JP4757573B2 - Biaxial actuator and holography device using the same - Google Patents

Description

  The present invention relates to a biaxial actuator that adjusts an incident angle of reference light to an optical recording medium by setting a reflection mirror to a desired tilt angle, and a holography device using the same.

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

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

  In the holography apparatus as described above, since the recording capacity per recording position 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, the conventional galvanometer mirror described in Patent Document 1 has a configuration in which a total of six electromagnetic coils (three on one side × 2) are provided on both side surfaces of the movable portion that holds and swings the mirror. Therefore, the weight of the movable part 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).

  The movable portion is supported by a support spring formed by deforming four wire springs. When the movable portion rotates, the support spring is elastically deformed. However, at this time, the restoring force based on the elastic deformation acts on the support spring so as to prevent the magnetic driving force (driving torque) generated by the left-hand rule. For this reason, also in this respect, there is a problem that it is difficult to increase responsiveness, and power consumption tends to increase in order to generate an appropriate driving force.

Furthermore, in what was described in patent document 1 , the said movable part is supported in the state hung with the wire spring, and it is the structure which a movable part tends to vibrate according to an external impact. For this reason, there is a problem that such a holography device is difficult to be employed as a recording device mounted on a mobile phone or the like.

  The present invention is for solving the above-described conventional problems, and provides a biaxial actuator excellent in responsiveness and a holography device using the same by efficiently using a driving force generated in a magnetic driving unit. The purpose is to do.

  Another object of the present invention is to provide a biaxial actuator excellent in shock vibration resistance and low power consumption, and a holography device using the same.

The present invention includes a movable shaft that supports a controlled object, a support mechanism that swingably supports the movable shaft around a first axis and a second axis that are orthogonal to each other, and the movable shaft that is a first axis and A biaxial actuator having a magnetic drive mechanism that tilts from a posture that coincides with a reference axis orthogonal to the second axis to a posture that tilts ;
The drive mechanism is arranged symmetrically in a second direction perpendicular to the first direction across the reference axis, and a pair of first magnetic drive units arranged symmetrically in the first direction across the reference axis A pair of second magnetic drive units,
The drive mechanism has an outer yoke provided on one of a movable side that swings together with the movable shaft and a support side that tiltably supports the movable shaft, and four coils provided on the other side,
The outer yoke is formed with four holes constituting the four magnetic drive parts of the first magnetic drive part and the second magnetic drive part, and the magnet and the inner yoke are formed in each of the hole parts. The coils are fixed, and each coil is located between the inner peripheral surface of the hole and the outer peripheral surface of the inner yoke .

In the above means, the electromagnetic force generated in each magnetic circuit can be used as a driving force for efficiently tilting the movable shaft. In addition, the magnetic circuits can be arranged in a well-balanced manner, and the magnetic circuits can be arranged together, so that downsizing can be promoted.

In the present invention, when the movable shaft coincides with the reference axis, the center axis of each hole and the center axis of each coil are arranged in a direction parallel to the reference axis. Alternatively, when the movable shaft coincides with the reference axis, the center axis of each hole and the center axis of each coil are arranged in a direction orthogonal to the reference axis.

In the present invention, the outer yoke is disposed on the movable side, the coil is disposed on the support side, a stopper pin extending from the support side along the reference axis is provided, and the stopper pin is inserted into the outer yoke. The tilt of the movable shaft can be restricted.

The stopper can restrict the inclination of the movable shaft so that the coil and the magnet do not hit each other.

The present invention provides, for example, a movable ring that supports the movable shaft so as to be swingable about the first axis, and a fixed base that supports the movable ring so as to be swingable about the second axis. And it can comprise as what has.
In the above means, the movable shaft having the control target can be reliably tilted in the biaxial direction.

  Further, the support mechanism is preferably configured to have a small ball or a pin that allows mutual rotation between the movable shaft and the movable ring and between the movable ring and the fixed base.

  In the above means, the rotation center can be fixed to the support center point of the support mechanism, and therefore, for example, even when an impact or vibration is applied, the support center point is less displaced and the actuator has excellent shock vibration resistance. can do.

A holography device according to the present invention includes at least a light source that emits a predetermined laser beam, a collimator lens that converts the laser beam into parallel light, the biaxial actuator described above, and the movable biaxial actuator. A reflection mirror provided at the other end of the shaft and reflecting toward the optical recording medium using the parallel light as reference light, and a photodetector for detecting diffracted light output from the optical recording medium are provided. It is characterized by this.

