Field of the Invention

The invention relates to the field of 2D and 3D printing of metals, specifically to printing method from nanoparticles and printing device using nanoparticles.

Background of the Invention

Currently, the 2D or 3D printing methods are a very hot topic both on a macroscopic and nanoscopic scale. On a macroscale, a 3D product can be made, for example, by machining bulk material, in particular milling where the material is removed until the final product is formed. On a nanoscale, a 3D product is prepared using, for example, lithographic techniques that involve removal of the material by etching. The material is gradually applied and selectively removed until the final product is formed. On the other hand, there are methods where the material is only added, the so-called additive manufacturing; 3D printing from thermoplastic polymers is an example on a macroscale. The advantage of these additive techniques is the easier manufacturing of objects that are only slightly filled, i.e. hollow objects. Selective laser melting (SLM) is currently the most widely used technique for metal printing. The SLM technique requires a high-power laser on the order of 1 to 10 W and typically uses a powder of microparticles of one or more materials of the size from 10 to 100 pm. A similar solution is described in document US 10,112,342. This powder of microparticles is supplied by means of a roller, and the fineness of the powder of nanoparticles limits the resolution to tens to hundreds of micrometers. Direct energy deposition (DED) is a very similar system with the supply of a powder of nanoparticles by means of a nozzle with already prepared powder of nanoparticles. However, the disadvantage is again the need for relatively large laser energy to enable printing on temperature-sensitive substrates, while the printing resolution deteriorates due to temperature fluctuations and heat transfer. Since the size of resolution for printing is dependent on the particle size of the powder of nanoparticles, it is necessary to use the smallest particles.

The logical approach is therefore to use nanopowder instead of micropowder. Scientists already explore this possibility and scientific publications have appeared in recent years, concerning the topic of nanoparticle printing on the surface of the substrate, but without the possibility of 3D printing and using nanoparticles stabilized in solutions. The disadvantage of the current layout of the device for 3D printing by means of selective laser sintering (SLS) and SLM is the dependence of printing resolution on the particle size of powders; furthermore, powders must be prepared outside the device, which prolongs the 3D printing process and the shape, size or chemical composition of the particles cannot be changed directly during printing. There is another associated disadvantage, namely the complicated application of the powder to the substrate. Another disadvantage is that nanoparticles prepared chemically in solution are very difficult to use for vacuum printing. Furthermore, the disadvantage is the complexity of combining several materials together, as well as the insufficient purity of materials prepared under atmospheric pressure due to the action of atmospheric gases.

These disadvantages have been partially overcome in document US 2010/0167958, which describes a device for trapping and reorienting dielectric nanoparticles and microparticles coated with a noble metal. This technique allows the already formed nanoparticles to be positioned and mainly to be oriented in the solution by means of a laser thanks to the localized surface plasmon resonance (LSPR), using a light source for generating a beam of light to cure the deposited nanoparticles. In principle, this technique enables the supply of nanoparticles to certain places of the substrate, however, it does not deal with joining them into a complete product, and moreover, it is carried out under atmospheric pressure, i.e. in the presence of a liquid solution and atmospheric gases.

Document drawn up by Brett B. Lewis, Robert Winkler, Xianhan Sang et. al., 3D Nanoprinting via laser-assisted electron beam induced deposition: growth kinetics, enhanced purity, and electrical resistivity, Beinlstein J. Nanocechnology, 2017, 8, 801-812, describes laser nanoprinting that works based on the chemical reaction of precursor molecules MeCpPt(IV)Me3 with an oxygen-containing reactive gas supplied to a vacuum chamber in gaseous form. A platinum structure was created at the site of electron-beam irradiation. In the case of involving laser in a process which irradiated the entire substrate, a lower resistivity of such a structure was achieved. This is thus printing from gaseous precursors using an electron beam. The disadvantage of such an approach is the need to use expensive device for generating the positioning of electron beam, but also the presence of carbonaceous coreactants in the resulting structure, and therefore the impossibility of achieving the necessary purity of the material, which can affect the conductivity and optical as well as mechanical properties. Document US 2018/0015661 describes a layout of a device for rapid printing of 3D nanostructures of polymeric material. Such a device contains two light sources, the second of which selectively reduces the energy of the first source in certain locations, thereby achieving printing output. However, the absence of the possibility of printing from metal and printing without the presence of atmospheric gases remains a disadvantage.

