Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
  • G02B26/10—Scanning systems
  • G02B26/12—Scanning systems using multifaceted mirrors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/08—Devices involving relative movement between laser beam and workpiece
  • B23K26/082—Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
  • B23K26/0821—Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head using multifaceted mirrors, e.g. polygonal mirror
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/08—Mirrors
  • G02B5/09—Multifaceted or polygonal mirrors, e.g. polygonal scanning mirrors; Fresnel mirrors
• • 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
  • G02B27/10—Beam splitting or combining systems
  • G02B27/106—Beam splitting or combining systems for splitting or combining a plurality of identical beams or images, e.g. image replication
• • 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
  • G02B27/10—Beam splitting or combining systems
  • G02B27/14—Beam splitting or combining systems operating by reflection only
  • G02B27/147—Beam splitting or combining systems operating by reflection only using averaging effects by spatially variable reflectivity on a microscopic level, e.g. polka dots, chequered or discontinuous patterns, or rapidly moving surfaces

Definitions

• the present invention relates to an optical system for a device for deflecting a light beam, a single or multiple deflection device comprising such an optical system, a marking installation comprising such a deflection device.
• the field of the invention is that of object marking installations.
• a deflection device consisting of a galvanometric head.
• a galvanometric head comprises a motor and a mirror mounted on the motor shaft.
• a source of illumination for example a laser beam generator, illuminates the mirror, and depending on the position of the mirror, the reflected light beam will illuminate a particular location of a target.
• the mirror is free to position itself over a wide angular range, whereas when a rapid change of position of the mirror is envisaged to illuminate another part of the target, it is necessary to print important angular accelerations and decelerations at the same time. mirror.
• Such a deflection device thus operates transiently, which is a handicap in the case where it is necessary to quickly change the point of impact of the reflected beam.
• An object of the present invention is to provide a deflection device which does not have the drawbacks of the prior art and which in particular makes it possible to rapidly modify the position of the point of impact of the light beam.
• an optical system comprising:
• a base intended to be mounted mobile in rotation about an axis of rotation, at least two reflecting elements secured to said base, each extending over an angular sector and taking the form of a cone portion of which axis coincides with said axis of rotation, at least two reflective elements have the same half-angle at the apex ⁇ , and of the at least two reflecting elements, at least two have different distances 'e', the distance 'e' being the distance measured parallel to the axis of rotation between an origin point of the axis of rotation and the vertex of the cone of the reflecting element.
• the optical system further comprises a shaping optics arranged downstream of the reflecting elements and intended to correct the aberrations of light beams from a reflection on said reflective elements.
• the invention also proposes a simple deflection device comprising an optical system according to one of the preceding variants, a motor on the shaft of which said optical system is fixed and comprising means for detecting the angular position of said shaft, a source of illumination providing a light beam for successively illuminating the reflective elements, and a control unit for collecting the data of the angular position detecting means and controlling the ignition and extinction of the incident light beam according to these data.
• the invention also proposes a multiple deflection device comprising:
• a first motor on the shaft of which said first optical system is fixed and comprising means for detecting the angular position of said shaft
• a second motor on the shaft of which said second optical system is fixed and comprising means for detecting the angular position of said shaft
• a light source delivering a light beam intended to illuminate successively the reflecting elements of said first optical system
• control unit intended to collect the data of each angular position detecting means and to control the ignition and extinction of the incident light beam according to these data
• the second optical system being arranged in such a way that the light beams reflected by the first optical system are reflected successively on the reflecting elements of said second optical system.
• the multiple deflection device further comprises, between the first optical system and the second optical system, an optical conjugation system for positioning the point of intersection of the light beams reflected by the first optical system on the axis of rotation. said second optical system.
• the optical conjugation system comprises means for transforming the plane containing the light beams reflected by the first optical system into another plane containing conjugated light beams, said other plane being perpendicular to the center plane of the reflective element of the second system. optical device on which they are intended to reflect and containing said point of intersection.
