JPH08273230A - Mgneto-optical recording and reproducing device - Google Patents

Abstract

PURPOSE: To comparatively easily obtain a high frequency high magnetic field required for magnetic field modulation recording. CONSTITUTION: This is a magneto-optical recording and reproducing device for recording data on a magneto-optical disk by modulating the magnetic field. The device is composed of an optical pickup means 14 for irradiating a recording surface of the magneto-optical disk 12 with light, a recording head 24 arranged in a position opposite to this optical pickup means via the magneto- optical disk, a magnetic field generating means 30 connected to the recording head for generating the high frequency high magnetic field and a supply means 28 for recording data to be impressed on the magnetic field generating means. The high frequency high magnetic field is modulated by the recording data, and this recording data is recorded on the magneto-optical disk. For the magnetic field generating means, a resonance power amplifier using a high frequency signal is used. Thus, the high frequency high magnetic field can easily be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording / reproducing apparatus which records and reproduces data by using a magneto-optical disk, and particularly when recording data by magnetic field modulation, a high frequency high magnetic field for data recording is used. The present invention relates to a magneto-optical recording / reproducing apparatus that can be generated relatively easily and that record data can be recorded on a magneto-optical disk by modulating the high-frequency high magnetic field with the record data.

[0002]

2. Description of the Related Art As a method of recording data using a magneto-optical disk (MO disk), two methods, an optical modulation recording method and a magnetic field modulation recording method, are well known. Among them, the optical modulation recording method has drawbacks such that the range of recording laser power (recording power margin) capable of obtaining a stable reproduction signal is small, and that data cannot be recorded until the recorded data is erased. On the other hand, it is known that the magnetic field modulation method has advantages such as a large recording power margin and overwriting, as is well known.

[0003]

However, in this magnetic field modulation recording method, since it is necessary to record data while applying a large magnetic field to the magneto-optical disk, there is no reasonable high magnetic field generating means, so it is high. A magneto-optical recording / reproducing device with a transfer rate has not been realized.

Since a desired high magnetic field cannot be obtained, it is necessary to concentrate the magnetic field on the magneto-optical disk as much as possible.
Therefore, the gap between the disc and the recording head is 100-25.
It must be very narrow, 0 μm.

On the other hand, since a magneto-optical disk usually has a surface deviation, in order to record data while avoiding a collision of the recording head due to the surface deviation, an actuator is provided in the recording head and a gap facing the disk surface is provided. A servo system that uses an actuator to keep it constant is required. If the required high magnetic field can be obtained relatively easily, the magnetic field modulation recording method can be realized at low cost and the high transfer rate can be achieved.

Therefore, the present invention has solved such a conventional problem, and employs a magnetic field modulation recording system capable of recording data by generating a high magnetic field with a relatively simple structure. A magneto-optical recording / reproducing apparatus is proposed.

[0007]

In order to solve the above-mentioned problems, a magneto-optical recording / reproducing apparatus according to the present invention described in claim 1 comprises an optical pickup means for irradiating a recording surface of a magneto-optical disk with light. A recording head disposed at a position facing the optical pickup means with the magneto-optical disc interposed therebetween, a magnetic field generating means connected to the recording head and generating a high magnetic field at a high frequency, and a magnetic field generating means. The recording data is supplied onto the magneto-optical disk by modulating the high-frequency high magnetic field with the recording data, and the recording data is recorded on the magneto-optical disk.

[0008]

The coil of the recording head also functions as a resonance element of the magnetic field generation means, and a resonance current is passed through the coil to generate a high magnetic field having a single high frequency. The current flowing through the recording head coil is Q times the current determined by the resonance circuit during resonance, so that a high magnetic field can be obtained.

Since it is a high frequency magnetic field, it is not reproduced as a reproduction RF signal. When the recording signal is added to this high frequency magnetic field, the magnitude of the high frequency magnetic field is modulated (level shifted) by this recording data. Data will be recorded on the magneto-optical disk.