Document CN 112 917 893 attempted to overcome the aforementioned disadvantages by means of a device for 3D nanoprinting and 3D microprinting in an electric field. This device comprises a printing spray head, a printing nozzle, a printing base material, a flat plate electrode, a printing platform, a high-voltage power supply, a feeding module, a precise back pressure control module, and in particular an XYZ three-axis precise motion platform, and a laser range finder. However, this layout does not eliminate the disadvantage of the need for complicated transport of nanoparticles to the substrate, works under atmospheric pressure, and does not allow for the use of particles smaller than 100 nm for printing.

The object of the invention is therefore to create such a nanoparticle printing method and a nanoparticle printing device, that would integrate the preparation of powder in the form of nanoparticles, would allow for the change of parameters, i.e. material composition, size, morphology, of such nanoparticles during printing, would simply solve their transport to the substrate and their sintering within one process, and which would minimize the output power of the laser, and would work without the presence of atmospheric gases in vacuum, which would greatly facilitate the entire 3D and 2D printing process, a high purity of the final products would be achieved, and the printing resolution would be significantly increased due to the reduced size of the starting particles for printing.

Disclosure of the Invention

The object is achieved by creating a nanoprinting method, which consists in applying nanoparticles to the surface of the substrate. In this application of nanoparticles to the surface of the substrate, nanoparticles of one or more materials are prepared. These nanoparticles are supplied into a vacuum chamber, in which the nanoparticles are deposited on the substrate and cured by light radiation. It is the subject matter of the invention that the nanoparticles are prepared in a gas aggregation source, from where they are supplied into the vacuum chamber in the form of a beam directed to the surface of the substrate. The nanoparticles are exposed to the action of at least one light beam, focused on the exposure region, which is in the plane of the surface of the substrate with the nanoparticles. Furthermore, the position of the substrate relative to the light beam changes mutually using a positioning device in at least two axes in the plane intersected by the light beam, selectively sintering the nanoparticles by exposing the light beam in the exposure region to creating the printed product. Such a solution provides simple preparation of nanoparticles, as well as adjustment of their sizes during printing, addressing the task of integrating preparation of nanoparticles into the printing process without the need for complex transport of prepared nanoparticles to the substrate. Furthermore, such a solution makes it possible to work in the presence of vacuum, which greatly facilitates the entire 3D and 2D printing process; at the same time, working in a vacuum environment, specifically in a vacuum chamber, ensures high purity of the final products and significantly increases the printing resolution due to the reduced size of the starting particles for printing.

For the purposes of the description of this invention, the term “nanoparticle” refers to a cluster of atoms with a volume of 1 nm ³ to 1 pm ³ .

In a preferred embodiment, the wavelength of the light beam during exposure is adjusted to match the wavelength of increased light adsorption induced by the localized surface plasmon resonance (LSPR) in the exposure region on the surface of the substrate. The increased absorption due to LSPR enables the minimization of the output power of light beam required to sinter the nanoparticles.

In another preferred embodiment, nanoparticles are deposited while simultaneous exposure to the light beam and/or alternately with exposure of the light beam. The layout allowing for the deposition of nanoparticles while being exposed to the light beam is preferred as it allows for faster continuous printing of the resulting structures; the printing speed in the z-axis is then equal to the deposition speed of the nanoparticles in nm/s. The layout allowing for the deposition of nanoparticles alternately with the exposure of the light beam is preferred as it allows for achieving higher printing accuracy and enables the printing of objects on a larger surface area of the substrate. In the case of deposition of the layer of nanoparticles, the positioning device has enough time for the nanoparticles to be sintered even at very distant locations of the substrate. This process can then be repeated to print objects in the layer-by- layer style. In another preferred embodiment, the light beam is focused onto the exposure region by means of a focusing optical element comprising a mirror through hole, and the nanoparticles are supplied towards the substrate through this hole. This layout is preferred as it is possible to maximize the numerical aperture of the last optical element containing the aperture and thus achieve both better focusing, i.e. smaller area of the exposure region, and higher resolution in the XY axes - the plane perpendicular to the direction of deposition of nanoparticles. In addition, the higher numerical aperture enables higher localization of the exposure region in the Z axis due to the high convergence and divergence of the beam, which also increases the resolution. In addition, nanoparticles are supplied parallel to the optical axis of this focusing element, and thus they are irradiated symmetrically in the exposure region, which increases the printing resolution, and the printing is more homogeneous.

In a preferred embodiment, the light beam is a laser. Such a solution makes it possible to achieve better focusing due to spatial coherence, which increases the resolution of nanoprinting.

