Patents by Inventor Masaichi Nagai

Masaichi Nagai 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: 6127210
    Abstract: A simple and convenient method of manufacturing a CMOS TFT semiconductor circuit device wherein a doping layer doped into a first conductivity type without a mask is compensated with a dopant of a second conductivity type having a high density so that the conductivity type of the doping layer of first conductivity type is inverted into the second conductivity type, and further, in order to carry out the inversion of the conductivity type by the compensation easily and reliably, the surface density of the dopant of the doping layer of first conductivity type is reduced prior to compensating with the dopant of second conductivity type.
    Type: Grant
    Filed: October 3, 1996
    Date of Patent: October 3, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Akio Mimura, Hiroshi Suga, Masaichi Nagai, Youmei Shinagawa, Isao Ikuta
  • Patent number: 5583840
    Abstract: An optical information handling device in which reflectivity of the conventional reproduction-only type optical disk is lowered to 60% or less and is made equal to the reflectivity of write-once type and rewritable type optical disks, whereby interchangeability in these of these disks is possible.
    Type: Grant
    Filed: December 28, 1994
    Date of Patent: December 10, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Minemura, Yoshio Sato, Nobuyoshi Tsuboi, Hisashi Andoh, Masaichi Nagai, Isao Ikuta, Yoshimi Kato, Yoshihito Maeda, Tatsuya Sugita, Yutaka Sugita
  • Patent number: 5572502
    Abstract: An optical disk apparatus includes a recording method in which at least one of the scanning position, the irradiation time, the irradiation start point and the irradiation power of a light beam is arbitrarily changed, and a method and apparatus in which information is represented by a plurality of recording marks without being limited to two kinds of recording and erasion. In order to prevent overlapping recording/erasion, a recording clock generating unit delays a reference clock signal to generate a recording clock signal and a recording control unit transfers user data to an optical head in synchronism with the recording clock signal so that it is recorded on an optical disk. Also, the amount of delay is recorded to enable sure reading or reproduction. At the time of reading, a servo mark detection signal is divided to generate a clock signal having a variable frequency, thereby realizing an optical disk for which high-precision recording/reproduction is possible.
    Type: Grant
    Filed: September 28, 1994
    Date of Patent: November 5, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Atsuko Naruse, Yoshihito Maeda, Yoshimi Kato, Isao Ikuta, Hisashi Andoh, Masaichi Nagai, Yoshio Sato, Tetsuya Fushimi, Hiroyuki Minemura, Tatsuya Sugita
  • Patent number: 5484686
    Abstract: The present invention provides an optical recording medium using an amorphous-crystalline phase-change for recording and erasing, wherein reflectivity of an optical recording medium-constituting recording film in an amorphous state is larger than that of the optical recording medium-constituting recording film in a crystalline state, or wherein absorptivity of an optical recording medium-constituting recording film in an amorphous state is smaller than that of the optical recording medium-constituting recording film in a crystalline state.
    Type: Grant
    Filed: March 4, 1994
    Date of Patent: January 16, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihito Maeda, Isao Ikuta, Hisashi Andoh, Masaichi Nagai, Yoshimi Katoh, Yoshio Sato, Nobuyoshi Tsuboi, Hiroyuki Minemura
  • Patent number: 5475656
    Abstract: The information processor uses a portable memory formed on a transparent substrate which is able to be overwritten by laser power modulation system. The memory includes a disk type recording medium rotatably incorporated within a thin case, and carries out write/read/erase by means of a first magnetic field application device, a second magnetic field application device, and an optical head radiating light through the case which has at least a transparent light-incident portion. The case includes therein a rotation means for rotating the recording medium within the case, thereby enabling even further reduction in size of the information processor.
    Type: Grant
    Filed: September 5, 1991
    Date of Patent: December 12, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Yoshio Sato, Nobuyoshi Tsuboi, Hiroyuki Minemura, Hisashi Andoh, Masaichi Nagai, Isao Ikuta, Yoshimi Kato, Yoshihito Maeda, Tatsuya Sugita, Yutaka Sugita
  • Patent number: 5420845
    Abstract: High density optical information recording even at room temperature is achieved by control of the diameter of crystalline portions exhibiting quantum size effects of fine semiconductor particles distributed in a dielectric matrix, using the non-crystalline to crystalline phase transition of the fine particles. The quantum size effects mean that the optical properties of the medium depend on the diameter of the crystalline portions. Various methods of recording, reproducing and erasing information using this optical recording medium are possible. The invention is applicable to other optical devices.
