JP2002358676A - Optical pickup and optical disk device provided with the same - Google Patents

Abstract

(57) [Summary] [Problem] Even when a high NA is achieved by using a plurality of lens elements as a condenser lens means, it is possible to cope with dynamic fluctuations in the thickness and tilt of an optical disc, and a plurality of lenses are used even during tracking. An optical pickup that does not cause optical axis misalignment between them is realized. SOLUTION: In an optical pickup 5, a first lens 16 as a condensing lens means for condensing a light beam 9 on the optical disc 1 is provided on a slider 10 which is floated on the optical disc 1 via an air bearing. The second lens 17 is mounted. The distance between the first lens 16 and the second lens 17 is controlled by the piezoelectric element layer 15 provided on the slider 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical disk apparatus for performing at least one of recording, reproducing, and erasing of information on an optical disk, and an optical pickup mounted on the apparatus.

[0002]

2. Description of the Related Art In recent years, with the development of optical discs capable of reproducing, recording and erasing information,
Optical disks are becoming increasingly popular for consumer use and data storage. At present, research to satisfy further demands for higher density and higher capacity is being actively pursued.

[0003] In order to increase the density and capacity of an optical disk, information can be reproduced and recorded with a smaller mark (recording bit) for substantiating the recorded information on the optical disk. For that purpose, it is necessary to reduce the spot diameter of the light beam applied to the optical disk.

[0004] In principle, the spot diameter of a light beam is λ / N
It is proportional to A. (Λ: wavelength of light, NA: numerical aperture of objective lens)
By reducing the wavelength of light used for recording and reproduction and increasing the numerical aperture NA of the objective lens, it is possible to reduce the diameter of the beam spot.

However, when the wavelength of light is shortened or the numerical aperture NA of the objective lens is increased, a large wavefront aberration occurs due to the inclination of the disk substrate, and the light beam cannot be accurately focused. I will. In order to compensate for this, conventionally, the thickness of the disk substrate has been reduced.

For example, in the case of a CD-ROM, the numerical aperture NA of the objective lens is 0.45, the wavelength of light is 780 nm, and the thickness of the substrate is 1.2 mm. Is 0.6 and the wavelength of light is 655 nm.
In the D-ROM, the thickness of the substrate is set to 0.6 mm to increase the recording capacity and increase the allowable amount with respect to the inclination of the disk substrate.

However, when the disk substrate is further thinned, the inclination (tilt) of the substrate due to the surface deflection of the disk substrate itself is increased due to a decrease in rigidity, which has an adverse effect. Therefore, there is a limit to shortening the wavelength of light and increasing the numerical aperture NA of the objective lens.

An optical disk device disclosed in Japanese Patent Application Laid-Open No. 2000-36124, for example, has been proposed to solve such a problem.

[0009] The optical disk device disclosed in the publication has a structure shown in FIG.
As shown in FIG. 3, a two-dimensional actuator 100 drivable in a focus direction 108 and a track direction 109, a first lens 102 held by a lens holder 101 fixed to the two-dimensional actuator 100, and a lens holder 101 Supported by the leaf spring 103, and
A slider 105 which is levitated on an rotating optical disk 104 via an air bearing (air film);
A second lens 106 held by the slider 105, and irradiating the laser beam 107 with the first lens 10
With the objective lens system including the second and second lenses 106, it is possible to converge and irradiate the signal recording surface of the optical disc 1 with light.

Since the slider 105 is supported by the leaf spring 103, the slider 105 has a predetermined spring constant in the focus direction 108 and is supported by the lens holder 101 so as to have a degree of freedom with respect to the tilt of the optical disk 104. Have been.

In such a configuration, the slider 10
5 is floated by the air bearing, the inclination of the slider 105 follows the inclination of the optical disk 104, and the wavefront aberration can be suppressed, and the first lens 102 is driven by the two-dimensional actuator 100 in the focus direction 108, so that the optical disk 104 It is possible to dynamically control the load applied to the optical disk 104 by the slider 105 even when the disk surface is shaken in the thickness direction due to uneven thickness or curvature of the disk or dynamic fluctuation of tilt. It is said that it is possible to imitate the surface of the optical disk 104 well, suppress wavefront aberration, and realize a high NA.

[0012]

However, in the configuration described in Japanese Patent Application Laid-Open No. 2000-36124, the first lens 102 and the second lens 1
There is a problem that the optical axis shift of 06 easily occurs, and the shape of the focused spot is deformed from a circular shape.

That is, in the above configuration, the first lens 102 fixed to the lens holder 101 and the slider 105
The second lens 106 is fixed via a leaf spring 103. The leaf spring 103 has a predetermined spring constant not only in the focus direction 108 but also in the track direction 109. Therefore, when the lens holder 101 is driven in the track direction 109 for tracking, the first lens 102 and the second lens 106 are displaced in the track direction 109, and the first lens 102 and the second lens
An optical axis deviation from the lens 106 occurs. When the optical axis shift occurs, the converging spot shape is deformed from a circular shape due to the aberration caused by the optical axis shift, and it becomes difficult to maintain good recording / reproducing characteristics.

[0014]

In order to solve the above-mentioned problems, an optical pickup according to the present invention comprises a plurality of lenses for condensing a light beam on an optical disk on a slider floating above the surface of the optical disk by rotation of the optical disk. And a lens interval between the plurality of lenses is controlled by a piezoelectric element layer mounted on the slider.

The slider is arranged so as to be in contact with the surface of the optical disk while the optical disk is stopped, and is separated by an air bearing formed on the surface of the optical disk when the optical disk is rotated. And
Although the expression “floating” is used, it is not limited to the one floating upward.

According to this, since the condenser lens means is mounted on the slider that floats above the optical disk surface, the slider follows the optical disk surface, so that the wavefront aberration can be suppressed.

Since the lens spacing of the plurality of lenses constituting the condenser lens means is controlled by the piezoelectric element layer mounted on the slider together with the condenser lens means, focusing can be easily performed and the light beam can be transferred to the optical disk. Can be collected. Therefore, the piezoelectric element can be used for dynamic fluctuations that cannot be followed only by the slider following the surface of the optical disk via the air bearing, such as fluctuations in the thickness direction of the optical disk due to uneven thickness or curvature of the optical disk, or tilt. It can be easily handled by driving the layer to perform focusing.

