) in advance.

  The reflection mirror 21 is fixed through means such as adhesive or screwing with the back surface 21b placed on the support plate 22a. On the surface of the movable shaft 22b, a pair of first concave portions 22c and 22c are formed that are curved in a concave shape with a predetermined curvature. The first recesses 22c, 22c are formed on the surface of the movable shaft 22b and at symmetrical positions (positions that differ by 180 degrees).

  The support mechanism 30 includes a fixed base 31, a movable ring 32, and a plurality of small spheres 33. The fixed base 31 is a plate-like member formed with a circular opening 31a that penetrates through the central portion, and fixed portions 31b and 31b that are formed in a protruding shape are provided at both ends in the X direction. Yes.

  The movable ring 32 is formed of a ring-shaped member having an outer diameter smaller than the inner diameter of the opening 31a and an inner diameter larger than the outer diameter of the movable shaft 22b of the mirror support portion 22. ing.

  The movable shaft 22b is inserted into the movable ring 32, and is located symmetrically between the outer surface of the movable shaft 22b and the inner peripheral surface of the movable ring 32 (a position different by 180 degrees). Are provided with small spheres 33, 33 which rotate freely. For this reason, the movable shaft 22b and the movable ring 32 are relatively swung in the illustrated α1 and α2 directions around the virtual axis P1-P2 (first axis) connecting the small sphere 33 and the small sphere 33. It is held in a movable relationship.

  Further, it is freely located between the outer peripheral surface of the movable ring 32 and the inner surface of the opening 31a of the fixed base 31 and at a position different by 90 degrees along the circumferential direction from the position where the small balls 33 and 33 are disposed. Are provided with rotating spheres 34, 34. For this reason, the movable ring 32 and the fixed base 31 swing relative to the directions of the virtual axes Q1-Q2 (second axes) connecting the small spheres 34 and the small spheres 34 in the directions β1 and β2. It is held freely. The intersection of the rotation axis of the movable shaft 22b (virtual axis P1-P2 (first axis)) and the rotation axis of the movable ring 32 (virtual axis Q1-Q2 (second axis)) is the center of rotation (support). The support center point O) of the mechanism.

  That is, the movable shaft 22b is held so as to be swingable with respect to two axes of the virtual axis P1-P2 (first axis) and the virtual axis Q1-Q2 (second axis) orthogonal thereto. . Therefore, the movable shaft 22b can be tilted freely over a range of 360 degrees with respect to the Z-axis (third axis; reference axis) passing through the support center point O. .

  The magnetic drive mechanism 40A mainly includes a fixing member 41, a coil, and a magnetic generator 45A.

  As shown in FIG. 2, the fixing member 41 is formed of a substantially U-shaped metal plate or the like, and has a bottom surface 41A and side walls 41B and 41B extending continuously in the Z1 direction in the figure at both ends. Is provided. In addition, elongated holes 41a and 41a that penetrate in the X direction and extend in the Y direction are formed at the tips of the side wall portions 41B and 41B. The long holes 41a and 41a can be fitted with fixing portions 31b and 31b formed in the fixing base 31. That is, the fixed base 31 is supported by the fixed member 41.

  As shown in FIGS. 2 and 3, the magnetic drive mechanism 40 </ b> A has a substantially cross shape in plan and has a bobbin 43 formed of a resin material or the like. The bobbin 43 has a square base portion 43A provided at the center, and cylindrical winding portions 44A, 44B, 44C and 44D that protrude in four directions from the outer peripheral surface of the base portion 43A. Communication portions 43a, 43a, 43a, and 43a are formed on the outer peripheral surface of the base portion 43A so as to extend from the inside of the base portion 43A to the winding portions 44A, 44B, 44C, and 44D. Further, flange portions 44a, 44a, 44a, and 44a are integrally formed at the ends of the winding portions 44A, 44B, 44C, and 44D so as to spread in a direction perpendicular to the extending direction of each winding portion. As will be described later, four coils C1, C2, C3 and C4 are formed on the outer periphery of each of the winding portions 44A, 44B, 44C and 44D and between the outer peripheral surface of the base portion 43A and the flange portion 44a. It is like that. Alternatively, for example, the base portion 43A and the winding portions 44A, 44B, 44C, and 44D may be configured separately.

  The bobbin 43 having the four coils C1, C2, C3, and C4 in four directions as described above is fixed to the bottom surface 41A of the fixing member 41.

