Optical device for a micro-machining system and micro-machining method

Abstract

The invention relates to an optical device (10) for a laser micro-machining system, the device comprising: an optical axis (16), a collimating member (20) on the optical axis (16), a diffractive optical element (18) on the optical axis upstream of the collimating member (20), the diffractive optical element being capable of dividing a non-collimated laser beam propagating along the optical axis into a plurality of sub-beams, and the diffractive optical element being movable relative to the collimating member (20), the displacement of the diffractive optical element (18) relative to the collimating member being capable of varying the angle between the sub-beams downstream of the collimating member, while maintaining the shape and size of the sub-beams. The invention further relates to a micro-machining system and to a micro-machining method.

Description

[0001] Optical device for a micromachining system and micromachining method

[0002] Technical field

[0003] The present invention relates to an optical device for a laser micromachining system, a micromachining system and a micromachining method.

[0004] Prior art

[0005] There are prior art devices for dividing a laser beam into sub-beams for the purpose of micromachining a part. However, the disadvantage of these devices is that the resulting sub-beams are complex to adjust.

[0006] There is a need for a device for splitting a laser beam into sub-beams that is simple to adjust.

[0007] Statement of the invention

[0008] To this end, the invention proposes an optical device for a laser micromachining system, the device comprising an optical axis, a collimation member on the optical axis, a diffractive optical element on the optical axis upstream of the collimation member, the diffractive optical element being capable of dividing a non-collimated laser beam propagating along the optical axis into a plurality of sub-beams and being movable relative to the collimation member, the movement of the diffractive optical element relative to the collimation member being capable of varying the angle between the sub-beams downstream of the collimation member, while maintaining the shape and size of the sub-beams. In particular, this is a movement towards or away from the diffractive optical element relative to the collimation member.

[0009] According to a variant, the movement of the diffractive optical element is motorized. The movement is linear.

[0010] According to one variant, the diffractive optical element is a passive element.

[0011] According to a variant, the device further comprises one or more non-collimation members putting the laser beam propagating towards the diffractive optical element into a non-collimated state, the non-collimation members being on the optical axis upstream of the diffractive optical element and being arranged in such a way that the sub-beams downstream of the collimation member have a size less than, equal to or greater than the size of the laser beam upstream of the device.

[0012] According to a variant, one of the non-collimation members is capable of making the laser beam converge, such that the sub-beams downstream of the collimation member have a size smaller than the size of the beam upstream of the device.

[0013] According to a variant, one of the non-collimation members is capable of making the laser beam diverge, such that the sub-beams downstream of the collimation member have a size greater than the size of the beam upstream of the device.

[0014] According to a variant, a first non-collimation member among the non-collimation members is capable of making the laser beam diverge, a second non-collimation member among the non-collimation members is capable of making the laser beam converge, such that the sub-beams downstream of the collimation member have a size equal to the size of the beam upstream of the device.

[0015] According to a variant, the displacement of the diffractive optical element relative to the collimation member is capable of varying the angle between the sub-beams while allowing conservation of at least one of the characteristics among the polarization, the wavelength and the duration of the pulses of the sub-beams and while allowing conservation of at least one of the characteristics among the polarization, the wavelength and the duration of the pulses of a laser beam upstream of the device in the sub-beams.

[0016] According to one variant, the device further comprises, downstream of the collimation member, an assembly of optical elements capable of modifying the characteristics of the sub-beams.

[0017] According to a variant, the movement towards or away from the diffractive optical element relative to the collimation member is capable of varying the angle between the sub-beams downstream of the collimation member, while maintaining the collimation of the sub-beams.

[0018] The invention also relates to a system for micromachining one or more parts, comprising: a device as described previously and a laser capable of emitting a laser beam along the optical axis.

[0019] According to one variant, the system further comprises, downstream of the device, a scanner head and a focusing element.

[0020] The invention also relates to a method for micromachining one or more parts, comprising the steps of: Providing a system as described above, Providing one or more parts to be machined, the part(s) being downstream of the system, Varying the angle between the sub-beams by moving the diffractive optical element towards or away from the collimation member, the sub-beams retaining their shape and size regardless of the angle between the sub-beams and their spacing on the part(s) to be machined, Machining the part(s) with the sub-beams.

