EP2132522A2 - Optical metrology system - Google Patents
Optical metrology systemInfo
- Publication number
- EP2132522A2 EP2132522A2 EP08762037A EP08762037A EP2132522A2 EP 2132522 A2 EP2132522 A2 EP 2132522A2 EP 08762037 A EP08762037 A EP 08762037A EP 08762037 A EP08762037 A EP 08762037A EP 2132522 A2 EP2132522 A2 EP 2132522A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- slot
- signal
- beams
- positioning
- laser
- 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- Withdrawn
Links
- 230000003287 optical effect Effects 0.000 title claims description 25
- 238000001514 detection method Methods 0.000 claims abstract description 13
- 230000001360 synchronised effect Effects 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims description 7
- 230000035945 sensitivity Effects 0.000 claims description 7
- 230000000737 periodic effect Effects 0.000 claims description 6
- 238000000926 separation method Methods 0.000 claims description 2
- 239000013307 optical fiber Substances 0.000 description 13
- 238000006073 displacement reaction Methods 0.000 description 7
- 238000009826 distribution Methods 0.000 description 7
- 239000013078 crystal Substances 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000386 microscopy Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/342—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells the sensed object being the obturating part
Definitions
- the present invention relates to metrology systems and more particularly to optical metrology systems.
- Fiber optic displacement sensors use a set of optical fibers to emit a light beam that is reflected on an object or on a part of the object to be located. Other optical fibers guide the reflected or scattered light to a photocell that emits a measurement signal. The positioning of the object is determined by its nature and the amount of light received by the photocell relative to the amount of light emitted.
- Capacitive sensors are based on a capacitive coupling between the object to be positioned and a reference armature. The intensity of the coupling makes it possible to determine the distance between the armature and the object.
- Interferometric sensors have a very good sensitivity but are only suitable for identifying relative displacements.
- the object of the invention is to provide a metrology system which makes it possible to obtain a sub-nanometric precision achieved only by the interferometric systems, in a compact arrangement and therefore a system combining precision, compactness and low cost.
- the invention therefore relates to an optical positioning device comprising a laser, associated with an acousto-optical modulator for emitting at least two parallel laser beams modulated in phase opposition, said beams being focused on a slot integral with the object to position and perpendicular to the positioning direction, and a photodiode adapted to collect the beams from the slot and associated with a synchronous detection amplifier for providing a signal reflecting the position of the slot relative to the reference position.
- the positioning device may further comprise an optical system capable of collimating, focusing and collecting the laser beams.
- the positioning device may also comprise an electrical function generator and an oscillator, the oscillator emitting at its output a radio frequency signal having a frequency modulation by a periodic electrical signal, in particular by a rectangular-shaped signal of lower frequency emitted by the electrical function generator, the radio frequency periodic signal being sent to the acousto-optic modulator to control the separation of the laser beams.
- the electrical signal delivered by the electrical function generator may be a reference signal for the synchronous detection amplifier.
- Another object of the invention is a method of positioning an object with respect to a reference position in which the variation of position of the object relative to the reference is detected as a function of the variation.
- IEC 60050 International Electrotechnical Vocabulary - Details for IEV number 845-28-55 Printed on 6-12-10 12:03:20
- EDT Optical fiber intensity of two modulated laser beams in phase opposition emerging from a slot integral with the object to
- the sensitivity of the device can be adjusted by changing the width of the hardware slot. It is still possible to detect the variation of intensity of the laser beams emerging from the slot by means of a photodiode.
- a synchronously detecting position signal can be obtained from the signal from the photodiode collecting the emerging laser beams.
- An error signal can be obtained in parallel with a position signal after the synchronous detection.
- FIG. 1 depicts an embodiment of the optical positioning device according to the invention
- FIG. 1b describes another embodiment of the optical positioning device according to the invention.
- FIG. 2 schematically describes the positioning of the laser beams and of the slot
- the metrology device essentially comprises a laser 1 whose beam enters an acousto-optical modulator 3 and also comprises a periodic function generator 7 connected to a synchronous detection amplifier 9. a connection 8 and a radio frequency oscillator 5 which communicates with the periodic function generator 7 via the connection 6 and with the acousto-optical modulator 3 via the connection 4.
- the acousto-optical modulator 3 is connected by at least two of its outputs to two single-mode fibers 10, themselves connected to collimators 11.
- the collimators 11 are positioned in an optical system comprising a lens L 1 followed by a lens L 2 and a multimode fiber 12.
- the output of the multimode fiber 12 is connected to a photodiode 13 itself connected to the synchronous detection amplifier 9 via the connection 14.
- FIG. 1a shows the general structure of a positioning device according to the invention. It is intended to position an object OBJ with respect to the optical part OPT of the optical positioning device.
- the laser 1 is configured to emit a Gaussian type wave having an electromagnetic transverse mode of (0; 0) type.
- Figure 3 shows the intensity profile 19 of such a wave in the direction x.
- the acousto-optic modulator 3 is based on the principle of Bragg diffraction.
- a sound wave is generated in a crystal by a radiofrequency wave which generates a deformation of the crystal showing a network type structure.
- a diffraction intervenes separating the laser beam into two beams.
- the distribution of the total intensity between the two beams depends on the angle between the incident beam and the sound wave in the crystal, in agreement with the Bragg equations.
