EP1844294A1 - Dispositif permettant de determiner la position de zones espacees d'objets transparents et/ou diffus - Google Patents

Dispositif permettant de determiner la position de zones espacees d'objets transparents et/ou diffus

Info

Publication number
EP1844294A1
EP1844294A1 EP06706467A EP06706467A EP1844294A1 EP 1844294 A1 EP1844294 A1 EP 1844294A1 EP 06706467 A EP06706467 A EP 06706467A EP 06706467 A EP06706467 A EP 06706467A EP 1844294 A1 EP1844294 A1 EP 1844294A1
Authority
EP
European Patent Office
Prior art keywords
scanning
reference beam
scanning table
mirrors
mirror
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Withdrawn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
EP06706467A
Other languages
German (de)
English (en)
Inventor
Adolf Friedrich Fercher
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 Meditec AG
Original Assignee
Carl Zeiss Meditec AG
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 Meditec AG filed Critical Carl Zeiss Meditec AG
Publication of EP1844294A1 publication Critical patent/EP1844294A1/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Withdrawn legal-status Critical Current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
    • G01B9/02015—Interferometers characterised by the beam path configuration
    • G01B9/02027—Two or more interferometric channels or interferometers
    • G01B9/02028—Two or more reference or object arms in one interferometer
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
    • A61B3/1005—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for measuring distances inside the eye, e.g. thickness of the cornea
    • 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
    • G01B9/02058—Passive reduction of errors by particular optical compensation or alignment elements, e.g. dispersion compensation
    • 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
    • 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
    • G01B2290/35—Mechanical variable delay line

