Patents by Inventor CheukWing Leung

CheukWing Leung 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).

  • Patent number: 10486283
    Abstract: A manufacturing method of a slider includes steps of: (a) providing a row bar with a plurality of slider elements connecting together; (b) lapping surfaces of the row bar so as to obtain a predetermined requirement; (c) lowering the temperature of the surfaces lapped in the step (b) before and/or during lapping; and (d) cutting the row bar into a plurality of sliders. The present invention can prevent a local high temperature generated on the magnetic head during lapping so that the performance of the magnetic head is improved.
    Type: Grant
    Filed: July 6, 2017
    Date of Patent: November 26, 2019
    Assignee: SAE MAGNETICS (H.K.) LTD.
    Inventors: Chiuming Lueng, Mankit Lee, Lorest Garcia Pingul, Yasutoshi Fujita, Cheukman Lui, Chiyuen Mok, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Patent number: 9899046
    Abstract: A method of testing anti-high temperature performance of a magnetic head comprises applying a plurality of second magnetic fields with different intensities in a second direction to the magnetic head, and measuring a second output parameter curve, and judging whether a variation that is beyond an allowable value is presented on the second output parameter curve, therein the second direction passes through the ABS and at an angle whose absolute value is an acute angle to the ABS. The present invention can screen out defective magnetic heads that possess poor anti-high temperature performance without heating the magnetic head.
    Type: Grant
    Filed: April 29, 2011
    Date of Patent: February 20, 2018
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Cheukman Lui, Chiuming Lueng, Hokei Lam, Mankit Lee, Kwokkam Leung, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Publication number: 20170304987
    Abstract: A manufacturing method of a slider includes steps of: (a) providing a row bar with a plurality of slider elements connecting together; (b) lapping surfaces of the row bar so as to obtain a predetermined requirement; (c) lowering the temperature of the surfaces lapped in the step (b) before and/or during lapping; and (d) cutting the row bar into a plurality of sliders. The present invention can prevent a local high temperature generated on the magnetic head during lapping so that the performance of the magnetic head is improved.
    Type: Application
    Filed: July 6, 2017
    Publication date: October 26, 2017
    Inventors: Chiuming LUENG, MANKIT LEE, LOREST GARCIA PINGUL, YASUTOSHI FUJITA, CHEUKMAN LUI, CHIYUEN MOK, CHEUKWING LEUNG, JUREN DING, RONGKWANG NI
  • Patent number: 9355660
    Abstract: A testing method of a magnetic head includes: applying a first magnetic field with a constant intensity in a first direction that is the same with that of the longitudinal bias field to the magnetic head, simultaneously applying a second magnetic field with variant intensities in a second direction traversing the air bearing surface, and measuring a first noise; applying a third magnetic field with a constant intensity in a third direction that is opposite to the first direction to the magnetic head, simultaneously applying the second magnetic field with variant intensities in the second direction, and measuring a second noise; and analyzing noise change between the first noise and the second noise. The invention can screen out defective magnetic heads that possess poor noise characteristic and unstable performance.
    Type: Grant
    Filed: June 21, 2013
    Date of Patent: May 31, 2016
    Assignee: SAE MAGNETICS (H.K.) LTD.
    Inventors: Hokei Lam, Mankit Lee, Cheukman Lui, Wahchun Chan, Juren Ding, Rongkwang Ni, Cheukwing Leung, Wanyin Kwan
  • Patent number: 9121888
    Abstract: A method of testing anti-high temperature performance of a magnetic head comprises applying a second magnetic field with different intensities in a second direction and the changing first magnetic fields in a first direction, and measuring a plurality of second output parameter curves; and judging whether a variation that is beyond an allowable value is presented on the second output parameter curves, thereby screening out a defective magnetic head, therein the first direction is perpendicular to the air bearing surface of the magnetic head, and the second direction is perpendicular to the shielding layers of the magnetic head. The present invention can screen out defective magnetic heads that possess poor anti-high temperature performance without heating the magnetic head and with high precision.
    Type: Grant
    Filed: April 29, 2011
    Date of Patent: September 1, 2015
    Assignee: SAE MAGNETICS (H.K.) LTD.
    Inventors: Chiuming Lueng, Cheukman Lui, Mankit Lee, Hokei Lam, Kwokkam Leung, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Patent number: 9019665
    Abstract: A reader sensor comprises a first shielding layer, a second shielding layer, a read element formed therebetween, and a pair of permanent magnet layer respectively placed on two sides of the read element; and it further comprises a magnetic field generating means formed beside the read element and arranged for providing a magnetic field with a direction perpendicular to the first shielding layer and the second shielding layer, thereby stabilizing the reading performance of the reader sensor. The invention can stabilize the reading performance, ameliorate the unstable defective reader sensor, and decrease the waste and the manufacturing cost. The present invention also discloses a magnetic head, a HGA and a disk drive unit.
