Patents Assigned to SAE Magnetics (HK)
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Patent number: 9940960Abstract: A slider design for a hard disk drive (HDD) features an air-bearing surface (ABS) topography with arrays of micro-dots formed on bases of a multiplicity of cavities at different depths. The design eliminates the accumulation of hydrocarbons (e.g., spindle oil and disk lubricant) deposits in regions of air stagnation within the cavities where backflows and foreflows of air meet and cancel during HDD operation. The micro-dots are small raised regions of various shapes having sizes and spacings in the range between 2 and 100 microns and, in a preferred embodiment, heights of 0.15 microns above the cavity bases.Type: GrantFiled: May 24, 2016Date of Patent: April 10, 2018Assignees: SAE Magnetics (HK) Ltd., Headway Technologies, Inc.Inventors: Ellis Cha, Sindy Yeung, Penny Wan Ting Looi, Ben Kwun Pan Ng
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Patent number: 9251829Abstract: 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: GrantFiled: October 17, 2011Date of Patent: February 2, 2016Assignees: SAE Magnetics (HK) Ltd., Headway Technologies, Inc.Inventors: Siu Yin Ngan, Qinghua Zeng, Ellis Cha
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Patent number: 8976481Abstract: Methods are provided for determining the heater power level of a dynamic flying height (DFH) type write head at which a touch down (TD) occurs. Each method makes use of the DC component of a head-disk interference (HDI) sensor and the determination of the TD heater energy is deduced from certain characteristics of the function relating heater power to HDI DC signal strength. Characteristics that provide reliable indication of a TD include points of minimum slope, structure of the slope's slope and the properties of a linear fit to the slope if the slope does not converge to a consistent value. It is found that the use of all methods in combination allow a reliable TD determination under virtually all conditions.Type: GrantFiled: February 18, 2014Date of Patent: March 10, 2015Assignees: SAE Magnetics (HK) Ltd., Headway Technologies, Inc.Inventors: Qinghua Zeng, Ellis Cha, Soramany Ka
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Patent number: 8867172Abstract: A DFH (Dynamic Flying Height) type slider ABS design has significantly improved DFH efficiency and back-off efficiency as well as uniform touchdown detectability. This is the result of decoupling the local pressure variations at the read/write head that result from skew angle variations across a disk, from local stiffness due to ABS protrusion caused by heater activation. The decoupling, which allows the heater activation stiffness to be carefully tuned, is a result of the effects of airflow channeled by a wide down-track channel onto a narrow down-track channel formed in an extended finger of the central pad of the slider. Airflow impinges on the finger channel in a manner that eliminates variations in air pressure at the central pad due to variations in skew angle.Type: GrantFiled: July 31, 2012Date of Patent: October 21, 2014Assignees: SAE Magnetics (HK) Ltd., Headway Technologies, Inc.Inventors: Guoqiang Zheng, Wan Ting Looi, Kwun Pan Ng, Ellis Cha
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Patent number: 8767339Abstract: 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: GrantFiled: March 20, 2012Date of Patent: July 1, 2014Assignee: SAE Magnetics (HK) Ltd.Inventors: Qinghua Zeng, Ellis Cha
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Patent number: 8717702Abstract: 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: GrantFiled: March 20, 2012Date of Patent: May 6, 2014Assignees: SAE Magnetics (HK) Lid., Headway Technologies, Inc.Inventors: Qinghua Zeng, Ellis Cha, Soramany Ka
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Publication number: 20130250455Abstract: 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: ApplicationFiled: March 20, 2012Publication date: September 26, 2013Applicants: HEADWAY TECHNOLOGIES, INC., SAE MAGNETICS (HK) LTD.Inventors: Qinghua Zeng, Ellis Cha, Soramany Ka
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Publication number: 20130250446Abstract: 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: ApplicationFiled: March 20, 2012Publication date: September 26, 2013Applicants: HEADWAY TECHNOLOGIES, INC., SAE MAGNETICS (HK) LTD.Inventors: Qinghua Zeng, Ellis Cha
