34 research outputs found

    The multigraded Nijenhuis-Richardson Algebra, its universal property and application

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    We define two (n+1)(n+1) graded Lie brackets on spaces of multilinear mappings. The first one is able to recognize nn-graded associative algebras and their modules and gives immediately the correct differential for Hochschild cohomology. The second one recognizes nn-graded Lie algebra structures and their modules and gives rise to the notion of Chevalley cohomology

    Technological investigation of colour filters and microlenses for the monolithic integration in CMOS-photodetector arrays

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    In this thesis two methods for the manufacturing of optical elements for the monolithic integration in CMOS image sensors are described. Polymeric micro colour filters and refractive micro lenses are presented. The colour filters were made of polyimid thin films with the colours Cyan, Yellow and Magenta. 9 x 9 um^2 filters were deposited on previously planarised CMOS substrates. Optical constants are measured by spectroscopic ellipsometry. The optical constants were used to calculate the colour sensor responses which are in good agreement with the experimental values. Raytracing calculations are used to evaluate the improvement of the responsivity by the use of microlenses. It is shown that the architecture of the pixel layout have to be considered to adapt the lens parameters. For the fabrication of the lenses Polymethyl-Methacrylat (PMMA) was used as a hight transparent material. By the melting of PMMA structures the lenses were obtained. A microlens array was deposited on a glass plate to determine the focal length by the following procedure. By illuminating the microlens array with laser light the focused beam was analysed with a microscope objective. It is estimated that the improvement in responsivity could be as high as 30 % with such a PMMA microlens array
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