Imprint Method

Abstract

A roll-to-plate imprinting method for texturing a substrate with a relief structure via a flexible stamp, the stamp being provided with at least one imprint texture. To carry out the method, a resin or lacquer is applied non-uniformly in a non-homogeneous pattern to the substrate or to the flexible stamp or to both. A majority of the resin or lacquer is positioned on the flexible stamp at a leading edge side of at least one imprint texture and / or a majority of the resin or lacquer is positioned on the substrate at a first contact position with said stamp and / or on a leading edge side of at least one active area.

Description

[Technical field]

[0001] The present invention relates generally to an imprinting method in which a texturing or patterning layer is applied to a substrate, also referred to as texturing or patterning the substrate.

[0002] Functional texturing layers on substrates play an important role in many modern technological fields. Clever use of such layers can increase performance, reduce costs or improve product appearance. For example, diffusing layers are used in displays to enable the use of thinner LED backlight concepts and allow displays to be illuminated from the side. Other new emerging possibilities for cutting-edge technology are the integration of functional texturing layers into solar panels to improve their efficiency or into organic light-emitting diode (OLED) lighting panels to extract more light from microlenses for 3D optical applications.

[0003] In texturing, the substrate, the stamp or both are coated with a lacquer (also called resin or resist, the three words being used synonymously throughout this application). After pressing the stamp onto the substrate with the lacquer between them, while the stamp is still in contact with the lacquer, the textured lacquer is cured to a solid phase. This process is typically called the imprinting method. Curing can be performed by using heat or radiation such as visible or ultraviolet light. Typically, texturing processes are classified as roll-to-roll, plate-to-plate or roll-to-plate processes, depending on whether the stamp is pressed onto the substrate by a roller, as in a rotary press, or a plate, as in a clerical stamp, or whether pressure is applied to the substrate by a roller, as in a rotary press, or a plate, as in a lithographic printing process. Roll-to-plate imprinting has already been described in US Pat. No. 4,128,369.

[0004] Typically, roll-to-roll processes are used for imprinting large flexible substrates such as newspaper printing, while plate-to-plate imprinting is typically performed for smaller substrates such as electronic circuit printing.

[0005] Roll-to-plate imprinting is a technique typically used to imprint large rigid substrates such as glass or metal plates used to produce displays, solar cells or other optoelectronic devices. In roll-to-plate imprinting, typically either a textured roller or a flexible stamp is used. In this case, the flexible stamp is not necessarily part of the roller, but is pressed against the substrate by the roller. The advantage of a flexible stamp is that pressure does not have to be applied simultaneously over the entire substrate, but can be applied in a line, and the imprinted texture design can be longer than the circumference of the roller. In roll-to-plate imprinting, typically, the rigid substrate is provided on a conveyor belt or a series of transport rollers and transported under the imprint rollers, optionally with a flexible stamp between them, depending on the embodiment. Before the imprinting process, the substrate or the stamp or both components are coated with an imprintable resin or lacquer, which, when in contact with the substrate or stamp, is textured with a negative imprint of the stamp's texture and is typically cured while in contact with the stamp to properly preserve the imprinted texture of the resin. After curing, the stamp is separated from the imprinted layer of hardened resin or lacquer on the substrate. When the resin or lacquer contacts the stamp and / or substrate during the imprinting process, there is a risk that a significant amount of lacquer will be extruded from the substrate or into undesired locations on the substrate, causing a wide variety of problems. First, the overflowing lacquer will soil the device performing the imprinting process, second, the overflowing lacquer can contaminate the backside of the product, and third, the flow of lacquer between the substrate and the stamp can be uncontrolled and uneven, thus negatively affecting the quality of the imprinted product.This lacquer overflow and entrapment of air between the substrate and the stamp is typically dealt with by modifying the stamp, as described for example in EP 3256907 and EP 3256906. However, the solution proposed there does not solve the problem of contamination of the apparatus by overflowing lacquer, which requires additional cleaning operations and also leads to a waste of lacquer, which is detrimental both to the economy of the imprinting process and to environmental protection. This problem is typically solved by leaving space for a larger overflow area outside the effective area. The effective area is the area of ​​the substrate that is textured or patterned by the imprinting process. Such a larger overflow area outside the effective area increases the waste of substrate material and lacquer, which therefore increases the cost of the process.

