Universitãt Stuttgart

Carl Mahr Holding Gmbh

Sirona Dental Systems Gmbh

Baden-Wurttemberg Stiftung Ggmbh

Wolfgang Osten

Christof Pruss

Klaus Koerner

Klaus Körner

Aiko Ruprecht

Daniel Claus

Christian Kohler

Goran Baer

Giancarlo Pedrini

Reinhard Berger

Alois Herkommer

David Hopp

Peter Lehmann

Marc Gronle

Jürgen Mohr

Tobias Boettcher

Wolfram Lyda

Ulrich Droste

Tobias Wiesendanger

Evangelos Papastathopoulus

Peter Lücke

Carlos Javier Moran-Iglesias

Sven Schönfelder

Christof PRUß

Rainer Gadow

Arnulf Roeseler

Klaus KÖRNER

Arnulf Röseler

The present invention relates to an arrangement and a method for single-shot interferometry which can be used for detecting distance, profile, shape, undulation, roughness or the optical path length in or on optically rough or smooth objects or else for optical coherence tomography (OCT). The arrangement comprises a light source, an interferometer, in which an end reflector is arranged in the reference beam path, and also a detector for detecting an interferogram. In the reference beam path of the interferometer, the end reflector can be embodied with three plane reflecting surfaces as a prism mirror or air mirror assembly in order to generate between reference and object beams a lateral shear of magnitude delta_q for obtaining a spatial interferogram. The embodiment of said assembly with regard to the angles and the arrangement of the reflecting surfaces makes possible a large aperture angle for a high numerical aperture. In the method, in the reference beam path it is possible to carry out a reduction of the aperture angle of the reference beam using beam-limiting means in order to achieve an optimum adaptation to the geometrically given aperture angle of the end reflector in the reference beam path, which is designed to be smaller than the aperture angle in the object beam path. The end reflector in the reference beam path can also be used as part of a second interferometer for high-resolution measurement of the displacement of the arrangement for single-shot interferometry, wherein said displacement serves for focusing. The end reflector is embodied as a triple reflection arrangement (e.g. a prism arrangement) having three reflecting surfaces. The triple reflection arrangement can have an M- or W-beam path, a non-intersecting zigzag beam path or an intersecting (zigzag) beam path.

Arrangement and method for robust single-shot interferometry

An interferometer for areally measuring an optically smooth surface is presented, including means for illuminating a surface region with a plurality of discrete object waves from different directions and comprising means which, on a detector, superimpose object waves reflected at the surface onto a reference wave that is coherent with a plurality of object waves in order to form an interferogram. The interferometer is distinguished by virtue of it being configured to illuminate the surface with a plurality of object waves at the same time and produce the reference wave by way of a Fizeau beam splitter plate or a Fizeau objective, and by virtue of the interferometer including an interferometer stop that is arranged in the beam path upstream of the detector, and imaging optics, wherein the interferometer stop is situated within, or slightly outside of, the Fourier plane of the imaging optics and said interferometer stop filters the object waves reflected by the surface.

Interferometer using tilted object waves and comprising a Fizeau interferometer objective

The present invention relates to a method and an apparatus for establishing residual stresses in objects, in particular in coated objects, and to a method and an apparatus for coating objects. The method comprises: impinging a surface () of the object () with laser light and generating a hole or a pattern of holes and/or locally heated points in the object (); establishing the surface deformations by an optical deforming measuring method after the object () is impinged by laser light; establishing the residual stresses present in the object () from the measured surface deformations, wherein the generation of the hole pattern is carried out by an optical scanning apparatus which comprises an optical deflection and/or modulation arrangement for controllable deflection and/or modulation of the laser light, and/or a focusing arrangement for controllable focusing of the laser light.

Optical method and arrangement for measuring residual stresses, in particular in coated objects

The invention relates to a method for calibrating a measuring device, comprising the following steps: moving, with finite accuracy and thus with positioning error, to various points that lie in a testing volume of the measuring device and that can be characterized by spatial and/or angular coordinates, generating measurement signals at the respective points, and determining parameters of a computing model of the measuring device from the measurement signals and the spatial and/or angular coordinates. The method is characterized in that a coordinate system to which the coordinates of the points of the testing volume relate is defined from points moved to with error, by associating predetermined coordinate values with exactly six coordinates of three points.

Method for calibrating a measuring device

The invention relates to methods and to devices for generating multispectral illuminating light having an addressable spectrum, for adaptive multispectral imaging and for capturing structural and/or topographical information of an object or of the distance to an object. The illuminating device comprises a multispectral light source and a modulator for temporal modulation of the individual spectral components of the multispectral light source having modulation frequencies. The multispectral light source comprises at least one light source having a continuous, quasi-continuous, or frequency comb spectrum and wavelength-dispersive means, or an assembly or array of monochromatic or quasi-monochromatic light sources having emission wavelengths or emission wavelength bands which are different from one another in each case. The modulator comprises at least one electrically controllable three-dimensional light modulator, or a plurality of electronic control modules assigned to the individual monochromatic or quasi-monochromatic light sources.

Method and device for generating multispectral or hyperspectral light, for hyperspectral imaging and/or for distance measurement and/or 2D or 3D profile measurement of an object by means of spectrometry

Disclosed herein is a measuring probe and an arrangement for measuring spectral absorption, preferably in the infrared. Furthermore, the invention relates to a method for spectroscopically measuring absorption. The measuring probe may comprise a cutting apparatus configured to cut a slice or respectively flap off of a sample to be measured; a measuring gap configured to accommodate the sample slice; an optical window element for coupling measuring light into, or respectively out of the measuring gap; and an end reflector designed and arranged to reflect the measuring light propagated through the measuring gap back into the measuring gap. The arrangement for measuring spectral absorption may comprise the measuring probe, a light source and an apparatus for the spectral analysis of the measuring light coupled out of the measuring gap.

Method and apparatus for optical absorption measurements

Disclosed are methods and an assembly for robust one-shot interferometry, in particular for optical coherence tomography according to the spatial domain approach (SD-OCT) and/or according to the light-field approach. In one embodiment, the method and the assembly may be used for measurements on material and living tissue, for distance measurement, for 2D or 3D measurement with a finely structured light source imaged onto the object in a diffraction-limited way, or with spots thereof. The assembly may comprise an interferometer having object and reference arms and a detector for electromagnetic radiation. In other embodiments, during a detection process, a plurality of spatial interferograms may be formed by making an inclined and/or curved reference wavefront interfere with an object wavefront for each measurement point. The resulting spatial interferograms may be detected in a single detector frame and may be further evaluated via a computer program.

Robust one-shot interferometer

Disclosed herein is an apparatus for spectroscopic ellipsometry, preferably for infrared spectroscopic ellipsometry, and a method for spectroscopic ellipsometry employing the apparatus. In some embodiments, the apparatus may comprise a light source (), a detector (), a polarizer (), an analyzer (), and a measuring probe (). In one embodiment, the measuring probe may comprise an ATR prism () having at least one first surface having at least one measuring portion (M) configured to be brought in optical contact with a measured object (), and at least one second surface having at least one reflective portion (RX).

Apparatus and a method for spectroscopic ellipsometry, in particular infrared spectroscopic ellipsometry

The invention relates to a method and arrangement for short coherence holography for distance measurement, for profile detection and/or for 3D detection of one or more object elements and/or object areas and/or objects or for readout of holographic volume memories with a holographic interferometer and with at least one short coherence light source. For each optically detected object element in the hologram the holographic interferometer has an optical path difference clearly unequal to zero. At least one spectrally integrally detecting, rastered detector is arranged. The short coherence light source with frequency comb is designed with the optical delay length Y. Detected holograms are digitally reconstructed. Relative distances of object elements are digitally calculated from the hologram reconstructions, so that a 3D point cloud of object elements and/or object areas and/or objects is produced. Data can be read out optically in parallelized form from holographic volume memories or three-dimensionally structured signatures.

Method and arrangement for short coherence holography

The invention relates to an improved encoding disk for an optical rotation angle sensor or a rotary encoder, an optical rotation sensor or rotary encoder comprising an improved encoding disk, and a method for optically correcting or compensating for an angle measuring error of a rotary encoder, in particular an angle measuring error which is contingent on a displacement or decentralization of the encoding disk. The encoding disk () comprises at least one measuring track () and at least one compensating track (), wherein the measuring track () is in a first radial region of the encoding disk (); and the compensating track () is centered with regard to the measuring track () on a second radial region of the encoding disk () so that the center of the measuring track () coincides with the center of the compensating track (). The compensating track () is preferably designed such that at least one part of the light incident on a region of the compensating track is deflected by the compensating track () radially in the direction of the axis through the common center of the compensating track () and the measuring track (). The direction of the readout light which is deflected by the compensating track preferably intersects the axis through the common center of the compensating track and the measuring track, wherein the distance between the compensating track and said intersection corresponds to the length of the light path between the compensating track and the measuring track. The readout light can be coherent or incoherent. The radius of the compensating track can be less than, greater than, or equal to the radius of the measuring track. The compensating track () preferably has a diffractive structure.

Device and method for optically compensating for the measuring track decentralization in rotation angle sensors

An arrangement and a method are provided for robust interferometry for detecting distance, depth, profile, form, undulation, flatness deviation and/or roughness or the optical path length in or on technical or biological objects, including in layered form, or else for optical coherence tomography (OCT), with a source of electromagnetic radiation and with an interferometer, in particular also in the form of an interference microscope, having an object beam path and having a reference beam path, in which an end reflector is arranged, and a line-scan detector for detecting electromagnetic radiation in the form of at least one spatial interferogram.

Method and arrangement for robust interferometry for detecting a feature of an object

A method and an arrangement are provided for scalable confocal interferometry for distance measurement, for 3-D detection of an object, for Optical Coherence Tomography (OCT) tomography with an object imaging interferometer and at least one light source. The interferometer has an optical path difference not equal to zero at each optically detected object element. Thus, the maxima of a sinusoidal frequency wavelet, associated with each detected object element, each have a frequency difference &#x394;f_Object. At least one spectrally integrally detecting, rastered detector is arranged to record the object. The light source preferably has a frequency comb, and the frequency comb differences &#x394;f_Source are changed in a predefined manner over time in a scan during measuring. In the process, the frequency differences &#x394;f_Source are made equal to the frequency difference &#x394;f_Object or equal to an integer multiple of the frequency differences &#x394;f_Object at least once for each object element.

Method and apparatus for interferometry

An interferometric confocal method and assembly for terabyte volume optical data memories couples two-beam spectral interferometry to chromatic confocal technology and permits a longitudinal splitting of foci in the memory volume, with the foci having limited diffraction. A spectrometer is located downstream of the interferometer with confocal discrimination in the beam path. A diffractive optical zone lens (DOZE) with a usage of the first diffraction order is introduced into the interferometric beam path to achieve longitudinal chromatic splitting. The interferometer can be a fiber-coupled interferometer with a retroreflector in the fiber-coupled reference arm and with wavelength-dependent optical path difference modification by dispersion or diffraction. The optical path difference in the interferometer is set so that easily detectable wavelets are formed from detectable interferograms by spectral analysis.

Method and assembly for confocal, chromatic, interferometric and spectroscopic scanning of optical, multi-layer data memories

A chromatic confocal technique and apparatus for the rapid three-dimensional measurement of an object shape, particularly of a tooth in a patient's jaw, using an array of polychromatic point light sources, a planar detector matrix, a beam splitter for lateral spectral separation, and an objective for illuminating and recording the object. Spectral defined reference light bundles are generated, injected into the detection beam path via a reference beam path and, following spectral splitting, are focused on the detector matrix as reference image points, wherein laterally shifted sub-matrices are numerically defined on the detector matrix for spectral analysis of the object light, which sub-matrices are implemented as spectral cells for three-dimensional measurement of the shape of the object.

Method and arrangement for a rapid and robust chromatic confocal 3D measurement technique

A measuring head () according to the invention comprises the combination of a zone lens (), which is preferably a diffractive lens, with a hemispherical lens () or a GRIN lens (). This represents a concept capable of miniaturization, resulting in very slender measuring heads () having a high numeric aperture and, accordingly, leads to the best resolution capacity. Such measuring heads are insensitive to angular errors as concerns the orientation of the measuring head to the surface to be measured or to an oblique positioning of the surface relative to the optical axis of the measuring head.

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Stuttgart, Germany

Wolfgang Osten