  In the holography device of the present invention, the reflecting mirror can be quickly tilted in the biaxial direction.

Oite above, the reflecting mirror, the angle theta of the reflecting mirror with respect to the reference axis is 0 degrees <theta <is preferable which is previously inclined in a range of 90 degrees.

  With the above means, the height dimension of the holographic device itself can be kept low. For this reason, it is possible to promote downsizing and thinning of a device equipped with a holography device.

  In the present invention, the electromagnetic force generated by the magnetic drive unit can be efficiently converted into a drive force for use. Therefore, it is possible to provide a biaxial actuator that has low power consumption and excellent responsiveness.

Further, the present invention can fix the rotation center to the support center point of the support mechanism, and therefore, it is possible to provide a biaxial actuator in which the shift of the support center point is small even when, for example, impact or vibration is applied. it can.

  1 is a perspective view showing a biaxial actuator provided with a reflecting mirror as an embodiment of the present invention, FIG. 2 is an exploded perspective view of FIG. 1, FIG. 3 is an exploded perspective view showing the structure of a support mechanism, and FIG. FIG. 5 is an exploded perspective view showing an example of a fixing member side constituting the magnetic drive unit, and FIG. 5 is an exploded perspective view showing an outer yoke constituting the magnetic drive unit.

  As shown in FIGS. 1 and 2, the actuator 10 </ b> A of the present invention is roughly composed of three members: a controlled object (controlled mechanism) 20, a support mechanism 30, and a magnetic drive mechanism 40. Hereinafter, each mechanism will be described in detail.

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

  The mirror support portion 22 is composed of a support plate 22a having an L-shaped cross section, and a movable shaft 22b protruding in the Z2 direction is fixed on the back surface (surface on the Z2 side in the drawing). The reflection mirror 21 is fixed via an adhesive or the like with its 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 balls 33 and 34. The fixed base 31 is a plate-like member in which a circular opening 31a that penetrates largely in the center is formed, and convex fixed portions 31b and 31b 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. On the inner peripheral surface of the movable ring 32, second recesses 32a and 32a facing the first recesses 22c and 22c are formed. In addition, third recesses 32b and 32b are formed on the outer peripheral surface of the movable ring 32 and at positions different from the second recesses 32a and 32a by 90 degrees along the circumferential direction. Further, on the inner peripheral surface of the opening 31 a of the fixed base 31, fourth recesses 31 c and 31 c facing the third recesses 32 b and 32 b are formed.

  The movable shaft 22b is inserted into the movable ring 32. At this time, small balls 33, 33 that freely rotate between the first concave portions 22c, 22c and the second concave portions 32a, 32a facing each other. Is provided. 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.

  The movable ring 32 is provided inside the opening 31a of the fixed base 31, and freely rotates between the third recesses 32b and 32b and the fourth recesses 31c and 31c facing each other. Small spheres 34, 34 are provided. For this reason, the movable ring 32 and the fixed base 31 are swung in the β1 and β2 directions relative to each other around the virtual axis QQ (second axis) connecting the small sphere 34 and the small sphere 34. It is held in a movable relationship. 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 Q-Q (second axis)) is the center of rotation (support). The support center point O) of the mechanism.

  That is, the first concave portions 22c and 22c and the second concave portions 32a and 32a form a first bearing portion (inner bearing portion), and the third concave portions 32b and 32b and the fourth concave portions 31c and 31c. And form a second bearing portion (outer bearing portion). Therefore, the movable shaft 22b is orthogonal to the virtual axis P1-P2 (first axis) and the first bearing part (inner bearing part) and the second bearing part (outer bearing part). The two virtual axes QQ (second axis) are held so as to be swingable. 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 40 mainly includes a fixing member 41 and an outer yoke 46.
As shown in FIG. 4, the fixing member 41 is formed of a metal plate or the like having a substantially U-shape. Circular bottom portions 41a, 41a, 41a, 41a are formed on the bottom surface 41A in the Z2 direction of the fixing member 41. A through hole 41b penetrating in the Z direction is formed at the center of the arrangement of the four thin portions 41a. It has been drilled. A rod-like stopper pin 43 extending in the Z1 direction from the Z2 side in the figure is inserted through the through hole 41b.