- the sound wave of the acoustooptic modulator 3 is modulated by a low frequency signal from the low frequency generator 7.
- the distribution of the intensity between the two beams will be modulated by the energy modulation of the sound wave, thus according to the power of the radiofrequency wave injected into the acousto - optic modulator.
- the two emerging beams of the acousto-optic modulator 3 are then in phase opposition.
- Figure Ib shows another embodiment of the invention.
- the acousto-optic modulator 3 has been removed in favor of two lasers Ia and Ib.
- the laser is connected by the link 4a to the low frequency generator 7.
- the laser I b is connected by the link 4b to the low frequency generator 7. At the output, they are connected to the monomode optical fibers 10.
- Both lasers 1a and 1b are controlled by the low frequency generator 7 so as to emit alternately. We obtain two beams modulated in opposition of phase. The rest of the device is identical to the device described in FIG.
- Each of these two beams is guided by a monomode optical fiber 10 followed by a collimator 1 1.
- the collimators 1 1 make it possible to align the beams with each other, with respect to the optical axis formed by the lenses L1 and L2 and with respect to at the slot F.
- the beams are then focused by the lens L1 upstream of the slot F.
- the emerging beams converge through the lens L2 to the input of the multimode optical fiber 12 which opens on the photodiode 13.
- the photodiode 13 emits an electrical signal to the synchronous detection amplifier 9.
- the synchronous detection amplifier 9 receives on its reference input the low frequency signal coming from the low frequency generator 7 which was used to modulate the incident wave on the acousto-optical modulator 3.
- the synchronous detection amplifier 9 isolates the signals having the same frequency as the low frequency signal among all the signals coming from the photodiode 13. The isolated signals are then emitted by the link 15.
- a Gaussian wave has the intensity distribution 19 of FIG. 3, ie a Gaussian type distribution passing through a maximum and tending towards a minimum along the two directions of the abscissa axis. Because of the shape of the intensity curve as a function of position, a given intensity can correspond to two positions. One can not determine the absolute position of the obj and.
- the intensity distribution 21 of FIG. 3 is obtained at the output of slot F.
- the slot F moves in the plane formed by the two beams along the axis 18, the slot F being perpendicular to said plane.
- the little side of the slot is in the direction of displacement 18 and the long side is perpendicular to the direction of movement 18.
- the extreme positions are the positions where the overlap between the beams is zero.
- a forbidden position exists at the point of convergence of the beams, where the intensity profile at the exit of the slot F does not make it possible to determine the position of the slot F.
- the slot F is equivalent in size to the width of the focusing spot of a laser beam, the dimensions of which are equal to or greater than the square of the wavelength of the laser beam.
- the slot F moves, it occultly conceals a laser beam and the other.
- the two laser beams being in phase opposition and spatially shifted at the slot, the contribution of each laser beam to the total intensity at the exit of the slot can be determined. It can be shown that the intensity profile at the exit of the slot as a function of the position describes a Gaussian shape curve canceling at the origin of the abscissae and presenting a minimum and a maximum on both sides of the 'origin.
- the optical wave positioning device makes it possible to position, relative to the optical part OPT of the device and with precision, an object integral with a slot F whose small width corresponds to the positioning direction.
- the mass of the slot F can be considered negligible compared to the mass of the OBJ object.
- the optical positioning device can be broken down into a frame 16 and an optical part OPT connected by optical fibers.
- the optical positioning device thus has the particularity of being able to operate with the OPT optical part operating in various media including vacuum and liquids.
- the optical portion OPT being connected by optical fibers, its location is limited only by the absorption of said optical fibers due to the length of said optical fibers. It is thus possible to design applications in hostile environments, for example for the measurement of elements or cracks in the nucleus of a nuclear power plant.
- the OPT optical part has no electrical or electronic system, it has no sensitivity to electromagnetic waves, allowing it to operate in harsh environments, such as power plants, radar radomes or explosive atmospheres.
- the optical positioning device could also find an application in ultrasensitive seismology, thanks to its high sensitivity, or in the application of metrology in microscopy, such as near-field microscopy. It may be envisaged to integrate the various elements of the device by microelectronic techniques using, for example, VECSEL type lasers and waveguides to replace the optical fibers. Likewise, a large part of the totality of the control electronics can be integrated, making it possible to obtain a compact positioning device with a high degree of accuracy.
- a device comprising a higher number of laser beams.
- four laser beams could control the movement of an object in two distinct directions.
- the slot would be replaced by a hole, each pair of beams to determine the displacement of the hole in a direction within the diameter of said hole.
- optical fibers could be removed.
- the laser beams would be directly collimated at the output of the acousto-optic modulator and the photodiode disposed directly at the output of the optical system. This approach could also be combined with the use of two lasers instead of the acousto-optic modulator as described in the alternative embodiment to reduce costs even more drastically.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention relates to a device for positioning an object relative to a reference position, characterised in that it comprises a laser (1) associated with an acoustic-optical modulator (3) for transmitting at least two parallel and modulated phase-opposed laser beams, said beams being focused on a slot (F) connected to the object to be positioned (OBJ), the larger side of the slot (F) being perpendicular to the positioning direction, and a photodiode (13) adapted for collecting the beams from the slot (F) and associated with a synchronous detection amplifier (9) for supplying a signal indicative of the slot (F) position relative to the reference position.