  As shown in FIGS. 2 and 4, the magnetism generating portion 45 </ b> A includes a lower yoke (first yoke) 46, a magnet M, and an upper yoke (second yoke) 47. The lower yoke 46 is formed of a metal plate made of a soft magnetic material such as a galvanized steel plate (SPCC), and is formed as an octagonal metal plate wider than the bottom area of the magnet M. The end surface of the movable shaft 22b is fixed to the surface of the lower yoke 46 on the Z1 side.

  The magnet M shown in the present embodiment has a square shape, and is fixed to the central portion on the surface of the lower yoke 46 on the Z2 side in the drawing. The magnet M is magnetized in the surface direction such that the Z1 side is an S pole and the Z2 side is an N pole.

  As shown in FIG. 4, the upper yoke 47 is also formed of a metal plate made of the same soft magnetic material as described above, and has a square main body portion 47A having substantially the same area as the magnet M, and the main body portion 47A. It has four arm portions 47a, 47a, 47a, 47a extending from four side surfaces in the illustrated P1-P2 direction and Q1-Q2 direction. The tips of the four arm portions 47a, 47a, 47a, 47a are bent in a direction close to the lower yoke 46 (Z1 direction), and the lower yoke 46 and the tip portions of the arm portions 47a, 47a, 47a, 47a. Is set so that the facing distance (gap length) is shortened.

  The upper yoke 47 is formed by sheet metal processing. For example, a predetermined die is used to cut (punching) the square main body portion 47A from the metal plate and the upper yoke 47 having the arm portions 47a, 47a, 47a, 47a around it. Then, only the tip portions of the arm portions 47a, 47a, 47a, 47a can be formed by bending with a pressure press.

  In this way, the opposing distance (gap length) between each arm 47a and the lower yoke 46 is narrower at the tip than at the base end on the main body 47A side. Therefore, the magnetic flux density between the tip of each arm 47a and the lower yoke 46 (in the gap G) is compared with the magnetic flux density between the proximal end of each arm 47a and the lower yoke 46. Big.

  For this reason, even if the magnet M has a low strength (maximum energy product), the magnetic flux divided from the magnet M can be efficiently guided into the gap G. Alternatively, the magnet M having a high maximum energy product such as a neodymium magnet can be made smaller or thinner. Therefore, since the magnetism generating portion 45A can be reduced in weight, it is possible to obtain an actuator with better responsiveness.

  The upper yoke 47 is fixed via an adhesive provided between the lower surface (Z1 side surface) of the main body 47A and the upper surface (Z2 side surface) of the magnet M.

  The upper yoke 47 is disposed in the bobbin 43. That is, the main body portion 47A of the upper yoke 47 is provided in the base portion 43A of the bobbin 43, and the arm portions 47a are positioned in the winding portions 44A, 44B, 44C, and 44D through the communication portions 43a. Each is arranged. Then, in the state where the respective arm portions 47a of the upper yoke 47 are arranged in the winding portions 44A, 44B, 44C, and 44D as described above, the coated conductors are provided around the winding portions 44A, 44B, 44C, and 44D. Are wound to form four coils C1, C2, C3, and C4.

  The base portion 43A and the winding portions 44A, 44B, 44C and 44D constituting the bobbin 43 may be configured separately. In this case, the coils C1, C2, C3, and C4 are formed by winding a wire around the winding portions 44A, 44B, 44C, and 44D in advance, and the magnet M and the upper yoke 47 are placed in the base portion 43A. Each winding portion provided with the coils C1, C2, C3, C4 so as to surround the arms 47a projecting to the outside of the base portion 43A via the communication portions 43a. By fixing 44A, 44B, 44C, and 44D to the four outer peripheral surfaces of the base portion 43A, the bobbin 43 that integrally includes four coils C1, C2, C3, and C4 can be obtained.

The operation of the actuator will be described.
FIG. 5 is a cross-sectional view of the magnetic drive unit for explaining the operation of the actuator. As shown in FIG. 5, the tip of each arm portion 47a and the lower yoke 46 are arranged so as to face each other across a certain gap G, and each of the four coils C1, A part of C2, C3 and C4 is arranged.

