Patents by Inventor Tomawaki Takahashi

Tomawaki Takahashi 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).

  • Projection lens system and apparatus
    Patent number: 6008884
    Abstract: A high-performance dioptric reduction projection lens and projection exposure apparatus and projection exposure method using same. The projection lens includes six lens groups and has a positive negative positive negative positive refractive power arrangement. The third and fifth lens groups have overall positive refractive power and include at least three lens elements having positive refractive power. The fourth lens group has negative refractive power and includes at least three lens elements having negative refractive power. At least one lens element in either the fourth lens group or the fifth lens group includes an aspheric surface. The projection lens preferably satisfies at least one of a number of design conditions.
    Type: Grant
    Filed: April 27, 1998
    Date of Patent: December 28, 1999
    Assignee: Nikon Corporation
    Inventors: Kotaro Yamaguchi, Kiyoshi Hayashi, Tomawaki Takahashi