Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
1999-11-10
2002-09-24
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Core
Reexamination Certificate
active
06456460
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of electronic data storage. In particular, the present invention relates to track width definition by patterning of shared poles for an integrated thin film/magnetoresistive head.
Thin film magnetic transducing heads are used for magnetically reading information from and writing information to a magnetic storage medium such as a magnetic disc or a magnetic tape. Transducing heads each include a reader portion and a writer portion. The reader portion, which includes a top shield, a bottom shield, and a magnetoresistive (MR) reader positioned between the top and the bottom shields, is used to read magnetically encoded information from the magnetic medium by detecting magnetic flux stored on the magnetic medium. The MR reader (which includes amorphous MR readers, giant MR readers, and spin tunneling readers) generally consists of various magnetic and nonmagnetic layers. The writer portion, which includes a top pole, a bottom pole, conductive coils positioned between the top and bottom poles, and a write gap between the top and bottom poles writes magnetic information to the storage medium. Typically, the top shield of the reader portion and the bottom pole of the writer portion are combined into a common shared pole.
During a write operation, the media moves past an air bearing surface of the writer portion of a transducing head, such that a particular portion of the media will first encounter a leading pole of the writer followed by a trailing pole. Magnetic transitions are produced by transducing head only when the applied field falls to media coercivity, i.e., all data is written by the trailing pole. Accordingly, the trailing pole defines the track width of the written data. In disc drive applications, the trailing pole is always the top pole, which is patterned to allow for a more narrow track width. In tape drive applications, in which the magnetic tape media moves bi-directionally, the trailing pole may be either the top pole or the shared pole.
Data are stored on magnetic tapes in parallel tracks that extend in the direction of the length of the magnetic tape. Historically, write-wide, read-narrow methodologies were sufficient to ensure that the read heads remained on-track during read-back. With increased data densities on magnetic tapes, new head assemblies were developed that moved across the width of the magnetic tape, such that each read and write head in the head assembly would have access to multiple data tracks. However, write-wide, read-narrow methodologies are no longer sufficient to ensure that these new assemblies remain on track. As a result, dual bump tape heads have been developed to limit tracking errors in these new assemblies.
Bi-directional, dual bump tape heads have two transducing heads and are capable of operating in a read while write (RWW) mode. In this RWW mode, a leading transducing head writes information to the tape, while a trailing transducing head reads information from the tape, either data or servo information to ensure that the dual bump tape head remains on track. Each transducing head, or “bump”, includes a writer portion having a top pole, a shared pole, conductive coils positioned between the top pole and the shared pole, and a flex circuit connected to the conductive coils.
The bumps within a dual bump tape head may be configured in a first configuration with the shared poles of both bumps being centrally located and the top poles of both bumps being peripherally located, such that the shared poles are sandwiched between the top poles (e.g., the reader portions of the two bumps are positioned back-to-back). Conversely, the bumps may be configured in a second configuration with the top poles centrally located and the shared poles peripherally located, such that the top poles are sandwiched between the shared poles (e.g., the writer portions of the two bumps are positioned back-to-back).
In the first configuration, the shared pole of the leading bump always writes; whereas in the second configuration, the top pole of the leading bump always writes. Accordingly, the second configuration results in a narrower track width than in the first configuration since the patterned top pole is narrower than the shared pole. However, in the second configuration, the flex circuits for the two bumps, which connect to the conductive coils of each bump, are located closer to one another than in the first configuration, resulting in a greater amount of cross-talk between bumps in the second configuration than in the first configuration.
There is therefore a need for a dual bump tape head which allows for a more narrow track width while minimizes cross-talk between bumps.
BRIEF SUMMARY OF THE INVENTION
A read while write dual bump tape head for increasing allowable linear and areal bit density comprises first and second thin-film inductive write heads. The first thin film, inductive write head has a first top pole and a first shared pole. The first shared pole is patterned such that it has a width at a tape bearing surface of the dual bump tape head narrower than a width of the first top pole at the tape bearing surface. The second thin-film inductive head has a second top pole and a second shared pole. The second shared pole is patterned such that it has a width at the tape bearing surface narrower than a width of the second top pole at the tape bearing surface.
REFERENCES:
patent: 4951166 (1990-08-01), Schewe
patent: 5121270 (1992-06-01), Alcudia et al.
patent: 5276579 (1994-01-01), Takamori
patent: 5505635 (1996-04-01), Das
patent: 5703740 (1997-12-01), Cohen et al.
Connolly Maura P.
Hutson David
Johnston Alan B.
Troutman Mark E.
Kinney & Lange , P.A.
Seagate Technology LLC
Tupper Robert S.
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