Patents by Inventor Po-Kang Wang

Po-Kang Wang 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).

  • Publication number: 20150108825
    Abstract: A fitting structure of wheel covers is revealed. A plurality of holes is disposed circularly around a wheel cover. An inner edge of each hole is projected to form a positioning seat. A fixing seat is located in the hole and is connected to a bottom edge of the positioning seat by a connecting segment. The positioning seat includes two mounting rods at two sides respectively, a hook arranged at a center, and mounting space formed between the mounting rod and the hook. The fixing seat includes mounting blocks corresponding to the mounting space and mounted with the mounting rods, and stopping bars against the mounting rods correspondingly. By the above components integrated into one piece, leaning against and mounted with each other, the assembly of the wheel cover is easy, the positioning is stable and the structural strength and stability of the wheel cover are improved.
    Type: Application
    Filed: October 18, 2013
    Publication date: April 23, 2015
    Inventor: PO-KANG WANG
  • Patent number: 8981503
    Abstract: An STT MTJ cell is formed with a magnetic anisotropy of its free and reference layers that is perpendicular to their planes of formation. The reference layer of the cell is an SAF multilayered structure with a single magnetic domain to enhance the bi-stability of the magnetoresistive states of the cell. The free layer of the cell is etched back laterally from the reference layer, so that the fringing stray field of the reference layer is no more than 15% of the coercivity of the free layer and has minimal effect on the free layer.
    Type: Grant
    Filed: March 16, 2012
    Date of Patent: March 17, 2015
    Assignee: Headway Technologies, Inc.
    Inventors: Robert Beach, Guenole Jan, Yu-Jen Wang, Witold Kula, Po-Kang Wang
  • Patent number: 8970985
    Abstract: A structure and a process for a perpendicular write pole that provides increased magnetic flux at the ABS is disclosed. This is accomplished by increasing the amount of write flux that originates above the write gap, without changing the pole taper at the ABS. Three embodiment of the invention are discussed.
    Type: Grant
    Filed: December 23, 2013
    Date of Patent: March 3, 2015
    Assignee: Headway Technologies, Inc.
    Inventors: Lijie Guan, Po-Kang Wang, Moris Dovek, Joe Smyth, Kenichi Takano, Yoshitaka Sasaki
  • Publication number: 20140347918
    Abstract: A write method for a STT-RAM MTJ is disclosed that substantially reduces the bit error rate caused by intermediate domain states generated during write pulses. The method includes a plurality of ā€œnā€ write periods or pulses and ā€œn?1ā€ domain dissipation periods where a domain dissipation period separates successive write periods. During each pulse, a write current is applied in a first direction across the MTJ and during each domain dissipation period, a second current with a magnitude equal to or less than the read current is applied in an opposite direction across the MTJ. Alternatively, no current is applied during one or more domain dissipation periods. Each domain dissipation period has a duration of 1 to 10 ns that is equal to or greater than the precession period of free layer magnetization in the absence of spin torque transfer current.
    Type: Application
    Filed: May 22, 2013
    Publication date: November 27, 2014
    Applicant: Headway Technologies, Inc.
    Inventors: Yuan-Jen Lee, Po-Kang Wang, Guenole Jan
  • Patent number: 8817420
    Abstract: As track densities increase, it becomes increasingly important, while writing in a given track, not to inadvertently write data in adjoining tracks. This problem has been overcome by limiting the width of material in the ABS plane to what it is at the write gap. The part of the lower pole that is wider than this is recessed back away from the ABS, thereby greatly reducing its magnetic influence on adjacent tracks. Four different embodiments of write heads that incorporate this notion are described together with a description of a general process for their manufacture.
    Type: Grant
    Filed: February 6, 2012
    Date of Patent: August 26, 2014
    Assignee: Headway Technologies, Inc.
    Inventors: Moris Dovek, Glen Garfunkel, Po Kang Wang
  • Publication number: 20140211550
    Abstract: Embodiments are directed to detecting a state of a memory element in a memory device, comprising: applying a pulse of a predetermined magnitude and duration to the memory element to induce a transition in the state of the memory element when a polarity of the pulse is opposite to the state, monitoring, by a device, a signal associated with the memory element to detect a presence or absence of a transition in the signal in an amount greater than a threshold, and determining the state of the memory element based on said monitoring.
    Type: Application
    Filed: January 31, 2013
    Publication date: July 31, 2014
    Applicants: HEADWAY TECHNOLOGIES, INC., INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Jonathan Z. Sun, John K. DeBrosse, Po-Kang Wang
  • Patent number: 8767349
    Abstract: As track densities increase, it becomes increasingly important, while writing in a given track, not to inadvertently write data in adjoining tracks. This problem has been overcome by limiting the width of material in the ABS plane to what it is at the write gap. The part of the lower pole that is wider than this is recessed back away from the ABS, thereby greatly reducing its magnetic influence on adjacent tracks. Four different embodiments of write heads that incorporate this notion are described together with a description of a general process for their manufacture.
    Type: Grant
    Filed: February 6, 2012
    Date of Patent: July 1, 2014
    Assignee: Headway Technologies, Inc.
