Patents by Inventor Hans J. Keller

Hans J. Keller 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: 5007432
    Abstract: A medical diagnostic method and apparatus employs differential radiation detection apparatus for remotely detecting temperature differentials between a plurlity of areas on the surface of an object having a plurality of lenses which each focus a beam of radiation from a corresponding area of the body onto a radiation detector in such a way that not more than one field of view reaches the detector at any time.
    Type: Grant
    Filed: July 10, 1989
    Date of Patent: April 16, 1991
    Assignee: Eltec Instruments, Inc.
    Inventors: Hans J. Keller, Walter A. Kuster
  • Patent number: 5006712
    Abstract: A radiation detector comprising a first pair of flat reflective surfces parallel to one another and connected by a second pair of flat rectangular reflective surfaces converging toward one another so as to form a reflective chamber having a relatively wide opening for the entrance of radiation and a relatively narrow opening defining a region for receiving radiaiton, there being a radiation sensor positioned in the receiving region for detecting fluctuations in levels of radiation received from a plurality of detection zones.
    Type: Grant
    Filed: October 8, 1987
    Date of Patent: April 9, 1991
    Assignee: Eltec Instruments, Inc.
    Inventor: Hans J. Keller
  • Patent number: 4930864
    Abstract: An improved optical assembly which provides a panoramic field of view for infrared motion detection. In one form of the invention the optical assembly comprises a spherical section having an inner surface and an outer spherical surface, the outer spherical surface having a radius of curvature centered in a focal region which is suitable for placement of an infrared detector. The inner surface of the spherical section comprises a plurality of circular convex lenses, each lens having an optical axis passing through the focal region. The combination of the outer spherical surface with each circular convex lens forms a biconvex lens having a focal point in the focal region. Radiation received by each biconvex lens from a zone in the field of view is focused in the focal region for sensing by the infrared detector.
    Type: Grant
    Filed: August 2, 1988
    Date of Patent: June 5, 1990
    Assignee: Eltec Instruments, Inc.
    Inventors: Walter Kuster, Hans J. Keller
  • Patent number: 4868390
    Abstract: A pyroelectric sensor circuit arrangement for reducing noise and increasing sensitivity has a main current amplifier with a high feedback resistor connected to receive input from an electrode of a pyroelectric element, and includes a compensation amplifier in a unity gain amplifier configuration connected to a common power source with the main amplifier. The compensation amplifier is connected to discharge transients from the pyroelectric element when electrode voltage exceeds the positive voltage or goes below the negative voltage of the power source. A pair of anti-parallel diode or similar component is connected between the main amplifier input and the compensation amplifier output.
    Type: Grant
    Filed: February 16, 1988
    Date of Patent: September 19, 1989
    Assignee: ELTEC Instruments, Inc.
    Inventors: Hans J. Keller, Fredrick Villers