METHOD AND DEVICE FOR LITHOGRAPH-BASED GENERATIVE MANUFACTURING OF A THREE-DIMENSIONAL COMPONENT

Description

[0001] The invention relates to a method for the lithography-based generative manufacturing of a three-dimensional component, in which a beam emitted by an electromagnetic radiation source is split by a beam splitter into a plurality of beams, which are focused by means of an optical imaging unit onto focal points within a material and the focal points are displaced by means of a deflection unit arranged upstream of the optical imaging unit in the beam direction, whereby volume elements of the material located at the focal points are successively solidified by means of multiphoton absorption.

[0002] The invention further relates to a device for the lithography-based generative manufacturing of a three-dimensional component.

[0003] A method for forming a component in which the solidification of a photosensitive material is achieved by means of multiphoton absorption is known, for example, from DE 10111422 A1. For this purpose, a focused laser beam is irradiated into the bath of the photosensitive material. The irradiation conditions for a multiphoton absorption process that triggers solidification are only met in the immediate vicinity of the focus, so that the focus of the beam is guided to the areas to be solidified within the bath volume according to the geometric data of the molded body to be produced.

[0004] At the respective focal point, a volume element of the material is solidified, with neighboring volume elements adhering to one another, and the component is constructed by successively solidifying neighboring volume elements. The component can be constructed layer by layer, meaning that volume elements of a first layer are solidified first, before volume elements of a subsequent layer are solidified.

[0005] Irradiation devices for multiphoton absorption processes comprise optics for focusing a laser beam and a deflection device for deflecting the laser beam. The deflection device is designed to focus the beam sequentially onto focal points within the material that lie in one and the same plane, preferably perpendicular to the direction of incidence of the beam into the material. In an x, y, z coordinate system, this plane is also referred to as the x, y plane. The solidified volume elements created by the beam deflection in the x, y plane form a layer of the component. To enable continuous operation of the deflection device, the beam is interrupted, or switched off and on again, between the solidification of two consecutive volume elements.

[0006] To build the next layer, the relative position of the focusing optics relative to the component is changed in the z-direction, which corresponds to the direction of incidence of at least one beam into the material and runs perpendicular to the x,y plane. By adjusting the focusing optics relative to the component, which is usually motorized, the focal point is shifted to a new x,y plane, which is spaced from the previous x,y plane in the z-direction by the desired layer thickness.

[0007] Structuring a suitable material using multiphoton absorption offers the advantage of extremely high structural resolution, allowing volume elements with minimum feature sizes of up to 50 nm x 50 nm x 50 nm to be achieved. However, due to the small focal point volume, the throughput of such a process is very low, since, for example, more than 10 9 points must be exposed for a volume of 1 mm 3 . This leads to very long build times, which is the main reason for the limited industrial use of multiphoton absorption processes.

[0008] In order to increase component throughput without losing the possibility of high structural resolution, it has already been proposed to vary the volume of the focal point at least once during component build, so that the component is built up from solidified volume elements of different volumes. The variable volume of the focal point enables high resolutions (with a small focus point volume). At the same time, a high writing speed (measured in mm³ / h) is achievable (with a large focus point volume). By varying the focus point volume, high resolution can be combined with high throughput. The variation in the focus point volume can be used, for example, to use a large focus point volume inside the component being built to increase throughput, and a smaller focus point volume on the component surface to create the component surface with high resolution.Increasing the focal point volume enables higher patterning throughput by increasing the volume of material solidified in a single exposure process. To maintain high resolution at high throughput, small focal point volumes can be used for finer structures and surfaces, and larger focal point volumes can be used for coarse structures and / or for filling interior spaces. Methods and devices for varying the focal point volume are described in WO 2018 / 006108 A1.

[0009] Another possibility for increasing the writing speed is to use a beam splitter to split the writing beam into a plurality of writing beams, each of which is focused into the material to be solidified, thus enabling parallel solidification of several volume elements (Kelemen et al.: "Parallel photopolymerization with complex light patterns generated by diffractive optical elements", Optics Express, Vol. 15, No. 22, pp. 14488-14497). However, the individual writing beams cannot be positioned independently of one another, so only a plurality of identical components corresponding to the number of beams can be produced.