[0006] It is therefore an object of the present application to provide a roll-to-plate imprinting method that is more economical and saves resources by reducing the amount of lacquer required.

[0007] The problem is solved by a roll-to-plate imprinting method for texturing a substrate with a relief structure via a flexible stamp with at least one imprint texture, wherein resin or lacquer is applied non-uniformly in a non-homogeneous pattern to the substrate or to the flexible stamp or to both, and a majority of the resin or lacquer is positioned at a leading edge side of at least one imprint texture of the flexible stamp and / or a majority of the resin or lacquer is positioned at a first contact position of the substrate with said stamp and / or at a leading edge side of at least one active area.

[0008] In the context of the present application, the term "mainly" is intended to mean more than 50% of the amount of resin or lacquer, in some embodiments more than 80%. The majority of the resin is positioned at or around the first contact of the substrate with the stamp, or at one or more leading edges of one or more effective areas, i.e. in front of and / or to the sides of one or more effective areas as viewed in the direction of the imprinting method, around the effective areas. Additionally or alternatively, the majority of the resin is positioned at or around the first contact of the stamp with the substrate, or at or around the leading edge of the imprint texture of the stamp. The positioning of the resin is performed before the imprinting method. The effective area of ​​the substrate is the location where the resin is imprinted to form the relief structure. It should be noted that there may be several effective areas on one substrate, for example, when multiple products are placed on one stamp. For large substrates, the pattern in which the resin is placed on the substrate and / or on the flexible stamp may be repetitive, if it is repeated in different effective areas.

[0009] The roll-to-plate imprinting method according to the present application is an imprinting method in which a roller applies pressure to the imprint texture to be imprinted on a separate plate-like substrate, and the substrate moves relative to the roller. In roll-to-plate imprinting, pressure is not applied simultaneously to the entire substrate, but to a linear area perpendicular to the direction in which the substrate moves relative to the roller. The direction in which the substrate moves relative to the roller is referred to throughout this application as the "direction of the imprinting method" or "imprint direction". The presence of an imprint direction is an important feature that distinguishes roll-to-plate (and roll-to-roll) imprinting methods from plate-to-plate imprinting methods in which pressure is applied simultaneously to the entire effective area as in conventional lithographic presses. In alternative plate-to-plate processes, pressure increases in a ring-like manner from the inside to the outside. Thus, while the plate-to-plate process does not have a unidirectional imprinting direction, the roll-to-roll imprinting method and the roll-to-plate imprinting method have a unidirectional imprinting direction that is the direction of the imprinting method.

[0010] Unlike continuous roll-to-roll processes, roll-to-plate processes typically imprint individual panels with beginning and ending near or at the edge of individual substrates. Thus, effects on beginning and ending, such as resin spillage due to resin overflow, are potentially present on each substrate, not only on the edge of a very long web of substrate that can be cut and discarded with negligible impact on the process economics, as in roll-to-roll imprinting. Therefore, to achieve consistent high quality imprints, resin overflow must be precisely controlled to avoid it in this roll-to-plate process.

[0011] Throughout this application, texturing refers to the process of providing a substrate having a smooth surface with a three-dimensional structure that, when viewed from above, appears as a relief of valleys and peaks, or openings or recesses and protrusions, of varying height, depth, and size. In one embodiment, texturing may refer to providing a three-dimensional structure in a resin layer of a substrate.

