Flexible impression with adjustable high dimensional stability

Abstract

A flexible stamp comprising at least three layers, an upper layer as a texture layer (203) having a relief area (203B), a reinforcing layer (202) and a protective layer (201), characterized in that the reinforcing layer (202) has a thermal expansion coefficient of 10 ppm / °C or less, a Young's modulus of 10 GPa-200 GPa, a layer thickness of less than 300 μm, and an area at least covering the relief area (203B).

Description

[0001] The present invention relates to methods and materials for texturing discrete substrates such as displays, lighting or solar panels by printing a printing lacquer onto a discrete substrate with a dimensionally stable flexible stamp and then curing the printing lacquer, resulting in an additional functional textured layer on the discrete substrate. The function of the additional layer can vary from a light control layer to a hydrophobic layer, decorative applications, use in biosensors or as a resist, among others.

[0002] The use of functional textured layers on substrates is an important topic. Intelligent use of such layers can increase performance, reduce costs or improve the visual appearance of products containing the printed substrate. For example, diffuser layers are used in displays so that thinner LED backlight concepts can be used and the display is illuminated from the side. Other new high-tech possibilities are the integration of functional textured layers into solar panels to increase their efficiency or into organic light-emitting diode (OLED) lighting panels to extract more light.

[0003] Functional textured layers can be manufactured by using imprint lithography. In this case, the substrate or the mold or both are coated with a paint (resin or resist). After the mold is pressed onto the substrate (with the paint in between), the textured paint is cured into a solid phase. The curing method can be heat or UV light irradiation. As early as 1978, this technology was mentioned in U.S. Patent No. 4,128,369. Chou performed further pioneering work in 1995. He proved that by using a rigid stamp, textures less than 25nm can be replicated in high-throughput batch production (U.S. Patent No. 5,772,905), or the article Stephen Y.Chou, Peter R.Krauss, Preston J.Renstrom (Appl.Phys.Lett.67 (1995) 3114–3116). Later, the use of rollers to apply pressure on a rigid mold or a curved thin metal sheet to replicate textures was demonstrated (article Hua Tan, Andrew Gilbertson, Stephen Y. Chou, J. Vac. Sci. Technol., B 16 (1998) 3926-3928).

[0004] Many institutions and companies continued this work, resulting in different technologies.

[0005] In the semiconductor industry, sheet-to-sheet printing is performed by using a rigid stamp in combination with transfer processes, materials, and precise positioning as described in US Pat. No. 6,334,960, US Patent Application 2004 / 0065976, and US Pat. No. 8,432,548.

[0006] Roll-to-roll printing technology uses a texturing roller in combination with a flexible substrate to texturize a foil or film in a continuous process, such as described in US Pat. No. 8,027,086.

[0007] The first mentioned sheet-to-sheet technology is designed for precise, wafer-level printing of small textures (resolution less than 100 nm) with high positional accuracy on uniform flat wafers. However, as described in Chinese patent application CN 103235483, this technology is difficult to scale to larger areas.

[0008] By using roll-to-roll technology, textured foils can be manufactured continuously at high production speeds. These foils can be used as substrates for flexible applications, or can be laminated to rigid substrates. However, the latter comes with the cost of an additional intermediate adhesive layer to bond the textured foil to the rigid substrate or product. Therefore, a third new technology is being developed: direct roll-to-plate printing. Thus, the functional textured layer is applied directly to a separate substrate without an intermediate thick adhesive layer with a thickness of tens to hundreds of microns. In such a process, either a textured roller is used, as exemplified in French Patent 2,893,610, or a removable flexible stamp is used, as disclosed in U.S. Patent 7,824,516.

