Patents by Inventor Masafumi Mochizuki

Masafumi Mochizuki 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: 20060082924
    Abstract: Embodiments of the invention are directed to narrowing a read/write gap of a perpendicular magnetic head by applying a wrap around shield, data erasing from return pole edges by returning recording field, and reducing TPR of a magnetic material. In one embodiment, the wrap around shields are formed by partitioning and making Gd, which is the height of the shield at the main pole side in the sensor height direction, smaller than the height of the shield connected to the return pole in the sensor height direction.
    Type: Application
    Filed: October 18, 2005
    Publication date: April 20, 2006
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kimitoshi Etoh, Masafumi Mochizuki, Isao Nunokawa, Tomohiro Okada
  • Patent number: 7031108
    Abstract: A magnetic head is composed to diminish disordered writing bits of a recording layer or reading noise caused by a magnetic field generated from an under layer without decreasing a writing magnetic field strength of the magnetic head. The magnetic head includes a write head provided with a main pole and one or more auxiliary poles, a read head provided with a read element, and coils located on both sides of the main pole in a manner to sandwich the main pole. The coil located on one side generates the asymmetrical magneto-motive force for magnetizing the main pole to that generated by the coil located on the other side.
    Type: Grant
    Filed: May 23, 2005
    Date of Patent: April 18, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Masafumi Mochizuki, Atsushi Nakamura, Yoji Maruyama
  • Patent number: 7027248
    Abstract: In a thermal assisted type magnetic disk apparatus having a head holding a heat element and a write element, in which coercivity of a disk is locally reduced by temperature-increasing the disk and writing is performed by the write element, along with a seek operation to move the head by a rotary actuator in a radial direction, a yaw angle is changed and a heat area and the write element are track-shifted. A mechanism to offset one of the heat area and the write element in a width direction of a slider, to array the heat element and the write element in a track running direction in correspondence with the yaw angle of the head.
    Type: Grant
    Filed: August 5, 2003
    Date of Patent: April 11, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Takehiko Hamaguchi, Atsushi Nakamura, Yasutaka Nishida, Masafumi Mochizuki, Hideki Sawaguchi
  • Patent number: 7024617
    Abstract: In a partial-response maximum-likelihood (PRML) signal detection and processing technique, reduction of data detection error events caused due to medium noise is achieved. For a PRML detection data result obtained after PRML data demodulation, a code error event that depends on a signal distance, and which has a high frequency of occurrences, is noticed and its occurrence probability is estimated. A locally-existing medium noise quantity is estimated from preceding and subsequent code patterns of the PRML detection data result. Based on this, the occurrence probability of the error event is compensated to improve the detection precision. As a result, data modulation with reliability higher than conventional maximum likelihood detection can be realized with a simple circuit structure.
    Type: Grant
    Filed: July 29, 2002
    Date of Patent: April 4, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Masafumi Mochizuki, Hiroyuki Tsuchinaga
  • Patent number: 6995949
    Abstract: A magnetic head includes a main pole having a first portion with a length (W1) in a cross-track direction which continuously increases from a leading edge side to a trailing edge side, a second portion formed on a trailing edge side of the first portion, and a third portion formed on a trailing edge side of the second portion. A length (W2) in the cross-track direction of a boundary line between the second portion and the third portion is longer than W1, and a length (W3) in the cross-track direction of a trailing edge of a third portion is substantially equal to W2.
    Type: Grant
    Filed: April 28, 2005
    Date of Patent: February 7, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20060002018
    Abstract: Embodiments of the invention provide a magnetic head which prevents data on a recording medium from being erased even when a stray field is applied. In one embodiment, an auxiliary pole is sandwiched between a stray-field shield composed of a magnetic layer recessed from the air bearing surface and a main pole. The stray-field shield may be formed on the leading side of the auxiliary pole. A face of the stray-field shield on a medium side may be recessed from an air-bearing-surface of the magnetic head.
    Type: Application
    Filed: June 30, 2005
    Publication date: January 5, 2006
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hiroshi Fukui, Masafumi Mochizuki, Kaori Suzuki
  • Patent number: 6952380
    Abstract: A vertical magnetic recording apparatus is provided which can diminish thermal decay of magnetization to ensure a high reliability of the life of recorded information and which can stably effect the write of magnetic information. Light assist is performed by obliquely applying light to a gap between a main pole of a vertical recording head and a medium. The light is radiated from the head side of the apparatus with respect to the medium. Utilizing the present invention, the thermal decay of magnetization at room temperature is diminished, the life of the recorded information is increased, and the storage reliability of the disk is increased.
