Sri International

Malcolm Thackray

Ivor Brodie

Richard R Pettijohn

Thomas J Magee

Zoila Reyes

Shelley A Stewart

Charles Leung

Ronald G Manning

Method and apparatus for intensification and reflective read-out of underexposed films, radiographs, and the like are shown which include means for converting a metallic silver particle image to a highly reflective image. The film containing the highly reflective image is placed in a black-walled cavity which may contain a particle-free liquid, such as water. The image is raster scanned by a laser beam, and light reflected from the image is detected by a photomultiplier. The photomultiplier output is digitized and the digitized signal is stored for subsequent computer enhancement and display.

Method for intensification and reflective read-out of underexposed film,

Radiographic imaging method and apparatus are disclosed which include a gas gap formed between closely spaced dielectric and photoconductor surfaces, across which gap a uniform strength electric field is applied. Counting gas is supplied to the gas gap, and penetrating radiation, such as X-ray radiation, is directed onto the photoconductor through an object to be examined. Photons absorbed in the photoconductor induce electron-hole pairs resulting in increased localized conductivity thereof and localized intensification of the electric field across the gas gap to a level for production of gas discharge across the gap. Ion amplification by Townsend cascade enhances charge transfer in the gas gap. An apertured platen may be provided against which dielectric imaging paper is held by gas pressure to facilitate formation of the narrow, substantially uniform width, gas gap. A charge image is produced on the dielectric imaging surface which then is developed using conventional xerographic developing techniques.

Semiconductor-gated ionographic method and apparatus

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.

Photographic image enhancement method employing photoluminescence

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. In any case, the large-surface area radioactive source produces substantially uniform distribution of damage tracks in the crystalline surface, which surface then is anisotropically etched by use of a suitable etching solution. The damage tracks provide etching sites along which etching proceeds at a greater rate than in the undamaged area. Generally the surface to be texturized comprises the (100) orientation surface of a crystalline semiconductor material, such as silicon, at which surface etching preferentially proceeds for exposure of the (111) planes which intersect the surface with fourfold symmetry. With this method a controllable size distribution of tetrahedra may be formed over a large surface.

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Menlo Park, CA, United States of America

Malcolm Thackray