[0021] The use in this document of the verb "to understand", its variants, as well as its conjugations, cannot in any way exclude the presence of elements other than those mentioned. The use in this document of the indefinite article "un", "une", or of the definite article "le", "la" or "I'", to introduce an element does not exclude the presence of a plurality of these elements.

[0022] The terms "first", "second", "third", etc. are used in this document exclusively to differentiate between different elements, without implying any order between these elements.

[0023] All of the preferred embodiments and all of the advantages of the device are transposed mutatis mutandis to the present system and method, and vice versa. The different embodiments can be considered alone or in combination. Brief description of the figures

[0024] Other characteristics and advantages of the present invention will appear on reading the detailed description which follows, for the understanding of which reference will be made to the appended figures which show:

[0025] - figure 1, a schematic view of a device and a system according to one embodiment;

[0026] - figure 2, a schematic view of a device according to one embodiment;

[0027] - figure 3, a schematic view of the device according to figure 2, in another operating state;

[0028] - figure 4, a schematic view of a device according to one embodiment;

[0029] - figure 5, a schematic view of the device according to figure 4, in another operating state;

[0030] - figure 6, a schematic view of the device according to one embodiment.

[0031] The drawings of the figures are not to scale. Like elements are generally denoted by like references in the figures. For the purposes of this document, identical or similar elements may bear the same references. Furthermore, the presence of reference numbers or letters in the drawings cannot be considered as limiting, including when these numbers or letters are indicated in the claims.

[0032] Detailed description of embodiments of the invention

[0033] An optical device for a laser micromachining system is provided. The device comprises an optical axis, a collimating member on the optical axis, and a diffractive optical element on the optical axis upstream of the collimating member. The diffractive optical element is capable of splitting a non-collimated laser beam propagating along the optical axis into a plurality of sub-beams, the diffractive optical element being movable relative to the collimating member. The movement of the diffractive optical element relative to the collimating member is capable of varying the angle between the sub-beams downstream of the collimating member, while maintaining the shape and size of the sub-beams. The device makes it possible to obtain sub-beams that maintain certain characteristics identically even when the spacing of the sub-beams changes. This allows working in different machining conditions, while maintaining these characteristics.The device is easy to set up. The device is also quick to set up.

[0034] Figure 1 illustrates a schematic view of a device 10 and a system 50 according to one embodiment. The system 50 is a system for laser micromachining of a part 12 or several parts 12 (at least one part 12). Subsequently, the reference to a part is made in a non-limiting manner. Similarly, the reference to machining or micromachining designates the same operation of processing a part.

[0035] The system 50 comprises a laser 14 emitting a beam (or laser beam) along an optical axis 16. The laser beam emitted by the laser 14 may be a non-collimated laser beam (for example when the laser 14 is of the fiber head type) or may be a collimated laser beam. By collimated laser beam is meant a light whose radiations are parallel or almost parallel. By non-collimated laser beam is meant a light whose radiations are not parallel. In the following, the terms “upstream” and “downstream” designate positions along the optical axis 16, in the direction of propagation of the laser beam along the optical axis 16. In the figures, the direction of propagation of the laser is from left to right.

[0036] The optical axis 16 is the axis along which the laser beam emitted by the laser 14 is likely to propagate. The optical axis 16 is shown as being rectilinear in the figures, by way of example. The optical axis 16 may undergo variations in direction. In other words, the part 12 is opposite the laser 14 in Figure 1 but may be in another position by deflection of the beam emanating from the laser 14. The device 10 may also comprise a collimation member 20 on the optical axis 16. The collimation member 20 makes it possible to make any beam (or sub-beam) reaching it parallel, which allows correct propagation of any beam at the output of the collimation member 20. The collimation member 20 is for example a lens, a parabolic mirror or a prism.

