JP2003030873A - Objective lens driving device, optical pickup device and optical disk unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce tilt (DC tilt) generated by focusing and tracing operations, in a 4 WS type objective lens driving device. SOLUTION: A pair of bar-like elastic supporting members 3 which is respectively disposed on each side in the axial direction of an objective lens 1 nearly in a truncated chevron shape, thereby adjusting rigidity of a plurality of elastic fixing parts 13 in an elastic substrate 12 on which the end of each bar-like elastic supporting member is fixed. Consequently, the position of the supporting center of the moving part can be adjusted, without changing the position of the driving force center in the objective lens driving device, in the manner that the position of this driving force center coincides with that of the supporting center of the moving part. Thus, DC tilt can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device for an optical disk drive or a magneto-optical disk drive,
The present invention relates to an optical pickup device and an optical disc device.

[0002]

2. Description of the Related Art There are several types of objective lens driving devices of this type, and a 4-wire spring system (4WS system) is a system that is low in cost and advantageous in reducing the weight of moving parts.

A conventional example of this 4WS type objective lens driving device (an example disclosed in Japanese Patent Laid-Open No. 8-22626 ...
14) is shown in FIG.

In this objective lens driving device, an objective lens holding member 102 holding the objective lens 101 is elastically supported by four wire springs 103. A focusing coil 104 wound in a cylindrical shape is attached to the objective lens holding member 102, and a tracking coil 105 wound in a flat shape is attached to one side surface of the focusing coil 104 in a cylindrical shape. Then, the objective lens holding member 102, the objective lens 101, the focusing coil 104, and the tracking coil 105.
The movable portion 106 is formed by the above.

The movable portion 106 is supported by a base 107 via a fixing member described later, and a yoke 108 is fixed on the base 107, and a pair of driving magnets 109 are opposed to the yoke 108. These driving magnets 109 are arranged with a gap so that the magnetic flux penetrates the driving portions of the focusing coil 104 and the tracking coil 105.

In such a structure, by passing a current through the focusing coil 104 and the tracking coil 105, the objective lens 101 can be moved in the focusing direction (Y direction) and the tracking direction (X direction). In addition, 110 is a fixing member which is fixed on the base 107 and supports one end side of the four wire springs 103, and 111 is a holding member which holds both ends of the wire spring 103 by a hinge structure which is movable in the axial direction thereof. is there.

[0007]

However, as shown in FIG. 14, a drive motor including a magnetic circuit formed by facing the drive magnet 109 and a coil (focusing coil 104, tracking coil 105) is provided. In the case of the objective lens driving device, the objective lens 101 (movable part 1
06) is a major problem when the objective lens 101 is tilted when it is moved in the focusing direction and the tracking direction. This tilt will be called a DC tilt.

The principle of generation of this DC tilt will be described with reference to FIGS. FIG. 15 is a schematic plan view showing an extracted portion of the drive motor, and FIG. 16 is a schematic front view thereof. FIG. 15A shows the focusing coil 10.
4 and the drive magnet 109 are attached, the parts precision is ideal, and the drive force center F and the four wire springs 10 are shown.
The movable part support center S of the movable part 106 supported by 3 coincides. In this state, no moment is generated even if the movable portion 106 (see FIG. 14) is moved in the focusing direction.

However, the drive force center F and the movable part support center S may not coincide with each other, as shown in FIG. 15B, depending on the precision of parts of the focusing coil 104 and the drive magnet 109 and the precision of assembly. Now, when the movable portion 106 is moved in the focusing direction when the driving force center F and the movable portion support center S deviate from each other as shown in FIG. A moment as shown in FIG. 16 is generated, and the movable portion (objective lens 101) 106 is tilted.

In recent years, in an optical disk, an objective lens having a high numerical aperture NA has come to be used in order to reduce the light spot diameter due to the necessity of high density recording. Since an objective lens having a high NA is likely to have coma aberration due to its tilt, the demand for the tilt of the objective lens accompanying the focusing operation and the tracking operation has become strict.

In order to deal with such a problem, for example,
Japanese Patent Laid-Open No. 11-134679 proposes an objective lens driving device in which a stem (fixing member) is movable and adjustable with respect to a magnetic circuit (second conventional example). An example of the configuration is shown in FIG. 17 (note that the portions corresponding to those in FIG. 14 are denoted by the same reference numerals ... FIGS. 18 to 20.
But the same).

The base 107 has yokes 108a and 108b.
Are integrally formed, and driving magnets 109a and 109b are fixed to the yokes 108a and 108b, respectively.
Further, the fixing member 1 is fixed to the base 107 by screws 112.
10 is fixed. The fixing member 110 has an insertion hole (not shown) through which the screw 112 is inserted, and the insertion hole is formed to have a diameter larger than that of the screw 112. A pair of protrusions 110a and 110b are formed on the mounting surface of the fixing member 110 to the base 107.
7, elongated holes 107a and 107b are formed which are fitted in the protrusions 110a and 110b and are long in the direction (radial direction) in which the fixing member 110 is moved. Also, the base 1
A pressing screw 113 for pressing the fixing member 110 in the moving direction is attached to 07.

According to this objective lens driving device, the movable part 106 can be moved and adjusted in the radial direction with respect to the magnetic circuit by rotating the pressing screw 113 and pressing the fixed member 110. By eliminating the deviation between the center F of the driving force and the center S of the support of the movable portion, which is generated in the example, it is possible to prevent the generation of a moment and reduce the DC tilt.

However, in the case of the second conventional example,
Since the objective lens 101 also moves in the radial direction with the movement adjustment of the fixed member 110, an optical axis shift (shift between the optical axis of the laser and the optical axis of the objective lens 101) occurs. Further, there is a problem that the radial gap between the magnetic circuit and the movable portion 106 must be increased by the adjustment amount.

