JP2001283452A - Magneto-optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a distance between a magneto-optical disk and an objective lens with high precision. SOLUTION: This magneto-optical head is provided with a plate-like substrate 2 which is arranged over the magneto-optical disk 100, a ring type magnetic coil 4 which is integrally formed with the substrate 2, generates a magnetic field in the thickness direction of the substrate 2 and impresses the magnetic field in the thickness direction of the magneto-optical disk 100, an objective lens 3 which is provided in the nearly central position of the magnetic coil 4 and is arranged within the substrate 2, and a deformable element 5 which is formed around the magnetic coil 4 and the objective lens 3 and is arranged in contact with the substrate 2. The distance between the magneto-optical disk 100 and the objective lens 3 is changed with the substrate deflected by the deformable element 5 being deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical device for irradiating light and applying a magnetic field to record information on a magneto-optical disk and irradiating light to reproduce information recorded on the magneto-optical disk. About the head.

[0002]

2. Description of the Related Art Conventionally, many magneto-optical heads for recording / reproducing on / from a magneto-optical disk have a magnetic plate and an objective lens mounted on a plate-shaped substrate called a slider.

When recording on a magneto-optical disk with such a magneto-optical head, light is incident on an objective lens by an optical system, and a spot is formed on the magneto-optical disk by the objective lens. Thus, the temperature of the recording area of the magneto-optical disk is raised to the Curie point, and a magnetic field is applied by the magnetic coil.

When reproducing information recorded on a magneto-optical disk with a magneto-optical head, the rotation angle and ellipticity of the light illuminated and reflected on the magneto-optical disk have been detected.

[0005]

By the way, in a magneto-optical head corresponding to the recent increase in the density of a magneto-optical disk, it is necessary to control the distance from the magneto-optical disk with high precision.

That is, in order to form a beam spot having a small spot diameter on a magneto-optical disk, it is necessary to use an objective lens having a high numerical aperture NA. It has been proposed to use a numerical aperture NA of the objective lens of about 0.9 from 0.55 and 0.6 currently used.
When the numerical aperture NA is increased, the spot diameter formed on the magneto-optical disk when the distance between the magneto-optical disk and the magneto-optical head deviates greatly changes, and there is a possibility that recording and reproduction cannot be performed. Therefore, it is necessary to control the distance between the magneto-optical disk and the magneto-optical head with higher accuracy.

In a magneto-optical head having a slider provided with an objective lens and a magnetic coil, the slider floats on the magneto-optical disk by utilizing the airflow caused by rotation of the magneto-optical disk, and the distance from the magneto-optical disk is reduced. Although it was controlled, the floating controllability during low-speed rotation was unfavorable. That is,
During low-speed rotation, the airflow generated by the magneto-optical disk and received by the slider is weakened, and the change in the distance between the magneto-optical head and the magneto-optical disk is often increased.

Accordingly, the present invention has been proposed in view of the above-described circumstances, and has as its object to provide a magneto-optical head capable of controlling the distance between a magneto-optical disk and an objective lens with high accuracy. Aim.

[0009]

In order to solve the above-mentioned problems, a magneto-optical head according to the present invention comprises a plate-shaped substrate disposed on a magneto-optical disk and an integrated substrate. A ring-shaped magnetic coil for generating a magnetic field in the thickness direction of the base by applying a magnetic field in the thickness direction of the magneto-optical disk; and a ring-shaped magnetic coil provided substantially at the center of the ring of the magnetic coil and disposed in the base. An objective lens, and a deformation element formed around the magnetic coil and the objective lens and arranged in contact with the base.

According to such a magneto-optical head, when the deformable element is deformed, the base is bent to change the distance between the magneto-optical disk and the objective lens.

[0011]

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

The present invention is applied to a magneto-optical head 1 as shown in FIGS. 1 and 2, for example.

As shown in FIG. 1, the magneto-optical head 1 has a base 2, an objective lens 3 embedded in the base 2, and a magnetic head formed on the base 2 on the side where the magneto-optical disk 100 is provided. It includes a coil 4, a deformation element 5 formed on the light incident side of the base 2, and a protection member 6 formed on the side of the base 2 where the magneto-optical disk 100 is formed and on the outer peripheral side of the magnetic coil 4. The magneto-optical head 1 includes a magneto-optical disk 100
During recording / reproducing, the distance D to the magneto-optical disk 100 is controlled so as to face the magneto-optical disk 100.

The base 2 is made of a material such as a synthetic resin whose shape can be deformed by stress. This base 2 is
It is molded into a plate having a thickness of about 50 μm. The base 2 also has an opening 2a that allows laser light to enter the objective lens 3.

The objective lens 3 has, for example, a numerical aperture NA of 0.1.
It is made of a material having a high numerical aperture of about 6 to 0.9. The objective lens 3 receives a laser beam from an optical system (not shown) from the side of the base 2 and forms a laser spot on the recording / reproducing area of the magneto-optical disk 100.

The magnetic coil 4 is formed in a ring shape and formed on the magneto-optical disk 100 side of the base 2. The magnetic coil 4 applies a magnetic field in the thickness direction of the magneto-optical disk 100 when a current is supplied.

