Dynamic magnetic information storage or retrieval – Head – Head surface structure
Reexamination Certificate
2000-09-19
2004-08-03
Klimowicz, William (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Head surface structure
Reexamination Certificate
active
06771462
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is a perpendicular recording head for use with magnetic storage media. The perpendicular recording head has a tip with a concave surface for concentrating the magnetic flux over a smaller portion of the magnetic storage medium's surface area than current perpendicular recording heads.
2. Description of the Related Art
Although other perpendicular recording heads have been developed, the present invention improves upon presently known perpendicular recording heads by utilizing a concave cavity to focus magnetic flux, or being dimensioned and configured to focus magnetic flux at a distance approximating the flying height of the recording head.
An example of a magnetic recording head is described in U.S. Pat. No. 4,078,300, issued to J. P. Lazzari on Mar. 14, 1978. This patent describes a method of making a magnetic recording head intended to work in conjunction with a track of a magnetic storage medium having a narrow width.
U.S. Pat. No. 4,138,702, issued to J. G. Magnenet on Feb. 6, 1979, describes a head arrangement for perpendicular recording on a magnetic record carrier. The head arrangement has an electromagnet with a core and a magnetic shunt on opposite sides of the magnetic recording medium.
U.S. Pat. No. 4,546,398, issued to J. Toda et al. on Oct. 8, 1985, describes a perpendicular recording head. The perpendicular recording head includes a main pole made from a thin magnetic film, and a spiral coil electromagnetically coupled to the main pole.
U.S. Pat. No. 4,652,956, issued to H. Schewe on Mar. 24, 1987, describes a recording head for perpendicular magnetization. The recording head has a pair of magnetic legs forming a ring-shaped member, and separate read and write wire coils. The read coil is located between the two magnetic legs, and the write coil is located outside one of the two magnetic legs.
U.S. Pat. No. 4,731,157, issued to J. P. Lazzari on Mar. 15, 1988, describes a process for making a perpendicular recording head. The process includes the steps of depositing magnetic film on an insulating substrate, etching a channel in the magnetic film for containing a coil within a dielectric material, etching another channel in the dielectric layer for containing a second magnetic film, removing dielectric material to expose the lateral edge of the second magnetic film, and depositing additional dielectric material on top of the second magnetic film.
U.S. Pat. No. 4,943,882, issued to T. Wada et al. on Jul. 24, 1990, describes a perpendicular recording head. The recording head includes a first main pole surrounded by a conductor coil, with an insulator covering the first main pole and coil. The first main pole is in contact with a magnetic substrate at its top end. A second main pole is in contact with the first main pole. This assembly is covered with a protective overcoat. A similar recording head is described in U.S. Pat. No. 5,225,953, also issued to T. Wada et al. on Jul. 6, 1993.
U.S. Pat. No. 4,974,110, issued to M. Kanamine et al. on Nov. 27, 1990, describes a perpendicular recording head having a main magnetic pole, a spiral coil surrounding the main pole, and a pair of auxiliary magnetic poles on either side of the main pole. The magnetic flux from the resulting two magnetic leakage paths and the coil cancel each other out, thereby reducing edge noise.
U.S. Pat. No. 4,985,792, issued to M. B. Boir on Jan. 15, 1991, and assigned to the assignee of the present inventors, describes an improved spindle motor for a fixed disk drive for a computer.
U.S. Pat. No. 5,035,396, issued to R. G. Krum et al. on Jul. 30, 1991, and assigned to the assignee of the present inventors, describes a disk drive having a sealed disk drive housing, a common chassis for the disk drive and printed circuit board, and a floating bushing connecting the circuit board to the disk drive housing.
U.S. Pat. No. 5,073,836, issued to H. S. Gill et al. on Dec. 17, 1991, describes a perpendicular recording head. The primary magnetic pole is separated from the auxiliary pole by a distance sufficient to increase the reluctance of the recording head, thereby minimizing erasure of data within the recording medium.
U.S. Pat. No. 5,241,430, issued to D. W. Janz on Aug. 31, 1993, and assigned to the assignee of the present inventors, describes a disk drive which accepts write operations during manufacture, but only accepts read operations in use. The drive's controller responds to power supply voltage levels available to the user's computer by performing only read operations, but will perform a write operation in response to a higher voltage.
U.S. Pat. No. 5,430,589, issued to M. B. Moir et al. on Jul. 4, 1995, and assigned to the assignee of the present inventors, describes a disk drive having a vibration-absorbing insulator between the housing and the shaft for the storage disks.
U.S. Pat. No. 5,486,967, issued to Y. Tanaka et al. on Jan. 23, 1996, describes a perpendicular recording head having a pair of main poles, and which is in contact with the magnetic disk during use.
U.S. Pat. No. 5,738,927, issued to A. Nakamura et al. on Apr. 14, 1998, describes a perpendicular magnetic recording medium having a substrate and a film having perpendicular magnetic anisotropy formed over the substrate. A protective film covers the magnetic film.
U.S. Pat. No. 5,796,557, issued to G. N. Bagnell et al. on Aug. 18, 1998, and assigned to the assignee of the present inventors, describes a disk drive including six storage disks and fitting within a 3.5 inch, half height port.
U.S. Pat. No. 5,996,045, issued to L. Lee et al. on Nov. 30, 1999, and assigned to the assignee of the present inventors, describes a disk drive arrangement combining a master drive and a slave drive. Both drives use the same IDE bus. The host computer is able to send commands over the IDS bus in the same manner as if only one disk drive was present, and the command is then carried out by the appropriate drive.
The article, Sakhrat K. Khizroev, James A. Bain, and Mark H. Kryder, “Considerations in the design of Probe Heads for 100 Gbit/in
2
Recording Density,”
IEEE Transactions on Magnetics
(September, 1997) pp. 2893-2895, describes work performed by two inventors of the present invention towards development of giant magnetoresistive read heads capable of reading magnetic storage media having high storage densities.
The article, Jon William Toigo, “Avoiding a Data Crunch,”
Scientific American
(May, 2000) pp. 58-74, describes several approaches to increasing the information storage density within fixed computer drives.
None of the above described patents and publications describes a perpendicular recording head for use with magnetic recording media having a concave cavity at its tip for concentrating the magnetic flux within the storage layer of the magnetic storage medium. Additionally, none of the above patents and publications describes a recording head permitting the recording densities possible with the present invention.
SUMMARY OF THE INVENTION
The present invention is a perpendicular recording head for use with magnetic recording media having a main pole with a tip having a concave surface. The concave surface concentrates magnetic flux from the main pole to a higher density than a conventional perpendicular recording head at a distance approximating the flying height of the head, thereby permitting a greater amount of information to be stored on the magnetic recording medium. Although not limited to such use, a perpendicular recording head of the present invention is particularly useful for fixed (also known as hard) computer disk drives.
A typical perpendicular recording head includes a main pole, an opposing pole magnetically coupled to the main pole, and an electrically conductive wire coil surrounding the main pole. The bottom of the opposing pole will typically have a surface area greatly exceeding the surface area of the main pole's tip. Electrical current flowing through the coil creates a flux through the main pole. The direction of the
Khizroev Sakhrat
Kryder Mark H.
Litvinov Dmitri
Klimowicz William
Pietragallo Bosick & Gordon
Seagate Technology LLC
Towner, Esq. Alan G.
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