Patents Assigned to TDK Corporation
  • Publication number: 20040042118
    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 side erase occurs, more specifically 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: Application
    Filed: August 12, 2003
    Publication date: March 4, 2004
    Applicant: TDK Corporation
    Inventors: Yasuyuki Notsuke, Akihiro Oda, Tetsuya Roppongi
  • Publication number: 20040041683
    Abstract: In a first aspect of the present invention, a PTC composition contains (a) a crosslinked polymer matrix having a gel fraction of at least 10%, and (b) an electrically conductive substance. An article shaped therefrom yields an electric resistance of at least 50 m&OHgr; at 25° C. after being placed in an environment repeating 200 times of a temperature change between −40° C. and +85° C., and exhibits no thermal deformation when placed on a hot plate at 200° C. for 5 minutes.
    Type: Application
    Filed: May 27, 2003
    Publication date: March 4, 2004
    Applicant: TDK Corporation
    Inventors: Hisanao Tosaka, Yasuhide Yamashita, Tokuhiko Handa, Katsumi Kobayashi
  • Publication number: 20040042132
    Abstract: Provided are a magnetic transducer capable of increasing a resistance change and obtaining an appropriate coercive force, a thin film magnetic head, a method of manufacturing a magnetic transducer and a method of manufacturing a thin film magnetic head.
    Type: Application
    Filed: August 22, 2003
    Publication date: March 4, 2004
    Applicant: TDK CORPORATION
    Inventors: Yoshihiro Tsuchiya, Satoru Araki, Masashi Sano
  • Publication number: 20040043255
    Abstract: An optical recording medium has at least a substrate, and a recording layer arranged on the substrate. The recording layer contains at least a first dye (main component) which has a maximum absorption wavelength in a range of 450 to 600 nm, and a second dye which has a maximum absorption wavelength in a range of 600 to 750 nm. A content of the second dye in the recording layer is adjusted so that an attenuation coefficient &agr; of the recording layer with respect to a light of a wavelength 655 nm, and an attenuation coefficient &bgr; of the recording layer with respect to a light of a wavelength 670 nm can simultaneously satisfy conditions represented by the following equations (1) to (3): (1) 0.03≦&agr;, (2) 0.03≦&bgr;, (3) 0.7≦(&agr;/&bgr;)≦1.05.
    Type: Application
    Filed: August 14, 2003
    Publication date: March 4, 2004
    Applicant: TDK CORPORATION
    Inventors: Takashi Horai, Syuji Tsukamoto, Narutoshi Fukuzawa, Hiroyuki Arioka
  • Patent number: 6700368
    Abstract: A method of analyzing characteristics of a magnetic transducer includes sub-dividing a region to be analyzed in a magnetic transducer into a plurality of polyhedral elements, and performing a transient calculation. The transient calculation includes calculating a transient electric field of each polyhedral element, calculating a transient magnetic field of each polyhedral element, and updating the magnetic permeability in accordance with a magnetic flux density determined from the calculated transient magnetic field. The steps of performing transient calculation are repeated until a predetermined number of time steps have been completed, in order to determine electric fields and magnetic fields of all of the plurality of polyhedral elements in the region to be analyzed.
    Type: Grant
    Filed: July 11, 2002
    Date of Patent: March 2, 2004
    Assignee: TDK Corporation
    Inventor: Ken-ichi Takano
  • Patent number: 6699557
    Abstract: An optical recording medium (10) is adapted such that information is recorded by forming recording marks on a recording layer (12) that covers grooves (16) of an optical transparent substrate (14). In the recording layer (16), contiguously defined along a feed direction S of irradiation are virtual recording cells (40) which have a given unit length in the feed direction S of irradiation along the groove 16 and a given unit width in the direction orthogonal thereto. In addition, the groove width W is set so that 0.20×(&lgr;/NA)<W<0.50×(&lgr;/NA), where &lgr; is the wavelength of a laser beam to be irradiated with and NA is the numerical aperture of the objective lens for the laser beam in a irradiation optical system. The irradiation time is set in five stages or more to radiate the laser beam, thereby making it possible to record information in multi-levels.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: March 2, 2004
    Assignee: TDK Corporation
    Inventors: Hiroyuki Arioka, Syuji Tsukamoto, Takashi Horai, Shirou Ootsuki
  • Patent number: 6700749
    Abstract: A precise positioning actuator to be fixed to a head slider provided with at least one head element and to a support, for precisely positioning the at least one head element, includes a pair of movable arms formed by a metal plate. These movable arms are capable of displacing in response to a drive signal applied to the actuator along a direction crossing a plate plane of the movable arms, and catch the head slider in a space between them.