[0009] There are several advantages to using a flexographic stamp in the roll-to-sheet replication process. The material and the manufacturing process are cost-effective. In addition, the flexographic stamp can be easily replaced. There are also disadvantages to using a flexographic stamp. The most important disadvantage is the limited lateral dimensional stability of polymer-based flexographic stamps. If the temperature, humidity or tension changes inside the device or during processing, the flexographic stamp will expand or contract. For most applications, the expansion coefficient of the flexographic stamp is different from that of the substrate used. In most cases, the substrate is a separate and rigid metal, polymer, silicon or glass plate. Therefore, after the printing process, changing temperature or humidity levels can lead to different lateral dimensions of the printed texture on the substrate. In this case, the optical properties can change or the texture can be placed in the wrong position relative to the underlying structure or pattern applied in a post-processing step. For many applications, only very limited lateral dimensional changes are allowed, for example only a few micrometers on 1 meter.

[0010] The present invention focuses on thermal expansion, since the effect of changes in lateral dimensions with changes in temperature is significant. Changing humidity has a similar effect. Strain or tension can also cause the flexible stamp to deform. In the context of this specification, reference to thermal expansion can also be read as humidity expansion or expansion by tension. Where expansion is mentioned, contraction can also be understood as a form of negative expansion.

[0011] In patent application WO 2016 / 128494, the design of a flexible stamp is described. Thus, the flexible stamp comprises a stamp matrix or matrix layer and a textured layer on top. The flexible stamp can be one or more layers, with a matrix layer and a textured top layer. For the matrix layer, several materials are mentioned, including plastic foil and thin metal sheets.

[0012] Document US 2005 / 0238967 A1 discloses a composite patterning device for soft lithography, wherein the composite patterning device comprises a plurality of polymer layers.

[0013] The straightforward solution to improve the dimensional stability of the flexible stamp is to use a material with very low thermal expansion as the matrix layer. This can be achieved by using flexible reinforced polycarbonate as the matrix layer. The thermal expansion coefficient of these reinforced materials is still high, above 10 ppm / °C.

[0014] In patent application WO 2016 / 128494, the use of metal plates is mentioned. In patent application KR 2008 / 0044052, the use of glass plates as molds for sheet-to-sheet applications is discussed. However, thick glass and metal plates are rigid, which has two main disadvantages: first, the glass plates cannot be guided on rollers, so a flexible stamp is required in the roll-to-roll or roll-to-sheet printing process. Second, delamination of the rigid stamp requires greater forces.

[0015] For roll-to-plate printing, a high degree of flexibility is required because the stamp is transported on a roller. Thin metal is flexible enough, but not transparent, which makes it impossible to perform UV curing through a metal flexible stamp.

[0016] Glass with a thickness above 300 μm is not flexible enough and will break when bent with the required radius. Glass with a thickness below 300 μm may be flexible enough but will crack easily. Even small forces, especially on the edges of the glass, can cause cracks. Additional layers applied to the glass would compromise the dimensional stability of the glass sheet and are therefore not preferred. Therefore, direct solutions cannot be used for roll-to-sheet printing.

[0017] In application WO 2016 / 12849 it is mentioned that more layers can be added to increase robustness. No method is disclosed how this should be done.

[0018] In EP-A-3028771 it is mentioned that to obtain an accurate lamination registration between stamp and substrate, the stamp should have the same expansion coefficient as the substrate on which the texture is replicated. As an example, said patent application discusses the replication of micro- or nano-textures on a steel substrate by using a flexible plate-to-plate stamp with a steel protective layer. The stamp is called a flexible stamp because the texture layer is flexible. The purpose is to use it in a plate-to-plate replication process. Steel stamps cannot be transported on rollers, so the proposed solution cannot be used in a roller-to-plate process. This patent application does show the importance of having stamps with different expansion coefficients for different applications.

[0019] EP-A-3370250 discloses a film mold which may have a three-layer structure including a first resin layer, a first glass substrate layer and a second resin layer. The second resin layer may be a resin or a foil, or a foil added to glass via an adhesive layer. However, in practice, the glass substrate layer is prone to breakage or cracks after repeated use.

[0020] The problem to be solved by the present invention is to provide a dimensionally stable flexible stamp, in particular enabling roll-to-plate printing of free-standing substrates with a low and adjustable coefficient of thermal expansion below 20 ppm / °C, which can be used multiple times without the glass layer providing cracks or breaks. Breakage of the flexible stamp limits the reuse of the flexible stamp. Therefore, the design of a more robust flexible stamp with a low and adjustable coefficient of expansion is important to enable the flexible stamp to be reused and reduce the manufacturing costs.

