JP2003157560A - Objective lens driving device and disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize simply and at a low cost a correction of a radial skew of a disk which is generated synchronized with a side run-out of a turn table or a disk in the disk driving device. SOLUTION: Elastic supporting means which are arranged respectively inside and outside circumferences of the disk are provided for elastically supporting a movable part 20 including an objective lens so that the moving part is movable with respect to a fixed part 24. In a conformation in which a plurality of wires are used, for example, the extending length from a movable part to a fixed part of the wire which is arranged at outer circumference of the disk is longer than the wire which is arranged at inner circumference of the disk. Alternately, the lengths of both wires are identical and the driving center of the movable part is set at a position which is dislocated toward the outer circumference of a disk recording medium 10 with respect to the supporting center of the moving part 20. The skew due to the side run-out of the disk is corrected without changing the width, the wire diameter or the material of the elastic supporting means according to whether the elastic supporting means is arranged at the inner circumference side or the outer circumference side of the disk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for correcting a radial skew of a disc that is generated in synchronization with a surface deflection of a turntable or a disc in an objective lens driving device and a disc drive device using the same.

[0002]

2. Description of the Related Art Regarding the structure of an optical head (or optical pickup) for reading signal information from an optical disc-shaped recording medium and recording the information, an objective lens or an A suspension type in which a movable portion including a coil is movably supported with respect to a fixed portion including a magnet, and an elastic member such as a leaf spring or a wire is used as the supporting means to hold the movable portion. Are known.

By the way, if the attitude of the disk-shaped recording medium is always kept constant, the movable part is driven while the attitude of the objective lens is kept parallel to the recording surface of the disk-shaped recording medium. The control is easy because it is sufficient, but in reality, it is necessary to correct the skew (disk radial skew) that is generated in synchronization with the surface runout of the turntable or the disk-shaped recording medium. And
The method is to generate a radial skew in the lens in synchronization with the movement of the objective lens in the focus direction, that is, to change the posture of the movable part so as to cancel the skew generated in synchronization with the surface runout. There is known a method of performing drive control that follows surface deflection.

That is, a plurality of elastic members (leaf springs, wires, etc.) connecting the movable portion and the fixed portion for supporting the movable portion do not have the same characteristics, but are provided on the inner peripheral side of the disk. The shape and the like may be changed between the member positioned and the member positioned on the outer peripheral side of the disk. For example, when a leaf spring is used, its width is used, and when a wire is used, its diameter is asymmetrically designed so that the member positioned on the outer peripheral side of the disk is smaller, thereby achieving a focus. When driving in the direction, the outer peripheral portion of the disc with respect to the objective lens can be moved more greatly in the focusing direction. Therefore, the radial skew of the disk can be corrected by intentionally causing the inclination of the objective lens in synchronization with the above-mentioned surface wobbling.

[0005]

However, in the above-mentioned method, each elastic member used as a suspension (suspension means) for supporting the movable portion of the biaxial actuator needs to have a plurality of types having different shapes and the like. However, manufacturing management is troublesome and there is a problem in cost.

For example, a suspension type biaxial actuator using a leaf spring requires two kinds of members having different widths, and a suspension type biaxial actuator using a plurality of pairs of wires has a wire wire diameter At least two different types of wire rods are required, which may cause a problem of parts management (mixing of parts, etc.) and a cost increase.

Therefore, it is an object of the present invention to realize a correction for a disk skew that occurs in synchronization with a surface runout of a turntable or a disk, simply and at low cost.

[0008]

In order to solve the above-mentioned problems, the present invention elastically moves a movable part of an objective lens driving device with respect to a fixed part thereof in a state of being movable in a focus direction and a tracking direction. To connect and support
A pair or a plurality of pairs of elastic supporting means are provided respectively on the inner circumference side and the outer circumference side of the disc-shaped recording medium, and fixed from the movable part of the means arranged on the outer circumferential side of the disc-shaped recording medium. The length to the portion is made longer than the length from the movable portion related to the means arranged on the inner peripheral side of the disk-shaped recording medium to the fixed portion, or with respect to the support center of the movable portion by the elastic supporting means, The drive center of the movable portion is set at a position closer to the outer peripheral side of the disk-shaped recording medium.