    Type: Grant
    Filed: October 10, 2001
    Date of Patent: March 2, 2004
    Assignee: TDK Corporation
    Inventors: Masashi Shiraishi, Tamon Kasajima
  • Patent number: 6698084
    Abstract: A method for manufacturing radio frequency module components with a surface acoustic wave element includes a gold plating step of plating gold at a component bonded portion on a conductive surface of a ceramic multi-layer substrate 40 to have a mounted electrode 43, a surface acoustic wave element mounting step of face down bonding a flip chip 30 as the surface acoustic wave element on the ceramic multi-layer substrate 40 by the gold—gold connection, a side wall formation step of bonding a side wall member 60 surrounding the flip chip 30 onto the ceramic multi-layer substrate 40 by adhesives, a lid formation step of bonding a lid member 61 enclosing an opening of the side wall onto the side wall member by adhesives, after mounting the flip chip 30, and a soldered component mounting step of mounting a soldered component 50 by the use of solder, after the lid formation step.
    Type: Grant
    Filed: September 7, 2001
    Date of Patent: March 2, 2004
    Assignee: TDK Corporation
    Inventor: Fumio Uchikoba
  • Patent number: 6699809
    Abstract: A dielectric ceramic composition including a dielectric base phase containing BaTiO3 as a main component, and plate-shaped or acicula deposition phase existing together in the dielectric base phase. Preferably, the dielectric ceramic composition includes a main component of BaTiO3, a first subcomponent including at least one compound selected from MgO, CaG, BaG, SrO and Cr2O3, a second subcomponent of (Ba, Ca)xSiO2+x (where, x=0.8 to 1.2), a third subcomponent including at least one compound selected from V2O5, MoO3, and WO3, and a fourth subcomponent including an oxide of R1 (where R1 is at least one element selected from Sc, Er, Tm, Yb, and Lu), a fifth subcomponent including an oxide of R2 (where R2 is at least one element selected from Y, Dy, Ho, Tb, Gb and Eu), wherein the ratios of the subcomponents to 100 moles of the main component of BaTiO3 are first subcomponent of 0.1 to 3 moles, second subcomponent of 2 to 10 moles, third subcomponent of 0.01 to 0.5 mole, fourth subcomponent of 0.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: March 2, 2004
    Assignee: TDK Corporation
    Inventors: Yoshinori Fujikawa, Yoshihiro Terada, Shigeki Sato
  • Patent number: 6700740
    Abstract: A top pole layer has a first portion and a second portion. The first portion has an end located in an air bearing surface, has a constant width equal to a write track width, and includes a pole portion. The second portion is coupled to the other end of the first portion and includes a yoke portion. The first portion, a write gap layer, and a part of the bottom pole layer closer to the write gap layer have an equal width in a region where the first portion of the top pole layer and the bottom pole layer are opposed to each other via the write gap layer. The thickness of the first portion of the top pole layer in a region extending from the air bearing surface to a predetermined position is smaller than the thickness of the other part of the top pole layer adjacent to this region.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: March 2, 2004
    Assignees: TDK Corporation, SAE Magnetics (H.K.) Ltd.
    Inventors: Naoto Matono, Tetsuya Kuwashima
  • Patent number: 6700300
    Abstract: A compact and wide band surface acoustic wave device for intermediate-frequency is disclosed. A piezoelectric substrate for use in a surface acoustic wave device having high electromechanical coupling factor and low SAW velocity is also disclosed. The surface acoustic wave device is constituted of a piezoelectric substrate 1 and inter-digital electrodes 2, 2 formed on the piezoelectric substrate 1. The piezoelectric substrate 1 has a crystal structure of Ca3Ga2Ge4O14 and is represented by the chemical formula, Ca3TaGa3Si2O14. A cut angle of the piezoelectric substrate 1 cut out of the single crystal and a direction of propagation of surface acoustic waves on the piezoelectric substrate represented in terms of Euler's angles (&phgr;, &thgr;, &psgr;) are found in an area represented by −2.5°≦&phgr;≦2.5°, 30°≦&thgr;≦90°, and −65°≦&psgr;≦65°.
