MODULAR DEFLECTION UNITS IN MIRROR SYMMETRICAL ARRANGEMENT

Abstract

The invention refers to a deflection module comprising a first deflection unit (10a) comprising a first scanning device (12a) for scanning a first working beam (50a) over a first working field and (40a) and a second deflection unit (10b) comprising a second scanning device (12b) for scanning a second working beam (50b) over a second working field (40b). At least a movable mirror (12a-2) of the first scanning device (12a) and at least a movable mirror (12b-2) of the second scanning device (12b) are arranged mirror-symmetrically with respect to each other. The first working field (40a) and the second working field (40b) overlap in a common overlap area (42).

Claims

1-29. (canceled)

30. A deflection module comprising: a first deflection unit comprising a first scanning device configured for scanning a first working beam over a first working field, wherein the first scanning device comprises: a first movable mirror for scanning the first working beam in a first direction by tilting around a first axis; and a second movable mirror for scanning the first working beam in a second direction by tilting around a second axis; a second deflection unit comprising a second scanning device configured for scanning a second working beam over a second working field; wherein the second scanning device comprises: a first movable mirror for scanning the second working beam in the first direction by tilting around a third axis; and a second movable mirror for scanning the second working beam in the second direction by tilting around a fourth axis; wherein the second movable mirror of the first scanning device and the second movable mirror of the second scanning device are arranged mirror-symmetrically with respect to each other and to a common plane of mirror symmetry , wherein the second axis is aligned with the fourth axis; and wherein the first working field and the second working field overlap in a common overlap area.

31. The deflection module of claim 30, wherein the first working beam is incident on the first scanning device propagating in a first incidence direction perpendicular to the common plane of mirror symmetry, and wherein the second working beam is incident on the second scanning device propagating in a second incidence direction perpendicular to the common plane of mirror symmetry, wherein the first incidence direction is aligned with and opposed to the second incidence direction.

32. The deflection module of claim 30, wherein the first deflection unit and the second deflection unit are arranged mirror-symmetrically with respect to the common plane of mirror symmetry, such that a beam path of the first working beam before being scanned by the first scanning device and a beam path of the second working beam before being scanned by the second scanning device are mirror symmetric with respect to each other and to the common plane of mirror symmetry.

33. The deflection module of claim 30, wherein a beam path of the first working beam before being scanned by the first scanning device is aligned with a beam path of the second working beam before being scanned by the first scanning device in a direction perpendicular to the common plane of mirror symmetry.

34. The deflection module of claim 30, wherein a separation between the second movable mirror of the first scanning device and the second movable mirror of the second scanning device corresponds to not more than ⅓ of a diameter of the second movable mirror of the first scanning device.

35. The deflection module of claim 30, wherein a distance between an optical centre of the second movable mirror of the first scanning device and an optical centre of the second movable mirror of the second scanning device corresponds to not more than 4 times an aperture of the first movable mirror of the first scanning device or of the first movable mirror of the second scanning device.

36. The deflection module of claim 35, wherein the first working beam is incident on the first scanning device having a first 1/e.sup.2 beam diameter, and wherein the second working beam is incident on the second scanning device having a second 1/e.sup.2 beam diameter, wherein the aperture of the first movable mirror of the first scanning device or of the first movable mirror of the second scanning device corresponds to at least 1.3 times the first 1/e.sup.2 beam diameter or the second 1/e.sup.2 beam diameter, respectively.

37. The deflection module of claim 30, wherein a distance between an optical centre of the second movable mirror of the first scanning device and an optical centre of the second movable mirror of the second scanning device is not more than 120 mm.

38. The deflection module of claim 30, wherein the first working field and the second working field are aligned with each other in a direction parallel to the common plane of mirror symmetry, and wherein the common overlap area has an extension in an overlap direction perpendicular to the common plane of mirror symmetry corresponding to at least 75% the extension covered by the first or second working field in the overlap direction.

39. The deflection module of claim 30, wherein the second movable mirror of the first scanning device is arranged along a beam path of the first working beam towards the first working field after the first movable mirror of the first scanning device, wherein the second movable mirror of the second scanning device is arranged along a beam path of the second working beam towards the second working field after the first movable mirror of the second scanning device, and wherein a height of the second movable mirror of the first scanning device over the first working field or a height of the second movable mirror of the second scanning device over the second working field is not more than 800 mm.

40. The deflection module of claim 30, further comprising a housing, wherein the first deflection unit and the second deflection unit are enclosed within the housing wherein the housing comprises a first transparent window configured for letting through the first working beam propagating from the first scanning device to the first working field and a second transparent window configured for letting through the second working beam propagating from the second scanning device to the second working field.

