EP2347215A1 - Procédé et dispositif d'interférométrie - Google Patents

Procédé et dispositif d'interférométrie

Info

Publication number
EP2347215A1
EP2347215A1 EP09741220A EP09741220A EP2347215A1 EP 2347215 A1 EP2347215 A1 EP 2347215A1 EP 09741220 A EP09741220 A EP 09741220A EP 09741220 A EP09741220 A EP 09741220A EP 2347215 A1 EP2347215 A1 EP 2347215A1
Authority
EP
European Patent Office
Prior art keywords
signal
frequency comb
scan
interferometer
frequency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09741220A
Other languages
German (de)
English (en)
Inventor
Klaus KÖRNER
Wolfgang Osten
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Universitaet Stuttgart
Original Assignee
Universitaet Stuttgart
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Universitaet Stuttgart filed Critical Universitaet Stuttgart
Publication of EP2347215A1 publication Critical patent/EP2347215A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
    • G01B9/02002—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies
    • G01B9/02004—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies using frequency scans
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
    • G01B9/02007—Two or more frequencies or sources used for interferometric measurement
    • G01B9/02008—Two or more frequencies or sources used for interferometric measurement by using a frequency comb
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02034—Interferometers characterised by particularly shaped beams or wavefronts
    • G01B9/02035—Shaping the focal point, e.g. elongated focus
    • G01B9/02036—Shaping the focal point, e.g. elongated focus by using chromatic effects, e.g. a wavelength dependent focal point
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02041—Interferometers characterised by particular imaging or detection techniques
    • G01B9/02042—Confocal imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02055—Reduction or prevention of errors; Testing; Calibration
    • G01B9/02056—Passive reduction of errors
    • G01B9/02057—Passive reduction of errors by using common path configuration, i.e. reference and object path almost entirely overlapping
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/0209—Low-coherence interferometers
    • G01B9/02091—Tomographic interferometers, e.g. based on optical coherence
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/0004—Microscopes specially adapted for specific applications
    • G02B21/002—Scanning microscopes
    • G02B21/0024—Confocal scanning microscopes (CSOMs) or confocal "macroscopes"; Accessories which are not restricted to use with CSOMs, e.g. sample holders
    • G02B21/0052—Optical details of the image generation
    • G02B21/0056—Optical details of the image generation based on optical coherence, e.g. phase-contrast arrangements, interference arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B2210/00—Aspects not specifically covered by any group under G01B, e.g. of wheel alignment, caliper-like sensors
    • G01B2210/50—Using chromatic effects to achieve wavelength-dependent depth resolution
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B2290/00—Aspects of interferometers not specifically covered by any group under G01B9/02
    • G01B2290/25—Fabry-Perot in interferometer, e.g. etalon, cavity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B2290/00—Aspects of interferometers not specifically covered by any group under G01B9/02
    • G01B2290/30—Grating as beam-splitter