    Type: Grant
    Filed: October 2, 2001
    Date of Patent: March 2, 2004
    Assignee: TDK Corporation
    Inventors: Kenji Inoue, Katsuo Sato, Hiroki Morikoshi, Katsumi Kawasaki, Jun Sato
  • Publication number: 20040038800
    Abstract: A dielectric ceramic composition, comprising a main component including barium titanate, a fourth subcomponent including an oxide of R1 (note that R1 is at least one kind selected from a first element group composed of rare-earth elements having a effective ionic radius of less than 108 pm when having a coordination number of nine), and a fifth subcomponent including an oxide of R2 (note that R2 is at least one kind selected from a second element group composed of rare-earth elements having a effective ionic radius of 108 pm to 113 pm when having a coordination number of nine). According to the composition, a dielectric ceramic composition having excellent reducing resisting property at firing, excellent temperature dependence of capacitance after firing, and improved accelerated lifetime of insulation resistance can be provided.
    Type: Application
    Filed: January 15, 2003
    Publication date: February 26, 2004
    Applicant: TDK Corporation
    Inventors: Yuusaku Horie, Yukie Nakano, Kaori Masumiya
  • Publication number: 20040035493
    Abstract: A clean box is composed of a box body having an opening in one surface thereof and a lid member for closing the opening. An annular groove is formed so as to surround the opening on one of the box body or the lid member for defining a suction space sealed between the lid member and the box body under the condition that the lid member is mounted on the box body. Furthermore, intake/exhaust ports are provided for vacuum exhaust/release from the outside.
    Type: Application
    Filed: June 23, 2003
    Publication date: February 26, 2004
    Applicant: TDK CORPORATION
    Inventors: Toshihiko Miyajima, Tsutomu Okabe
  • Publication number: 20040038080
    Abstract: An optical recording medium includes a substrate, two recording layers provided on the substrate and two dielectric layers each provided adjacent to one of the recording layers, the optical recording medium being constituted so that when it is irradiated with a laser beam having a wavelength &lgr; via an objective lens having a numerical aperture NA satisfying &lgr;/NA≦640 nm from the side opposite from the substrate, a record mark whose reflection coefficient is different from those of other regions of the recording layers is formed in the recording layers and at least a part of a region(s) of the dielectric layers adjacent to the record mark is crystallized to form a crystallized region. According to the thus constituted optical recording medium, it is possible to reproduce a signal having excellent signal characteristics.
    Type: Application
    Filed: June 27, 2003
    Publication date: February 26, 2004
    Applicant: TDK Corporation
    Inventors: Hiroyasu Inoue, Koji Mishima, Masaki Aoshima
  • Publication number: 20040037015
    Abstract: Provided is a magnetic reproducing apparatus capable of controlling a magnetic domain of a free layer, and obtaining a sufficient reproduction output even if the size of an MR device is reduced. The MR device is formed so as to have a laminate structure in which a semi-hard magnetic layer and a first ferromagnetic layer (free layer) are exchange-coupled to each other through a non-magnetic exchange coupling layer. Unlike an abutted junction structure using a hard magnetic layer, the distribution of a magnetic bias applied from the semi-hard magnetic layer to the first ferromagnetic layer becomes uniform, thereby the first ferromagnetic layer is brought into a single magnetic domain state. Moreover, the semi-hard magnetic layer has a moderate coercive force lying halfway between soft magnetism and hard magnetism, so the magnetization direction of the first ferromagnetic layer is not fixed.
