JPH07105552A - Biaxial actuator for optical pickup device - Google Patents

Abstract

PURPOSE:To miniaturize a device and to make driving efficiency excellent by contriving positional relation between the tracking coil or the focusing coil of a biaxial actuator and a magnet. CONSTITUTION:This actuator is provided with the tracking coil 24 wound round so that the directions of currents flowing to two opposed sides (the left side of the tracking coil and the right side of the tracking coil) 24l and 24r may be opposite, and the magnet 7 oppositely arranged to the tracking coil. Then, it is magnetized so that the polarity of the magnet may be different between parts opposed to two sides of the tracking coil (the left side front surface of the magnet and the right side front surface of the magnet) 7l and 7rf.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel biaxial actuator for an optical pickup device. More specifically, it is possible to provide a novel biaxial actuator of an optical pickup device which can be miniaturized by devising a positional relationship between a tracking coil or a focusing coil of a biaxial actuator and a magnet and which can improve driving efficiency. It is what

[0002]

2. Description of the Related Art In a biaxial actuator of an optical pickup device, it is common that one or a plurality of tracking coils and / or focusing coils each have a magnet whose opposite surface is magnetized to have a single pole. Met.

12 to 14 show an example a of a biaxial actuator of a conventional optical pickup device.

The biaxial actuator a has a rectangular, slightly thick plate-shaped base substrate b, and four parallel links whose one end is supported by a printed circuit board c protruding from one end of the base substrate b. , and the parallel links d, d,
A lens holding member f that is supported between the free ends of the lens holder and holds the objective lens e, a focusing coil g and tracking coils h and h for an actuator attached to the lens holding member f, and the base described above. U mounted on the substrate b and arranged so as to sandwich the focusing coil g and the tracking coils h and a part of the h from both sides.
It is composed of a yoke i in the shape of a letter and a magnet j and the like attached to the yoke i.

The base substrate b is made of a non-magnetic material, and a through hole k is formed at the other end portion in the longitudinal direction.

The parallel links d, d, ... Are made of a conductive metal material, support the lens holding member f as described above, and have a predetermined circuit pattern on the printed circuit board c and the focusing coil g and the focusing coil g. The tracking coils h and h are electrically connected to each other to supply power to the focusing coil g and the tracking coils h and h.

The lens holding member f is made of a non-magnetic material in the shape of a slightly thick rectangular plate, and the objective lens e is supported at a position near the other end of the lens holding member f in the longitudinal direction. A rectangular hole 1 having a relatively large opening is formed substantially in the center thereof.

Further, such a lens holding member f has 4
While being supported by the printed circuit board c via parallel links d, d, ... of the book, the objective lens e is positioned substantially parallel to the base substrate b, and the objective lens e is formed in the through hole k of the base substrate b. And two pieces (hereinafter, referred to as “inner yoke” and “outer yoke”, respectively) m and n of the yoke i which are located above each other and are opposed to each other, with a margin in the rectangular hole l. Is located. In the yoke i, the printed circuit board c
The piece on the side is the inner yoke m, and the piece on the side of the objective lens e is the outer yoke n.

The yoke i is a plate-shaped member made of magnetic material.
It is formed by bending it into a letter shape, and is formed so as to open upward in the substantially central portion of the base substrate b, and the inner yoke m
The outer yoke n and the outer yoke n are arranged so as to be separated from each other in the longitudinal direction of the base substrate b.

The magnet j is attached to the inner side surface of the inner yoke m, and the surface of the magnet j facing the outer yoke is magnetized into a single pole. Therefore, the magnet j-the inner yoke m-the inner yoke m and the outer side. A magnetic circuit called a connection part with the yoke n-the outer yoke n-the gap between the outer yoke n and the magnet j-the magnet j is formed, and the direction of the magnetic flux in the magnetic field o generated between the magnet j and the outer yoke n is Only in one direction.

