Patents by Inventor Alfred Stephens

Alfred Stephens 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).

  • Gray interference pigment and process for producing the same
    Patent number: 5693134
    Abstract: An interference pigment comprising a platelet-shaped substrate coated with titanium dioxide and additionally oxidic compounds of copper and manganese, whereby the pigment powder color is dark gray.
    Type: Grant
    Filed: December 29, 1994
    Date of Patent: December 2, 1997
    Assignee: Merck Patent Gesellschaft mit beschrankter Haftung
    Inventor: Alfred Stephens