Patents by Inventor Kowang Liu
Kowang Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20250078862Abstract: The present embodiments can generally provide a magnetic write head structure with optimized gap current distribution to maximize the current-assisted areal density capacity (ADC) gain in hard-disk-drive storage devices. In a first example embodiment, a non-dual-write-shield (nDWS) write head can include a main pole (MP), a trailing shield (TS), and a write gap (WG) disposed between the MP and the TS. The write head can also include a side shield (SS), a leading shield (LS), and a write shield (WS). The write head can include a side gap (SG) between the MP and the SS on both sides of the MP tip, and a leading gap (LG) between the MP and the LS. The write head can also include a coil wrapped around the MP through a PP3 shield that is configured to direct a time-dependent write current to saturate magnetization of the MP.Type: ApplicationFiled: September 6, 2024Publication date: March 6, 2025Inventors: Shehrin Sayed, Wenyu Chen, Yue Liu, Kowang Liu, Tetsuya Roppongi, Haowen Ren, Yuhui Tang, Moris Musa Dovek, Wenjie Chen
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Publication number: 20240363140Abstract: The present embodiments relate to a perpendicular magnetic recording (PMR) write head with an STO element and configured to direct an electric current between elements of the write head. A first example embodiment describes a perpendicular magnetic recording (PMR) write head. The PMR write head can include a main pole comprising a tip portion disposed adjacent to an air bearing surface (ABS) and is configured to interact with a magnetic recording medium. The PMR write head can also include a spin torque oscillator (STO) element disposed adjacent to the main pole. The PMR write head can also include a side shield layer with a portion of the side shield layer disposed adjacent to the ABS. The PMR write head can also include a metallic side gap layer disposed between the main pole and the side shield layer.Type: ApplicationFiled: July 10, 2024Publication date: October 31, 2024Inventors: Kei Hirata, Kowang Liu, Yue Liu, Jiun-Ting Lee, Weihao Xu
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Patent number: 12094497Abstract: The present embodiments can generally provide a magnetic write head structure with optimized gap current distribution to maximize the current-assisted areal density capacity (ADC) gain in hard-disk-drive storage devices. In a first example embodiment, a non-dual-write-shield (nDWS) write head can include a main pole (MP), a trailing shield (TS), and a write gap (WG) disposed between the MP and the TS. The write head can also include a side shield (SS), a leading shield (LS), and a write shield (WS). The write head can include a side gap (SG) between the MP and the SS on both sides of the MP tip, and a leading gap (LG) between the MP and the LS. The write head can also include a coil wrapped around the MP through a PP3 shield that is configured to direct a time-dependent write current to saturate magnetization of the MP.Type: GrantFiled: August 30, 2023Date of Patent: September 17, 2024Assignee: Headway Technologies, Inc.Inventors: Shehrin Sayed, Wenyu Chen, Yue Liu, Kowang Liu, Tetsuya Roppongi, Haowen Ren, Yuhui Tang, Moris Musa Dovek, Wenjie Chen
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Patent number: 12073857Abstract: The present embodiments relate to a perpendicular magnetic recording (PMR) write head with an STO element and configured to direct an electric current between elements of the write head. A first example embodiment describes a perpendicular magnetic recording (PMR) write head. The PMR write head can include a main pole comprising a tip portion disposed adjacent to an air bearing surface (ABS) and is configured to interact with a magnetic recording medium. The PMR write head can also include a spin torque oscillator (STO) element disposed adjacent to the main pole. The PMR write head can also include a side shield layer with a portion of the side shield layer disposed adjacent to the ABS. The PMR write head can also include a metallic side gap layer disposed between the main pole and the side shield layer.Type: GrantFiled: February 15, 2023Date of Patent: August 27, 2024Assignee: Headway Technologies, Inc.Inventors: Kei Hirata, Kowang Liu, Yue Liu, Jiun-Ting Lee, Weihao Xu
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Publication number: 20240274152Abstract: The present embodiments relate to a perpendicular magnetic recording (PMR) write head with an STO element and configured to direct an electric current between elements of the write head. A first example embodiment describes a perpendicular magnetic recording (PMR) write head. The PMR write head can include a main pole comprising a tip portion disposed adjacent to an air bearing surface (ABS) and is configured to interact with a magnetic recording medium. The PMR write head can also include a spin torque oscillator (STO) element disposed adjacent to the main pole. The PMR write head can also include a side shield layer with a portion of the side shield layer disposed adjacent to the ABS. The PMR write head can also include a metallic side gap layer disposed between the main pole and the side shield layer.Type: ApplicationFiled: February 15, 2023Publication date: August 15, 2024Inventors: Kei Hirata, Kowang Liu, Yue Liu, Jiun-Ting Lee, Weihao Xu
