JP2000149292A - Objective lens drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an objective lens drive device stably supplying a current to a tilting coil tilting/driving an objective lens and hardly displacing a light spot position on an optical disk recording surface even when the objective lens is tilted in the optical disk radial direction. SOLUTION: The objective lens drive device is constituted so that a movable part arranged with the objective lens 1 is supported with six pieces of conductive elastic support members 8, and by arranging four pieces of the conductive elastic support members on the optical disk side in the optical axial direction of the objective lens 1, and arranging two pieces of them on the opposite side, a support central position P is brought near to the main point position S of the objective lens 1.

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 used for an optical disk device.

[0002]

2. Description of the Related Art An example of an objective lens driving device used in an optical disk device is disclosed in, for example, JP-A-6-25140.
Japanese Unexamined Patent Application Publication No. 5 or JP-A-6-139600 is known.

FIGS. 9, 10 and 11 show the structure of a basic objective lens driving device. 9 is a sectional view of the objective lens driving device according to the prior art in the tangential direction of the optical disk, FIG. 10 is a side view of the objective lens driving device according to the prior art, and FIG. Show.

An objective lens 1 is disposed on an upper surface of a lens holder 2, a focusing coil 3 is wound on a side surface of the lens holder 2, and a tracking coil 4 and an objective lens 1 are provided on a side surface of the lens holder 2. A tilting coil 9 that tilts and drives in the direction is attached.

[0005] The four parallel linear elastic support members 8 include:
The lens holder 2 having one end fixed to the lens holder 2 and the other end fixed to the fixing part, and the objective lens 1 is disposed,
It is elastically supported so that it can move in the focusing direction and the tracking direction, and can also tilt in the radial direction of the optical disk.

On the other hand, a magnetic circuit composed of a yoke 5 (5a, 5b) and a magnet 6 (6a, 6b) is arranged on a fixed portion to which one end of the elastic support member 8 is fixed, and the focusing is performed. The drive current flowing through the coil 3, the tracking coil 4, and the tilt coil 9 is arranged to act on the magnetic flux generated from the magnetic circuit. Further, on the upper surface of the lens holder 2 on which the objective lens 1 is arranged, an inclination detector 7 for detecting the inclination of the optical disk is arranged.

At the time of the focusing control, an electric current is appropriately supplied to the focusing coil 3 in accordance with the deflection of the recording surface of the optical disk to operate the objective lens 1 in the optical axis direction.
The light beam spot can follow the recording surface of the optical disk. At the time of tracking control, the tracking coil 4 corresponds to the eccentricity and meandering of the track of the optical disk.
The objective lens 1 can be operated in a direction perpendicular to the optical axis by supplying an appropriate current to the optical disk so that the spot of the light beam follows the track of the optical disk. Further, with respect to the tilt of the optical disk, it is possible to appropriately supply a current to the tilt coil 9 based on the signal from the tilt detector 7 to drive the objective lens 1 to tilt corresponding to the tilt of the optical disk.

[0008]

In recent years, higher recording densities have been promoted in optical disk devices. One method of realizing higher recording density is to narrow the light beam more narrowly and to reduce the spot diameter on the recording surface of the optical disk. The spot diameter is λ, the wavelength of the light beam,
If the numerical aperture of the objective lens 1 is NA, it is proportional to λ / NA.

Therefore, in general, the light beam is narrowed down by reducing the wavelength λ of the light beam and setting the numerical aperture NA of the objective lens 1 to a value larger than that of the conventional one.
A method corresponding to high recording density has become mainstream. Increasing the NA of the objective lens 1 makes it possible to narrow the light beam more narrowly, but on the other hand, there is a tendency that the optical characteristics deteriorate due to the inclination between the optical disk and the objective lens 1. Therefore, it is necessary to suppress the tilt angle between the optical disk and the objective lens within a certain value by some means.

In the conventional objective lens driving device,
As shown in FIGS. 9, 10, and 11, the relative tilt angle between the optical disk and the objective lens 1 is detected by the tilt detector 7, and the current is appropriately supplied to the tilt coil 9 based on the detection result. The configuration is such that the relative tilt angle between the objective lens 1 and the optical disk is kept constant.