[0037] The device may also comprise a diffractive optical element 18 on the optical axis 16. The diffractive optical element 18 is upstream of the collimation member 20. The diffractive optical element 18 is placed before the collimation member 20. The diffractive optical element 18 is aligned with respect to the collimation member 20. The laser beam is able to reach the diffractive optical element 18 in a non-collimated state. The radiations of the non-collimated laser beam reaching the diffractive optical element 18 are non-parallel to each other. In other words, the laser beam is able to reach the diffractive optical element 18 in a convergent or divergent state. The diffractive optical element 18 is capable of dividing the non-collimated laser beam propagating along the optical axis 16 into a plurality of sub-beams.The sub-beams obtained at the output of the diffractive optical element 18 are non-collimated, that is to say convergent or divergent, in a similar manner to the non-collimated laser beam reaching the diffractive optical element 18. The collimating member 20 makes the sub-beams collimated, which allows better propagation of the sub-beams thereafter - and subsequently facilitates their focusing and machining. At the output of the diffractive optical element 18 (and upstream of the collimating member 20), the sub-beams are angularly spaced from one another, depending on the type of diffractive optical element 18 chosen. Then, the sub-beams are collimated by the collimating member 20. In other words, the radiation within each sub-beam is made parallel by the collimating member 20. In addition, downstream of the collimating member 20, the sub-beams are angularly spaced apart from each other.This allows the sub-beams to be angularly spaced or brought closer together, according to a variable (or adjustable) angle as described below. The variation of the angle between the sub-beams is carried out while keeping the sub-beams collimated. The diffractive optical element 18 also allows the number of sub-beams and the pattern of the sub-beams 241 to be defined, according to the desired machining.

[0038] The diffractive optical element 18 is movable relative to the collimation member 20. The diffractive optical element 18 can be moved along the optical axis 16, towards or away from the collimation member 20. The movement of the diffractive optical element 18 is linear. The movement of the diffractive optical element 18 is in translation. The translation takes place along the optical axis 16. The translation allows a movement of the diffractive optical element 18 towards or away from the collimation member 20. The diffractive optical element 18 is movable relative to the collimation member 20 while being illuminated by the non-collimated laser beam. The diffractive optical element 18 can occupy different positions, such as intermediate positions between extreme positions (approaching or moving away from the collimating member 20).The movement of the diffractive optical element 18 relative to the collimation member 20 is capable of varying the angle between the sub-beams, downstream of the collimation member. Downstream of the collimation member 20, the angular spacing between the sub-beams varies as a function of the diffractive optical element 18, the collimation member 20 and (the adjustment of) the position of the diffractive optical element 18 relative to the collimation member 20. For example, the further the diffractive optical element 18 is from the collimation member 20 (therefore the further the diffractive optical element 18 is upstream of the collimation member 20), the greater the angle between the sub-beams, downstream of the collimation member, and vice versa.In addition, the displacement of the diffractive optical element 18 relative to the collimation member 20 makes it possible to vary the angle between the sub-beams downstream of the collimation member 20, while preserving the shape and size of the sub-beams. The same applies to the conservation of the collimation of the sub-beams downstream of the collimation member 20. In other words, certain characteristics of the sub-beams are preserved even when the diffractive optical element 18 is displaced relative to the collimation member along the non-collimated laser beam. These characteristics remain identical even when the diffractive optical element 18 is displaced relative to the collimation member along the non-collimated laser beam. Regardless of the position of the diffractive optical element 18 and therefore the angle between the sub-beams, the sub-beams retain their shape and / or their size and / or their collimation.Thus, the sub-beams (projected onto a spherical surface whose center is on the optical axis 16 and at the origin of the sub-beams) have an identical shape and size but are more or less spaced apart from each other depending on the distance or approach of the diffractive optical element 18 relative to the collimating member 20. This makes it possible to carry out micro-machining of one or more parts in different values ​​of spacing of the sub-beams with a single optical device 10, while maintaining the same machining conditions. In this sense, the adjustment of the device (in particular the movement of the optical element 18, variation of the angle 26) can be carried out dynamically during machining. Thus, with a single optical device 10 the same machining conditions are maintained in a simple manner during machining - which simplifies the adjustment of the device and therefore the adjustment of the sub-beams.Because the shape and size of the sub-beams are preserved, micromachining is precise and consistent - regardless of the angular spacing of the sub-beams. In addition, this allows for rapid - but precise - adjustment of the device 10 and the system 50.

