Imprinting stamp and method

Abstract

The present invention relates to an imprinting stamp and a corresponding method for producing imprinted substrates with variable depth patterns, in particular by using the stamp according to the present invention. The present invention allows for the provision of imprinted products with variable depth patterns due to the use of a stamp comprising at least one textured region and at least one barrier adjacent to at least a portion of the textured region.

Description

[Technical Field]

[0001] The present invention relates to a stamp for imprinting, in particular for nanoimprinting. The present invention further relates to an imprinting method, in particular to a method for producing an imprinted substrate with a variable depth pattern. The present invention also relates to an imprinted product. [Background technology]

[0002] Micrometer- and nanometer-scale textures have gained significant interest and importance over the past few decades. In particular, in optical applications such as displays and solar cells, textures with optical effects, including microlenses and nanolenses, play an important role in improving performance.

[0003] Typically, textures with optical effects are created by covering a substrate, such as a display panel or glass panel, with lacquer or resin, applying the texture to the lacquer using a mold or stamp, solidifying the lacquer or resin while it is in contact with the stamp or mold, for example, using heat, radiation, or other conditions, and then removing the stamp or mold from the solidified resin layer. The process of creating a texture on a surface is typically called a texturing process or an imprinting process; both terms are used synonymously here. Depending on the size and characteristics of the substrate and stamp, a distinction is typically made between roll-to-roll, roll-to-plate, and plate-to-plate processes. In the roll-to-roll process, a long web of substrate, such as foil, fabric, or thin sheet metal, is processed by a textured roller or a stamp pressed against the web by a roller.

[0004] Typically, roll-to-roll processes are performed continuously. In the plate-to-plate process, rigid, individual substrates are textured by individual stamps mounted on a rigid chuck. Typical substrates textured in the plate-to-plate process are semiconductor wafers, such as silicon. For this reason, the plate-to-plate process is also called a "wafer-scale process." In the plate-to-plate process, the size of both the substrate and the stamp is extremely limited, due to the discontinuous structure. In the roll-to-plate process, a rigid, plate-like substrate is textured by a textured ring roller or stamp, which can be a flexible stamp or a rigid stamp pressed against the substrate using a roller. Similar to the plate-to-plate process, discontinuous or individual rigid substrates can be textured using the roll-to-plate process, but the size limitations of the plate-to-plate process do not apply. Thus, the roll-to-plate process enables the texturing of large, rigid material panels, such as plates for photovoltaic modules, smart windows, displays, or other products.

[0005] A typical feature of roll-to-plate and roll-to-roll processes is that, in contrast to plate-to-plate processes, the pressure is not applied uniformly across the surface to be textured, but rather in a moving manner, with the line pressure following the movement of the imprint roller. Due to the movement of the roller relative to the flexible stamp or substrate typically used in roll-to-plate imprint processes, excess lacquer or resin can be fed against the imprint direction, pushed aside, or even fed backward. The amount of excess lacquer that is fed, and the amount that may spill over from the designated imprint area, depends on several characteristics, including, among others, surface height variations between substrates (caused by substrate irregularities or thickness variations), thickness variations of the resin layer (due to variations in the coating process or variations in the rheological properties of the lacquer itself), defects and / or height variations in the flexible stamp or mold, and / or the pressure of the roller (imprint force).

[0006] With near-zero pressure (force), the lacquer excess is not extruded, but the texture replication is also insufficient because the texture is not completely filled with lacquer. If not enough lacquer is used, the final imprint will be partial; the texture will not be fully replicated, or parts of the substrate will not have any texture at all. Using excess lacquer can result in lacquer overflow at the beginning, sides, and end of the imprint area. This can result in the sides of the panel losing functionality or becoming less visually appealing. Furthermore, the overflow area requires additional space on the substrate. Therefore, controlling resin overflow is of utmost importance in the roll-to-plate process.

[0007] A non-limiting example of a functional texture is, for example, the imprinting of lenses into a product, which can improve the visual experience. Images can be rendered more clearly or viewed with a 3D effect. However, sometimes these options need to be switchable. At some times, viewing in standard view is preferable, while in other situations, viewing with adjusted optics is preferred. In other words, the optical effect needs to be switchable. The switchable effect is achieved using a transparent conductive layer, e.g., an indium tin oxide (ITO) layer, an optical layer, and liquid crystals with a switchable refractive index. In this design, an imprint layer with an optical texture is placed between the conductive layer and the liquid crystal. Adjacent to or surrounding the transparent conductive layer, a contact area made of a conductive material, which is not necessarily transparent, may be placed.

[0008] The entire assembly of the transparent conductive layer and the conductive material may be partially or completely surrounded by a sealing region formed, for example, of a non-conductive material. The sealing region may be covered by a seal. This seal may be, for example, an adhesive material such as a UV-cured epoxy resin. Preferably, this seal has low permeability to air and / or water, such as an adhesive containing a water-absorbing agent, also known as a scavenger or getter. This design presents practical challenges. The transparent conductive layer needs to be in contact with a power source. The imprint layer will cover the conductive material in the contact area, limiting the contact.

