JPS62129962A - Photomagnetic recording carrier - Google Patents

Abstract

PURPOSE:To reduce jitter components due to variance in optimum recording condition and to improve recording density by writing a reference linear speed, recording beam diameter, optimum recording power at room temperature, etc., on a photomagnetic recording carrier. CONSTITUTION:When 12 photomagnetic disks of the same structure are manufactured by the same manufacturing method, the optimum recording power has variance from 4 to 5.6mW on conditions of a 6m/sec linear speed and a 400oe recording magnetic field. The optimum power of each disk is recorded in the 0-address sector 2 at the outermost peripheral part of the disk. When recording or reproduction is performed, the disk 1 is loaded and the signal of the 0-address sector 2 is read right after the drive is driven and stored in a memory. When a pickup is moved to a place where data is to be recorded, recording power is calculated from the signal stored in the memory, distance from the center of disk rotation, etc., and the recording is carried out with the found recording power.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magneto-optical record carrier which is an improved record carrier of a magneto-optical memory used for recording information.

BACKGROUND OF THE INVENTION In recent years, as the information society has progressed, there has been a strong desire to put rewritable large-capacity optical discs into practical use.

Among these, magneto-optical memory, which is attracting particular attention, has recently been confirmed to have unique characteristics as a digital memory.

By the way, the optimum recording conditions for a magneto-optical record carrier are determined by the material, composition, thickness, protective film or encapsulant of the magneto-optical thin film for recording.
・It is greatly affected by the material, composition, film thickness, substrate configuration, groove shape, etc. of the thin film for the sensor.

Therefore, it was necessary to determine the optimal recording laser power and the optimal recording magnetic field for each structure of magneto-optical disks, and to perform recording under these conditions.

On the other hand, even when comparing magneto-optical disks with the same structure made by the same manufacturing method, there are variations in the coercive force of the recording film, variations in the surface oxidation state, and variations in the protective film or en-
・Due to variations in factors that cannot be controlled at present, such as variations in the nitrogen bonding state and oxygen bonding state of the thin film for recording, and variations in the groove shape, the optimal recording power or recording magnetic field is within ±20 to ±30. This results in variations in the degree of correlation.

These variations in recording conditions eventually correspond to changes in recording sensitivity, resulting in changes in pulse width for recording under the same conditions. Therefore, when performing digital recording, it is necessary to suppress the jitter component to below an allowable range, and it is not possible to use a width recording method that provides information to the pulse width and can increase the recording capacity. Therefore, we have no choice but to set the recording capacity to % and use edge recording in which the rising edge or falling edge of the pulse provides information.

Problems to be Solved by the Invention However, with the above configuration, it has been impossible to provide compatibility with magneto-optical disks of different structures because the recording conditions are significantly different. Furthermore, even for magneto-optical disks with the same structure and same fabrication method, the above configuration is limited to the etch recording method in order to absorb fluctuations in recording conditions due to uncontrollable variations, and the recording density is kept low. It was getting worse.

In view of the above-mentioned problems, the present invention provides a magneto-optical record carrier that provides compatibility with magneto-optical disks of different structures, enables adoption of a width recording method, and significantly improves recording density. be.

Means for Solving the Problems To achieve this objective, the magneto-optical record carrier of the present invention comprises:
It is composed of a linear velocity determined as a standard, a recording beam diameter, an optimal recording power at room temperature, an appropriate R recording magnetic field, or both written in a part of the magneto-optical record carrier. .

Operation With this configuration, the magneto-optical disk drive reads the optimum recording power and/or the optimum recording magnetic field for the disk immediately after driving the disk, stores the results in the drive's memory, and uses the results during recording. By referring to it, it is possible to perform recording under the optimum recording conditions for each disc. Therefore, jitter components caused by variations in optimal recording conditions can be significantly reduced, which not only maintains compatibility between disks with different structures, but also enables the adoption of width recording, which greatly improves recording density. be able to.

Example Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1 Twelve magneto-optical disks having the same structure were manufactured by the same manufacturing method. The structure and manufacturing method are as follows: On a glass substrate with a diameter of 120+ mn and a thickness of 1.1 -, sectored pre-group grooves are formed by a photovolimalization method, and a protective film of 2Mqo -S i O is formed by a sputtering method.
2100rra, a-based film GdTbFaGe100m
m, a protective film of 2 Mqo, and S i of 02100 m were laminated in this order. The optimum recording power for these 12 magneto-optical disks is a linear velocity of 6 m/sec and a recording magnetic field of 400 oe.
There was variation between 4 mW and 5.6 mW.