41. The deflection module of claim 40, wherein the first transparent window and the second transparent window are adjacent to each other or to the same lateral wall of the housing.

42. A modular deflection system comprising a first deflection module and a second deflection module, wherein each of the first deflection module and the second deflection module comprises: a first deflection unit comprising a first scanning device configured for scanning a first working beam over a first working field, wherein the first scanning device comprises: a first movable mirror for scanning the first working beam in a first direction by tilting around a first axis; and a second movable mirror for scanning the first working beam in a second direction by tilting around a second axis; a second deflection unit comprising a second scanning device configured for scanning a second working beam over a second working field; wherein the second scanning device comprises: a first movable mirror for scanning the second working beam in the first direction by tilting around a third axis; and a second movable mirror for scanning the second working beam in the second direction by tilting around a fourth axis; wherein the second movable mirror of the first scanning device and the second movable mirror of the second scanning device are arranged mirror-symmetrically with respect to each other and to a common plane of mirror symmetry, wherein the second axis is aligned with the fourth axis; and wherein the first working field and the second working field overlap in a common overlap area; wherein the first deflection module and the second deflection module are mutually attachable; wherein, when the first deflection module and the second deflection module are attached to each other, the common overlap area of the first deflection module and the common overlap area of the second deflection module overlap, thereby forming a common overlap field.

43. The modular deflection system of claim 42, wherein the first deflection module and the second deflection module are mirror symmetrical with respect to each other, when the first deflection module and the second deflection module are mutually attached.

44. The modular deflection system of claim 42, wherein a distance between an optical centre of the second movable mirror of the first scanning device of the first deflection module and an optical centre of the second movable mirror of the first or second scanning device of the second deflection module corresponds to not more than 4 times an aperture of the first movable mirror of the first scanning device of the first deflection module.

45. The modular deflection system of claim 42, wherein a distance between an optical centre of the second movable mirror of the first scanning device of the first deflection module and an optical centre of the second movable mirror of the first or second scanning device of the second deflection module is not more than 120 mm.

46. The modular deflection system of claim 43, wherein the first deflection module comprises a first housing, wherein the first deflection unit and the second deflection unit of the first deflection module are enclosed within the first housing; and wherein the second deflection module comprises a second housing, wherein the first deflection unit and the second deflection unit of the second deflection module are enclosed within the second housing; wherein the first housing and the second housing are mutually attachable in such a manner that the first housing and the second housing are arranged adjacent to each other, when the first deflection module and the second deflection module are attached to each other.

47. A deflection module comprising: a first deflection unit comprising a first scanning device configured for scanning a first working beam over a first working field, wherein the first scanning device comprises: a first movable mirror for scanning the first working beam in a first direction by tilting around a first axis; and a second movable mirror for scanning the first working beam in a second direction by tilting around a second axis; a second deflection unit comprising a second scanning device configured for scanning a second working beam over a second working field; wherein the second scanning device comprises: a first movable mirror for scanning the second working beam in the first direction by tilting around a third axis; and a second movable mirror for scanning the second working beam in the second direction by tilting around a fourth axis; wherein the second movable mirror of the first scanning device and the second movable mirror of the second scanning device are arranged mirror-symmetrically with respect to each other and to a common plane of mirror symmetry, wherein the second axis is aligned with the fourth axis; and wherein the first working field and the second working field overlap in a common overlap area; wherein the first scanning device further comprises a first galvanometer motor for tilting the second movable mirror of the first scanning device; wherein the second scanning device further comprises a second galvanometer motor for tilting the second movable mirror of the second scanning device; and wherein the first galvanometer motor and the second galvanometer motor are arranged on opposite sides of the respective second movable mirror with respect to the common plane of mirror symmetry, such that the first galvanometer motor and the second galvanometer motor are arranged mirror-symmetrically with respect to each other and to the common plane of mirror symmetry.

48. The deflection module of claim 47, wherein the second movable mirror of the first scanning device is arranged in a direction perpendicular to the common plane of mirror symmetry between the first galvanometer motor and the common plane of mirror symmetry, and wherein the second movable mirror of the second scanning device is arranged in a direction perpendicular to the common plane of mirror symmetry between the second galvanometer motor and the common plane of mirror symmetry.

49. The deflection module of claim 41, wherein the first transparent window and the second transparent window are integral with each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0087] FIG. 1 shows perspective view of the interior of a deflection module according to embodiments of the invention.

[0088] FIG. 2 shows a schematic top view of a deflection module like the deflection module of FIG. 1 according to some embodiments of the invention.

[0089] FIG. 3 shows a schematic side view of a deflection module like the deflection module of FIG. 1 according to some embodiments of the invention.

[0090] FIG. 4 shows a schematic illustration of the working fields and the common overlapping area of a deflection module according to some embodiments of the invention.