[0010]

Next, an example of a magneto-optical recording / reproducing apparatus adopting the magnetic field modulation recording system according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a concrete example of a magneto-optical recording / reproducing apparatus 10 according to the present invention. An optical pickup means 14 is slidable on the one surface side of a magneto-optical disk 12 in the radial direction of the disk. Will be distributed. Although not shown in the figure, the optical pickup means 14 incorporates a laser diode LD as a light source, and drives an LD driver 20 to excite a laser. The laser light 18 emitted from the laser diode LD is applied to the recording film (not shown) of the magneto-optical disk 12 via the objective lens 16. The laser light reflected from the recording film passes through the same objective lens 16 and is applied to a light receiving element such as a photodiode (not shown) incorporated in the optical pickup means 14 to reproduce the data (signal) on the disc.

As is well known, a light amount monitor circuit (not shown) is connected to the LD driver 20 so that the laser diode LD is excited with a constant light amount during recording and reproduction. Further, a servo circuit 22 for performing focus adjustment of the optical pickup means 14 and tracking adjustment for the disk 12 is provided in the optical pickup means 14.

In the present invention, in addition to the above structure, the optical pickup means 14 is provided with the magneto-optical disk 12 interposed therebetween.
A recording head 24 used for recording a signal is arranged at a position facing the. In this example, the recording head 24 has a fixed head configuration and is arranged to face the disk 12 with a predetermined gap.

The recording head 24 has a bottomed cylindrical core 25 having an E-shaped cross section having a central leg, and a center magnetic leg (central leg).
A coil 26 for generating a magnetic field is wound around the
The coil 26 is supplied with a high frequency signal and a recording signal for generating a high frequency high magnetic field.

Therefore, the magnetic field generating means 30 is provided, and a high-current high-frequency signal is generated here. When a high-current high-frequency signal is supplied to the above-mentioned coil 26, a high-frequency high magnetic field is generated by the high-frequency current flowing through the coil 26, and this high-frequency high magnetic field forms a closed magnetic path passing through the disk as shown in the figure. .

A signal to be recorded is supplied from the supplying means 28 to the high frequency and high magnetic field generating means 30. Supply means 28
Is simultaneously supplied with the system clock CK. The system clock CK is used as a high frequency signal for generating a high frequency magnetic field as described later.

FIG. 2 shows the means 30 for generating a high frequency and high magnetic field.
When a recording signal (analog signal or digital signal) as shown in B is supplied and added to the high frequency signal, the high frequency magnetic field shown in FIG. 2A is modulated (shifted) by this recording signal, so that it passes through the disk plate surface. The change in the magnetic field shown in FIG. 2C is stored in the disc and data is recorded. Of course, a high-frequency magnetic field is also recorded in the disk, but in the non-modulated state, the sum of magnetic field changes (changes of NS poles) is averaged so that it is not reproduced as a reproduction RF signal. Therefore, as a result, the magnetic pole change due to the recording signal is stored in the disk.

FIG. 3 shows a concrete example of the magnetic field generating means 30 and the signal supplying means 28 described above. The magnetic field generating means 30 includes a high frequency power amplifier 32 and a resonance circuit 40. As the high frequency power amplifier 32, a power amplifier (class C amplifier) often used as the final stage of the transmission circuit can be used. A signal (high frequency signal) for generating a high frequency magnetic field (alternating magnetic field) is supplied to the terminal 34.

Since it is necessary to generate a high frequency magnetic field,
The frequency of the high frequency signal is selected to be at least three times the highest frequency of the signal to be recorded. When the maximum recording frequency is up to about 10 MHz, the system clock CK of the device can be used as a high frequency signal. This is because a high frequency signal of about 40 MHz is used as the system clock CK. The high frequency signal is supplied to the base of the power transistor (power transistor) Qa via the impedance matching device 36.