[0039] The shape of the sub-beams that is preserved corresponds to the spatial distribution of the energy within the sub-beams. It can be any geometric shape in a plane perpendicular to the optical axis 16 (corresponding to one or more parts 12, and more precisely, corresponding to the surface of one or more parts 12), such as circular, triangular, etc. It can also be any shape of the evolution of the transverse amplitude profile, such as a Gaussian shape, “top hat”, etc. The size of the sub-beams that is preserved corresponds to the dimensions (or amplitude) of the shape measured transversely to the optical axis 16.Furthermore, the movement of the diffractive optical element relative to the collimating member is capable of varying the angle between the sub-beams while allowing at least one of the characteristics among the polarization, the wavelength and the duration of the pulses of the sub-beams to be preserved and while allowing at least one of the characteristics among the polarization, the wavelength and the duration of the pulses of the laser beam upstream of the device in the sub-beams to be preserved. This makes it possible to simplify the adjustment of the device while increasing the repetition or variation of the machining operations.

[0040] The movement of the diffractive optical element 18 is preferably continuous, so that the diffractive optical element 18 occupies an infinite number of positions relative to the collimation member 20. The position of the diffractive optical element 18 is chosen according to the desired machining of the part(s) 12. The device 10 may be such that the movement of the diffractive optical element 18 is motorized. This makes it possible to precisely move the diffractive optical element 18 relative to the collimation member 20, so as to precisely achieve an angular spacing of the sub-beams, downstream of the collimation member 20. The motorization may be activated manually or with a control interface to further increase the precision and speed of the movement and positioning of the diffractive optical element 18.

[0041] The diffractive optical element 18 may be an active diffractive optical element. Preferably, the diffractive optical element 18 may be a passive diffractive optical element, which makes the device easier to adjust and less expensive.

[0042] The device 10 may further comprise one or more non-collimation members 22. The non-collimation member(s) 22 are on the optical axis 16, upstream of the diffractive optical element 18. Independently of the collimated or non-collimated state of the laser beam emitted by the laser 14, the non-collimation member(s) 22 allow shaping of the laser beam to be processed by the various elements and members further downstream. The non-collimation member(s) 22 are arranged in such a way that the sub-beams 241 downstream of the collimation member can have a size smaller than, equal to or larger than the size of the laser beam upstream of the device 10. Furthermore, the non-collimation member(s) 22 make it possible to put the laser beam in a non-collimated state, so that the laser beam arrives in a non-collimated state at the diffractive optical element 18.Thus, if the laser beam emitted by the laser 14 is collimated, the non-collimation member(s) 22 make it possible to make the laser beam non-collimated when the laser beam reaches the diffractive optical element 18. The non-collimation member(s) 22 are for example a lens, a parabolic mirror, a prism, etc. or a combination of these elements. Once the non-collimation member(s) 22 have been chosen and positioned in the device 10, the angle between the sub-beams, downstream of the collimation member 20, can vary by moving the diffractive optical element 18 - while retaining the shape and size of the sub-beams.

[0043] Figure 2 is a schematic view of the device 10 according to one embodiment. Figure 2 shows the device 10 in one operating state and Figure 3 is a schematic view of the device according to Figure 2, in another operating state. The device 10 comprises the diffractive optical element 18 upstream of the collimating member 20, the diffractive optical element 18 being movable relative to the collimating member 20. Furthermore, a non-collimating member 221 among the one or more non-collimating members 22 is placed upstream of the diffractive optical element 18. A laser beam 24, in a collimated state, reaches the non-collimating member 221, along the optical axis 16. The non-collimating member 221 changes the state of the laser beam 24 to make it non-collimated.The diffractive optical element 18 being between the non-collimation member 221 and the collimation member 20, the laser beam 24 arrives in a non-collimated state at the diffractive optical element 18, along the optical axis 16. More precisely, in the example of FIGS. 2 and 3, the laser beam 24 is in a convergent non-collimated state. The non-collimation member 221 is convergent.

