EP0592631A1 - Phase detection deflectometer-type optical device having a large measuring range - Google Patents

Phase detection deflectometer-type optical device having a large measuring range

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Publication number
EP0592631A1
EP0592631A1 EP93907915A EP93907915A EP0592631A1 EP 0592631 A1 EP0592631 A1 EP 0592631A1 EP 93907915 A EP93907915 A EP 93907915A EP 93907915 A EP93907915 A EP 93907915A EP 0592631 A1 EP0592631 A1 EP 0592631A1
Authority
EP
European Patent Office
Prior art keywords
optical device
image
deflectometer
phase detection
ccd camera
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.)
Ceased
Application number
EP93907915A
Other languages
German (de)
French (fr)
Inventor
Jean-Marie Bacchus
Eric Durand
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.)
EssilorLuxottica SA
Original Assignee
Essilor International Compagnie Generale dOptique SA
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 Essilor International Compagnie Generale dOptique SA filed Critical Essilor International Compagnie Generale dOptique SA
Publication of EP0592631A1 publication Critical patent/EP0592631A1/en
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
    • G01M11/0257—Testing optical properties by measuring geometrical properties or aberrations by analyzing the image formed by the object to be tested
    • 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
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/255—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures for measuring radius of curvature
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/005—Testing of reflective surfaces, e.g. mirrors
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/0095—Relay lenses or rod lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G02B27/4233—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive element [DOE] contributing to a non-imaging application

