EP2235503A1 - Dispositif pour déterminer le degré de réflexion d'un échantillon - Google Patents

Dispositif pour déterminer le degré de réflexion d'un échantillon

Info

Publication number
EP2235503A1
EP2235503A1 EP08862939A EP08862939A EP2235503A1 EP 2235503 A1 EP2235503 A1 EP 2235503A1 EP 08862939 A EP08862939 A EP 08862939A EP 08862939 A EP08862939 A EP 08862939A EP 2235503 A1 EP2235503 A1 EP 2235503A1
Authority
EP
European Patent Office
Prior art keywords
light
measuring
intensity
white
arrangement according
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Withdrawn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
EP08862939A
Other languages
German (de)
English (en)
Inventor
Nico Correns
Werner Hoyme
Felix Kerstan
Thomas Keune
Wilhelm Schebesta
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.)
Carl Zeiss Microscopy GmbH
Original Assignee
Carl Zeiss MicroImaging GmbH
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 Carl Zeiss MicroImaging GmbH filed Critical Carl Zeiss MicroImaging GmbH
Publication of EP2235503A1 publication Critical patent/EP2235503A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
    • G01N21/274—Calibration, base line adjustment, drift correction
    • G01N21/276—Calibration, base line adjustment, drift correction with alternation of sample and standard in optical path
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
    • G01N21/474—Details of optical heads therefor, e.g. using optical fibres
    • G01N2021/4742—Details of optical heads therefor, e.g. using optical fibres comprising optical fibres