Definitions

  • the proposed invention relates to a method and an arrangement for determining the thickness, spacing and / or profile of mutually distanced regions of a transparent and / or diffuse object.
  • the solution for measuring partial distances i. H. suitable for distances between surfaces, interfaces or imperfections in the eye.
  • the measurement of these segments is of particular importance for cataract surgery and refractive eye surgery.
  • the determination of the length of the individual axial eye sections can be carried out by means of acoustic or optical length measuring methods. Short-coherence interferometry is becoming increasingly widespread due to the advantages of non-contact and high-precision operation.
  • short-coherence interferometry arrangements according to the Michelson principle are used, in which the beam of a short-coherent radiation source is split into a measuring beam and a reference beam. If the coherence length of the light used is smaller than the optical path length between the interfaces to be measured, no interference occurs between the light bundles reflected by the boundary surfaces.
  • the path length change carried out in the reference beam path with the aid of a reference mirror leads to interference after being combined by the measuring and reference beam, in the event that the path lengths of the measuring and reference beams are identical.
  • the path length change for example, by translational movement of the reference mirror (according to DE 32 01 801 C2) or by rotation of a transparent cube (according to WO 96/35100) take place.
  • the resulting interference patterns are passed to a detector and evaluated accordingly.
  • the path length change of the reference beam is a direct measure of the sought distance between the interfaces of the eye.
  • the reference mirror travels a distance corresponding to the distance to be measured while the measured object is at rest. Since it is difficult to fix an eye for the duration of the measurement of distances of about 30 mm, special solutions have been developed for ophthalmological applications, which also allow measurements on living objects. Measurement errors caused by inadequate fixation of the eye to be measured can be avoided by scanning distances of only a few millimeters.
  • WO 01/38820 A1 describes a solution which illuminates / scans two areas of an eye that are distanced in depth with a double beam.
  • a partial beam is faded out of the measuring beam focused on a first boundary surface in front of the measurement object, passed over a so-called detour unit and focused onto a second boundary surface of the eye.
  • a single measurement thus processes reflections at several interfaces of the eye almost simultaneously.
  • the rays have different optical properties, such as wavelength, polarization state o. ⁇ ..
  • the evaluation of the two measuring beams is effected by path length change of the reference beam, whereby different interference patterns are generated for the different measuring beams.
  • the described arrangements have the disadvantage that the measuring beams at the same time illuminate / scan two or more interfaces, as a result of which the radiation which does not contribute to the measurement generates a disturbing background and noise.
  • the present invention has for its object to develop a short-coherent interferometer arrangement, with the partial distances of an eye with high accuracy, can be measured easily and quickly.
  • the device according to the invention for determining the position of mutually distanced regions in transparent and / or diffuse objects provides for the use of an interferometer arrangement according to the Michelson principle.
  • a scanning unit is arranged, which consists of a scanning table, which is translationally movable in corresponding guides.
  • the direction of movement includes an angle ⁇ to the reference beam.
  • At least two reference mirrors are arranged on the scanning table, which have a decency d in the direction of the reference beam and overlap slightly laterally, so that during the motor-oscillating movement of the scanning table the reference beam is reflected in first only by the first and then by the second reference mirror.
  • the device according to the invention is suitable for determining the position of spaced-apart object regions in transparent and / or diffuse objects and, in particular, for measuring partial sections between surfaces, interfaces or imperfections in the eye.
  • the measurement of partial distances in the eye is of particular importance for cataract surgery and refractive eye surgery and is becoming increasingly widespread.
  • Figure 1 a scanning unit with two reference mirrors
  • Figure 2 a scanning unit with two, serving as a reference mirror prisms.
  • the device according to the invention for determining the position of mutually distanced regions in transparent and / or diffuse objects provides for the use of an interferometer arrangement according to the Michelson principle.
  • a scanning unit is arranged in the reference or measuring beam path.
  • the scanning unit consists of a scanning table, which is translationally movable in corresponding guides, wherein the direction of movement forms an angle ⁇ to the reference beam.
  • At least two reference mirrors are arranged on the scanning table, which have a decency d in the direction of the reference beam and overlap slightly laterally, so that during the motor-oscillating movement of the scanning table the reference beam is reflected in first only by the first and then by the second reference mirror.
  • FIG. 1 shows a first embodiment variant of a scanning unit 2 to be arranged in the reference beam path 1 with two reference mirrors 3 and 4.
  • the scanning table 5 of the scanning unit 2 is moved by a motor 6 in corresponding guides 7 translationally, oscillating, wherein the direction of movement 8 forms an angle ⁇ to the reference beam 1.
  • step or piezomotors are used. But it is also possible to use voice coil or ultrasonic piezo scanners.
  • the components angle ⁇ , distance d and extension a are coordinated so that the technical problem can be solved with the arrangement.
  • the two reference mirrors 3 and 4 are arranged, which have a distance d and a lateral extent a in the direction of the reference beam 1, which is preferably the same for both reference mirrors 3 and 4.
  • the reference beam 1 is successively reflected by the reference mirrors 3 and 4 in itself.
  • the representation of the reference beam 1 as a deflected beam is only a better illustration.
  • the oscillating movement of the scanning table 5 should be clarified by the scanning table 5 'with the reference mirrors 3' and 4 '.
  • the reference beam 1 is either reflected by the reference mirror 3 or 4 'in itself.
  • the distance d of the reference mirrors 3 and 4 can be varied.
  • the scanning time can be considerably shortened become.
  • the two reference beams thus always have a difference in length of 2d.
  • the scanning unit 2 In order to use the device for different distances to the object to be measured, it is also advantageous to make the scanning unit 2 as a whole displaceable.
  • the accuracy of the interferometer arrangement is impaired by dispersion in the individual measuring arms. To achieve maximum accuracy, the dispersion in both interferometer arms must be as equal as possible. While the component-related dispersion can be corrected by correspondingly thick flat plates, two wedge plates in the reference beam path are required for the compensation of object-related dispersion, which are shifted accordingly against each other.
  • 3 and 4 plane plates 9 and / or wedge plates 10 can be arranged in front of the reference mirrors.
  • the refractions occurring during the alignment of the reference mirrors 3 and 4 must be taken into account.
  • more than two reference mirrors with different distances d can be arranged on the scanning table 5. As a result, it can be ensured that the position of more than two mutually distanced regions can be determined with one scanning operation.
  • FIG. 2 shows a further advantageous embodiment, in which two prisms 11 and 12 are arranged as reference mirror on the scanning table 5 of the scanning unit 2.
  • the prisms 11 and 12 used can be dimensioned so that wedge plates 10 can be dispensed with.
  • the prism 12 has a longer glass path.
  • the scanning table 5 is moved by a motor 6 in corresponding guides 7 in a translatory, oscillating manner, wherein the direction of movement 8 encloses an angle ⁇ to the reference beam 1.
  • two prisms 11 and 12 are arranged, which have a decency d and a lateral extent a in the direction of the reference beam 1, which is preferably the same for both prisms 11 and 12. ,
  • 11 and 12 flat plates 9 and / or wedge plates 10 can be arranged for dispersion compensation in front of the prisms. The refractions occurring during the alignment of the reference mirrors 3 and 4 must be taken into account.
  • the representation of the reference beam 1 as a deflected beam is only a better illustration.
  • the oscillating movement of the scanning table 5 is to be clarified by the scan table 5 'with the prisms 11' and 12 'shown in a thin manner.
  • the reference beam 1 is either reflected by the prism 11 or 12 'in itself.
  • the additionally existing mirror 13 can also be designed as a prism.
  • the influence of tilting, which is caused by an inaccurate arrangement or incorrect guides 7 and deteriorate the interferometer signal is reduced.
  • the reference beams thus generated are superimposed with the measurement beams reflected at the object areas (interfaces) to be determined, imaged on a detector and evaluated.
  • the Weglärrgen provided in the reference beam with the help of the reference mirrors 3 and 4 and the prisms 11 and 12 leads to interference, in the event that the path lengths of measuring and reference beam are identical.
  • the path length change of the reference beam is a direct measure of the distance to be determined between the distanced areas of the object.
  • a reference mirror with a prism
  • a simple dispersion compensation is possible because the prism has the corresponding glass path.
  • the measurement beams are focused one after the other onto the corresponding areas, since the scattered light portions are thereby significantly lower and the signal quality is increased.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Biophysics (AREA)
  • Ophthalmology & Optometry (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne un dispositif permettant de déterminer une épaisseur, une distance et/ou un profil de zones espacées d'un objet transparent et/ou diffus, notamment destiné à la mesure de distances dans l'oeil. En ce qui concerne le dispositif de détermination d'une position à l'aide d'un système interféromètre d'après le principe de Michelson, on implante une unité scanner (2) dans la trajectoire du faisceau de référence ou la trajectoire du faisceau de mesure pour modifier la longueur d'onde, cette unité scanner étant constituée d'une table de scannage (5) qui est mobile en translation dans des éléments de guidage adéquats. La direction de déplacement forme avec le faisceau de référence (1) un angle a. Sur la table de scannage (5) sont placés au moins deux miroirs de référence (3, 4) qui présentent dans la direction du faisceau de référence (1) une distance d et se chevauchent latéralement légèrement de telle façon que pendant le déplacement de va-et-vient de la table de scannage (5) par la commande d'un moteur, le faisceau de référence (1) est réfléchi d'abord par le premier miroir de référence (3) puis par le deuxième miroir de référence (4).
EP06706467A 2005-02-04 2006-01-28 Dispositif permettant de determiner la position de zones espacees d'objets transparents et/ou diffus Withdrawn EP1844294A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102005005816A DE102005005816A1 (de) 2005-02-04 2005-02-04 Vorrichtung zur Positionsbestimmung voneinander distanzierter Bereiche in transparenten und/oder diffusen Objekten
PCT/EP2006/000751 WO2006081998A1 (fr) 2005-02-04 2006-01-28 Dispositif permettant de determiner la position de zones espacees d'objets transparents et/ou diffus

