IP Library Granted Patent US 7,489,462
Granted Patent B2
US 7,489,462 · App. 11/397,655 · Granted Feb 10, 2009

Master medium and magnetic recording medium

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Quick Facts
Patent No.
US 7,489,462
App. No.
11/397,655
Granted
Feb 10, 2009
Kind
B2
Abstract

A master medium has a servo pattern to be transferred onto a magnetic recording medium. The servo pattern includes a magnetically stable pattern that is easily transferred onto the magnetic recoding medium and that is magnetically stable.

Claims (43)

1. A master medium having a servo pattern to be transferred onto a magnetic recording medium, wherein the servo pattern is formed with

a first bit including a pair of first sub-bits sequentially arranged; and

a second bit including a pair of a first sub-bit and a second sub-bit sequentially arranged, and

each of the first sub-bit and the second sub-bit is a magnetic unit having a polarity,

the first sub-bit and the second sub-bit have different polarities, and

when the first bit is arranged in succession, at least one of continuous first bits is replaced with the second bit.

2. The master medium according to claim 1 , wherein

when the second bit is arranged with a shift of one sub-bit along a borderline of adjacent tracks of the magnetic recording medium, one of adjacent second bits is replaced with the first bit or a pair of the second sub-bits sequentially arranged.

3. A master medium having a servo pattern to be transferred onto a magnetic recording medium, wherein

the servo pattern has a plurality of oblique lines oppositely arranged across a boundary line, and

the plurality of oblique lines include:

first lines having a first angle with respect to the boundary line and a second angle with respect to a tangent of a track of the master medium; and

second lines having a third angle different from the first angle with respect to the boundary line and the same second angle with respect to the tangent.

4. A master medium having a servo pattern to be transferred onto a magnetic recording medium, wherein

the servo pattern is formed with

a first bit including a pair of a first sub-bit and a second sub-bit sequentially arranged; and

a second bit including a pair of a third sub-bit and a fourth sub-bit sequentially arranged,

each of the first sub-bit, the second sub-bit, the third sub-bit, and the fourth sub-bit is a magnetic unit having a polarity,

the first sub-bit and the fourth sub-bit have a first polarity,

the second sub-bit and the third sub-bit have a second polarity that is different from the first polarity, and

when the first bit and the second bit on adjacent tracks of the magnetic recording medium have a neighboring pattern corner in which the first sub-bit and the fourth sub-bit are arranged to make a diagonal contact or the second sub-bit and the third sub-bit are arranged to make a diagonal contact, either one of the first bit and the second bit is replaced with a pair of the first sub-bits sequentially arranged or a pair of the second sub-bits sequentially arranged.

5. A magnetic recording medium onto which a servo pattern of a master medium is transferred, wherein

the servo pattern is formed with

a first bit including a pair of first sub-bits sequentially arranged; and

a second bit including a pair of a first sub-bit and a second sub-bit sequentially arranged,

each of the first sub-bit and the second sub-bit is a magnetic unit having a polarity,

the first sub-bit and the second sub-bit have different polarities, and

when the first bit is arranged in succession, at least one of continuous first bits is replaced with the second bit.

6. The magnetic recording medium according to claim 5 , wherein

when the second bit is arranged with a shift of one sub-bit along a borderline of adjacent tracks of the magnetic recording medium, one of adjacent second bits is replaced with the first bit or a pair of the second sub-bits sequentially arranged.

7. A magnetic recording medium onto which a servo pattern of a master medium is transferred, wherein

the servo pattern has a plurality of oblique lines oppositely arranged across a boundary line, and

the plurality of oblique lines include:

first lines having a first angle with respect to the boundary line and a second angle with respect to a tangent of a track of the master medium; and

second lines having a third angle different from the first angle with respect to the boundary line and the same second angle with respect to the tangent.

8. A magnetic recording medium onto which a servo pattern of a master medium is transferred, wherein

the servo pattern is formed with

a first bit including a pair of a first sub-bit and a second sub-bit sequentially arranged; and

a second bit including a pair of a third sub-bit and a fourth sub-bit sequentially arranged,

each of the first sub-bit, the second sub-bit, the third sub-bit, and the fourth sub-bit is a magnetic unit having a polarity,

the first sub-bit and the fourth sub-bit have a first polarity,

the second sub-bit and the third sub-bit have a second polarity that is different from the first polarity, and

when the first bit and the second bit on adjacent tracks of the magnetic recording medium have a neighboring pattern corner in which the first sub-bit and the fourth sub-bit are arranged to make a diagonal contact or the second sub-bit and the third sub-bit are arranged to make a diagonal contact, either one of the first bit and the second bit is replaced with a pair of the first sub-bits sequentially arranged or a pair of the second sub-bits sequentially arranged.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 23, 2009
From: FUJITSU LIMITED
To: TOSHIBA STORAGE DEVICE CORPORATION
Reel/Frame 023558/0225 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 4, 2006
From: NAKAMURA, YUTAKA
To: FUJITSU LIMITED
Reel/Frame 017757/0473 →