Patents by Inventor David L. Spears

David L. Spears 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).

  • Patent number: 7920261
    Abstract: A particle detection system that images and detects particles in a fluid flow stream through use of detector array(s) is described. The detection system may include light source arrays that may selectively illuminate a particle in a fluid stream. The detection system may also include a detector array employing smart binning to read the measured signals. The smart binning of the detector array may be achieved through knowledge of an exact particle location provided by a position sensitive detector. The detector array(s) may be low cost based on intelligence built into the system. This particle detection system may be particularly useful for detection and discrimination of different particle types since the read-out of the particle signals can be accomplished with low noise and can be flexible enough to optimize the read out measurements for each particle. The particle detection system may be used, for example, in early warning contamination detection systems and manufacturing processes.
    Type: Grant
    Filed: February 11, 2008
    Date of Patent: April 5, 2011
    Assignee: Massachusetts Institute of Technology
    Inventors: Thomas H. Jeys, Antonio Sanchez-Rubio, Richard J. Molnar, Robert K. Reich, Jinendra K. Ranka, David L. Spears, Richard M. Osgood, III
  • Publication number: 20100053614
    Abstract: A particle detection system that images and detects particles in a fluid flow stream through use of detector array(s) is described. The detection system may include light source arrays that may selectively illuminate a particle in a fluid stream. The detection system may also include a detector array employing smart binning to read the measured signals. The smart binning of the detector array may be achieved through knowledge of an exact particle location provided by a position sensitive detector. The detector array(s) may be low cost based on intelligence built into the system. This particle detection system may be particularly useful for detection and discrimination of different particle types since the read-out of the particle signals can be accomplished with low noise and can be flexible enough to optimize the read out measurements for each particle. The particle detection system may be used, for example, in early warning contamination detection systems and manufacturing processes.
    Type: Application
    Filed: February 11, 2008
    Publication date: March 4, 2010
    Inventors: Thomas H. Jeys, Antonio Sanchez-Rubio, Richard J. Molnar, Robert K. Reich, Jinendra K. Ranka, David L. Spears, Richard M. Osgood, III
  • Patent number: 6452206
    Abstract: A superlattice structure for thermoelectric power generation includes m monolayers of a first barrier material alternating with n monolayers of a second quantum well material with a pair of monolayers defining a superlattice period and each of the materials having a relatively smooth interface therebetween. Each of the quantum well layers have a thickness which is less than the thickness of the barrier layer by an amount which causes substantial confinement of conduction carriers to the quantum well layer and the alternating layers provide a superlattice structure having a figure of merit which increases with increasing temperature.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: September 17, 2002
    Assignee: Massachusetts Institute of Technology
    Inventors: Theodore C. Harman, Mildred S. Dresselhaus, David L. Spears, Michael P. Walsh, Stephen B. Cronin, Xiangzhong Sun, Takaaki Koga
  • Patent number: 5455421
    Abstract: A photodetector for detecting optical irradiation at a predetermined wavelength is provided with an integral, resonant optical cavity by forming a plurality of layers of material on a metallic reflector backing, the total optical thickness of those layers being an odd multiple of one-quarter of the predetermined wavelength. One of those layers is an active (i.e. optically-absorptive) semiconductor material. When the materials are deposited, that absorbing layer is formed at a level in the cavity including a region of peak optical field. As a result of the enhanced absorption provided by the resonant structure, the active layer may be very thin (i.e., less than one-tenth of a wavelength thick), yielding many beneficial results.
    Type: Grant
    Filed: August 13, 1985
    Date of Patent: October 3, 1995
    Assignee: Massachusetts Institute of Technology
    Inventor: David L. Spears