The focusing coil g is formed by winding a copper wire in a rectangular tube shape, and three of four sides in a plan view have three sides out of the inner peripheral surface of the rectangular hole l of the lens holding member f, the objective lens e. Is attached to the inner surface excluding the inner surface on the side, whereby one side p of the focusing coil g on the side of the objective lens e is positioned so as to bridge the two surfaces of the rectangular hole 1 facing each other. Are located in the magnetic field o.

The tracking coils h, h are formed by winding a copper wire in a rectangular spiral shape, and are arranged laterally on the outer surface of the side p of the focusing coil g located in the magnetic field o. Only one side q, q of the adjacent sides of each tracking coil h, h is attached so as to face the magnet j, so that the two adjacent sides q, q of the two tracking coils h, h have the above-mentioned magnetic field. It is designed to be located within o. Further, the above-mentioned one sides q and q of the tracking coils h, h are the tracking coils h, h
The current flows in the same direction when power is supplied to.

FIG. 14A shows the positional relationship between the one side p of the focusing coil g and the magnet j, and FIG.
4 (b) is the above-mentioned one side q, q of the tracking coil h, h
3 shows the positional relationship between the magnet and the magnet j.

However, when power is supplied to the focusing coil g, a moving force that moves upward or downward depending on the direction of the current is generated between the one side p of the focusing coil g positioned in the magnetic field o and the magnet j. As a result, the lens holding member f is moved in the vertical direction (focusing direction) with respect to the base substrate b.

When the tracking coils h, h are fed with power, the tracking coils h, h positioned in the magnetic field o are left between the one side q, q of the tracking coil h and the magnet j, or the left side or the direction depending on the direction of the current. A moving force to the right occurs,
This allows the lens holding member f to move in the horizontal direction (tracking direction) with respect to the base substrate b.

[0016]

However, in the biaxial actuator a of the above-mentioned conventional optical pickup device, the surface of the magnet j facing each coil g, h, h has a single pole, and , The coils g, h, h located in the magnetic field o are only some of them (the above-mentioned one side p, q, q), and the other three sides are not in the magnetic field o, so the other three sides have driving force. There is a problem that the driving efficiency is poor because it is an ineffective conductor portion that does not contribute to.

If the driving efficiency of the biaxial actuator a is poor, stability will be lost unless the driving voltage of the biaxial actuator a is increased, and the operation of the biaxial actuator will become unstable even with a slight voltage drop. .

The fact that the coils g, h, h have many ineffective conductor portions makes it impossible to downsize the biaxial actuator a, and the movable portion of the biaxial actuator a (mainly the lens holding member f The objective lens e, the focusing coil g, and the tracking coils h, h) are heavy and the response characteristics are poor.

Further, each coil g, h, h of the magnet j is
Since the surface facing to is a single pole and the direction of the magnetic flux is one direction, in order to pass all the magnetic flux (total magnetic flux) emitted from the magnet j from the inner yoke m to the outer yoke n, There is a problem in that the magnetic flux density becomes supersaturated unless the cross-sectional area taken in the direction orthogonal to the magnetic flux is increased, that is, the wall thickness is increased, and eventually miniaturization cannot be achieved.

[0020]

Therefore, in order to solve the above-mentioned problems, the biaxial actuator of the optical pickup device of the present invention is wound so that the directions of the currents flowing in the two opposite sides are opposite to each other. A focusing coil or a tracking coil and a magnet opposed to the focusing coil or the tracking coil are provided, and the polarities of the magnet are made different at the portions facing the two sides of the focusing coil or the tracking coil, respectively. .

[0021]

Therefore, according to the optical pickup device of the present invention, since the magnets are made to face two opposite sides of the focusing coil or the tracking coil, respectively, a portion which is not located in the magnetic field of the focusing coil or the tracking coil, That is, it is possible to reduce the invalid conductor portion that does not contribute to the driving force,
As a result, it is possible to improve the driving efficiency, stabilize the operation of the biaxial actuator, and
The size can be reduced.