[0021] The problem is solved by a flexible stamp comprising at least an upper layer as a texture layer (203) and comprising a relief area (203B), a reinforcing layer (202), and a protective layer (201), wherein the reinforcing layer (202) has a thermal expansion coefficient of 10 ppm / °C or less, a Young's modulus of 10 GPa-200 GPa, a layer thickness of 300 μm or less and an area covering at least the relief area (203B), characterized in that the reinforcing layer is masked by at least one layer selected from the texture layer (203), the protective layer (201) and one or more other layers.

[0022] The at least three or more layers of enhanced flexible stamps are capable of printing independent substrates with minimal lateral dimensional changes, which are usually caused by changes in heat and humidity and changes in tension. The multi-layer stamp can be manufactured to have a large area compared to a standard wafer size with a diameter of 300 mm. The thermal expansion of the multi-layer enhanced flexible stamp is significantly lower than the expansion coefficient of current standard flexible stamps. The thermal expansion coefficient of standard polycarbonate is 65-70ppm / ℃. Enhanced flexible foils, such as enhanced polyethylene terephthalate (PET), do have a minimum thermal expansion of 20ppm / ℃. The thermal expansion coefficient can be measured according to ASTM E228.

[0023]

[0024]

[0025] Furthermore, the Young's modulus of the reinforced flexible stamp layer is 10-200 GPa as measured according to ASTM E111.

[0026] The multi-layer reinforced flexible stamp provided in the present invention comprises three or more layers bonded to each other. Thus, the multi-layer reinforced flexible stamp may have a texture layer having a relief area, one or more reinforcement layers having a lower thermal expansion coefficient as the texture layer, and one or more protective layers having a higher thermal expansion coefficient than the reinforcement layer. Thus, the reinforcement layer has an area at least covering the relief area.

[0027] Within the scope of the present invention, the term "masking" has to be understood as meaning that the reinforcing layer is protected, for example from objects or forces that could damage the reinforcing layer. In the flexible stamp, the reinforcing layer is masked by at least one layer, which at least one layer extends at least partially around or over edge and / or corner portions of the reinforcing layer. If one or more layers selected from the texture layer (203), the protective layer (201) and one or more other layers extend at least partially over or around edge and / or corner portions of the reinforcing layer, this layer or these layers are "masking layers".

[0028] The reinforcement layer may be a three-dimensional layer comprising a first main surface, a second main surface and at least one side, the at least one side being perpendicular to the first main surface and the second main surface and being a limit of the extension of the first main surface and the second main surface of the reinforcement layer. Thus, the reinforcement layer may have any suitable form, such as rectangular, trapezoidal, circular or elliptical. Preferably, the reinforcement layer has a rectangular form, such that the reinforcement layer comprises a first main surface, a second main surface and four sides perpendicular to the first main surface and the second main surface.

[0029] The first major surface and the second major surface may be parallel to each other and face in opposite directions.Preferably, the first major surface faces the relief area and the second major surface does not face the relief area.

[0030] In a preferred embodiment, in order to at least partially mask the corners and / or edge portions of the reinforcement layer by at least one layer selected from the group consisting of a texture layer, a protective layer or one or more other layers, the at least one layer extends at least partially around the edge and / or corner portions of the reinforcement layer.

[0031] In another preferred embodiment, the at least one layer masks at least one side and the first and / or second major surface of the reinforcement layer.Preferably, the at least one layer masks at least one side and the first and second major surface.

[0032] In a preferred embodiment, at least one corner portion, preferably at least two corner portions, more preferably at least three corner portions, even more preferably at least four corner portions, most preferably at least all corner portions of the reinforcement layer are at least partially masked by the at least one layer.

[0033] In another preferred embodiment, at least one edge portion, preferably at least two edge portions, more preferably at least three edge portions, even more preferably at least four edge portions, most preferably all edge portions of the reinforcement layer are at least partially masked by the at least one layer.

