Patents by Inventor Tsutomu Tom Yamashita

Tsutomu Tom Yamashita 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: 6855232
    Abstract: A method for making a magnetic disk comprises forming first and second protective carbon layers on a magnetic layer. The first protective carbon layer is predominantly SP3 carbon. The second protective carbon layer comprises about 50% or less SP3 carbon. The second protective carbon layer is very thin, e.g. between 0.1 and 1.0 nm thick. A lubricant layer (e.g. a perfluoropolyether lubricant) is applied to the second protective carbon layer. The second protective carbon layer facilitates improved cooperation between lubricant and the disk.
    Type: Grant
    Filed: December 5, 2003
    Date of Patent: February 15, 2005
    Assignee: Komag, Inc.
    Inventors: Bruce Jairson, Ching Jackie Tsoi, Wen Liu, Shigeto Hashimoto, Eric Woo Hock Yong, Tsutomu Tom Yamashita
  • Publication number: 20040137207
    Abstract: A method for making a magnetic disk comprises forming first and second protective carbon layers on a magnetic layer. The first protective carbon layer is predominantly SP3 carbon. The second protective carbon layer comprises about 50% or less SP3 carbon. The second protective carbon layer is very thin, e.g. between 0.1 and 1.0 nm thick. A lubricant layer (e.g. a perfluoropolyether lubricant) is applied to the second protective carbon layer. The second protective carbon layer facilitates improved cooperation between lubricant and the disk.
    Type: Application
    Filed: December 5, 2003
    Publication date: July 15, 2004
    Inventors: Bruce Lairson, Ching Jackie Tsoi, Wen Liu, Shigeto Hashimoto, Eric Woo Hock Yong, Tsutomu Tom Yamashita
  • Patent number: 6682807
    Abstract: A method for making a magnetic disk comprises forming first and second protective carbon layers on a magnetic layer. The first protective carbon layer is predominantly SP3 carbon. The second protective carbon layer comprises about 50% or less SP3 carbon. The second protective carbon layer is very thin, e.g. between 0.1 and 1.0 nm thick. A lubricant layer (e.g. a perfluoropolyether lubricant) is applied to the second protective carbon layer. The second protective carbon layer facilitates improved cooperation between lubricant and the disk.
    Type: Grant
    Filed: September 26, 2002
    Date of Patent: January 27, 2004
    Assignee: Komag, Inc.
    Inventors: Bruce Lairson, Ching Jackie Tsoi, Wen Liu, Shigeto Hashimoto, Eric Woo Hock Yong, Tsutomu Tom Yamashita
  • Patent number: 6565719
    Abstract: A method for making a magnetic disk comprises forming first and second protective carbon layers on a magnetic layer. The first protective carbon layer is predominantly SP3 carbon. The second protective carbon layer comprises about 50% or less SP3 carbon. The second protective carbon layer is very thin, e.g. between 0.1 and 1.0 nm thick. A lubricant layer (e.g. a perfluoropolyether lubricant) is applied to the second protective carbon layer. The second protective carbon layer facilitates improved cooperation between lubricant and the disk.
    Type: Grant
    Filed: June 27, 2000
    Date of Patent: May 20, 2003
    Assignee: Komag, Inc.
    Inventors: Bruce Lairson, Ching Jackie Tsoi, Wen Liu, Shigeto Hashimoto, Eric Woo Hock Yong, Tsutomu Tom Yamashita
  • Publication number: 20030027019
    Abstract: A method for making a magnetic disk comprises forming first and second protective carbon layers on a magnetic layer. The first protective carbon layer is predominantly SP3 carbon. The second protective carbon layer comprises about 50% or less SP3 carbon. The second protective carbon layer is very thin, e.g. between 0.1 and 1.0 nm thick. A lubricant layer (e.g. a perfluoropolyether lubricant) is applied to the second protective carbon layer. The second protective carbon layer facilitates improved cooperation between lubricant and the disk.
    Type: Application
    Filed: September 26, 2002
    Publication date: February 6, 2003
    Inventors: Bruce Lairson, Ching Jackie Tsoi, Wen Liu, Shigeto Hashimoto, Eric Woo Hock Yong, Tsutomu Tom Yamashita
  • Patent number: 6117499
    Abstract: A method of manufacturing a magnetic disk comprises the steps of: a) providing a substrate with a layer of an amorphous multi-component material at its surface; b) irradiating the amorphous layer (e.g. by applying heat from a heating element, laser beam, or the like) to thereby create micro-structurally changed regions in the amorphous layer; and c) chemo-mechanically polishing the amorphous layer to produce micro-texture features at or near the micro-structurally changed regions. The disk is then completed by depositing additional layers such as an underlayer, a magnetic layer, a protective overcoat, etc.
    Type: Grant
    Filed: April 9, 1998
    Date of Patent: September 12, 2000
    Assignee: Komag, Inc.