The deforming element 5 is formed around the objective lens 3 and the magnetic coil 4 as shown in FIG. The deforming element 5 is an element that deforms according to a voltage. The deforming element 5 is, for example, a piezoelectric element whose shape is changed by applying a voltage.

In this embodiment, the deformation elements 5 are arranged at four places around the objective lens 3 and the magnetic coil 4, and different voltages are applied to the deformation elements 5, so that the base 2 is deformed.
To change the shape.

The protection member 6 is provided on the magneto-optical disk 100 side of the base 2. The protection member 6 is provided for the purpose of preventing collision between the magneto-optical head 1 and the magneto-optical disk 100 during recording and reproduction on the magneto-optical disk 100.

In the magneto-optical head 1 configured as described above, a driving voltage according to the focus control signal is supplied to the deformable element 5, whereby the deformable element 5 is deformed.
By bending into the shape shown in FIG. 3A, the distance D ₁ from the magneto-optical disk 100 is reduced, and by bending into the shape shown in FIG. D
₂ is lengthened.

A recording / reproducing apparatus 10 having such a magneto-optical head 1 is configured as shown in FIG.

When a recording command is input from an external host computer and a recording signal is input, the recording / reproducing apparatus 10 outputs a disk drive via an input / output control unit 11, an encoding / decoding unit 12, and a recording control unit 13. It is configured to output a recording signal to the unit 14. The recording / reproducing apparatus 10 reproduces data recorded on the magneto-optical recording medium 1 by the disk drive unit 14 according to a reproducing command from a host computer.
It is configured to output to the outside as a reproduction signal via the RF signal processing unit 15, the encoding / decoding unit 12, and the input / output control unit 11.

The disk drive section 14 drives the magneto-optical recording medium 1 to rotate, irradiates the magneto-optical recording medium 1 with light, and performs recording and reproduction on the magneto-optical recording medium 1, an actuator 22, and an optical drive. A system 23, a laser driver 24, a head amplifier 25, and a matrix amplifier 26 are provided.

The spindle motor 21 comprises a motor mechanism for generating a driving force for driving the magneto-optical recording medium 1 to rotate. Based on a control signal from the rotation control unit 16, the spindle motor 21 is configured to perform, for example, CLV (Constant Line Velocity) during recording / reproduction on the magneto-optical recording medium 1.
The magneto-optical recording medium 1 is rotationally driven in accordance with a (city) method or a CAV (Constant Angle Velocity) method.

The actuator 22 is provided for the magneto-optical recording medium 1.
And an objective lens that collects recording light and reproduction light and detects reflected light. The actuator 22 irradiates the magneto-optical recording medium 1 with recording light and reproduction light from the optical system 23 via an objective lens, and emits reflected light from the magneto-optical recording medium 1 to the optical system 23.

Further, the actuator 22 has a minute driving mechanism including a coil and a magnet for minutely moving the objective lens. The actuator 22 minutely moves the objective lens based on a focus drive signal or a tracking drive signal from the focus tracking control unit 17.

The actuator 22 is moved in the radial direction of the magneto-optical recording medium 1 by a thread motor (not shown). The actuator 22 is moved in the radial direction of the magneto-optical recording medium 1 by supplying a feed drive signal from the feed servo control unit 18 to a thread motor, and arranges an objective lens immediately below a track position for recording and reproduction.

The optical system 23 emits light emitted from a light source to the actuator 22 as recording light in accordance with a laser drive signal from a laser driver 24. Also, the optical system 23
Detects the reflected light emitted from the actuator 22 and reflected by the magneto-optical recording medium 1 with a photodetector, and outputs a photodetection signal to the head amplifier 25.

The laser driver 24 generates a laser drive signal for driving a light source included in the optical system 23.
The laser driver 24 controls the light source to emit recording light with the laser power at the time of recording at the time of recording, and emits reproduction light at the laser power at the time of reproduction at the time of reproduction.

The head amplifier 25 amplifies the photodetection signal from the photodetector included in the optical system 23 to a predetermined gain and outputs the signal to the matrix amplifier 26. The matrix amplifier 26 performs a predetermined process on the light detection signal from the head amplifier 25 and outputs a signal extracted from the light detection signal to the RF signal processing unit 15 and the focus tracking control unit 17.

The input / output control unit 11 comprises an interface circuit for inputting a recording signal from an external host computer and outputting data recorded on the magneto-optical recording medium 1 as a reproduction signal. This input / output control unit 11
The use of a RAM (Random Access Memory) 18 as a work area controls the exchange of signals between the recording / reproducing device 10 and the outside. The input / output control unit 11 includes:
A recording command or a reproduction command is input from an external host computer, and the input various commands are transmitted to the CPU 20.
Output to

The encoding / decoding unit 12 performs an encoding process for converting the recording signal input from the input / output control unit 11 into a format for recording on the magneto-optical recording medium 1. Encoding processing is performed according to a predetermined format, and the encoded data is output to the disk drive unit 14 via the recording compensation unit 13. At this time, the encoding / decoding unit 12 performs the encoding process using the RAM 19 as a work area.

