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公开(公告)号：US20250007238A1
公开(公告)日：2025-01-02
申请号：US18447552
申请日：2023-08-10
Applicant: Western Digital Technologies, Inc.
Inventor： Sukumar Rajauria , Erhard Schreck
Abstract: A data storage device may include one or more disks, an actuator arm assembly comprising one or more magnetic recording heads, at least one laser diode, and one or more processing devices configured to: set the at least one laser diode to a first temperature; apply a first forward bias and supply a first current to the at least one laser diode such that it is in a lasing state; measure, for the at least one laser diode, a first output corresponding to the first temperature and current; set the at least one laser diode to a second temperature; measure, for the at least one laser diode, a second output corresponding to the second temperature and the first current; and determine an output profile for the at least one laser diode, based at least in part on the respective output at the first temperature and the second temperature.
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公开(公告)号：US11934687B2
公开(公告)日：2024-03-19
申请号：US17743386
申请日：2022-05-12
Applicant: Western Digital Technologies, Inc.
Inventor： Erhard Schreck , Sukumar Rajauria , Robert Smith
IPC: G06F3/06
CPC classification number: G06F3/0655 , G06F3/0604 , G06F3/0676
Abstract: The present disclosure generally relates to a multi-disk drive comprising a plurality of media surfaces and a plurality of heads, wherein a head of the plurality of heads is configured to be actuated over each surface of the plurality of media surfaces. The multi-disk drive further comprises control circuitry configured to write data to a first media surface of the plurality of media surfaces using a first head of the plurality of heads, and after all of an available memory of the first media surface has been filled, write data to a second media surface of the plurality of media surfaces using a second head of the plurality of heads. The control circuitry is further configured to permanently disable write access to one or more media surfaces of the plurality of media surfaces, while continuing to permit read access to the plurality of media surfaces.
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公开(公告)号：US11694722B1
公开(公告)日：2023-07-04
申请号：US17651100
申请日：2022-02-15
Applicant: Western Digital Technologies, Inc.
Inventor： Shaomin Xiong , Erhard Schreck , Robert Smith , Sukumar Rajauria
CPC classification number: G11B21/106
Abstract: The present disclosure generally relates to using a data timestamp and/or a read counter to prevent data from being re-read and signal that the data has been accessed. The write assist element in the write head can be utilized to degrade the data or an allocated marker after the data has been read. The degradation functions as a read counter to indicate how many times the data has been read. Additionally and/or alternatively, a timestamp can be utilized. The timestamp is updated each time that the data has been accessed. In so doing, it is possible to determine whether data in a data storage device has been accessed.
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公开(公告)号：US11423939B1
公开(公告)日：2022-08-23
申请号：US17176302
申请日：2021-02-16
Applicant: Western Digital Technologies, Inc.
Inventor： Pierre-Olivier Jubert , Sukumar Rajauria
Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media, wherein the head comprises a write coil and a write pole. A test pattern is written to the magnetic media by applying a first current to the write coil. A second current is applied to the write coil while the head passes over the test pattern, wherein the second current has a polarity opposite the first current. After applying the second current to the write coil while the head passes over the test pattern, the test pattern is read from the magnetic media using the head to generate a first read signal, and a first noise power of the first read signal is measured. A degradation of the write pole is detected based on the first noise power measurement.
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5.发明授权公开(公告)号：US10950266B1
公开(公告)日：2021-03-16
申请号：US16805414
申请日：2020-02-28
Applicant: Western Digital Technologies, Inc.
Inventor： Sukumar Rajauria , Yuichi Aoki , Yukio Kato , Kosuke Nagase , Kiyoshi Hashimoto , Qing Dai
Abstract: The present disclosure relates to pretreating a magnetic recording head to increase the lifetime of the magnetic media drive. A transparent smear is purposefully formed on the magnetic recording head to ensure the magnetic recording head does not overheat and lead to a short drive lifetime. The transparent smear is formed from material found in the magnetic media. The transparent smear is formed by pretreating the magnetic recording head with the transparent material from the magnetic media. The pretreating occurs without writing any data to the magnetic media. Once the transparent smear is in place, writing may occur. The magnetic recording head can be retreated at a later time should the transparent smear degrade. Furthermore, if an optically absorbing smear develop, it can be removed and a new transparent smear may be formed.