Further, since the number of invalid conductor portions can be reduced as much as possible, the conductor utilization efficiency is good, the movable portion of the biaxial actuator can be made light, and the response characteristics of the biaxial actuator can be improved. it can.

Further, since the polarities of the portions of the respective coils of the magnet facing the two sides facing each other are different, two magnetic fields having different magnetic flux directions are formed between the magnet and the outer yoke. The number of magnetic fluxes in the inner and outer yokes is about half compared to the case where a magnet with the same magnitude and facing the coils is magnetized to a single pole (conventional one). Therefore, the thickness of the yoke and the outer yoke can be reduced, and the size can be reduced.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the biaxial actuator of the optical pickup device of the present invention will be described below with reference to the embodiments shown in the accompanying drawings.

In the first embodiment, magnets having different polarities are respectively provided on two sides (two sides extending in the vertical direction) of the tracking coil wound in one rectangle and facing each other substantially in parallel. It is placed separately.

The biaxial actuator 1 includes a base substrate 2 made of a magnetic metal material, a lens holding member 5 that holds an objective lens 3 and is supported by the base member 2 via parallel links 4, 4 ,. It comprises a yoke 6 formed on the base substrate 2, a magnet 7 attached to the yoke 6, a coil substrate 8 supported by the lens holding member 5, and the like.

The base substrate 2 has a plane shape and a substantially rectangular shape.
The front edge is located at a position closer to both sides of the front end (the direction diagonally downward to the right in FIG. 1 is the front side, the direction diagonally upward to the left is the rear side, and the direction diagonally upward to the right is the left side, and , The direction diagonally downward to the left is the right side.
In the following description, the direction is used when indicating the direction. ) Is formed with two slits, and a portion between these two slits is cut and raised to form the outer yoke 9 of the yoke 6, and the outer yoke 9 and the base substrate 2 are formed. A slit is formed in a U-shape in the direction between the rear end edge and the outer yoke 9 side,
An inner yoke 10 of the yoke 6 is formed by cutting and raising a portion surrounded by the slits, and an appropriate gap is formed between the outer yoke 9 and the inner yoke 10.

The magnet 7 is in the shape of a horizontally long rectangular plate, and different poles are magnetized in the longitudinal direction and the front and back sides thereof. That is, the front surface (anti-yoke attachment surface) 7lf of the left side portion 7l of the magnet 7 and the right side portion 7 of the magnet 7
The rear surface (yoke attachment surface) 7rb of r is, for example, the N pole, and the front surface (anti-yoke attachment surface) 7rf of the right side portion 7r of the magnet 7 and the back surface (yoke attachment surface) of the magnet 7 are attached. The surface 7 lb is magnetized so as to be the S pole, and such a magnet 7 is attached to the surface of the inner yoke 10 facing the outer yoke 9, whereby the left magnet portion 7 l-the left magnet portion 7l and the left portion of the outer yoke 9 -the left portion of the outer yoke 9 -the right portion of the outer yoke 9 -the gap between the right portion of the outer yoke 9 and the magnet right portion 7r -the magnet right portion 7
r-a right side portion of the inner yoke-10-a left side portion of the inner yoke-10-a magnet left side portion 7l, a magnetic circuit is formed,
Two magnetic fields 11l and 11r having different magnetic flux directions are generated between the magnet 7 and the outer yoke 9 on the left side and the right side thereof.

As a result, the inner yoke 10 and the outer yoke 9 are
The number of magnetic fluxes inside is approximately half compared to the case where a magnet of the same size that is not divided into two poles is attached (conventional one), and therefore the thickness of the yoke 10 and the outer yoke 9 is reduced. be able to.

The magnet 7 is magnetized so that one magnetic body has different polarities on the front and back sides, and also has different polarities in the length direction. Two magnets having different polarities may be arranged side by side so that their polarities are different in the plane direction.

