Roll device and system and method for introducing a surface structure in an object

Abstract

The invention relates to a roll device (1) for applying pressure to an embossing element (30) which, during an embossing process, introduces a surface structure in an object, in particular an embossing compound (12), wherein during the embossing process, the roll device (1) acts on the embossing element (30) via a contact face and moves along a translational direction (T) in a rotational manner about a rotational axis (R) in order to act on the embossing element (30) over contact faces which are offset to one another along the translational direction (T), in particular one after the other, comprising: - a core element (2) and - a casing element (3) surrounding the core element (2), wherein the core element (2) and the casing element (3) are designed such that an effect of force acts homogeneously on the embossing element both over the contact face along a direction perpendicular to the translational direction (T) and over a plurality of contact faces which follow one another in the translational direction (T).

Description

[0001] Rolling device and system and method for embedding a surface structure in an object

[0002] The present invention relates to a rolling device as well as a system and a method for embedding a surface structure in an object.

[0003] Rolling devices for forming surface structures are well known.

[0004] A very commonly used roller is the embossing roller. The embossing roller has structures on its outermost surface that are intended to be embossed into an embossing compound. Embossing rollers can be manufactured from a single, solid component. The structures of the embossing roller can then be incorporated directly into the solid surface of the embossing roller. However, some embossing rollers have a solid core made of a solid material and a soft shell containing the embossed structures. In this case, the embossing roller itself is a type of roller stamp and is used directly for embossing.

[0005] WO 2014 037 044 A1 discloses another method for embedding a surface structure into an object. This involves embedding a surface structure in the micrometer or nanometer range into the outer surface of the object. For this purpose, an embossed element designed as a stamp is pressed into the outer surface of the object. The force required for this is applied by a rolling device, which acts via a contact surface on the rear side of the embossed element, thereby causing the embossed element to engage the outer surface of the object, thereby forming the surface structure in the region of the contact surface. By rolling over the rear side of the embossed element, a two-dimensional surface structure is then completely formed to the desired extent. Such a roller can also be referred to as a pressure roller.

[0006] The pressure application roller is primarily used to apply the most uniform line force possible to an underlying embossing element. In particular, the embossing element is a stamp, preferably a soft stamp. The soft stamp can be applied to a carrier substrate, for example. Therefore, instead of an embossing roller, a stamp is used to press embossed structures into an embossing compound; instead, a stamp is applied to the back of which pressure is applied by a pressure application roller.

[0007] A disadvantage of the prior art is that due to the pressure applied to the side of the pressure roller, the linear force is generally no longer homogeneous, and thus the pressure exerted on the stamp is no longer uniform. However, uniform pressure is necessary to correctly press the stamp's embossed structures into the stamping compound.

[0008] For example, a rolling device is also known from the prior art in which a displaceable component preloaded with a spring is provided within a partial section along the circumference. US Pat. No. 5,662,574 discloses a rolling device comprising a casing element and a core element, wherein the core element has an outer circumference that is not completely rotationally symmetrical with respect to the axis of rotation around which the core element rotates.

[0009] In view of the above, the present invention has for its object to provide a rolling device which presses the embossing element into the embossing mass, ie the object to be embossed, with the greatest possible positional accuracy and reproducibility.

[0010] The present invention achieves the object of the present invention by means of a rolling device according to claim 1, by means of a system for embedding a surface structure in an object according to claim 13 and by means of a method for embedding a surface structure in an object according to claim 15.

[0011] According to a first aspect of the present invention, a rolling device is provided for applying pressure to an embossing element, which in an embossing process creates or creates a surface structure in an object, in particular in an embossing compound, wherein during the embossing process the rolling device acts on the embossing element via a contact surface and moves along a translation direction while rotating about an axis of rotation, in particular while maintaining pressure on the embossing element, in order to act on the embossing element via contact surfaces offset from one another along the translation direction, in particular one after the other, comprising: a core element and a casing element surrounding the core element, wherein the core element and the casing element, in particular by their geometric shape along an axial direction orLongitudinal direction of the rolling device, are designed in such a way that a force acts homogeneously on the embossing element both via the contact surface along a direction perpendicular to the translation direction and via several contact surfaces following one another in the translation direction, in particular one after the other.

[0012] In contrast to the rolling devices known from the prior art, the invention provides that the force can be applied homogeneously to the embossed element, in particular over a two-dimensional surface that extends both perpendicular to the translation direction, in particular over more than 50%, preferably over more than 75%, and particularly preferably over more than 90% of the extension of the rolling device, and over several contact surfaces along the translation direction. The rolling device, which is rotatably mounted, for example, in a corresponding holder, comprises, for this purpose, in particular suitable configurations of the core element and the casing element in order to realize the homogenization or homogeneity of the force application over the two-dimensional surface.For this purpose, the rolling device is structurally designed accordingly, for example by a suitable circumferential geometry of the core element and / or an inner side geometry of the shell element, which preferably changes along the axial direction of the rolling device. In particular, it is provided that the radial extent of the core element and / or the shell element in the axial direction changes along a direction that runs perpendicular to the translation direction in order to adjust the homogeneous application of force. The rolling device is, in particular, a pressure application roller. In particular, the shell element surrounds the core element by at least 80%, preferably at least 90%, and particularly preferably at least 95%, and for example, only the end faces of the core element are not enclosed or surrounded by the shell element.