The encoding / decoding unit 12
When a reproduction signal reproduced from the magneto-optical recording medium 1 is input from the RF signal processing unit 15, the decoding processing for outputting the reproduction signal recorded on the magneto-optical recording medium 1 to the outside is performed. Output to the output control unit 11. At this time, the encoding / decoding unit 12 performs a decoding process using the RAM 19 as a work area.

The RF signal processing unit 15 performs baseband processing on the reproduced signal from the matrix amplifier 26 to detect 0 and 1 and outputs the detected signal to the encoding / decoding unit 12.

The recording / reproducing apparatus 10 includes a focus tracking controller 17 for controlling focus and tracking during recording / reproducing, a feed servo controller 18 for controlling the position of the actuator 22 in the radial direction of the optical disk, and rotation of the spindle motor 21. It comprises a rotation control unit 16 for controlling the number, and a CPU (Central Processing Unit) 20 for controlling each unit constituting the recording / reproducing apparatus 10.

The focus tracking control unit 17 includes:
A focus error signal and a tracking error signal are input from the matrix amplifier 26. The focus tracking control unit 17 corrects the focus error and the tracking error by driving the actuator 22 based on the focus error signal and the tracking error signal according to the control signal from the CPU 20.

When the distance between the magneto-optical disk 100 and the magneto-optical head 1 is minutely controlled, the focus tracking control section 17 applies a focus control signal to the deformable element 5 to thereby control the magneto-optical head as shown in FIG. By controlling the distance D, the distance D between the magneto-optical head 1 and the magneto-optical disk 100 is controlled to achieve focusing.

The feed servo control section 18 outputs a feed servo signal for positioning the actuator 22 on a predetermined track on the magneto-optical recording medium 1 to a thread motor in accordance with a control signal from the CPU 20.

The rotation control section 16 controls the rotation of the magneto-optical recording medium 1 in accordance with a control signal from the CPU 20.

The CPU 20 performs control by outputting a control signal to each unit constituting the recording / reproducing apparatus 10. This CP
A recording command and a reproduction command are input to U20 from an external host computer via the input / output control unit 11.

According to the recording / reproducing apparatus 10 having the above-described magneto-optical head 1, when focus control is required at the time of recording / reproducing, the shape of the base 2 is controlled as shown in FIG. By changing the distance between the disk 100 and the magneto-optical head 1, the distance between the magneto-optical disk 100 and the magneto-optical head 1 can be controlled with high accuracy.
The distance between the objective lens 3 and the magneto-optical disk 100 can be controlled with high accuracy.

Further, according to the magneto-optical head 1, even if the numerical aperture of the objective lens 3 is as high as 0.9,
The objective lens 3 and the magneto-optical disk 1 due to the deformation of the deformable element 5 as well as the mechanical distance control of the actuator 22
00 can be controlled, and the magneto-optical disk 1 can be controlled.
It is possible to suppress a large change in the spot diameter formed on the magneto-optical disk when the distance from 00 is shifted.

Further, according to the recording / reproducing apparatus 10, even if the rotation speed of the magneto-optical disk 100 changes and the flying characteristics of the magneto-optical
The distance between 0 and the magneto-optical head 1 can be controlled with high accuracy.

In the present embodiment, an example in which the deformation element 5 is provided on the magneto-optical head 1 to control the distance D from the magneto-optical disk 100 has been described. However, FIGS. 5A and 5B show the example. Slider 3 having a magnetic head 31 at the tip as shown in FIG.
2 is also applicable. The slider 32 includes a deformable element 5 on the rail 33, and controls the distance between the magnetic head 31 and the magnetic disk 34 by deforming the deformable element 5 sliding on the magnetic disk 34 in the height direction A. As a result, the slider 32 moves the magnetic head 31 and the magnetic disk 3
4 can be controlled with high precision, and stable recording and reproduction can be performed.

[0045]

According to the magneto-optical head of the present invention, at the time of recording / reproducing on / from the magneto-optical disk, the deformable element is deformed to deflect the base and change the distance between the magneto-optical disk and the objective lens. The distance between the magneto-optical disk and the objective lens can be controlled with high precision.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magneto-optical head to which the present invention is applied.

FIG. 2 is a perspective view showing a magneto-optical head to which the present invention is applied.

FIG. 3 is a diagram for explaining how a base of a magneto-optical head to which the present invention is applied is bent.

FIG. 4 is a block diagram illustrating a configuration of a recording / reproducing apparatus to which the present invention has been applied.

FIG. 5 is a side view and a plan view showing the slider.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 magneto-optical head, 2 base, 3 objective lens, 4 magnetic coil, 5 deformation element, 10 recording / reproducing device, 17
Focus tracking controller

Claims (1)

[Claims] 1. A plate-shaped base disposed on a magneto-optical disk, and a magnetic field is generated in the thickness direction of the magneto-optical disk by generating a magnetic field in a thickness direction of the base. A ring-shaped magnetic coil to be applied, an objective lens provided substantially at the center of the ring of the magnetic coil, and disposed in the base, and formed around the magnetic coil and the objective lens and disposed in contact with the base. A magneto-optical head comprising: a deformed element.