Patents by Inventor Tetsuya Roppongi

Tetsuya Roppongi 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: 7522376
    Abstract: Provided is a thin film magnetic head capable of appropriately control the flow of magnetic flux from a yoke layer to a pole layer so as to prevent information from being overwritten without intention during recording. A perpendicular recording system thin film magnetic head is formed so that a portion of a yoke layer and a portion of a pole layer are connected to each other in a connecting surface. When a large amount of the magnetic flux contained in the yoke layer flows into the pole layer through the connecting surface, the large amount of the magnetic flux is concentrated in the connecting surface, so an excessive amount of the magnetic flux is not supplied to a front end portion of the pole layer, and an appropriate amount of the magnetic flux is supplied.
    Type: Grant
    Filed: November 4, 2003
    Date of Patent: April 21, 2009
    Assignee: TDK Corporation
    Inventors: Naoto Matono, Tetsuya Roppongi, Norikazu Ota
  • Patent number: 7508626
    Abstract: The present invention provides a thin film magnetic head in which a magnetic domain structure of a magnetic pole layer is controlled and fluctuation in recording magnetization caused by leaked magnetic flux generated by unintentional shift of a magnetic domain wall can be prevented. When a length of a front end portion of a magnetic pole part layer, which specifies a recording track width of a recording medium, is set as D, and a width of an upper edge of a magnetic pole end surface, positioned on a medium outflow side, is set as W, a dimensional ratio D/W of the length D to the width W is set so as to lie within the range of 0<D/W?2.3. Since magnetic domain stability of the magnetic pole part layer is assured on the basis of the proper formation of the shape of the front end portion, leak of magnetic flux from the front end portion immediately after recording is suppressed. Therefore, occurrence of an inconvenience such as unintended erasure of information caused by the leaked magnetic flux is prevented.
    Type: Grant
    Filed: November 25, 2003
    Date of Patent: March 24, 2009
    Assignees: TDK Corporation, SAE Magnetics (H.K.) Ltd.
    Inventors: Shigeru Ichihara, Akihiro Oda, Tetsuya Roppongi, Naoto Matono
  • Patent number: 7463449
    Abstract: A pole layer incorporate a track width defining and a wide portion. A material forming the pole layer is an alloy whose major elements are iron and nickel. In the alloy, where the proportions of iron and nickel with respect to the total of iron and nickel are indicated as (100?M) weight % and M weight %, respectively, M is greater than 0 and smaller than or equal to 10. The internal stress of the pole layer is a tensile stress. The magnetostriction constant of the material forming the pole layer is positive. Where the anisotropy field of the pole layer is Hk (A/m), the magnetostriction constant of the material forming the pole layer is ?(×10?6), and the internal stress of the pole layer is ? (MPa), the value of Hk/(?×?) is greater than 0.01 and smaller than 0.2.
    Type: Grant
    Filed: November 4, 2005
    Date of Patent: December 9, 2008
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Atsushi Yamaguchi, Tetsuya Roppongi, Kiyoshi Noguchi
  • Publication number: 20080291582
    Abstract: Provided is a thin film magnetic head capable of suppressing an occurrence of a track erase, decreasing an influence on a magnetoresistive element caused by a magnetic flux generated from a thin film coil, and further decreasing the parasitic capacity. The thin film magnetic head has, in order in a stacked direction, a first magnetic shield layer, a magnetoresistive element, a second magnetic shield layer, a third magnetic shield layer, a main magnetic pole layer and a return yoke layer. A width in a track width direction of at least one of the first and the second magnetic shield layers is smaller than widths in a track width direction of the third magnetic shield layer and the return yoke layer.
    Type: Application
    Filed: May 21, 2007
    Publication date: November 27, 2008
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Norikazu Ota, Yuichi Watabe, Tetsuro Sasaki, Takeo Kagami, Tetsuya Roppongi, Kazuki Sato, Yuji Otsubo, Sohei Horiuchi, Yoshiaki Tanaka, Kenji Yokoyama, Noriaki Kasahara
  • Patent number: 7443633
    Abstract: A thin-film magnetic head with which an error rate is decreased due to a reduction of a jitter without significant decrease in write field, is provided. The head comprises at least one inductive write head element comprising: a main magnetic pole layer having an inner saturation magnetic flux density varying from both side end surfaces in a track-width direction and a leading end surface, toward a center portion in the track-width direction of a trailing end surface; an auxiliary magnetic pole layer; and at least one coil layer, a curvature width WC of a contour line of a write field adjacent to a trailing edge on an ABS side of the main magnetic pole layer satisfying the following expression: ?0.15*WT?WC<12 where WT is a track width and a unit of WC and WT is nanometer.
