HK1213528B - Device and method for producing three-dimensional structures - Google Patents

Description

The present invention relates to a device and a process for the production of three-dimensional structures, such as body or surface structures, from a material to be solidified, in particular from an organopolysiloxanthin material, by the selective solidification of the material by light-induced organic cross-linking.

It is known from the state of the art to produce three-dimensional body or surface structures e.g. by light-induced processes, especially by organic networking, by first producing only one layer or plane as a two-dimensional component of the structure to be created and the three-dimensional structure of the body or surface structure is constructed by successive processes of successive two-dimensional layers or planes. Examples of such two-dimensional working processes are stereolithography, selective laser internal (SLS) or 3D printing (3DP).

In a special variant of stereolithography, the exposure is made through the transparent bottom of the bath to avoid interaction of the resulting body with the gas atmosphere above the bath surface, e.g. an oxidation reaction. The liquid material is solidified in the immediate vicinity of the bottom of the bath. To prevent the solidifying material from sticking to the floor, it must be coated with a non-soluble liquid as a separating layer, it must be DE 41 02 260 A1, Claim 13. This makes the process difficult to control, as the solidified fluids must be moved in the bath between the bottom of the bath and the last layer of the bath, thus preventing the solidification of the body.

Faster processes offer three-dimensional methods in which material modifying radiation directly interacts in the volume of a raw, solid or liquid starting material. Two-photon or multiphoton polymerization is known from WO 03/037606 A1 for the solidification of organopolysiloxane-containing materials (polymerization is done by two-TPA or multiphoton absorption).

A disadvantage of known three-dimensional processes and devices for their implementation is that structures can be produced, especially with high precision requirements, only with limited sizes in the micrometer range. This disadvantage is due to the small working distance of the optics required to achieve sufficient precision, i.e. the distance between the focal plane and the exit lens of the optics, which is usually variable and depends on the numerical aperture of the optics used.In order to allow exposure under defined conditions, a defined boundary surface must be exposed. In the case of material arranged between two plates, the exposure is by one of the two plates from above or from below. In the case of an open carrier, the exposure is by the bottom of the carrier. The disadvantage is that no larger structures can be solidified, since due to exposure by or through the carrier material on the optically opposite side of the same can only be solidified at a limited distance determined by the working state of the optics.

In WO 92/00185, a special variant of device concerns a vertically (i.e. along the optical axis) moving focusing optics with a high numerical aperture which, in order to avoid errors caused by liquid-air interface surfaces, is immersed in a bath with the same solidifying material intended as the bath material for the production of the solidified body.

DE 101 11 422 A proposes a similar method of arranging the bathtub on a table which can be walked on in the X-Y plane and providing a platform which can be walked on in the Z direction in order to position the focal point (focal area) in a suitable way. The exposure is taken from above into the open bath surface. Alternatively, the focus is moved in the X and Y directions by means of a scanning device, i.e. with one or more moving mirrors. This system does not allow the use of a high numerical aperture of the optics and thus does not achieve a high structural resolution when simultaneously displaying free body sizes.

Based on the state of the art described above, the present invention is intended to create a device and a process for the production of three-dimensional bodies or surface structures by location-selective solidification of a material as a result of light-induced organic interconnection, which essentially allows the production of bodies and structures of any shape, in particular with dimensions and heights in the millimetre and centimetre range, preferably with shortened production times and correspondingly high resolution, low material flow and high accuracy and repeatability. In particular, the invention is intended to enable the production of large bodies with very high accuracy.

On the device side, this task is solved by a device according to claim 1 for the production of three-dimensional structures from a material to be solidified, in particular from an organopolysilicon material.

The method is solved by a method according to claim 9 to produce three-dimensional structures from a material to be solidified.

