Abstract: A device for measuring wafers includes an optical coherence tomograph and a scanning device that scans the surface of the wafer successively at a plurality of measuring points. Two measuring points have a distance dmax of 140 mm?dmax?600 mm. An evaluation unit calculates distance values and/or thickness values from the interference signals provided by the optical coherence tomograph.

Abstract: A processing head for a laser processing device adapted for processing a workpiece using laser radiation has: adjustable focusing optics to focus laser radiation in a focal spot having an adjustable distance from the processing head; an optical coherence tomograph to measure a distance between the processing head and the workpiece by measuring an optical interference between measuring light reflected by the workpiece and measuring light not reflected by the workpiece; a path length modulator that can change, synchronously with and dependent on a change of the focal spot distance from the processing head, an optical path length in an optical path along which measuring light propagates; a scanning device, which deflects the laser radiation in different directions; and a control device, which i) controls a focal length of the focusing optics in such a way that the focal spot is situated at a desired location on the workpiece, ii) receives, from the coherence tomograph, information representing the distance betwe

Abstract: A method for measuring the depth of the vapour cavity during an industrial machining process employs a high-energy beam. An optical measuring beam is directed towards the base of a vapour cavity. An optical coherence tomograph generates interference factors or other raw measurement data from reflections of the measurement beam. An evaluation device generates undisturbed measurement data, wherein raw measurement data that is generated at different times is processed together in the course of a mathematical operation. This operation can be a subtraction or a division. Slowly changing interference factors can thus be eliminated. An end value for the distance to the base of the vapour cavity is calculated from the undisturbed measurement data using a filter. As a result, the depth of the vapour cavity can be determined, in the knowledge of the distance at a part of the surface of the work piece that is not exposed to the high-energy beam.

Abstract: A method for determining parameters for the position and orientation of the cornea of an eye and involves the steps of generating linear structures on the iris and/or sclera of the eye, having a camera capture a first image of the eye including the linear structures, and determining, on the basis of the first image, a distance and an orientation of the linear structures in relation to the camera.

Abstract: A chromatic confocal measuring device for the measurement of distances and/or thicknesses of several locations has a light source that emits polychromatic measuring light through a light exit surface. The light source is a laser pumped luminophore-based light source and has an oblong exit surface. The measuring device further has at least one first confocal aperture through which the measuring light passes and which comprises a plurality of punctiform orifices or at least one slit-shaped orifice. The measuring device also includes imaging optics configured to cause a chromatic focus shift of the measuring light and to image the first confocal aperture in a measurement volume so that different wavelengths are focused at different heights.

Abstract: A measuring device includes a light source that emits light of a plurality of wavelengths, in particular a continuous spectrum, a first confocal diaphragm, through which light from the light source passes, and an optical illuminating/imaging system having a first splitting optical element designed as a prism or grating. The optical illuminating/imaging system, which is designed such that the light enters the first splitting optical element collimated, includes a first lens system having at least one first lens that is spatially separated from the first splitting optical element, the effective focal length of the first lens system being significantly different for different wavelengths, and the optical illuminating/imaging system being designed such that focus points of different wavelengths are formed at different locations along a line segment. The measuring device is configured to measure an object that intersects with the line segment and reflects at least a part of the light.

Abstract: A method for controlled machining of a workpiece includes focusing a laser light beam on a target point of the workpiece to generate a laser focus point. An optical distance measuring device gathers measuring data to determine a distance between the target point and a laser target optics. The workpiece is positioned in relation to the laser focus point based on the distance measuring data gathered. The distance measuring device is a confocal optical distance measuring device having a measuring light source for generating a measuring light and having a variable-focal-length measuring lens system. The focal length of the variable-focal-length measuring lens system is varied over time to gather distance measuring data at different focal length values of the variable-focal-length measuring lens system. A device for controlled machining includes a laser light source, a laser target optics, a distance measuring device, a positioning device, and an evaluation and control unit.