[0091] FIG. 5 is a schematic flow diagram of a method of laser processing a work piece according to some embodiments of the invention.

[0092] FIG. 6 shows schematic perspective views of the exterior of a deflection module according to some embodiments of the invention. FIG. 6a shows a superior perspective view and FIG. 6b shows an inferior perspective view.

[0093] FIG. 7 shows a schematic perspective view of the exterior of a modular deflection system according to some embodiments of the invention. FIG. 7a shows a superior perspective view and FIG. 7b shows an inferior perspective view.

[0094] FIG. 8 shows a schematic top view of the interior of a modular deflection system like the modular deflection system of FIG. 7 according to some embodiments of the invention.

[0095] FIG. 9 shows a schematic illustration of the working fields and the common overlap field of a modular deflection system like the modular deflection system of FIG. 7 according to some embodiments of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0096] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to a preferred embodiment illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated apparatus and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur now or in the future to one skilled in the art to which the invention relates.

[0097] FIG. 1 shows a schematic perspective view of the interior of a deflection module according to some embodiments of the invention, in particular of the optical components included therein. The first deflection module comprises a first deflection unit 10a and a second deflection unit 10b. The first deflection unit 10a comprises a first scanning device 12a, which comprises a first movable mirror 12a-1 and a second movable mirror 12a-2. FIG. 2 and FIG. 3 respectively show a top view and a side view of a deflection module according to embodiments of the invention like the deflection module shown in FIG. 1, wherein the same reference numerals are used for the same components. For the following description, FIGS. 1 to 3 may be considered in combination to the extent that they show the same components.

[0098] The first movable mirror 12a-1 is configured for scanning a first working beam 50a in a first direction, which in the embodiment shown in FIG. 1 corresponds to the x-direction, by tilting around a first axis A.sub.1, which in the embodiment shown in FIG. 1 is arranged with an inclination relative to the vertical z-direction of about 15°. The movement or tilting of the first movable mirror 12a-1 of the first deflection unit 10a is driven by a galvanometer motor 14a-1 that is arranged extending along the first axis A.sub.1, i.e. having a longitudinal axis corresponding to the largest dimension of the stepper motor 14a-1 extending along the first axis A.sub.1.

[0099] The second movable mirror 12a-2 is configured for scanning the first working beam 50a, after the first working beam 50a is reflected by the first movable mirror 12a-1, in a second direction, which in the embodiment shown in FIG. 1 corresponds to an y-direction perpendicular to the x- and z-directions, by tilting around a second axis A.sub.2, which in the embodiment shown in FIG. 1 is aligned with the x-direction. The movement or tilting of the second movable mirror 12a-2 of the first deflection unit 10a is driven by a galvanometer motor 14b-2 that is arranged extending substantially parallel to the second axis A.sub.2, i.e. substantially perpendicular to the common plane of mirror symmetry M.

[0100] The first movable mirror 12a-1 and the second movable mirror 12a-2 thus form an XY-scanning device configured for scanning the first working beam 50a in the x- and y-directions over a two-dimensional working field 40a. One or more workpieces or start materials located within the working field 40a can hence be laser-processed by the first working beam 50a deflected by the first deflection unit 10a.

[0101] The first working beam 50a is generated by a first laser source 28a that is optically connected to the first deflection unit 10a and/or, in some embodiments, integrated in the first deflection unit 10a. In the embodiment under consideration, the first laser source 28a is configured for generating laser light with a wavelength of 1070 nm forming the first working beam 50a.

[0102] After being generated by the first laser source 28a, the working beam 50a propagates through a first focusing device 20a that is configured for focusing, zooming and collimating the working beam 50a. The focusing device 20a comprises a first movable lens 22a, a second movable lens 24a and a fixed lens 26a, wherein the movable lenses 22a and 24a can be shifted in the z-direction for adjusting a variable focal length of the first focusing device 20a and for zooming and collimating the first working beam 50a, thereby adjusting, for example, a beam diameter of the first working beam 50a. The first lens 22a may be a fixed lens in other embodiments. The first focusing device 20a operates as a focusing and zooming unit setting the focal length of the entire optical system of the first deflection unit 10a such that the first working beam 50a is focused on the first working field 40a, at a distance SR from the second movable mirror 12a-2 (cf. FIG. 3).

[0103] After propagating through the first focusing device 20a, the first working beam 50a is reflected by a first optical element 16a, which in the embodiment shown in FIG. 1 is a dichroic mirror configured for reflecting light in a first wavelength range from 1020 nm to 1080 nm, such that the first working beam 50a is deflected from the z-direction from which it arrives from the first laser source 28a to the x-direction, towards the first scanning device 12a (cf. FIG. 3, showing a side view in the zx-plane corresponding to the perspective view of FIG. 1).