[0011] However, in the case of the objective lens driving device according to the prior art, means for supplying current to each driving coil is not specified. In general, there are only four elastic support members 8 made of conductive members, and therefore, a maximum of two drive coils can supply current by the conductive elastic support members 8. Temporarily focusing coil 3
And a conductive elastic supporting member 8 for the tracking coil 4
When a current is supplied through the tilt coil 9, a lead wire dedicated to the tilt coil 9 is required for the tilt coil 9 as disclosed in JP-A-6-139600.

However, since this lead wire has a poor assembling workability and a large adverse effect on the operation inclination characteristics of the objective lens 1, a high-precision objective lens driving device capable of performing tilt control in the radial direction of the optical disk. Is an inappropriate configuration.

When a direct current or a low-frequency component drive current is supplied to the tilt coil 9 via a lead wire,
As shown in FIG. 1, the movable part on which the objective lens 1 is disposed
Support center P determined by rigidity balance of four elastic support members
The tilting operation is performed with the tilting center as the tilting center. Therefore, the objective lens 1 arranged near the upper surface of the lens holder 2 distant from the support center P is displaced in the radial direction of the optical disk, that is, in the tracking direction due to the tilting operation.

The objective lens 1 has two principal points, which are optical centers, one each on the optical disk side and on the laser light source side, a total of two. Therefore, even when the objective lens 1 tilts, if the tilting is performed around one of the principal points,
The light spot position existing on the recording surface of the optical disk is less likely to be displaced.

However, in the above-mentioned prior art, the objective lens 1
Since the principal point position S, which is the optical center of the objective lens 1, and the tilt center position are separated from each other, when the objective lens 1 is displaced in the tracking direction by the tilting operation, the principal point position S of the objective lens 1 is also displaced, As a result, the position of the light spot on the recording surface of the optical disk is also displaced in the tracking direction.

Therefore, the displacement amount of the light spot becomes a disturbance to the tracking control system, and it is impossible to make the light spot position follow the track of the optical disk correctly. As a result, it is difficult to accurately read or write a signal from the optical disk. Becomes difficult.

As described above, in the configuration of the conventional objective lens driving device described above, the tilting operation in the radial direction of the optical disk is performed around the support center position P determined by the rigidity balance of the four elastic support members. In addition, the principal point position S, which is the optical center of the objective lens 1, and the tilting center position in the radial direction of the optical disk are greatly separated.

Therefore, when the objective lens 1 is tilted in accordance with the tilt of the optical disk so as to keep the relative tilt angle between the optical disk and the objective lens 1 constant, the light focused on the optical disk recording surface by the objective lens 1 is The spot is displaced in the tracking direction. As a result, the amount of displacement of the light spot in the tracking direction due to this tilting operation becomes a disturbance to the tracking control system, and there has been a problem that signals cannot be read or written from the optical disk accurately.

Further, since no consideration is given to the means for supplying current to each drive coil, lead wires and the like are required in addition to the four conductive elastic support members, so that assembly workability and stable operation characteristics can be obtained. Had a problem.

The present invention has been made in order to solve the above-mentioned problems, and considers means for supplying current to each drive coil,
Even if stable operation characteristics are secured and the objective lens is tilted and driven in the radial direction of the optical disk, the displacement of the light spot position on the recording surface of the optical disk is small, and therefore, the tilting operation of the objective lens 1 causes disturbance to the tracking control system. It is an object of the present invention to realize an objective lens driving device that is unlikely to be driven.

[0021]

In order to achieve the above object, a first means comprises an objective lens for condensing a light beam on an optical disk, and a force for driving the objective lens in the direction of the optical axis. And at least one focusing coil for generating a force, and at least one or more tracking coils for generating a force for driving the objective lens in a direction perpendicular to the optical axis thereof, the focusing coil, the tracking coil, and the objective lens A movable part including a lens holder or the like holding the like, an elastic support means having one end fixed to the movable part and elastically supporting the movable part,
A fixing portion to which the other end of the elastic support means is fixed, at least one or more magnets for generating a driving force on the focusing coil and the tracking coil, and a tilt drive of the objective lens in a radial direction of the optical disc; A tilting means, wherein the elastic support means is constituted by six elastic support members.

