Patents by Inventor Yoshiaki Nakata

Yoshiaki Nakata 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: 6281519
    Abstract: A quantum semiconductor memory device includes a quantum structure formed on a substrate, wherein the quantum structure includes a plurality of self-organized quantum dots forming a strained heteroepitaxial system with respect to the substrate and an accumulation layer formed adjacent to the self-organized quantum dots, and wherein the self-organized quantum dots are formed of a semiconductor crystal having a composition set such that quantum levels of the self-organized quantum dots are located higher than a conduction band of the accumulation layer.
    Type: Grant
    Filed: March 22, 1999
    Date of Patent: August 28, 2001
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Sugiyama, Yoshiaki Nakata
  • Publication number: 20010005516
    Abstract: A die for manufacturing resin pellets capable of processing a die plate easily, and achieving simplification of a construction of heat channels and enhancement of heating efficiency. A die 1 for manufacturing resin pellets provided with a number of nozzle orifices 7 in the outer surface of the die, there are provided a plurality of rows of heat channels 8 which extend in a direction crossing the resin channels 5 in the vicinity of the outer surface of the die and are arranged along the resin channels 5. At least one of an introducing course and a discharging course for a heat medium in the plurality of heat channels 8.
    Type: Application
    Filed: December 19, 2000
    Publication date: June 28, 2001
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Yasuo Yoshii, Shinichi Fukumizu, Osamu Ikeda, Nobuhiro Yamasaki, Yoshiaki Nakata
  • Patent number: 5936258
    Abstract: A wavelength-domain-multiplication memory comprises a first semiconductor layer including a first conductivity type impurity, a carrier barrier semiconductor layer formed on the first semiconductor layer, and quantum dots formed in the carrier barrier semiconductor layer.
    Type: Grant
    Filed: April 15, 1996
    Date of Patent: August 10, 1999
    Assignee: Fujitsu Limited
    Inventors: Kenichi Imamura, Shun-ichi Muto, Naoto Horiguchi, Yoshihiro Sugiyama, Yoshiaki Nakata
  • Patent number: 5905297
    Abstract: A semiconductor integrated circuit device including: an off-substrate having a semiconductor surface with a plurality of steps each having a height of one monolayer and extending in one direction; a wiring layer formed on the semiconductor surface of the off-substrate and made of semiconductor material, the wiring layer including a plurality of conductive stripe regions and high resistance strip regions disposed in a stripe pattern, each stripe region extending in a direction parallel with the steps, and the conductive stripe regions and the high resistance stripe regions both having lattice structures identical to those of underlying surfaces; and semiconductor elements formed on the wiring layer and electrically connected to the conductive stripe regions, the semiconductor elements including semiconductor regions with lattice structures identical to those of the conductive stripe regions.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: May 18, 1999
    Assignee: Fujitsu Limited
    Inventors: Toshihiko Mori, Yoshiaki Nakata
  • Patent number: 5812574
    Abstract: An optical semiconductor device includes a plurality of quantum structures in an active layer thereof, wherein each of the quantum structures is confined in at least two of the three, mutually perpendicular dimensions, and wherein at least two of the quantum structures are separated with a distance that allows tunneling of carriers therebetween.
    Type: Grant
    Filed: July 18, 1997
    Date of Patent: September 22, 1998
    Assignee: Fujitsu Limited
    Inventors: Atsushi Takeuchi, Yoshiaki Nakata
  • Patent number: 5756129
    Abstract: A filter member includes a breaker plate having an increased filtering area without any deterioration in screen back-up capability. This filter member is adapted to filter off impurities of resin melt and is disposed in a resin passage. The filter member includes a screen and a breaker plate for backing up the screen. The breaker plate has resin passageways in the form of elongated slits extending as intersecting the flow direction of resin material.
    Type: Grant
    Filed: February 29, 1996
    Date of Patent: May 26, 1998
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Yasuo Yoshii, Nobuki Nagami, Nobuhiro Yamasaki, Yoshiaki Nakata, Shinichi Fukumizu, Osamu Ikeda
  • Patent number: 5705408
    Abstract: A semiconductor integrated circuit device including: an off-substrate having a semiconductor surface with a plurality of steps each having a height of one monolayer and extending in one direction; a wiring layer formed on the semiconductor surface of the off-substrate and made of semiconductor material, the wiring layer including a plurality of conductive stripe regions and high resistance strip regions disposed in a stripe pattern, each stripe region extending in a direction parallel with the steps, and the conductive stripe regions and the high resistance stripe regions both having lattice structures identical to those of underlying surfaces; and semiconductor elements formed on the wiring layer and electrically connected to the conductive stripe regions, the semiconductor elements including semiconductor regions with lattice structures identical to those of the conductive stripe regions.
    Type: Grant
    Filed: September 25, 1996
    Date of Patent: January 6, 1998
    Assignee: Fujitsu Limited
    Inventors: Toshihiko Mori, Yoshiaki Nakata
  • Patent number: 5436468
    Abstract: On a substrate having a surface slightly tilted by an angle .alpha. within the range of from 0.5 to 10 degrees from the (110) plane in the <00-1> direction, a superlattice structure having a periodicity in both <110> and <001> directions is formed. Various band structures are possible by selecting an appropriate constituent material and periodicity for the superlattice structure. When current flows in a direction without periodicity, a very high mobility is obtained as a result of suppressed alloy scattering. If current is caused to flow in a direction with periodicity, and the periodicity is properly selected, optical phonon scattering can also be suppressed.
    Type: Grant
    Filed: September 19, 1994
    Date of Patent: July 25, 1995
    Assignee: Fujitsu Limited
    Inventors: Yoshiaki Nakata, Osamu Ueda, Satoshi Nakamura
  • Patent number: 5392307
    Abstract: An active layer having a predetermined effective band gap, a predetermined effective refractive index, and a predetermined thickness is sandwiched between a first clad layer and a second clad layer. Each of the clad layers has an effective band gap wider than that of the active layer, an effective refractive index lower than that of the active layer, and a predetermined thickness. On the first clad layer, there is disposed a first stack structure doped to a first conductivity type, which alternately includes a layer of a high refractive index and a layer of a low refractive index, and has a discontinuity of a band of the first conductivity type made quite smaller than that of a band of a second conduction type.
    Type: Grant
    Filed: August 31, 1993
    Date of Patent: February 21, 1995
    Assignee: Fujitsu Limited
    Inventors: Yoshihiro Sugiyama, Yoshiaki Nakata
  • Patent number: RE37681
    Abstract: A filter member includes a breaker plate having an increased filtering area without any deterioration in screen back-up capability. This filter member is adapted to filter off impurities of resin melt and is disposed in a resin passage. The filter member includes a screen and a breaker plate for backing up the screen. The breaker plate has resin passageways in the form of elongated slits extending as intersecting the flow direction of resin material.
    Type: Grant
    Filed: May 26, 2000
    Date of Patent: April 30, 2002
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Yasuo Yoshii, Nobuki Nagami, Nobuhiro Yamasaki, Yoshiaki Nakata, Shinichi Fukumizu, Osamu Ikeda