[0104] In the embodiments shown in FIGS. 1 to 3, the working beam 50a is generated by the first laser source 28a and fed into the first deflection unit in the vertical direction (in the z-direction). Therefore, the first optical element 16a is arranged at a 45° angle in the xz-plane with respect to each of the z- and x-directions (cf. FIG. 3). However, other configurations and corresponding arrangements of the first optical element 16a are possible. In other embodiments, the first working beam 50a may enter the first deflection units 10a in the horizontal x-direction or in a diagonal direction, for example a diagonal direction in the xz-plane, i.e. a direction having an x-component and a z-component, for instance at a 45° angle, although other angles are possible. The first optical element 16a may then be arranged at a corresponding angle for directing the first working beam 50a towards the first scanning device 12a, in particular towards the first movable mirror 12a-1. The same applies to the second deflection unit 10b (to be described in the following) with respect to the arrangement of the second laser source 28b and the second optical element 16b.

[0105] The deflection module further comprises a second deflection unit 10b having a structure, arrangement and optical components corresponding, possibly identical, to the components of the first deflection unit 10a. For example, the lenses 22b, 24b and 26b of the second focusing device 20b can be identical to the corresponding lenses 22a, 24a and 26a, respectively, of the first focusing device 20a. Likewise, the second optical element 16b of the second deflection unit 10b can be identical to the corresponding first optical element 16a of the first deflection unit 10a and be arranged accordingly to as to fulfil the same function. The second focusing device 20b operates as a focusing and zooming unit setting the focal length of the entire optical system of the second deflection unit 10b such that the second working beam 50b is focused on the second working field 40b, at a distance SR from the second movable mirror 12b-2 (cf. FIG. 3).

[0106] The second deflection unit 10a comprises a second scanning device 12b, which comprises a first movable mirror 12b-1 and a second movable mirror 12b-2, which respectively correspond in terms of function and structure to the first movable mirror 12a-1 and the second movable mirror 12a-2 of the first deflection unit 10a. The first movable mirror 12b-1 is configured for scanning a second working beam 50b, which is generated by a second laser source 28b that is functionally identical to the first laser source 28a, in the first direction (x-direction), by tilting around a third axis A.sub.3, which in the embodiment shown in FIG. 1 is parallel to the first axis A.sub.1, i.e. also arranged with respect to the vertical z-direction with an inclination of about 15°. The movement or tilting of the first movable mirror 12b-1 of the second deflection unit 10b is driven by a galvanometer stepper motor 14b-1 that is arranged extending along the first axis A.sub.3, corresponding to the galvanometer motor 14a-1.

[0107] The second movable mirror 12b-2 is configured for scanning the second working beam 50b, after the second working beam 50b is reflected by the second optical element 16b and the first movable mirror 12b-1, for scanning the second working beam 50b in the second direction (y-direction), by tilting around a fourth axis A.sub.4, which is aligned with the second axis A.sub.2 in the x-direction (cf. FIG. 2, showing a top view in the xy-plane corresponding to the perspective view of FIG. 1). The movement or tilting of the second movable mirror 12a-2 of the first deflection unit 10a is driven by a galvanometer motor 14b-2 that is arranged extending substantially parallel to the fourth axis A.sub.4 (and the second axis A.sub.2) and hence substantially perpendicular to the common plane of mirror symmetry M, corresponding to the galvanometer stepper motor 14a-2.

[0108] The first movable mirror 12b-1 and the second movable mirror 12b-2 form an XY-scanning device configured for scanning the second working beam 50b in the x- and y-directions over a two-dimensional working field 40b. One or more workpieces or start materials located within the working field 40b can hence be laser-processed by the second working beam 50b deflected by the second deflection unit 10b.

[0109] The first deflection unit 10a and the second deflection unit 10b are arranged mirror-symmetrically with respect to each other and with respect to a common plane of mirror symmetry M, which in FIG. 1 extends in the yz-plane, i.e perpendicular to the x-direction. As schematically seen in the top view of FIG. 2 and in the frontal view of FIG. 3, the beam path followed by the first working beam 50a before being scanned by the first scanning device 12a, i.e. between the first laser source 28a and the first scanning device 12a, is mirror symmetric, with respect to the common plane of mirror symmetry M, to the beam path followed by the second working beam 50b before being scanned by the second scanning device 12b, i.e. between the second laser source 28b and the second scanning device 12b. In the schematic views shown in FIGS. 1 to 3, the first working beam 50a, before being reflected by the first movable mirror 12a-1, is mirror symmetric to the second working beam 50b, before it is reflected by the first movable mirror 12b-1, and aligned therewith in the x-direction.

