DE102011051198A1 - Method for manufacturing weight-optimized deflection mirror for galvanometer scanner, involves removing substrate material from side of mirror support substrate by using laser light under formation of reinforcement structure in substrate - Google Patents

Abstract

The method involves manufacturing a mirror support substrate (2) from a substrate material by forming an erosion material channel in a workpiece, by generating laser light (9) with wavelength for which workpiece material is transparent and by forming a cavity in an inner side of the workpiece. The substrate material is removed from a rear side (5) of the substrate by using the laser light under formation of a reinforcement structure in the substrate. A mirror surface (7) is formed on a front side (3) of the substrate before the formation of the reinforcement structure. An independent claim is also included for a method for manufacturing a mirror support substrate from a substrate material.

Description

The invention relates to a method for producing a weight-optimized deflection mirror, z. B. a light weight deflection mirror for a galvanometer scanner, and method for producing a mirror carrier substrate z. For use in the manufacture of a weight optimized deflection mirror.

The provision of weight-optimized (i.e., weight-reduced) components is of considerable importance in many areas. For example, in various optical devices, such as in galvanometer scanners, in telescope construction and aerospace, weight-optimized mirrors are desired, which should have precisely worked, well-defined mirror surfaces and should have a high dimensional stability under the respective conditions of use.

So z. B. in many areas, such as in material processing, movable deflecting mirrors for spatial guidance of working laser beams eigesetzt. For example, such a deflection mirror may be attached to a rotatably mounted shaft of a galvanometer scanner, whereby the shaft and thus also the deflection mirror can be rotated by a galvanometer drive of the galvanometer scanner, so that a working laser beam is reflected by the reflection mirror on the deflection mirror and changing its rotational angular position a desired spatial position can be performed.

To z. For example, to enable a fast repositioning of such a deflection mirror to a different rotational angle position and not unnecessarily increase the requirements for a rotary drive (eg a galvanometer drive) of the deflection mirror, the weight and thus also the mass moment of inertia of the deflection mirror should be kept as low as possible. On the other hand, the deflection should have a good dimensional stability or rigidity so that it z. B. is deformed as little as possible even at high rotational speeds and at rapidly successive changes of direction.

The invention provides a method for producing a weight-optimized, dimensionally stable deflection mirror with a precisely shaped mirror surface and methods for producing a weight-optimized mirror support substrate.

According to a first aspect of the invention, a method for producing a weight-optimized deflection mirror, for. A deflection mirror for a galvanometer scanner, comprising providing a mirror support substrate of a substrate material and ablating substrate material on a side of the mirror support substrate to form a stiffening structure in the mirror support substrate, wherein the ablation of the substrate material is by means of laser light.

The substrate material is on the said side of the mirror support substrate z. B. from the outside (from the outside of the substrate material ago) removed inside. The substrate material can also be reversed from the inside to the outside of said side of the substrate material down what z. B. the substrate material for the laser light is transparent and a material removal takes place by focusing the laser light on certain positions and / or areas of the substrate material. When removing from inside to outside z. B. material initially on the remaining substrate material as long as adhering or adhering remain until the material removal reaches the outside of the substrate material, whereby an opening on the outside of the substrate material is formed, through which the previously inside ablated material to the outside and thus away from the remaining, the stiffening structure forming substrate material can pass. It can, for. Example, when using transparent to the substrate material substrate material also be so proceeding that is removed from the outside inwardly towards, wherein cavities with one or more over an outer opening or against outer openings present undercuts in the substrate material can be formed.

By the mirror carrier substrate is processed by means of laser light, the stiffening structure can be formed without contact and without mechanical force in or on the mirror support substrate, whereby z. For example, it is possible to prevent deformation of a side (for example a front side) provided for a mirror surface of the mirror support substrate. Thus, for example, the need for post-processing such a side after forming the stiffening structure may be eliminated. Furthermore, the stiffening structure z. B. with any three-dimensional shape, such as a tree structure with a central rib branching transverse ribs or as a honeycomb structure may be formed, such as by the laser light focused on a focus position on the provided for the stiffening structure side (eg, a back side) of the mirror support substrate is moved and the focus position under removal of substrate material according to the desired shape of the stiffening structure three-dimensional.

The mirror support substrate may, for. B. be a substantially disc-shaped substrate, wherein z. B. the front of the substrate may be provided for a mirror surface, and wherein z. B. the back of the substrate may be provided for the stiffening structure. The substrate material may, for. Example, for the wavelength of the laser light used substantially impermeable material or for the wavelength of the laser light (at lower intensities) is substantially transparent material, in the latter case, the material removal z. B. at intensities of the laser light above a material-specific material removal threshold by means of non-linear absorption mechanisms, eg. B. multi-photon absorption, can take place. The substrate material may, for. As glass, silicon, silicon carbide, and / or boron carbide or be, but the substrate may also have any other materials.

The term "removal of substrate material by means of laser light" here includes z. B. any kind of material removal by energy input by laser light, such as material removal by laser ablation, z. By cold ablation (ie, by substantially instantaneous evaporation of the material to be ablated without significant heat transfer to the remaining carrier substrate, with a fine, athermal removal of material) by ultrashort pulse lasers (eg, having pulse lengths in the picosecond range, e.g. ps), but also material removal by any kind of melting or evaporation of the substrate material (and removal of the melted or vaporized material, for example by blowing out with a dedicated process gas). The progress of the material removal can, for. B. in real time, such as by depth measurement using a designated -. B. optical - measuring device to be monitored.

When using a substrate made of a material substantially impermeable to the laser light, the removal of the substrate material z. B. in layers (as explained above, for example, from outside to inside), z. B. by first cross-sectional areas of the ablated material volume (or sub-areas thereof) are scanned laterally with material removal with a focus of the laser light and then the depth position of the laser focus is traced according to the ablated layer thickness.