[0010] In the field of stereolithography, it is known from US Pat. No. 5,536,467 to control a plurality of writing beams independently of one another, with each writing beam being deflected by a separate mirror to the corresponding position in the material to be solidified. However, the disadvantage is that the deflection device comprises mechanically actuated mirrors, thus limiting the scanning speed, and that the device described is not suitable for solidifying volume elements using multiphoton absorption. Furthermore, the equipment complexity increases proportionally to the number of writing beams that must be moved independently of one another. Other generic methods are known from EP2905121 A1.

[0011] The invention aims to further develop a method and a device for the lithography-based generative manufacturing of a three-dimensional component in such a way that the writing speed (measured in mm 3 / h) is further increased without restricting the component geometry and with little equipment expenditure.

[0012] To achieve this object, a first aspect of the invention provides for a method of the type mentioned at the outset to provide a spatial light modulator having a plurality of electronically controllable pixels which are scanned by the plurality of beams and which are individually switched between at least one on and one off state depending on the geometry of the component to be realized, so that the respective beam is guided to the imaging unit only in the at least one on state.

[0013] The spatial light modulator allows for simultaneous work with multiple beams, specifically multiple beams that are deflected into concurrent motion by the deflection unit. It also allows for individual control of each beam as to whether or not it should solidify a volume element at a specific position within the material. This enables parallel writing with multiple beams without each beam producing the same geometry and without requiring a separate deflection device for each beam.

[0014] Rather, the deflection unit causes all beams to be deflected together, which then scan the pixels of the light modulator at a fixed pixel pitch. The number of pixels of the spatial light modulator corresponds to a multiple of the number of beams. Since each pixel can now be switched between an on and an off state independently of the state of the other pixels, it is possible to select whether the volume element corresponding to the respective pixel should be solidified within the material or not.

[0015] The pixel is the part of the spatial light modulator whose irradiation by a beam in the on state of the pixel causes the solidification of a volume element in the material.

[0016] A significant increase in writing speed is also achieved because, due to the large number of pixels, the sum of the switching rates of all pixels is higher than in conventional systems, such as systems that use an acousto-optical modulator. An acousto-optical modulator is capable of switching a beam on and off at a rate of, for example, 50 MHz, so that 50 million volume elements per second can be written. Currently available spatial light modulators have a lower switching rate per pixel; in the case of a two-dimensional array, the entire pixel array can change its switching state at a rate of, for example, 180 Hz. However, when multiplied by the number of pixels, an extremely high writing speed results. For example, with a corresponding scanning speed of the deflection unit, a spatial light modulator with, for example, 2 million volume elements can be used.Pixels and a switching rate of 180 Hz 360 megapixels / sec can be written.

[0017] According to a preferred embodiment of the invention, the pixels of the spatial light modulator are arranged in at least one, e.g. exactly one, row running along a straight line, and the beams are split by the beam splitter along the straight line, so that the beams strike the row of pixels at a distance of a plurality of pixels from one another. The deflection of the beams by the deflection unit also takes place along the said straight line. For example, the beam splitter generates 50 beams that strike the row of pixels along the straight line at a distance of 20 pixels. The deflection unit is then controlled to deflect the 50 beams together by an angle such that the beams sweep over the 20 pixels, so that at the end of the deflection movement, every pixel of the 1000-pixel pixel row has been irradiated.

[0018] In the simplest case, a one-dimensional spatial light modulator is used, whose pixels are arranged in a single row. Such a light modulator is also called a line modulator, whereby the line modulator can be designed, for example, as a "grating light valve," i.e., a dynamically adjustable diffraction grating. A separately controllable diffraction grating is provided for each pixel. This grating grating, for example, comprises tiny metal strips that can be moved up and down electrostatically. This allows each pixel to be switched back and forth between the grating function and the reflecting mirror.

[0019] In the case of a line modulator, beam deflection around only a single axis is required. This beam deflection can be achieved, for example, by an acousto-optical deflector, which allows for extremely high deflection speed and thus a high writing speed.

