Browsing by Author "Leonhardt, Klaus"
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Item Open Access Determination of average roughness and profile autocorrelation width of metallic surfaces with a white light sensor(1984) Leonhardt, Klaus; Kaufmann, Ekkehart; Tiziani, Hans J.A new procedure to determine simultaneously a horizontal descriptor of the surface - the autocorrelation width - and the most important vertical descriptor - the root-mean-square roughness - is presented. It is based on the inversion of an analytic contrast formula. After a short introduction to white light random phase contrast measurement we describe the elimination process and show first experimental verifications.Item Open Access Holography and speckle techniques for real time displacement deformation and vibration analysis(1980) Tiziani, Hans J.; Klenk, Jürgen; Leonhardt, KlausHolographic interferometry and speckle application are powerful techniques for deformation, displacement and vibration analysis especially when they can be applied in real time. Bismuth Silicon Oxide crystals Bi12SiO20 (BSO) were used for real-time deformation, displacement and vibration analysis using holography and "speckle photography". After a short introduction of holographic interferometry for deformation measurement using BSO crystals, speckle applications for deformation, displacement and vibration analysis in real time will be discussed.Item Open Access Micro shape and rough surface analysis by fringe projection(1993) Leonhardt, Klaus; Droste, Ulrich; Schön, Stefan; Voland, Christoph; Tiziani, Hans J.A new microscopic fringe projection system is described. Projection of the grating and imaging of the fringes is accomplished by the same objective. The spectrum of the binary grating is spatially filtered and projected into the aperture with a lateral shift. This leads to telecentric projection and imaging under oblique incidence. Topographies of specularely as well as diffusely reflecting surfaces can be obtained. The measurement of rough, technical surfaces is demonstrated.Item Open Access Micro-ellipso-height-profilometry(1991) Leonhardt, Klaus; Jordan, Hans-Joachim; Tiziani, Hans J.A new instrumental concept for surface measurement is described. In Micro-Ellipso-Height-Profilometry three independent profiles h(x), ψ(x) and Δ(x) of a surface are measured from one diffraction limited scanning spot. The basic equations for the extraction of these three quantities are derived and first results are discussed.Item Open Access Microshape and rough-surface analysis by fringe projection(1994) Leonhardt, Klaus; Droste, Ulrich; Tiziani, Hans J.A fringe-projection system for microscopic applications, fringe-projecting microscopy, is developed and analyzed. Projection of the grating and imaging of the fringe system, modulated by the surface, are accomplished by the same high-aperture objective. The spectrum of the grating is spatially filtered and projected into the aperture with a lateral shift, which leads to a telecentric projection under oblique incidence and telecentric imaging. Topographies of specularly as well as diffusely reflecting surfaces can be obtained. The measurement of highly rough surfaces is described together with preprocessing steps. The resulting intensity distribution of the fringes is analyzed. Formulas for vertical and lateral resolution, measuring range, and dynamic range, based on noise considerations, are presented and verified by topographies of technical surfaces.Item Open Access Mikro-Profilometrie zur Bestimmung der Topographie und Rauheit technischer Oberflächen mittels Heterodyn-Laserinterferometrie(1989) Leonhardt, Klaus; Rippert, Karl-Heinz; Tiziani, Hans J.Ein Heterodyn-Profilometer zur Messung der Rauheit polierter und feingeschliffener Oberflächen und zur Formmessung wird beschrieben. Die Vertikal- oder Höhenauflösung liegt bei 0,5 nm, der Meßbereich für Formmessungen an glatten Oberflächen bei 40 pm bei einer maximalen Abtastlänge von 300 mm. Die Lateralauflösung kann je nach Aperturausleuchtung bis zu 0,5 pm eingestellt werden. Anwendungen und Grenzen werden gezeigt, Formeln zur Lateralauflösung und zur Erfassung von Phasensprüngen sowie Profilhöhen-Übertragungsfunktionen werden diskutiert.Item Open Access Optical methods of measuring rough surfaces(1989) Leonhardt, Klaus; Rippert, Karl-Heinz; Tiziani, Hans J.The statistical parameters of surfaces to be measured for industrial applications vary over several orders of