The inductance elements La and Lb connected to the base and collector of the power transistor Qa are used as a bias element for the transistor, and the diode 38 connected to the inductance element La is used as a bias element for the transistor Qa. It is also used as a temperature compensation element for the transistor Qa.

A resonance circuit 40 is connected between the collector of the transistor Qa and the ground. The resonance circuit 40 has an LC series resonance circuit configuration, and the coil 26 used in the recording head 24 described above is used as the resonance coil. Coil 2
6 is divided into two parts 26a and 26b, and a resonance capacitor 42 is connected in series with the coil 26b.

When a high frequency signal is supplied to the terminal 34, the collector current of the transistor Qa is supplied from the collector side of the transistor Qa to the resonance circuit 4.
When the resonance circuit 40 resonates, a current Q times the resonance circuit 40 becomes a resonance current. In the power amplifier (resonant power amplifier) 32, a large current can flow through the power transistor Qa, so a current Q times the current is supplied to the resonant circuit 4a.
Can be flown to zero. Therefore, the magnetic field generated in the coil 26 also increases, and a magnetic field sufficiently satisfying the high magnetic field (300 to 500 Oe) required for magneto-optical modulation recording can be obtained. The transmission power amplifier 32 is easily available and the cost is low.

As shown in FIG. 3, the recording signal supply means 28 has a differential amplifier 50 composed of a pair of transistors Qb and Qc, and a transistor Qd is provided on the common emitter side thereof.
Is connected. A recording signal is supplied to the terminal 52, and the collector of the transistor Qc is connected to the connection midpoint q (between the coils 26a and 26b) of the resonance circuit 40.

Since a signal obtained by inverting the phase of the recording signal supplied to the terminal 52 is obtained at the collector of the transistor Qc, this signal (current) is added to the high frequency resonance current at the connection point q. As a result, an additional magnetic field of the high frequency high magnetic field due to the high frequency resonance current and the magnetic field based on the recording current is generated from the coil 26.

The magnetic field modulation recording is determined by the coercive force Hc at the time of heat drop of the disk recording film by the applied laser power and the magnitude of the applied magnetic field. The ratio of the magnitude of the magnetic field is related to the S / N ratio of the reproduced signal, but it is sufficient that the magnitude of the magnetic field based on the recording current is about 1/10 of the magnitude of the high frequency high magnetic field.

The magnetic field generated by the recording current added to the high-frequency high magnetic field causes the high-frequency magnetic field to have an offset, and the coercive force for reversing the magnetization direction of the recording film is unbalanced to record a signal. During reproduction, the imbalance in coercive force is picked up and used as a reproduction signal.

When the magnetic field generating means 30 shown in FIG. 3 is used, a high frequency high magnetic field can be obtained relatively easily. Therefore, as shown in FIG. 1, the recording head 24 is synchronized with the movement of the pickup means 14. It is possible to use a head configuration that moves by moving. Disc 12 in that case
The facing gap for can be fixed. This is because even if the recording head 24 is fixed, a sufficiently high magnetic field can be obtained, so that the recording head 24 can be arranged at the facing position that is not affected by the disc surface shake.

This means that if the disk facing position of the recording head 24 can be controlled according to the surface deviation of the disk 12, the disk facing gap can be sufficiently narrowed, and thus the magnetic field applied to the disk 12 can be low. It will be. FIG. 4 shows an example of a magneto-optical recording / reproducing apparatus 10 suitable for use in that case.

In the present invention, as shown in FIG. 4, the bottomed cylindrical core 25 of the recording head 24 is connected to the actuator 60, and the actuator 60 is driven by the output of the servo circuit 22 to drive the bottomed cylindrical core 25 and the disk plate. The facing gap with the surface is controlled to be constant regardless of surface deviation.

