IP Library Granted Patent US 7,477,464
Granted Patent B2
US 7,477,464 · App. 11/507,243 · Granted Jan 13, 2009

Manufacturing method of recording medium, electric/magnetic field copy master and electric/magnetic field copying device

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Quick Facts
Patent No.
US 7,477,464
App. No.
11/507,243
Granted
Jan 13, 2009
Kind
B2
Abstract

When copying servo information from an electro-magnetic field copy master to a vertical storage medium, the magnetization direction of the vertical storage medium is made to the direction the reverse of an external electro-magnetic field applied to the vertical storage medium and the electro-magnetic field copymaster, the vertical storage medium is closely touched on the electromagnetic field copy master provided with a substrate which has concavity/convexity corresponding to the servo information and at least the convex part of which of the concavity/convexity is made of a softly magnetic material and a conductor installed in the concave part of the substrate and an external electro-magnetic field stronger than the coercive field strength of the vertical storage medium is instantaneously applied to the vertical storage medium and the electromagnetic field copy master.

Claims (28)

1. A method with a process of copying prescribed information from an electro-magnetic field copy master, for manufacturing a perpendicular magnetic record medium, the copying process comprising:

initializing a magnetization direction of the perpendicular magnetic record medium in a direction which is the reverse of a direction of an external electro-magnetic field;

closely touching or approaching the perpendicular magnetic record medium on or to the electro-magnetic field copy master provided with a substrate which has concavity and convexity corresponding to the prescribed information on the surface and at least the convex part of which of the concavity and convexity is made of a soft magnetic material, and a conductor is provided above a concave part of the substrate wherein a lower surface of the conductor and a lower surface of the soft magnetic film on the convex part are approximately in the same plane; and

instantaneously applying an external electro-magnetic field stronger than coercive field strength of the perpendicular magnetic record medium to the perpendicular magnetic record medium and the electro-magnetic field copy master.

2. The manufacturing method of a perpendicular magnetic record medium according to claim 1 , wherein

a rise speed of the external electro-magnetic field is 1 or more kOe/ms.

3. A perpendicular magnetic record medium to which prescribed information is copied by the manufacturing method of a perpendicular magnetic record medium according to claim 1 .

4. A magnetic disk device provided with a perpendicular magnetic record medium to which prescribed information is copied by the manufacturing method of the perpendicular magnetic record medium according to claim 1 .

5. The manufacturing method of a perpendicular magnetic storage medium according to claim 1 , wherein the soft magnetic material is formed inside the concave part and the conductor is formed directly on the soft magnetic material formed in the concave part.

6. An electro-magnetic field copy master used to copy prescribed information to a recording surface of a perpendicular magnetic record medium, comprising:

a substrate which has concavity and convexity corresponding to the prescribed information on a surface and at least the convex part of which of the concavity and convexity is made of a soft magnetic material; and

a conductor is provided above the concave part of the substrate, wherein a lower surface of the conductor and a lower surface of the soft magnetic film on the convex part are approximately in the same plane.

7. The electro-magnetic field copy master according to claim 6 , wherein

an electric resistivity ratio of the soft magnetic field to the conductor is one digit or more.

8. The electro-magnetic field copy master according to claim 6 , wherein

the conductor is made of copper, silver, aluminum or gold.

9. The electro-magnetic field copy master according to claim 6 , wherein

the soft magnetic material is made of FeCoNi in which grain boundary is deposited.

10. The electro-magnetic field copy master according to claim 6 , wherein the soft magnetic material is formed inside the concave part and the conductor is formed directly on the soft magnetic material formed in the concave part.

11. An electro-magnetic field copying device for copying prescribed information from an electro-magnetic field copy master to a perpendicular magnetic record medium by applying an external electro-magnetic field to the perpendicular magnetic record medium and the electro-magnetic field copy master in a direction perpendicular to a recording surface of the perpendicular magnetic record medium while the electro-magnetic field copy master is closely touched on or approached to the perpendicular magnetic record medium, comprising:

an electro-magnetic field copy master provided with a substrate which has concavity and convexity corresponding to the prescribed information on the surface and at least a convex part of which of the concavity and convexity is made of a soft magnetic material, a conductor is provided above a concave part of the substrate, wherein a lower surface of the conductor and a lower surface of the soft magnetic film on the convex part are approximately in the same plane;

an electro-magnet for generating the external electro-magnetic field; and

an electro-magnetic generation unit for flowing current through the electro-magnet to instantaneously generate the external electro-magnetic field stronger than coercive field strength of the perpendicular magnetic record medium in the electro-magnet.

12. The electro-magnetic field copying device according to claim 11 , wherein

an inductance of a coil constituting the electro-magnet is 10 mH or less.

13. The electro-magnetic field copying device according to claim 11 , wherein

the electro-magnetic field generation unit generates two or more external electro-magnetic fields, using one DC power supply.

14. The electro-magnetic field copying device according to claim 11 , wherein the soft magnetic material is formed inside the concave part and the conductor is formed directly on the soft magnetic material formed in the concave part.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 26, 2009
From: FUJITSU LIMITED
To: TOSHIBA STORAGE DEVICE CORPORATION
Reel/Frame 023861/0881 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 21, 2006
From: KURODA, SUMIO
To: FUJITSU LIMITED
Reel/Frame 018208/0640 →