[0009] Furthermore, the imprint layer is relatively thick. Cured acrylate resins are typically permeable to water over longer timescales. Thus, a thick acrylate layer on the seal can act as a permanent gateway for moderate amounts of moisture, potentially limiting the device's lifetime. Thus, the resin layer between the seal and a potential overseal needs to be as thin as possible to minimize moisture migration paths. Furthermore, when the seal is placed on a textured surface, the seal increases the total thickness of the device, resulting in a thicker overall device.

[0010] Furthermore, controlling the dosage and thickness of the seal placed on the texture with varying heights is complicated. The standard solution to this problem is to remove the texture at the contact and seal locations, reducing the impact of the seal thickness and effectively thinning and flattening the display, eliminating potential water leakage paths. This can be done mechanically, by ablation, by using solvents, or by etching, among others. However, this additional step is costly and can contaminate the device, as particles, fumes, or etching chemicals can smear the device's functional areas. Summary of the Invention [Problem to be solved by the invention]

[0011] It is thus an object of the present invention to provide a solution to the above-mentioned drawbacks, or at least to provide an alternative means for the production of functional textured layers or devices. [Means for solving the problem]

[0012] The present invention provides an imprinting stamp, in particular a nanoimprinting stamp, which comprises: At least one texture region; at least one barrier adjacent to at least a portion of the at least one textured region; at least one barrier extends in particular over at least the length of at least one side of the textured region, In particular, at least a portion of the at least one barrier has a substantially uniform height that is higher than the highest peak of the at least one textured region.

[0013] The stamp according to the invention is particularly suitable for texturing a resin layer on a substrate and allows the production of textured products or substrates having a textured area at least partially adjacent to and / or surrounded by at least one contact surface, wherein the maximum residual layer thickness of the at least one contact surface is smaller than the maximum residual layer thickness of the imprinted textured area.

[0014] Having at least one barrier with a substantially uniform height above the highest peak of the at least one textured region allows the barrier to form, during imprinting, a substantially uniform region with a relatively thin thickness that can function as a contact surface. Such a contact surface can be used, for example, to provide electrical and / or thermal contact, to accommodate electronic elements, and / or for sealing purposes. Due to the effective configuration of the stamp, the use of additional processing steps to form the contact surface, such as etching, mechanical removal, or ablation, can be omitted.

[0015] In particular, the use of a barrier according to the invention contributes to achieving this result. The invention, and in particular the stamp and / or method according to the invention, allows the production of imprinted products with substantially uniform areas having a thickness of 5 μm or less. Such areas can function as contact surfaces.

[0016] The stamp according to the present invention is particularly adapted for use in the method according to the present invention. The textured area of the stamp typically comprises depressions and protrusions. The depressions and protrusions can be adapted to create a volume for receiving at least a portion of the resin or lacquer (coating). The stamp can, for example, be a substantially flexible stamp. However, it is also conceivable that the stamp can be a substantially rigid stamp and / or that the stamp can be formed by a roller, in particular a textured roller.

[0017] Possibly, the stamp according to the present application includes a textured layer with openings and ridges forming a texture on a first side of the textured layer, while a second side of the textured layer may be fixed to a carrier, such as, for example, a handle robot arm, a roller, a metal or glass sheet, or a carrier foil. When a carrier foil is used, the entire stamp, including the carrier, is essentially a two-dimensional sheet-like structure. Stamps of this shape may be referred to throughout this application as "flexible stamps" or simply "flex stamps." In flexible stamps, the carrier may include multiple layers. At least one of the layers should be a resin layer, but the carrier may also include a reinforcing material, such as, for example, a thin, bendable glass sheet.

[0018] In one embodiment, the texture layer of the stamp is not fixed to a carrier, and the stamp consists of only the texture layer. Again, the stamp may be flexible. The texture layer of the stamp may be of any material known to those skilled in the art, such as metal, quartz, silicon, glass, or a polymer, such as an elastomeric resin, such as an acrylate resin, an epoxy resin, or rubber.

[0019] The stamps according to the present application may, for example, transfer ink, resin, or lacquer to a surface to produce an imprint pattern on the exterior surface, similar to the working principle of an office stamp. In this mode of operation, the textured layer or raised areas of the stamp are moistened with ink, lacquer, or resin and then pressed against a target surface so that the portions of the stamp moistened with ink or resin are visible on the target surface. This principle is known as relief imprinting.

[0020] The stamp may also be brought into contact with a liquid, molten, or viscous material on or above the stamp, so that the liquid, molten, or viscous material conforms to the stamp's texture and hardens while in contact with the stamp, for example, by heating, cooling, or by electromagnetic radiation. When the stamp is removed, a negative image of the stamp is formed in the hardened material, which is textured like spots of molten wax on a document with a conventional sealing matrix. This imprinting principle is known as intaglio imprinting.

[0021] The depressions and protrusions of the stamp can thus form either a positive or a negative image of the texture produced by the stamp, depending on the imprinting principle, whether relief or intaglio imprinting is used. The height of the protrusions and the depth of the recesses are not particularly limited, but neither the height of the protrusions nor the depth of the recesses should adversely affect the ease of handling and mechanical stability of the stamp.