[0110] The portion of the first working beam 50a propagating in the z-direction from the first laser source 28a to the first optical element 16a propagates parallel to the portion of the second working beam 50b that propagates also in the z-direction from the second laser source 28b to the second optical element 16b. The portion of the first working beam 50a that propagates from the first optical element 16a to the first movable mirror 12a-1 and the portion of the second working beam 50b that propagates from the second optical element 16b to the first movable mirror 12b-1 propagate aligned with each other in the x-direction and directed towards each other, i.e. towards the common plane of mirror symmetry M.

[0111] The mirror symmetry between the first deflection unit 10a and the second deflection unit 10b with respect to the common plane of mirror symmetry M may be broken along the beam path followed, respectively, by the first working beam 50a and the second working beam 50b, from the corresponding scanning device 12a or 12b on, inasmuch as the movable mirrors 12a-1 and 12a-2 of the first scanning device 12a might be tilted at a given time differently than or without corresponding to a mirror-symmetric tilting state of the movable mirrors 12b-1 and 12b-2 of the second scanning device 12b, i.e. without corresponding to a specular image thereof with respect to the common plane of mirror symmetry M. However, the first movable mirror 12a-1 and the second movable mirror 12b-1 of the first scanning device 12a are, in their o-tilt positions, arranged, respectively, mirror-symmetrically with respect to the first movable mirror 12b-1 and the second movable mirror 12b-2 of the second scanning device 12b in their o-tilt positions.

[0112] Such mirror-symmetric arrangement of the first and second deflection units 10a and 10b allows for an arrangement of the first scanning device 12a and the second scanning device 12b, and in particular of the respective second movable mirrors 12a-2 and 12b-2, in which a distance d.sub.oc between the optical centre of the second movable mirror 12a-2 and the optical centre of the second movable mirror 12b-2 is reduced to a minimum. The second movable mirrors 12a-2 and 12b-2 are positioned very close to each other and are mutually separated in the x-direction by a small distance d. Consequently, the first working field 40a of the first deflection unit 10a and the second working field 40b of the second deflection unit 10b overlap with each other in at least a respective subregion thereof forming a common overlap area 42. The common overlap area 42 belongs both to the first working field 40a and to the second working field 40b.

[0113] In the embodiments illustrated in FIGS. 1 to 3, the movable mirrors 12a-1, 12a-2, 12b-1 and 12b-2 all have a polygonal shape configured to reflect a corresponding working beam having an 1/e.sup.2 diameter of up to 30 mm. The first and second working beams 50a and 50b have a Gauss-distributed intensity profile in their cross-sections and are incident on the first mirror 12a-1 of the first scanning device 12a and on the first mirror 12b-1 of the second scanning device 12b, respectively, having a first 1/e.sup.2 beam diameter of 20 mm. The first mirrors 12a-1 and 12b-1 are designed to have an aperture corresponding to 1.5 times the aforesaid 1/e.sup.2 beam diameter, i.e. an aperture of 30 mm, such that they can respectively reflect about 99.5% of the light of the first and second working beams 50a and 50b, respectively. The optical centres of the second movable mirrors 12a-2 and 12b-2 are separated from each other in the x-direction by the distance doc = 65 mm and the edges of the second movable mirrors 12a-2 and 12b-2 are separated from each other in the x-direction by the distance d = 5 mm.

[0114] As seen in FIG. 2, each of the second movable mirrors 12a-2 and 12b-2 is separated from the corresponding first movable mirror 12a-1 and 12b-1, respectively, in the y-direction. This separation does however not affect the separation d between the second movable mirrors 12a-2 and 12b-2.

[0115] The mirror-symmetric and aligned arrangement of the second movable mirrors 12a-2 and 12b-2 allows minimising the distance doz between the optical centres of the second movable mirrors 12a-2 and 12b-b, thereby increasing the size of the common overlap area 42 without having to increase a distance between each of the second movable mirrors 12a-2 and 12b-2 and the plane on which the first working field 40a and the second working field 40b (and hence the common overlap area 42) lie, i.e. without having to increase the scan radius..

[0116] As shown in FIG. 4, which shows a schematic view of the first working field 40a and the second working field 40b in the xy-plane, each of the first and second working fields 40a and 40b has a square shape with a side length L.sub.A = L.sub.B = 500 mm covering an area of 500 mm x 500 mm. The first working field 40a and the second working field 40b are aligned with each other in the y-direction: in the view illustrated in FIG. 4, the left edges of the first and second working fields 40a and 40b are aligned with each other in the y-direction and so are the corresponding right edges. Thus, in the y-direction the first and second working fields 40a and 40b have a 100% overlap. In the y-direction, the first working field 40a and the second working field 40b overlap over a distance of 500 mm. In the x-direction, the first and second working fields 40a and 40b partly overlap (81% overlap) over a distance L.sub.c = 435 mm. The common overlap area 42 hence covers an area of 500 mm x 435 mm.

