JPH0981947A - Objective lens driving device of optical disk device and objective lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an objective lens driving device and an objective lens having a structure preventing the deviation of optical axis i.e., the deviation of a spot on a recording surface in an optical disk device mounting the objective lens on a movable plate through a conductive elastic wire and having plural kinds of objective lenses. SOLUTION: This device is provided with an objective lens changeover device 7 for shifting a lens holder 4 in the tracking direction against a movable plate so that one of optical axes of plural kinds of objective lenses 5a, 5b is made coincident with the optical axis of only one light ray emitted from an optical part 3. The positions of the respective objective lenses 5a, 5b are set so that the necessary driving range of other objective lens 5b falls within the necessary driving range of the objective lens 5a largest in necessary driving range in the focusing direction. The plural kinds of objective lenses 5a, 5b corresponding to plural kinds of optical disks 2 are integrally formed.

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 disc device which projects a light spot on an optical disc to record and / or reproduce optical information, and an objective lens used in the device.

[0002]

2. Description of the Related Art In recent years, as an optical disk device, development of an optical head device capable of comprehensively processing optical disks having different purposes and different optical characteristics such as different thickness and recording density is emphasized. As an example of such an optical head device, in Japanese Patent Laid-Open No. 6-333255, it is possible to record / reproduce a plurality of types of optical discs having different thicknesses.
A plurality of types of objective lenses corresponding to the respective optical discs are provided, and these objective lenses are set so that the light spot converges on the recording surface when the target optical disc is set. At the same time, a light flux obtained by splitting the light from the light emitting part common to the objective lens is incident,
It has been proposed that the reflected light from the optical disc is focused, that is, the objective lens can obtain a luminous flux having a sufficient light amount only when the target optical disc is set.

Further, Japanese Patent Laid-Open No. 7-37259 discloses that
In order to support multiple types of optical discs and to switch and use multiple types of objective lenses, by switching the angle of the mirror provided in the middle of the beam of light to the objective lens, only the objective lens corresponding to the set optical disc will have a luminous flux. The one configured to be incident is proposed.

In addition, as a conventional objective lens driving device for an optical disc having different optical characteristics, a shaft protruding in the focus direction is provided on a movable table which is moved and set in the tracking direction, and a disk-shaped lens is attached to the shaft. By attaching the holder rotatably, and fixing to the lens holder two objective lenses corresponding to the optical disc of different optical characteristics with a space in the circumferential direction, by rotating the lens holder in the circumferential direction, There is a structure in which the objective lens is switched.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As described in Japanese Patent Publication No. 255-255, an objective lens switching means is not provided and a light amount of a predetermined amount or more can be obtained only from an optical disc set to a target reflected light. Since the light flux is incident,
For example, when two objective lenses and the same laser power are used, the objective emission power is 1/2 and the light quantity on the light receiving element surface is 1
Since it is reduced to / 4, a large laser power is required as compared with the case where there is only one objective lens.

On the other hand, as described in Japanese Unexamined Patent Publication No. 7-37259, one in which the light flux is incident on only one of the objective lenses by changing the angle of the mirror has an advantage that it is not necessary to increase the laser power. . However, in the case of selectively using the objective lens for entering the light flux in this way, the angle shift of the mirror causes the tens of μm on the light receiving element surface.
There is also a problem in that the optical axis is likely to be displaced, such as the case where m is out of the spot and the signal cannot be sufficiently recognized.

Further, in the structure in which the objective lens is switched by rotating the lens holder about the axis,
The lead wire for connecting to the circuit on the movable table is connected to the tracking coil and the focusing coil on the objective lens by the rotation when selecting the objective lens, and the physical force is applied to the lead wire. There is a problem that it is easy to break. Further, since it is necessary to move the objective lens in the tracking direction, it is unknown which objective lens is selected. Also, by rotating the lens holder to switch the objective lens, in this switched state,
Since the facing position between the permanent magnet fixed to the movable table side and the lens holder differs depending on the switching of the objective lens, at least two types of tracking coils have to be provided and switched for use in correspondence with optical disks having different optical characteristics. Further, since a switch for switching the tracking coil is required, there is a problem that the circuit configuration becomes complicated.