[0022] Mechanical stability is most important when there is no carrier to stabilize the texture layer of the stamp. In this case, the thickness of the texture layer must be large enough to avoid forming a predetermined fracture point in the texture layer, especially if the texture layer is exposed to tension during the imprinting or texturing process.

[0023] When the stamp is used as a flexible stamp, ease of handling is important. For flexible stamps, folding characteristics are important, and the height of the ridges relative to the rest of the stamp's textured layer must not adversely affect the flexibility of the stamp. Depending on the imprinting technique used, different ridges may have different heights and / or different recesses may have different depths.

[0024] The stamp according to the present application may be provided with ridges in its blank areas, whose height and / or size allow the formation of a resin layer up to 5 microns thick. These ridges may form barriers in the context of the present invention. For simplicity's sake, these ridges will be referred to as "extended ridges" below. They are located in the blank areas. They may also be located adjacent to the active areas. In one embodiment, the extended ridges form a kind of frame around part of or the entire active area. Thus, embodiments can be envisaged in which at least one barrier forms a frame around part of at least one textured area, or the frame may completely surround the textured area.

[0025] In a possible embodiment, at least one barrier substantially surrounds at least one textured region. At least one barrier may surround the textured region. The barrier may possibly be positioned at a predetermined distance from the textured region, for example, at a distance of at least 0.5 μm. Preferably, the height of the barrier is substantially uniform throughout the barrier. At least one barrier defines a width and a height, and the height of at least one barrier is substantially uniform and / or the width of the barrier is substantially uniform. A substantially uniform barrier can actively contribute to providing a uniform and / or consistent contact surface in the resulting product. It is conceivable that at least one barrier has a substantially uniform width and / or height throughout the entire length of the barrier.

[0026] At least one barrier is preferably a continuous barrier. It is conceivable that at least one barrier is an uninterrupted barrier. Thus, in a possible embodiment, at least one barrier is a continuous barrier that completely surrounds the textured area. The use of a continuous barrier also positively contributes to achieving a consistent and well-defined product, since it prevents the presence of undesirable resist residues that could adversely affect the product. A consistent contact surface results in a more consistent and reliable product.

[0027] In a preferred embodiment, at least one barrier comprises a substantially flat end surface. The use of a substantially flat end surface results in a substantially flat and consistent contact surface after imprinting using the stamp according to the present invention. For example, it is conceivable that the end surface of the at least one barrier is substantially flush with the layer thickness or base surface of the stamp. It is also conceivable that the end surface of the at least one barrier is at least partially structured. For example, it is also possible that at least a portion of the end surface of the at least one barrier is substantially structured, thereby providing a substantially rough contact surface. This may be beneficial for a subsequent bonding step applied to the resulting product. It is also conceivable that at least a portion of the contact surface is rough. At least a portion of the contact surface can be applied as a bonding surface.

[0028] The stamp may also include multiple barriers, for example, multiple barriers surrounding a textured region, or a repeating pattern may be applied, for example, with at least two textured regions and at least two barriers, or a double barrier configuration may be applied.

[0029] In a possible embodiment, the stamp comprises at least one reservoir element, preferably a plurality of reservoir elements, which define a reservoir volume. The at least one reservoir element may, for example, comprise at least one reservoir ridge, preferably a plurality of reservoir ridges. The at least one reservoir element is preferably positioned adjacent to the at least one barrier. More specifically, the at least one reservoir element is preferably positioned on the opposite side of the at least one barrier relative to the textured region.

[0030] It is conceivable that the defined reservoir region is open to the edge of the stamp to allow excess resin to flow out during imprinting. The reservoir elements are preferably configured to guide excess resin away from the textured region and the barrier. In a beneficial embodiment, at least one reservoir element is located on at least one outer edge or periphery of the stamp. In this configuration, the reservoir element does not affect the main elements of the stamp. For example, it is conceivable that at least one reservoir element is positioned adjacent to at least one barrier element.

[0031] It is also conceivable that the at least one barrier element is substantially surrounded by a plurality of reservoir elements, which in particular define a reservoir volume. It is also conceivable that the at least one reservoir element has a height equal to or less than the maximum height of the at least one barrier. Preferably, the height of the at least one reservoir element is substantially equal to the maximum height of the at least one barrier. The height of the at least one reservoir element may be less than or greater than the maximum height of the at least one barrier. For example, the at least one reservoir element is defined by a ridge having a height equal to or less than the maximum height of the at least one barrier. The ridge allows, for example, the formation of a resin layer on the substrate with a thickness of up to 5 microns, and the ridge may be interrupted by channels that allow resin to flow between the active area and the blank area of the product during the imprinting process.