[0117] Such large overlap of the first and second working fields 40a and 40b is compatible, thanks to the mirror-symmetric and aligned arrangement of the first and second deflection units 10a and 10b, and in particular of the second movable mirrors 12a-2 and 12b-2, with a rather small scan radius SR (cf. FIG. 3). In the embodiments considered in FIGS. 1 to 3, the scan radius is SR = 620 mm.

[0118] The galvanometer motors 14a-2 and 14b-2 for tilting the second movable mirrors 12a-2 and 12b-2 respectively, are arranged on opposite sides of the corresponding second movable mirror 12a-2, 12b-2: as seen in FIGS. 1 and 2, the second movable mirror 12a-2 is arranged between the common plane of mirror symmetry M and the stepper motor 14a-2. As seen in FIG. 2 in the xy-plane, the galvanometer motor 14a-2 is arranged to the left of the second movable mirror 12a-2. Likewise, the second movable mirror 12b-2 is arranged between the common plane of mirror symmetry M and the galvanometer motor 14b-2, such that, as seen in FIG. 2 in the xy-plane, the galvanometer motor 14b-2 is arranged to the right of the second movable mirror 12b-2. This configuration, with the galvanometer motors longitudinally extending in the x-direction perpendicular to the common plane of mirror symmetry M is space-saving and favours a reduced distance between the second movable mirrors 12a-2 and 12b-2 while avoiding any obstruction or collision between the stepper motors 14a-2 and 14b-2 and other components of the deflection module and also between the second movable mirrors 12a-2- and 12b-2.

[0119] The schematic view of FIG. 2 does not include the galvanometer motors associated to the first movable mirrors 12a-1 and 12b-1 for illustrative purposes. For the same reason, the schematic view of FIG. 3 does not include any of the galvanometer motors of the deflection module and only shows the first and second scanning devices as a schematic superposition of the corresponding movable mirrors 12a-1, 12a-2 and 12b-1, 12b-2, respectively.

[0120] As shown in FIG. 3, each of the first and second deflection units 10a and 10b further defines a corresponding detection beam path for a first detection beam 52a and a second detection beam 52b, respectively. The optical elements 16a and 16be, besides being reflective in the aforesaid wavelength range between 1000 nm and 1100 nm, have a high transmittance for wavelengths below 1000 nm and over 1100 nm. As a consequence, reflection light originated in the working fields, for example by a reflection of illumination light or of the light of the first and/or second working beams 50a, 50b, and reflected back by the scanning devices 12a and 12b are transmitted by the respective optical element 16a and 16b, such that the corresponding detection beams 52a and 52b propagate from the respective working field 40a and 40b to a respective detection device 70a, 70b that is configured for receiving and detecting the detection beams 52a and 52b for monitoring the laser processing by the corresponding deflection unit 10a or 10b. In the embodiment under consideration, the detection devices 70a and 70b each comprise a camera. Further, the first and second deflection units 10a and 10b each comprise a set of movable lenses 72a, 72b and fixed lenses 74a, 74b, respectively, for focusing the respective detection beam 52a and 52b on the corresponding detection device 70a, 70b for each position on the work fields 40a, 40b, from which reflection light might reach the detection devices 70a and 70b depending on the settings of the corresponding scanning devices 12a and 12b.

[0121] FIG. 5 is a flow diagram of a method 200 of laser processing one or more workpieces using a deflection module like the deflection module described with respect to FIGS. 1 to 3 above. The workpiece can be formed from a basis material such as metal powder by laser-processing successive layers of the basis material within the common overlap area 42 using the first deflection unit 10a and the second deflection unit 10b of the deflection unit.

[0122] In the method 200, the first deflection unit 10a of the deflection module is used for scanning the working beam 50a, which is generated as a laser beam with a first power density of 4 MW/cm.sup.2, and the second deflection unit 10b of the deflection module is used for scanning the working beam 50b, which is generated as a laser beam with a second power density of 40 MW/cm.sup.2. The first working beam 50a and the second working beam 50b may be generated by identical laser sources having the same beam power. The higher power density of the second working beam is implemented by configuring the second working beam 50b having a smaller spot size than the first working beam 50a.

[0123] The first working beam 50a is used for warming up the basis material and the second working beam 50b is subsequently used for laser-processing the basis material at points at which the basis material has previously been warmed up by the first working beam 50a. The first and second working beams 50a and 50b can operate simultaneously, such that the first working beam 50a goes on to warm up other points of the basis material while the second working beam 50b is laser-processing points of the basis material already warmed-up by the first working beam 50a.