In view of the above-mentioned problems, the present invention provides an objective lens driving device for an optical disc device, which selects and uses only the objective lens facing the set optical disc among a plurality of types of objective lenses. It is an object of the present invention to provide an objective lens driving device and an objective lens having a structure that does not have the above-mentioned inconvenience in the dynamic type and does not cause the deviation of the optical axis, that is, the deviation of the spot on the recording surface and the light receiving surface.

[0009]

In order to achieve this object, the invention according to claim 1 mounts an optical unit on a movable table which is moved in the tracking direction of an optical disk and whose position is controlled, for recording and reproduction. In an optical disc device that performs at least one of the above, a plurality of types of objective lenses corresponding to a plurality of types of optical discs are arranged in the tracking direction and fixed to a lens holder, and the optical axis of the only light beam emitted from the optical unit is An objective lens switching device for shifting the lens holder in the tracking direction with respect to the movable table is provided so that one optical axis of a plurality of types of objective lenses coincides with each other.

According to the second aspect of the present invention, a plurality of types of objective lenses corresponding to a plurality of types of optical discs are arranged in the tracking direction and fixed to the lens holder, and the objective lens having the largest required driving range in the focus direction is required. It is characterized in that the positions of the respective objective lenses are set so that the necessary driving ranges of the other objective lenses are within the driving range.

A third aspect of the present invention relates to an objective lens used in the objective lens driving device, wherein a plurality of types of objective lenses corresponding to a plurality of types of optical discs are integrally formed.

According to a fourth aspect of the present invention, the lens holder is mounted on the movable table via a conductive elastic wire.

[0013]

According to the first aspect of the present invention, the objective lens switching device shifts and positions the lens holder to which the objective lens is fixed in the tracking direction.
The objective lens to be used is matched with the optical axis of one light beam, and the objective lens to be used is selected by this.

According to the second aspect of the present invention, among the plurality of types of objective lenses, the positions of the respective objective lenses are set so that the driving ranges of the other objective lenses fall within the largest driving range of the required driving range in the focusing direction. Since the setting is made, the required drive range for all the objective lenses falls within the required drive range of the objective lens having the largest required drive range.

According to the third aspect of the present invention, since the plurality of types of objective lenses are integrally formed, there is no risk of inconsistencies in the directions of the optical axes due to mounting errors of the plurality of objective lenses.

In the invention of claim 4, after selecting one of the objective lenses, the base end side of the conductive elastic wire is fixed to the movable table side, and the lens holder is focused by the elasticity of the conductive elastic wire. Controlled and tracking controlled.

[0017]

1A is a plan view showing an embodiment of an objective lens driving device according to the present invention, and FIG. 1B is a side view thereof. In FIG. 1, reference numeral 1 denotes a movable table which is moved in the tracking direction of the optical disk 2 and whose position is controlled. On the movable table 1, a light emitting section made of a laser or the like, a light receiving section for reflected light from the optical disk 2, etc. are provided. The optical unit 3 is installed.
Reference numeral 4 is a lens holder, and 5a and 5b are objective lenses of different types fixed on the lens holder 4 for a plurality of optical discs of different types.

The lens holder 4 is mounted on the movable table 1 via a driving device base 6 fixed to the movable table 1, an objective lens switching device 7 installed thereon, and a conductive elastic wire 8. Mounted. The objective lens switching device 7 includes a fixing member 9 fixed on the drive device base 6, and
As shown in the cross-sectional view of (A), a rectangular support rod 10 having a rectangular cross section that is movably inserted into a rectangular through hole 9a provided in the fixing member 9 in the tracking direction, and a central portion of the through hole 9a. A coil 11 fixed to the inner wall of the enlarged portion 9b, a permanent magnet 12 fixed to the central portion of the support rod 10 so as to penetrate the coil 11, and fixed near the left and right ends of the support rod 10. Substrate 13 and drive base 6
And stoppers 14a and 14b fixed so as to face both end surfaces of the support rod 10. The base end portions of the upper and lower two conductive elastic wires 8 are fixed to the substrates 13 fixed to the left and right of the support rod 10 by soldering, and the lens is attached to the front end portions of the left and right two wire rods 8. Both left and right sides of the holder 4 are fixed, the lens holder 4 is elastically supported by the four wire rods 8, and is indicated by an arrow T in the tracking direction (FIG. 1 (A) and FIG. 2 (C), (D)). ) And the focus direction (indicated by arrow F in FIG. 1B).