[0032] The stamp according to the present invention can be configured to create a product having a blank area and an active area. The product can have, for example, a resin layer having an active area and a blank area, the resin layer preferably having a thickness of up to 5 microns over at least 15% of the blank area. The stamp can also be said to have a blank area and an active area. The active area can be defined by a textured area and / or at least one barrier. In one embodiment, the blank area of the stamp includes an open volume domain of height equal to, greater than, or less than the height of the active area, thereby allowing resin to collect outside the active area. The region of equal, greater, or less height may be referred to as a reservoir area because it can capture resin overflow that may occur in the active area. The reservoir area may be separated from the active area by an extended ridge.

[0033] In one embodiment, the reservoir region comprises small ridges rather than a single depression with a large surface area in the textured layer of the stamp. This is important when the stamp is flexible, especially in roll-to-plate imprinting, where large depressions in a flexible stamp can be pushed out by the pressure of the imprint roller, causing uncontrollable resin flow and significant adverse effects on both the imprint results and the equipment. Poor imprint results can result because the resin can reach undesired locations and the equipment can be contaminated by the splattered resin. For flexible stamps, especially in roll-to-plate processes, it is important that the large surface area of the depression is supported. The ridges supporting the reservoir region can be shaped like pillars, thus supporting the reservoir region like micron- or nanoscale pillar-like holes.

[0034] In one embodiment, the blank area of the stamp is shaped to allow resin to flow out in a controlled manner either around the entire periphery of the blank area or at specific locations. This means that the flow of resin is not blocked underneath the stamp, and the blank area may be provided with outlets for the purpose of controlling the pressure and amount of resin underneath the stamp. In one embodiment, the outlets may be formed such that the "columnar hole structures" of the reservoir texture reach the edge of the texture layer either around the entire periphery of the stamp or only at specific locations.

[0035] In some embodiments, the extended ridges do not form a solid boundary around the active area, which does not block resin flow within that area. Rather, the extended ridges are separated by small channels that can function as outlets for the active area, thus allowing for control of resin flow and resin pressure below the active area of the stamp. Potentially, both the reservoir area and the extended ridges are blank area-only features. The reservoir ridges can also be formed as blocks, cones, cylinders, triangular prisms, rods, flat surfaces, or other shapes.

[0036] Imprint results obtained using a stamp according to the present invention result in a resin layer having a thickness of up to 5 microns, 2 microns, 1 micron, or 0.5 microns at the locations imprinted by the extended ridges, with the height of the ridges and depth of the recesses typically measured from the second surface of the textured region.

[0037] The invention also relates to a method for producing an imprinted substrate with a variable depth pattern, in particular by using a stamp according to the invention. The method comprises: - applying (a portion of) at least one resin onto at least one stamp and / or at least one substrate to be imprinted; imprinting at least a portion of the resin using at least one stamp, preferably the at least one stamp comprising at least one textured area and at least one barrier adjacent to at least a portion of the textured area, the at least one barrier being configured to create at least one contact surface, resulting in a substrate provided with an imprinted resin layer having an imprinted texture at least partially adjacent to and / or surrounded by the at least one contact surface, the maximum residual layer thickness of the at least one contact surface being in particular smaller than the maximum residual layer thickness of the imprinted texture.

[0038] The method according to the present invention results in the production of a product having a texture and a uniform area with a relatively small thickness that can function as a contact surface. The term imprinted substrate also refers to a substrate with an imprinted resin layer, and vice versa. Such a contact surface can be used, for example, to enable electrical and / or thermal contact and / or for sealing purposes. The method according to the present invention eliminates additional processing steps for forming the contact surface, such as etching, mechanical removal, or ablation. In particular, the use of a stamp comprising at least one barrier according to the present invention contributes to achieving this result. This method allows the production of imprinted products with substantially uniform areas or contact surfaces, particularly with a thickness of 5 μm or less.

[0039] The stamp applied in the method according to the present invention may be any of the embodiments described for the stamp according to the present invention. At least a portion of the at least one barrier of the stamp applied in the method preferably has a substantially uniform height higher than the highest peak of the at least one textured region. The at least one barrier in particular extends over at least the length of at least one side of the textured region. The at least one stamp is preferably a flexible stamp.

[0040] The resin applied in the method according to the present invention is in particular an imprint resin. When referring to resin, the term lacquer can also be used. In the context of the present invention, the terms "lacquer" and "resin" can be used synonymously. The lacquer or resin according to the present application can be any liquid or viscous monomeric, oligomeric, or polymeric material that can be transferred to a solid material without significantly changing its shape and size, and therefore without shrinking, cracking, or expanding.

[0041] Typically, the resins or lacquers used herein are materials that can be polymerized using, for example, heat and / or radiation, such as visible or ultraviolet light. For this purpose, the lacquer or resin may contain a radical initiator. Possible radical initiators include azo compounds such as azobisisobutyronitrile, peroxides such as dibenzoyl peroxide or peroxodisulfates, phosphine oxides such as diphenylphosphine oxide, aromatic ketones such as 1-hydroxycyclohexylphenyl ketone or 2-hydroxy-2-methylpropiophenone, and Norrish type II initiators such as methylbenzoyl formate. Possible cationic and anionic initiators include benzenesulfonate esters, alkylsulfonium salts, or photobase generators such as triphenylsulfonium (cationic), tetrafluoroborate, or 2-nitrobenzylcyclohexylcarbamate (anionic). Depending on the initiator, solidification can be initiated by heat or radiation, such as UV light.

