Patents by Inventor Shizue Itoh

Shizue Itoh 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).

  • Surface-hardened titanium material, surface hardening method of titanium material, watchcase decoration article, and decoration article
    Patent number: 6270914
    Abstract: The invention provides a method of surface hardening a titanium material wherein titanium-aluminum alloy powders or aluminum oxide powders are brought into contact with the surface of the titanium material, and a heat treatment is applied thereto, causing aluminum contained in the powders to be diffused in the surface of the titanium material so that intermetallic compounds such as Ti3Al, TiAl, and the like are formed inmediately underneath the surface of the titanium material, thereby enhancing surface hardness without causing surface exfoliation. The invention also provides a surface-hardened titanium-base material, and decorative articles and watchcases, composed of the surface-hardened titanium-base material, which are substantially impervious to scratches, and not prone to cause metallic allergy.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: August 7, 2001
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Naoto Ogasawara, Yasumasa Kusano, Shizue Itoh, Kotaro Ishiyama