    Type: Grant
    Filed: December 15, 2005
    Date of Patent: October 28, 2008
    Assignees: TDK Corporation, SAE Magnetics (H.K.) Ltd.
    Inventors: Katsumichi Tagami, Tatsuya Harada, Hiroki Matsukuma, Tetsuya Roppongi, Susumu Aoki, Kazumasa Fukuda, Naoto Matono
  • Publication number: 20080180858
    Abstract: Provided are a perpendicular magnetic write head capable of achieving the high performance and stability in the writing performance, and a method of manufacturing the same. On a trailing side of a main magnetic pole layer, disposed are a gap layer extending backward from an air bearing surface and an auxiliary magnetic pole layer extending backward from a position recessed from the air bearing surface. The auxiliary magnetic pole layer is partially overlapped on the gap layer. In case the auxiliary magnetic pole layer is formed using etching method in the process of manufacturing the perpendicular magnetic write head, the gap layer has a function as an etching stopper layer so that the main magnetic pole layer is protected; thereby the already-formed main magnetic pole layer is not subjected to etching.
    Type: Application
    Filed: January 22, 2008
    Publication date: July 31, 2008
    Applicant: TDK CORPORATION
    Inventors: Norikazu Ota, Tetsuya Roppongi, Yuichi Watabe
  • Publication number: 20080151436
    Abstract: Provided is a thin-film magnetic head capable of writing data with high accuracy on a magnetic recording medium having high coercive force without heating. The head comprises an electromagnetic coil element comprising: a main magnetic pole; an auxiliary magnetic pole; and a write coil formed so as to pass through at least between the main magnetic pole and the auxiliary magnetic pole, for generating the write magnetic field. In this head, a part of the write coil has a layered structure of: a resonance coil layer for generating a resonance magnetic field having ferromagnetic resonance frequency of a magnetic recording layer of a magnetic recording medium or having a frequency in the vicinity thereof; and a write coil layer. And further, the resonance coil layer and the write coil layer sandwich an insulating layer therebetween.
    Type: Application
    Filed: October 9, 2007
    Publication date: June 26, 2008
    Applicant: TDK CORPORATION
    Inventors: Isamu Sato, Tetsuya Roppongi, Yuichi Watabe, Norikazu Ota, Hiroshi Ikeda, Mikio Matsuzaki
  • Patent number: 7379268
    Abstract: A thin-film magnetic head comprises first and second magnetic layers, a gap layer provided between the first and second magnetic layers, a coupling portion for magnetically coupling the first and second magnetic layers to each other at a distance from a medium facing surface ABS, and a thin-film coil, part of which is disposed between the first and second magnetic layers. The second magnetic layer has a pole portion layer and a yoke portion layer. The thin-film magnetic head further comprises a non-magnetic layer that is in contact with the surface of the pole portion layer farther from the gap layer. The non-magnetic layer prevents the surface of the pole portion layer farther from the gap layer from being damaged during the manufacturing process of the head, and thereby maintains the flatness of the surface.
    Type: Grant
    Filed: November 5, 2001
    Date of Patent: May 27, 2008
    Assignee: TDK Corporation
    Inventors: Yoshikazu Sato, Tetsuya Roppongi, Yuichi Watabe
  • Publication number: 20080094755
    Abstract: The present invention provides a thin-film magnetic head which surely improves the writing and reading characteristic with reducing the flying height and surely handles the contact or collision with the magnetic recording medium. A thin-film magnetic head is provided, which includes, an substrate with ABS; a read or write head element provided on an element-formed surface of the substrate; at least one protrusion adjustment portion whose end reaches a slider end surface on the ABS side, which provides on an element-formed surface of the substrate; at least one heating portion provided rear at least one protrusion adjustment portion viewed from the slider end surface on the ABS side.
    Type: Application
    Filed: October 17, 2007
    Publication date: April 24, 2008
    Applicant: TDK CORPORATION
    Inventors: Norikazu OTA, Tetsuya ROPPONGI, Hiraku HIRABAYASHI, Yuichi WATABE
  • Patent number: 7359146
    Abstract: The soft magnetic film takes its hard axis along the direction in which a magnetic field is generated and its easy axis along a direction perpendicular to the direction of the writer magnetic field. The magnetic bias film applies a magnetic bias along the easy axis to the soft magnetic film.