Definitions

  • the invention relates to an arrangement for measuring the reflectance of the direct or scattered reflection of a sample, with a light source for separate illumination of the sample on the one hand and of comparison surfaces on the other hand, as well as with an evaluation circuit for computational linkage of the determined from the comparison surfaces intensity values to the reflectance.
  • Arrangements for determining the reflectance of sample surfaces are known in the prior art in which a white standard area and a black standard area are used as comparison areas. In each case at the beginning of the measurements, a measuring scale is determined with these two standards and the measuring instrument is calibrated with this scale. Between the two standard values formed by the white standard and the black standard, both measured at the same place as the sample, the reflectance determined by the sample surface is arranged.
  • the system parameters change because, for example, the intensity of the light source decreases or the sensitivity of sensors used for the optoelectronic conversion of received signals changes. To compensate for these changes, recalibrating the scale is required for repeated measurements.
  • the sample is removed from the sample plane, in its place first the white standard area and then the black standard area or vice versa positioned and thus redefined the measuring scale.
  • This procedure can only be used in the laboratory because of the relatively large time required for the calibration. In the process measuring, however, these interruptions are annoying and in many cases not possible.
  • measuring processes must also be interrupted for the swiveling in and out of the white and black areas and thus can not run continuously.
  • the invention has the object, an arrangement of the type mentioned in such a way that a more efficient determination of the reflectance of samples or sample surfaces is guaranteed than in the prior art.
  • This object is achieved with an arrangement comprising: a) a light source for separate illumination of both a white surface and a measuring surface, wherein
  • a white standard, a black standard and the sample surface are provided for the embodiment of the measuring surface, and
  • the white surface is formed diffusely reflecting, and the light source, the white surface and the means for intensity measurement are enclosed on all sides by the housing of a measuring head, whereas the measuring surface is arranged outside the measuring head.
  • the housing of the measuring head has an area which is transparent to the light emanating from the light source and to the light reflected from the measuring area. Because of the integration of the white surface in the housing enclosed by the measuring head is below also the term internal white area used.
  • At least one optoelectronic transducer is provided as a means for measuring the intensity, which is referred to hereinafter as a detector in connection with the invention described herein, and are optical fibers each with upstream coupling optics for detecting and transmitting light which is reflected at the internal white area, and of light reflected at the measuring surface to the detector.
  • a plurality of coupling-in optics with a downstream optical waveguide are arranged radially symmetrically with respect to the measuring surface for detecting light reflected at the measuring surface.
  • a first shutter is arranged in the transmission path of the light which is reflected from the measuring surface and passes to the detector, and a second shutter is arranged in the transmission path of the light which is reflected by the internal white surface and reaches the detector.
  • the two shutters are provided for blocking or release of the respective transmission path and designed accordingly.
  • the measurement of intensity values depending on the blocking or release of the transmission paths is provided as follows:
  • Ip the intensity of the light reflected from the sample.
  • the first white standard area is inclined to the direction of propagation of the light reflected by the measuring area in such a way that this light does not strike the internal white area. This ensures that the result of the measurement of the intensity I w of light reflected from the internal white surface can not be falsified by light reflected from the measurement surface.
  • the internal white surface is of annular design and a plurality of coupling optics are positioned on a centrally arranged circumference, which are each connected via optical waveguides and a shutter to a detector, the detectors are sensitive to different wavelength ranges.
  • the arrangement according to the invention for an extremely broad wavelength range of the illuminating light directed at a sample.
  • three detectors may be provided, one of which is sensitive to the visible light wavelength range (VIS), a second to the near infrared wavelength range (NIR) and the third to the ultraviolet light wavelength range (UV).
  • VIS visible light wavelength range
  • NIR near infrared wavelength range
  • UV ultraviolet light wavelength range
  • a light source which emits light with a spectral-isotropic intensity distribution.
  • This can be formed, for example, as a reflector lamp.
  • the detector may be designed as a photodiode and the evaluation circuit for registering and linking integral intensity values.
  • the detector is part of a spectrometer and a having spatially resolving receiving surface.
  • the spectrometer can be equipped with two light entry gaps, wherein the transmission of light reflected at the internal white surface to a first entrance slit of the spectrometer and the transmission of light reflected at the measuring surface to the other entrance slit of the spectrometer.
  • the light incident through the two entrance slits is directed onto the receiving surface, and the evaluation circuit is designed to register and link spectrally resolved intensity values.
  • the spatial beam intensity distribution for example, a reflector lamp is exploited in such a way that the axial and radial dependencies on the sample or sample surface resulting irradiance in the largest possible range of the working distance, that is the distance between the light source and the measuring surface, each other compensate, and so a reflection measured value is obtained, which is largely independent of the working distance.
  • Fig.l is an illustration of the basic structure of the inventive arrangement
  • FIG. 2 shows a plan view of the arrangement according to Fig.l
  • FIG. 4 shows an example of the arrangement of a shutter in a realized by means of optical waveguide transmission path of the measuring or reference light to the spectrometer
  • FIG. 6 shows a timing diagram for some measured quantities to illustrate the principle of internal referencing.
  • Fig.l shows a built-in a measuring head 1 reflector lamp 2, of which a first radiation component 3 is directed through a Meßkopf needs 4 on a sample holder 5.
  • the sample holder 5 is provided and designed to receive a white standard 6, a black standard 7 and a sample 8 for which the reflectance R P is to be determined.
  • White standard 6, black standard 7 and sample 8 can be positioned on the sample holder 5 and are interchangeable there in a given sequence.
  • a second radiation component 9 of the light coming from the reflector lamp 2 is directed to a scattered reflective surface designed as a measuring standard of another white standard, referred to below as an internal white surface 10.
  • optical waveguide 11, 12, 13 and 14 are provided within the measuring head.
  • the optical waveguide 11 is preceded by a coupling-in optical system 15 which is positioned so that it receives the radiation reflected by the internal white surface 10 and couples it into the optical waveguide 11.
  • the light coupled into the optical waveguide 11 by means of the coupling optical system 15 passes to the light entry side of a shutter 16, the light exit side of which is optically connected to the optical waveguide 12.
  • the optical waveguide 12 is in communication with a first entrance slit 17 of a spectrometer 18.
  • the optical waveguide 13 is preceded by a coupling optics 19, which is provided for collecting light and is formed, which is reflected by a measuring surface, either from the located on the sample holder 5 white standard 6, black standard 7 or the surface of the sample 8 and by the Meßkopf mitogen 4 enters the measuring head 1 inside.
  • the coupled from the coupling optics 19 in the optical waveguide 13 light is propagated within the optical waveguide 13 to the light entrance side of a shutter 20 and passes from the light exit side of the shutter 20 in the optical waveguide 14.
  • the optical waveguide 14 terminates in a second entrance slit 21 of the spectrometer 18th
  • the coupling optics 15, optical fibers 11, shutter 16 and optical fibers 12 form a transmission path for light to the spectrometer 18, which is reflected by the internal white surface 10
  • the coupling optics 19, the optical waveguide 13, the shutter 12 and the optical waveguide 14 form a transmission path for reflected light from the measuring surface to the spectrometer 18th
  • the spatially resolving receiving surface 22 of a detector to which both the spectrum of light entering through the entrance slit 17 and the spectrum of the light entering through the entrance slit 21 strikes.
  • the signal outputs of the receiving surface 22 and the control inputs of the shutters 16 and 20 are in communication with an evaluation circuit (not shown in the drawing) for registering intensity values for light reflected at the internal white area 10 and at the measurement area, i. is formed on the white standard 6, on the black standard 7 or on the sample 8 reflected light and the mathematical combination of these intensity values.
  • the measurement of the intensity values is carried out as a function of the blocking or release of the transmission paths as follows, wherein in the exemplary embodiment of spectrally measured, dependent on the wavelength intensities is to be assumed:
  • Ip the intensity of the light reflected from the sample 8.
  • I W I- (R F + R W. [ ⁇ - R F ] 2 ) + I D
  • I S I- (R F + R S - [IR F ] 2 ) + I D
  • I P I- (R F + R P - [ ⁇ - R F ] 2 ) + I D
  • R N reflectance of white standard 6
  • R Wl reflectance of internal white 10
  • R 3 reflectance of black standard 7
  • Rp reflectance of the sample 8
  • an output calibration is first carried out based on the measurement surface as used in a predetermined sequence white standard 6 and black standards 7 by the intensity values I w, I Wl, s are measured I 0 and I.
  • the intensity values at time t ⁇ of the output calibration are calculated together as follows:
  • the intensity I 0 of the unlit detector surface is calculated out of the measured intensities I w , Is and I Wl .
  • the calculated differences D ws , D 5 and D Wl o are retained until the next external calibration.
  • the output calibration is successfully completed when the intensities remitted by the corresponding external standards 6 and 7 and by the internal white area 10 have been measured as intensity values I W1 , I D , Is and I w with the integration time it.
  • an internal referencing for the purpose of recalibration is carried out at predetermined time intervals ⁇ t in order to compensate for the change in system parameters and thereby obtain the long-term stability.
  • the quotient display is updated.
  • the reflectance R P (t) of the sample 8 or sample surface at time t results from the quotient of the measured values Q (t) and the certified values of the white or black standards R w and Rs used in the initial calibration:
  • the measured reflectivities Rp (t) are then valid only with respect to the specific instances of the standards R w and R s and not independent of them.
  • FIG. 6 shows by way of example a time diagram for a few values.
  • the internal white surface 10 is formed annularly on the inside of a truncated cone, which is centered to the propagation direction of the reflector lamp 2 for measuring head window 4 or to the sample holder 5 is directed. This can be seen in connection with Figure 2, a plan view in the direction D from Fig.l on the truncated cone.
  • FIG. 2 further shows a circumference 24 arranged concentrically thereon, on which - optionally in a special embodiment of the arrangement according to the invention - in addition to the already described coupling optics 15 and 19, to the optical waveguides 11, 12, 13, 14, to the shutters 16 and 20 and to the spectrometer 18 further, not provided with separate reference numerals coupling optical waveguide and shutter and connected in the same manner as already described with spectrometers, the additional spectrometers are sensitive to different wavelength ranges.
  • FIG. 3 a likewise advantageous embodiment of the arrangement according to the invention.
  • This embodiment has the purpose of exploiting the spatial beam intensity distribution of the reflector lamp 2 used here, for example, in such a way that compensate the axial and radial dependencies of the irradiation intensity resulting on the surface of the sample 8 in the largest possible range of the working distance z and so the to be determined reflection measurement R P from the working distance z is largely independent.
  • Angle ⁇ > 4 °, where the apex of the angle ⁇ is at z 100 mm.
  • FIG. 4 An integration of the shutter 16, 20 in the optical waveguide 11, 12 and 13, 14 is shown in Figure 4 by way of example with reference to the shutter 16.
  • FIG. 5 shows, with a view from the reflector lamp 2 on the circular Meßkopf cup 4 an example of the arrangement of several coupling optics radially symmetrical to the direction of irradiation of the light on the measuring surface.
  • the other coupling optics like the coupling optics 19, are each followed by an optical waveguide in which the measuring surface is reflected by the measuring head window 4 into the measuring head 1 and deflected by the coupling optics collected light is first forwarded to the shutter 20, from where it via the common optical waveguide 14 and the entrance slit 21 on the receiving surface 22 passes.
  • embodiments are included in the inventive concept in which the spectrometer has only one entrance slit, the light paths are brought together in front of the spectrometer and then the light passes through the one entrance slit and the respective spectrum is imaged on the receiving surface 22.
  • a particular advantage of the arrangement according to the invention is that it can be used both for measuring the direct reflection from a sample surface and for measuring the scattered reflection of a sample.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