  Further, side wall portions 41B and 41B extending continuously in the Z1 direction shown in the drawing are provided at both ends of the bottom surface 41A. In addition, elongated holes 41c and 41c that extend in the X direction and extend in the Y direction are formed at the ends of the side wall portions 41B and 41B. Fixing portions 31b and 31b formed in the fixing base 31 can be fitted into the long holes 41c and 41c. That is, the fixed base 31 is supported by the fixed member 41.

  Coils 42 (indicated by 42A, 42B, 42C, and 42D, respectively) are attached to the four thin portions 41a. Each coil 42 is formed into a coil shape by, for example, winding a covered wire covered with a heat-sealable resin around a bobbin (core material) having a predetermined outer dimension a predetermined number of times. Is an air-core coil formed by melting the resin by placing it in a high temperature environment, fixing each wire, returning to room temperature, and pulling out the bobbin.

  The two coils 42 provided at symmetrical positions with the stopper pin 43 in between are formed of a single wire. That is, the coil 42A and the coil 42C arranged in the direction along the virtual axis P1-P2 (first axis) are connected in series by being formed of a single wire, and the virtual axis Q-Q ( A coil 42B and a coil 42D arranged in a direction along the second axis) are connected in series.

  As shown in FIG. 5, the outer yoke 46 is made of an Fe-based metallic magnetic material such as ferrite, and has a hole 47 (individually recessed) that opens in the Z1 direction shown in the figure. 47A, 47B, 47C, and 47D). The substantially cylindrical magnet M and the end surfaces of the inner yoke 48 are fixed to the center of the bottom surface of each hole 47 in a state where they are connected in the Z direction (see FIG. 6).

  The inner diameter of the four holes 47 is formed larger than the outer dimensions of the four coils 42, and the outer dimensions of the magnets M and the inner yoke 48 are formed smaller than the inner dimensions of the four coils 42. Has been. A gap G having a predetermined clearance is formed between the magnet M and the side surface (outer peripheral surface) of the inner yoke 48 and the inner peripheral surface of the hole 47, and four coils 42A, 42B, 42C and 42D are inserted in each gap G (see FIG. 6). Clearance margins are also formed between the inner circumferential surface of each coil 42 and each magnet M and the outer circumferential surface of the inner yoke 48 and between the outer circumferential surface of each coil 42 and the inner circumferential wall surface of each hole 47. Yes. Therefore, as will be described later, when the outer yoke 46 is inclined with respect to the Z direction, each coil 42 can move relatively in the gap G in the axial direction (Z direction) and the plane (XY direction). It has become.

  As shown in FIGS. 2 and 4, a through hole 46 a into which the stopper pin 43 is inserted is formed at the center of the four holes 47 </ b> A, 47 </ b> B, 47 </ b> C, 47 </ b> D of the outer yoke 46.

  As shown in FIG. 6, a fitting convex portion 46b is integrally formed on the bottom surface (Z1 side surface) of the outer yoke 46 and around the through hole 46a. And this fitting convex part 46b and the movable shaft 22b formed in the said mirror support part 22 are fitted by interposing the support mechanism 30 between these.

  As shown in FIG. 2, fixing portions 31 b and 31 b which are both sides of the fixing base 31 are fitted and fixed in the long holes 41 c and 41 c formed in the fixing member 41. The mirror support portion 22 and the outer yoke 46 are connected via the movable shaft 22b and the fitting convex portion 46b, and the periphery of the movable shaft 22b is swingably provided in the fixed base 31. The movable ring 32 is held swingably.

  Therefore, when a driving force as will be described later is applied, the mirror support portion 22 and the outer yoke 46 are XY with respect to the Z axis (third axis) passing through the rotation center (support center point) O. It can be tilted integrally in the plane direction.

  When the inclination angle of the outer yoke 46 with respect to the Z-axis (third axis) is increased, the outer peripheral surface of the coil 42 abuts on the inner peripheral wall surface of the hole 47 or each magnet is placed on the inner peripheral surface of the coil 42. It is assumed that M and the outer peripheral surface of the inner yoke 48 may come into contact with each other and be damaged. For this reason, the stopper pin 43 is set to contact the through hole 46a before such contact occurs, and the inclination angle of the outer yoke 46 is limited to be within a predetermined range. Has been. Therefore, the damage between the outer peripheral surface of each coil 42 and the inner peripheral wall surface of each hole 47 and the damage between the inner peripheral surface of each coil 42, each magnet M, and the outer peripheral surface of the inner yoke 48 will be described. It is possible to prevent.