[0013] If the casing element is made of a material whose hardness can be specified in Shore A, the following preferred values ​​apply: The Shore A hardness is between 10 and 100, preferably between 15 and 70, more preferably between 20 and 60, most preferably between 30 and 50, most preferably between 40 and 45. In particular, the homogeneous application of force along a direction perpendicular to the direction of translation is to be understood in comparison to a reference rolling device in which the core element and casing element have the same, in particular constant, geometry along the axial direction or extension.In particular, the reference rolling device comprises a core element and a shell element, both of which do not change their outer circumference along the axial direction, wherein the outer sides of the shell element and the core element are arranged concentrically to each other and their distance measured in the radial direction does not change along the axial direction.

[0014] It has been shown that for such reference rolling devices, a substantially homogeneous force profile cannot be established when the reference rolling device is pressed onto the embossing element during an embossing process. Instead, the result is an uneven, i.e., inhomogeneous, force distribution or force action along the axial extent of the reference rolling device. Compared to such a reference rolling device and its force profile, which is determined along a direction perpendicular to the translation direction, the rolling device according to the invention is, in particular, homogenized, i.e., it has a more homogeneous force profile, i.e., a more homogeneous, spatially distributed force action on the embossing element.

[0015] By appropriate geometric configurations of the shell element and the core element, in particular by varying their outer circumference and / or inner side in the axial direction, this force distribution or the force effect on the embossing element along the axial direction can be homogenized in comparison to the force effect of the reference rolling device.

[0016] This proves to be advantageous for the embossing process, as it can be carried out more precisely, especially when embossing micro- or nanometer structures. In particular, the core element and the shell element have a changing outer geometry and / or circumferential geometry along the axial direction, with which the force acting on the embossing element from the rolling device during the embossing process is or can be specifically influenced. For example, a radially measured distance between an outer circumference of the core element and an outer circumference of the shell element changes along the axial direction, for example, decreasing or increasing towards the center of the rolling device. Furthermore, it is particularly provided that the rolling device is designed so that during a translational movement, ieWhen the rolling device rolls along the translation direction, the successively created contact surfaces between the rolling device and the embossing element cause or experience a homogeneous force on the embossing element, particularly assuming a constant force on the rolling device. This advantageously makes it possible to avoid the need for extensive adjustments to the force effects on the rolling device through additional control processes. This means that only a minor adjustment is required when the rolling device is moved along the translation direction and a two-dimensional surface structure is embedded in the object.This distinguishes it in particular from rolling devices or rolling embossing bodies which, for example, have core elements that are not completely rotationally symmetrical and, for example, have curved sections in a plane running perpendicular to the axial direction which have a different structure or geometry than the rest of the outer circumference of the core element. These deviating partial areas can lead to increased inhomogenisation of the force application when rolling along the translation direction. The rolling device is particularly designed so that, through the suitable geometric configuration or geometric shape of the casing element and core element, it ensures that an essentially homogeneous force application is realised for several successive contact surfaces along the translation direction and also ensures that a homogenised force profile orA force application profile is generated along a direction perpendicular to this translation direction. This advantageously makes it possible to ensure the most homogeneous force application possible across the two-dimensional surface, which has a beneficial effect on the control and precision when embossing and imprinting the surface structure using the embossing element. For this purpose, the outer shape of the core element is modified or modulated along a direction that runs parallel to the axial extension, axial direction, or longitudinal direction.

[0017] In particular, it is provided that the force is applied homogeneously to the embossing element across a plurality of contact surfaces following one another in the translation direction, even if the contact surface changes in size, in particular over a length measured perpendicular to the translation direction, or if the size or length of the object to be processed changes. This is the case, for example, if the object to be embossed has a geometry that deviates from a rectangle and is, for example, round or elliptical. In this case, a controlled, i.e. regulated, application of force ensures that the force applied to successive contact surfaces is nevertheless homogeneous along the translation direction. For example, the application of force is increased for an increasing area to be embossed on the object. For this purpose, an appropriate control unit designed for this purpose is required on the device.Adapting the force application to the contact surface or the surface to be embossed proves particularly advantageous for circular or elliptical objects, such as silicon wafers, which are preferably circular.

[0018] It is preferably provided that an outer circumference of the rolling device is cylindrically shaped, in particular is designed cylindrically in such a way that a constant circular cross-section is set or is set or realized in a plane running perpendicular to the axis of rotation along the entire axial extent of the rolling device.