L'invention concerne un dispositif pour mesurer le degré de réflexion de la réflexion directe ou dispersée sur un échantillon (8), avec une source lumineuse pour éclairer séparément l'échantillon (8) d'une part et des surfaces de référence d'autre part. En plus de la source lumineuse qui est de préférence une lampe à réflecteur (2), le dispositif comprend : un étalon blanc (6), un étalon noir (7) et la surface de l'échantillon (8) pour représenter une surface de mesure, sachant que l'étalon blanc (6), l'étalon noir (7) et l'échantillon (8) sont interchangés dans un ordre prédéfini; des moyens pour mesurer l'intensité de la lumière réfléchie par une surface blanche interne (10) et pour mesurer l'intensité de la lumière respectivement réfléchie par la surface de mesure; et un montage d'interprétation, qui est conçu pour enregistrer les valeurs d'intensité mesurées et pour les corréler par le calcul au degré de réflexion.
EP08862939A 2007-12-19 2008-12-10 Dispositif pour déterminer le degré de réflexion d'un échantillon Withdrawn EP2235503A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007061213A DE102007061213A1 (de) 2007-12-19 2007-12-19 Anordnung zum Bestimmen des Reflexionsgrades einer Probe
PCT/EP2008/010454 WO2009077110A1 (fr) 2007-12-19 2008-12-10 Dispositif pour déterminer le degré de réflexion d'un échantillon

