EP4192378A1

EP4192378A1 - Digitally controlled application of a cryogenic liquid drop by drop

Info

Publication number: EP4192378A1
Application number: EP21773742.8A
Authority: EP
Inventors: Andreas GIMMER
Original assignee: Wuerth Elektronik GmbH and Co KG
Current assignee: Wuerth Elektronik GmbH and Co KG
Priority date: 2020-09-08
Filing date: 2021-09-08
Publication date: 2023-06-14
Also published as: DE102020123415A1; DE102020123415B4; WO2022053471A1; WO2022053471A9; CN116601420A

Abstract

The invention relates to a use of a cryogenic liquid (103). The use comprises digitally controlled application of the cryogenic liquid (103) drop by drop onto a surface (112, 712) for targeted influencing of a temperature of the surface (112, 712) and/or of a region located below the surface, in particular a layer or a substrate.

Description

Digitally controlled dropwise application of a cryogenic liquid

Description

The invention relates to a use of a cryogenic liquid, a device which is designed for a corresponding use of a cryogenic liquid, and a system for producing a component, which includes a corresponding device.

The application of cryogenic liquids to various surfaces for various purposes is known from the prior art. However, conventional methods often only allow a rough control of the application process, which does not meet many requirements. The object on which the invention is based is achieved in each case with the features of the independent patent claims. Embodiments of the invention are specified in the dependent claims. Embodiments of the invention can be combined with one another provided they are not mutually exclusive.

In one aspect, the invention relates to the use of a cryogenic liquid, characterized in that the cryogenic liquid is applied to a surface drop by drop in a digitally controlled manner in order to influence, in particular to specifically influence, a temperature of the surface.

According to embodiments, the use also includes, for example, influencing, in particular targeted influencing, of a temperature of an area lying beneath the surface, in particular of a layer or a substrate.

Embodiments can have the advantage that they enable a targeted local thermo-kinetic influencing of the surface to which the cryogenic liquid is applied dropwise in a digitally controlled manner. For example, the application of the cryogenic liquid droplets can serve to specifically, for example exclusively, specifically influence the temperature of the surface acted upon, for example a surface of a substrate. A temperature of the surface can be set by means of this targeted temperature influencing. For example, a two-dimensional spatial temperature gradient can be generated in a targeted manner. In addition, the application can serve, for example, to selectively influence the temperature of an area below the applied surface, i.e. a three-dimensional area of an object whose surface is exposed to the cryogenic liquid. A temperature of the area can be set by means of this targeted temperature influencing. For example, a three-dimensional spatial temperature gradient can be generated in a targeted manner. “Application” or “acting on” is understood here to mean such a dropwise, digitally controlled application of the cryogenic liquid that the applied droplets of the cryogenic liquid influence the temperature of the “acted on” surface.

It is irrelevant whether the cryogenic liquid reaches the surface, remains on it or changes to a gaseous state of aggregation during or immediately after the application process and leaves the surface again. With other pn Wnrtpn there can«; Aiifhrinppn hzw Rpaii chlappn pinp Annlikation dpr Tronfchpn flow of the surface through the cryogenic liquid. Furthermore, the “application” or “acting on” can include an application of the droplets, in which the applied droplets of the cryogenic liquid change into the gaseous state of aggregation during the application process. As a result of the transition to the gaseous state of aggregation, the cryogenic liquid according to embodiments, for example, does not reach the "acted on" surface. The transition to the gaseous state of aggregation creates, for example, a temperature sink over the "acted on" surface, which extracts heat from the "acted on" surface Heat is withdrawn, for example, via the atmosphere the surface is in. Thus, for example, the temperature of the surface can be indirectly influenced by the cryogenic liquid.

Whether the droplets reach the surface or not can be done, for example, by controlling or regulating one or more of the following parameters: droplet size, exit velocity, distance of the printhead from the surface, angle of droplet emission relative to the surface, ambient pressure and/or ambient temperature.

It can thus be specifically controlled, for example, whether, when and/or where the droplets reach the surface. This corresponds to focusing the cooling using the cryogenic liquid. When the cryogenic liquid reaches the surface, locally stronger cooling of the surface and/or cooling that extends deeper into the area below the surface can be achieved. If the cryogenic liquid does not reach the surface, a weaker cooling of the surface locally and/or a cooling that extends less deeply into the area below the surface can be achieved. In addition, excessive stress on the surface due to direct contact of the surface with the cryogenic liquid can be avoided. Furthermore, undesired, for example chemical interactions of the cryogenic liquid with the surface and/or with substances applied to the cooled surface can be avoided.

According to one embodiment, the temperature of the surface is recorded with a suitable, preferably non-contact, temperature measuring device during the application of the cryogenic liquid. For example, an infrared thermometer can be used. The temperature can be measured once or preferably several times, in particular continuously, during dpr Rpaii chlaPiin? ppmpwpn wprdpn 7 R 11m fp<;t7iistpllpn. oh dip Tpmnpratur in A distribution scheme for distributing the cryogenic liquid on and/or over the surface can define, for example, where, when, how much cryogenic liquid is to be applied and whether the applied cryogenic liquid is to reach the surface or not. For example, the distribution scheme defines a spatial and/or temporal distribution of the cryogenic liquid. For example, the distribution scheme defines a spatially and/or temporally varying release quantity of the cryogenic liquid. For example, the distribution scheme may define a distribution in which the delivery of the cryogenic liquid is modulated such that the cryogenic liquid reaches the surface at one or more locations while not reaching the surface at one or more other locations. Thus, for example, a distribution can be implemented which includes both a direct and an indirect temperature influence on the surface in a locally controlled manner.

This thermo-kinetic influencing of the surface can be used, for example, to prepare the exposed surface, i.e. to set the temperature, for a subsequent processing operation on the surface. For example, the thermo-kinetic influencing of the surface can serve to functionally influence the surface acted upon. The temperature setting can affect the physical, chemical and/or biological properties of the surface. For example, the thermo-kinetic influencing of the surface can serve to structurally influence the surface that is acted upon.

Embodiments can have the advantage that a cryogenic liquid is applied to the surface precisely drop by drop, ie drop by drop. This enables a finely structured temperature control or cooling control on the corresponding surface. For example, the droplets can be small droplets. For example, it can be a droplet size of less than 100 picoliters (pl), preferably less than 10 pl. For example, they can be droplets with a droplet size of 1 pl to 10 pl, preferably 1 pl to 5 pl. A corresponding finely structured temperature control or temperature regulation on the surface makes it possible to control physical and/or chemical processes or reactions on the surface precisely or with pinpoint accuracy. Furthermore, by regulating the locally applied amount of cryogenic liquid, for example, the corresponding cooling effect can be controlled not only two-dimensionally but also three-dimensionally. and chemical nature of the surface. If more cryogenic liquid is applied locally, its cooling effect can last longer, for example, since a larger cold reservoir is provided. In addition, by repeating or continuously continuing the application of the cryogenic liquid, the temperature profile over time on the surface and in the interior of the object to which the action is applied, for example a substrate, can be controlled or regulated in conjunction with a suitable temperature measurement. Based on the temperature measurement, for example, the amount of cryogenic liquid dispensed, such as the number and/or frequency of the droplets, can be regulated. For example, the delivery of the cryogenic liquid can be regulated to reach and/or maintain a predefined temperature.

Preferably non-contact temperature measurement.

In applying the cryogenic liquid to the surface, a print head used for the application may be in contact with the surface or spaced from it.

According to embodiments, the digitally controlled deposition of the cryogenic liquid controls a location of the deposition in 2D or 3D, a volume of the deposition, and/or an angle of the deposition relative to the surface. For example, the volume and/or the angle can be position-dependent.