In any case, the outer peripheral side portion of the movable portion can be driven in the focus direction with a relatively large amount of movement as compared with the inner peripheral side portion, and the objective lens that follows the surface wobbling of the disk can be driven. The attitude can be controlled, and the radial skew of the disk can be corrected.

Therefore, according to the present invention, there is no need to change the width, wire diameter, material, etc. depending on whether the elastic supporting means is arranged on the inner peripheral side or the outer peripheral side of the disk. There is no need to use multiple types of parts for the means.

[0011]

1 is a schematic diagram showing the basic structure of a disk drive device according to the present invention.

The disk drive device 1 is constructed by arranging required members and mechanisms inside an outer casing 2, of which only the main parts are shown in the drawing.

A chassis 3 is arranged in an outer casing 2 indicated by a chain double-dashed line, and a rotary table of a spindle motor attached to the chassis 3 has a turntable (or disk table).
4 is fixed.

A pair of parallel guide shafts 5 and 6 are attached to the chassis 3, and a feed shaft (lead screw) rotated by a motor (not shown) is supported.

The optical head 7 is provided with a moving base (or slide base) 8, and an objective lens driving device 9 is mounted on the moving base. That is, the apparatus has a configuration as a biaxial actuator for performing focus control and tracking control by driving the objective lens 9a. Both ends in the longitudinal direction of the moving base 8 are slidably supported by the guide shafts 5 and 6, and the moving base is linearly moved along the guide shaft by drive control of the feed shaft.

A disk-shaped recording medium (recording carrier) 10 indicated by a chain double-dashed line in the figure is inserted into the apparatus through the insertion opening 2a of the outer casing 2 and placed on the turntable 4 upon completion of disk chucking. To be done. And the moving base 8
The optical head 7 is moved in the radial direction of the disk-shaped recording medium 10 by the drive mechanism, the drive motor, and the feed shaft. As far as the present invention is concerned, the form of the disc-shaped recording medium does not matter, and therefore, an optical disc,
It goes without saying that the present invention can be widely applied to an apparatus using a magneto-optical disk, a phase change disk, or the like.

2 to 5 show an example of the structure of the optical head 7. FIG. 2 shows the assembled state, and FIG.
Shows an exploded perspective view. Further, FIG. 4 is an exploded perspective view showing the mechanism of the biaxial actuator, and FIG. 5 is an exploded perspective view showing a main part of the structure of the moving base. In this example, a suspension type configuration using four wires is shown, but the present invention is not limited to this and can be applied to various configuration forms using a leaf spring or the like.

As shown in FIGS. 2 and 3, a biaxial actuator 12 is mounted on a chassis 11 which constitutes the moving base 8 of the optical head 7, and a cover member 13 covers the chassis 11 from above. It has a main board (main flexible printed board) 14 and is connected to an external circuit (not shown). In FIG. 3, the cover member 13 and the upper yoke 15 are shown on the uppermost side, and the cover member 13 and the upper yoke 15 are shown on the lower side.
The shaft actuator 12, the chassis 11 below and the yokes 16, 16 attached to the chassis 11 and the magnet 1.
7 and 17, the main board 14 is shown therebelow. The upper yoke 15, the yoke 16 and the magnet 17 form a field portion (magnetic field generation portion) for a coil portion (coil assembly) described later.

As shown in FIG. 4, the objective lens 9a is received and fixed in a concave portion formed in the lens holder 18, and the coil portion 19 is provided in the lens holder.
A positioning hole for locating the coil is formed therein, and the coil portion 19 is received and fixed in this hole. Then, the objective lens 9a, the lens holder 18, and the coil unit 1
The movable portion 20 including the elastic support means 21, 21, ...
It is movably supported by the support portion 22 via (in this example, four wires).

The support portion 22 is disposed on a base member (biaxial base) 23, and the base member is the chassis 1.
It is adapted to be attached and fixed to the inner bottom surface of 1, and these members constitute a fixed portion 24 for the movable portion 20. In addition, each wire has a role of elastically connecting and supporting the movable portion 20 to the fixed portion 24, and in a state where the movable portion 20 is movable in the focus direction and the tracking direction with respect to the fixed portion 24. Supported. In the case of using the leaf spring instead of the wire, one end of the leaf spring is embedded in the lens holder 18 by insert molding, and the other end of the leaf spring is attached to the support portion 22 so that the movable portion is elastic to the fixed portion. Connected to and supported by.