magnitude. Surfaces with large slopes or edges are particularly difficult to be recorded. Some measuring methods developed in our laboratory are compared and the range of applications are discussed. For polished and fine ground glass and metal surfaces a heterodyne profilometer with a vertical resolution of 0.5 nm, lateral resolution of 0.6 μm, and large scanning length is discussed. The interferometer can be changed from single- to double-pass operation by rotation of a quarter-wave-plate. For rougher surfaces a profilometer of the photometric-balance type with resolution Rq < 4 nm and dynamic range of 20 μm and an interference microscope with automated fringe evaluation is described. An integral white light roughness sensor covers the roughness range 0.04μm to 10μm and measures independently mean roughness and autocorrelation width.Item Open Access Optische Mikroprofilometrie und Rauheitsmessung(1987) Leonhardt, Klaus; Rippert, Karl-Heinz; Tiziani, Hans J.Es werden moderne optische Verfahren zur berührungslosen Oberflächentopographie und Rauheitsmessung beschrieben und ihre Leistungsfähigkeit anhand neuerer Messungen und Analysen diskutiert. Dabei werden zwei Verfahren der Mikroprofilometrie, eine schnelle 3-D-Darstellung der Oberflächentopographie mit automatischer Interferenzstreifenauswertung, kohärente Streuverfahren und ein integrales Weißlicht-Kohärenzverfahren ausführlich behandelt. Außerdem werden eine neue Doppelpaß-Strahlenführung und Ausdrücke für die Erfassung der Lateralauflösung in Abhängigkeit von der numerischen Apertur und dem Ausleuchtungsverhältnis angegeben.Item Open Access Real-time displacement and tilt analysis by a speckle technique using Bi12SiO20-crystals(1980) Tiziani, Hans J.; Leonhardt, Klaus; Klenk, JürgenStorage of speckle pattern in real time by means of Bi12SiO20-crystals will be reported. Applying the double exposure technique, deformations, displacements as well as tilts can be analysed. The novel speckle technique displays the Young-interference fringes in quasi real time.Item Open Access Removing ambiguities in surface roughness measurement(1982) Leonhardt, Klaus; Tiziani, Hans J.A new method is presented for the measurement of surface roughness in the range Ra ≈ 0·05-10 μm. The data from a strongly defocused low-contrast image of a rough surface is scanned, and the contrast value, C = σI/<I>, is processed. A relatively low degree of spatial and temporal coherence, combined with a relatively high-image aperture and a detector aperture (which is much wider than the nominal speckle width of the corresponding highly coherent speckle pattern) led to important instrumental advantages, e.g., illumination by an incandescent lamp, simple photodetectors, short measuring times and simple, inexpensive, compact construction. The superposition of uniform intensity to the phase contrast structure, which leads to a strictly monotonic dependence of the measured contrast over a very wide range of the roughness values Ra is of great importance. Practical measurements of metallic surface standards are reported and discussed, and the theoretical aspects of the superposition of uniform intensity are pointed out with the help of a new analytic expression for the stochastic contrast.Item Open Access Temperature induced deformations in BSO crystals due to photoconductivity(1983) Leonhardt, Klaus; Tiziani, Hans J.Deformationen durch Wärmedehnungen können in Bi12Si020 (BSO)-Kristallen, die in der optischen Meßtechnik angewendet werden, zu Störungen in den Wellenfronten und zur Verringerung des Beugungswirkungsgrades führen. Die Wärmedehnungen entstehen durch den Photostrom des an den Kristall angelegten äußeren Feldes. Es werden Dickenänderungen und zugehörige Temperaturänderungen an der Kristalloberfläche als Funktion der angelegten Spannung und der elektrischen Leistung gemessen und Intensitätsmuster durch den spannungsoptischen Effekt gezeigt. Einige Konsequenzen für den praktischen Einsatz der Kristalle in Meßanwendungen werden besprochen.Item Open Access Verfahren zur optischen Rauheitsmessung und Mikroprofilometrie(1985) Leonhardt, Klaus; Rippert, Karl-Heinz; Tiziani, Hans J.In diesem Beitrag werden wegen der Kürze der Darstellung nur einige der bekannten Verfahren behandelt. Zwei Verfahren der Mikroprofilometrie, die im Institut für Technische Optik Stuttgart zur Zeit bearbeitet werden und ein Verfahren der integralen Rauheitsmessung, das in unserem Institut entwickelt wurde, werden ausführlicher beschrieben.