Patents by Inventor Lawrence H. Conrad

Lawrence H. Conrad 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).

  • Variable magnification lens
    Patent number: 4406522
    Abstract: A variable magnification optical system comprising two lens components one on each side of an aperture stop with a positive lens element in each component connected for simultaneous movement to afford a change of 14.5.times. to 16.2.times. magnification in an object to image distance of 1108.96 mm.
    Type: Grant
    Filed: April 1, 1981
    Date of Patent: September 27, 1983
    Assignee: Minnesota Mining & Manufacturing Company
    Inventor: Lawrence H. Conrad
  • Auxiliary lens system for overhead projectors
    Patent number: 4350415
    Abstract: A pair of lenses placed one on each side of the projection head of a standard overhead projector can be utilized to change the focal length of the lens from 14 inches to 20 inches and produce the same image size at a projection distance of 15 feet as at a projection distance of only 9.4 feet.
    Type: Grant
    Filed: September 2, 1980
    Date of Patent: September 21, 1982
    Assignee: Minnesota Mining & Manufacturing Company
    Inventor: Lawrence H. Conrad
  • 6 Mm Ultra-fiche lens
    Patent number: 4310223
    Abstract: A short focal length high magnification lens system for projecting ultra-fiche images as a large aperture with substantially diffraction limited resolution in the visual spectrum and a compact vertex-to-vertex distance.
    Type: Grant
    Filed: October 9, 1979
    Date of Patent: January 12, 1982
    Assignee: Minnesota Mining & Manufacturing Company
    Inventor: Lawrence H. Conrad
  • Wide angle objective lens
    Patent number: 3994575
    Abstract: A wide angle objective lens comprising from front to rear a double-plano filter, a negative meniscus lens element, a second negative meniscus lens element, a cemented doublet consisting of a biconvex lens element and a biconcave lens element, a second cemented doublet consisting of a biconcave lens element and a positive meniscus lens element, a third cemented doublet consisting of two plano-convex lens elements, a negative meniscus lens element and a double-plano protective cover plate.
    Type: Grant
    Filed: September 15, 1975
    Date of Patent: November 30, 1976
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Lawrence H. Conrad