| 序号 | 专利名 | 申请号 | 申请日 | 公开（公告）号 | 公开（公告）日 | 发明人 |
|---|---|---|---|---|---|---|
| 61 | Reset of magnetic domains in write head via magnetic field from media | US14976184 | 2015-12-21 | US09595275B1 | 2017-03-14 | Yanzhang Liu; Kirill Rivkin; Lei Lu; Huaqing Yin |
| A method of removing a magnetic domain from a slider structure, such as a shield of a write head, in a storage assembly having a storage media. The method includes passing the slider structure in close proximity to a region on the storage media having a magnetic field sufficiently large to remove a magnetic domain in the slider structure. | ||||||
| 62 | Reset of magnetic domains in write head via external field | US14976286 | 2015-12-21 | US09520148B1 | 2016-12-13 | Yanzhang Liu; Kirill Rivkin; Lei Lu; Huaqing Yin |
| Methods of removing a magnetic domain from a slider structure, such as a shield in a write head, in a data storage assembly. The method comprises passing the slider structure in close proximity to a decaying magnetic field of at least 100 Oe and no more than 1500 Oe originating from within the storage assembly. In some implementations the decaying magnetic field has an oscillating polarity. | ||||||
| 63 | Magnetization control for magnetic shield in magnetic recording head | US14227933 | 2014-03-27 | US09263086B2 | 2016-02-16 | Satoshi Tabata; Norifumi Miyamoto; Akira Morinaga; Masahiro Ito; Masahiko Hatatani |
| A hard disk drive (HDD) is described which includes a magnetic field-generating device in the vicinity of a load/unload ramp such that the write head moves into a magnetic field generated by the device while the head is being unloaded from disk, whereby the magnetic field pins in a predominant direction the direction of magnetization of a magnetic shield associated with the write head, and away from the direction toward the disk. Recording magnetic field leakage associated with the shield is thereby suppressed and corresponding far track interference is inhibited. | ||||||
| 64 | Storage device having degauss circuitry configured for generating degauss signal with asymmetric decay envelopes | US13873355 | 2013-04-30 | US08873188B2 | 2014-10-28 | Boris Livshitz; Paul Mazur; Anamul Hoque; Jason S. Goldberg |
| A hard disk drive or other storage device comprises a storage medium, a write head configured to write data to the storage medium, and control circuitry coupled to the write head. The control circuitry comprises degauss circuitry coupled to or otherwise associated with one or more write drivers. The degauss circuitry is configured to generate an asymmetric degauss signal to be applied to the write head. The asymmetric degauss signal has a waveform with upper and lower decay envelopes that are asymmetric about a specified degauss current level, such as a substantially zero current level. | ||||||
| 65 | STORAGE DEVICE HAVING DEGAUSS CIRCUITRY GENERATING DEGAUSS SIGNAL WITH MULTIPLE DECAY SEGMENTS | US13606279 | 2012-09-07 | US20140071561A1 | 2014-03-13 | Boris Livshitz; Paul Mazur; Anamul Hoque |
| A hard disk drive or other disk-based storage device comprises a storage disk, a write head configured to write data to the disk, and control circuitry coupled to the write head. The control circuitry comprises a write driver and degauss circuitry associated with the write driver. The degauss circuitry is configured to generate a degauss signal to be applied to the write head by the write driver. The degauss signal has a waveform comprising a plurality of decay segments including at least one alternating current decay segment and at least one direct current decay segment. An initial decay segment of the plurality of decay segments may comprise an alternating current decay segment or a direct current decay segment, and may be immediately followed by a decay segment of the opposite type. | ||||||
| 66 | STORAGE DEVICE HAVING DEGAUSS CIRCUITRY WITH SEPARATE CONTROL OF DEGAUSS SIGNAL STEADY STATE AND OVERSHOOT PORTIONS | US13447741 | 2012-04-16 | US20130271867A1 | 2013-10-17 | Boris Livshitz; Anamul Hoque; Jason S. Goldberg |
| A hard disk drive or other disk-based storage device comprises a storage disk, a write head configured to write data to the disk, and control circuitry coupled to the write head. The control circuitry comprises a write driver and degauss circuitry associated with the write driver. The degauss circuitry is configured to control a degauss signal waveform to be applied to the write head by the write driver, and comprises separate amplitude envelope control mechanisms for steady state and overshoot portions of the degauss signal waveform. The separate amplitude envelope control mechanisms may comprise, for example, separate steady state and overshoot controllers for controlling the amplitude envelope decay rates of the respective steady state and overshoot portions of the degauss signal waveform over the plurality of pulses. | ||||||
