Patents by Inventor Ellis Cha

Ellis Cha 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: 8576671
    Abstract: A TAMR (thermal assisted magnetic recording) equipped DFH (dynamic flying height) type slider ABS design, when operating in a HDD (hard disk drive) produces exceptional low pressure/stiffness for improved touch down detection and back-off efficiency as well as wear and damage reduction due to the improved capabilities as well as reduction in heat transfers. The supplementation of the slider with multiple heaters, three herein, disposed about the write-head in the cross-track direction provides the slider with enhanced dynamic stability that would normally not be achievable with the exceptional low pressure/stiffness.
    Type: Grant
    Filed: December 7, 2012
    Date of Patent: November 5, 2013
    Assignees: SAE Magnetics (H.K) Ltd., Headway Technologies, Inc.
    Inventors: Ellis Cha, Ben Kwun Pan Ng
  • Publication number: 20130250446
    Abstract: A method to compensate for spacing variations between a dynamic fly height (DFH) controlled read/write head and a rotating disk surface. Using a HDI sensor or equivalent indicator of touchdowns, a power profile is calculated for an arbitrary track on a disk. The profile tracks disk topography by recording touchdown power at each of a series of sectors into which the track is subdivided. The resulting power profile, smoothed and expressed as a function of sector position, substitutes for the usual constant TD power setting that provides only an uncompensated range of spacing variations. A fixed back-off spacing power is added to the power profile enabling the head to fly over the track at a constant spacing. The power profile can be calculated to account for various temperature and pressure conditions.
    Type: Application
    Filed: March 20, 2012
    Publication date: September 26, 2013
    Applicants: HEADWAY TECHNOLOGIES, INC., SAE MAGNETICS (HK) LTD.
    Inventors: Qinghua Zeng, Ellis Cha
  • Publication number: 20130250455
    Abstract: A method for determining the surface distortions of a disk in a spin-stand or single or multiple disk hard disk drive (HDD) utilizing a DFH type write head. A stepwise power curve is supplied to the DFH head, the head is flown over a chosen track on the disk, and the high frequency signal from a HDI sensor is analyzed in order to determine the step of an initial touchdown power and the step of a complete touchdown power as a function of individual sectors in a sector subdivision along a chosen track. The HDI sensor signal is averaged within each step of the power curve between these two steps and a Ratio variable, Ratio=(Max. amplitude)/(RMS amplitude) is calculated for each step and is averaged over each rotation of the disk during the step.
    Type: Application
    Filed: March 20, 2012
    Publication date: September 26, 2013
    Applicants: HEADWAY TECHNOLOGIES, INC., SAE MAGNETICS (HK) LTD.
    Inventors: Qinghua Zeng, Ellis Cha, Soramany Ka
  • Publication number: 20130094104
    Abstract: Dynamic fly height (DFH) controlled read/write heads using multiple heaters have their heater powers set within a range of ratios that allows minimum clearances to be set between the read-gap and the write-gap and the surface of a disk, thereby providing improved touch-down detection. Determining the correct range of power ratios requires varying the ratio to create an adjustable protrusion profile for the read and write elements in the head and measuring values of the ratio and corresponding values of read gap and write gap clearances that create points of minimum clearance. By adjusting the ratio of power supplied to the heaters, different protrusion profiles can be produced, clearance control for sigma reduction can be obtained and read/write readiness and operation consistency and reliability can be improved.
    Type: Application
    Filed: October 17, 2011
    Publication date: April 18, 2013
    Inventors: Siu Yin Ngan, Qinghua Zeng, Ellis Cha
  • Patent number: 8218269
    Abstract: Gimbal designs are provided that minimize adverse dynamic performance of a HDD suspension, particularly subsequent to head-disk-interface (HDI) interactions. The improvement of operational performance can be seen in graphical representations of the vibrational modes of a gimbal mounted slider subsequent to such HDI interactions. Each gimbal design includes a ramp limiter formed as two separated arms connected by one or two transverse bars and a routing of conducting traces that relieves stress and minimally contacts these bars.
    Type: Grant
    Filed: August 15, 2011
    Date of Patent: July 10, 2012
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
  • Patent number: 8184405
    Abstract: A slider is formed by a three-step ion milling process with an ABS topography that provides aerodynamic stability at sub-nanometer flying heights. The ABS design significantly eliminates the accumulation of lubricant and removes whatever lubricant does accumulate by use of a shallow dam at the trailing edge. In addition, a junction between a down-track channel and a cross-track channel directs airflow towards a center pad in which a transducer is embedded so that the pressure at the pad is enhanced even under high altitude conditions. The slider ABS is divided into two portions by a transverse deep air channel, but the channel is bridged by the cross-track channel which crosses the deep air channel with sides of unequal height. This dual height bridge allows variations in skew angle to be compensated so that pressure variations across the disk tracks are significantly reduced.