[0012] According to the present application, a stamp is any means that can be used to transfer the negative of a texture, for example to the surface of a resin layer, for this purpose the stamp has a three-dimensional texture, hereinafter referred to as "imprint texture". The imprint texture typically consists of openings or recesses and protrusions, the stamp may have a non-adhesive feature that allows easy removal of the stamp from the hardened resin. The stamp works according to two basic principles. The first is the principle of relief imprinting, in which the stamp is wetted only in the height of the stamp with any kind of imprint medium, such as ink, wax, resin or lacquer. After wetting with the imprint medium, the stamp is pressed against the substrate, the stamp leaving an image of the protrusions of the stamp. In relief imprinting, which is the working principle of a normal clerical stamp for example, only the protrusions are wetted with the imprint medium, the openings or recesses have the purpose of separating the protrusions from each other. The second is the principle of intaglio imprinting, in which the stamp is wetted with the imprint medium and then, using a cleaner or doctor blade, the imprint medium remains only in the openings, while the protrusions are free of the imprint medium. The stamp is then pressed against the substrate, leaving behind an image of the openings of the stamp, formed as protrusions in the resin or on the substrate that completely or partially displace the resin. The stamp may also be a thin metal sheet, a thin glass sheet or a combination of one or more foils and / or metal sheets and / or glass sheets. In intaglio imprinting, the purpose of the protrusions is therefore to separate the openings from one another. The principle of intaglio imprinting can also be used for the texturing of an imprint medium already present in the substrate, such as a lacquer or an imprinting resin. In such a case, the protrusions of the stamp are transferred to the openings of the substrate and the openings of the stamp are transferred to the protrusions of the substrate. This is known from the mode of operation of conventional seal matrices, which are used to texturize spots of molten wax. The stamp may be rigid or flexible.According to the present application, the flexible stamp is a stamp with a Young's modulus of up to 10 gigapascals (GPa). The flexible stamp of the pending application may be, for example, but not limited to, a plastic foil such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polycarbonate (PC). The flexible stamp may be a metal sheet, a glass sheet, any other sheet or combination or laminate of materials. The foil or sheet may itself be textured, or the foil or sheet may serve as a support for an imprint texture composed of a separate layer or layers. In an embodiment, the imprint texture may include a polymer containing monomeric, oligomeric, or polymeric components such as epoxides, thiols, polyvinyl resins, acrylates, methacrylates, polyethers, vinyl ethers, urethane acrylates, polyesters, fluorinated acrylates, fluorinated methacrylates, fluorinated polyethers, siloxanes, siloxane acrylates, or mixtures thereof. The imprint texture may have an inherent non-adhesive property. The non-stick properties can be achieved by additives to the material to reduce the surface free energy, or by an appropriate combination of low surface free energy materials (e.g., perfluoropolyether (PFPE) monomers, perfluorinated monomers, silicone monomers, and / or aliphatic monomers, among others), or by surface treatments such as non-stick coatings.

[0013] The imprint medium according to the pending application may be a lacquer or a resin. Typical imprint media used in the pending application are curable resins or lacquers that are liquid or viscous when applied to a substrate or in contact with a flexible stamp and can be cured by exposure to heat or radiation such as ultraviolet light. When curing using radiation, the stamp or substrate or both must be transparent to said radiation. In one embodiment, the imprint medium may be a polymer that includes monomeric, oligomeric, or polymeric components such as epoxides, thiols, polyvinyl resins, acrylates, methacrylates, polyethers, vinyl ethers, urethane acrylates, polyesters, fluorinated acrylates, fluorinated methacrylates, fluorinated polyethers, siloxanes, siloxane acrylates, or mixtures thereof. In one embodiment, the resin may include an agent for initiating the curing, such as a radical initiator, a cationic initiator, or an anionic initiator. Suitable initiators are well known to those skilled in the art. Possible radical initiators are azo compounds such as azobisisobutyronitrile, peroxides such as dibenzoyl peroxide or peroxodisulfates, phosphine oxides such as diphenylphosphine oxide, aromatic ketones such as 1-hydroxy-cyclohexylphenyl-ketone or 2-hydroxy-2-methylpropiophenone, or Norrish type II initiators such as methylbenzoyl formate. Possible cationic and anionic initiators are benzenesulfonate esters, alkylsulfonium salts, or photobase generators such as triphenylsulfonium (cationic), tetrafluoroborate or 2-nitrobenzylcyclohexylcarbamate (anionic).