The contactless removal of material by means of laser light is suitable for. B. also for very hard substrate materials, which are machinable by mechanical methods only with increased effort (eg., Material, tools, force and time use). Furthermore, by such a contactless material removal z. For example, stiffening structures with an arbitrary three-dimensional shape and with (for example, with respect to pattern widths which can be achieved by means of mechanical contact methods) small feature widths and radii of curvature are made possible.

According to one embodiment, the method further comprises forming a mirror surface on a side of the mirror support substrate other than the side intended for the stiffening structure, e.g. B. on a side opposite to the intended for the stiffening structure side.

The material removal takes place z. B. such that is not (in any case) or for the most part not completely removed through the substrate material, so that no or mostly no through hole is formed, but always or mostly on that side of the substrate material, which is opposite to the intended for the stiffening structure side is maintained, a substrate material bottom is maintained, whereby an uninterrupted or substantially continuous surface can be provided on this page, which z. B. can be used to provide or for forming a mirror surface. On the side of the stiffening structure such substrate material can be preserved such that there z. B. such a large continuous surface remains that on this surface z. B. a mirror surface can be provided or formed for a measuring light beam.

The formation of a mirror surface on the side facing away from the stiffening structure of the substrate material and / or on the side of the stiffening structure may, for. By polishing a corresponding side surface of the mirror support substrate (eg, when the substrate material is a metal and the deflection mirror is provided as a metal mirror) or by forming (eg, stacking, such as vapor deposition) a dielectric mirror on a corresponding side surface ,

According to one embodiment, the formation of the mirror surface facing away from the stiffening structure takes place before the formation of the stiffening structure.

According to this embodiment, z. B. a load occurring during the formation of the mirror surface (for example, mechanical pressure during polishing or when applying a dielectric mirror, caused for example by different thermal expansion coefficients, voltages) are well intercepted by the not yet weight-reduced (and thus more stable) substrate, wherein the risk of deformation of the mirror surface can be kept low. Since the subsequent formation of the stiffening structure by means of laser light can be done without mechanical force, also the risk of deformation of the now (by the removal of material in forming the stiffening structure) weight-reduced and thus by mechanical force easier deformable substrate also be kept low.

However, the formation of the mirror surface can also take place after the formation of the stiffening structure.

According to a further embodiment, the removal of the substrate material takes place under the formation of such recesses defining the stiffening structure, the recess bottom of which is arc-shaped and / or dome-shaped. However, the recesses may also be provided with any shape, for. As an analytical function, resulting from numerical optimizations or leaning on examples from biology (such as leaf ribs) lean.

According to this embodiment, owing to the arcuate structures of the stiffening structure, which are curved at least in a cross section of the carrier substrate, a high stability or dimensional stability of the deflecting mirror can be made possible with a simultaneously low weight.

According to a further embodiment, the laser light has a wavelength for which the substrate material is transparent, and the removal of the substrate material by means of focusing the laser light on a focus position and moving an envelope surface of a volume of the substrate material to be removed with the focus position to the volume along the envelope surface of to dissolve the surrounding substrate material.

According to this embodiment, the substrate z. Example, be made of a material which is (at low light intensities) substantially transparent to the laser light used, and the laser light can be focused so that a corresponding Materialabtrag- or material conversion threshold of the light intensity is reached only at the focus position. Furthermore, according to this embodiment, the removal of the substrate material block by block by z. B. only the envelope surface of a block or volume to be removed (or lying in the substrate interior surface of such an envelope surface) is traversed, wherein the volume along this surface, z. B. by material removal or material conversion (eg., Pulverization), is released from the surrounding substrate material and this volume is quasi cut out of the substrate.

According to a second aspect of the invention, a method for producing a weight-optimized mirror support substrate, such. A mirror carrier substrate of a deflection mirror for a galvanometer scanner, made of a workpiece of a workpiece material, comprising forming a removal material discharge channel in the workpiece which is open to an outside of the workpiece; the generation of laser light, which z. B. is generated with a wavelength for which the workpiece material is transparent, and forming a cavity or recess in the interior of the workpiece by focusing the laser light on a focus position in the interior of the workpiece and method of the focus position in the interior of the workpiece to the respective Focusing position by the laser light to remove material of the workpiece, wherein the removed material is conveyed through the Abtragmaterial-Abführkanal out of the interior of the workpiece.

The removal material discharge channel can, for. B. by optical or mechanical drilling of the workpiece from the corresponding outside of the same forth.

The Abtragmaterial-discharge duct can be formed before or after the workpiece material is removed in the region of the cavity.

The workpiece material may, for. Example, be a material that is substantially transparent to the wavelength of the laser light used (at lower light intensities at which multi-photon absorption is negligible), wherein the material removal z. B. at intensities of the laser light above a material-specific material removal threshold by means of energy input via non-linear absorption mechanisms, eg. B. multi-photon absorption, can take place. A material removal inside the workpiece can, for. B. be done by the laser light, z. B. by appropriate choice of the light output and the focus size, is focused on a focus position in the interior of the workpiece such that the material removal threshold is reached only at the focus position.

The cavity is formed so as to be in communication with the ablation material discharge passage, so that the workpiece material ablated at the respective focus position of the laser light can be conveyed out of the workpiece through the discharge passage. For example, the material removed inside the workpiece may be conveyed out of the workpiece by gravity via the discharge channel. For example, it can be provided to cut out partial volumes from the workpiece material in the interior of the workpiece by traversing corresponding partial volume envelope surfaces with the laser focus, the dimensions of these partial volumes being selected such that the partial volumes can be conveyed out of the workpiece through the discharge channel. The cavity can also be cut out along its ultimately complete envelope surface and the corresponding out of the Workpiece material cut out workpiece material volume (which corresponds to the total cavity volume) are transported out of a suitably large Abtragmaterial-discharge channel in one piece out. As another example, the workpiece material may be vaporized at the focus position and the resulting gaseous material may escape through the discharge channel, e.g. B. are sucked by vacuum.