[0020] Since, when using a line modulator, only volume elements of the component that are located along a straight row can be solidified, the component or material carrier must be moved transversely to the row relative to the optical imaging unit after each row in order to write another row.

[0021] According to a further preferred embodiment of the invention, the pixels of the spatial light modulator are arranged in several parallel rows. Such a light modulator with a two-dimensional arrangement of pixels allows the solidification of volume elements within the material in a two-dimensional grid without the need to adjust the component or material carrier relative to the optical imaging unit.

[0022] The beams are deflected around two axes, preferably perpendicular to each other. A fast scanner can be used for the deflection around a first axis, which corresponds to the axis normal to the beam splitting, and a slower scanner is sufficient for the deflection around a second axis. For example, the beam deflection around the first axis is performed using a resonance scanner or a polygon scanner, and the beam deflection around the second axis is performed using a galvanometer scanner.

[0023] A light modulator with a two-dimensional array of pixels can preferably be designed as a reflective liquid crystal microdisplay. Such a light modulator is also referred to as a "liquid crystal on silicon device" or "LCoS device."

[0024] The inventive use of a spatial light modulator also allows for simple pixel-by-pixel adjustment of the radiation intensity of the beam focused into the material to achieve so-called "gray scaling." A preferred embodiment of the inventive method provides in this context that the at least one on-state comprises at least a first and a second on-state, wherein the pixels are individually switched between the off-state and the first and second on-states, wherein the first and second on-states generate mutually different radiation intensities at the focal point. This grayscale function offers the advantage that the intensity of the introduced radiation can be controlled per pixel.

[0025] This can be used to achieve homogenization of the radiation output across all volume elements, i.e. to ensure that each volume element of the material is irradiated with the same radiation output. Adjusting or reducing the radiation intensity is advantageous, for example, for volume elements located at the reversal points of the beam deflection and therefore able to be irradiated for longer than volume elements in between. The same applies to volume elements or pixels that are scanned twice. In this context, a preferred embodiment of the invention provides that the radiation intensity of each pixel of the spatial light modulator is adjustable, and the radiation intensity is adjusted as a function of the exposure time of the pixels so that the volume elements receive the same radiation output.For this purpose, a suitable control unit is provided which adjusts the radiation intensity depending on the exposure time.

[0026] Alternatively or additionally, the radiation intensity adjustment can also be used to vary the radiation power at individual volume elements in order to achieve a height profile in the z-direction without changing the relative position between the imaging unit and the build platform. In this context, a preferred embodiment of the invention provides that the radiation intensity of each pixel of the spatial light modulator is adjustable, and the radiation intensity is adjusted such that volume elements receive different radiation powers in order to generate volume elements with different spatial dimensions, particularly in the direction of irradiation. The radiation power is preferably adjusted by means of a suitable control unit.

[0027] Spatial light modulators are usually designed such that the incident light beam is reflected in at least one on-state of the respective pixel. To enable the simplest possible construction, which allows the spatial light modulator to be arranged between the deflection unit and the beam splitter on the one hand, and the optical imaging unit on the other, a preferred embodiment of the invention provides that the plurality of beams are guided to the spatial light modulator with the interposition of a polarizing beam splitter. The beams are reflected from the spatial light modulator by the pixels in the on-state and, with changed polarization, impinge on the polarizing beam splitter, which guides the beams to the optical imaging unit.

[0028] In a preferred development of the above-mentioned structure, a mirror can be provided, wherein the spatial light modulator and the mirror are displaced such that either the spatial light modulator or the mirror is selectively brought into a working position arranged in the beam path. This allows switching between the inventive writing of a component using the light modulator and the conventional parallel writing of similar components.

[0029] In another embodiment, the beam splitter can be designed as a spatial light modulator that generates a static hologram or a dynamic light modulation.

[0030] Preferably, the component is constructed layer by layer with layers extending in an xy plane, wherein the transition from one layer to the next layer comprises changing the relative position of the optical imaging unit relative to the component in a z-direction perpendicular to the xy plane. The z-direction essentially corresponds to the direction of incidence of the plurality of writing beams.

