Patents by Inventor Keith N. Prettyjohns

Keith N. Prettyjohns 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: 5818571
    Abstract: Apparatus for determining the luminous intensity distribution of an automotive head light employs a curved mirror and a curved screen. A solid state camera is used to obtain a pattern of the head light output from the screen. The system requires a relatively small black box into which the head light output is directed. A beam splitter may be employed to relax the constraints on the positioning of the various components within the box. The setting of the test lamp to first and to second preset lateral angular positions at each of which a pattern is captured and the combining of the two patterns permits the use of components which are practical. The use of a linear CCD array permits economies to be obtained by rotating the test lamp or by scanning the linear array over a sequence of angular positions and by constructing a composite pattern from the patterns so generated. In an alternative embodiment, no beam splitter is used.
    Type: Grant
    Filed: April 14, 1997
    Date of Patent: October 6, 1998
    Assignee: Photometrics, Ltd.
    Inventors: Keith N. Prettyjohns, Stephen L. Marcus, Stephen F. Sagan
  • Patent number: 5729336
    Abstract: Apparatus for determining the luminous intensity distribution of an automotive head light employs a curved mirror and a curved screen. A solid state camera is used to obtain a pattern of the head light output from the screen. The system requires a relatively small black box into which the head light output is directed. A beam splitter may be employed to relax the constraints on the positioning of the various components within the box. The setting of the test lamp to first and to second preset lateral angular positions at each of which a pattern is captured and the combining of the two patterns permits the use of components which are practical. The use of a linear CCD array permits economies to be obtained by rotating the test lamp or the linear array over a sequence of angular positions and by constructing a composite pattern from the patterns so generated.
    Type: Grant
    Filed: May 6, 1996
    Date of Patent: March 17, 1998
    Assignee: Photometrics, Ltd
    Inventors: Keith N. Prettyjohns, Stephen L. Marcus, Kevin J. Garcia
  • Patent number: 4639139
    Abstract: An optical profiler includes a two-beam interferometer. An interference pattern produced thereby is focused onto an array of photocells. Phase shift in a reference beam of the interferometer is produced by accelerating a piezoelectric transducer supporting the interferometer mirror to a constant velocity. The velocity is maintained constant for at least 360.degree. of phase shift, during which four integrated buckets are obtained from each photocell. The outputs of the photodetector array are continuously integrated and effectively read out every 90.degree. of phase shift of the reference beam by a computer that computes a first value of phase corresponding to each photocell output from the first, second, and third integrated buckets produced by that photocell and a second phase value from the second, third, and fourth integrated bucket values obtained from that photocell.
    Type: Grant
    Filed: September 27, 1985
    Date of Patent: January 27, 1987
    Assignee: Wyko Corporation
    Inventors: James C. Wyant, Keith N. Prettyjohns