Iit Research Institute

Itt Research Institute

Craig S Bartholomew

Edward M Kozak

Howard T Betz

Richard J Harris

Narayan P Murarka

Kent J Kogler

Retroreflective glass or plastic beads have fluorescent properties when irradiated with ultraviolet light and are emplaced in signs in patterns indicative of alphanumeric characters, or embedded in a hot melt comprising road stripes or embedded in the road asphalt or aggregate during construction of the road, to provide effectively bright and clear indications of signs or the extent and direction of the road. The glass beads comprise spherodized soda lime, borosilicate, phosphosilicate or aluminosilicate glasses with low levels of rare-earth dopants mixed therein, such as compounds containing one of the rare earths, or lanthanides. The plastic beads may have fluorescent materials mixed therein, typically organic pigments or dyes based on coumarin and rhodamine or the like.

Spherodized fluorescent beads for improved roadway pavement marker

A heterodyning interferometric monitoring apparatus for simultaneously measuring in situ and in real time the optical and physical thicknesses of a sample during a deposition process. A linearly polarized monochromatic light beam is passed through a frequency shifter which produces therefrom a dichromatic light beam having two orthogonally linearly polarized components at respective different frequencies. The dichromatic beam is applied to a modified Twyman-Greene interferometer, from which two heterodyne light beams emerge. The first of the two light beams is a combination of light at the first frequency reflected from the sample and light at the second frequency reflected from a reference plate, from which the physical thickness of the sample can be determined using a heterodyne signal detector. The second light beam is a combination of light at the first frequency passed through the sample and light at the second frequency passed through the reference plate, from which the optical thickness of the sample can be determined using another heterodyne signal detector.

Rugate optical filter systems

A method for fabricating graded refractive index (rugate, optical filters as well as complex rugate filters having prespecified refractive index verses thickness profiles is disclosed. A plurality of at least two different compatable thin film deposition source components of different refractive index, which are stoichiometrically combinable in variable proportion, such as silicon nitride and silicon oxide, or zinc sulfide and zinc selenide, are used to form a thin film material with a refractive index which varies as a function of the proportions of the components. Each source component is separately laser flash evaporated and codeposited on a substrate to form a coating while monitoring the physical and optical thicknesses of the coating, to allow adjustment of the respective laser flash evaporation rates of the source components.

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Glen Ellyn, IL, United States of America

Craig S Bartholomew