In contrast to the case of Japanese Patent Laid-Open No. 11-134679, there is also a proposal that the drive magnet can be moved and adjusted with respect to the stem (fixing member) (third conventional example). An example of the configuration is shown in FIG. That is, in this objective lens driving device, the fixing member 110 is fixed and the driving magnet 1 is
The problem of optical axis shift in the second conventional example is solved by moving and adjusting 09a and 109b in the radial direction. In the figure, 114 is a substrate, 115 is an optical disk, 11
6 is a rising prism and 117 is solder for fixing the wire spring 103.

However, the third conventional example is also similar to the second conventional example in that the radial gap between the magnetic circuit and the movable portion 106 must be increased by the adjustment amount. In addition, a jig is inserted into a slight gap between the magnetic circuit and the movable portion 106 to drive the drive magnet 109.
Since a and 109b are moved and adjusted, there is a risk of damaging the wire spring 103 that supports the movable portion 106.

Further, the second conventional example and the third conventional example have another problem. In the 4WS type objective lens driving device, resonance (roll resonance) in which the movable portion rotates in the rotation direction about the longitudinal direction of the wire spring 103.
Occurs, and the roll resonance causes the objective lens to largely tilt in the radial direction. This tilt will be called an AC tilt. This AC tilt occurs due to the deviation between the driving force center F of the objective lens driving device and the inertia center (position of the center of gravity) of the movable portion 106.

The deviation between the center F of the driving force and the center S of the support of the movable portion, which is generated in the 4WS type objective lens driving device, is mainly due to an error in fixing the wire spring 103.
The driving force center F and the center of inertia of the movable portion 106 are not significantly deviated.

However, as described in the second and third conventional examples, the coil (focusing coil 104) is used.
When the positional relationship between the magnetic force and the magnetic circuit is adjusted to move the position of the driving force center F, the driving force center F and the movable portion 10 are moved.
A deviation from the center of inertia of 6 causes an AC tilt to easily occur.

Further, as a 4WS type objective lens driving device in which the DC tilt is reduced, Japanese Patent Laid-Open No.
As described in Japanese Patent Application Laid-Open No. 0-207757, there is a proposal using a driving magnet magnetized in four divisions (fourth conventional example), and the configuration thereof is shown in FIGS. 19 and 20. FIG. 19 is an exploded perspective view showing a drive motor, FIG. 20 is an explanatory view thereof, (a) is a horizontal sectional view of the coil as seen from the focusing direction, (b) is a characteristic view showing a magnetic field distribution in the tracking direction, (C) is a front view showing an arrangement relationship between a coil and a driving magnet, (d) is a characteristic view showing a magnetic field distribution in the focusing direction, and (e) is a longitudinal side view of the coil as seen from the tracking direction.

In this objective lens driving device, the yoke 10
The drive magnets 118a and 118b, which are divided into four in a cross shape with respect to 8a and 108b, are fixed. The coils (focusing coil 119 and tracking coil 120) arranged at positions facing the driving magnets 118a and 118b and fixed to the objective lens holding member are both formed in a planar shape.

The drive magnets 118a and 118b are magnetized in four divisions with the cross-shaped magnetizing boundary lines a and b as boundaries (quadrupole magnetizing), and the magnetizing direction is the focusing direction (Y axis). Direction) and a tracking direction (X-axis direction), which is perpendicular to the plane including the biaxial direction (Z-axis direction) and opposite to the adjacent region.

The focusing coil 119 is formed of a planar coil, and two objective coil holding members are provided on both sides of the magnetization boundary line a in the focusing direction, and the objective lens holding member is located at a position where the magnetization boundary line b in the tracking direction is crossed. (Not shown). On the other hand, the tracking coil 12
Two 0s are provided on both sides of the magnetization boundary line b in the tracking direction, and are respectively held by the objective lens holding member across the magnetization boundary line a in the focusing direction.

Thus, the four-pole magnetized drive magnet 118 is used.
By configuring the driving motor using a and 118b, the movable portion including the objective lens can be driven in the biaxial directions of the focusing direction and the tracking direction.

According to this structure, the center of the driving force in the focusing direction (or the tracking direction) during the tracking operation (or the focusing operation) and the center of the movable portion supported by the four wire springs are radial. Since the deviation in the direction (or the focus direction) is not as large as that in the first conventional example, it is possible to reduce the tilt (DC tilt) of the objective lens when the movable portion moves. Because the driving magnet is larger than the driving force generating portion of the coil, the driving force center in the focusing direction (or the tracking direction) is substantially aligned with the movable portion during the tracking operation (or the focusing operation). Because of the movement, the positional relationship with the movable portion support center of the four wire springs that move together with the movable portion can be maintained, and the generation of the moment can be reduced.

However, also in the objective lens driving device of the fourth conventional example, when the movable part is assembled with four wire springs, the center of the driving force and the center of support of the movable part depend on the accuracy of the parts and the accuracy of assembly. Is likely to cause a shift, and the DC tilt due to this remains.

Moreover, according to the fourth conventional example, since the influence of the positional deviation between the magnetic circuit and the coil (focusing coil 119 or tracking coil 120) is small, the center F of the driving force and the center of support of the movable part are assembled. S
Even if the deviation occurs, it is difficult to reduce the DC tilt by adjusting the positional relationship between the magnetic circuit and the coil as in the second and third conventional examples.

It is an object of the present invention to adjust a rigidity of a member for supporting a rod-shaped elastic supporting member in a 4WS type objective lens driving device by adjusting rigidity of a member supporting the rod-shaped elastic supporting member without increasing component accuracy or assembly accuracy. Absorb assembly error,
This is to reduce the tilt (DC tilt) generated by the focusing operation and the tracking operation.

Another object of the present invention is to reduce DC tilt without causing AC tilt in a 4WS type objective lens driving device.