In another preferred embodiment, nanoparticles are prepared from at least one plasmonic material from the group: silver, gold, aluminium, copper, zirconium nitride, titanium nitride and/or their alloys, while the average volume of prepared nanoparticles is preferably up to 1 ,000,000 nm ³ . The plasmonic material provides enhanced optical absorption due to LSPR in a certain range of wavelengths, which can reduce the output power of the light beam required to sinter the nanoparticles with the same heating efficiency of nanoparticles. The selected materials achieve not only high absorbance in the form of nanoparticles but also high reflection in the form of sintered nanoparticles, i.e. bulk material. This layout is preferred due to the high absorbance of light by nanoparticles, when the attenuation of the light passing through one monolayer of nanoparticles is achieved by up to 50%, and due to the high reflectivity of the bulk material of thin metallic layers. This can result improvement in z-axis printing precision - up to one monolayer of nanoparticles.

In another preferred embodiment, nanoparticle cores are first prepared from a single material in a gas aggregation source. Another material forming nanoparticle shells is subsequently deposited on these cores in another chamber of the gas aggregation source, the melting temperature of nanoparticle shell being preferably lower than the melting temperature of nanoparticle core. This embodiment is preferred, since such nanoparticles do not sinter spontaneously. After irradiation of the metal cores of nanoparticles absorbing the energy of the light beam, spectraly tuned to the LSPR peak of nanoparticles, the temperature of the whole nanoparticles will increase, which leads to the melting of the shells of these nanoparticles, and therefore to their sintering.

The object is further achieved by a device for nanoprinting on a substrate in the manner described above. This device includes at least one vacuum chamber for placing the substrate and for depositing the nanoparticles on the substrate. The device further includes at least one light source generating a light beam for selective sintering of nanoparticles. It is the subject matter of the invention that the device further includes a gas aggregation source of nanoparticles connected into a vacuum chamber by means of an exit orifice to direct the beam of nanoparticles. The device further includes at least one focusing optical element for focusing the light beam on the exposure region lying in the plane of the substrate surface. The device further includes at least one positioning device for changing the relative position of the substrate and the light beam in the vacuum chamber. Such a device addresses the task of integrating preparation of nanoparticles into the printing process without the need for transport of prepared nanoparticles to the substrate in a mechanical way. Furthermore, the device according to the present invention makes it possible to work in the presence of vacuum, which can ensure high purity of the final products. In addition, the device significantly increases the resolution of 3D and 2D printing due to the reduced size of the starting particles for printing.

In a preferred embodiment, the entrance of the light beam is arranged inside the vacuum chamber. An optical fibre is preferably the entrance of the light beam. This arrangement is preferred as the focusing optical element with the substrate holder can be anti-vibration separated from the rest of the vacuum chamber, thereby reducing vibrations and achieving higher accuracy of nanoprinting.

In another preferred embodiment, the entrance of the light beam is arranged outside the vacuum chamber. A plane-parallel window is preferably the entrance of the light beam. This arrangement is preferred as it allows for minimizing the dimensions of the vacuum chamber, given that only the last element of the focusing optical system can be arranged inside the vacuum chamber. In a preferred embodiment, the focusing optical element comprises a concave mirror and/or a parabolic mirror and/or a flat mirror and/or an objective and/or a system of lenses. The focusing optical element is arranged inside the vacuum chamber. This arrangement is preferred as it allows for the last focusing optical element to be placed very close to the substrate and therefore can have a large numerical aperture, which allows for the light beam to be focused on a smaller area and thereby increase the accuracy of nanoprinting.

In another preferred embodiment, the focusing optical element comprises a concave mirror and/or a parabolic mirror and/or a flat mirror and/or an objective and/or a system of lenses. The focusing optical element is arranged outside the vacuum chamber and the already focused optical beam passes through a plane-parallel window into the vacuum chamber. This arrangement is preferred as it allows for minimizing the dimensions of the vacuum chamber.

In a preferred embodiment, the concave mirror and/or the parabolic mirror and/or the flat mirror has an area from 0.5 mm ² to 5 m ² and the aperture in its centre has an area from 1 pm ² to 1 m ² . Such an arrangement is preferred as nanoparticles always fall on the substrate along the optical axis at the location of the focused light beam, which makes it possible to increase the accuracy of printing, since nanoparticles in the focus are irradiated equally from all directions.

