US Patent No: 8,228,627
Number of patents in Portfolio can not be more than 2000
Magnetic disk drive
Stats
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Jul 24, 2012
Issued date -
Dec 17, 2009
filing date -
12/641,157
serial no -
In Force
status
Importance
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Abstract
According to one embodiment, a magnetic disk drive includes a magnetic disk to be subjected to perpendicular recording, a first pole core including a main pole configured to record signals on the magnetic disk, a first coil wound around the first pole core, a second pole core magnetically independent of the first pole core, tip ends of which are arranged on both sides of the main pole, a second coil wound around the second pole core, a read unit including an element configured to read data recorded on the magnetic disk, and a correction unit configured to correct a current phase difference between the first and second coils.
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First Claim
Related Publications
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International Classification(s)
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Cited Art
| Patent Info | (Count) | # Cites | Year |
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| 2008/0273,268 PERPENDICULAR MAGNETIC RECORDING WRITE HEAD WITH COPLANAR MAIN POLE AND RETURN POLES AND MAGNETIC RECORDING SYSTEM | 9 | 2007 | |
| 2008/0075,977 Magnetic film, manufacturing method thereof and thin film magnetic head | 1 | 2007 | |
| 2009/0097,156 MAGNETIC RECORDING DISK AND DISK DRIVE WITH PATTERNED PHASE-TYPE SERVO FIELDS FOR READ/WRITE HEAD POSITIONING | 2 | 2007 | |
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| 5,396,391 Magnetic recording system providing a magnetic head having opposite sides for applying different magnetic field strengths to a magnetic recording medium | 16 | 1991 | |
| 7,791,829 Apparatus for assisting write operation using high frequency magnetic field in disk drive | 18 | 2008 | |
| 2010/0007,992 Magnetic head assembly and magnetic recording apparatus | 13 | 2009 | |
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| 6,710,972 Magnetic head for perpendicular recording and magnetic disk storage apparatus mounting the head | 14 | 2003 | |
| 7,180,704 Magnetic head for perpendicular recording and magnetic disk storage apparatus mounting the head | 8 | 2005 | |
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| 7,952,827 Heat-assisted magnetic recording method using eddy current and head for heat-assisted magnetic recording | 2 | 2007 | |
| 8,094,399 Magnetic recording apparatus provided with microwave-assisted head | 4 | 2010 | |
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| 2008/0218,902 METHOD FOR MEASURING WIDTH OF PLATING LAYER, MAGNETIC RECORDING HEAD, AND MANUFACTURING METHOD THEREOF | 3 | 2008 | |
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| 6,473,258 Magnetic disk read/write circuit having core coils of opposite phase | 7 | 2000 | |
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| 6,934,128 Magnetic head and magnetic disk drive | 4 | 2004 | |
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| 4,816,947 Single track vertical and horizontal recording read/write head design | 43 | 1987 | |
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| 2008/0165,452 Virtual front shield writer | 1 | 2007 | |
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| 4,703,382 Thin-film magnetic head for perpendicular (vertical) recording | 15 | 1984 | |
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| 4,317,148 Transducer for perpendicular magnetic recording | 35 | 1980 | |
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| 4,535,369 Magnetic recording and reproducing apparatus | 24 | 1983 | |
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| 6,038,093 Magnetic recording/reproducing apparatus with a current supplying circuit for demagnetizing residual magnetization remaining at an end of a magnetic pole | 11 | 1997 | |
Patent Citation Ranking
Maintenance Fees
| Fee | Large entity fee | small entity fee | micro entity fee | due date |
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| 3.5 Year Payment | $1600.00 | $800.00 | $400.00 | Jan 24, 2016 |
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| 11.5 Year Payment | $7400.00 | $3700.00 | $1850.00 | Jan 24, 2024 |
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