Next, the operation of the biaxial actuator will be described.
FIG. 6 is a cross-sectional view of the magnetic drive unit for explaining the operation of the biaxial actuator according to the first embodiment of the present invention, for example, showing a cross section along a virtual axis P1-P2 (first axis). Is. In FIG. 6, the support mechanism 30 is omitted.

  As shown in FIG. 6, for example, the magnet M1 in the hole 47A is fixed to the bottom surface of the hole 47A (the bottom of the outer yoke member) with the end face on the S pole side facing the Z1 direction. The end face of the inner yoke 48 is fixed to the other end face on the N pole side. For this reason, the magnetic flux B is a magnetic circuit (magnetic path) consisting of a path of N pole of the magnet M → inner yoke → gap G (coil 42A) → outer side wall of the outer yoke → bottom of the outer yoke → S pole of the magnet M. Form.

  The magnet M2 in the hole 47C is fixed to the bottom surface of the hole 47C (the bottom of the outer yoke member) with the end face on the N pole side facing the Z1 direction. The end face of the inner yoke 48 is fixed to the other end face on the S pole side. For this reason, the magnetic flux B is a magnetic circuit (magnetic path) consisting of a path of the N pole of the magnet M2 → the bottom of the outer yoke → the outer side wall of the outer yoke → the gap G (coil 42C) → the inner yoke → the S pole of the magnet M2. Form.

  In the gap G, the direction of the magnetic flux B and the winding direction of the coil are orthogonal. Therefore, when a predetermined current I is passed through the coils 42A and 42C connected in series with each other, an electromagnetic force due to the action of the magnetic flux B and the current I can be generated in accordance with the direction of the current I. .

  That is, when viewed in the direction of arrow A1 in FIG. 6, if a clockwise current I is passed through the coil 42A and a clockwise current I is passed through the coil 42C, the coil 42A The electromagnetic force F1 ′ acting on the coil is in the Z2 direction shown in the figure, and the electromagnetic force F2 ′ acting on the coil 42C is in the Z1 direction shown in the figure.

  Since the coils 42A and 42C are fixed in the thin portions 41a and 41a of the bottom surface 41A of the fixing member 41, the coils 42A and 42C themselves cannot move. For this reason, as shown in FIG. 6, a force F1 as a reaction of the electromagnetic force F1 ′ acts on the coil 42A in the Z1 direction via the inner yoke 48 and the magnet M1, and the coil 42C receives the electromagnetic force F2 ′. As a reaction, the force F2 acts in the Z1 direction via the inner yoke 48 and the magnet M2.

  That is, opposite forces F1 and F2 can be applied to the coil 42A and the coil 42C. 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 around the support center point O. 46 can be tilted clockwise in FIG. 6 (in the direction β1 around the virtual axis QQ (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).

  As described above, the coil 42A, the hole 47A, the magnet M1 and the inner yoke 48 form one magnetic circuit, and the coil 42C, the hole 47C, the magnet M2 and the inner yoke 48 form another magnetic circuit. Forming. Such a pair of magnetic circuits forms a first magnetic drive unit that rotates the outer yoke 46 in the β1 and β2 directions.

  Further, when the direction of the current I is opposite to the above example (counterclockwise direction when viewed from the direction of the arrow A1), the outer yoke 46 is rotated counterclockwise (virtual axis QQ (second axis) in FIG. Can be tilted in the direction of β2).

  In this way, by changing the direction of the current I, the movable shaft 22b is swung in the clockwise direction (β1 direction) and the counterclockwise direction (β2 direction) with the rotation center (support center point) O as the center. Is possible.

  The above relationship is the same in the magnetic circuit including the coil 42B provided in the hole 47B and the coil 42D provided in the hole 47D. That is, by changing the direction of the current I flowing through the coil 42B and the coil 42D, the virtual axis QQ (second axis) having the movable shaft 22b as the rotation center (support center point) O, that is, 2 can be swung in the α1 direction and the α2 direction, respectively.