Definitions

  • white-light interferometry sensors based on the approaches described in [1] - [7] do not generally permit measurements on objects with distances between object and sensor in the range of one or several meters for measurements with a high volume minimization, since during measurement the optical path length in the reference arm must be made at least once equal to the optical path length in the object arm. This leads to a considerable volume of the sensor even in folded arrangements in the rule.
  • 7391 520 B2 [9] shows an OCT batch with a detector with a multiplicity of spectral channels, ie a spectrometer.
  • a spectrometer due to the particular necessity of using a spectrometer in the optical measuring system, an object can not be recorded in a planar or pictorial manner at one time, but as a rule only at points; So the areal detection of an object must be done laterally serial. This is certainly acceptable for the applications described in [8] and [9].
  • these approaches still do not allow any application for the measurement of macroscopic objects, but are limited for economic reasons to the measurement of comparatively small objects. Also, the measurement of objects of great depth and distance with such approaches is rather not possible.
  • the patent application DE 3623265 A1 in FIG. 7 shows a Fabry-Perot interferometer for measuring the position of a mirror in conjunction with a second interferometer for generating a spatially spread interferogram.
  • Object of the present invention is to provide a beauskalig customizable interferometry with high measurement and sampling accuracy and a high robustness of the measurement. This object is achieved by a method according to claim 1 and an apparatus according to claim 11. Preferred embodiments are subject of the dependent claims.
  • the invention thus provides a method of interferometry, which comprises: Generating an electromagnetic measurement signal (hereinafter also referred to as "light");
  • an interference signal by superimposing a portion of the scanning beam component reflected by the at least one object point on the reference beam component, wherein the portion of the scanning beam component reflected in the interference signal by the at least one object point has an optical path difference x_O relative to the reference beam component that depends on the position of the object point, in particular zero wherein the measurement signal is generated with a frequency comb spectrum with the same frequency comb intervals ⁇ f_Signal the individual frequency components and / or wherein the interference signal is conditioned or filtered by means of a frequency comb filter such that the filtered interference signal only a frequency comb spectrum with the same frequency comb intervals ⁇ f_Signal of the individual frequency components has; and wherein the method further comprises: temporally changing the frequency comb distances ⁇ f_Signal in the frequency comb spectrum of the measurement signal or the filtered interference signal and / or the optical path difference x_O such that the frequency comb intervals ⁇ f_Signal at least temporarily an integer multiple of the quotient
  • an electromagnetic measurement signal with a frequency comb spectrum is particularly preferably generated such that the frequency comb distances ⁇ f_Signal of the measurement signal (hereinafter also referred to as ⁇ f_Source) in a modulation interval [ ⁇ f_Signal_min; ⁇ f_Signal_max] (hereinafter also referred to as [ ⁇ f_Source_min; ⁇ f_Source_max]) of Frequency comb intervals are changed over time.
  • This temporal change can take place in various ways, as will be shown below in some examples.
  • a spectrum is referred to in a conventional manner, which is represented on the frequency composed of a plurality of equidistant frequency components, wherein the distances between adjacent frequency components in the frequency space as the frequency comb intervals ⁇ f_Signal be drawn. Not necessarily all frequency components must occur with the same intensity.
  • the intensity of the discrete frequency components is distributed according to or similar to a Gaussian curve, with the intensities of the frequency components decreasing from higher to lower frequencies starting from a central frequency.
  • the intensity or intensity change is preferably detected for a plurality of frequency comb distances ⁇ f_Source within the modulation interval around the at least one frequency comb resonance distance ⁇ f_Source_Res.
  • the intensity or intensity change is preferably detected for a multiplicity of different optical path differences x_O around at least one resonance condition.
  • a frequency comb modulation distance .DELTA.f_source_mod is determined from the detected values of the interference signal, in particular the intensity and / or intensity change, in particular as the frequency comb distance at the maximum modulation of the detected signal waveform of the interference signal and / or as the frequency comb interval at the signal maximum in the detected signal waveform of the interference signal and / or as a frequency comb spacing in the signal centroid of the detected signal waveform of the interference signal.
  • the determined frequency comb modulation distance ⁇ f_Quelle_Mod is stored and / or evaluated.
  • the frequency comb modulation distance .DELTA.f_Source_Mod determined in this way corresponds, to a good approximation, to the frequency comb resonance distance ⁇ f_Source_Res. Therefore, can be determined from the Frequency comb modulation distance ⁇ f_Source_Mod preferably information about the underlying optical path difference x_O, and thus determine an absolute and / or relative position of the at least one object point.
  • a spectrally integrating detector element is preferably used, at least in spectral subranges. This is in particular easier and cheaper to provide than high-resolution spectrometer, on the other hand, it achieves a particularly high sensitivity. Due to the possible omission of the use of complex, sensitive and high-resolution spectrometers for detection, the invention achieves a particularly simple and interference-insensitive interferometry with particularly high resolution, in particular for spatially resolved measurements or surveys or images of objects or their position in different sizes.
  • the principle according to the invention is not limited to a specific spectral range of the electromagnetic measurement signal or electromagnetic radiation (hereinafter also without limitation "light”) and / or a specific order of magnitude of the objects to be examined
  • the resolution capability is preferably limited only by diffraction effects of the electromagnetic radiation used, ie, it depends on the wavelength of the radiation used, a shorter wavelength thus preferably allowing a higher spatial resolution Resolution.
  • an excerpt, in particular a pixel or a cell, of a spatially resolving detector, in particular a detector array or detector array, having a multiplicity of optical detector elements is used as the optical detector element.
  • a high-resolution spectrometer eg a diffractive Grating spectrometer
  • a detector array also referred to as rasterized detector
  • a CCD camera and / or CMOS camera simultaneously a spatially two-dimensional image.
  • a spectral resolution is not required or already anticipated by the superposition of the resonance behavior of the two-beam interferometer and the frequency comb spectrum.
  • a spectrally integrating, rasterized detector is used, at least in spectral subareas.
  • generating the electromagnetic measurement signal comprises: generating an electromagnetic output signal having a continuous spectrum; and conditioning or filtering the output signal by means of a detunable multibeam interferometer for generating the electromagnetic measurement signal with a frequency comb spectrum such that the frequency comb intervals ⁇ f_Signal of the measurement signal in a modulation interval ([ ⁇ f_Signal_min; ⁇ f_Signal_max]) of the frequency comb intervals are changed over time.
  • a Fabry-Perot interferometer is preferably used as a multi-beam interferometer.
  • a superluminescent diode is used to generate the substantially continuous spectrum output signal.
  • the electromagnetic measurement signal is generated by means of a tunable frequency comb laser.
  • the method comprises determining a frequency comb modulation distance ⁇ f_Source_Mod from the detected values of the intensity and / or intensity changes of the interference signal (ie with the aid of or with the aid of the acquired values of the intensity and / or intensity changes of the interference signal), wherein the frequency-comb modulation distance ⁇ f_Source_Mod especially as frequency comb distance ⁇ f_Signal in the maximum modulation of the detected signal waveform of the interference signal; and / or as a frequency comb distance ⁇ f_Signal at the maximum signal in the detected waveform of the interference signal and / or; is determined as frequency comb distance ⁇ f_Signal in the signal center of gravity of the detected signal waveform of the interference signal.
  • the frequency comb distance ⁇ f_Signal is temporally changed in a predetermined manner, while the intensity and / or intensity change of the interference signal is measured or detected at a plurality of values of the frequency comb distance ⁇ f__Signal.
  • frequency comb modulation distance .DELTA.f_Source_Mod the value of the predetermined and changed frequency comb spacing .DELTA.f_Signal is preferably determined therefrom, wherein the maximum of the modulation of the detected signal waveform of the interference signal and / or the signal maximum in the detected waveform of the interference signal and / or the signal centroid of the detected waveform of the Interference signal occurs.
  • the signal center of gravity is preferably the mean value of the frequency comb distance ⁇ f_signal weighted with the magnitude of the detected values of the intensity and / or intensity changes of the interference signal.
  • the method comprises: a first scan (hereinafter also sometimes referred to as a long scan) in such a way that the frequency comb distances ⁇ f_Signal are thereby changed continuously; and a second scan (hereinafter also occasionally called short scan) executed repeatedly (in particular periodically) during the first scan, such that the optical path difference x_O is continuously changed such that the continuous change in the quotient c / x O caused thereby Sign after at least temporarily the first Scan effected continuous change of the frequency comb intervals .DELTA.f_Signal, wherein the detection of an intensity and / or intensity change of the interference signal takes place during each of the second scan.
  • a first scan hereinafter also sometimes referred to as a long scan
  • a second scan hereinafter also occasionally called short scan
  • the detection of an intensity and / or intensity change of the interference signal takes place in a period of the repeated second scanning process, in which the change of the frequency comb distances ⁇ f_Signal corresponds to the sign after the change of the quotient c / x_O.
  • the change of the frequency comb distances ⁇ f_Signal corresponds to the sign after the change of the quotient c / x_O.
  • the method comprises: a first scan (hereinafter also sometimes called a long scan) in such a way that the optical path difference x_O is continuously changed; and a second scanning process performed during the first scan (hereinafter occasionally also referred to as short scan) in such a way that the frequency comb distances ⁇ f_Signal are continuously changed such that the change of the frequency comb distances ⁇ f_Signal according to the sign at least temporarily corresponds to the continuous change in the quotient c / x_O caused by the first scan, the detection of an intensity and / or intensity change of the interference signal in each case taking place during the second scanning process.
  • a first scan hereinafter also sometimes called a long scan
  • a second scanning process performed during the first scan hereinafter occasionally also referred to as short scan
  • the detection of an intensity and / or intensity change of the interference signal takes place in a period of the repeated second scanning process, in which the change of the frequency comb distances ⁇ f_Signal corresponds to the sign after the change of the quotient c / x_O.
  • a reduction of the phase angular velocity in the interference image is efficiently effected during the creation of a photograph with the detector element.
  • an intensity and / or intensity change is detected during a detector integration period ⁇ tD during which the phase in the interference signal changes by no more than 180 degrees in magnitude.
  • the second scanning process preferably has a sawtooth curve of the optical path difference x_O or the reciprocal 1 / ⁇ f_signal of the frequency comb intervals ⁇ f_Signal over time, the detection of an intensity and / or intensity change of the interference signal occurring during the long edge of the sawtooth curve.
  • the second scanning process takes place in the form of a harmonic oscillation of the optical path difference x_O or of the inverse value 1 / ⁇ f_signal of the frequency comb distances ⁇ f_Signal over time, wherein the detection of an intensity and / or intensity change of the interference signal takes place in a period of time, which contains the passage of the harmonic oscillation through the point or point of inflection of the movement in the positional space (ie in particular that point with maximum speed) in which the change of the frequency comb distances ⁇ f_Signal corresponds to the sign after the change of the quotient c / x_O.
  • This preferably corresponds to the maximum point of the intensity or modulation in the interference signal.
  • the invention provides an apparatus for interferometry, comprising: a measurement signal source for generating an electromagnetic measurement signal; an interferometer arrangement which is designed to split the measuring signal, in particular by means of a beam splitter element of the interferometer arrangement, into a scanning beam component and a reference beam component; to irradiate at least one object point with at least a part of the scanning beam component, in particular by means of a lens of the interferometer arrangement; and an interference signal is generated by superimposing a portion of the scanning beam component reflected by the at least one object point on the reference beam component, wherein the portion of the scanning beam component reflected by the at least one object point in the interference signal has an optical path difference x_O relative to the reference beam component dependent on the position of the object point; wherein the measurement signal source is adapted to generate the measurement signal with a frequency comb spectrum with equal frequency comb intervals ⁇ f_Signal the individual frequency components and / or wherein the apparatus further comprises a frequency comb filter which is adapted to filter the interference signal
  • the interferometer arrangement comprises a Fizeau interferometer and / or a Michelson interferometer and / or a Twyman Green interferometer and / or a Mirau interferometer and / or a Linnik interferometer and / or a Mach-Zehnder interferometer.
  • the measurement signal source comprises a tunable frequency comb laser.
  • the measuring signal source comprises: a radiation source for generating an electromagnetic output signal with a continuous spectrum; and a frequency comb filter, in particular a tunable multi-beam interferometer, such as a Fabry-Perot interferometer, with an adjustable or variable delay length Y, for filtering the output signal for generating the electromagnetic measurement signal with a frequency comb spectrum such that the frequency comb intervals ⁇ f_Signal of Measuring signal in a modulation interval ([ ⁇ f_Signal_min; ⁇ f_Signal_max]) of the frequency comb intervals are temporally changeable.
  • a frequency comb filter in particular a tunable multi-beam interferometer, such as a Fabry-Perot interferometer, with an adjustable or variable delay length Y, for filtering the output signal for generating the electromagnetic measurement signal with a frequency comb spectrum such that the frequency comb intervals ⁇ f_Signal of Measuring signal in a modulation interval ([ ⁇ f_
  • the measuring signal source comprises a first signal scanning device for performing a first scanning or signal scanning operation (hereinafter also sometimes referred to as long scan) in such a way that an optical delay length or path length Y of the signal path in the measuring signal source is changed continuously , and a second signal scanning device for carrying out a second scanning or signal scanning process (hereinafter also occasionally also referred to as short scan) which is repeated (in particular periodically) during the first signal scanning, in such a way that the optical delay length or Path length Y of the signal path in the measuring signal source is continuously changed such that the change in the optical delay length by the second signal scanning operation is opposite to the sign after at least temporarily the change of the optical delay length by the first signal scanning operation.
  • a first signal scanning device for performing a first scanning or signal scanning operation (hereinafter also sometimes referred to as long scan) in such a way that an optical delay length or path length Y of the signal path in the measuring signal source is changed continuously
  • a second signal scanning device for carrying out a second scanning or signal scanning process (herein
  • the method for interferometry thus preferably comprises a corresponding first or second signal scanning process.
  • the detection of an intensity and / or intensity change of the interference signal takes place in each case during the second signal scanning process.
  • the detection of an intensity and / or change in intensity of the Interference signal in a period of the repeatedly performed second signal scanning operation in which the change of the optical delay length by the second signal scanning operation is opposite to the sign after the change of the optical delay length by the first signal scanning operation.
  • the first and second signal scanning device preferably form two spatially separate scanners (one for the long and one for the short scan) in the measurement signal source.
  • phase angle velocity preferably does not change at regular time intervals or only so slightly that an interference image can then be recorded by a screened detector in each case with particularly good resolution. This is especially advantageous for miniaturized measuring systems with a small numerical aperture, since then preferably no mechanical scanning process has to be performed on the sensor.
  • the device preferably comprises an optical waveguide for transmitting the measurement signal from the measurement signal source to the interferometer arrangement.
