Patents by Inventor Leslie D. Foo

Leslie D. Foo 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: 6231198
    Abstract: An optical integrator comprising a two dimensional array of mirror segments formed from an off-axis section of a parent parabolic surface. The mirror segments are arranged so that the focus of each mirror segment is in a plane. Incident collimated radiation is coaxial with the system axis. The secondary point source images are substantially aberration free.
    Type: Grant
    Filed: February 17, 1998
    Date of Patent: May 15, 2001
    Assignee: Nikon Corporation
    Inventor: Leslie D. Foo
  • Patent number: 6022114
    Abstract: An anamorphic system and method having first and second reflective anamorphic surfaces producing different magnifications in orthogonal directions in a collimated beam of radiation incident on the first anamorphic surface. The anamorphic surfaces have parabolic cross-sections in the two orthogonal directions. The parabolic cross-sections have base radii of curvatures and the magnifications in the first and second directions are determined by the ratio of the base radii of curvatures in the first and second directions.
    Type: Grant
    Filed: May 1, 1998
    Date of Patent: February 8, 2000
    Assignee: Nikon Corporation
    Inventor: Leslie D. Foo
  • Patent number: 5880879
    Abstract: A low cost objective lens system that provides complete axial color correction with no substantial residual color dependent aberrations such as spherochromatism or chromatic coma. The objective lens system includes a first lens element having an aspherical lens surface and a second lens element having a diffractive optical surface and an aperture disposed between the first and second lens elements. The axial separation of the aspherical lens surface and the diffractive optical surface may be determined by the condition 0.5<L.sub.A /efl<1.25 where L.sub.A is the axial distance from the lens element with the aspherical surface to the lens element with the diffractive optical surface and efl is the effective focal length of the objective lens system. The diffractive optical surface is optically dispersive and is preferably placed on the refractive lens element in the system having the highest optical power.
    Type: Grant
    Filed: August 26, 1997
    Date of Patent: March 9, 1999
    Assignee: Nikon Corporation
    Inventor: Leslie D. Foo
  • Patent number: 5844724
    Abstract: A wide angle zoom lens configuration which provides a compact two component lens configuration for use in an optical system such as a camera having a zoom ratio substantially over two, an angle of view of at least 94.degree. and which is well corrected with respect to optical aberrations. Such a zoom lens includes, in order from the object side to the image side a first group of lens elements with an overall negative refractive power and a second group of lens elements with an overall positive refractive power. The first group of lens elements includes, in order from the object side, three lens elements each with a negative refractive power and a fourth meniscus shaped lens element with a positive refractive power having a convex surface facing the object side. The first group of lens elements includes at least one lens element having an aspherical surface.
    Type: Grant
    Filed: September 19, 1997
    Date of Patent: December 1, 1998
    Assignee: Nikon Corporation
    Inventor: Leslie D. Foo
  • Patent number: 5621574
    Abstract: Axial gradient index of refraction lens elements are used in a lens system, for instance for a photographic objective lens, to correct monochromatic and chromatic lens aberrations, thereby reducing the number of lens elements required to achieve good optical performance in the overall lens design compared to for instance a lens system using aspheric lenses. The gradient index (GRIN) lens elements are bi-convex and/or meniscus type lens elements. The large refractive index gradients as well as large dispersion value gradients provide aberration correction in the overall lens system. A high aperture ratio lens system uses six lens elements where the first and last lens elements are positive power lens elements having refractive index and/or dispersion gradients along the optical axis.
    Type: Grant
    Filed: March 29, 1995
    Date of Patent: April 15, 1997
    Assignee: Nikon Corporation
    Inventor: Leslie D. Foo
  • Patent number: 5515207
    Abstract: A reduction projection system (10) characterized by large numerical aperture has an unobscured optical path without the need to resort to truncated lens elements. The system includes first and second reduction stages. The first reduction stage includes a first mirror group (20) and a first lens group (30). The second reduction stage includes a second mirror group (40) and a second lens group (50). Together, the first mirror group and the first lens group form an intermediate reduced image of the object at an intermediate image region (70). The second mirror group and the second lens group form a further reduced image at an image plane (15).
    Type: Grant
    Filed: November 3, 1993
    Date of Patent: May 7, 1996
    Assignee: Nikon Precision Inc.
    Inventor: Leslie D. Foo