Definitions

  • the invention relates to an optical device of the deflectometer type, in particular phase detection, with a large measurement range.
  • Document FR 2 647 913 describes an optical device, suitable for checking, by phase detection, any surface of an optical system, essentially comprising, along an optical path: emission means suitable for the constitution of a light source, a reflecting surface to be checked, a separating cube placed between the light source and the surface to be checked and provided with a semi-reflecting surface for deflecting the light beam reflected by the surface to be checked, a network such as a Ronchi grating, placed in the vicinity of the point of convergence of said reflected light beam, a lens for giving the image observable in the analysis plane of a camera with charge coupling device (CCD), that is to say say in the plane of the CCD sensor, and a camera coupled to computer processing means for the exploitation of the image by phase detection.
  • emission means suitable for the constitution of a light source
  • a reflecting surface to be checked a separating cube placed between the light source and the surface to be checked and provided with a semi-reflecting surface for deflecting the light beam reflected by the surface
  • This optical device of the deflectometer type, with phase detection, allows precise, rapid measurement, for the entire surface, and without contact, of a wide variety of spherical and aspherical surfaces, without specific tools.
  • it has limits in terms of the diameter of the measurable range, in particular due to the entrance pupil of its acquisition system.
  • An object of the invention is to increase the entrance pupil of an imaging system, in particular a deflectometer, in order to increase its measurable range.
  • Another object of the invention is to use a zoom for the observation of the image given by a deflectometer.
  • the subject of the invention is an optical device, of the deflectometer type, in particular with phase detection, comprising a light source, a surface to be checked, a semi-reflecting surface between the light source and the surface to be checked to deflect the reflected light beam.
  • a network placed in the vicinity of the point of convergence of said reflected light beam, and a CCD camera coupled to computer processing means, characterized in that it comprises, between the network and the CCD camera, a lens primary with large entrance pupil providing an intermediate image, a frosted surface intended to receive said intermediate image, and a secondary optical system taking up the intermediate image materialized on the frosted surface and forming a final image on the sensor of the CCD camera.
  • the secondary optical system is a zoom.
  • Fig. 1 a schematic view of an optical device of known type, with grating and separating element, for the control, by phase detection, of an optical surface;
  • Fig. 2 a diagram of the rays emitted by a light source and reflected by an aspherical optical surface
  • Fig. 3 a diagram illustrating the defocus with respect to the diagram in FIG. 2;
  • Fig. 4 a block diagram of the optical device of FIG. 1;
  • Fig. 5 a block diagram of the optical device according to the invention.
  • a light source 1 a semi-reflecting surface 2, the optical surface to be checked 3, a Ronchi grating 4, a lens 5, a sensor 6 of a CCD camera not shown, and the computing means 7 for processing.
  • the optical surface 3 being aspherical, a ray 8 from the source 1 reaches the surface 3 at point 9, and it is reflected at 10.
  • the ray 10 is deflected at 11 by the semi-reflecting surface 2, and it reaches the network 4 at a point 12 distant by a distance d from the point 13 symmetrical with the source 1 with respect to the semi-reflecting surface 2.
  • the distance d between the points 12 and 13 is the deflection undergone by the light ray coming from the source 1, after reflection on the surface 3 to be checked. For each point 9 of the surface 3, knowing the deflection d and the angle at which point 9 is seen from the source 1, makes it possible to know the slope at this point, and to reconstruct the surface 3 by integration.
  • optical network device and separating element for the phase detection control of an optical system is given in the document.
  • the objective 5 has the function of forming on the sensor 6 of the CCD camera, the image of the surface observed, on which is superimposed the pattern of fringes to be analyzed.
  • the illumination at a point on the surface is characteristic of the slope of the surface at this point.
  • the source 1 illuminates the surface 3, aspherical, the axis of which passes at points 1 and 15.
  • the diameter of the light beam reflected by the surface 3 is not no. This diameter is symbolized by the arrows 16 and 17.
  • a surface 3 will be measurable (pupillary imaging), if its CMD (possibly after recovery by an adaptation optic) is smaller in size than the pup i l l e input of the acquisition system.
  • the interest of the user is to have a system with the largest possible entrance pupil, if he wants to measure an area without specific asphericity compensation tools.
  • Fig. 4 the entrance pupil 14 and the circle of least diffusion 18 are shown.
  • the sensor 6, which defines the size of the image, is of small dimensions.
  • the entrance pupil 14 is of maximum size, and the opening is large on the image side.
  • the optical device according to the invention is schematically represented in FIG. 5.
  • the source 1 emits a beam towards the surface to be checked 3 which is aspherical.
  • the beam deflected by the surface 3, after defocusing, has a circle of least diffusion (CMD) 18.
  • CMD circle of least diffusion
  • the primary objective 19 has a large entrance pupil 14, but it has a relative aperture limited by the possibilities and production costs , and therefore it gives a great picture.
  • This image is materialized in the image plane of the primary objective 19, for example on a frosted surface 20, of small thickness.
  • This image is taken up by an optical system 21 for secondary imaging which forms an image thereof on the sensor 6 of the CCD camera.
  • the use of a frosted surface 20 between the primary objective 19 and the secondary optical system 21 makes it possible to resume the intermediate image, with the secondary optical system 21, at an opening angle ⁇ smaller than the opening angle image a of the primary objective 19.
  • the secondary objective is therefore no longer subjected to the proportionality relationship that exists, in conventional deflectometers, between the size of the entrance pupil and that of the image on the CCD camera sensor.
  • the size of the intermediate image can be very large, and the entrance pupil of the primary objective 19, that is to say in fact the entrance pupil of the optical acquisition system, can be greatly increased.
  • the secondary optical system 21 can be a zoom, because its opening is independent of that of the primary objective.
  • the optical device is applicable to systems for measuring surface areas by defectectometry. It essentially comprises a primary objective with a large entrance pupil forming an intermediate image materialized on a plane, for example with a frosted surface, and a secondary optical system for taking up the intermediate image, so that the size of the final image is compatible with any CCD camera sensor.

Abstract

Dispositif optique du type déflectomètre à détection de phase. Entre le réseau et la caméra CCD, un objectif primaire (19) à grande pupille d'entrée fournit une image intermédiaire sur un dépoli (20); et un système optique secondaire (21) reprend l'image intermédiaire et en forme une image finale sur le capteur (6) de la caméra CCD.Optical device of the phase detection deflectometer type. Between the network and the CCD camera, a primary objective (19) with a large entrance pupil provides an intermediate image on a frosted surface (20); and a secondary optical system (21) takes the intermediate image and forms a final image on the sensor (6) of the CCD camera.