The second means includes an objective lens for condensing the light beam on the optical disk, at least one focusing coil for generating a force for driving the objective lens in the optical axis direction, A movable section including at least one or more tracking coils for generating a force for driving the objective lens in a direction perpendicular to the optical axis, the focusing coil, a lens holder for holding the tracking coil, the objective lens, and the like. An elastic support means having one end fixed to the movable section and elastically supporting the movable section; a fixed section to which the other end of the elastic support means is fixed; and a driving force generated in the focusing coil and the tracking coil. At least one or more magnets, and the objective lens or the movable At least one set of tilt coils for tilting and driving the optical disc in the radial direction, and a magnet for generating a magnetic flux with respect to the tilt coils, wherein the elastic support means is constituted by six elastic support members. It is characterized by the following.

According to a third aspect, in the first or second aspect, the six elastic supporting members are formed of a conductive member.

A fourth means is that in any one of the first to third means, the six elastic supporting members are four on the optical disk side in the optical axis direction of the objective lens. It is characterized in that two are arranged on opposite sides, respectively.

A fifth means is the device according to any one of the first to fourth means, wherein the elastic support member disposed at a position closest to the optical disk among the elastic support members, At least one of the principal points of the objective lens is arranged between the elastic support member and the elastic support member arranged at a position.

According to a sixth means, in any one of the first to fourth means, at least one of the principal points of the objective lens is arranged at a position distant from the objective lens, and the elastic support member At least one of the principal points of the objective lens is located between the elastic support member disposed closest to the optical disk and the elastic support member disposed farthest from the optical disk. It is characterized by being arranged.

According to a seventh means, in any one of the first to sixth means, the position of at least one principal point of the objective lens is located at the center of the tilting operation of the movable part in the radial direction of the optical disk. It is characterized in that they are configured to substantially match.

An eighth means is the device according to any of the first to sixth means, wherein the position of at least one principal point of the objective lens is a support center position determined by the rigidity balance of the six elastic support members. Is characterized by being substantially matched to

In a ninth aspect, in any one of the first to eighth aspects, the tilt coil is wound around the objective lens substantially at a center, and an outer peripheral portion of the tilt coil in a direction tangential to the optical disk. Wherein the focusing coil is disposed, and the tracking coil is disposed on an outer peripheral portion of the focusing coil in a tangential direction of the optical disc, and the tilt driving magnet for generating a magnetic flux acting on the tilt driving coil includes the tilt driving coil. And a magnet that generates a magnetic flux acting on the focusing coil and the tracking coil is disposed at a position rotated by 90 degrees with respect to the tilt drive magnet. It is a feature.

The tenth means includes an objective lens for condensing the light beam on the optical disk, and two focusing coils arranged approximately symmetrically, one on each side of the objective lens in the radial direction of the optical disk. A movable portion including at least one or more tracking coils for driving the objective lens in a direction perpendicular to the optical axis thereof, a focusing lens, a lens holder for holding the tracking coil, the objective lens, and the like; An elastic support means having one end fixed to the section and elastically supporting the movable section; a fixed section to which the other end of the elastic support means is fixed; a magnet configured to generate a magnetic flux acting on the focusing coil; Circuit, comprising a magnetic circuit including a magnet or the like that generates a magnetic flux acting on the tracking coil, The serial focusing coil, it is possible to supply a drive current independently and,
The elastic support means is constituted by six elastic support members.

According to an eleventh aspect, in the tenth aspect, the six elastic supporting members are formed of a conductive member.

The twelfth means includes the tenth or eleventh means.
Means, four of the six elastic support members are arranged on the optical disk side in the optical axis direction of the objective lens, and two are arranged on the opposite side of the optical disk. is there.

The thirteenth means includes the tenth to twelfth
In any of the means, between the elastic support member disposed at a position closest to the optical disk side of the elastic support member, between the elastic support member disposed at a position farthest from the optical disk, At least one of the principal points of the objective lens is arranged.

The fourteenth means includes the tenth to twelfth
In any one of the above means, at least one of the principal points of the objective lens is arranged at a position distant from the objective lens, and the elastic support member is arranged at a position closest to the optical disk side of the elastic support member. At least one of the principal points of the objective lens is disposed between a supporting member and the elastic supporting member disposed farthest from the optical disc.

The fifteenth means includes the tenth to fourteenth means
Wherein the position of at least one principal point of the objective lens substantially coincides with the center position of the movable portion tilting in the radial direction of the optical disk. It is.

The sixteenth means includes the tenth to fourteenth means
In any one of the above means, the position of at least one principal point of the objective lens substantially coincides with the support center position determined by the rigidity balance of the six elastic support members. Things.