The lens holder 4 has a quadrangular shape, and the objective lenses 5a and 5b are provided at the center of the lens holder 4.
It is fixed side by side in the tracking direction. Further, rectangular focusing coils 15a and 15b and tracking coils 16a and 16b are fixed to both ends of the lens holder 4 in the direction perpendicular to the tracking direction, that is, in the tangential direction of the optical disk 2, respectively. The coil moves in unison with the lens holder 4. 17a,
Reference numeral 17b is a permanent magnet, and the permanent magnets 17a and 17b are provided.
Is a yoke 18a, 18b fixed to the drive unit base 6 so as to face the focusing coils 15a, 15b and the tracking coils 16a, 16b, respectively.
Are fixedly attached to each. The focusing coils 15a and 15b are electrically connected in series, are connected to two of the four conductive elastic wire rods 8, and the tracking coils 16a and 16b are also connected in series to connect the other conductive elastic wire rods 8 to each other. It is electrically connected to the two.

Reference numeral 19 is a reflecting mirror fixed to the movable table 1. The reflecting mirror 19 makes the light beam 20 from the optical section 3 incident on the objective lens 5a or 5b, and the optical disk 2
The reflected light from is returned to the optical unit 3.

In FIG. 1A, 21a and 21b are
The switch is a switch that detects the position of the support rod 10 by being pushed by the support rod 10 to operate.

In this objective lens driving device, when the coil 11 of the objective lens switching device 7 is energized in the direction a of FIG. 2 (A), the support rod 10 shifts as shown by the arrow b, and FIG. 3 (A). As shown, one stopper 14a fixed on the drive unit base 6 and one end of the support rod 10 are in contact with the knob of the switch 21a. In this state, as shown in FIG. The optical axis of one objective lens 5a coincides with the optical axis of the only light ray 20 emitted from the optical unit 3. When the coil 11 is energized in the direction opposite to the direction a, as shown in FIG. 3B, the support rod 10 shifts in the direction opposite to the arrow b, and the opposite end of the support rod 10 moves to another position. In this state, the stopper 14b and the knob of the switch 21b are brought into contact with each other. In this state, as shown in FIG.
The optical axis of the other objective lens 5b coincides with the optical axis of 0. By generating an electric signal by the operation of the switches 21a and 21b, it becomes clear whether or not a predetermined objective lens has been selected and moved to the correct position, so that malfunction can be prevented. The deviation of the optical axes of the objective lenses 5a and 5b with respect to the optical axis of the light beam 20 is set to be within a range of ± 0.1 mm.

In this way, by shifting and positioning the objective lenses 5a and 5b together with the lens holder 4, the optical axis of the objective lens 5a or 5b is changed to the light beam 2 from the optical section 3.
By adopting a configuration in which the optical axis coincides with 0, compared with the case where the angle of the reflection mirror is changed to select the objective lens as in the conventional example, the switching device for selecting the objective lens has higher positioning accuracy. Easy to match the optical axis without being required
It can be realized with less error.

In this way, after the objective lenses 5a and 5b are shifted, in order to move the objective lenses 5a and 5b to proper positions according to the surface shake and eccentricity of the optical disk 2, the focusing coils 15a and 15b and the tracking coil 16 are provided.
A and 16b are energized via the conductive elastic wire rod 8 to perform focus control and tracking control. That is, the tracking coil 16a or 16b interlinks with the magnetic flux of the permanent magnet 17a or 17b, and the conductive elastic wire 8 is applied to the tracking coil 16a or 16b.
By energizing through the lens holder 4, the lens holder 4 is positionally controlled in a minute range in the tracking direction,
When the focusing coils 15a and 15b are energized, the lens holder 4 is positionally controlled in the focus direction due to the interlinkage with the magnetic flux of the permanent magnets 17a and 17b, and the light flux is controlled to be concentrated on the target spot.

