JPH1021570A - Optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce signals recorded in an optical disk having different system while decreasing the production cost. SOLUTION: A controller 57 performs control so as to set switches 51, 53, 54 and 56 to specified terminals, cause a semiconductor laser element 11 to emit reading lights and cause a semiconductor laser element 31 not to emit any reading lights. A tracking control driver 52 drives, based on the TE signal, a lens holder 70 via a tracking coil 71 and scanning the reading lights converged by an objective lens 13 on the recording track of an optical disk. A focus control driver 55 drives, based on the FE signal, the lens holder 70 via a focusing coil 72.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing apparatus suitable for use in a digital video disk reproducing apparatus.

[0002]

2. Description of the Related Art Conventionally, an optical pickup for reproducing an optical disk has a two-axis actuator which can move a semiconductor laser element as a light emitting means and an objective lens for irradiating a laser from the semiconductor laser element onto the optical disk in two axial directions. A photodiode for detecting return light from the optical disk; and a photodiode based on a detection signal of the photodiode.
And a servo circuit for driving and controlling the axis actuator in the focusing direction and the tracking direction.

[0003] The biaxial actuator comprises, for example, a lens holder supported axially movable about a support shaft extending perpendicularly to a signal recording surface of an optical disk and rotatably around the shaft. An objective lens has an optical axis held parallel to the support axis at a position eccentric to the support axis of the holder, and a biaxial base to which the support axis is attached.

In the biaxial actuator, a focusing coil is wound around a cylindrical outer peripheral surface of a lens holder, and a pair of tracking coils is wound around the outer surface of the focusing coil opposite to each other. Have been. On the other hand, a pair of yokes made of a magnetic material are provided on the biaxial base so as to face the focusing coil and the tracking coil.

In the above optical pickup,
Each coil is supplied with a drive voltage controlled by a tracking servo and a focus servo, so that a magnetic flux generated in each coil interacts with a magnetic flux of a yoke made of a magnetic material. , And slides along the support shaft. This allows the objective lens held eccentrically from the center of the lens holder to move in the tangential direction due to the rotation of the lens holder, to move in the tracking direction substantially conveniently, and to slide by the movement of the lens holder. By moving in the direction, it moves in the focusing direction conveniently.

Therefore, the return light from the optical disk accurately forms a spot on the light receiving surface of the photodiode,
The reproduction signal of the optical disk is detected based on the detection signal from the photodiode.

[0007]

By the way, in such an optical disk reproducing apparatus, when reproducing an optical disk of a different system, the focal position of light on the optical disk is different, and the recorded signal cannot be reproduced properly. . Therefore, for example, in order to play back two different types of optical disks, two optical pickups are used.
There has been proposed an optical disc reproducing apparatus for reproducing signals recorded on an optical disc by switching between two optical pickups.

However, the optical disk reproducing apparatus having such a structure requires two biaxial drivers for driving each optical pickup, so that the circuit scale becomes large. There has been a problem that the number of relay lines connecting the two-axis driver has increased, and the production cost has increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical disc reproducing apparatus capable of reproducing a signal recorded on an optical disc of a different system while suppressing production costs. With the goal.

[0010]

In order to solve the above-mentioned problems, an optical disk reproducing apparatus according to the present invention controls two two-axis actuators for driving two objective lenses, respectively, and controls the two two-axis actuators. And a two-axis driver for performing tracking and focusing.

In the optical disk reproducing apparatus, a two-axis driver controls the two two-axis actuators to perform tracking and focusing.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. The present invention
The optical disc reproducing apparatus is suitable for reproducing data recorded on optical discs of two different types.

As shown in FIG. 1, for example, as shown in FIG. 1, an optical pickup 10 for reading data recorded on an optical disc from the lower side when the optical disc is loaded, an optical pickup 10 according to the first embodiment, An error signal generation circuit 20 for generating an error signal based on an output signal from the optical pickup 10; an optical pickup 30 for reading data recorded on an optical disc from above; and an error signal generation based on an output signal from the optical pickup 30 And an optical pickup control circuit 50 for controlling the optical pickup 10 or the optical pickup 30. Then, the optical pickup control circuit 5
0 selects one of the optical pickup 10 and the optical pickup 30, and performs tracking control and focus control of the selected optical pickup.

