Patents by Inventor Masaji Dohi

Masaji Dohi 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: 5891512
    Abstract: A solution of precursor of a pyroelectric material, e.g. BaSrTiO.sub.3, is coated on a surface of a silicon wafer having an array of mesas corresponding to infrared sensor elements to be formed thereon, and the pyroelectric material precursor coating is dried and then is subjected to a heat treatment for converting thereof into a pyroelectric thin film (sol-gel process). The internal stress in the pyroelectric thin film formed as thick as 1 .mu.m by repeating the process concentrates in the region (groove) between the mesas, hence cracks occurring in the film in connection with the stress are limited within the region and the portions of the film on the mesas can be free from the cracks. The pyroelectric thin film in the groove is selectively removed. An infrared image sensing device comprising sensor elements of uniform characteristics and high reliability is provided.
    Type: Grant
    Filed: August 28, 1997
    Date of Patent: April 6, 1999
    Assignee: Fujitsu Limited
    Inventors: Satoshi Kawata, Masaji Dohi, Yoichiro Sakachi, Hiroshi Daiku
  • Patent number: 5852648
    Abstract: A display signal of high contrast is generated by processing an image signal that is acquired from a camera such as an infra-red or X-ray camera.
    Type: Grant
    Filed: May 22, 1997
    Date of Patent: December 22, 1998
    Assignee: Fujitsu Ltd.
    Inventors: Yoshihiro Miyamoto, Masaji Dohi
  • Patent number: 5589687
    Abstract: An infrared detection device has a substrate with a plurality of hollow mesas and a pyroelectric thin film formed on the surface having the mesas.
    Type: Grant
    Filed: March 30, 1995
    Date of Patent: December 31, 1996
    Assignee: Fujitsu Limited
    Inventors: Satoshi Kawata, Masaji Dohi, Yoichiro Sakachi, Hiroshi Daiku
  • Patent number: 5227887
    Abstract: An image sensing device uses photodiodes arranged in a matrix. Each photodiode is connected to one of p serially-coupled input gate and transfer gate combinations, were p is an integer greater than or equal to 2. Channel terminals of the p transfer gates are commonly-coupled to a serially-coupled storage gate and output switch combination. The serially-coupled storage gate and output switch combination and its associated p input gate and transfer gate combinations can be repeatedly provided in rows and columns, and addressed so that pixels determined by the photodiodes can be serially output from the image sensing device. Among other advantages, by using serially-coupled input gate and transfer gate combinations, the area provided for a storage gate can be increased so that the sensitivity, dynamic range and/or signal-to-noise ratio is increased relative to conventional devices.
    Type: Grant
    Filed: December 20, 1991
    Date of Patent: July 13, 1993
    Assignee: Fujitsu Limited
    Inventors: Masaji Dohi, Kenji Awamoto, Kazuya Kubo, Yuichiro Ito
  • Patent number: 4434441
    Abstract: A charge injection device sensing an optical radiation pattern is driven at an operation sequence where the charge holding mode is inserted between the charge storing/readout mode and the charge injection mode. The charge holding period is effective for picture elements influenced by charges injected into the substrate after the readout operation placed spacially far and timed. The problem of cross-talk at high speed operation is resolved.
    Type: Grant
    Filed: November 23, 1981
    Date of Patent: February 28, 1984
    Assignee: Fujitsu Limited
    Inventors: Hiroyuki Ishizaki, Yoshiki Tsujino, Masaji Dohi