Reference numeral 12 denotes a biaxial holder which is erected at the rear end of the base substrate 2 and has a horizontally long rectangular plate shape made of an insulating material, and slits extending in the vertical direction at positions near the left and right ends thereof. 12a, 12a are formed so as to open at the upper end thereof.

The parallel links 4, 4, ... Are made of conductive metal wires and are planted at the four corners of a rectangular printed circuit board 13. The printed circuit board 13 has four parallel links 4, 4 ,. ... is a biaxial holder 1 with the direction extending forward
It is attached so as to be attached to the back surface of 2.

The parallel links 4, 4, ... Are passed through the slits 12a, 12a of the biaxial holder 12 and the slits 12a, 12a are filled with an adhesive so that the biaxial holder 12 is Supported.

The lens holding member 5 has a plate shape made of an insulating material, and the rear half of the lens holding member 5 has a substantially rectangular shape in a plan view, and the left and right side edges of the front half of the lens holding member 5 deviate toward the center as they go forward. It has a shape, a rectangular hole 14 which is long in the left-right direction is formed in the substantially central portion, and the objective lens 3 is supported at the front end portion.

Rectangular hole 14 formed in the lens holding member 5
Has a size larger than the planar shape of the outer yoke 9, the inner yoke 10, the magnet 7, and the gap between the outer yoke 9 and the magnet 7, and the lens holding member 5 has the parallel link. The outer yoke 9 and the inner yoke 10 are accommodated in the rectangular hole 14 while being supported by 4, 4 ,.
And the magnet 7 is positioned.

The lens holding member 5 as described above is formed such that the entire thickness thereof is smaller than the distance between the vertically spaced apart parallel links 4, 4, ... The part of the left and right sides of the parallel link 4 which is closer to the front side is thicker than the other parts, and the parallel links 4 are spaced above and below.
And the rectangular holes 1
A portion 15 on the rear side of 4 which is slightly narrower than the space between the parallel links 4 and 4 which are spaced apart from each other on the left and right sides is formed thickly downward.

The thick portions on both sides of the rectangular hole 14 are the supported portions 16, 16 to which the tips of the parallel links 4, 4, ... Are joined, and the rear side of the rectangular hole 14 is also connected. The thick portion 15 is a balancer portion for balancing the weight of the lens holding member 5. The balancer unit 15 is
As will be described later, the size thereof is determined so that the center of gravity of the lens holding member 5 and the drive center of the coil substrate 8 coincide with each other.

Reference numerals 17 and 17 denote notches formed by notching the portions of the rectangular hole 14 corresponding to the supported portions 16 and 16 in the vertical direction.

The coil board 8 has a substantially rectangular shape and is formed such that its four corners are obliquely cut out, and further, both left and right edges are slightly projected leftward and rightward to form mating portions 18, 18. The fitted portions 18, 18 are the cutout portions 1 of the rectangular hole 14.
The coil board 8 is positioned in the rectangular hole 14 by being fitted into the fitting holes 7, 17, and in this state, the fitted parts 18, 18
The upper and lower end edges of the are positioned so as to slightly project upward or downward from the upper surface or the lower surface of the supported portions 16, 16.

The coil board 8 is formed by stacking four thin printed boards 8a, 8b, 8c and 8d, and each thin printed board 8a, 8b, 8c and 8d has a focusing coil element 19, 19 ,. .. and the tracking coil elements 20, 20, ... Are formed as a circuit pattern.

The four printed boards 8a, 8b, 8
Since the circuit patterns formed on c and 8d are formed in substantially the same shape, only one printed board 8a will be described, and description of the other printed boards 8b, 8c, and 8d will be omitted.

A tracking coil element 20 is formed by forming a circuit pattern so as to wind a vertically long rectangular vortex in the central portion of the thin printed board 8a, and the four corners are formed so as to surround the tracking coil element 20. The focusing coil element 1 has a circuit pattern formed so that a spiral is swirled in such a shape that a corner portion of a rectangle is obliquely cut.
, Are formed, and these four focusing coil elements 19, 19, ... Are arranged so as to be point-symmetric with respect to the center of the thin printed board 8a.

