Patents by Inventor Hoo-san Lee

Hoo-san Lee 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: 10026429
    Abstract: A perpendicular type of magnetic recording medium has a multi-layered recording structure made up of a plurality of ferro-magnetic layers and a non-magnetic layer interposed between the plurality of ferro-magnetic layers, and the perpendicular magnetic anisotropy energy of the lower ferro-magnetic layer is greater than the perpendicular magnetic anisotropy energy of the upper ferro-magnetic layer. Accordingly, the lower ferro-magnetic layer may be easily magnetically reversed by a magnetic field applied during a write operation. Thus, the perpendicular type of magnetic recording medium exhibits an enhanced thermal stability and write-ability.
    Type: Grant
    Filed: March 12, 2010
    Date of Patent: July 17, 2018
    Assignee: Seagate Technology LLC
    Inventors: Sok-hyun Kong, Hoo-san Lee, Sadayuki Watanabe, Shunji Takenoiri
  • Patent number: 8889274
    Abstract: An apparatus having a recording layer of a magnetic material with a concentration of implanted ions that increases in relation to a thickness direction of the recording layer to provide the recording layer with a continuously varied perpendicular magnetic anisotropy constant.
    Type: Grant
    Filed: January 28, 2013
    Date of Patent: November 18, 2014
    Assignee: Seagate Technology International
    Inventors: Seong-yong Yoon, Chee-kheng Lim, Hoo-san Lee, Hoon-sang Oh, Sok-hyun Kong
  • Patent number: 8441754
    Abstract: A servo master having a pattern capable of being magnetically transferred as a servo pattern to a magnetic recording medium, wherein the servo master is formed of a material having a magnetic anisotropic constant perpendicular to a surface of the magnetic recording medium. The magnetic transfer method can include preparing a servo master patterned with a servo pattern to be formed on a magnetic recording medium, and arranging the servo master on the magnetic recording medium and applying an external magnetic field to the servo master in a first direction perpendicular to a recording surface of the magnetic recording medium, and in a second direction parallel to the recording surface of the magnetic recording medium.
    Type: Grant
    Filed: June 16, 2009
    Date of Patent: May 14, 2013
    Assignee: Seagate Technology LLC
    Inventors: Hoo-san Lee, Sok-hyun Kong, Sung-chul Lee
  • Patent number: 8415035
    Abstract: A perpendicular magnetic recording medium is provided. The perpendicular magnetic recording medium includes: a perpendicular magnetic recording layer formed on a substrate; and at least one soft magnetic under-layer formed between the substrate and the perpendicular magnetic recording layer, wherein the soft magnetic under-layer is made from an alloy of a non-magnetic material and a magnetic material which exists in the form of granular nanoparticles in matrix of the non-magnetic material, and at least two of the magnetic nanoparticles are spaced apart from one another by a predetermined distance so as to mutually make an anti-ferromagnetic coupling.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: April 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Hoo San Lee, Hoon Sang Oh, Sok Hyun Kong, Seong Yong Yoon
  • Patent number: 8361641
    Abstract: A perpendicular magnetic recording medium and a method of manufacturing the same are provided. The perpendicular magnetic recording medium comprises a recording layer including a plurality of regions formed in the depth direction of the recording layer and a magnetic anisotropy constant of a region relatively deeper than another region, among the plurality of regions, is greater than that of the another region. The method of manufacturing a perpendicular magnetic recording medium includes: forming a recording layer having perpendicular magnetic anisotropy; and irradiating the recording layer with ions.
    Type: Grant
    Filed: January 23, 2008
    Date of Patent: January 29, 2013
    Assignee: Seagate Technology LLC
    Inventors: Seong-yong Yoon, Chee-kheng Lim, Hoo-san Lee, Hoon-sang Oh, Sok-hyun Kong
  • Patent number: 8279555
    Abstract: A magnetic recording medium and a method of manufacturing the magnetic recording medium are provided. In order to increase the recording density of the magnetic recording medium, the magnetic recording medium is configured to multiple magnetic layers by consecutively forming a first magnetic layer having a thin film shape and a second magnetic layer comprising patterned magnetic bits. The first magnetic layer has a magnetic anisotropic coefficient greater than that of the second magnetic layer.
    Type: Grant
    Filed: March 28, 2008
    Date of Patent: October 2, 2012
    Assignee: Seagate Technology International
    Inventors: Myung-bok Lee, Jin-seung Sohn, Hoo-san Lee
  • Patent number: 8164852
    Abstract: A magnetic head and a recording apparatus employing the same are provided. The magnetic head includes a recording member, a field inducing member inducing a magnetic field to the recording member, a shield member having the same direction of magnetization as the recording member in a recording operation, and a return path member forming a magnetic path with the recording member.
