JPH0612686A - Biaxial actuator - Google Patents

Abstract

PURPOSE:To improve driving control by arranging the intersected point and working point of leaf springs within the plane passing the centroid of moving parts. CONSTITUTION:A holder 9, leaf spring 11 and coil 13 constitute a moving body 19. A holder 17, leaf spring 23 and coil 25 constitute a moving body 29. The integrated holders 9 and 17 are placed on the base part 31a of a base 31. The moving plane in the direction of a projecting part 10 passing the fulcrum 15 and working point 12 of the leaf spring 11 and the centroid of the moving body 19 and the moving plane in the direction of a projecting part 22 passing the intersected point 27 and working point 24 of the leaf spring 23 and the centroid of the moving body 29 are made flush with each other. Consequently, the respective independent driving control of a corner cube 8 in the X-axis direction and Y-axis direction is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxial actuator for biaxially driving a mirror or a corner cube used for controlling an optical axis in a precision XY stage, an optical head or the like.

[0002]

2. Description of the Related Art Conventionally, an actuator in an optical axis control device is different depending on its control mechanism, and an optical axis control is performed by using a mirror or a corner cube. As an example using a mirror, for example, a so-called gimbal mechanism that rotates about two axes orthogonal to each other as disclosed in JP-A-2-120816 is used. An example of using a corner cube is, for example, Japanese Patent Laid-Open No. 2-28.
As disclosed in Japanese Patent No. 9927, a corner cube or the like is supported by a plurality of wires or leaf springs so as to be biaxially movable.

FIG. 5 shows a mechanism for controlling an optical axis using a corner cube. The laser emission light passes through the relay lens 1 and the collimator lens 2, is reflected by the mirror 3, is reflected by the corner cube 4, is transmitted through the λ / 4 plate 5, and is transmitted or reflected by the polarization beam splitter 6. The transmitted light is detected by the four-division light receiving element 7 and used as a beam for controlling the optical axis, and the reflected light is used as a beam for emission after controlling the optical axis.

In this case, when the laser emission light shown by the solid line is displaced along the optical axis as shown by the alternate long and short dash line, the optical axis shift is detected by the four-division light receiving element 7, and the optical axis shift is matched accordingly. The corner cube 4 is moved by the amount in the direction indicated by the arrow (here, the position indicated by the dotted line in the left direction). Accordingly, the light reflected by the polarization beam splitter 6 can be used as laser light whose optical axis is controlled.

[0005]

In the gimbal mechanism and the optical pickup mechanism described above, when one axis is driven, a so-called crosstalk phenomenon occurs in which the other axis is also displaced. Particularly, in the latter optical pickup mechanism, the crosstalk at the time of primary resonance in both driving directions becomes very large and it may be impossible to control.

Further, in the case of the optical pickup mechanism, since the reaction force applied to the action point of the leaf spring, the wire, etc. does not pass through the center of gravity of the movable body, a plurality of them are combined and the reaction force is always unbalanced. The movable body may roll and become out of control.

Further, in the case of the optical pickup mechanism, since the coil for biaxial driving is arranged in the gap of one magnetic circuit, the driving sensitivity varies depending on the displacement position of the movable body, which lowers the control capability. I will end up. Moreover, since the magnetic gap cannot be reduced, the magnetic circuit cannot be downsized.

[0008]

According to a first aspect of the present invention, a first holder that holds a corner cube and has a first protrusion that is formed so as to project in a uniaxial direction and the first protrusion have a first action. A first leaf spring supported at a point and a first leaf spring connected to the first holder via the first leaf spring.
A first movable part including a coil, a first magnetic circuit arranged in the same direction as the axis of the first movable part, the first holder inside, and the first leaf spring as a first fulcrum. And a second holder having a second protrusion formed to protrude from a second side face orthogonal to the first side face at the same time as being fixed to the first side face, and a second holder for supporting the second protrusion part at a second action point. A second movable part composed of a leaf spring and a second coil connected to the second holder via the second leaf spring, and a second magnet arranged in the same direction as the axis of the second movable part. A circuit, a third side surface to which the second leaf spring is fixed at a second fulcrum, and the second side surface.
A biaxial actuator consisting of a base having a bottom portion on which the holder is installed was provided.

According to a second aspect of the invention, in the first aspect of the invention, the centers of gravity of the first movable portion and the second movable portion are made to coincide with each other.

According to a third aspect of the present invention, in the first aspect of the invention, the first fulcrum and the first action point of the first leaf spring and the first protrusion in the direction of the first protrusion passing through the center of gravity of the first movable portion. The first movable plane, the second fulcrum and the second action point of the second leaf spring, and the second movable plane in the direction of the second protrusion passing through the center of gravity of the second movable section are aligned.

