Patents by Inventor David J. Warkentin

David J. Warkentin 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).

  • Publication number: 20030041447
    Abstract: A motion control system for reducing vibration in moving components. The system includes a position control drive and a vibration control drive. At least one position sensor is used to provide feedback signals which are in turn used to provide control signals for both the position control drive and the vibration control drive. In a preferred embodiment the motion control system is applied to a stage of an integrated circuit lithography step and scan machine. The position control drives are linear magnetic actuators and the vibration control drives are electroceramic actuators. A laser interferometer position monitoring system is used to measure the position, speed, and acceleration of the stage system. Actuators apply controlled forces (based on measurements from the position monitoring system) to each stage to control the motion of the stage. Signals from the interferometer position system are also used to control vibration.
    Type: Application
    Filed: March 29, 2002
    Publication date: March 6, 2003
    Inventors: Robert N. Jacques, David J. Warkentin
  • Publication number: 20030043876
    Abstract: The present invention provides a modular high repetition rate ultraviolet gas discharge laser light source for a production line machine. The system includes an enclosed and purged beam path with beam pointing control for delivery the laser beam to a desired location such as the entrance port of the production line machine. In preferred embodiments, the production line machine is a lithography machine and two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. This MOPA system is capable of output pulse energies approximately double the comparable single chamber laser system with greatly improved beam quality. A pulse stretcher more than doubles the output pulse length resulting in a reduction in pulse power (mJ/ns) as compared to prior art laser systems.
    Type: Application
    Filed: August 30, 2002
    Publication date: March 6, 2003
    Inventors: Leonard Lublin, David J. Warkentin, Palash P. Das, Brian C. Klene, R. Kyle Webb, Herve A. Besaucele, Ronald L. Spangler, Richard L. Sandstrom, Alexander I. Ershov, Shahryar Rokni
  • Patent number: 4942767
    Abstract: A micromachined diaphragm is positioned across a gap from an end of an optic fiber. The optic fiber and the diaphragm are integrally mounted. The end of the optic fiber provides a local reference plane which splits light carried through the fiber toward the diaphragm. The light is split into a transmitted part which is subsequently reflected from the diaphragm, and a locally reflected part which interferes with the subsequently diaphragm reflected part. The interference of the two reflective parts forms an interference light pattern carried back through the fiber to a light detector. The interference pattern provides an indication of diaphragm deflection as a function of applied pressure across the exposed side of the diaphragm. A detection of magnitude and direction of diaphragm deflection is provided by use of a second fiber positioned across the gap from the diaphragm. The second fiber provides an interference pattern in the same manner as the first fiber but with a phase shift.
    Type: Grant
    Filed: June 2, 1989
    Date of Patent: July 24, 1990
    Assignee: Massachusetts Institute of Technology
    Inventors: Joseph H. Haritonidis, Stephen D. Senturia, David J. Warkentin, Mehran Mehregany
  • Patent number: 4926696
    Abstract: A thin diaphragm receives pressure across one side and faces a beam splitter on the other side. The beam splitter is integrally attached to the diaphragm and serves as a local optical reference plane for the entire assembly. Coherent light from a light source is partially reflected at the beam splitter. The remainder of the light is reflected from the diaphragm. The reflected beams recombine at a detection point and have a phase difference which is a function of the amount of deflection of the diaphragm. The detected recombined beams are indicative of the deflection of the diaphragm. Optical calibration of the aseembly is a function of the distance between the diaphragm and beam splitter which remains as predefined because the beam splitter is integral with the diaphragm. A vent in the small cavity formed between the diaphragm and beam splitter enables the diaphragm to sense small pressures with increased sensitivity.
    Type: Grant
    Filed: November 19, 1986
    Date of Patent: May 22, 1990
    Assignee: Massachusetts Institute of Technology
    Inventors: Joseph H. Haritonidis, Stephen D. Senturia, David J. Warkentin, Mehran Mehregany