[0030]

The invention according to claim 1 is
A movable part that includes an objective lens that forms a light spot, an objective lens holding member that holds the objective lens, and a driving coil, a fixed member that is fixed to the base, and one end side that is fixed to the movable part. A plurality of rod-shaped elastic support members that elastically support the movable portion with respect to the base by fixing the end side to the fixed member, and the drive coil attached to a yoke provided on the base. In the objective lens driving device including a driving magnet that forms a magnetic circuit together with the yoke by being closely opposed to each other, the rod-shaped elastic supports arranged in pairs on both sides in the optical axis direction of the objective lens. The member is arranged in a substantially V shape in which the width fixed to the movable portion is narrow and the width fixed to the fixed member is wide, and the member is arranged on the back side of the surface of the fixed member facing the movable portion. An end portion of the rod-shaped elastic support member on the side of the fixing member is fixed, and an elastic substrate having elasticity in a substantially axial direction of the rod-shaped elastic support member is fixed, and an end portion of the rod-shaped elastic support member is attached to the elastic substrate. A plurality of elastic fixing portions, which are fixed portions, are formed, and the rigidity of the elastic fixing portions is adjusted.

Therefore, by adjusting the rigidity of the plurality of elastic fixing portions to which the ends of the rod-shaped elastic support members are fixed, the center of the driving force of the objective lens driving device is not changed. Is adjusted so that the movable part support center coincides with the movable part support center. As a result, the DC tilt can be reduced, and since the center of the driving force of the objective lens driving device does not move during the adjustment for reducing the DC tilt, the center of the driving force and the center of inertia of the movable portion are adjusted before and after this adjustment. Can be maintained as originally designed, and it is possible to prevent the occurrence of AC tilt caused by the displacement of the center of the driving force and the center of inertia of the movable portion.

According to a second aspect of the present invention, in the objective lens driving device according to the first aspect, the plurality of elastic fixing portions to which the ends of the plurality of rod-shaped elastic supporting members are fixed are formed independently of each other. Has been done.

Therefore, the rigidity of each elastic fixing portion can be easily adjusted.

"A plurality of elastic fixing portions are formed independently of each other" means, for example, that the elastic substrate is formed in an H shape and each of the four protruding portions is used as an elastic fixing portion. To be achieved.

According to a third aspect of the present invention, in the objective lens driving device according to the first or second aspect, the rigidity of the elastic fixing portion is adjusted by adjusting the length dimension of the elastic fixing portion. There is.

Therefore, the rigidity of each elastic fixing portion can be adjusted by a simple adjustment. By reducing the length of the elastic fixing portion, the rigidity of the elastic fixing portion increases.

According to a fourth aspect of the present invention, in the objective lens driving device according to the third aspect, a part of the elastic fixing portion is adhered to the fixing member with an adhesive so that the elastic fixing portion has a length dimension. Has been adjusted.

Therefore, the length of each elastic fixing portion can be easily adjusted, and the fine adjustment can be easily performed.

It should be noted that, by increasing the area of adhesion of the adhesive to the fixing member in the vicinity of a certain elastic fixing portion, the elastic fixing portion is adjusted so that the length dimension becomes short, and the rigidity of the elastic fixing portion is adjusted. Becomes higher.

According to a fifth aspect of the present invention, in the objective lens driving device according to the third aspect, a length dimension of the elastic fixing portion is obtained by inserting and fixing a spacer between the elastic fixing portion and the fixing member. Has been adjusted.

Therefore, the length of each elastic fixing portion can be adjusted by adjusting the insertion fixing position of the spacer.

Since the spacer is inserted and fixed between the elastic substrate and the fixing member in the vicinity of a certain elastic fixing portion, the elastic fixing portion is adjusted so that its length dimension is shortened. The rigidity of the elastic fixing portion is increased.

According to a sixth aspect of the present invention, in the objective lens driving apparatus according to the fifth aspect, the spacer fixedly inserted between the elastic fixing portion and the fixing member is used when a tilt amount of the movable portion is inspected. The size is different according to the inspection result.

Therefore, it is not necessary to adjust the insertion position when inserting and fixing each spacer, spacers of different sizes can be inserted with reference to the same insertion reference point, and the rigidity by adjusting the length of each elastic fixing portion can be improved. The accuracy of adjustment can be improved.

According to a seventh aspect of the present invention, in the objective lens driving device according to the first or second aspect, the rigidity of the elastic fixing portion is adjusted by applying an adhesive on the surface of the elastic fixing portion. ing.

Therefore, the rigidity of the elastic fixing portion is adjusted by changing the thickness of the elastic fixing portion due to the applied adhesive, and the rigidity of the elastic fixing portion can be easily adjusted.

According to an eighth aspect of the invention, in the objective lens driving device according to the first or second aspect, the rigidity of the elastic fixing portion is adjusted by using a viscoelastic material between the elastic fixing portion and the fixing member. It is done by injecting.

Therefore, the rigidity of the elastic fixing portion can be easily adjusted.

The ninth aspect of the present invention provides the first to eighth aspects.
In the objective lens driving device according to any one of items 1 to 3, the driving magnet is divided into four areas in a cross shape and is perpendicular to a surface including a biaxial direction of a focusing direction and a tracking direction, and The drive coil is magnetized in the opposite direction to the adjacent region, and the drive coil is located on both sides of the magnetization direction boundary line in the focusing direction in the vicinity of the surface of the drive magnet and straddles the magnetization boundary line in the tracking direction. And two tracking coils provided on both sides of the magnetization boundary line in the tracking direction in the vicinity of the surface of the drive magnet and straddling the magnetization boundary line in the focusing direction. It consists of a coil.

Therefore, even in the case of an objective lens driving device using a quadrupole magnetized driving magnet, the DC tilt can be reduced with high accuracy without creating a cause of the AC tilt.