Further, in this configuration, since all of the plurality of lenses constituting the condenser lens means are mounted on the slider, even if the condenser lens means is moved in the track direction (horizontal direction) during tracking, the condenser lens can be moved. Unlike the configuration in which the plurality of lenses constituting the means are separately mounted on the slider and the member other than the slider, each lens does not shift in the track direction. Therefore, even if a high NA is achieved by using a plurality of lenses constituting the condensing lens means, no optical axis shift occurs between the plurality of lenses, and the condensed spot shape on the optical disc can be made a good circular shape.

As a result, it is possible to maintain good recording / reproducing characteristics even if a condensing lens means composed of a plurality of lenses is used in order to achieve a higher NA. Can be achieved.

In order to solve the above-mentioned problems, an optical pickup according to the present invention, in the optical pickup having the above-described configuration, holds the slider on a slider holding member via a first elastic member for urging the slider toward the optical disk. Wherein the first elastic member is made of a conductive material,
Power is supplied to the piezoelectric element layer via the first elastic member.

In such a configuration in which the slider is urged toward the optical disk by the first elastic member, the state of the air bearing (air film) formed between the slider and the optical disk surface when the optical disk rotates. Is stabilized, the slider follows the optical disk surface more stably, and the wavefront aberration can be suppressed more effectively.

When a conductive wire extending to the piezoelectric element layer mounted on the slider is provided, the conductive wire acts as a spring due to its own rigidity, and may hinder stable floating of the slider. Therefore, in the above configuration, the first elastic member is formed from a conductive material, and power is supplied to the piezoelectric element layer via the first elastic member. Accordingly, as compared with a configuration in which a conductive wire extending to the piezoelectric element layer is separately formed, the cost can be reduced, and the stable floating of the slider is not hindered by the conductive wire extending to the piezoelectric element layer. Therefore, more stable focusing is realized.

In order to solve the above-mentioned problems, an optical pickup according to the present invention, in the optical pickup having the above-described structure, wherein a slider holding member for holding the slider is a second member for supporting the slider holding member so as to swing in the track direction. The second elastic member is made of a conductive material, and is driven by the actuator held by the slider holder in the track direction. Power is supplied to the actuator via a member.

In such a configuration, the slider holding member is swingably held in the track direction by the carriage via the second elastic member, and is driven in the track direction by the actuator held by the slider holding member. In addition, even if the optical disk has eccentricity, tracking can be performed by performing tracking.

In the case where a lead extending to the actuator held by the slider holding member is provided, the lead acts as a spring due to its own rigidity, and is slidably held by the second elastic member. It may hinder the movement of the holder. Therefore, in the above configuration, the second elastic member is formed of a conductive material, and power is supplied to the actuator provided on the slider holder via the second elastic member. As a result, the cost can be reduced as compared with a configuration in which a lead wire extending to the actuator is separately formed, and the swing of the slider holder in the track direction is prevented by the lead wire extending to the actuator. , More stable tracking is realized.

In order to solve the above-mentioned problems, an optical pickup according to the present invention, in the optical pickup having the above-mentioned structure, wherein the slider is held on a slider holder via a first elastic member for urging the slider toward the optical disk. The slider holding member is held by the carriage via a second elastic member that supports the slider holding member so as to be swingable in the track direction, and the slider is held by the actuator held by the slider holding member. The first elastic member and the second elastic member are both made of a conductive material, and the first elastic member and the second elastic member
Power is supplied to the piezoelectric element layer via the elastic member, and power is supplied to the actuator via the second elastic member.

According to this, as described above, the state of the air bearing is stabilized, and the wavefront aberration can be more effectively suppressed. It will be able to follow. In addition to this, the power supply to the piezoelectric element
Since the power supply to the actuator is performed via the second elastic member while the power is supplied via the second elastic member and the second elastic member, stable focusing and tracking are realized.

In order to solve the above problems, the optical pickup of the present invention is characterized in that, in the optical pickup having the above-described configuration, a magnetic field applying means is mounted on the slider.

When a magneto-optical recording material is used as a recording material in an optical disk (a magneto-optical disk), it is necessary to apply a magnetic field to the optical disk. Is mounted, the structure of the optical disk device on which the optical pickup is mounted can be further simplified as compared with a configuration in which a magnetic head such as a slider on which a magnetic field applying unit is mounted is separately provided.

In order to solve the above-mentioned problems, an optical pickup according to the present invention, in the above-described optical pickup, holds the slider on a slider holder via a first elastic member that urges the slider toward the optical disk. Wherein the first elastic member is made of a conductive material,
Power is supplied to the magnetic field applying means via the first elastic member.

As described above, by adopting a configuration in which the slider is urged toward the optical disk by the first elastic member, the slider follows the optical disk surface more stably and suppresses wavefront aberration more effectively. It becomes possible.

Further, in the above configuration, the first elastic member is formed of a conductive material, and power is supplied to the magnetic field applying means via the first elastic member. As in the case of supplying power to the piezoelectric element layer, the cost can be reduced as compared with a configuration in which a conductor extending to the magnetic field applying means is separately formed. As a result, stable floating of the slider is not hindered, so that more stable focusing is realized.

In order to solve the above-mentioned problems, an optical pickup according to the present invention, in the optical pickup having the above-described configuration, wherein a slider holding member for holding the slider is a second member for supporting the slider holding member so as to swing in the track direction. The second elastic member is made of a conductive material, and power is supplied to the magnetic field applying means via the second elastic member. It is characterized by.

As described above, in the configuration in which the slider holding body is held by the carriage via the second elastic member so as to be swingable in the track direction, an eccentricity is provided by providing an actuator and driving the slider in the track direction. Even an optical disc can be followed by performing tracking.

Further, in the above configuration, the second elastic member is formed of a conductive material, and power is supplied to the magnetic field applying means provided on the slider holder via the second elastic member. Therefore, as in the case of supplying power to the actuator held by the slider holding member, the cost can be reduced as compared with the configuration in which a conductive wire extending to the magnetic field applying means is separately formed. Since the swing of the slider holding body in the track direction is not hindered by the above-mentioned conducting wire extending to the application means, more stable tracking is realized.