A power supply board (flexible printed board) 25 is attached to a side surface of the support portion 22,
The supply of the drive current to the coil portion 19 is performed from the substrate via each wire (that is, the wire is a mechanical supporting means for the lens holder 18 and at the same time, is electrically connected to the coil portion 19). It is also a means.)

As shown in FIG. 5, a yoke base 26 is attached to the chassis 11 of the moving base 8 from below in the drawing, and a portion of the yoke base facing upward in the drawing and formed in a U-shape is a yoke. 16 and 16 are formed, and magnets 17 and 17 are attached to face each other inside. In addition, a projecting portion that is narrower than other portions is formed at a tip portion of each yoke 16, and an engaged portion having a shape corresponding to the portion is formed on the upper yoke 15. Therefore, the magnetic circuit is closed by engaging and coupling them. The magnets 17, 17 are arranged so as to face the coil portion 19 (focus coil and tracking coil), and constitute a part of the fixed portion 24 as a magnetic field portion together with the yokes 15, 16, 16.

One end 27 of the chassis 11 constitutes a main shaft portion for feed control, and a bearing 28 for the guide shaft 6,
28 is provided. Further, although engaging portions 29, 29 are formed at the end portion on the opposite side to the auxiliary shaft portion, the supporting mechanism and the feeding mechanism of the moving base 8 are known and their description and illustration are omitted. Omit it.

FIG. 6 schematically shows only a part of the biaxial actuator. A view seen from the optical axis direction of the objective lens is shown on the left side, and a view seen from a side orthogonal to the direction is shown on the right side. It is shown in.

Further, FIG. 7 schematically shows only the coil portion, and the arrows shown in the figure exemplify the direction of the current flowing through each coil.

The coil section 19 is composed of a focus coil (or focusing coil) 30 and a tracking coil 31, and is used for focus control of laser light emitted to the disk-shaped recording medium via the objective lens 9a. Drive current is focus coil 30
Drive current for tracking control relating to the laser light is supplied to the tracking coil 31. In this example, the pair of tracking coils 31, 3
1 is attached to the side surface of the focus coil 30, and the direction of the current flowing through each tracking coil is the same with respect to the plane of symmetry located in the middle of the two, as shown by the arrow in FIG. It is controlled so as to have a mirror image relationship with respect to the plane of symmetry.
Of course, the present invention is not limited to such a form, and a combination of two or more pairs of coils and various forms using a single coil are possible.

As shown in FIG. 6, the movable portion 20 including the coil portion 19 is elastically supported by the support portion 22 via elastic support means (suspension wires) 21, 21 ,. The objective lens 9a is arranged between the coil portion 19 and the support portion 22, and drive control of the movable portion 20 in the focus direction and the tracking direction is performed.

8 and 9 show the coil portion and the field portion, and are views for explaining the formation of the magnetic circuit. The right side of FIG. 8 shows a view from the upper yoke side, and the left side shows the coil portion 19, the yoke base 26, and the magnet 17 with the upper yoke 15 removed. Further, on the right side of FIG. 9, the view seen from the direction of arrow D in FIG. 8 is shown as a perspective view, and on the left side, the view seen from the direction of arrow R in FIG. 8 is shown as a perspective view. Incidentally, regarding each of the X and Y coordinate axes set in FIG.
The axis indicates the axis extending in the focus direction, and the X axis extending in the plane of the drawing orthogonal to the axis indicates the axis in the tracking direction.

As for the magnets 17 and 17 in an opposed state attached to the insides of the yokes 16 and 16, as shown by the polarity symbols “N” and “S” in FIG. Are arranged to face each other, and a part of the coil side of the focus coil 30 and the tracking coils 31, 31 are arranged between both magnets. Therefore, when the focus error signal due to the surface wobbling of the disk is detected, the drive current is supplied to the focus coil 30 so as to cancel the influence based on the signal, and as a result, the objective lens 9a is moved in the Y-axis direction. Driving force is generated (focus servo control). Further, when a tracking error signal due to eccentricity of the disk is detected, a driving current is supplied to the tracking coil 31 so as to cancel the influence based on the signal, and as a result, the objective lens 9a is moved in the X-axis direction. Drive force is generated (tracking servo control).