  In the magnetism generating portion 45A, the magnetic flux B generated from the N pole of the magnet M advances in the outer peripheral direction away from the center in the main body portion 47A in the upper yoke 47 and is guided to each arm portion 47a. The magnetic flux B escapes to the outside from the lower surface (the surface on the Z1 side) of the tip portion of each arm portion 47a, and enters the lower yoke 46 through the gap G provided at a position facing it. Further, the magnetic flux B forms a magnetic circuit (magnetic path) in which the magnetic flux B travels in the center direction in the lower yoke 46 and reaches the south pole of the magnet M. When the magnetic flux B passes through the gap G, the magnetic flux B and the current I flowing through the coils C1, C2, C3, C4 are vertically linked.

  Here, in the magnetic drive mechanism 40A, the coil C1 and the coil C2 arranged along the virtual line P1-P2 form a first magnetic drive unit, and are arranged along the virtual line Q1-Q2. The coil C3 and the coil C4 form a second magnetic drive unit.

  Assuming that a clockwise current as viewed from the outside indicated by an arrow A1 in FIG. 5 flows through the coil C1 on the P1 side forming the first magnetic drive unit, Fleming's left-hand rule follows the coil C1. Electromagnetic force F1 is generated. At the same time, when a current in the counterclockwise direction as viewed from the outside indicated by an arrow A2 in FIG. 5 flows in the coil C2 on the P2 side that forms the first magnetic drive unit, an electromagnetic force F2 is generated in the coil C2. To do. The electromagnetic force F1 and the electromagnetic force F2 are equal in magnitude and direction, and are generated at the same position from the support center point O. The electromagnetic force F1 and the electromagnetic force F2 can be divided into a radial component and a tangential component F1t, F2t of a predetermined circle centered on the support center point O, respectively. F1t and F2t contribute as forces that cause clockwise rotation in FIG. Therefore, the magnetic generator 45A can be swung clockwise (β1 direction) in FIG. For this reason, from the state in which the movable shaft 22b provided perpendicularly to the lower surface of the lower yoke 46 forming the magnetism generating portion 45A coincides with the Z-axis (third axis), the virtual axes P1-P2 (first It can be tilted in the P2 direction along the (axis) line. Therefore, the mirror surface 21a of the reflecting mirror 21 constituting the control target 20 provided at the tip of the movable shaft 22b can be tilted in the P2 direction.

  When the directions of the currents flowing through the coils C1 and C2 are changed, the magnetism generating part 45A is swung in the counterclockwise direction (β2 direction). It can be tilted in the P1 direction along the axis P1-P2 (first axis). Therefore, the mirror surface 21a of the reflection mirror 21 constituting the control target 20 can be tilted in the P1 direction along the virtual axis P1-P2 (first axis) line.

  The above relationship is the same between the Q1 side coil C3 and the Q2 side coil C4 forming the second magnetic drive unit. That is, by changing the direction of the current flowing through the coil C3 and the coil C4, the movable shaft 22b is moved from the state coincident with the Z axis in the direction P1 or P2 along the virtual axis Q1-Q2 (second axis). Can be tilted.

  Therefore, by setting the direction of the current flowing through the coils C1 and C2 forming the first magnetic driving unit and the C3 and C4 forming the second magnetic driving unit to a predetermined direction, the movable shaft 22b is set to the Z axis. To the P1 or P2 direction along the virtual axis P1-P2 (first axis) line and the P1 or P2 direction along the virtual axis Q1-Q2 (second axis) line, that is, 360 degrees. It can be tilted freely over a range.

  In the actuator, the coil C1, the arm portion 47a of the upper yoke 47 inserted into the coil C1, the magnet M, and the lower yoke 46 form one magnetic circuit, and are inserted into the coil C2 and the coil C2. The arm portion 47a of the upper yoke 47, the magnet M, and the lower yoke 46 form another magnetic circuit. Such a pair of magnetic circuits functions as a first magnetic drive unit that rotates the magnetic generating unit 45A having the upper yoke 47, the magnet M, and the lower yoke 46 in the β1 and β2 directions.

  Further, the coil C3, the arm portion 47a of the upper yoke 47 inserted into the coil C3, the magnet M and the lower yoke 46 form one magnetic circuit, and the coil C4 and the upper yoke 47 inserted into the coil C4. The arm portion 47a, the magnet M, and the lower yoke 46 form another magnetic circuit. Such a pair of magnetic circuits functions as a second magnetic drive unit that rotates the magnetic generating unit 45A having the upper yoke 47, the magnet M, and the lower yoke 46 in the α1 and α2 directions.