It can be provided that a plurality of removal material discharge channels lead into one and the same cavity, but it can also be provided that only a single discharge channel opens into an associated cavity. The cavity can z. B. be formed as a substantially closed cavity, wherein a transverse extension of a respective discharge channel, the z. B. is measured substantially perpendicular to a direction of the same, smaller - z. B. much smaller - can be as a parallel transverse extension of the associated cavity. The cavity may be formed with respect to the discharge channel with an undercut. For example, the transverse extent of the discharge channel may be less than 1/2, less than 1/4, less than 1/10, or even less than 1/20 of the transverse extent of the associated cavity. As another example, the orifice area defined by the area of the mouth of the ablation material discharge channel on the outside of the workpiece may be smaller (eg, substantially smaller) than the cavity envelope area forming the cavity. envelops. For example, the orifice area may be less than 1/10, less than 1/100, less than 1/500, or less than 1/1000 of the cavity envelope area.

By allowing one or more such cavities to be created inside the workpiece, they (or the workpiece material remaining between them) can define a support structure of the workpiece, e.g. B. define a support structure in the interior of the workpiece, the z. B. has a structure in the form of a web connected by webs upper belt and lower belt, wherein the weight-optimized component can have a high rigidity or dimensional stability at relatively low weight.

According to one embodiment, generating laser light comprises generating a plurality of spatially separated laser beams, wherein focusing the laser light comprises focusing the plurality of laser beams on a common focus position.

According to this embodiment, for. B. several laser beams are generated, which are each focused on the common focus position in the interior of the workpiece and intersect at this focus position. According to this embodiment, the light output of each of the laser beams z. B. are selected such that the material removal threshold can be achieved only by the summation of the individual light outputs at the common focus position. Accordingly, the required for material removal total light output z. B. be divided on the individual laser beams, whereby z. B. occurring in the entrance or exit area before or after the focus position of a respective laser beam energy input (in the workpiece material) can be reduced, whereby z. B. a concomitant, undesirable material stress can be kept low.

Furthermore, according to this embodiment, for. For example, the dimensions of a crossing or machining area, within which a threshold value of the light intensity required for machining the workpiece material, can be reduced and thus a higher machining accuracy (eg in the form of a lower surface roughness) can be achieved. For example, the focal range of a laser beam along the propagation direction of the beam is typically less well defined (i.e., more extended) than in a transverse direction (i.e., a direction transverse to the propagation direction). Thus, the two laser beams z. B. are performed such that the (maximum) dimensions of the crossing region of the beams substantially correspond to the transverse dimensions of the focus region of a respective one of the laser beams and thus the crossing region has smaller dimensions than the focus region of a single beam.

According to a further embodiment, the cavity is formed with a volume which is greater than the volume of the Abtragmaterial-Abführkanals.

For example, the cavity may be formed as an extension which adjoins the end of the discharge channel located inside the workpiece. For example, the cavity may be formed with a volume greater than twice, ten times, one hundred times or one thousand times the volume of the discharge channel. Accordingly, by means of a small discharge channel a comparatively large cavity and thus a corresponding reduction in weight can be made possible, wherein the muzzle surface of the discharge channel lying on the outer surface of the workpiece can be kept small. However, the cavity and the discharge channel can also be formed in any hollow volume shape according to a desired, remaining from the workpiece material stiffening structure, wherein z. B. the cavity and the discharge channel are formed together in a shape that those of the first aspect described recess / recesses corresponds.

As in the first aspect, the cavity or cavities and the associated discharge channel (s) are e.g. B. formed in such a way that (always) no or substantially no through-holes are formed, so that on a side different from that side of the workpiece on which the outer orifice of the discharge channels or is present (this side is, for example, that side of the Workpiece on which the discharge channels open, opposite) an uninterrupted or substantially uninterrupted surface is present.

According to another embodiment, the method further comprises forming a mirror surface on at least one side of the mirror support substrate, e.g. B. on that side, which is the side on which the discharge channels open, opposite, whereby also on this side, on which the discharge channels open, a mirror surface may be formed.

The mirror support substrate may, for. B. be a substantially disc-shaped substrate, wherein z. B. one or the front of the substrate may be provided for the mirror surface, and wherein z. B. one or more Abtragmaterial-Abführkanäle can open at the back of the substrate, wherein z. B. several or all of the discharge channels may be connected to a common cavity or z. B. each discharge channel with an associated, from the other cavities z. B. each separate cavity can be connected. It can, for. B. also be provided to form both the front and the back of the substrate with similar mirror surfaces (eg., By applying respective dielectric mirror layers), wherein z. B. any resulting from the formation of the mirror surfaces influences (eg., Mechanical stresses) can compensate each other and thus substantially prevents deformation or warping of the substrate or at least reduced. The formation of the mirror surface (s) can, for. Example, by polishing a respective side surface of the mirror support substrate or by forming a dielectric mirror on a respective side surface. However, the mirror support substrate may also be provided with any other shape, z. B. be provided prior to forming the mirror surface with a faceting.

According to one embodiment, the formation of the at least one mirror surface takes place before the formation of the cavity.

According to this embodiment, z. B. a occurring during the formation of the mirror surface (mechanical) load from the not yet weight-reduced substrate are well intercepted, the risk of deformation of the mirror surface can be kept low. Since the subsequent formation of the cavity or several such cavities by means of laser light can be done without mechanical force, also the risk of deformation of the now (by the removal of material during the formation of the cavity or the cavities) weight-reduced and thus more easily deformable by mechanical force substrate also be kept low.