| 67 | Degauss control for magnetic disk-drive preamplifier | US12120525 | 2008-05-14 | US07813068B2 | 2010-10-12 | Toru Takeuchi |
| One embodiment of the invention includes a preamplifier system for a magnetic disk-drive. The system includes a current distributor configured to generate a reference current and to decay the reference current from a first magnitude to a second magnitude during a degauss period to degauss a magnetic disk write head. The degauss period defines a transition from a write cycle to a read cycle of the magnetic disk-drive and has a predetermined time duration that is independent of the first magnitude of the reference current during the write cycle. An output driver is configured to provide a write current to the magnetic disk write head having a magnitude with an absolute value that is based on the reference current. | ||||||
| 68 | Head amplifier circuit with function for degaussing residual magnetism of recording head | US11215020 | 2005-08-31 | US07460324B2 | 2008-12-02 | Yusuke Ohinata; Hiroyuki Naka; Yuji Sakai |
| In a data-recording mode, a driver circuit supplies a recording head with a recording current corresponding to write data. In a degaussing mode, the driver circuit supplies the recording head with a degaussing current for eliminating the residual magnetism of the head as the recording current. The degaussing current has a rising period and falling period set longer than those of the recording current supplied in the data-recording mode. | ||||||
| 69 | Method for recording bursts on a disk and related apparatus | US11593494 | 2006-11-07 | US07450328B2 | 2008-11-11 | Won-choul Yang |
| Embodiments of the invention provide a method for recording bursts on a disk and a related apparatus. In accordance with an embodiment of the invention, a method for recording bursts on a burst field of a servo sector of a disk comprises generating a first write current corresponding to burst data provided by a write channel circuit, and generating a second write current having a higher frequency than the first write current using a high frequency AC current generator, wherein the high frequency AC current generator is independent from the write channel circuit. The method further comprises selectively applying the first write current to a write head in response to a signal and selectively applying the second write current to the write head in response to the signal. | ||||||
| 70 | Method and apparatus for magnetization test of write head in a disk drive | US11200163 | 2005-08-10 | US07411753B2 | 2008-08-12 | Yuji Sakai |
| A disk drive of a perpendicular magnetic recording system has a magnetization test function, for testing the magnetized state of a write head. The disk drive is provided with a write driver and a head amplifier unit. The write driver supplies a write current to the write head, for perpendicular magnetic recording. The degaussing unit degausses the write head. | ||||||
| 71 | Degaussing for write head | US11323065 | 2005-12-30 | US20070153410A1 | 2007-07-05 | Motomu Hashizume; Takashi Hirosawa |
| A write head degaussing circuit and methodology configured to end the degaussing signal a selectable percentage short of the tapered degaussing waveform, starting the degaussing of the write head current Iw at a percentage less than Iw, removing any overshoot of the degaussing signal, and any combination of the above. | ||||||
| 72 | Demagnetizing a head in a disk drive by increasing the frequency of an AC write signal while maintaining the write current amplitude | US10996116 | 2004-11-23 | US07092186B1 | 2006-08-15 | Dennis W. Hogg |
| A disk drive is disclosed which demagnetizes the head after a write operation. Write circuitry applies a write signal to the head in order to write data to a selected data sector during a write operation, wherein the write signal comprises a predetermined write current amplitude. Control circuitry demagnetizes the head at the end of the write operation by maintaining the write current amplitude while increasing a frequency of an AC write signal applied to the head over a predetermined demagnetization interval, wherein increasing the frequency of the AC write signal decreases an amplitude of the AC write signal when observed at the head. | ||||||
| 73 | Degauss waveform generator for perpendicular recording write head | US11331805 | 2006-01-13 | US20060158764A1 | 2006-07-20 | Hiroaki Suzuki; Kenji Okada |
| Embodiments of the invention provide a hard disk drive that is capable of performing degaussing promptly and properly and a recording method for use with such a hard disk drive. A hard disk drive according to one embodiment of the present invention comprises a current source for supplying a first current, which flows to a write head for writing data onto a magnetic disk; a current source for supplying a second current, which flows to the write head when the polarity of the first current changes; transistors for reversing the polarity of a current flowing to the write head; and a control circuit for exercising control so that the second current I2, which flows from the current source to the write head when the polarity of the first current I1 is reversed, becomes approximately zero before the first current I1 converges to approximately zero during a degauss period. | ||||||