More specifically, the optical pickup 10 includes a semiconductor laser element 11, a polarizing beam splitter 12, an objective lens 13, a photodiode 14, and a lens holder 70 for supporting the objective lens 13.

The semiconductor laser device 11 is a light emitting device utilizing recombination light emission of a semiconductor, and is used as a light source. The beam emitted from the semiconductor laser device 11 is guided to the polarization beam splitter 12.

The polarizing beam splitter 12 is disposed with its reflection surface inclined at 45 degrees with respect to the optical axis.
The beam from the semiconductor laser element 11 is separated from the return light from the signal recording surface of the optical disk. That is, the beam from the semiconductor laser element 11 is transmitted to the polarization beam splitter 12.
The reflected light is reflected by the reflecting surface of the polarization beam splitter 1
2 is transmitted.

The objective lens 13 is a convex lens, and irradiates a beam from the polarization beam splitter 12 onto a predetermined track on a signal recording surface of an optical disk.

Here, the objective lens 13 is supported by a lens holder 70, and can be moved in a focusing direction and a tracking direction by controlling a biaxial actuator described later by a biaxial driver.

The photodiode 14 receives the return light beam transmitted through the polarization beam splitter 12 at a light receiving section,
A signal corresponding to the light beam is output.

Here, as shown in FIGS. 2 and 3, the optical pickup 10 has a biaxial base 60 to which a support shaft 61 extending perpendicular to the signal recording surface of the optical disk is attached.
And a substantially circular lens holder 70 supported in a manner movable in the axial direction and rotatable around the axis.

A biaxial base 60 has a pair of arc-shaped focusing yokes 62 facing each other around a support shaft 61.
Are disposed, and a pair of focusing magnets 63 are disposed inside thereof. The biaxial base 60 has
A pair of arc-shaped tracking yokes 64 facing each other around the support shaft 61 are arranged so as not to overlap the focusing yoke 62, and a pair of tracking magnets 65, 65 are arranged inside thereof. . The tracking magnets 65 are configured to have opposite polarities with respect to the left and right from the center in the axial direction. For example, the tracking magnet 65 is configured such that the S pole 65a,
The N pole 65b is provided.

The lens holder 70 is formed in a substantially columnar shape, and is rotatable about a support shaft 61.
In the lens holder 70, a pair of tracking coils 71 is disposed on the outer peripheral surface that is symmetrical with respect to the rotation axis. Therefore, the lens holder 70 is adapted to exert the same rotational driving force, and can smoothly rotate. The lens holder 70 is provided with a focusing coil 72 formed in a concentric cylindrical shape relatively close to the peripheral surface of the support shaft 61, separately from the tracking coil 71. This focusing coil 72
A wire made of a conductor is wound into a small diameter in the horizontal direction, and formed as a whole with a small diameter. Correspondingly, the 2-axis base 60
Is provided with a focus yoke 62 and a focus magnet 63 close to the support shaft 61. Therefore, the focusing coil 72 can be configured to be small in size as a whole, and can increase the effective conductor length.

The lens holder 70 is provided with an objective lens 13 whose optical axis is held parallel to the support shaft 61 at a position at a predetermined distance from the rotation axis. Therefore, although the objective lens 13 will be described later, the tracking magnet 6
5, driven in the tracking direction by the magnetic action from the tracking coil 71, and driven in the focusing direction by the magnetic action from the focusing magnet 63 and the focusing coil 72. In other words, the objective lens 13 is driven by a tracking magnet 65, a tracking coil 71, a focusing magnet 63, and a focusing coil 72, which are two-axis actuators.

When a control current is passed from the optical pickup control circuit 50 to the tracking control coil 71, the optical pickup 10 moves the lens holder 70 to the support shaft 6.
1, the objective lens 13 is moved in a tracking direction, which is a substantially tangential direction, to perform tracking. The optical pickup 10 includes an optical pickup control circuit 50
When a control current flows from the optical disc, the lens holder 70 is swung up and down to focus the beam on the predetermined track of the signal recording surface of the optical disc through the objective lens 13 to perform focusing.

The error signal generation circuit 20 generates a tracking error (TE) based on the output signal of the photodiode 14 by, for example, a three-spot method or a phase comparison method.
Signal and a focus error (FE) signal, and the TE signal and the FE signal
Supply 0.