For example, firstly, the at least one mirror surface may be formed on a front side of the substrate, and subsequently one or more cavities may be formed by focusing the laser light from a back side of the substrate to a focus position inside thereof, the abraded material being e.g. B. by one or more associated Abtragmaterial-discharge channels, which open at the back of the substrate, can be conveyed out of the substrate interior. It may also be provided to first form the at least one mirror surface on a front side of the substrate and subsequently to form one or more cavities by focusing the laser light from this front side of the substrate (and through the mirror surface) to corresponding focal positions in the interior of the substrate, wherein the wavelength of the laser light z. B. can be set so that the mirror surface is transparent to them (i.e., the mirror surface is not reflective at this wavelength).

However, the formation of the at least one mirror surface can also take place after the formation of the cavity (s).

According to an embodiment, forming the ablation material discharge channel by focusing the laser light on a focus position on the (provided for the mouth of the discharge channel) outside of the workpiece and method, with material removal by the focused laser light, the focus position takes place in the interior of the workpiece.

According to this embodiment, the Abtragmaterial-discharge channel z. B. without using additional tools, such as drills are formed, for. B. just before forming a subsequent to the discharge channel cavity by means of the laser light.

According to a third aspect, a method of manufacturing a weight optimized mirror support substrate, e.g. B. a mirror carrier substrate of a deflection mirror for z. B. a galvanometer scanner, provided from a workpiece of a workpiece material, comprising generating laser light having a wavelength, for. B. with such a wavelength for which the Workpiece material is (substantially) transparent, the focusing of the laser light to a focus position and the departure of a partial volume of the workpiece, for. B. a partial volume within the workpiece, wherein the partial volume z. B. adjacent to an outer surface of the workpiece, with the focus position to modify the workpiece material within the sub-volume such that the modified workpiece material (within the sub-volume) to an etchant has a higher etching rate than the unmodified workpiece material (outside of the sub-volume); and etching the workpiece with the etchant, wherein the modified workpiece material is etched out of the workpiece.

According to this aspect, a recess (or a plurality of corresponding recesses) having an arbitrary three-dimensional shape can be formed in the workpiece by selectively etching out the modified material. The access to the recess can be made by etching, z. B. if the modified or modifiable sub-volume has a connection to an outer surface of the workpiece. The access to the modified partial volume can also be mechanical (eg by means of drilling or milling) or by removal by laser light such. B. according to the first and / or according to the second aspect. For example, it may be provided to shape the sub-volume (or a plurality of corresponding sub-volumes) in such a way that the resulting recesses define a stiffening structure on an outer side (eg on a rear side) of the workpiece. It can also be provided to form the sub-volume (or a multiplicity of corresponding sub-volumes) in such a way that the resulting recesses are formed in the interior of the workpiece in the form of substantially closed cavities, the cavities (or the workpiece material remaining between them) z. B. can define a lying inside the workpiece support structure.

The third aspect described above may, for. B. also be applied in the method according to the first and the second aspect. That is, in the methods according to the first and second aspects, the material to be removed may be initially modified by laser light (while still remaining adhered to the residual workpiece material) and then separated from the remaining workpiece by means of the etchant (separation / Releasing the material connection between the material to be removed around the remaining workpiece material). The partial volume according to the third aspect may, for. B. correspond to the cavity of the second aspect. In the method according to the first and the second aspect, however, can also be provided, the material to be removed directly by means of the laser light from the workpiece, such. B. the mirror support substrate to separate or separate or detach.

The properties of the laser beam (eg the wavelength, the light power, the focus size and / or the pulse duration, if a pulsed laser is used) can, for. B. adjusted and tuned to the workpiece material, that a threshold value of the light intensity, which is required for corresponding modification (i.e., changing the properties) of the workpiece material, is reached only at the focus position.

The "modifying" of the workpiece material at the focus position here includes z. B. any kind of change in the properties of the workpiece material such that the modified workpiece material with respect to the etchant has a higher etching rate than the original, unmodified workpiece material. For example, it may be provided to adjust the properties of the laser light and / or the workpiece material such that the workpiece material is pulverized or assumes a porous structure at the focus position, wherein an increase in the etching rate of the thus modified workpiece material z. B. can be achieved by means of the thus enlarged attack surface. However, it can also be provided to select the properties of the laser light and / or of the workpiece material in such a way that the workpiece material at the focus position changes into another phase, which has a higher etch rate than the original phase compared to the etchant. The etchant may, for. Example, a liquid etchant (such as an acid) or a gaseous etchant.

The generation of laser light may also in this case (analogous to the method described with reference to the second aspect) comprise generating a plurality of spatially separated laser beams, wherein focusing the laser light comprises focusing the plurality of laser beams on a common focus position. In this case, the light output of each of the laser beams z. B. are selected such that the required for modifying the workpiece material threshold of the light intensity can be achieved only by the summation of the individual light outputs at the common focus position.

The workpiece may also be a mirror support substrate in this case (analogously to the method described with reference to the second aspect), wherein the method may further comprise forming a mirror surface on at least one side of the mirror support substrate.

The three aspects discussed above may be used in combination, e.g. B. Aspects two and three or one to three or one and two or one and three, be applied, wherein recesses on a workpiece, such. B. on a mirror support substrate, on which one and / or the other way can be formed.

The invention will be explained below with reference to embodiments with reference to the accompanying drawings, wherein the same or similar features may be provided with the same reference numerals. In the drawings show:

1A and 1B a schematic illustration of a method according to an embodiment of the invention for producing a weight-optimized deflection mirror

2 a schematic illustration for explaining a possible shape in which in the 1A and 1B illustrated method,

3A - 3C a schematic illustration of a method according to an embodiment of the invention for producing a weight-optimized component for use as Spiegelträgersubtrat,

4 1 is a schematic illustration for explaining a method according to another embodiment for producing a weight-optimized component for use as a mirror carrier substrate,

5A - 5C a schematic illustration of a method according to another embodiment for producing a weight-optimized deflection mirror, and

6A - 6D a schematic illustration of a method according to an embodiment of the invention for producing a weight-optimized component serving as a deflecting mirror.