A seventeenth means is the device according to any one of the first to sixteenth means, wherein at least two of the six elastic support members have an axial rigidity of another four. The rigidity of the elastic support member is set to be smaller than the rigidity in the axial direction.

In an eighteenth aspect, based on the seventeenth aspect, at least two of the six elastic support members have a coil spring-like portion.

[0039] The nineteenth means is any one of the first to eighteenth means, wherein, among the six elastic members,
At least two or more elastic support members have a diameter or a cross-sectional area different from other elastic support members.

In a twentieth means, in any one of the first to nineteenth means, the material or Young's modulus of at least two or more of the six elastic support members is the other. It is different from the elastic support member.

[0041]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment of the objective lens driving device according to the present invention will be described. 1, 2 and 3
Is a top view showing the first embodiment of the present invention,
FIG. 3 is a cross-sectional view of a principal part in the tangential direction of the optical disc (A-A cross section) and a cross-sectional view of a main part in the radial direction of the optical disc (BB cross section).

In FIG. 1, FIG. 2 and FIG.
Is disposed on the upper surface of the lens holder 2. A tilting coil 9 is wound around the center of the lens holder 2 with the objective lens 1 substantially at the center of its winding.

On both sides of the tilting coil 9 in the tangential direction of the optical disk, the focusing coil 3 as an air core coil is disposed so as to be sandwiched between the arm portions of the lens holder 2.
Further, a tracking coil 4 is provided outside the focusing coil 3 in the tangential direction of the optical disk to the lens holder 2.
It is arranged to hang on. As described above, the movable portion is constituted by the objective lens 1, the lens holder 2, the focusing coil 3, the tracking coil 4, the tilt coil 9, and the like.

The movable section is supported by six elastic support members 8, one end of which is fixed to the movable section and the other end is fixed to the fixed section. Further, the elastic support member 8 is made of a conductive material, and the focusing coil 3 and the tracking coil 4 are
And the tilt coil 9 are electrically connected to each other, so that a current can be supplied to the focusing coil 3, the tracking coil 4, and the tilt coil 9 from the fixed portion via the elastic support member 8. I have.

As shown in FIGS. 1 and 3, four elastic support members 8 (8a, 8b, 8b, 8b, 8b, 8b, 8b) are provided on the optical disk side in the optical axis direction of the objective lens 1 as shown in FIGS.
8c, 8d), and two (8e, 8d)
f) It is arranged. Thus, the conductive elastic support member 8
Is arranged, the position of the support center position P of the movable portion determined by the rigidity balance of the six elastic support members 8 in the optical axis direction of the objective lens 1 is set to the elastic support members 8a, 8b, 8
The height is close to the height at which c and 8d are arranged, and consequently it approaches the principal point position S which is the optical center position of the objective lens 1. That is, the overall rigidity balance of the plurality of elastic support members 8 arranged in the optical axis direction of the objective lens 1 is determined by the rigidity determined by the number or cross-sectional area and material of the elastic support members 8. By making the rigidity larger than the rigidity on the opposite side, it becomes possible to bring the support center position P of the movable portion closer to the principal point position S which is the optical center position of the objective lens.

Therefore, even if the movable part tilts about the support center position P, the principal point position S of the objective lens 1 hardly displaces in the tracking direction, and as a result, the light is condensed by the objective lens 1. The position of the light spot on the recording surface of the optical disk thus hardly displaced in the tracking direction due to the tilting operation.

A magnetic circuit composed of a yoke 5 and a magnet 6 is arranged at a fixed portion where one end of the elastic support member 8 is fixed. Two sets of magnetic circuits each composed of magnets 6a, 6b and a yoke 5 are arranged so as to sandwich the outer peripheral portions of the tracking coil 4 and the focusing coil 3 in the tangential direction of the optical disk. Are arranged such that the effective line portion of the

Further, two magnets 6 for tilting drive are provided.
The movable parts c and 6d are arranged on the outer peripheral part of the movable part in the radial direction of the optical disk. The magnetic flux emitted from the magnets 6c and 6d and the current flowing through the tilt coil 9 generate tilt driving force. ing.

Although not shown, the optical disk and the objective lens 1
Is detected by calculating the amount of jitter from the signal read from the optical disk. A tilt drive circuit for generating a tilt drive signal is arranged so as to reduce the amount of jitter, and an appropriate drive current is supplied to the tilt coil 9 by a signal from the tilt drive circuit. I have.