Description

DISPOSITIF OPTIQUE DU TYPE DEFLECTOMETRE, NOTAMMENT A DETECTION DE PHASE, A GRAND DOMAINE DE MESURE  DEFLECTOMETER-TYPE OPTICAL DEVICE, IN PARTICULAR WITH PHASE DETECTION, WITH LARGE MEASUREMENT AREA
L'invention concerne un dispositif optique du type déflectomètre, notamment à détection de phase, à grand domaine de mesure. The invention relates to an optical device of the deflectometer type, in particular phase detection, with a large measurement range.
Les hautes technologies employées aujourd'hui dans de nombreux systèmes optiques ou mécaniques, nécessitent souvent des surfaces réalisées avec une précision submi cronique. En dehors de la maîtrise des procédés d'usinage, se pose le problême du contrôle de la qua l i té des composants obtenus.  The high technologies used today in many optical or mechanical systems often require surfaces produced with sub cronic precision. In addition to mastering the machining processes, there is the problem of controlling the quality of the components obtained.
Le document FR 2 647 913 décrit un dispositif optique, adapté au contrôle, par détection de phase, d'une surface quelconque d'un système optique, comportant essentiellement, suivant une voie optique : des moyens d'émission propres à la constitution d'une source lumineuse, une surface réfléchissante a contrôler, un cube séparateur placé entre la source lumineuse et la surface à contrôler et muni d'une surface semi-réfléchissante pour dévier le faisceau lumineux réfléchi par la surface à contrôler, un réseau tel qu'un réseau de Ronchi, placé au voisinage du point de convergence dudit faisceau lumineux réfléchi, un objectif pour donner l'image observable dans le plan d'analyse d'une caméra à dispositif de couplage de charge (CCD), c'est-à-dire dans le plan du capteur CCD, et une caméra couplée à des moyens informatiques de traitement pour l'exploitation de l'image par détection de phase.  Document FR 2 647 913 describes an optical device, suitable for checking, by phase detection, any surface of an optical system, essentially comprising, along an optical path: emission means suitable for the constitution of a light source, a reflecting surface to be checked, a separating cube placed between the light source and the surface to be checked and provided with a semi-reflecting surface for deflecting the light beam reflected by the surface to be checked, a network such as a Ronchi grating, placed in the vicinity of the point of convergence of said reflected light beam, a lens for giving the image observable in the analysis plane of a camera with charge coupling device (CCD), that is to say say in the plane of the CCD sensor, and a camera coupled to computer processing means for the exploitation of the image by phase detection.
Ce dispositif optique, du type déflectomètre, à détection de phase, permet une mesure précise, rapide, pour toute la surface, et sans contact, d'une grande variété de surfaces sphériques et asphériques, sans outillage spécifique. Il présente cependant, de par son principe, des limites en termes de diamètre du domaine mesurable, notamment en raison de la pupille d'entrée de son système d'acquisi tion. Un but de l'invention est d'augmenter la pupille d'entrée d'un système d'imagerie, notamment d'un déflectomètre, afin d'augmenter son domaine mesurable. This optical device, of the deflectometer type, with phase detection, allows precise, rapid measurement, for the entire surface, and without contact, of a wide variety of spherical and aspherical surfaces, without specific tools. However, in principle, it has limits in terms of the diameter of the measurable range, in particular due to the entrance pupil of its acquisition system. An object of the invention is to increase the entrance pupil of an imaging system, in particular a deflectometer, in order to increase its measurable range.
Un autre but de l'invention est d'utiliser un zoom pour l'observation de l'image donnée par un déflectomètre.  Another object of the invention is to use a zoom for the observation of the image given by a deflectometer.
L'invention a pour objet un dispositif optique, du type déflectomètre, notamment a détection de phase, comprenant une source lumineuse, une surface à contrôler, une surface semi-réfléchissante entre la source lumineuse et la surface à contrôler pour dévier le faisceau lumineux réfléchi par la surface à contrôler, un réseau placé au voisinage du point de convergence dudit faisceau lumineux réfléchi, et une caméra CCD couplée à des moyens informatiques de traitement, caractérisé en ce qu'il comporte, entre le réseau et la caméra CCD, un objectif primaire à grande pupille d'entrée fournissant une image intermédiaire, un dépoli destiné à recevoir ladite image intermédiaire, et un système optique secondaire reprenant l'image intermédiaire matérialisée sur le dépoli et en formant une image finale sur le capteur de la caméra CCD.  The subject of the invention is an optical device, of the deflectometer type, in particular with phase detection, comprising a light source, a surface to be checked, a semi-reflecting surface between the light source and the surface to be checked to deflect the reflected light beam. by the surface to be checked, a network placed in the vicinity of the point of convergence of said reflected light beam, and a CCD camera coupled to computer processing means, characterized in that it comprises, between the network and the CCD camera, a lens primary with large entrance pupil providing an intermediate image, a frosted surface intended to receive said intermediate image, and a secondary optical system taking up the intermediate image materialized on the frosted surface and forming a final image on the sensor of the CCD camera.