.. are thin-walled printed circuit boards 8
Focusing coil elements 19, 19, ... Or tracking of one thin printed circuit board 8 when four thin printed circuit boards 8a, 8b, 8c, 8d are superposed on each other. Coil element 20
, And other focusing coil elements 19, 19, ... Or tracking coil element 20 of the thin printed circuit board 8 are respectively connected.

Reference numerals 22 and 22 denote power supply terminals formed by a circuit pattern at the upper end and the lower end of the thin printed circuit board 8a at positions corresponding to the fitted portion 18 on the left side.
This is for supplying power separately to the focusing coil 23 and the tracking coil 24. In addition, this power supply terminal 2
2 and 22 are formed only on the first-layer thin-walled printed circuit board 8a and the fourth-layer thin-walled printed circuit board 8d. As the coil substrate 8, two feeding terminals 22au (for the first layer) for the focusing coil 23 are provided. The left side of the thin printed circuit board 8a) and 22du (the upper side of the right side of the fourth layer thin printed circuit board 8d) are also used for the tracking coil 20.
Two power supply terminals 22ad (thin-layer thin printed circuit board 8a
Lower part) and 22dd (the lower part on the right side of the thin printed circuit board 8d of the fourth layer) are formed.

Such thin printed circuit boards 8a, 8b,
8c, 8d are overlapped to form the coil substrate 8,
Further, each focusing coil element 19, 19, ...
Alternatively, the tracking coil elements 20, 20, ... Are plated on the through holes 21, 21, .. so that electrical connection is achieved, whereby the focusing coil elements 19, 19 ,. Two focusing coils 23, and also tracking coil elements 20, 20 ,.
.. constitute one tracking coil 24.

The lens holding member 5 to which such a coil substrate 8 is attached is positioned so that the supported portions 16, 16 thereof are sandwiched between the tips of the parallel links 4, 4 which are vertically opposed to each other. 4, 4 ..., and the coil substrate 8
The upper and lower edges of both fitted parts 18, 18 are respectively joined by soldering, whereby the power supply terminals 22, 22, ... Formed on the coil substrate 8 and the parallel links 4, 4 ,. .. are electrically connected to each other, and the lens supporting member 5 is connected to the coil substrate 8 by soldering on the supported portions 16, 16, and the parallel links 4, 4 ,. It is attached between the tips and is supported movably in the vertical and horizontal directions with respect to the base substrate 2.
The coil substrate 8 is provided with the notches 17 and 1 of the lens holding member 5.
It may be attached to No. 7 with an adhesive in advance.

With the lens holding member 5 supported by the base substrate 2 via the parallel links 4, 4, ..., The coil substrate 8 is located between the magnet 7 and the outer yoke 9, that is, Magnet 7 and outer yoke 9 in the magnetic field 11
It is positioned so that it does not come into contact with.

Further, the lens holding member 5 has the focusing coil 2 when no external force is applied thereto.
Lower part 23l of the part 23lu located in the upper left of 3
ud and the upper part 23l of the lower left part 23ld
du and the left side portion 24l of the tracking coil 24 face the front surface 7lf of the left side portion 7l of the magnet 7,
Further, the lower part 23rud of the focusing coil 23, the upper part 23rdu of the lower part 23ru and the upper part 23rdu of the lower right part 23rd, and the right part 24r of the tracking coil 24 are the front surface 7rf of the left part 7r of the magnet 7. (Fig. 8)
reference).

When power is supplied to the focusing coil 23, the lower portion 23lu of the focusing coil 23 located at the upper left and the upper portion 23ldu of the lower left portion 23ld in the same direction,
For example, a current flows leftward, and the lower part 23rud of the upper part 23ru of the focusing coil 23 and the upper part 23rdu of the lower right part 23rd of the focusing coil 23 are the left parts 23lud and 23ld.
A current flows in the direction opposite to u, that is, to the right, and these magnets 7 face each other.
Since the polarities of l and 7r are different, a moving force is generated in the same direction as the coil substrate 8, and the lens holding member 5 is moved in the vertical direction, that is, the focusing direction with respect to the base substrate 2.