    Type: Grant
    Filed: July 15, 2004
    Date of Patent: April 15, 2008
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Kiyoshi Noguchi, Tetsuya Mino, Tetsuya Roppongi
  • Patent number: 7312951
    Abstract: The invention provides a magnetic head for perpendicular magnetic recording having an air bearing surface positioned facing the recording surface of a recording medium, which records magnetic information on the recording medium by generating magnetic flux toward the recording surface of the recording medium, and comprises a magnetic pole which generates magnetic flux toward the recording surface of the recording medium and a return yoke having one end connected to the magnetic pole and the other end positioned facing the recording surface of the recording medium, wherein the material composing the magnetic pole has a magnetostriction constant ? of at least 0 and less than 10×10?6, with a parameter P represented by the formula: P=Hk/(?×?) (where Hk represents the magnetic anisotropic field (A/m), ? represents the stress (MPa) and ? represents the magnetostriction constant) of larger than 0.1 and less than 200.
    Type: Grant
    Filed: January 21, 2005
    Date of Patent: December 25, 2007
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Kiyoshi Noguchi, Tetsuya Roppongi, Atsushi Yamaguchi
  • Publication number: 20070279803
    Abstract: The invention provides a thin-film magnetic head wherein the combined release angle ? for a dominant recording magnetic field generated from a magnetic pole layer toward a patterned media for the purpose of recording magnetic information is set to within an angle range of 35° to 65° with respect to a patterned media surface. It is thus possible to invert, with efficiency and reliability, the directions of magnetization of isolate bits lined up on the patterned media for high-density recording.
    Type: Application
    Filed: May 31, 2007
    Publication date: December 6, 2007
    Applicant: TDK Corporation
    Inventors: Kei Hirata, Tetsuya Roppongi, Kiyoshi Noguchi
  • Publication number: 20070274003
    Abstract: The invention provides a magnetic recording/reproducing system constructed such that until the skew angle is past the maximum skew angle ?max, the edges of the write shield layer and the edges of the lower read shield layer do not overlap on the same track, so that upon application of an external magnetic field, the already written signals are kept back from degradation.
    Type: Application
    Filed: May 17, 2007
    Publication date: November 29, 2007
    Applicant: TDK Corporation
    Inventors: Norikazu OTA, Tetsuya ROPPONGI
  • Publication number: 20070253106
    Abstract: A magnetic head apparatus is provided which is capable of recording data in a recoding layer having high coercive force with high accuracy without heating. A magnetic recording and reproducing apparatus is also provided which has the magnetic head apparatus. A recording head has: a main magnetic pole; a recording-side front-end shield (a return magnetic pole); a recording-side rear-end shield (a return magnetic pole); a main coil for generating a perpendicular recording magnetic field at the main magnetic pole; and an auxiliary coil for generating a longitudinal alternating current magnetic field having a frequency in the microwave band at the main magnetic pole.
    Type: Application
    Filed: April 26, 2007
    Publication date: November 1, 2007
    Applicant: TDK CORPORATION
    Inventors: Isamu Sato, Yoshikazu Soeno, Koichi Terunuma, Tetsuya Roppongi, Hiroshi Ikeda
  • Patent number: 7245454
    Abstract: A write head of a magnetic head for vertical magnetic recording comprises: a coil; a main pole layer that allows the magnetic flux corresponding to the magnetic field generated by the coil to pass therethrough and generates a write magnetic field; an auxiliary pole layer; a gap layer provided between the main pole layer and the auxiliary pole layer; and a yoke layer for magnetically coupling the main pole layer to the auxiliary pole layer. The main pole layer has a flat top surface. In the main pole layer the position in which the thickness starts to increase is located between the medium facing surface and the position in which the width starts to increase.
    Type: Grant
    Filed: April 27, 2004
    Date of Patent: July 17, 2007
    Assignee: TDK Corporation
    Inventors: Susumu Aoki, Yasuyuki Notsuke, Yuichi Watabe, Norikazu Ota, Tetsuya Roppongi
  • Patent number: 7219414
    Abstract: A main pole layer of a magnetic head includes a first portion disposed at a distance from a medium facing surface, and a second portion that is smaller in thickness than the first portion and disposed between the first portion and the medium facing surface. The step of forming the main pole layer includes the steps of forming a plating layer such that one of ends of the plating layer closer to the medium facing surface is located at a position that coincides with the position of one of ends of the first portion closer to the medium facing surface; forming a first nonmagnetic layer to cover the plating layer; polishing the first nonmagnetic layer and the plating layer; forming a space by removing the plating layer; forming a magnetic layer, which will be the main pole layer, in the space and on the top surface of the first nonmagnetic layer; forming a second nonmagnetic layer to cover the magnetic layer; and polishing the second nonmagnetic layer and the magnetic layer.