Description
Système de métrologie optique Optical metrology system
La présente invention concerne les systèmes de métrologie et plus particulièrement les systèmes de métrologie optique.The present invention relates to metrology systems and more particularly to optical metrology systems.
Le positionnement d'objets massifs avec une grande précision nécessite généralement un système de positionnement encombrant ou sensible à l' environnement. Certaines applications ne peuvent permettre de telles contraintes, notamment dans le domaine spatial où les contraintes de poids et de volume se répercutent directement sur les coûts, par exemple les coûts de mise en orbite d'un satellite.The positioning of massive objects with great precision generally requires a cumbersome or environmentally sensitive positioning system. Some applications can not allow such constraints, especially in the space domain where the constraints of weight and volume have a direct impact on costs, for example the costs of putting a satellite in orbit.
Parmi les dispositifs de positionnement optique existants, on peut citer les dispositifs de déplacement à fibres optiques, les capteurs capacitifs ou encore les capteurs interférométriques. Les capteurs de déplacement à fibre optique utilisent un ensemble de fibres optiques pour émettre un faisceau lumineux qui vient se réfléchir sur un objet ou sur une partie de l'objet à localiser. D'autres fibres optiques permettent de guider la lumière réfléchie ou diffusée vers une cellule photoélectrique qui émet un signal de mesure. Le positionnement de l 'objet est déterminé d' après sa nature et la quantité de lumière reçue par la cellule photoélectrique par rapport à la quantité de lumière émise.Among the existing optical positioning devices, mention may be made of optical fiber displacement devices, capacitive sensors or interferometric sensors. Fiber optic displacement sensors use a set of optical fibers to emit a light beam that is reflected on an object or on a part of the object to be located. Other optical fibers guide the reflected or scattered light to a photocell that emits a measurement signal. The positioning of the object is determined by its nature and the amount of light received by the photocell relative to the amount of light emitted.
Les capteurs capacitifs sont basés sur un couplage capacitif entre l'objet à positionner et une armature de référence. L' intensité du couplage permet de déterminer la distance entre l ' armature et l'objet.Capacitive sensors are based on a capacitive coupling between the object to be positioned and a reference armature. The intensity of the coupling makes it possible to determine the distance between the armature and the object.
Les règles optiques sont peu adaptées aux applications de précision nécessitant compacité, sensibilité et légèreté de l'élément sensible au déplacement.Optical rules are poorly suited to precision applications requiring the compactness, sensitivity and lightness of the displacement sensitive element.
Les capteurs interférométriques ont une très bonne sensibilité mais ne sont adaptés qu'à l 'identification des déplacements relatifs.Interferometric sensors have a very good sensitivity but are only suitable for identifying relative displacements.
Au vu de ce qui précède, le but de l'invention est de fournir un système de métrologie qui permette d'obtenir une précision sub- nanométrique atteinte uniquement par les systèmes interférométriques,
dans un agencement compact et donc un système combinant précision, compacité et faible coût.In view of the foregoing, the object of the invention is to provide a metrology system which makes it possible to obtain a sub-nanometric precision achieved only by the interferometric systems, in a compact arrangement and therefore a system combining precision, compactness and low cost.
L' invention a donc pour objet un dispositif de positionnement optique comprenant un laser, associé à un modulateur acousto-optique pour émettre au moins deux faisceaux lasers parallèles modulés en opposition de phase, lesdits faisceaux étant focalisés sur une fente solidaire de l'objet à positionner et perpendiculaire à la direction de positionnement, et une photodiode adaptée pour collecter les faisceaux issus de la fente et associée à un amplificateur à détection synchrone pour délivrer un signal traduisant la position de la fente par rapport à la position de référence.The invention therefore relates to an optical positioning device comprising a laser, associated with an acousto-optical modulator for emitting at least two parallel laser beams modulated in phase opposition, said beams being focused on a slot integral with the object to position and perpendicular to the positioning direction, and a photodiode adapted to collect the beams from the slot and associated with a synchronous detection amplifier for providing a signal reflecting the position of the slot relative to the reference position.
Le dispositif de positionnement peut en outre comprendre un système optique apte à collimater, focaliser et collecter les faisceaux laser. Le dispositif de positionnement peut également comprendre un générateur de fonction électrique et un oscillateur, l'oscillateur émettant à sa sortie un signal radiofréquence présentant une modulation de fréquence par un signal électrique périodique, notamment par un signal de forme rectangulaire, de plus basse fréquence émis par le générateur de fonction électrique, le signal périodique radiofréquence étant envoyé vers le modulateur acousto- optique afin de commander la séparation des faisceaux laser.The positioning device may further comprise an optical system capable of collimating, focusing and collecting the laser beams. The positioning device may also comprise an electrical function generator and an oscillator, the oscillator emitting at its output a radio frequency signal having a frequency modulation by a periodic electrical signal, in particular by a rectangular-shaped signal of lower frequency emitted by the electrical function generator, the radio frequency periodic signal being sent to the acousto-optic modulator to control the separation of the laser beams.
Dans un dispositif de positionnement tel que défini ci-dessus, le signal électrique délivré par le générateur de fonction électrique peut être un signal de référence pour l'amplificateur à détection synchrone.In a positioning device as defined above, the electrical signal delivered by the electrical function generator may be a reference signal for the synchronous detection amplifier.