Unlike the devices and methods known from the state of the art, the limiting effect of the working distance of the focusing optics is overcome by their positioning and, if necessary, that of the supporting platform in the bathroom relative to the focal point (s) of the optics (optics) in the Z-direction.However, only lenses with a low numerical aperture (NA) (< 0.25) or simple lenses and so-called F-Θ lenses have such large apertures. Due to the low numerical aperture, these reduce both the axial (Z) direction of the structure resolution and the lateral resolution of the eye (depending on the actual conditions on voxels with a length (in the Z direction) of 0.5 to 1 mm). This compensates for the real advantage of 2- and multiphoton polymerization, namely the production of small very minimal structural sizes, and it is not possible to produce high-resolution structures, as is required for example for biomedicine (e.g. porcelain Scaffold) or optical construction.Err1:Expecting ',' delimiter: line 1 column 348 (char 347)Err1:Expecting ',' delimiter: line 1 column 335 (char 334)In order to produce large structures, the state-of-the-art multiphoton structure generally involves deliberately renouncing good resolution, firstly because a higher resolution is obtained with a larger structure width and secondly because a high working distance (i.e. the distance of the lens's output to the focal point) is the prerequisite for the structure to be sufficiently large (the structure cannot be larger than the working distance).

In contrast, a lens with high NA can be used for the invention-based body construction, even if large moulds are to be produced. Because these moulds are to be produced independently of the working distance, according to the invention. Therefore, it is possible to freely choose whether to create fine, high-resolution structures or - by increasing the laser power - also wide lines and thus achieve an increased build rate (the lines become wider as the laser power increases, because the consolidation conditions are met in a wider space (sword wave process)).

Most lenses have the best imaging properties only in a specific focal area. If they come from the microscope, this is usually located at the bottom of the cover glass (corresponding to the inside of the bathtub wall). Any deviation from this point leads to image errors and thus to a smearing of the focal point in the room. According to the invention, it is therefore preferable to choose the distance of the lens from the bathroom and thus the location of the focusing planes in such a way that as little as possible of the to be solidified bathroom material has to pass through.

The invention is intended to be used with any type of lens, with or without immersion.

The invention is intended to produce three-dimensional structures with dimensions up to and including the centimeter range. In the first case, the focusing device can be placed in the material to be weakened without restriction by immersion and positioning the focusing device in the material. In the second case, the focusing device can be placed relatively close to the material and thus the material to be fixed and positioned in a position that is usually closer to the material, but in the third case, the focusing device can be placed in a position that is closer to the material already fixed.

Since the laser beam is always passed through a defined boundary, i.e. a transparent, optical surface, into which the material to be solidified is introduced, optical errors are kept very low. A solidification can be carried out with a very high precision, regardless of the amount of material to be solidified and the size of the material pool. The achievable resolution, which is mainly determined by the focal length, focusing optics and a threshold process in the material, is further high and is not greatly impaired by optical errors in the introduction of the radiation into the material.

The present invention is particularly suitable for the rapid manufacture of specific and randomly shaped functional elements on randomly shaped substrates, e.g. planar or cylindrical. These include, for example, optical elements for applications in the field of (bio) photonics and antireflection layers. It is also possible to manufacture photonic crystals for future photonic circuits and components in parallel. In addition, the structures produced with the device can be used in micro-mechanics (as MEMS or MOEMS) and micro and nanoelectronics, as well as in quantum building elements and polymer electronics.

A material to be solidified within the meaning of the invention is an organic material or an inorganic-organic hybrid material, in particular an organopolysilicon-containing material, which can be photochemically solidified. The material to be solidified may be, for example, a material filled with nano- or microparticles or an unfilled material. Filled materials contain certain, possibly unbound, additive materials that can give the material certain desired properties.

The bath material to be solidified can be treated either solvent-free or solvent-containing. In the latter case, the type of solvent used is not critical; non-toxic solvents are however beneficial, for example if the structures to be produced are to be used in medicine or related fields. If no solvent is used, the bath material may have a very high viscosity depending on the polysiloxane used, which is usually produced by polycondensation of one or more organically polymerizable silanes.

Working with a solvent-free bath material has a number of advantages, such as the fact that the structures produced do not contain small molecules, potentially toxic or otherwise hazardous compounds.

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The removal of the produced bodies can be done simply by removing them from the bath, for example by driving the carrier out of the bath, then, if necessary, washing them with an appropriate solvent to remove adhesive bath material and drying them in the air or by other means (e.g. in a protective gas atmosphere).