    Type: Grant
    Filed: January 25, 2005
    Date of Patent: May 22, 2007
    Assignee: TDK Corporation
    Inventors: Yuichi Watabe, Susumu Aoki, Yasuyuki Notsuke, Tetsuya Roppongi
  • Patent number: 7206166
    Abstract: Provided is a thin film magnetic head which enables both ensuring overwrite characteristics and preventing an adverse effect resulting from side erase, such as degradation in an output signal. An exposed surface of a magnetic pole portion layer is configured to have the shape of an asymmetric inverted trapezoid corresponding to a remaining region which remains after removing a width increasing region in the shape of a right triangle from a rectangular region on the side of a side edge. The side edge of the exposed surface is caused to correspond to the side on which a magnetic flux emitted from the magnetic pole portion layer onto a target track of a hard disk causes information to unintentionally overwrite existing information recorded on an adjacent track. This configuration allows preventing the exposed surface from extending to the adjacent track, thus preventing the adverse effect resulting from side erase.
    Type: Grant
    Filed: August 12, 2003
    Date of Patent: April 17, 2007
    Assignee: TDK Corporation
    Inventors: Yasuyuki Notsuke, Akihiro Oda, Tetsuya Roppongi
  • Patent number: 7154707
    Abstract: Provided is a thin film magnetic head capable of securing recording characteristics even in the case where a return pole layer is disposed on a medium-outgoing side of the pole layer. The return yoke layer is disposed on a trailing side of the pole layer, and a neck height NH is within a range of NH?W1 (a width of a front end portion in a main pole layer)+0.05 ?m, and a height ratio (a ratio of the neck height NH to a throat height TH) NH/TH is within a range of 0.5<NH/TH<1.6. Thereby, the neck height NH and the height ratio NH/TH which have an influence on the recording characteristics can become appropriate, so even if the thickness of the gap layer is 0.2 ?m or less to bring the return yoke layer closer to the pole layer, overwrite characteristics can be secured.
    Type: Grant
    Filed: March 22, 2004
    Date of Patent: December 26, 2006
    Assignees: TDK Corporation, SAE Magnetics (H.K) Ltd.
    Inventors: Yuichi Watabe, Norikazu Ota, Yasuyuki Notsuke, Susumu Aoki, Tetsuya Roppongi, Naoto Matono
  • Publication number: 20060158779
    Abstract: A magnetic head for perpendicular magnetic recording comprises: a pole layer, a write shield layer, and a gap layer provided between the pole layer and the write shield layer. The pole layer incorporates a track width defining portion and a wide portion. The track width defining portion has an end located in a medium facing surface and defines the track width. The wide portion is coupled to the other end of the track width defining portion and has a width greater than the width of the track width defining portion. The value of NH×TH/WG is greater than zero and smaller than or equal to 0.85 ?m, where NH is the distance from the medium facing surface to the boundary between the track width defining portion and the wide portion, WG is the space between the pole layer and the write shield layer taken in the medium facing surface, and TH is the distance from the medium facing surface to a point at which the space between the pole layer and the write shield layer starts to be greater than WG.
    Type: Application
    Filed: December 16, 2005
    Publication date: July 20, 2006
    Applicant: TDK Corporation
    Inventors: Norikazu Ota, Tetsuya Roppongi
  • Publication number: 20060132972
    Abstract: A thin-film magnetic head with which an error rate is decreased due to a reduction of a jitter without significant decrease in write field, is provided. The head comprises at least one inductive write head element comprising: a main magnetic pole layer having an inner saturation magnetic flux density varying from both side end surfaces in a track-width direction and a leading end surface, toward a center portion in the track-width direction of a trailing end surface; an auxiliary magnetic pole layer; and at least one coil layer, a curvature width WC of a contour line of a write field adjacent to a trailing edge on an ABS side of the main magnetic pole layer satisfying the following expression: ?0.15*WT=WC<12 where WT is a track width and a unit of WC and WT is nanometer.
    Type: Application
    Filed: December 15, 2005
    Publication date: June 22, 2006
    Applicants: TDK Corporation, SAE Magnetics (H.K) Ltd., SAE Technology Centre.
    Inventors: Katsumichi Tagami, Tatsuya Harada, Hiroki Matsukuma, Tetsuya Roppongi, Susumu Aoki, Kazumasa Fukuda, Naoto Matono