An optical pickup device according to a tenth aspect of the present invention includes a laser light source for emitting a laser beam for irradiating the optical disc, an objective lens driving device according to any one of the first to ninth aspects, and the optical disc from the optical disc. A light receiving optical system that receives the reflected light and an objective lens control system that outputs a control signal to the objective lens driving device based on a light receiving signal in the light receiving optical system are provided.

Therefore, since this optical pickup device includes the objective lens driving device according to any one of claims 1 to 9, it is possible to perform control with little influence of tilt when driving the objective lens.

An optical disk device according to an eleventh aspect of the present invention comprises a rotary drive system for rotationally driving the optical disc, and an optical pickup device according to the tenth aspect which is provided so as to be movable in a radial direction of the optical disc.

Therefore, this optical disk device is provided with the optical pickup device according to the tenth aspect of the present invention, and the control which is less influenced by the tilt when the objective lens is driven is possible.
It is possible to provide an optical disk device that does not cause a problem even when it is susceptible to tilt such as VD.

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to FIGS. 1 to 5 together with the principle of the present invention. 1 to 3 show the basic structure of an objective lens driving device to which the present invention is applied. FIG. 1 is a plan view, FIG. 2 is a side view, and FIG. 3 is a state before adjusting the rigidity of an elastic fixing portion. FIG. 4 is a front view for explaining the movement of the movable portion when inspecting the tilt amount for adjusting the rigidity of the elastic fixing portion, and FIG. 5 is a front view showing a state after the rigidity of the elastic fixing portion is adjusted. .

First, the basic structure of this embodiment will be described. In this objective lens driving device, the objective lens 1
The objective lens holding member 2 for holding the lens is elastically supported by four wire springs 3 which are rod-shaped elastic supporting members. A focusing coil 4, which is a driving coil wound in a cylindrical shape, is attached to the objective lens holding member 2, and a driving coil wound in a planar shape is formed on one side surface of the cylindrical focusing coil 4. Two certain tracking coils 5 are attached. The objective lens holding member 2, the objective lens 1, the focusing coil 4, the tracking coil 5 and the like form a movable portion 6.

Further, the objective lens driving device has a base 7
Is provided, and the yoke 8a,
8b is integrally formed, and a fixing member 9 is provided on one end side of the base 7.
Is fixed.

The yoke 8a, 8b has a drive magnet 10a,
10b are fixed to face each other, and these driving magnets 10a,
10b is arranged with a gap so that the magnetic flux penetrates into the drive parts of the focusing coil 4 and the tracking coil 5.

Coil terminal boards 11 are fixed to both sides of the objective lens holding member 2, one end side of the wire spring 3 is soldered to the coil terminal board 11, and the other end side of the wire spring 3 is fixed to the fixing member 9. Has been done.

On the back side of the surface of the fixed member 9 facing the movable portion 6, the wire spring 3 fixed to the fixed member 9 is provided.
An elastic substrate 12 having elasticity in a substantially axial direction is fixed. The elastic substrate 12 is formed in an H shape, and the portions protruding in four directions are elastic fixing portions 13 that are independent of each other. Then, the elastic substrate 12 is fixed to the fixing member 9 in a state where only the central portion of the H shape is in contact with the fixing member 9 and each elastic fixing portion 13 has a gap between the elastic fixing portion 13 and the fixing member 9. There is.

Wire spring 3 fixed to fixing member 9
Are provided so as to penetrate through the fixing member 9, and the ends of the wire springs 3 that penetrate through the fixing member 9 are soldered to the four elastic fixing portions 13 one by one.

In FIG. 2, 14 is an optical disk, and 15 is a rising prism.

Of the four wire springs 3 elastically supporting the movable part 6, the wire springs 3 arranged in pairs on both sides of the objective lens 1 in the optical axis direction are fixed to the movable part 6. They are arranged in a substantially V-shape having a narrow width on the open side and a wide width on the side fixed to the fixing member 9 (see FIG. 1). The two wire springs 3 forming a pair in the optical axis direction of the objective lens 1 are arranged in parallel (see FIG. 2).

Here, by adjusting the rigidity of the four elastic fixing portions 13 to which the wire springs 3 are soldered according to the principle described later, the DC of the objective lens 1 can be obtained without causing an AC tilt in the objective lens 1. The tilt can be reduced, and the rigidity of the elastic fixing portion 13 can be adjusted by
For example, this can be done by adjusting the length dimension of the elastic fixing portion 13. As shown in FIG. 5, the length of the elastic fixing portion 13 is adjusted by adhering a part of the elastic fixing portion 13 to the fixing member 9 with an adhesive 16, as shown in FIG. Can be shortened, whereby the rigidity of the elastic fixing portion 13 can be increased.

In such a structure, first, the principle that the DC tilt can be reduced by adjusting the rigidity of the elastic fixing portion 13 to which the wire springs 3 arranged in a substantially V shape are soldered will be described.

In the 4WS type objective lens driving device, each wire spring 3 is moved by focusing and tracking operations.
Axial force is generated in the axial direction of. Thereby, the elastic fixing portion 1
Since a force in the substantially axial direction of the wire spring 3 is applied to 3, the elastic fixing portion 13 is slightly deformed. The deformation direction is shown in FIG.
As shown in FIG. 4, when the movable portion 6 is driven to the plus side in the focusing direction, the soldering points a, b, c, d of the four wire springs 3 with respect to the elastic fixing portions 13 are a and a. The b part is deformed to the front side, and the c part and the d part are deformed to the back side. When the movable part 6 is driven to the plus side in the tracking direction, the a part and the c part are deformed to the back side,
The b portion and the d portion are deformed toward the front side.

