Patents by Inventor Hiroaki Kumada

Hiroaki Kumada 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).

  • Composite film comprising low-dielectric resin and paraoriented aromatic polyamide
    Patent number: 6121171
    Abstract: Provided is a composite film comprising a continuous phase of para-oriented aromatic polyamide and a phase of low-dielectric resin, said film having a dielectric constant at 1 MHz of not more than 3.2 and a linear thermal expansion coefficient at 200 to 300.degree. C. of within .+-.50.times.10.sup.-6 /.degree.C. The composite film has characteristics such as a low dielectric constant, favorable mechanical strength, homogeneous structure, light weight, and a low linear thermal expansion coefficient, and the film is useful as a base substrate for a flexible printed circuit board.
    Type: Grant
    Filed: April 8, 1998
    Date of Patent: September 19, 2000
    Assignee: Sumitomo Chemical Company, Ltd.
    Inventors: Tsutomu Takahashi, Hiroaki Kumada
  • Prepreg process for producing the same and printed circuit substrate/board using the same
    Patent number: 6033765
    Abstract: The present invention provides a printed circuit substrate comprising a lightweight prepreg and a conductive layer. The prepeg having uniform formation, low linear thermal expansion coefficient and good mechanical strength, comprising a porous para-oriented aromatic polyamide film and a thermoplastic resin and/or a thermosetting resin, the porous para-oriented aromatic polyamide film being impregnated with the thermoplastic resin and/or the thermosetting resin, a process for producing the same, and a printed circuit substrate/board using the same.
    Type: Grant
    Filed: June 23, 1998
    Date of Patent: March 7, 2000
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Tsutomu Takahashi, Yoshifumi Tsujimoto, Hiroaki Kumada, Hiroyuki Sato
  • Prepreg, process for producing the same and printed circuit substrate/board using the same
    Patent number: 5851646
    Abstract: The present invention provides a lightweight prepreg having uniform formation, low linear thermal expansion coefficient and good mechanical strength, comprising a porous para-oriented aromatic polyamide film and a thermoplastic resin and/or a thermosetting resin, the porous para-oriented aromatic polyamide film being impregnated with the thermoplastic resin and/or the thermosetting resin, a process for producing the same, and a printed circuit substrate/board using the same.
    Type: Grant
    Filed: October 15, 1996
    Date of Patent: December 22, 1998
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Tsutomu Takahashi, Yoshifumi Tsujimoto, Hiroaki Kumada, Hiroyuki Sato