Embodiments can have the advantage that the application of the cryogenic liquid can be controlled as a function of position. Here, the position of one or more print heads and/or one or more print nozzles of a print head can be detected and controlled relative to the surface. For example, the dropwise deposition is dependent on a position in 2D, ie dependent on a position within a plane parallel to the surface. For example, the dropletwise application occurs as a function of a 3D position, ie as a function of a position in three dimensions above the surface. For example, the surface can include structures and the print head can be moved in the z direction perpendicular to the surface in addition to movements in the x and y directions parallel to the surface. The x, y and z directions are, for example, coordinates of a Cartesian coordinate system. particularly into the object having the surface. The volume of cryogenic liquid applied can be controlled, for example, by controlling the number and/or size of cryogenic liquid droplets applied at the same location.

Angular control of the dropwise application of the cryogenic liquid relative ZL of the surface makes it possible, for example in the case of a structured surface, to cover corresponding structural elements of the surface with cryogenic liquid with pinpoint accuracy. For example, in the case of elevations and/or indentations, side walls of the corresponding elevations and/or indentations in the surface can also be covered with cryogenic liquid in precise droplets. For example, it is possible to selectively cover corresponding side surfaces.

A digital controller is understood to mean a computer-based controller using control commands which, for example, controls the application of the cryogenic liquid in droplets as a function of the position. In particular, the dispensing position of the cryogenic liquid in 2D or 3D as well as the volume, i.e. the number of droplets and/or droplet size, and the angle of the droplet dispensing can be controlled. For example, a rate at which the droplets are dispensed can also be controlled.

Digital control of the drop-by-drop delivery of the cryogenic liquid can have the advantage that the amount of cryogenic liquid delivered can be precisely controlled, on a drop-by-drop basis, i.e., in the picoliter range for example. In the case of digital control, control is accomplished using digital control commands. Corresponding control commands translate, for example, a predefined distribution scheme for distributing the cryogenic liquid on and/or over the surface into instructions for controlling a pressure unit applying the cryogenic liquid to the surface.

According to embodiments, the cryogenic liquid is stored in a container that is fluidly connected to a digital printhead. The digital print head is digitally controlled to apply the cryogenic liquid drop by drop to the surface. spatially and/or temporally varying release quantity of the cryogenic liquid. For example, the distribution scheme may define a distribution in which the delivery of the cryogenic liquid is modulated such that the cryogenic liquid reaches the surface at one or more locations while not reaching the surface at one or more other locations. Thus, for example, a distribution can be implemented which includes both a direct and an indirect temperature influence on the surface in a locally controlled manner.

Embodiments can have the advantage that, for example, a printing unit can be provided with a digital print head, which is digitally controlled and, depending on the control, dispenses the cryogenic liquid dropwise over the surface and/or applies it to the surface.

According to embodiments, the digital printhead is moveable relative to the surface.

Embodiments can have the advantage that, by moving the digital print head in 2D or 3D, different dispensing positions can be assumed relative to the surface and the cryogenic liquid can be dispensed or applied to the surface depending on the respective dispensing position. According to alternative embodiments, an object comprising the surface can be movable in 2D and/or 3D relative to the print head. For example, both the print head and the object can be movable. For example, a detection unit is also provided, which detects the relative position of the surface and the digital print head to one another. For this purpose, for example, the object and/or the digital print head can have position markings, which are detected by the corresponding detection unit. The corresponding acquisition unit can, for example, comprise an image sensor for acquiring image data. For example, the corresponding detection unit can be configured for a distance measurement using interferometry, in particular laser interferometry.

For example, the position of the digital print head can be controlled so that it maintains a predefined minimum distance from the surface. For example, the position of the digital printhead can be controlled to maintain a constant distance from the surface and/or a distance within a predefined interval.

Rpj nipkwp p can dip position dps dieitalpn Driickkonfs so ppstpuprt wprdpn that dr According to embodiments, the surface has a temperature above -50°C, above -20°C, in particular above 0°C, before the liquid is applied. According to embodiments, the surface is at room temperature before the liquid is applied. According to embodiments, the surface has the body temperature of an animal or a human before the liquid is applied.

According to embodiments, the surface has a maximum temperature of 100° C. before the liquid is applied.

Embodiments can have the advantage that strong local cooling of the surface can be achieved by means of the cryogenic liquid. For example, the temperature of the cryogenic liquid can be -275 to -75°C. For example, the cryogenic liquid may be -272°C to -269°C in the case of helium, -259°C to 252°C in the case of hydrogen, -210 to -196°C in the case of nitrogen, 189 to 189°C in the case of argon -186°C, in the case of oxygen -218°C to -183°C and in the case of carbon dioxide -78.5°C.

The corresponding temperature ranges can be varied by adjusting the pressure. For example, at a lower pressure, lower temperatures can be achieved with the cryogenic liquid without a liquid-to-solid phase transition. For example, at higher pressure, higher temperatures can be achieved with the cryogenic liquid without a liquid to gas phase transition.

According to embodiments, the cryogenic liquid is applied under a protective atmosphere. According to embodiments, the cryogenic liquid is applied under a protective atmosphere with an increased or reduced oxygen content relative to the normal atmosphere. For example, the use of a protective atmosphere serves to prevent chemical reactions between the surface exposed to the cryogenic liquid and the atmosphere, i.e. the protective atmosphere.

Embodiments can have the advantage that undesired chemical reactions of the cryogenic liquid and/or chemical components of the surface can be suppressed by using a protective atmosphere. For example, protective gases such as nitrogen, carbon dioxide, oxygen, argon, helium, hydrogen and/or carbon monoxide can be used for the protective atmosphere. the

Gphalt dpr pnt<;nrpchpndpn c.hiit7Pasp in dpr Atmo<;nh rp can rplativ 7iir Normalat- For example, an oxygen-free atmosphere can be used, such as in the case of using hydrogen as the cryogenic liquid. On the other hand, for example, the oxygen content in the protective atmosphere can be increased relative to the normal atmosphere. This can be particularly advantageous if the cryogenic liquid is used in connection with an oxidation process. In this case, for example, no hydrogen is used as the cryogenic liquid.

According to embodiments, the cryogenic liquid is applied under overpressure. According to embodiments, the cryogenic liquid is applied under reduced pressure.

Embodiments can have the advantage that by controlling the pressure under which the cryogenic liquid is applied, the temperature of the applied cryogenic liquid can be controlled. This means that the physical state of the cryogenic liquid in the liquid phase is dependent on the pressure. By changing the pressure, the temperature at which the cryogenic liquid is actually in the liquid state can be controlled. The temperature which the cryogenic liquid has when it is applied as a liquid can thus also be varied. For example, the pressure can be reduced and as a result lower temperatures can be achieved with the cryogenic liquid without it changing into the solid phase. For example, the pressure can be increased and as a result higher temperatures can be achieved with the cryogenic liquid without it changing into the gas phase. Furthermore, by controlling the pressure of the atmosphere in which the cryogenic liquid is applied to the surface, it can be controlled whether the applied cryogenic liquid remains in the liquid phase or changes to a gaseous or solid phase. Thus, for example, contact times between the cryogenic liquid and the surface can be controlled. On the one hand, this makes it possible to control the effect of the filling effect and, on the other hand, interactions of the cryogenic liquid with other physical and/or chemical processes for which the cooling takes place can be controlled and/or prevented. For example, the pressure can be reduced, thereby achieving a transition of the cryogenic liquid from the liquid to the gaseous phase. Thus, the cryogenic liquid can be detached from the surface again within a short time and a disturbance of further subsequent physical and/or chemical processes can be avoided. • Capturing a 2D and/or 3D structure of the surface and/or an object that includes the surface,

• determining structural elements of the surface to which the cryogenic liquid is to be applied, depending on the detected 2D and/or 3D structure; and

• generating control data designed to control the application of the cryogenic liquid to the designated features.