According to another aspect of the present invention, there is provided an optical pickup having the above-mentioned configuration, wherein the slider is held by a slider holder via a first elastic member for urging the slider toward the optical disk. And the slider holding member is held by a carriage via a second elastic member that supports the slider holding member so as to be swingable in the track direction. The member and the second elastic member are both made of a conductive material, and power is supplied to the magnetic field applying means via the first elastic member and the second elastic member.

According to this, as described above, the state of the air bearing is stabilized, and the wavefront aberration can be more effectively suppressed. In addition, the actuator is provided and driven in the track direction. It is possible to follow even an optical disk having eccentricity by performing tracking, and since power is supplied to the magnetic field applying means via the first elastic member and the second elastic member, stable focusing and tracking are realized. Is done.

Further, an optical disk device according to the present invention is provided with the above-described optical pickup according to the present invention in order to solve the above problems.

As a result, it is possible to provide an optical disk device capable of realizing high-density recording / reproduction with a high NA. The optical disk device of the present invention includes not only a device exclusively for reading an optical disk, but also a magneto-optical disk device capable of reading and writing on a magneto-optical disk by a magnetic field modulation method or a light pulse modulation method.

The optical pickup according to the present invention has a slider which floats on the optical disk via an air bearing, and a first lens and a second lens which are held by the slider for condensing a light beam on the optical disk. And a piezoelectric element layer for controlling the distance between the first lens and the second lens may be provided on the slider.

According to this, the first lens and the second lens are fixed to the slider having the piezoelectric element layer, and the distance between the first lens and the second lens is controlled by driving the piezoelectric element layer. By doing so, it becomes possible to easily perform the focusing drive. Further, since the horizontal positional relationship between the first lens and the second lens is fixed, even when the tracking drive is performed, the optical axis shift between the first lens and the second lens does not occur, and the condensing spot is formed. The shape becomes a good circular shape, and good recording / reproducing characteristics can be maintained.

Also, the optical pickup of the present invention has a slider which is levitated on an optical disk via an air bearing, and a first lens and a second lens which are held by the slider for condensing a light beam on the optical disk. And a piezoelectric element layer for controlling a distance between the first lens and the second lens is provided on the slider, and the slider is provided with a first spring with respect to the slider holder. And the slider is pressed against the optical disc.

According to this, when the slider is pressed against the optical disk, the state of the air bearing is stabilized, the slider follows the optical disk surface, and the wavefront aberration can be suppressed.

Further, the optical pickup of the present invention has a slider which is levitated on an optical disk via an air bearing, and a first lens and a second lens which are held by the slider for condensing a light beam on the optical disk. And a piezoelectric element layer for controlling a distance between the first lens and the second lens is provided on the slider, and the slider is provided with a first spring with respect to the slider holder. The slider is pressed against the optical disk, and the slider holder is fixed to the optical pickup carriage via a second spring, and tracking is performed by an actuator that can be driven in the track direction. The operation may be performed.

According to this, the first lens of the present invention and the second lens
The tracking drive of the slider having the lens and the slider holder supporting the slider can be realized, and the slider according to the optical pickup of the present invention can be adopted also in the eccentric optical disk.

Also, the optical pickup of the present invention has a slider which is levitated on an optical disk via an air bearing, and a first lens and a second lens which are held by the slider for condensing a light beam on the optical disk. And a slider provided with a piezoelectric element layer for controlling a distance between the first lens and the second lens, and an air core around the second lens fixed to the slider. It may be characterized in that a coil is provided.

According to this, a magnetic field can be applied to the optical disk by the air-core coil, and the slider according to the optical pickup of the present invention is employed in a magneto-optical disk using a magneto-optical recording material as a recording medium. It is possible to do.

Further, the optical pickup of the present invention has a slider which is levitated on an optical disk via an air bearing, and a first lens and a second lens which are held by the slider for condensing a light beam on the optical disk. And a piezoelectric element layer for controlling a distance between the first lens and the second lens is provided on the slider, and the slider is provided with a first spring with respect to the slider holder. The slider is pressed against the optical disk, and a first spring supporting the slider is formed of a conductive material, and power is supplied to the piezoelectric element layer through the first spring. May be performed.

According to this, it is not necessary to separately provide a conducting wire or the like for supplying power to the piezoelectric element layer provided on the slider, so that the cost can be reduced and the pressing force of the first spring against the optical disk can be reduced. Stable and stable focusing is realized.

Further, the optical pickup of the present invention has a slider which is floated on an optical disk via an air bearing, and a first lens and a second lens which are held by the slider for condensing a light beam on the optical disk. And a piezoelectric element layer for controlling a distance between the first lens and the second lens is provided on the slider, and the slider is provided with a first spring with respect to the slider holder. The slider is pressed against the optical disk, and the slider holder is fixed to the optical pickup carriage via a second spring, and tracking is performed by an actuator that can be driven in the track direction. The second spring supporting the slider holder is formed of a conductive material.
Power may be supplied to a coil constituting a tracking actuator fixed to the slider holder via a spring.

According to this, it is not necessary to separately provide a conducting wire or the like for supplying electric power to the coil constituting the tracking actuator fixed to the slider holder.
The cost reduction is realized, and the support state of the slider holder by the second spring is stabilized, so that stable tracking can be realized.

Further, the optical pickup of the present invention has a slider which is floated on an optical disk via an air bearing, and a first lens and a second lens which are held by the slider for condensing a light beam on the optical disk. And a slider provided with a piezoelectric element layer for controlling a distance between the first lens and the second lens, and an air core around the second lens fixed to the slider. A coil is provided, and the first spring supporting the slider, the second spring supporting the slider holder, or both of them are formed of a conductive material, and the first spring and the second spring are formed. The power may be supplied to the air-core coil via the power supply.

According to this, it is not necessary to separately provide a conducting wire or the like for supplying electric power to the air-core coil provided on the slider, and the cost can be reduced. Then, while the pressing force on the optical disk by the first spring is stabilized,
The support state of the slider holder by the second spring is stabilized, and stable focusing and tracking can be realized.

[0054]

[Embodiment 1] One embodiment of the present invention will be described with reference to FIGS.
It is as follows.

FIG. 5 shows an optical pickup 5 according to this embodiment.
1 shows a schematic configuration of an optical disk device on which is mounted. here,
1 is an optical disk, 2 is a center hub, and 3 is a spindle. The optical disc 1 is fixed to a spindle 3 via a center hub 2 and is driven to rotate. The optical pickup 5 is driven to access the optical disc 1 in the radial direction by a linear motor or a swing arm (not shown).