In the present invention, since the lens holder 4 is moved together with the conductive elastic wire 8, the objective lens 5a,
When switching 5b, the focusing coil 15a,
15b or the tracking coils 16a and 16b and the conductive elastic wire 8 are connected to each other by applying no unreasonable force to the connecting lead wire, and there is no risk of disconnection of the lead wire. When the substrate 13 and the drive device base 6 are connected by a lead wire, this lead wire has a sufficient mounting space and is not twisted due to rotation, so there is no possibility of disconnection. Moreover, since the conductive elastic wire 8 is moved together with the lens holder 4 to switch the objective lenses 5a and 5b, the objective lens 5a and the objective lens 5a are fixed with the support rod 10 fixed.
Focus control and tracking control of 5b are performed (in the case of the lens holder rotation type, focus control,
According to the tracking control, the lens holder slides in the axial direction about the axis and rotates about the axis), and which of the objective lenses 5a and 5b is selected is detected by the switches 21a and 21b. Is detectable,
The switching state of the objective lens can be displayed reliably. Also,
Since one type of tracking coils 16a and 16b can be commonly used corresponding to the two types of objective lenses 5a and 5b, and a switch for switching the tracking coils 16a and 16b is not required, the circuit configuration can be simplified. .

Here, as shown in FIGS. 3 (A) and 3 (B), the focusing coils 15a and 15b and the tracking coils 16a and 16b are in the tracking direction no matter which the position of the lens holder 4 is switched to. The widths of the permanent magnets 17a and 17b in the tracking direction are set to the moving amount of the lens holder 4 so that the focusing coils 15a and 15b and the tracking coil 16 face the permanent magnets 17a and 17b, respectively.
By setting the width to be equal to or more than the width of a and 16b, the force generated by the action of the coil current and the magnetic flux upon the focusing coils 15a and 15b and the tracking coils 16a and 16b is applied to the lens holder 4. The acting point is constant regardless of the change in the position of the lens holder 4. This prevents the rotational force from acting on the lens holder 4 due to the disagreement between the action point of the electromagnetic force and the center of gravity of the lens holder 4, and the objective lens 5
The optical axes of a and 5b are prevented from tilting, and the optical axis of the light beam 20 can be matched with the optical axes of the objective lenses 5a and 5b.

When the present invention is carried out, the focusing coil 15a, 15b for driving the lens holder 4 and the tracking coils 16a, 16b are mounted on the driving device base 6.
The permanent magnets 17a and 17b on the lens holder 4 side.
May be fixed. In the case of the reverse arrangement, the widths of the focusing coil and the tracking coil in the tracking direction are equal to or larger than the sum of the width of the permanent magnet fixed to the lens holder 4 side in the tracking direction and the amount of movement in the tracking direction. By doing so, the inclination of the lens holder 4 can be prevented for the reason described above.

In the objective lens switching device 7, electromagnets are used as the stoppers 14a and 14b in FIG. 1, a magnetic body is used as the support rod 10, and the support rod 10 made of a magnetic body is attracted by either electromagnet. You may make it position. Alternatively, the support rod 10 may be moved by a plunger. Also, the support rod 1
0 may have a circular cross section instead of a rectangular cross section. Also,
After the support rod 10 is shifted, the support rod 10 does not move to the stopper 14a even if the current is not continuously applied to the coil 11.
Alternatively, the objective lens 5a or 5b is always contacted with the objective lens 5a or 5b.
May be provided with a mechanism for holding the.

FIG. 4 illustrates an example of installation of the objective lenses 5a and 5b in the lens holder 4 in the focus direction according to the present invention. As shown in FIG.
When the thickness and the set position of A and the optical disc 2B are deviated by the width indicated by Z1, and the size of the required drive range due to the energization of the focusing coils 15a and 15b of the corresponding objective lenses 5a and 5b is different, one objective lens 5a is assumed. Is set to the position indicated by the solid line, the other objective lens 5b is set to the position indicated by the alternate long and two short dashes line, and the positions of the end portions on the optical disc side are set to c and d
4B, the objective lens 5b is compared with the required drive range Z3 (e is the neutral point) of the objective lens 5a having the larger required drive range, as shown in FIG. 4B.
The required drive range Z4 (where f is its neutral point) deviates from the required drive range of the objective lens 5a, and the overall required drive range is Z5, which requires a wide drive range.

Therefore, as shown by the solid line in FIG. 4 (A), the objective lens 5b is divided by the difference Z2 closer to the optical disc than the optical disc side outermost end g and the optical disc side outermost end c of the objective lens 5a. Just get closer (here, Fig. 4 (A)
L1 and L2 are working distances, which are gaps between the objective lenses 5a and 5b and the optical discs 2A and 2B, respectively, so that as shown in FIG. 4C, the required drive range Z4 of the objective lens 5b ( (h is the neutral point)
Can be within the required drive range Z3 of the objective lens 5a.