According to a fourth aspect of the invention, in the invention of the first aspect, the first leaf spring surface excluding the first fulcrum and the first action point of the first leaf spring and the second fulcrum of the second leaf spring and A damper member was arranged on each of the second leaf spring surfaces excluding the second action point.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the magnetic gaps of the first magnetic circuit and the second magnetic circuit for generating the driving force in each movable direction are the bottom of the base. It was arranged so as to be parallel.

[0013]

According to the first aspect of the invention, since the fulcrum of the leaf spring and the point of action are arranged in a plane passing through the center of gravity of the movable portion, the rolling of the movable portion caused by the acceleration force when the other shaft operates. The force balances with the moment force generated around the center of gravity at the fulcrum of the leaf spring, which makes it possible to prevent crosstalk.

According to the second aspect of the present invention, the centers of gravity of the movable parts of both the two axes are made coincident with each other, and the reaction force acting on the action points of all the leaf springs passes through the center of gravity, so that no moment force around the center of gravity is generated. It is possible to prevent the rolling phenomenon from occurring in both movable parts.

According to the third aspect of the present invention, by making the operating planes of the two axes coincide with each other, it is possible to eliminate the possibility of being excited by high-order resonance due to interference of the other axis.

According to the fourth aspect of the invention, the fulcrum of the leaf spring is
By providing the damper member in the portion excluding the point of action, it is possible to reduce the hysteresis when moving.

According to the fifth aspect of the invention, since the magnetic gap for generating the driving force is provided biaxially and in parallel with the base, the magnetic flux density becomes uniform and the driving sensitivity can be stabilized. Become.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. Here, 2 when using a corner cube
The configuration of the shaft actuator will be described. First, the corner cube 8 is fixed to a cube holder 9 as a first holder, and the cube holder 9 has a first protrusion 10 formed in the X-axis direction. This protrusion 1
0 is the first portion of the central portion of the first leaf spring 11 having two free ends.
It is fixed by a fixing screw 14 at the point of action 12 via the first coil 13. The first coil 13 includes a drive coil 13a and a bobbin 13b around which the coil is wound. Further, fixing screws 16 are fitted to the first fulcrums 15 provided at two positions on the right and left sides of the first plate spring 11, whereby the first plate spring 11 is fixed to the first side surface 18. As described above, the first holder 9, the first leaf spring 11, and the first coil 13 form the first movable body 19 as the first movable portion.
Are configured. The same X as the axis of the first movable body 19
A first magnetic circuit 20 is arranged in the axial direction. The first magnetic circuit 20 includes a yoke 20a and a permanent magnet 20b.
And a pole piece 20c.

A second side surface 21 is formed at a position orthogonal to the first side surface 18 of the second holder 17. In the Y-axis direction in which the second side surface 21 is formed, the second protrusion 2
2 is formed. The protrusion 22 is fixed by a fixing screw 26 via a second coil 25 at a second action point 24 in the center of a second leaf spring 23 having two free ends. The second coil 25 includes a drive coil 25a and a bobbin 25b around which the coil is wound. In addition, the second leaf springs 23 are provided with second
A fixing screw 28 is fitted to the fulcrum 27, so that the second
The leaf spring 23 is fixed to the second side surface 21. As described above, the second holder 17, the second leaf spring 23, and the second coil 25 form the second movable body 29 as the second movable portion. In the same Y-axis direction as the axis of the second movable body 29,
The second magnetic circuit 30 is provided. The first magnetic circuit 30 includes a yoke 30a, a permanent magnet 30b, and a pole piece 30c.

The first holder 9 and the second holder 17 integrated in this way are combined with each other by the bottom surface 31a of the base 31.
Placed on top. Third side surfaces 31b are formed on both sides of the bottom surface portion 31a (the configuration up to this point corresponds to claim 1).

Further, in this embodiment, the following various conditions are set. First, the center of gravity G of the first movable body 19 and the center of gravity G ′ of the second movable body 29 are arranged so as to coincide with each other (corresponding to claim 2).

The first fulcrum 15 and the first action point 12 of the first leaf spring 11, the first movable plane (not shown) in the direction of the first protrusion 10 passing through the center of gravity G of the first movable body 19, and the second plate. Spring 2
Second fulcrum 27, second action point 24, and second movable body 2
The second movable plane (not shown) in the direction of the second protrusion 22 passing through the center of gravity G ′ of 9 is made to coincide (corresponding to claim 3). That is, in other words, the first fulcrum 15 and the first point of action 12 of the first leaf spring 11 pass through the center of gravity G of the first movable body 19 and are provided in a movable plane parallel to the bottom surface portion 31a of the base 31. Has been. In addition, the second of the second plate spring 23
The fulcrum 27 and the first action point 24 are provided in a movable plane that passes through the center of gravity of the second movable body 29 and is parallel to the bottom surface portion 31 a of the base 31.