    Type: Grant
    Filed: May 12, 2011
    Date of Patent: April 28, 2015
    Assignee: SAE Magnetic (H.K.) Ltd.
    Inventors: Chiuming Lueng, Mankit Lee, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Patent number: 8984738
    Abstract: A manufacturing method of a slider includes steps of (a) providing a row bar with a plurality of slider elements connecting together, the row bar having an air bearing surface, a back surface opposite the air bearing surface, a bonding surface and a bottom surface opposite the bonding surface; (b) grinding the bottom surface of the row bar; (c) lapping the air bearing surface of the row bar so as to obtain a predetermined requirement, and applying a first magnetic field with a first direction during lapping the air bearing surface, and the first direction being parallel to the air bearing surface and the bonding surface; and (d) cutting the row bar into a plurality of individual sliders. The present invention can maintain a good performance of a magnetic head during the manufacturing process.
    Type: Grant
    Filed: February 22, 2012
    Date of Patent: March 24, 2015
    Assignee: SAE Magnetics (H.K.) Ltd
    Inventors: Chiuming Lueng, Mankit Lee, Lorest Garcia Pingul, Yasutoshi Fujita, Cheukman Lui, ChiYuen Mok, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Publication number: 20140334279
    Abstract: A testing method of a magnetic head includes: applying a first magnetic field with a constant intensity in a first direction that is the same with that of the longitudinal bias field to the magnetic head, simultaneously applying a second magnetic field with variant intensities in a second direction traversing the air bearing surface, and measuring a first noise; applying a third magnetic field with a constant intensity in a third direction that is opposite to the first direction to the magnetic head, simultaneously applying the second magnetic field with variant intensities in the second direction, and measuring a second noise; and analyzing noise change between the first noise and the second noise. The invention can screen out defective magnetic heads that possess poor noise characteristic and unstable performance.
    Type: Application
    Filed: June 21, 2013
    Publication date: November 13, 2014
    Inventors: Hokei LAM, Mankit LEE, Cheukman LUI, Wahchun CHAN, Juren DING, Rongkwang NI, Cheukwing LEUNG, Wanyin KWAN
  • Patent number: 8767356
    Abstract: An MR sensor includes a first shielding layer, a second shielding layer, an MR element formed therebetween, and a pair of hard magnet layers respectively placed on two sides of the MR element. The MR element includes an AFM layer formed on the first shielding layer, a pinned layer formed on the AFM layer and a free layer formed between the pinned layer and the second shielding layer. The free layer is funnel-shaped, which has a first edge facing an air bearing surface and a second edge opposite the first edge, and the first edge has a narrower width than that of the second edge. The MR sensor can improve MR height control performance, and improve the ESD performance and decrease the PCN and RTN and, in turn, get a more stable performance. The present invention also discloses a magnetic head, an HGA and a disk drive unit.
    Type: Grant
    Filed: June 11, 2010
    Date of Patent: July 1, 2014
    Assignees: SAE Magnetics (H.K.) Ltd., TDK Corporation
    Inventors: Chiuming Leung, Kosuke Tanaka, Kazuki Sato, Cheukwing Leung, Juren Ding, Rongkwang Ni, Wanyin Kwan, Mankit Lee
  • Patent number: 8664950
    Abstract: A method for measuring longitudinal bias magnetic field in a tunnel magnetoresistive sensor of a magnetic head, the method includes the steps of: applying an external longitudinal time-changing magnetic field onto the tunnel magnetoresistive sensor; determining a shield saturation value of the tunnel magnetoresistive sensor under the application of the external longitudinal time-changing magnetic field; applying an external transverse time-changing magnetic field and an external longitudinal DC magnetic field onto the tunnel magnetoresistive sensor; determining a plurality of different output amplitudes under the application of the external transverse time-changing magnetic field and the application of different field strength values of the external longitudinal DC magnetic field; plotting a graph according to the different output amplitudes and the different field strength values; and determining the strength of the longitudinal bias magnetic field according to the graph and the shield saturation value.