Embodiments can have the advantage that a 2D and/or 3D structure of the surface or of the object comprising the surface is recorded. A corresponding detection can, for example, take place visually using a camera. For example, the detection can take place using a microscope. In particular, for example, a scanning probe microscope such as a scanning tunneling microscope, atomic force microscope, magnetic force microscope, scanning near-field optical microscope or a scanning near-field acoustic microscope can be used. For example, a digital model, for example a 3D model, of the surface is created using the recorded data. Based on the recorded 2D and/or 3D surface structures, structural elements of the surface to which the cryogenic liquid is to be applied can be determined. A corresponding determination of the structure elements can take place, for example, by a selection by a user or automatically using an image recognition method. For example, the structural elements of the surface are determined and/or the control data are generated automatically. For example, the control data is generated automatically as a function of the structural elements of the surface determined, for example, by means of an image recognition method.

For example, it can be specified for a specific application which characteristic properties have structural elements to which cryogenic liquid is to be applied. Corresponding properties can be, for example, geometric properties or physical properties, such as color in the case of an image acquisition of the surface structure. Color here refers to the reflectance behavior when irradiated with light of one or more wavelengths in the visible and/or non-visible wavelength range, ie monochromatic or polychromatic light. Depending on the specific structural elements, control data can be generated which control the application of the cryogenic liquid to the specific structural elements. The corresponding control data can define, for example, at which positionpn WPICHP Vnlumpn krvoppnpr Flii<;<;ipkpit in wplcnpm Winkpl ar>7iipphpn h?w aiif7iihrin- According to embodiments, the use also includes creating a digital distribution scheme for applying the cryogenic liquid to the specific structural elements depending on the detected 2D and/or 3D structure. The control data is configured to control the application of the cryogenic liquid to the particular structural elements according to the distribution scheme.

For example, a digital distribution scheme is created that defines the application of the cryogenic liquid to the specific structural elements depending on the detected 2D and/or 3D structure. A 3D model of the structures of the surface is used for this purpose, for example. A corresponding distribution scheme can be used in particular to visualize a proposal for applying the cryogenic liquid. A corresponding suggestion is generated automatically, for example, and/or using user input. For example, the recorded 2D and/or 3D structure or a digital model of the surface generated using the recorded data can be used to define at which positions and at what angles cryogenic liquid is to be applied. Furthermore, it can be defined on the basis of 3D structures, for example, which volume of cryogenic liquid is to be applied. For example, if a survey is to be completely cooled, it may be necessary to apply a larger amount of cryogenic liquid, ie a larger volume, locally to the corresponding survey than in the case of a planar structure in which no cooling effect in depth, ie perpendicular to the Surface in the corresponding object is necessary. For example, the control data is designed to control the application of the cryogenic liquid to the specific structural elements according to the distribution scheme. In other words, the control data can be a translation of the distribution scheme into control data, i.e. control commands, for a controller controlling the application of the cryogenic liquid.

According to embodiments, the digital distribution scheme is displayed on a display device and controlling the application of the cryogenic liquid using the control data according to the distribution scheme entails receiving confirmation of the displayed distribution scheme via an input device.

Embodiments can have the advantage that the digital distribution scheme is displayed on the display device and is thus visualized for a user. The user can there"; pnt nrpchpndp Vprtpihinp<;<;chpma nrüfpn Rpj nipkwpi p will be there«; pnt nrpchpndp Vpr Change droplet size, number of droplets and/or droplet rate. Furthermore, for example, angles can be set at which the cryogenic liquid is applied. For example, use of the control data according to the distribution scheme requires explicit confirmation of the displayed distribution scheme by the user. A corresponding confirmation can be received from the user directly in response to the display of the distribution scheme or after receiving correction information and changing the distribution scheme according to the received correction data.

According to embodiments, the surface is living or dead biological material. The biological material includes in particular: microorganisms, a cell culture and/or a cell assembly, in particular an in-vivo or in-vitro cell assembly, in particular an in-vitro cell assembly for the growth of an artificial organ or part of an organ, the biological material being human or animal skin or tissue sample.

Due to the very rapid cooling of cells, ice crystals form inside and on the surface of cells, which perforate the cell membrane. This leads to the penetration of water into the cell, the collapse of vital regulatory processes and rapid cell death. Freezing speed has been shown to have a strong impact on the proportion of cells that die due to freezing. Embodiments may have the advantage of having a cooling rate ("freezing rate") of over 100°C per minute while cooling the tissue to below -25°C, preferably to a temperature of -45°C to -25°C It has been shown that a very high proportion of the cells cooled in this way die as a result.This temperature range is particularly useful in those applications in which the low temperatures are used for the targeted killing of cells in a spatially narrowly defined area.

In other embodiments, the amount of cryogenic liquid applied is metered to cool the temperature of the cells to about 0.5°C to 15°C. This leads to a local suppression of pain sensations and can, for example, be carried out in addition to local surgical, e.g. laser-based interventions. For example, initially on a specific tissue to be operated on or treated with a laser with the

Driickkonf dip krvoppnp Flii<;<;ipkpit aufpptrappn wprdpn so that there P PÖP locally strong ah- is removed using a scalpel or laser or has already been removed in a previous treatment step.

For example, a control device can control the amount of cryogenic liquid delivered via the printhead per unit of time and/or the position of the printhead relative to the surface in such a way that the amount and frequency of the applied droplets ensures that the temperature of the tissue surface and/or the cells within an in vivo or in vitro tissue is maintained within a predefined temperature range for a predefined period of time. The temperature range and the depth profile of the temperature range depend on the respective application (cryogenic destruction of cells or pain reduction, depth and 3D structure of subcutaneous structures (e.g. warts, cancerous growths, etc.).

According to embodiments, the method is repeatedly applied to the same surface multiple times, e.g., twice or three times, e.g., multiple times within an hour or multiple times within a second. This can further increase the proportion of dead and/or thermally inactivated cells.

According to embodiments, the controller is configured to control the application of droplets of the cryogenic liquid to the surface such that the application is continuous and maintains discrete areas on and below the surface at a defined temperature for a defined period of time.

According to one embodiment, the device has multiple containers for multiple volumes of cryogenic liquid. The printhead has a plurality of nozzles, each fluidly connected to one of the reservoirs. The containers contain different cryogenic liquids and/or cryogenic liquids of different temperatures. This makes it possible, similar to inkjet printing, to cool down very finely granular surface areas and/or tissue areas to a specific temperature by complex control of the print pattern generated by the individual printing nozzles.

For example, the printing process can be controlled in such a way that a first cryogenic liquid from a first container with a particularly low temperature is applied in high droplet density by a first nozzle onto a first area of the surface, under which the 7pntrum dps 711 yprstörpndpn GPWPHPS (7th R War7P Krphsppswear ptc ) hp- Drop-densely applied to surrounding, "second" areas of the surface. The surrounding skin and tissue areas are cooled, but at temperatures above 0°C, to avoid ice formation.

In addition or as an alternative to this, the device has a plurality of nozzles which can be controlled individually and emit droplets of the cryogenic liquid of different sizes and/or different frequencies. This also makes it possible to cool down very finely granular surface areas and/or tissue areas to a specific temperature by complex control of the print pattern generated by the individual print nozzles.

For example, the printing process can be controlled in such a way that a first nozzle applies the cryogenic liquid in a high droplet density and/or with a large droplet volume to a first area of the surface, below which the center of the tissue to be destroyed is located. The tissue is cooled to such an extent that the cells die as a result of the cell walls being perforated by ice crystals. In addition, a second nozzle applies the cryogenic liquid in a low droplet density and/or with a small droplet volume to surrounding, "second" areas of the surface. The surrounding skin and tissue areas are cooled here, but to temperatures above 0°C to avoid ice formation .

