Patents by Inventor Ytsen Wielstra

Ytsen Wielstra 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).

  • Method of marking a surface of an object by means of a laser light
    Patent number: 5554196
    Abstract: Method of marking a surface of an object by means of a laser light beam.A description is given of a method of decorating or marking, for example, synthetic resin objects by means of an UV-laser or IR-laser by coating the object with a layer of a dye precursor and a coupler in a binder. For the precursor use is made of a heterocyclic mono- or bis-arylsulphonylhydrazone and for the coupler use is made of, for example, an indole, aniline, pyrazoline or malonitrile, so that after irradiation with UV-laser light or IR-laser light an azo-dye (XXX) is formed.
    Type: Grant
    Filed: August 1, 1995
    Date of Patent: September 10, 1996
    Assignee: U.S. Philips Corporation
    Inventor: Ytsen Wielstra