    Type: Grant
    Filed: May 6, 2002
    Date of Patent: October 4, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Fumio Isshiki, Atsuko Kuroda, Takayuki Ichihara, Masafumi Mochizuki, Takuya Matsumoto
  • Publication number: 20050213244
    Abstract: A magnetic head is composed to diminish disordered writing bits of a recording layer or reading noise caused by a magnetic field generated from an under layer without decreasing a writing magnetic field strength of the magnetic head. The magnetic head includes a write head provided with a main pole and one or more auxiliary poles, a read head provided with a read element, and coils located on both sides of the main pole in a manner to sandwich the main pole. The coil located on one side generates the asymmetrical magneto-motive force for magnetizing the main pole to that generated by the coil located on the other side.
    Type: Application
    Filed: May 23, 2005
    Publication date: September 29, 2005
    Inventors: Masafumi Mochizuki, Atsushi Nakamura, Yoji Maruyama
  • Publication number: 20050207061
    Abstract: A magnetic head is composed to diminish disordered writing bits of a recording layer or reading noise caused by a magnetic field generated from an under layer without decreasing a writing magnetic field strength of the magnetic head. The magnetic head includes a write head provided with a main pole and one or more auxiliary poles, a read head provided with a read element, and coils located on both sides of the main pole in a manner to sandwich the main pole. The coil located on one side generates the asymmetrical magneto-motive force for magnetizing the main pole to that generated by the coil located on the other side.
    Type: Application
    Filed: May 23, 2005
    Publication date: September 22, 2005
    Inventors: Masafumi Mochizuki, Atsushi Nakamura, Yoji Maruyama
  • Publication number: 20050185335
    Abstract: A magnetic head includes a main pole having a first portion with a length (W1) in a cross-track direction which continuously increases from a leading edge side to a trailing edge side, a second portion formed on a trailing edge side of the first portion, and a third portion formed on a trailing edge side of the second portion. A length (W2) in the cross-track direction of a boundary line between the second portion and the third portion is longer than W1, and a length (W3) in the cross-track direction of a trailing edge of a third portion is substantially equal to W2.
    Type: Application
    Filed: April 28, 2005
    Publication date: August 25, 2005
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20050157424
    Abstract: A thin film magnetic head for perpendicular recording of a single-pole type has a flux enhanced part and a flux enhanced end arranged on a leading side of the main pole parallel with the cross track direction. The side surface of the main pole intersecting the cross track direction is arranged on the track center side perpendicular to the track width. The field gradient of a perpendicular magnetic field on the trailing side of the main pole and near both ends of the track is made steep to realize a higher areal recording density. The head is fabricated by forming a first resist pattern on an inorganic insulating layer. A slope is formed on the inorganic insulating layer with the resist pattern as a mask. A second resist pattern is then formed on the inorganic insulating layer to form a magnetic layer on the inorganic insulating layer.
    Type: Application
    Filed: March 15, 2005
    Publication date: July 21, 2005
    Inventors: Atsuko Kuroda, Masafumi Mochizuki
  • Publication number: 20050141142
    Abstract: Embodiments of the invention provide a write head for perpendicular recording in which the magnetic field intensity applied at a read element is reduced with larger write-field gradients and the distance between a write element and a read element is small. In one embodiment, a pair of magnetic bodies for shielding a read element are provided on the leading and trailing sides of the read element respectively and whichever one of the two shields is the longer in the length from the air bearing surface is shorter than the length up to the back contact position PBK at which a main pole and an auxiliary pole are connected.
    Type: Application
    Filed: December 15, 2004
    Publication date: June 30, 2005
    Applicant: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Masafumi Mochizuki, Kaori Suzuki, Kimitoshi Etoh
  • Publication number: 20050141137
    Abstract: Embodiments of the invention provide a perpendicular magnetic writing head with a suppressed effective track width to be written on a magnetic medium while increasing writing magnetic field gradient. In one embodiment a trailing side shield is disposed by way of a gap film to a main pole of a perpendicular writing magnetic head. A gap distance (Gt) on a trailing side of the main pole and a gap distance (Gs) on a lateral side of the main pole is defined as Gt<Gt, and a thickness (Gd) from an air bearing surface of the shield is made equal to or less than a throat height. Alternatively, the thickness of Gd on the side of the main pole is reduced to less than that on the trailing side of the main pole. Further, for preventing defoliation of the shield upon fabrication of the air bearing surface, a thickness for a portion away from the main pole is increased.
    Type: Application
    Filed: December 14, 2004
    Publication date: June 30, 2005
    Applicant: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Tomohiro Okada, Isao Nunokawa, Masafumi Mochizuki
  • Patent number: 6891697
    Abstract: A magnetic head having at least a main pole having a profile on a magnetic head air bearing surface composed of a first portion having a length in a cross-track direction which continuously increases from a leading edge to a trailing edge, and a second portion located on the side of the trailing edge of the first portion. A length of the second portion in the cross-track direction at the trailing edge is substantially equal to a length in the cross-track direction at the point of contact between the first and second portions. A rate of change in the length of the second portion in the cross-track direction from the leading edge to the trailing edge is different from a rate of increase in the length of the first portion in the cross-track direction.