The 1A and 1B illustrate a method according to an embodiment for producing a weight-optimized deflection mirror 1 , According to 1A In a first method step, a mirror carrier substrate is produced 2 made of a substrate material. According to the illustrated embodiment, the mirror support substrate is 2 a disc-shaped, plane-parallel carrier substrate 2 which with its front 3 in negative z-direction of the in the 1A and 1B pointing xyz coordinate system pointing and with its back 5 is provided pointing in the positive z-direction.

In a further method step, a mirror surface is formed 7 on the front side 3 of the mirror carrier substrate 2 educated. According to 1A be z. B. one or more dielectric layers (in the 1A and 1B not shown individually) to form a dielectric mirror or the mirror surface 7 on the front side 3 of the carrier substrate 2 applied, z. B. piled by means of a vapor deposition process.

In a further process step becomes laser light 9 , according to 1A z. B. a laser beam 9 , on a focus position 11 at the back 5 of the carrier substrate 2 focused. The properties of the laser light or laser beam 9 - z. As the wavelength, the light output, the focus size and / or the pulse duration (if a pulsed laser is used) - are adjusted and tuned to the substrate material that at the focus position 11 an ablation of the substrate material by means of the laser light 9 he follows. For example, the laser beam 9 an ultrashort pulse laser beam, e.g. With pulse picosecond (eg, 10 ps or smaller) pulse durations and the characteristics of the laser beam 9 may be adjusted so that the removal of the substrate material by means of cold ablation.

The laser beam 9 is to form a stiffening structure 13 in the carrier substrate 2 (By material removal at the respective focus position 11 of the laser beam 9 ) over the back 5 of the carrier substrate 2 guided. The method of focus position 11 of the laser beam 9 can z. B. by means of a (in 1A not shown), the laser scanning head z. B. can be set up so that from him the laser beam 9 in the xy plane of the xyz coordinate system can be guided laterally (indicated by the arrows in 1A ) and / or the focus position 11 can be moved vertically in the z-direction. However, it can also be provided, the stiffening structure 13 by moving the carrier substrate 2 in fixed focus position 11 of the laser beam 9 train.

In the method according to the 1A and 1B the formation of the mirror surface takes place 7 before forming the stiffening structure 13 , However, it can also be provided, the mirror surface 7 after forming the stiffening structure 13 train.

1B illustrates the deflection mirror 1 with the on the carrier substrate 2 finished stiffening structure 13 , In the method according to the 1A and 1B becomes the stiffening structure 13 in the form of a kind of tree structure with a main bridge 15 and thereof perpendicularly branching transverse webs 17 formed, wherein the webs 15 . 17 as an example have a rectangular cross-section and those between the webs 15 . 17 formed recesses z. B. cuboid.

2 illustrates the formation of a stiffening structure 19 according to another Embodiment in which the removal of the material of the mirror carrier substrate 2 by means of the laser beam 9 (in 2 not shown) with the formation of recesses 21 takes place, the recess bottom 23 each arcuately curved. According to this embodiment, the stiffening structure 19 thus of the arcuate recesses 21 defined and has a main bridge 25 with arcuately sloping flank walls, wherein the arcuate structures z. B. can additionally increase the dimensional stability of the produced deflection mirror.

It can also be provided that the removal of substrate material to form recesses with a respective dome-shaped curved recess bottom (ie, all-round arcuate recess bottom), whereby z. B. all webs of a stiffening structure defined by such recesses may have arcuately sloping flank walls. Furthermore, a material removal by means of laser light z. B. suitable stiffening structures with any, z. B. arbitrarily curved, three-dimensional shape even at a low number of pieces (of, for example, a piece) to produce economically, the shape design by the flexible three-dimensional guiding the focus position 11 of the laser beam 9 (For example, by means of appropriate programming of an associated Laserscankopfes) can be extremely flexible.

In the case of the 1A . 1B and 2 Illustrated method, the carrier substrate 2 z. B. from one for the laser light 9 be substantially intransparent material, the material removal z. B. can be done in layers, with z. B. initially parallel to the xy plane extending cross-sectional areas of the ablated volume with material removal with the focus position 11 are traversed and then the z-coordinate of the focus position 11 nachgefahren according to the removed layer thickness.

However, in the case of the 1A . 1B and 2 Illustrated method, the carrier substrate 2 z. B. also from one (at low light intensities) for the laser light 9 be substantially transparent material, wherein the material removal z. B. can be done in blocks. For example, only the lying in the substrate interior parts of the envelope surfaces of the ablated volumes (such as the arcuate recesses 21 ) with the focus position 11 be traveled, wherein the ablated volumes by means of the laser light 9 are released from the surrounding substrate material (eg, by material removal or material conversion, eg, pulverization, at the respective focus position 11 ), so that these volumes virtually from the carrier substrate 2 can be cut out. In this case, the properties of the laser beam 9 - z. As the wavelength, the light output, the focus size and / or the pulse duration - adjusted and tuned to the substrate material that a material removal or material conversion required threshold value of the light intensity only at the focus position 11 is reached.

The 3A to 3C illustrate a method according to an embodiment for producing a weight-optimized device serving as Spiegelträgersubtratenden 49 from a workpiece 31 , which consists of a workpiece material. According to the 3A and 3B In a first method step, a removal material discharge channel 33 formed from an outside base 35 of the workpiece 31 from substantially perpendicular to the same in the interior of the workpiece 31 extends, wherein the discharge channel 33 to the bottom 35 is open.