Next, the principle of the radial skew correction of the disk will be described. Before that, the schematic diagrams shown in FIGS. 10 and 11 will be used to define the directions relating to the focus control and tracking control and the definitions of the symbols relating to the skew. It demonstrates using.

FIG. 10 shows the definition relating to the biaxial actuator, and in the diagram viewed from the optical axis direction of the objective lens 9a, an arrow ("TRK") from left to right.
"+" Is attached. ) Indicates the tracking direction (the right side is defined as the forward direction).

On the right side of the drawing, a view seen from the tracking direction is shown, and the counterclockwise arrow ("Tan +") is shown.
Is attached. ) Indicates the tangential direction (the counterclockwise direction is defined as the forward direction).

Below the arrow labeled "TRK +", there is shown a schematic view of the movable portion 20 seen from a direction orthogonal to the plane including the optical axis direction and the tracking direction of the objective lens, and the upward arrow. (Indicated by adding “FCS +”) indicates the focus direction (upward is defined as the forward direction). Then, the counterclockwise arrow (“Rad +”
Is attached. ) Indicates the radial direction of the objective lens (that is, the direction around the vertical axis with respect to the paper surface of the drawing is shown, and the counterclockwise direction is defined as the positive direction).

FIG. 11 shows the definition of the coil portion, and the upward arrow (indicated by "FCS +") in the drawing indicates the focus direction (upward is defined as the forward direction). , The arrow pointing to the right (indicated by adding “TRK +”) indicates the tracking direction (the right side is defined as the forward direction).

FIG. 12 is a conceptual diagram for explaining the principle of the radial skew correction of the disk. The left side shows the situation (three states) when the correction is not performed, and the right side is the case when the correction is performed. The situation (3 states) is shown. still,
In these figures, the figure shown in the upper position shows the situation where the surface runout of the disc is in the upper direction of the figure, the figure in the middle shows the situation without the surface runout of the disc, and the figure shown in the lower position shows The figure shows the situation where the surface runout of the disk is in the downward direction of the figure.

In the case where no radial skew correction is performed (left figure), when there is no surface wobbling as shown in the middle figure, the attitude of the disk with respect to the center axis CA of the disk indicated by the dashed-dotted vertical line is the reference state. Since it is maintained in the (horizontal state), the objective lens has a positional relationship parallel to the disk surface when the movable portion 20 is in the neutral position in the focus direction.

On the other hand, in the figure shown above, when the surface deflection of the disk is in a direction (upward) away from the optical head 7, the movable part 20 moves in the positive focus direction (upward) with respect to the fixed part 24. Translate to FCS +). Therefore, the objective lens does not become parallel to the disk surface, and the relative radial direction (Ra
A skew of d +) will occur.

Further, in the drawing shown below, when the surface runout of the disk is in a direction (downward) approaching the optical head 7, the movable portion 20 moves in the negative focus direction (FCS-) with respect to the fixed portion 24. Translate to. Therefore, the objective lens 9a is not parallel to the disk surface,
The relative relationship between the two causes a skew in the radial negative direction (Rad-).

For example, when the disk radius is 32 mm and the surface runout is ± 0.2 mm, the radial skew (skew angle) is about ± 0.36 °. In addition to the inherent skew (so-called lens skew, which corresponds to the posture change of the movable portion in the radial direction) in the two-axis actuator, a radial skew synchronized with the surface runout of the turntable and the disk is added. The lens skew is usually designed to be minimal.

With radial skew correction (right figure), when there is no surface wobbling of the disk (middle figure), the attitude of the disk is kept in the reference state (horizontal state) with respect to the center axis CA of the disk. Is dripping Therefore, when the movable portion 20 is at the neutral position in the focus direction, the objective lens has a positional relationship parallel to the disk surface.

On the other hand, in the drawing shown above, when the surface deflection of the disk is in a direction (upward) away from the optical head 7, the movable part 20 moves in the positive focus direction (the upward direction) with respect to the fixed part 24. FCS +), but at that time, the movable portion 20 is moved to a larger extent in the outer peripheral portion than in the inner peripheral portion of the disk.
Clockwise direction (that is, "Rad +" as indicated by S1)
And the opposite direction). Therefore, in the relative relationship of the objective lens with respect to the disk surface, both are in a parallel positional relationship and the radial skew is corrected.