    Inventors: Moris Dovek, Glen Garfunkel, Po Kang Wang
  • Patent number: 8728825
    Abstract: A GMR sensor stripe provides a sensitive mechanism for detecting the presence of magnetized particles bonded to biological molecules that are affixed to a substrate. The adverse effect of hysteresis on the maintenance of a stable bias point for the magnetic moment of the sensor stripe free layer is eliminated by a combination of biasing the sensor stripe along its longitudinal direction rather than the usual transverse direction and by using the overcoat stress and magnetostriction of magnetic layers to create a compensatory transverse magnetic anisotropy. By connecting the stripes in an array and making the spaces between the stripes narrower than the dimension of the magnetized particle and by making the width of the stripes equal to the dimension of the particle, the sensitivity of the sensor array is enhanced.
    Type: Grant
    Filed: March 12, 2012
    Date of Patent: May 20, 2014
    Assignee: Headway Technologies, Inc.
    Inventors: Po-Kang Wang, Xizeng Shi, Chyu-Jiuh Torng
  • Publication number: 20140111886
    Abstract: A structure and a process for a perpendicular write pole that provides increased magnetic flux at the ABS is disclosed. This is accomplished by increasing the amount of write flux that originates above the write gap, without changing the pole taper at the ABS. Three embodiment of the invention are discussed.
    Type: Application
    Filed: December 23, 2013
    Publication date: April 24, 2014
    Applicant: Headway Technologies, Inc.
    Inventors: Lijie Guan, Po-Kang Wang, Moris Dovek, Joe Smyth, Kenichi Takano, Yoshitaka Sasaki
  • Publication number: 20140111887
    Abstract: A structure and a process for a perpendicular write pole that provides increased magnetic flux at the ABS is disclosed. This is accomplished by increasing the amount of write flux that originates above the write gap, without changing the pole taper at the ABS. Three embodiment of the invention are discussed.
    Type: Application
    Filed: December 23, 2013
    Publication date: April 24, 2014
    Applicant: Headway Technologies, Inc.
    Inventors: Lijie Guan, Po-Kang Wang, Moris Dovek, Joe Smyth, Kenichi Takano, Yoshitaka Sasaki
  • Patent number: 8693273
    Abstract: A sense amplifier comprising a reference current developed from a programmed and a non-programmed reference cell is used to read a signal from a magnetic random access memory (MRAM) comprising magnetic tunnel junction (MTJ) cells. The average current is determined from reference cells in as few as one sense amplifier and as many as n sense amplifiers, and is an average current between the programmed reference cell and the non-programmed reference cell that approximates the mid point between the two states. The sense amplifier can be fully differential or a non differential sense amplifier.
    Type: Grant
    Filed: January 6, 2012
    Date of Patent: April 8, 2014
    Assignee: Headway Technologies, Inc.
    Inventors: Perng-Fei Yuh, Po-Kang Wang, Lejan Pu
  • Patent number: 8625234
    Abstract: A structure and a process for a perpendicular write pole that provides increased magnetic flux at the ABS is disclosed. This is accomplished by increasing the amount of write flux that originates above the write gap, without changing the pole taper at the ABS. Three embodiment of the invention are discussed.
    Type: Grant
    Filed: April 29, 2008
    Date of Patent: January 7, 2014
    Assignee: Headway Technologies, Inc.
    Inventors: Lijie Guan, Po-Kang Wang, Moris Dovek, Joe Smyth, Kenichi Takano, Yoshitaka Sasaki
  • Patent number: 8593915
    Abstract: A slider mounted TAMR (Thermal Assisted Magnetic Recording), DFH (Dynamic Flying Height) type read/write head using optical-laser generated surface plasmons in a small antenna to locally heat a magnetic medium, uses the same optical laser at low power to pre-heat the antenna. Maintaining the antenna at this pre-heated temperature, approximately 50% of its highest temperature during write operations, allows the DFH mechanism sufficient time to compensate for the thermal protrusion of the antenna at that lower temperature, so that thermal protrusion transients are significantly reduced when a writing operation occurs and full laser power is applied. The time constant for antenna protrusion is less than the time constant for DFH fly height compensation, so, without pre-heating, the thermal protrusion of the antenna due to absorption of optical radiation cannot be compensated by the DFH effect.
    Type: Grant
    Filed: August 1, 2011
    Date of Patent: November 26, 2013
    Assignee: Headway Technologies, Inc.
    Inventors: Erhard Schreck, Kowang Liu, Kouji Shimazawa, Po-Kang Wang
  • Patent number: 8567045
    Abstract: As track densities increase, it becomes increasingly important, while writing in a given track, not to inadvertently write data in adjoining tracks. This problem has been overcome by limiting the width of material in the ABS plane to what it is at the write gap. The part of the lower pole that is wider than this is recessed back away from the ABS, thereby greatly reducing its magnetic influence on adjacent tracks. Four different embodiments of write heads that incorporate this notion are described together with a description of a general process for their manufacture.