L' invention a également pour objet, selon un autre aspect, un procédé de positionnement d'un objet par rapport à une position de référence dans lequel on détecte la variation de position de l 'objet par rapport à la référence en fonction de la variation d' intensité de deux faisceaux laser modulés en opposition de phase émergeants d'une fente solidaire de l 'objet à positionner.Another object of the invention is a method of positioning an object with respect to a reference position in which the variation of position of the object relative to the reference is detected as a function of the variation. IEC 60050 - International Electrotechnical Vocabulary - Details for IEV number 845-28-55 Printed on 6-12-10 12:03:20 EDT - Optical fiber intensity of two modulated laser beams in phase opposition emerging from a slot integral with the object to
On peut ajuster la sensibilité du dispositif en modifiant la largeur de la fente matérielle.
On peut encore détecter la variation d'intensité des faisceaux laser émergents de la fente grâce à une photodiode.The sensitivity of the device can be adjusted by changing the width of the hardware slot. It is still possible to detect the variation of intensity of the laser beams emerging from the slot by means of a photodiode.
On peut obtenir un signal de position par détection synchrone à partir du signal provenant de la photodiode collectant les faisceaux lasers émergents.A synchronously detecting position signal can be obtained from the signal from the photodiode collecting the emerging laser beams.
On peut obtenir un signal d'erreur en parallèle d'un signal de position après la détection synchrone.An error signal can be obtained in parallel with a position signal after the synchronous detection.
D'autres buts, caractéristiques et avantages de l' invention apparaîtront à la lecture de la description suivante, donnée uniquement à titre d'exemple non limitatif et faite en référence aux dessins annexés sur lesquels :Other objects, features and advantages of the invention will appear on reading the following description, given solely by way of nonlimiting example and with reference to the appended drawings in which:
-la figure l a décrit un mode de réalisation du dispositif de positionnement optique selon l' invention ;FIG. 1 depicts an embodiment of the optical positioning device according to the invention;
-la figure I b décrit un autre mode de réalisation du dispositif de positionnement optique selon l 'invention ;FIG. 1b describes another embodiment of the optical positioning device according to the invention;
-la figure 2 décrit schématiquement le positionnement des faisceaux laser et de la fente ;FIG. 2 schematically describes the positioning of the laser beams and of the slot;
- la figure 3 décrit des répartitions spatiales d' intensité obtenues au moyen du dispositif de positionnement optique, avant et après la fente.- Figure 3 describes spatial distributions of intensity obtained by means of the optical positioning device, before and after the slot.
En se référant tout d'abord à la figure l a, le dispositif de métrologie comprend essentiellement un laser 1 dont le faisceau pénètre dans un modulateur acousto-optique 3 et comprend également un générateur de fonction périodique 7 connecté à un amplificateur à détection synchrone 9 par une connexion 8 et un oscillateur radiofréquence 5 qui communique avec le générateur de fonction périodique 7 par la connexion 6 et avec le modulateur acousto-optique 3 par la connexion 4.Referring firstly to FIG. 1a, the metrology device essentially comprises a laser 1 whose beam enters an acousto-optical modulator 3 and also comprises a periodic function generator 7 connected to a synchronous detection amplifier 9. a connection 8 and a radio frequency oscillator 5 which communicates with the periodic function generator 7 via the connection 6 and with the acousto-optical modulator 3 via the connection 4.
Le modulateur acousto-optique 3 est relié par au moins deux de ses sorties à deux fibres monomodes 10, elles-mêmes reliées à des collimateurs 1 1 . Les collimateurs 1 1 sont positionnés dans un système optique comprenant une lentille L l suivie d'une lentille L2 et d'une fibre multimode 12. La sortie de la fibre multimode 12 est reliée à une
photodiode 13 elle-même reliée à l'amplificateur à détection synchrone 9 par la connexion 14.The acousto-optical modulator 3 is connected by at least two of its outputs to two single-mode fibers 10, themselves connected to collimators 11. The collimators 11 are positioned in an optical system comprising a lens L 1 followed by a lens L 2 and a multimode fiber 12. The output of the multimode fiber 12 is connected to a photodiode 13 itself connected to the synchronous detection amplifier 9 via the connection 14.
Une fente F, solidaire de l'objet OBJ à positionner, est placée entre les lentilles Ll et L2. Sur la figure l a, on a représenté la structure générale d'un dispositif de positionnement selon l 'invention. Il est destiné à positionner un objet OBJ par rapport à la partie optique OPT du dispositif de positionnement optique.A slot F, integral with the object OBJ to be positioned, is placed between the lenses L1 and L2. FIG. 1a shows the general structure of a positioning device according to the invention. It is intended to position an object OBJ with respect to the optical part OPT of the optical positioning device.
Le laser 1 est configuré pour émettre une onde de type gaussien présentant un mode transverse électromagnétique de type (0;0). La figure 3 montre le profil d'intensité 19 d'une telle onde selon la direction x.The laser 1 is configured to emit a Gaussian type wave having an electromagnetic transverse mode of (0; 0) type. Figure 3 shows the intensity profile 19 of such a wave in the direction x.
