Patents by Inventor Philippe J. L. Belien

Philippe J. L. Belien 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).

  • Interferometer system with two wavelengths, and lithographic apparatus provided with such a system
    Patent number: 6122058
    Abstract: In an interferometer system, variations of the refractive index in the medium traversed by the measuring beam (123) can be detected by using two measuring beams (123, 125) having wavelengths which differ by a factor of three. For this choice of the wavelength ratio, the interference filters of the polarization elements, such as the beam splitter (127), the .lambda./4 plates (130, 131) and the antireflection coatings can be manufactured relatively easily, and the detection accuracy is increased.
    Type: Grant
    Filed: June 24, 1998
    Date of Patent: September 19, 2000
    Assignee: ASM Lithography B.V.
    Inventors: Jan E. Van Der Werf, Philippe J. L. Belien, Johannes C. N. Rijpers