[0042] In one embodiment, the resin may be a polymer containing monomers and / or oligomers such as, for example, epoxides, thiols, polyvinyl resins, acrylates, methacrylates, polyethers, vinyl ethers, urethane acrylates, polyesters, fluorinated acrylates, fluorinated methacrylates, fluorinated polyethers, siloxanes, siloxane acrylates, or mixtures thereof. Additionally, copolymers of the named monomers and oligomers of one or more of the named monomers may also be used. In one embodiment, the hardened resin is impermeable or at least has low permeability to water. In one embodiment, the resin is free of, or at least essentially free of, solvents.

[0043] In one embodiment, the resin has the same chemical composition throughout the layer. The resin is applied to the surface of the product and textured by a stamp. The stamp used may therefore be a flexible stamp. Flexible stamps may be used in a roll-to-plate process. While in contact with the stamp, the resin is solidified by heat and / or radiation, and after solidification, the stamp can be separated from the resin, leaving a textured resin layer on the product. The stamp may be substantially transparent and / or translucent. The stamp is preferably transparent to at least ultraviolet light.

[0044] The method according to the invention preferably relates to a roll-to-plate imprinting method, but alternatively it can also relate to a roll-to-roll imprinting method or a plate-to-plate imprinting method.

[0045] The method according to the invention has the advantage that it is possible to produce a relatively thin residual layer, at least in the region of the contact surfaces obtained. The maximum residual layer thickness on at least one contact surface can be, for example, up to 5 μm. It is also conceivable that the maximum residual layer thickness on at least one contact surface is less than 5 μm, preferably less than 3 μm, and more preferably between 2 μm and 1 μm. It is also conceivable that the residual layer thickness on at least one contact surface is in the range of 0.05 to 5 μm, in particular 0.1 to 2 μm, and even more particularly 0.5 to 1.5 μm.

[0046] The textured areas of the stamp define a volume, and the amount of resin applied is preferably greater than the volume defined by the textured areas. Thus, to ensure sufficient resin to form the desired imprint, an excess amount of resin is applied. The method according to the present invention may potentially include multiple steps for forming a resin layer, at least partially 5 microns thick or less, including: providing a substrate; providing a stamp, the stamp including a texture of openings and ridges, the ridges forming a volume; dispensing an amount of resin into the stamp that is greater than the volume of the openings but does not cover the ridges of the stamp; contacting the stamp with the substrate; curing the resin while the stamp is in contact with the substrate; and removing the stamp from the substrate.

[0047] The substrate of the present application is not particularly limited and may be any rigid item including a planar surface that needs to be textured. Thus, the substrate may be a slab of glass, metal, ceramic, or resin, or a laminate of such materials with each other or with other materials. Furthermore, the substrate may be a fabricated or prefabricated device, such as, for example, a display, a photovoltaic cell, a light screen, or a prefabricated product thereof. The substrate may comprise, for example, glass, metal, ceramic, and / or combinations thereof.

[0048] The dispensing may involve printing techniques, using devices that operate according to the same principles as inkjet printers to dispense the resin onto the stamp. In one embodiment, the resin may be pre-cured after dispensing to increase its viscosity and ensure that it remains within the recesses of the stamp until fully cured. It is also envisioned that the resin may be applied in multiple small amounts, e.g., droplets. It is also envisioned that the resin may be applied in regular and / or irregular patterns.

[0049] The method may include the steps of curing at least a portion of the resin, particularly if the stamp is in contact with the resin, and, if necessary, removing the stamp from the substrate or separating the stamp and the substrate. It is also conceivable to pre-cure at least a portion of the resin before curing if the stamp is in contact with the substrate. The viscosity of the applied resin is preferably in the range of 1 mPas to 4000 mPas at 25°C. Preferably, the viscosity of the resin is less than 1000 mPas at 25°C, more preferably less than 500 mPas at 25°C.

[0050] The present invention also relates to an imprinted product, in particular an imprinted product imprinted with a stamp according to the present invention and / or obtained by applying a method according to the present invention, said product comprising a resin layer comprising at least one textured region and at least one contact surface, the maximum residual layer thickness of the at least one contact surface being smaller than the maximum residual layer thickness of the textured region, preferably at most 5 μm.

[0051] In particular, the maximum residual layer thickness of the resin layer defining at least one contact surface is preferably at most 5 μm. It is also conceivable that the maximum residual layer thickness is less than 5 μm, preferably less than 3 μm, more preferably between 2 μm and 1 μm. It is also conceivable that the residual layer thickness is in the range of 0.05 to 5 μm, in particular 0.1 to 2 μm, and more particularly 0.5 to 1.5 μm. It is conceivable that the resin layer has a thickness of at most 1 μm, preferably at most 0.5 μm, in particular in at least 15% of the blank area.