"Small" or "large/high" drop density or volumes can be a relative specification, which means, for example, that a "small" drop has a volume that is at least 20% smaller than a "large" drop or that a "small " Drop density is at least 20% less than a "large" drop density.

This can be advantageous because a cryo-based destruction of tissue and a cryo-based, non-destructive cooling of surrounding tissue for the purpose of reducing pain can be carried out in a single application step. In some cases, low temperatures are already being used to relieve pain during surgical interventions (e.g. with scalpels or lasers). However, these methods have the disadvantage that they are associated with a high outlay in terms of equipment (additional cryogenic devices are required in addition to the surgical devices). In contrast, embodiments of the invention can have the advantage that the surgical intervention and the cooling for pain relief can be carried out in a single work step and with the same device. also has dpn Vortpil pinpr vprhp<;<;prtpn spatialpn coordination between A "cryogenic liquid" is used here to refer to a liquid that is used to cool objects by applying this liquid, e.g. in technical applications or scientific experiments. Typically, a cryogenic liquid has a temperature below 0 °C. For example, the cryogenic liquid be a liquid gas that is generated, for example, by central facilities or commercial providers by liquefying the corresponding gases (for air/nitrogen, for example, using the Linde process) and brought to the respective application in special transport containers be, for example, liquid nitrogen and/or liquid helium, hydrogen, nitrogen, argon, oxygen or mixtures of two or more of the aforementioned gases.

The cryogenic liquid used for biological, medical and/or cosmetic purposes can in particular be liquid nitrogen or other non-toxic, biocompatible cryogenic liquids.

The use of cryogenic liquids makes it possible to achieve very high freezing speeds and is less dangerous to handle (risk of explosion and fire) than liquid oxygen, for example.

According to embodiments, the print head is designed as a matrix print head in which an application pattern or print image is generated by the targeted firing or deflection of small liquid droplets. For example, the printhead may be a drop-on-demand printhead, i.e., a printhead that fires a single drop.

According to embodiments, the printhead is configured to generate droplets having a droplet size of less than 100 picoliters (pl), preferably less than 10 picoliters. The production of such fine droplets can have the advantage that a particularly finely structured pattern can be produced. Top devices are in the range of 1 pl to 5 pl. For example, the droplets can be sprayed at a frequency of more than 10,000 drops/second. According to embodiments, the print head contains a plurality of print nozzles that can emit the droplets at a nozzle-specific frequency, with the nozzles being able to be controlled individually and droplets being able to be generated at different frequencies. The generation of very small droplets in high and preferably variabe adjustable - Scar tissue, especially excessive scar tissue (keloid);

- Warts, especially stilt warts and molluscum warts (Molluscum contagiosum),

- fibroma molle tumors,

- Lentigo solaris lesions,

- hemangiomas,

- Fire Maie,

- keratoses, in particular seborrheic keratosis;

- skin changes caused by skin cancer.

For example, the removal of pigment spots, scar tissue, port-wine stains, warts and/or keratoses can serve aesthetic purposes.

According to embodiments, the use is:

- a cryosurgical procedure, in particular a local dermatological procedure; and or

- an interventional therapy method for tumors, e.g. therapy for liver metastases, lung or prostate tumors;

- a procedure for the temporary or permanent inactivation or destruction of nerve cells, e.g. pain therapy for phantom pain or to reduce pain caused by surgical interventions.

For example, the temporary inactivation of nerve cells to reduce surgery-related pain can be carried out before, during or after the operation. Preferably, the operation is a cryosurgical procedure performed by the same device that performs the cryogenic liquid for pain relief. Preferably, the cryosurgical intervention and the pain treatment intervention are controlled and performed together in a single work step.

A cryogenic jet of at least 5 milliseconds with liquid nitrogen can already bring about significant pain relief.

According to embodiments, the surface is human or animal skin in vivo or in vitro. An "in vitro" skin is a two-dimensional or three-dimensional cell structure that consists of or contains skin cells and is cultivated using various methods on nutrient media or nutrient substrates. Very generally, "in vitro" tissues such as in vitro organs are involved or organ parts to those cultured outside of a human or animal organism in an artificial environment.

Regular "printing" of surface areas of this cell assembly with cryogenic liquid allows the growth of the cells to be controlled locally in a defined manner. Areas of the cell assembly that have been cooled regularly grow more slowly, and cell death occurs with strong cooling. Thus, the growth of skin cells in 2D and/or 3D can be influenced locally in a targeted manner, thereby giving the tissue cultivated (e.g. for transplantation purposes) a certain shape.

Growth control of "in vitro" skin and other "in vitro" cell aggregates can be advantageous for several reasons:

On the one hand, this enables very fine-grained local growth control. Growth-inhibiting active ingredients can hardly be applied locally because they diffuse in the medium. The cryogenic liquid can also be used to control the cell inhibition over time, as it can be ended or extended at any time. On the other hand, growth-inhibiting substances can no longer be removed from the cell culture medium.

It is also a digitally controlled, fully automatic printing process which can be carried out fully automatically, regularly and under sterile conditions. For example, the pressure device can be completely integrated into a sterile incubator for cell cultures, so that it is not necessary to open the incubator to carry out manual steps manipulating cell growth.

The "in vitro" synthesis of skin and other organs is a field with very great medical potential. It has been shown for some cell types that they grow on a matrix (e.g. cartilage cells on a matrix of jellyfish collagen). The matrix enables It is possible to determine the 3D structure of the cells. However, this is not possible for all cell types. The selective inhibition of cell growth by reducing the

Tpmnpratiir «jchpint ipdoch iinivprspll for allp 7plltvnpn anwpndnar 711 pin da dip wax and/or apply a two- or three-dimensional structure to the surface. The cryogenic liquid is applied, for example, at least before one of the structuring steps in order to influence the subsequent structuring step. For example, a structuring step takes place through the application of the cryogenic liquid.

Embodiments can have the advantage that local structuring processes of a substrate can be controlled through the use of the cryogenic liquid. For example, the surface temperature can be varied locally with pinpoint accuracy by applying the cryogenic liquid. Physical and/or chemical processes affecting the surface can depend on the corresponding surface temperature. For example, chemical reaction rates can be controlled. For example, a deposition rate can be temperature-dependent and structure formation on the surface can thus be controlled. For example, a chemical removal process, such as an etching process, can be temperature dependent and thus the rate of removal can be controlled by controlling the local temperature. For example, a synthesis reaction in the course of a polymerization, i.e. a synthesis reaction which converts identical or different monomers into polymers, can be temperature-dependent. A corresponding polymerization process can be locally controlled by a local temperature variation.

According to embodiments, the structuring step is a chemical reaction, a physical deposition step and/or a polymerization.

According to embodiments, a reaction speed of the chemical reaction is controlled locally by the application of the cryogenic liquid.

According to embodiments, the application of the cryogenic liquid locally changes an aggregate state of a substance involved in the chemical reaction, the physical deposition step and/or the polymerization.

A local temperature variation can locally vary the states of aggregation. For example, the substances involved can be converted from a gas phase into a liquid or solid phase by cooling. A corresponding change in the state of aggregation can influence a chemical reaction, a physical separation step iind/odpr pinp Pnlvmprisatinn hahpn Rpi ni kw i cannpn by pinpn Phaspn- Embodiments can have the advantage that the cryogenic liquid can be used, for example, for structuring a substrate on which a circuit is to be printed. The structuring can create a structural requirement that is necessary for the imprinting or the geometric configuration of the circuit.

According to embodiments, the cryogenic liquid is used to produce a component. The component is, for example, an electronic component. The electronic component is, for example, an integrated electronic circuit, for example based on silicon and/or germanium or on a polymer electronic basis.