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Patent number: 8331059Abstract: A bracket for a hard disc drive combining three separate functions, a ramp, a latch and a connector bracket into a single assembly. The bracket assembly, mounted with ramp and latch, secures and seals the electrical connector connecting the flexible printed circuit on the head side of the actuator. Traditionally, latches are on the coil side of the actuator. Moreover, the combination bracket improves manufacturability while reducing overall cost for the disc drive. The assembly can be purchased complete from a supplier.Type: GrantFiled: May 20, 2009Date of Patent: December 11, 2012Assignee: SAE Magnetics (HK) Ltd.Inventor: Stephen Ralph Viskochil
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Patent number: 8274751Abstract: A system and method for measuring the modulation between a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A magnetic read/write head is positioned above a magnetic storage medium at a given flying height. The magnetic read/write head reads a signal from the magnetic storage medium. A tester measures an alternating electric current between the magnetic read/write head through the slider and the magnetic storage medium. A computer may then calculate the modulation by the magnetic read/write head based on the alternating electric current. A DC voltage to the head may be applied to lower the flying height of the magnetic head.Type: GrantFiled: April 1, 2011Date of Patent: September 25, 2012Assignee: SAE Magnetics (HK) Ltd.Inventors: Zhu Feng, Xiaofeng Zhang, Ellis T. Cha
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Patent number: 8218269Abstract: 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: GrantFiled: August 15, 2011Date of Patent: July 10, 2012Assignee: SAE Magnetics (HK) Ltd.Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
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Patent number: 8189296Abstract: A method includes a step of stacking a first electrode layer, a piezoelectric layer, and a second electrode layer on a first substrate to form a first laminate; a step of stacking a support layer on a second substrate to form a second laminate; a step of bonding the first and second laminates through an adhesive layer to form a third laminate; a step of removing the first substrate from the third laminate; a step of processing the third laminate in a desired shape; and a step of removing the second substrate. A Young's modulus of the adhesive layer is smaller than a Young's modulus of the piezoelectric layer. Respective Young's moduli of the second electrode layer and the support layer are larger than the Young's modulus of the adhesive layer. The third laminate has no other piezoelectric layer except for the aforementioned piezoelectric layer.Type: GrantFiled: October 15, 2009Date of Patent: May 29, 2012Assignees: TDK Corporation, SAE Magnetics (HK), Ltd.Inventors: Kenjiro Hata, Hirofumi Sasaki, Katsuyuki Kurachi
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Patent number: 8184405Abstract: 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: GrantFiled: January 14, 2011Date of Patent: May 22, 2012Assignee: SAE Magnetics (HK) Ltd.Inventors: Guoqiang Zheng, Ellis Cha, Zhu Feng, Sindy Yeung
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Patent number: 8139306Abstract: A system and method for measuring the modulation between a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A magnetic read/write head is positioned above a magnetic storage medium at a given flying height. The magnetic read/write head reads a signal from the magnetic storage medium. A tester measures an alternating electric current between the magnetic read/write head through the slider and the magnetic storage medium. A computer may then calculate the modulation by the magnetic read/write head based on the alternating electric current. A DC voltage to the head may be applied to lower the flying height of the magnetic head.Type: GrantFiled: November 4, 2004Date of Patent: March 20, 2012Assignee: SAE Magnetics (HK) Ltd.Inventors: Zhu Feng, Xiaofeng Zhang, Ellis T. Cha
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Patent number: 8107200Abstract: A slider mounted CPP GMR or TMR read head sensor is protected from electrostatic discharge (ESD) damage and from noise and cross-talk from an adjacent write head by means of a balanced resistive/capacitative shunt. The shunt includes highly resistive interconnections between upper and lower shields of the read head and a grounded slider substrate and a low resistance interconnection between the lower pole piece of the write head and the substrate. The capacitances between the pole piece and the upper shield, the upper shield and the lower shield and the lower shield and the substrate are made equal by either forming the shields and pole piece with equal surface areas and separating them with dielectrics of equal thicknesses, or by keeping the ratio of area to insulator thicknesses equal.Type: GrantFiled: June 19, 2008Date of Patent: January 31, 2012Assignees: Headway Technologies, Inc., SAE Magnetics (HK) Ltd.Inventors: Eric Cheuk Wing Leung, Anthony Wai Yuen Lai, Pak Kin Wong, David Hu, Moris Dovek, Rod Lee