According to the 3A and 3B is first laser light by means of a (not shown) laser 37 , here z. B. a laser beam 37 , generated, the laser light 37 a wavelength for which the workpiece material is transparent at low light intensities at which no non-linear absorption mechanisms occur. In the execution according to the 3A to 3C the laser beam occurs 37 from a top 39 of the workpiece 31 into the workpiece 31 and is initially on a focus position 41 on the bottom 35 of the workpiece 31 focused.

The properties of the laser beam 37 - z. As the wavelength, the light output, the focus size and / or the pulse duration (if a pulsed laser is used) - are adjusted and tuned to the workpiece material that at the focus position 41 an ablation of the workpiece material by means of the laser light 37 he follows. For example, the light output and the focus size (ie, the cross section of the laser beam at the focus position 41 ) is set such that at the focus position 41 a material removal threshold of the light intensity required to ablate the workpiece material by energy input via non-linear absorption mechanisms (eg, two-photon absorption) is achieved. For example, the laser beam 37 an ultrashort pulse laser beam, e.g. B. with pulse widths in the size of picoseconds, and the properties of the laser beam 37 can be adjusted so that the removal of the workpiece material is done by cold ablation.

According to the in the 3A to 3C Illustrated method is the Abtragmaterial-discharge channel 33 formed by the focus or the focus position 41 of the laser beam 37 from the position at the bottom 35 of the workpiece 31 under material removal by the focused laser light 37 in the Interior of the workpiece 31 into it, here z. B. along the z-direction of in 3B illustrated coordinate system. The removed workpiece material 42 can z. B. by gravity from the interior of the workpiece 31 be transported out, as in 3B through the dashed arrow 43 indicated. The three-dimensional guiding or method of the focus position 41 of the laser beam 37 (in 3A indicated by the pointing to the left or right arrows) can z. B. analogous to the configuration described above by means of a corresponding (not shown) Laserscankopfs done.

In a further method step, as in 3C illustrates a cavity 45 inside the workpiece 31 formed, which directly to the inside of the workpiece 31 lying end of Abtragmaterial-Abführkanals 33 followed. According to the execution of the 3A to 3C becomes the cavity 45 formed by the focus position 41 of the laser beam 37 after completion of the ablation material discharge channel 33 according to the desired shape of the cavity 45 inside the workpiece 31 is moved three-dimensionally, wherein at the respective focus position 41 through the laser light 37 Material of the workpiece 31 is removed. The abraded material is passed (eg, by gravity) through the ablation material discharge channel 33 through out of the interior of the workpiece.

As in 3C illustrates, the cavity can 45 as an extension (or with respect to the discharge channel 33 present undercut) are formed, which directly to the lying inside the workpiece end of Abführkanals 33 connects, with one parallel to the bottom 35 of the workpiece 31 extending transverse extent D of the discharge channel 33 (eg a diameter D of the discharge channel 33 ) is smaller (eg substantially smaller) than a transverse extension L of the cavity running parallel thereto 45 , In other words, the discharge channel 33 and the cavity 45 be formed such that a substantially perpendicular to the direction of the Abführkanals 33 measured transverse extent D of the discharge channel 33 is smaller than a parallel extending transverse extent L of the cavity 45 , Furthermore, the discharge channel 33 and the cavity 45 be formed such that z. B. the mouth area 57 the discharge channel 33 on the bottom 35 of the workpiece 31 (substantially) smaller than the cavity 45 defining cavity envelope surface 59 ,

With the finished forming of the cavity 45 in the workpiece 31 is the production of the weight-optimized component 49 from the workpiece 31 completed. In the method according to the 3A to 3C becomes only a single cavity 45 in the workpiece 31 educated. However, it may be provided to form a plurality of such cavities in a workpiece by means of the method described above (see also FIG 4 ), where z. B. several Abtragmaterial discharge channels can open into a single of these cavities, or wherein z. B. each of these cavities may be connected to a separate discharge channel. The multiple cavities can z. B. define a arranged in the interior of the workpiece or component support structure, which gives the component at (compared to the workpiece) reduced weight high dimensional stability or stability.

4 illustrates a method according to another embodiment for producing a weight-optimized component serving as a mirror support substrate 49 , The embodiment of the method according to 4 differs from the embodiment according to the 3A to 3C in that according to the in 4 illustrated embodiment, here two, spatially separated from each other laser beams 51 . 53 are generated and each on a common focus position 55 inside the workpiece 31 be focused so that they are at the focus position 55 cross.

The properties of the two laser beams 51 . 53 - z. As the respective light output and focus size - are set such that the light intensity of only one of the two laser beams 51 . 53 at the focus position 55 is insufficient to achieve a material removal threshold required to ablate the workpiece material by energy input via non-linear absorption mechanisms (eg, two-photon absorption).

Furthermore, the properties of the two laser beams 51 . 53 set such that by summing up the light intensities of the individual laser beams 51 . 53 at the focus position 55 total light intensity achieved is equal to or greater than the material removal threshold. Thus, z. B. the light output required for material removal on several (here on two) laser beams 51 . 53 be distributed, wherein each of the plurality of laser beams may have a lower light output than in a material removal by means of only a single laser beam. Thus, z. B. the spatial extent of the area at the focus position 55 , in which the total light intensity is sufficient for a material removal, by means of the properties of the two laser beams 51 . 53 to be influenced. Furthermore, according to this embodiment of the method, owing to the lower light output of the individual laser beams, an energy input (for example an undesired heating) into the workpiece material in the entry region of a respective laser beam may occur 51 . 53 before reaching the focus position 55 and in the exit area of a respective laser beam 51 . 53 after passing through the focus position 55 be reduced or distributed over a larger area of space, whereby z. B. a potentially caused by such an energy input material load (eg., In the form of tensions caused by temperature differences) can be reduced.