    Type: Grant
    Filed: June 20, 2008
    Date of Patent: April 24, 2012
    Assignee: Seagate Technology International
    Inventors: Hoo-san Lee, Hoon-sang Oh, Sung-chul Lee
  • Patent number: 8111486
    Abstract: A head gimbals assembly for a hard disk for use in a thermally assisted magnetic disk recording medium, in which a laser diode is applied so as to record information with high density. The head gimbals assembly for a hard disk having a plurality of suspensions, each of which is provided with a magnetic head positioned adjacent to a corresponding disk surface among the disks so as to record/reproduce information; a head gimbals body having a centrally formed pivot hole which allows the head gimbals body to be fitted in such a manner as to be rotatable in relation to the disks, the suspensions extending from one end of the head gimbals body; a coil rotator provided at the other end of the head gimbals body so as to rotate the head gimbals body about the pivot hole; and a laser assembly having one or more laser diodes and one or more wave guides, the light emitted from any of the laser diodes is guided to a corresponding magnetic head by the wave guides.
    Type: Grant
    Filed: February 1, 2007
    Date of Patent: February 7, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sung Dong Suh, Hyun Jei Kim, Hoo San Lee
  • Patent number: 8098456
    Abstract: A perpendicular magnetic recording head including: a data recording module comprising a main pole, a return pole, and a coil wrapped around the main pole; and a data reproduction module including magnetic shield layers and a reading device located between the magnetic shield layers, wherein the width of a lower end of the main pole is gradually reduced in a downward direction thereof, and the lower end of the main pole comprises a first part and a second part extending from the first part, the first part having a curved surface of a first curvature and the second part having a curved surface of a second curvature. The first curvature can be equal to or different from the second curvature, and magnetic shield devices can be further disposed on both sides of the lower end of the main pole.
    Type: Grant
    Filed: April 28, 2006
    Date of Patent: January 17, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chee-kheng Lim, Yong-su Kim, Hoo-san Lee
  • Patent number: 8043733
    Abstract: A bit patterned medium in which an exchange coupling layer induces exchange coupling between adjacent bits in order to reduce a switching field difference resulting from different magnetization directions of bits. The exchange coupling layer is disposed either over or under a recording layer having a plurality of bits. The exchange coupling layer induces exchange coupling between a bit which is to be recorded and an adjacent bit and reduces a switching field difference resulting from a difference between the magnetization direction of the bit to be recorded and the magnetization direction of neighboring bits due to an exchange coupling force generated during the exchange coupling.
    Type: Grant
    Filed: February 28, 2008
    Date of Patent: October 25, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Sung-chul Lee, Hoon-sang Oh
  • Patent number: 8042259
    Abstract: A magnetic recording head and a method of manufacturing the same. The magnetic recording head includes a stack containing a main pole and a return pole. The stack includes a first magnetic layer having a groove formed therein; an insulating layer covering a surface of the groove; and a second magnetic layer pattern filling the groove covered with the insulating layer.
    Type: Grant
    Filed: February 18, 2010
    Date of Patent: October 25, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Young-hun Im, Yong-su Kim
  • Patent number: 8021770
    Abstract: A perpendicular type of magnetic recording medium includes a substrate, a soft magnetic underlying section including a plurality of distinct layers soft magnetic material, a recording section, and an intermediate section upon which the recording section is formed. The intermediate section is provided to improve the crystal orientation and impart a desired magnetic characteristic to the recording section. An uppermost one of the layers of soft magnetic material which, of all of the layers of soft magnetic material, is disposed closest to the intermediate section is predisposed to induce the intermediate section to crystallize in a desired way as it is formed. Therefore, the intermediate section may have a minimal thickness and yet achieve a crystallization that is sufficient to control the forming of the recording section.
    Type: Grant
    Filed: March 12, 2010
    Date of Patent: September 20, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sok-hyun Kong, Hoo-san Lee, Sadayuki Watanabe, Shunji Takenoiri
  • Patent number: 8007931
    Abstract: A perpendicular magnetic recording medium including: a substrate; a perpendicular magnetic recording layer disposed over the substrate; a soft magnetic underlayer disposed between the substrate and the perpendicular magnetic recording layer; a shunting layer disposed under the soft magnetic underlayer; and an isolation layer disposed between the soft magnetic underlayer and the shunting layer and providing magnetic isolation between the shunting layer and the other layers disposed over the shunting layer are provided. The shunting layer is magnetically separated from the other magnetic layers disposed over the shunting layer, and shunts a magnetic field generated by the magnetic domain walls of the soft magnetic underlayer such that the magnetic field cannot reach a magnetic head, thereby increasing a signal-to-noise ratio (SNR).