The optical pickup 30 has the same configuration as the optical pickup 10 and has a semiconductor laser element 31 which emits a laser by utilizing the recombination light emission of a semiconductor.
And a beam splitter 3 for separating the beam from the semiconductor laser element 31 and the return light from the signal recording surface of the optical disk.
2, an objective lens 33 for imaging the beam from the beam splitter 32 on a predetermined track on the signal recording surface of the optical disk, and a photodiode 34 for outputting a signal corresponding to the return light beam transmitted through the polarization beam splitter 32
And a lens holder 35 that supports the objective lens 33, and reads a recording signal from the upper side of the optical disk.

The optical pickup 30 has a configuration similar to that of the optical pickup 10 described above. When a control current is supplied from the optical pickup control circuit 50 to the tracking control coil 81, the lens holder swings around the support shaft. The objective lens 33 is moved in the tracking direction, which is a substantially tangential direction, to perform tracking. Further, when a control current is passed from the optical pickup control circuit 50 to the focus control coil 82, the optical pickup 30 swings the lens holder up and down,
Focusing is performed by irradiating a beam onto a predetermined track on the signal recording surface of the optical disc via the objective lens 33.

The error signal generation circuit 40 generates a TE signal and an FE signal based on the output signal of the photodiode 34 by, for example, a three-spot method or a phase comparison method.
These TE signal and FE signal are supplied to the optical pickup control circuit 50.

The optical pickup control circuit 50 includes switches 51, 53, 54 and 56 for switching the optical pickup 10 or the optical pickup 30 to be controlled, a tracking control driver 52 and a focus control driver 55 which are two-axis drivers. And a controller 57 for controlling switching of the switch 51 and the like.

The switch 51 is connected to the error signal generation circuit 20
Alternatively, a TE signal from the error signal generation circuit 40 is supplied, and the TE signal is supplied to the tracking control driver 52. Tracking control driver 5
2 generates a control current based on the supplied TE signal, and flows the control current to the tracking coil 71 or the tracking coil 81 via the switch 53 to generate a magnetic field. Therefore, for example, the optical pickup 10
The above-mentioned tracking can be performed by the action of the magnetic field generated in the tracking coil 71 and the magnetic field generated by the tracking magnet 65.

On the other hand, the switch 54 is supplied with an FE signal from the error signal generation circuit 20 or the error signal generation circuit 40, and supplies this FE signal to the focus control driver 55. The focus control driver 55 generates a control current based on the supplied FE signal, and causes the control current to flow to the focusing coil 72 or the focusing coil 82 via the switch 56 to generate a magnetic field. Therefore, for example, the optical pickup 10 can perform the above-described focusing by the action of the magnetic field generated in the focusing coil 72 and the magnetic field of the focusing magnet 63.

The controller 57 obtains a read signal of the optical disk from, for example, the photodiodes 14 and 34, and obtains a first type of optical disk (normal optical disk,
For example, it is determined whether the optical disk is a second type optical disk (high-density optical disk) or a second type optical disk (high-density optical disk). I do. In addition,
The controller 57 includes, for example, the photodiodes 14 and 3
According to the read result of the recording signal of No. 4, a detection result based on the difference in the amount of light reflection due to the difference in the substrate thickness of the set optical disc is obtained, and the switching of the switches 51, 53, 54, 56 is controlled. Good.

As shown in FIG. 4, the optical pickup 10 is provided with wiring for supplying a tracking control signal and a focus control signal, and the optical pickup 30 is similarly supplied with the tracking control signal and the focus control signal. Wiring is provided. The relay wire bundles 91 and 92 in which these wires are bundled are connected via switches 53 and 56. That is, the tracking coil 71 and the tracking coil 81 are connected in parallel via the switch 53, and the focusing coil 72 and the focusing coil 82 are connected in parallel via the switch 56.