On the other hand, when the wire springs 3 are arranged in a substantially V shape, if only one position of the elastic fixing portion 13 to which the end of the wire spring 3 is fixed is displaced in the axial direction of the wire spring 3, The movable part 6 including the objective lens 1 is tilted in the radial direction. For example, when the portion b of the wire spring 3 to be soldered to the elastic fixing portion 13 is deformed to the front side,
As shown in (b), the movable portion 6 including the objective lens 1 tilts in the arrow β direction (the radial direction minus side). Further, when the portion b of the wire spring 3 to be soldered to the elastic fixing portion 13 is deformed to the back side, as shown in FIG. 4A, the movable portion 6 including the objective lens 1 moves in the direction of the arrow α. Tilt to the (plus side in the radial direction).

Utilizing the above phenomenon as shown in FIG. 4, the rigidity of the elastic fixing portions 13 at the four positions are adjusted to each other,
By controlling the amount of deflection in each axial direction,
It is possible to change the inclination of the objective lens 1 by the focusing operation and the tracking operation. That is,
By adjusting the rigidity of each elastic fixing portion 13, the DC force can be adjusted without moving the driving force center of the objective lens driving device.
It is possible to optimize the tilt characteristics.

The specific adjusting method is as follows.

When the movable part 6 tilts to the plus side in the radial direction when the movable part 6 is driven to the plus side in the focusing direction, or when the movable part 6 is driven to the minus side in the focusing direction, the movable part 6 moves. When tilting to the minus side in the radial direction, the rigidity of the elastic fixing portion 13 (see FIGS. 3 and 4) including the soldering points b and d of the wire spring 3 is set to the soldering points a and c. It is made larger than the rigidity of the elastic fixing portion 13 provided with. As a result, tilting to the minus side in the radial direction easily occurs due to driving to the plus side in the focusing direction, so that the tilt to the plus side in the radial direction that originally occurred can be offset.

When the movable part 6 tilts to the minus side in the radial direction when the movable part 6 is driven to the plus side in the focusing direction, or when the movable part 6 is driven to the minus side in the focusing direction, the movable part 6 moves. When tilting to the plus side in the radial direction, the rigidity of the elastic fixing portion 13 having the soldering points a and c of the wire spring 3 is
The rigidity is made larger than the rigidity of the elastic fixing portion 13 including the soldering points b and d. As a result, tilting toward the plus side in the radial direction easily occurs due to driving toward the plus side in the focusing direction, so that the tilt to the minus side in the radial direction that has originally occurred can be offset.

When the movable portion 6 tilts to the minus side in the radial direction when the movable portion 6 is driven to the plus side in the tracking direction, or when the movable portion 6 is driven to the minus side in the tracking direction, the movable portion 6 moves. When tilting to the minus side in the radial direction, the rigidity of the elastic fixing portion 13 provided with the soldering points c and d of the wire spring 3 is set to the rigidity of the elastic fixing portion 13 including the soldering portions a and b. Make it bigger. As a result, the tilt toward the plus side in the radial direction easily occurs due to the driving toward the plus side in the tracking direction, so that the tilt to the minus side in the radial direction that has originally occurred can be offset.

When the movable portion 6 tilts to the radial plus side when the movable portion 6 is driven to the plus side in the tracking direction, or when the movable portion 6 is driven to the minus side in the tracking direction, the movable portion 6 moves. When tilting to the plus side in the radial direction, the rigidity of the elastic fixing portion 13 including the wire spring 3 soldering points a and b is determined by the rigidity of the elastic fixing portion 13 including the soldering points c and d. Make it bigger. As a result, tilting to the minus side in the radial direction is likely to occur due to driving to the plus side in the tracking direction, so that the tilt to the plus side in the radial direction that has originally occurred can be offset.

After assembly, a tilt inspection of the objective lens driving device is performed. For example, when the objective lens driving device is driven to the plus side in the focusing direction, it is tilted to the plus side in the radial direction, and when driven to the plus side in the tracking direction, it is moved to the minus side in the radial direction. If tilted, adjust with the above. That is, as an adjustment included in both and, the rigidity of the elastic fixing portion 13 including the soldering portion b of the wire spring 3 is made larger than the rigidity of the elastic fixing portion 13 including the soldering portion c.

By adjusting the rigidity of the elastic fixing portion 13 as described above, the position of the center of support of the movable portion can be adjusted, and the center of support of the movable portion substantially coincides with the center of the driving force of the objective lens driving device. By adjusting to, the DC tilt can be reduced.

Moreover, since the center of the driving force of the objective lens driving device is not moved in order to reduce the DC tilt, the center of the driving force and the center of inertia of the movable portion 6 are as designed before and after this adjustment. Therefore, it is possible to prevent the occurrence of the AC tilt caused by the shift of the center of the driving force and the center of inertia of the movable portion 6.

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. The same parts as those described in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted (same in the following embodiments).

The basic structure of this embodiment is the same as that of the first embodiment, and a different part is between the elastic fixing part 13 and the fixing member 9 in order to adjust the length of the elastic fixing part 13. The spacer 17 is inserted and fixed to the. In each elastic fixing portion 13, the length dimension of each elastic fixing portion 13 can be adjusted by adjusting the insertion fixing position of the spacer 17 in the radial direction, and the rigidity of each elastic fixing portion 13 is adjusted by the adjustment. be able to.

In such a structure, each elastic fixing portion 1
Since the length of 3 can be adjusted by adjusting the insertion and fixing position of the spacer 17, the length of each elastic fixing portion 13 can be adjusted,
Also, the rigidity of each elastic fixing portion 13 can be easily adjusted based on the length adjustment.

Next, a third embodiment of the present invention will be described with reference to FIG.
It will be described based on. The basic structure of the present embodiment is the second
This embodiment is different from the second embodiment in that the present embodiment is different from the second embodiment in that a plurality of types of spacers 17a, 17b, 1 having different sizes (width widths) are used in the present embodiment.
7c is prepared, and one of the spacers 17a to 17c is selected and inserted and fixed between the elastic fixing portion 13 and the fixing member 9 according to the inspection result of the tilt amount inspection of the movable portion 6. That is the point.

