IP Library Granted Patent US 12,658,200
Granted Patent B2
US 12,658,200 · App. 18/740,048 · Granted Jun 16, 2026

Low friction planar servo writer head

Inventors: Robert G. Biskeborn (San Jose, CA); Oscar J. Ruiz (San Jose, CA); Trevor W. Olson (San Jose, CA)
Assignee: Western Digital Technologies, Inc.
G11B5/255G11B5/00813G11B5/1871G11B5/3106G11B5/3116G11B5/3183G11B15/64
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Quick Facts
Patent No.
US 12,658,200
App. No.
18/740,048
Granted
Jun 16, 2026
Kind
B2
Abstract

When servo heads in a head chip of a servo write head assembly record servo patterns onto a tape's servo tracks, the servo heads are continuously being rapidly worn away by the tape. This general wear affects the servo heads' ability to record the servo patterns, impairing accurate positioning of the tape heads in the drive. However, by implementing, on the leading edge of the head chip, a support block that has a wear resistant skiving edge and landing zone for the tape “crow bar,” which forms when the tape is running over the servo head, the general wear of the servo heads from the tape is mitigated. The skiving edge, which may be formed by thin film technology process steps, causes the tape to fly over the head chip in those regions. An additional support block may be implemented at the trailing edge of the head chip.

Claims (35)

1 . A device for writing servo patterns on a magnetic tape, comprising:

a head chip comprising one or more servo write heads;

a first film structure disposed on a media facing surface of the head chip, wherein a plurality of servo patterns of the one or more servo write heads are disposed on an outward facing surface of the first film structure;

at least one support block disposed adjacent to the head chip, the first film structure and the at least one support block forming a planar media facing surface, wherein the at least one support block is configured to entrain air between a tape traversing the planar media facing surface and the first film structure; and

a second film structure disposed on a bottom surface of the support block.

2 . The device for writing servo patterns on the magnetic tape of claim 1 , wherein the at least one support block comprises alumina titanium carbide (AlTiC).

3 . The device for writing servo patterns on the magnetic tape of claim 1 , wherein a skiving edge is formed into the at least one support block.

4 . The device for writing servo patterns on the magnetic tape of claim 3 , wherein a plurality of depressions are disposed along the skiving edge, and the plurality of depressions are configured to entrain air between the tape traversing the planar media facing surface and the first film structure.

5 . The device for writing servo patterns on the magnetic tape of claim 4 , wherein the plurality of depressions are disposed at intervals along the skiving edge based on the plurality of servo patterns.

6 . The device for writing servo patterns on the magnetic tape of claim 1 , wherein the first film structure has a thickness between 8 microns to 16 microns.

7 . The device for writing servo patterns on the magnetic tape of claim 1 , wherein the at least one support block is disposed at a leading edge of the head chip.

8 . The device for writing servo patterns on the magnetic tape of claim 1 , wherein an outward-facing surface of the second film structure is flush with a bottom surface of the head chip.

9 . The device for writing servo patterns on the magnetic tape of claim 1 , further comprising a second support block of the at least one support block, wherein the second support block is disposed on a trailing surface of the head chip, wherein each support block is disposed on opposing surfaces of the head chip.

10 . A servo write bar, comprising:

a head chip comprising one or more servo write heads;

a first film structure disposed on a media facing surface of the head chip, wherein a plurality of servo patterns of the one or more servo write heads are disposed on an outward-facing surface of the first film structure;

at least one support block disposed at a leading edge of the head chip, the first film structure and the at least one support block forming a planar media facing surface;

a skiving edge formed into the at least one support block; and

a second film structure disposed on a bottom surface of the support block.

11 . The servo write bar of claim 10 , wherein the first film structure comprises amorphous aluminum oxide (AIO) and the at least one support block comprises alumina titanium carbide (AlTiC).

12 . The servo write bar of claim 10 , wherein a plurality of depressions are disposed at equal intervals along the skiving edge, and the plurality of depressions are configured to entrain air between a tape traversing a planar media facing surface and the first film structure.

13 . The servo write bar of claim 12 , wherein the plurality of depressions are disposed along the skiving edge based on the plurality of servo patterns.

14 . The servo write bar of claim 12 , wherein the plurality of depressions are tapered or sloped in shape.

15 . The servo write bar of claim 12 , wherein a width of the plurality of depressions is between 20 microns and 100 microns.

16 . The servo write bar of claim 12 , wherein a height of the plurality of depressions is between 5 microns and 25 microns.

17 . The servo write bar of claim 10 , wherein an outward-facing surface of the second film structure is flush with a bottom surface of the head chip.

18 . A servo write bar, comprising:

means to write a servo pattern on a tape, comprising:

a first head chip comprising one or more servo write heads;

a first film disposed on a media facing surface of the first head chip, wherein a plurality of servo patterns of the one or more servo write heads are disposed on an outward-facing surface of the first film;

at least one support block disposed at a leading edge of the first head chip, the first film and the at least one support block forming a planar media facing surface;

wherein a second film is disposed on a bottom surface of the at least one support block opposing the planar media facing surface; and

a means for entraining air between a tape traversing the planar media facing surface and the first film.

19 . The servo write bar of claim 18 , wherein the means for entraining air is formed into the at least one support block.

20 . The servo write bar of claim 18 , wherein the at least one support block is a second head chip, and wherein the second film is disposed on the second head chip opposing the planar media facing surface.

Assignments (2)
PATENT COLLATERAL AGREEMENT (AR) Recorded Aug 23, 2024
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A., AS THE AGENT
Reel/Frame 068762/0695 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 12, 2024
From: BISKEBORN, ROBERT G.; RUIZ, OSCAR J.; OLSON, TREVOR W.
To: WESTERN DIGITAL TECHNOLOGIES., INC.
Reel/Frame 067700/0056 →
Continuity (1)
Related Publication 20250378846A1 · Dec 11, 2025
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