In the optical disk reproducing apparatus 1 configured as described above, for example, when the optical pickup 10 reads data recorded on the optical disk, the controller 57 sets the switches 51, 53, 54, 56 to the terminals a. The setting is performed so that the reading light is emitted from the semiconductor laser element 11 while the reading light is not emitted to the semiconductor laser element 31. Then, the semiconductor laser device 1
The reading light from 1 is reflected by the optical disk 80 and enters the photodiode 14. Error signal generation circuit 20
Supplies the TE signal generated based on the output signal of the photodiode 14 to the tracking control driver 52 via the switch 51, and supplies the FE signal to the focus control driver 55 via the switch 54.

The tracking control driver 52 uses the T
Based on the E signal, the lens holder 70 is driven via the tracking coil 71, and the reading light collected by the objective lens 13 is scanned on the recording track of the optical disk. Further, the focus control driver 55 uses the FE
The lens holder 70 is driven via the focusing coil 72 based on the signal. Accordingly, even if the height of the recording surface thereof changes due to the inclination of the optical disk or the like, the focus control driver 55 allows the semiconductor laser device 11
Can be brought into a state where it is converged on the recording surface by the objective lens 13.

Next, when data is read from the optical disk by the optical pickup 30, the controller 57
Sets the switches 51, 53, 54 and 56 to the terminal b so that the semiconductor laser element 31 emits the reading light,
Control is performed so that the reading light is not emitted to the semiconductor laser element 11. Then, the reading light from the semiconductor laser element 31 is reflected by the optical disk and
Incident on. The error signal generation circuit 40 supplies the TE signal generated based on the output signal of the photodiode 34 to the tracking control driver 52 via the switch 51 and supplies the FE signal to the focus control driver 55 via the switch 54. .

The tracking control driver 52 drives the lens holder 35 via the tracking coil 81 based on the TE signal, and scans the reading light collected by the objective lens 33 on the recording track of the optical disk. The focus control driver 55 drives the lens holder 35 via the focusing coil 82 based on the FE signal. This allows the focus control driver 55 to keep the reading light from the semiconductor laser element 31 focused on the recording surface by the objective lens 33 even if the height of the recording surface changes due to the inclination of the optical disk or the like. Can be.

That is, the optical disk reproducing apparatus 1 selects an optical pickup to be controlled by the controller 57, and the tracking control driver 52 and the focus control driver 55 control tracking and focusing for the selected optical pickup, thereby An optical pickup having two objective lenses can be controlled by a biaxial driver. In other words, in the optical disc reproducing apparatus, the optical pickup 10 or the optical pickup 30 can be controlled only by the two-axis driver, that is, the tracking control driver 52 and the focus control driver 55. Accordingly, the optical disc reproducing apparatus 1 does not need to include the biaxial driver and the relay bundle in each of the optical pickups 10 and 40, so that the production cost can be reduced, and the area occupied by the substrate in the apparatus can be reduced. Can be reduced in size.

Next, an optical disc reproducing apparatus according to a second embodiment will be described. Note that the same circuits and the like as those of the optical disc reproducing apparatus 1 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

An optical disk reproducing apparatus 1a according to the second embodiment performs, for example, as shown in FIG. 5, an optical pickup 10a for reading data from the lower side of an optical disk, and generates an error signal from the read data. It includes an error generation circuit 20a and an optical pickup control circuit 50a that controls the optical pickup 10a based on an error signal from the error generation circuit 20a.

The optical pickup 10a includes a semiconductor laser device 11, a polarizing beam splitter 12, and an objective lens 1.
3, 33, photodiode 14, and objective lens 1
A lens holder 70a for supporting the lens holders 3 and 33.

As shown in FIGS. 6 and 7, the optical pickup 10a has a biaxial base 60 on which a support shaft 61 extending perpendicular to the signal recording surface of the optical disk is mounted, and an axially movable and around the axis. And a substantially circular lens holder 70a rotatably supported by the lens holder 70a.

The biaxial base 60 has a pair of arc-shaped focusing yokes 62 opposed to each other about a support shaft 61.
Are disposed, and a pair of focusing magnets 63 are disposed inside thereof. The biaxial base 60 has
A pair of arc-shaped tracking yokes 64 facing each other around the support shaft 61 are arranged so as not to overlap the focusing yoke 62, and a pair of tracking magnets 65 are arranged inside each of them. These tracking magnets 65 are configured to have opposite polarities from the center in the axial direction with respect to the left and right. For example, the tracking magnet 65 has an S pole 65a and an N pole 65b clockwise with respect to the support shaft 61.
It is arranged to be.