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Patent number: 11973310Abstract: A light source unit for thermally-assisted magnetic head includes a substrate member having a first bonding surface; a light source assembly attached on the first bonding surface of the substrate member and having a second bonding surface; and a heater circuit assembly formed between the substrate member and the light source assembly, the heater circuit assembly having a heater formed on the substrate member and two leads connected at two ends of the heater, the lead being thicker than the heater, thereby a distance between the heater and the second bonding surface is farther than that between the lead and the second bonding surface. The light source unit can reduce mechanical stress and thermal conduction between a light source assembly and a substrate member, thereby improving the performance of the light source assembly and the heater.Type: GrantFiled: July 9, 2019Date of Patent: April 30, 2024Assignees: SAE MAGNETICS (H.K.) LTD., HEADWAY TECHNOLOGIES, INC.Inventors: Takashi Honda, Kowang Liu, Kwun Pan Ng, Makoto Kawato
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Patent number: 11289116Abstract: A PMR, TAMR or MAMR (Perpendicular Magnetic Recording, Thermally Assisted Magnetic Recording or Microwave Assisted Magnetic Recording) slider-mounted read/write head produces less heat during operation by using magnetic read shields in which are embedded a patterned layer of thermally absorbing material. At least one shield includes a heating coil which is used to adjust the fly-height of the slider by creating a thermal protrusion at the slider ABS. When additional sources of energy, such as laser heating, microwave heating or the write coil itself, are applied to the recording medium, the shields can overheat, adversely affecting their performance. The patterned layer of heat absorbing material reduces the flow of heat from the thermal heating coil to the air bearing surface (ABS) thus cooling the region around the write head while not adversely affecting the shape of the thermal protrusion.Type: GrantFiled: November 20, 2020Date of Patent: March 29, 2022Assignee: Headway Technologies, Inc.Inventors: Kowang Liu, Yuhui Tang, Siu Yin Ngan, Qinghua Zeng, Ellis Cha
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Patent number: 11211084Abstract: A Perpendicular Magnetic Recording (PMR) head is configured for use in Thermally Assisted Magnetic Recording (TAMR). Two or three contiguous write shields, of various widths and thicknesses, formed on a leading edge side of the write gap (WG), main pole (MP) and near-field transducer (NFT), protect the head during write touchdowns (TD) and signal the approach of such a touchdown. Moreover during a write touchdown the contact with the head is restricted to the large write shields, producing a large touchdown area (TDA) and insuring the lifetime of the head.Type: GrantFiled: October 16, 2020Date of Patent: December 28, 2021Assignees: SAE Magnetics (H.K.) Ltd., Headway Technologies, Inc.Inventors: Qinghua Zeng, Siu Yin Ngan, Ellis Cha, Kowang Liu
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Publication number: 20210013695Abstract: A light source unit for thermally-assisted magnetic head includes a substrate member having a first bonding surface; a light source assembly attached on the first bonding surface of the substrate member and having a second bonding surface; and a heater circuit assembly formed between the substrate member and the light source assembly, the heater circuit assembly having a heater formed on the substrate member and two leads connected at two ends of the heater, the lead being thicker than the heater, thereby a distance between the heater and the second bonding surface is farther than that between the lead and the second bonding surface. The light source unit can reduce mechanical stress and thermal conduction between a light source assembly and a substrate member, thereby improving the performance of the light source assembly and the heater.Type: ApplicationFiled: July 9, 2019Publication date: January 14, 2021Inventors: Takashi HONDA, Kowang LIU, Kwun Pan NG, Makoto KAWATO
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Patent number: 10811034Abstract: A microwave-assisted magnetic recording writer is disclosed wherein a heat sink is formed in a write gap (WG) and adjacent to a spin torque oscillator (STO) formed between a main pole (MP) trailing side and a trailing shield (hot seed layer). The WG comprises an electrically insulating layer with thickness of 5-80 Angstroms on the MP trailing side and STO sides. The heat sink layer may be separate coplanar layers on each STO side, or a single layer wrapping around the STO. A Ru or Cu heat sink has sufficient thermal conductivity to reduce STO temperature rise by 11% and 20%, respectively. Accordingly, the STO has longer lifetime at the same bias current density, or higher buffer head voltage is possible while maintaining STO device reliability. Each heat sink has a front side at an air bearing surface, and a stripe height (SH)?to the STO SH.Type: GrantFiled: April 1, 2019Date of Patent: October 20, 2020Assignee: Headway Technologies, Inc.Inventors: Yan Wu, Kowang Liu