Next, in the first embodiment of the present invention,
The operation will be described. The optical pickup optically generates a focusing error signal for the vertical runout of the optical disk, and an appropriate drive current for the focusing coil 3 is supplied from the focusing drive circuit to the focusing coil 3 via the conductive elastic support member 8 in response to the signal. Focusing control is performed so that the light spot of the light beam supplied and collected by the objective lens 1 is always positioned on the recording surface of the optical disk.

Also, for the meandering and eccentricity of the truck,
In the optical pickup, a tracking error signal is generated optically, and an appropriate drive current is supplied from the tracking drive circuit to the tracking coil 4 via the conductive elastic supporting member 8 in accordance with the signal, and is collected by the objective lens 1. The tracking control is performed such that the light spot of the light beam is always positioned on the track of the optical disk.

In this way, the focusing control and the tracking control are executed, and it becomes possible to read a signal from the optical disk.

On the other hand, the signal read from the optical disk contains an error (jitter) in the time axis direction whose magnitude is mainly affected by the relative tilt angle between the optical disk and the objective lens 1. Therefore, by appropriately tilting the objective lens 1 in accordance with the tilt of the optical disk, it is possible to suppress the jitter amount.

Conversely, the amount of jitter contained in the read signal is calculated, and a tilt drive signal for the objective lens 1 is created so as to minimize the amount of jitter, and the tilt coil 9 is driven in accordance with the tilt drive signal. By supplying an appropriate tilt drive current via the conductive elastic support member 8, tilt control (tilt control) of the movable portion of the objective lens driving device, that is, tilt control of the objective lens 1 can be performed.

At this time, the entire movable portion performs a tilting operation about the support center position P determined by the rigidity balance of the six elastic support members 8 by the tilting driving force. Accordingly, the end surface of the objective lens 1 disposed at a position away from the support center position P toward the optical disk moves in the tracking direction at the same time as the tilting operation in the radial direction of the optical disk.

However, in the objective lens driving device according to the present embodiment, the principal point position S, which is the optical center position of the objective lens 1, is substantially coincident with or close to the support center position P. Moves in the tracking direction, but the principal point position S of the objective lens 1 hardly displaces in the tracking direction.

Accordingly, the spot position on the recording surface of the optical disk focused by the objective lens 1 hardly moves. As a result, even if the objective lens 1 is tilted in the radial direction of the optical disc while the focusing control and the tracking control are operated, the light spot position on the recording surface of the optical disc hardly moves due to the tilting operation. Disturbance on the control system is small, and as a result, a normal signal with small jitter can be read or written from the optical disk. FIGS. 4, 5, and 6 are top plan views showing a second embodiment of the present invention and cross-sectional views (sections AA) of main parts in the tangential direction of the optical disk.
FIG. 3 is a sectional view (BB section) of a main part in the radial direction of the optical disc.

In FIG. 4, FIG. 5, and FIG.
Is disposed on the upper surface of the lens holder 2. In the lens holder 2, focusing coils 3a and 3b are arranged on both sides in the radial direction of the optical disc, and tracking coils 4 are arranged on both sides in the tangential direction of the optical disc to constitute a movable portion. The movable part has six elastic support members 8
a, 8b, 8c, 8d, 8e, 8f,
One end of the elastic support member 8 is fixed to the movable part, and the other end is fixed to the fixed part.

The elastic support member 8 is made of a conductive material, and is electrically connected to the focusing coils 3a, 3b and the tracking coil 4 disposed on the movable portion, respectively. Via the conductive elastic support member 8, the focusing coil 3
a, 3b and the tracking coil 4 can be supplied with current.

The focusing coils 3a and 3b are wired independently of each other, so that different currents can be applied. The magnetic flux acting on the focusing coils 3a, 3b is
It is generated by a magnetic circuit composed of 6d and yokes 5c, 5d. On the other hand, the magnetic flux acting on the tracking coil 4 is generated by the magnets 6a and 6b and the yokes 5a and 5b.
Generated by a magnetic circuit composed of

As in the first embodiment, also in the second embodiment, the six elastic support members 8 for elastically supporting the movable portion are provided with the objective lens 1 as shown in FIGS. In the optical axis direction, four optical disks (8a, 8b,
8c, 8d), and two (8e, 8d)
f) It is arranged.