The lens holder 70a is formed in a substantially columnar shape, and rotates around the support shaft 61.
In the lens holder 70a, a pair of tracking coils 71, 71 are arranged on the outer peripheral surface that is symmetrical with respect to the rotation axis. Therefore, the lens holder 70a is adapted to exert the same rotational driving force, and can smoothly rotate. The lens holder 70a is provided with focusing coils 72 and 82 formed concentrically and cylindrically relatively close to the peripheral surface of the support shaft 61, separately from the tracking coils 71 and 81. . The focusing coils 72 and 82 are formed by winding a wire made of a conductor into a small diameter in the horizontal direction and forming a small diameter as a whole. Correspondingly, in the two-axis base 60, the focusing yoke 6
2 and the focusing magnet 63 are also provided near the support shaft 61. Therefore, the focusing coil 7
2 and 82 can be made small as a whole, and can increase the effective conductor length. The lens holder 70 has two objective lenses 13, 3 whose optical axes are held parallel to the support axis at a predetermined distance from the rotation axis and at different angular positions.
3 are provided.

Further, the lens holder 70a is adjacent to both sides of the tracking coil 71 in the circumferential direction, and is a magnetic member, for example, an iron piece extending in the axial direction (direction along the magnetization boundary of the tracking magnet 65). 7
5, 76 are provided.

Since the two-axis actuator drives the two objective lenses 13 and 33 based on the control of the two-axis driver, the iron pieces 75 and 76 correspond to the center positions of the respective objective lenses. There are two sets.

One of the iron pieces 75 and 76 is magnetically attracted by a magnetic flux extending from one of the two poles 65a and 65b of the tracking magnet 65 to the other. Therefore,
The iron piece 75 or the iron piece 76 faces a boundary 65c between the two poles 65a and 65b of the tracking magnet 65.

As shown in FIG. 5, the relay wire bundle 92a
Is branched from the middle of the trunk bundle 91a and connected.
Tracking coil 71 and tracking coil 8
1. The focusing coil 72 and the focusing coil 82 are connected in parallel.

The error generating circuit 20a obtains the read signal of the optical disk from the photodiode 14, for example, and selects the first type of optical disk or the second type of optical disk. The tracking coils 71 and 8 via the tracking control driver 55 so that the optimal objective lens is selected.
1 is supplied with a control current. The error generation circuit 20a obtains a detection result based on a difference in the amount of light reflection due to a difference in substrate thickness of the set optical disc, for example, based on a read result of the recording signal of the photodiode 14, and outputs the detection result via the tracking control driver 55. Alternatively, a control current may flow through the tracking coils 71 and 81.

The optical pickup control circuit 50a includes a tracking control driver 52, which is a biaxial driver, which is a biaxial driver, and a focus control driver 55, and controls a biaxial actuator.

In the optical disk reproducing apparatus 1a configured as described above, when a control current is passed from the optical pickup control circuit 50a to the tracking control coil 71, the optical pickup 10a swings the lens holder 70a around the support shaft 61. The objective lens 13 is moved in the tracking direction, which is a substantially tangential direction, to perform tracking. Also, the optical pickup 10a
When a control current flows from the optical pickup control circuit 50 to the focus control coil 72, the lens holder 70
Focusing is performed by oscillating a in the vertical direction so that the beam is irradiated onto a predetermined track on the signal recording surface of the optical disk via the objective lens 13.

Here, for example, when the objective lens 13 is inserted in the optical path, as shown in FIG.
Opposes a boundary 65c between the two magnetic poles 65a and 65b of the opposing tracking magnet 65. The lens holder 70a is located at the first midpoint position, and is held at the first midpoint position by the flow of magnetic flux as indicated by the arrow. Accordingly, when a drive current is applied to the tracking coil 71, the optical pickup 10a swings the lens holder 70a around the support shaft 61 with reference to the first midpoint position, and substantially moves the objective lens 13 Tracking is performed by moving in the tracking direction which is a tangential direction. The optical pickup 10a includes a tracking coil 7
When a drive current flows through the objective lens 2, the objective lens 13 is moved in the focusing direction by moving the objective lens 13 in the axial direction by sliding the lens holder.