[0052] The product may further comprise at least one conductive layer, preferably an electrically conductive layer, disposed at least partially below the contact surface and / or textured region. The product may also comprise, for example, a transparent material and / or a liquid crystal material at least partially on top of a resin layer. The transparent layer may be made of a transparent conductive material, preferably indium tin oxide (ITO). The product according to the present invention is not particularly limited and may, for example, be a rigid product comprising a planar surface. The product may need to be textured. The product may, for example, be a slab of glass, metal, polymer, ceramic, or resin, or a laminate of such materials with each other or with other materials. The product may also be a fabricated or prefabricated device, such as a display, a photovoltaic cell, a light screen, or any prefabricated product thereof.

[0053] In one embodiment, the product of the present application may be a substrate provided with a resin layer, at least a portion of which has an optical surface and an optical surface texture, and at least a portion of which may have at least one contact surface or bonding surface, the contact surface having a thickness optimized for electrical contact and the bonding surface having a surface texture optimized for mechanical bonding, e.g., sealing bonding.

[0054] It is also conceivable that at least one interface is formed by a portion of the contact surface. The contact surface defined by the present invention can be used as the interface. In one embodiment, both the contact surface and / or the interface are present on one resin layer. The product may include a conductive layer at least partially below the resin layer. The conductive layer may be a closed layer or pattern of a conductive material, such as a metal, e.g., copper, silver, aluminum, etc., or a non-metallic conductive material, e.g., graphite, graphene, or a conductive polymer, e.g., polyacetylene, polythiophene, etc., such as an electrical circuit. The conductive material may be a transparent conductive material, e.g., a doped metal oxide, e.g., indium tin oxide (ITO), fluorine-doped tin oxide, aluminum-doped zinc oxide, or antimony-doped tin oxide.

[0055] The conductive layer may be located directly below the resin layer or may be separated from the resin layer by an additional layer. The conductive layer may be composed of multiple materials, where the different materials may be partially transparent or opaque. The different materials may be arranged side by side or on top of each other. In one embodiment, a transparent conductive layer may be adjacent to, or partially or completely surrounded by, an opaque conductive layer. In one embodiment, the product may include a transparent material at least partially below the resin layer. The transparent material may be any transparent material known to those skilled in the art, such as polymers such as polycarbonate, polymethyl methacrylate (PMMA), polystyrene, various types of silicate-based glasses such as soda-lime glass, potassium lime glass, borosilicate glass, lead glass, and quartz glass, and conductive transparent materials such as indium tin oxide (ITO), fluorine-doped tin oxide, aluminum-doped zinc oxide, or antimony-doped tin oxide.

[0056] The transparent material may be a monolithic layer or may include multiple layers of different transparent materials, such as an ITO layer on a panel of soda lime glass or PMMA. The layer of transparent material may be located directly below the resin layer or may be separated from the resin layer by an additional layer. In one embodiment, the layer of transparent material and the conductive layer are the same layer. In one embodiment, the product includes a liquid crystal layer on top of the resin layer. In such an embodiment, the liquid crystal layer may be separated from the resin layer by a different material, which may be, for example, a transparent and / or conductive material according to the present application, rather than being located directly below the resin layer.

[0057] The product may further include a sealing layer that can be disposed adjacent to the conductive layer and / or the transparent layer. This sealing layer may be glass, metal, resin, or other rigid material with low permeability to water and air. The resin layer on the product generally has distinct active and blank areas. The active areas of the resin layer provide the article with a distinct function, such as a desired visual appearance or a specific optical effect. To this end, the active areas may include texture.

[0058] The texture may thus be referred to as a "functional texture" or an "optical texture." However, in some embodiments, the active area may be a smooth surface. The blank area is an area where the resin layer does not have the function of an active area. The blank area may itself be divided into different areas. In the blank area, the function of the resin layer may be a protective function or an adhesion promoter for something adhesively bonded to the resin layer, such as a top seal, which may be placed on top of the sealing layer. However, for various reasons, the blank area may also be textured, and the texture of the blank area may be different from the texture of the active area.

[0059] As an example, the texture of the bonding area may be suitable for bonding the top seal. Depending on the material of the top seal, the bonding area may be smoothly textured, slightly sandy, or have other textures known to those skilled in the art. In one embodiment, the blank area surrounds the active area or is at least partially located at the edge of the active area. If the blank area partially surrounds the active area, gaps may be formed in the blank area, for example, for cable access to the active area or for resin flow control. Part of the blank area may be a lead-in area, which is the area of initial contact of the stamp with the substrate in the imprint process. Thus, the blank area may be an area where the resin layer contains errors or imprint defects due to the effects of starting and stopping the imprint process.

[0060] The residual layer thickness of a resin layer can be defined as the smallest distance from the top surface of the resin layer to the surface of the product or substrate on which the resin layer is disposed. The resin layer can have a thickness of up to 5 microns in at least 15% of the blank area. Throughout this application, a resin layer with a thickness of up to 5 microns is referred to as a "thin layer" and the area where it is disposed is referred to as a "thin layer area." In one embodiment, the resin layer may be up to 4.5 microns, 4 microns, 3 microns, 2 microns, 1 micron, or 0.5 microns thick in the thin layer area.