Publications (1)

Publication Number Publication Date
EP1844294A1 true EP1844294A1 (fr) 2007-10-17

Family

ID=36177784

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06706467A Withdrawn EP1844294A1 (fr) 2005-02-04 2006-01-28 Dispositif permettant de determiner la position de zones espacees d'objets transparents et/ou diffus

Country Status (5)

Country Link
US (1) US7656537B2 (fr)
EP (1) EP1844294A1 (fr)
JP (1) JP4871297B2 (fr)
DE (1) DE102005005816A1 (fr)
WO (1) WO2006081998A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7800759B2 (en) 2007-12-11 2010-09-21 Bausch & Lomb Incorporated Eye length measurement apparatus
EP2230990B1 (fr) * 2007-12-21 2016-12-14 Bausch & Lomb Incorporated Appareil d'alignement d'un instrument ophtalmique et procédé pour son utilisation
US8294971B2 (en) 2008-12-18 2012-10-23 Bausch • Lomb Incorporated Apparatus comprising an optical path delay scanner
US8792105B2 (en) * 2010-01-19 2014-07-29 Si-Ware Systems Interferometer with variable optical path length reference mirror using overlapping depth scan signals
JP5397817B2 (ja) * 2010-02-05 2014-01-22 国立大学法人名古屋大学 干渉測定装置および測定方法
US20160054195A1 (en) * 2014-08-20 2016-02-25 Johnson & Johnson Vision Care, Inc. System and methods for measuring ophthalmic lens
CN104545786B (zh) * 2015-01-14 2016-02-24 哈尔滨医科大学 条纹视力测试仪

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DE3201801A1 (de) * 1982-01-21 1983-09-08 Adolf Friedrich Prof. Dr.-Phys. 4300 Essen Fercher Verfahren und anordnung zur messung der teilstrecken des lebenden auges
EP0877913B1 (fr) * 1995-05-04 2002-10-09 Haag-Streit AG Dispositif pour la mesure d'epaisseur d'objets transparents
US5825493A (en) * 1996-06-28 1998-10-20 Raytheon Company Compact high resolution interferometer with short stroke reactionless drive
JP2805045B2 (ja) * 1996-08-27 1998-09-30 工業技術院長 空間位置決め方法
JPH11142243A (ja) * 1997-11-13 1999-05-28 Yokogawa Electric Corp 干渉計及びこれを用いたフーリエ変換型分光装置
US6175669B1 (en) * 1998-03-30 2001-01-16 The Regents Of The Universtiy Of California Optical coherence domain reflectometry guidewire
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US6806963B1 (en) * 1999-11-24 2004-10-19 Haag-Streit Ag Method and device for measuring the optical properties of at least two regions located at a distance from one another in a transparent and/or diffuse object
JP2004502954A (ja) * 2000-07-07 2004-01-29 ローベルト　ボツシユ　ゲゼルシヤフト　ミツト　ベシユレンクテル　ハフツング 干渉測定装置
AU2003218590A1 (en) * 2002-04-18 2003-10-27 Haag-Streit Ag Measurement of optical properties
US20050140981A1 (en) * 2002-04-18 2005-06-30 Rudolf Waelti Measurement of optical properties
JP3667716B2 (ja) * 2002-05-13 2005-07-06 直弘 丹野 光コヒーレンストモグラフィー装置
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See references of WO2006081998A1 *

Also Published As

Publication number Publication date
US20070291276A1 (en) 2007-12-20
JP4871297B2 (ja) 2012-02-08
JP2008528218A (ja) 2008-07-31
WO2006081998A1 (fr) 2006-08-10
US7656537B2 (en) 2010-02-02
DE102005005816A1 (de) 2006-08-17

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