Patents by Inventor Richard R. Pettijohn

Richard R. Pettijohn 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: 4299904
    Abstract: A method of enhancing photographic images of low optical density is disclosed which includes use of a luminescent system, the components of which system include, at least, photoluminescent material and a source of photons for exciting the same to luminescence. A photoluminescent replica of the low optical density photographic image is produced which replica is exposed to photons required for luminescence of the photoluminescent image replica which luminescence is recorded, or photographed, for an amount of time necessary to achieve enhancement of the photographic film image. The image enhancement method may be used for the enhancement of photographic images produced by photographic processes including, for example, those which involve the use of different radiant energy sensitive material such as silver halide as used in `conventional` photography, photoconductive material as used in electrophotography, organic compounds as used in diazo photographic processes, and the like.
    Type: Grant
    Filed: November 28, 1978
    Date of Patent: November 10, 1981
    Assignee: SRI International
    Inventors: Richard R. Pettijohn, Charles Leung, Ronald G. Manning, Zoila Reyes, Malcolm Thackray
  • Patent number: 4147564
    Abstract: A method of forming a microscopically texturized surface on a crystalline semiconductor material is disclosed which method includes the use of a radioactive source for uniformly irradiating the surface. The radioactive source includes a plane surface having a uniform distribution of radioactive material thereon In one arrangement the radioactive source surface area is at least the size of the polished crystalline semiconductor surface to be texturized, and the radioactive source is positioned closely adjacent the polished surface for a predetermined time period for uniform irradiation of the same. If desired, the radioactive source and crystalline surface may be relatively movable during irradiation of the surface, in which case the source may be in the form of an elongated strip of sufficient length to extend beyond opposite edges of the polished surface area to be texturized.
    Type: Grant
    Filed: November 18, 1977
    Date of Patent: April 3, 1979
    Assignee: SRI International
    Inventors: Thomas J. Magee, Richard R. Pettijohn, Shelley A. Stewart, Malcolm Thackray