Patents Assigned to Fujitsu
  • Radio receiving apparatus
    Patent number: 6175591
    Abstract: A radio receiving apparatus regenerates a clock synchronized to a symbol clock contained in a quadrature demodulated signal obtained by demodulating a multilevel quadrature modulated signal, converts the analog quadrature demodulated signal, at the timing at which the regenerated clock occurs, to digital data and outputs the digital data via a transversal equalizer. The apparatus includes a slope discriminator for outputting the slope of an in-phase signal constituting the quadrature demodulated signal. A FIR filter constructing the equalizer outputs, as an error signal between input and output signals of the equalizer, an output signal of the FIR filter which prevails when a center tap coefficient of the filter is regarded as being zero.
    Type: Grant
    Filed: February 12, 1998
    Date of Patent: January 16, 2001
    Assignee: Fujitsu Limited
    Inventor: Takanori Iwamatsu
  • Semiconductor device manufacturing method
    Patent number: 6174796
    Abstract: A semiconductor device manufacturing method having a copper wiring, comprises the steps of forming a second insulating film for covering the wiring on a first insulating film, forming a third insulating film which is made of material different from the second insulating film on the second insulating film, coating a resist on the third insulating film and then forming an opening over the wiring by exposing and developing the resist, forming a hole or groove in the third insulating film by etching the third insulating film via the opening, removing the resist by placing the semiconductor substrate in a plasma atmosphere containing oxygen in a chamber and simultaneously removing a part of the second insulating film via the hole or groove to expose the wiring via the hole or groove, and forming a metal film in the hole or groove.
    Type: Grant
    Filed: December 30, 1998
    Date of Patent: January 16, 2001
    Assignee: Fujitsu Limited
    Inventors: Hideo Takagi, Wataru Futo
  • Electrophotographic recording apparatus using developing device with one-component type developer and having combination of charge injection effect and conductive contact type charger
    Patent number: 6175710
    Abstract: An electrophotographic recording apparatus includes a photosensitive drum on which an electrostatic latent image can be written, a developing device for developing the latent image of a charged visible image with a one-component developer, and a transferring device for electrostatically transferring the charged visible image from the drum to a sheet or paper. The developing device has a conductive foam rubber roller for entraining the developer to form a developer layer therearound and for bringing the layer to the drum for the development of the latent image, a conductive blade resiliently engaged with the foam rubber roller for uniformly regulating a thickness of the developer, and an electric source for applying electric energy to the blade to electrically charge the developer layer by a charge-injection effect.
    Type: Grant
    Filed: January 6, 1994
    Date of Patent: January 16, 2001
    Assignee: Fujitsu Limited
    Inventors: Hideki Kamaji, Masae Ikeda, Kazunori Hirose, Hiroshi Nou, Masahiro Wanou, Teturou Nakashima, Masatoshi Kimura, Yukio Nishio
  • Packet relay control method packet relay device and program memory medium
    Patent number: 6175874
    Abstract: A control method and apparatus for distributing packets to nodes in a cluster, while realizing a single system image at the network address level and such as to be able to simply and dynamically change the distribution destination, conditions of distribution, and the like. A pattern matching unit in a relay device receives packets coming from a packet receiving device. The packets have an address which represents a cluster. Using a distribution control table, pattern matching is performed based on the transmission origin address, transmission origin port, destination port and the like of this packet. A hash calculation unit, from the matching result, performs a hash calculation obtaining the argument of a hash function. A destination node extraction unit sets the destination node of the packet based on the hash result, using the distribution control table.
    Type: Grant
    Filed: February 9, 1998
    Date of Patent: January 16, 2001
    Assignee: Fujitsu Limited
    Inventors: Yuji Imai, Mitsuhiro Kishimoto, Tsuneo Katsuyama
  • Electronic instrument and semiconductor memory device
    Patent number: 6172938
    Abstract: An electronic instrument includes a memory device, clock lines through which complementary clock signals are transmitted to be used for synchronization of a data output operation and a data input operation for the memory device, and strobe signal lines through which a first output strobe signal, a second output strobe signal, a first input strobe signal and a second input strobe signal are transmitted to be used to settle output data from the memory device in the data output operation and to settle input data supplied to the memory device, the first and second output strobe signals being in complementary relation to each other, the first and second input strobe signals being in complementary relation to each other.
    Type: Grant
    Filed: June 23, 1999
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Takaaki Suzuki, Masao Taguchi, Kotoku Sato
  • Optical module encapsulated with resin and manufacturing method therefor
    Patent number: 6170996
    Abstract: An optical module including a lead frame having a plurality of leads, a substrate mounted on the lead frame and having a plurality of conductive patterns, an optical element mounted on the substrate for making conversion between light and electricity, a sleeve placed on the substrate and having a front end adjacent to the optical element, and a first resin for encapsulating the optical element. The first resin has transparency to the light related to the optical element. The first resin is formed with a convex portion closing the front end of the sleeve. The conductive patterns of the substrate are connected through wires to the leads of the lead frame, respectively. The optical module further includes a molded second resin for enclosing all of the substrate, the optical element, the sleeve, the first resin, the wires, and the lead frame except a part of the sleeve and a part of each of the leads.