Le modulateur acousto-optique 3 est basé sur le principe de la diffraction de Bragg. Une onde sonore est générée dans un cristal par une onde radiofréquence ce qui génère une déformation du cristal faisant apparaître une structure de type réseau. Lors de la traversée du cristal par un faisceau laser, une diffraction intervient séparant le faisceau laser en deux faisceaux. La répartition de l' intensité totale entre les deux faisceaux dépend alors de l'angle entre le faisceau incident et l 'onde sonore dans le cristal, en accord avec les équations de Bragg.The acousto-optic modulator 3 is based on the principle of Bragg diffraction. A sound wave is generated in a crystal by a radiofrequency wave which generates a deformation of the crystal showing a network type structure. During the crossing of the crystal by a laser beam, a diffraction intervenes separating the laser beam into two beams. The distribution of the total intensity between the two beams depends on the angle between the incident beam and the sound wave in the crystal, in agreement with the Bragg equations.
De plus, l' onde sonore du modulateur acousto-optique 3 est modulée par un signal basse fréquence issu du générateur basse fréquence 7. Pour un faisceau initial présentant un angle d' incidence donné, la répartition de l'intensité entre les deux faisceaux sera modulée par la modulation en énergie de l 'onde sonore, donc selon la puissance de l'onde radiofréquence injectée dans le modulateur acousto-optique. Les deux faisceaux émergents du modulateur acousto- optique 3 sont alors en opposition de phase. La figure I b montre un autre mode de réalisation de l' invention. Le modulateur acousto-optique 3 a été supprimé au profit de deux lasers l a et I b. Le laser l a est relié par la liaison 4a au générateur basse fréquence 7. De même, le laser I b est relié par la
liaison 4b au générateur basse fréquence 7. En sortie, ils sont reliés aux fibres optiques monomode 10.In addition, the sound wave of the acoustooptic modulator 3 is modulated by a low frequency signal from the low frequency generator 7. For an initial beam having a given angle of incidence, the distribution of the intensity between the two beams will be modulated by the energy modulation of the sound wave, thus according to the power of the radiofrequency wave injected into the acousto - optic modulator. The two emerging beams of the acousto-optic modulator 3 are then in phase opposition. Figure Ib shows another embodiment of the invention. The acousto-optic modulator 3 has been removed in favor of two lasers Ia and Ib. The laser is connected by the link 4a to the low frequency generator 7. Similarly, the laser I b is connected by the link 4b to the low frequency generator 7. At the output, they are connected to the monomode optical fibers 10.
Les deux lasers l a et I b sont commandés par le générateur basse fréquence 7 de façon à émettre en alternance. On obtient deux faisceaux modulés en opposition de phase. Le reste du dispositif est identique au dispositif décrit sur la figure l a.Both lasers 1a and 1b are controlled by the low frequency generator 7 so as to emit alternately. We obtain two beams modulated in opposition of phase. The rest of the device is identical to the device described in FIG.
Chacun de ces deux faisceaux est guidé par une fibre optique monomode 10 suivie par un collimateur 1 1. Les collimateurs 1 1 permettent d'aligner les faisceaux entre eux, par rapport à l 'axe optique formé par les lentilles Ll et L2 et par rapport à la fente F. Les faisceaux sont alors focalisés par la lentille Ll en amont de la fente F.Each of these two beams is guided by a monomode optical fiber 10 followed by a collimator 1 1. The collimators 1 1 make it possible to align the beams with each other, with respect to the optical axis formed by the lenses L1 and L2 and with respect to at the slot F. The beams are then focused by the lens L1 upstream of the slot F.
Les faisceaux émergents convergent à travers la lentille L2 vers l'entrée de la fibre optique multimode 12 qui débouche sur la photodiode 13. La photodiode 13 émet un signal électrique vers l'amplificateur 9 à détection synchrone.The emerging beams converge through the lens L2 to the input of the multimode optical fiber 12 which opens on the photodiode 13. The photodiode 13 emits an electrical signal to the synchronous detection amplifier 9.
L'amplificateur 9 à détection synchrone reçoit sur son entrée de référence le signal basse fréquence provenant du générateur basse fréquence 7 qui a servi à moduler l'onde incidente sur le modulateur acousto-optique 3. L'amplificateur 9 à détection synchrone isole les signaux présentant la même fréquence que le signal basse fréquence parmi tous les signaux provenant de la photodiode 13. Les signaux isolés sont alors émis par la liaison 15.The synchronous detection amplifier 9 receives on its reference input the low frequency signal coming from the low frequency generator 7 which was used to modulate the incident wave on the acousto-optical modulator 3. The synchronous detection amplifier 9 isolates the signals having the same frequency as the low frequency signal among all the signals coming from the photodiode 13. The isolated signals are then emitted by the link 15.
Une onde gaussienne présente la répartition d' intensité 19 de la figure 3 , soit une répartition de type gaussienne passant par un maximum et tendant vers un minimum selon les deux directions de l'axe des abscisses. A cause de la forme de la courbe d'intensité en fonction de la position, une intensité donnée peut correspondre à deux positions. On ne peut déterminer la position absolue de l'obj et.A Gaussian wave has the intensity distribution 19 of FIG. 3, ie a Gaussian type distribution passing through a maximum and tending towards a minimum along the two directions of the abscissa axis. Because of the shape of the intensity curve as a function of position, a given intensity can correspond to two positions. One can not determine the absolute position of the obj and.