FIG. 5 shows a concrete example of the recording head 24 with the actuator. The bottomed cylindrical core 25 is attached and fixed to the lower surface side of the auxiliary member 62, and the sliding piece 6 of the auxiliary member 62 is fixed.
2a is inserted in the actuator 60. A pair of optical sensors 64, 6 having different heights on the lower surface of the auxiliary member 62 and facing each other with the bottomed cylindrical core 25 interposed therebetween.
6 will be placed. A pair of optical sensors 6 with an offset
Reference numerals 4 and 66 each have a light emitting portion and a light receiving portion, and the detection light is applied to the disk plate surface. The sensor output is supplied to the servo circuit 22 shown in FIG. 4, and the control output obtained from this is returned to the actuator 60.

In the servo circuit 22, a pair of optical sensors 64,
When the detection levels of 66 are compared and the comparison output (reference value) corresponds to the above-mentioned offset amount, the disc 12
It is judged that there is no distraction. If there is surface deviation, the value of the comparison output deviates from the reference value, so the vertical position of the auxiliary member 62 with respect to the actuator 60 is controlled so that this value becomes the reference value.

Even if there is surface deviation due to this position control, the opposing gap between the disk 12 and the recording head 24 can be kept constant, so the strength of the high frequency magnetic field applied to the disk 12 should be made weaker than in the case of FIG. The power consumption can be reduced accordingly.

[0033]

As described above, in the magneto-optical recording / reproducing apparatus according to the present invention, a high-frequency high magnetic field obtained by adding a recording magnetic field to a magneto-optical disk surface by supplying a high-frequency signal obtained by adding a recording signal to a recording head. The recording signal is recorded on the disc as it is given.

According to this, a high frequency and high magnetic field can be obtained relatively easily, and thus magnetic field modulation recording can be easily realized.

[Brief description of drawings]

FIG. 1 is a system diagram of essential parts showing an example of a magneto-optical recording / reproducing apparatus according to the present invention.

FIG. 2 is an explanatory diagram of magnetic field modulation recording.

FIG. 3 is a connection diagram showing a specific example of a magnetic field generation means and a signal supply means.

FIG. 4 is a system diagram of essential parts showing another example of the magneto-optical recording / reproducing apparatus according to the present invention.

FIG. 5 is a schematic cross-sectional view of a main part showing a configuration example of a recording head used at that time.

[Explanation of symbols]

 10 magneto-optical recording / reproducing apparatus 12 magneto-optical disk 14 optical pickup means 24 recording head 28 signal supplying means 30 magnetic field generating means 32 power amplifier 40 resonant circuit

Claims (6)

[Claims] 1. A magneto-optical recording / reproducing apparatus adapted to record data on a magneto-optical disk by modulating a magnetic field, wherein an optical pickup means for irradiating a recording surface of the magneto-optical disk with light and the magneto-optical disk are provided. A recording head disposed at a position facing the optical pickup means sandwiching it, a magnetic field generating means connected to the recording head for generating a high magnetic field of high frequency, and a supply means for supplying recording data applied to the magnetic field generating means. A magneto-optical recording / reproducing apparatus, characterized in that the recording data is recorded on the magneto-optical disk by modulating the high-frequency high magnetic field with the recording data. 2. A power amplifier having a resonance circuit is used as the magnetic field generating means, and a coil of the recording head is connected as a resonance element to an output end of the resonance power amplifier. 1
The magneto-optical recording / reproducing apparatus described. 3. A single high frequency signal is supplied to the resonance power amplifier used as the magnetic field generating means, and a high frequency high magnetic field is generated in the recording head coil used as the resonance element. The magneto-optical recording / reproducing apparatus according to claim 2, wherein 4. The magneto-optical recording / reproducing apparatus according to claim 2, wherein the single high-frequency signal is a signal having at least three times the maximum recording frequency. 5. The system clock of the device is used as the single high-frequency signal.
The magneto-optical recording / reproducing apparatus described. 6. The magneto-optical recording / reproducing apparatus according to claim 1, wherein the recording data is supplied to a coil of the recording head.