[0019] Preferably, the embossing element has a stamping region that is particularly designed to embed a micrometer and / or nanometer structure in the object, which is in particular a stamping compound. In particular, the embossing element is designed for a molding accuracy in the micrometer and / or nanometer range. Molding accuracy is understood to be the smallest structure size that can still be produced without defects. The molding accuracy of the embossing element is less than 1000 nm, preferably less than 500 nm, more preferably less than 100 nm, and most preferably less than 10 nm.

[0020] In particular, it is intended that the rolling device be used in a system designed to produce substrates with a defined surface structure, particularly in the micrometer or nanometer range. The substrate is preferably a component for the semiconductor industry, for example, a part of a microchip.

[0021] The contact surface is preferably designed to be substantially linear. In other words, the contact surface for one position (without translational movement) extends over a length parallel to the axis of rotation that is more than 5 times, preferably more than 10 times, and particularly preferably more than 20 times as large as a maximum width of the contact surface measured perpendicular thereto. This applies in particular to a snapshot in which the rolling device acts on the embossing element. In particular, it is provided that an outer circumferential surface of the entire rolling device, determined by the outer circumference of the casing element, is free of surface structures, in particular in order to realize or at least support homogenization here as well.In particular, a homogeneous force application means that the force applications for different points, either for different contact surfaces or for different points within the contact surface, deviate by no more than 15%, preferably no more than 10%, and particularly preferably no more than 5% from an average value of the force applications on the embossed element at the various points or regions. The force application, in particular its spatial or two-dimensional distribution, is determined, for example, by determining the respective force application point-by-point or region-by-region and then reproducing this depending on the spatial distribution, for example using pressure sensors integrated into the rolling device. In the case of a homogeneous force application, an essentially constant force application profile is then formed.

[0022] Preferably, the core element has a circumferential geometry that is completely rotationally symmetrical to the rotation axis, i.e., the circumferential geometry of the core element can be transformed into itself by rotation through any angle. Even if the outer circumference of the core element changes in the axial direction, in particular changes in such a way that a homogenized force profile or a constant force action profile results along the axial direction of the rolling device, it is particularly preferably provided that complete rotational symmetry with respect to the rotation axis exists for the outer circumference of the core element.In other words, concentric circles are provided as the circumferential cross-section for the core element along the axial direction. These circles can change along the axial direction for adaptation with regard to homogenization, but are designed to be circular in circumference to advantageously ensure that homogeneous force effects are realized for successive contact surfaces during the rolling movement in the translational direction. In particular, it is provided that at least for a half, three-quarters, or a complete rotation, the contact surfaces generated during the rotation exhibit a substantially homogeneous force effect or are assigned a corresponding homogeneous force effect profile.This distinguishes it in particular from rolling devices in which the core element at least does not have a circular cross-section formed over the entire axial extent, which leads to different force effects or transmissions being realized at different rotational positions of the rolling device, in particular when a corresponding force is applied to the rolling device.

[0023] Preferably, the core element is made of a first material and the sheath element is made of a second material, with the first material being different from the second material. This advantageously makes it possible to influence the force application, particularly the force application along a line, particularly along a linear contact surface running parallel to the rotation axis, through the choice of material. These are preferably rubber-like materials with different moduli of elasticity. Particularly preferably, the core element comprises a metal and / or the sheath element comprises a plastic.

[0024] Preferably, the circumferential geometry of the core element is variable. This advantageously makes it possible, for example, over several cycles of stamping processes, to create an optimized and adapted circumferential geometry in order to ensure the best possible conditions for the stamping process, particularly with regard to its precision. This also makes it possible to make adjustments over the entire service life of the rolling device if, for example, wear or abrasion of the outer surface requires adjustment in order to ensure precise stamping over the long term. Adjustment in a real-time control loop is also conceivable, particularly if pressure sensors are integrated into the rolling device.

[0025] It is particularly preferred if the circumferential geometry of the core element is adjustable by means of at least one electrode and / or a piezo element in or on the core element. In particular, this advantageously makes it possible to adjust the circumference, in particular its size, using simple electronic control signals. This makes it possible, for example, to adjust and optimize the force applied along the axial direction of the rolling device within a control loop. This preferably takes place automatically or in a preparatory measuring process. It is also conceivable for the circumference of certain core sections to be changed, for example initiated by electrical and / or thermal energy. In this case, it is preferably provided that the circumferential geometry changes or can be changed stepwise or continuously along the axial direction. Furthermore, it is provided that the core element has a core element interior for accommodating a fluid.For example, the core element interior is a cavity that can be filled with a liquid. In particular, it is provided that a wall of the core element, in particular a wall that delimits the core element interior, is elastically deformable. This advantageously makes it possible to specifically induce a curvature by filling the core element interior with the fluid, for example with a gas or a liquid, which in turn can be used to realize a corresponding geometry on the outer circumference of the core element. For this purpose, it is preferably provided that, for example, the thickness of the wall changes along the axial direction in order to realize a corresponding geometry of the core element when the core element interior is filled.