  For this reason, by using the first magnetic drive unit and the second magnetic drive unit arranged in a direction perpendicular to the first magnetic drive unit, the movable shaft 22b connected to the magnetism generating unit 45B is moved to the Z-axis (the first axis). Can be tilted from a posture that coincides with the third axis (reference axis). Therefore, it is possible to freely tilt the control object 20, that is, the reflection mirror 21, provided at the other end of the movable shaft 22b in the biaxial direction.

  Further, in the above, each arm portion 47a, 47a, 47a, 47a of the upper yoke 47 (second yoke) and the lower yoke (first yoke) 46 have a magnetic flux generated by one magnet M. In addition to the division, a magnetic flux distribution unit is formed that is distributed to the coils C1 and C2 of the first magnetic drive unit and the C3 and C4 of the second magnetic drive unit located in each gap G.

  6 is an exploded perspective view of an actuator showing a second embodiment of the present invention, FIG. 7 is a perspective view showing an outer yoke, A is a state after cutting, B is a state after pressure pressing, FIG. FIG. 9 is a perspective view showing an inner yoke, A is a state after cutting, B is a state after pressure pressing, and FIG. 9 is a cross-sectional view of a magnetic drive unit of an actuator showing a second embodiment.

  The actuator 10B shown in the second embodiment and the actuator 10A of the first embodiment are mainly different in the configuration of the magnetic drive mechanism, and the configurations of the control target 20 and the support mechanism 30 are the same. Therefore, in the following actuator 10B, it demonstrates centering around the structure of the magnetic drive mechanism which is a different part. The same members as those in the first embodiment will be described with the same reference numerals.

  As shown in FIG. 6, the magnetic drive mechanism 40B constituting the actuator 10B includes a coil, a fixing member 41, a magnetic generator 45B, and the like.

  As shown in FIG. 6, the fixing member 41 is formed of a substantially U-shaped metal plate having a bottom surface 41A and side wall portions 41B and 41B. At the tips of the side walls 41B and 41B, there are formed long holes 41a and 41a for fitting and supporting fixed portions 31b and 31b formed on the fixed base 31 of the support mechanism 30 similar to the above. The support mechanism 30 is fixed to the holes 41a and 41a.

  The bottom surface 41A of the fixing member 41 is provided with four coils C1, C2, C3, and C4 having a cylindrical shape with the opening end directed in the Z direction shown in the drawing. Each of the coils C1, C2, C3, and C4 is formed into a coil shape by, for example, winding a coated wire covered with a heat-sealable resin around the outer periphery of a bobbin (core material) having a predetermined outer dimension a predetermined number of times. The coil is placed in a high temperature environment to melt the resin to fix the wires, and after returning to room temperature, the bobbin is pulled out to form an air core coil. Each of the coils C1, C2, C3, and C4 forming the magnetic drive mechanism 40B is provided at a position where the coils C1 and C2 are axisymmetric with respect to the Z axis, and the coil C3 and the coil C4 are located at a position where the axes are symmetrical. Is provided. The coil C1 and the coil C2, and the coil C3 and the coil C4 are provided at positions that differ by 90 degrees in the circumferential direction (around the Z axis). Also in the magnetic drive mechanism 40B, the coil C1 and the coil C2 arranged along the virtual line P1-P2 form a first magnetic drive unit, and the coil C3 arranged along the virtual line Q1-Q2. And the coil C4 form a second magnetic drive unit. The coil C1 and the coil C2 that form the first magnetic drive unit are connected in series by being formed of a single wire, and the coil C3 and the coil that also form the second magnetic drive unit C4 is connected in series.

  The magnetism generator 45B is mainly composed of three members: an outer yoke (first yoke) 48, a magnet M, and an inner yoke (second yoke) 49.

  The outer yoke 48 and the inner yoke 49 are formed by cutting a metal plate made of a soft magnetic material such as a galvanized steel plate (SPCC), and then subjecting the metal plate to pressing and bending.

  That is, when the metal plate is punched out using a predetermined mold as shown in FIG. 7A, a square main body 48A and four side walls 48a, 48a, 48a, 48a are provided at the four corners of the main body 48A. A flat plate-like outer yoke 48 is formed. Then, the four side wall portions 48a, 48a, 48a, 48a are bent 90 degrees in the same direction with respect to the main body portion 46A by a pressure press, and are also bent in the circumferential direction, whereby a substantially cup as shown in FIG. 8B is obtained. The outer yoke 48 having a shape is completed. At this time, a square-shaped base portion 48b and a circular positioning convex portion 48c that further protrudes from the central portion of the base portion 48b are formed simultaneously on the lower surface (the surface on the Z1 side) of the main body portion 48A. Although the end surface of the movable shaft 22b is fixed to the base portion 48b, the end surface of the movable shaft 22b is fixed by the positioning convex portion 48c so as to pass through the center of the outer yoke 48. It is possible.