    Inventors: Javier Wong, Li-Ju Judy Lin, Douglas Allan Iams, Hongchuan Wong, Tsutomu Tom Yamashita
  • Patent number: 6013161
    Abstract: A Co--Pt based magnetic alloy which has been doped with a relatively high amount of nitrogen, e.g., at or above 1 at. % is obtained having high coercivity, for example in the range of 1400 Oe or above, and an increased signal-to-noise ratio as compared to the same Co--Pt based alloy which has not been doped with nitrogen. The alloy is vacuum deposited, for example, by sputtering, and the nitrogen may be introduced from the sputtering gas or from the sputtering target. Other low-solubility elements providing the grain uniformity and isolation include: B, P, S, C, Si, As, Se and Te.
    Type: Grant
    Filed: October 28, 1997
    Date of Patent: January 11, 2000
    Assignee: Komag, Incorporated
    Inventors: Tu Chen, Tsutomu Tom Yamashita, John Ko-Jen Chen, Rajiv Yadav Ranjan, Keith Kadokura, Ting Joseph Yuen
  • Patent number: 5976326
    Abstract: A Co--Pt based magnetic alloy which has been sputtered with an oxide or nitride of a primary constituent of the magnetic layer, e.g., CoO below about 10 at. %, provides improved coercivity, squareness, and reduced noise as compared to magnetic alloys with oxygen introduced by other methods. The alloy is vacuum deposited, for example, by sputtering, and the oxide or nitride may be introduced from the sputtering target from which the magnetic layer materials come or from a separate sputtering target. Examples of such oxides and nitrides include CoO, Co.sub.2 0.sub.3, Co.sub.3 O.sub.4, CrO.sub.2, Cr.sub.2 O.sub.3, TiO.sub.2, Ta.sub.2 O.sub.5, Al.sub.2 O.sub.3, WO, CoN, Co.sub.2 N, TiN, TaN, CrN, NiN, etc.
    Type: Grant
    Filed: August 28, 1997
    Date of Patent: November 2, 1999
    Assignee: Komag, Incorporated
    Inventors: Rajiv Yadav Ranjan, Miaogen Lu, Tsutomu Tom Yamashita, Tu Chen
  • Patent number: 5908514
    Abstract: A new magnetic alloy exhibits high Hc and Ms while exhibiting excellent corrosion resistance, thereby providing ideal physical properties for high density recording applications. Other parameters of the media, such as SNR, PW50, and S are at least maintained, if not also improved. The alloy contains cobalt and up to 10 at. % Ni, up to 20 at. % Pt, up to 10 at. % Ta, up to 10 at. % Ti, and optionally up to 6 at. % B. The ratio of the tantalum to titanium in the alloy is between 3:1 and 1:3. The alloy is deposited by vacuum deposition (typically sputtering) on a similarly deposited non-magnetic alloy under layer. Nitrogen and/or oxygen may be introduced into the alloy during deposition to improve SNR. Other corrosion-resistant thin film alloys may also be obtained by the inclusion of Ta and Ti.
    Type: Grant
    Filed: October 24, 1996
    Date of Patent: June 1, 1999
    Inventors: Rajiv Yadav Ranjan, Tu Chen, Tsutomu Tom Yamashita, John Ko-Jen Chen
  • Patent number: 5851688
    Abstract: A Co--Pt based magnetic alloy which has been doped with a relatively high amount of nitrogen, e.g., at or above 1 at. % is obtained having high coercivity, for example in the range of 1400 Oe or above, and an increased signal-to-noise ratio as compared to the same Co--Pt based alloy which has not been doped with nitrogen. The alloy is vacuum deposited, for example, by sputtering, and the nitrogen may be introduced from the sputtering gas or from the sputtering target. Other low-solubility elements providing the grain uniformity and isolation include: B, P, S, C, Si, As, Se and Te.
    Type: Grant
    Filed: November 20, 1997
    Date of Patent: December 22, 1998
    Assignee: Komag, Inc.
    Inventors: Tu Chen, Tsutomu Tom Yamashita, John Ko-Jen Chen, Rajiv Yadav Ranjan, Keith Kadokura, Ting Joseph Yuen
  • Patent number: 5736013
    Abstract: A Co--Pt based magnetic alloy which has been sputtered with an oxide or nitride of a primary constituent of the magnetic layer, e.g., CoO below about 10 at. %, provides improved coercivity, squareness, and reduced noise as compared to magnetic alloys with oxygen introduced by other methods. The alloy is vacuum deposited, for example, by sputtering, and the oxide or nitride may be introduced from the sputtering target from which the magnetic layer materials come or from a separate sputtering target. Examples of such oxides and nitrides include CoO, Co.sub.2 O.sub.3, Co.sub.3 O.sub.4, CrO.sub.2, Cr.sub.2 O.sub.3, TiO.sub.2, Ta.sub.2 O.sub.5, Al.sub.2 O.sub.3, WO, CoN, Co.sub.2 N, TiN, TaN, CrN, NiN, etc.