[0026] Furthermore, it is preferred that the rolling device has a connection for fluid communication with the core element interior. For example, an opening is provided on one of the end faces of the rolling device through which a fluid can enter or be sucked out. For example, it is also conceivable that a corresponding vacuum can influence the geometry of the core element to such an extent that a concave outer structure is formed.

[0027] It is preferably provided that the core element has a circumferential geometry with a concave and / or convex profile extending in the axial direction. In this case, it is particularly conceivable for the outer circumference of the core element to be wavy along the axial direction. Furthermore, it is preferably provided that the core element has at least one groove. For example, it is conceivable that a targeted groove sequence or sequence of groove profiles along the axial direction leads to the desired force profile that is to act on the embossing element by means of the rolling device. It is preferably provided that in a preceding simulation step the individual elevations, in particular the grooves or trenches, are determined with regard to their position and / or size and these are then particularly preferably realized in a rotating device.

[0028] Furthermore, it is provided that the rolling device has a core element and a casing element which are of different thicknesses. In particular, it is provided that the casing element has a first extent measured in the radial direction, in particular averaged over an axial extent of the rolling device, and the core element has a second extent measured in the radial direction, in particular averaged over an axial extent of the rolling device, wherein a ratio of the first extent to the second extent assumes a value which is less than 0.2, preferably less than 0.1 and preferably less than 0.05. This expresses that the wall of the casing element is comparatively thin compared to the dimensions of the wall of the core element or the core element itself.

[0029] The diameter of the core element is less than 50 mm, preferably less than 30 mm, more preferably less than 20 mm, most preferably less than 15 mm, most preferably less than 10 mm.

[0030] The material of the core element is preferably taken from one of the following material classes.

[0031] • Metal, especially o Aluminum o Copper o Iron o Nickel

[0032] • Alloy, especially o steel o nickel-based alloy

[0033] Another subject of the present invention is a system for embedding a surface structure into an object, in particular into an embossing compound, using a rolling device according to the invention and the embossing element. All the advantages and properties described for the rolling device can be applied analogously to the system.

[0034] Preferably, the system comprises a roller support for the rolling device, wherein the roller support comprises a means for adjusting the height of the rolling device and / or a signaling device that indicates a maximum position of the rolling device and / or the roller support and / or a spring element. This advantageously makes it possible to realize a system that is as cost-effective as possible, yet is still suitable for embossing precise micro- and nanostructures into an embossing compound. Preferably, the embossing element, for example comprising a support and a stamp, is designed to emboss a micro- and / or nanometer structure into the embossing compound. Preferably, the means for adjusting the height comprises a bellows whose volume can be changed by fluid in order to make the smallest possible changes. The alternative or additional use of a piezo element is also conceivable.

[0035] The present invention further provides a method for embossing a surface structure using a system as described above, wherein a surface structure is embossed into an object, in particular into an embossing compound, in an embossing process. During the embossing process, the rolling device acts on the embossing element via a contact surface and is moved along a translation direction, rotating about a rotation axis, in order to act on the embossing element via contact surfaces offset from one another along the translation direction. All advantages and properties described for the rolling device and the system can be applied analogously to the method, and vice versa.

[0036] In a first exemplary embodiment, the core element surface, i.e. an outer circumference of the core element, is curved along the axial direction of the rolling device or along its longitudinal direction. The curvature can be convex and / or concave. Also conceivable is a waviness as a function of the position along the longitudinal direction or the axial direction or extension of the rolling device. In an extension of the first embodiment, the core element surface is not convex, concave and / or wavy, but stepped. The gradation can be understood as a waviness with lower resolution. A combination of the features mentioned is also conceivable, for example a core element with a wavy core element surface and a structuring applied thereto.

[0037] In a second embodiment, the core element is hollow and has a relatively thin core wall thickness. The core element can be pumped with a fluid through a fluid opening or evacuated through the fluid opening. Accordingly, a convex or concave core element surface can be adjusted. The disadvantage of this embodiment is that the lateral surface follows the core element surface and is therefore likely no longer cylindrical. However, a significant deviation from the cylindrical shape can be prevented by minor changes to the core element. In particular, the core diameter changes as a function of pressure only in the micrometer or nanometer range.

[0038] In a third embodiment, the core element surface is structured. The core element is preferably produced from a solid shaft and structured by the introduction of full-circumferential grooves, particularly of varying widths. The width, depth, and density of the grooves allow for variation of the pressure and thus the force acting on the embossing element during the subsequent embossing process.

