Amplitude servo pattern, magnetic recording medium and the manufacturing method, patterned magnetic transfer master substrate used in the manufacturing method, and magnetic recording/reproducing apparatus
View Patent ↗An amplitude servo pattern capable of providing accurate servo control through reproduced amplitude with reduced noise is provided. The amplitude servo pattern has servo burst signals composed of burst bit strings adjacently disposed in a track width direction. The burst bit strings are disposed such that the servo burst signals adjacently disposed in the track width direction have a phase difference with each other in a track direction.
1. A magnetic recording medium having an amplitude servo pattern recorded on the magnetic recording layer of the medium through magnetic transfer,
wherein the amplitude servo pattern has servo burst signals composed of burst bit strings adjacently disposed in a track width direction, and the servo burst signals adjacently disposed in the track width direction have different phases with each other in a track direction;
wherein the ratio of the length in the track width direction to the track direction of each bit in the burst bit strings is not greater than 2; and
wherein the length of the bit in the track width direction is longer than the track pitch.
2. The magnetic recording medium according to claim 1 , wherein the servo burst signals adjacently disposed in the track width direction have a phase difference in the range from 90 to 180 degrees.
3. The magnetic recording medium according to claim 1 ,
wherein each of the servo burst signals has rounded edges in the track width direction.
4. The magnetic recording medium according to claim 1 , wherein the track pitch is less than 200 nm.
5. The magnetic recording medium according to claim 1 , wherein the servo burst signal is inclined relative to the track width direction.
6. The magnetic recording medium according to claim 1 , wherein the servo burst signal has a parallelogram shape.
7. The magnetic recording medium according to claim 6 , wherein the parallelogram shape is inclined relative to the track width direction.
8. A manufacturing method for manufacturing a preformatted magnetic recording medium, comprising the steps of:
placing the surface of a patterned magnetic transfer master substrate and a magnetic recording surface of a magnetic recording medium together in close contact with each other, the master substrate having thereon an amplitude servo transfer pattern that comprises servo burst signals composed of burst bit element strings adjacently disposed in a track width direction, and the servo burst signals adjacently disposed in the track width direction having different phases with each other in a track direction, wherein the ratio of the length in the track width direction to the track direction of each bit in the burst bit element strings is not greater than 2 and wherein the length of the bit in the track width direction is longer than the track pitch; and
applying a magnetic field to the closely contacted patterned magnetic transfer master substrate and magnetic recording medium to magnetically transfer the amplitude servo transfer pattern to the recording surface of the magnetic recording medium.
9. A patterned magnetic transfer master substrate having thereon an amplitude servo transfer pattern that comprises servo burst signals composed of burst bit strings adjacently disposed in a track width direction, the servo burst signals adjacently disposed in the track width direction having different phases with each other in a track direction, wherein the ratio of the length in the track width direction to the track direction of each bit in the burst bit strings is not greater than 2 and wherein the length of the bit in the track width direction is longer than the track pitch.
10. The patterned magnetic transfer master substrate according to claim 9 , wherein the servo burst signals adjacently disposed in the track width direction have a phase difference in the range from 90 to 180 degrees.
11. The patterned magnetic transfer master substrate according to claim 9 ,
wherein each of the servo burst signals has rounded edges in the track width direction.
12. A magnetic recording/reproducing apparatus, comprising:
a magnetic head;
a preformatted magnetic recording medium disposed opposite to the magnetic head;
a means for driving the magnetic head;
a means for driving the magnetic medium; and
a recording/reproduced signal processing means for processing signals before sending to or after receiving from the magnetic head,
wherein the preformat of the magnetic medium includes an amplitude servo pattern that comprises servo burst signals composed of burst bit strings adjacently disposed in a track width direction, the servo burst signals adjacently disposed in the track width direction having different phases with each other in a track direction, wherein the ratio of the length in the track width direction to the track direction of each bit in the burst bit strings is not greater than 2 and wherein the length of the bit in the track width direction is longer than the track pitch.