[0031] A preferred procedure is when the material is applied to a material carrier, such as z.B. in a tank, and the material is irradiated from below through the material carrier, which is at least partially permeable to the radiation. A build platform can be positioned at a distance from the material carrier, and the component can be built on the build platform by solidifying the material located between the build platform and the material carrier. Alternatively, it is also possible to irradiate the material from above.

[0032] The principle of multiphoton absorption is used within the scope of the invention to initiate a photochemical process in the photosensitive material bath. Multiphoton absorption processes also include, for example, two-photon absorption processes. As a result of the photochemical reaction, the material changes into at least one other state, typically resulting in photopolymerization. The principle of multiphoton absorption is based on the fact that the aforementioned photochemical process only occurs in those regions of the beam path where a photon density sufficient for multiphoton absorption is present. The highest photon density occurs at the focal point of the optical imaging system, so that multiphoton absorption occurs with sufficient probability only at the focal point.Outside the focal point, the photon density is lower, so the probability of multiphoton absorption outside the focal point is too low to cause an irreversible change in the material through a photochemical reaction. The electromagnetic radiation can pass through the material largely unhindered at the wavelength used, and only at the focal point does an interaction between the photosensitive material and the electromagnetic radiation occur. The principle of multiphoton absorption is described, for example, in Zipfel et al., "Nonlinear magic: multiphoton microscopy in the biosciences," NATURE BIOTECHNOLOGY VOLUME 21 NUMBER 11 NOVEMBER 2003.

[0033] The source of the electromagnetic radiation is preferably a collimated laser beam. The laser can emit one or more fixed or variable wavelengths. In particular, it can be a continuous or pulsed laser with pulse lengths in the nanosecond, picosecond, or femtosecond range. A pulsed femtosecond laser offers the advantage of requiring a lower average power for multiphoton absorption.

[0034] A photosensitive material is defined as any material that is flowable or solid under construction conditions and that transitions into a second state through multiphoton absorption in the focal point volume—for example, through polymerization. The material change must be limited to the focal point volume and its immediate surroundings. The change in the substance's properties can be permanent, for example, a change from a liquid to a solid state, but can also be temporary. Even a permanent change can be reversible or irreversible. The change in the material's properties does not necessarily have to be a complete transition from one state to the other, but can also occur as a mixture of both states.

[0035] According to a second aspect of the invention, a device for lithography-based generative manufacturing of a three-dimensional component, in particular for carrying out a method according to the first aspect of the invention, is provided, comprising a material carrier for a solidifiable material and an irradiation device which can be controlled for the location-selective irradiation of the solidifiable material with at least one beam, wherein the irradiation device comprises a beam splitter for splitting an input beam into a plurality of beams, a deflection unit arranged upstream or downstream of the beam splitter in the beam path, and an optical imaging unit arranged downstream of the deflection unit and the beam splitter in order to focus each beam successively onto focal points within the material, whereby a volume element of the material located at the focal point can be solidified by means of multiphoton absorption.The device is characterized in that a spatial light modulator with a plurality of electronically controllable pixels is arranged between the imaging unit on the one hand and the beam splitter and the deflection unit on the other hand, which pixels can be scanned by the plurality of beams and which can be individually switched between at least one on and one off state, so that the respective beam is guided to the imaging unit only in the at least one on state.

[0036] A diffractive optical element can be used as a beam splitter, such as the 1D diffractive beam splitter MS-802-IYA or MS-304-YIY from HOLO / OR Ltd.

[0037] For example, an acousto-optical modulator, a resonance scanner, a polygon scanner, a galvanometer scanner or combinations thereof can be used as a deflection unit.

[0038] The beam splitter can be positioned either before or after the deflection unit. Due to the limited angular tolerance of beam splitters, positioning the beam splitter after the deflection unit is only feasible if the maximum deflection angle is relatively small. For larger deflection angles, it is preferable to position the deflection unit after the beam splitter.