• the invention also proposes an object marking installation comprising:
• focusing means for focusing the light beams leaving the deflection device towards the object to be marked
• a scrolling device comprising a position detection means and intended to scroll the objects to be marked in front of the focusing means
• control unit provided for controlling the switching on and off of the incident light beam according to the position data collected from the angular position detection means of the deflection device and position data collected from the detection means of the deflection device; position of the scrolling device.
• FIG. 1 shows an optical system according to the invention
• FIG. 2a shows a section of the optical system of FIG. 1 according to a first variant
• FIG. 2b shows a section of the optical system of FIG. 1 according to a second variant
• FIG. 3 shows a multiple deflection device according to the invention.
• Fig. 1 shows an optical system 100 for a simple deflection device.
• the simple deflection device further comprises a motor on the shaft of which is fixed the optical system 100 which comprises a base 101 pierced at its center with a bore 102 which is here in the form of a D to fix the shaft of the engine.
• the base 101 is thus intended to be rotatably mounted around the axis of rotation D of the engine.
• On the edge of the base 101 are secured at least two elements 104, each extending over an angular sector. Of the angular sectors, some or all may be equal or they may all be different.
• joind includes both the fact that the base 101 and the elements 104 form a one-piece assembly, that the fact that the elements 104 are independent elements reported on the base 101.
• the simple deflection device further comprises a light source such as a laser beam generator delivering an incident light beam whose radius is very small compared to the dimensions of the angular sectors to limit the overlap of said light beam on two elements 104 .
• a light source such as a laser beam generator delivering an incident light beam whose radius is very small compared to the dimensions of the angular sectors to limit the overlap of said light beam on two elements 104 .
• the light beam will illuminate the elements 104 successively.
• the motor preferably a DC motor, comprises means for detecting the angular position of its shaft, such as for example an encoder. Knowing the position of the motor shaft makes it possible to know the position of the optical system 100 and the element 104 which is illuminated.
• Each element 104 takes the form of a cone portion whose axis coincides with the axis of rotation D and therefore the axis of rotation of the motor and the optical system 100.
• the surface which is illuminated by the source of each element 104 remains unchanged by rotation about the axis D.
• FIG. 2a and FIG. 2b show sections through a plane containing the axis D of the optical system 100.
• elements 104 At least two are reflective. Among the other elements 104, it is possible that some are transparent, some are reflective, some are neither reflective nor transparent.
• the elements referenced 104, 104a or 104b are reflective.
• the reflective elements 104 here all have the same lower surface 110 inscribed in a plane perpendicular to the axis of rotation D and which corresponds to the underside of the base 101.
• At least two elements 104 have the same half-angle at the vertex ⁇ , but each of these at least two elements 104 is defined by a distance 'e'.
• the distance 'e' is the distance measured parallel to the axis D between an origin point 'O' of the axis of rotation D and the vertex of the cone of the element 104.
• at least two among said at least two reflecting elements 104, at least two have different distances 'e'.
• the origin O is fixed arbitrarily along the axis of rotation D and the apex of the cone which is on the axis of rotation D is virtual because of the bore 102.
• the incident light beam 200 when the incident light beam 200 is emitted in a plane containing the axis of rotation D and encounters a particular element 104, it is reflected in a single direction despite the rotation of said element 104.
• the incident light beam 200 is reflected along N distinct directions 202.
• the arrow 202 in the solid line corresponds to the direction of reflection of the element 104 having a distance "e”
• the two arrows 202 in dashed lines correspond to reflection directions of elements 104 having distances e 'and e "different from e.
• the deflection device thus obtained makes it possible to obtain deflections of the incident light beam 200 at discrete angles, that is to say that the transition from one transmission angle to another is discontinuous.
• the reflective element 104 has a convex reflection surface
• the reflective element 104 has a concave reflection surface and the operation is similar to that of FIG. 2a.
