JP3383029B2 - Optical pickup device - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a novel optical pickup.
Regarding the device . Specifically, the shape and arrangement position of the tracking coil and the focusing coil of the biaxial actuator should be devised to reduce the size and to shorten the gap between the magnet and the outer yoke, that is, the magnetic field to improve the driving efficiency. A new optical pickup that can
It is intended to provide a device .

[0002]

A tracking coil and a focusing coil in a biaxial actuator of an optical pickup device are generally formed by winding a copper wire.

9 and 10 show an example of a biaxial actuator a 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 which holds the objective lens e and which is supported between the turning ends, a focusing coil g and tracking coils h and h for the actuator, which are attached to the lens holding member f, A U-shaped yoke i attached to the base substrate b and arranged so as to sandwich a part of the focusing coil g and the tracking coils h from both sides, and a magnet j attached to the yoke i. Etc.

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 form of a substantially thick rectangular plate, and the objective lens e is attached to a position near the other end edge of the lens holding member f in the longitudinal direction. Further, 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 facing each other are located in the rectangular hole 1 with a margin. In the yoke i, the piece on the printed circuit board c side is the inner yoke m, and the piece on the objective lens e side is the outer yoke n.
Is.

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, whereby the magnet j and the outer yoke n are attached.
A magnetic field o is formed between and.

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 of the inner peripheral edge of the rectangular hole 1 of the lens holding member f on the side of the objective lens e. The inner side of the focusing coil g is affixed from the inner side except the inner side, and one side 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.

The tracking coils h, h are formed by winding a copper wire in a rectangular spiral shape, and are attached to the outer surface of one side of the focusing coil g which is not attached to the inner peripheral edge of the rectangular hole l, and two tracking coils are provided. The coils h, h are arranged side by side in the lateral direction.

In such a biaxial actuator a, the lens holding member f is vertically (focusing direction) or horizontally (tracking) with respect to the base substrate b by supplying power to the focusing coil g or the tracking coils h, h. Direction).

[0014]

However, in the biaxial actuator a of the above-mentioned conventional optical pickup device, the focusing coil g and the tracking coils h, h are formed by winding a copper wire. Since the tracking coil h has a certain thickness and the tracking coils h are superposed on the outer surface of the focusing coil g, the gap between the magnet j and the outer yoke n must be increased, and the magnetic field o There is a problem that it becomes long and the driving efficiency is poor.

When the driving efficiency of the biaxial actuator a is low, the sensitivity of the biaxial actuator a is lowered, which causes problems such as an increase in power consumption of the biaxial actuator and unstable vibration resistance .

Further, since the focusing coil g is formed by winding it into a rectangular tube shape, only one of the four sides is positioned in the magnetic field o, and the ineffective conductor portion is The efficiency of using many conductors is low and the biaxial actuator a cannot be downsized, and in particular, the movable portion (mainly the lens holding member f, the objective lens e, and the like of the biaxial actuator a,
Focusing coil g and tracking coil h,
There was a problem that the weight of h) became heavy and the response characteristics were poor.

Further, since the focusing coil g and the tracking coils h, h are superposed in the extending direction of the parallel links d, d, ..., The respective driving action points are displaced in the superposing direction, and the driving center And the center of gravity of the movable part 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) cannot be matched, and the operation of the movable part is not stable. There's a problem.

Furthermore, since the tracking coils h, h are superposed on the outer surface of the focusing coil g,
There is a problem in that variations in characteristics occur among the finished products due to the overlay error.

[0019]

In order to solve the above-mentioned problems, the optical pickup device of the present invention has a lens holder holding an objective lens, an elastic member for supporting the lens holder, and a fixed portion side. A single plate-shaped magnet provided and a pair of flat-plate-shaped yokes facing the magnet, and while being attached to the lens holder,
It is disposed between the magnet and the yoke, the printed circuit board thickness
Circuit patterns on the same plane so that they do not overlap in the vertical direction.
And a pair of plate-shaped focusing coil and tracking coils which are formed as over emissions, in the magnet
The tracking coil is placed at the position corresponding to the center
Along with each of the magnets on both sides of the tracking coil
Focusing coils corresponding to the magnetic poles are arranged
Connect the N pole of the net to one side of the tracking coil
Corresponding to the coil side of each focusing coil
Together with the S pole of the magnet, the other side of the tracking coil
Coil side of the other focusing coil
It corresponds to .