Further, in the drawing shown below, when the surface deflection of the disk is in a direction (downward) approaching the optical head 7, the movable part 20 moves in the negative focus direction (FCS-) with respect to the fixed part 24. However, in this case, the outer peripheral portion of the disk is moved more than the inner peripheral portion of the disk, and as a result, the movable portion moves in the counterclockwise direction (that is, as indicated by the dashed arrow LS2). , Opposite to "Rad-")
It becomes a leaning posture. Therefore, in the relative relationship of the objective lens with respect to the disk surface, both are in a parallel positional relationship and the radial skew is corrected.

As described above, with respect to the radial skew generated in synchronization with the surface runout of the turntable or the disc,
In order to perform control that follows the surface wobbling of the disk, if the objective lens (including the movable part) moves in the focus direction, move the outer peripheral part with a larger movement amount than the inner peripheral part. , The movable part can be tilted so that the movable part is parallel to the disk's radial skew so that the radial skew can be corrected (in other words, the lens skew can be minimized). It is difficult to make the posture of the objective lens follow the surface deviation of the disk when the radial skew of the disk occurs with the design that suppresses to.

When the movable portion 20 is moved in the focus direction, in order to move the portion of the movable portion on the outer peripheral side of the disc more than the portion on the inner peripheral side of the disc, the inner portion of the elastic support means 21 is The elastic coefficient of the one located on the peripheral side may be designed to be larger than the elastic coefficient of the one located on the outer peripheral side. For example, in the case of using four wires, the spring constants of the two wires on the inner circumference side should be made larger than the spring constants of the two wires on the outer circumference side (or, the same thing, That is, the spring constants of the two springs should be smaller than the spring constants of the two springs on the inner peripheral side. For that purpose, there is a method of changing the material of the wire material and the wire diameter of the wire. However, this causes the problems described above, and therefore the present invention takes the following forms.

(I) A form in which the length between the movable part and the fixed part is changed between the inner peripheral side and the outer peripheral side of the elastic supporting means (II) On the other hand, the drive center of the movable part is located at a position biased toward the outer peripheral side.

First, regarding the form (I), without changing the material, diameter, width, etc. of the elastic supporting means, of the means, the length of the means arranged on the inner peripheral side of the disk-shaped recording medium and the disk The length of the means arranged on the outer peripheral side of the flat recording medium is designed to be different. That is, the length from the movable part of the elastic supporting means arranged on the outer peripheral side of the disk-shaped recording medium to the fixed part is fixed from the movable part of the elastic supporting means arranged on the inner peripheral side of the disk-shaped recording medium. It is to be longer than the length to the part (with regard to the length of the wire, the leaf spring, etc. between the movable part and the fixed part, the one on the outer circumference side is made longer than the one on the inner circumference side). Accordingly, even with the same material, the portion of the movable portion supported by the longer elastic support member located on the outer peripheral side can be moved more in the focus direction than the portion on the inner peripheral side.

13 to 15 are explanatory views of such a structure. FIG. 13 is a schematic view of the biaxial actuator viewed from the optical axis direction of the objective lens, and FIG. 14 includes the focus direction and the tracking direction. The figure which shows the wire arrangement | positioning seen from the direction orthogonal to a surface, and FIG. 15 is explanatory drawing which shows the movement of a movable part schematically.

In FIG. 13, the right side shows the inner peripheral side of the disk, and of the four wires (the front two are shown in the figure) of the same material and the same diameter, the inner peripheral side is shown. The movable portion 20 and the fixed portion 2 of the pair of wires located at
The length spanning 4 and 4 is “Li”. For the pair of wires located on the outer peripheral side, the length across the movable portion 20 and the fixed portion 24 is “Lo”, and as shown in the figure, “Lo> Li” (not the total wire length). Note that.).

Even if "Lo>Li", since it is necessary to prevent the posture of the movable portion from tilting in a plane parallel to the paper surface of the figure, the connecting portion of the wire pair to the movable portion is , It is necessary to adjust the height and position, so the fixed part 2
By projecting a portion 24a of 4 toward the movable portion 20, the sum of the length of the portion and Li is made equal to Lo.

