Patents by Inventor Takehiro Ohkawa

Takehiro Ohkawa 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: 7212124
    Abstract: Provided is a portable information device having an RFID, the device being a device in which no effect is produced on original communication of the portable information device for which an EMC measure is taken, the device having good productivity, and the device keeping communication distance without damaging portability. A place where an antenna is set is located on the side of a battery cover of a battery receiving section to make the communication distance of an incorporated RFID long. A circuit configuration wherein a condenser for resonance is connected to both ends of the antenna coil and an IC is connected to an intermediate tap of the antenna coil is made so as to make it unnecessary that the resonance frequency of the RFID is individually adjusted and make the production of the RFID easy.
    Type: Grant
    Filed: June 26, 2003
    Date of Patent: May 1, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Takehiro Ohkawa, Hiroshi Yoshigi
  • Patent number: 6972662
    Abstract: An RFID which provides a wide working voltage range and general versatility at low cost, without the need for changing its internal circuit design due to external factors. In the RFID, there is provided an arrangement that a low impedance state is given when its internal data communication circuit is in a reset state.
    Type: Grant
    Filed: August 15, 2000
    Date of Patent: December 6, 2005
    Assignee: Renesas Technology Corp.
    Inventors: Takehiro Ohkawa, Miki Yuyama, Hiroshi Yoshigi, Tadashi Oonishi, Kazuki Watanabe
  • Publication number: 20050122211
    Abstract: In an RFID (contactless identification) having a resonant circuit, the resonant frequency is directly affected by variations in the input capacitance of an IC chip due to certain manufacturing factors, causing a direct influence on a power reception efficiency and a communication distance. Thus, an RFID is provided for eliminating a step of correcting such variations, reducing the manufacturing cost, and efficiently receiving the power. An IC chip is connected to an intermediate tap of an antenna coil in series through a capacitor. Alternatively, the capacitor is replaced with two capacitors, through one of which the IC chip is connected to the intermediate tap of the antenna coil.
    Type: Application
    Filed: February 9, 2004
    Publication date: June 9, 2005
    Inventors: Hiroshi Yoshigi, Takehiro Ohkawa
  • Publication number: 20040233043
    Abstract: A communication system is provided which enhances communication stability, using chips on which function blocks are formed including sensor, chip ID, and radio transmission/reception functions. The sensor detects biological and chemical materials and physical and stoichiometric quantities such as temperature, pressure, and pH and the sensed results are transmitted to a reader by a radio frequency (RF) function. The chip with the sensor functions at a resonance frequency which is detected by the reader initially during a frequency sweep. No dedicated power source is essential to operate the chips, but instead the chips are triggered into transmitting by the radio frequency signals transmitted from the reader. The frequency and output of transmission from the reader to the chips are variable. Stable communication can be performed without being affected by variation in the chips characteristics depending on manufacturing quality.
    Type: Application
    Filed: November 13, 2003
    Publication date: November 25, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Yoshiaki Yazawa, Masao Kamahori, Ken Takei, Takehiro Ohkawa, Hiroshi Yoshigi
  • Publication number: 20040140896
    Abstract: Provided is a portable information device having an RFID, the device being a device in which no effect is produced on original communication of the portable information device for which an EMC measure is taken, the device having good productivity, and the device keeping communication distance without damaging portability. A place where an antenna is set is located on the side of a battery cover of a battery receiving section to make the communication distance of an incorporated RFID long. A circuit configuration wherein a condenser for resonance is connected to both ends of the antenna coil and an IC is connected to an intermediate tap of the antenna coil is made so as to make it unnecessary that the resonance frequency of the RFID is individually adjusted and make the production of the RFID easy.
    Type: Application
    Filed: June 26, 2003
    Publication date: July 22, 2004
    Inventors: Takehiro Ohkawa, Hiroshi Yoshigi
  • Patent number: 6373708
    Abstract: The pattern line width of a coil is partially widened in a predetermined dimension and wiring patterns of a coil on the surface side and a coil on the rear side are arranged so as not to be in overlapped positions. Consequently, a direct current resistance of the coil can be reduced and an adverse influence by a self resonance of the coil on a communication can be reduced.
    Type: Grant
    Filed: August 13, 1999
    Date of Patent: April 16, 2002
    Assignees: Hitachi, Ltd., Hitachi Chemical Co., Ltd.
    Inventors: Kimiaki Ando, Takehiro Ohkawa, Kazuo Kaneko
  • Patent number: 6121623
    Abstract: A parallel radiation detector includes a plurality of radiation detecting elements, a plurality of preamplifiers for converting signals from the radiation detecting elements into voltage signals, a signal processing device for processing the voltage signals, a main control device for controlling the signal processing device to analyze the voltage signals, a display device for displaying analyzed results from the signal processing device, a storage device for storing signals, a plurality of a reset circuits corresponding to the plurality of preamplifiers, each reset circuit for generating a reset signal for returning the corresponding one of the preamplifiers to an initial state thereof when the voltage signal from the corresponding one of the preamplifiers reaches a predetermined voltage, and an inhibitor circuit for generating an inhibit signal for inhibiting the signal processing device from receiving and processing the voltage signals from the preamplifiers temporarily, based on the reset signal.
    Type: Grant
    Filed: October 2, 1998
    Date of Patent: September 19, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Isao Ochiai, Kimio Kanda, Takehiro Ohkawa
  • Patent number: 5999409
    Abstract: The pattern line width of a coil is partially widened in a predetermined dimension and wiring patterns of a coil on the surface side and a coil on the rear side are arranged so as not to be in overlapped positions. Consequently, a direct current resistance of the coil can be reduced and an adverse influence by a self resonance of the coil on a communication can be reduced.
    Type: Grant
    Filed: January 21, 1998
    Date of Patent: December 7, 1999
    Assignees: Hitachi, Ltd., Hitachi Chemical Co., Ltd.
    Inventors: Kimiaki Ando, Takehiro Ohkawa, Kazuo Kaneko
  • Patent number: 5594680
    Abstract: A contactless parallel data transfer device which is miniature, highly densed, and highly reliable having a coil block consisting of a first coil group installed in a portable memory and a coil block consisting of a second coil group installed in a data server for transferring access data in parallel between the portable memory (memory card, etc.) and the data server by contactless coupling, wherein the opposite coils of the first and second coil blocks are held close and opposite to each other on a contactless basis, and a parallel pulse group which is transferred in parallel between the both coil blocks is divided at least into a first parallel pulse group consisting of the first number of bits and a second parallel pulse group consisting of the second number of bits, and the parallel transfer timings of the both parallel pulse groups are different from each other, and an induced signal to the neighboring coils of each opposite coil pair of the first and second coil blocks is negated in the opposite phase.
    Type: Grant
    Filed: March 28, 1995
    Date of Patent: January 14, 1997
    Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.
    Inventors: Masatoshi Ohtake, Takeshi Tottori, Kazunari Nakagawa, Nobuo Hamamoto, Takehiro Ohkawa, Yutaka Kinebuti