JPH053044B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to a recording method of a magneto-optical recording device that records information on a thermal mode material using a light beam.
In particular, the present invention relates to a magneto-optical recording method in which recording is performed by rotating a recording medium at a constant angular velocity.

Prior Art In a magneto-optical recording device that uses a method (CAV rotation method) in which recording is performed by rotating a recording medium at a constant angular velocity, the optical energy density per unit area is significantly different between the outer track and the inner track. As a result, perpendicular magnetization pits are not formed faithfully according to the laser on or off signal.

That is, as shown in FIG. 1, in the CAV rotation method, the exposed area passing through the exposure time Δt becomes smaller from the outer circumference to the inner circumference of the recording medium 1.
The energy density of the pit recording area .DELTA.S1 on the outer track T1 will be smaller than the energy density of the pit recording area .DELTA.S2 on the inner track T2 unless appropriate compensation is provided.

Conventionally, the solution to this problem is to gradually reduce the recording laser power from the outer track to the inner track and record on the recording medium. A method for correcting recording pits has been proposed. Such laser power control is generally performed by monitoring the laser light, applying feedback control to the system, and adjusting the control target according to the radial position of the recording medium.

However, in the recording method of such a conventional magneto-optical recording device, the configuration of the control system is complicated, so the device itself has to be expensive, especially in a device using a laser diode.
The feedback gain varies depending on the wavelength and conversion efficiency of the laser diode, and therefore, there is a problem in that it is not possible to provide a device that can perform stable control at a low cost.

Purpose The present invention was made in view of such conventional problems, and its purpose is to control the strength of the auxiliary magnetic field formed during recording without changing the laser power. It is an object of the present invention to provide a magneto-optical recording method that allows stable recording over the entire surface.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings.

In magneto-optical recording, depending on the magneto-optical material used for the recording medium, the recording auxiliary magnetic field is an important element for forming recording pits along with the irradiated light beam.For example, for materials such as GaTbFe and GaTbCoFe, the recording pit area varies depending on the strength of the recording auxiliary magnetic field.

Therefore, we compensated for the lack of pit formation area due to insufficient energy density of the light beam at the outer periphery of the recording medium by increasing the strength of the recording auxiliary magnetic field, and gradually decreased the magnetic field strength toward the inner periphery. Therefore, a stable pit recording area can be formed over the entire surface of the recording medium. Here, if the strength of the recording auxiliary magnetic field is excessive, the perpendicular magnetization will be reversed regardless of the light beam, so the strength of the auxiliary magnetic field used is made sufficiently smaller than the strength of the magnetic field.

FIG. 2 shows an example of the configuration of a magneto-optical recording device for carrying out the method of the present invention, in which 1 is a recording medium, consisting of a substrate 1A and a magneto-optical thin film 1B provided on the substrate 1A, and a spindle. It is rotated by a motor 3 at a constant angular velocity. 4 is an optical recording head, which is disposed facing the magneto-optical thin film 1B;
A light beam is irradiated onto the magneto-optical thin film 1B. Reference numeral 5 designates an auxiliary magnetic field generator provided on the opposite side of the optical recording head 4 across the recording medium 1, and uses, for example, a DC coil. Reference numeral 6 denotes a motor that moves the optical recording head 4 and the auxiliary magnetic field generator 5 as a pair in the radial direction R of the recording medium 1 shown by the arrow. A head access controller 7 controls the positions of the optical recording head 4 and the auxiliary magnetic field generator 5. Also,
8 is a programmable DC variable power supply that drives the auxiliary magnetic field generator 4 to change the strength of the magnetic field under the control of the controller 7, for example.

To explain the recording operation of the magneto-optical recording device having such a configuration, first, the spindle motor 3 is activated so as to rotate the recording medium 1 at a constant angular velocity. When the recording medium 1 reaches the set rotational speed, the head access controller 7 operates the motor 6 to move the optical recording head 4 and the auxiliary magnetic field generator 5 toward the specified recording track position on the recording medium 1. . At the same time, the head access controller 7 gives a command to the power supply 8 to generate a magnetic field with a strength corresponding to the position of the auxiliary magnetic field generator 5 on the recording medium 1 in the radial direction.

That is, the optical recording head 4 and the auxiliary magnetic field generator 5 move as a pair in the R direction on the recording area of the recording medium 1 via the recording medium 1, and at this time, the auxiliary magnetic field generator 5 moves along the radius of the recording medium 1. The magnetic field strength is changed according to the position in the direction, and in cooperation with the recording light beam irradiated by the optical recording head 4, stable pit recording is performed over the entire surface of the recording medium 1.

Effects As explained above, according to the present invention, C.
In a magneto-optical recording device using the AV rotation method, the strength of the auxiliary magnetic field for recording is gradually decreased from the outer circumference to the inner circumference in the radial direction of the recording medium. The effect is that stable recording can be performed.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram illustrating the information recording area on a recording medium when magneto-optical recording is performed by the CAV rotation method, and Fig. 2 shows an example of the configuration of a magneto-optical recording device that implements the method of the present invention. It is a block diagram. Δt...exposure time, T1, T2...track,
ΔS1, ΔS2... Pit recording area, 1... Recording medium, 1A... Substrate, 1B... Magneto-optical thin film, 3...
Spindle motor, 4... Optical head, 5... Auxiliary magnetic field generator, 6... Motor, 7... Head access controller, 8... Power supply.

Claims (1)

[Claims] 1. Rotating a disk-shaped recording medium at a constant angular velocity,
In a magneto-optical recording method in which information is recorded magneto-optically by irradiating a light beam of constant intensity while applying a magnetic field to the recording medium, . A magneto-optical recording method, characterized in that the intensity of the applied magnetic field is reduced.