[0124] For each layer of basis material to be laser-processed, at given points of the basis material, the first working beam 50a is first used, at 202, for warming up the basis material. Then, at 204, the second working beam 50b is used at the same points of the basis material for laser-processing the warmed-up basis material.

[0125] In other embodiments (not shown), the first working beam 50a can further be employed for slowing down the cooling-off of points of the basis material that have previously been laser-processed by the second working beam 50b.

[0126] If more than one deflection modules are combined for cooperative operation (see description of FIG. 7 to below), there are more than two working beams available, for which more than one working beams, for example two, can be used in 202 to warm up and/or cool down the basis material and more than one working beam, for example two, can be used in 204 to laser-process points of the basis material already warmed-up or to be cooled-down by the other working beams.

[0127] FIG. 6 schematically illustrates two different perspective exterior views of a deflection module according to embodiments of the invention, comprising a first deflection unit 10a and a second deflection unit 10b as described for the embodiments shown in FIGS. 1 to 3. As seen in FIG. 6, the deflection module comprises a housing 60. All optical components described with respect to FIGS. 1 to 3, with the exception of the laser sources 28a and 28b, are housed within the housing 60, in the arrangement illustrated in FIGS. 1 to 3, wherein the longitudinal direction of the housing 60, i.e. the direction in which the housing 60 extends longest, corresponds to the x-direction. In the embodiment shown in FIG. 6, the housing 60 comprises an optical inlet 68a, 68b in the form of an optical connector for receiving a laser source like the laser sources 28a and 28b described for FIGS. 1 to 3, wherein, when the laser source is coupled to the optical inlet 68a, 68b, the laser source is arranged in a diagonal position in the xz-plane, forming a 30° angle with respect to each of the z- and x-axes. Thus, in the embodiments considered in FIG. 6, the laser light generated by the laser sources enters the deflection module in such diagonal direction.

[0128] The housing 60 is waterproof and dustproof and implements IP64 sealing protection according to the International Protection Rating, such that the interior thereof is isolated from the outside environment of the housing 60 due to the sealing effect provided by the housing 60.

[0129] The housing 60 comprises a first transparent window 62a and a second transparent window 62b, which are respectively formed by glass plates arranged at the bottom of the housing 60, as shown in FIG. 6b. The first transparent window 62a is arranged below the second movable mirror 12a-2 of the first scanning device 12a of the first deflection module 10a, aligned with the second movable mirror 12a-2 in the xy-plane (cf. FIGS. 1 to 3), at a distance of about 55 mm from the second movable mirror 12a-2 in the z-direction, such that the first working beam 50a can be transmitted through the first transparent window 62a for any targeted point of the first working field 40a, i.e. for any deflection setting of the first scanning device 12a. Likewise, the second transparent window 62b is arranged below the second movable mirror 12b-2 of the second scanning device 12b of the second deflection module 10b, aligned with the second movable mirror 12b-2 in the xy-plane (cf. FIGS. 1 to 3), at a distance of about 55 mm from the second movable mirror 12b-2 in the z-direction, such that the second working beam 50b can be transmitted through the second transparent window 62b for any targeted point of the second working field 40b, i.e. for any deflection setting of the second scanning device 12b.

[0130] The first transparent window 62a and the second transparent window 62b are arranged adjacent to each other, such that they share a common edge 65. In the embodiment shown in FIG. 6, the first transparent window 62a and the second transparent window 62b are formed by independent glass plates. However, in other embodiments, the first transparent window 62a and the second transparent window 62b may be integral with each other and a single glass plate may cover both the first and second transparent windows 62a and 62b.

[0131] As seen in FIG. 6, the first transparent window 62a and the second transparent window 62b are arranged adjacent to a lateral wall 63 of the housing 60 instead of being arranged in the middle of the bottom part of the housing or centred in the y-direction. In other words, the first and second transparent windows are not arranged at equal distances from the lateral wall 63 of the housing and the opposite lateral wall of the housing. As shown in FIG. 7, this allows mutually attaching two deflection modules 102, 104 like the deflection modules illustrated in FIGS. 1 to 3 (interior views) and 6 (exterior view) to form a modular deflection system having a minimal distance between the transparent windows 62a and 62b of a first housing 60a of a first deflection module and the corresponding transparent windows 62c and 62d of a second housing 60b of a second deflection module. FIGS. 7a and 7b respectively show perspective views from different angles of a first deflection module 102 and a second deflection module 104, which are removably attached to each other forming a modular deflection system.

