Patents by Inventor Tomohiko Oota

Tomohiko Oota 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: 6687321
    Abstract: A digital PLL circuit comprises a variable-frequency ring oscillator, a frequency divider for frequency-dividing the output signal of the ring oscillator, a phase comparator for comparing the frequency-divided output of the frequency divider with a phase reference signal, and a control signal generator for generating a control signal corresponding to the comparison output of the phase comparator and supplying the control signal to the ring oscillator.
    Type: Grant
    Filed: September 20, 2000
    Date of Patent: February 3, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Kada, Tomohiko Oota
  • Patent number: 5938842
    Abstract: A puller and method for crystal growth using the Czochralski technique in which a temperature profile and a history of thermal conditions of a growing crystal is controllable with ease and a good accuracy, which puller comprises a crucible containing raw material, heater for melting by heating the raw material and a heat insulating cylinder surrounding them, the heat insulating cylinder being cross-sectionally divided by an annular separation gap or gaps into parts and which method is applicable to growth of such a single crystal as of silicon, germanium, GaP, GaAs or InP in the puller. Methods for controlling a temperature profile and a history of thermal conditions of a growing crystal using the czochralski technique in the puller.
    Type: Grant
    Filed: June 4, 1998
    Date of Patent: August 17, 1999
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Tomohiko Oota, Kiyotaka Takano, Masanori Kimura
  • Patent number: 5817171
    Abstract: A puller and method for crystal growth using the Czochralski technique in which a temperature profile and a history of thermal conditions of a growing crystal is controllable with ease and a good accuracy, which puller comprises a crucible containing raw material, heater for melting by heating the raw material and a heat insulating cylinder surrounding them, the heat insulating cylinder being cross-sectionally divided by an annular separation gap or gaps into parts and which method is applicable to growth of such a single crystal as of silicon, germanium, GaP, GaAs or InP in the puller. Methods for controlling a temperature profile and a history of thermal conditions of a growing crystal using the czochralski technique in the puller.
    Type: Grant
    Filed: May 31, 1996
    Date of Patent: October 6, 1998
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Tomohiko Oota, Kiyotaka Takano, Masanori Kimura