[0044] According to Figure 2, the diffractive optical element 18 is positioned near the collimating member 20. The diffractive optical element 18 is capable of dividing the non-collimated laser beam 24 into a plurality of sub-beams 241 (two sub-beams are shown as an example). Upstream of the collimating member 20, the sub-beams 241 are angularly spaced according to the type of diffractive optical element 18. Each of the sub-beams 241 is then convergent. Then, downstream of the collimating member 20, the sub-beams 241 have an angle 26 between them which is variable. The sub-beams 241 have an angular spacing according to the angle 26 defined by the diffractive optical element 18, the collimation member 20 and the position of the diffractive optical element 18 relative to the collimation member 20.In projection onto the above-mentioned spherical surface, the sub-beams 241 have a silhouette 28 of a certain shape (round, in the example of FIG. 2) and a certain size. The angle 26 is between the most extreme sub-beams of the plurality of sub-beams, downstream of the collimating member 20.

[0045] Figure 3 shows another operating state of the device 10. The diffractive optical element 18 is moved relative to the collimation member 20 and positioned near the non-collimation member 221. Upstream of the collimation member 20, the sub-beams 241 are angularly spaced according to the type of diffractive optical element 18. Each of the sub-beams 241 is then convergent. Then, downstream of the collimation member 20, the sub-beams 241 obtained by splitting the laser beam 24 have another angle 26 between them, which has varied. The sub-beams 241 have a new angular spacing according to another angle 26 defined by the diffractive optical element 18, the collimation member 20 and the new position of the diffractive optical element 18 relative to the collimation member 20.In projection onto the spherical surface mentioned above, the sub-beams 241 have the same silhouette 28 with the same shape and the same size as the sub-beams 241 of FIG. 2. The displacement of the diffractive optical element 18 makes it possible to adjust the angular spacing between the sub-beams 241 - and therefore the spacing of the impact points of the sub-beams 241 in a plane perpendicular to the optical axis 16 which are the part(s) 12 - while retaining the characteristics which are the shape and size of the sub-beams. The device 10 allows such adjustment in a simple and rapid manner - before or during machining.

[0046] According to Figures 2 and 3, the non-collimation member 221 is capable of making the laser beam convergent, such that the collimated sub-beams 241 downstream of the collimation member 20 have a size smaller than the size of the laser beam 24 upstream of the device 10. It is also possible for the non-collimation member to be capable of making the laser beam divergent, such that the sub-beams 241 downstream of the collimation member 20 have a size greater than the size of the laser beam 24 upstream of the device 10. Thus, by choosing the non-collimation member from among the collimation members 22, it is possible to adjust the size of the sub-beams 241 according to the desired machining. Such an adjustment is simple and rapid.

[0047] Figure 4 is a schematic view of the device 10 according to another embodiment. Figure 4 shows the device 10 in an operating state and Figure 5 is a schematic view of the device according to Figure 4, in another operating state. The device 10 comprises the diffractive optical element 18 upstream of the collimating member 20, and movable relative to the collimating member 20. Furthermore, non-collimating members 222, 223 among the one or more non-collimating members 22 are placed upstream of the diffractive optical element 18. The laser beam 24, in a collimated state, reaches a first non-collimating member 222, along the optical axis 16. The first non-collimating member

[0048] 222 changes the state of the laser beam 24 to make it non-collimated. The laser beam 24 becomes divergent. Then the non-collimated laser beam 24 reaches a second non-collimation member 223, further downstream of the first non-collimation member 222, along the optical axis 16. The second non-collimation member

[0049] 223 changes the non-collimation state of the laser beam 24. The laser beam 24 is non-collimated but becomes convergent. The diffractive optical element 18 being between the second non-collimation member 223 and the collimation member 20, the laser beam 24 arrives in a non-collimated state at the diffractive optical element 18, along the optical axis 16. More precisely, in the example of FIGS. 4 and 5, the laser beam 24 is in a convergent non-collimated state.

[0050] According to Figure 4, the diffractive optical element 18 is positioned near the collimating member 20. The diffractive optical element 18 is capable of dividing the non-collimated laser beam 24 into a plurality of sub-beams 241 (two sub-beams are shown as an example). Upstream of the collimating member 20, the sub-beams 241 are angularly spaced according to the type of diffractive optical element 18. Each of the sub-beams 241 is then convergent. Then, downstream of the collimating member 20, the sub-beams 241 have an angle 26 between them, which is variable. The sub-beams 241 have an angular spacing according to the angle 26 defined by the diffractive optical element 18, the collimation member 20 and by the position of the diffractive optical element 18 relative to the collimation member 20.In projection onto the above-mentioned spherical surface, the sub-beams 241 have a silhouette 28 of a certain shape (round, in the example of FIG. 4) and a certain size. The angle 26 is between the most extreme sub-beams of the plurality of sub-beams, downstream of the collimating member 20.