The first leaf spring surface of the first leaf spring 11 excluding the first fulcrum 15 and the first action point 12 and the second leaf spring 23 of the second leaf spring 23 excluding the second fulcrum 27 and the second action point 24. The damper members 32 and 33 are respectively arranged on the leaf spring surface (corresponding to claim 4). As the damper members 32 and 33, for example, butyl rubber or the like can be used.

A magnetic gap (not shown) of each of the first magnetic circuit 20 and the second magnetic circuit 30 for generating a driving force in each movable direction is arranged so as to be parallel to the bottom surface portion 31a of the base 31 (Claims). 5).

A mechanism capable of independently driving and controlling the corner cube 8 in the X-axis and Y-axis directions in such a configuration will be described. Now, by energizing from the coil end of the drive coil 13a, the corner cube 8 becomes X.
The corner cube 8 can be moved in the axial direction, and the corner cube 8 can be moved in the Y-axis direction by energizing the coil end of the drive coil 25a. As a result, the corner cube 8 becomes movable in the XX 'and YY' directions.

FIG. 2 shows the first movable body 19 and the second movable body 2.
9 shows the force relationship acting on 9, that is, the acceleration force generated by the interference of the other axes. First, in the X-axis direction, from the balance of acceleration forces,

[0027]

[Equation 1]

[0028] Also, from the balance relation around the center of gravity of the moment due to acceleration forces, the _{2RyxLy 1 -2RyxLy 2 = 0 Ly 1} = Ly 2.

On the other hand, in the Y-axis direction, from the balance of acceleration forces,

[0030]

[Equation 2]

It becomes Further, from the balance relation of the moment around the center of gravity due to the acceleration force, 2RxyLx ₁ -2RxyLx ₂ = 0 Lx ₁ = Lx ₂ .

However,

[0033]

[Equation 3]

Since the above-described equations are established based on the dynamical relationship of FIG. 2, crosstalk as indicated by the dotted line of f _{1 in} FIG. 3 does not occur.

[0035]

[Outer 1]

Even if the movable body weight centers G and G'do not match, the above relational expression holds.

As described above, in this configuration, the first
Since the center of gravity G of the movable body 19 and the center of gravity G ′ of the second movable body 29 are the same, the moment forces around the center of gravity are balanced, and the forces acting on the first action point 12 and the second action point 24 are respectively Since the center of gravity G, G'is passed, the rolling of the movable body itself does not occur, and thereby the drive control of the movable body can be improved. Further, since the operation planes of both X and Y axes are coincident with each other, even if the secondary resonance that occurs in the other axis, that is, f ₃ of the dotted line portion in FIG. Never.

Further, since the damper members 32 and 33 made of butyl rubber or the like are not provided in the fixing portions of the leaf springs 11 and 23, there is no structural hysteresis as shown in FIG. Since the hysteresis when moving is small as described above, the accuracy of drive control of the movable body can be improved.

Further, since the magnetic gaps for generating the driving force are provided independently of the two axes in parallel with the base 31, the magnetic flux density can be made uniform, and FIG.
There is no change in displacement sensitivity (inclination) as indicated by the alternate long and short dash line 34, and the linear characteristic as indicated by the solid line 35 can be obtained. By making the magnetic flux density uniform in this way, the drive sensitivity is stabilized and the drive control accuracy can be improved. Moreover, since the gap of the magnetic circuit can be narrowed, the size can be reduced.

[0040]

According to the first aspect of the present invention, the first embodiment is formed so as to hold the corner cube and project in the uniaxial direction.
A first holder having a protrusion, a first leaf spring supporting the first protrusion at a first point of action, and a first coil connected to the first holder via the first leaf spring 1 movable part, a first magnetic circuit arranged in the same direction as the axis of the first movable part, and the first holder inside, and the first leaf spring on the first side face at the first fulcrum. A second holder having a second protrusion formed at the same time as being fixed and projecting from a second side face orthogonal to the first side face, and a second leaf spring supporting the second protrusion at a second action point, and A second movable part made up of a second coil connected to the second holder via a two leaf spring; a second magnetic circuit arranged in the same direction as the axis of the second movable part; Two leaf springs have a third side surface fixed at a second fulcrum and a bottom surface portion on which the second holder is installed. Since the biaxial actuator consisting of the base is provided, by arranging the fulcrum and action point of the leaf spring in the plane passing through the center of gravity of the movable part in this manner, the movable force generated by the acceleration force when the other axis operates Since the rolling force of the portion balances with the moment force generated around the center of gravity at the fulcrum of the leaf spring, crosstalk does not occur, thereby improving drive control.