[0039] According to a preferred embodiment, the spatial light modulator has a one-dimensional arrangement of pixels. In particular, the spatial light modulator can comprise a dynamically adjustable diffraction grating. As already explained in connection with the first aspect of the invention, a so-called line modulator can be used here. A line modulator is capable of changing the state of the individual pixels at a frequency of at least 300 MHz, allowing extremely high scanning and thus writing speeds to be achieved.

[0040] The deflection unit can preferably comprise at least one acousto-optic modulator, whereby the acousto-optic modulator can be arranged in front of the deflection unit. An acousto-optic modulator is an optical component that influences the frequency, propagation direction, and / or intensity of incident light. For this purpose, an optical grating is created in a transparent solid using sound waves, at which the light beam is diffracted. This can be used in designs referred to as acousto-optic deflectors to generate a beam deflection, whereby the deflection angle depends on the relative wavelengths of the light and sound waves in the transparent solid. The deflection angle can be adjusted by changing the sound wave frequency.

[0041] According to a further preferred embodiment, the spatial light modulator has a two-dimensional arrangement of pixels. In this context, the spatial light modulator can be designed, for example, as a reflective liquid crystal microdisplay. Such LCoS devices have frame rates of ≥ 60 Hz, which means that the entire pixel grid can be changed with respect to the pixel states more than 60 times per second. In the case of a layered construction of the component, at least 60 layers of volume elements can be generated in the material per second, if the time required for the layer change is not taken into account.

[0042] For scanning the two-dimensional pixel grid by the plurality of beams, it is preferably provided that the deflection unit is designed as a two-axis deflection unit and preferably comprises a resonance scanner or a polygon scanner for the beam deflection about a first axis and a galvanometer scanner for the beam deflection about a second axis.

[0043] A further preferred embodiment provides that a polarizing beam splitter is associated with the spatial light modulator, through which the plurality of beams are directed to the spatial light modulator and which deflects the beams reflected by the spatial light modulator to the optical imaging unit.

[0044] The polarization of the beams is preferably achieved by placing a retardation plate, in particular a λ / 2 or λ / 4 plate, between the polarizing beam splitter and the spatial light modulator. This rotates the polarization of the beams, resulting in an overall change of 90° at the polarizing beam splitter.

[0045] A preferred extension of the described arrangement of the light modulator consists in that a mirror is provided and that the spatial light modulator and the mirror are displaceable in such a way that either the spatial light modulator or the mirror can be brought into a working position arranged in the beam path.

[0046] Preferably, the irradiation device is designed to build up the component layer by layer with layers extending in an xy plane, wherein the change from one layer to a next layer comprises the change of the relative position of the optical imaging unit relative to the component in a z-direction perpendicular to the xy plane.

[0047] Furthermore, it can be provided that the material is present on a material carrier, such as in a tub, and the irradiation of the material takes place from below through the material carrier which is at least partially permeable to the radiation.

[0048] The build platform is preferably positioned at a distance from the material carrier and the component is built on the build platform by solidifying volume elements located between the build platform and the material carrier.

[0049] The imaging unit can be designed as an f-theta lens or preferably consists of a microscope objective and a relay optics in a 4f arrangement, with the deflection unit and the objective located in the focal plane of the corresponding lenses.

[0050] The invention will be explained in more detail below with reference to exemplary embodiments shown schematically in the drawing. Fig. 1 a schematic representation of a first embodiment of the device according to the invention, Fig. 2 a schematic representation of a second embodiment of the device according to the invention, Fig. 3 a modified version of the first and second embodiments, Fig. 4 a schematic representation of the scanning of the pixels of a spatial light modulator, Fig. 5 a representation according to Fig. 4 in a modified training and Fig. 6 a representation according to Fig. 4 in a further modified training course.