    Type: Grant
    Filed: June 8, 1999
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Kazunori Miura, Seimi Sasaki, Naoki Yamamoto
  • Heat sink and information processor using it
    Patent number: 6172872
    Abstract: The present invention relates to a heat sink. It is an object of the present invention to provide a heat sink at a low manufacturing cost, the life of the motor of which is long so that the reliability of the heat sink can be enhanced and, further, a sufficiently high cooling performance can be obtained and the designing of the heat sink can be easily performed. The heat sink includes: a bottom surface coming into contact with a heating element; a side on which a plurality of ventilation holes are formed; and an upper surface into which a cooling fan composed of blades and a motor is embedded and fixed.
    Type: Grant
    Filed: December 16, 1999
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventor: Tadashi Katsui
  • Disk unit creating a position sensitivity correction value using positive and negative cross points values of two-phase servo signals
    Patent number: 6172838
    Abstract: An actuator is provided with a step so as to allow FPC mounting surfaces of a read/write FPC band and of a relay FPC to be level with each other. Pointer information P4 in a ROM table is used to refer to a RAM table to acquire offset correction data. On-track control is effected at a cross point of two-phase servo signals N and Q. A value of this cross point is measured to find a position sensitivity correction value. A gap corresponding to encode loss is provided at the trailing position of each of sectors. In read operation, a sector pulse is generated with a delay corresponding to decode loss.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventor: Kazuhide Ohba
  • Method for correcting tilt of magnet-optical readable medium apparatus to be used for its practice and magnet-optical readable medium
    Patent number: 6172950
    Abstract: A tilt correction method carries out tilt correction by adjusting a magnet-optical readable medium. A tilt value is obtained by detecting crosstalk from a predetermined region of the magnet-optical readable medium, which is loaded with an apparatus to be used for practicing the tilt correction method. The tilt value is used to correct the tilt of the medium.
    Type: Grant
    Filed: December 17, 1997
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventor: Tsutomu Tanaka
  • Method for apparatus for producing a nozzle plate of an ink-jet head printer
    Patent number: 6170934
    Abstract: In a nozzle plate production method and apparatus, a metallic sheet material is punched to form nozzle holes therein by using a press having punches. Each of the punches includes a tapered conical portion, a straight cylindrical portion, and a rounded interconnecting portion. The interconnecting portion smoothly interconnects the conical portion and the cylindrical portion. Nibs produced on a bottom surface of the sheet material at the nozzle holes by the nozzle hole punching are removed by use of a tape grinding machine. A top surface and the bottom surface of the sheet material are buffed to provide a predetermined level of surface roughness. Burrs produced on the top and bottom surfaces of the sheet material at the nozzle holes by the buffing are removed by ultrasonic cleaning.
    Type: Grant
    Filed: September 26, 1997
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Takanobu Fujisawa, Yoshiaki Kawasaki, Tooru Tsukahara, Terukazu Kawarada, Masaharu Suzuki
  • Synchronization equipment
    Patent number: 6173023
    Abstract: The invention concerns synchronization equipment; more particularly, the invention is directed to the provision of synchronization equipment which, after simple hardware installation and software setting, establishes a synchronization network with an existing network, SDH elements, etc. that do not support SSMB.
    Type: Grant
    Filed: March 11, 1998
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Koji Tanonaka, Naoto Kidoku, Toshikazu Magome, Hiroyuki Suzuki
  • Magnetic recording medium containing fine magnetic crystal grains and its manufacture
    Patent number: 6171676
    Abstract: A magnetic recording medium has a substrate of a disk shape having a non-magnetic surface and a through hole formed at the central area of the substrate, and a plurality of dispersed island regions made of magnetic material and directly formed on the non-magnetic surface. The size of each of the island regions is a single magnetic domain size or finer of the magnetic material. The island regions are formed by cohering atoms of a magnetic film formed by sputtering.
    Type: Grant
    Filed: February 13, 1997
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Ryoichi Mukai, Kazunori Yamanaka, Kazuo Kobayashi
  • Disk control device adapted to reduce a number of access to disk devices and method thereof
    Patent number: 6173361
    Abstract: A disk control device is operationally connected to a high-order device and operates a plurality of disk devices. A cache is included in the disk control device for storing data including a plurality of parity data from a corresponding plurality of parity groups in the plurality of disk devices. The disk control device also includes a cache management table for indicating the positions of the data stored in the cache. Cache management means is provided for transferring a selected data request by the host control from the plurality of disk devices to the cache when the cache management table indicates that said selected data is not stored in the cache. Control means transfers the selected data from the cache to the high-order device when the cache management means informs the control means that the selected data is stored in the cache.