The invention makes it possible to produce three-dimensional bodies of any shape from materials to be hardened by light-induced interconnection processes over a wide wavelength range using a variety of laser and optical systems in situ.

A laser pulse sequence or series of laser pulses is a number of consecutive single laser pulses used to solidify a structural unit (voxel). The number of pulses is at least two, preferably 100 to 1000 or more, 100 to several thousand. The laser pulse or series of focused laser pulses is then directed directly at an addressed volume element in the material to be solidified.A material change can be triggered in this way very specifically in three-dimensional space. With particular advantage, laser pulses of a duration in the femtosecond range are used. The radiation used has the advantage of having a wavelength that under normal circumstances, when the energy of a photon is not sufficient to excite atoms or molecules, is not absorbed into the reactive material. Unlike other structuring methods, such as classical rapid prototyping with stripper and overlay, the present invention offers the advantage that three-dimensional structures can be produced in one step with a material flow wall and in a very short time, whereby the structures can be produced at almost any size with high precision.

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The positioning is initially such that the focus or the focuses are or become positioned near the support unit or adjacent to it. Initially solidified material accumulates on the support unit as part of its solidification and is positioned with it relative to the focus or the focus during the further course of structuring or solidification. The further positioning is such that material accumulates on already solidified material or the support unit.

When the laser beam is passed through the material container into the material to be solidified, this is itself used to form a defined boundary layer at which the laser beam enters the material to be solidified.

When laser radiation is introduced through the wall or bottom of the material container, it has the particular advantage that no contact is made between the optics and the solidifying material. This allows a quick process and positioning of the optics. No turbulence is generated in the material and there is less resistance than when positioning a submerged optic. Furthermore, the optics do not need to be sealed against the material to be solidified.

In the case of a focusing optic that is submersible in the material, this optic itself forms a defined optical boundary for the laser beam entering the material to be solidified. Unlike the above embodiment, solidification can be carried out at any point in the material bath without the need for an additional positionable support unit, since the optic can be positioned in the material bath in the desired way and almost any depth and the place of solidification is not limited by the working distance of the optic.

In one design, a device according to the invention has an optics for spatially splitting the laser beam and generating at least two spatially separated laser focuses or intensity maxima, hereinafter referred to as parallelisation. This allows the radiation energy of the laser to be directed simultaneously to two or more voxels in space, so that a solidification occurs simultaneously at two or more points. Relatively large structures and moulds can thus be produced in a short time.

In the case of parallelisation, the invention allows not only the parallel generation of voxels of a single functional element, but also the parallel generation of two or more functional elements. A single structure may be simultaneously generated via several focal points or multiple structures may be simultaneously generated via one or more focal points. One or more optics may be used to generate n foci. It is possible to produce several structures on the same substrate, as well as to choose a separate substrate for each structure.

Parallelisation can be further achieved by beamforming or splitting a laser beam into several sub-beams, each of which is then focused and solidifies voxels in the material at several points at the same time. For this purpose, for example, an amplitude mask can be used, which is brought into the beam gap and generates a deflection pattern in the beam's far field. In addition, a microlens array, an axis lens, for example, can be used to generate a ring-shaped burning plane or an electrically controllable spatial light modulator as a dynamically variable phase mask, which allows a targeted distribution of light intensity into several focal points and thus a partial parallelisation of the structure.

The device of the invention has a positioning system by which the laser focus or laser focuses can be positioned in the material bath. The positioning is performed by a movement of the focus optics, if necessary supplemented by a movement of a support unit located in the bath. It can be done in the form of linear and/or rotary positioning in and/or around one, two, three or more axes. In particular, a support unit for solid material can be movable, especially linearly moveable and/or rotatable relative to the laser focus. Because the material container does not have to be moved, only relatively small masses can be accelerated and slowed, which results in a high-strength positioning. The rotating unit can be moved in all configurations, even in two or more of the three rooms.