[0014] Throughout this application, the term "uneven" means that the amount of a substance, such as a resin or lacquer, applied to a surface is not the same on all parts of the surface, but rather there is a gradient in the amount of the substance on the surface or the substance is simply not evenly distributed on the surface. In one embodiment, said gradient is oriented parallel to the imprint direction, anti-parallel to the imprint direction, perpendicular to the imprint direction, or at any angle between -90° and +90° to the imprint direction. According to the mathematical definition of a gradient, the direction of the gradient is the direction of decreasing amount. In one embodiment, "uneven" means that more than 50% of the resin or lacquer is located on half of the effective area of ​​the substrate and / or half of the imprint texture of the flexible stamp. In one embodiment, "uneven" means that more than 70% of the resin or lacquer is located on half of the effective area of ​​the substrate and / or half of the imprint texture of the flexible stamp. In one embodiment, "uneven" means that more than 85% of the resin or lacquer is located on half of the effective area of ​​the substrate and / or half of the imprint texture of the flexible stamp. In an embodiment, said half of the active area of ​​the substrate containing resin and / or said half of the imprint texture of the flexible stamp may be the front half as seen in the direction of the imprinting method. An example of a non-uniform layer is a layer of resin that increases or decreases in thickness in the imprinting direction, or a substrate with a specific pattern of resin. Non-uniform may mean that some parts of the substrate are free of resin, while other parts of the substrate are free of resin.

[0015] The term "inhomogeneous" means that the substance, such as resin or lacquer, applied to the surface is not distributed homogeneously over the entire surface and that the pattern is not the same in all parts of the surface, i.e., the pattern is not repeated over the entire surface. An example of an inhomogeneous pattern according to this definition is a comb-like pattern formed by the resin or lacquer on the surface or a pattern of a shape similar to a single letter, such as "E", "M", "W". A typical feature of an inhomogeneous pattern is that it includes both areas where the surface is covered with resin or lacquer and areas where the surface is not covered with resin or lacquer. Furthermore, an inhomogeneous pattern typically does not repeat within or around the surface of a single effective area. It can be repeated to provide multiple effective areas on one larger imprint surface. The resin or lacquer may be applied to the substrate in the form of a closed line or closed area (e.g., oval, rectangular, or any area shape) or as a dotted pattern, for example of droplets. Furthermore, it is not necessary to cover the entire surface of the substrate or stamp with resin or lacquer.

[0016] A closed layer according to the present application is a layer in which the entire surface of the substrate or stamp, or at least the entire active area of ​​the substrate or the entire textured area of ​​the stamp, is covered with resin or lacquer.

[0017] A heterogeneous pattern may include one or more sub-patterns where the sub-patterns are separated from each other, such as several comb-like patterns, patterns shaped like a single letter such as "E", "M", "W" or the number "3", etc.

[0018] The substrate according to the present application is a plate-like body, i.e. a body whose length and width are both at least four times greater than its thickness. The substrate according to this application is rigid, meaning that it has a Young's modulus of at least 0.5 GPa. The substrate may be any material that meets the rigidity criteria, for example a polymer sheet of polymethylmethacrylate (PMMA) or polycarbonate, glass, metal such as copper, steel or aluminum, or ceramic, or a composite material, or a laminate made therefrom. The substrate used in the method according to the present application is typically an individual substrate. The substrate used in the method according to the present application may comprise several individual substrates that can be connected, such as by being glued together or placed in a suitable frame or in a suitable tray or carrier, before being subjected to the method, so that they can be subjected to the method as one unit.

[0019] The substrate according to the present application has an active area, which is the area that is imprinted during the imprinting method. Typically, the active area is located near the center of the substrate and is thus separated or even spaced from the edge of the substrate by an area that is not part of the active area (hereinafter referred to as "non-active area"). The non-active area allows a smooth start of the imprinting method and serves as a blocking area for excess amounts of resin, so that the overflow of resin does not contaminate the edge of the substrate or the flexible stamp or roller. The size of the non-active area varies (typically from a few hundred microns to several centimeters or more). The active area of ​​the substrate may have the same surface area as the imprint texture of the flexible stamp, but may also have a different surface area.

[0020] A pattern according to the present application is any kind of distribution of resin or lacquer of the substrate and / or flexible stamp, including both areas covered with resin or lacquer and areas not covered with resin or lacquer. The pattern does not have to have an aesthetic or schematic meaning to be called a pattern. However, the pattern may be a regular pattern, meaning a clearly reproducible distribution of different substrate and / or flexible stamp resins, such as, for example, a comb shape, a shape of one or more straight, bent and / or crossed lines, or an inverted shape of the letter "E" or a similar shape. The pattern may be, for example, a random distribution of randomly oriented lines equivalent to a plate of spaghetti or a distribution of randomly located and / or randomly sized droplets. A pattern consisting of several or many droplets may be randomly located and / or randomly sized and may include all or part of regularly spaced droplets.