Publications (1)

Publication Number Publication Date
EP2235503A1 true EP2235503A1 (fr) 2010-10-06

Family

ID=40404968

Family Applications (1)

Application Number Title Priority Date Filing Date
EP08862939A Withdrawn EP2235503A1 (fr) 2007-12-19 2008-12-10 Dispositif pour déterminer le degré de réflexion d'un échantillon

Country Status (4)

Country Link
US (1) US20110007319A1 (fr)
EP (1) EP2235503A1 (fr)
DE (1) DE102007061213A1 (fr)
WO (1) WO2009077110A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009030468A1 (de) 2009-06-23 2011-01-05 Carl Zeiss Microlmaging Gmbh Vorrichtung für die optische Spektroskopie und mechanischer Schalter für eine solche Vorrichtung
JP5302133B2 (ja) 2009-08-07 2013-10-02 株式会社堀場製作所 干渉膜厚計
DE102010041793A1 (de) 2010-09-30 2012-04-05 Carl Zeiss Microlmaging Gmbh Spektroskopische Messeinrichtung
EP3714685A1 (fr) 2019-03-25 2020-09-30 Trioliet B.V. Dispositif de traitement du produit de la récolte, de l'aliment pour animaux ou de leurs composants, système de détection nir électronique et procédé de calibrage
US11287317B2 (en) 2019-08-27 2022-03-29 Viavi Solutions Inc. Optical measurement device including internal spectral reference

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DE3701721A1 (de) * 1987-01-22 1988-08-04 Zeiss Carl Fa Remissionsmessgeraet zur beruehrungslosen messung
US4932779A (en) * 1989-01-05 1990-06-12 Byk Gardner, Inc. Color measuring instrument with integrating sphere
US5313542A (en) * 1992-11-30 1994-05-17 Breault Research Organization, Inc. Apparatus and method of rapidly measuring hemispherical scattered or radiated light
DE10010213B4 (de) * 2000-03-02 2005-02-17 Carl Zeiss Jena Gmbh Optische Meßvorrichtung, insbesondere zur Qualitätsüberwachung bei kontinuierlichen Prozessen
DE10143602B4 (de) * 2001-09-06 2007-08-23 Display-Messtechnik & Systeme Gmbh & Co.Kg Einrichtung zur meßtechnischen Bewertung von reflektierenden Objekten, insbesondere von reflektiven Anzeigen
DE102004048102A1 (de) * 2004-04-30 2006-04-20 Carl Zeiss Jena Gmbh Spektrometrischer Messkopf und Verfahren zu dessen Rekalibrierung
DE102004021448B4 (de) * 2004-04-30 2016-12-29 Carl Zeiss Spectroscopy Gmbh Spektrometrischer Reflexionsmesskopf und Verfahren zu dessen interner Rekalibrierung
DE102004048103B4 (de) * 2004-09-30 2017-01-12 Carl Zeiss Spectroscopy Gmbh Spektrometrischer Messkopf für Erntemaschinen und andere landwirtschaftlich genutzte Maschinen
DE102006035906A1 (de) * 2006-07-31 2008-04-17 Claas Selbstfahrende Erntemaschinen Gmbh Messvorrichtung zur Inhaltsstofferfassung

Non-Patent Citations (1)

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See references of WO2009077110A1 *

Also Published As

Publication number Publication date
DE102007061213A1 (de) 2009-06-25
WO2009077110A1 (fr) 2009-06-25
US20110007319A1 (en) 2011-01-13

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