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).
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Patent number: 8576671Abstract: 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: GrantFiled: December 7, 2012Date of Patent: November 5, 2013Assignees: SAE Magnetics (H.K) Ltd., Headway Technologies, Inc.Inventors: Ellis Cha, Ben Kwun Pan Ng
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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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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: 20130094104Abstract: 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: ApplicationFiled: October 17, 2011Publication date: April 18, 2013Inventors: Siu Yin Ngan, Qinghua Zeng, Ellis 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: 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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Publication number: 20110299196Abstract: 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: ApplicationFiled: August 15, 2011Publication date: December 8, 2011Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
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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: 8000061Abstract: 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: March 5, 2010Date of Patent: August 16, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
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Patent number: 7969685Abstract: 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: GrantFiled: August 13, 2008Date of Patent: June 28, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Xinjiang Shen, Zhu Feng, Ellis Cha, Robert Chu
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Patent number: 7961433Abstract: 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: GrantFiled: February 29, 2008Date of Patent: June 14, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Guoqiang Zheng, Shoji Toyoda, Ellis Cha, Zhu Feng, Collins Lee
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Patent number: 7894162Abstract: 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: GrantFiled: April 16, 2007Date of Patent: February 22, 2011Assignee: SAE Magnetics (HK) Ltd.Inventors: Niraj Mahdev, Kasumaza Yasuda, Ellis Cha
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Publication number: 20100172057Abstract: 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: ApplicationFiled: March 5, 2010Publication date: July 8, 2010Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
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Patent number: 7701672Abstract: 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: GrantFiled: June 16, 2006Date of Patent: April 20, 2010Assignee: SAE Magnetics (HK) Ltd.Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
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Patent number: 7684154Abstract: 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 1, 2006Date of Patent: March 23, 2010Assignee: SAE Magnetics (HK) Ltd.Inventors: Qinghua Zeng, Chao-Hui Yang, Yen Fu, Ellis Cha
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Patent number: 7675711Abstract: 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: GrantFiled: May 7, 2003Date of Patent: March 9, 2010Assignee: SAE Magnetics (HK) Ltd.Inventors: Zhu Feng, Ellis Cha, Xiaofeng Zhang
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Publication number: 20100039732Abstract: 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: ApplicationFiled: August 13, 2008Publication date: February 18, 2010Inventors: Xinjiang Shen, Zhu Feng, Ellis Cha, Robert Chu
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Publication number: 20090262458Abstract: 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: ApplicationFiled: April 21, 2008Publication date: October 22, 2009Inventors: Xinjiang Shen, Zhu Feng, Ellis Cha, Robert Chu
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Publication number: 20090219651Abstract: 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: ApplicationFiled: February 29, 2008Publication date: September 3, 2009Inventors: Guoqiang Zheng, Shoji Toyoda, Ellis Cha, Zhu Feng, Collins Lee
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Publication number: 20090074949Abstract: 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: ApplicationFiled: November 20, 2008Publication date: March 19, 2009Applicant: SAE MAGNETICS (H.K.) LTD.Inventors: Zhu FENG, Ellis CHA, Xiaofeng ZHANG