  • the control device is preferably designed to synchronously control a first and a second scanning process in such a way that the frequency comb distances ⁇ f_signal are changed continuously in the first scanning process; and in which the optical path difference x_O repeatedly executed during the first scan scan is continuously changed such that the continuous change in the quotient c / x_O caused thereby corresponds to the frequency comb distances ⁇ f_Signal according to the sign after at least the continuous scan caused in the first scan process and wherein the control device is designed to control the at least one detector element such that the detection of an intensity and / or Intensticians selectedung of the interference signal in each case during the second scan takes place.
  • control device is designed to synchronously control a first and a second scanning process such that in the first scanning process the optical path difference x_O is changed continuously; and in the second scan repeatedly executed during the first scan advance, the frequency comb distances ⁇ f_Signal are continuously changed such that the change corresponds to the frequency comb intervals ⁇ f_Signal following the sign after at least temporarily the continuous change in the quotient c / x_O caused by the first scan, and wherein the control device is designed to control the at least one detector element such that the detection of an intensity and / or intensity change of the interference signal takes place in each case during the second scanning process.
  • the invention achieves in particular measuring systems with a wide-scale customizable measuring or scanning accuracy - depending on the need from subnanometer resolution to millimeter resolution - the economic use to supply.
  • the goal here is also a high robustness of the measurement.
  • electromagnetic (optical) signals from these depths, for example, at object distances of the order of one meter, in a particularly suitable, especially particularly good evaluable waveform for a planar field of view or at least for a linear field of view. It can do it preferably many laterally adjacent object elements or object points become appropriate at the same time.
  • it is thus achieved to provide readily analyzable electromagnetic (optical) signals in the electromagnetic (optical) probing of objects by the method according to the invention by means of a camera which preferably measures areally and / or linearly.
  • the obtained electromagnetic (optical) signals lead in particular to comparatively good, in particular clearly evaluable measurement results.
  • color cameras can be used as detectors.
  • the term light is always used as a synonym for electromagnetic radiation, in particular from the terahertz, over the infrared to the deep UV range.
  • Another advantage here is also to be able to measure with wide scale, with different, trained according to the inventive approach sensors, each in all three spatial coordinates - including the depth.
  • This is preferably also possible in a measuring volume of, for example, 20 ⁇ m ⁇ 20 ⁇ m ⁇ 20 ⁇ m up to one cubic meter.
  • the limits with regard to the ascertainable measurement volume upwards are determined only by the available light energy and also by the available measurement time.
  • the microscopic scale preferably only the diffraction limit makes A limiting factor in the lateral resolution noticeable, whereby the achievable effective lateral resolution can be further increased by means of suitable numerical methods.
  • With the depth resolution a subnanometer resolution is achieved when using suitable components.
  • a sensor has comparably small dimensions.
  • Fields of application of the inventive solution are in particular: the microform and the microprofile measurement, the measurement of roughness as well as the mini-form measurement, the shape measurement on no or little cooperative surfaces, as well as e.g. human liver tissue.
  • An example of the application of the invention here is also the detection of the microform on the inner ear in humans in the surgical operation phase and the intraoral shape detection of human teeth.
  • Another preferred field of application of the invention is the form detection on technical teeth in gears and on objects with a high aspect ratio.
  • a preferred field of application is the highly accurate measurement of the shape of partially reflecting, weakly light scattering and thereby strongly inclined gear tooth surfaces.
  • Another preferred field of application is the measurement of polished and unpolished aspheres in transmission as well as specular aspheres, spectacle lenses and free-form surfaces, in particular for optical imaging.
  • the invention can also be used in particular for geometric measurements in ophthalmology.
  • the use in endoscopic 3D systems leads to well-miniaturized sensor solutions with high measurement accuracy.
  • the invention is in particular also for the determination of the optical thickness n '* d, with n' as optical refractive index and d as the geometric path length, or the optical path lengths n '* d of biological micro-objects, cells or cell components in the label-free diagnostics and analysis used.
  • cells or cell components can be measured laterally with high resolution, that is also with images, with regard to the distribution and variation of their optical thicknesses.
  • living cells or constituents of living cells can also be detected pictorially in transmitted or incident light with regard to the optical thick distributions or their changes in a process.
  • an optical volume memory for example in the form of an optical multi-layer memory
  • the method preferably also for fast reading optical data from optical volume storage can be used.
  • the invention provides a method and an apparatus or arrangement for scalable confocal interferometry in transmitted light or reflected light in a scanning measuring process for the relative or absolute depth measurement or distance measurement of a technical or biological object or object elements, for microscopic, mesoscopic or macroscopic 2D or 3D acquisition of technical or biological objects or for OC tomography or OC microscopy or for endoscopic 2D or 3D metrology or for measuring layer thicknesses, resolved laterally or over time, or their lateral or temporal changes.
  • an optical volume memory for example in the form of an optical multi-layer memory
  • the method can be used in particular for the rapid readout of optical data from optical volume stores.
  • the presence and the geometric distribution of reflective or light-scattering elements in a volume of a data carrier are detected.
  • chromatic-confocal object-imaging interferometer with at least approximated two-beam characteristic - ie with a predetermined chromatic depth splitting of foci in the object space
  • At least one light source in which case light in the sense of electromagnetic radiation of terahertz over IR, VIS to UV radiation is understood.
  • the object-imaging interferometer preferably has a non-zero optical path difference x_O at each optically detected object element.
  • This should preferably be at least two micrometers.
  • the optical path difference can typically be much larger - in extreme cases up to the range of several millimeters or up to several meters.
  • the size ⁇ f_object corresponds exactly to the period length in the wavelet.
  • a spectrally integrally detecting, rasterized detector that is to say for example with very many with pixels, is arranged for this electromagnetic radiation.
  • this screened detector is thus preferably formed with a single spectral channel in each pixel. So this can be a common grayscale CCD or grayscale CMOS camera that only registers gray values but no colors in each pixel.
  • the use of a color camera is possible, which is also not yet regarded as a spectrometer, but as a camera with three or four spectral channels.
  • the light source is formed as a frequency comb light source in the optical system.
  • the frequency comb preferably covers a certain spectral range.
  • the frequency comb distances of the light source .DELTA.f_Source are changed in the measurement process gradually over the time predetermined in the entire spectral range of the light source.
  • These frequency comb intervals can change in the range of a few parts per thousand up to a few percent of the initial value. In extreme cases, the changes may even be a multiple or a small fraction of the output value of the frequency comb distances ⁇ f_Source.
  • These changes in the frequency comb distances ⁇ f_Source can thus - made relatively large - be made very large.
  • the light source is represented by a spectral continuum light source or at least by a quasi-continuum light source, and this light source is preferably followed by a multi-beam interferometer with predetermined change in the optical delay length Y of the multi-beam interferometer in the measurement process that at least approximately a frequency comb characteristic is formed in the detection.
  • This reordering refers to the entire space of the optical system, including the space immediately in front of the screened receiver, , ie in the detection beam path. So the multi-beam interferometer is always downstream of the light source and upstream of the rasterized detector.
  • the delay length Y 2 L with L as the distance of the interferometer end mirror. This applies exactly only to a vacuum arrangement, or approximately for an air arrangement, when the refractive index is approximated by the value one.
  • a frequency comb laser having an optical delay length Y.
  • This frequency comb laser is formed with an at least approximately equidistant frequency comb, but over the time predetermined variable frequency intervals ⁇ f_Source of the maxima or spikes in the frequency comb.
  • This equality is produced by varying the delay path length Y in the light source at least once during the measurement process for each object object or object being probed, whereby a short-period modulation in the signal sequence occurs.
  • This waveform is repeatedly scanned over time by means of spectrally integrally detecting, rasterized detector, wherein at least one pixel of this spectrally integrally detecting, rasterized detector is optically associated with each of an object element.
  • the pixels of a color camera can here also be regarded as spectrally integrally detecting sensor elements in comparison to the sensor elements of a spectrometer.
  • the refractive index can generally be well approximated with the value one, especially on the microscopic scale. It is also possible that for different object elements i only changes in the delay length Y_Mod i for the different object elements i are determined and evaluated by the actual distances L_Mod i the end mirror of the multi-beam Interferometers are determined and stored and the calculation of the associated optical path differences x_O i made accessible.
  • the rastered detector of electromagnetic radiation is successively read out several times, and in each pixel of the rasterised detector the intensities are summed up, at least in part, spectrally integrally.
  • the detector can be a planar monochrome CCD or a CMOS camera.
  • each object element is assigned at least approximately one pixel by optical imaging.
  • coarse information about object distances can be obtained in the chromatic-confocal approach by evaluating the intensities in the color pixels.
  • the detector is a color CCD or color CMOS camera. Then each object element is assigned three or four pixels, but in different spectral ranges.
  • the determination of the optical path difference x_O or its changes ⁇ x_O over time may also be the target of the measurement alone, for example in the measurement of thin biological objects.
  • chromatic depth splitting In the case of chromatic depth splitting, confocal discrimination of the total spectrum of the light source, also referred to as the global spectrum, in the chromatic-confocal approach always uses only a partial region, ie. it only contributes to a part of the total spectrum of the light source for signal formation in the pixels of the screened detector.
  • the chromatic depth splitting therefore increases the depth, distance or distance measuring range at a given numerical aperture, but at the same time reduces the depth resolution, since the half-width of the detected signal increases with decreasing spectral range used. This reduces the depth measurement resolution.
  • Distance measurement range and distance measurement resolution to be selected in the measurement by the choice of the size of the chromatic power of a sensor and thus the coming to detection spectral width of the light used. If there is no chromatic splitting in the sensor, only the width of the total spectrum of the light source, ie the wavenumber range contributing to the detection, determines the achievable depth measurement resolution. In arrangements with an object-imaging system with a rather small or very small numerical aperture for measurements on a coarse scale, the chromatic depth splitting can be completely dispensed with if the wave-optical depth of field is sufficiently large for the measurement task.
  • the signal modulation in the detected signal profile is preferably evaluated for determining the absolute or relative object depth, if the case occurs when the frequency comb is changed in a predetermined manner
  • n 1. Then, there is no subsampling of the signal curve and, as a rule, a comparatively good signal-to-noise ratio is produced.
  • the necessary scan path or scan area is advantageously reduced by the factor n of the undersampling.
  • the waveforms then may need to be sampled finer in depth, as these then become narrower in width over the wavenumber.
  • the light source is designed as a frequency comb light source with a fixed optical retardation length Y in the optical system, preferably as a frequency comb microsampler, as already described in the 2007 literature.
  • the frequency comb distances ⁇ f_Source are thus kept constant.
  • the optical path difference x of the object-imaging interferometer is consequently altered by moving this object-imaging interferometer as a compact miniaturized module in the depth direction sensitively in the measurement process in relation to the object and the rasterized detector is read several times. Again, the signal waveform is evaluated in the occurrence of the equality of optical path difference x_O in an object element and optical delay length Y.
  • the object-imaging interferometer is preferably designed as a slim, miniaturized Fizeau interferometer, which thus has common path properties. Moving such an optical system mechanically sensitively in the direction of light is in many cases technically feasible.
  • the size of the chromatic refractive power in the object-imaging interferometer, whereby the degree of depth splitting changes can be adapted specifically to the depth of the object to be measured.
  • the light source can be constructed, for example, from individual light sources, for example superluminescent diodes, each having a downstream Fabry-Perot interferometer.
  • the Fabry-Perot interferometer is upstream of the rasterized detector.
  • the superluminescent diodes are operated and switched individually or in smaller groups, in order to work with well-adapted spectral ranges, in order to generate well-evaluable optical signal characteristics for the respective object.
  • controllable spectral filters when using strong light sources, which the width of the control and adjust the spectrum used.
  • the width of the control and adjust the spectrum used For a strong dispersion in the optical medium of the object space can greatly reduce the modulation depth in the signal curve if the spectral range used is too broad.
  • a strong limitation of the spectral range used ie the wavenumber or frequency range, brings about a reduction in the measurement accuracy by increasing the half-width of the signal, the measurement is possibly made possible in the first place.
  • the optical path difference, or the optical path length, in a point or element of a micro-object, for example a living cell can be detected. That is, the geometric path length is not or less of interest. This may be of great interest in marker-free monitoring of biological cells or cell constituents, since the information on the course of subcellular processes is significantly reflected in many processes, above all in the change in the optical path length. This change is then measured in high resolution over time.
  • deposits of extremely thin layers on substrates can also be detected. These layers may consist of proteins, for example.
  • the elimination of the dispersion can be done in any case by using the same media, usually liquids, in the object space and in the multi-beam interferometer or laser resonator, wherein the optical attenuation of the medium is observed.
  • the optical path difference, or the optical path length, in a point or element of a micro-object can be detected. This may be of great interest in the marker-free monitoring of biological cells or cell constituents, since the information on the progress of subcellular processes is significantly reflected in the change in the optical path length. This is then measured high-resolution over time.
  • the dispersion of the multi-beam interferometer can preferably be made at least approximately equal to the dispersion in the object space. This is well possible when measuring biological objects in aqueous solution in which the multi-beam interferometer, preferably an encapsulated Fabry-Perot interferometer, is also operated in water, so that multi-beam interference takes place in the Fabry-Perot interferometer in water. This leads to signal curves with a high degree of modulation, since the dispersions can be adjusted quite well.
  • FC long scan with the time ⁇ t_lang_fc, since this is preferably continuous and preferably at least as is performed long as a modulation occurs in the waveform, so a variable interference pattern at the output of the object-imaging interferometer arises.
  • this FC long scan is to be carried out via the change ⁇ y in the delay length Y in a multi-beam interferometer or via the change ⁇ y in the optical delay length Y in the resonator of a frequency comb laser.
  • at least three short scans synchronized with this FC long scan are preferably performed simultaneously with the long scan, ie the predetermined scan of the frequency distances of the light source, either in the reference arm or in the object arm of the object-imaging interferometer, which scans are significantly shorter in their time duration ⁇ t_kurz_lnt as the duration ⁇ t_lang_fc of the long scan.
  • phase angle velocity in the rasterized detector causes - at least for a portion of the time ⁇ t_kurz_lnt - a reduction in the phase angle velocity in the rasterized detector to be picked interference image, including a phase angle velocity with the amount zero, by in the period .DELTA.t_kurz_lnt both the amount of the delay length Y and the amount of optical retardation x_O each increase both or each reduce both.
  • the resulting phase angular velocity d ⁇ / dt in radians is thus at least in the long scan of the frequency comb light source synchronized short scan of the object imaging interferometer approximately:
  • phase angular velocity d ⁇ / dt becomes zero when the magnitudes and the sign of n ⁇ Y and ⁇ x_O in the time period ⁇ t_kurz_lnt are the same.