In a preferred embodiment, at least one exit orifice of the gas aggregation source has the shape of a convergent-divergent nozzle to increase the homogeneity of the nanoparticle beam and/or a Laval nozzle and/or a system of orifices with a size from 0.1 mm to 10 cm. Such a solution is preferred as it increases the homogeneity of the beam and focuses the beam so that more nanoparticles are deposited through the aperture in the concave mirror and/or the parabolic mirror and/or the flat mirror.

In another preferred embodiment, the positioning device for changing the relative position of the substrate and the light beam comprises at least one acousto-optic modulator changing the direction of the light beam and/or at least one adjustable mirror and/or at least one adjustable lens and/or adjustable optical fibre, changing the direction of the light beam and/or mechanical displacement of the substrate changing the position of the substrate relative to the position of the light beam and/or their combination. The layout of the positioning device comprising acousto-optic modulators changing the direction of the light beam and/or an adjustable optical fibre using a piezoelectric tube allows to scan with the light beam very quickly in the exposure region. While the layout of the scanning device in the exposure region based on the positioning of the substrate and/or mirrors and/or lenses allows for the simplification of the general layout of the device.

In another preferred embodiment, the gas aggregation source of nanoparticles comprises at least one magnetron and/or at least one evaporation tray and/or at least one laser ablation device, and/or a hollow cathode as a source of material for the creation of nanoparticles. Such a solution is preferred because the simple principle of magnetron sputtering and/or evaporation and/or laser ablation and/or deposition using a hollow cathode can be used to prepare nanoparticles from a wide range of materials, using a purely physical method from a solid-state material. In the case of magnetron sputtering and laser ablation, these are targets; in the case of evaporation, these are pellets, and in the case of hollow cathode, this is a tube. Such a gas aggregation source has a typical deposition rate in the order of pm/hour; however, rates that are orders of magnitude higher can also be achieved.

The advantages of the nanoprinting method and the nanoprinting device according to the present invention are mainly that the preparation of powder in the form of nanoparticles is integrated and the change of parameters, i.e. material composition, size and morphology of such nanoparticles during printing is allowed, and further their transport to the substrate and their sintering is simply solved within one process, which minimizes the output power of the laser, and works without the presence of atmospheric gases in vacuum, thus significantly facilitating the entire 3D and 2D printing process, while achieving a high purity of the final products and significantly increasing the printing resolution due to the reduced size of the starting particles for printing.

Brief Description of Drawings

The present invention will be explained in detail by means of the following figures where:

Fig. 1 shows a schematic diagram of a nanoprinting device including the entrance of a light beam inside a vacuum chamber, Fig. 2 shows a schematic diagram of a nanoprinting device including the entrance of a light beam outside a vacuum chamber,

Fig. 3 shows a schematic diagram of a nanoprinting device including a focusing optical element outside a vacuum chamber,

Fig. 4 shows a schematic diagram of a nanoprinting device involving the preparation of coreshell type nanoparticles,

Fig. 5 shows a proof of the function of plasmonic nanoprinting on nanocolumns,

Fig. 6 shows absorption spectra of Ag plasmonic nanoparticles for nanoprinting,

Fig. 7 shows the displacement of the absorption spectrum of the monolayer of nanoparticles after heating.

Preferred embodiments of the Invention

Example 1

The device 1_ for nanoprinting on the substrate 7 comprised a vacuum chamber 2 for placing the substrate 7, which was pumped by a turbomolecular pump and pre-pumped by a scroll pump. The vacuum chamber 2 was further used for the deposition of nanoparticles 4 on the substrate 7. In another non-illustrated example of the invention embodiment, the vacuum chamber 2 was pumped by a diffusion pump and pre-pumped by a rotary pump. In another non-illustrated example of the invention embodiment, a vacuum chamber 2 with a limit pressure of less than 2 Pa was used. The gas aggregation source 3 of nanoparticles 4 was installed on this vacuum chamber 2, which comprised an aggregation chamber 6 and a magnetron 21 as a source of material for the growth of nanoparticles 4. In another nonillustrated example of the invention embodiment, an evaporation tray or hollow cathode or laser ablation device was used instead of the magnetron 21 as a source of material. This gas aggregation source 3 was provided with an exit orifice 11 of the gas aggregation source 3 with a circular cross-section with a diameter of 3±2 mm ² . In another non-illustrated example of the invention embodiment, the exit orifice 11 of the gas aggregation source 3 comprised 5 orifices with a size from 0.1 mm to 10 cm mounted behind each other, making the beam of nanoparticles 4 narrower, or an adjustable iris diaphragm with a variable area up to 100 cm ² was used, or a convergent-divergent nozzle was used. This convergent-divergent nozzle directed the beam of nanoparticles 4 on the one hand, and on the other hand increased their amount deposited on the substrate 7 due to the limitation of turbulent gas flow. The device 1_ was further provided with one light source 5 generating a light beam 9 for selective sintering of nanoparticles 4. In another non-illustrated example of the invention embodiment, two and/or more light sources 5 generating light beams 9 were used. This light beam 9 was focused on the exposure region 20 lying in the plane of the surface of the substrate 7 by means of a focusing optical element 8. The focusing optical element 8 for the light beam 9 comprised a parabolic mirror 13 with a size of 20 cm ² with a hole 15 in its centre with an area of 9 mm ² , through which a beam of nanoparticles 4 was deposited. The light beam 9 was guided to this focusing optical element 8 by means of a collimator, so that the substrate 7 with nanoparticles 4 was in the focus of the light beam 9 after its reflection from the focusing optical element 8,