[0051] Figure 5 shows another operating state of the device 10. The diffractive optical element 18 is moved relative to the collimating member 20 and positioned near the second non-collimating member 223. Upstream of the collimating member 20, the sub-beams 241 are angularly spaced according to the type of diffractive optical element 18. Each of the sub-beams 241 is then convergent. Then, downstream of the collimating member 20, the sub-beams 241 obtained by splitting the laser beam 24 have another angle 26 between them, which has varied. The sub-beams 241 have a new angular spacing according to another angle 26 defined by the diffractive optical element 18, the collimation member 20 and the new position of the diffractive optical element 18 relative to the collimation member 20 when they are downstream of the collimation member 20.In projection onto the spherical surface mentioned above, the sub-beams 241 have the same silhouette 28 with the same shape and the same size as the sub-beams 241 of FIG. 4. The displacement of the diffractive optical element 18 makes it possible to adjust the angular spacing between the sub-beams 241 - and therefore the spacing of the points of impact of the sub-beams 241 in a plane perpendicular to the optical axis 16 which are the part(s) 12 - while retaining the characteristics which are the shape and size of the sub-beams. The device 10 allows such adjustment in a simple and rapid manner.

[0052] According to Figures 4 and 5, the first non-collimation member 222 is capable of making the laser beam divergent and the second non-collimation member 223 is capable of making the laser beam convergent, such that the sub-beams 241 downstream of the collimation member have a size equal to the size of the laser beam 24 upstream of the device. Thus, by choosing the non-collimation members from among the collimation members 22, it is possible to adjust the size of the sub-beams 241 according to the desired machining. Such an adjustment is simple and rapid.

[0053] Figure 6 shows a schematic view of the device 10 according to one embodiment. The embodiment of Figures 2 and 3 is repeated here (as an example, that of Figures 4 and 5 could also be), with a schematic representation of three sub-beams 241 (as an example again). The middle sub-beam 241 is along the optical axis 16. The device 10 may further comprise a module 30 for shaping the sub-beams 241, downstream of the collimation member 20. The module 30 is an assembly of optical elements which are capable of modifying the characteristics of the sub-beams (such as the geometric, propagation or other characteristics). The module 30 makes it possible to process the sub-beams 241 with a view to machining the part(s) 12. In particular, the module 30 allows the device 10 to adapt to the micro-machining system 50 in which the device 10 can be integrated.In particular, the module 30 makes it possible to adapt the sub-beams 241 downstream of the device to the system 50 - for example to adapt the dimension of the outer envelope of the sub-beams 241 to the system 50.

[0054] Among the optical elements of the assembly forming the module 30, the device 10 may comprise, downstream of the collimating member 20, two optical elements 32, 34 converging on the optical axis 16. The optical elements 32, 34 may be separated by the sum of the focal distances of the optical elements 32, 34. The optical elements 32, 34 are a unit for inverting the angle of the sub-beams in the sense that the angle of each sub-beam, downstream of the collimating member 20, is inverted by the device. Thus, sub-beams moving away from each other before the optical element 32 move closer to each other after the optical element 34. This makes it possible to reduce the envelope of the sub-beams 241. According to Figure 6, the first optical element 32 is downstream of the collimation member 20 and the second optical element 34 is downstream of the first optical element 32.

[0055] Among the optical elements of the assembly forming the module 30, the device 10 may comprise, downstream of the optical elements 32, 34, a convergent optical element 36 and a divergent optical element 38. The convergent optical element 36 and the divergent optical element 38 are a unit for enlarging the sub-beams 241 to enlarge the size of the sub-beams 241, for example to obtain sub-beams 241 downstream of the optical element 38 of a size similar to or greater than the size of the laser beam 24 upstream of the optical element 22. The size of the sub-beams at the output of the device 10 may thus be adjusted to optimize the micro-machining of the part(s) 12.