[0051] In Fig. 1 1 denotes a carrier on which a component is to be built. The carrier 1 is coated with a photopolymerizable material 2 into which laser beams are focused, with each laser beam being successively focused on focal points within the photopolymerizable material, whereby a volume element of the material located at the focal point is solidified by means of multiphoton absorption. For this purpose, a laser beam is emitted from a radiation source 3, passed through a pulse compressor 4, and deflected uniaxially by an acousto-optical modulator module 5 comprising two acousto-optical modulators 6 to perform a back-and-forth movement. The zero-order beam is collected in a beam trap 7.The first-order beam is guided via a relay system 8 to a beam splitter 9, which splits the beam into a plurality of beams, which are then guided via a scanning lens 17 to a polarizing beam splitter 10. The polarizing beam splitter is configured to transmit the plurality of beams toward a spatial light modulator 11. The beams pass through a retardation plate 12, which retards a polarization component relatively, for example, by λ / 4. The polarization of the beams reflected by the spatial light modulator 11 is rotated again in the retardation plate 12, so that upon impinging on the polarizing beam splitter 10, they are redirected toward the optical imaging unit 13. The beams reach the optical imaging unit 13 via a tube lens 14.The optical imaging unit 13 comprises a lens which focuses the laser beams into the material 2 within a writing area.

[0052] During training according to Fig. 1 The spatial light modulator 11 is designed as a line modulator and comprises a plurality of pixels arranged in a row. Each pixel can be switched between an on and an off state, for example, by an electronically controllable diffraction grating, so that the respective beam is only reflected in the on state to the polarizing beam splitter 10 and subsequently guided to the optical imaging unit 13.

[0053] The beam splitter 9 is designed to generate a plurality of beams distributed along the pixel row, and the deflection unit 5 is designed to collectively shift the plurality of beams along the pixel row, i.e., to scan the pixel row. Depending on whether the respective pixel is in the on or off state, the beam is reflected by the light modulator and introduced into the material 2 at the corresponding location.

[0054] After scanning the pixel row and generating corresponding solidified volume elements in the material 2, which are arranged, for example, in a row running in the y-direction, the next row is switched to by arranging the carrier 1 on a cross table that is displaceable in the x-direction relative to the optical imaging unit 13. In this way, volume elements can be generated in a plurality of rows. This is shown schematically in Fig. 4 shown.

[0055] Fig. 4 a row 23 of pixels 24 is shown, which extends, for example, in the x-direction. In the present example, the beam splitter generates two beams 25, which are arranged at a mutual distance of six pixels. The deflection device causes this group of two beams 25 to be moved according to the arrow 26 and in this way scans the pixel row 23. At the locations represented by the dark-colored pixels, a volume element is to be solidified. This is achieved by switching these pixels in the light modulator to the on state. After scanning the row 23, the carrier 1 is shifted by one unit in the y-direction so that, in addition to the previously solidified volume elements, further volume elements can be solidified, as indicated by the arrow 29. When scanning the pixel row, other pixels are now switched to the on state, so that after a plurality of rows, the Fig. 4 shown pattern is created.

[0056] To build the component layer by layer, volume elements of one layer after another are solidified in the material 2. To build a first layer, the laser beams are focused one after the other onto focal points within the material 2, which are arranged in the focal plane of the optical imaging unit 13. To move to the next plane, the optical imaging unit 13, which is attached to a carrier 15, is adjusted in the z-direction relative to the carrier 1 by the layer spacing. Alternatively, the carrier 1 can also be adjusted relative to the fixed optical imaging unit 13.

[0057] Furthermore, a control unit 16 is provided which controls the deflection unit 5, the beam splitter 8, the light modulator 11, the height adjuster 15 and the carrier 1 attached to the cross table.

[0058] During training according to Fig. 2 In contrast to the embodiment according to Fig. 1 a two-dimensional pixel grid. Therefore, a deflection unit 19 is provided, which is capable of deflecting the plurality of beams generated by the beam splitter 9 around two perpendicular axes. For this purpose, the deflection unit 19 has a first scanner 20 and a second scanner 21, which are controlled such that the first scanner scans one pixel row at a time (in the x-direction), as in connection with the embodiment according to Fig. 1 and the second scanner deflects the beams transversely (in the y-direction) from one row to the next. Another difference to the design according to Fig. 1 is that the deflection unit 19 is arranged after the beam splitter 9. Furthermore, an acousto-optical modulator 18 is arranged before the beam splitter 9, which serves to set the global power limit and limit the power at the turning points of the scanner to avoid damage to the modulator.