As shown in FIG. 14, the four wires are respectively positioned corresponding to the vertices of the quadrangle shown by the dotted line,
The inner wire pair 32, 32 shown on the right side of the figure and the outer wire pair 33, 33 shown on the left side have the same wire diameter (as described above, the latter is longer). The black dots in the figure indicate the drive points P related to the movable part, and the upward arrows indicate the positive focus direction (FCS +).

FIG. 15 schematically shows the movable portion in three states, and the middle portion shows the neutral portion of the movable portion 20. If the movable portion 20 is moved in the positive focus direction (FCS +) with respect to the driving point P indicated by a black dot from this state, the state shown in the above figure is obtained, and the portion on the outer peripheral side moves more than the inner peripheral side and the movable portion 20 moves. It becomes tilted in the radial negative direction. In addition, from the neutral state shown in the center, the driving point P
When the movable portion 20 is moved in the negative focus direction (FCS-) as shown in the figure below, the movable portion 20 also moves largely in the outer peripheral side than in the inner peripheral side, and the movable portion is tilted in the radial positive direction. Become.

Next, the form (II) will be described.
In this case, the drive point is not set at the support center of the movable portion by the elastic support means, but is set at a position displaced from the support center in the tracking direction. In other words, the drive center of the movable part is defined so as to come to a position closer to the outer peripheral side of the disk-shaped recording medium with respect to the support center of the movable part, and the disk outer periphery than the part of the movable part on the inner side of the disk The radial skew of the disc can be corrected by moving the side portion with a larger movement amount in the focus direction.

FIG. 16 is a view showing the wire arrangement as seen from a direction orthogonal to a plane including the focus direction and the tracking direction, and FIG. 17 is an explanatory view schematically showing the movement of the movable part.

In the present embodiment, the lengths of the wires extending over the movable portion and the fixed portion are equal, but as shown in FIG. 16, the four wires 34, 34, ... Correspond to the vertices of a quadrangle indicated by the dotted line. Drive points P indicated by black dots are set at positions deviated from the center of the quadrangle (support center or suspension center indicated by “+” mark) to the outer peripheral side (left side in the drawing). (That is, an offset is given to the driving point P). Therefore, since the rotational moment corresponding to the driving force in the focus direction acts on the outer peripheral side portion of the movable portion, that portion is moved more than the inner peripheral side.

FIG. 17 shows the movable part in three states, and the middle part shows the neutral state of the movable part 20. If the movable portion 20 is moved in the positive focus direction (FCS +) with respect to the driving point P indicated by a black dot from this state, the state shown in the above figure is obtained, and the portion on the outer peripheral side moves more than the inner peripheral side and the movable portion 20 moves. It becomes tilted in the radial negative direction. When the driving point is moved in the negative focus direction (FCS-) from the neutral state shown in the middle, the movable unit 2
0 becomes the state shown in the figure below, and the portion on the outer peripheral side also moves largely as compared to the inner peripheral side, so that the movable portion 20 is tilted in the radial positive direction. In this way, the drive point is set at a position deviated from the center of the suspension to the outer peripheral side, and the movable portion 2
By driving 0, it is possible to provide the same function as the above-mentioned form (I) in which the wire span length is set differently in the inner and outer circumferences of the disc, and a radial skew of the objective lens is generated (that is, movement in the radial direction). It is possible to follow the surface wobbling of the disk-shaped recording medium by changing the posture of the section).

In order to drive the movable part by displacing the drive point P to the outer peripheral side of the center of the suspension, the magnet or the like forming the field part is displaced to the outer peripheral side of the disk with respect to the center of the focus coil. It can be easily realized by mounting it in the specified position. That is, in the examples shown in FIGS. 8 and 9, the two magnets 17, 17 and the yoke base 26 that supports these magnets constitute a field magnet portion, and the positional relationship between the focus coil and the tracking coil is shown. Is set to a neutral position before driving, but the magnet 17 and the yoke base 26 may be displaced from this position to the outer peripheral side of the disk and attached to the chassis 11. That is, in FIG. 8, the focus coil 30
The positional relationship between the magnet 17 and the yoke 16 is defined so that the surface including the central axis of the magnet 17 and the surface including the central axis of each magnet 17 coincide with each other. Side (X in FIG. 9
This can be dealt with by adopting a structure in which the yoke base 26 is mounted with an offset in the negative direction of the shaft) or the mounting position of the yoke base 26 on the chassis 11 can be adjusted with respect to the coil portion 19. Therefore, the design of the support structure for the movable part of the biaxial actuator is not significantly changed, and the setting and adjustment of the magnetic field position with respect to the coil part is sufficient, so that there is almost no cost.