    Type: Grant
    Filed: May 22, 1998
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventor: Suijin Taketa
  • Non-volatile semiconductor memory device having a floating gate with protruding conductive side-wall portions
    Patent number: 6172394
    Abstract: A non-volatile semiconductor memory device includes memory cells each having a duplicate gate structure in which a floating gate and a control gate are stacked.
    Type: Grant
    Filed: April 30, 1999
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventor: Shinichi Nakagawa
  • System for monitoring execution of commands from a host for shared I/O devices by setting a time-out period based on control parameters sent by the host
    Patent number: 6173339
    Abstract: A command execution monitoring system includes a first unit which retains control parameters of an operation control command sent by one of host computers, the control parameters including an operation completion time. A second unit sequentially receives command entries sent for input/output devices by the host computers and retains the command entries in a table, each entry including a relative elapsed time measured from a time the entry is retained in the table. A third unit sets a time-out period of one of the host computers at the operation completion time retained by the first unit, so that execution of each of the entries in the table of the second unit is monitored based on a comparison between each of the relative elapsed times of the entries and the operation completion time.
    Type: Grant
    Filed: September 17, 1998
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventor: Keiichi Yorimitsu
  • Polishing method for planarizing a substrate
    Patent number: 6171514
    Abstract: A polishing method for planarizing a substrate which provides an efficient polishing so that a time needed for polishing is reduced as compared to the conventional method. A first polishing process removes a portion of a polish stop layer that covers a high area by using a first slurry having a high polishing capability against the polish stop layer. A second polishing process, subsequent to the first polishing process, removes the high area by using a second slurry having a high polishing capability for polishing a material covered by the polish stop layer. A polishing capability of the second slurry for polishing the polish stop layer is lower than the polishing capability of the first slurry for polishing the polish stop layer.
    Type: Grant
    Filed: March 3, 1998
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Kouichi Hara, Norikazu Ozaki
  • Carrying system and carrying method
    Patent number: 6170640
    Abstract: A carrying system for carrying a lead frame of a semiconductor device includes first and second carriers located on the same side of a carrier line, one carrier located above the other carrier. The first and second carriers are movable from along the carrier line, from a start point to a processing area and to an end point. The first and second carriers each include a holder for holding the lead frame on a specific end of the lead frame. By holding the lead frame on the same side of the carrier line and at a specific end of the lead frame, holding position deviation is minimized.
    Type: Grant
    Filed: January 27, 1998
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventor: Yukio Takayama
  • Storage medium driving device, storage medium and data protecting method
    Patent number: 6173390
    Abstract: A data protecting method wherein a resident control program which is stored as to be resident in a storage medium driving device judges on the basis of instruction from an executing device for executing a specified process, whether a control program for executing the process is incorporated or not therein, searches the control program from a set storage medium when the result of judgment is NO, reads in the searched control program, and incorporates the read-in control program therein. A storage medium driving device which stores this resident control program as to be resident, and a storage medium which is driven by this device.
    Type: Grant
    Filed: October 3, 1997
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Seigo Kotani, Naoya Torii, Jun Kamada
  • Recording disk apparatus
    Patent number: 6172842
    Abstract: A housing includes a base plate and a metallic cover. The cover may be formed by deep-drawing. The housing accommodates, for example, a magnetic disk, a magnetic head, and a drive mechanism. The drive mechanism serves to displace the magnetic head with respect to the magnetic disk. When the cover is coupled to the base plate, a screw is screwed, penetrating the cover, into the tip end of the carriage axis for supporting a carriage. Vibration caused by swinging movement of the carriage is transmitted to the cover through the screw. A vibration absorber adhered to the outer surface of the cover is adapted to absorb the transmitted vibration. Noise may be suppressed in the seek operation.
    Type: Grant
    Filed: July 8, 1998
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Ichi Satoh, Shoji Samma, Toshiyuki Hachiya, Takayuki Bitoh
  • Optical amplifier, optical amplifying apparatus, optical transmitter for use in optical communications system, and optical surge suppression method for the optical amplifier
    Patent number: 6172801
    Abstract: There is disclosed a technique regarding an optical amplifier in an optical communications system. In order to effectively suppress optical surges during amplification of signal light, through a simple structure, there is provided an amplifying medium which amplifies input light and outputs the amplified light, and reflecting members are connected to the input and output sides of the amplifying medium. The reflecting members can reflect light with a predetermined optical wavelength different from a signal light wavelength contained in the input light.
    Type: Grant
    Filed: September 9, 1997
    Date of Patent: January 9, 2001
    Assignee: Fujitsu Limited
    Inventors: Miki Takeda, Susumu Kinoshita