    Type: Grant
    Filed: January 14, 2011
    Date of Patent: May 22, 2012
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Guoqiang Zheng, Ellis Cha, Zhu Feng, Sindy Yeung
  • Publication number: 20110299196
    Abstract: Gimbal designs are provided that minimize adverse dynamic performance of a HDD suspension, particularly subsequent to head-disk-interface (HDI) interactions. The improvement of operational performance can be seen in graphical representations of the vibrational modes of a gimbal mounted slider subsequent to such HDI interactions. Each gimbal design includes a ramp limiter formed as two separated arms connected by one or two transverse bars and a routing of conducting traces that relieves stress and minimally contacts these bars.
    Type: Application
    Filed: August 15, 2011
    Publication date: December 8, 2011
    Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
  • Patent number: 8054585
    Abstract: In a suspension in a hard disk drive, a gimbal with asymmetric dynamic properties, in which the two halves of the gimbal may have different stiffness distribution or inertia distribution. Structural difference between the two halves, or materials with different stiffness, may cause the different stiffness distribution or inertia distribution. When the suspension vibrates, the different stiffness and/or inertia distribution increase the friction between the gimbal and a load beam of the suspension, and increase the damping of the suspension.
    Type: Grant
    Filed: November 28, 2006
    Date of Patent: November 8, 2011
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Qinghua Zeng, Yen Fu, Ellis Cha
  • Patent number: 8000061
    Abstract: Gimbal designs are provided that minimize adverse dynamic performance of a HDD suspension, particularly subsequent to head-disk-interface (HDI) interactions. The improvement of operational performance can be seen in graphical representations of the vibrational modes of a gimbal mounted slider subsequent to such HDI interactions. Each gimbal design includes a ramp limiter formed as two separated arms connected by one or two transverse bars and a routing of conducting traces that relieves stress and minimally contacts these bars.
    Type: Grant
    Filed: March 5, 2010
    Date of Patent: August 16, 2011
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
  • Patent number: 7969685
    Abstract: A DFH (Dynamic Flying Height) type slider ABS design has a stable flying height and a DFH efficiency that is uniform across the entire disk surface. These properties are a result of embedding the read/write head and heater in a trapezoidally bridged micro-pad having a very small surface area. The micro-pad is surrounded by a wing-like structure that projects from a central rail in the ABS and the micro pad is connected to an inner edge of that structure by a bridge having a trapezoidal shape. The trapezoidal shape responds effectively to variations in air flow direction and pressure point as the slider moves across the disk surface and, as a result, provides the uniform DFH efficiency. At the same time, the projecting wings and adjacent topology help to direct the airflow around the micro-pad and provide the stable flying height.
    Type: Grant
    Filed: August 13, 2008
    Date of Patent: June 28, 2011
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Xinjiang Shen, Zhu Feng, Ellis Cha, Robert Chu
  • Patent number: 7961433
    Abstract: A slider is formed with an ABS topography that eliminates the accumulation of lubricant swept from the surface of a rotating disk in an operating HDD. The topography includes air channeling grooves in which are formed backflow blocking elements that prevent the formation airflow patterns that would cause lubricant to be aspirated into the ABS topography of the slider and that create airflow patterns that sweep lubricant away from the ABS of the slider. The topography is first tested to make sure that the slider has the proper flying height and aerodynamic stability, then the backflow blocking elements are added to control the airflow, while maintaining the desired flying height and stability.
    Type: Grant
    Filed: February 29, 2008
    Date of Patent: June 14, 2011
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Guoqiang Zheng, Shoji Toyoda, Ellis Cha, Zhu Feng, Collins Lee
  • Patent number: 7894162
    Abstract: A slider mounted read/write head is protected from thermal asperities due to head-disk interactions by a ridge formed along an interfacial plane that extends above the ABS plane of the slider. The ridge is formed as part of a lapping process that is directed from the read/write head towards the slider substrate and uses an abrasive slurry to which may be added a strong base such as KOH. The height of the ridge is less than approximately 2 nm.
    Type: Grant
    Filed: April 16, 2007
    Date of Patent: February 22, 2011
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Niraj Mahdev, Kasumaza Yasuda, Ellis Cha
  • Publication number: 20100172057
    Abstract: Gimbal designs are provided that minimize adverse dynamic performance of a HDD suspension, particularly subsequent to head-disk-interface (HDI) interactions. The improvement of operational performance can be seen in graphical representations of the vibrational modes of a gimbal mounted slider subsequent to such HDI interactions. Each gimbal design includes a ramp limiter formed as two separated arms connected by one or two transverse bars and a routing of conducting traces that relieves stress and minimally contacts these bars.
    Type: Application
    Filed: March 5, 2010
    Publication date: July 8, 2010
    Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
  • Patent number: 7701672
    Abstract: A loadbeam is locally stiffened by either, 1. the addition of strategically placed extra material to the loadbeam, 2. not removing material during the etching process to form the loadbeam, or 3. special forming, by crimping or bending, at specific sites on the beam. The use of local stiffening, when placed about the loadbeam dimple or between the dimple and flexure attachment points, with or without additional damping, can significantly improve the dynamical response of the loadbeam and eliminate vibrational modes of a slider mounted on the loadbeam during HDI interactions with disk surface asperities during disk drive operation.