FIG. 1 is an enlarged sectional view of the optical pickup 5 in FIG. FIG. 2 is a plan view of the optical pickup 5.

The optical disk 1 includes an optical disk substrate 6, an optical recording medium 7, and a protective coat 8. The light beam 9 emitted from the optical pickup 5 is transmitted to the first lens 16
The light passes through an objective lens system composed of an optical recording medium 7 and a second lens 17, and is condensed and irradiated on the optical recording medium 7 to record, erase, and reproduce information.

As the optical disk substrate 6, a resin substrate such as polycarbonate can be used, and a guide groove (not shown) for tracking is formed on the light beam converging surface of the optical disk substrate 6. Examples of the optical recording medium 7 include phase change recording materials such as GeSbTe and InAgSbTe, magneto-optical recording materials such as TbFeCo, and TbFe.
A super-resolution magneto-optical recording material in which a plurality of layers of Co and GdFeCo or the like are stacked, or a write-once recording material using a dye-based organic material can be used.

The protective coat 8 is provided for the purpose of protecting the optical recording medium 7 from being damaged when a slider 10 described later comes into contact with the optical disc 1, and is at least a material that transmits light. is necessary. As the protective coat 8, for example, a transparent resin layer such as an ultraviolet curable resin layer or a layer to which a transparent sheet is adhered can be used. Also, a transparent dielectric such as SiN or AlN can be used.

The optical disc 1 may be a read-only optical disc in which concave and convex pits are formed on the optical disc substrate 6 and a reflection film is provided instead of the optical recording medium 7.

The optical pickup 5 includes a light emitting element 23 and a focusing / tracking light receiving element 2 as an optical system.
4, a light emitting / receiving element section 11 having optical elements such as a reproduction signal detecting light receiving element 25, a rising mirror 14, a first lens 16, and a second lens 17. The light emitting / receiving element unit 11 is fixedly arranged on an optical pickup carriage (carriage) 12 that is driven to access the optical disc 1 in the radial direction by a linear motor or a swing arm (not shown). The light beam 9 emitted from the light emitting / receiving element 11 is bent in the direction of the optical disc 1 by a rising mirror 14 fixedly arranged on a slider holder (slider holding body) 13, and is held by the slider 10. The light passes through the first lens 16 and the second lens 17 and is focused and irradiated on the optical recording medium 7.

The slider 10 is supported by the slider holder 13 via a pair of first springs (first elastic members) 18 composed of leaf springs. First spring 18
Has a biasing force in the direction of pushing up the slider 10 toward the optical disk 1, and the slider 10
It is pressed against the optical disk 1 by the urging forces of 8.18. With this configuration, when the slider 10 floats (separates) from the surface of the optical disk 1 with the rotation of the optical disk 1,
The thickness of the air bearing generated between the optical disk 1 and the slider 10 is stabilized, and the optical disk 1 and the slider 1
The interval with 0 is maintained at a constant interval. The slider 1
The urging means for pressing 0 toward the optical disc 1 is not limited to a spring, but may be any elastic body.

On the other hand, the slider holder 13 for supporting the slider 10 has a pair of second springs (second
Are supported by the optical pickup carriage 12 via elastic members (19, 19). Here, the slider holder 1
3 is supported (movable) in the track direction 20 (disc radial direction) with respect to the optical pickup carriage 12.

The slider holder 13 is moved in the track direction by a magnetic circuit including a pair of permanent magnets 21 fixed to the optical pickup carriage 12 and a pair of coils 22 fixed to the slider holder 13. 20 is driven. The permanent magnets 21 and the coils 22 form a tracking actuator that can be driven in the track direction 20. The slider 10, the first lens 16, and the second lens 17 are driven in the track direction 20 together with the slider holder 13. The means for swingably supporting the slider holder 13 with respect to the optical pickup carriage 12 is not limited to a spring, but may be any elastic body.

As shown in FIG. 3, which is a partially enlarged view of the optical pickup 5, the slider 10 has a configuration in which the piezoelectric element layer 15 is sandwiched between a pair of slider members 26. For the slider members 26, 26, for example, a material such as a metal plate, a glass plate, and a plastic plate having a thickness of 0.2 to 1.5 mm can be used. Piezoelectric element layer 15
Constitutes a focus actuator that can be driven in the focus direction 4 and has a thickness of 0.2 to 1.0.
mm laminated piezoelectric element, for example,
No. 20, a laminated piezoelectric actuator can be used.

In the slider 10, the first lens 1
The sixth lens 17 and the second lens 17 are attached to a through hole 27 penetrating the slider 10 so as to sandwich the piezoelectric element layer 15. Therefore, by applying a voltage to the piezoelectric element layer 15, the distance between the first lens 16 and the second lens 17 is controlled, and the variation in the thickness of the protective coat 8 and the flying height between the optical disk 1 and the slider 10 are controlled. Focusing is performed in order to correct an abnormality in the light condensing state on the optical recording medium 7 caused by a change in the height.

The through hole 27 formed in the slider 10
Are formed by forming mortar-shaped depressions on a surface of the slider 10 facing the optical disk 1 and a surface of the slider 10 facing the slider holder 13, respectively. Each of the first lens 16 and the second lens 17 is fixed with an adhesive with the slope of each mortar-shaped depression as a reference plane.

As described above, the first lens 16 and the second lens 1
7 is fixed to the slider 10 by bonding.
Both lenses are fixed in the horizontal direction (track direction), and no displacement occurs in the track direction. Therefore, at the time of tracking, the first lens 16
Even if the second lens 17 is driven, the optical axis of the first lens 16 and the second lens 17 does not deviate, and the shape of the condensed spot is maintained in a circular shape, thereby maintaining good recording / reproducing characteristics. Becomes possible.

In the optical pickup 5, the focusing and tracking servo operations are performed by the focus actuator and the tracking actuator.
This is performed by feeding back the focus error signal and the tracking error signal output from the focusing / tracking light receiving element 24 in the light emitting / receiving element 11 described above.