En utilisant deux faisceaux gaussiens en opposition de phase, on obtient en sortie de la fente F la répartition d'intensité 21 de la figure 3.By using two Gaussian beams in phase opposition, the intensity distribution 21 of FIG. 3 is obtained at the output of slot F.
La fente F se déplace dans le plan formé par les deux faisceaux selon l 'axe 18, la fente F étant perpendiculaire au dit plan. Le petit
coté de la fente est dans la direction du déplacement 18 et le grand coté est perpendiculaire à la direction de déplacement 18.The slot F moves in the plane formed by the two beams along the axis 18, the slot F being perpendicular to said plane. The little side of the slot is in the direction of displacement 18 and the long side is perpendicular to the direction of movement 18.
Plusieurs positions sont possibles pour la fente F. Les positions extrêmes sont les positions où le recouvrement entre les faisceaux est nul. Une position interdite existe au point de convergence des faisceaux, où le profil d'intensité en sortie de la fente F ne permet pas de déterminer la position de la fente F.Several positions are possible for the slot F. The extreme positions are the positions where the overlap between the beams is zero. A forbidden position exists at the point of convergence of the beams, where the intensity profile at the exit of the slot F does not make it possible to determine the position of the slot F.
La fente F est de dimension équivalente à la largeur de la tache de focalisation d'un faisceau laser, dont les dimensions sont égales ou supérieures au carré de la longueur d'onde du faisceau laser. Lorsque la fente F se déplace, elle occulte successivement un faisceau laser puis l'autre. Les deux faisceaux laser étant en opposition de phase et décalés spatialement au niveau de la fente, on peut déterminer la contribution de chaque faisceau laser à l' intensité totale à la sortie de la fente. On peut montrer que le profil d'intensité à la sortie de la fente en fonction de la position décrit une courbe de forme gaussienne s'annulant à l 'origine des abscisses et présentant un minimum et un maximum de part et d'autre de l 'origine.The slot F is equivalent in size to the width of the focusing spot of a laser beam, the dimensions of which are equal to or greater than the square of the wavelength of the laser beam. When the slot F moves, it occultly conceals a laser beam and the other. The two laser beams being in phase opposition and spatially shifted at the slot, the contribution of each laser beam to the total intensity at the exit of the slot can be determined. It can be shown that the intensity profile at the exit of the slot as a function of the position describes a Gaussian shape curve canceling at the origin of the abscissae and presenting a minimum and a maximum on both sides of the 'origin.
Grâce à ce profil d'intensité 21 et pour une fente F centrée sur l'axe 17 entre les deux faisceaux, un faible déplacement de la fente F selon la direction 18 générera une forte variation d'intensité. La sensibilité du dispositif ne dépend alors que de la pente à l 'origine de la répartition d'intensité, cette pente étant réglable en modifiant la focalisation des faisceaux et/ou la largeur de la fente. Le dispositif de positionnement par onde optique permet de positionner, par rapport à la partie optique OPT du dispositif et avec précision, un objet solidaire d'une fente F dont la petite largeur correspond à la direction de positionnement. Généralement, la masse de la fente F pourra être considérée comme négligeable devant la masse de l 'objet OBJ. En conséquence, la vitesse de réponse du système de positionnement par rapport aux mouvements de l'objet OBJ est rapide, rendant le dispositif de positionnement également adapté à la détection de position et de mouvements d'objets présentant des mouvements rapides, tels que des oscillations.
Comme on peut le voir sur les figures l a et Ib, Le dispositif de positionnement optique peut être décomposé en un bâti 16 et une partie optique OPT reliés par des fibres optiques. Le dispositif de positionnement optique présente ainsi la particularité de pouvoir fonctionner avec la partie optique OPT fonctionnant dans divers milieux comprenant notamment le vide et les liquides. La partie optique OPT étant reliée par des fibres optiques, sa localisation n'est limitée que par l 'absorption desdites fibres optiques due à la longueur desdites fibres optiques. On peut ainsi concevoir des applications en milieux hostiles, par exemple pour la mesure d' éléments ou de fissures dans le noyau d'une centrale nucléaire. La partie optique OPT ne présentant aucun système électrique ou électronique, elle ne présente aucune sensibilité aux ondes électromagnétiques, lui permettant de fonctionner dans des environnements difficiles, comme des centrales électriques, des radomes radar ou des atmosphères explosives.With this intensity profile 21 and for a slot F centered on the axis 17 between the two beams, a small displacement of the slot F in the direction 18 will generate a strong intensity variation. The sensitivity of the device then depends only on the slope at the origin of the intensity distribution, this slope being adjustable by modifying the focusing of the beams and / or the width of the slot. The optical wave positioning device makes it possible to position, relative to the optical part OPT of the device and with precision, an object integral with a slot F whose small width corresponds to the positioning direction. Generally, the mass of the slot F can be considered negligible compared to the mass of the OBJ object. Consequently, the speed of response of the positioning system with respect to the movements of the object OBJ is fast, making the positioning device also suitable for detecting the position and movements of objects presenting rapid movements, such as oscillations. . As can be seen in Figures 1a and 1b, the optical positioning device can be broken down into a frame 16 and an optical part OPT connected by optical fibers. The optical positioning device thus has the particularity of being able to operate with the OPT optical part operating in various media including vacuum and liquids. The optical portion OPT being connected by optical fibers, its location is limited only by the absorption of said optical fibers due to the length of said optical fibers. It is thus possible to design applications in hostile environments, for example for the measurement of elements or cracks in the nucleus of a nuclear power plant. The OPT optical part has no electrical or electronic system, it has no sensitivity to electromagnetic waves, allowing it to operate in harsh environments, such as power plants, radar radomes or explosive atmospheres.