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Patent Agency Ranking
6.发明授权公开(公告)号：US10910007B1
公开(公告)日：2021-02-02
申请号：US16791238
申请日：2020-02-14
Applicant: Western Digital Technologies, Inc.
Inventor： Tan Trinh , Sukumar Rajauria , Yuichi Aoki , Kosuke Nagase , Erhard Schreck , Qing Dai
Abstract: A heat-assisted magnetic recording (HAMR) hard disk drive has a gas-bearing slider supporting a near-field transducer (NFT) and a NFT temperature sensor (NTS). An optional first IVC circuitry may provide a bias voltage to the slider body to assure substantially zero electrical potential between the slider body and the disk to minimize slider-disk contact and lubrication pick-up. A second IVC circuitry operates independently of the first IVC circuitry and provides a negative bias voltage to the NTS (and the connected NFT) relative to the disk to minimize the adverse effects of excessive heating on the NFT.
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公开(公告)号：US11881230B2
公开(公告)日：2024-01-23
申请号：US17448170
申请日：2021-09-20
Applicant: Western Digital Technologies, Inc.
Inventor： Sukumar Rajauria , Oscar Ruiz , Erhard Schreck
CPC classification number: G11B13/08 , G11B5/4866 , G11B5/6088 , G11B7/126 , G11B2005/0021
Abstract: The present disclosure relates to pretreating a magnetic recording head. For a HAMR head, a NFT is present. Current can be applied to the NFT to condition the NFT. The current is applied in one of three ways: slowly ramping up the current from a starting level below a level capable of writing data to the optical laser current over a predetermined period of time, applying the current at a fixed value below the optical laser current for the predetermined period of time, or slowly ramping up the current from a starting level below a level capable of writing data to the optical laser current over the predetermined period of time while also intermittently removing the current. By conditioning the NFT in such a manner, the HAMR head can avoid thermal shock and thermal fatigue and thus increase the lifetime of the magnetic media drive.
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公开(公告)号：US11783854B1
公开(公告)日：2023-10-10
申请号：US17804490
申请日：2022-05-27
Applicant: WESTERN DIGITAL TECHNOLOGIES, INC.
Inventor： Sukumar Rajauria , Robert Lee Smith
CPC classification number: G11B5/40 , G11B5/56 , G11B33/144
Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; a head, configured to be positioned proximate to a disk surface among the one or more disks; a temperature sensor; and one or more processing devices. The one or more processing devices are configured to: detect, via the temperature sensor, a non-nominal heat dissipation of a portion of the head; and, in response to detecting the non-nominal heat dissipation of the portion of the head, mitigate the non-nominal heat dissipation of the portion of the head.
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9.发明授权公开(公告)号：US11257525B1
公开(公告)日：2022-02-22
申请号：US17176282
申请日：2021-02-16
Applicant: Western Digital Technologies, Inc.
Inventor： Sukumar Rajauria , Pierre-Olivier Jubert , Richard M. Brockie
Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media, wherein the head comprises a laser and a near field transducer (NFT). A thermal gradient produced in the magnetic media by the NFT is periodically measured, and a failure of the NFT is predicted based on a slope of the thermal gradient measurements.
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公开(公告)号：US11170814B1
公开(公告)日：2021-11-09
申请号：US16911064
申请日：2020-06-24
Applicant: Western Digital Technologies, Inc.
Inventor： Sukumar Rajauria , Oscar Ruiz , Erhard Schreck
Abstract: The present disclosure relates to pretreating a magnetic recording head. For a HAMR head, a NFT is present. Current can be applied to the NFT to condition the NFT. The current is applied in one of three ways: slowly ramping up the current from a starting level below a level capable of writing data to the optical laser current over a predetermined period of time, applying the current at a fixed value below the optical laser current for the predetermined period of time, or slowly ramping up the current from a starting level below a level capable of writing data to the optical laser current over the predetermined period of time while also intermittently removing the current. By conditioning the NFT in such a manner, the HAMR head can avoid thermal shock and thermal fatigue and thus increase the lifetime of the magnetic media drive.
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