With the above arrangement, however, the following advantages can be obtained.

With respect to a suspension using a wire, a leaf spring, etc., the outer circumference side and the inner circumference side of the disk are made to have different lengths, or a focus is set as a driving point at a position offset from the center of the suspension to the outer circumference side of the disk. By controlling the objective lens and the movable part, the part on the outer peripheral side of the disc is moved more than the inner peripheral side in the focusing direction, and the radial skew of the disc that occurs in synchronization with the surface runout of the turntable or disc is controlled. Can be corrected.

The total radial skew of the disc and the objective lens can be minimized, and for that reason, new parts may be added, the cost may be increased, or the mechanism may be drastically modified. Absent.

· For surface wobbling and skew of the disc,
It is possible to realize an optical head having high reproduction or recording performance, which makes it possible to perform high accuracy and highly reliable control as a reproduction or recording device.

[0061]

As is apparent from the above description, according to the inventions according to claims 1 and 3, the elastic supporting means is arranged on the inner peripheral side or the outer peripheral side of the disk. Depending on whether or not the turntable and the fixed portion are arranged such that the length arranged on the outer peripheral side of the disc is longer than the length arranged on the inner peripheral side of the disc, It is possible to correct the radial skew of the disk that occurs in synchronization with the surface wobbling of the disk. Further, since it is not necessary to change the width, the wire diameter, and the material of the elastic supporting means, it is not necessary to use a plurality of types of parts for the means, the cost is low, and the burden on parts management is small. Further, in the disk drive device, it contributes to the improvement of the accuracy of the signal recording and the signal reproducing process, so that the quality and performance of the product can be improved.

According to the inventions of claims 2 and 4,
Only by setting the position of the drive center (drive point) with respect to the support center of the movable part, the correction related to the radial skew of the disk can be performed.
It can be realized by a simple method with almost no cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a disk drive device.

FIG. 2 shows an example of the configuration of an optical head together with FIGS. 3 to 5, and is a perspective view showing an assembled state.

FIG. 3 is an exploded perspective view.

FIG. 4 is an exploded perspective view showing a mechanism of a biaxial actuator.

FIG. 5 is an exploded perspective view showing a main part of a moving base.

FIG. 6 is a diagram schematically showing a biaxial actuator.

FIG. 7 is a diagram schematically showing a coil unit.

8 shows a coil portion and a field portion together with FIG. 9, and this figure is a plan view.

FIG. 9 is a view seen from the side.

FIG. 10 is a view for explaining the radial skew correction of the disk with FIGS. 11 and 12, and is a schematic view showing the definition of the direction and the reference sign.

FIG. 11 is a schematic diagram showing definitions of directions and the like regarding a coil portion.

FIG. 12 is a conceptual diagram for explaining a principle relating to radial skew correction of a disc.

FIG. 13 is a view for explaining an example of a configuration in which the wire running length is different between the disk inner circumference side and the disk outer circumference side together with FIGS. 14 and 15, and this figure shows the optical axis. It is the schematic of the biaxial actuator seen from the direction.

FIG. 14 is an explanatory diagram showing a wire arrangement.

FIG. 15 is a schematic explanatory diagram of movement of a movable portion.

16 is a diagram for explaining the position setting in which the driving point is displaced from the support center together with FIG. 17, and this diagram is an explanatory diagram showing a wire arrangement. FIG.

FIG. 17 is a schematic explanatory diagram of movement of a movable portion.