Selon Une autre caractéristique de l'invention, le système optique secondaire est un zoom.  According to another characteristic of the invention, the secondary optical system is a zoom.
D'autres caractéristiques ressortent de la description qui suit faite avec référence aux dessins annexés sur lesquels on peut voir :  Other characteristics appear from the following description made with reference to the accompanying drawings on which we can see:
Fig. 1 : une vue schématique d'un dispositif optique de type connu, à réseau et élément séparateur, pour le contrôle, par détection de phase, d'une surface optique ;  Fig. 1: a schematic view of an optical device of known type, with grating and separating element, for the control, by phase detection, of an optical surface;
Fig. 2 : un schéma des rayons émis par une source lumineuse et réfléchis par une surface optique asphérique ;  Fig. 2: a diagram of the rays emitted by a light source and reflected by an aspherical optical surface;
Fig. 3 : un schéma illustrant la défocalisation par rapport au schéma de la Fig. 2 ;  Fig. 3: a diagram illustrating the defocus with respect to the diagram in FIG. 2;
Fig. 4 : un schéma de principe du dispositif optique de la Fig. 1 ;  Fig. 4: a block diagram of the optical device of FIG. 1;
Fig. 5 : un schéma de principe du dispositif optique selon l'invention. Sur la fig 1 on peut voir une source lumineuse 1, une surface semi-refléchissante 2, la surface optique à contrôler 3, un réseau de Ronchi 4, un objectif 5, un capteur 6 d'une c am é r a CCD non représentée, et les moyens informatiques 7 de traitement. Fig. 5: a block diagram of the optical device according to the invention. In fig 1 we can see a light source 1, a semi-reflecting surface 2, the optical surface to be checked 3, a Ronchi grating 4, a lens 5, a sensor 6 of a CCD camera not shown, and the computing means 7 for processing.
La surface optique 3 étant asphérique, un rayon 8 issu de la source 1 atteint la surface 3 au point 9, et il est réfléchi en 10. Le rayon 10 est dévié en 11 par la surface semi-réfléchissante 2, et il atteint le réseau 4 en un point 12 éloigné d'une distance d du point 13 symétrique de la source 1 par rapport à la surface semi-réfléchissante 2.  The optical surface 3 being aspherical, a ray 8 from the source 1 reaches the surface 3 at point 9, and it is reflected at 10. The ray 10 is deflected at 11 by the semi-reflecting surface 2, and it reaches the network 4 at a point 12 distant by a distance d from the point 13 symmetrical with the source 1 with respect to the semi-reflecting surface 2.
La distance d entre les points 12 et 13 est la déflexion subie par le rayon lumineux issu de la source 1, après réflexion sur la surface 3 a contrôler. Pour chaque point 9 de la surface 3, la connaissance de la déflexion d et de l'angle sous lequel est vu le point 9 à partir de la source 1, permet de connaître la pente en ce point, et de reconstituer la surface 3 par intégration.  The distance d between the points 12 and 13 is the deflection undergone by the light ray coming from the source 1, after reflection on the surface 3 to be checked. For each point 9 of the surface 3, knowing the deflection d and the angle at which point 9 is seen from the source 1, makes it possible to know the slope at this point, and to reconstruct the surface 3 by integration.
II est alors possible de soustraire par calcul la surface théorique de la surface réelle et donc de présenter la carte des défauts de la surface 3.  It is then possible to subtract by calculation the theoretical surface from the real surface and therefore to present the defect map of surface 3.
Une description détaillée du dispositif optique à réseau et élément séparateur pour le contrôle par détection de phase d'un système optique, est donnée dans le document A detailed description of the optical network device and separating element for the phase detection control of an optical system is given in the document.
FR 2 647 913 précité, auquel il est fait référence, et qui fait partie intégrante de la présente description. FR 2 647 913 cited above, to which reference is made, and which forms an integral part of the present description.
Dans un tel dispositif (fig. 1), l'objectif 5 a pour fonction de former sur le capteur 6 de la caméra CCD, l'image de la surface observée, à laquelle est superposé le motif de franges à analyser. L'éclairement en un point de la surface est caractéristique de la pente de la surface en ce point.  In such a device (fig. 1), the objective 5 has the function of forming on the sensor 6 of the CCD camera, the image of the surface observed, on which is superimposed the pattern of fringes to be analyzed. The illumination at a point on the surface is characteristic of the slope of the surface at this point.