    Type: Grant
    Filed: January 3, 1997
    Date of Patent: April 7, 1998
    Assignee: Komag, Inc.
    Inventors: Rajiv Yadav Ranjan, Miaogen Lu, Tsutomu Tom Yamashita, Tu Chen
  • Patent number: 5695387
    Abstract: Definition of the required geometry of the air bearing surface ("ABS") of a magnetic head slider is achieved while providing an ABS which exhibits low wear, low friction, and low stiction at its interface with a disk surface, by securely embedding monocrystalline diamond particles into a lapping plate, removing substantially all particles from the plate which are not firmly affixed thereto, and lapping the slider in a linear, X-Y direction at a relatively high lapping pressure. Material susceptible to being dislodged during CSS is removed during the lapping process. Thus, the incidence of material dislodging from the ABS and increasing wear-induced stiction is substantially reduced, resulting in improved CSS performance. A desired microtexture is also applied to the ABS. Reduced pole tip recession is also observed.
    Type: Grant
    Filed: February 21, 1995
    Date of Patent: December 9, 1997
    Assignee: Komag, Inc.
    Inventors: Mark D. Moravec, Tu Chen, Tracy L. Scott, Kyou Haeng Lee, Tsutomu Tom Yamashita, Tam Huu-Minh Nguyen
  • Patent number: 5673156
    Abstract: A hard disk drive utilizing a combination of thin film recording heads and media allows high density recording through virtual contact recording, while still providing excellent contact start stop performance and low stiction. The air bearing surface of the head has a microscopically fine texture which provides reliable mechanical performance with a constant and very low flying height. A skew insensitive constant flying height over the disk surface can be provided with the use of transverse pressure contour or cross-cut slider designs. The slider air bearing surface is textured by selective mechanical removal of subsurface damaged regions left behind during the diamond lapping of the slider air bearing surface, thereby leaving the slider less abrasive to the disk. A slider with this fine texture on the air bearing surface permits the use of a much smoother texture and thinner overcoat on the disk than currently possible using conventional sliders.
    Type: Grant
    Filed: February 17, 1995
    Date of Patent: September 30, 1997
    Assignee: Komag, Inc.
    Inventors: Tu Chen, Tsutomu Tom Yamashita, Kyou H. Lee, Yasuo Sakane
  • Patent number: 5658659
    Abstract: Media according to the present invention is comprised of individual magnetic grains as small as 300 .ANG. or smaller in diameter, which are uniformly spaced apart by a distance between 5 and 50 .ANG. by a solid segregant. This media will typically exhibit coercivity and remanent coercivity squareness of at least 0.8 each, a switching field distribution of less than 0.2, and a coercivity of at least 1500 Oe (with a minimum required Pt content), while simultaneously providing the lowest media jitter noise for optimum magnetic performance. The media is deposited at a low partial pressure of water and in the presence of an optimum amount of contributant gas on a doped nucleation layer for grain growth control.
    Type: Grant
    Filed: August 5, 1994
    Date of Patent: August 19, 1997
    Assignee: Komag, Inc.
    Inventors: Tu Chen, Rajiv Yadav Ranjan, Tsutomu Tom Yamashita, Miaogen Lu, Keith Kadokura, John Ko-Jen Chen, Ting Joseph Yuen
  • Patent number: RE37748
    Abstract: A Co-Pt based magnetic alloy which has been doped with a relatively high amount of nitrogen, e.g., or above 1 at. % is obtained having high coercivity, for example in the range of 1400 Oe or above, and an increased signal-to-noise ratio as compared to the same Co-Pt based alloy which has not been doped with nitrogen. The alloy is vacuum deposited, for example, by sputtering, and the nitrogen may be introduced from the sputtering gas or from the sputtering target.
    Type: Grant
    Filed: July 17, 2000
    Date of Patent: June 18, 2002
    Assignee: Komag, Inc.
    Inventors: Tu Chen, Tsutomu Tom Yamashita, Rajiv Yadav Ranjan, John Ko-Chen Chen, Keith Kadokura, Ting Joseph Yuen
  • Patent number: RE38544
    Abstract: A Co-Pt based magnetic alloy which has been doped with a relatively high amount of nitrogen, e.g., or above 1 at. % is obtained having high coercivity, for example in the range of 1400 Oe or above, and an increased signal-to-noise ratio as compared to the same Co-Pt based alloy which has not been doped with nitrogen. The alloy is vacuum deposited, for example, by sputtering, and the nitrogen may be introduced from the sputtering gas or from the sputtering target. Other low-solubility elements providing the grain uniformity and isolation include: B, P, S, C, Si, As, Se and Te.
    Type: Grant
    Filed: July 17, 2000
    Date of Patent: July 6, 2004
    Assignee: Komag, Inc.
    Inventors: Tu Chen, Tsutomu Tom Yamashita, Rajiv Yadav Ranjan, John Ko-Chen Chen, Keith Kadokura, Ting Joseph Yuen