In this way, by disposing the objective lens in which the necessary driving device for another objective lens is housed within the necessary driving range of the objective lens that maximizes the necessary driving range, the objective lenses 5a and 5b as a whole can be obtained. Of the conductive elastic wire 8 and the like, thereby suppressing the inclination of the lens holder 4 due to the excessive bending of the conductive elastic wire 8 and the like, whereby the optical axis of the light beam 20 and the optical axes of the objective lenses 5a and 5b are reduced. The gap can be suppressed. Further, by reducing the required drive range of the lens holder 4, the load on the objective lens driving device can be reduced. Note that such a relative positional relationship of the objective lenses can be applied to a case where the objective lens is selected by using the movable reflecting mirror.

FIG. 5A shows an example in which the objective lenses 5a and 5b are separately arranged in the lens holder 4 one by one.
(B) shows that the objective lenses 5a and 5b are integrally formed according to the present invention. According to the lens mounting structure of FIG. 5 (A), the mounting surfaces A of the respective objective lenses 5a and 5b,
Since a mounting angle error with respect to B occurs between the objective lenses 5a and 5b, it becomes difficult to align the optical axes P1 and Q1 in a fixed direction. On the other hand, as shown in FIG. 5B, if the two objective lenses 5a and 5b are collectively formed, the number of mounting surfaces C is one, and the deviations of the optical axes P2 and Q2 are formed. Since it is only a time error and the above-mentioned mounting error does not occur, it is possible to easily align the optical axis in a fixed direction, and as a result, it is possible to reduce the deviation between the light beam and the optical axis of the objective lens. it can. Also,
The distance between the centers of the lenses in the tracking direction when the objective lenses are arranged one by one can be reduced from the distance t1 in the case of the divided arrangement shown in FIG. 5A to t2 shown in FIG. 5B. The amount of movement of the lens holder 4 in the tracking direction can be shortened, and the scale of the lens holder 4 and the objective lens switching device 7 can be reduced.

FIG. 6 shows another embodiment of the present invention in which the shaft 22 serving as a guide for the movement of the movable table 1 is attached to the support rod 1.
The support rod 10A is also made of a magnetic material and is also used as a guide of 0A, and the support rod 10A is attracted by the electromagnet 23a or 23b fixed on the drive unit base 6 fixed on the movable table 1, thereby making the lens holder 4 Moves together with the conductive elastic wire rod 8 and, as a result, the objective lens 5a,
5b can be switched. With such a structure shared by the shafts 22, the structure can be simplified and the size can be reduced.

In the present invention, the lens holder 4 is not supported cantilevered by the conductive elastic wire 8 as shown in the embodiment, but the conductive elastic wire 8 whose both ends are supported by the drive device base 6 is used. The lens holder may be supported at the intermediate portion. Further, the optical disk to which the present invention is applied may be not only optical recording but also magneto-optical recording. Further, the drive device base 6 may be formed as a part of the movable table 1.

[0035]

According to the first aspect, a plurality of types of objective lenses corresponding to a plurality of types of optical disks are arranged in the tracking direction and fixed to the lens holder, and the optical axis of the only light beam emitted from the optical section is set. , One of the plurality of types of objective lenses
Since the objective lens switching device that shifts the lens holder in the tracking direction with respect to the movable table is provided so that the two optical axes coincide with each other, the alignment of the objective lens may be performed only in the tracking direction, and the optical axis shifts. That is, it is possible to provide an objective lens driving device that does not cause spot deviations on the recording surface and the light receiving surface.

Further, since the tracking coil can be commonly used for a plurality of objective lenses and a switch for switching the tracking coils is not required, the circuit structure can be simplified.

According to the second aspect, a plurality of types of objective lenses corresponding to a plurality of types of optical discs are arranged in the tracking direction and fixed to the lens holder, and the plurality of types of objective lenses have the most necessary driving range in the focus direction. Since the position of each objective lens is set so that the required drive range of the other objective lenses is within the large objective lens range, the required drive range of the plurality of objective lenses can be narrowed, as a result, The deviation between the optical axis and the optical axis of the objective lens can be suppressed. Further, by reducing the required drive range of the lens holder, the load on the objective lens driving device can be reduced.