[0059] Due to the use of a spatial light modulator 11 with a two-dimensional pixel array, volume elements can be generated within a two-dimensional writing area of ​​the optical imaging unit 13. If the component to be manufactured is larger in the x- and / or y-direction than the writing area of ​​the optical imaging unit 13, substructures of the component are built up next to each other (so-called stitching). For this purpose, the carrier 1 is arranged on a cross table that is displaceable in the x- and / or y-direction relative to the optical imaging unit 13.

[0060] The training according to Fig. 3 differs from the training according to Fig. 2 in that instead of the spatial light modulator 11, a mirror 22 can be brought into the beam path if the functionality of the light modulator 11 can be dispensed with.

[0061] The scanning of the two-dimensional pixel grid of the spatial modulator is in Fig. 5 und Fig. 6 Here, the individual pixels are again designated 24 and it is evident that the pixels 24 are arranged in several rows, ie in a two-dimensional arrangement. In the embodiment according to Fig. 5 The beam splitter generates four beams 25 in a square arrangement, whereby the individual beams are moved two-dimensionally across the pixel grid by means of the deflection device along the path designated by 28. The beam deflection in the direction of the double arrow 26 (x-direction) is carried out, for example, by means of an acousto-optical deflector, and the beam deflection in the direction of the double arrow 27 (y-direction) is carried out, for example, by means of a galvanometer scanner. By switching between the on and off state, the Fig. 5 The pattern shown is generated, whereby a volume element is solidified at the locations represented by the dark-colored pixels (on state).

[0062] In the version according to Fig. 6 The beam splitter generates three beams 25 in a linear arrangement, with the individual beams being moved two-dimensionally across the pixel grid by means of the deflection device along the path designated by 28. The beam is deflected in the direction of the double arrow 26 (x-direction), for example, by means of a resonance scanner, and the beam is deflected in the direction of the double arrow 27 (y-direction), for example, by means of a galvanometer scanner.

Claims

1. Method for lithography-based generative manufacturing of a three-dimensional component, in which a beam emitted by an electromagnetic radiation source (3) is split with a beam splitter (9) into a plurality of beams which are focused by means of an optical imaging unit (13) onto focal points within a material (2) and the focal points are displaced by means of a deflection unit (5, 19) arranged upstream of the optical imaging unit (13) in the beam direction, whereby volume elements of the material (2) located at the respective focal points are successively solidified by means of multiphoton absorption, characterized in that a spatial light modulator (11) is provided with a plurality of electronically controllable pixels which are scanned by the plurality of beams and which are switched individually between at least one on-state and an off-state depending on the geometry of the component to be realized, so that the respective beam is guided to the imaging unit (13) only in the at least one on-state.

2. Method according to claim 1, characterized in that the at least one on-state comprises at least a first and a second on-state, wherein the pixels are individually switched between the off-state and the first and the second on-state, wherein the first and the second on-state generate different radiation intensities at the focal point.

3. Method according to claim 1 or 2, characterized in that the radiation intensity of each pixel of the spatial light modulator is adjustable and the radiation intensity is adjusted depending on the exposure time of the pixels in such a way that the volume elements receive the same radiation power.

4. Method according to claim 1 or 2, characterized in that the radiation intensity of each pixel of the spatial light modulator is adjustable and the radiation intensity is adjusted in such a way that volume elements receive different radiation power from one another in order to produce volume elements with different spatial dimensions from one another, in particular in the direction of irradiation.

5. Method according to any one of claims 1 to 4, characterized in that the pixels of the spatial light modulator (11) are arranged in at least one, e.g. exactly one, row extending along a straight line and the splitting of the beams is carried out by means of the beam splitter (9) along the straight line, so that the beams impinge on the row of pixels spaced apart by a plurality of pixels.

6. Method according to claim 5, characterized in that the pixels of the spatial light modulator (11) are arranged in a plurality of parallel rows and the plurality of beams are deflected about two axes which are preferably perpendicular to one another, the beam deflection about a first axis preferably being effected by means of a polygon scanner or resonance scanner (21) and the beam deflection about a second axis preferably being effected by means of a galvanometer scanner (20).