In such a structure, each spacer 17
Since it is not necessary to adjust the insertion position when inserting and fixing a to 17c, spacers 17a to 17c having different sizes are provided.
Can be inserted using the same insertion reference point as a reference, and the length of each elastic fixing portion 13 can be adjusted by inserting and fixing the spacers 17a to 17c, and the rigidity of each elastic fixing portion 13 can be adjusted by adjusting the length. The accuracy can be increased.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
It will be described based on. The basic structure of this embodiment is the first
The difference is that the adhesive 18 is applied to the surface of the elastic fixing portion 13 whose rigidity is to be increased in order to adjust the rigidity of the elastic fixing portion 13.

In such a structure, the elastic fixing portion 13 coated with the adhesive 18 has a large thickness and a high rigidity.

Thus, by applying the adhesive 18 to the surface of the elastic fixing portion 13, the adjustment for increasing the rigidity of the elastic fixing portion 13 can be easily performed.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
It will be described based on. The basic structure of this embodiment is the first
However, in order to adjust the rigidity of the elastic fixing portion 13, a viscoelastic material 19 such as silicon gel is injected between the elastic fixing portion 13 and the fixing member 9 in the same manner as the embodiment of FIG. It was done.

In such a structure, the viscoelastic material 19
The rigidity of the elastic fixing portion 13 at the portion where the is injected becomes high.
Moreover, the rigidity of the elastic fixing portion 13 can be easily adjusted by injecting the viscoelastic material 19.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
A description will be given based on 0. The basic structure of the objective lens driving device of the present embodiment is the same as the conventional objective lens driving device described in FIGS. 19 and 20, and the basic structure will be briefly described.

In this objective lens driving device, the yoke 8
Driving magnet 20 divided into four in a cross shape with respect to a and 8b
a and 20b are fixed. These drive magnets 20
The drive coils (focusing coil 21 and tracking coil 22), which are arranged at positions facing a and 20b and are fixed to the objective lens holding member, are both formed in a planar shape.

The drive magnets 20a, 20b are magnetized in four divisions with the cross-shaped magnetizing boundary lines a, b as a boundary (4-pole magnetizing), and the magnetizing direction is the focusing direction (Y axis). Direction) and a tracking direction (X-axis direction), which is perpendicular to the plane including the biaxial direction (Z-axis direction) and opposite to the adjacent region.

The focusing coil 21 is formed of a planar coil, and two objective coil holding members are provided on both sides of the magnetization boundary line a in the focusing direction. Held in. On the other hand, two tracking coils 22 are provided on both sides of the magnetizing boundary line b in the tracking direction, and are respectively held by the objective lens holding member across the magnetizing boundary line a in the focusing direction.

In this objective lens driving device, the movable portion composed of the objective lens, the objective lens holding member, and the like is substantially symmetrical in the radial direction as in the first to fifth embodiments described above. The wire spring is elastically supported by a wire spring arranged in a V shape, and an end portion of the wire spring is fixed to an elastic fixing portion of an elastic substrate having elasticity in the axial direction of the wire spring.

In such an arrangement, in the objective lens driving device using the quadrupole magnetized driving magnets 20a and 20b, DC tilt occurs due to an assembling error in a state where the movable part is simply assembled, so that the focusing operation is performed. Then, the tilt is inspected by the tracking operation, and DC is detected by the same method as the method described in the first embodiment.
The rigidity of the elastic fixing portion is adjusted so that the tilt becomes smaller.

As a result, according to the motor configuration of this embodiment, since the moment generated by the motor is originally small, the DC tilt can be reduced with high accuracy. Of course, the deviation of the center of the driving force and the center of inertia of the movable part due to the adjustment does not occur, so that the AC tilt characteristic can be kept good.

In each of the above-described embodiments, an example is given in which the elastic substrate 12 formed in the H shape and each of which protrudes in four directions is the elastic fixing portion 13 which is independent of each other. However, the shape of the elastic substrate may be rectangular, and the ends of the four wire springs 3 may be soldered to the four corners of the rectangular elastic substrate. In this case, the four corners to which the ends of the wire springs 3 are soldered are the elastic fixing portions.

Next, a seventh embodiment of the present invention will be described with reference to FIG.
It will be described based on 1. The present embodiment shows an application example to an optical pickup device 32 provided with an objective lens driving device 31 configured as in each of the above-described embodiments. The diffused light emitted from a light source 33 such as a semiconductor laser mounted on the optical pickup device 32 is collimated by the collimator lens 3
It becomes a substantially parallel light by 4. After that, it passes through the beam splitter 35 and is bent by the rising mirror 36.
The collimated light bent by the raising mirror 36 is the objective lens driving device 3 mounted on the optical pickup device 32.
The light enters the objective lens 1 of No. 1 and forms a spot on the optical disc 14.

The light reflected by the spot is reflected by the beam splitter 35.
After passing through the condenser lens 37 and the cylindrical lens 38, the light enters the four-division light receiving element 39. The above-mentioned optical components are arranged so that the reflected light of the spot on the optical disc 14 enters the four-division light receiving element 39. Focusing coil of the objective lens driving device 31, tracking coils 4, 5 (or 21, 22) based on the signal obtained by the four-division light receiving element 39.
The information of the optical disk 14 can be obtained by causing the objective lens 1 to follow the optical disk 14 by driving. A light receiving optical system 40 is configured by the condenser lens 37, the cylindrical lens 38, and the four-division light receiving element 39. Further, an objective lens control system (not shown) that outputs a drive signal to the objective lens drive device 31 based on the light reception signal of the four-division light receiving element 39 is also provided.