    Type: Grant
    Filed: February 6, 2012
    Date of Patent: October 29, 2013
    Assignee: Headway Technologies, Inc.
    Inventors: Moris Dovek, Glen Garfunkel, Po Kang Wang
  • Patent number: 8542464
    Abstract: As track densities increase, it becomes increasingly important, while writing in a given track, not to inadvertently write data in adjoining tracks. This problem has been overcome by limiting the width of material in the ABS plane to what it is at the write gap. The part of the lower pole that is wider than this is recessed back away from the ABS, thereby greatly reducing its magnetic influence on adjacent tracks. Four different embodiments of write heads that incorporate this notion are described together with a description of a general process for their manufacture.
    Type: Grant
    Filed: February 6, 2012
    Date of Patent: September 24, 2013
    Assignee: Headway Technologies, Inc.
    Inventors: Moris Dovek, Glen Garfunkel, Po Kang Wang
  • Publication number: 20130240963
    Abstract: An STT MTJ cell is formed with a magnetic anisotropy of its free and reference layers that is perpendicular to their planes of formation. The reference layer of the cell is an SAF multilayered structure with a single magnetic domain to enhance the bi-stability of the magnetoresistive states of the cell. The free layer of the cell is etched back laterally from the reference layer, so that the fringing stray field of the reference layer is no more than 15% of the coercivity of the free layer and has minimal effect on the free layer.
    Type: Application
    Filed: March 16, 2012
    Publication date: September 19, 2013
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Robert Beach, Guenole Jan, Yu-Jen Wang, Witold Kula, Po-Kang Wang
  • Patent number: 8525280
    Abstract: An MRAM array of MTJ memory cells is provided wherein each such cell is a layered MTJ structure located at an intersection of a word and bit line and has a small circular horizontal cross-section of 1.0 microns or less in diameter and wherein the ferromagnetic free layer of each such cell has a magnetic anisotropy produced by a magnetic coupling with a thin antiferromagnetic layer that is formed on the free layer. The array of MTJ memory cells so provided is far less sensitive to shape irregularities and edge defects of individual cells than arrays of the prior art.
    Type: Grant
    Filed: July 26, 2011
    Date of Patent: September 3, 2013
    Assignee: Headway Technologies, Inc.
    Inventors: Tai Min, Cheng Horng, Po Kang Wang
  • Patent number: 8497559
    Abstract: A CPP MTJ MRAM unit cell utilizes transfer of spin angular momentum as a mechanism for changing the magnetic moment direction of a free layer. The strength of the switching field, Hs of the cell is controlled by the magnetic anisotropy of the cell which, in turn, is controlled by a combination of the shape anisotropy and the stress and magnetostriction of the cell free layer. The coefficient of magnetostriction of the free layer can be adjusted by methods such as adding Nb or Hf to alloys of Ni, Fe, Co and B or by forming the free layer as a lamination of layers having different values of their coefficients of magnetostriction. Thus, by tuning the coefficient of magnetostriction of the cell free layer it is possible to produce a switching field of sufficient magnitude to render the cell thermally stable while maintaining a desirable switching current.
    Type: Grant
    Filed: October 10, 2007
    Date of Patent: July 30, 2013
    Assignee: MagIC Technologies, Inc.
    Inventors: Tai Min, Po Kang Wang
  • Patent number: 8422287
    Abstract: An MRAM array structure and a method of its operation that is not subject to accidental writing on half-selected elements. Each element of the MRAM is an MTJ (magnetic tunneling junction) cell operating in accord with an STT (spin torque transfer) scheme for changing its free layer magnetization state and each cell is patterned to have a C-shape in the horizontal plane. The cell thereby operates by C-mode switching to provide stability against accidental writing by half-selection. During operation, switching of a cell's magnetization is accomplished with the assist of the pulsed magnetic fields of additional word lines that are formed either orthogonal to or parallel to the existing bit lines and that can carry currents in either direction as required to provide the assist.
    Type: Grant
    Filed: September 9, 2010
    Date of Patent: April 16, 2013
    Assignee: MagIC Technologies, Inc.
    Inventors: Tai Min, Qiang Chen, Po Kang Wang
  • Publication number: 20120169332
    Abstract: A sensor array comprising a series connection of parallel GMR sensor stripes provides a sensitive mechanism for detecting the presence of magnetized particles bonded to biological molecules that are affixed to a substrate. The adverse effect of hysteresis on the maintenance of a stable bias point for the magnetic moment of the sensor free layer is eliminated by a combination of biasing the sensor along its longitudinal direction rather than the usual transverse direction and by using the overcoat stress and magnetostriction of magnetic layers to create a compensatory transverse magnetic anisotropy. By making the spaces between the stripes narrower than the dimension of the magnetized particle and by making the width of the stripes equal to the dimension of the particle, the sensitivity of the sensor array is enhanced.
    Type: Application
    Filed: March 12, 2012
    Publication date: July 5, 2012
    Applicant: MAGIC TECHNOLOGIES, INC.
    Inventors: Po-Kang Wang, Xizeng Shi, Chyu-Jiuh Torng