[0061] It is noted that the thickness of the blank area may vary both within the thin layer area and outside the thin layer area. Furthermore, it is noted that the terms "thin layer" and "thin layer area" apply only to the blank area. The thickness of the resin layer in the active area may be higher than 5 microns, lower than 5 microns, or may vary in thickness. In either case, there is no direct relationship between the thickness of the resin layer in the active area and the thickness of the resin layer in the blank area. In one embodiment, the blank area may consist solely of the thin layer area.

[0062] In one embodiment, the thin layer region is at least 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 15% of the blank area. In one embodiment, the thin layer region is at most 90%, 80%, 70%, 60%, 50%, 40%, 30%, or 20% of the blank area. In one embodiment, the entire blank area is a thin layer region. All the thin layer regions of a blank area may be connected to each other to form one thin layer region, or the thin layer regions may be separated by regions where the resin layer is thicker than 3 microns. The thin layer regions may form a pattern that matches the structure on the product.

[0063] In one embodiment, the thinned region may be located entirely or partially within the region of the resin layer on the electrical contact and / or seal. The thickness of the resin layer may be achieved solely by imprinting rather than by subtractive and / or subtractive manufacturing steps, such as, for example, etching, dissolving, milling, skiving, or the use of abrasives. The thinned region on the electrical contact allows for forming an electrical connection to the electrical contact covered with the thin resin layer, for example, through the thin resin layer or by puncturing. In one embodiment, puncturing is performed by localized abrasion or melting and evaporation of the resin, for example, during a soldering process used to secure a wire to the contact region.

[0064] Throughout this application, the term "texture" refers to a three-dimensional structure that includes both openings and protrusions, also known to those skilled in the art as "relief" or "relief texture." In some cases, texture is also referred to as a "pattern," "relief pattern," or "texture pattern." However, the term "pattern" can also refer to a two-dimensional structure created by selectively applying color, such as ink, to a surface, as in printing color on paper. To have an optical effect, the texture may include, for example, small lenses, lenticulars, pyramids, diffraction gratings, or bars that produce a particular optical effect.

[0065] The present invention also relates to a block of rigid material suitable as a master for fabricating textured stamps. The block includes a first side and a second side, the first side containing the texture to be replicated, the texture including functional texture in the active area and passive structures in the blank area, the texture being formed of recesses and ridges, the blank area containing extended recesses that are deeper than the deepest recess in the active area, the depth of the recess measured from the second side of the block. The block, which can be synonymously referred to as a "master," can be fabricated from any rigid material, such as silicon, quartz, glass, steel, aluminum, or other metals. In one embodiment, the material is mechanically and chemically durable, thus robust against mechanical forces and chemical stresses induced by water, oxygen, heat, organic solvents, acids, or bases. The latter, in particular, simplifies cleaning of the master if it becomes contaminated. [Brief explanation of the drawings]

[0066] The present invention is further illustrated by the non-limiting exemplary embodiments shown in the following figures. [Figure 1a] 1 shows a stamp according to the invention and its use in a method according to the invention; [Figure 1b] 1 shows a stamp according to the invention and its use in a method according to the invention; [Figure 1c] 1 shows a stamp according to the invention and its use in a method according to the invention; [Figure 2] 1 shows possible embodiments of a stamp according to the invention, in which like reference numbers correspond to similar or equivalent elements or features. DETAILED DESCRIPTION OF THE INVENTION

[0067] 1a-1c show a schematic diagram of a stamp 100 according to the invention and its use in a method according to the invention for producing a product 50 according to the invention. The figures are perspective views from the side. FIG. 1a shows an initial step before the imprinting process, where a substrate 51 and stamp 100 are provided. FIG. 1b shows the imprinting step, and FIG. 1c shows the product 50 obtained after imprinting, after the stamp 100 has been removed from the substrate 51. The stamp 100 is configured for imprinting, in particular nanoimprinting, and comprises a textured region 101 and a barrier 102.

[0068] The barrier 102 is adjacent to the textured region. The barrier 102 extends the length of at least one side of the textured region 101, and at least a portion of the barrier 102 has a substantially uniform height Hb that is higher than the highest peak Ht of at least one of the textured regions 101. The stamp 100 further comprises a plurality of reservoir elements 103 that define a reservoir volume. In the illustrated embodiment, the reservoir elements 103 are located around the periphery of the stamp 100, and their heights are substantially equal to the height Hb of the barrier 102. The barrier 102 defines a width and a height, and in the illustrated embodiment, the height and width of the barrier are substantially uniform across the barrier 102. The barrier 102 further comprises a substantially flat end surface. The end surface can be at least partially structured, if desired.

