MAGNETIC TRANSFER METHOD AND MASTER MANUFACTURING METHOD
A magnetic transfer method includes arranging a magnetic transfer master so as to cause a surface of the magnetic transfer master to be in proximity to or in contact with a vertical magnetic recording medium. The magnetic transfer master has on the surface thereof a concave-convex pattern representing information. A top surface of a convex portion of the concave-convex pattern is divided by a plurality of projecting threads lined up and extending at an interval shorter than a shortest pattern length of the concave-convex pattern. The magnetic transfer method includes applying a magnetic field to the magnetic transfer master in a direction along the surface and intersecting the projecting threads.
1 . A magnetic transfer method comprising:
arranging a magnetic transfer master so as to cause a surface of the magnetic transfer master to be in proximity to or in contact with a vertical magnetic recording medium, the magnetic transfer master having on the surface thereof a concave-convex pattern representing information, a top surface of a convex portion of the concave-convex pattern being divided by a plurality of projecting threads lined up and extending at an interval shorter than a shortest pattern length of the concave-convex pattern; and
applying a magnetic field to the magnetic transfer master in a direction along the surface and intersecting the projecting threads.
2 . The magnetic transfer method according to claim 1 , wherein the concave-convex pattern is a pattern in which concaves and convexes are alternately lined up along a predetermined line, and
the projecting thread extends in a direction intersecting the predetermined line.
3 . The magnetic transfer method according to claim 1 , wherein the projecting threads are lined up at an interval equal to or less than one-fourth of the shortest pattern length of the concave-convex pattern.
4 . The magnetic transfer method according to claim 1 , wherein the projecting thread has a width equal to or more than an average particle diameter of a crystal particle diameter of the vertical magnetic recording medium, and the projecting threads are lined up at an interval equal to or more than the average particle diameter.
5 . A master manufacturing method for manufacturing a magnetic transfer master having on a surface thereof a concave-convex pattern representing information, the magnetic transfer master transferring the information represented by the concave-convex pattern onto a magnetic recording medium as a magnetic pattern by causing the surface to be in proximity to or in contact with the vertical magnetic recording medium with an application of a magnetic field, the master manufacturing method comprising:
forming the concave-convex pattern on a substrate that is to be a basis of the magnetic transfer master; and
before or after the pattern formation, dividing a surface of the substrate into a plurality of projecting threads lined up and extending at an interval shorter than a shortest pattern length of the concave-convex pattern, by forming a plurality of grooves on all over the surface with a stencil mask, the grooves extending in a direction intersecting a direction of the magnetic field.
6 . The master manufacturing method according to claim 5 , wherein the concave-convex pattern is a pattern in which concaves and convexes are alternately lined up along a predetermined line, and
the projecting thread extends in a direction intersecting the predetermined line.
7 . The master manufacturing method according to claim 5 , wherein the projecting threads are lined up at an interval equal to or less than one-fourth of the shortest pattern length of the concave-convex pattern.
8 . The master manufacturing method according to claim 5 , wherein the projecting thread has a width equal to or more than an average particle diameter of a crystal particle diameter of the vertical magnetic recording medium, and the projecting threads are lined up at an interval equal to or more than the average particle diameter.
9 . An information reproduction apparatus for reproducing control information and arbitrary information from a vertical magnetic recording medium having the arbitrary information recorded as a magnetic pattern under a control based on the control information, the vertical magnetic recording medium having the control information recorded as the magnetic pattern trough a magnetic transfer method including: arranging a magnetic transfer master so as to cause a surface of the magnetic transfer master to be in proximity to or in contact with the vertical magnetic recording medium, the magnetic transfer master having on the surface thereof a concave-convex pattern representing information, a top surface of a convex portion of the concave-convex pattern being divided by a plurality of projecting threads lined up and extending at an interval shorter than a shortest pattern length of the concave-convex pattern; and applying a magnetic field to the magnetic transfer master in a direction along the surface and intersecting the projecting threads, the information reproduction apparatus comprising:
a pattern reading section that reads the magnetic pattern from the vertical magnetic recording medium to obtain a read signal causing a signal reversal according to a magnetization reversal in the magnetic pattern;
a peak holding section that holds a peak of the read signal obtained from the magnetic pattern of the control information among the read signals obtained by the pattern reading section; and
an information reproduction section that reproduces the control information and the arbitrary information by performing a signal processing on the read signal obtained by the pattern reading section from the magnetic pattern of the arbitrary information and the read signal whose peak is held by the peak holding section, the control information and the arbitrary information being reproduced from the read signals.
10 . The information reproduction apparatus according to claim 9 , wherein the concave-convex pattern is a pattern in which concaves and convexes are alternately lined up along a predetermined line, and
the projecting thread extends in a direction intersecting the predetermined line.
11 . The information reproduction apparatus according to claim 9 , wherein the projecting threads are lined up at an interval equal to or less than one-fourth of the shortest pattern length of the concave-convex pattern.
12 . The information reproduction apparatus according to claim 9 , wherein the projecting thread has a width equal to or more than an average particle diameter of a crystal particle diameter of the vertical magnetic recording medium, and the projecting threads are lined up at an interval equal to or more than the average particle diameter.