• the optical system 100 may comprise only convex reflection surfaces, only concave reflection surfaces, or a mixture of both.
• the angular position of the optical system 100 thus determines the amplitude of the deflection of the incident light beam 200.
• this marking may be used in the context of laser marking of high-speed points on an object.
• the device of the state of the art Unlike the device of the state of the art, it is no longer necessary to accelerate or slow down the engine, and it operates in steady state, and just turn on or off the incident light beam 200 , for example via a flux modulator, depending on the position of the optical system 100 to illuminate such or that point of the target.
• the position of the optical system 100 is given by the means for detecting the angular position of the deflection device.
• the deflection device comprises a control unit intended to collect the data of the detection means and to control the ignition and extinction of the incident light beam as a function of these data and as a function of the point to be projected.
• the duration of switching from one reflection direction to another is independent of the amplitude of the angular deviation to be produced.
• the duration of the transition from one element 104 to another, when the optical system 100 is rotating, is independent of the corresponding elements 104.
• This duration is related to the rotational speed of the optical system 100, to the number of elements 104, to their respective angular width, to the diameter of the incident light beam 200 and to the distance between the point of impact of this incident light beam 200 on element 104 and the top of the cone.
• shaping optics can be set up to correct these aberrations downstream of the elements 104, and more particularly downstream of the reflection point. reflected light beam 202.
• Fig. 3 shows a multiple deflection device 300 according to the invention which makes it possible to project a matrix of points 302 in a plane 304.
• a matrix of points 302 For example, in the case of the marking of an object, it may be necessary to mark only certain points 302 of the matrix, and to modify, for each object, the points 302 to be marked.
• optical systems 100a and 100b as described above is particularly suitable for such an application, that is to say for switching at high frequency and at certain angles.
• the multiple deflection device 300 comprises:
• a first motor on the shaft of which the first optical system 100a is fixed and comprising means for detecting the angular position of the shaft
• a second optical system 100b as described above that is to say with at least two reflective elements 104b, a second motor on the shaft of which the second optical system 100b is fixed and comprising means for detecting the angular position of the shaft,
• a light source delivering a light beam for successively illuminating the elements 104a of the first optical system 100a due to the rotation of the latter;
• control unit intended to collect the data of each angular position detecting means and to control the ignition and extinction of the incident light beam according to these data
• the second optical system 100b being arranged in such a way that the light beams reflected by the first optical system 100a are reflected successively on the elements 104b of the second optical system 100b.
• the incident light beam intersecting the axis of rotation of the first optical system 100a is reflected on a particular element 104a of the first optical system 100a, and the distance 'e' of this particular element 104a, the reflected light beam is projected at a particular point of a particular element 104b of the second optical system 100b, and according to the distance 'e' of this element 104b, the thus reflected and outgoing light beam 306 illuminates a particular point 302 of the plane 304.
• the position of the point 302 thus marked depends on the half-angles at vertices ⁇ , and distances 'e' of the first optical system 100a and the second optical system 100b.
• the two optical systems 100a and 100b can be dedicated to the same marking direction or they can be dedicated to two marking directions. different.
• the multiple deflection device 300 further comprises, between the first optical system 100a and the second optical system 100b, a conjugation optical system 350.
• the general function of the optical conjugation system 350 is to conjugate the common origin of the light beams reflected by the first optical system 100a, that is to say the point of reflection on the first optical system 100a, with a point on the rotation axis of the second optical system 100b.
• the point corresponding to the intersection of the light beams from the optical conjugation system 350 (308) belongs to the axis of rotation of the second optical system 100b.
• the two optical systems 100a and 100b are arranged to perform deflections in two orthogonal planes in order to scan the matrix of points 302 in both directions.
• the first optical system 100a makes it possible to obtain a variation of the deviations in a first direction, here the horizontal direction H, and the second optical system 100b makes it possible to obtain a variation of the deviations in a second direction, here the vertical direction V.