7. Method according to any one of claims 1 to 6, characterized in that the plurality of beams are directed to the spatial light modulator (11) with the interposition of a polarizing beam splitter (10), the beams are reflected by the spatial light modulator (11) and impinge with changed polarization on the polarizing beam splitter (10), which directs the beams to the optical imaging unit (13).

8. Method according to any one of claims 1 to 7, characterized in that a mirror (22) is provided and in that the spatial light modulator (11) and the mirror (22) are displaced in such a way that either the spatial light modulator (11) or the mirror (22) is brought into a working position arranged in the beam path.

9. Method according to any one of claims 1 to 8, characterized in that the component is built up layer by layer with layers extending in an x-y plane, the change from one layer to a next layer comprising the change in the relative position of the optical imaging unit (13) relative to the component in a z direction running perpendicular to the x-y plane.

10. Device for lithography-based generative manufacturing of a three-dimensional component, in particular for carrying out a method according to any one of claims 1 to 9, comprising a material carrier (1) for a solidifiable material (2) and an irradiation device which can be controlled for position-selecitve irradiation of the solidifiable material with at least one beam, wherein the irradiation device comprises a beam splitter (9) for splitting an input beam into a plurality of beams, a deflection unit (5, 19) arranged upstream or downstream of the beam splitter (9) in the beam path and an optical imaging unit (13) arranged downstream of the deflection unit (5, 19) and the beam splitter (9), in order to focus each beam successively onto focal points within the material (2), whereby a volume element of the material (2) located at the respective focal point can be solidified by means of multiphoton absorption, characterized in that between the imaging unit (13) on the one hand and the beam splitter (9) and the deflection unit (5,19) on the other hand, a spatial light modulator (11) with a plurality of electronically controllable pixels is arranged, which can be scanned by the plurality of beams and which can be switched individually between at least one on-state and an off-state, so that the respective beam is guided to the imaging unit (13) only in the at least one on-state.

11. Device according to claim 10, characterized in that the at least one on-state comprises at least a first and a second on-state, wherein the pixels are individually switchable between the off-state and the first and the second on-state, wherein the first and the second on-state generate different radiation intensities at the focal point.

12. Device according to claim 10 or 11, characterized in that the spatial light modulator (11) comprises a one-dimensional arrangement of the pixels.

13. Device according to claim 10, 11 or 12, characterized in that the spatial light modulator (11) comprises a dynamically adjustable diffraction grating.

14. Device according to any one of claims 10 to 13, characterized in that the deflection unit (5) comprises at least one acousto-optical modulator.

15. Device according to claim 10 or 11, characterized in that the spatial light modulator (11) comprises a two-dimensional arrangement of the pixels.

16. Device according to claim 15, characterized in that the spatial light modulator (11) is designed as a reflective liquid crystal microdisplay.

17. Device according to claim 15 or 16, characterized in that the deflection unit (19) is designed as a two-axis deflection unit and preferably comprises a polygon scanner or a resonance scanner (21) for beam deflection about a first axis and a galvanometer scanner (20) for beam deflection about a second axis.

18. Device according to any one of claims 10 to 17, characterized in that a polarizing beam splitter (10) is assigned to the spatial light modulator (11), through which the plurality of beams is directed onto the spatial light modulator (11) and which deflects the beams reflected by the spatial light modulator (11) to the optical imaging unit (13).

19. Device according to claim 18, characterized in that a waveplate (12), in particular a λ / 2 or λ / 4 plate, is arranged between the polarizing beam splitter (10) and the spatial light modulator (11).

20. Device according to any one of claims 10 to 19, characterized in that a mirror (22) is provided and in that the spatial light modulator (11) and the mirror (22) can be displaced in such a way that either the spatial light modulator (11) or the mirror (22) can be brought into a working position arranged in the beam path.

21. Device according to any one of claims 10 to 20, characterized in that the irradiation device is designed to build up the component layer by layer with layers extending in an x-y plane, the change from one layer to a next layer comprising the change in the relative position of the optical imaging unit (13) relative to the component in a z-direction perpendicular to the x-y plane.