[0132] As seen in FIG. 7b, since the transparent windows 62a and 62b of the first deflection module 102 and the transparent windows 62c and 62d of the second deflection module 104 are arranged offset from a central position with respect to the longitudinal axis of the respective deflection module, without being equidistant with respect to opposing lateral walls of the respective housings 60a and 60b, when the first and second deflection modules 102, 104 are attached together, the transparent windows 62a and 62b of the first housing 60a are adjacent, respectively, to the transparent windows 62c and 62d of the second housing 60b. The housings 60a and 60b comprise an attachment mechanism (not shown) for detachably or removably attaching the first and second deflection modules 102, 104 to each other.

[0133] FIG. 8 shows a schematic front view of the interior of the modular deflection system shown in FIG. 7 when the first deflection module 102 and the second deflection module 104 are mutually attached. Each of the first and second deflection modules 102 and 104 corresponds to a deflection module like reflection module described with respect to FIGS. 1 to 3, comprising the same components in a corresponding arrangement. Thus, FIG. 8 corresponds to a doubling of the schematic top view of FIG. 2. The first deflection module 102 and the second deflection module 104 are arranged mirror symmetrical with respect to each other and with respect to a further plane of mirror symmetry O that is indicated in FIG. 8.

[0134] Due to the symmetric arrangement of each of the first and second deflection modules 102 and 104, wherein the first deflection module 102 defines a first common plane of mirror symmetry M1 corresponding to the plane M in FIGS. 1 to 3 and the second deflection module 104 defines a second common plane of mirror symmetry M2 corresponding to the plane M in FIGS. 1 to 3, and due to the arrangement of the respective second movable mirrors 12a-2, 12b-2, 12C-2 and 12d-2, which are arranged adjacent to one of the lateral edges of the respective deflection module (corresponding to the arrangement of the transparent windows 62a-62d described with respect to FIG. 7), the separation between each two of the second movable mirrors 12a-2, 12b-2, 12C-2 and 12d-2 is reduced to a minimum. The separation between the second movable mirrors 12a-2 and 12b-2 of the first deflection module 102 and between the second movable mirrors 12C-2 and 12d-2 of the second deflection module 104 as well as the separation distances between the respective optical centres thereof correspond to the separations distances d, doc that have been described for FIGS. 1 to 3.

[0135] Further, the separation d′ between the second movable mirror 12a-2 of the first scanning device 12a of the first deflection module 102 and the second movable mirror 12C-2 of the first scanning device 12C of the second deflection module 104 and between the second movable mirror 12b-2 of the second scanning device 12b of the first deflection module 102 and the second movable mirror 12d-2 of the second scanning device 12d of the second deflection module 104 is of about 10 mm. The distance d′.sub.oc between the optical centre of the second movable mirror 12a-2 of the first scanning device 12a of the first deflection module 102 and the optical centre of the second movable mirror 12C-2 of the first scanning device 12C of the second deflection module 104 and between the optical centre of the second movable mirror 12b-2 of the second scanning device 12b of the first deflection module 102 and the optical centre of the second movable mirror 12d-2 of the second scanning device 12d of the second deflection module 104 is of about 65 mm.

[0136] As a consequence, the size of a common overlap field 44, in which the working field 40a of the first deflection unit 10a of the first deflection module 102, the working field 40b of the second deflection unit 10b of the first deflection module 102, the working field 40c of the first deflection unit 10c of the second deflection module 104, and the working field 40d of the second deflection unit 10d of the second deflection module 104 overlap as shown in FIG. 9 can be increased for a given scan radius.

[0137] In the embodiment illustrated in FIG. 9, each of the working fields 40a, 40b, 40c and 40d is a square field covering an area of 500 mm x 500 mm. The first and second working fields 40a and 40b of the first deflection module 102 are aligned with each other in a first overlap direction (the x-direction). The first and second working fields 40c and 40d of the second deflection module 104 are likewise aligned with each other in the first overlap direction (the x-direction). The first and second working fields 40a and 40b of the first deflection module 102 and the first and second working fields 40c and 40d of the second deflection module 104 overlap with each other in the first overlap direction to 87%, i.e. for a length of 435 mm. Further, the first working fields 40a and 40c and the second working fields 40b and 40d overlap with each other, respectively, in a second overlap direction (the y-direction) to 87%, i.e. for a length of 435 mm. Thus the common overlap field 44 covers an area of 435 mm x 435 mm, while the scan radius between each of the second movable mirrors 12a-2, 12b-2, 12C-2 and 12d-2 (in their respective o-tilt positions) and the plane of the working fields 40a, 40b, 40c and 40d is of 620 mm.

[0138] Although preferred exemplary embodiments are shown and specified in detail in the drawings and the preceding specification, these should be viewed as purely exemplary and not as limiting the invention. It is noted in this regard that only the preferred exemplary embodiments are shown and specified, and all variations and modifications should be protected that presently or in the future lie within the scope of protection of the invention as defined in the claims.