Par ailleurs, la surface observée 3 doit être placée, par rapport à l'objectif, de telle manière que tout point 9 renvoie à l'intérieur de la pupille d'entrée symbolisée en 14 de l'objectif 5, le rayon issu de la source 1 qu'il a défléchi. Si ce n'est pas le cas, le point considéré n'émettant pas de lumière vers la caméra, la mesure ne sera pas possible. La limite principale au domaine mesurable pour un dispositif du type "déflectomètre à détection de phase" est donc que tous les rayons issus de la source 1 doivent, après réflexion sur la surface 3, parvenir jusqu'au capteur 6 de la caméra d'acquisition, ou bien en d'autres termes entrer dans la pupille d'entrée 14 du système de formation des images (objectif + caméra). Furthermore, the observed surface 3 must be placed, with respect to the objective, in such a way that any point 9 returns to the interior of the entrance pupil symbolized at 14 of objective 5, the ray coming from the source 1 that he deflected. If this is not the case, the point considered not emitting light towards the camera, the measurement will not be possible. The main limit to the measurable range for a device of the "phase detection deflectometer" type is therefore that all the rays coming from the source 1 must, after reflection on the surface 3, reach the sensor 6 of the acquisition camera. , or in other words enter the entrance pupil 14 of the image formation system (lens + camera).
Sur la Fig. 2, la source 1 éclaire la surface 3, asphërique, dont l'axe passe aux points 1 et 15. Dans le plan perpendiculaire à cet axe et contenant la source 1, le diamètre du faisceau lumineux réfléchi par la surface 3 n'est pas nul. Ce diamètre est symbolisé par les flèches 16 et 17. De plus, il est possible de faire varier ce diamètre, et de le rendre minimal en déplaçant la source 1 par rapport à la surface 3 (Fig. 3).  In Fig. 2, the source 1 illuminates the surface 3, aspherical, the axis of which passes at points 1 and 15. In the plane perpendicular to this axis and containing the source 1, the diameter of the light beam reflected by the surface 3 is not no. This diameter is symbolized by the arrows 16 and 17. In addition, it is possible to vary this diameter, and to make it minimal by moving the source 1 relative to the surface 3 (Fig. 3).
Cette opération, couramment utilisée pour l'imagerie pupillaire, s'appelle la défocalisation. Elle permet de positionner toute surface asphérique par rapport à la source de manière à minimiser le diamètre du faisceau de retour dans le plan de la source. On parle alors de "cercle de moindre diffusion" (CMD) dans le plan de la source.  This operation, commonly used for pupillary imaging, is called defocus. It allows any aspherical surface to be positioned relative to the source so as to minimize the diameter of the return beam in the plane of the source. This is called the "least scattered circle" (CMD) in the source plane.
Un surface 3 sera mesurable (imagerie pupillaire), si son CMD (éventuellement après reprise par une optique d'adaptation) est inférieur en dimension à la pup i l l e d'entrée du système d'acquisition.  A surface 3 will be measurable (pupillary imaging), if its CMD (possibly after recovery by an adaptation optic) is smaller in size than the pup i l l e input of the acquisition system.
L'intérêt de l'utilisateur est d'avoir un système ayant la pupille d'entrée la plus grande possible, s'il veut mesurer une surface sans outillage spécifique de compensation d'asphêrici té.  The interest of the user is to have a system with the largest possible entrance pupil, if he wants to measure an area without specific asphericity compensation tools.
Pour augmenter cette taille de pupille, on peut : augmenter l'ouverture relative (F/D) de l'objectif, mais il est difficile et très coûteux de concevoir et réaliser des objectifs corrigés des aberrations pour les grandes ouvertures, augmenter sa focale, mais cela augmente proportionnellement la taille d'image. To increase this pupil size, we can: increase the relative aperture (F / D) of the objective, but it is difficult and very expensive to design and achieve objectives corrected for aberrations for large apertures, increase its focal length, but this proportionately increases the image size.
En pratique, cela signifie que la taille de la pupille d'entrée est directement proportionnelle à la taille de l'image formée.  In practice, this means that the size of the entrance pupil is directly proportional to the size of the image formed.
Les caméras CCD les plus courantes fonctionnent avec des capteurs dont la hauteur d'image est inférieure ou égale à 6.6 mm. Cette taille d'image permet déjà de mesurer un très large domaine de surfaces asphériques, notamment utilisées en optique. Par contre, pour des surfaces à déformations telles que le CMD sera supérieur à cette limite, on devra se limiter en termes de diamètre mesurable.  The most common CCD cameras work with sensors whose image height is less than or equal to 6.6 mm. This image size already makes it possible to measure a very wide range of aspherical surfaces, notably used in optics. On the other hand, for surfaces with deformations such that the CMD will be greater than this limit, one must limit oneself in terms of measurable diameter.
Enfin, ces notions de taille de pupille (plus la nécessité d'une pupille avant), avaient jusque là empêché l'emploi de zooms (difficultés d'étude et de réalisation).  Finally, these notions of pupil size (plus the need for a front pupil), had hitherto prevented the use of zoom lenses (difficulties of study and realization).
