Patents by Inventor Koji Shigematsu

Koji Shigematsu 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: 6333781
    Abstract: An exposure apparatus and method and a high-performance projection optical system incorporated into the exposure apparatus. The projection optical system can be made doubly telecentric, while ensuring a large numerical aperture and large exposure field. The numerical aperture can vary via a variable aperture stop, and the aberrations are well-corrected over the range of numerical apertures. The projection optical system comprises, objectwise to imagewise, a first lens group G1 having positive refractive power and a subgroup G1p, second lens group G2 having negative refractive power and a subgroup G2n, a third lens group G3 having positive refracting power and at least one negative lens, a fourth lens group G4 having negative refracting power and a subgroup G4n, and fifth lens group G5 having positive refracting power and a subgroup G5p. Fifth lens group G5 includes a variable aperture stop AS which determines the image-side numerical aperture.
    Type: Grant
    Filed: July 16, 1998
    Date of Patent: December 25, 2001
    Assignee: Nikon Corporation
    Inventor: Koji Shigematsu
  • Patent number: 6259508
    Abstract: A projection optical system (20), exposure apparatus (10) incorporating same, and methods pertaining to same, for manufacturing devices and elements, such as integrated circuits, crystal displays, detectors, MR (magneto-resistive) heads, and the like. The projection optical system includes a first lens group (G1) having positive refractive power, a second lens group (G2) having negative refractive power, a third lens group (G3) having positive refractive power, a fourth lens group (G4) having negative refractive power and a least a first aspherical surface (ASP1), and a fifth lens group (G5) having positive refractive power and an aperture stop (AS). The projection optical system is designed such that paraxial rays traveling parallel to optical axis (A) imagewise to objectwise intersect the optical axis at a location (Q) between the fourth lens group and the fifth lens group.
    Type: Grant
    Filed: January 21, 1999
    Date of Patent: July 10, 2001
    Assignee: Nikon Corporation
    Inventor: Koji Shigematsu
  • Patent number: 6084723
    Abstract: The present invention relates to an exposure apparatus having a high-performance projection optical system having a relatively large numerical aperture and achieving bitelecentricity and superior correction of aberrations, particularly distortion, in a very wide exposure area. Particularly, the protection optical system according to the present invention is composed of a first lens group G.sub.1 with a positive refracting power, a second lens group G.sub.2 with a negative refracting power, a third lens group G.sub.3 with a positive refracting power, a fourth lens group G.sub.4 with a negative refracting power, and a fifth lens group G.sub.5 with a positive refracting power in order from the side of a first object R. The present invention is directed to finding of suitable ranges of focal lengths for the first to fifth lens groups G.sub.1 -G.sub.5, based on the above arrangement.
    Type: Grant
    Filed: August 29, 1996
    Date of Patent: July 4, 2000
    Assignee: Nikon Corporation
    Inventors: Hitoshi Matsuzawa, Koji Shigematsu, Kazumasa Endo, Yutaka Suenaga
  • Patent number: 5963472
    Abstract: A mask ROM is so configured as to read out information through the utilization of a cumulative time delay involved when a read-out signal applied to memory elements making connection between a word line WL1 and bit lines BL1 crossing the word line is passed through delay elements R1 to R7, that is, as to read out stored information on a time base, in which the conductions of switching transistors T1 to T8 are controlled by the outputs of the delay elements R1 to R7 and the information appearing at the bit line BL1 is sequentially read out at a predetermined time corresponding to a time delay resulting from the delay elements R1 to R7.
    Type: Grant
    Filed: July 22, 1998
    Date of Patent: October 5, 1999
    Assignee: NKK Corporation
    Inventors: Nobufumi Inada, Koji Shigematsu, Junichi Kitabuki, Tetsuya Hayashi
  • Patent number: 5848002
    Abstract: A mask ROM is so configured as to read out information through the utilization of a cumulative time delay involved when a read-out signal applied to memory elements making connection between a word line WL1 and bit lines BL1 crossing the word line is passed through delay elements R1 to R7, that is, as to read out stored information on a time base, in which the conductions of switching transistors T1 to T8 are controlled by the outputs of the delay elements R1 to R7 and the information appearing at the bit line BL1 is sequentially read out at a predetermined time corresponding to a time delay resulting from the delay elements R1 to R7.
    Type: Grant
    Filed: August 20, 1996
    Date of Patent: December 8, 1998
    Assignee: NKK Corporation
    Inventors: Nobufumi Inada, Koji Shigematsu, Junichi Kitabuki, Tetsuya Hayashi