[0056] The system 50 for micromachining the part(s) 12 comprising the device 10 is also proposed. The system 50 comprises the laser 14, for example of the continuous or pulsed type, preferably with short or ultra-short pulses. The emitted laser beam 24 may be in the ultraviolet, visible or infrared wavelengths. The laser beam 24 emitted by the laser 14 is along the optical axis. The micromachining allows the treatment of the part(s) 12. This may involve, for example, texturing the part 12 (or texturing a surface of the part), creating a cavity in the part 12 (cavity in a surface of the part which may not open onto another surface of the part), cutting the part 12 or drilling the part 12 (drilling from one surface of the part to another). The system allows numerous parts 12 to be reproduced identically.Micromachining concerns the processing of the part 12, the material removal of which during machining is done in a manner less than a millimeter, that is to say in a micrometric manner or less. The system 50 allows the micromachining of one or more parts in a simpler manner, the adjustment of the device 10 being reduced to the positioning of the diffractive optical element 18.

[0057] The system 50 may further comprise, downstream of the device 10, a scanner head 40. The scanner head 40 makes it possible to move the sub-beams 241 to carry out the machining of the part(s) 12. The part(s) 12 may be stationary or mobile. The scanner head 40 may comprise one or more motor-activated optical deflection elements—for example, of the galvanometric type. The system 50 may further comprise, downstream of the collimation member 20 and the scanner head 40, a focusing element 42. The focusing element 42 ultimately makes it possible to focus the sub-beams on the part(s) to be machined. Furthermore, the focusing element 42 makes it possible to ensure that an angular deviation of the sub-beams results in a linear displacement in said plane perpendicular to the optical axis 16 of the part 12.The focusing element 42 is for example an F-Theta lens making it possible to provide a focused point over the entire scanning field of the scanner head 40.

[0058] In Figure 1, the part 12 to be machined is shown as an example in alignment with the laser 14, along the rectilinear optical axis 16. However, the optical axis 16 may undergo deviations and the part(s) 12 may not be in alignment with the laser 14.

[0059] A method for micromachining one or more parts 12 is also proposed. The method comprises providing the micromachining system 50 and one or more parts to be machined. The part or parts 12 are downstream of the system 50 - in alignment with the laser 14 or not. The system 50 is adjusted to adjust the spacing of the sub-beams 241 on the part or parts 12. For this, the angle 26 between the sub-beams, downstream of the collimating member 20, is varied by moving the diffractive optical element towards or away from the collimating member 20. The movement of the diffractive optical element 18 is in translation along the optical axis 16. The angle 26 between the sub-beams can vary and then be fixed for machining. The angle between the sub-beams can also vary during machining.In other words, the angle - or angular spacing - between the sub-beams, downstream of the collimating member 20, is modified by adjusting the position of the diffractive optical element 18. During a machining operation, the angle 26 can vary as much as necessary. The device 10 is capable of ensuring a displacement of the diffractive optical element 18 and of varying the angle 26 during machining. The device 10 is capable of ensuring a dynamic displacement of the diffractive optical element 18. The device 10 is capable of ensuring a dynamic variation of the angle 26. The variation of the angle 26 takes place dynamically during machining. The displacement (in translation, linear) of the diffractive optical element 18 is dynamic during machining (unlike devices of the prior art where such a displacement cannot take place, dynamically, during machining).The sub-beams retain their shape and / or size and / or collimation regardless of the angle between the sub-beams as well as their spacing on the workpiece(s) to be machined induced by the angular spacing. The method further comprises machining the workpiece(s) 12 with the sub-beams. The positional adjustment of the diffractive element 18 makes it possible to quickly and simply adjust the spacing of the sub-beams 241 on the workpiece(s) - even during machining. The method makes it possible to simply machine one or more workpieces 12 (simultaneously). The adjustment of the system 50 in the machining process is rapid.

