Magnetic signal reproducing device, magnetic signal reproducing method and magnetic recording medium for high density reproduction

A magnetic signal reproducing device for reproducing information from a magnetic recording medium which is provided with a magnetic film having a magnetic compensation temperature and is formed such that a polarity of magnetization is inverted at the magnetic compensation temperature during temperature change, the device comprising:

• local temperature raising means for locally raising the temperature of the magnetic recording medium;
• reproducing means having a magnetized information detecting area for magnetically detecting information recorded on the magnetic recording medium, and
• during a reproducing operation, the local temperature raising means forms an area having a lower temperature than the magnetic compensation temperature and an area having a higher temperature than the magnetic compensation temperature within an area in the magnetic recording medium which area is facing the magnetized information detecting area and is other than a reproduction target area, thereby reducing contribution to reproduced signal from magnetization of the area other than the reproduction target area, wherein the magnetic recording medium is provided with a plurality of tracks for recording information, and
• the local temperature raising means forms an area having a lower temperature than the magnetic compensation temperature and an area having a higher temperature than the magnetic compensation temperature in tracks other than a reproduction target track within an area in the magnetic recording medium which area is facing the magnetized information detecting area.

A magnetic signal reproducing device for reproducing information from a magnetic recording medium which is provided with a plurality of tracks for recording information and a magnetic film having a magnetic compensation temperature and in which a polarity of magnetization is inverted at the magnetic compensation temperature during temperature change, the device comprising:

• local temperature raising means for irradiating the magnetic recording medium with a laser beam to locally raise the temperature of the magnetic recording medium;
• and
• reproducing means having a magnetized information detecting area for magnetically detecting magnetized information recorded on the magnetic recording medium, the reproducing means being so arranged that the center of the laser beam is almost coincident with the center of the magnetized information detecting area in a direction of a track width,
• wherein the magnetized information detecting area has a width at least partially facing three tracks of the magnetic recording medium in the direction of the track width, and
• during a reproducing operation, the local temperature raising means raises the temperature of a central track facing the magnetized information detecting area over the magnetic compensation temperature and raises the temperatures of two tracks adjacent to the central track such that an average temperature in each of the adjacent two tracks is almost equal to the magnetic compensation temperature, thereby reducing contribution to reproduced signal from magnetization of the two adjacent tracks.

A magnetic signal reproducing method comprising the steps of:

• using a magnetic recording medium in which the polarity of magnetized information is inverted at a first temperature during temperature change;
• locally raising the temperature of the magnetic recording medium by local temperature raising means;
• and
• magnetically detecting magnetized information recorded on the magnetic recording medium by reproducing means having a magnetized information detecting area facing at least a part of a portion having a temperature raised,
• wherein, during a reproducing operation, the temperature of the magnetic recording medium is raised such that an area having a lower temperature than the first temperature and an area having a higher temperature than the first temperature are formed within an area in the magnetic recording medium which area is other than a reproduction target area and is facing the magnetized information detecting area, and thereby contribution to reproduced signal from magnetization of the area other than the reproduction target area is reduced.

A magnetic signal reproducing method comprising the steps of:

• using a magnetic recording medium which is provided with a magnetic film having a magnetic compensation temperature and is formed such that the polarity of magnetized information is inverted at the magnetic compensation temperature during temperature change;
• locally raising the temperature of the magnetic recording medium by local temperature raising means;
• and
• magnetically detecting magnetized information recorded on the magnetic recording medium by reproducing means having a magnetized information detecting area facing at least a part of a portion having a temperature raised,
• wherein, during a reproducing operation, the temperature of the magnetic recording medium is raised such that an area having a lower temperature than the magnetic compensation temperature and an area having a higher temperature than the magnetic compensation temperature are formed within an area in the magnetic recording medium which area is other than a reproduction target area and is facing the magnetized information detecting area, and thereby contribution to reproduced signal from magnetization of the area other than the reproduction target area is reduced.

A magnetic signal reproducing method comprising the steps of:

• using a magnetic recording medium which is provided with a plurality of tracks for recording information and a magnetic film having a magnetic compensation temperature and in which the polarity of magnetized information is inverted at the magnetic compensation temperature during temperature change;
• locally raising the temperature of the magnetic recording medium by irradiation with a laser beam;
• and
• magnetically detecting magnetized information recorded on the magnetic recording medium by a magnetized information detecting area of reproducing means which area is facing at least a part of a portion having a temperature raised,
• wherein the magnetized information detecting area has a width at least partially facing three tracks of the magnetic recording medium in a direction of a track width,
• the reproducing means is so situated that the center of the laser beam is almost coincident with the center of the magnetized information detecting area in the direction of the track width, and
• during a reproducing operation, the temperature of the magnetic recording media is raised such that the temperature of a central track opposed to the magnetized information detecting area is over the magnetic compensation temperature and the average temperature in an area of each of two tracks adjacent to the central track which area is facing the magnetized information detecting area is almost equal to the magnetic compensation temperature, and thereby contribution to reproduced signal from magnetization of the two adjacent tracks is reduced.