  The inner yoke 49 is also formed by punching and cutting the metal plate using a predetermined mold. That is, as shown in FIG. 8A, a flat plate-like inner yoke 49 provided with a square-shaped main body 49A and four arms 49a, 49a, 49a, 49a extending outward from the four corners of the main body 49A. Formed as. Then, the four arm portions 49a, 49a, 49a, 49a are subjected to pressure press processing for bending the main body portion 49A by 90 degrees in the same direction, and the inner yoke 49 as shown in FIG. 9B is completed. To do.

  The inner dimension of the outer yoke 48 is larger than the outer dimension of the inner yoke 49, and the inner yoke 49 can be accommodated inside the outer yoke 48.

  The inner yoke 49 is fixed inside the outer yoke 48 in a state where the magnet M is fixed to the center of the Z1 side surface of the main body 49A. As shown in FIG. 9, in the magnetism generating portion 45 </ b> B, the magnet M is sandwiched between the main body portion 48 </ b> A of the outer yoke 48 and the main body portion 49 </ b> A of the inner yoke 49. Further, a gap G is formed at a portion where the arm portions 49a, 49a, 49a, 49a of the inner yoke 49 and the side wall portions 48a, 48a, 48a, 48a of the outer yoke 48 face each other. A fixing member 41 (see FIG. 6) having four coils C1, C2, C3, and C4 forming the magnetic drive mechanism 40B is disposed opposite to the Z2 side of the magnetism generating unit 45B. The tips of four arms 49a, 49a, 49a, 49a forming the inner yoke 49 are inserted into the four coils C1, C2, C3, C4. That is, a part of each of the coils C1, C2, C3, and C4 is disposed in each gap G, so that a magnetic drive mechanism 40B having a first magnetic drive unit and a second shaft drive unit is formed. Yes.

  In the magnet M, for example, the Z1 side is magnetized to the S pole, and the Z2 side is magnetized to the N pole. In such a magnetism generating portion 45B, the N pole of the magnet M → the main body portion 49A of the inner yoke 49 → the arm portions 49a of the inner yoke 49 → the gaps G → the side wall portions 48a of the outer yoke 48 → the main body of the outer yoke 48. A magnetic circuit (magnetic path) including a path from the part 48A to the S pole of the magnet M is formed.

  At this time, when a current in a predetermined direction is applied to each of the coils C1, C2, C3, and C4 provided in the gap G, an electromagnetic force is generated in accordance with Fleming's left-hand rule as in the first embodiment.

  In the gap G, the direction of the magnetic flux B and the winding direction of the coils C1, C2, C3, C4 are orthogonal to each other. Therefore, as shown in FIG. 9, in the first magnetic drive unit, when a predetermined current I is passed through the coils C1 and C2 connected in series with each other, an electromagnetic force due to the action of the magnetic flux B and the current I is generated. Each can be generated according to the direction of the current I.

  That is, when FIG. 9 is viewed from the direction of the arrow A3, when a current I that is clockwise with respect to the coil C1 and a current I that is counterclockwise with respect to the coil C2 is allowed to flow, The direction of the electromagnetic force F1 ′ acting on C1 is the Z2 direction in the figure, and the direction of the electromagnetic force F2 ′ acting on the coil C2 is the Z1 direction in the figure.

  Since the bobbin 43 having the coils C1 and C2 is fixed to the bottom surface 41A of the fixing member 41, the coils C1 and C2 themselves cannot move. For this reason, as shown in FIG. 9, a force F1 as a reaction of the electromagnetic force F1 'acts on the coil C1 in the Z1 direction via the arm portion 49a of the inner yoke 9, and the coil C2 has an electromagnetic force F2'. As a reaction, the force F2 acts in the Z2 direction via the arm portion 49a of the inner yoke 49.