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: August 30, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Chee-kheng Lim, Hoon-sang Oh, Sok-hyun Kong
  • Patent number: 7948700
    Abstract: Provided is a bit patterned medium including bridges which induce exchange coupling between adjacent bits in order to reduce a switching field difference resulting from different magnetization directions of bits. The bridges and the bits are integrally formed with each other. The bits are locally connected by the bridges. A magnetostatic force for each bit is reduced due to an exchange coupling between adjacent bits, thereby reducing a switching field distribution of the bits.
    Type: Grant
    Filed: May 27, 2008
    Date of Patent: May 24, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Sung-chul Lee, Hoon-sang Oh
  • Patent number: 7903372
    Abstract: A magnetic recording head and a method of manufacturing the same. The magnetic recording head includes a stack containing a main pole and a return pole. The stack includes a first magnetic layer having a groove formed therein; an insulating layer covering a surface of the groove; and a second magnetic layer pattern filling the groove covered with the insulating layer.
    Type: Grant
    Filed: January 11, 2006
    Date of Patent: March 8, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Young-hun Im, Yong-su Kim
  • Patent number: 7885026
    Abstract: A magnetic recording medium and a method of fabricating the same are provided. The magnetic recording medium in which a position for magnetic recording is patterned with a magnetic material, includes a magnetic recording layer which includes a data area having a plurality of data tracks, and a servo area having a servo burst for following the data tracks, wherein the servo burst includes a plurality of bursts disposed in a zigzag structure along a downtrack direction, and each of the bursts includes a plurality of burst pieces having different coercivities from each other. The magnetic recording medium is subjected to two servo-recording processes, so that a signal similar to an alternative signal written in a burst having a burst pattern used in a related art continuous medium can be obtained.
    Type: Grant
    Filed: January 23, 2008
    Date of Patent: February 8, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Hoon-sang Oh, Sung-hoon Choa
  • Patent number: 7881002
    Abstract: Provided is a method of increasing recording density and a control apparatus for increasing the recording density. The method includes applying a recording current corresponding to a recording signal to a magnetic head of a hard disc drive (HDD), and limiting a current value being applied to the magnetic head to a critical value when the recording current reaches the critical value. In the method, a rising time is reduced by using an overshoot recording current and the recording current is limited to a critical value when an actual recording current reaches the critical value. Thus, write track widths (WTWs) can be reduced at a low recording frequency, thereby increasing tracks per inch (TPI).
    Type: Grant
    Filed: November 28, 2007
    Date of Patent: February 1, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Hyun-jei Kim, Sung-hoon Choa, Hoon-sang Oh
  • Patent number: 7869264
    Abstract: An information storage device includes a record head and a data recording medium. The record head includes a magnetic substance having magnetic domain walls and records data in the data recording medium. In a method of operating the information storage device, a first high frequency current or a high frequency magnetic field is supplied to the magnetic substance while magnetic domain walls of the magnetic substance are moved.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: January 11, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoo-san Lee, Chee-kheng Lim, Hoon-sang Oh
  • Patent number: 7799445
    Abstract: A perpendicular magnetic recording medium including a soft magnetic underlayer. The perpendicular magnetic recording medium includes: a lower structural body including an anti-ferromagnetic layer; a first soft magnetic underlayer, a non-magnetic layer, and a second soft magnetic underlayer sequentially formed on the anti-ferromagnetic layer, where the thickness ratio of the second soft magnetic underlayer to that of the first soft magnetic underlayer is designed to be within specific range; and a recording layer formed on the second soft magnetic underlayer. Therefore, noise generated on the soft magnetic underlayer due to external magnetic fields of a magnetic head and a voice coil motor can be reduced greatly.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: September 21, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hoon-sang Oh, Yong-su Kim, No-yeol Park, Hoo-san Lee, Chul-min Choi
  • Publication number: 20100233515
    Abstract: A perpendicular type of magnetic recording medium has a multi-layered recording structure made up of a plurality of ferro-magnetic layers and a non-magnetic layer interposed between the plurality of ferro-magnetic layers, and the perpendicular magnetic anisotropy energy of the lower ferro-magnetic layer is greater than the perpendicular magnetic anisotropy energy of the upper ferro-magnetic layer. Accordingly, the lower ferro-magnetic layer may be easily magnetically reversed by a magnetic field applied during a write operation. Thus, the perpendicular type of magnetic recording medium exhibits an enhanced thermal stability and write-ability.
    Type: Application
    Filed: March 12, 2010
    Publication date: September 16, 2010
    Applicants: SAMSUNG ELECTRONICS CO., LTD., FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.
    Inventors: Sok-hyun Kong, Hoo-san Lee, Sadayuki Watanabe, Shunji Takenoiri