Sur la Fig. 4, la pupille d'entrée 14 et le cercle de moindre diffusion 18 sont représentés. Le capteur 6, qui définit la taille de l'image, est de petites dimensions. La pupille d'entrée 14 est de taille maximale, et l'ouverture est grande du côté image.  In Fig. 4, the entrance pupil 14 and the circle of least diffusion 18 are shown. The sensor 6, which defines the size of the image, is of small dimensions. The entrance pupil 14 is of maximum size, and the opening is large on the image side.
Pour éviter les contraintes des dispositifs existants, le dispositif optique selon l'invention est schématiquement représenté sur la Fig. 5. Sur cette Fig. 5, la source 1 émet un faisceau vers la surface à contrôler 3 qui est asphérique. Le faisceau défléchi par la surface 3, après défocalisation, présente un cercle de moindre diffusion (CMD) 18. L'objectif primaire 19 est à grande pupille d'entrée 14, mais il a une ouverture relative limitée par les possibilités et coûts de réalisation, et par conséquent, il donne une grande image. Cette image est matérialisée dans le plan image de l'objectif primaire 19, par exemple sur un dépoli 20, de faible épaisseur.  To avoid the constraints of existing devices, the optical device according to the invention is schematically represented in FIG. 5. In this Fig. 5, the source 1 emits a beam towards the surface to be checked 3 which is aspherical. The beam deflected by the surface 3, after defocusing, has a circle of least diffusion (CMD) 18. The primary objective 19 has a large entrance pupil 14, but it has a relative aperture limited by the possibilities and production costs , and therefore it gives a great picture. This image is materialized in the image plane of the primary objective 19, for example on a frosted surface 20, of small thickness.
Cette image est reprise par un système optique 21 d'imagerie secondaire qui en forme une image sur le capteur 6 de la caméra CCD.  This image is taken up by an optical system 21 for secondary imaging which forms an image thereof on the sensor 6 of the CCD camera.
L'utilisation d'un dépoli 20 entre l'objectif primaire 19 et le système optique secondaire 21 permet, de reprendre l'image intermédiaire, avec le système optique secondaire 21, sous un angle d'ouverture β plus faible que l'angle d'ouverture image a de l'objectif primaire 19. L'objectif secondaire n'est donc plus soumis à la relation de proportionnalité qui existe, dans les déflectomètres classiques, entre la taille de la pupille d'entrée et celle de l'image sur le capteur de la caméra CCD. De ce fait, la taille de l'image intermédiaire peut être très grande, et la pupille d'entrée de l'objectif primaire 19, c'est-à-dire en fait la pupille d'entrée du système optique d'acquisition, peut être largement augmentée. The use of a frosted surface 20 between the primary objective 19 and the secondary optical system 21 makes it possible to resume the intermediate image, with the secondary optical system 21, at an opening angle β smaller than the opening angle image a of the primary objective 19. The secondary objective is therefore no longer subjected to the proportionality relationship that exists, in conventional deflectometers, between the size of the entrance pupil and that of the image on the CCD camera sensor. As a result, the size of the intermediate image can be very large, and the entrance pupil of the primary objective 19, that is to say in fact the entrance pupil of the optical acquisition system, can be greatly increased.
En conséquence, le domaine mesurable, en termes de pente et d' asphéricité, du dispositif optique selon l'invention, se trouve augmenté par rapport aux déflectomètres classiques.  Consequently, the measurable range, in terms of slope and asphericity, of the optical device according to the invention is increased compared to conventional deflectometers.
Dans un dispositif optique selon l'invention, le système optique secondaire 21 peut être un zoom, car son ouverture est indépendante de celle de l'objectif primaire.  In an optical device according to the invention, the secondary optical system 21 can be a zoom, because its opening is independent of that of the primary objective.
Le dispositif optique selon l'invention est applicable à des systèmes de mesure de surfaces par déf1 ectomëtrië. Il comporte essentiellement un objectif primaire à grande pupille d'entrée formant une image intermédiaire matérialisée sur un plan, par exemple avec un dépoli, et un système optique secondaire pour reprendre l'image intermédiaire, de sorte que la taille de l'image finale soit compatible avec tout capteur de caméra CCD.  The optical device according to the invention is applicable to systems for measuring surface areas by defectectometry. It essentially comprises a primary objective with a large entrance pupil forming an intermediate image materialized on a plane, for example with a frosted surface, and a secondary optical system for taking up the intermediate image, so that the size of the final image is compatible with any CCD camera sensor.
Le dépoli peut être remplacé par tout type de diffuseur, c'est-à-dire une pièce optique qui, quand elle est éclairée par un rayon lumineux, rêêmet la lumière dans un cône présentant une certaine ouverture (indicatrice de diffusion).  The frosted can be replaced by any type of diffuser, that is to say an optical part which, when it is lit by a light ray, reflects the light in a cone having a certain opening (diffusion indicator).