[0034] The number of masked corner portions and edge portions may also be the same or different.Preferably, all corner portions and edge portions of the reinforcement layer are at least partially masked.

[0035] By at least partially masking the corners and / or edge portions of the reinforcement layer, it is believed that the tendency of the reinforcement layer to crack is eliminated or at least reduced, thereby allowing multiple uses of the reinforced flexible stamp.

[0036] In a preferred embodiment, the at least one layer of the corner and / or edge portion of the masking enhancement layer at least partially masks the first major surface and the second major surface. Preferably, the at least one layer at least partially masking the first major surface and the at least one layer at least partially masking the second major surface are separate layers.

[0037] In another preferred embodiment, the at least one layer masking the corners and / or edge portions of the reinforcement layer surrounds the corners and / or edge portions of the reinforcement layer.

[0038] In a preferred embodiment, the at least one layer of masking enhancement layer corner and / or edge portions extends over the area of ​​the first major surface by at least 10%, preferably at least 30%, even more preferably at least 50%, even more preferably at least 75%, and most preferably at least 95%.

[0039] In another preferred embodiment, the at least one layer that at least partially masks the corners and / or edge portions of the reinforcement layer extends over the area of ​​the second major surface by at least 10%, preferably at least 30%, even more preferably at least 50%, even more preferably at least 75%, and most preferably at least 95%.

[0040] Preferably, the at least one layer surrounding the reinforcement layer at least partially masks corners and / or edge portions of the reinforcement layer.

[0041] The at least one layer can be made of any suitable material, preferably, the one or more other layers are adhesive layers, which include materials selected from the group consisting of glue, pressure-sensitive adhesives, cured organic layers (such as but not limited to acrylate materials), sol-gel materials, epoxy or combinations thereof.

[0042] Preferably, the at least one layer is a texture layer, a protective layer, an adhesive layer or a combination thereof.

[0043] In another preferred embodiment, the flexible stamp comprises a further protective layer on the side of the reinforcement layer opposite to the side facing the relief area of ​​the texture layer, wherein the extension of the further protective layer is smaller than the extension of the reinforcement layer. It is also preferred that the extension of the further protective layer is greater than the extension of the texture layer. The further protective layer can be used as a dimensional stability adjustment layer, which can adjust the dimensional stability of the area where the relief area is located.

[0044] In another embodiment, the flexible stamp comprises one or more additional reinforcement layers.

[0045] The present invention will now be explained in more detail with reference to the following drawings:

[0046] Figure 1 An illustrative printing process according to the invention is schematically depicted.

[0047] Figure 2 Different layouts of a multilayer reinforced flexible stamp with reinforcement layers and protective layers are schematically shown in side view.

[0048] Figure 3 Shown are thermal expansion measurement results for different flexo stamp layouts, including two multi-layer reinforced flexo stamp designs

[0049] FIG. 4 schematically shows a multi-layer reinforced flexible stamp in top and side views with protective layers in four outer regions of the reinforcement layers.

[0050] Figure 5 A multi-layer reinforced flexible stamp is schematically shown in a top view, with protective layers on two outer regions of the reinforcement layers.

[0051] Reference now Figure 1 , showing an exemplary printing apparatus and method according to the present invention, using a multi-layer reinforced flexible stamp. Figure 1 is an example of a possible use of a multi-layer reinforced flexible stamp in an exemplary roll-to-plate printing process. Note that the multi-layer reinforced flexible stamp can be used in different roll-to-plate replication and roll-to-roll replication processes, or even in a plate-to-plate replication process.