  In this case, the coil 42B, hole 47B, magnet M1 and inner yoke 48 form one magnetic circuit, and the coil 42D, hole 47D, magnet M2 and inner yoke 48 form another magnetic circuit. Forming. The pair of magnetic circuits form a second magnetic drive unit that rotates the outer yoke 46 in the α1 and α2 directions.

  For this reason, the movable shaft connected via the fitting convex part 46b of the said outer yoke 46 by using the said 1st magnetic drive part and the 2nd magnetic drive part arrange | positioned in the direction orthogonal to this. 22b can be tilted from a posture that coincides with the Z-axis (third axis; reference axis) to a posture that tilts. Therefore, it is possible to tilt the control object 20 provided with the movable shaft 22b, that is, the reflection mirror 21 freely in the biaxial direction.

  In the present embodiment, a reflection mirror 21 as the control target is provided at one end on the Z1 side of the movable shaft 22b, and a magnetic drive mechanism including the first and second magnetic drive units at the other end on the Z2 side. The support center point O of the support mechanism is set to be near the center of gravity on the movable shaft 22b connecting the control target and the magnetic drive mechanism. Therefore, the biaxial actuator 10 is excellent in balance as an actuator and can be driven without difficulty.

Next, a second embodiment of the present invention will be described.
FIG. 7 is a cross-sectional view similar to FIG. 6 for explaining the operation of the biaxial actuator according to the second embodiment .

The magnetic drive mechanism 40 is mainly different between the second embodiment and the first embodiment. That is, the first embodiment is a MM type (Moving Magnet type), whereas the biaxial actuator of the second embodiment is a so-called MC type (Moving Coil type). Yes. However, the configurations of the control target 20 and the support mechanism 30 are common to both the first and second embodiments. In FIG. 7, the support mechanism 30 is omitted as in FIG.

As shown in FIG. 7, in the biaxial actuator 10B of the second embodiment , a flat movable base 51 is connected to the tip of the movable shaft 22b. Four air-core coils 42A, 42B, 42C, and 42D having the same configuration as that of the first embodiment are fixed to the surface of the movable base 51 on the Z2 side with their open ends directed in the Z direction. Has been. In FIG. 7, only the coils 42A and 42C are shown, and the coils 42B and 42D are omitted.

  An outer yoke 46 having the same configuration as described above is fixed to the fixing member 41. That is, the outer yoke 46 has four hole portions 47 (indicated by 47A, 47B, 47C, and 47D, respectively), and a substantially cylindrical magnet M and an inner yoke 48 are provided at the center of the bottom surface of each hole portion 47. The end faces are fixed in a state where they are connected in the Z direction. A gap G is formed between the side surface (outer peripheral surface) of the magnet M and the inner yoke 48 and the inner peripheral surface of the hole 47, and the four coils 42A, 42B, 42C, 42D are connected to the gap G. It is arranged with a predetermined movable margin inside.

  In this case as well, one magnetic circuit composed of the coil 42A, the hole 47A, the magnet M1 and the inner yoke 48 and the other magnetic circuit composed of the coil 42C, the hole 47C, the magnet M2 and the inner yoke 48 are the first. One magnetic circuit comprising a coil 42B, a hole 47B, a magnet M1 and an inner yoke 48 and another magnetic circuit comprising a coil 42D, a hole 47D, a magnet M2 and an inner yoke 48 are formed. A second magnetic drive unit can be formed.

  When a current I in a predetermined direction is applied to the coils 42A and 42C constituting the first magnetic drive unit, electromagnetic forces F1 (Z1 direction) and F2 (Z2 direction) in opposite directions are applied to the coils 42A and 42C, respectively. The electromagnetic force acting in the opposite direction can be generated by changing the direction of the current I. Therefore, the movable shaft 22b fixed to the movable base 51 can be swung clockwise (β1 direction) or counterclockwise (β2 direction) with respect to the rotation center (support center point) O as described above. .

  Similarly, when a current I in a predetermined direction is applied to the coils 42B and 42D constituting the second magnetic drive unit, electromagnetic forces F1 (Z1 direction) and F2 (Z2 direction) in opposite directions are applied to the coils 42B and 42D, respectively. Further, when the direction of the current I is changed, an electromagnetic force acting in the opposite direction can be generated. For this reason, the movable shaft 22b fixed to the movable base 51 can be swung clockwise (α1 direction) or counterclockwise (α2 direction) with respect to the rotation center (support center point) O.