    Type: Application
    Filed: July 23, 2003
    Publication date: February 26, 2004
    Applicant: TDK Corporation
    Inventors: Takashi Asatani, Fujimi Kimura
  • Patent number: 6696907
    Abstract: A deflecting yoke core with which magnetic saturation is prevented by optimizing the relationship between the core sectional area and the density of the magnetic flux distribution. The deflecting yoke core to be mounted between a neck and a funnel of a cathode ray tube has a hole 2 extending from an opening end of a neck portion 3 to an opening end of a funnel portion 1. The hole 2 at the funnel portion 1 widens toward the opening end of the funnel portion 1. An outer shape at the opening end of the funnel portion 1 has a short diameter Dx1 along a minor axis X and a long diameter Dy1 along a major axis Y. Core sectional areas along a plane parallel to and passing through a core axis O1 are largest within an angular range of 30° to 65° measured around the core axis O1 from a 0° reference angle at the minor axis X.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: February 24, 2004
    Assignee: TDK Corporation
    Inventors: Hitoshi Iwaya, Shinichiro Ito, Minoru Anbo, Masahiro Ono
  • Patent number: 6697220
    Abstract: The invention provides a thin film magnetic head having a minute magnetic pole width and an excellent overwriting characteristic and a method of manufacturing thereof. A top magnetic layer includes a first magnetic pole tip and a second magnetic pole tip in order from a side further from the gap layer. A thin film coil is located in a rearward area specified by thickness of the first magnetic pole tip of the top magnetic layer. A thickness of the thin film coil can be determined suitably, and a required and sufficient quantity of a magnetic flux can be generated by energizing the thin film coil.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: February 24, 2004
    Assignee: TDK Corporation
    Inventor: Yoshitaka Sasaki
  • Patent number: 6696736
    Abstract: The surface acoustic wave device comprises a piezoelectric substrate (1) and a pair of interdigitated electrodes (2) provided on one main surface of the piezoelectric substrate (1). As the material of the piezoelectric substrate (1), a single crystal belonging to the point group 32, having a crystal structure of Ca3Ga2Ge4O14 type, containing Ca, Nb, Ga, Si and O as main components, and being represented by the chemical formula Ca3NbGa3Si2O14 is used. The cut angle of the substrate (1) and the propagation direction can be selected as appropriate to thereby realize the substrate (1) which has a large electromechanical coupling coefficient that is effective to achieve a wider passband and a low SAW velocity that is effective to reduce the size of a surface acoustic wave device.
    Type: Grant
    Filed: January 14, 2003
    Date of Patent: February 24, 2004
    Assignee: TDK Corporation
    Inventors: Kenji Inoue, Katsuo Sato, Hiroki Morikoshi, Jun Sato
  • Publication number: 20040033363
    Abstract: The present invention aims at realizing a phosphor thin film having a high luminance with a low emission threshold voltage, and an EL element comprising the same. The EL element of the present invention comprises a substrate, and a lower electrode, a lower buffer thin film containing a sulfide such as ZnS, a phosphor thin film containing an oxide such as a gallate as a matrix material, an upper buffer thin film containing a sulfide such as ZnS, and an upper electrode which are successively laminated on the substrate.
    Type: Application
    Filed: March 24, 2003
    Publication date: February 19, 2004
    Applicant: TDK Corporation
    Inventors: Yoshihiko Yano, Masaki Takahashi, Tomoyuki Oike, Naruki Kataoka
  • Publication number: 20040032812
    Abstract: An optical recording/reproducing method and an optical recording medium capable of performing excellent optical recording with a simple structure in a recording layer made of environmentally friendly materials. The optical recording medium has a recording layer on a substrate. The recording layer has a pair of dielectric layers of which states are altered by a laser beam that is an energy beam of which intensity is modulated according to information to be recorded. This recording layer also has a state-change assisting layer sandwiched by these dielectric layers. The state-change assisting layer includes an element selected from Sn, Ti, Si, Bi, Ge, and C as a principle component, while the dielectric material as a base material for the dielectric layers is at least one of ZnS, SiO2, AlN, and Ta2O5.
    Type: Application
    Filed: May 29, 2003
    Publication date: February 19, 2004
    Applicant: TDK CORPORATION
    Inventors: Hiroyasu Inoue, Koji Mishima, Kazuki Suzawa