The component can be, for example, an electronic component, a mechanical component and/or a component that provides a specific surface structure. Such a surface structure can be used, for example, to support, prevent and/or control a mechanical, electromagnetic or chemical process. Mechanically, the surface structure can, for example, support, prevent and/or control mechanical movements, for example of atoms, molecules or moving elements on the surface. Electromagnetically, the surface structure can, for example, support, prevent and/or control electromagnetic interactions on the surface or across the surface. Chemically, the surface structure can, for example, support, prevent and/or control a chemical process, for example as a catalyst or inhibitor.

According to embodiments, the cryogenic liquid is applied before a doping step in order to locally modulate a doping.

Embodiments can have the advantage that doping can be locally modulated by local temperature control using the cryogenic liquid. For example, doping can take place by means of diffusion. Diffusion is a thermally activated balancing process of a concentration difference, for example in a solid. If there is a concentration difference, foreign atoms can, at sufficiently high temperatures, pr pindrinppn and I hpwpppn Dip pntsnrpchpndp Rpwppun? dpr Frpmdatomp In a further aspect, the invention relates to a device designed for carrying out the use of a cryogenic liquid according to one of the embodiments described here. The device is configured, for example, for one or more or each of the aforementioned embodiments of using the cryogenic liquid.

In a further aspect, the invention relates to a device for applying a cryogenic liquid to a surface to influence a temperature of the surface with a container for holding the cryogenic liquid, a digital print head which is fluidically connected to the container and a control device for controlling the print head for dropwise application of the cryogenic liquid to the surface.

Embodiments can have the advantage that a corresponding device can be provided, for example in the form of a printing unit, which prints the cryogenic liquid drop by drop onto the surface using the digital print head. The dropwise application is controlled by a control device. For the control, the corresponding control device uses control data, for example. The corresponding control data can result, for example, from a distribution scheme provided for applying the cryogenic liquid. In other words, the control data can translate the corresponding distribution scheme into control commands, with which the control device controls the printing unit. The control device can be a device integrated into the printing unit or, for example, a computer system to which the printing unit is connected.

According to embodiments, the print head contains a plurality of individually controllable nozzles. Each of the nozzles is configured to control the size and/or frequency of droplets ejected from the respective nozzle in response to control data from the controller.

According to embodiments, the device is a medical device, in particular a medical device for the selective application of the cryogenic liquid to an organ or a part of an organ. The organ or organ part can be an in-vivo or in-vitro organ or organ part. The organ can in particular be human or animal skin. The medical device can also be pin Gpr t 711m splpktivpn Aufhrinppn dpr krvoppnpn Flüssipkpit on pinzplnp and is 0.05 millimeters thick. The horny layer on the palms of the hands and the soles of the feet is up to several millimeters thick ("cornea"). The dermis consists mainly of connective tissue fibers and serves to nourish and anchor the epidermis. It contains blood vessels, nerves and the smooth muscles that are important for temperature regulation and blood vessels. The hypodermis contains the larger blood vessels and nerves for the upper skin layers as well as the subcutaneous fat and loose connective tissue. The subcutaneous tissue contains sensory cells for strong pressure stimuli, for example the lamellar bodies.

By appropriate control of the print head, all skin layers can be cooled to temperatures below 10°C, also below 0°C, also below -20°C, also below -40°C for a predefined period. This can destroy tissue and/or reduce the activity of the nerves located therein, in particular for the purpose of pain relief).

According to embodiments, the device can be embodied as a tool with a shape that enables the print head to be guided and positioned with one hand. The shape can in particular have the form of a pen, painting or drawing implement.

For example, the device may have an elongate shape and the print head mounted at the front end of the device. Preferably, the device has a holding portion designed to allow the device to be picked up and guided by a human hand. For example, the holding area can have a depression or taper and/or consist of elastic material.

Additionally or alternatively, the device can be an endoscope. For example, the device can comprise a first unit, which contains the container and the control device, and a second unit, which is intended for introduction into the body in order to destroy metastases or other undesirable tissue formations there and/or temporarily or permanently to individual nerves disable. The second unit contains the print head and optionally further elements (camera, temperature sensor, possibly surgical forceps, laser, etc.) and is coupled to the first unit via a preferably flexible connection.

Rp nipkwpi p can p<; I hi dpr Vorrichtiinp urn pin Fndoskon with in r Kampra han- According to another embodiment, the device is a pressure device that is an integral part of a device for the automated cultivation of one or more cell cultures.

According to another embodiment, the device is an apparatus designed to be movable in two or three dimensions for charging the individual cells and/or the organ or part of an organ, in particular an organ or part of an organ cultivated in vitro, with the cryogenic liquid. According to embodiments of the invention, the apparatus includes a temperature sensor and is designed to detect the surface temperature of the organ or organ part during exposure to the temperature sensor and to use it to regulate exposure. For example, the number, size and/or exit velocity of the cryogenic droplets and/or the distance or angle of the print head relative to the surface can be adjusted such that the temperature of the surface is within a predefined temperature range. This very fine-grained control of the surface temperature can be particularly advantageous when biological material is exposed, since temperatures that are too low can lead to the destruction of individual cells or entire tissue. The death of cells should be avoided in application scenarios in which it is only a matter of locally slowing down cell growth or relieving pain. But also in applications in which specific tissue areas are to be destroyed, a narrow focus of the application area is advantageous since damage to the surrounding tissue can be prevented.

For example, in some embodiments, the device may be configured to adjust the surface temperature to a range that slows cell growth but does not result in cell death. In particular, the device can be configured so that when the tissue or the organ or part of an organ is exposed to a cryogenic liquid, the surface temperature is within a target temperature, with the target temperature being selected such that tissue damage and cell death is avoided. For example, by means of such a target temperature, the achievement of which is continuously checked via the - preferably contactless - temperature sensor, the application process can be regulated in such a way that the cryogenic droplets are already in contact with dpr before they reach the surface of the cells or tissue 7PIIP prfolet «jondprn dip Kühhin? indi- The other embodiments of a device described here for applying a wide variety of biological and non-biological materials can also be equipped with a - preferably contactless - temperature sensor and/or can be configured to carry out the application in such a way that the temperature of the exposed surface is within a target temperature range , which excludes damage to the material. Such a temperature range can, for example, be a temperature range in which a cooling effect only takes place via the ambient air, because the droplets have evaporated before they reach the surface.

In a further aspect, the invention relates to a system for producing a component, in particular an electronic component, comprising a device according to one of the embodiments described above. The surface is a substrate. In the course of manufacturing the component, the system carries out one or more structuring steps in order to structure the surface and/or to apply a two-dimensional or three-dimensional structure to the surface. The cryogenic liquid is applied by the device, for example, at least before one of the structuring steps in order to influence the subsequent structuring step. For example, a structuring step takes place through the application of the cryogenic liquid. The component can be, for example, an electronic component, a mechanical component and/or a component that provides a specific surface structure. Such a surface structure can be used, for example, to support, prevent and/or control a mechanical, electromagnetic or chemical process. Mechanically, the surface structure can, for example, support, prevent and/or control mechanical movements, for example of atoms, molecules or moving elements on the surface. Electromagnetically, the surface structure can, for example, support, prevent and/or control electromagnetic interactions on the surface or across the surface. Chemically, the surface structure can, for example, support, prevent and/or control a chemical process, for example as a catalyst or inhibitor.

Embodiments can have the advantage that the cryogenic liquid can be used in the course of manufacturing a component, such as an electronic component, for controlling physical and/or chemical processes. For example, a system for producing a corresponding component includes a corresponding

Press pinhpit with wplchpr dip krvoppnp flii<;<;ipkpit tmnfchpnwp p on pinpr Ohprflächp pi- a structuring step. In this case, a pressure unit can be provided, for example, which prepares the surface accordingly by applying the cryogenic liquid. Structuring then takes place in an adjacent structuring unit, into which the treated surface is transferred.