| 74 | Head amplifier circuit with function for degaussing residual magnetism of recording head | US11215020 | 2005-08-31 | US20060139787A1 | 2006-06-29 | Yusuke Ohinata; Hiroyuki Naka; Yuji Sakai |
| In a data-recording mode, a driver circuit supplies a recording head with a recording current corresponding to write data. In a degaussing mode, the driver circuit supplies the recording head with a degaussing current for eliminating the residual magnetism of the head as the recording current. The degaussing current has a rising period and falling period set longer than those of the recording current supplied in the data-recording mode. | ||||||
| 75 | Thin laminated single pole perpendicular write head | US10610036 | 2003-06-30 | US07064924B2 | 2006-06-20 | Kochan Ju; Lijie Guan; Jeiwei Chang; Min Li; Ben Hu |
| Single write poles tend to large shape anisotropy which results in a very large remnant field when not actually writing. This has now been eliminated by giving the write pole the form of a three layer laminate in which two ferromagnetic layers are separated by a non-magnetic or antiferromagnetic coupling layer. Strong magnetostatic coupling between the outer layers causes their magnetization directions to automatically be antiparallel to one another, unless overcome by the more powerful write field, leaving the structure with a low net magnetic moment. The thickness of the middle layer must be carefully controlled. | ||||||
| 76 | Magnetic head and magnetic storage apparatus | US10354989 | 2003-01-31 | US07054106B2 | 2006-05-30 | Kazue Kudo; Yoshiaki Kawato; Kazuhiro Nakamoto; Nobuo Yoshida; Kimitoshi Etoh |
| Disclosed herein is a magnetic head for perpendicular recording in which the main magnetic pole has reduced remanent magnetization and is less liable to cause erasure after recording. These characteristic properties were realized by constructing the magnetic head such that the recording magnetic pole and the yoke are separate from each other and the main magnetic pole is formed from a material with a high saturation magnetic flux density and the yoke is formed from a material having a negative magnetostriction constant. | ||||||
| 77 | Method and apparatus for magnetization test of write head in a disk drive | US11200163 | 2005-08-10 | US20060044659A1 | 2006-03-02 | Yuji Sakai |
| A disk drive of a perpendicular magnetic recording system has a magnetization test function, for testing the magnetized state of a write head. The disk drive is provided with a write driver and a head amplifier unit. The write driver supplies a write current to the write head, for perpendicular magnetic recording. The degaussing unit degausses the write head. | ||||||
| 78 | Method and apparatus for read error recovery in a disk drive with a GMR read head | US10800972 | 2004-03-16 | US06975474B2 | 2005-12-13 | Hiroyuki Naka |
| A disk drive is disclosed which has a facility to perform a pinning reset operation on a GMR read element included in a head if a read retry operation fails to achieve recovery from a read error. When a bias and write currents are supplied to the head, a CPU of the disk drive determines an optimum bias and write currents on the basis of a temperature measured value of the GMR read element. | ||||||
| 79 | Method and apparatus for read error recovery in a disk drive with a GMR read head | US10800972 | 2004-03-16 | US20040212909A1 | 2004-10-28 | Hiroyuki Naka |
| A disk drive is disclosed which has a facility to perform a pinning reset operation on a GMR read element included in a head if a read retry operation fails to achieve recovery from a read error. When a bias and write currents are supplied to the head, a CPU of the disk drive determines an optimum bias and write currents on the basis of a temperature measured value of the GMR read element. | ||||||
| 80 | Method and apparatus for performing spin valve combined pinned layer reset and hard bias initialization at the HGA level | US09531618 | 2000-03-21 | US06728055B1 | 2004-04-27 | Hardayal Singh Gill; Christopher Dana Keener; Gautam Ratilal Patel |
| The present invention provides a method and apparatus for performing automated spin valve combined pinned layer reset and hard bias initialization at the head gimbal assembly level. The reset combines a current pulse with an assisting magnetic field. The pinned layer reset and hard bias initialization is automated and performed by a single tool at the head gimbal assembly level to increase manufacturing throughput. | ||||||
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