According to the third aspect, since a plurality of types of objective lenses corresponding to a plurality of types of optical discs are integrally formed, it is possible to easily align the optical axes of the respective objective lenses in a fixed direction. The deviation between the light beam and the optical axis of the objective lens can be reduced. Moreover, since the center-to-center distance of the objective lens can be reduced, the amount of movement of the lens holder in the tracking direction can be shortened, and the scale of the lens holder can be reduced.

According to the fourth aspect, since the lens holder is moved together with the conductive elastic wire, an excessive force is applied to the connecting lead wire between the focusing coil or the tracking coil and the conductive elastic wire when the objective lens is switched. There is no risk of lead wire breakage. Further, since the configuration is such that the conductive elastic wire is moved together with the lens holder to switch the objective lens, focus control and tracking control of the objective lens are performed with the support rod fixed, and any objective lens is selected. It is possible to detect whether or not the objective lens is switched, and it is possible to reliably display the switching state of the objective lens.

[Brief description of drawings]

FIG. 1A is a plan view showing an embodiment of an objective lens driving device according to the present invention, and FIG. 1B is a partially cutaway side view thereof.

2A is a cross-sectional view showing a part of the objective lens switching device of the present embodiment, FIG. 2B is a perspective view showing a coil used in the objective lens switching device, and FIGS. FIG. 6 is a perspective view of a reflecting mirror and an objective lens for explaining an objective lens switching operation in the present embodiment.

3A and 3B are plan views of an objective lens driving device for explaining an objective lens switching operation in the present embodiment.

FIG. 4A is a diagram illustrating an installation example of an objective lens in a focus direction in the present embodiment, and FIG. 4B is a diagram illustrating an objective lens when the positions of the two optical disc side end portions of the objective lenses are aligned. FIG. 3C is a plan view showing a drive range, and FIG. 3C is a plan view showing a necessary drive range of the objective lens when the position of the one end of the objective lens on the optical disc side is brought close to the optical disc side.

5A is a sectional view showing an example in which one objective lens is divided and arranged in a lens holder, and FIG. 5B is a sectional view according to the present invention.
It is sectional drawing which shows what formed one objective lens integrally.

FIG. 6 is a plan view showing another embodiment of the objective lens driving device of the present invention.

[Explanation of symbols]

1: movable table, 2: optical disc, 3: optical part, 4: lens holder, 5a, 5b: objective lens, 6: drive device base, 7: objective lens switching device, 8: conductive elastic wire,
9: fixing member, 10: support rod, 11: coil, 1
2: permanent magnet, 13: substrate, 14a, 14b: stopper, 15a, 15b: focusing coil, 16a,
16b: tracking coil, 17a, 17b: permanent magnet, 18a, 18b: yoke, 19: reflection mirror, 2
0: Ray, 21a, 21b: Switch, 22: Shaft, 23a, 23b: Electromagnet

Claims (4)

[Claims] 1. An optical unit is mounted on a movable table, which is moved in the tracking direction of an optical disk and whose position is controlled, for recording.
In an optical disc device that performs at least one of reproduction, a plurality of types of objective lenses compatible with a plurality of types of optical discs are used.
Fixed to the lens holder side by side in the tracking direction, with respect to the optical axis of the only light beam emitted from the optical unit,
An objective lens driving device for an optical disk device, comprising an objective lens switching device for shifting the lens holder in the tracking direction with respect to the movable table so that one optical axis of the plurality of types of objective lenses coincides with each other. apparatus. 2. An optical unit is mounted on a movable table which is moved in the tracking direction of an optical disc and whose position is controlled for recording.
In an optical disc device that performs at least one of reproduction, a plurality of types of objective lenses compatible with a plurality of types of optical discs are used.
The objective lenses are arranged side by side in the tracking direction and fixed to the lens holder, and the position of each objective lens is set so that the required drive range of the other objective lens falls within the required drive range of the objective lens with the largest required drive range in the focus direction. An objective lens driving device for an optical disc device. 3. An optical unit is mounted on a movable table which is moved in the tracking direction of an optical disk and whose position is controlled for recording.
An objective lens for an optical disc device, wherein a plurality of types of objective lenses corresponding to a plurality of types of optical discs are integrally formed in an objective lens used for an optical disc device that performs at least one of reproduction. 4. An objective lens driving device for an optical disc device according to claim 1 or 2, or an objective lens driving device for an optical disc device having an objective lens according to claim 3, wherein the lens holder is mounted on the movable table. An objective lens driving device for an optical disk device, which is mounted via a conductive elastic wire.