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Patent number: 8054585Abstract: 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: GrantFiled: November 28, 2006Date of Patent: November 8, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Qinghua Zeng, Yen Fu, Ellis Cha
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Patent number: 8045295Abstract: Method and apparatus are presented for electrically coupling a slider to ground. In one embodiment, a bonding pad is provided on a side of the slider body separate from the bonding pad(s) used for read/write signals. This separate bonding pad is electrically coupled within the slider body to components that are to be coupled to ground. A separate conductor provided on the suspension (e.g., a trace, a flex circuit, etc.) may be electrically coupled to the separate bonding pad via gold ball bonding. The conductor is also coupled to ground in the hard-disk drive device (e.g., via the preamplifier). The use of the separated bonding pad and trace may negate the need to use a conductive adhesive to electrically ground the slider via its attachment to the tongue of a slider.Type: GrantFiled: June 24, 2008Date of Patent: October 25, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Yen Fu, Ellis T. Cha, Po-Kang Wang, Hong Tian, Manuel Hernandez, Yaw-Shing Tang, Ben Hu
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Patent number: 8027127Abstract: In a balanced head gimbal assembly for improved seeking performance, a slider having a magnetic head with a set of read elements to read data and a set of write elements to write data, an air-bearing surface, and a non-air-bearing surface is coupled to a suspension. The suspension includes a loadbeam, a flexure, and a balancing weight. The loadbeam is coupled to an actuator arm. The flexure, coupled to the loadbeam, has a window through which a dimple, coupled to the loadbeam, contacts a dimple contact point. The balancing weight, coupled to the flexure, has a configuration which permits alignment of a center of mass of the head gimbal assembly with the dimple contact point.Type: GrantFiled: February 28, 2011Date of Patent: September 27, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Qinghua Zeng, Yen Fu, Li-Yan Zhu, Chao-Hui Yang, Ellis T. Cha
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Patent number: 8018682Abstract: A magnetic disk is protected by a bilayer. The bilayer is formed as an adhesion enhancing underlayer and a protective diamond-like carbon (DLC) overlayer. The underlayer is formed of an aluminum or alloyed aluminum oxynitride, having the general formula AlOxNy or MezAlOxNy where Mez symbolizes Tiz, Siz or Crz and where x, y and z can be varied within the formation process. By adjusting the values of x and y the adhesion underlayer contributes to such qualities of the protective bilayer as stress compensation, chemical and mechanical stability and low electrical conductivity. Various methods of forming the underlayer are provided, including reactive ion sputtering, plasma assisted chemical vapor deposition, pulsed laser deposition and plasma immersion ion implantation.Type: GrantFiled: August 2, 2010Date of Patent: September 13, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Shide Cheng, Zhu Feng, Ellis T. Cha
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Patent number: 8014104Abstract: A protective bilayer on a magnetic read/write head or magnetic disk is formed as an adhesion enhancing and corrosion resistant underlayer and a protective diamond-like carbon (DLC) overlayer. The underlayer is a transition metal oxynitride, having the general formula MeOxNy, where Me represents a single element or an alloy of the following transition metal elements: Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, here x can be within the range between 0 and 3 and y is in the range between approximately 0 and 2. Adjusting the values of x and y contributes to such qualities of the protective bilayer as stress compensation, chemical and mechanical stability and low electrical conductivity. Methods of forming the adhesion layer, include reactive ion sputtering, plasma assisted chemical vapor deposition, pulsed laser deposition and plasma immersion ion implantation.Type: GrantFiled: March 21, 2007Date of Patent: September 6, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Shide Cheng, Zhu Feng, Ellis T. Cha