  That is, forces F1 and F2 that are opposite to each other act on the coil C1 and the coil C2 that form the first magnetic drive unit. The driving force F1a, which is a component of the force F1, and the driving force F2a, which is a component of the force F2, act in the tangential direction of a circle having the same radius L with the support center point O as the center. Therefore, the inner yoke 49 can be rotated in the clockwise direction in FIG. 9 (in the direction of β1 around the virtual axis Q1-Q2 (second axis)). The driving torque T at this time can be expressed as T = F1a · L + F2a · L = 2 · Fa · L (where F1a = F2a = Fa).

  In the actuator described above, the coil C1, the arm portion 49a of the inner yoke 49 inserted into the coil C1, the magnet M, and the outer yoke 48 form one magnetic circuit, and are inserted into the coil C2 and the coil C2. The arm portion 49a of the inner yoke 49, the magnet M, and the outer yoke 48 form another magnetic circuit. Such a pair of magnetic circuits functions as a first magnetic drive unit that rotates the magnetic generator 45B having the inner yoke 49, the magnet M, and the outer yoke 48 in the β1 and β2 directions.

  If the direction of the current I is opposite to that in the above example, the magnetic generator 45B is rotated in the counterclockwise direction (virtual axis Q1-Q2 (second axis) β2 direction) in FIG. It is possible to rotate.

  Thus, when the direction of the current I is changed, the magnetism generating part 45B rotates, so that the clockwise direction (β1 direction) and the counterclockwise direction (β2) with the movable shaft 22b as the rotation center (support center point) O are set. Can be swung in the direction).

  The above relationship is the same in the magnetic circuit including the coil C3 and the coil C4 that form the second magnetic drive unit. That is, by changing the direction of the current I flowing through the coil C3 and the coil C4 that form the second magnetic drive unit, the virtual axis Q1-Q2 (the first axis) having the movable shaft 22b as the rotation center (support center point) O 2 axis), that is, in the α1 direction and the α2 direction in FIG.

  In this case, the coil C3, the arm portion 49a of the inner yoke 49 inserted into the coil C3, the magnet M, and the outer yoke 48 form one magnetic circuit, and are inserted into the coil C4 and the coil C4. The arm portion 49a of the inner yoke 49, the magnet M, and the outer yoke 48 form another magnetic circuit. The pair of magnetic circuits function as a second magnetic drive unit that rotates the magnetism generating unit 45B in the α1 and α2 directions.

  For this reason, by using the first magnetic drive unit and the second magnetic drive unit arranged in a direction perpendicular to the first magnetic drive unit, the movable shaft 22b connected to the magnetism generating unit 45B is moved to the Z-axis (the first axis). Can be tilted from a posture that coincides with the third axis (reference axis). Therefore, it is possible to freely tilt the control object 20, that is, the reflection mirror 21, provided at the other end of the movable shaft 22b in the biaxial direction.

  Also in the second embodiment, each arm portion 49a of the inner yoke 49 (second yoke) and each side wall portion 48a of the outer yoke (first yoke) 48 disposed opposite thereto. The magnetic flux distribution that divides the magnetic flux generated by one magnet M and distributes it to the coils C1 and C2 of the first magnetic drive unit and the C3 and C4 of the second magnetic drive unit located in each gap G. Forming part.

  In the first and second embodiments described above, the magnet generator 45A or 45B is provided on the movable shaft 22b side and the so-called MM (moving magnet) type actuator that swings on the magnet M side has been described. It is not limited, and when the magnetism generating part 45A or 45B is fixed to the bottom surface 41A of the fixed member 41 and the coils C1 to C4 are arranged on the end surface of the movable shaft 22b, a so-called MC (moving coil) in which the coil side swings. Type actuators.

  In the first and second embodiments, the actuator swings in the direction of two axes (virtual axis P1-P2 (first axis) and virtual axis Q1-Q2 (second axis)) with one magnet. Therefore, the number of parts can be reduced as compared with the prior art.

  Further, the weight can be reduced by using one magnet. For this reason, it is possible to improve the responsiveness of an MM (moving magnet) type actuator. In addition, since the number of coils can be reduced, the responsiveness of an MC (moving coil) type actuator can be improved.

  Next, a holography apparatus using any one of the two-axis actuators will be described.

  FIG. 10 is a perspective view showing an outline of the arrangement relationship of each member constituting the holography device, and FIG. 11 is a front view corresponding to the view from the arrow direction of FIG.

  The holography device shown in FIG. 10 is mounted on, for example, an optical recording medium reproducing device. However, the apparatus is not limited to a reproduction-only apparatus, and may be a recording-only apparatus or a recording / reproducing apparatus.