In the following, embodiments of the invention are explained in more detail with reference to the drawings. Show it:

FIG. 1 is a schematic view of an exemplary apparatus for applying a cryogenic liquid;

FIG. 2 is a schematic view of an exemplary pressure unit for applying a cryogenic liquid;

FIG. 3 is a schematic view of an exemplary pressure unit for applying a cryogenic liquid;

FIG. 4 shows a schematic view of an exemplary system for producing a component;

FIG. 5 shows a flow chart of an exemplary method for applying a cryogenic liquid;

FIG. 6 shows a flow diagram of an exemplary method for applying a cryogenic liquid;

FIG. 7 shows a flow diagram of an exemplary method for applying a cryogenic liquid;

FIG. 8 shows a schematic view of an exemplary device for the cryosurgical application of a cryogenic liquid;

FIG. 9 shows a schematic view of an exemplary device for manual application of a cryogenic liquid in vitro; and

FIG. 10 shows a schematic view of an exemplary device for the automatic application of a cryogenic liquid in vitro.

Elements of the following exemplary embodiments which correspond to one another or are identical are each identified with the same reference symbols.

FIG. 1 shows an exemplary device 100 for applying a cryogenic liquid 103 dropwise to a surface 112 of an object 113. For example, pinp pushbutton 104 hprpitpp tpllt WPICHP pinpn pushbutton 106 is included. wplchpr about that cryogenic liquid 103 to be applied is located. For example, one or more print heads 106 can be provided, which can be moved in two or three spatial directions by a movement unit 107 . The print heads 106 can, for example, each comprise one or more individually controllable nozzles. For example, each of the nozzles may be configured to control the size and/or frequency of droplets ejected from the respective nozzle in response to commands from a controller 102 . A protective atmosphere can prevail inside the printing unit 104, for example. Furthermore, the pressure in the printing unit 104 can be increased or decreased compared to the normal pressure of the environment.

The control device 102 can be a computer system or a computer device, for example. The corresponding computer device can include hardware 114 with one or more processors and a memory in which program instructions are stored for controlling the computer system 102 and the printing unit 104. To receive inputs, the control device 102 can input devices, such as a keyboard 116 and/or a mouse 118. Furthermore, the control device can comprise a display device 120, such as a screen, on which a graphical user interface or GUI ("Graphical User Interface") is displayed. The corresponding graphical user interface 122 can, for example, display an image 127 of the surface 112 as well as a distribution scheme 126 which displays an intended distribution of the cryogenic liquid on and/or over the surface 112 . For example, the graphical user interface 122 may include controls 124 to confirm a proposed distribution scheme 126 and/or to correct the corresponding proposal. A user can confirm the proposed distribution scheme 126 and/or make corrections to the proposed distribution scheme 126 by means of the corresponding control elements 124 using the input devices 116 , 118 . For example, to capture the image 127 of the surface 112, the device 100 may further include a capture device. The corresponding detection device can be, for example, a visual detection device such as a camera. In particular, the detection device can be a microscope. Structure elements to which the cryogenic liquid 103 is to be applied can be determined on the basis of the image 127 of the surface 112 . For example, a distribution scheme 126 can be determined based on an image recognition of already existing structures of the surface 112 using the image 127 FIG. 2 shows a detailed view of an exemplary printing unit 104 from FIG. 1. The corresponding printing unit 104 includes a print head 106. The corresponding print head can include one or more printing nozzles. A position of the corresponding print head relative to the surface 112 can be controlled by a movement unit 107, for example. The corresponding movement unit 107 makes it possible, for example, to move the print head 106 relative to the surface 112 in 2D, ie in a plane parallel to the surface 112, and/or in 3D. Thus, for example, in the case of a 3D method, a distance D of the print head 106 from the surface 112 can be set. For example, the corresponding distance D can be varied, in particular depending on a 2D position relative to the surface 112. Furthermore, the distance D can be kept constant and/or kept constant within a predetermined interval. Furthermore, a minimum distance between the print head 106 and the surface 112 can be maintained, for example, by regulating the distance D. Furthermore, an angle a can be varied, at which the print head 106 applies the cryogenic liquid to the surface 112 drop by drop. A corresponding variation of the angle a can take place, for example, by pivoting the print head 106 about one, two or three pivot axes which are perpendicular to one another.

For example, a protective atmosphere can be generated within the pressure unit 104 and/or the prevailing pressure can be regulated. By using a protective atmosphere and/or regulating the pressure under which the cryogenic liquid is applied to the surface 112, the effect of the cryogenic liquid, in particular the effect on the surface and/or on substances involved in physical and/or chemical reactions, can be targeted be controlled locally. Furthermore, the effect of the substances involved in the physical and/or chemical reactions can be controlled by using a protective atmosphere and/or by regulating the pressure.

FIG. 3 shows a further exemplary embodiment of a printing unit 104 which comprises a plurality of print heads 106. The movement unit 107 can be designed, for example, so that the individual print heads 106 can be moved independently of one another in 2D and/or 3D. Furthermore, the corresponding print heads can, for example, be pivoted independently of one another about one, two and/or three pivot axes which are perpendicular to one another.

Fiei ir 4 7Pi?t pi np An lapp 1 0 7 iir Hp r tp llu np pi np<; Ra i ip lp mpnt"; i n<;hp<;nnnp rp pi np<; p lp kt The application of the cryogenic liquid can, for example, take place simultaneously with a structuring of the surface 112 . In this case, the printing unit 104 would be integrated into the structuring unit 109 . Alternatively, the cryogenic liquid can be applied before a corresponding structuring step, as shown in FIG. In this case, for example, the cryogenic liquid is applied to the surface 112 of the object 113 by means of the print head 106 that can be positioned using the movement unit 107 . The application can take place, for example, according to a previously defined distribution scheme. The corresponding object 113 is then transferred to the structuring unit 109 . For example, the same atmospheres prevail in the printing unit 104 of the structuring unit 109, in particular a protective atmosphere. Furthermore, the pressure in both units 104, 109 can be identical. Alternatively, the pressures prevailing in the units 104, 109 could differ.

The structuring unit 109 can be, for example, a unit that is configured to carry out a chemical reaction, a physical deposition step and/or a polymerization. For this purpose, the structuring unit 109 provides, for example, the substances involved in the corresponding structuring step and controls the physical framework conditions. A local temperature variation for influencing the structuring step then occurs, for example, through the local distribution of the cryogenic liquid.

FIG. 5 shows a flow chart of an exemplary method for applying a cryogenic liquid to a surface. In block 204, a distribution scheme is created. A corresponding distribution scheme can be specified or set by a user, for example. Alternatively, a distribution scheme can be based on a predefined structure to be produced of the surface to which the cryogenic liquid is to be applied. For example, a corresponding structuring template is provided, which defines the predefined structure to be produced. For example, the distribution scheme can be a distribution of the cryogenic liquid according to the predetermined structural shapes. The distribution scheme for distributing the cryogenic liquid on and/or over the surface can define, for example, where, when, how much cryogenic liquid is to be applied and whether the applied cryogenic liquid is to reach the surface or not. For example, the distribution scheme defines a spatial and/or temporal distribution of the cryogenic liquid. Example- wpi p dpfiniprt da«; prtpiliinp<;<;chpma pinp räiimlichp iind/ndpr 7Pilichp variiprpndp Ahea- includes both a direct and an indirect temperature influence on the surface.

In block 210, control data is generated using the distribution scheme. The corresponding control data are, for example, control commands for controlling one or more print heads for applying the cryogenic liquid to a surface. For example, the control data can define at which positions of the printhead relative to the surface, how much cryogenic liquid is to be applied and at what angle. In block 212, an appropriate device, such as a pressure unit, is controlled to apply the cryogenic liquid to the surface using the control data. In other words, the cryogenic liquid is dispensed over the surface and/or the cryogenic liquid is applied to the surface according to the distribution scheme generated in block 204 . Subsequent to or at the same time as the application of the cryogenic liquid, for example, further physical and/or chemical processes can be carried out in a controlled manner, which are influenced by the local temperature change caused by the cryogenic liquid.