4 further illustrates the formation of multiple cavities 45 in the workpiece 31 or in the component 49 , here z. B. each of the cavities 45 with an associated removal material discharge channel 33 connected is. The cavities 45 (or lying between them, remaining workpiece material) may, for. B. a support structure in the interior of the workpiece 31 or of the component 49 define, where the cavities 45 and thus also the support structure by corresponding three-dimensional method of the focus position 41 . 55 can be formed with any shape.

In the methods according to the 3A to 3C and 4 will each of the cavities 45 formed with a volume which is larger (here, for example, substantially larger) than the volume of the respective associated Abtragmaterial-Abführkanals 33 where z. B. the transverse extent (width) L of the respective cavity 45 (substantially) is greater than the transverse extent (width) D of the associated discharge channel 33 ,

Thus, the cavities 45 as essentially closed cavities 45 be formed, the outside of the workpiece 31 to which the associated discharge channels 33 can remain largely intact and still a (comparatively) high weight reduction can be made possible by the workpiece 31 as it were "eroded".

According to the in the 5A to 5C illustrated method according to one embodiment, the workpiece 31 z. B. a mirror carrier substrate 61 be. As in 5A illustrated, according to this embodiment, in a first process step z. B. a mirror surface 63 on a front side 65 of the carrier substrate 61 be trained here z. By forming a dielectric mirror 63 ,

As in 5B illustrated in a further process step analogous to the procedure described above z. B. several cavities 67 in the carrier substrate 61 trained, here z. B. by first several corresponding Abtragmaterial-Abführkanäle 69 on a backside 71 of the substrate 61 be formed and then a laser beam 73 from the back 71 of the mirror carrier substrate 61 fro to a respective focus position 75 inside the substrate 61 is focused to material at this position of the substrate 61 ablate. From the (not weight-optimized) mirror carrier substrate 61 thus becomes a weight-optimized mirror support substrate 77 produced.

As in 5C illustrated, in a further process step, a second mirror surface 79 at the now weight-optimized mirror support substrate 77 be formed. In the embodiment according to the 5A to 5C For example, one or more dielectric layers (in 5C not shown individually) to form a dielectric mirror 79 on the back side 71 of the weight optimized substrate 77 applied. The mouth openings of the Abtragmaterial-Abführkanäle 69 at the back 71 the weight-optimized carrier substrate 77 need z. B. not through the layers of the dielectric mirror 79 be covered.

The deflecting mirror 81 according to the embodiment of 5C can z. B. as a two-sided reflective deflecting mirror 81 be formed, wherein z. B. from the Abtragmaterial-Abführkanälen 69 opposite mirror surface 63 , which is easily formed continuously, can be provided for deflecting a working light beam, and wherein z. B. on the side of Abtragmaterial-Abführkanäle 69 present mirror surface 79 which are usually from these ablation material discharge channels 69 (Or their Ausmündungsöffnungen on the associated mirror surface 79 ) is interrupted, may be provided for guiding a measuring light beam, the z. B. for determining the rotational angular position of the deflection mirror 77 can serve. The Abtragmaterial-Abführkanäle 69 (Or their Ausmündungsöffnungen) can z. B. are arranged in accordance with the impingement of the measuring light beam and / or dimensioned so that they can not be hit by the measuring light beam during operation. The Abtragmaterial-Abführkanäle 69 (Or the Ausmündungsöffnungen) may be formed so small in diameter that only occur negligible losses or non-interfering stray light when exceeded by the measuring light beam.

According to the in the 5A to 5C illustrated embodiment, the mirror surface 63 on the front side 65 of the substrate 61 before forming the cavities 67 educated. However, it may be provided both the mirror surface 63 on the front side 65 as well as the mirror surface 79 on the back side 71 (eg, simultaneously) after forming the cavities 67 to build.

The 6A to 6D illustrate a method for producing a weight-optimized component 91 , in this case a weight-optimized deflection mirror 91 with a weight optimized mirror support substrate 95 , from a workpiece 93 from a workpiece material by laser modifying and etching out the modified regions.

According to the 6A and 6B First, the workpiece 93 provided and then laser light 97 , here z. B. a laser beam 97 , generated, the laser light 97 a wavelength at which the workpiece material is substantially transparent at low light intensities (eg, at light intensities where no significant interactions - such as non-linear absorption mechanisms - of the laser light with the workpiece material occur). In the execution according to the 6A to 6D the laser beam occurs 97 from a bottom 99 of the workpiece 91 into the workpiece 91 and is on a focus position 101 inside the workpiece 91 focused.

The properties of the laser beam 97 - z. As the wavelength, the light output, the focus size and the pulse duration - are adjusted and tuned to the workpiece material that the workpiece material at the focus position 101 is modified such that the modified workpiece material compared to the original, unmodified workpiece material, an increased etch rate over an etchant 103 having. For example, the properties of the laser beam 97 be set so that the light intensity (only) at the focus position 101 reaches a threshold at which the workpiece material is converted into a brittle or porous structure due to the resulting energy input, wherein the thus modified material is the etchant 103 provides a larger attack surface and is thus selectively etched by it at a higher etch rate.

In a further process step, partial volumes 105 . 107 . 109 within the workpiece 93 with the focus position 101 of the laser beam 97 traversed, wherein the material within the sub-volumes 105 . 107 . 109 modified as described above. Each of the partial volumes 105 . 107 . 109 adjoins an outside, here on a top 111 , the workpiece 93 , In the execution according to the 6A to 6D become the partial volumes 105 . 107 . 109 - by the focus position 101 is moved three-dimensionally according to the desired shape (in 6B indicated by the arrows pointing to the left or right) - shaped such that each of the sub-volumes only via a narrow connection channel 113 with the outside or top side 111 of the workpiece 93 communicates.