1.e. parabolic mirror 13. In another non-illustrated example of the invention embodiment, the parabolic mirror 13 had a size from 0.5 mm ² to 5 m ² with a hole 15 with an area from 1 pm ² to 1 m ² . In another non-illustrated example of the invention embodiment, a plane mirror 14 was used to which the convergent beam was directed, or a plane mirror 14 was used that was located completely outside the beam of nanoparticles 4, or an objective was used that was located completely outside the beam of nanoparticles 4 and/or a parabolic mirror 13 was used. Nanoparticles 4 made of silver were created in a gas aggregation source 3 so that the pressure was set to 50 Pa and the current in the magnetron 21 was set to 0.4 A. In another nonillustrated example of the invention embodiment, the pressure was varied from 1 to 1000 Pa and the output power of the magnetron 21 in the range from 1 to 1000 W, with the optimal conditions selected according to the condition of the sputtering target. A laser was chosen as the light beam 9, the light beam input 10 of which was arranged inside the vacuum chamber

2. An optical fibre was used as the light beam input 10. The wavelength of the light beam 9 was chosen to match the plasmonic peak of the nanoparticles 4 in the range from 345 nm to 455 nm, specifically, lasers at wavelengths of 355 nm and 375 nm were used. In another nonillustrated example of the invention embodiment, light generated by means of a xenon lamp after passing through a monochromator with a selected wavelength of 360 nm was used instead of a laser. In another non-illustrated example of the invention embodiment, the light beam input 10 was placed outside the vacuum chamber 2, and a plane-parallel window was used as the light beam input 10. In another non-illustrated example of the invention embodiment, the material of nanoparticles 4 was selected from the group of silver, gold, aluminium, copper, zirconium nitride, titanium nitride, or their alloys, to the plasmonic peak of which the wavelength of the laser beam was tuned. The device 1_ further included a positioning device 12 for changing the relative position of the substrate 7 and the light beam 9 in the vacuum chamber 2. This positioning device 12 comprised a table used to mechanically move the substrate 7 in the XYZ axis, changing the position of the substrate 7 relative to the fixed position of the focus of the light beam 9 in the form of a laser beam. In another non-illustrated example of the invention embodiment, the positioning was made using at least one acoustooptic modulator 16 changing the direction of the light beam 9, and/or the direction of the light beam 9 was changed by adjustable mirrors 17, and/or the direction of the light beam 9 was changed using adjustable lenses. Then, a 3D printed product with a height of 500 nm was created by simultaneously depositing nanoparticles 4 and exposing them to the light beam 9 for 30 minutes. Subsequently, solid nanoparticles 4 were removed by immersion of the substrate 7 in a solution of surfactant, specifically sodium dodecyl sulfate, for 10 minutes while shaking at 100 rpm. In another non-illustrated example of the invention embodiment, a 3D printed product was created by applying nanoparticles 4 to an exposure region 20 alternately with exposure to a light beam 9.