[0060] The method may also include other adjustments. The position adjustment of the diffractive optical element 18 may be achieved by motorizing the movement of the diffractive optical element 18. An interface also makes it possible to program the movement of the diffractive optical element 18. The method may include adjustments through the choice of the elements and members of the system 50 - in particular, within the device 10. The scanner head 40 and the focusing element 42 may be adapted to the machining to be carried out. With regard to the device 10, the collimation member 20 and the non-collimation members 22, if applicable, may be chosen according to the machining to be carried out. It is possible to enlarge, reduce or maintain the size of the laser beam 24 emitted by the laser 14. The optical elements of the module 30, if applicable, may also be chosen according to the machining to be carried out.

[0061] The present invention has been described in relation to specific embodiments, which are of purely illustrative value and should not be considered as limiting. In general, it will be obvious to a person skilled in the art that the present invention is not limited to the examples illustrated and / or described above.

Claims

Claims 1. Optical device (10) for a laser micromachining system, the device comprising • An optical axis (16), • A collimation member (20) on the optical axis (16), • A diffractive optical element (18) on the optical axis upstream of the collimation member (20), the diffractive optical element being capable of dividing a non-collimated laser beam propagating along the optical axis into a plurality of sub-beams (241) and being movable relative to the collimation member (20), the movement towards or away from the diffractive optical element (18) relative to the collimation member being capable of varying the angle (26) between the sub-beams (241) downstream of the collimation member (20), while retaining the shape and size of the sub-beams (241).

2. Device (10) according to claim 1, wherein the movement of the diffractive optical element (18) is linear and is motorized.

3. Device (10) according to one of the preceding claims, in which the diffractive optical element (18) is a passive element.

4. Device (10) according to one of the preceding claims, further comprising one or more non-collimation members (22) putting the laser beam propagating towards the diffractive optical element (18) in a non-collimated state, the non-collimation members being on the optical axis upstream of the diffractive optical element (18) and being arranged in such a way that the sub-beams (241) downstream of the collimation member have a size less than, equal to or greater than the size of the laser beam upstream of the device (10).

5. Device (10) according to claim 4, in which one (221) of the non-collimation members is capable of making the laser beam converge, such that the sub-beams (241) downstream of the collimation member (20) have a size smaller than the size of the beam upstream of the device.

6. Device (10) according to claim 4, in which one of the non-collimation members is capable of making the laser beam diverge, such that the sub-beams (241) downstream of the collimation member (20) have a size greater than the size of the beam upstream of the device.

7. Device (10) according to claim 4, wherein • a first non-collimation member (222) among the non-collimation members is capable of making the laser beam diverge, • a second non-collimation member (223) among the non-collimation members is capable of making the laser beam converge, such that the sub-beams (241) downstream of the collimation member have a size equal to the size of the beam upstream of the device.

8. Device (10) according to one of the preceding claims, in which the movement of the diffractive optical element (18) relative to the collimation member (20) is capable of varying the angle between the sub-beams (241) while allowing conservation of at least one of the characteristics among the polarization, the wavelength and the duration of the pulses of the sub-beams (241) and while allowing conservation of at least one of the characteristics among the polarization, the wavelength and the duration of the pulses of a laser beam upstream of the device in the sub-beams (241).

9. Device (10) according to one of the preceding claims, further comprising, downstream of the collimation member (20), an assembly of elements optics (32, 34, 36, 38) capable of modifying the characteristics of the sub-beams.

10. Device (10) according to one of the preceding claims, in which the movement towards or away from the diffractive optical element (18) relative to the collimation member is capable of varying the angle (26) between the sub-beams (241) downstream of the collimation member (20), while maintaining the collimation of the sub-beams (241).

11. System (50) for micromachining one or more parts (12), comprising: • A device (10) according to one of the preceding claims • A laser (14) capable of emitting a laser beam (24) along the optical axis (16).

12. System (50) according to the preceding claim, further comprising, downstream of the device (10) a scanner head (40) and a focusing element (42).

13. Method of micromachining one or more parts, comprising the steps of • Provision of a system (50) according to one of claims 11 or 12, • Supply of one or more parts (12) to be machined, the part(s) being downstream of the system, • Variation of the angle between the sub-beams (241) by moving the diffractive optical element (18) towards or away from the collimation member (20), the sub-beams (241) retaining their shape and size regardless of the angle between the sub-beams and their spacing on the part(s) to be machined, • Machining of the part(s) with the sub-beams (241).

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