Next, for each of the 12 disks, the respective optimum power was recorded in the 0th sector located at the outermost periphery of each disk. Note that during recording, the recording power was divided into 32 parts from 3.6 mW to 6.0 mW, converted into digital signals, and recorded using the PE modulation method. These conditions are shown in FIG.

Sector 0 2 located at the outermost circumference of the magneto-optical disk 1
is header signal 3 of sector 0 formed by uneven grooves.
This is followed by a data signal of recording power written by a magneto-optical signal.

Recording and reproduction of the magneto-optical disk on which data with such recording power was written was performed while rotating the disk at 1800 rpm. Immediately after the disk is mounted and the drive is driven, the No. ○ sector signal is read, and the data signal is stored in the memory built into the drive device.

Next, when the pickup moves to the location where data is to be recorded, the distance r (print) from the center of rotation of the disk to the location to be recorded is detected by the position detector, and is determined from the linear velocity dependence of the recording power. Empirical formula However, Prec" Recording power (mW) Po = Recording power stored in the memory (mW) R: Disc rotation speed (rpm) Calculate the recording power using the calculated recording power and use the recording laser power. , drive and record.

Here, in order to confirm the effect, the minimum recording wavelength is equivalent to 2 MHz (recording length: innermost circumference 1.4 μm).

A single frequency signal was recorded at the outermost circumference (2.8 μm).

This signal was reproduced at the φ64 position, 1o7 pulse widths were measured, and the window width o, assuming 2/7 modulation, was 5.
The frequency of errors that deviate by T, that is, 25OnSeC±41nSecj, was determined. The results are shown in Table 1. For comparison, P in the first equation. We also show the results obtained for the conventional method with constant . A comparison with the results of the conventional method reveals a significant improvement.

(>'<T Nunobiki Table 1 (Error frequency of linear recording method) Example 2 Using the same 12 disks as used in Example 1, the linear velocity was am/sec and the recording power was 4.8 mW. The optimum recording magnetic field for each disk was recorded in the first sector located at the outermost periphery of the disk.In addition, during recording, the range from ○ gloss to 600 OE was divided into 16 parts, converted into digital signals, and PE modulated. It was recorded using the method.

The recording magnetic field data recorded in the first sector as a magneto-optical signal is reproduced under the same reproduction conditions as in Example 1, and stored in the memory built into the drive device. , the magnetic field applying electromagnet is driven by the recording magnetic field stored in the memory.

Furthermore, in order to confirm the effect, the same signal as in Example 1 was recorded and the same reproduction evaluation was performed, and as a result, the same results as in Example 17 were obtained.

Example 3 A disk similar to that shown in Example 1 was manufactured except that a TbFe film was used as the magnetic film and SiO was used as the protective film. Results 1. Linear velocity sm/sec, recording magnetic field 4o
As a result of finding the optimal recording power at 00e, 3.0 m
It was W. As a result of recording and reproducing using this disk in the same manner as in Example 1, recording was possible under optimal conditions and an error frequency of 1×1Q-5 was obtained.

As a result, it can be seen that a large improvement effect can be obtained even for disks with different structures.

In this embodiment, the portion where the recording conditions are recorded as data is provided at the outermost circumference of the disk, but the portion where the recording conditions are recorded as data may be at the innermost circumference or in the middle.

Effects of the Invention The present invention writes the recording conditions of each disk as data on a part of the disk, and sets the optimum recording conditions while referring to the data during recording. It is possible to maintain compatibility, and it is also possible to use a line recording method, which was previously impossible due to variations in recording sensitivity.
The present invention provides an excellent magneto-optical recording carrier that can realize approximately twice the recording density.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the structure of a magneto-optical record carrier according to an embodiment of the present invention, and FIG. 2 is a data state diagram showing the structure of an address sector of the magneto-optical record carrier. 1...Magneto-optical disk, 2...0 sector. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
1? -Q is also Asahi Den Wav

Claims (2)

[Claims] (1) A magneto-optical record carrier characterized in that an optimum recording laser power under standard recording conditions is recorded on a part of the record carrier capable of recording and reproducing. (2) A magneto-optical record carrier characterized in that an optimum recording magnetic field under standard recording conditions for the record carrier is recorded on a part of the record carrier capable of recording and reproducing.