Patents by Inventor Cindy Xing Qiu

Cindy Xing Qiu 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).

  • Methods and devices to determine the wavelength of a laser beam
    Patent number: 5999271
    Abstract: Methods for wavelength determination of a monochromatic light beam are described. The methods involve a detector unit containing at least one pair of photo detectors. One of the detectors in each detector pair is covered with a variable attenuator and the other is not covered by the variable attenuator. The optical transmission coefficient of the variable attenuator is a monotonic function of wavelength. Under illumination of a monochromatic light, the photocurrents produced in the detectors with and without the variable attenuator are compared. The relative values of the photocurrents are used to determine the wavelength of the monochromatic light.
    Type: Grant
    Filed: June 1, 1998
    Date of Patent: December 7, 1999
    Inventors: Ishiang Shih, Linh Ngo Phong, Shaolin Shi, Cindy Xing Qiu
  • Methods for wavelength discrimination of monochromatic light beams
    Patent number: 5824567
    Abstract: Methods for wavelength determination of a monochromatic beam are described. The methods involve a detector unit containing at least one variable filter and at least one pair of photo detectors. The detectors have photo sensitive regions with their areas varying with the position in one direction. The wavelength for maximum transmission of the variable filter varies in the same direction. By comparing the photo current values from the two detectors, wavelength of the incident beam is determined. Methods to construct wavelength discrimination junction photo detector pair and double barrier photo detector pair are also given.
    Type: Grant
    Filed: July 9, 1996
    Date of Patent: October 20, 1998
    Inventors: Ishiang Shih, Linh Ngo Phong, Cindy Xing Qiu, Philips Laou
  • Methods for wavelength discrimination of monochromatic light beams
    Patent number: 5703357
    Abstract: Methods for wavelength determination of a monochromatic beam are described. The methods involve a detector unit containing at least one variable filter and at least one pair of photo detectors. The detectors have photo sensitive regions with their areas varying with the position in one direction. The wavelength for maximum transmission of the variable filter varies in the same direction. By comparing the photo current values from the two detectors, wavelength of the incident beam is determined. Methods to construct wavelength discrimination junction photo detector pair and double barrier photo detector pair are also given.
    Type: Grant
    Filed: September 22, 1994
    Date of Patent: December 30, 1997
    Inventors: Ishiang Shih, Linh Ngo Phong, Cindy Xing Qiu, Philips Laou