[0039] In a fourth embodiment, it is conceivable for the core element to comprise a plurality of disc-shaped, preferably radially symmetrical core sections which can change their diameter via electronic control. Such core sections are preferably made of piezo materials. Each core section comprises a piezoelectric material and is coated or connected, in particular on an inner and outer ring, to an electrical material which serves as a respective electrode. By applying a voltage between the two electrodes, an electrical field is built up across the piezo material which, due to the piezoelectric field, leads to a radially symmetrical expansion of the core section. This embodiment enables, in particular, a local change in the radius of the core element, which permits the targeted control or regulation of the embossing pressure, i.e. the applied force.

[0040] In a fifth embodiment, it is conceivable for the core element to comprise several disc-shaped, preferably radially symmetrical core sections, which can be individually heated by a heater or cooled by a cooling system. The diameter can also be changed accordingly by applying heat. Such core sections are preferably made of materials with a thermal expansion coefficient that is as linear as possible, allowing for appropriate thermal expansion within the applicable temperature range.

[0041] In a sixth embodiment, it is conceivable for the core element to comprise a plurality of disc-shaped, preferably radially symmetrical core sections, which can be individually evacuated or pressurized with a fluid. The core element would then not be deformed as a whole, but rather only the explicitly controlled core sections would be deformed. Sensors are preferably located in the casing element and / or in the core element and / or in the individual core sections. The sensors are preferably pressure sensors, with the aid of which it can be determined as promptly as possible or in real time whether the desired homogeneous pressure distribution is achieved. Accordingly, a control or regulation system can be used to control or regulate the pressure during application. This has a particularly advantageous effect on achieving the desired spatial distribution of the applied force.It is also conceivable to use temperature sensors or pressure sensors that measure the pressure inside the core or a core element. This allows the externally adjustable parameters to be associated or coupled with the pressure of the pressurization or force applied.

[0042] The shell element can, in principle, be made of any material. However, it has been shown that a polymer formed around a hard core has optimal pressure transfer properties. A metal shell is also conceivable. The core element could be coated with a metal. The resulting rolling device could then be easily machined on a lathe, ensuring a shell surface of high quality and low roughness.

[0043] A ceramic shell, i.e., a shell element that encompasses ceramic or is made entirely of at least one ceramic, would also be conceivable. The core element could be coated with a ceramic, such as an oxide, a nitride, a carbide, and / or boride. Turning such materials proves difficult, as chip formation is unlikely. However, other machining options are promising, which will not be discussed in detail here.

[0044] The rolling device can be used in a system that allows very simple control of the contact between the rolling device and a body to be acted upon, in particular a carrier substrate. The system comprises a base that has the most vibration-damping effect possible. The base has a fixation for the substrate onto which an embossing compound is deposited. Furthermore, the system has a roller carrier, at one end of which the rolling device is fixed to a suspension system. The other end of the roller carrier is not clamped in a fixed bearing or attached to a joint, but is secured against vertical displacement by a floating bearing exclusively against gravity. The floating bearing is preferably a spring element, in particular a leaf spring, which is held in place by a spring element fixation.Between the spring element and the rolling device is a support element which can be moved vertically as a whole by a coarse adjustment element. The support element can also be located between the stamp to be embossed and the end of the roller carrier or right at the end of the roller carrier. On the support element is a fine adjustment element, preferably constructed from at least a bellows and / or a piezo element or a piezo column, as well as a contact element holder with a contact element located therein. The contact element is preferably a ball. A pressure sensor is located in the contact element holder and below the contact element. The coarse adjustment element roughly positions the roller carrier and thus the rolling device. The fine adjustment element allows fine positioning of the roller carrier and the rolling device. The contact element acts as a detector should the roller carrier be lowered too far.The rolling device itself moves within the roller carrier in a movement area S and can apply the corresponding pressure there.

[0045] The diameter of the rolling device is less than 100 mm, preferably less than 80 mm, even more preferably less than 60 mm, most preferably less than 40 mm, and most preferably less than 30 mm. The smaller the diameter of the rolling device, the larger the angle between the tangent to the rolling device and the flat surface of the embossing element. A larger angle improves the air displacement between the rolling device and the embossing element and thus the embossing result. A further advantage of a small diameter is that the amount of electrostatic charge generated, which can arise from contact or frictional electricity during the rolling process, is minimized. The larger the diameter of the rolling device, the larger the area over which charge carriers can be transferred from the rolling device to the embossing element or vice versa.In particular, the length to diameter ratio of the rolling device should be as large as possible.

[0046] In a particularly preferred embodiment of the invention, the rolling device is therefore designed to be earthed in order to be able to dissipate electrostatic charges.

[0047] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. These show:

[0048] Figure 1 shows an embodiment according to the prior art, Figure 2a shows a first exemplary embodiment of a rolling device according to the present invention,

[0049] Figure 2b shows a second exemplary embodiment of a rolling device according to the present invention,

[0050] Figure 2c shows a third exemplary embodiment of a rolling device according to the present invention,

[0051] Figure 2d shows a fourth exemplary embodiment of a rolling device according to the present invention,

[0052] Figure 2e shows a fifth exemplary embodiment of a rolling device according to the present invention,

[0053] Figure 3 shows the third embodiment of a rolling device in use and

[0054] Fig. 4a / 4b an abstract top view of a stamping process in two positions or for two consecutive contact surfaces

[0055] Figure 5 shows a system according to an exemplary embodiment of the present invention.