• the optical conjugation system 350 changes the orientation of the light beams from the first optical system 100a before they are reflected on the second optical system 100b.
• the light beam is reflected at a particular angle.
• the light beams reflected by different elements 104a will propagate at different angles.
• each element 104a of the first optical system 100a determines the angular separation which separates these different reflections.
• the figure obtained is a series of aligned points 310.
• the plane P is here substantially the middle plane of the element 104a of the first optical system 100a illuminated by the incident beam.
• the light beams thus conjugated After passing through the optical conjugation system 350, the light beams thus conjugated have an orientation which is such that they are distributed in a plane perpendicular to the center plane of the element 104b of the second optical system 100b on which they are reflected.
• the optical conjugation system 350 thus comprises the means for transforming the plane P containing the light beams reflected by the first optical system 100a into another plane P 'containing the conjugated light beams, said other plane P' being perpendicular to the center plane of the 104b element of the second optical system 100b on which they are intended to reflect and containing the point intersection. This constitutes a particular function of the optical conjugation system 350 in this particular embodiment.
• the conjugated light beams 308 are thus all in the plane P 'and they have an angular distribution in this plane P' which causes a deflection in the horizontal direction of the target.
• each conjugated light beam 308 targets a particular column of the dot matrix 302.
• the conjugated light beam 308 is reflected on the element 104b of the second optical system 100b that is selected, causing a deviation similar to that generated by the first optical system 100a, i.e. a vertical deviation, which makes it possible to target a particular line of the particular targeted column, and consequently the point 302 corresponding to this line and this column.
• the lighting and extinction of the incident light beam is effected via an ignition and extinguishing device that the multiple deflection device 300 comprises for this purpose.
• an ignition and extinguishing device may be for example a flux modulator.
• Ignition and extinction of the incident light beam can illuminate all points 302 or only some of them.
• the multiple deflection device 300 of FIG. 3 makes it possible to generate a matrix of points 302 of dimensions K ⁇ L, where K corresponds to the number of elements 104a of the first optical system 100a and where L corresponds to the number of elements 104b of the second optical system 100b.
• the optical conjugation system 350 comprises a first plane mirror 352, a second mirror 354 and a focusing lens 356.
• the optical conjugation system 350 keeps the two optical systems 100a and 100b in the same plane and with parallel axes of rotation which facilitates the construction of the multiple deflection device 300.
• the focusing lens 356 makes it possible to focus the conjugate beams 308, derived therefrom, so that the point corresponding to the intersection of these conjugated light beams 308 belongs to the axis of rotation of the second optical system 100b.
• the two planar mirrors 352 and 354 make it possible to bring the light beams above the second optical system 100b and thus to bring the point of intersection above the second optical system 100b.
• the height at which the point of intersection is located is small as long as the conjugated light beams 308 are reflected on the second optical system 100b.
• the first mirror 352 is perpendicular to the plane P and has an inclination angle for directing the reflected light beams to a first direction which is here upward.
• the second mirror 354 has an orientation such that the light beams reflected by the first mirror 352 are directed towards the focusing lens 356.
• the two mirrors 352 and 354 thus realize a folding and a rotation of the light beams, that is to say that they make it possible to carry out the particular function described above.
• the bases of the optical systems 100a and 100b would then not be in the same plane. Indeed, the second optical system 100b would be placed in a position such that the deviations due to the first optical system 100a are in the plane P 'defined above with respect to the second optical system 100b.
• shaping optics 358 and 360 can be implemented downstream of the reflection points on the elements 104a and 104b of the two optical systems 100a and 100b.
• the second optical system 100b has L elements 104b, all having the same angular width, with L distances 'e' different, it has the fastest rotation speed and it controls the vertical defiexion.
• the first optical system 100a has K elements 104a, all having the same angular width, with K distances 'e' different and it controls the horizontal deflection.