In any case, positioning is achieved by moving the optics. It can be moved in one spatial direction, e.g. in the Y direction if the carrier in the material bath is at least X- and Z-movable. Preferably, however, the focus optics can be moved in at least two spatial directions, e.g. in X- and Y-direction, while the carrier can be moved at least Z-direction.

The position of at least one focal point relative to the material to be solidified can be freely chosen. This allows different starting points for material modification to be addressed. In the case of multiple laser focuses, a focal plane is defined for all focal points whose position or location in the material to be solidified can be addressed. However, when using an active, dynamic spatial light modulator, the relative position of the focal points to each other can also be dynamically varied.The following: Other In the (multi-photon) structuring of liquid materials, the curing of the liquid material directly on the surface of the substrate is important. This requires an anchor point so that the next volume element to be solidified (voxel) is in contact with an already solidified area or the substrate itself. If this is not the case, already solidified areas in the liquid resin can drift away from their intended position, which affects the structural quality. This can lead to a defective structure.The invention is therefore of particular interest in the case of the invention of a single anchor point (or several anchor points, if any).

In a first design, this anchor point is detected by means of a microscope camera installed in the system, which is pointed at the surface to be structured and which, in addition to the resulting structures, also allows the laser spot to be observed.

In a second design, the anchor point can be found automatically, by measuring the sample already in the bath or the substrate in situ with a detection system (of any type), and the data on the substrate surface obtained are used to determine the anchor point for each structure individually, either when writing several structures on a substrate, or when writing a single (large) structure, adjusting its geometry so that it always has a defined orientation to the substrate surface as far as possible.

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These measures can be used in both cases: firstly, to find the correct anchorage point, even in the most common case of a slightly bent substrate, of course also in the case of a bent substrate; secondly, to re-structure already textured surfaces, for example, to apply additional structures to previously textured lenses.

A single point sensor is explained in more detail below as an example. A voltage signal is generated depending on the position of the focal area relative to the substrate or the target anchor point. This should reach a certain level, preferably a maximum, when the anchor point meets the focus. This can be achieved, for example, by the method of reflection in the beam path, as shown in Fig. 12. Before the insertion of the structuring laser or the pulse, these pass through, for example, a glass plate, which is initially not relevant for the propagation of this pulse. The radiation is then re-focused back into the material as usual.

In one variant, such a topographic image can be obtained by repeating this maximization of the reflection at many points on the substrate and storing the Z-positions at which the maxima occur. For the reflex method, the laser used for the structuring may be used as a radiation source. In this case, its power is advantageously set very low to eliminate the risk that the light beam intended for the reflection will cause an unwanted solidification of material.

Because the focus is moved relative to the substrate in the XY plane and the focus position in Z relative to the substrate is changed, the difference from the set value (the voltage signal at maximum) to the (dynamic) current value must be adjusted. Mathematical calculations are performed to transmit a signal to the control (the Z axis) that approximates the set value to the set value. The specialist is able to perform these calculations (usually proportional (P), integral (I) and differential selection operations (D)) and adjust the parameters so that an accurate adjustment of the set value is made.

A PI controller combines the advantage of the P controller, namely fast response, with the advantage of the I controller, exact tuning. A PI controlled circuit is therefore precise and medium-fast. A PID controller combines the good properties of all three types of controller. The PID controlled circuit is precise and very fast.

The positioning accuracy of at least one or each axis of motion is preferably at least 0,20 μm. Using positioning systems in the form of highly precise linear tables, e.g. air-launched or piezo-movable, with large travel paths and optionally large substrates or material baths (e.g. 62 cm x 62 cm), both small structures with dimensions of less than one millimeter and macroscopic bodies with several centimetres of sound can be produced.

In a particularly advantageous embodiment, a positioning device with at least one rotatable axis can be used instead of or in addition to linear positioning in the planes of the room, which allows either the material to be solidified or a support unit immersed in it to be rotated by at least one spatial axis. Substrate in the form of rolled-up films or similar can be used, which then act as a support unit or are positioned by means of such a support unit. The film-like substrates can be guided through rotational positioning and positioned relative to the laser focus at least one second. The rotational positioning is carried out with a resolution of at least 0.079 arcseconds and precision of at least 3 arcseconds. The maximum rotational speed of the rotation is less than 300 microseconds per minute.