By arranging the elastic support members 8 in this manner, the support center position P of the movable portion determined by the rigidity balance of the six elastic support members 8 can be adjusted by the elastic support members 8a and 8a.
8b, 8c and 8d are located near the height at which they are arranged, and consequently approach the principal point position S which is the optical center position of the objective lens 1.

Therefore, similarly to the first embodiment, the position of the light spot on the recording surface of the optical disk focused by the objective lens 1 hardly displaces in the tracking direction due to the tilting operation.

Next, the operation of the second embodiment of the present invention will be described. The optical pickup optically generates a focusing error signal for the vertical run-out of the optical disk, and in response to the signal, a drive current having substantially the same magnitude is applied to the focusing coils 3a and 3b from the focusing drive circuit. It is supplied via the support member 8 and the focusing control is performed.

Also, for the meandering and eccentricity of the truck,
In the optical pickup, a tracking error signal is generated optically, and an appropriate drive current is supplied from the tracking drive circuit to the tracking coil 4 via the conductive elastic support member 8 in accordance with the signal, and tracking control is performed.

In this manner, the focusing control and the tracking control are executed, so that signals can be read from the optical disk.

The focusing coils 3a and 3b are arranged on both sides of the movable portion in the radial direction of the optical disk and are independently wired, so that the focusing coils 3a and 3b have different driving currents or different driving directions. A current is applied to both coils (3a, 3a).
b) By generating a difference in the driving force generated between
The movable portion on which the objective lens 1 is disposed can be tilted and driven in the radial direction of the optical disk.

Accordingly, as described above, a tilt drive signal for the objective lens 1 is created so that the amount of jitter included in the read signal is minimized, and the focusing coils 3a and 3b have different directions in accordance with the tilt drive signal. Alternatively, the objective lens 1 can be tilted and driven in the radial direction of the optical disc by applying drive currents having different magnitudes in addition to the focusing drive current, and tilt control of the objective lens 1 can be performed. At this time, the entire movable portion performs a tilting operation around a support center position P determined by the rigidity balance of the six elastic support members 8 by the tilting driving force. Also in the present embodiment, the principal point position S, which is the optical center position of the objective lens 1, is substantially coincident with or close to the support center position P. Therefore, even if the tilting operation is performed, the principal point position S of the objective lens 1 is not changed. Is hardly displaced in the tracking direction.

As a result, similarly to the first embodiment, since the light spot position on the recording surface of the optical disk hardly moves due to the tilting operation, disturbance to the tracking control system is small, and jitter from the optical disk is small. Normal signal reading or writing becomes possible.

FIG. 7 is a top view showing a third embodiment of the present invention. In FIG. 7, the characteristic feature is that a coil-shaped portion is provided so as to reduce the axial rigidity of two (8b, 8d) of the six elastic support members 8. Originally, the elastic support member 8 that supports the movable part can restrain the movable part with four if it only supports it,
The fifth and sixth elastic support members 8 are unnecessary.

Therefore, the fifth and sixth elastic support members (for example, 8b and 8d) may be excessively restrained.
Therefore, in the third embodiment, the axial rigidity of the fifth and sixth elastic support members (8b, 8d) is reduced by providing a coil-shaped portion for the purpose of removing the adverse effect due to the excessive constraint. The above-mentioned excessive restraint is prevented.

FIG. 8 is a sectional view of a main part in the radial direction of an optical disk showing a fourth embodiment according to the present invention. In FIG. 8, four elastic support members 8 arranged on the optical disk side with respect to the optical axis direction of the objective lens 1 are arranged side by side in the optical axis direction of the objective lens 1. It goes without saying that the effects of the present invention can be obtained even if the elastic support members 8a, 8b, 8c, 8d are arranged as described above. Further, the present invention is not limited to the example of the arrangement of the elastic support members 8 shown in FIG.
It is needless to say that the effects of the present invention can be obtained even if 8b and 8c, 8d are arranged in an oblique positional relationship.

[0074]

As described above, according to the present invention, the movable portion on which the objective lens is disposed is supported by the six conductive elastic supporting members, and the focusing coil, the tracking coil, and the tilting coil are electrically conductive. It can be connected to the conductive elastic support member and can appropriately supply each drive current to each coil via this conductive elastic support member, and a power supply component such as a lead wire that causes a variation in operation characteristics becomes unnecessary, and a stable There is an effect that operation characteristics can be realized.