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Publication number: 20200312354Abstract: A microwave-assisted magnetic recording writer is disclosed wherein a heat sink is formed in a write gap (WG) and adjacent to a spin torque oscillator (STO) formed between a main pole (MP) trailing side and a trailing shield (hot seed layer). The WG comprises an electrically insulating layer with thickness of 5-80 Angstroms on the MP trailing side and STO sides and the heat sink layer with a thickness that may be independently optimized and a width from 0.05 micron to 1 micron. A Ru or Cu heat sink has sufficient thermal conductivity to reduce STO temperature rise by 11% and 20%, respectively. Accordingly, the STO has longer lifetime at the same bias current density, or higher buffer head voltage is possible while maintaining STO device reliability. Each heat sink has a front side at an air bearing surface, and a stripe height (SH)?to the STO SH.Type: ApplicationFiled: April 1, 2019Publication date: October 1, 2020Inventors: Yan Wu, Kowang Liu
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Patent number: 10629233Abstract: A PMR read/write head configured for thermally assisted recording (TAMR) includes thermally active bumper pads formed to each side of a write element to provide enhanced touchdown (TD) protection to the write head element where it emerges adjacent to the plasmon near-field spot produced by the TAMR apparatus. The bumper pads are disposed about the write head and absorb heat energy generated by active heating elements, the write current and the energy generated by the TAMR apparatus. Absorption of this energy causes the bumper pads to expand and protrude outward from the slider ABS to protect the read/write head from both intentional and unanticipated touchdown events. The PMR read/write head is then mounted on a slider and the assembly is incorporated into a hard disk drive (HDD).Type: GrantFiled: March 8, 2019Date of Patent: April 21, 2020Assignees: SAE Magnetics (H.K.) Ltd., Headway Technologies, Inc.Inventors: Siu Yin Ngan, Qinghua Zeng, Ellis Cha, Kowang Liu, Xuhui Jin
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Patent number: 10566013Abstract: A light source unit for thermally-assisted magnetic head includes a substrate member having a bonding surface, multiple layers formed on the bonding surface and comprising a base layer, a connection pad layer, an insulation layer and a bonding layer; a light source assembly attached on the bonding layer of the substrate member and having a laser diode embedded therein and connected to the connection pad layer on the bonding surface, so as to form a laser diode circuit; and a heater buried in the insulation layer and connected to the connection pad layer, so as to form a heater circuit. The light source unit can maintain stable heat power for facilitating performance of the thermally-assisted magnetic head, and further reduce the sizes of the light source unit and substrate member.Type: GrantFiled: January 17, 2019Date of Patent: February 18, 2020Assignees: SAE MAGNETICS (H.K.) LTD., HEADWAY TECHNOLOGIES, INC.Inventors: Takashi Honda, Ryo Hosoi, Wah Chun Chan, Makoto Kawato, Dayu Zhou, Koji Shimazawa, Kowang Liu
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Patent number: 10482905Abstract: A dual perpendicular magnetic recording writer is disclosed wherein the better of two writers on a slider is determined by performance testing, and is then integrated into a head gimbal assembly. Main pole layers in the two writers are separated by a cross-track width <10 microns to minimize read-write offset. Each of the driving coil (DC) and bucking coil (BC) have two outer portions forming a U shape with a front side, and each have a center portion connected to the front side proximate to an air bearing surface and a backend contacting an interconnect. A write current passes from a BC outer portion below the main pole in the selected writer through the BC center portion to the interconnect, and then through the DC center portion to a DC outer portion above the main pole in the selected writer. Area density capability mean and sigma are improved.Type: GrantFiled: April 2, 2018Date of Patent: November 19, 2019Assignee: Headway Technologies, Inc.Inventors: Kowang Liu, Yuhui Tang, Moris Dovek
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Publication number: 20190304490Abstract: A dual perpendicular magnetic recording writer is disclosed wherein the better of two writers on a slider is determined by performance testing, and is then integrated into a head gimbal assembly. Main pole layers in the two writers are separated by a cross-track width<10 microns to minimize read-write offset. Each of the driving coil (DC) and bucking coil (BC) have two outer portions forming a U shape with a front side, and each have a center portion connected to the front side proximate to an air bearing surface and a backend contacting an interconnect. A write current passes from a BC outer portion below the main pole in the selected writer through the BC center portion to the interconnect, and then through the DC center portion to a DC outer portion above the main pole in the selected writer. Area density capability mean and sigma are improved.Type: ApplicationFiled: April 2, 2018Publication date: October 3, 2019Inventors: Kowang Liu, Yuhui Tang, Moris Dovek