The positioning system has the following special advantages: the path of movement is preferably at least 150 mm in each direction, especially in each direction of space; the positioning accuracy is preferably ±0.20 μm in each direction; the accuracy in repeated approach to a point is ±0.05 μm; the accuracy perpendicular to the direction of movement in the horizontal plane is in particular ±0.25 μm and the accuracy perpendicular to the direction of movement in the vertical plane is ±0.25 μm. The speed of the positioning system is up to 300 mm/s (lower speeds are also possible), with a maximum acceleration at a linear load of approx. 10 m/s.^{2 and}- I 'm not .

The advantage of Ytterbium lasers over Ti-Saphir laser systems, which have a wavelength of approximately 800 nm, is the wavelength of 1030 nm. This is at a frequency doubling in the range of 515 nm, which can result in a very high pulse rate, resulting in a very high resolution. In addition, the structural materials can be processed more efficiently than a laser process that would use a laser pulse rate of approximately 800 nm. This is most likely due to the fact that the most efficient and most cost-effective laser process can be achieved with a laser pulse rate of approximately 1 nm.

Finally, it is possible to use Ytterbium laser systems in principle. The advantage is that you can pump these lasers with diodes and no additional pump laser and various other instruments are necessary. The advantage of Ytterbium lasers over Nd:YAG lasers, however, is relatively short pulses. While Ytterbium lasers can achieve pulses well below a picosecond, the pulse lengths of a Nd:YAG laser are usually greater than a picosecond and thus rather unfavorable to trigger a nonlinear absorption, as there is a danger of weakly networked and unstable structures, which can lead to the previously described nights.

The pulse durations required to efficiently induce non-linear absorption are less than one picosecond. To improve light-matter interactions and to stimulate polymerization more efficiently, photoinitiators may be used in addition. The repetition rate is preferably between 1 kHz and 80 MHz, preferably between 10 kHz and 80 MHz.

The device of the invention can be used to produce any intensity distribution, such as multiple focus points or any spatial beamforming, which allows the writing of any structure with several shaped bridging points, if any. The use of passive DOE (differential optical elements), such as phases or amplitude masks, or micro lens arrays, or active, preferably dynamically adjustable DOE, and combinations thereof, can thus produce any intensity distribution, such as multiple focus points or any shaped focus points, which allows the writing of any structure with several shaped bridging points, if any.

The use of multiple focus optics requires the division of the laser power by conventional beam splitters into several beams, each of which is led to a focus optics. Finally, a combination of the above beam formations is possible by first generating a modulator to produce the desired intensity distribution of the radiation and then focusing it through several optics.

Each focusing optic can be moved in relation to other elements of the beam line and/or the material container and/or the material to be solidified and/or the support unit, so that only the focusing optic alone needs to be moved to position and the remaining beam line elements can be fixed.

To avoid image errors in focusing, hybrid optics made of diffractive optical elements and conventional lenses can be used after the invention. The diffractive optical elements are made of, for example, quartz glass, organopolysiloxanthin-containing materials, liquids or any combination of materials. When using focus optics, which are used without refractive adjustment, a positioning error is obtained at variable depths of light penetration into the material due to refraction at the air-material interface (i.e. the movement of the focal point does not coincide with the movement of the optics).

The device and method of the present invention are not limited by the deflection limitations of the focusing optics, because on the one hand there is a different absorption behavior than in linear single-photon absorption and on the other hand a threshold process is used. The absorption profile (approximately Gauss profile) in multiphoton absorption is still narrower, which allows a better resolution, since there is a nonlinear relationship between the photon density and the absorption behavior. While the absorption behavior of the photon absorption structure is characterized by a very high linearity compared to the photon density and can be explained by classical physics, the absorption of two or more materials in the background of the multiphoton absorption is limited.