When a reverse current is applied to the tracking coil 71, as shown in FIG.
5 and repels the tracking coil 71
Move to face the magnetic pole 65b. This allows
The opposite iron piece 75 faces the boundary 65c between the magnetic poles 65a and 65b of the tracking magnet 65, the lens holder 70a is moved to the second midpoint position, and the objective lens 3 is moved.
3 will be inserted into the optical path. Then, the optical pickup 10a swings the lens holder 70a around the support shaft 61 with reference to the second midpoint position, moves the objective lens 13 in a tracking direction that is substantially tangential, and performs tracking. I do. Optical pickup 1
When a driving current flows through the tracking coil 72, the objective lens 13 moves in the focusing direction by moving the objective lens 13 in the axial direction by sliding the lens holder.

When a reverse current is further applied to the tracking coil 71 while the lens holder 70a is held at the second midpoint position, the lens holder 70a is again moved to the first midpoint position. It is designed to be moved to a position.

That is, when performing tracking and focusing by driving the objective lenses 13 and 33 of the optical pickup 10a, the optical disk reproducing apparatus 1a controls the tracking control driver 52 and the focus control driver 55 to control the tracking coils 71 and 33. 81, a drive current can be passed through the tracking coils 72 and 82.
In other words, the optical disc reproducing device 1a requires a small number of biaxial drivers and a bundle of relay wires for connecting the two-axis drivers to a circuit or the like, thereby reducing the production cost and simplifying the circuit configuration to reduce the size of the device. be able to.

[0056]

As described above in detail, according to the optical disk reproducing apparatus of the present invention, the circuit configuration is provided by providing a common two-axis driver for controlling two two-axis actuators to perform tracking and focusing. Can be simplified to reduce the occupied area of the base, thereby reducing production costs.

According to the optical disk reproducing apparatus of the present invention, one of the two pickups provided so as to face each other with respect to the recording medium is selected, and the two-axes of the optical pickup selected by the two-axis driver are selected. By controlling the actuator, it is not necessary to provide a two-axis driver for each of the two optical pickups, and the number of relay lines between the circuits can be reduced, thereby suppressing an increase in production cost due to an increase in the occupied area of the board. can do.

According to the optical disk reproducing apparatus of the present invention, the biaxial actuator corresponding to the objective lens selected by the selecting means is controlled so that the objective lens selected by the selecting means is driven at the tracking position. This simplifies the circuit configuration and reduces the number of relay bundles for driving the objective lens.
The production cost can be suppressed and the size of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc reproducing device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of an optical pickup of the optical disk reproducing device.

FIG. 3 is a perspective view of the optical pickup.

FIG. 4 is a diagram of a relay wire bundle wired to two optical pickups of the optical disc reproducing device.

FIG. 5 is a block diagram showing a configuration of an optical disc reproducing device according to a second embodiment of the present invention.

FIG. 6 is an exploded perspective view of an optical pickup of the optical disk reproducing device.

FIG. 7 is a perspective view of an optical pickup of the optical disk reproducing device.

FIG. 8 is a plan view of a main part of the optical pickup.

FIG. 9 is a plan view of a main part of the optical pickup.

[Explanation of symbols]

10, 30 Optical pickup, 51, 53, 54, 56
Switch, 52 tracking control driver, 55
Focus control driver

Claims (3)

[Claims] 1. A method for driving two objective lenses, respectively.
An optical disc reproducing apparatus comprising: two biaxial actuators; and a biaxial driver that controls the two biaxial actuators to perform tracking and focusing. 2. An optical pickup provided with the two biaxial actuators for driving the two objective lenses arranged to face each other via a recording medium, and one of the two biaxial actuators Selecting means for selecting the selected one of the two axes, wherein the two-axis driver selects the two selected by the selecting means.
2. A shaft actuator is controlled.
An optical disc playback device according to claim 1. 3. An optical pickup in which the two objective lenses are arranged on one side with respect to a recording medium, and the two objective lenses are respectively driven by the two biaxial actuators; and one of the two objective lenses is Selecting means for selecting, the two-axis driver corresponding to the objective lens selected by the selecting means so as to drive the objective lens selected by the selecting means at a tracking position.
2. A shaft actuator is controlled.
An optical disc playback device according to claim 1.