FIG. 6 shows a flow chart of an exemplary method for applying a cryogenic liquid which, in addition to the method shown in FIG. 5, includes detecting a structure of the surface in block 200. A corresponding detection of a structure of the surface can be advantageous, for example, if the physical and/or chemical processes which are to be influenced by the application of the cryogenic liquid depend on predetermined structures of the surface. In this case, the structure of the surface is recorded in block 200, for example. In block 202, structural elements are determined to which the cryogenic liquid is to be applied. The corresponding determination of the structure elements can take place, for example, by input from a user and/or can take place automatically. In the case of an automatic determination of the structural elements, a method for image recognition can be used, for example. The corresponding structural elements can be determined, for example, based on their geometry and/or their visual appearance, such as their color. The distribution scheme in block 204 is generated, for example, based on the determined structural elements such that the positions at which the cryogenic liquids are applied to the surface correspond to the positions of the structural elements.

For example, nip meneen of the applied kvoeenen Fl i issiekeit in Ah- Controlling a corresponding device for applying the cryogenic liquid is used. Subsequent to or at the same time as the application of the cryogenic liquid, for example, further physical and/or chemical processes can be carried out in a controlled manner, which are influenced by the local temperature change caused by the cryogenic liquid.

FIG. 7 shows a flow chart of a further exemplary method for applying a cryogenic liquid to a surface. As in the method according to FIG. 6, the structure of a surface to which the cryogenic liquid is to be applied is first detected in block 200 . In block 202, structural elements are determined which are to be at least partially covered with the cryogenic liquid. At block 204, a distribution scheme for applying the cryogenic liquid is generated using the determined structural elements. In block 206, the generated distribution scheme is displayed on a display device, for example. In block 208, a user's confirmation of the distribution scheme is received. Alternatively, corrections to the distribution scheme can be received and the displayed distribution scheme corrected accordingly. For example, after the corrections have been completed, the correspondingly corrected distribution scheme is confirmed. In block 210, which presupposes, for example, the confirmation of the distribution scheme, control data for controlling a device for applying the cryogenic liquid according to the distribution scheme is generated. Finally, in block 212 the corresponding device is controlled using the control data generated in block 210 . Simultaneously and/or subsequently to the application of the cryogenic liquid, one or more further physical and/or chemical processes can take place in a controlled manner, which are controlled locally by the local temperature control using the cryogenic liquid.

FIG. 8 shows an exemplary device 700 for applying a cryogenic liquid 708 to a surface 712 for use in a medical or cosmetic context. For example, the device can be used to destroy or remove skin lesions. The apparatus includes a container 702 for holding the cryogenic liquid, a digital printhead 706 fluidly connected to the container, and a controller 704 for controlling the printhead to apply the cryogenic liquid dropwise to the surface.

Rpi dpr device 700 can p<; So I urn pin mpniyintpchnischps Gpraet inshpsondprp The surface 712 can be, for example, the epidermis of human or animal skin 710 or some other surface of individual cells or a cell assembly.

Human skin is divided into three main layers: epidermis (upper skin), dermis (corium in Latin) and subcutis (lower skin). The epidermis is a stratified squamous epithelium usually between 0.03 and 0.05 millimeters thick. The horny layer on the palms of the hands and the soles of the feet is up to several millimeters thick ("cornea"). The dermis consists mainly of connective tissue fibers and serves to nourish and anchor the epidermis. It contains blood vessels, nerves and the smooth muscles that are important for temperature regulation and blood vessels. The hypodermis contains the larger blood vessels and nerves for the upper skin layers as well as the subcutaneous fat and loose connective tissue. The subcutaneous tissue contains sensory cells for strong pressure stimuli, for example the lamellar bodies.

By appropriate control of the printhead, all skin layers can be cooled to temperatures below 10°C, also below 0°C, also below -20°C, also below -40°C for a predefined period. As a result, tissue can be destroyed and/or the activity of the nerves located therein can be reduced, in particular for the purpose of relieving pain before, during or after a local operation.

The application of the cryogenic liquid is preferably not carried out according to the "all or nothing" principle, but via a large number of nozzles which can be controlled individually and eject the droplets of the cryogenic liquid in such a way that the droplet ejection of the various nozzles differs in terms of size and/or or frequency. This can result in complex patterns that adapt individually to the skin and subcutaneous structures to be treated. For example, it is even possible to produce ring-shaped pressure patterns with very strong cooling, so that the cells within the ring-shaped pressure pattern die but the cells in the center not. Such structures occur again and again in various skin lesions. With conventional devices that work according to the "all or nothing principle" (on-off principle), it was not possible to treat such structures in the most gentle way possible, since all tissue to which the cryogenic liquid has been applied died, although often only a part should really be removed. The use of a print head with several individually controllable harpn Dii pn p<; dappppn also knmnlpxp Hautlä innpn pinsc.hlipRIic.h «jolchpr dip Heat loss from human skin in contact with air is negligible since air is an excellent thermal insulator. The application of the cryogenic liquid causes a significant cooling of the surface to which the droplets are applied, with the cold also spreading to the underlying tissue, particularly if cryogenic liquid droplets continue to be applied to that surface location by the print head.

Lateral thermal diffusion and cooling by blood perfusion favored the propagation of cooling into the tissues, which may take a few seconds. The cryogen applied to the skin creates a heat sink beneath the skin's surface, formed as a temperature gradient. The steeper the gradient, the faster a given amount of heat is extracted. Thus, to be successful, the cryogen should produce a large drop in surface temperature as quickly as possible.

FIG. 9 shows a manually operable device 800 for applying the cryogenic liquid in vitro. For example, flat 2D or 3D cell structures, such as bacterial cell structures (“biofilm”), artificial skin, artificial cartilage, associations of liver cells, muscle cells, etc., can increasingly be cultivated in vitro, here, for example, in a Petri dish 802. By manual and preferably repeated application of a cryogenic liquid to certain areas of the cell assembly, the growth of the cells, including the three-dimensional growth, can be controlled. The print head 706 is positioned manually on the areas of the cell assembly that are to be destroyed or slowed down in growth. Instead of a petri dish, you can also Cell culture dishes of different sizes and formats can be used A highly localized application of a cryogenic liquid can be used not only for medical and cosmetic purposes but also for scientific questions, for example to promote metabolism and cell growth in certain areas amen or the cell metabolism selectively in a selected region by very rapid cooling to below 0°C for further analysis.

FIG. 10 shows a device 900 for the automatic application of the cryogenic liquid via a print head 706 in vitro. The device 900 is attached to a movable element 902 in a rigid or movable (eg rotatable and/or pivotable) manner. With the hpwpplichpn Flpmpnt, p<; I 7 R um pinpn Rohotprarm odpr pinp otherwiseripp automa- The automatic drip application of cryogenic liquid via printhead 706 may have the advantage of increasing control over exactly where cryogenic liquid is applied. Corresponding embodiments are therefore particularly suitable for high-precision applications. The print head 706 preferably has a plurality of individually controllable print nozzles.

In one embodiment, the device and the arm 902 are an integral part of an incubator or other device that is used to control the temperature and optionally also to move one or more prokaryotic or eukaryotic cell cultures. This can have the advantage that the device can be regularly positioned on certain surface areas of the cell assembly in order to apply the cryogenic liquid there and to control cell growth. Since both the device 900 and the movable unit 902 are part of the incubator or device, a cryotreatment can be carried out repeatedly without increasing the risk of infection.