For this reason, also in the biaxial actuator 10B of the second embodiment , the controlled object 20 can be freely tilted in the biaxial direction.

FIG. 8 is a cross-sectional view similar to FIG. 6 for explaining the operation of the biaxial actuator of the third embodiment .

The biaxial actuator 10C of the third embodiment is an MM type (Moving Magnet type) actuator similar to that of the first embodiment. However, in the third embodiment, the arrangement relationship of the outer yoke 56 and the four coils 52A, 52B, 52C, and 52D is mainly different from that of the first embodiment. The configurations of the control target 20 and the support mechanism 30 are the same as those in the first and second embodiments.

  The outer yoke 56 of the biaxial actuator 10C also has four holes 57A, 57B, 57C, and 7D. However, the opening directions are directions different from each other by 90 degrees with respect to the Z axis (third axis) passing through the support center point O. For example, the hole portion 57A and the hole portion 57C are provided at positions different by 180 degrees with respect to the Z axis passing through the support center point O, and both are formed to open in a direction along the virtual axis P1-P2 (first axis). Further, the hole portion 57B and the hole portion 57D are provided at positions different from each other by 180 degrees with respect to the Z axis passing through the support center point O, and both are formed to open in a direction along the virtual axis QQ (second axis). As shown in FIG. 2, the relationship between the virtual axis P1-P2 (first axis) and the virtual axis Q-Q (second axis) is orthogonal to the Z axis (third axis). is doing.

  A fitting convex portion 56b is formed to protrude from the surface of the outer yoke 56 on the Z1 side, and the end portion of the movable shaft 22b is connected and fitted to the outer periphery of the fitting convex portion 56b. The movable shaft 22b is swingably supported by a support mechanism 30 fixed to the same fixed member 41 as described above.

  In each of the holes 57A to 57D, a substantially cylindrical magnet M and an inner yoke 48 connect the end faces of each other, and the end face of the magnet M is fixed to the center of the bottom surface of each hole 57. . A gap G is formed between the side surface (outer peripheral surface) of the magnet M and the inner yoke 48 and the inner peripheral surface of the hole 57.

  On the other hand, the fixing member 41 has four side wall portions 41B facing each other with a Z axis (third axis) passing through the support center point O as a center. In the four side walls 41B, four coils 52A, 52B, 52C and 52D are provided so that the opening directions thereof are orthogonal to the Z axis (third axis) passing through the support center point O. Respectively. The four coils 52A, 52B, 52C, 52D are arranged with a predetermined allowance in the gap G provided in each of the holes 57A, 57B, 57C, 7D.

  As the magnetization state of the magnet M, for example, when the Z-axis (third axis) side passing through the support center point O is the S pole and the side wall 41B side is the N pole, each magnetic flux B is in the magnetic drive mechanism 40. Each of the coils 52A, 52B, 52C, 52D can be formed with a magnetic circuit (magnetic path) as shown in FIG.

  For this reason, when a current I in a predetermined direction is applied to the coils 52A, 52B, 52C and 52D, electromagnetic forces F1 and F2 in the same direction (P1 direction in FIG. 8) are generated in the coils 52A and 52C, respectively. Can do. When the direction of the current I applied to the coils 52A, 52B, 52C and 52D is reversed, the directions of the electromagnetic forces F1 and F2 can be reversed (P2 direction).

  Here, the coil 52A, the hole 57A, the magnet M1 and the inner yoke 58 form one magnetic circuit, and the coil 52C, the hole 57C, the magnet M2 and the inner yoke 58 form another one magnetic circuit. Yes. The one magnetic circuit and the other magnetic circuit form a first magnetic drive unit that rotates the outer yoke 56 in the β1 and β2 directions.

  Similarly, the coil 52B, the hole 57B, the magnet M1 and the inner yoke 58 form one magnetic circuit, and the coil 52D, the hole 57D, the magnet M2 and the inner yoke 58 form another one magnetic circuit. . The one magnetic circuit and the other magnetic circuit form a second magnetic drive unit that rotates the outer yoke 56 in the α1 and α2 directions.