When power is supplied to the tracking coil 24, current flows in different directions in the left side portion 24l and the right side portion 24r of the tracking coil 24, but the left side portion 24l and the right side portion 24r are different from each other. Since it faces the polar magnets 7l and 7r,
A moving force is generated in the same direction as the coil substrate 8, and the lens holding member 5 is horizontal to the base substrate 2, that is,
It will be moved in the tracking direction.

Further, the center of the driving force generated by supplying power to the focusing coil 23 and the center of the driving force generated by supplying power to the tracking coil 24 are such that the coils 23 and 24 are substantially on the same plane and each of them is a coil. Since they are formed point-symmetrically with respect to the center of the substrate 8, they are substantially at the same point, and the drive center is the same in the movement in the focusing direction and the movement in the tracking direction.
Further, since the driving center thereof is substantially the center of gravity of the coil substrate 8, the size of the balancer portion 15 is determined so that the center of gravity of the entire lens holding member 5 coincides with the center of gravity of the coil substrate 8. The operation of the holding member 5 can be stabilized.

Therefore, according to the first embodiment, only the upper part and the lower part of the tracking coil 24 are made into invalid conductor parts, and most of the tracking coils 24 are made into effective conductor parts, and the moving force in the tracking direction is reduced. Can contribute to the generation.

FIGS. 9 to 11 show a second embodiment 1A of the biaxial actuator of the optical pickup device of the present invention. The difference of the second embodiment from the first embodiment is as follows. Only the shapes of the focusing coil and the tracking coil on the coil substrate, the polarities of the magnets, and the positional relationship between them are shown. Therefore, with respect to the second embodiment 1A, the same parts as those of the biaxial actuator 1 are designated by the same reference numerals as those of the biaxial actuator 1 and the description thereof will be omitted.

In the second embodiment 1A, the polarities of the portions of the focusing coil wound in a rectangular shape and facing the two sides (two sides extending in the horizontal direction) that are substantially parallel to each other (two sides extending in the horizontal direction) are different from each other. It is a pair of different magnets.

Reference numeral 25 denotes a coil substrate, which is formed by stacking four thin printed circuit boards on top of each other as in the case of the first embodiment. The focusing coil element and the tracking coil element are formed by the circuit pattern of each thin printed circuit board. Since the shapes are substantially the same, the thin printed circuit board 25a of the first layer
Only the thin printed circuit board of the other layers will be omitted.

26 is a focusing coil element,
The thin printed circuit board 25a is formed in a circuit pattern so as to make a spiral in a square shape at a substantially central portion thereof.

Denoted by 27, 27, ... are tracking coil elements, which have different shapes in which one side of the rectangle is arcuate at the four sides above and below the left and right sides of the focusing coil element 26 of the thin printed circuit board 25a. The tracking coil 27 is formed by a circuit pattern so as to swirl, and the arc-shaped sides of each tracking coil 27 are located on the left and right outside, and the sides facing the sides are the left and right sides of the focusing coil element 16 (sides extending in the vertical direction). ) Is adjacent to. Further, these four tracking coil elements 27, 27, ... Are arranged so as to be point-symmetric with respect to the center of the thin printed board 25a.

The four thin printed boards are stacked to form the coil board 8, and the focusing coil elements 26, 26, ... Or the tracking coil elements 27, 27 ,. Two
.. are plated to achieve electrical connection, which allows the focusing coil elements 26, 26, ...
. Constitutes one focusing coil 28, and tracking coil elements 27, 27, ... Compose one tracking coil 29.