    Type: Grant
    Filed: July 1, 2011
    Date of Patent: March 4, 2014
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Siuman Mok, Hokei Lam, Cheukwing Leung, Juren Ding, Rongkwang Ni, Wanyin Kwan, Cheukman Lui, Chiuming Lueng
  • Patent number: 8634157
    Abstract: A close loop method for measuring head SNR, for a storage device comprising a storage media and a head, comprising steps of: (a) loading the head on the media with a dynamic fly height; (b) measuring an initial environmental temperature value T1 and measuring the head signal signalload; (c) unloading the head; (d) adjusting a power which controls the dynamic fly height until a real-time environmental temperature value T2 is equal to the initial environmental temperature T1; (e) measuring the head noise value noiseunload, (f) calculating the head SNR with the follow equation: Head_SNR = 20 × log ? ( signal load noise unload ) . The method of the present invention can obtain a fair condition between the signal and noise measurement, thereby a reliable and accurate head SNR can be obtain. The present invention also provides a close loop method for measuring media SNR.
    Type: Grant
    Filed: May 12, 2011
    Date of Patent: January 21, 2014
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Chiuming Lueng, Mankit Lee, Wanyin Kwan, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Patent number: 8594967
    Abstract: A method for measuring a temperature rise induced by bias current/bias voltage in a magnetic tunnel junction includes: (a) applying an external time-changing magnetic field to the magnetic tunnel junction; (b) measuring different first outer pin flip field values under different temperature values; (c) correlating the temperature values with the outer pin flip field values; (d) measuring different second outer pin flip field values under different bias current/bias voltage values; (e) correlating the different bias current/bias voltage-values with the measured different second outer pin flip field values; and (f) correlating temperature values and bias current/bias voltage values according to the results produced by (c) and (e). The method can determine what kind of TMR reader design provides more stable and reliable reading performance, especially under higher operational temperatures.
    Type: Grant
    Filed: March 9, 2011
    Date of Patent: November 26, 2013
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Mankit Lee, Chiuming Lueng, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Patent number: 8582248
    Abstract: A MR sensor comprises a first shielding layer, a second shielding layer, a MR element and a pair of hard magnet layers sandwiched therebetween, and a non-magnetic insulating layer formed at a side of the MR element far from an air bearing surface of a slider. The MR sensor further comprises a first non-magnetic conducting layer formed between the first shielding layer and the MR element, and the first non-magnetic conducting layer is embedded in the first shielding layer and kept separate from the ABS. The MR sensor of the invention can obtain a narrower read gap to increase the resolution power and improve the reading performance, and obtain a strong longitudinal bias field to stabilize the MR sensor so as to increase the total sensor area and, in turn, get an improved reliability and performance. The present invention also discloses a magnetic head, a HGA and a disk drive unit.
    Type: Grant
    Filed: January 6, 2011
    Date of Patent: November 12, 2013
    Assignees: SAE Magnetics (H.K.) Ltd., TDK Corporation
    Inventors: Chiuming Lueng, Kazuki Sato, Yohei Koyanagi, Cheukwing Leung, Juren Ding, Rongkwang Ni, Wanyin Kwan, Siuman Mok
  • Publication number: 20130219699
    Abstract: A manufacturing method of a slider includes steps of: (a) providing a row bar with a plurality of slider elements connecting together; (b) lapping surfaces of the row bar so as to obtain a predetermined requirement; (c) lowering the temperature of the surfaces lapped in the step (b) before and/or during lapping; and (d) cutting the row bar into a plurality of sliders. The present invention can prevent a local high temperature generated on the magnetic head during lapping so that the performance of the magnetic head is improved.
    Type: Application
    Filed: February 29, 2012
    Publication date: August 29, 2013
    Applicant: SAE Magnetics (H.K.) Ltd.
    Inventors: Chiuming Lueng, Mankit Lee, Lorest Garcia Pingul, Yasutoshi Fujita, Cheukman Lui, ChiYuen Mok, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Publication number: 20130212871
    Abstract: A manufacturing method of a slider includes steps of (a) providing a row bar with a plurality of slider elements connecting together, the row bar having an air bearing surface, a back surface opposite the air bearing surface, a bonding surface and a bottom surface opposite the bonding surface; (b) grinding the bottom surface of the row bar; (c) lapping the air bearing surface of the row bar so as to obtain a predetermined requirement, and applying a first magnetic field with a first direction during lapping the air bearing surface, and the first direction being parallel to the air bearing surface and the bonding surface; and (d) cutting the row bar into a plurality of individual sliders. The present invention can maintain a good performance of a magnetic head during the manufacturing process.
    Type: Application
    Filed: February 22, 2012
    Publication date: August 22, 2013
    Applicant: SAE Magnetics (H.K.) Ltd.