  As shown in FIG. 8, the electromagnetic forces F1 and F2 generated in the first magnetic drive unit and the second magnetic drive unit are components tangential to a circle F1a and F2a centered on the support center point O, as shown in FIG. Each can be decomposed into radial components F1b and F2b. Among these, the components that contribute to the driving force for tilting the movable shaft 22b are the tangential components F1a and F1b. The magnitudes of the tangential components F1a and F2a are larger than the magnitudes of the radial components F1b and F2b (| F1a |> | F1b |, | F2a |> | F2b |).

On the other hand, in the first and second embodiments , conversely, the magnitudes of the tangential components F1a and F2a are smaller than the magnitudes of the radial components F1b and F2b (| F1a | <| F1b |, | F2a | <| F2b |).

Therefore, in the third embodiment, the electromagnetic forces F1 and F2 generated in the first and second magnetic drive units are driven to swing the movable shaft 22b as compared with the above embodiment and the reference example. The forces F1a and F2a can be efficiently used.

  That is, similar driving forces F1a and F2a can be obtained with low power consumption. Alternatively, since the larger driving forces F1a and F2a can be generated with the same power consumption, the response as an actuator can be improved.

Since in the above-described biaxial actuator of the first embodiment to the third embodiment, having a first magnetic drive portion and the second magnetic drive which is arranged so as to be perpendicular to each other, The drive shaft 22b can be freely tilted in two axial directions.

  That is, by controlling the direction and magnitude of each of the currents I flowing through the coils 42A and 42C constituting the first magnetic drive unit and the coils 42B and 42D constituting the second magnetic drive unit, The control object 20 can be set to a desired angle. For this reason, it is possible to freely adjust the tilt angle of the reflection mirror 21 fixed to the mirror support portion 22 constituting the control object 20.

Next, a holography device using the biaxial actuator will be described.
FIG. 9 is a perspective view showing an outline of the arrangement relation of each member constituting the holography device, and FIG.

  The holographic device shown in FIG. 9 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 shown in FIG. 9 is mainly composed of an optical system composed of 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 L2 reflected by the reflection mirror 21 can illuminate a predetermined position on the optical recording medium 70. The angle adjustment of the reflection mirror 21 is performed by applying the current I having a predetermined direction and magnitude to the four coils forming the first magnetic drive unit and the second magnetic drive unit as described above. be able to.

  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.

FIG. 11 is a side view showing another shaft type actuator.
In the holography apparatus shown in FIGS. 9 and 10, the reference light L <b> 2 emitted from the collimator lens 62 is horizontal with respect to the optical recording medium 70. In the reflection mirror 21, it is necessary to make the inclination angle of the reflection mirror 21 downward so that the horizontal reference light L <b> 2 becomes a predetermined incident angle θ when entering the optical recording medium 70. In some cases, the tilt angle exceeds the adjustment range of the actuator 10. In this case, as shown in FIGS. 9 and 10, the actuator 10 itself is attached in advance to the inside of the optical recording medium reproducing apparatus with a predetermined tilt posture. It will be necessary.

  However, if the actuator 10 itself is attached to the inside of the optical recording medium reproducing device in a predetermined tilted posture in advance, the bottom surface 41A side of the fixing member 41 constituting the actuator 10 is lifted, and the overall height dimension of the holographic device is high. Therefore, there arises a problem that it is difficult to reduce the thickness.

  In such a case, for example, a configuration in which a reflection mirror (control target) 21 is previously attached to the tip of the movable shaft 22b in an inclined posture like a biaxial actuator 10D shown in FIG. In this case, the tilting posture of the reflection mirror (control target) 21 is determined between the Z axis (third axis; reference axis) passing through the support center point O of the movable shaft 22b and the surface 21a of the reflection mirror 21. The angle θ formed is set to be in the range of 0 degree <θ <90 degrees.

  In this way, since the actuator 10D can be mounted in a horizontal posture in the optical recording medium reproducing apparatus, there is no need to fix the fixed member 41 constituting the actuator 10D in a state where the bottom surface 41A is lifted, and the holography apparatus As a result, the overall height dimension of the optical recording medium can be kept low, and it is possible to promote the miniaturization and thinning of the optical recording medium reproducing apparatus equipped with the same.

  In the support mechanism 30 of each of the embodiments described above, first spheres 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, the rotating pin and a bearing member that supports the rotating pin are used. There may be. 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.