  The holography apparatus is mainly composed of an optical system including a light source 61, a collimating lens 62, a reflection mirror 21, an actuator 10, an aperture filter 64, a photodetector 65, and the like.

  The light source 61 is composed of laser light emitting means such as a vertical cavity surface emitting laser (hereinafter referred to as “VCSEL (Vertical Cavity Surface Emitting Laser)”.

  The collimating lens 62 and the reflection mirror 21 are provided on the optical path of the laser light emitted from the light source 61. The reflection mirror 21 is provided in any one of the actuators 10 and is supported so as to be swingable in two axial directions. The actuator 10 and the reflection mirror 21 constitute a so-called galvanometer mirror.

  The collimator lens 62 is provided between the light source 61 and the reflection mirror 21. The collimator lens 62 converts the laser light (diverging light) L1 incident from the light source 61 into reference light L2 made of parallel light, and the reference light L2 is output toward the reflection mirror 21. It has become.

  The reference light L2 converted into parallel light by the collimator lens 62 is reflected by the reflection mirror 13, and illuminates a predetermined position on the optical recording medium 70 as the reference light L3.

  At this time, the angle of the actuator 10 is adjusted so that the reference light L <b> 2 reflected by the reflection mirror 21 can illuminate a predetermined position on the optical recording medium 70. Such an angle adjustment of the reflection mirror 21 gives the current I having a predetermined direction and magnitude to the four coils C1 to C4 forming the first magnetic drive unit and the second magnetic drive unit as described above. Can be done.

  For this reason, the reference light L3 output from the reflection mirror 13 is reflected by the reflection layer 72 and is output to the outside of the optical recording medium 70 as reproduction light L4.

  The optical recording medium 70 shown in this embodiment is a so-called reflection type recording medium, and has a configuration having a reflective layer 72 below a recording layer 71 capable of recording interference fringes. In the recording layer 71, a plurality of holograms indicating data information are recorded in multiple as interference fringes (checkered two-dimensional dot patterns) with the recording angle changed. For this reason, the reproduction light L4 includes data information by the interference fringes.

  The aperture filter 64 and the photodetector 65 are provided on the optical path of the reproduction light L4 output from the optical recording medium 70. The aperture filter 64 excludes unnecessary light from the reproduction light L4.

  As the light detector 65, for example, a CCD or a CMOS image sensor can be used. When the reproduction light L4 is illuminated by the light detector 65 at a predetermined incident angle θ, the light detector 65 includes the incident angle θ and the reproduction light among a lot of data information included in the reproduction light L4. It is possible to read out only the data information recorded at a position where the relationship between the L4 and the wavelength λ matches a predetermined black conditional expression.

  Then, by driving the actuator 10 and finely adjusting the angle of the reflection mirror 21, the incident angle θ of the reference light L3 incident on the optical recording medium 70 can be changed. Individual data information recorded in multiple layers on the layer 71 can be read out.

  In the above embodiment, a biaxial actuator has been mainly described as an actuator having a magnetic distribution unit. However, it goes without saying that the actuator can be applied to a uniaxial actuator.

  In the support mechanism 30 of each of the above embodiments, the small balls 33 and 34 are used as a mechanism for rotating between the fixed base 31 and the movable ring 32 and between the movable ring 32 and the movable shaft 22b. However, the present invention is not limited to this. For example, instead of the small balls 33 and 34, a rotating pin and a bearing member that supports the rotating pin may be used. Alternatively, the support mechanism 30 is formed as an integral gimbal obtained by pressing a leaf spring, and the movable shaft 22b is tilted in two axial directions by elastically deforming (twisting) the leaf spring. There may be.

The perspective view which shows the galvanometer mirror as embodiment of the biaxial actuator which is this invention, 1 is an exploded perspective view of FIG. The coil and bobbin which comprise a part of magnetic drive mechanism are shown, A is a top view, B is arrow directional cross-sectional view in the BB line of A, The perspective view which shows a magnetism generation part from the direction different from FIG. Sectional drawing of the magnetic drive part for demonstrating operation | movement of an actuator, An exploded perspective view of an actuator showing a second embodiment of the present invention, It is a perspective view which shows an outer yoke, A is a state after cutting, B is a state after pressing, It is a perspective view which shows an inner yoke, A is a state after cutting, B is a state after pressing, Sectional drawing of the magnetic drive part of the actuator which shows 2nd Embodiment, The perspective view which shows the outline of the arrangement | positioning relationship of each member which comprises a holography apparatus, Front view corresponding to the direction of the arrow in FIG.

