Patents by Inventor Kathleen Marie Humpal

Kathleen Marie Humpal 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: 5942280
    Abstract: A method of making a ceramic retroreflective element having enhanced strength and increased retained reflectivity. The method of the present invention comprises forming retroreflective elements by the following steps:a) providing glass flakes;b) coating said glass flakes with a first barrier layer yielding coated glass flakes;c) providing optical elements;d) optionally coating said optical elements with a second barrier layer;e) blending said optical elements and said coated glass flakes;f) heating said optical elements and said coated glass flakes to spheroidize said flakes while agitating said optical elements and said coated glass flakes;g) further heating said optical elements and said spheroidized glass flakes to partially embed said optical elements in said spheroidized flakes while agitating said optical elements and said spheriodized flakes; andh) cooling said spheroidized flakes having partially embedded optical elements.
    Type: Grant
    Filed: September 16, 1997
    Date of Patent: August 24, 1999
    Assignee: 3M Innovative Properties Company
    Inventors: James Patrick Mathers, Kathleen Marie Humpal