[0052] exist Figure 1In the printing device shown, the functional printing layer 103B is applied on top of the substrate 102. The substrate 102 can be any material; preferably, the substrate 102 includes or is made of glass, a metal plate, polycarbonate (PC), polyethylene naphthalate (PEN), polyethylene terephthalate (PET or PETP), biaxially oriented polyethylene terephthalate (BOPET) or polymethyl methacrylate (PMMA). The substrate 102 can have one or more additional layers applied on top of the surface, such as an adhesion promoting layer and / or a transparent conductor layer (e.g., indium tin oxide, aluminum-doped zinc oxide or flour-doped tin oxide) and / or a metal layer (e.g., silver, gold, aluminum). Figure 1 In the embodiment, substrate 102 is coated with a formable print lacquer 103A and printed with a flexible stamp 104, which after curing produces a replicated print texture 103B, which is added on top of substrate 102. The substrate is placed on a platform 101 for guidance and support. The platform 101 can be one or more rollers, a fixed table, a moving table or any other platform that provides sufficient support. Figure 1 In the embodiment, the mold is a flexible stamp 104. In order to transfer the texture 105B on the outer surface of the flexible stamp 104 to the substrate 102, the printed texture 105B (having the opposite texture of the desired cured printed texture 103B on the substrate 102) is pressed onto the independent substrate 102 (with the formable printed lacquer 103A therebetween). Note that the formable lacquer 103A can be as Figure 1 As shown, the formable printing varnish 103A may be deposited on a separate substrate, or the formable printing varnish may be deposited on a flexible stamp 104. Alternatively, the formable printing varnish 103A may be deposited both on the flexible stamp 104 and on the separate substrate 102. The deposition method may be, in particular, dispensing, inkjet printing, slot-dye coating, gravure printing or screen printing. After the formable printing varnish 103A is printed using the flexible stamp 104, the formable printing varnish 103A is thermally cured or cured by using UV. Figure 1In the embodiment of the present invention, the formable lacquer is cured by using UV light 107B from a UV light source 107A. The UV light source 107A can be placed above the transparent flexible stamp 104. Alternatively, if the independent substrate 102 is transparent, the UV light source 107A can be placed below the transparent independent substrate 102, or integrated in the platform 101 or placed below the transparent platform 101. After curing the print texture 103B, the flexible stamp 104 is separated from the cured print texture 103B on the independent substrate 102, so that the independent substrate 102 having the cured print texture 103B thereon is spaced apart from the template in the form of the flexible stamp 104. The flexible stamp 104 is installed in the front clamp 106A and the rear clamp 106B. The front clamp 106A is located at the beginning of the flexible stamp 104. The rear clamp 106B is located at the end of the flexible stamp 104. The clamp 106A and / or the clamp 106B can be a plastic or metal rod, possibly with a mounting opening. However, the clamp 106A and / or the clamp 106B may also be tape or any other means of holding the flexible stamp 104 in place.

[0053] The flexible stamp 104 has a supporting flexible stamp matrix 105A and a patterned outer surface 105B, also referred to as a "print texture" or "print pattern". The print texture includes a functional area formed by openings and protrusions, which is referred to as a embossed pattern for those skilled in the art. The embossed patterned outer surface 105B is the negative (or reverse) texture of the print texture 103B on the substrate 102. The flexible stamp matrix 105A and the patterned outer surface 105B can be made of one and the same material such as but not limited to a thin metal plate or a plastic plate by milling, electroplating or hot embossing processes. The disadvantages of thin metal plates are opacity, poor flexibility and higher prices. In the case of large-area roll-to-plate replication, the thin metal plate must be very large, which is a challenge both in practice and in cost. For plastic plates, thermal expansion is determined by the coefficient of expansion of the plastic plate. As discussed for plastic-based materials, this is too large for precise replication applications.

[0054] A multilayer reinforced flexible stamp according to the present invention is provided, comprising a patterned outer surface 105B having openings and protuberances. To be able to bend, the reinforced flexible stamp preferably exhibits a Young's modulus of 0.1 GPa-100 GPa, preferably 5 GPa-50 GPa. Preferably, the multilayer reinforced flexible stamp of the present invention has a thickness of 10 μm-2000 μm, more preferably a thickness of 50 μm-500 μm. The specifications regarding layer thickness and Young's modulus do together result in a bending radius of preferably less than 30 cm, more preferably less than 15 cm, over a width of 50 cm at an applied force of preferably less than 1000 N. Thus, the force is defined as the force applied to the flexible stamp front 106A to pull the flexible stamp to about a quarter roll, such as Figure 1 shown.

