IP Library › Granted Patent US 11,676,630
Granted Patent B1
US 11,676,630 · App. 17/651,117 · Granted Jun 13, 2023

Servo writer head design for the rotated servo pattern

Inventors: Satoshi Yamamoto (San Jose, CA); Masahito Kobayashi (Fujisawa, JP)
Assignee: Western Digital Technologies, Inc.
G11B5/584G11B5/4893
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Quick Facts
Patent No.
US 11,676,630
App. No.
17/651,117
Granted
Jun 13, 2023
Kind
B1
Abstract

The present disclosure is generally related to a servo track writer (STW) head for writing a rotated servo pattern. The STW head comprises a first writer stripe having a first length tilted at a first angle and a second writer stripe having a second length tilted at a second angle. The STW head may be tilted at a non-perpendicular angle relative to the edge of a tape configured to pass under the STW head.

Claims (32)

1. A servo track writer (STW) head, comprising:

a first writer stripe tilted at a first angle, wherein the first writer stripe has a first stripe length; and

a second writer stripe tilted at a second angle, wherein the second writer stripe has a second stripe length different than the first stripe length, wherein a first central axis of the second writer stripe is shifted in a direction parallel to a direction of tape movement.

2. The STW head of claim 1 ,

wherein the first writer stripe has a first stripe height, and

wherein the second writer stripe has a second stripe height substantially equal to the first stripe height.

3. The STW head of claim 2 , wherein the first stripe height is between about 70 micrometers and 80 micrometers, and wherein a stripe width is between about 1 micrometers and 2 micrometers.

4. The STW head of claim 1 , wherein the first angle and the second angle are tilted away from a second central axis between the first writer stripe and the second writer stripe, and wherein the first angle and the second angle are different.

5. The STW head of claim 4 , wherein the first angle is between about 15 degrees and 20 degrees, and wherein the second angle is between about −10 degrees and −5 degrees.

6. The STW head of claim 4 , wherein the first stripe length is greater than the second stripe length.

7. The STW head of claim 1 , wherein a distance between a first top point of the first writer stripe and a second top point of the second writer stripe is equal to (n−1)s+t+g, wherein n is a number of stripes, s is a stripe pattern spacing, t is a stripe pattern width, and g is a burst pattern gap.

8. A servo pattern writer comprising the STW head of claim 1 .

9. A servo track writer (STW) head, comprising:

a first writer stripe tilted at a first angle, the first writer stripe having a first stripe length; and

a second writer stripe tilted at a second angle, the second writer stripe having a second stripe length different than the first stripe length, wherein a distance between a first top point of the first writer stripe and a second top point of the second writer stripe is equal to (n−1)s+t+g, wherein n is a number of stripes, s is a stripe pattern spacing, t is a stripe pattern width, and g is a burst pattern gap.

10. The STW head of claim 9 ,

wherein the first writer stripe has a first stripe height, and

wherein the second writer stripe has a second stripe height substantially equal to the first stripe height.

11. The STW head of claim 10 , wherein the first stripe height and the second stripe height are each individually between about 70 micrometers and 80 micrometers.

12. The STW head of claim 9 , wherein the first angle and the second angle are tilted away from a central axis, and wherein the first angle and the second angle are different.

13. The STW head of claim 12 , wherein the first angle is between about 15 degrees and 20 degrees, and wherein the second angle is between about −10 degrees and −5 degrees.

14. A servo pattern writer comprising the STW head of claim 9 .

15. A servo track writer (STW) head, comprising:

a plurality of writer stripe pairs, each writer stripe pair comprising:

a first writer stripe tilted at a first angle, the first writer stripe having a first stripe length; and

a second writer stripe tilted at a second angle, the second writer stripe having a second stripe length different than the first stripe length,

wherein a distance between a first top point of the first writer stripe and a second top point of the second writer stripe is equal for each writer stripe pair.

16. The STW head of claim 15 , wherein a first central axis of the second writer stripe is shifted in a direction parallel to a direction of tape movement to maintain the equal distance between the first top point of the first writer stripe and the second top point of the second writer stripe for each writer stripe pair.

17. The STW head of claim 15 , wherein the first angle and the second angle are tilted away from a second central axis between the first writer stripe and the second writer stripe, and wherein the first angle and the second angle are different.

18. The STW head of claim 17 , wherein the first angle is between about 15 degrees and 20 degrees, wherein the second angle is between about −10 degrees and −5 degrees, and wherein the first stripe length is greater than the second stripe length.

19. The STW head of claim 15 , wherein the distance between the first top point of the first writer stripe and the second top point of the second writer stripe is equal to (n−1)s+t+g, wherein n is a number of stripes, s is a stripe pattern spacing, t is a stripe pattern width, and g is a burst pattern gap.

20. A servo pattern writer comprising the STW head of claim 15 .

Assignments (3)
PATENT COLLATERAL AGREEMENT - A&R LOAN AGREEMENT Recorded Aug 21, 2023
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 064715/0001 →
PATENT COLLATERAL AGREEMENT - DDTL LOAN AGREEMENT Recorded Aug 21, 2023
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 067045/0156 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 15, 2022
From: YAMAMOTO, SATOSHI; KOBAYASHI, MASAHITO
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 059014/0565 →