Perspective view of a two-axis actuator having a reflection mirror embodiment of the present invention, 1 is an exploded perspective view of FIG. An exploded perspective view showing the structure of the support mechanism; An exploded perspective view showing an example of the fixing member side constituting the magnetic drive unit; An exploded perspective view showing an outer yoke constituting the magnetic drive unit; Sectional drawing of the magnetic drive part for demonstrating operation | movement of the biaxial actuator of the 1st Embodiment of this invention, Sectional drawing similar to FIG. 6 for demonstrating operation | movement of the biaxial actuator of the 2nd Embodiment of this invention, Sectional drawing similar to FIG. 6 for demonstrating operation | movement of the biaxial actuator of the 3rd Embodiment of this invention, The perspective view which shows the outline of the arrangement | positioning relationship of each member which comprises a holography apparatus, FIG. 9 is a front view corresponding to the direction of the arrow in FIG. A side view showing another biaxial actuator of the present invention,

10, 10A, 10B, 10C, 10D 2-axis actuator 20 Control target (controlled mechanism)
21 Reflection mirror (control target)
22 mirror support portion 22b movable shaft 30 support mechanism 31 fixed base 32 movable rings 33 and 34 small sphere 40 magnetic drive mechanism 41 fixed member 41b through hole 42, 42A, 42B, 42C, 42D coil 43 stopper pin 46 outer yoke 46a through hole 47, 47A, 47B, 47C, 47D Hole 48 Inner yoke 51 Movable base 52A, 52B, 52C, 52D Coil M Magnet O Rotation center (support center point of support mechanism)
P1-P2 virtual axis (first axis)
QQ virtual axis (second axis)

Claims (9)

A movable shaft that supports the object to be controlled, a support mechanism that swingably supports the movable shaft around the orthogonal first and second axes, and the movable shaft as the first and second axes. A biaxial actuator having a magnetic drive mechanism that tilts from a posture that matches a reference axis orthogonal to
The drive mechanism is arranged symmetrically in a second direction perpendicular to the first direction across the reference axis, and a pair of first magnetic drive units arranged symmetrically in the first direction across the reference axis A pair of second magnetic drive units,
The drive mechanism has an outer yoke provided on one of a movable side that swings together with the movable shaft and a support side that tiltably supports the movable shaft, and four coils provided on the other side,
The outer yoke is formed with four holes constituting the four magnetic drive parts of the first magnetic drive part and the second magnetic drive part, and the magnet and the inner yoke are formed in each of the hole parts. A biaxial actuator characterized in that each coil is fixed and located between the inner peripheral surface of the hole and the outer peripheral surface of the inner yoke . 2. The biaxial type according to claim 1, wherein when the movable shaft coincides with the reference axis, the center axis of each hole and the center axis of each coil are arranged in a direction parallel to the reference axis. Actuator. 2. The biaxial type according to claim 1, wherein when the movable shaft coincides with a reference axis, the center axis of each hole and the center axis of each coil are arranged in a direction orthogonal to the reference axis. Actuator. The outer yoke is disposed on the movable side, and the coil is disposed on the support side;
3. The biaxial actuator according to claim 2, wherein a stopper pin extending along the reference axis from the support side is provided, and the stopper pin is inserted into the outer yoke to restrict the inclination of the movable shaft . The biaxial actuator according to claim 4, wherein an inclination of the movable shaft is restricted by the stopper so that the coil and the magnet do not hit each other . The support mechanism includes a movable ring that supports the movable shaft to be swingable about the first axis, and a fixed base that supports the movable ring to be swingable about the second axis. The biaxial actuator according to any one of 1 to 5 . The biaxial actuator according to claim 6 , wherein the support mechanism includes small spheres that allow rotation between the movable shaft and the movable ring and between the movable ring and the fixed base. A light source that emits at least a predetermined laser beam, a collimator lens that converts the laser beam into parallel light, the biaxial actuator according to any one of claims 1 to 7 , and a movable axis of the biaxial actuator And a reflection mirror that reflects the parallel light as reference light toward the optical recording medium, and a photodetector that detects diffracted light output from the optical recording medium. Holographic device to do. 9. The holography device according to claim 8 , wherein the reflection mirror is tilted in advance within an angle θ of a mirror surface with respect to the reference axis in a range of 0 degree <θ <90 degrees.

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