Claims

REVEND I CATIONS  RESELL I CATIONS
1 Dispositif optique, du type déflectomètre, notamment à détection de phase, comprenant une source lumineuse, une surface à contrôler, une surface semi-réfléchissante entre la source lumineuse et la surface à contrôler pour dévier le faisceau lumineux réfléchi par la surface a contrôler, un réseau placé au voisinage du point de convergence dudit faisceau lumineux réfléchi, et une caméra CCD couplée à des moyens informatiques de traitement, caractérisé en ce qu'il comporte, entre le réseau et la caméra CCD, un objectif primaire (19) à grande pupille d'entrée fournissant une image intermédiaire, un dépoli (20) destiné à recevoir ladite image intermédiaire, et un système optique secondaire (21) reprenant l'image intermédiaire matérialisée sur le dépoli (20) et en formant une image finale sur le capteur (6) de la caméra CCD. 1 optical device, of the deflectometer type, in particular with phase detection, comprising a light source, a surface to be checked, a semi-reflecting surface between the light source and the surface to be checked in order to deflect the light beam reflected by the surface to be checked, a network placed in the vicinity of the point of convergence of said reflected light beam, and a CCD camera coupled to computer processing means, characterized in that it comprises, between the network and the CCD camera, a primary objective (19) with large entrance pupil providing an intermediate image, a frosted surface (20) intended to receive said intermediate image, and a secondary optical system (21) taking up the intermediate image materialized on the frosted surface (20) and forming a final image on the sensor (6) of the CCD camera.
2. Dispositif optique selon la revendication 1 caractérisé en ce que, le système optique secondaire est un zoom.  2. Optical device according to claim 1 characterized in that, the secondary optical system is a zoom.
EP93907915A 1992-04-01 1993-03-31 Phase detection deflectometer-type optical device having a large measuring range Ceased EP0592631A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9203937 1992-04-01
FR9203937A FR2689653B1 (en) 1992-04-01 1992-04-01 DEFLECTOMETER TYPE OPTICAL DEVICE, ESPECIALLY PHASE DETECTION, WITH LARGE MEASUREMENT AREA.
PCT/FR1993/000323 WO1993020416A1 (en) 1992-04-01 1993-03-31 Phase detection deflectometer-type optical device having a large measuring range

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EP0592631A1 true EP0592631A1 (en) 1994-04-20

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US (1) US5440383A (en)
EP (1) EP0592631A1 (en)
JP (1) JPH06508218A (en)
FR (1) FR2689653B1 (en)
WO (1) WO1993020416A1 (en)

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CN115655154B (en) * 2022-12-26 2023-03-10 常州微亿智造科技有限公司 High-resolution phase measurement deflection technique dynamic defect detection device and method

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FR2689653A1 (en) 1993-10-08
US5440383A (en) 1995-08-08
FR2689653B1 (en) 1994-05-20
WO1993020416A1 (en) 1993-10-14
JPH06508218A (en) 1994-09-14

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