[0055] As proposed in this patent application, by using a reinforcing layer, thermal expansion of the flexible stamp and expansion due to increased humidity or tension can be reduced. This reduction is achieved by the features of claim 1. Figure 2 , different layouts of multi-layer reinforced flexible stamps are shown.

[0056] Figure 2 Different layouts of multi-layer reinforced flexible stamps using a reinforcing layer 202 in combination with a texture layer 203 and a protective layer 201 are shown. A large area of ​​flexible protective layer 201 is used to provide flexible properties to make it easy to handle. In addition, depending on the flexible stamp construction, the protective layer 201 can protect the main surface and / or the second surface and / or the side of the reinforcing layer. The protective layer 201 can be, for example, but not limited to, a polyethylene terephthalate (PET or PETP) foil, a polycarbonate (PC) foil, a polyethylene naphthalate (PEN) foil, a biaxially oriented polyethylene terephthalate (BOPET) or a foil made of another polymer. It can also be a cured acrylate material or a cured epoxy material. The material proposed for the protective layer 201 has a Young's modulus of 0.1-10 GPa and has a layer thickness of less than 500 μm, preferably less than 300 μm. The reinforcing layer 202 is deposited on the protective layer 201. It can be a layer 0.5-100 μm thick, such as but not limited to a SiOx layer or a graphene layer. The deposition technology of the reinforcement layer 202 can be sputtering, spin coating or PE-CVD in particular. As the reinforcement layer 202, a thin metal plate, a thin wafer or a thin glass plate can also be used. The reinforcement layer 202 should be flexible and have a typical Young's modulus of 10-200 GPa and a layer thickness of less than 300 μm, preferably less than 200 μm. In the case of an intermediate thin flexible plate, the thin plate should be bonded to the protective layer 201. This can be bonded using an adhesive layer 204, which can be any mounting material, such as a tape placed on top of the transition between the two layers or between the protective layer 201 and the reinforcement layer 202 or the intermediate adhesive layer, which can be glue, a pressure-sensitive adhesive or a cured organic layer (such as but not limited to an acrylate material), a sol-gel material, an epoxy. Therefore, when the adhesive layer 204 at least partially extends around the corners and / or edge portions of the reinforcement layer 202, the adhesive layer 204 can mask the corners and / or edge portions of the reinforcement layer 202. The texture layer 203 has a relief area 203B, which has a texture opposite to that required on the substrate. The material of the reverse texture 203 is an organic layer, such as but not limited to an acrylate material, a sol-gel material, or an epoxy. Depending on the configuration, the texture layer 203 protects the first main surface and / or the second main surface and / or at least one side of the reinforcement layer 202.

[0057] exist Figure 2In FIG. 2A , the reinforcement layer 202 is embedded in the texture layer 203 so that the corners and / or edge portions of the reinforcement layer 202 are at least partially masked. In order to mask the corners and / or edge portions of the reinforcement layer 202, the reinforcement layer 202 may also be embedded in the protective layer 201, such as Figure 2 B. The reinforcing layer 202 can be positioned between the protective layer 201 and the texture layer 203, wherein the embossed area 203B has the opposite texture to that desired on the substrate. However, it can also be on the other side of the protective layer 201, such as Figure 2 As shown in D. Figure 2 The adhesive layer 204 shown in C can be a different material from the texture layer 203. Figure 2 C and Figure 2 In case D, the adhesive layer 204 protects the reinforcing layer 202 by masking the corners and / or edge portions of the reinforcing layer 202. Figure 2 As shown in E, the adhesive layer 204 can also be made of the same material as the texture layer 203. Figure 2 In the specific case shown in E, the monomer or polymer material of the texture layer 203 also serves as a protective layer for the reinforcement layer 202. In particular, when the texture layer 203 surrounds the reinforcement layer 202, the corners and / or edge portions of the reinforcement layer 202 are masked by the texture layer 203. Figure 2 F shows another flexible stamp design, whereby the reinforcement layer is protected between two protection layers 201 and 205. The materials and / or material thicknesses of the two protection layers 201 and 205 can be the same or different. Moreover, the areas of both protection layers 201 and 205 can be the same or different, whereby the shortest protection layer should have the same area as the reinforcement layer 202 at a minimum to cover and protect the reinforcement layer 202. Note that combinations can also be made between different reinforcement layers 202. For example, a thin deposited reinforcement layer 202 is formed on one side of the protection layer 201, and a second thicker reinforcement layer is bonded to the other side of the protection layer 201. For bonding, an adhesive layer 204 is used, which surrounds the reinforcement layer 202 so that the corners and / or edge portions are masked.