Reference List

100 device

102 control device

103 cryogenic liquid

104 printer unit

105 manufacturing facility

106 print head

107 movement unit

108 containers

109 structuring unit

110 fluidic conduit

111 droplets of cryogenic liquid

112 surface

113 object

114 hardware component

116 input device

118 input device

120 screen

122 graphical user interface

124 controls

126 distribution scheme

127 surface image

700 device for medical or cosmetic cryotreatment

702 Cryogenic Liquid Container

704 control device

706 print head

708 droplets of cryogenic liquid

710 skin

712 surface

800 device for in vitro cryotreatment

802 petri dish/cell culture vessel

900 devices to Krvohphandhinp

Claims

patent claims

1. Use of a cryogenic liquid (103), characterized in that the cryogenic liquid (103) is applied dropwise, digitally controlled, to a surface (112, 712) in order to influence a temperature of the surface.

2. Use according to claim 1, wherein the digitally controlled application of the cryogenic liquid (103) determines a position of the application in 2D or 3D, a volume of the application and/or an angle of the application relative to the surface (112, 712 ) is controlled, whereby the volume and/or the angle can be position-dependent.

3. Use according to claim 1 or 2, wherein the cryogenic liquid (103) is stored in a container (108, 702) which is fluidly connected to a digital print head (106, 706), the digital print head (106, 706) is controlled digitally for the dropwise application of the cryogenic liquid (103) to the surface (112, 712).

4. Use according to claim 3, wherein the digital print head (106, 706) is movable relative to the surface (112, 712).

5. Use according to one of the preceding claims, wherein the surface (112, 712) before the application of the liquid (103) has a temperature of more than 50°C, more than -20°C, in particular more than 0°C, or room temperature or body temperature of an animal or human.

6. Use according to one of the preceding claims, in which the surface (112, 712) has a maximum temperature of 100° C. before the liquid (103) is applied.

7. Use according to one of the preceding claims, wherein the application of the cryogenic liquid (103) takes place under a protective atmosphere, in particular under a protective atmosphere with increased or reduced oxygen pphalt rplativ 711 r normal atmosphere <;nhärp 35

9. Use according to one of the preceding claims, wherein the cryogenic liquid (103) is helium, hydrogen, nitrogen, argon, oxygen, carbon dioxide or a mixture of one or more of these substances.

5

10. Use according to any one of the preceding claims, wherein the use further comprises:

• Detecting a 2D and/or 3D structure of the surface (112, 712) and/or an object (113) that includes the surface (112, 712), 0 • Determining structural elements of the surface (112, 712) on which the cryogenic liquid (103) is to be applied depending on the detected 2D and/or 3D structure; and

• Generation of control data designed to control the application of the cryogenic liquid (103) to the specific structural elements.

11. Use according to claim 10, wherein the use further comprises creating a digital distribution scheme (126) for applying the cryogenic liquid (103) to the specific structural elements depending on the detected 2D0 and/or 3D structure, the control data being designed for controlling the application of the cryogenic liquid (103) to the determined structural elements according to the distribution scheme (126).

The use of claim 11, wherein the digital distribution scheme (126) is displayed on a display device (120) and controlling application of the cryogenic liquid (103) using the control data according to the distribution scheme (126) includes receipt of confirmation of the displayed distribution scheme (126) via an input device (116, 118). 0 13. Use according to one of the preceding claims, wherein the surface (112, 712) is living or dead biological material, wherein the biological material comprises in particular: microorganisms, a cell culture and/or a cell assembly, in particular an internal vivo or in vitro cell assembly, in particular an in vitro cell assembly for the growth of an artificial ^ 14. Use according to any one of the preceding claims, wherein the surface (112, 712) is human or animal skin (710) in vivo or in vitro.

15. Use according to claim 14, wherein the use is a method for the medical and/or aesthetic treatment of skin changes, wherein the skin changes are selected in particular from a group comprising:

• pigment spots;

• Excessive scar tissue (keloid);

• Warts, especially style warts and mollusc warts (Molluscum contagiosum),

• fibroma molle tumors,

• Lentigo solaris lesions,

• hemangiomas,

• fire may,

• keratoses, especially seborrheic keratosis;

• skin changes caused by skin cancer.

16. Use according to one of claims 1 to 15, wherein the surface (112) is a substrate, one or more structuring steps being carried out in order to structure the surface (112) and/or a two- or three-dimensional structure applied to the surface (112), the cryogenic liquid (103) being applied at least before one of the structuring steps in order to influence the subsequent structuring step, or the application of the cryogenic liquid (103) leading to a structuring step.

17. Use according to claim 16, wherein the structuring step is a chemical reaction, a physical deposition step and/or a polymerisation.

18. Use according to claim 17, wherein a reaction rate of the chemical reaction is locally controlled by applying the cryogenic liquid (103) and/or wherein by applying the cryogenic liquid 19. Use according to any one of claims 16 to 18, wherein the surface (112) is a substrate for a printed circuit board.

20. Use according to one of claims 16 to 19 for the production of a component, in particular an electronic component, the electronic component being in particular an integrated electronic circuit based on silicon and/or germanium or on a polymer electronic basis.

21. Use according to claim 20, wherein the cryogenic liquid (103) is applied before a doping step in order to locally modulate a doping.

22. Device (100, 700, 800, 900) designed to carry out the use of a cryogenic liquid (103) according to any one of the preceding claims.

23. Device (100, 700, 800, 900) for applying a cryogenic liquid (103) to a surface (112, 712) to influence a temperature of the surface (112, 712) with a container (108, 702) for receiving the cryogenic liquid (103), a digital print head (106, 706) which is fluidically connected to the container (108, 702) and a control device (102, 704) for controlling the print head (106, 706) for dropwise application of the cryogenic liquid (103) onto the surface (112, 712).

24. Device (700) according to one of claims 22 to 23, wherein the device (700) is a medical device for the selective application of the cryogenic liquid (103) to an organ or a part of an organ, in particular an in vivo or an organ or part of an organ cultivated in vitro, in particular human or animal skin (710), or the device being a device for selectively applying the cryogenic liquid (103) to individual cells, in particular nerve cells.

25. Device (700, 800) according to any one of claims 22 to 24, wherein the device (700, 800) is designed as:

• pin in 7\A/pi nrlpr rlrpi Rimpnuinnpn hpxA/pplirh ai pphilrlptpr Annarat 71 ir Rp- 38 and is designed to detect the surface temperature of the organ or part of the organ during exposure to the temperature sensor and to use it to regulate the exposure; and or

• a tool with a shape that allows guiding and positioning of the

5 print head (106, 706) allows with one hand, wherein the shape has in particular the form of a pen, painting or drawing implement; and or

• an endoscope; and or

• an endoscope with a camera, the camera being mounted at the same end of the device as the printhead (106, 706) and oriented such that the camera is adapted to take images (127) from the printhead (106, 706) and of the contacted by this surface (112, 712) to detect.

The apparatus (100, 700, 800, 900) of any one of claims 22 to 25, wherein the printhead (106, 706) includes a plurality of individually addressable nozzles, each of the nozzles being configured to vary the size and/or frequency of the drops , which are expelled from the respective nozzle, depending on control data from the control device (102, 704). 0 27. Device (100, 700, 800, 900) according to one of claims 22 to 26, further comprising a temperature sensor which is designed for preferably contactless detection of the surface temperature of the substrate to be acted upon by the cryogenic liquid, the device being designed for this purpose to detect the surface temperature of the organ or part of the organ during exposure5 to the temperature sensor and to control the exposure so that the detected surface temperature is within a target temperature range.

28. Plant (105) for producing a component, in particular an electronic component, comprising a device (100) according to any one of claims 0 22 to 27, wherein the surface (112) is a substrate, the plant (105) performs one or more structuring steps during the manufacture of the component in order to structure the surface (112) and/or to apply a two- or three-dimensional structure to the surface (112), wherein at least before one of the structuring steps the application ^