In another embodiment of the invention, the device may have a dispenser system for deposition of the material to be solidified in situ. Such a system has the advantage that material to be solidified can be added to the material bath in accordance with the process state. This has the positive effect, in particular in the manufacture of large bodies or structures down to the millimetre or centimetre range, that at the beginning of the manufacture only as much material must be present in the material as is necessary to produce the first voxel.preferably only in the quantity necessary to produce the next voxel. In this way, the bath is always filled with only the quantity of solidifying material necessary to produce voxels at the moment, which has the advantage that only a relatively small mass has to be moved when the bath is positioned and that when the bath is positioned by a movement of an optical device immersed in the material, it does not have to be moved deeply into the material, thus largely preventing current resistance and swirling in the bath, which has a positive effect on the quality of the bodies produced.The dispense system preferably has a high positioning accuracy in the micrometer range. The above described procedure management is in principle possible even without the use of a dispense system.

According to another proposal, the device may have a scanning system, in particular a 3D scanner, or it may be used in the process. In this way, any molded template or body can be digitized and the resulting data used to easily write complex shaped bodies and structures directly in the machine into the material to be solidified. In particular, the structures produced with the device can be used as a master structure for further molding techniques.

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In Fig. 1 a device for the purpose of illustrating the invention is shown schematically. The device according to this figure has a laser source 1, a refocus mirror 2 as part of a beam guide and a focusing optics 3. The unfocused laser beam 4 emitted from the laser source 1 is directed through the refocus mirror 2 to the focusing optics 3.

Below the focusing optics 3 the material to be solidified 6 is placed between a lower support 7 and an upper support 8. As shown schematically in Fig. 1, the material intake consisting of the lower support 7 and the upper support 8 can be positioned in the X and Y directions relative to the focus 5 and the focusing optics 3 with the intermediate material to be solidified 6 and the focusing optics 3 relative to the material 6 in the Z direction.

Fig. 1 shows the arrangement of the focusing optics 3 relative to the material 6 to be fixed at the beginning of a fixation cycle. The focus 5 is adjacent to the lower support 7 so that material solidified in the focus area attaches to support 7. This initial positioning is necessary to fix the material in a positioning-able position during further fixation, as otherwise no defined structures can be constructed. To achieve this initial positioning of the focus, the distance between the respective upper surface of the lower support 7 and the upper support 8 must be less than the working distance 9 of the focusing optics 3. Otherwise, the focusing optics 5 can be positioned in the support 7 and fixed there in a positioning-able manner. However, in the case of a fixed structure, a greater distance between the support 9 and the working distance 8 may not be possible, so that the working distance between the support 9 and the support 8 is not greater than the working distance 8 of the support.

Fig. 2 shows a first embodiment of the invention in which exposure of the material to be hardened is made through a material container 10. In the case shown, the material container 10 is exposed from below through the bottom 11 of the material container 10 by directing an unfocused laser beam 4 generated in the laser source 1 through a focusing mirror 2 to a focusing optic 3 located below the material container 10. The focusing mirror 2 can be positioned. The beam is focused from this into the material to be hardened contained in the material container 10. As with the device, the maximum depths at which the focusing optic can be introduced into the material to be hardened 6 are obtained by the 9th tritaxel, while the focusing effect is limited to the 12th tritaxel. In the case of Fig. 10 the focusing effect is limited to the 12th tritaxel.

Figure 2 also shows an example of the beginning of the production of a structure. The support unit 12 is positioned so that the focus is adjacent to material container 10 and the focus 5 so that the focus is adjacent to the lower surface of the support unit 12. In the area of the focus 5, the solidified material separates at the bottom of the support unit 12 and adheres to it. Depending on the dimensions of already solidified volume elements, the support unit 12 can be positioned in the Z direction so that the focus is on a boundary solidified material and subsequently the already mounted material is attached to and attached to the already solidified material.

Fig. 5 shows another device in a further schematic representation. The device again has a laser source 1, whereby a laser beam 4 from this outgoing unfocused laser beam is directed via a reversing mirror 2 to a focusing optic 3. It also has a material container 10 with material 6 to be solidified and a carrier unit 12. This is not drivable in the example shown, but can be positioned in one or more directions.