[0021] Furthermore, the pattern may be a continuous pattern, where the resin or lacquer coated areas are connected to each other, or a discontinuous pattern, where the lacquer and / or resin coated areas are separated from each other and thus have the properties of islands within the areas not coated with resin or lacquer.

[0022] The pattern may be located in the covering area of ​​the flexible stamp and / or the substrate. It is important to note that the covering area does not have to be the same as the imprint texture of the flexible stamp or the active area of ​​the substrate. However, the covering area may be located completely or partially within the active area of ​​the substrate and / or the imprint texture of the flexible stamp. The covering area may be located completely or partially outside the imprint texture of the flexible stamp and / or the active area of ​​the substrate. In such a case, the covering area is located mainly in front of the active area and / or the imprint texture as viewed from the imprint direction. In one embodiment, the covering area is less than 50% of the surface area of ​​the active area. In one embodiment, the covering area is less than 30% of the active area. It is noted that the covering area may be located completely outside, partially outside, or completely inside the active area of ​​the substrate and / or the imprint texture of the flexible stamp. It is noted that the covering area is not only the area covered with the resin or lacquer, but the area bounded by the envelope of all the areas covered with the resin or lacquer. Thus, the coated areas include all areas that are coated with resin or lacquer, but also areas that are not coated with resin or lacquer.

[0023] When starting the imprint method with a new substrate, the leading edge of the flexible stamp and the leading edge of the substrate come into contact with each other. The leading edge of the flexible stamp may be part of the imprint texture or may be located in front of the imprint texture as viewed in the direction of the imprint method. The leading edge of the substrate may be part of the effective area or may be located in front of the effective area as viewed in the direction of the imprint method. The leading edges of the substrate and / or the flexible stamp are part of the covered area or are located in front of the covered area as viewed in the direction of the imprint method. After the leading edges of the flexible stamp and the substrate come into contact with each other, the imprint method proceeds in the imprint direction and the contact area between the flexible stamp and the substrate also proceeds in the imprint direction. During the proceeding in the imprint direction, the resin or lacquer is distributed or redistributed in the effective area in the imprint direction by spreading the inhomogeneous pattern of the resin or lacquer and by forming a resin or lacquer front moving in the imprint direction. The dispensing of the resin or lacquer is carried out in a continuous process before or at the same time as the imprint texture is transferred to the resin or lacquer by the flexible stamp in the active area. A continuous process according to the present application is a process in which there is no clear distinction between two different process steps, such as dispensing the lacquer and transferring the imprint texture to the lacquer. This means, for example, that the dispensing part of the flexible stamp dispenses the resin or lacquer on the surface in the direction of the imprint method, while the imprinting part of the flexible stamp simultaneously transfers a part of the imprint texture to the dispensed lacquer, so that there is no clear distinction between the dispensing part and the imprinting part. Thus, upon contact between the flexible stamp and the substrate, the inhomogeneous pattern of the resin or lacquer of the stamp and / or the substrate is transferred to the imprint layer of the resin or lacquer textured in the active area.

[0024] In one embodiment, the resin or lacquer covers at least 40% of the surface area of ​​the substrate after the imprinting process. In one embodiment, the resin or lacquer covers at least 50%, 60%, 80% or 90% of the surface area of ​​the substrate after the imprinting process. This prevents resin smearing and overflow during the imprinting process.

[0025] The key factors for controlling the distribution or redistribution of the resin or lacquer during imprinting are the size of the gap between the flexible stamp and the substrate and the pressure at which the flexible stamp and the substrate are contacted: the smaller the gap or the higher the pressure, the more the resin or lacquer spreads when it comes into contact with the flexible stamp.

[0026] In one embodiment, the dispensed resin or lacquer covers at least two separate regions of the effective area of ​​the substrate, which are separated from each other by an area that is not covered by resin or lacquer, meaning that the resin or lacquer forms at least two islands in the effective area of ​​the substrate.

[0027] In a further embodiment, the two or more islands of resin remain separated after imprinting and curing of the resin, replicating two or more separated active areas on one or more substrates.

[0028] In one embodiment, after the imprinting method the substrate has at least one open area free of resin or lacquer, said open area being located outside the active area.

[0029] The present application further relates to an imprinted substrate obtainable according to the method according to the present application.