[0056] In the figures, identical components or components with the same function are identified by the same reference numerals. The figures are not drawn to scale, and hatching has been omitted.

[0057] Figure 1 shows a rolling device 1 from the prior art, consisting of a core element 2 and a shell element 3.

[0058] Figure 2a shows a first preferred embodiment of a rolling device 1 according to the present invention, which comprises a core element 2 and a shell element 3. The core element 2 is a solid body with, in this case, a convex curvature of the core element surface 2o. It is also conceivable that the core element surface 2o is concavely curved or wavy.

[0059] Figure 2b shows a second preferred embodiment of a rolling device 1 according to the present invention, which comprises a core element 2 and a casing element 3. The core element 2 is designed as a hollow body in order to be able to pressurize and / or evacuate a core element interior 4 with a fluid. In the present case, a pressure in the core element interior 4 is increased by a fluid such that the core element surface 2o assumes a convex shape. It is also conceivable for the core element surface 2o to be concavely curved, in particular by applying a vacuum in the core element interior 4. In this embodiment, the casing element surface 3o will also deform accordingly by adapting the core element surface 2o. The core element interior 4 is filled or evacuated with a fluid via a fluid opening 5.The curvature of the shell element surface 3o shown in the figure is not to scale and is shown explicitly only for the sake of clarity. This embodiment is particularly suitable for pressurization, in which increased pressure must be applied in the center of the rolling device 1.

[0060] Figure 2c shows a third preferred embodiment of a rolling device 1, which comprises a core element 2 and a shell element 3. The core element 2 was structured directly from a shaft 7, preferably by milling, even more preferably by turning. The core element 2 comprises a sequence of radially symmetrical grooves 17, obtained in particular directly by calculation or simulation. The width and position of the grooves 17 of this groove sequence are preferably selected such that, when pressure is applied, the line force generated in a contact surface is as homogeneous as possible (see Figure 3 below). In particular, this embodiment represents an elegant way of imitating the pressure behavior of a rolling device 1 according to Figure 2a. Convex rolling devices 1 according to Figure 2a are relatively difficult to form with close tolerances for large ratios of roll length to roll diameter.By structuring the core of the rolling device 1, however, at least the pressure behavior of a rolling device 1 according to Figure 2a can be simulated.

[0061] The next two figures describe rolling devices 1 which can be switched and / or controlled spatially.

[0062] Figure 2d shows a fourth preferred embodiment of a rolling device 1 according to the present invention, which comprises a core element 2 and a casing element 3, wherein the core element 2 is constructed from a plurality of core sections 6, particularly preferably eight individual core sections 6. The core sections 6 are fixed on a shaft 7. The third and sixth core sections 6 from the left have been sectioned on one side in order to be able to illustrate the structure of a single core section 6. A core section 6 comprises at least a first annular electrode 8, a piezoelectric ring 9, and a second annular electrode 8. The first annular electrode 8 rests on the shaft 7. The second annular electrode 8 contacts the casing element 3. The piezoelectric ring 8 is enclosed by the two annular electrodes 8. A voltage can be applied between the two annular electrodes 8 of each core section 6.By applying a voltage U>0 (see sixth core element 6 from the left), the piezoelectric ring 9 expands radially. This results in a core element 2 comprising several switchable core sections 6. The smaller the width of the core sections 6, the higher the resolution along a rotational axis R of the core element 2. Wiring is preferably provided via the shaft 7 and continues along the edge of the shaft 7 in a manner not further specified.

[0063] Figure 2e shows a fifth preferred embodiment of a rolling device 1 of the present invention, which comprises a core element 2 constructed from a plurality of core sections 6, represented by eight individual core sections 6. The core sections 6 are fixed on a shaft 7. The third and sixth core sections 6 from the left have been cut open on one side to illustrate the structure of a core section 6. A core section 6 comprises at least one annular expansion element 15, which can undergo a change in length due to thermal expansion when subjected to thermal stress. The annular expansion element 15 rests on the shaft 7. The annular expansion element 15 contains a heater 16, preferably a simple heating wire, which converts current into Joule heat. A voltage can be applied to the heater 16 to generate the current flow.By applying a voltage U>0 (see sixth core section 6 from the left), the annular expansion element 15 expands radially due to thermal expansion. This results in a core element 2 with multiple switchable core sections 6. The smaller the width of the core sections 6, the higher the resolution along the rotation axis R of the core element 2. The wiring is preferably carried out via the shaft 7 and is continued at the edge of the shaft 7 in an unspecified manner.