• v r be the speed of rotation of the optical system 100b fast and vi the speed of rotation of the optical system 100a slow.
• the relation (1) corresponds to the fact that, when the optical system 100b fast describes a lathe, the optical system 100a slow turns by an angle equal to the angular width of one of its elements 104a. Due to rotation invariance, the reflection angle does not vary in the horizontal direction associated with the slow optical system 100a. In the plane of the array, the outgoing light beam 306 thus traverses all the points 302 of a particular column of the array.
• the outgoing light beam 310 traverses all the columns of the matrix, and therefore the entire matrix.
• the operation is analogous if the horizontal deflection is associated with the fast optical system 100b, and the vertical deflection with the optical system 100a slow.
• a fast 100b optical system lathe makes it possible to traverse a row of the matrix
• a slow optical system revolution 100a makes it possible to traverse the total matrix, but this time line by line.
• the optical system 100b fast has successively two identical series of elements 104b, each series having the same sequence of distances 'e'.
• the fast optical system 100b may have 2L elements 104b, divided into two identical series of L elements 104b at distances 'e' distinct. Then, with the same speed of rotation of the optical system 100b fast as in the previous case and doubling the speed of rotation of the optical system 100a slow compared to the previous case, the projection frequency of the matrix is doubled. Indeed, a revolution of the optical system 100b fast corresponds to the scrolling of two elements 104a of the optical system 100a slow, so the path of two rows or two columns of the matrix, according to the convention chosen.
• the multiple deflection device comprises two optical systems for the or each direction supporting the large dimension.
• a possible optical conjugation system can be set up between the two optical systems, but this optical conjugation system aims to achieve the general function described above, but in this particular embodiment, the optical conjugation system performs another particular function which consists only in a folding of the light beams and this folding is no longer combined with a rotation.
• the conjugation optical system keeps the light beams in a plane similar to the plane P but for the second optical system, that is to say containing the axis of rotation of said second optical system.
• the invention also provides a marking facility for marking objects.
• the marking facility includes:
• focusing means for focusing the light beams coming out of the deflection device towards the object to be marked
• a scrolling device comprising a position detection means and intended to scroll the objects to be marked in front of the focusing means
• control unit provided for controlling the switching on and off of the incident light beam according to the position data collected from the angular position detection means of the deflection device and position data collected from the detection means of the deflection device; position of the scrolling device.
• the deflection device includes a light source and an ignition and extinguishing device for turning on or off the incident light beam.
• the scrolling device is for example of the conveyor belt type, and is intended to scroll the objects to be marked in front of the focusing means so that it is marked by the outgoing and focused light beams.
• the deflection device may be simple as described on the basis of FIG. 1 or multiple like those described on the basis of FIG. 3.
• the position detection means of the scrolling device makes it possible to know which object is on said scrolling device and where it is with respect to the focusing means.
• the control unit then controls the ignition and extinguishing device according to the position data collected from the angular position detecting means of the deflection device and the position data collected from the position detecting means of the device. in order to control the ignition and extinction of the incident light beam as a function of the position of the or each optical system, because the corresponding point of the matrix must be marked or not and because of the presence of the object to be marked in front of the focusing means.
• the focusing means is for example an f-theta lens, designed to focus in a plane over the entire amplitude of the useful field. It is arranged so as to focus the beams on the surface of the objects that parade.
• one of the above optical systems can be replaced by a galvanometer head having a mirror 1308 and a motor on the shaft of which is fixed said mirror and means for detecting the angular position of said shaft.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Mechanical Engineering (AREA)
• Mechanical Optical Scanning Systems (AREA)

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• 2012
  • 2012-05-09 FR FR1254205A patent/FR2990523B1/fr not_active Expired - Fee Related
• 2013
  • 2013-05-07 EP EP13721728.7A patent/EP2847626A1/de not_active Withdrawn
  • 2013-05-07 WO PCT/EP2013/059536 patent/WO2013167622A1/fr active Application Filing

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