[0030] The present application further relates to an apparatus for carrying out the roll-to-plate imprinting method according to the present application.

[0031] The apparatus according to the present application comprises at least one application device of resin or lacquer, the at least one application device comprising at least one reservoir of resin or lacquer, at least one dispensing means for applying the resin or lacquer and at least one monitoring and control device, the at least one application device being movably arranged at least in the coating area of ​​the substrate or the coating area of ​​the flexible stamp, the dispensing means being able to apply the resin or lacquer to the coating area in a predetermined pattern while the control device controls the application of the resin or lacquer.

[0032] The resin or lacquer applicator may comprise at least one dispenser, at least one kiss roll, at least one spray head and / or at least one stamp as dispensing means. At least one of said dispensing means is movably arranged in any process known to the skilled person, for example on the arm of a robot, such as a delta robot, on a movable stage, on a rail or a combination thereof. As an example, the lacquer applicator may operate according to the same principle as an inkjet printer, which dispenses ink droplets on a substrate conveyed under a print head movable in a direction perpendicular to the paper conveying direction.

[0033] The apparatus according to the present application further comprises a monitoring and control device capable of controlling the amount and / or position of the resin or lacquer before and after imprinting. The monitoring and control device can monitor and control the amount and / or position of the resin or lacquer by weight, distance between the stamp and the substrate, pressure, optically or by other types of electromagnetic radiation such as microwave, infrared or UV light. Thus, the monitoring and control device can be a camera, an infrared sensor, a weighing scale, a microwave detector, a laser unit or any combination thereof. The monitoring and control device can be part of a feedback loop together with the resin or lacquer application device such that the application process of the resin or lacquer is monitored and controlled by the monitoring and control device. As part of said feedback loop, the distance between the flexible stamp and the substrate, the pressure and the imprint speed can be controlled, the distance depending on the desired distribution of the resin or lacquer in the application area. [Brief description of the drawings]

[0034]

Figure 1

Figure 2a

Figure 2b

Figure 2c

Figure 2d

Figure 2e

Figure 2f

Figure 3a

Figure 3b

Figure 3c

Figure 4a

Figure 4b

[0035] Figure 1 shows a schematic of the roll-to-plate imprinting method. A flexible stamp 100 with openings and protrusions 100B is pressed using a roller 101 into resin 102 present on a substrate 104. A unidirectional imprint direction results in the formation of a resin front 102B, as indicated by the arrow. The substrate has a leading edge 104A and a trailing edge 104B that are determined by the imprint direction. A detector 105 can monitor the flow of resin and / or the amount of resin and / or the position of the resin.

[0036] FIG. 2 shows various patterns 202 deposited on the substrate 104 before (FIG. 2a, FIG. 2c, FIG. 2e) and after (FIG. 2b, FIG. 2d, FIG. 2f) imprinting. On the substrate, there is a preferred imprint area 201. This is the location where the effective area will be located after imprinting, and is therefore also called the effective area 201. By imprinting, the resin spreads due to the contact between the flexible stamp and the substrate, forming a resin layer 203. The shape of the resin layer 203 after the roll-to-plate imprinting method depends on the pattern 202 and the imprint settings, and can thus be controlled by a control loop. In FIG. 2a, the pattern 202 is a continuous line and is located inside the effective area 201. In FIG. 2c, the pattern 202 is formed by discontinuous lines and droplets outside the effective area 201. In FIG. 2e, the pattern 202 is two islands of resin that are partly inside the effective area 201 and partly outside the effective area 201. For each of the patterns 202, more than 50% of the amount of resin is located in the front half of the effective area 201A, which is located on the front side of the substrate 104A, and less than 50% is located in the rear half of the effective area 201B. In Fig. 2a and Fig. 2e, the patterns 202 are 100% located in the front half of the effective area 201A. In Fig. 2c, the patterns 202 extend to the rear area of ​​the effective area 201B. However, the majority of the amount of resin (at least more than 50%) is located in the front half of the effective area. The front and rear sides are determined by the imprint direction, which is indicated by the arrow. Fig. 2f shows the situation after the imprint method, where two separate effective areas 201 are imprinted with two separate resin layers 203.