[0069] FIG. 1a illustrates a first step of the method, in which a portion of resin 104 is provided on the substrate 51 to be imprinted. The resin 104 may be applied to a stamp 100. FIG. 1b illustrates an imprinting step, in which the stamp 100 is used to imprint at least a portion of the resin 104 on the substrate 51. Due to the stamp 100 including a relatively large amount of applied resin 104 and reservoir elements 103, excess resin 104 is guided toward the edge of the substrate 51. The stamp 100 is configured to generate a texture T and a contact surface C in the formed resin layer 104. After the stamp 100 is removed, an imprinted substrate 51 or product 50 is obtained, as shown in FIG. 1c. The imprinted substrate 51 has an imprinted texture T adjacent to and / or surrounded by the contact surface C, and the maximum residual layer thickness Tc of at least one contact surface is smaller than the maximum residual layer thickness Tt of the imprinted texture region T. The maximum residual layer thickness Tc of the at least one contact surface is in particular at most 5 μm.

[0070] 2 shows a top view of a possible embodiment of a stamp 200 according to the present invention, in particular a flexible stamp 200. The stamp 200 comprises a textured region 201 and a barrier 202 adjacent to at least a portion of at least one of the textured regions 201. The stamp 200 further comprises a plurality of reservoir elements 203 located around the periphery of the stamp 200. The reservoir elements 203 define a reservoir volume. The barrier 202 is a continuous barrier 202 that substantially surrounds the textured region 201. The barrier 202 is enclosed between the textured region 201 and the reservoir elements 203. In the illustrated embodiment, the reservoir elements 203 are positioned at a predetermined distance from each other.

[0071] It is clear that the present invention is not limited to the exemplary embodiments shown and described herein, but that countless variations are possible within the framework of the appended claims, which will be obvious to those skilled in the art, whereby it is possible to envisage combining, fully or partially, the various inventive concepts and / or technical measures of the above-mentioned variant embodiments without departing from the inventive idea as set forth in the appended claims.

[0072] The verb "to comprise" and its conjugations as used in this patent document are understood to mean not only "to comprise" but also to include the expressions "to include," "to substantially include," "to be formed by" and their conjugations.

Claims

1. An imprinting stamp, in particular a nanoimprinting stamp, comprising: At least one texture region; at least one barrier adjacent at least a portion of the at least one textured region; the at least one barrier extends at least the length of at least one side of the textured region; A stamp, wherein at least a portion of at least one barrier has a substantially uniform height that is higher than the highest peak of at least one textured region.

2. The stamp of claim 1 , wherein at least one barrier substantially surrounds at least one textured region.

3. At least one barrier defines a width and a height; The stamp according to any one of claims 1 to 2, wherein at least one barrier has a substantially uniform height and / or a substantially uniform width.

4. The stamp according to any one of claims 1 to 3, wherein at least one barrier is a continuous barrier.

5. The stamp according to any one of claims 1 to 4, wherein at least one barrier has a substantially flat edge.

6. The stamp according to any one of claims 1 to 5, comprising at least one reservoir element, preferably a plurality of reservoir elements defining a reservoir volume.

7. The stamp of claim 6 , wherein at least one reservoir element is located at the periphery of the stamp.

8. 8. The stamp of claim 6 or claim 7, wherein the height of the at least one reservoir element is equal to or less than the maximum height of the at least one barrier.

9. The stamp according to any one of claims 1 to 8, wherein the stamp is a substantially flexible stamp.

10. A method for producing an imprinted substrate with a variable depth pattern, in particular by using a stamp according to any of claims 1 to 9, comprising: - applying at least one resin onto at least one stamp and / or at least one substrate to be imprinted; - imprinting at least a portion of the resin using at least one stamp, the at least one stamp comprising at least one textured area and at least one barrier adjacent to at least a portion of the textured area, the at least one barrier being configured to create at least one contact surface, resulting in a substrate provided with an imprinted resin layer having an imprinted texture at least partially adjacent to and / or surrounded by the at least one contact surface, and wherein the maximum residual layer thickness of the at least one contact surface is smaller than the maximum residual layer thickness of the imprinted texture.

11. The method of claim 10 , wherein at least a portion of the at least one barrier of the stamp has a substantially uniform height that is higher than the highest peak of the at least one textured region.

12. 12. The method according to claim 10 or claim 11, wherein the maximum residual layer thickness on at least one contact surface is at most 5 μm.

13. The method according to any one of claims 10 to 12, wherein the textured area of the stamp defines a volume, and the amount of resin applied is greater than the volume defined by the textured area.

14. The method according to any one of claims 10 to 13, wherein the resin is applied in portions.

15. - curing at least a portion of the resin, especially when the stamp is in contact with the resin; A method according to any one of claims 10 to 14, comprising, after curing, optionally separating the stamp and the substrate.

16. The method according to any of claims 10 to 15, wherein at least one stamp is a flexible stamp.

17. a resin layer including at least one textured region and at least one contact surface; A product imprinted with a stamp according to any one of claims 1 to 9 and / or by a method according to any one of claims 10 to 16, wherein the maximum residual layer thickness of at least one contact surface is smaller than the maximum residual layer thickness of the textured region.

18. 18. The product of claim 17, wherein the maximum residual layer thickness on at least one contact surface is 5 μm.

19. 19. A product according to claim 17 or claim 18, comprising at least one conductive layer, preferably an electrically conductive layer, located at least partially beneath the contact surface and / or textured region.

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