Here, the objective lens driving device 31 mounted on the optical pickup device 32 is configured as described in the above-mentioned first to sixth embodiments,
As described above, the objective lens driving device 31 causes the objective lens 1 to follow the optical disc 14 and
Although the information of No. 4 is read, since the objective lens driving device 31 is configured so that the tilt of the objective lens 1 when the movable portion 6 is driven becomes small, it is possible to obtain a good signal.

Next, an eighth embodiment of the present invention will be described with reference to FIG.
2 and FIG. 13. The present embodiment shows an application example to an optical disc drive (optical disc device) equipped with the optical pickup device 32 as described above. First, the pickup module base 43 is installed in the housing 41 of the optical disk drive via the anti-vibration rubber 42. A spindle motor 44 as a rotary drive system for rotating the optical disc 14 is fixed to the pickup module base 43. The optical pickup device 32 is mounted on the seek rail 45 attached to the pickup module base 43. The optical pickup device 32 is movable on the seek rail 45 in the radial direction (radial direction) of the optical disc 14.

Here, the optical pickup device 32 mounted on the optical disk drive is the optical pickup device described in the above-mentioned seventh embodiment, in which the objective lens 1 when the movable part 6 is driven. Since the tilt is reduced, the optical pickup device can obtain good signal characteristics. Therefore, the optical disk drive can satisfactorily read and write data even when handling the optical disk 14 that is easily affected by tilt such as a DVD.

[0100]

According to the objective lens driving device of the first aspect of the present invention, rod-shaped elastic supporting members arranged in pairs on both sides of the objective lens in the optical axis direction are arranged in a substantially V-shape. By adjusting the rigidity of the plurality of elastic fixing portions of the elastic substrate to which the ends of the rod-shaped elastic support members are fixed, the driving force center and the movable portion can be changed without changing the position of the driving force center of the objective lens driving device. The position of the movable part support center can be adjusted so that the position of the movable part support center coincides with the position of the support center, and thus the DC tilt can be reduced and the D
Since the center of the driving force of the objective lens driving device is not moved for the adjustment to reduce the C tilt, the center of the driving force and the center of inertia of the movable portion can be maintained as originally designed before and after this adjustment. Therefore, it is possible to prevent the occurrence of the AC tilt caused by the displacement of the center of the driving force and the center of inertia of the movable portion.

According to the invention described in claim 2, in the objective lens driving device according to claim 1, the plurality of elastic fixing portions corresponding to the plurality of rod-shaped elastic supporting members are formed independently of each other. The rigidity of each elastic fixing portion can be easily adjusted.

According to the third aspect of the invention, in the objective lens driving device according to the first or second aspect, the rigidity of the elastic fixing portion is adjusted by adjusting the length of the elastic fixing portion. Therefore, the rigidity of each elastic fixing portion can be adjusted by a simple adjustment.

According to the invention described in claim 4, in the objective lens driving device according to claim 3, a part of the elastic fixing portion is adhered to the fixing member with an adhesive to adjust the length dimension of the elastic fixing portion. Therefore, the length of each elastic fixing portion can be easily adjusted, and the fine adjustment can be easily performed.

According to the fifth aspect of the invention, in the objective lens driving device according to the third aspect, the spacer is inserted and fixed between the elastic fixing portion and the fixing member to adjust the length dimension of the elastic fixing portion. Therefore, the length of each elastic fixing portion can be adjusted by adjusting the insertion fixing position of the spacer.

According to the sixth aspect of the present invention, in the objective lens driving device according to the fifth aspect, the spacer inserted and fixed between the elastic fixing portion and the fixing member is inspected during tilt amount inspection of the movable portion. Since the size differs according to the result, it is not necessary to adjust the insertion position when inserting and fixing each spacer, spacers of different sizes can be inserted with the same insertion reference point as a reference, and each elastic fixing It is possible to improve the accuracy of rigidity adjustment by adjusting the length of the portion.

According to the invention described in claim 7, in the objective lens driving device according to claim 1 or 2, the rigidity of the elastic fixing portion is adjusted by applying an adhesive on the surface of the elastic fixing portion. Therefore, the rigidity of the elastic fixing portion can be easily adjusted.

According to the eighth aspect of the invention, in the objective lens driving device according to the first or second aspect, the rigidity of the elastic fixing portion is adjusted by injecting a viscoelastic material between the elastic fixing portion and the fixing member. Since it is performed by doing so, the rigidity of the elastic fixing portion can be easily adjusted.

According to the invention described in claim 9, in the objective lens driving device according to any one of claims 1 to 8, even when a quadrupole magnetized drive magnet is used as the drive magnet, the AC tilt It is possible to reduce the DC tilt with high accuracy without creating a cause of occurrence of.

According to the optical pickup device of the tenth aspect of the present invention, since the objective lens driving device of any one of the first to ninth aspects is provided, it is possible to perform control with little influence of tilt when driving the objective lens. .

According to the optical disc apparatus of the eleventh aspect of the present invention, the optical pickup apparatus of the tenth aspect is provided,
Since it is possible to perform control with little influence of tilt when the objective lens is driven, it is possible to provide an optical disk device that does not cause any trouble even when it is easily affected by tilt such as a DVD.

[Brief description of drawings]

FIG. 1 is a plan view showing an objective lens driving device according to a first embodiment of the present invention.

FIG. 2 is a side view thereof.

FIG. 3 is a front view showing a state before adjusting the rigidity of the elastic fixing portion.

FIG. 4 is a front view for explaining the movement of the movable portion when inspecting the tilt amount for adjusting the rigidity of the elastic fixing portion.

FIG. 5 is a front view showing a state after adjusting the rigidity of the elastic fixing portion.

FIG. 6 is a front view showing an objective lens driving device according to a second embodiment of the present invention.