That is, as shown in FIG. 4, the focus error signal 28 and the tracking error signal 29 output from the focusing / tracking light-receiving element 24.
Is supplied to the control circuit 30, the control circuit 30 supplies a focus control signal to the piezoelectric element layer 15 constituting the focus actuator based on the input focus error signal 28, performs focusing, and A pair of coils 22 forming a tracking actuator based on a tracking error signal 29
(See FIG. 2) to supply a tracking control signal to perform tracking.

In the optical pickup 5 of this embodiment, the supply of the focus control signal from the control circuit 30 to the piezoelectric element layer 15 is performed by a pair of focus control leads 31 connecting the control circuit 30 and the piezoelectric element layer 15. Done through
The supply of the tracking control signal from the control circuit 30 to the coils 22 is performed by the control circuit 30 and the coils 22.
2 and a pair of lead wires 32 for tracking control connecting
Done through.

Next, the results of examining the performance of each of the focusing and tracking servos in the optical pickup 5 having the above configuration will be described.

In examining the performance, the optical disc 1
On the optical disk substrate 6 having a thickness of 1.2 mm, a film thickness of 120 n
An optical recording medium 7 consisting of an Ag reflective film having a thickness of m, a ZnS-SiO2 interference film having a thickness of 20 nm, an AgInSbTe phase-change recording film having a thickness of 15 nm, and a ZnS-SiO2 interference film having a thickness of 40 nm is sequentially laminated. A protective coat 8 made of a resin was formed with a thickness of 50 μm. On the substrate of the optical disc 1, an uneven guide track in which lands and grooves having a width of 0.25 μm are formed in a spiral shape is formed at a depth of 30 nm.

Then, the optical disk 1 is
After rotating at 3000 rpm, the optical pickup 5 is brought close to the optical disc 1 and
And the slider 10 were arranged such that the distance between them was about 10 μm.

The light emitting and receiving element 1 of the optical pickup 5
A light source in 1 is a semiconductor laser having a wavelength of 410 nm, and the first lens 16 and the second lens 17 are configured such that the effective numerical aperture NA is 1.0. The light beam spot diameter in the optimum state at
It was 0 nm.

FIG. 6 shows the variation of the focus error amount during one rotation of the optical disk. The focus error amount on the vertical axis is
This is the focus error amount on the optical recording medium 7 converted from the focus error signal 28.

As can be seen from this figure, the focus error amount is at most 0.07 μm, indicating that the focus control system of the optical pickup 5 is operating well. In general, the focus error amount is ±
If it is within 0.1 μm, it is determined that the focus control system is operating well.

FIG. 7 shows the variation of the track error amount in one rotation of the optical disk. The track error amount on the vertical axis is a track error amount with respect to the uneven track formed on the optical disk 1 converted from the track error signal 29.

As can be seen from this figure, the track error amount is at most 0.03 μm and the optical pickup 5
It can be seen that the tracking control system of FIG. In general, the track error amount is ±
If it is within 0.1 μm, it is determined that the tracking control system is operating well.

[Embodiment 2] Another embodiment of the present invention will be described below with reference to FIGS. For convenience of description, components having the same functions as those shown in the drawings of Embodiment 1 are given the same reference numerals, and descriptions thereof are omitted.

In the optical pickup 5 of the first embodiment, a pair of focus control leads 31
31 is connected, the focus control lead 31
Will act as a spring due to its own rigidity, and the focusing may be unstable. Also in FIG. 6, a local focus error is observed as indicated by an arrow, and this local focus error determines the maximum focus error amount.

Therefore, the optical pickup 5 of the present embodiment
8, a pair of first springs 18 that hold the slider 10 with respect to the slider holder 13 have conductivity with respect to the slider holder 13 and are moved in the focusing direction through these first springs 18 as shown in FIG. A focus control signal is supplied to the piezoelectric element layer 15 that constitutes a drivable focus actuator.

That is, the focus control leads 31.3
1 is connected to a conductive wire (not shown) fixed on the slider holder 13 or an electrode (not shown) made of a conductive metal formed on the slider holder 13. The conductive wires or electrodes fixed on the slider holder 13 extend to a portion where the first springs 18 are fixed to the slider holder 13. In the slider 10, a pair of conducting wires 33, each extending from a portion where the first spring 18 is fixed to the slider 10 to the piezoelectric element layer 15, is formed.

As a result, the focus control signal supplied from the control circuit 30 is applied to the focus control leads 31.3.
1. The piezoelectric element layer 15 is supplied to the piezoelectric element layer 15 via a conductive wire or an electrode fixed on the slider holder 13, first springs 18, and conductive wires 33. Here, the conductive wire 33 may be an electrode made of a conductive metal formed on the surface of the slider 10.

The optical pickup 50 of the present embodiment
Has the same configuration as that of the optical pickup 5 of the first embodiment except that the configuration of a portion for supplying a focus control signal is different, and therefore further description is omitted.

In the optical pickup 50, the slider 10 is supported only by the pair of first springs 18 fixed to the slider holder 13, so that the focus control is further stabilized.

FIG. 9 shows the result of obtaining the focus error amount in the same manner as in FIG. As can be seen from this figure, it can be confirmed that the local focus error as shown in FIG. 6 is reduced and the maximum focus error amount is reduced to 0.04 μm.

[Embodiment 3] Another embodiment according to the present invention will be described below with reference to FIGS. For convenience of explanation, the first embodiment,
Components having the same functions as the components shown in the drawings of FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

In the optical pickup 5 according to the first embodiment, since the pair of tracking control wires 32 is connected to the slider holder 13, the tracking control wires 32 have the rigidity of their own. As a result, the tracking may be unstable. Also in FIG. 7, a local track error is observed as indicated by an arrow, and this local track error determines the maximum track error amount. The same problem also occurs in the optical pickup 50 according to the second embodiment having the same tracking control lead wires 32.

Therefore, the optical pickup 5 of the present embodiment
In FIG. 1, as shown in FIG. 10, in the configuration of the optical pickup 50 according to the second embodiment, a pair of second springs 19 that support the slider holder 13 to be able to swing with respect to the optical pickup carriage 12 are electrically conductive. And a pair of coils 22 constituting a tracking actuator drivable in the track direction via the second springs 19.
-A tracking control signal is supplied to 22.

That is, in the optical pickups 5 and 50, the pair of second springs 19 and 19 are composed of a pair of parallel leaf springs arranged in parallel with each other. Since it is necessary to supply a signal to the coils 22, each leaf spring 19 is divided into two parts 19 a and 19 b, so that a total of four leaf springs are used.