[Explanation of symbols]

1 ... Disk drive device, 4 ... Turntable, 7 ...
Optical head, 9a ... Objective lens, 9 ... Objective lens driving device, 10 ... Disk recording medium, 17 ... Magnet, 2
0 ... Movable part, 21 ... Elastic support means, 24 ... Fixed part, 30
… Focus coil, 31… Tracking coil

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masanori Ogata             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F-term (reference) 5D118 AA13 BA01 EA02 ED08 FA27                       FB03

Claims (4)

[Claims] 1. An objective lens, a focus coil to which a drive current is supplied for focus control of a laser beam applied to a disk-shaped recording medium through the objective lens, and a tracking coil for the laser beam. A movable part having a tracking coil to which an electric current is supplied, a fixed part having a magnet arranged for the focus coil and the tracking coil, and the movable part in the focusing direction and the tracking direction with respect to the fixed part. The movable portion is elastically connected to and supported by the fixed portion in a movable state, and is in a direction substantially orthogonal to the tracking direction and on the inner and outer peripheral sides of the disc-shaped recording medium. A pair of elastic support means or a plurality of pairs of elastic support means, each of which is arranged in a disk shape. The length from the movable portion related to the means arranged on the outer peripheral side of the recording medium to the fixed portion is set to An objective lens driving device characterized in that by making the length longer than the fixed portion, the posture of the movable portion is changed according to the movement of the movable portion in the focus direction so as to follow the surface wobbling of the disk-shaped recording medium. 2. An objective lens, a focus coil to which a drive current is supplied for focus control of laser light emitted to a disk-shaped recording medium through the objective lens, and a drive for tracking control of the laser light. A movable part having a tracking coil to which an electric current is supplied, a fixed part having a magnet arranged for the focus coil and the tracking coil, and the movable part in the focusing direction and the tracking direction with respect to the fixed part. The movable portion is elastically connected to and supported by the fixed portion in a movable state, and is in a direction substantially orthogonal to the tracking direction and on the inner and outer peripheral sides of the disc-shaped recording medium. A pair or a plurality of pairs of elastic supporting means arranged respectively, and supporting the movable part by the elastic supporting means. By setting the drive center of the movable part at a position closer to the outer peripheral side of the disc-shaped recording medium with respect to the center, the posture of the movable part is changed to follow the surface wobbling of the disc-shaped recording medium. An objective lens driving device characterized by: 3. A disk drive device comprising a turntable for mounting and rotating a disk-shaped recording medium, and an optical head for reproducing or recording information on the disk-shaped recording medium. The lens driving device supplies a focus coil with a drive current for focus control of the laser light emitted to the disk-shaped recording medium through the objective lens, and a drive current for tracking control of the laser light. A movable part having a tracking coil, a fixed part having a magnet arranged for the focus coil and the tracking coil, and a state in which the movable part is movable in the focus direction and the tracking direction with respect to the fixed part. When the movable part is elastically connected to and supported by the fixed part, In addition, a pair of or a plurality of pairs of elastic supporting means arranged in a direction substantially orthogonal to the tracking direction and arranged on the inner peripheral side and the outer peripheral side of the disk-shaped recording medium are provided. Of the means, the length from the movable part to the fixed part relating to the means arranged on the outer peripheral side of the disk-shaped recording medium is set to the means arranged on the inner peripheral side of the disk-shaped recording medium of the elastic supporting means. By making the length from the movable portion to the fixed portion longer, the posture of the movable portion is changed according to the movement of the movable portion in the focus direction, and the surface wobbling of the disk-shaped recording medium is followed. Disk drive device. 4. A disk drive device comprising a turntable for mounting and rotating a disk-shaped recording medium, and an optical head for reproducing or recording information on the disk-shaped recording medium, wherein an objective constituting the optical head is provided. The lens driving device supplies a focus coil with a drive current for focus control of the laser light emitted to the disk-shaped recording medium through the objective lens, and a drive current for tracking control of the laser light. A movable part having a tracking coil, a fixed part having a magnet arranged for the focus coil and the tracking coil, and a state in which the movable part is movable in the focus direction and the tracking direction with respect to the fixed part. When the movable part is elastically connected to and supported by the fixed part, In addition, a pair of or a plurality of pairs of elastic supporting means arranged in a direction substantially orthogonal to the tracking direction and arranged on the inner peripheral side and the outer peripheral side of the disk-shaped recording medium are provided. By setting the drive center of the movable portion at a position closer to the outer peripheral side of the disc-shaped recording medium with respect to the support center of the movable portion by the means, the posture of the movable portion is changed and A disk drive device characterized by following surface wobbling.