The following will, as in the 6C and 6D illustrates the workpiece 93 with the etchant 103 etched, wherein the modified workpiece material within the sub-volumes 105 . 107 . 109 forming corresponding recesses 115 . 117 . 119 from the workpiece 93 is etched out. According to the in the 6A to 6D illustrated embodiment, the recesses 115 . 117 . 119 the shape of substantially closed, lying inside the workpiece cavities 115 . 117 . 119 (with a shape analogous to those with respect to the 3A to 3C . 4 and 5A to 5C described cavities), wherein the cavities 115 . 117 . 119 or lying between them, remaining workpiece material z. B. a support structure in the interior of the workpiece 93 or of the component 91 can define. From the (not weight-optimized) component 93 or mirror carrier substrate 93 thus becomes a weight-optimized mirror support substrate 95 produced.

However, it can also be provided, the partial volumes 105 . 107 . 109 in such a way that the resulting recesses have a stiffening structure with a shape analogous to that with reference to FIGS 1B and 2 described stiffening structures 13 . 19 on an outside of the workpiece 93 define.

As in 6D illustrated, in a further process step mirror surfaces 121 . 123 on the bottom 109 and / or on the top 111 of the now weight-reduced workpiece or mirror carrier substrate 95 be formed, for. By applying one or more dielectric layers to form respective dielectric mirrors 121 . 123 ,

Claims (13)

Method for producing a weight-optimized deflection mirror ( 1 ), z. B. a deflection mirror for a galvanometer scanner, comprising: - Providing a mirror carrier substrate ( 2 ) of a substrate material, - removal of substrate material on one side ( 5 ) of the mirror carrier substrate ( 2 ) forming a stiffening structure ( 13 . 19 ) in the mirror carrier substrate, characterized in that - the removal of the substrate material by means of laser light ( 9 ) he follows. The method of claim 1, further comprising: - forming a mirror surface ( 7 ) on one side ( 3 ) of the mirror carrier substrate ( 2 ), that of the for the stiffening structure ( 13 ) ( 5 ) is different. The method of claim 2, wherein forming the mirror surface ( 7 ) before forming the stiffening structure ( 13 ) he follows. Method according to one of claims 1 to 3, wherein the removal of the substrate material under the formation of such the stiffening structure ( 19 ) defining recesses ( 21 ), whose recess bottom ( 23 ) is arcuate and / or dome-shaped. Method according to one of claims 1 to 4, wherein the laser light ( 9 ) has a wavelength for which the substrate material is transparent, and wherein the removal of the substrate material by means of focusing the laser light ( 9 ) to a focus position ( 11 ) and traversing an envelope surface of a volume of the substrate material to be ablated with the focus position to release the volume along the envelope surface from the surrounding substrate material. Method for producing a weight-optimized mirror carrier substrate ( 77 ) for a deflection mirror, z. B. for a deflection mirror of a galvanometer scanner, from a workpiece ( 31 . 61 ) of a workpiece material, comprising: - forming a removal material discharge channel ( 33 . 69 ) in the workpiece ( 31 . 61 ), which is open to an outside of the workpiece, - generating laser light ( 37 . 51 . 53 . 73 ) having a wavelength for which the workpiece material is transparent, - forming a cavity ( 45 . 67 ) inside the workpiece ( 31 . 61 ) by focusing the laser light on a focus position ( 41 . 55 . 75 ) inside the workpiece ( 31 . 61 ) and method of the focus position in the interior of the workpiece in order to remove at the respective focus position by the laser light material of the workpiece, wherein the removed material ( 42 ) through the ablation material discharge channel ( 33 . 69 ) is conveyed through out of the interior of the workpiece. The method of claim 5 or 6, wherein generating laser light comprises generating a plurality of spatially separated laser beams (FIG. 51 . 53 ), and wherein the focusing of the laser light, the focusing of the plurality of laser beams ( 51 . 53 ) to a common focus position ( 55 ) having. Method according to claim 6 or 7, wherein the cavity ( 45 . 67 ) is formed with a volume which is greater than the volume of the Abtragmaterial-Abführkanals ( 33 . 69 ). Method according to one of claims 6 to 8, further comprising: - forming a mirror surface ( 63 ) on at least one side of the mirror support substrate ( 61 ). The method of claim 9, wherein forming the at least one mirror surface ( 63 ) before forming the cavity ( 67 ) he follows. The method of any one of claims 6 to 10, wherein forming the ablation material discharge channel ( 33 ) by focusing the laser light ( 37 ) to a focus position ( 41 ) on the outside ( 35 ) of the workpiece ( 31 ) and method, with material removal by the focused laser light, the focus position takes place in the interior of the workpiece. Method according to one of claims 6-11, wherein the cavity is formed in that when focusing the laser light ( 97 ) to the focus position ( 101 ) and when moving the focus position in the workpiece a partial volume ( 105 . 107 . 109 ) within the workpiece ( 93 ) is moved with the focus position to modify the workpiece material within the sub-volume such that the modified workpiece material against an etchant ( 103 ) has a higher etching rate than the unmodified workpiece material, and the workpiece with the etchant ( 103 ) is etched, wherein the modified workpiece material from the workpiece ( 93 ) is etched out. Method for producing a weight-optimized mirror carrier substrate ( 95 ) for a deflection mirror, z. B. for a deflection mirror of a galvanometer scanner, from a workpiece ( 93 ) of a workpiece material, comprising: - generating laser light ( 97 ) with a wavelength for which the workpiece material is transparent, - focusing the laser light ( 97 ) to a focus position ( 101 ) and driving off a partial volume ( 105 . 107 . 109 ) within the workpiece ( 93 ) attached to an outer surface ( 111 ) of the workpiece, with the focus position, to modify the workpiece material within the sub-volume such that the modified workpiece material is exposed to an etchant ( 103 ) has a higher etch rate than the unmodified workpiece material; Etching the workpiece with the etchant ( 103 ), wherein the modified workpiece material from the workpiece ( 93 ) is etched out.

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