  • These short scans which change the optical path difference in the object-imaging interferometer, are preferably carried out in the reference arm with advantage if the object-imaging interferometer is designed with a chromatic-confocal beam path in the object arm.
  • the object-imaging interferometer is designed with a chromatic-confocal beam path in the object arm.
  • there is thus a chromatic depth splitting which allows a sharp image of the optically touched object elements in the measuring range, so that a scan in the object arm is usually superfluous.
  • This also has constructive advantages for a miniaturization of the measuring device or arrangement, since the object arm can thus remain free of movement means.
  • the short scans can preferably also be carried out in the object arm.
  • the change in the optical path difference ⁇ x_O in the object-imaging interferometer in a short scan is more likely to be one-tenth of the change n ⁇ Y, or even less.
  • the phase in the interference image changes by a maximum of 180 degrees in magnitude, but typically only in the amount between zero degrees and 90 degrees.
  • the case of zero-degree phase change in the detector integration period ⁇ tD means that the FC long scan and each short scan are exactly synchronized.
  • Delay length Y is made in a resonator of a frequency comb laser.
  • the duration of a short scan ⁇ t_kurz_lnt can be at least approximately the same the detector integration period .DELTA.tD be made.
  • the interference phenomenon in the detected pixels of the rasterized detector in the detector integration period ⁇ tD then remains at least approximately unchanged in practice.
  • the optical path difference in the object-imaging interferometer or in a multi-beam interferometer or in the resonator of a frequency comb laser synchronized working piezo actuator can be arranged.
  • the short scans further at least approximately a sawtooth curve of the optical path difference x_O of the object-imaging interferometer over time, wherein the inclusion of interference images by rasterized detector within the period .DELTA.t_kurz_lnt in the sawtooth preferably takes place when the long edge of the tooth is traversed.
  • the length of time for the long edge preferably corresponds at least approximately to the integration time duration ⁇ tD of the rastered detector.
  • the amount of change in the optical path difference in the object-imaging interferometer between two directly successive short scans is freely selectable.
  • the magnitude of this change in magnitude is at least approximately equal to the magnitude of the centroid wavelength in the spectrum used.
  • short scans are preferably performed at least approximately in the form of a harmonic oscillation.
  • the inclusion of interference images by means of rastered detector takes place within the period ⁇ t_kurz_lnt preferably in at least approximately linear part of the path-time curve of the oscillation, wherein the oscillation amplitude is chosen so that the phase change of the interference in the detector integration period .DELTA.tD is at most 180 degrees, rather but preferably a value below 90 Old degree approximates.
  • the image pickup frequency is preferably made equal to the frequency of the harmonic oscillation or an integral multiple thereof.
  • At least three short scans are preferably carried out per FC long scan and thus at least three interference images are recorded by means of a rasterized detector in the FC long scan.
  • at least ten short scans are preferably carried out, and thus ten interference images are recorded in the FC long scan, but usually preferably hardly more than one hundred interference images.
  • typically at least one hundred to one thousand interference images would need to be captured in the FC long scan, or it would be necessary to work with short exposure during detection. This is relatively technically complicated or time consuming.
  • the rastered detector can be designed as a monochrome or color matrix CCD or CMOS camera.
  • a chromatic-confocal, object-imaging interferometer with at least approximately two-beam characteristic - ie with a predetermined chromatic depth splitting of foci in the object space
  • At least one light source in which case light in the sense of electromagnetic radiation of terahertz over IR, VIS to UV radiation is understood.
  • the object-imaging interferometer at each optically detected object element on a preferably different from zero optical path difference.
  • This should preferably be at least two micrometers.
  • the optical path difference in the interferometer typically also be much larger - in the extreme case to the range of several millimeters to several meters.
  • the size ⁇ f_object corresponds exactly to the period length in the wavelet.
  • At least one raster detector which is spectrally integrally detecting at least in spectral subareas, is arranged for this electromagnetic radiation.
  • the light source is in the optical as a frequency comb light source
  • either the light source is represented by a spectral continuum light source or at least by a quasi-continuum light source and this light source is followed by a multi-beam interferometer with predetermined measurement of the simple optical delay length Y of the multi-beam interferometer.
  • the multi-beam interferometer is provided with means for varying the simple optical delay length Y.
  • the multi-beam interferometer preferably has a high finesse in order to achieve good discrimination.
  • the light source is represented by a frequency comb laser with the optical delay length Y and this frequency comb laser is formed with an at least approximately equidistant frequency comb, but over the time predetermined variable frequency intervals .DELTA.f_Source of maxima or spikes in the frequency comb.
  • This frequency comb laser is provided with means for varying the simple optical delay length Y.
  • the frequency comb laser may also be designed as a terahertz laser. It is also possible that the frequency comb laser is preferably formed with a micro-resonator, ie a comparatively small optical delay length Y, with a wavelength range in the infrared range between 1400 nm and 1700 nm and a frequency spacing of several 100 GHz.
  • a plurality of frequency comb lasers are operated in parallel, for example one each in the red, in the green and in the blue spectral range and for detection, preferably a conventional RGB three-chip color camera is used. Then each object element optically preferably three pixels (RGB) are assigned.
  • RGB three pixels
  • the multi-beam interferometer may preferably be formed by means of a cyclic fiber optic fiber arrangement.
  • the tuning of the multi-beam interferometer is preferably carried out by a highly dynamic, computer-controlled mechanical stretching of the fibers.
  • the fibers are preferably wound on a computer-controllable piezo-expansion rod.
  • a further preferred apparatus or arrangement for scalable confocal interferometry in transmitted light or reflected light for the relative or absolute depth measurement or distance measurement of a technical or object elements for microscopic, mesoscopic or macroscopic 2D or 3D detection of objects or for OC tomography or OC microscopy or for endoscopic 2D or 3D metrology of technical or biological objects or for determining layer thickness in a scanning measuring process, the following means are used:
  • a chromatic-confocal, object-imaging interferometer with at least approximately two-beam characteristic - ie with a predetermined chromatic depth splitting of foci in the object space - and at least one light source, in which case light in the sense of electromagnetic radiation of terahertz over IR, VIS to UV radiation is understood.
  • the light source represented by a spectral continuum light source or by a quasi-continuum light source and this light source downstream of a multi-beam interferometer.
  • the light source is preferably on the other hand represented by a frequency comb laser with the optical delay length Y.
  • This frequency comb laser is preferably formed with a micro-resonator.
  • the object-imaging interferometer always has a non-zero optical path difference x_O at each optically detected object element.
  • the size ⁇ f_object corresponds exactly to the period length in the wavelet.
  • At least one raster detector which is spectrally integrally detecting at least in spectral subareas, is arranged for this electromagnetic radiation.
  • the object-imaging interferometer means are predetermined
  • the optical path difference x_O is equal to the fixed optical retardation length Y when changing the optical path difference, and a modulated signal waveform can be detected from the at least approximately knowledge of the refractive index in the object medium depth or distance information for an object element at least approximately mathematically be determined.
  • the sensor is tuned so that the optical delay length Y is set so that if this delay length Y and optical path difference x_O in an object element is equal to a sharp image of this object element to a pixel of the screened detector.
  • the multi-beam interferometer or the frequency comb laser is preferably constructed with optical waveguides.
  • the multi-beam interferometer or the frequency comb laser preferably has a cyclic beam path.
  • the object-imaging interferometer may preferably also be designed as a Fizeau interferometer, Michelson interferometer, Twyman-Green interferometer, Mirau interferometer, Linnik interferometer - also with triple reflector in the reference arm - or Mach-Zehnder interferometer.
  • an imaging system for object illumination and object detection is assigned to the interferometer.
  • an optical volume memory for example in the form of an optical multi-layer memory
  • the method can basically also be used for fast reading of optical data from optical volume stores , In this case, the presence and the geometric distribution of reflective or light-scattering elements in a volume of a data carrier are detected.
  • the following describes a preferred method for scalable interferometry in transmitted light or incident light in a scanning measuring process.
  • At least one light source in which case light in the sense of electromagnetic radiation of terahertz over IR, VIS to UV radiation is understood.
  • the object-imaging interferometer has a non-zero optical path difference x_O at each optically detected object element.
  • This optical path difference x_O should have at least the magnitude of the shortest wavelength of the light source coming to the detection.
  • the optical path difference can typically be much larger - in extreme cases up to the range of several millimeters or even up to several meters.
  • On the basis of this optical path difference x_O have the maxima one - to an optically detected object element respectively associated - at least approximately sinusoidal frequency wavelet computationally a frequency spacing of
  • ⁇ f_object c / x_O on - with c equal to the vacuum speed of light and x_O equal to the optical path difference in the object-imaging interferometer associated with the respective optically detected object element.
  • the size ⁇ f_object corresponds to the period length in the wavelet.
  • a spectrally integrally detecting, at least in spectral subranges, rasterized detector that is, for example, with a great many pixels, arranged for this electromagnetic radiation.
  • this screened detector is therefore preferably formed with a single spectral channel in each pixel. So this can be a common grayscale CCD or grayscale CMOS camera that only registers gray values but no colors in each pixel.
  • the use of a color camera is possible, which is also not yet regarded as a spectrometer, but as a camera with three or four spectral channels.
  • the optical path difference in the measurement of an object, ie in the measuring process, in the object-imaging interferometer changes at least approximately continuously or quasi-continuously changed, wherein either the optical path in the object arm or the optical path in the reference the same is changed at least approximately continuously, so an interferometer remains unchanged in each case.
  • This change in gait represents an interferometer long scan which takes place in the time period ⁇ tjangjnt.
  • the light source is formed as a frequency comb light source in the optical system.
  • the frequency comb covers a certain spectral range.
  • the frequency comb distances of the light source ⁇ f_Source are changed in the measurement process over time, predetermined in the entire spectral range of the light source. These changes in the frequency comb distances ⁇ f_Source are called Short scans, which are performed in the period .DELTA.t_kurz_fc and synchronized to the interferometer long scan and the rasterized detector
  • the light source on the one hand by a spectral continuum light source or at least by a quasi-continuum light source is shown and this light source is a multi-beam interferometer with predetermining in the measurement changing the optical delay length Y of the multi-beam interferometer, so that at least approximately a frequency comb characteristic is formed in the detection.
  • This reordering refers to the entire space of the optical system, including the space immediately in front of the rasterized receiver, ie in the detection beam path. So the multi-beam interferometer is always downstream of the light source and upstream of the rasterized detector.
  • the delay length Y 2 L with L as the distance of the interferometer end mirror. This applies exactly only to a vacuum arrangement, or approximately for an air arrangement, when the refractive index is approximated by the value one.
  • This frequency comb laser is formed with an at least approximately equidistant frequency comb, but over the time predetermined variable frequency intervals ⁇ f_Source of the maxima or spikes in the frequency comb
  • the predetermined change of the frequency comb with respect to the frequency intervals of the maxima or spikes is performed by means of predetermined changes of this optical delay length Y as a short scan and in the period ⁇ tjangjnt of the interferometer long scan at least three short Scan performed the frequency comb light source.
  • the time duration ⁇ tjangjnt is at least three times as long as the time duration ⁇ tj ⁇ irzjc.
  • At least three FC short scans synchronized to this interferometer long scan are thus simultaneously carried out for the interferometer long scan, either in the reference arm or in the object arm of the object-imaging interferometer, which in their time duration ⁇ t_kurz_fc is significantly shorter than the time duration ⁇ tjangjnt of the Long scans are done.
  • These short scans preferably cause - at least for a portion of the time ⁇ t_kurz_fc - a reduction in the phase angle velocity in the rasterized detector to be included interference image, including a phase angle velocity with the amount zero, by in the period .DELTA.t_kurz_fc both the amount of the delay length Y and the amount of the optical path difference x_O each enlarge both or both reduce in size.
  • phase angular velocity d ⁇ / dt in radians is thus at least approximately in each case in the short scan of the frequency comb light source:
  • the phase angular velocity d ⁇ / dt becomes zero when the magnitudes and the sign of n * ⁇ Y and ⁇ x_O are equal in the period ⁇ t_kurz_lnt.
  • phase angular velocity d ⁇ / dt can also reach zero due to the synchronization of the interferometer long scan and FC short scan, so that the interference pattern does not change in the time period ⁇ t_kurz_fc.
  • the optical path difference x_O in the object-imaging interferometer then amounts to an integer multiple of the delay length Y in the frequency comb light source at least approximately in the time duration ⁇ t_kurz_fc of at least one single short scan
  • ⁇ t_kurz_fc of at least one FC short scan at least approximately:
  • This equality is achieved by preferably continuously varying the optical path difference x_O of the object-imaging interferometer generated at least once and at least approximately in the measuring process for each probed object element or object.
  • the waveform is repeatedly sampled in the period of time ⁇ tjangjnt by means of spectrally integrally detecting, screened detector, wherein at least one pixel of this spectrally integrally detecting, rasterized detector is optically associated with each of an object element.
  • the pixels of a color camera can here also be regarded as spectrally integrally detecting sensor elements in comparison to the sensor elements of a spectrometer.
  • the depth position of each object element in the occurrence of the modulation of the waveform by the object-forming interferometer or components thereof associated Wegmesssystems, for example on the object itself or, for example, on the mechanical basis of the object-forming interferometer, and a scaling of the value " ⁇ f p_Mod" on the measured values the distance measurement are determined.
  • the rastered detector of electromagnetic radiation is read out several times successively, and in each pixel of the rasterized detector, the intensities are at least partially summed spectrally in their entirety.
  • the detector can be a planar monochrome CCD or a CMOS camera.
  • each object element is assigned at least approximately one pixel by optical imaging.
  • the detector is a color CCD or color CMOS camera. Then each object element is assigned three or four pixels, but in different spectral ranges.
  • the determination of the optical path difference x_O or its changes ⁇ x_O over time may also be the target of the measurement alone, for example in the measurement of thin biological objects.
  • a relative movement is carried out between the object-imaging interferometer or at least components thereof and the object, so that a focussing in the object space takes place in the time duration ⁇ tjangjnt, and at least at one point in time ⁇ tjangjnt the object or Elements of the object are at least approximately sharply imaged optically.
  • the short scans preferably at least approximately have a sawtooth curve of the optical delay length Y over time.
  • the inclusion of interference images by means of a rastered detector within the time period ⁇ t_kurz_fc preferably takes place when the long edge of the tooth is traversed during the sawtooth curve.
  • the amount of change in the optical path difference in the object-imaging interferometer between two directly successive short scans is preferably freely selectable.
  • short scans are preferably performed at least approximately in the form of a harmonic oscillation and the recording of interference images by rastered detector preferably takes place in the at least approximately linear part of the course of the delay length Y over the time of the oscillation within the period ⁇ t_kurz_fc.
  • the oscillation amplitude is furthermore preferably selected such that the phase change of the interference in the detector integration period ⁇ tD is at most 180 degrees.
  • the image pickup frequency of the rasterized detector is preferably selected to be equal to the frequency of the harmonic oscillation or an integral multiple thereof.
