Patents by Inventor Richard N. Pfisterer

Richard N. Pfisterer 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).

  • TV projection lens including a graded index element
    Patent number: 5392431
    Abstract: A projection TV lens (60) includes first (64), second (66), third (70), and fourth (72) element-groups counted in numerical order and arranged on a common optical axis (62). The first, third, and fourth groups each include at least one lens element. The first and third group has positive power and the fourth group has negative power. The second group includes a first lens element (67) having negative power and having a graded refractive index.
    Type: Grant
    Filed: October 5, 1992
    Date of Patent: February 21, 1995
    Inventor: Richard N. Pfisterer