In the invention according to claim 2, in the invention according to claim 1, since the centers of gravity of the first movable part and the second movable part are made to coincide with each other, the reaction force acting on the action points of all the leaf springs is the center of gravity. Since it passes, the moment force around the center of gravity is not generated, and the rolling phenomenon is not generated in both the movable parts, whereby the accuracy of drive control can be improved.

According to a third aspect of the present invention, in the first aspect of the invention, the first fulcrum and the first action point of the first leaf spring are included.
A first movable plane in the direction of the first protrusion passing through the center of gravity of the first movable portion, a second fulcrum and a second point of action of the second leaf spring, and a direction of the second protrusion passing through the center of gravity of the second movable portion. Since the second movable plane is made coincident with the second movable plane, it is not excited by the higher-order resonance due to the interference of the other axis, so that the accuracy of drive control can be improved.

According to a fourth aspect of the invention, in the invention of the first aspect, the first leaf spring surface excluding the first fulcrum and the first action point of the first leaf spring and the second fulcrum of the second leaf spring and Since the damper member is provided on each of the second leaf spring surfaces excluding the second action point, the hysteresis during movement can be reduced, so that the accuracy of drive control can be improved.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the magnetic gaps of the first magnetic circuit and the second magnetic circuit for generating the driving force in each movable direction are formed on the bottom surface of the base. Since they are arranged parallel to each other, the magnetic gap for generating the driving force is parallel to the base independently of the two axes, so that the magnetic flux density becomes uniform, the driving sensitivity is stabilized, and the accuracy of driving control is improved. And again,
As a result, the magnetic gap can be narrowed and the size can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing the configuration of a biaxial actuator that is an embodiment of the present invention.

FIG. 2 is a schematic view showing a force relationship acting on a movable portion.

FIG. 3 is a characteristic diagram showing biaxial frequency characteristics.

FIG. 4 is a characteristic diagram showing a state of displacement sensitivity of a movable part with respect to a coil current.

FIG. 5 is an optical path diagram showing an operation principle of optical axis control.

[Explanation of symbols]

 8 corner cube 9 1st holder 10 1st protrusion part 11 1st leaf spring 12 1st point of action 13 1st coil 15 1st fulcrum 17 2nd holder 18 1st side surface 19 1st movable part 20 1st magnetic circuit 21st 2 side surface 22 2nd projection part 23 2nd leaf spring 24 2nd action point 25 2nd coil 27 2nd fulcrum 29 2nd movable part 30 2nd magnetic circuit 31 base 31a bottom face part 31b 3rd side surface 32,33 damper member

Claims (5)

[Claims] 1. A first holder that holds a corner cube and has a first protrusion formed to project in a uniaxial direction, a first leaf spring that supports the first protrusion at a first point of action, and a first leaf spring. A first movable part including a first coil connected to the first holder via a first leaf spring; a first magnetic circuit arranged in the same direction as the axis of the first movable part; A second holder including a first holder therein and fixing the first leaf spring to the first side surface at a first fulcrum, and at the same time having a second protrusion formed to project from a second side surface orthogonal to the first side surface; A second movable portion including a second leaf spring that supports the second protrusion at the second point of action and a second coil connected to the second holder via the second leaf spring, and a second movable portion. A second magnetic circuit arranged in the same direction as the axis of the movable part, and the second leaf spring. Is a base having a third side surface fixed at a second fulcrum and a bottom surface part on which the second holder is installed. 2. The biaxial actuator according to claim 1, wherein the centers of gravity of the first movable portion and the second movable portion are made coincident with each other. 3. A first fulcrum and a first point of action of the first leaf spring, a first movable plane in the direction of the first protrusion that passes through the center of gravity of the first movable portion, a second fulcrum of the second leaf spring, and 2. The biaxial actuator according to claim 1, wherein the second action point and the second movable plane in the direction of the second protrusion that passes through the center of gravity of the second movable portion are made to coincide with each other. 4. A first leaf spring surface excluding the first fulcrum and the first action point of the first leaf spring and a second leaf spring surface excluding the second fulcrum and the second action point of the second leaf spring. The biaxial actuator according to claim 1, wherein each of the damper members is provided. 5. The magnetic gap of each of the first magnetic circuit and the second magnetic circuit for generating a driving force in each movable direction is arranged so as to be parallel to the bottom surface portion of the base. The biaxial actuator according to 1.