    Type: Grant
    Filed: October 28, 2004
    Date of Patent: May 10, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20050057853
    Abstract: A magnetic head having at least a main pole having a profile on a magnetic head air bearing surface composed of a first portion having a length in a cross-track direction which continuously increases from a leading edge to a trailing edge, and a second portion located on the side of the trailing edge of the first portion. A length of the second portion in the cross-track direction at the trailing edge is substantially equal to a length in the cross-track direction at the point of contact between the first and second portions. A rate of change in the length of the second portion in the cross-track direction from the leading edge to the trailing edge is different from a rate of increase in the length of the first portion in the cross-track direction.
    Type: Application
    Filed: October 28, 2004
    Publication date: March 17, 2005
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20040228030
    Abstract: A magnetic field distribution of a recording head is made linear so that a curvature of the magnetic-transition pattern in recording bit cells can be corrected. In a SPT head having a main pole 1 and an auxiliary pole 3, a magnetic layer 32 is disposed on a trailing side of the main pole. The magnetic layer is provided with a protruding portion 32a protruding towards the main pole. A width Nw of a side of the protruding portion opposite the main pole of the protruding portion is made smaller than a width Tww of the main pole on the trailing side.
    Type: Application
    Filed: October 28, 2003
    Publication date: November 18, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Masafumi Mochizuki, Atsushi Nakamura, Kimitoshi Etoh
  • Publication number: 20040218307
    Abstract: Arrangement of the flux enhanced part and the flux enhanced end of a main pole and the front or side surface of the main pole of a single-pole head for perpendicular recording is considered to prevent the influence of the leakage magnetic field from those parts and to enhance a field gradient in a portion for writing the boundary of a bit cell into a recording layer in a profile of a perpendicular magnetic field. A flux enhanced part 26 and a flux enhanced end 39 of a main pole are arranged on a leading side 25 rather than a vertical plane 36 in parallel with the cross track direction including the trailing edge of an air bearing surface of the main pole. Further, the front surface on the trailing side of the main pole is arranged on the leading side rather than the vertical plane.
    Type: Application
    Filed: June 8, 2004
    Publication date: November 4, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Atsuko Kuroda, Masafumi Mochizuki
  • Patent number: 6813116
    Abstract: A single-pole type magnetic head for perpendicular recording which reduces the amount of side writing even in the presence of a yaw angle and prevents the effective track width from decreasing, and a magnetic recording disk apparatus using the same. A main pole is composed of at least two portions where the width of the first portion continuously increases from the upstream side to the downstream side in the medium moving direction and the width of the second portion is the same as the width of the first portion's downstream edge in the medium moving direction and is constant from the upstream side to the downstream side in the medium moving direction. This prevents the recording magnetic field strength from decreasing at the track edge and increases the effective track width while suppressing side writing, thereby realizing a magnetic recording disk apparatus with a high track density.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: November 2, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20040184189
    Abstract: A magnetic head is composed to diminish disordered writing bits of a recording layer or reading noise caused by a magnetic field generated from an under layer without decreasing a writing magnetic field strength of the magnetic head. The magnetic head includes a write head provided with a main pole and one or more auxiliary poles, a read head provided with a read element, and coils located on both sides of the main pole in a manner to sandwich the main pole. The coil located on one side generates the asymmetrical magneto-motive force for magnetizing the main pole to that generated by the coil located on the other side.
    Type: Application
    Filed: January 30, 2004
    Publication date: September 23, 2004
    Inventors: Masafumi Mochizuki, Atsushi Nakamura, Yoji Maruyama
  • Publication number: 20040156142
    Abstract: When recording is performed on a perpendicular medium by using a single pole type head, there emerges a problem that the shape of magnetic transition is curved with respect to the track width direction due to the distribution of head write field. If the shape of magnetic transition is curved, there occur problems as follows: when reading is performed by a magnetoresistive head, the magnetic transition length appears to be large, so that the half-width of an isolated pulse is increased, and at the same time, the recording track width seems to be reduced with an increase in linear recording density. In the side on the trailing side of a main pole air bearing surface of a magnetic head for perpendicular recording, the central portion is situated closer to the leading side than the corners on the trailing side. In other words, the main pole air bearing surface is formed in the shape of a recess with respect to the tailing side.
    Type: Application
    Filed: February 10, 2004
    Publication date: August 12, 2004
    Applicant: HITACHI, LTD.
    Inventors: Masafumi Mochizuki, Tomohiro Okada, Atsushi Nakamura