  • the imaging of the object can preferably be carried out in a telecentric, central perspective or pericentric manner, the latter for example for the minimally invasive surgical technique, laparoscopy.
  • the light source may preferably be formed as a frequency comb laser with a macro-resonator with frequency spacings of several 100 MHz.
  • This macro-resonator can be designed to be tunable in frequency comb with respect to its frequency intervals.
  • the light source may preferably be formed on the other hand as a frequency comb laser with a micro-resonator with frequency intervals of several 100 GHz.
  • This micro-resonator can be designed to be tunable in frequency comb with respect to its frequency intervals.
  • the object imaging system must be designed to be at least approximately diffraction-limited, since otherwise no well evaluable signals.
  • the magnitude of the chromatic refractive power in the object illumination and imaging is preferably selected so that the resulting depth splitting of the foci is adapted in each case to the depth of the object to be measured. Thus, refocusing of the object-imaging system is not necessary.
  • FIG. 1 shows the sensor on the basis of a chromatic-confocal, two-beam spectral interferometer with a multi-beam interferometer arranged downstream of the light source for a relatively small object field with respect to the focal length of the object-imaging system.
  • the light from a high-intensity, fiber-coupled superluminescent diode 1 a in the near infrared range is coupled by means of focusing optics 2 in a single-mode fiber 3, exits from this at the output 4 of the singlemode fiber 3 again, is collimated by a lens 5 and enters a Fabry Per-interferometer 6, here designed as a Fabry-Perot interferometer 6 with the mirror spacing L, which is associated with a piezo actuator 25a.
  • a Fabry Per-interferometer 6 here designed as a Fabry-Perot interferometer 6 with the mirror spacing L, which is associated with a piezo actuator 25a.
  • an optical isolator not shown here, which should apply to all subsequent embodiments.
  • This Fabry-Perot interferometer has two highly mirrored semitransparent mirrors 7 and 8 with the mirror spacing L, so that high-finesse multi-beam interference exists at the output of the Fabry-Perot interferometer 6.
  • a multi-beam interference spectrum with frequency comb characteristic is generated.
  • the transmitted, narrow-band spectral components form a comb with equidistant distances ⁇ f_Source in the wavenumber space, the k-space, or the frequency space, the f-space.
  • the distances of the maxima of the transmitted, narrow-band intensities always have the same wavenumber difference .DELTA.f_source because of the multi-beam interference.
  • the light leaving the Fabry-Perot interferometer 6 with spectral comb characteristic passes through a beam splitter 9 and reaches a microlens array 10 with microlenses 11. Foci are formed. These are imaged by the lens 12 to infinity.
  • the light passes in the focal plane of the objective 12 a diffractive zone lens 13 with a light-diffusing effect, which is designed as a phase grating.
  • zeros are formed in the zeroth order, which act as reference bundle R_0, and bundles in the first order O_1 ⁇ , which bundles represent chromatic-depth-split, discretized object bundles which, after focusing by means of GRIN lens 14 and refractive surface 16, have different depth positions of the focuses Form object space, so that over the wavelength ⁇ for each imaged focus of a microlens a discretized focus chain 18 is formed, but only at those points in the spectrum where transmission through the transmission maxima of the comb spectrum of the Fabry-Perot interferometer 6 exists.
  • the objective 12, the diffractive zone lens 13, the GRIN lens 14 and the refractive surface 16 together form a chromatic imaging system 15.
  • the reference beams R_0 which have arisen in the zeroth diffraction order after the diffractive zone lens 13, become focused on the refractive surface 16 focused, whereby there arises a relatively small field of Foki, said refractive surface 16 also represents the reference surface in the two-beam interferometer.
  • On the refractive Surface 16 is a beam splitter layer 17 with a relatively low reflectance.
  • the reference beams R_0 are reflected back into the sensor after reflection at the beam splitter layer 17.
  • the bundles in the first order O_1 ⁇ reach the object space, where the object 19 is located, which is hit exactly or at least approximately in each object element by one of the focuses of the focus chain 18.
  • the lens 22 is used the image on the CCD camera 23, so that in each pixel of this CCD camera 23 each consist of a reference beam and in the presence of a detected object element also a confocal discriminated object bundle. Interference arises between these bundles. Due to the confocal discrimination, only light from the object bundles O_1 ⁇ _1 comes to pixels of the CCD camera 23, which was focused approximately sharply. Object bundles, that is, which were imaged at least approximately sharply on the surface of the object 19 with a wavelength ⁇ , are also sharply imaged onto a pixel of this CCD camera 23 by the design of the optical arrangement.
  • FIG. 2 shows the intensity striking a pixel 23a of the CCD camera 23-as the mirror distance L in the Fabry-Perot interferometer 6 changes-from a detected object element of the object 19 imaged on the pixel 23a.
  • the optical system is dispersion-free and has a negligible phase offset. Shown is the intensity profile in the form of a wavelet on the pixel 23a of the CCD camera 23 when the mirror distance L is changed in the Fabry-Perot interferometer 6 at a constant speed and the case .DELTA.f_ pi equal ⁇ f_Source when changing the mirror distance L is reached and traversed.
  • the object element touched by the pixel 23a is 1 mm away from the reference surface 16.
  • the light source 1 a in this case has a spectrum with gaussian envelope with the wavelength range of 720 nm to 920 nm.
  • This is in particular a theoretically expected wave packet (wavelet), which would result from an interference of a component of an incident light with a continuous Gaussian spectrum reflected at the object 19 and a component 19 reflected from the object 19.
  • This object wavelet could possibly even be detected in an optical system according to FIG. 1 by means of a suitable continuum light source and by means of a high-resolution spectrometer, if the Fabry-Perot interferometer 6 is then removed and the continuum light source has a Gaussian profile in the spectrum having.
  • the wave packet shown in FIG. 3 does not arise directly. However, this wave packet illustrates the interference condition in the used two-beam interferometer.
  • the frequency spacing ⁇ f_source decreases.
  • FIG. 4 shows the transmission of the Fabry-Perot interferometer 6 in FIG. 4 and FIG.
  • it is not directly related to the spectrum of the light emerging in the embodiment of FIG. 1 at the Fabry-Perot interferometer 6, which likewise has only a finite spectral width, for example due to a finite spectral width of the light source used.
  • ⁇ f_source ⁇ f_object at an object point P of the object 19 in FIG. 1.
  • a signal modulation occurs in the signal curve over the mirror distance L in the Fabry -Erot interferometer 6.
  • This waveform is shown in FIG.
  • the waveform recorded in the frequency comb scan by continuously varying the mirror distance L of the Fabry-Perot interferometer 6 is shown in a pixel 23a of the CCD camera 23, which results by summing all the spectral components which could pass through the confocal aperture 21.
  • the optical path difference x_O 200 microns and the spectral range with enveloping Gaussian profile is between 1300 nm and 1800 nm.
  • the chromatic confinement of the spectrum by confocal discrimination is therefore low here, since the chromatic depth splitting is also low here.
  • the signals become smaller and smaller in the half-width, becoming narrower and less intense.
  • the distance of the modulated signals to each other also becomes smaller and smaller with increasing n.
  • the absolute order of these signal profiles can be determined by means of a comparatively simple system of equations via the changes ⁇ l_ 2-3 and ⁇ L 3-4, shown in FIG. 9, usually by means of a linear system of equations. be determined.
  • optical Path difference x_O in the object-imaging interferometer for each optically detected object element.
  • the distance or the depth of an object element P can then be calculated at least approximately from this optical path difference x_O, even if the refractive index in the object space is at least approximately known.
  • FIG. 14 shows an optical arrangement with chromatic properties in the object beam path and achromatic properties for the reference beam path.
  • the application is provided for macroscopic objects 19 at about one meter from the optical measuring system.
  • a tunable frequency comb laser 1 b having a delay length of Y is arranged.
  • the delay length Y is definably changed by +/- ⁇ Y in the resonator of the frequency comb laser 1 b by driver modules of the electronic system 26.
  • the frequency comb laser 1b is followed by an optical isolator, not shown here.
  • the light of this frequency comb laser 1b is coupled by means of focusing optics 2 in a single-mode fiber 3, exits from this at the output 4 of the singlemode fiber 3 again and is collimated by a lens 5.
  • the light passes through a beam splitter 9 and reaches a microlens array 10 with microlenses 11. Foci are formed. These are imaged by the lens 12 to infinity.
  • the light passes in the focal plane of the objective 12 a diffractive zone lens 13 with a light-diffusing effect, which is designed as a phase grating.
  • zeros in the zeroth order which function as reference beams R_0, and beams in the first order O_1 ⁇ are formed, these beams representing chromatic-depth split, discretized bundles of objects.
  • a refractive surface 16 In the optical system 15 is a refractive surface 16, wherein this refractive surface 16 also represents the reference surface in the two-beam interferometer.
  • the objective 12, the diffractive zone lens 13, a diffusing lens 24 and the refractive surface 16 together form a chromatic imaging system 15.
  • the reference beams R_0, which have arisen in the zeroth diffraction order after the diffractive zone lens 13, are applied to the refractive surface 16 sharply focused, creating a relatively small field of foci there.
  • On the refractive surface 16 is a beam splitter layer 17 with a relatively low reflectance.
  • the diverging lens 24 thus serves to increase the distance between the focus chain 18 produced by chromatic splitting and the measurement of a macroscopic field.
  • the 15 shows the intensity wavelet resulting on the pixel 23a of the CCD camera 23 during the Y-scan of the tunable frequency comb laser 1b. From this intensity wavelet, in the presence of an object element in the depth measuring range, the maximum of the envelope can be determined by means of suitable and known evaluation algorithms by a computer in order to calculate the depth position of each detectable object element of the object 19.
  • FIG. 16 shows a device or arrangement which is suitable above all for microscopic or mesoscopic application with a tunable frequency comb laser 1b having a delay length with a mean value of Y, variable in the resonator by +/- ⁇ Y.
  • the tunable frequency comb laser 1 b is tuned in a long scan. The course over time is shown in FIG. 17.
  • the light of this frequency comb laser 1 b in FIG. 16 is coupled into a singlemode fiber 3 by means of focusing optics 2, emerges therefrom again at the output 4 of the singlemode fiber 3 and is collimated by an objective 5.
  • the light passes through a beam splitter 9 and reaches a pinhole array 110 with pinholes 111. These pinholes 111 are imaged by the objective 12 to infinity.
  • the light passes in the focal plane of the objective 12 a diffractive zone lens 13 with a light-diffusing effect, which is designed as a phase grating.
  • a diffractive zone lens 13 with a light-diffusing effect, which is designed as a phase grating.
  • zeroth-order beams which act as reference beams R_0 and beams in the first order O_1 ⁇ , these beams representing chromatic-depth split, discretized object beams.
  • the objective 12, the diffractive zone lens 13 and the objective 14a for focusing together form a chromatic imaging system 15.
  • the reference beams R_0 which have arisen in the zeroth diffraction order after the diffractive zone lens 13, are applied to the refractive surface 16a on the plane-parallel plate 116 by means of an objective 14a sharply focused, creating a relatively small field of foci there.
  • this refractive surface 16 at the same time also the reference surface in the two-beam interferometer, here a Fizeau interferometer, is.
  • a beam splitter layer 17 On the refractive surface 16a of the plane parallel plate 116 is a beam splitter layer 17 with comparatively low reflectance.
  • the reference beams R_0 are reflected back into the sensor after reflection at the beam splitter layer 17.
  • the bundles in the first order O_1 ⁇ reach the object space, where the stationary object 19 is located, which is hit exactly or at least approximately in each object element by one of the focuses of the focus chain 18.
  • the backscattered from the surface of the object 19 light all bundles in the order O_1 ⁇ passes the plane parallel plate 116 and passes through the lens 14a again to the diffractive zone lens 13.
  • the plane-parallel plate 116 performs in the measuring process by means of piezoelectric actuator 25a several axial short scans in a sawtooth shape, which are synchronized in the duration of the short scan .DELTA.t_kurz_lnt for long scan of the frequency comb laser 1 b and read the CCD camera 23, so that in the duration of the short scan ⁇ t_kurz_lnt both the delay length Y of the frequency comb. Increase the laser 1 b as well as the optical retardation x_O in the Fizeau interferometer by the same amount. The temporal relationship is shown in FIG.
  • the synchronization, control and electrical drive of frequency comb laser 1 b, piezo actuator 25 a and CCD camera 23 via the not shown electronic modules of the electronic system 26 for system control, which also includes a computer, which also includes the evaluation of the camera signals takes over.
  • the amount of magnification here corresponds to the centroid wavelength ⁇ _S.
  • the change in the phase angle in the duration of the short scan ⁇ t_kurz_lnt is thus at least approximately zero and in this time duration ⁇ t_kurz_lnt an image is recorded by means of a CCD camera 23.
  • FIG. 20 shows an approach for the measurement of microscopically small objects 19 with a comparatively large numerical aperture and thus smaller Therefore, with a depth extension of the object 19, greater than the wavelength of the optical depth of field, it is necessary to perform a depth scan in order to be able to image all the object details once in the serial measuring process.
  • the temporal relationship is shown in FIG. This oscillation is a short scan.
  • the light of the frequency comb laser 1 b is coupled by means of focusing optics 2 in a single-mode fiber 3, exits from this at the output 4 of the singlemode fiber 3 again, by means of lens 124 to a rotating Mattture 105 steered, where a field is illuminated on this.
  • This luminous field is imaged by a lens 5 in the pupil of the mirror lens 127.
  • the light is incident on a beam splitter 109, which has a beam splitter layer 109a and a beam splitter layer 109b and belongs to an object imaging two-beam interferometer.
  • the light reflected at the beam splitter layer 109a passes back through the triple reflector 126 in the beam splitter 109 and now passes through the beam splitter layer 109b and passes through the lens 22 on the CCD camera 23.
  • the light passing through the beam splitter layer 109a then passes through the mirror lens 127 and passes on the object 19, which is moved in the measuring process in depth. The temporal relationship is made visible in FIG.
  • each object element of the object 19 is once imaged in a wave-optical manner onto the CCD camera 23 by reflecting the backscattered light after passing through the mirror objective 127 at the beam splitter layer 109b and imaging it onto the CCD camera 23 via the objective 22 ,
  • the CCD camera 23 records a stack of images during the measuring process, the image recording frequency here being 400 Hz.
  • the half-width of the spectrum of the used light of the frequency comb laser 1b is about 200 nm.
  • the object-imaging two-beam interferometer in FIG. 20 has, on average, an optical path difference x_O of 95 mm, which corresponds to the mean optical delay length Y of the frequency comb laser 1b.
  • the object 19 is moved in the measuring process with a speed of 172.2 microns / s in the depth.
  • the phase angle ⁇ in the interference image on the CCD camera 23 practically does not change in every fourth camera image, namely, when the retardation length Y and the optical retardation x_O increase by at least approximately the same amount, respectively, and the interference image becomes almost nearly every fourth camera image quiet.
  • An image is always stored here when the oscillation process of the frequency comb laser 1b is in the rise range Ai-2, Ai-1, Ai ....
  • the change of the phase angle in the pixels is approximately 756 degrees from a first image to a fifth image, each in the phase of a rise range Ai-2, Ai-2, Ai. This leads to a subsampling of the interference signals and provides over the depth scan of the object 19 in the pixels of the CCD camera 23 for each detected object point in each case a comparatively low-frequency wavelet.
  • the triple reflector 126 and the lens 127 are each as mirror systems educated.
  • the dispersion in the beam splitter plate 109 which is formed as a high-precision plane-parallel plate is the same in the two arms of the object-imaging interferometer, so that a nearly complete compensation of the dispersion in the object-imaging interferometer is given and advantageously no disturbing chirp effect occurs in the interference signal.
  • Another advantage of this arrangement is that no mechanical vibrations due to short scans can occur in the object-imaging interferometer, since these take place in the frequency comb laser 1b arranged spatially remote from the object-imaging interferometer.
  • Figure 24 illustrates the magnification of the optical retardation x_O versus the time of an interferometer long scan when, as shown in Figure 22, the object 19 in Figure 20 is advanced in depth in a long scan at a constant speed.
  • the dotted line also shows the difference between the optical path difference x_O and the delay length Y of the frequency comb laser 1b over time.
  • the increase of this difference that is, x_O -Y, is significantly reduced, and in these times of short scans, the CCD camera 23 is read out each time with the integration period ⁇ tD.
  • the increase in the optical retardation is 2.1 centroid wavelengths ⁇ _S.
  • the phase angle ⁇ interference is also modulated. This results in a variable change of the phase angular velocity d ⁇ / dt over time.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