[0064] Figure 3 shows the rolling device 1 according to Figure 2c, which transmits a force, in particular a line force, to an embossing element 30, in particular with a stamp 11, wherein the stamp 11 was manufactured on a carrier 10. The carrier 10 is usually referred to in English as a "back-plane". The carrier 10 is preferably made of a transparent material, in particular glass, so that the embossing compound 12, which is embossed by the stamp 11, can be cured from the side of the carrier 10 using UV light. The embossing compound 12 was deposited on a substrate 13 before the embossing process. The lower part of Figure 3 shows a pressure-location diagram. The abscissa represents the position and the ordinate the pressure along a line of the substrate 13. The rolling device 1 is pressed onto the carrier 10 on the left and right sides by the forces F and thus generates a line pressure along the stamp 11 or the embossing mass 12.The print line has a width of less than 10 mm, preferably less than 8 mm, more preferably less than 5 mm, most preferably less than 3 mm, most preferably less than 1 mm.

[0065] Figure 4a shows an abstracted top view of an embossing process or a plan view of an embossing process in a first position according to the present invention. Only the most important components are shown. The embossing element 30 embosses the circular substrate 13 by applying pressure to the rolling device 1. The rolling device 1 is shown semi-transparently in order to be able to show the approximate length L1 of the force applied or the contact area. It can be seen that the length L1 of the line pressure at the beginning of the substrate 13 is much smaller than the diameter of the substrate 13. The left and right forces F acting on the rolling device 1 (see Figure 3) must also be correspondingly small. The force as a function of the translation direction y of the rolling device 1 for the left and right bearings of the rolling device 1 are shown on the left and right sides, respectively.

[0066] Figure 4b shows an abstracted top view of an embossing process or a top view of the embossing process in a second position, wherein in the second position, the rolling device 1 rests against an adjacent contact surface with a greater length, namely L2. The rolling device 1 has been moved along the translation direction y and is located in the center of the substrate 13. Accordingly, the length of the line print on L2 has also increased. Therefore, the control of the line print along the translation direction of the rolling device 1 is preferably force-controlled, and the line print along a normal to the translation direction is geometry-controlled.

[0067] By appropriately designing the core element 2 in conjunction with the correct, in particular adjusted or controlled, force F on the left or right position of the rolling device 1, the homogeneity of the line pressure can be ensured.

[0068] Figure 5 shows an abstract side view of a system 26 with a rolling device 1 according to the invention. The suspension of the rolling device 1 on a roller carrier 21, as well as the components for the translational movement along the translation direction T of the rolling device 1 are not shown. The rolling device 1 can be moved along a range of motion S, in particular along a translation direction T. The rolling device 1 is connected to a spring element 19 via a roller carrier 21. The spring element 19 is fixed by a spring element fixation 20. The roller carrier 21 is supported between the spring element fixation 20 and the rolling device 1, in particular centrally, by a fine adjustment element 25. The fine adjustment element 25 is able to raise or lower the roller carrier 21 and all components fixed thereto with a small travel path. The fine adjustment element 25 is in particular a bellows, a piezo element ora piezo column and can be regulated or controlled by switching elements (not shown). Next to the fine adjustment element 25 there is a contact element 22, in particular a ball. The contact element 22 is mounted in a contact element holder 23. Below the contact element 22 in the contact element holder 23 there is a readable pressure sensor (not shown). The fine adjustment element 25 and the contact element 22 can be positioned together in height by a coarse adjustment element 24. The coarse adjustment element 24 can be a motor with or without a gear, in particular a linear motor. The elements 22, 23, 24 and 25 together form a support element 27. The support element 27 can also be located at the end of the roller carrier 21. The coarse adjustment element 24 ensures that the roller carrier 21 and thus the rolling device 1 can assume their starting position.In particular, this is the position at which the rolling device 1 just barely touches the carrier 10 on which the stamp 11 was created. In this position, the fine adjustment element 25 can then perform the fine positioning. The contact element 22 allows, via the pressure sensor installed in the contact element fixation 23, a measurement of the force exerted by the roller carrier 21 and all of the components fixed to it. The position of the rolling device 1 and the available lever arm can be used to calculate the average pressure applied by the rolling device 1 to the carrier 10 and thus to the stamp 11 and the stamping compound 12 to be stamped with it. The actual pressure distribution, however, is preferably measured by pressure sensors in the rolling device 1. The advantage of this system 26 is its simple implementation and cost-effectiveness.It is also conceivable for the substrate 13 not to rest directly on the base 18, but for a substrate holder to be located between the substrate 13 and the base 18. Sensors, preferably pressure sensors, can also be installed in the base 13 and / or in a substrate holder. Any substrate holder could be temperature-controlled, i.e. heated or cooled, in order to be able to adjust the temperature of the embossing process. In particular, the viscosity of the embossing compound 12 to be embossed can be influenced by increasing the temperature. Peltier elements for heating and / or cooling would be particularly preferred, as they are easy to install and can be controlled electrically particularly easily. Furthermore, temperature control can have a positive influence on the print homogeneity to be achieved.