Abstract: The invention relates to a device for optical measurement of a thickness of an intransparent layer on a substrate, comprising first means for optical distance measurement configured to measure a first distance between a first reference plane and a first surface of the intransparent layer, and second means for optical distance measurement configured to measure a second distance between a second reference plane and a second surface of the intransparent layer. The second means measures a third distance between the second reference plane and a surface of the substrate. The thickness of the intransparent layer is computed from the first distance and the second distance. The measurement of the third distance is used to take into account the influence of the optical effect of the substrate on the distance measurement of the second distance. The invention also relates to a method for optical measurement of a thickness of an intransparent layer on a substrate.

Abstract: A measuring device includes a light source that emits light of a plurality of wavelengths, in particular a continuous spectrum, a first confocal diaphragm, through which light from the light source passes, and an optical illuminating/imaging system having a first splitting optical element designed as a prism or grating. The optical illuminating/imaging system, which is designed such that the light enters the first splitting optical element collimated, includes a first lens system having at least one first lens that is spatially separated from the first splitting optical element, the effective focal length of the first lens system being significantly different for different wavelengths, and the optical illuminating/imaging system being designed such that focus points of different wavelengths are formed at different locations along a line segment. The measuring device is configured to measure an object that intersects with the line segment and reflects at least a part of the light.

Abstract: The invention relates to a machining head for a laser machining device, which is equipped for machining a workpiece (24) using laser radiation (30). The laser machining head comprises an adjustable focusing optical unit (34), which focuses the laser radiation (30) in a focal spot (22). The distance between the focal spot (22) and a machining head can be modified by modifying the focal length of the focusing optical unit (34). A scanning apparatus (44) deflects the laser radiation (30) in different directions. An optical coherence tomography device (48) measures a distance between the treatment head and the workpiece (24). Here, measuring light (52), which was generated by a measuring light source (50) and reflected by the workpiece (24), interferes in the coherence tomography device (48) with measuring light, which traveled an optical path length in a reference arm (60).

Abstract: A chromatic confocal distance sensor has a housing in which a polychromatic light source, imaging optics having a longitudinal chromatic aberration, a spectrometer and a planar beam splitter surface are arranged. These lie in the light path of the measurement light between the light source and the imaging optics and between the imaging optics and the spectrometer. A first diaphragm is arranged in the light path between the light source and the beam splitter surface, and a second diaphragm is arranged in the light path between the beam splitter surface and the spectrometer. The diaphragms are arranged mirror-symmetrically with respect to the beam splitter surface. The measurement light propagates as a free beam inside the housing. The beam splitter surface, the first diaphragm and the second diaphragm are fastened together on a carrier which has an isotropic thermal expansion coefficient. This way, temperature changes cannot significantly affect the measurement accuracy.

Abstract: A device for measuring a distance to an object comprises a beam splitter for splitting broadband coherent light emitted by a light source in measuring light which is guided through an object arm to the object to be measured and in reference light which is guided to a reference arm. The object arm includes a focusing optics with a focus movable along an optical axis of the object arm. The focusing optics comprises a movable optical element and is configured such that a movement of the movable optical element along the optical axis causes a higher movement of the focus of the focusing optics along the optical axis. The movable optical element of the focusing optics is coupled to the reference arm such that the optical path length of the reference arm can be tracked synchronously with and dependent on the movement of the focus of the focusing optics.

Abstract: A chromatic confocal measuring device includes a light source, which emits light of a plurality of wavelengths, and a first beam splitter, via which the light from the light source into an imaging optical unit having chromatic aberration on. Light reflected from the measurement object is imaged by the imaging optical unit and the first beam splitter onto a first confocal detection stop arrangement, such that the first confocal detection stop arrangement functions as a confocal aperture. Light incident through the first detection stop arrangement is detected and evaluated by a first detection device. The measuring device has a first slit stop, which functions as a confocal aperture of the measuring device. The measuring device additionally includes a second detection device and a second beam splitter, wherein the second beam splitter splits the light reflected from the measurement object into a first and a second partial beam, which image the same spatial region of the measurement object.

