Patents by Inventor Kouji Sumi

Kouji Sumi 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).

  • Piezoelectric thin-film device process for manufacturing the same, and ink-jet recording head using the same
    Patent number: 6013970
    Abstract: A piezoelectric thin-film device includes: a substrate and a piezoelectric thin film formed on the substrate, wherein a thickness of the piezoelectric thin film is 1 to 10 .mu.m, a crystal grain size of the piezoelectric thin film is 0.05 to 1 .mu.m, and a surface roughness (Rmax) of the piezoelectric thin film is no more than 1 .mu.m.
    Type: Grant
    Filed: March 6, 1997
    Date of Patent: January 11, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Tsutomu Nishiwaki, Kouji Sumi, Masami Murai, Masato Shimada