[0037] FIG. 3 shows the distribution of a pattern with resin droplets in a closed layer of resin or lacquer on the substrate surface after imprinting. In FIG. 3a) a pattern 301 on the surface 104 is shown. In one embodiment, the droplet size within a row may vary, preferably the droplet size is smaller closer to the trailing edge. In further embodiments, the droplets may be random or irregular in position and size. FIG. 3b) shows a closed layer 302 of resin or lacquer formed from the resin droplets 301 on the surface 104 by contact with the flexible stamp with higher pressure. FIG. 3c) shows a closed layer 303 of resin or lacquer formed from the pattern 301 on the surface 104 by contact with the flexible stamp with even higher pressure. The closed layer 303 is significantly larger than the closed layer 302. The imprint direction is indicated by the arrow.

[0038] Figure 4 shows the distribution of a discontinuous pattern on a surface 104 using a pattern with droplets and lines. In figure 4a) a discontinuous pattern of resin or lacquer 401 is shown. Figure 4b) shows a closed layer of resin or lacquer 402 obtained by contacting the discontinuous pattern 201 with a flexible stamp in a roll-to-plate imprinting method.

Claims

1. A roll-to-plate imprinting method for texturing a substrate with a relief structure via a flexible stamp having at least one imprint texture, wherein resin or lacquer is applied non-uniformly in a non-homogeneous pattern to the substrate or the flexible stamp or both, and a majority of the resin or lacquer is positioned on a leading edge side of the at least one imprint texture on the flexible stamp and / or a majority of the resin or lacquer is positioned on the substrate at a position of initial contact with the stamp and / or on the leading edge side of at least one effective area.

2. 2. The roll-to-plate imprinting method of claim 1, wherein the resin is applied to a coating area before imprinting, the surface area of ​​the coating area being less than 50%, preferably less than 30%, of the surface area of ​​the substrate.

3. The roll-to-plate imprinting method according to claim 1 or 2, wherein the covering area is part of the effective area and / or the covering area is positioned outside or partially outside the effective area.

4. The roll-to-plate imprinting method according to claim 1 or 2, wherein the pattern comprises droplets and / or consists of one or more closed lines.

5. The roll-to-plate imprinting method according to claim 1 or 2, wherein the pattern is a discontinuous pattern.

6. The roll-to-plate imprinting method according to claim 1 or 2, wherein the pattern comprises at least partly a random distribution of resin.

7. 3. The roll-to-plate imprinting method according to claim 1, wherein in a continuous imprinting method, the resin or lacquer is distributed over the effective area before or at the same time as an imprint texture is imprinted into the resin or lacquer of the effective area.

8. 3. The roll-to-plate imprinting method according to claim 1, wherein the dispensed resin or lacquer covers at least 70% of the surface area of ​​the substrate after imprinting.

9. The roll-to-plate imprinting method according to claim 1 or 2, wherein the substrate has at least one open area that does not contain resin or lacquer after the imprinting method.

10. 3. The roll-to-plate imprinting method according to claim 1, wherein the dispensed resin or lacquer covers at least two distinct areas of the substrate, the two distinct areas being separated from each other by an area that remains uncovered by resin or lacquer after imprinting and curing of the resin or lacquer, thereby providing two or more distinct effective areas on the substrate.

11. An imprinted substrate obtainable by the method of claim 1 or 2.

12. 3. An apparatus for a roll-to-plate imprint method according to claim 1, comprising at least one applicator of resin or lacquer, the at least one applicator comprising at least one reservoir of resin or lacquer, at least one dispensing means for applying the resin or lacquer, and at least one monitoring and control device, the at least one dispensing means being movably arranged to apply resin to at least a coating area of ​​the substrate, the dispensing means being capable of applying the resin or lacquer to the coating area in a predetermined pattern while the control device controls the application of the resin or lacquer.

13. The apparatus according to claim 12 , wherein the monitoring and control device monitors and controls the weight value and / or the distance value between the stamp and the substrate, the pressure value and / or the imprint speed value and / or the position of the resin during the imprint method.

14. The apparatus of claim 13, wherein the monitoring and control device adjusts the volume of the applied resin and / or the distance and / or pressure between the flexible stamp and the substrate and / or the imprint speed, the adjustments depending on the desired distribution of the resin or lacquer in the applied area after imprinting.

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