L'invention concerne un procédé et un dispositif d'interférométrie confocale modulable pour la mesure de distance, la détection en 3D d'un objet, la tomographie en cohérence optique avec un interféromètre reproducteur d'objet et au moins une source lumineuse. L'interféromètre présente sur chaque élément objet optiquement détecté une différence de trajet différente de zéro. C'est ainsi que les maxima d'une ondelette de fréquence sinusoïdale, appartenant à chaque élément objet détecté, présente un écart de fréquence ?f_Objekt. Au moins un détecteur à trame, à détection spectrale intégrale, est prévu pour capter l'objet. La source lumineuse est de préférence conçue avec un peigne de fréquence et les écarts du peigne de fréquence ?f_Quelle sont modifiés lors de la mesure de manière prédéterminée dans le temps dans le cadre d'un balayage. Les écarts de fréquence ?f_Quelle sont rendus au moins une fois égaux à l'écart de fréquence ?f_Objekt ou égaux à un multiple entier des écarts de fréquences ?f_Objekt pour chaque élément objet. Cela peut également être effectué par un balayage dans l'interféromètre reproduisant d'objet. Lors du balayage, une modulation de la courbe du signal est générée et détectée séquentiellement au moyen du détecteur à trame. La valeur effective des écarts du peigne de fréquence ?f_Quelle dans cette courbe du signal, par exemple au maximum de la modulation, est déterminée et sert ultérieurement au calcul de la différence de trajet optique associée d'un élément objet détecté. Des distances d'éléments objets ou des changements des longueurs d'onde optique, par exemple pour un micro-objet biologique, sont déterminées par imagerie sur cette base, dans le cadre d'un processus.
EP09741220A 2008-10-10 2009-10-12 Procédé et dispositif d'interférométrie Withdrawn EP2347215A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102008052003 2008-10-10
DE102008052814 2008-10-14
DE102008062879A DE102008062879B4 (de) 2008-10-10 2008-12-15 Verfahren und Anordnung zur skalierbaren Interferometrie
PCT/EP2009/007327 WO2010040570A1 (fr) 2008-10-10 2009-10-12 Procédé et dispositif d'interférométrie