Le dispositif de positionnement optique pourrait également trouver une application en sismologie ultrasensible, grâce à sa forte sensibilité, ou dans les application de métrologie en microscopie, comme la microscopie en champ proche. II peut être envisagé d' intégrer les différents éléments du dispositif par des techniques de microélectronique en utilisant par exemple des lasers de type VECSEL et des guides d'ondes pour remplacer les fibres optiques. De même, une grande partie voir la totalité de l'électronique de commande peut être intégrée permettant alors d' obtenir un dispositif de positionnement compact et d'une grande précision.The optical positioning device could also find an application in ultrasensitive seismology, thanks to its high sensitivity, or in the application of metrology in microscopy, such as near-field microscopy. It may be envisaged to integrate the various elements of the device by microelectronic techniques using, for example, VECSEL type lasers and waveguides to replace the optical fibers. Likewise, a large part of the totality of the control electronics can be integrated, making it possible to obtain a compact positioning device with a high degree of accuracy.
Il peut également être envisagé de réaliser un dispositif comprenant un nombre plus élevé de faisceaux laser. Par exemple quatre faisceaux laser pourraient permettre de contrôler le déplacement d'un objet selon deux directions distinctes. Dans ce cas, la fente serait remplacée par un trou, chaque paire de faisceaux permettant de déterminer le déplacement du trou selon une direction dans la limite du diamètre dudit trou.
Enfin, en vue de réduire les coûts, les fibres optiques pourraient être supprimées. Les faisceaux laser seraient directement collimatés en sortie du modulateur acousto-optique et la photodiode disposée directement en sortie du système optique. Cette approche pourrait également être combinée à l'utilisation de deux lasers à la place du modulateur acousto-optique comme décrit dans le mode de réalisation alternatif afin de réduire les coûts de façon encore plus drastique.
It may also be envisaged to provide a device comprising a higher number of laser beams. For example, four laser beams could control the movement of an object in two distinct directions. In this case, the slot would be replaced by a hole, each pair of beams to determine the displacement of the hole in a direction within the diameter of said hole. Finally, in order to reduce costs, optical fibers could be removed. The laser beams would be directly collimated at the output of the acousto-optic modulator and the photodiode disposed directly at the output of the optical system. This approach could also be combined with the use of two lasers instead of the acousto-optic modulator as described in the alternative embodiment to reduce costs even more drastically.
Claims
1. Dispositif de positionnement d'un objet par rapport à une position de référence, caractérisé par le fait qu' il comprend un laser (1 ), associé à un modulateur acousto-optique (3) pour émettre au moins deux faisceaux lasers parallèles et modulés en opposition de phase, lesdits faisceaux étant focalisés sur une fente (F) solidaire de l 'objet (OBJ) à positionner, le grand coté de ladite fente (F) étant perpendiculaire à la direction de positionnement, et une photodiode ( 13) adaptée pour collecter les faisceaux issus de la fente (F) et associée à un amplificateur à détection synchrone (9) pour délivrer un signal traduisant la position de la fente (F) par rapport à la position de référence.1. Device for positioning an object with respect to a reference position, characterized in that it comprises a laser (1) associated with an acousto-optical modulator (3) for emitting at least two parallel laser beams and modulated in phase opposition, said beams being focused on a slot (F) integral with the object (OBJ) to be positioned, the large side of said slot (F) being perpendicular to the positioning direction, and a photodiode (13) adapted to collect the beams from the slot (F) and associated with a synchronous detection amplifier (9) for providing a signal reflecting the position of the slot (F) relative to the reference position.
2. Dispositif de positionnement selon la revendication 1 comprenant un système optique apte à collimater, focaliser et collecter les faisceaux laser.2. Positioning device according to claim 1 comprising an optical system capable of collimating, focusing and collecting the laser beams.
3. Dispositif de positionnement selon la revendication 1 comprenant un générateur de fonction électrique (7) et un oscillateur (5), l 'oscillateur (5) émettant à sa sortie un signal radiofréquence présentant une modulation de fréquence comparable à la fréquence du signal électrique périodique émis par le générateur de fonction électrique (7), le signal périodique radiofréquence étant envoyé vers le modulateur acousto-optique (3) afin de commander la séparation des faisceaux laser. Positioning device according to claim 1 comprising an electric function generator (7) and an oscillator (5), the oscillator (5) emitting at its output a radio frequency signal having a frequency modulation comparable to the frequency of the electrical signal periodic signal emitted by the electrical function generator (7), the radio frequency periodic signal being sent to the acousto-optic modulator (3) to control the separation of the laser beams.
4. Dispositif de positionnement selon la revendication 3 dans lequel le signal électrique délivré par le générateur de fonction électrique (7) est un signal de référence pour l' amplificateur à détection synchrone (9).4. Positioning device according to claim 3 wherein the electrical signal delivered by the electrical function generator (7) is a reference signal for the synchronous detection amplifier (9).