Further, four elastic support members are arranged on the optical disk side of the objective lens in the optical axis direction and two elastic support members are arranged on the opposite side of the optical disk, so that the center position of the support of the movable part and the optical characteristics of the objective lens are improved. It is possible to bring the principal point position closer to the center closer, and even if the objective lens is tilted and driven in the radial direction of the optical disk, the principal point position hardly displaces in the tracking direction, and as a result, the light spot on the optical disk The position is hardly displaced in the tracking direction. Therefore, there is also an effect that disturbance to the tracking control system due to the tilting drive of the objective lens can be suppressed.

As a result, it is possible to tilt the objective lens in the radial direction of the optical disk while operating the focusing control and the tracking control, thereby controlling the tilt to an optimum value, thereby reading and writing an accurate signal with small jitter from the optical disk. There is an effect that becomes possible.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of a principal part in the tangential direction of the optical disk showing the first embodiment of the objective lens driving device according to the present invention.

FIG. 3 is a cross-sectional view of a principal part of an optical disk in a radial direction showing a first embodiment of an objective lens driving device according to the present invention.

FIG. 4 is a top view showing a second embodiment of the objective lens driving device according to the present invention.

FIG. 5 is a sectional view of a principal part in the tangential direction of an optical disk showing a second embodiment of the objective lens driving device according to the present invention.

FIG. 6 is a sectional view of a main part of an optical disk in a radial direction showing a second embodiment of the objective lens driving device according to the present invention.

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

FIG. 8 is a sectional view of a principal part of an optical disk in a radial direction showing a fourth embodiment of the objective lens driving device according to the present invention.

FIG. 9 is a sectional view of a conventional objective lens driving device in a tangential direction of an optical disk.

FIG. 10 is a side view of a conventional objective lens driving device.

FIG. 11 is a sectional view of a conventional objective lens driving device in a radial direction of an optical disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Lens holder 3 Focusing coil 4 Tracking coil 5 Yoke 6 Magnet 7 Tilt detector 8 Elastic support member 9 Tilt coil

Continued on the front page (72) Inventor Michio Miura 1st Kitano, Majo, Mizusawa City, Iwate Prefecture Inside Hitachi Media Electronics Co., Ltd. F term (reference) 5D118 AA04 AA13 AA24 BA01 CA11 CA13 CD02 CD03 DC03 EA02 EB13 ED08 FA12

Claims (20)