Publications (1)

Publication Number Publication Date
EP2347215A1 true EP2347215A1 (fr) 2011-07-27

Family

ID=42096540

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09741220A Withdrawn EP2347215A1 (fr) 2008-10-10 2009-10-12 Procédé et dispositif d'interférométrie

Country Status (4)

Country Link
US (1) US8605289B2 (fr)
EP (1) EP2347215A1 (fr)
DE (1) DE102008062879B4 (fr)
WO (1) WO2010040570A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109073368A (zh) * 2016-03-25 2018-12-21 Fogale 纳米技术公司 用于晶片等对象的2d/3d检测的色差共焦装置和方法

Families Citing this family (105)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8292617B2 (en) 2009-03-19 2012-10-23 Align Technology, Inc. Dental wire attachment
US8765031B2 (en) 2009-08-13 2014-07-01 Align Technology, Inc. Method of forming a dental appliance
DE102010006237A1 (de) * 2010-01-26 2011-07-28 Siemens Aktiengesellschaft, 80333 Verfahren und Anordnung zum Messen der Dicke einer Schicht
US8970671B2 (en) 2010-02-23 2015-03-03 California Institute Of Technology Nondiffracting beam detection devices for three-dimensional imaging
US9211166B2 (en) 2010-04-30 2015-12-15 Align Technology, Inc. Individualized orthodontic treatment index
US9241774B2 (en) 2010-04-30 2016-01-26 Align Technology, Inc. Patterned dental positioning appliance
DE102010046907B4 (de) 2010-08-16 2013-01-31 Universität Stuttgart Robustes One-Shot-Interferometer und Verfahren , insbesondere auch als Scout-Sensor zur multi-sensoriellen Materialmessung oder Tumorzellen-Erkennung
US9763758B2 (en) 2011-01-13 2017-09-19 Align Technology, Inc. Virtual and physical dental models of dental surfaces and analog socket structure of a dental implant and related procedures
WO2012103233A1 (fr) * 2011-01-25 2012-08-02 Massachusetts Institute Of Technology Microscopie plein champ à phase de réflexion à prise unique
CN102175426B (zh) * 2011-02-15 2013-05-22 北京理工大学 共焦干涉定焦及曲率半径测量方法
US9086536B2 (en) 2011-03-09 2015-07-21 California Institute Of Technology Talbot imaging devices and systems
US8946619B2 (en) * 2011-04-20 2015-02-03 California Institute Of Technology Talbot-illuminated imaging devices, systems, and methods for focal plane tuning
US9403238B2 (en) 2011-09-21 2016-08-02 Align Technology, Inc. Laser cutting
US9375300B2 (en) 2012-02-02 2016-06-28 Align Technology, Inc. Identifying forces on a tooth
US9220580B2 (en) 2012-03-01 2015-12-29 Align Technology, Inc. Determining a dental treatment difficulty
US9414897B2 (en) 2012-05-22 2016-08-16 Align Technology, Inc. Adjustment of tooth position in a virtual dental model
FI125762B (en) * 2012-10-11 2016-02-15 Teknologian Tutkimuskeskus Vtt Oy Method for determining calibration parameters for a spectrometer
US9513164B2 (en) * 2013-03-15 2016-12-06 Honeywell International Inc. Stand-off spectrometry systems and methods
JP5915874B2 (ja) 2013-12-19 2016-05-11 横河電機株式会社 顕微鏡装置
FR3015659B1 (fr) * 2013-12-20 2016-01-29 Centre Nat Rech Scient Appareil et procede de tomographie optique
WO2015109274A1 (fr) 2014-01-18 2015-07-23 Daylight Solutions, Inc. Système d'imagerie spectroscopique à faible bruit
US10437033B2 (en) * 2014-01-18 2019-10-08 Daylight Solutions, Inc. Modulating spectroscopic imaging system using substantially coherent illumination
US11803044B2 (en) 2014-01-18 2023-10-31 Daylight Solutions, Inc. Low-noise spectroscopic imaging system with steerable substantially coherent illumination
JP6172465B2 (ja) * 2014-01-23 2017-08-02 株式会社東京精密 ステージの位置制御装置及び方法
JP2015137996A (ja) * 2014-01-24 2015-07-30 株式会社東京精密 計測システム、ファブリーペロー共振器及び計測方法
WO2015183994A1 (fr) 2014-05-28 2015-12-03 Santec Corporation Mesure optique non-invasive d'analyte sanguin
US10772506B2 (en) * 2014-07-07 2020-09-15 Align Technology, Inc. Apparatus for dental confocal imaging
US9693839B2 (en) 2014-07-17 2017-07-04 Align Technology, Inc. Probe head and apparatus for intraoral confocal imaging using polarization-retarding coatings
US9675430B2 (en) 2014-08-15 2017-06-13 Align Technology, Inc. Confocal imaging apparatus with curved focal surface
JP6836048B2 (ja) * 2014-08-27 2021-02-24 国立大学法人電気通信大学 距離測定装置
JP6895192B2 (ja) * 2014-08-27 2021-06-30 国立大学法人電気通信大学 距離測定装置
US10449016B2 (en) 2014-09-19 2019-10-22 Align Technology, Inc. Arch adjustment appliance
US9610141B2 (en) 2014-09-19 2017-04-04 Align Technology, Inc. Arch expanding appliance
US9744001B2 (en) 2014-11-13 2017-08-29 Align Technology, Inc. Dental appliance with cavity for an unerupted or erupting tooth
US10504386B2 (en) 2015-01-27 2019-12-10 Align Technology, Inc. Training method and system for oral-cavity-imaging-and-modeling equipment
US9970819B2 (en) * 2015-03-23 2018-05-15 Si-Ware Systems High performance parallel spectrometer device
US10548520B2 (en) 2015-04-01 2020-02-04 Santec Corporation Non-invasive optical measurement of blood analyte
US10698111B2 (en) * 2015-05-15 2020-06-30 Sikorsky Aircraft Corporation Adaptive point cloud window selection
JP6713149B2 (ja) 2015-06-01 2020-06-24 サンテック株式会社 ２つの波長を合成する光コヒーレンストモグラフィーシステム
US10248883B2 (en) 2015-08-20 2019-04-02 Align Technology, Inc. Photograph-based assessment of dental treatments and procedures
JP6628030B2 (ja) * 2015-10-22 2020-01-08 株式会社東京精密 距離測定装置及びその方法
US11931222B2 (en) 2015-11-12 2024-03-19 Align Technology, Inc. Dental attachment formation structures
US11554000B2 (en) 2015-11-12 2023-01-17 Align Technology, Inc. Dental attachment formation structure
CN105547144B (zh) * 2015-11-30 2019-02-05 哈尔滨工业大学 一种超分辨结构探测阵列共焦相干成像装置及其成像方法
CN105547145B (zh) * 2015-11-30 2019-02-05 哈尔滨工业大学 一种超分辨结构探测共焦相干成像装置及其成像方法
US11103330B2 (en) 2015-12-09 2021-08-31 Align Technology, Inc. Dental attachment placement structure
US11596502B2 (en) 2015-12-09 2023-03-07 Align Technology, Inc. Dental attachment placement structure
US10724945B2 (en) * 2016-04-19 2020-07-28 Cascade Technologies Holdings Limited Laser detection system and method
US10677580B2 (en) 2016-04-27 2020-06-09 Santec Corporation Optical coherence tomography system using polarization switching
JP6797564B2 (ja) * 2016-06-01 2020-12-09 オリンパス株式会社 位相物体可視化装置、位相物体可視化方法
EP3471653B1 (fr) 2016-06-17 2021-12-22 Align Technology, Inc. Dispositif de surveillance de performances d'un appareil orthodontique
US10470847B2 (en) 2016-06-17 2019-11-12 Align Technology, Inc. Intraoral appliances with sensing
US9993153B2 (en) 2016-07-06 2018-06-12 Santec Corporation Optical coherence tomography system and method with multiple apertures
CN208942463U (zh) 2016-07-27 2019-06-07 阿莱恩技术有限公司 口内扫描系统和口内扫描装置
US10507087B2 (en) 2016-07-27 2019-12-17 Align Technology, Inc. Methods and apparatuses for forming a three-dimensional volumetric model of a subject's teeth
DE102016115827A1 (de) * 2016-08-25 2018-03-01 Nanofocus Ag Verfahren und Vorrichtung zur optischen Oberflächenmessung mit Hilfe eines chromatisch konfokalen Sensors
US10317344B2 (en) * 2016-09-07 2019-06-11 Kla-Tencor Corporation Speed enhancement of chromatic confocal metrology
CN109922754B (zh) 2016-11-04 2021-10-01 阿莱恩技术有限公司 用于牙齿图像的方法和装置
EP3547950A1 (fr) 2016-12-02 2019-10-09 Align Technology, Inc. Procédés et appareils pour personnaliser des dispositifs d'expansion palatine rapides à l'aide de modèles numériques
WO2018102702A1 (fr) 2016-12-02 2018-06-07 Align Technology, Inc. Caractéristiques d'un appareil dentaire permettant l'amélioration de la parole
US11376101B2 (en) 2016-12-02 2022-07-05 Align Technology, Inc. Force control, stop mechanism, regulating structure of removable arch adjustment appliance
WO2018102809A1 (fr) 2016-12-02 2018-06-07 Align Technology, Inc. Appareils d'expansion palatine et méthodes d'expansion de palais
US10548700B2 (en) 2016-12-16 2020-02-04 Align Technology, Inc. Dental appliance etch template
US10456043B2 (en) 2017-01-12 2019-10-29 Align Technology, Inc. Compact confocal dental scanning apparatus
GB201700905D0 (en) 2017-01-19 2017-03-08 Cascade Tech Holdings Ltd Close-Coupled Analyser
US10779718B2 (en) 2017-02-13 2020-09-22 Align Technology, Inc. Cheek retractor and mobile device holder
US10613515B2 (en) 2017-03-31 2020-04-07 Align Technology, Inc. Orthodontic appliances including at least partially un-erupted teeth and method of forming them
US10426337B2 (en) 2017-06-01 2019-10-01 Santec Corporation Flow imaging in an optical coherence tomography (OCT) system
US11045283B2 (en) 2017-06-09 2021-06-29 Align Technology, Inc. Palatal expander with skeletal anchorage devices
CN116942335A (zh) 2017-06-16 2023-10-27 阿莱恩技术有限公司 牙齿类型和萌出状态的自动检测
US10408600B2 (en) * 2017-06-22 2019-09-10 Santec Corporation Optical coherence tomography with a fizeau-type interferometer
WO2019005808A1 (fr) 2017-06-26 2019-01-03 Align Technology, Inc. Indicateur de performance de biocapteur pour appareils intrabuccaux
CN107240854B (zh) * 2017-07-07 2019-04-09 浙江理工大学 基于欠采样的激光频率锁定至光频梳方法及装置
JP6341325B2 (ja) * 2017-07-07 2018-06-13 株式会社東京精密 ステージの位置制御装置
US10206567B2 (en) 2017-07-12 2019-02-19 Santec Corporation Dual wavelength resampling system and method
US10885521B2 (en) 2017-07-17 2021-01-05 Align Technology, Inc. Method and apparatuses for interactive ordering of dental aligners
WO2019018784A1 (fr) 2017-07-21 2019-01-24 Align Technology, Inc. Ancrage de contour palatin
US10517482B2 (en) 2017-07-27 2019-12-31 Align Technology, Inc. Optical coherence tomography for orthodontic aligners
CN115462921A (zh) 2017-07-27 2022-12-13 阿莱恩技术有限公司 牙齿着色、透明度和上釉
US11092424B2 (en) * 2017-08-02 2021-08-17 The Trustees Of Columbia University In The City Of New York Microresonator-frequency-comb-based platform for clinical high-resolution optical coherence tomography
US11116605B2 (en) 2017-08-15 2021-09-14 Align Technology, Inc. Buccal corridor assessment and computation
US11123156B2 (en) 2017-08-17 2021-09-21 Align Technology, Inc. Dental appliance compliance monitoring
US10813720B2 (en) 2017-10-05 2020-10-27 Align Technology, Inc. Interproximal reduction templates
WO2019084326A1 (fr) 2017-10-27 2019-05-02 Align Technology, Inc. Autres structures de réglage de morsure
US11576752B2 (en) 2017-10-31 2023-02-14 Align Technology, Inc. Dental appliance having selective occlusal loading and controlled intercuspation
CN111315315B (zh) 2017-11-01 2022-08-23 阿莱恩技术有限公司 自动治疗规划
US10502546B2 (en) 2017-11-07 2019-12-10 Santec Corporation Systems and methods for variable-range fourier domain imaging
WO2019100022A1 (fr) 2017-11-17 2019-05-23 Align Technology, Inc. Dispositifs de retenue orthodontiques
CN111417357B (zh) 2017-11-30 2022-07-26 阿莱恩技术有限公司 用于监测口腔矫治器的传感器
WO2019118876A1 (fr) 2017-12-15 2019-06-20 Align Technology, Inc. Méthodes et appareils de traitement orthodontique adaptatif à boucle fermée
US10980613B2 (en) 2017-12-29 2021-04-20 Align Technology, Inc. Augmented reality enhancements for dental practitioners
KR20200115580A (ko) 2018-01-26 2020-10-07 얼라인 테크널러지, 인크. 구강 내 진단 스캔 및 추적
WO2019157223A1 (fr) * 2018-02-07 2019-08-15 Arizona Board Of Regents On Behalf Of The University Of Arizona Spectroscopie et détection de molécule unique sans marqueur
US11213200B2 (en) 2018-03-22 2022-01-04 Santec Corporation Topographical imaging using combined sensing inputs
US11937991B2 (en) 2018-03-27 2024-03-26 Align Technology, Inc. Dental attachment placement structure
AU2019251474A1 (en) 2018-04-11 2020-10-29 Align Technology, Inc. Releasable palatal expanders
US11067671B2 (en) 2018-04-17 2021-07-20 Santec Corporation LIDAR sensing arrangements
US10838047B2 (en) 2018-04-17 2020-11-17 Santec Corporation Systems and methods for LIDAR scanning of an environment over a sweep of wavelengths
US10816325B2 (en) * 2018-08-06 2020-10-27 Government Of The United States Of America, As Represented By The Secretary Of Commerce Deformometer for determining deformation of an optical cavity optic
US11175224B2 (en) 2018-08-06 2021-11-16 Government Of The United States Of America, As Represented By The Secretary Of Commerce Optical refraction barometer
US11193752B2 (en) * 2018-09-05 2021-12-07 Cylite Pty Ltd Optical coherence tomography with dispersed structured illumination
CN109975246B (zh) * 2019-03-01 2021-08-24 中国科学院苏州生物医学工程技术研究所 大量程无接触光学间距测量系统及其测量方法
AU2020405254A1 (en) * 2019-12-20 2022-05-12 The General Hospital Corporation Systems, methods, and media for multiple beam optical coherence tomography
WO2023010174A1 (fr) * 2021-08-04 2023-02-09 Cylite Pty Ltd Imagerie optique de domaine spectral avec éclairage par peigne de longueur d'onde
WO2023163018A1 (fr) * 2022-02-24 2023-08-31 国立大学法人電気通信大学 Dispositif de mesure optique