[0058] The above-mentioned multi-layer and reinforced flexible stamps have reduced practice.Flexible stamps are made in different configurations. Figure 3 The measured data are shown.

[0059] like Figure 3As shown, the thermal expansion of the standard flexible stamp with embossed area (203B) on top of the polycarbonate foil is too large. The value of 70 ppm / °C is much higher than the preferred maximum expansion of 20 ppm / °C. The measured values ​​are in good agreement with the theoretical values. As for the multilayer reinforced flexible stamp 1 (MSFS 1), having embossed area on top of a 250 μm polycarbonate protective layer and a 100 μm thin glass plate as reinforcement layer encapsulated between the above 250 μm polycarbonate protective layer and a second 250 μm polycarbonate protective layer, as shown in FIG. Figure 2 Design F shows an expansion of 15 ppm / °C. This expansion can be further reduced if a 100 μm thin glass sheet is encapsulated between two 125 μm polycarbonate layers. In this case, the expansion is reduced to 8 ppm / °C. Figure 3 It was shown that the expansion of the multi-layer reinforced flexible stamp can be adjusted in the range of 5-20 ppm / °C. Therefore, the expansion of the reinforced flexible stamp can be adjusted to match different substrate materials. Figure 3 As shown, the minimum bending radius of the multilayer reinforced flexible stamp 2 (MSFS 2) was determined. The minimum bending radius was observed to be 15 mm. This is lower than the 90 mm bending radius stated by the glass manufacturer. In own tests, a bending radius of 35 mm was achieved for 100 μm bare glass. This confirms that the use of a multilayer stack does protect and improve the stability of the flexible stamp.

[0060] Using similar materials, different stamp layouts can be realized. When using thin glass sheets, the outer edges and corners are most susceptible to damage. During handling, transport or use of the flexible stamp, knocks on the edges can lead to cracks in the glass. As a result, the flexible stamp can no longer be used. In order to further improve the reusability of the flexible stamp, a flexible stamp design with a combination of a stable inner replication area and an outer protection area has been proposed.

[0061] exist Figure 4AIn FIG. 1 , an example of a thermally stable replication area with an outer protective area 301 is shown. In this case, a protective layer 201 with a protective layer area 301 is used, which has an inner open area 303. This inner open area 303 is most likely rectangular, but can also be circular or any other shape. The size of the reinforcement layer area 302 is larger than the inner open area 303. This creates a mounting overlap area 304, in which the reinforcement layer 202 with the reinforcement layer area 302 is mounted on top of the outer protective area 301. In order to mount the reinforcement layer area 302 on top of the outer protective area 301, any stable adhesive layer material 204 can be used as, for example, a tape or an intermediate adhesive layer, such as glue, UV acrylate or a pressure-sensitive adhesive layer. This adhesive layer 204 protects the reinforcement layer 202 by masking the sides and / or corner portions of the reinforcement layer 202. A texture layer 203 with a embossed area 203B is added on top of the reinforcement layer 202. Preferably, the embossed area 203B is completely placed within the inner open area 303. Figure 4B A schematic cross section through a textured region of a reinforced flexible stamp with an outer protective region is shown, as Figure 4A For the safest handling, the outer protection area 301 includes two layers of protection layer 201 and protection layer 205, which are placed below and above the reinforcement layer 202, such as Figure 4C As shown. The materials and / or material thicknesses of the protective layers 201 and 205 can be the same or different. Moreover, the adhesive layers 204A and 204B can be the same material or different mounting materials. Therefore, the adhesive layers 204A and 204B are separate layers, but the adhesive layers 204A and 204B can also be a layer (not shown) surrounding the corners and / or edge portions of the reinforcement layer 202. By selecting different thicknesses of the protective layer 201 and different materials of the protective layer 201, the thermal expansion of the multi-layer reinforced flexible stamp can be adjusted to match the thermal expansion of the substrate. Figure 4D A multi-layer reinforced flexible stamp layout is shown, where only the protective layer 205 has an internal open area 303. The protective layer 201 does not have an internal open area 303 and does cover the reinforcement layer. The adhesive layers 204A and 204B are separate layers, but the adhesive layers 204A and 204B can also be a layer that surrounds the corners and / or edge portions of the reinforcement layer 202 (not shown).