The focusing optics 3 has a housing 14 with a beam output surface 13 and can be positioned in the three spatial directions X, Y and Z in the example shown. By immersing the focusing optics 3 its beam output surface 13 forms an optically defined interface to the material to be solidified 6, which allows a defined and precise introduction of the laser radiation into the material to be solidified 6.

Figure 5 shows the device again at the beginning of a structuring process, in which the focusing optics 3 is placed at working distance 9 relative to the support unit 12 so that the focus 5 is adjacent to the surface of the support unit 12. By corresponding positioning in the X and Y directions, the fixation and attachment in the X and Y directions respectively is determined. After initial fixation on the support unit 12, the structuring can be performed by corresponding positioning of the focusing optics 3 in the Z direction, in accordance with the strength of the material already attached and adhering to the support unit 12.

The present invention uses a high NA focusing optics 3 for all possible embodiments, at least with an NA greater than 0.25 to achieve the desired high resolution or small voxel. The working distances 9 of the lenses are preferably between 0.1 and 100 mm, more preferably between 1 and 10 mm. It should be emphasized that of course the focusing area 5 of the focusing optics must be inside the bathroom 10. Therefore, in choosing the correct working distance, the thickness of the transparent floor to be penetrated must also be taken into account.The value of the focusing optics is the value of the focusing optics, which is the maximum distance between the focus area 5 and the bathroom floor. The value of the focusing optics is the minimum distance between the focus area 5 and the bathroom floor. The value of the focusing optics is the lowest value, which means that the material can be solidified directly on the floor and adhered to it. This would result in the support unit 12 being impeded from exiting.at least at a minimum value of 0,25.

An example of the invention uses a high-NA lens with NA=1.4 and a working distance of 200 μm, which is designed to produce an ideal focal point when using a 170 μm thick container floor, between the exit lens and the container floor, and the lens is spaced so that the focal point is immediately above the inside of the container floor, so that the resulting voxel cannot adhere to the container floor.

The laser beam is preferably coupled to the focusing optics by a system of mirrors as shown in Figure 12.

Fig. 8 shows a device which, in its structure, essentially corresponds to the embodiment shown in Fig. 5. As an additional element, a beamforming element 15 is arranged in the form of a phase or amplitude mask in the beam passage between the rear-view mirror 2 and the focusing optics 3. By using the beamforming element 15, the laser beam is focused through the focusing optics 3 into several focuses 5a, 5b and 5c, so that material 6 to be solidified at several points can be solidified simultaneously. The number of solidification points corresponds to the number n of foci generated (parallelisation).

Other devices with parallelisation are shown in Figures 3, 4, 6 and 7, where parallelisation is achieved by using a semipermeable re-focusing mirror 16 which splits the unfocused laser beam 4 emitted from the laser source 1 into two sub-beams 17a, 17b, each directed to an independent focusing optics 3.

The devices shown in Figures 3 and 6 have two support units 12a and 12b, which are immersed in the material to be solidified 6, and which can be positioned together or independently in the Z direction. These devices can be used to produce structures of different geometry by simultaneous control of the positioning axes. Figures 4 and 7 show devices which allow simultaneous writing on a support unit 12 immersed in the material to be solidified by means of parallelisation at several points.

Other devices are shown in Figures 10 and 11. Instead of a support unit 12 which can only be positioned in a linear way, a rotary table 18 is used here, which, in addition to or as an alternative to a linear position, allows rotation around an axis of rotation 19.

In the case of the device shown in Fig. 11, a rotatable support unit 12 in a linear Z-direction positioned around a rotation axis 19 is immersed in a bath of material to be solidified. The focusing optics 3 is linearly positioned in the X and Y directions. The focus position is set so that material 6 solidifies, separates and is virtually wrapped up at the support unit 12.

List of references.