Example 2

The device 1. comprised a vacuum chamber 2, which was equipped with one gas aggregation source 3, see Figure 1. This gas aggregation source 3 included a 3-inch magnetron 21 intended for deposition of thin films, which was used to generate the material. The magnetron 21 was inserted into a cylindrical aggregation chamber 6 with a diameter of 10 cm and a length of 30 cm, which was terminated with an exit orifice 11 of the gas aggregation source 3. In another non-illustrated example of the invention embodiment, a 2-inch magnetron 21 was used and the aggregation chamber 6 was 16 cm in diameter, or a 1-inch magnetron 21 was used and the aggregation chamber 6 was 4 cm in diameter. Quartz microbalances were installed in the vacuum chamber 2 in the direction of the light beam 9. First, an inert gas was introduced into the vacuum chamber 2 and the optimum of deposition conditions was found. The optimum varied depending on the state of the silver sputtering target and had to be found again after a certain period of time. In another non-illustrated example of the invention embodiment, the pressure was varied from 10 to 200 Pa, the magnetron current from 0.01 A to 1 A, and the distance of the magnetron 21 from the exit orifice 11 of the gas aggregation source 3 was in the range from 0 to 30 cm. The optimum sought was found at a pressure of 40 Pa and a current of 0.2 A and the distance of the magnetron 21 from the exit orifice 11 of the gas aggregation source 3 was equal to 5 cm. Nanoparticles 4 with a volume of 1 ,000 nm ³ were produced in this way. In another non-illustrated example of the invention embodiment, nanoparticles 4 with a volume from 1 nm ³ to 1 ,000,000 nm ³ were produced. These nanoparticles 4 were deposited through the 3 mm hole 15 of the parabolic mirror 13 with a diameter of 20 cm on the substrate 7. In another non-illustrated example of the invention embodiment, the diameter of the parabolic mirror 13 was 5.08 cm. In another non-illustrated example of the invention embodiment, the size of the hole 15 was 2.54 cm, while the parabolic mirror 13 had a diameter of 10.6 cm. The presence of nanoparticles 4 was demonstrated using LIV-VIS spectrophotometry. A comparison of the spectra of optimized and non-optimized nanoparticles 4 can be seen in Figure 6, where in the case of non-optimized nanoparticles 4, increased absorption was detected in the region from 345 to 455 nm, mostly at the wavelength of 380 nm. In the case of optimized nanoparticles 4, increased absorption was detected in the region from 300 to 800 nm, mostly at the wavelength of 410 nm. Figure 7 shows that the LSPR peak was shifted from 360 nm to 492 nm after heating and sintering of nanoparticles 4, whereby the material stopped absorbing at the laser wavelength and thus the material was not further heated significantly. The substrate 7 was installed in the vacuum chamber 2, which was positioned using mechanical displacement in the XYZ axis, thereby achieving the exposure of different locations of the substrate 7 to a laser beam at a wavelength of 355 nm. The deposited nanoparticles 4 were thus sintered in different locations by means of gradual deposition.

Example 3

A diamond-shaped structure was generated by means of a nanoprinting device according to Example 2. After the structure was printed by sintering of nanoparticles 4, solid nanoparticles 4 were removed from the sample by means of surfactant in ultrasound and then by means of prolonged exposure of surfactant with constant stirring at 100 rpm. The resulting structure was further analysed using optical microscopy. When the sample was measured in terms of transmission, the areas with sintered nanoparticles 4 were dark, corresponding to no light passing through these areas. On the contrary, in reflection, light reflected from the same areas. Sintered nanoparticles 4 created a facet, i.e. , mirror, which did not transmit but reflected the light. Example 4

Structures with a square layout composed of 100 columns in a 10x10 grid were printed by alternating deposition and exposure by means of the nanoprinting device prepared according to Example 2 using a laser with a wavelength of 355 nm, see Figure 5. The output power of the light beam 9 in the form of the laser beam for Ag nanoparticles 4 was optimized. In the case of optimal output power, black points were obtained in the transmission at the location of the columns and white points were obtained in the reflection, which proves that the columns were not created by nanoparticles 4 but sintered bulk silver. For the negative control, the output power of the laser was tripled. As a result, there were bright dots in the transmission and dark dots in the reflection in laser-irradiated areas, indicating that the material in the laser-irradiated areas has been ablated and the structure was not printed.