The magnet 30 is in the shape of a horizontally long rectangular plate, and the different poles are magnetized in the up-down direction and the front and back sides thereof, that is, the front surface (anti-yoke attachment surface) 30uf of the upper portion 30u of the magnet 30. The back surface (yoke attachment surface) 30db of the lower portion 30d of the magnet 30 is, for example, the N pole, and the front surface (anti-yoke attachment surface) 30df of the lower portion 30d of the magnet 30 and the upper portion of the magnet 30. The back surface of 30u (the surface to which the yoke is attached) 30ub is magnetized so as to be the S pole.
0 is affixed to the surface of the inner yoke 10 facing the outer yoke 9, so that the gap between the magnet upper portion 30u and the magnet upper portion 30u and the upper portion of the outer yoke 9-the upper portion of the outer yoke 9- Lower part of outer yoke-9-Gap between lower part of outer yoke 9 and lower magnet part 30d-Lower magnet part 30d-Lower part of inner yoke-10-Upper part of inner yoke-10-Upper magnet part30u That is, a magnetic circuit is formed, and two magnetic fields 31u and 31d having different magnetic flux directions are generated between the magnet 7 and the outer yoke 9 on the upper side and the lower side thereof.

As a result, the inner yoke 10 and the outer yoke 9 are
The number of magnetic fluxes inside is approximately half compared to the case where a magnet of the same size that is not divided into two poles is attached (conventional one), and therefore the thickness of the yoke 10 and the outer yoke 9 is reduced. be able to.

When the lens holding member 5 has no external force applied thereto, the tracking coil 2
The right part 29l of the part 29lu located in the upper left of 9
ur and the left side portion 29r of the portion 29ru located at the upper right
ul and the upper part 28 of the focusing coil 28
u is the front surface 30uf of the upper portion 30u of the magnet 30.
The right side portion 29ldr of the lower left portion 29ld of the tracking coil 29 and the left side portion 29rdl of the lower right portion 29rd of the tracking coil 29 and the lower portion 28d of the focusing coil 28 are below the magnet 30. It is adapted to face the front surface 30df of the side portion 30d (see FIG. 10).

When the tracking coil 29 is supplied with power, the right side portion 29lu of the upper left portion 29lu and the left side portion 29ru of the upper right portion 29ru of the tracking coil 29 are directed in the same direction, for example, upward. A current flowing therethrough, and the right side portion 29 of the lower left portion 29ld of the tracking coil 29
Left part 29r of ldr and the part 29rd located at the lower right
A current flows in a direction opposite to that of the upper portions 29lur and 29rul, that is, in a downward direction, to dl, and these magnets 30u and 3u face each other.
Since the polarities of 0d are different, a moving force is generated in the same direction as the coil substrate 25, and the lens holding member 5 is moved in the left-right direction with respect to the base substrate 2, that is, the tracking direction.

When power is supplied to the focusing coil 28, current flows in different directions in the upper portion 28u and the lower portion 28d of the focusing coil 28, but the upper portion 28u and the lower portion 28d respectively Since the magnets 30u and 30d having different polarities face each other, a moving force in the same direction is generated as the coil substrate 25, and the lens holding member 5 is moved in the vertical direction with respect to the base substrate 2, that is, the focusing direction. Will be.

Therefore, according to the second embodiment, according to the second embodiment, only the left side portion and the right side portion of the focusing coil 28 are the invalid conductor portions, and most of the focusing coil 28 is effective. The conductor portion can contribute to the generation of a moving force in the focusing direction.

[0065]

As is apparent from the above description, the biaxial actuator of the optical pickup device of the present invention has two sides facing each other substantially in parallel, and the directions of the currents flowing through these two sides are opposite. Focusing coil or tracking coil wound so as to form a magnet, and a magnet opposed to the focusing coil or tracking coil, the polarities of the magnets facing the two sides of the focusing coil or tracking coil, respectively. It is characterized in that the parts are made different.