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Patent number: 10360935Abstract: A dual perpendicular magnetic recording writer is disclosed wherein first and second dynamic fly height (DFH) heaters WDFH1 and WDFH2, are formed in first and second writers, respectively, on a slider in a head gimbal assembly. In one embodiment, WDFH1 and WDFH2 have front sides that are recessed behind first and second back gap connections (BGC), respectively, and join together at their respective backsides behind the interconnect which connects a bucking coil and driving coil each symmetrically disposed about a center plane separating the two writers. In another embodiment with a separate bucking coil in each writer, WDFH1 and WDFH2 are formed behind separate interconnects. Magnetic spacing loss is reduced compared with a single DFH heater spread across both writers. Close point at touchdown in a cross-track direction and the size of the touchdown area are controlled by applying a WDFH1:WDFH2 power ratio from 100:0 to 0:100.Type: GrantFiled: May 22, 2018Date of Patent: July 23, 2019Assignee: Headway Technologies, Inc.Inventors: Kowang Liu, Siu Yin Ngan, Qing Hua Zeng, Ellis Cha
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Patent number: 10311900Abstract: A dual PMR writer is disclosed wherein the better of the two writers on a slider is integrated into a head gimbal assembly to improve area density capability mean and sigma values, and the other writer is disabled. Each of a driving coil (DC) and bucking coil (BC) have two outer portions that form a U shape with a front side, and have a center portion connected to each of the two outer portions with a narrow arm in which direct current resistance (DCR) is enhanced during a write process. As a result, when writer (coil) induced write gap (WG) protrusion is overlaid on the dynamic fly height (DFH) protrusion profile, the net WG protrusion profile has a maximum value at a cross-track position aligned with a main pole tip in the better writer thereby substantially minimizing magnetic spacing loss compared with conventional dual PMR writers.Type: GrantFiled: January 19, 2018Date of Patent: June 4, 2019Assignee: Headway Technologies, Inc.Inventors: Kowang Liu, Yuhui Tang, Moris Dovek
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Patent number: 10279451Abstract: A dual PMR writer is disclosed wherein the better writer at outer diameter (OD) skew is paired with a suspension after dynamic performance (DP) spin stand testing so that the better writer is the inner writer formed closer to a recording disk center than the other writer. Accordingly, lower read write offset is achieved at OD skew and better area density capability is realized. Preferably, there is a symmetrical or substantially symmetrical air bearing surface design after lapping and spin stand testing to afford flexibility in pairing an up facing (UP) head configuration with an UP suspension, or a down facing (DN) head configuration with a DN suspension to enable the better writer to be the inner writer. The dual PMR writer may have a dual dynamic fly height heater on each side of a center plane separating the two writers to improve write gap protrusion in the better writer.Type: GrantFiled: April 2, 2018Date of Patent: May 7, 2019Assignee: Headway Technologies, Inc.Inventors: Yue Liu, Yuhui Tang, Moris M. Dovek, Kowang Liu
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Patent number: 9659584Abstract: Dynamic fly height (DFH) control is obtained for a read/write head by use of a heating element having two laterally separated heat sources symmetrically spaced around the track center line of the head. The two heating sources create a protrusion profile relative to the undistorted ABS that recesses the read element and main write pole at the track center line relative to off-track positions. The resulting DFH control also protects the head from HDI (head-disk interference) events that are either the result of calibration procedures or normal HDD (hard disk drive) operation.Type: GrantFiled: March 13, 2007Date of Patent: May 23, 2017Assignee: Headway Technologies, Inc.Inventor: Kowang Liu
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Patent number: 9218830Abstract: A main pole structure is selectively annealed by attaching a lead to a back side thereof and electrically connecting a lead to a front end of a narrow pole tip portion such that when a first current passes between the leads there is resistive heating that raises the temperature in the narrow pole tip to 250° C. to 400° C. As a result, defects and stress level are reduced in the narrow pole tip portion without substantially increasing a temperature in adjacent regions including the read head. Annealing may be performed with a partially completed main pole structure or with a completely fabricated write head. Leads may be removed or left in place after annealing is finished. The extent of annealing may be determined by calculating a difference between resistance measurements taken before and after annealing.Type: GrantFiled: February 26, 2014Date of Patent: December 22, 2015Assignee: Headway Technologies, Inc.Inventors: Yan Wu, Kowang Liu