Example 5

The device was prepared according to Example 2, while another aggregation chamber 6 in the shape of a 6-way cross with a diameter of flanges of 10 cm was inserted between the gas aggregation source 3 and the vacuum chamber 2 with a volume of 0.05 m ² , see Figure 4. The gas aggregation source 3 had a diameter of 10 cm and contained an inserted planar magnetron 21 with an area of 45 cm ² with an installed Ag target and a 4 mm exit orifice 11 of the gas aggregation source 3. The planar magnetron 21 with the installed Ag target was used to prepare the cores 18 of nanoparticles 4 with a volume of 1 ,000 nm ³ . The inserted aggregation chamber 6 was equipped with the second magnetron 21 with an Al target of the same area and an exit orifice 11 of the gas aggregation source 3 with a diameter of 8 mm. The second magnetron 21 with the installed Al target was used to prepare the shells 19 of nanoparticles 4 with a volume of 1 ,500 nm ³ . In another non-illustrated example of the invention embodiment, the total volume of nanoparticles was up to 1 ,000,000 nm ³ . The second exit orifice 11 of the gas aggregation source 3 slowed down the flow of the beam of nanoparticles 4, while the magnetron 21 covered the cores 18 of the nanoparticles 4 created in the first aggregation chamber 6. This made it possible to prepare core-shell type nanoparticles 4, with the core 18 of nanoparticles 4 having a higher melting temperature than the shell 19 of nanoparticles 4. Thanks to the light beam 9 in the form of a laser beam, which was collimated by the focusing optical element 8 and entered the vacuum chamber 2 through light beam input 10 in the form of plane-parallel window; it was further moved relative to the substrate 7 by means of adjustable mirrors 17, which then made it possible to sinter nanoparticles 4 when the cores 18 of nanoparticles 4 remained unchanged and only the shells 19 of nanoparticles 4 were sintered. Thus, the structure was printed using simultaneous deposition. In addition, the positioning device 12 was used in the form of an XYZ table, which made it possible to print on a larger area.

Example 6

First, the vacuum chamber 2 of the device 1_ prepared according to Example 1 was prepared. The gas aggregation source 3 comprised the aggregation chamber 6 with a diameter of 16 cm equipped with two planar magnetrons 21 with an area of 20 cm ² producing nanoparticles 4 composed of the TiN core 18 of nanoparticles 4 wrapped in the SiC>2 shell 19 of nanoparticles 4. Nanoparticles 4 thus prepared had a volume of 2,000 nm ³ . In another non-illustrated example of the invention embodiment, the volume of nanoparticles 4 thus prepared was up to 1 ,000,000 nm ³ . In another non-illustrated example of the invention embodiment, nanoparticles 4 containing elements from the group: silver, gold, aluminium, copper, zirconium, titanium, or their alloys were produced. In another non-illustrated example of the invention embodiment, the aggregation chamber 6 was tapered with a horizontal cross-section in the range from 50 cm to 1 mm. An inert cooling gas and nitrogen were introduced into the aggregation chamber 6 for the possible creation of nitrides with plasmonic properties showing localized surface plasmon resonance, in particular TiN and ZrN. The aggregation chamber 6 was terminated with a fully adjustable iris exit orifice 11 of the gas aggregation source 3 with a variable radius of up to 100 cm. In this configuration, it was possible to prepare either nanoparticles 4 of metals installed on magnetrons 21 or their alloys. Light beams 9 in the form of laser beams corresponding to the plasmonic peaks of nanoparticles 4 were then introduced into the vacuum chamber 2. Nanoparticle layers of various materials could be sintered in one deposition using alternating deposition and exposure by switching on different magnetrons 21 and laser beams.

Example 7

Two gas aggregation sources 3 with magnetrons 21 creating silver and copper nanoparticles 4 prepared according to Example 2 were installed on the vacuum chamber 2 of the device 1_ prepared according to Example 1. Two light sources 5 were introduced into the vacuum chamber 2 according to Example 1. One light source 5 was tuned to the plasmonic peak of silver nanoparticles 4 and the other light source 5 was tuned to the plasmonic peak of copper nanoparticles 4. Both light sources 5, working at wavelengths of 375 nm and 650 nm, were independently positioned on the substrate 7 by means of the positioning device 12 in the form of four adjustable mirrors 17 located outside the beam of nanoparticles 4. In another nonillustrated example of the invention embodiment, acoustic-optic modulators 16 or a piezoelectric tube were used instead of adjustable mirrors 17, changing the position of the optical fibre relative to other elements of the optical system and thus the exposure area. In this way, multi-material structures were created using laser sintering by both simultaneous and alternating deposition.

