IP Library › Granted Patent US 7,648,620
Granted Patent B2
US 7,648,620 · App. 11/391,418 · Granted Jan 19, 2010

Method for manufacturing a master disk for magnetic transfer

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Quick Facts
Patent No.
US 7,648,620
App. No.
11/391,418
Granted
Jan 19, 2010
Kind
B2
Abstract

A method for manufacturing a master disk for magnetic transfer, comprising the steps of electroforming a master substrate of a metal disk with a surface on which an convexoconcave pattern corresponding to information to be transferred is transferred using a reverse die with a reversed convexoconcave pattern, and forming a magnetic layer on the convexoconcave pattern of the master substrate, the method comprising the steps of: a conductive layer forming step to form a conductive layer with a thickness t 1 on a surface of the reverse die; an initial electroforming step to form a first plated layer with a thickness t 2 equal to or more than the thickness t 1 of the conductive layer by plating a surface of the conductive layer at a current density of 0.35 A/dm 2 or less; and a main electroforming step to form a second plated layer by plating a surface of the first plated layer at a current density of 0.35 A/dm 2 or more.

Claims (36)

1. A method for manufacturing a master disk for magnetic transfer, comprising the steps of electroforming a master substrate of a metal disk with a surface on which an convexoconcave pattern corresponding to information to be transferred is transferred using a reverse die with a reversed convexoconcave pattern, and forming a magnetic layer on the convexoconcave pattern of the master substrate, the method comprising the steps of:

a conductive layer forming step to form a conductive layer with a thickness t 1 on a surface of the reverse die;

an initial electroforming step to form a first plated layer with a thickness t 2 equal to or more than the thickness t 1 of the conductive layer by plating a surface of the conductive layer at a current density of 0.35 A/dm 2 or less;

a main electroforming step to form a second plated layer with a thickness t 3 by plating a surface of the first plated layer at a current density of 15.3 A/dm 2 or more; and

a final electroforming step to form a third plated layer by plating a surface of the second plated layer at a current density of 5.2 A/dm 2 or less.

2. The method for manufacturing a master disk for magnetic transfer according to claim 1 , wherein the thickness t 1 of the conductive layer is 20 to 40 nm.

3. The method for manufacturing a master disk for magnetic transfer according to claim 1 , wherein the thickness t 2 of the first plated layer is one to one-half times of the thickness t 1 of the conductive layer.

4. The method for manufacturing a master disk for magnetic transfer according to claim 2 , wherein the thickness t 2 of the first plated layer is one to one-half times of the thickness t 1 of the conductive layer.

5. The method for manufacturing a master disk for magnetic transfer according to claim 1 , wherein the thickness t 3 of the second plated layer is 100 to 300 μm.

6. The method for manufacturing a master disk for magnetic transfer according to claim 2 , wherein the thickness t 3 of the second plated layer is 100 to 300 μm.

7. The method for manufacturing a master disk for magnetic transfer according to claim 3 , wherein the thickness t 3 of the second plated layer is 100 to 300 μm.

8. The method for manufacturing a master disk for magnetic transfer according to claim 4 , wherein the thickness t 3 of the second plated layer is 100 to 300 μm.

9. The method for manufacturing a master disk for magnetic transfer according to claim 1 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

10. The method for manufacturing a master disk for magnetic transfer according to claim 2 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

11. The method for manufacturing a master disk for magnetic transfer according to claim 3 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

12. The method for manufacturing a master disk for magnetic transfer according to claim 4 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

13. The method for manufacturing a master disk for magnetic transfer according to claim 5 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

14. The method for manufacturing a master disk for magnetic transfer according to claim 6 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

15. The method for manufacturing a master disk for magnetic transfer according to claim 7 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

16. The method for manufacturing a master disk for magnetic transfer according to claim 8 , wherein the first plated layer and/or the second plated layer is formed of a Ni-based metal.

17. The method for manufacturing a master disk for magnetic transfer according to claim 1 , wherein the conductive layer is formed by sputtering.

18. The method for manufacturing a master disk for magnetic transfer according to claim 2 , wherein the conductive layer is formed by sputtering.

19. The method for manufacturing a master disk for magnetic transfer according to claim 3 , wherein the conductive layer is formed by sputtering.

20. The method for manufacturing a master disk for magnetic transfer according to claim 4 , wherein the conductive layer is formed by sputtering.

21. The method for manufacturing a master disk for magnetic transfer according to claim 5 , wherein the conductive layer is formed by sputtering.

22. The method for manufacturing a master disk for magnetic transfer according to claim 6 , wherein the conductive layer is formed by sputtering.

23. The method for manufacturing a master disk for magnetic transfer according to claim 7 , wherein the conductive layer is formed by sputtering.

24. The method for manufacturing a master disk for magnetic transfer according to claim 8 , wherein the conductive layer is formed by sputtering.

25. The method for manufacturing a master disk for magnetic transfer according to claim 9 , wherein the conductive layer is formed by sputtering.

26. The method for manufacturing a master disk for magnetic transfer according to claim 10 , wherein the conductive layer is formed by sputtering.

27. The method for manufacturing a master disk for magnetic transfer according to claim 11 , wherein the conductive layer is formed by sputtering.

28. The method for manufacturing a master disk for magnetic transfer according to claim 12 , wherein the conductive layer is formed by sputtering.

29. The method for manufacturing a master disk for magnetic transfer according to claim 13 , wherein the conductive layer is formed by sputtering.

30. The method for manufacturing a master disk for magnetic transfer according to claim 14 , wherein the conductive layer is formed by sputtering.

31. The method for manufacturing a master disk for magnetic transfer according to claim 15 , wherein the conductive layer is formed by sputtering.

32. The method for manufacturing a master disk for magnetic transfer according to claim 16 , wherein the conductive layer is formed by sputtering.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 15, 2007
From: FUJIFILM HOLDINGS CORPORATION (FORMERLY FUJI PHOTO FILM CO., LTD.)
To: FUJIFILM CORPORATION
Reel/Frame 018904/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 29, 2006
From: CHE, YANLONG
To: FUJI PHOTO FILM CO., LD.
Reel/Frame 017747/0406 →