[0092] The focus control conductors 31 may be a conductor (not shown) fixed on the optical pickup carriage 12 or an electrode (not shown) made of a conductive metal formed on the optical pickup carriage 12. Through
It is connected to two of the four conductive leaf springs. Then, the first spring 18.1 is connected via the leaf spring.
Reference numeral 8 extends to a portion fixed to the slider holder 13 and is connected to the above-described conductive wire or electrode on the slider holder 13.

On the other hand, the tracking control leads 32
Is a lead wire (not shown) fixed on the optical pickup carriage 12 or the optical pickup carriage 12
It is connected to the remaining two leaf springs of the four leaf springs having conductivity through an electrode (not shown) made of a conductive metal formed thereon. And a lead wire (not shown) fixed on the slider holder 13 from the leaf spring, or
A tracking control signal is supplied to the coils 22 via electrodes (not shown) made of a conductive metal formed on the slider holder 13.

The optical pickup 51 has the same configuration as that of the optical pickup 5 except that the configuration for supplying the focus control signal and the configuration for supplying the tracking control signal are different, so that further description is omitted. .

In such an optical pickup 51, since the slider 10 is supported only by the first springs 18, the focus control is stabilized, and the slider holder 13 is fixed to the optical pickup carriage 12. The second spring 19 (19a / 19b) / 19 (19a /
By being supported only by 19b), the tracking control is stabilized.

FIG. 11 shows the result of obtaining the track error amount in the same manner as in FIG. As can be seen from this figure, it can be confirmed that the local track error as shown in FIG. 7 is reduced and the maximum track error amount is as small as 0.015 μm.

The optical pickup 51 of the present embodiment
In this embodiment, the tracking control is stabilized in addition to the focus control.
An embodiment in which a configuration in which a tracking control signal is supplied via the second springs 19 is also conceivable.

[Embodiment 4] Another embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, components having the same functions as those shown in the drawings of the first, second, and third embodiments are denoted by the same reference numerals, and description thereof is omitted.

In the optical pickup 5 of the first embodiment, no magnetic field applying means is mounted on the slider 10. Therefore, as the optical recording medium 7 in the optical disc 1,
For an optical disk 1 using a magneto-optical recording material such as TbFeCo or a super-resolution magneto-optical recording material in which a plurality of layers of TbFeCo and GdFeCo are stacked, it is necessary to separately provide a magnetic field applying means. Become complicated.

Therefore, the optical pickup 5 of the present embodiment
In No. 2, an air-core coil 34 as a magnetic field applying means is mounted on the slider 53.

FIG. 12 is an enlarged sectional view of the slider 53 of the optical pickup 52 of the present embodiment. In this optical pickup 52, the second
An air-core coil 34 for supplying a recording magnetic field to the optical recording medium 7 is provided so as to surround the lens 17. Here, the air-core coil 34 has a donut-shaped recess formed around the second lens 17 on the surface of the pair of slider members 26, 26 constituting the slider 53 that faces the optical disk 1. It is wound around the portion 26a.

In order to improve the smoothness of the surface of the slider 53 facing the optical disk 1, the pair of lead wires 35 of the air-core coil 34 is provided with a lead wire passing hole 36 formed in the recess 26 a of the slider 10. From the surface of the slider 10 facing the slider holder 13. When a voltage is applied to the lead wires 35, a current flows through the air-core coil 34 to generate a recording magnetic field.

The configuration for supplying the focus control signal and the tracking control signal from the control circuit 30 in the optical pickup 52 equipped with such a slider 53 includes the configuration of the optical pickup 5 of the first embodiment and the configuration of the second embodiment. Either the configuration of the optical pickup 50 or the configuration of the optical pickup 51 of the third embodiment may be used. However, when the lead wires 35 are connected to the slider 53,
As with the focus control wires 31 described above, the lead wires 35 work as springs due to their own rigidity, which hinders the stable floating of the slider 53, and may cause unstable focus control. Therefore, it is desirable to adopt the configurations of the second and third embodiments.

More preferably, the configuration of the third embodiment is employed, and the second spring 19.1 is used as a line for supplying a focus control signal in the third embodiment.
9, the second spring 19 is divided into two parts.
Any one of 9a and 19b is further divided into two,
The first springs 18 and the conductors or electrodes for supplying signals to the first springs 18 are also divided into two parts, and one of them is a lead-out conductor 35 for supplying electric power to the air core coil 34.・ Connect to 35.

In this way, even in the configuration in which the air-core coil 34 is mounted, the slider 53
· Supported by only the slider holder 18 and the slider holder 13
Are also supported only by the second springs 19, 19,
Focusing and tracking are more stable.

It is not necessary to supply power to the air core coil 34 via both the first springs 18 and the second springs 19, and the first springs 18 and 18 or the second springs 19 Focusing or tracking can be stabilized even if performed through only one of the nineteen.

Next, the results of examining the recording / reproducing performance of the optical pickup 52 having the above configuration will be described.

In examining the recording / reproducing performance, the depression 26a formed in the slider 53 has an inner diameter of 0.15 m.
m, an outer diameter of φ1.5 mm, and a depth of 0.1 mm, and a conductive wire having a diameter of 40 μm was wound therein, thereby forming an air-core coil 34. Then, it is directly connected to a voltage power supply from the lead wire 35 having a diameter of 0.1 mm formed in the recessed portion 26a of the slider 53 to the lead wire 35 drawn out to the surface of the slider 53 facing the slider holder 13. Power was supplied. That is, in this performance check, the lead wires 35 slightly hinder the stable floating of the slider 53.

The optical disk 1 has a thickness of 1.2.
a 120 nm thick Ag reflective film, a 20 nm thick SiN interference film, and a 30 nm thick T
bFeCo recording film, 5 nm thick AlN intermediate layer, 3 film thickness
An optical recording medium 7 composed of a 0 nm GdFeCo reproducing layer and an AlN interference film having a thickness of 40 nm was sequentially laminated, and further, a protective coat 8 composed of an ultraviolet curable resin was formed with a thickness of 50 μm. This optical disc 1 is a super-resolution magneto-optical disc in which magnetization information of a recording layer only in a region where the temperature is increased is transferred to a reproducing layer by magnetostatic coupling. Also, the optical disk 1
On the substrate having a depth of 3, a concave and convex guide track in which a land and a groove having a width of 0.25 μm are spirally formed.
It is formed at 0 nm.