Example 8

The gas aggregation source 3 prepared according to Example 2 was installed on the vacuum chamber 2 of the device 1. prepared according to Example 1. This gas aggregation source 3 was terminated with a convergent-divergent nozzle with a diameter of 4 mm to homogenize and focus the beam of nanoparticles 4 of silver so as to focus the beam into a hole 15 in the parabolic mirror 13 with a diameter of 2 to 5 mm. In another non-illustrated example of the invention embodiment, a Laval nozzle with a diameter of 4 mm or a system of coaxial orifices 11 of the gas aggregation source 3 with diameters from 0.1 mm to 10 cm was used.

Example 9

The gas aggregation source 3 prepared according to Example 2 and based on the planar magnetron 21 with a diameter of 7.62 cm was installed within the vacuum chamber 2 of the device prepared according to Example 1. In another non-illustrated example of the invention embodiment, the laser ablation device as a source of material or an evaporation tray or a hollow cathode was installed in the gas aggregation source 3 instead of the magnetron 21. The gas aggregation source 3 was terminated with a rectangular exit orifice 11 of the gas aggregation source 3 with a size of 1 mmx10 mm, which was directly connected to the parabolic mirror 13 with the hole 15 of the same size as the exit orifice 11 of the gas aggregation source 3. In another non-illustrated example of the invention embodiment, a plane mirror 14 was used. The light beam 9 in the form of a laser beam was moved by means of an adjustable mirror 17 with piezoelectric displacement in one axis, while the substrate 7 was moved mechanically in the second axis. Example 10

The gas aggregation source 3 prepared according to Example 2 was installed within the vacuum chamber 2 of the device prepared according to Example 1 , see Figure 3. In another non-illustrated example of the invention embodiment, the aggregation chamber 6 was based on the cylindrical magnetron 21 with a target area of 100 cm ² . Instead of scanning with substrate 7, scanning with laser beam was used, which was performed by means of acoustooptic modulators 16. In another non-illustrated example of the invention embodiment, adjustable mirrors 17 were used. This light beam 9 was then collimated by means of a focusing optical element 8 in the form of a system of lenses arranged outside the vacuum chamber 2. In another non-illustrated example of the invention embodiment, the beam was collimated by means of a concave mirror with the hole 15 for the beam of nanoparticles 4. In another nonillustrated example of the invention embodiment, the light beam 9 was collimated by a system of lenses and then fell on the plane mirror 14 with a diameter of 2.54 cm with the hole 15 with a diameter of 5 mm. In another non-illustrated example of the invention embodiment, the focusing optical element 8 in the form of the system of lenses was arranged inside the vacuum chamber 2. In another non-illustrated example of the invention embodiment, the light beam 9 was collimated by means of a focusing optical element 8 in the form of an objective, outside the vacuum chamber 2. In another non-illustrated example of the invention embodiment, the focusing optical element 8 in the form of the objective was arranged inside the vacuum chamber 2. In another non-illustrated example of the invention embodiment, the parabolic mirror 13 had a diameter of 5.08 cm and a hole 15 with a size of 5 mm. In another nonillustrated example of the invention embodiment, the parabolic mirror 13 had an area from 0.5 mm ² to 5 m ² and the hole 15 had an area from 1 pm ² to 1 m ² .

Example 11

The vacuum chamber 2 of the device prepared according to Example 1 with the gas aggregation source 3 prepared according to Example 2 was equipped with a plane-parallel window with a diameter of 5.08 cm for the passage of the light beam 9 in the form of a laser beam, see Figure 2. The laser beam was first guided by an optical fibre and then expanded by means of a collimator and guided through free space perpendicular to a plane-parallel window, through which it passed and fell on the parabolic mirror 13 with a diameter of 5.08 cm inside the vacuum chamber 2, thereby focusing it on the exposure region 20 of the substrate 7 on which titanium nanoparticles 4 were deposited in one monolayer. After the nanoparticles 4 were exposed, another monolayer of titanium nanoparticles 4 was deposited. This process was repeated until the entire titanium product was created by this alternating deposition.

Industrial Applicability

The nanoprinting method and the nanoprinting device according to the present invention can be particularly used for prototyping and manufacturing of metal objects on a scale between lithographic techniques and SLM printing techniques using micropowders.

List of Related Marks

1 device

2 vacuum chamber

3 gas aggregation source

4 nanoparticles

5 light source

6 aggregation chamber

7 substrate

8 focusing optical element

9 light beam

10 light beam input

11 exit orifice of the gas aggregation source

12 positioning device

13 parabolic mirror

14 plane mirror

15 hole

16 acoustic-optic modulator

17 adjustable mirror

18 core of nanoparticle

19 shell of nanoparticle

20 exposure region

21 magnetron