    Inventors: Chiuming Lueng, Mankit Lee, Lorest Garcia Pingul, Yasutoshi Fujita, Cheukman Lui, ChiYuen Mok, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Patent number: 8493683
    Abstract: Measuring method of a magnetic head includes (a) placing the magnetic head at normal position, defining a first direction parallel to an air bearing surface and two shielding layers of the magnetic head, and defining a second direction perpendicular to the first direction; (b) tilting the magnetic head at an angle to the second direction, applying a plurality of first magnetic fields with different intensities in the first direction, and measuring out a first output parameter curve; (c) repeating the step (b) with different angles and measuring out a plurality of first output parameter curves; (d) calculating a plurality of pinned direction tilt ratios that a pinned direction of a pinned layer of the magnetic head tilts towards the second direction according to the parameter curves; and (e) calculating a pinned direction tilt angle that the pinned direction tilts towards the second direction according to the pinned direction tilting ratios.
    Type: Grant
    Filed: November 4, 2011
    Date of Patent: July 23, 2013
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Chiu ming Lueng, Mankit Lee, Cheukwing Leung, Ju ren Ding, Rong kwang Ni
  • Publication number: 20130114387
    Abstract: Measuring method of a magnetic head includes (a) placing the magnetic head at normal position, defining a first direction parallel to an air bearing surface and two shielding layers of the magnetic head, and defining a second direction perpendicular to the first direction; (b) tilting the magnetic head at an angle to the second direction, applying a plurality of first magnetic fields with different intensities in the first direction, and measuring out a first output parameter curve; (c) repeating the step (b) with different angles and measuring out a plurality of first output parameter curves; (d) calculating a plurality of pinned direction tilt ratios that a pinned direction of a pinned layer of the magnetic head tilts towards the second direction according to the parameter curves; and (e) calculating a pinned direction tilt angle that the pinned direction tilts towards the second direction according to the pinned direction tilting ratios.
    Type: Application
    Filed: November 4, 2011
    Publication date: May 9, 2013
    Applicant: SAE MAGNETICS (H.K.) LTD.
    Inventors: Chiu ming LUENG, Mankit LEE, Cheukwing LEUNG, Ju ren DING, Rong kwang NI
  • Publication number: 20120287534
    Abstract: A reader sensor comprises a first shielding layer, a second shielding layer, a read element formed therebetween, and a pair of permanent magnet layer respectively placed on two sides of the read element; and it further comprises a magnetic field generating means formed beside the read element and arranged for providing a magnetic field with a direction perpendicular to the first shielding layer and the second shielding layer, thereby stabilizing the reading performance of the reader sensor. The invention can stabilize the reading performance, ameliorate the unstable defective reader sensor, and decrease the waste and the manufacturing cost. The present invention also discloses a magnetic head, a HGA and a disk drive unit.
    Type: Application
    Filed: May 12, 2011
    Publication date: November 15, 2012
    Applicant: SAE Magnetics (H.K.) Ltd.
    Inventors: Chiuming Lueng, Mankit Lee, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Publication number: 20120287529
    Abstract: A close loop method for measuring head SNR, for a storage device comprising a storage media and a head, comprising steps of: (a) loading the head on the media with a dynamic fly height; (b) measuring an initial environmental temperature value Ti and measuring the head signal signalload; (c) unloading the head; (d) adjusting a power which controls the dynamic fly height until a real-time environmental temperature value T2 is equal to the initial environmental temperature T1; (e) measuring the head noise value noiseunload, (f) calculating the head SNR with the follow equation: Head_SNR = 20 × log ? ( signal load noise unload ) . The method of the present invention can obtain a fair condition between the signal and noise measurement, thereby a reliable and accurate head SNR can be obtain. The present invention also provides a close loop method for measuring media SNR.
    Type: Application
    Filed: May 12, 2011
    Publication date: November 15, 2012
    Applicant: SAE Magnetics (H.K.) Ltd.
    Inventors: Chiuming Lueng, Mankit Lee, Wanyin Kwan, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Publication number: 20120275047
    Abstract: A method of testing anti-high temperature performance of a magnetic head comprises applying a plurality of second magnetic fields with different intensities in a second direction to the magnetic head, and measuring a second output parameter curve, and judging whether a variation that is beyond an allowable value is presented on the second output parameter curve, therein the second direction passes through the ABS and at an angle whose absolute value is an acute angle to the ABS. The present invention can screen out defective magnetic heads that possess poor anti-high temperature performance without heating the magnetic head.
    Type: Application
    Filed: April 29, 2011
    Publication date: November 1, 2012
    Applicant: SAE Magnetics (H.K.) Ltd.
    Inventors: Cheukman Lui, Chiuming Lueng, Hokei Lam, Mankit Lee, Kwokkam Leung, Cheukwing Leung, Juren Ding, Rongkwang Ni