After attaching such an optical disk 1 to a spindle and rotating it at 3000 rpm, as shown in FIG. 10, the configuration of the optical pickup 51 of the third embodiment is adopted to bring the optical disk 51 close to the optical disk 1 and After setting the distance between the slider 1 and the slider 53 to about 10 μm, focus control and tracking control were performed on the concave and convex guide tracks on the optical disk 1, and the recording / reproducing characteristics were examined.

Here, recording was performed by applying a high-frequency rectangular voltage to the air-core coil 34 such that the recording power at the exit portion of the second lens 17 was 5 mW and the magnetic domain pattern to be recorded had a period of 0.2 μm. .

When the above recording signal was reproduced with the reproducing power at the output portion of the second lens being 1.5 mW, 39.
A CNR (signal-to-noise ratio) of 5 dB was obtained, and it was confirmed that good recording and reproduction were performed.

Further, the configuration described above as a more desirable configuration is adopted, and the first leaf spring 18 having conductivity is used.
When the power for generating the recording magnetic field is supplied to the lead wires 35 via the second leaf springs 19 and the conductive second leaf springs 19, the focus control and the tracking control are further stabilized, and the recording conditions similar to those described above are obtained. And under regeneration conditions, a CNR of 41.0 dB was obtained, and a CN of 1.5 dB was obtained.
The improvement of R was confirmed.

In each of the above embodiments,
Although the plurality of lenses constituting the condensing lens means are configured as two, three or more lenses capable of further increasing the NA may be used. In this case, at least one lens interval is set to the same value. The same effect can be obtained by controlling with the piezoelectric element layer provided on the slider.

[0115]

As described above, in the optical pickup of the present invention, the condensing lens means comprising a plurality of lenses for condensing the light beam on the optical disk is provided on the slider floating above the optical disk surface by the rotation of the optical disk. Mounted, and
The distance between the plurality of lenses is controlled by a piezoelectric element layer mounted on the slider.

As a result, the slider follows the optical disk surface, so that the wavefront aberration can be suppressed.
Since the lens interval of the plurality of lenses constituting the condensing lens means is controlled by the piezoelectric element layer, it is possible to easily perform focusing and converge the light beam on the optical disk, and to increase the thickness and tilt of the optical disk. Can easily respond to the dynamic fluctuation of In addition, since all of the plurality of lenses constituting the condensing lens means are mounted on the slider, each lens does not shift in the track direction during tracking, and a plurality of lenses constituting the condensing lens means are provided. Even if the NA is increased, the optical axis does not shift between a plurality of lenses, and the shape of the condensed spot on the optical disk can be made a good circular shape.

As a result, it is possible to maintain good recording / reproducing characteristics even if a condensing lens means composed of a plurality of lenses is used in order to increase the NA. Is achieved.

As described above, according to the optical pickup of the present invention, in the optical pickup having the above-mentioned structure, the slider is held by the slider holding member via the first elastic member for urging the slider toward the optical disk. And
The first elastic member is made of a conductive material, and power is supplied to the piezoelectric element layer via the first elastic member.

As a result, the state of the air bearing (air film) formed between the slider and the optical disk surface is stabilized by the rotation of the optical disk, so that the wavefront aberration can be more effectively suppressed. In addition, since power is supplied to the piezoelectric element layer via the first elastic member, not only cost reduction can be achieved, but also stable flying of the slider is not hindered, and stable focusing is achieved. It also has the effect of being realized.

As described above, according to the optical pickup of the present invention, in the optical pickup having the above-mentioned structure, the slider holding member for holding the slider is a second elastic member for supporting the slider holding member so as to swing in the track direction. , And is driven in the track direction by an actuator held by a slider holder, wherein the second elastic member is made of a conductive material.
The power is supplied to the actuator via the elastic member.

As a result, even if the optical disk has an eccentricity, it can be followed by performing tracking,
Since the power is supplied to the actuator provided on the slider holder via the second elastic member, the cost can be reduced, and the swing of the slider holder in the track direction is prevented. This is also effective in that more stable tracking is realized without being performed.

As described above, according to the optical pickup of the present invention, in the optical pickup having the above-mentioned structure, the slider is held by the slider holding member via the first elastic member for urging the slider toward the optical disk. The slider holder is held by the carriage via a second elastic member that supports the slider holder so as to swing in the track direction, and is driven in the track direction by an actuator held by the slider holder. Configuration,
The first elastic member and the second elastic member are both made of a conductive material, and power is supplied to the piezoelectric element layer via the first elastic member and the second elastic member. The power is supplied to the actuator via the elastic member.

As a result, the state of the air bearing is stabilized, so that the wavefront aberration can be more effectively suppressed, and the optical disk having the eccentricity by performing the tracking can follow. In addition to this, power is supplied to the piezoelectric element layer via the first elastic member and the second elastic member, and power is supplied to the actuator via the second elastic member. The effect that focusing and tracking are realized is also exhibited.

As described above, the optical pickup of the present invention is characterized in that, in the optical pickup having the above-described configuration, a magnetic field applying unit is mounted on the slider.

When a magneto-optical recording material is used as a recording material in an optical disk (a magneto-optical disk), it is necessary to apply a magnetic field to the optical disk. Is mounted, so that the structure of the optical disk device on which the optical pickup is mounted can be further simplified as compared with a configuration in which a magnetic head such as a slider on which a magnetic field applying unit is mounted is separately provided.

As described above, according to the optical pickup of the present invention, in the optical pickup having the above-mentioned structure, the slider is held by the slider holding member via the first elastic member for urging the slider toward the optical disk. And
The first elastic member is made of a conductive material, and power is supplied to the magnetic field applying means via the first elastic member.

As a result, the state of the air bearing (air film) formed between the slider and the optical disk surface is stabilized by the rotation of the optical disk, so that the wavefront aberration can be more effectively suppressed. And power is supplied to the magnetic field applying means via the first elastic member, so that the cost can be reduced as in the case of supplying power to the piezoelectric element layer mounted on the slider. Needless to say, the stable floating of the slider is not hindered, so that more stable focusing can be achieved.