FIG. 7 is a front view showing an objective lens driving device according to a third embodiment of the present invention.

FIG. 8 is a front view showing an objective lens driving device according to a fourth embodiment of the present invention.

FIG. 9 is a front view showing an objective lens driving device according to a fifth embodiment of the present invention.

FIG. 10 is an exploded perspective view showing a driving motor which is a part of the objective lens driving device according to the sixth embodiment of the present invention.

FIG. 11 is a schematic configuration diagram showing an optical pickup device according to a seventh embodiment of the present invention.

FIG. 12 is a schematic plan view showing an optical disc drive of an eighth embodiment of the present invention.

FIG. 13 is a side view thereof.

FIG. 14 is a perspective view showing an objective lens driving device of a first conventional example.

15A and 15B are schematic views showing the occurrence of tilt, FIG. 15A is a plan view in an ideal case in which no tilt occurs, and FIG. 15B is a plan view in the case where tilt occurs.

FIG. 16 is a schematic front view when tilt occurs.

FIG. 17 is a plan view showing an objective lens driving device of a second conventional example.

FIG. 18 shows an objective lens driving device of a third conventional example,
(A) is a plan view and (b) is a side view thereof.

FIG. 19 is an exploded perspective view showing a drive motor which is a part of an objective lens drive device of a fourth conventional example.

FIG. 20 is an explanatory diagram thereof, in which (a) is a horizontal cross-sectional view of the coil seen from the focusing direction, (b) is a characteristic diagram showing a magnetic field distribution in the tracking direction, and (c) is a diagram showing the coil and the driving magnet. FIG. 3A is a front view showing an arrangement relationship, FIG. 6D is a characteristic view showing a magnetic field distribution in a focusing direction, and FIG.

[Explanation of symbols]

1 Objective lens 2 Objective lens holding member 3 Rod-shaped elastic support member 4, 5 drive coil 6 moving parts 7 base 8a, 8b yoke 9 fixing member 10a, 10b Driving magnet 12 Elastic substrate 13 Elastic fixing part 14 Optical disc 16 Adhesive 17 Spacer 17a, 17b, 17c spacer 18 Adhesive 19 Viscoelastic member 21, 22 Drive coil 31 Objective lens driving device 32 Optical pickup device 33 Laser light source 40 Light receiving optical system 44 rotary drive system

Claims (11)

[Claims] 1. A movable part having an objective lens for forming a light spot, an objective lens holding member for holding the objective lens, and a drive coil, a fixed member fixed to a base, and one end side of the movable part. A plurality of rod-shaped elastic supporting members that elastically support the movable portion with respect to the base by being fixed to the fixing member and the other end side being fixed to the fixing member, and attached to a yoke provided on the base. And a driving magnet that forms a magnetic circuit together with the yoke by being closely opposed to the driving coil, and is arranged as a pair on both sides in the optical axis direction of the objective lens. The rod-shaped elastic support member is arranged in a substantially V shape in which the width on the side fixed to the movable portion is narrow and the width on the side fixed to the fixed member is wide, and the rod-shaped elastic support member faces the movable portion of the fixed member. The end of the rod-shaped elastic support member on the side of the fixing member is fixed to the back side of the surface, and an elastic substrate having elasticity in the substantially axial direction of the rod-shaped elastic support member is fixed, and the elastic substrate has the rod-shaped elasticity. An objective lens driving device, wherein a plurality of elastic fixing portions, which are portions to which an end portion of a supporting member is fixed, are formed, and rigidity of the elastic fixing portions is adjusted. 2. The objective lens driving device according to claim 1, wherein the plurality of elastic fixing portions to which end portions of the plurality of rod-shaped elastic supporting members are fixed are formed independently of each other. . 3. The objective lens driving device according to claim 1, wherein the rigidity of the elastic fixing portion is adjusted by adjusting a length dimension of the elastic fixing portion. 4. The objective lens according to claim 3, wherein a length of the elastic fixing portion is adjusted by adhering a part of the elastic fixing portion to the fixing member with an adhesive. Drive. 5. The objective lens according to claim 3, wherein a length dimension of the elastic fixing portion is adjusted by inserting and fixing a spacer between the elastic fixing portion and the fixing member. Drive. 6. The spacer, which is inserted and fixed between the elastic fixing portion and the fixing member, has a different size according to an inspection result of a tilt amount inspection of the movable portion. The objective lens driving device according to claim 5. 7. The objective lens drive device according to claim 1, wherein the rigidity of the elastic fixing portion is adjusted by applying an adhesive to the surface of the elastic fixing portion. 8. The adjustment of the rigidity of the elastic fixing portion is performed by injecting a viscoelastic material between the elastic fixing portion and the fixing member. Objective lens driving device. 9. The driving magnet is divided into four regions in a cross shape in the surface of the drive magnet, and is perpendicular to a plane including the biaxial directions of the focusing direction and the tracking direction and in a direction opposite to an adjacent region. The driving coil is magnetized, and two focusing coils are provided on both sides of a magnetization boundary line in the focusing direction in the vicinity of the surface of the drive magnet, and the two focusing coils are provided across the magnetization boundary line in the tracking direction. A coil and two tracking coils located on both sides of the magnetizing boundary line in the tracking direction near the surface of the driving magnet and provided across the magnetizing boundary line in the focusing direction. The objective lens drive device according to claim 1. 10. A laser light source that emits laser light for irradiating an optical disc, an objective lens driving device according to claim 1, and a light receiving optical system that receives reflected light from the optical disc. An optical pickup device comprising: an objective lens control system for outputting a control signal to the objective lens driving device based on a light reception signal in the light receiving optical system. 11. An optical disc apparatus comprising: a rotary drive system for rotationally driving an optical disc; and an optical pickup device according to claim 10, which is provided so as to be movable in a radial direction of the optical disc.