Explanation of symbols

10, 10A, 10B Biaxial actuator 20 Control target 21 Reflection mirror 22 Mirror support portion 22b Movable shaft 30 Support mechanism 31 Fixed base 32 Movable rings 33, 34 Small balls 40A, 40B Magnetic drive mechanism 41 Fixed member 43 Bobbins 45A, 45B Magnetic generator 46 Lower yoke (first yoke)
47 Upper yoke (second yoke)
47a Arm 48 Outer yoke (first yoke)
48a Side wall 49 Inner yoke (second yoke)
49a Arm C1, C2, C3, C4 Coil M Magnet O Rotation center (support center point of support mechanism)
P1-P2 virtual axis (first axis)
Q1-Q2 virtual axis (second axis)

Claims (9)

A support mechanism for swingably supporting the control target, and a magnetic drive mechanism including a magnet and a plurality of coils and generating an electromagnetic force for driving the control target,
2. The actuator according to claim 1, wherein the magnetic drive mechanism is provided with a magnetic flux distribution unit that divides the magnetic flux generated by the magnet and links the current to the coils. When the movable axis that supports the controlled object and the third axis that is perpendicular to the first and second axes orthogonal to each other are used as the reference axis, the movable axis is supported so as to be swingable with respect to the reference axis. And a magnetic drive mechanism that has a magnetic circuit composed of at least a magnet and a coil and tilts the movable shaft from a posture that matches the reference axis to a posture that tilts.
A first magnetic drive unit including a pair of magnetic circuits disposed at positions symmetrical with respect to the reference axis; and the reference axis is orthogonal to the first magnetic drive unit. A second magnetic drive unit composed of a pair of magnetic circuits arranged at positions that are axially symmetric with respect to each other, and each coil that forms the first and second magnetic drive units by dividing the magnetic flux generated by the magnet And a magnetic flux distribution section that links the current flowing through the two-axis actuator.   The magnetic flux distribution section includes a first yoke having a main body portion to which one pole of a magnet is fixed and an extension portion continuous to the outside of the main body portion, and a main body portion to which the other pole is fixed and the main body A second yoke having a plurality of arm portions that are included in a plane forming the portion and projecting in two axial directions perpendicular to each other, and in the gap where the extension portion and the arm portion face each other The biaxial actuator according to claim 2, wherein a coil is provided, and the arm portion is disposed within the coil with a predetermined movable margin.   The magnetic flux distribution section includes a first yoke having a main body portion to which one pole of a magnet is fixed, a side wall portion that is continuous with the main body portion and is disposed so as to surround a side surface of the magnet, and the first yoke A second yoke having a main body portion to which the other pole of the magnet is fixed and having a plurality of arm portions extending in two axial directions orthogonal to each other and facing the side wall portion. A coil is provided in a gap provided between the side wall portion and the arm portion, and the arm portion is disposed in the coil with a predetermined movable margin. The biaxial actuator according to claim 2.   5. The device according to claim 2, wherein the first yoke and the second yoke are formed by sheet metal working by cutting and bending a plate-like soft magnetic material. 6. Shaft type actuator.   The biaxial actuator according to any one of claims 2 to 5, wherein the magnetic flux distribution section is provided on a movable shaft side, and the coil is provided on a fixed member side that supports the support mechanism.   The biaxial actuator according to any one of claims 2 to 5, wherein the coil is provided on a movable shaft side, and the magnetic flux distribution unit is provided on a fixed member. The direction of the main magnetic flux passing through the gap is set parallel to the third axis;
The one magnetic circuit forming the pair of magnetic circuits and the electromagnetic force generated in the other magnetic circuit act in opposite directions, and the support center point of the support mechanism is the rotation center of the electromagnetic force. The biaxial actuator according to any one of claims 2, 3, 5 to 7, wherein components acting in a tangential direction of the circle are in the same direction. The direction of the main magnetic flux passing through the gap is set perpendicular to the third axis;
The one magnetic circuit forming the pair of magnetic circuits and the electromagnetic force generated in the other magnetic circuit act in the same direction, and the support center point of the support mechanism is the rotation center of the electromagnetic force. The biaxial actuator according to any one of claims 2, 4, 5 to 7, wherein components acting in a tangential direction of the circle are also in the same direction.

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