Abstract: The invention relates to an optical measuring process for acquiring a surface topography of a measurement object. To this end, a measuring device with a measuring head in a measuring head guide device is provided for chromatic confocal acquisition of the surface topography or for spectral interferometric OCT acquisition of the distance to the surface topography. Firstly, spectrally broadband light of a light source from a fibre array with i fibres of i measurement spots is directed onto the measurement object via a common measuring head optic, with formation of a spot array of i measurement spots. i reflection spectra of the i measurement channels are then acquired and digitized. Finally, the digitized reflection spectra are evaluated with removal of time variations of systematic measurement errors and time-related deviation movements of the measuring head guide device.

Abstract: According to a method for measuring the distance between a workpiece and a machining head of a laser machining apparatus, a machining head is provided, which has a housing that has an interior and an opening for emergence of the laser radiation from the machining head. The laser radiation is directed on to the workpiece, after it has passed through the interior and the opening. An object beam is directed on to the workpiece by a light source of an optical coherence tomograph in such a manner that the object beam passes through the interior and the opening before being incident upon the workpiece. In addition to the object beam, a measuring beam passes through the interior. The measuring beam is used to compensate falsifications of the measured distance that have been caused by pressure fluctuations in the interior. The measuring beam in this case may be reflected at a reflective face that is formed on an inner face of an outlet nozzle that comprises the opening, which inner face delimits the interior.

Abstract: The invention relates to an optical measuring process for acquiring a surface topography of a measurement object. To this end, a measuring device with a measuring head in a measuring head guide device is provided for chromatic confocal acquisition of the surface topography or for spectral interferometric OCT acquisition of the distance to the surface topography. Firstly, spectrally broadband light of a light source from a fiber array with i fibers of i measurement spots is directed onto the measurement object via a common measuring head optic, with formation of a spot array of i measurement spots. i reflection spectra of the i measurement channels are then acquired and digitized. Finally, the digitized reflection spectra are evaluated with removal of time variations of systematic measurement errors and time-related deviation movements of the measuring head guide device.

Abstract: The invention relates to an optical measuring device for acquiring in situ a difference in distance between a support and an edge region of an object to be measured. The optical measuring device has a measuring head with dual beam guide which directs a first measuring beam towards the support and a second measuring beam towards the edge region of the object to be measured. Means are provided for acquiring and forming reflection spectra of the first measuring beam which is directed towards the support and the second measuring beam which is directed towards the edge region of the object to be measured. The measuring device has a multi-channel measuring apparatus with one spectrometer line. An evaluation unit for the reflection spectra for acquiring the stage height between the support and the edge region of the object works together with a spectrometer and a display unit.

Abstract: The invention relates to a test device for testing a bonding layer between wafer-shaped samples and a test process for testing the bonding layer. The test device comprises a measuring head for an OCT process that is configured to direct an optical measuring beam at a composite comprising at least two wafer-shaped samples with a bonding layer positioned between them. An optical beam splitter is configured to divert an optical reference beam as a reference arm for distance measurements. An evaluation unit is configured to evaluate layer thickness measurements without a reference arm and distance measurements with a reference arm. An optical switch device is configured to connect and disconnect the reference arm.

Abstract: An apparatus and method for determining a depth of a region having a high aspect ratio that protrudes into a surface of a semiconductor wafer are provided. The apparatus comprises a multi-wavelength light source, a semiconductor wafer holder for holding a semiconductor wafer, a head for directing the light source onto the semiconductor wafer, a spectrometer for collecting light comprising multiple wavelengths reflected from the semiconductor wafer and analysis means for determining a depth of the region from an interference pattern of light reflected from the semiconductor wafer by performing Fourier domain optical coherence tomography.

Abstract: Apparatus for monitoring a thickness of a silicon wafer with a highly-doped layer at least at a backside of the silicon wafer is provided. The apparatus has a source configured to emit coherent light of multiple wavelengths. Moreover, the apparatus comprises a measuring head configured to be contactlessly positioned adjacent the silicon wafer and configured to illuminate at least a portion of the silicon wafer with the coherent light and to receive at least a portion of radiation reflected by the silicon wafer. Additionally, the apparatus comprises a spectrometer, a beam splitter and an evaluation device. The evaluation device is configured to determine a thickness of the silicon wafer by analyzing the radiation reflected by the silicon wafer by an optical coherence tomography process. The coherent light is emitted multiple wavelengths in a bandwidth b around a central wavelength wc.