    Type: Grant
    Filed: June 16, 2006
    Date of Patent: April 20, 2010
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
  • Patent number: 7684154
    Abstract: Gimbal designs are provided that minimize adverse dynamic performance of a HDD suspension, particularly subsequent to head-disk-interface (HDI) interactions. The improvement of operational performance can be seen in graphical representations of the vibrational modes of a gimbal mounted slider subsequent to such HDI interactions. Each gimbal design includes a ramp limiter formed as two separated arms connected by one or two transverse bars and a routing of conducting traces that relieves stress and minimally contacts these bars.
    Type: Grant
    Filed: August 1, 2006
    Date of Patent: March 23, 2010
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
  • Patent number: 7675711
    Abstract: A system and method for measuring and neutralizing the electrical charge at the interface of a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A surface treatment material is applied to the magnetic head. The surface treatment material matches the medium surface material on the surface of the magnetic storage medium. The surface treatment material on the magnetic read/write head may be a fluorinated carbon, such as a Fomblin Z-derivative, perfluoro alkyl trichlorosilane, a FC-722, or a fluorinated polymer. The surface treatment material can be applied to the magnetic head by a vapor deposition process or by a liquid immersion process. The charge on the head-disk interface can be measured by applying varying external charges to the head while reading a signal previously written to the disk.
    Type: Grant
    Filed: May 7, 2003
    Date of Patent: March 9, 2010
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Zhu Feng, Ellis Cha, Xiaofeng Zhang
  • Publication number: 20100039732
    Abstract: A DFH (Dynamic Flying Height) type slider ABS design has a stable flying height and a DFH efficiency that is uniform across the entire disk surface. These properties are a result of embedding the read/write head and heater in a trapezoidally bridged micro-pad having a very small surface area. The micro-pad is surrounded by a wing-like structure that projects from a central rail in the ABS and the micro pad is connected to an inner edge of that structure by a bridge having a trapezoidal shape. The trapezoidal shape responds effectively to variations in air flow direction and pressure point as the slider moves across the disk surface and, as a result, provides the uniform DFH efficiency. At the same time, the projecting wings and adjacent topology help to direct the airflow around the micro-pad and provide the stable flying height.
    Type: Application
    Filed: August 13, 2008
    Publication date: February 18, 2010
    Inventors: Xinjiang Shen, Zhu Feng, Ellis Cha, Robert Chu
  • Publication number: 20090262458
    Abstract: A DFH (Dynamic Flying Height) type slider ABS design has significantly improved DFH efficiency and a decreased sensitivity of flying height to both ambient conditions and disk surface variations. This is a result of embedding the read/write head and heater in a micro-pad having a very small surface area. The micro-pad is surrounded by a wing-like structure that projects from a central rail in the ABS. The micro-pad is separated from the central rail by a surrounding trench whose depth can be varied to tune the DFH efficiency. The small surface area of the micro-pad reduces the air pressure at the read/write head and the projecting wings and adjacent topology help to direct the airflow around the micro-pad.
    Type: Application
    Filed: April 21, 2008
    Publication date: October 22, 2009
    Inventors: Xinjiang Shen, Zhu Feng, Ellis Cha, Robert Chu
  • Publication number: 20090219651
    Abstract: A slider is formed with an ABS topography that eliminates the accumulation of lubricant swept from the surface of a rotating disk in an operating HDD. The topography includes air channeling grooves in which are formed backflow blocking elements that prevent the formation airflow patterns that would cause lubricant to be aspirated into the ABS topography of the slider and that create airflow patterns that sweep lubricant away from the ABS of the slider. The topography is first tested to make sure that the slider has the proper flying height and aerodynamic stability, then the backflow blocking elements are added to control the airflow, while maintaining the desired flying height and stability.
    Type: Application
    Filed: February 29, 2008
    Publication date: September 3, 2009
    Inventors: Guoqiang Zheng, Shoji Toyoda, Ellis Cha, Zhu Feng, Collins Lee
  • Publication number: 20090074949
    Abstract: A system and method for measuring and neutralizing the electrical charge at the interface of a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A surface treatment material is applied to the magnetic head. The surface treatment material matches the medium surface material on the surface of the magnetic storage medium. The surface treatment material on the magnetic read/write head may be a fluorinated carbon, such as a Fomblin Z-derivative, perfluoro alkyl trichlorosilane, a FC-722, or a fluorinated polymer. The surface treatment material can be applied to the magnetic head by a vapor deposition process or by a liquid immersion process. The charge on the head-disk interface can be measured by applying varying external charges to the head while reading a signal previously written to the disk.
    Type: Application
    Filed: November 20, 2008
    Publication date: March 19, 2009
    Applicant: SAE MAGNETICS (H.K.) LTD.
    Inventors: Zhu FENG, Ellis CHA, Xiaofeng ZHANG