[Claims] An objective lens for condensing a light beam on an optical disk, at least one or more focusing coils for generating a force for driving the objective lens in the optical axis direction, A movable portion including at least one or more tracking coils for generating a force for driving in a direction perpendicular to an axis, the focusing coil, a lens holder for holding the tracking coil, the objective lens, and the like, and the movable portion Resilient support means having one end fixed to the movable part and elastically supporting the movable part; a fixed part to which the other end of the elastic support means is fixed; and at least one for generating a driving force on the focusing coil and the tracking coil. The magnet, the tilting means for tilting and driving the objective lens in the radial direction of the optical disc, The objective lens driving device, wherein the elastic support means is constituted by six elastic support members. 2. An objective lens for condensing a light beam on an optical disk, at least one or more focusing coils for generating a force for driving the objective lens in the optical axis direction, A movable part including at least one or more tracking coils for generating a force for driving in a direction perpendicular to an axis, a focusing coil, a lens holder for holding the tracking coil, the objective lens, and the like, and the movable part Resilient support means having one end fixed to the movable part and elastically supporting the movable part; a fixed part having the other end fixed to the elastic support means; and at least one for generating a driving force on the focusing coil and the tracking coil. The above-mentioned magnet and the objective lens or the movable portion disposed on the movable portion are connected to the optical disk. At least one set of tilt coils driven to tilt in the radial direction and a magnet for generating a magnetic flux to the tilt coils are provided, and the elastic support means is constituted by six elastic support members. Objective lens driving device. 3. The method according to claim 1, wherein
The objective lens driving device, wherein the six elastic support members are formed of a conductive member. 4. The optical recording medium according to claim 1, wherein the six elastic support members are four on the optical disk side in the optical axis direction of the objective lens and two on the opposite side to the optical disk. And an objective lens driving device, wherein the objective lens driving device is arranged. 5. The elastic support member according to claim 1, wherein the elastic support member is arranged at a position closest to the optical disk, and the elastic support member is arranged at a position most distant from the optical disk. An objective lens driving device, wherein at least one of the principal points of the objective lens is disposed between the elastic support member and the elastic support member. 6. The object according to claim 1, wherein at least one of the principal points of the objective lens is arranged at a position distant from the objective lens, and the most of the elastic support members At least one of the principal points of the objective lens is arranged between the elastic support member arranged at a position close to the optical disk and the elastic support member arranged at a position farthest from the optical disk. An objective lens driving device, characterized in that: 7. The apparatus according to claim 1, wherein a position of at least one principal point of the objective lens substantially coincides with a center position of a tilting operation of the movable portion in a radial direction of the optical disk. An objective lens driving device characterized in that: 8. The apparatus according to claim 1, wherein a position of at least one principal point of the objective lens substantially coincides with a support center position determined by a rigidity balance of the six elastic support members. An objective lens driving device characterized by being configured as described above. 9. The focusing coil according to claim 1, wherein the tilting coil is wound around the objective lens substantially at a center, and the focusing coil is wound around an outer peripheral portion of the tilting coil in a tangential direction of the optical disk. Is disposed, and the tracking coil is disposed on an outer peripheral portion of the focusing coil in the tangential direction of the optical disc, and a tilt driving magnet for generating a magnetic flux acting on the tilt driving coil is provided on the optical disc radius of the tilt driving coil. An object which is arranged at an outer peripheral portion in a direction, and a magnet which generates a magnetic flux acting on the focusing coil and the tracking coil is arranged at a position rotated by 90 degrees with respect to the tilt driving magnet. Lens drive. 10. An objective lens for condensing a light beam on an optical disk, two focusing coils arranged approximately symmetrically on both sides of the objective lens in a radial direction of the optical disk, and the objective lens is provided. A movable part including at least one or more tracking coils driven in a direction perpendicular to the optical axis, a lens holder for holding the focusing coil, the tracking coil, the objective lens, and the like, and one end fixed to the movable part An elastic support means for elastically supporting the movable portion, a fixed portion to which the other end of the elastic support means is fixed, a magnetic circuit including a magnet for generating a magnetic flux acting on the focusing coil, and the tracking device. A magnetic circuit including a magnet or the like that generates a magnetic flux acting on the coil; The coil, it is possible to supply driving current to each independently, and said elastic support means, the objective lens driving device, characterized in that it is constituted by six elastic supporting members. 11. The objective lens driving device according to claim 10, wherein the six elastic support members are formed of a conductive member. 12. The six elastic support members according to claim 10, wherein the six elastic support members are four on the optical disk side in the optical axis direction of the objective lens, and two on the opposite side to the optical disk. An objective lens driving device, which is disposed. 13. The elastic support member according to claim 10, wherein the elastic support member is arranged at a position closest to the optical disk side among the elastic support members.
An objective lens driving device, wherein at least one of the principal points of the objective lens is arranged between the elastic support member and the elastic support member arranged farthest from the optical disk. 14. The method according to claim 10, wherein at least one of the principal points of the objective lens is provided.
Are arranged at positions away from the objective lens, and
The principal point of the objective lens between the elastic support member disposed closest to the optical disk among the elastic support members and the elastic support member disposed farthest from the optical disk. An objective lens driving device, wherein at least one is disposed. 15. The apparatus according to claim 10, wherein a position of at least one principal point of the objective lens substantially coincides with a center position of a tilting operation of the movable portion in a radial direction of the optical disc. An objective lens driving device characterized in that: 16. The objective lens according to claim 10, wherein at least one principal point position of the objective lens substantially coincides with a support center position determined by a rigidity balance of the six elastic support members. An objective lens driving device characterized by being configured as described above. 17. The six elastic support members according to claim 1, wherein at least two of the six elastic support members have an axial rigidity of at least two.
An objective lens driving device, wherein the rigidity of the elastic support member is set to be smaller than the rigidity in the axial direction. 18. The objective lens driving device according to claim 17, wherein at least two of the six elastic support members have a coil spring-like portion. 19. The elastic support member according to claim 1, wherein at least two or more of the six elastic members have different diameters or cross-sectional areas from other elastic support members. An objective lens driving device, characterized in that: 20. The elastic support member according to claim 1, wherein a material or a Young's modulus of at least two of the six elastic support members is different from that of another elastic support member. An objective lens driving device, which is different.