    Type: Grant
    Filed: June 18, 1992
    Date of Patent: May 30, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihito Maeda, Isao Ikuta, Masaichi Nagai, Yoshimi Kato, Hisashi Andoh, Nobuo Tsukamoto
  • Patent number: 5371730
    Abstract: The invention relates to an optical memory in which an optical recording medium is built in a case, and also to a memory apparatus. Recording, reproducing and erasing operations are performed by irradiating light via a transparent portion of the case onto the built-in optical recording medium. The optical recording medium built in the case has face vibrations with respect to the case, because it is moved within the case. The present invention is characterized by employing such a construction for optically mitigating irregular fluctuation in reflectivity caused by this face vibration. In the optical memory of the present invention, the reflectivity fluctuation caused by an interference effect made between reflection light from the case and air, and also reflection light from the optical recording medium and air due to the relative deviation in the face vibrations, may be reduced by antireflection films provided in the case and the optical recording medium.
    Type: Grant
    Filed: November 28, 1990
    Date of Patent: December 6, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihito Maeda, Isao Ikuta, Masaichi Nagai, Yoshimi Katou, Hisashi Andoh, Nobuyoshi Tsuboi, Hiroyuki Minemura, Tatsuya Sugita, Yoshio Sato, Yutaka Sugita
  • Patent number: 5317556
    Abstract: There is provided a compact and thin optical disk unit as a memory unit suitable for a portable computer such as a book type computer and a portable recording/reproducing apparatus. In the optical disk unit, the diameter of an objective lens is limited and a beam shaping prism, a beam splitter, a mirror and a 1/4 wavelength plate are formed into a unitary structure to make easy the optical axis adjustment of an optical head and ensure highly accurate assembling.
    Type: Grant
    Filed: December 5, 1990
    Date of Patent: May 31, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Nobuyoshi Tsuboi, Yoshio Sato, Hiroyuki Minemura, Hisashi Andoh, Masaichi Nagai, Isao Ikuta, Yoshimi Katou, Yoshihito Maeda, Tatsuya Sugita, Yutaka Sugita
  • Patent number: 5274612
    Abstract: The information processor uses a portable memory which is able to be overwritten by laser power modulation system. The memory includes a disk type recording medium incorporated rotatably in a thin case, and carries out write/read/erase by means of a first magnetic field application device, a second magnetic field application device, and an optical head radiating light through this case.
    Type: Grant
    Filed: August 5, 1991
    Date of Patent: December 28, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Yoshio Sato, Nobuyoshi Tsuboi, Hiroyuki Minemura, Hisashi Andoh, Masaichi Nagai, Isao Ikuta, Yoshimi Kato, Yoshihito Maeda, Tatsuya Sugita, Yutaka Sugita
  • Patent number: 5187052
    Abstract: An optical recording medium, which comprises a recording layer capable of reversibly undergoing a phase change between a crystalline state and an amorphous state by irradiation of an electromagnetic energy, the crystalline state of the recording layer being composed of a single phase of substantially a three-component compound or a higher multi-component compound can attain high speed recording and high speed erasing that cannot be obtained with the conventional optical recording medium.
    Type: Grant
    Filed: February 10, 1992
    Date of Patent: February 16, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihito Maeda, Toshiki Kaneko, Masaichi Nagai, Hisashi Andoh, Yoshimi Katou, Isao Ikuta, Ryuji Watanabe
  • Patent number: 4668591
    Abstract: A matrix for magnetic separators which comprises wire or ribbon of a crystalline magnetic alloy having a fine-grained structure and a supersaturated solid solution structure.
    Type: Grant
    Filed: March 11, 1985
    Date of Patent: May 26, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Tetsuroh Minemura, Joo Ishihara, Masaichi Nagai, Takeo Tamamura
  • Patent number: 4651172
    Abstract: In an information recording medium having a recording layer for recording information by heating through incoming energy, at least one of an interference layer and an absorption layer for the incoming energy is provided on the energy-incoming side of the recording layer to reduce the reflected energy from the information recording medium and increase the quantity of heat input into the recording layer. The temperature of the recording layer is rapidly enhanced, and rapid writing is made possible thereby. Writing or erasing can be made with less incoming energy, and thus the writing sensitivity or erasing sensitivity of the information recording medium can be increased.
    Type: Grant
    Filed: November 26, 1985
    Date of Patent: March 17, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Ryuji Watanabe, Tetsuro Minemura, Tetsuo Ito, Hisashi Ando, Yoshihito Maeda, Masaichi Nagai, Seiki Shimizu, Kiyoshi Konno, Toshiki Kaneko
  • Patent number: RE36624
    Abstract: The present invention provides an optical recording medium using an amorphous-crystalline phase-change for recording and erasing, wherein reflectivity of an optical recording medium-constituting recording film in an amorphous state is larger than that of the optical recording medium-constituting recording film in a crystalline state, or wherein absorptivity of an optical recording medium-constituting recording film in an amorphous state is smaller than that of the optical recording medium-constituting recording film in a crystalline state.
    Type: Grant
    Filed: January 15, 1998
    Date of Patent: March 21, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihito Maeda, Isao Ikuta, Hisashi Andoh, Masaichi Nagai, Yoshimi Katoh, Yoshio Sato, Nobuyoshi Tsuboi, Hiroyuki Minemura