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD240824A3 (de) 1972-01-04 1986-11-19 Johannes Schwider Verfahren und vorrichtung zur justierung von zwei ebenen zueinander
US4340306A (en) 1980-02-04 1982-07-20 Balasubramanian N Optical system for surface topography measurement
DE3623265C2 (de) 1986-07-10 1994-11-03 Siemens Ag Verfahren und Anordnung zur faseroptischen Messung einer Weglänge oder einer Weglängenänderung
DD282371A7 (de) * 1988-02-10 1990-09-12 Akad Wissenschaften Ddr Verfahren und anordnung zur messung der mikrogestalt technischer oberflaechen
DE4405450A1 (de) 1994-02-18 1995-08-24 Johannes Prof Dr Schwider Dispersives Interferometrisches Profilometer
GB2355210B (en) 1998-05-19 2003-03-19 Peter Robert Lynn A traction kite
JP3739987B2 (ja) * 2000-02-18 2006-01-25 財団法人神奈川科学技術アカデミー トモグラフィー装置
DE10321895B4 (de) * 2003-05-07 2010-09-16 Universität Stuttgart Sensor zur Erfassung der Topografie mit einem Zweistrahl-Interferometer
JP4543180B2 (ja) * 2004-08-18 2010-09-15 国立大学法人東京農工大学 形状測定方法、形状測定装置および周波数コム光発生装置
DE102004052205A1 (de) * 2004-10-20 2006-05-04 Universität Stuttgart Interferometrischer Multispektral-Sensor und interferometrisches Multispektral-Verfahren zur hochdynamischen Objekt-Tiefenabtastung oder Objekt-Profilerfassung
DE102005023212B4 (de) 2005-05-16 2007-07-12 Häusler, Gerd, Prof. Dr. Verfahren und Vorrichtung zur schnellen und genauen Weisslichtinterferometrie
US7391520B2 (en) 2005-07-01 2008-06-24 Carl Zeiss Meditec, Inc. Fourier domain optical coherence tomography employing a swept multi-wavelength laser and a multi-channel receiver
EP1913364B1 (fr) * 2005-07-28 2013-04-10 Bioptigen, Inc. Système d'imagérie à coherence optique présentant une largeur de ligne efficace reduite
DE102006007170B4 (de) * 2006-02-08 2009-06-10 Sirona Dental Systems Gmbh Verfahren und Anordnung zur schnellen und robusten chromatisch konfokalen 3D-Messtechnik

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2010040570A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109073368A (zh) * 2016-03-25 2018-12-21 Fogale 纳米技术公司 用于晶片等对象的2d/3d检测的色差共焦装置和方法
CN109073368B (zh) * 2016-03-25 2020-07-24 Fogale 纳米技术公司 用于晶片等对象的2d/3d检测的色差共焦装置和方法

Also Published As

Publication number Publication date
US20110235045A1 (en) 2011-09-29
DE102008062879A1 (de) 2010-05-12
US8605289B2 (en) 2013-12-10
DE102008062879B4 (de) 2010-10-28
WO2010040570A1 (fr) 2010-04-15

Similar Documents

Publication Publication Date Title
DE102008062879B4 (de) Verfahren und Anordnung zur skalierbaren Interferometrie
EP2843360B1 (fr) Interféromètre à mission unique robuste et procédé OCT, en particulier pour mesurer le matériau et également de détection de cellules tumorales
DE102008020902B4 (de) Anordnung und Verfahren zur konfokalen, spektralen Zweistrahl-Interferometrie
EP2526373B1 (fr) Procédé et agencement d'interférométrie robuste
DE4310209C2 (de) Optische stationäre Bildgebung in stark streuenden Medien
EP1805477B1 (fr) Ensemble et procede interferometrique
EP2877810B1 (fr) Dispositif de mesure de distance interférométrique et procédé associé
EP1272812B1 (fr) Dispositif de mesure interferometrique
WO2013171309A1 (fr) Microscope optique et procédé de prise de vues au moyen d'un microscope optique
DE102011016660B4 (de) Verfahren und Anordnung zur Kurz-Kohärenz-Holografie
EP1984770A1 (fr) Procédé et dispositif conçus pour une technique confocale chromatique de mesure 3d rapide et robuste
DE102016014802B4 (de) Anordnung und Verfahren zur robusten Zweistrahl-Interferometrie mit einer Dreifach-Reflexions-Anordnung
DE10392881B4 (de) Frequenzabtast-Interferometer mit diffus-reflektierender Referenzoberfläche
DE10392828T5 (de) Interferometrieverfahren und -systeme mit gekoppelter Hohlraumgeometrie zur Verwendung mit einer erweiterten Quelle
DE102005006724A1 (de) Verfahren und Anordung zur konfokalen Spektral-Interferometrie, insbesondere auch zur optischen Kohärenz-Tomografie (OCT)und/oder optischen Kohärenz-Mikroskopie (OCM)von biologischen und technischen Objekten
WO2007079811A1 (fr) Procédé et dispositif de mesure optique de la distance
DE102010006239B3 (de) Verfahren und Anordnung zur robusten Interferometrie
DE102004052205A1 (de) Interferometrischer Multispektral-Sensor und interferometrisches Multispektral-Verfahren zur hochdynamischen Objekt-Tiefenabtastung oder Objekt-Profilerfassung
DE102005042733B3 (de) Verfahren und Anordnung zur Spektral-Interferometrie mit chromatischer Tiefenaufspaltung, insbesondere auch Mirau-Interferometer
EP1311801B1 (fr) Dispositif de mesure de forme interferometrique a faible coherence pour plusieurs surfaces (siege de soupape) a travers plusieurs plans de reference
DE102006007573B4 (de) Verfahren und Vorrichtung zur 3D-Geometrieerfassung von Objektoberflächen
EP1314953A2 (fr) Interféromètre et procédé de mesure interférométrique
DE10131779B4 (de) Interferometrische Messvorrichtung
EP1210564B1 (fr) Dispositif de mesure interferometrique
DE10321886A1 (de) Robuster interferometrischer Sensor und Verfahren zur Objektabtastung

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20110510

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

AX Request for extension of the european patent

Extension state: AL BA RS

DAX Request for extension of the european patent (deleted)
17Q First examination report despatched

Effective date: 20131011

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20160914