As described above, according to the optical pickup of the present invention, in the optical pickup having the above-described structure, the slider holding member for holding the slider is a second elastic member for supporting the slider holding member so as to swing in the track direction. , The second elastic member is made of a conductive material, and power is supplied to the magnetic field applying means via the second elastic member. I have.

With this arrangement, even if the optical disk has eccentricity, the tracking can be performed by providing the actuator by providing the actuator, and the optical disk can be applied to the magnetic field applying means provided on the slider holder through the second elastic member. Since power is supplied, the cost can be reduced as well as the power supply to the actuator held by the slider holder, and the swing of the slider holder in the track direction is hindered. Since no tracking is performed, an effect of achieving more stable tracking is also achieved.

As described above, according to the optical pickup of the present invention, in the optical pickup having the above-mentioned structure, the slider is held by the slider holding member via the first elastic member for urging the slider toward the optical disk. And the slider holding member is held by a carriage via a second elastic member that supports the slider holding member so as to swing in the track direction. The second elastic member is made of a conductive material, and power is supplied to the magnetic field applying means via the first elastic member and the second elastic member.

As a result, the state of the air bearing is stabilized, so that the wavefront aberration can be more effectively suppressed. Further, by providing an actuator, tracking can be performed even if the optical disk has eccentricity. In addition, since power is supplied to the magnetic field applying means via the first elastic member and the second elastic member, the effect of achieving stable focusing and tracking is also achieved.

Further, the optical disc apparatus of the present invention is characterized by including the above-described optical pickup of the present invention as described above.

As a result, it is possible to provide an optical disk device capable of realizing high-density recording and reproduction with a high NA.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a cross-sectional view of an optical pickup.

FIG. 2 is a plan view of the optical pickup of FIG.

FIG. 3 is an enlarged sectional view of a main part showing a slider part of the optical pickup of FIG. 1;

FIG. 4 is an explanatory diagram showing a main configuration of an optical disk device equipped with the optical pickup of FIG. 1;

FIG. 5 is an explanatory diagram schematically showing a schematic configuration of an optical disk device on which the optical pickup of FIG. 1 is mounted.

FIG. 6 is an explanatory diagram showing a focus error amount in the optical pickup of FIG. 1;

FIG. 7 is an explanatory diagram showing a track error amount in the optical pickup of FIG. 1;

FIG. 8 shows another embodiment of the present invention, and is a cross-sectional view of an optical pickup.

FIG. 9 is an explanatory diagram showing a focus error amount in the optical pickup of FIG. 8;

FIG. 10 shows still another embodiment of the present invention, and is a cross-sectional view of an optical pickup.

11 is an explanatory diagram showing a track error amount in the optical pickup of FIG.

FIG. 12 shows still another embodiment of the present invention, and is a cross-sectional view of a slider portion of an optical pickup.

FIG. 13 is a partially enlarged sectional view of a conventional optical pickup.

[Explanation of symbols]

 Reference Signs List 1 optical disk 5 optical pickup 9 light beam 10 slider 12 optical pickup carriage (carriage) 13 slider holder (slider holder) 15 piezoelectric element layer 16 first lens (condensing lens unit) 17 second lens (condensing lens unit) 18 First spring (first elastic member) 19 Second spring (second elastic member) 20 Track direction 21 Permanent magnet (actuator) 22 Coil (actuator) 34 Air-core coil (magnetic field applying means)

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) G11B 11/105 G11B 11/105 566F F-term (Reference) 5D075 AA03 CD01 CD09 CD17 CE17 CF08 EE03 5D118 AA11 BA01 BB01 BB06 BB07 CA11 DC03 EA08 EA11 FA11 FB12 5D119 AA11 AA22 BA01 BB01 BB04 BB05 CA06 DA01 DA05 EA03 EB02 JA42

Claims (9)

[Claims] 1. A condensing lens means comprising a plurality of lenses for condensing a light beam on an optical disk is mounted on a slider which floats above the surface of the optical disk by rotation of the optical disk, and a lens interval between the plurality of lenses. Is controlled by a piezoelectric element layer mounted on the slider. 2. The slider according to claim 1, wherein the slider is held by a slider holder via a first elastic member for urging the slider toward the optical disk, wherein the first elastic member is made of a conductive material. The optical pickup according to claim 1, wherein power is supplied to the piezoelectric element layer via the first elastic member. 3. A slider holding member for holding the slider is held by a carriage via a second elastic member which supports the slider holding member so as to be swingable in a track direction, and is provided on an actuator held by the slider holding member. The second elastic member is made of a conductive material, and electric power is supplied to the actuator via the second elastic member. 2. The optical pickup according to 1. 4. The slider according to claim 1, wherein the slider is held by a slider holder via a first elastic member for urging the slider toward the optical disk, and the slider holder moves the slider holder in the track direction. The first elastic member and the second elastic member are configured to be held by the carriage via a second elastic member that is swingably supported and driven in the track direction by an actuator held by a slider holder. The elastic members are both made of a conductive material. Power is supplied to the piezoelectric element layer via the first elastic member and the second elastic member, and power is supplied to the actuator via the second elastic member. The optical pickup according to claim 1, wherein power is supplied. 5. The optical pickup according to claim 1, wherein a magnetic field applying means is mounted on said slider. 6. The slider according to claim 1, wherein the slider is held by a slider holder via a first elastic member for urging the slider toward the optical disk, wherein the first elastic member is made of a conductive material. The optical pickup according to claim 5, wherein power is supplied to the magnetic field applying means via the first elastic member. 7. A slider holding body for holding said slider, wherein said slider holding body is held by a carriage via a second elastic member which supports the slider holding body so as to be swingable in a track direction. 6. The optical pickup according to claim 5, wherein the elastic member is made of a conductive material, and power is supplied to the magnetic field applying means via the second elastic member. 8. The slider according to claim 1, wherein said slider is held by a slider holder held by a carriage via a first elastic member for urging the slider toward the optical disk. A first elastic member and a second elastic member, each of which is made of a conductive material, wherein the first elastic member and the second elastic member are both made of a conductive material; 6. The optical pickup according to claim 5, wherein power is supplied to said magnetic field applying means via said first elastic member and said second elastic member. 9. An optical disk device comprising the optical pickup according to claim 1. Description: