Universitãt Stuttgart

Sirona Dental Systems Gmbh

Klaus Körner

Wolfgang Osten

Alois Herkommer

Christof Pruss

Aiko Ruprecht

Simon Thiele

Christian Kohler

Marc Gronle

Daniel Claus

Reinhard Berger

Giancarlo Pedrini

Evangelos Papastathopoulus

Tobias Boettcher

Wolfram Lyda

Ulrich Droste

Rainer Gadow

Tobias Wiesendanger

Alois M Herkommer

Fourier Transformation Spectrometer, FT Spectrometer, comprising: Michelson-Type Interferometer () comprising: at least one beam splitter unit designed to split an incident light beam (EB) of a spatially expanded object into a first partial beam (TB) and a second partial beam (TB); and for at least partially overlaying the first partial beam (TB) and the second partial beam (TB) with a lateral shear (s); a first beam deflection unit designed to deflect the first partial beam (TB) at least once; a second beam deflection unit designed to deflect the second partial beam (TB) at least once; wherein at least one among the first beam deflection unit and the second beam deflection unit represents a (2n+1) periscope group with (2n+1) mirror surfaces, and all (2n+1) mirror surfaces are arranged vertically in relation to a common reference plane, in order to respectively deflect the first partial beam (TB) and/or the second partial beam (TB) (2n+1) times, and wherein the (2n+1)-fold deflection generates the lateral shear (s) between the first partial beam (TB) and the second partial beam (TB), and wherein n is a natural number &#x2265;1.

Method and shear-invariant Michelson-type interferometer for single shot imaging FT-spectroscopy

Fourier Transformation Spectrometer, FT Spectrometer, comprising: A double beam interferometer, comprising: At least one beam splitter unit () for splitting an incident light beam (EB) of a spatially expanded object into a first partial beam (TB) and a second partial beam (TB); at least a first beam deflection unit () designed to deflect the first partial beam (TB) at least a first and a second time, wherein the second beam deflection unit () is designed to also deflect the second partial beam (TB) at least at first and a second time; or the double beam interferometer comprises a second beam deflection unit () designed to deflect the second partial beam (TB) at least a first and a second time, wherein the beam deflection unit is also designed to at least partially spatially overlay the first partial beam (TB) and the second partial beam (TB), and the respectively first and second deflection of the first partial beam (TB) and of the second partial beam (TB) generates a lateral shear (s); at least a first field of view discriminator unit (BFD) arranged such that the first partial beam (TB) is spatially selected after the splitting and prior to the second deflection; at least a second field of view discriminator unit (BFD) arranged such that the second partial beam (TB) is spatially selected after the splitting and prior to the second deflection.

Method and Fourier Transformation spectrometer with double beam interferometer for Single Shot Imaging Fourier Spectroscopy

The present invention relates to a method and an assembly for chromatic confocal spectral interferometery, in particular also for spectral domain OCT (SD-OCT) using multi-spectral light. A multiple (e.g. two, three, four, etc.) axial splitting of foci in the interferometric object arm is performed using a multifocal (e.g. bifocal, trifocal, quattro-focal, etc.) optical component, forming thereby at least two, three or even several groups of chromatically split foci in the depth direction. The multifocal optical component is made of a diffractive optical element () and a Schwarzschild objective (). At least two, three, four or even more differently colored foci of different groups of foci coincide in at least one confocal point in the object space of the setup. Thus, at least two, three or even more spectral wavelets are formed in the case of optical scanning of an object measurement point and spectral detection in the wavenumber domain, which wavelets are at least slightly spectrally separated from each other. This results in a significant increase in the optical primary data in the wavenumber domain and reduces the trade-off of the chromatic confocal spectral interferometry between axial measurement range and depth resolution. From the detected data, it is possible to calculate tan (alpha) as the quotient of the absolute phase shift delta_phi and the associated wavenumber difference delta_k, the Fourier transform over the spectral data, in order to respectively determine the optical path difference.

Method and assembly for chromatic confocal spectral interferometry or spectral domain oct

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

Proposed are an arrangement and a method for depth-scanning strip triangulation with internal or external depth scan, particularly also for the 3D shape measurement in microscopy and mesoscopy. The robustness of the measurement with wavelet signal generation from an image stack is to be increased. The occurrence of the known and very undesirable 2Pi phase jumps in the phase map is to be avoided as much as possible. To do this, with a measurement instead of a wavelet at least two wavelets with contrast envelope are generated. This is done by a concurrent&#x2014;then preferably with spectral separation&#x2014;or by a sequential projection of two strip images with different triangulation wavelengths on the measured object.

Method and arrangement for robust, depth-scanning/focusing strip triangulation by means of a plurality of wavelets

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 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

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.

Growing community of inventors

Berlin, Germany

Klaus Körner