[0020]

Therefore, according to the optical pickup device of the present invention, since the focusing coil and the tracking coil are formed on the same plane as the circuit pattern on the printed circuit board, the focusing coil and the tracking coil can be thinned and the magnet and Gap with the yoke,
That is, the length of the magnetic field can be shortened, and
The driving efficiency can be improved, the operation of the biaxial actuator can be stabilized, and the size can be reduced.

Further, since the focusing coil and the tracking coil are formed as a circuit pattern on the printed circuit board, the number of ineffective conductor portions is small and the conductor utilization efficiency is good, which makes it possible to reduce the weight of the movable portion of the biaxial actuator. The response characteristics of the biaxial actuator can be improved.

Further, since the focusing coil and the tracking coil are formed on the same plane, the driving action points do not deviate from each other, and the driving center and the center of gravity of the movable portion of the biaxial actuator can be matched. A stable operation of the movable part can be obtained.

Furthermore, since the focusing coil and the tracking coil are formed on the same plane, it is not necessary to superpose the tracking coil and the focusing coil as in the conventional case, and variations in characteristics of each product due to superposition occur. Therefore, the quality can be made uniform.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the optical pickup device of the present invention will be described below with reference to Embodiment 1 shown in the accompanying drawings.

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

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. ), Two slits are formed so that the outer yoke 9 of the yoke 6 is formed by cutting and raising a portion between these slits, and the outer yoke 9 and the base substrate 2 are formed. A slit is formed in a U-shape facing the outer yoke 9 in a portion between the rear end edge and the inner yoke 10 of the yoke 6 by cutting and raising a portion surrounded by the slit. Has been done,
An appropriate space 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 the opposite pole is magnetized so as to be divided into two equal parts in the longitudinal direction.
It is attached to the surface of the inner yoke 10 that faces the outer yoke 9. As a result, the magnet 7—the inner yoke 10—the base substrate 2—the outer yoke 9—the gap between the magnet 7 and the outer yoke 9—the magnet 7 Circuit is formed,
A magnetic field 11 is generated between the magnet 7 and the outer yoke 9.

[0028]

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

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 into the slits 12a, 12a.
And is supported by the biaxial holder 12.

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 are displaced toward the center as they go forward. It has a rectangular shape, and a rectangular hole 14 that is long in the left-right direction is formed in a substantially central portion of the objective lens 3.
Is supported.

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 space between the 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
Is a support to which the tips of the parallel links 4, 4, ... Are joined.
Holding sectionFifteen, fifteenAnd the thick wall behind the rectangular hole 14
Department16Balances the weight of the lens holding member 5.
It is used as a balancer section for. Balancer section16
Is the center of gravity of the lens holding member 5 and the
Size so that the drive center of the printed circuit board matches
Is determined.

Numerals 17 and 17 are notches formed by notching so as to vertically penetrate the portions corresponding to the supported portions 15 and 15 of the rectangular hole 14.

The coil substrate 8 has a substantially rectangular shape and is formed such that its four corners are obliquely cut out, and further, the left and right side edges are slightly projected to the left and right to form the fitted portions 18, 18.
(See FIG. 8) By fitting the fitted portions 18, 18 into the cutout portions 17, 17 of the rectangular hole 14, the coil substrate 8 is positioned in the rectangular hole 14, and in this state, the fitted portion 18 is fitted. The upper and lower edges of the joining portions 18, 18 are positioned so as to slightly project upward or downward from the upper surface or the lower surface of the supported portions 15 , 15 .

The coil board 8 is formed by stacking four thin printed boards 8a, 8b, 8c and 8d on top of each other. Focusing coil elements 19, 19 ... Are provided on the thin printed boards 8a, 8b, 8c and 8d, respectively. .. 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 tracking coil element 20 is surrounded by four corners thereof. 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 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 and formed as through holes. 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, respectively.
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 15, 15 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 15 , 15 , 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 is provided with 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
And are opposed to the left side portion 7l of the magnet 7, and a portion 23 of the focusing coil 23 located on the upper right side.
Ru lower part 23 rud and lower right part 23
The upper part 23rdu of rd and the right part 24r of the tracking coil 24 are the left part 7 of the magnet 7.
It faces r (see FIG. 8).