[0069] Furthermore, the floating bearing design with the aid of a spring 19 allows for a construction in which the bearing does not react on the rolling device 1 and influence the embossing. The roller carrier 21 preferably rests only on the spring element 19 and is pressed downward exclusively by gravity, i.e., a vertical force. The fine adjustment element 25 and the contact element 22 apply the corresponding counterforce. Ideally, this prevents horizontal forces from being generated that would cause the rolling device 1 to slide during the contacting process and thus destroy the embossed pattern.

[0070] List of reference symbols:

[0071] 1 rolling device

[0072] 2 Core element

[0073] 2o core element surface

[0074] 3 Sheath element

[0075] 4 Core element interior

[0076] 5 Fluid opening

[0077] 7 Wave

[0078] 8 Electrode

[0079] 9 Piezoelectric ring

[0080] 10 carriers

[0081] 11 stamps

[0082] 12 Embossing compound

[0083] 13 Substrat

[0084] 14 stamp structures

[0085] 15 Expansion element

[0086] 16 Heating 17 Groove

[0087] 18 Base

[0088] 19 Spring element

[0089] 20 Spring element fixation 21 Roller carrier

[0090] 22 Contact element

[0091] 23 contact element holder

[0092] 24 coarse adjustment element

[0093] 25 Fine adjustment element 26 System

[0094] 27 Support element

[0095] 30 embossed element

[0096] S range of motion

[0097] R rotation axis TT translation direction

[0098] L1 , L2 Length of line print

Claims

Claims 1. A rolling device (1) for applying pressure to an embossing element (30) which, during an embossing process, creates a surface structure in an object, in particular in an embossing compound (12), wherein, during the embossing process, the rolling device (1) acts on the embossing element (30) via a contact surface and moves along a translation direction (T) while rotating about an axis of rotation (R) in order to act on the embossing element (30) via contact surfaces offset from one another along the translation direction (T), in particular one after the other, comprising: a core element (2) and a casing element (3) surrounding the core element (2), wherein the core element (2) and the casing element (3) are designed in such a way that a force acts homogeneously on the embossing element (30) both via the contact surface along a direction running perpendicular to the translation direction (T) and via a plurality of contact surfaces following one another in the translation direction (T).

2. Rolling device (1) according to claim 1, wherein the core element (2) has a circumferential geometry that is completely rotationally symmetrical to the rotation axis (R).

3. Rolling device (1) according to one of the preceding claims, wherein the core element (2) is made of a first material and the shell element (3) is made of a second material, wherein the first material is different from the second material.

4. Rolling device (1) according to one of the preceding claims, wherein the circumferential geometry of the core element (2) is variable.

5. Rolling device (1) according to one of the preceding claims, wherein the circumferential geometry of the core element (2) is adjustable via at least one electrode and / or a piezo element in and / or on the core element (2).

6. Rolling device (1) according to one of the preceding claims, wherein the core element (12) has a core element interior (4) for receiving a fluid.

7. Rolling device (1) according to claim 6, wherein a wall of the core element (2) is elastically deformable.

8. Rolling device (1) according to claim 6 or 7, wherein the rolling device (1) has a connection for fluid communication with the core element channel space (4).

9. Rolling device (1) according to one of the preceding claims, wherein the core element (2) has a circumferential geometry with a curved, for example convex and / or concave, profile extending in the axial direction.

10. Rolling device (1) according to one of the preceding claims, wherein the core element (2) has at least one circumferential groove.

11. Rolling device (1) according to one of the preceding claims, wherein the casing element (3) has a first extension measured in the radial direction, in particular averaged over an axial extension of the rolling device (1), and the core element (2) has a second extension measured in the radial direction, in particular averaged over the axial extension of the rolling device (1), wherein a ratio of the first extension to the second extension assumes a value which is less than 0.2, preferably less than 0.1 and particularly preferably less than 0.

05.

12. System (26) for embedding a surface structure in an object, in particular in an embossing mass (12), by means of a rolling device (1) according to one of the preceding claims and the embossing element (30).

13. System (26) according to claim 12, wherein the embossed element (30) is suitable for realizing a micro- or nanometer structure.

14. System (26) according to claim 12 or 13, wherein the system (26) comprises a roller carrier (21) for the rolling device (1), wherein the roller carrier (21) comprises a means for adjusting the height of the rolling device (1) and / or a signaling device which indicates a maximum position of the rolling device and / or the roller carrier (21), and / or a spring element (19).

15. A method for embedding a surface structure in an object by means of a system according to claim 13 or 14, wherein in an embossing process a surface structure is embedded in an object, in particular in an embossing compound, wherein during the embossing process the rolling device (1) acts on the embossing element (30) via a contact surface and is moved along a translation direction (T) in a rotating manner about an axis of rotation (R) in order to act on the embossing element (30) via contact surfaces offset from one another along the translation direction (T).

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