Therefore, according to the optical pickup device of the present invention, since the magnets are made to face two opposite sides of the focusing coil or the tracking coil, respectively, a portion which is not located in the magnetic field of the focusing coil or the tracking coil, That is, it is possible to reduce the number of ineffective conductor portions that do not contribute to the driving force, which can improve the driving efficiency.
The operation of the shaft actuator can be stabilized, and the size can be reduced.

Further, since the number of ineffective conductors can be reduced as much as possible, the conductor utilization efficiency is good, the movable part of the biaxial actuator can be made light in weight, and the response characteristics of the biaxial actuator can be improved. it can.

Further, since the polarities are made different in the portions of the respective coils of the magnet that face two opposite sides, the two magnetic fields having different magnetic flux directions are formed between the magnet and the outer yoke. The number of magnetic fluxes in the inner and outer yokes is about half compared to the case where a magnet with the same magnitude and facing the coils is magnetized to a single pole (conventional one). Therefore, the thickness of the yoke and the outer yoke can be reduced, and the size can be reduced.

In each of the above embodiments, the focusing coil and the tracking coil are formed by forming a circuit pattern on the printed board, but the present invention is not limited to this, and a copper wire is wound in a rectangular spiral shape. A focusing coil and / or a tracking coil may be formed, and the point is that the polarities of the magnets are made different at the portions facing the two sides of the coil that are substantially parallel to each other.

Further, the specific shapes and structures of the respective parts shown in the above-mentioned respective embodiments are merely examples of the realization in the implementation of the biaxial actuator of the optical pickup device of the present invention. The technical scope of the present invention should not be limitedly interpreted.

[Brief description of drawings]

1 shows a first embodiment of a biaxial actuator of an optical pickup device of the present invention, together with FIG. 2 to FIG.
This figure is a perspective view.

FIG. 2 is a plan view.

3 is a cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a front view of the printed circuit board of the first layer, showing each coil element by a circuit pattern formed on the thin printed circuit board of each layer together with FIG. 5 to FIG.

FIG. 5 is a front view of a second-layer printed circuit board.

FIG. 6 is a front view of a third-layer printed circuit board.

FIG. 7 is a front view of a fourth-layer printed circuit board.

FIG. 8 is a schematic diagram showing a positional relationship between each coil and a magnet.

9 shows a second embodiment of the biaxial actuator of the optical pickup device of the present invention, together with FIG. 10 and FIG. 11, and is a central longitudinal sectional view.

FIG. 10 is a front view of a first-layer printed circuit board.

FIG. 11 is a schematic view showing a positional relationship between each coil and a magnet.

FIG. 12 is a plan view showing an example of a biaxial actuator of a conventional optical pickup device.

13 is a sectional view taken along line XIII-XIII in FIG.

14A and 14B are schematic diagrams showing a positional relationship between each coil and a magnet, FIG. 14A shows a relationship between a focusing coil and a magnet, and FIG. 14B shows a relationship between a tracking coil and a magnet. .

[Explanation of symbols]

1 2-axis actuator 7 Magnet 7lf Front left side of magnet (portion where different poles are magnetized) 7rf Front right side magnet (portion where different pole is magnetized) 24 Tracking coil 24l Left side of tracking coil (two facing each other) Side 24r Right side of tracking coil (two opposite sides) 1A Biaxial actuator (second embodiment) 28 Focusing coil 28u Upper side of focusing coil (two opposite sides) 28d Lower side of focusing coil (relative) Two sides facing each other) 30 magnet 30uf Upper front surface of magnet (portion where different poles are magnetized) 30df Lower front surface of magnet (portion where different poles are magnetized)

Claims (1)

[Claims] 1. A focusing coil or tracking coil having two sides that are substantially parallel to each other and wound so that the directions of currents flowing through these two sides are opposite, and the focusing coil or the tracking coil. A pair of magnets arranged opposite to each other, the polarities of the magnets being different at portions of the focusing coil or the tracking coil which face the two sides, respectively.
Axis actuator.