5. Procédé de positionnement d'un objet par rapport à une position de référence dans lequel on détecte une variation de position d'un objet (OBJ) par rapport à une position de référence en fonction d'une variation d'intensité de deux faisceaux laser modulés en opposition de phase émergeants d'une fente solidaire de l'objet (OBJ) à positionner.5. Method for positioning an object with respect to a reference position in which a variation of position of an object (OBJ) relative to a reference position is detected as a function of a variation of intensity of two beams laser modulated in phase opposition emerging from a slot integral with the object (OBJ) to be positioned.
6. Procédé de positionnement selon la revendication 5 dans lequel on ajuste la sensibilité du dispositif en modifiant la largeur de la fente (F).6. Positioning method according to claim 5 wherein the sensitivity of the device is adjusted by changing the width of the slot (F).
7. Procédé de positionnement selon la revendication 5 dans lequel on détecte la variation d' intensité des faisceaux laser émergents de la fente (F) au moyen d'une photodiode ( 13).7. Positioning method according to claim 5 wherein the variation of intensity of the laser beams emerging from the slot (F) is detected by means of a photodiode (13).
8. Procédé de positionnement selon la revendication 7 dans lequel on obtient un signal de position par détection synchrone à partir du signal provenant de la photodiode (13) collectant les faisceaux lasers émergents.8. Positioning method according to claim 7 wherein a position signal is obtained by synchronous detection from the signal from the photodiode (13) collecting the emerging laser beams.
9. Procédé de positionnement selon la revendication 8 dans lequel on obtient un signal d' erreur en parallèle d'un signal de position après la détection synchrone. 9. Positioning method according to claim 8 wherein an error signal is obtained in parallel with a position signal after the synchronous detection.
Applications Claiming Priority (2)
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FR0753748A FR2913492B1 (en) | 2007-03-09 | 2007-03-09 | OPTICAL METROLOGY SYSTEM |
PCT/FR2008/050178 WO2008110721A2 (en) | 2007-03-09 | 2008-02-05 | Optical metrology system |
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EP2132522A2 true EP2132522A2 (en) | 2009-12-16 |
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EP08762037A Withdrawn EP2132522A2 (en) | 2007-03-09 | 2008-02-05 | Optical metrology system |
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EP (1) | EP2132522A2 (en) |
JP (1) | JP2010520994A (en) |
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AU (1) | AU2008224807A1 (en) |
CA (1) | CA2680015A1 (en) |
FR (1) | FR2913492B1 (en) |
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CN102680402B (en) * | 2011-11-15 | 2015-08-19 | 北京遥测技术研究所 | Quartz tuning fork strengthened photoacoustic spectrum gas cell |
CN103795367B (en) * | 2014-01-14 | 2016-06-01 | 北京航天时代光电科技有限公司 | The encapsulation device of a kind of enhancement type quartz tuning-fork |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3795449A (en) * | 1973-01-11 | 1974-03-05 | Lockheed Missiles Space | Cutter monitor |
US4834111A (en) * | 1987-01-12 | 1989-05-30 | The Trustees Of Columbia University In The City Of New York | Heterodyne interferometer |
KR940007618B1 (en) * | 1991-03-26 | 1994-08-22 | 가부시키가이샤 도시바 | Scanning optical system |
JP2792315B2 (en) * | 1992-03-10 | 1998-09-03 | 松下電器産業株式会社 | Birefringence measurement device |
EP0577088B2 (en) * | 1992-06-30 | 2010-10-20 | Canon Kabushiki Kaisha | Displacement information detection apparatus |
US5680111A (en) * | 1994-02-05 | 1997-10-21 | Baxter International Inc. | Dual sensor air-in-line detector |
US5867261A (en) * | 1997-04-28 | 1999-02-02 | International Business Machines Corporation | Surface inspection tool |
CN1260870A (en) * | 1998-04-17 | 2000-07-19 | 三菱电机株式会社 | Position detection apparatus |
US6496273B1 (en) * | 1999-05-05 | 2002-12-17 | Renishaw Plc | Position determining apparatus for coordinate positioning machine |
GB2357334A (en) * | 1999-12-15 | 2001-06-20 | Peter Bryan Webster | Opto-electronic position sensor |
US6947131B2 (en) * | 2002-05-07 | 2005-09-20 | Chf Solutions, Inc. | Blood leak detector for extracorporeal treatment system |
WO2003104767A2 (en) * | 2002-06-10 | 2003-12-18 | William Marsh Rice University | Quartz-enhanced photoacoustic spectroscopy |
JP2005069900A (en) * | 2003-08-25 | 2005-03-17 | Seiko Epson Corp | Focusing-point position detecting method, focusing-point position detector, droplet observing method, droplet observing device, and droplet discharging device |
EP1859252A1 (en) * | 2005-03-04 | 2007-11-28 | Koninklijke Philips Electronics N.V. | Photoacoustic spectroscopy detector and system |
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2007
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2008
- 2008-02-05 US US12/530,258 patent/US20100149552A1/en not_active Abandoned
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- 2008-02-05 AU AU2008224807A patent/AU2008224807A1/en not_active Abandoned
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US20100149552A1 (en) | 2010-06-17 |
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