1Laser source2mirror 3focus optics4unfocused laser beam5focus 6to be fixed7under carrier8upper carrier9working distance10material container11floor12carrier unit13beam output14 housing15beam shaping element16semi-permeable mirror17a,bbeams18rotating table19rotation axis

Claims (13)

1. Device for producing three-dimensional structures of a material (6) to be consolidated, in particular from an organopolysiloxane-containing material, by locally-selective consolidation of the latter as a result of light-induced organic crosslinking, comprising:

   a laser source (1),

   a movable focusing optics (3) for the formation of one or a plurality of laser foci (5) and a material container (10) for the material to be consolidated, the laser source and the focusing optics being adapted to generate laser pulses or laser pulse sequences, respectively, which produce a two- or multi-photon polymerization of the material to be consolidated at their focal point, and wherein the focusing optics has a numerical aperture of >0.25,

   wherein the material container consists at least partially of a material which is transparent to the laser radiation used and is arranged or arrangeable in the beam path in such a way that the laser beam can be introduced into the material to be solidified through the material,

   wherein the material container remains stationary and acts as an optically defined boundary surface, and wherein a carrier unit (12) is arranged in the material container and can be positioned in relation to the latter, and

   an optical detection system for in-situ measuring of a structure already introduced into the material and/or of the carrier unit (12) acting as substrate.
2. Device according to claim 1, characterized in that the focusing optics can be moved at least in the horizontal (X-Y) plane.
3. Device according to one of the preceding claims, characterized in that the focusing optics (3) has a numerical aperture of >0.5 and preferably of >1.0.
4. Device according to one of the preceding claims, characterized in that the working distance between an objective of the focusing optics (3) and the associated laser focus is between 0.1 and 100 mm, preferably between 1 and 10 mm.
5. Device according to one of the preceding claims, characterized in that it comprises an optical system (16) for spatially dividing the laser beam (17a, 17b) and generating at least two spatially spaced laser foci (5a, 5b) or intensity maxima.
6. Device according to claim 5, characterized in that the detection system comprises a light source and an electronic detection system.
7. Device according to claim 6, characterized in that the detection system at least partially detects the topography of the carrier unit and is connected to a control system which detects surface points which possibly deviate from the desired value in such a way that these are controlled optically correctly.
8. Device according to any of the preceding claims further comprising a dispenser system for in-situ deposition of the material to be consolidated.
9. A method for producing three-dimensional structures from a material (6) to be consolidated, in particular from organopolysiloxane-containing material, by locally-selective consolidation of the same as a result of light-induced organic crosslinking due to irradiation by means of a laser (1), wherein the material to be consolidated is provided or is arranged in a material container (10), the material container is permeable to the laser employed at least in regions and is not moved during the process, using a movable focusing optical system (3) with a numerical aperture of >0.25 for positioning a laser pulse or a laser pulse sequence through the material container into the material to be consolidated onto at least one laser focus (5), so that the material container forms an optically defined interface through which the laser is introduced into the material to be consolidated, wherein the laser pulse or the laser pulse sequence triggers a two- or multi-photon polymerization of the material to be consolidated at its focal point in such a way that consolidation conditions are achieved only in the immediate vicinity of the at least one laser focus due to the intensity of the consolidation conditions therein, so that a volume element of the material to be consolidated is consolidated in the course of the duration of the laser pulse or the laser pulse sequence per focus, wherein a carrier unit (12) is positioned within the material to be consolidated relative to the at least one laser focus such that, during consolidation, the material to be consolidated adheres to the carrier unit or to material previously consolidated on the carrier unit, wherein the carrier unit can be positioned relative to the material container, and wherein a structure previously introduced into the material and/or the carrier unit acting as substrate are measured in situ using a detection system.
10. Method according to claim 9, characterized in that the focusing optics can be moved at least in the horizontal (X-Y) plane.
11. Method according to any of claims 9 and 10, characterized in that a laser beam is divided into at least two partial beams (17a, 17b) and/or at least two spatially spaced laser foci (5a, 5b) or intensity maxima are generated.
12. Method according to one of claims 9 to 11, characterized in that the material to be consolidated is supplied in situ to the material container via a dispenser system.
13. Method according to claim 9, characterized in that the carrier unit is a carrier strip which is unwound from a roll, drawn into one direction (X-direction) through the material to be consolidated in the material container and rewound after removal of the three-dimensional structure(s) produced thereon, the drawing movement taking place discontinuously or continuously.