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.

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 16 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.

[0050]

As is clear from the above description, the optical pickup device of the present invention is provided with a lens holder holding an objective lens, an elastic member supporting the lens holder, and a fixing member provided on the fixing portion side. A pair of flat plate-shaped magnets and a pair of flat plate-shaped yokes facing the magnets;
Together is attached to the lens holder, it is disposed between the magnet and the yoke, the printed circuit board thickness direction odor
Shape as a circuit pattern on the same plane so that they do not overlap.
Made is provided with a set of flat plate-shaped focusing coil and tracking coils, the corresponding central portion of the magnet
The tracking coil is placed at
Attach each side of the racking coil to each pole of the magnet.
Focusing coil is placed and the N pole of the magnet
On one side and one side of the tracking coil.
While matching the coil side of the focusing coil,
Connect the S pole of the net to the other coil of the tracking coil
It is characterized in that it corresponds to the coil side of the other focusing coil .

Therefore, according to the optical pickup device of the present invention, since the focusing coil and the tracking coil are formed on the same plane as the circuit pattern on the printed circuit board, the focusing coil and the tracking coil can be thinned and the magnet and The gap with the yoke, that is, the length of the magnetic field can be shortened, which can improve the driving efficiency, stabilize the operation of the biaxial actuator, and reduce the size. it can.

Further, since the focusing coil and the tracking coil are formed as a circuit pattern on the printed circuit board, there are few ineffective conductor portions and the conductor utilization efficiency is good, which makes it possible to reduce the weight of the movable portion of the biaxial actuator. The response characteristics of the biaxial actuator can be improved.

Further, since the focusing coil and the tracking coil are formed on the same plane, the driving action points do not deviate from each other, and the driving center and the center of gravity of the movable portion of the biaxial actuator can be matched. A stable operation of the movable part can be obtained.

Furthermore, since the focusing coil and the tracking coil are formed on the same plane, it is not necessary to superpose the tracking coil and the focusing coil as in the conventional case, and variations in characteristics of each product due to superposition occur. Therefore, the quality can be made uniform.

The specific shapes and structures of the respective parts shown in the above embodiments are merely examples of the implementation in implementing the optical pickup device of the present invention. The range should not be construed as limiting.

[Brief description of drawings]

FIG. 1 is an optical pickup device of the present invention together with FIGS.
FIG. 3 is a perspective view showing an example of implementation of the apparatus .

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.

FIG. 9 is a plan view showing an example of a biaxial actuator of a conventional optical pickup device.

10 is a cross-sectional view taken along line XX of FIG.

[Explanation of symbols]

3 Objective Lens 4 Parallel Link (Elastic Member) 5 Lens Holding Member (Lens Holder) 7 Magnet (Plate Magnet) 8 Coil Board (Printed Circuit Board) 9 Outer Yoke (Plate Yoke) 10 Inner Yoke (Plate Yoke) 19 Focusing Coil element (circuit pattern) 20 Tracking coil element (circuit pattern) 22 Feeding terminal 23 Focusing coil 23lud Lower part (coil side) 23ldu Upper part (coil side) 23rud Lower part (coil side) 23rdu Upper part (coil side) 24 Tracking coil

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B 7/09

Claims (2)

(57) [Claims] 1. A lens holder that holds an objective lens, an elastic member that supports the lens holder, a flat plate-shaped magnet provided on the fixed portion side, and a pair of flat plate-shaped yokes facing the magnet. , with mounted on the lens holder, it is disposed between the magnet and the yoke, the printed circuit board thickness
Circuit patterns on the same plane so that they do not overlap in the vertical direction.
And a pair of plate-shaped focusing coil and tracking coils which are formed as over emissions, the Tracking the position corresponding to the central portion of the magnet
And a tracking coil is arranged.
On both sides of the
A casing coil is arranged, and the N pole of the magnet is connected to one of the tracking coils.
On the edge of the focusing coil and one of the focusing coils.
And track the S pole of the magnet.
The other coil side of the coil and the other focusing coil
The optical pickup device is characterized by being adapted to the coil side of the cable. 2. As a circuit pattern of the printed circuit board
A set of flat-plate focusing coils and
On the same flat plate as the racking coil, feed from the above elastic member.
The optical pickup device according to claim 1, further comprising a power supply terminal for supplying electricity .