Magneto-optical recording device for improving C/N ratio
AssigneeSharp Kabushiki Kaisha
InventorsAkira Takahashi, Yoshiteru Murakami, Kenji Ohta
Life of this patent
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Abstract
A magneto-optical recording device having a light source and external magnetic field applying apparatus, which records information on a magneto-optical recording medium with a magnetic field modulation method. The device has a controller which stops the irradiation of a light beam when switching the direction of applying external magnetic field during recording. This allows an area where information is recorded with a low external magnetic field to be smaller, and thereby achieving reproduced signal of improved quality.
Claims9
A magneto-optical recording device comprising
- a recording medium made of a rare-earth transition-metal composition wherein the ratio of the transition metal to the rare earth is greater than the ratio thereof for rare-earth-transition-metal compositions in which the compensation temperature thereof is equal to room temperature;
- a light source for irradiating a light beam on said recording medium;
- external magnetic field applying means for recording information on the recording medium by applying an external magnetic field to an area on the recording medium, the direction of the magnetic field varying in accordance with the information to be recorded and the temperature of the area being raised with the irradiation of the light beam;
- and
- control means for detecting when said external magnetic field applying means is instructed to switch directions, and, when such detection is made, controlling said light source to stop irradiating the light beam for a time period before said external magnetic field applying means switches the direction of applying the external magnetic field.
A method for recording information on a recording medium with the use of a magneto-optical recording device having a light source for irradiating a light beam on the recording medium and external magnetic field applying means for recording information on the recording medium by applying an external magnetic field on an area of the recording medium, the temperature of the recording medium being raised with the irradiation of the light beam, comprising the steps of:
- using a recording medium made of a rare-earth-transition-metal composition wherein the ratio of the transition metal to the rare earth is greater than the ratio thereof for rare-earth-transition metal compositions in which the compensation temperature thereof is equal to room temperature;
- irradiating the light beam on the recording medium by said light source;
- applying the external magnetic field to the recording medium;
- switching a direction of applying the external magnetic field;
- detecting when said external magnetic field applying means is instructed to switch the direction of applying the external magnetic field;
- and
- when such detection is made, stopping the irradiation of the light beam for a time period before said external magnetic field applying means switches the direction of applying the external magnetic field.
A method for recording information on a recording medium with the use of a magneto-optical recording device having a light source for irradiating a light beam on the recording medium and external magnetic field applying means for recording information on the recording medium by applying an external magnetic field on an area of the recording medium, the temperature of the recording medium being raised with the irradiation of the light beam, comprising the steps of:
- using a recording medium made of a rare-earth-transition-metal composition wherein the ratio of the transition metal to the rare earth is greater than the ratio thereof for rare-earth-transition metal compositions in which the compensation temperature thereof is equal to room temperature;,
- irradiating the light beam on the recording medium by said light source;
- applying the external magnetic field to the recording medium;
- switching a direction of applying the external magnetic field;
- and
- stopping the irradiation of the light beam when switching the direction of applying the external magnetic field;
- wherein the material of said recording medium is Dy.sub.0.21 (Fe.sub.0.78 Co.sub.0.22).sub.0.79.
Dependencies are inferred from the claim text.