[0062] exist Figure 5 In FIG. 3 , another layout of a reinforced flexible stamp with an outer protection area 301 is shown. Figure 5is a modification of the layout shown in FIG. 4 , in which the inner open area 303 is placed over the entire width of the protective layer 202. In this case, the protective layer 201 protects only the edges and the two most vulnerable sides of the reinforcing layer 202. Preferably, the two sides of the reinforcing layer 202 protected by the protective layer are at the starting area 302A and the end area 302B relative to the printing direction. The starting area 302A is the most fragile and is the first to come into contact with the substrate during the printing process. The inner open area 303 does not have a protective layer 201. Preferably, the embossed area 203B is completely placed within the inner open area 303. This results in a high dimensional stability of the embossed area 203. The dimensional stability of the embossed area can be adjusted by adding another protective layer 601 on the side of the reinforcing layer 202 opposite to the side facing the embossed area of ​​the texture layer, as Figure 6 A and B. In this case, the other protective layer 601 can have a similar center position as the embossed area 203, and its size is larger than the embossed area 203. By using another layer with different dimensional stability in the flexible stamp stack, the dimensional stability of the entire flexible stamp stack can be adjusted. The width of the outer protective areas 301A and 301B has the same minimum width as the width of the reinforcement layer area. Therefore, all corners of the reinforcement layer are protected. Figure 4C and 4D As shown, it can be combined with a second protection layer that has the same layout or completely covers the reinforcement layer 202.

Claims

1. A flexible stamp for roller-to-plate printing, comprising at least an upper layer as a texture layer (203) and comprising a relief area (203B), a reinforcing layer (202) and two protective layers (201, 205), wherein the reinforcing layer (202) comprises a glass layer and has a thermal expansion coefficient of 10 ppm / °C or less, a Young's modulus of 10 GPa-200 GPa, a layer thickness of 300 μm or less and an area covering at least the relief area (203B), wherein the reinforcing layer is masked by two layers, the two layers extending around or over the edge and corner portions of the reinforcing layer so that the reinforcing layer is wrapped by the two layers, wherein the first layer comprises the texture layer (203) and the first protective layer (201), and the second layer comprises the second protective layer (205).

2. The flexible stamp according to claim 1, characterized in that The flexographic stamp has a coefficient of thermal expansion of 5-20 ppm / °C.

3. The flexible stamp according to claim 1, characterized in that The flexographic stamp has a bending radius of less than 30 cm.

4. The flexible stamp according to claim 2, characterized in that The flexographic stamp has a bending radius of less than 30 cm.

5. The flexible stamp according to any one of claims 1 to 4, characterized in that The thickness of the reinforcement layer (202) is 0.5 μm-300 μm.

6. The flexible stamp according to claim 5, characterized in that The thickness of the reinforcement layer (202) is 40 μm-250 μm.

7. The flexible stamp according to claim 5, characterized in that The thickness of the reinforcement layer (202) is 60 μm-200 μm.

8. The flexible stamp according to claim 5, characterized in that The thickness of the reinforcement layer (202) is 80 μm-150 μm.

9. The flexible stamp according to any one of claims 1 to 4, characterized in that The thickness of the protective layer (201) is 10 μm-500 μm.

10. The flexible stamp according to claim 9, characterized in that The thickness of the protective layer (201) is 40 μm-400 μm.

11. The flexible stamp according to claim 9, characterized in that The thickness of the protective layer (201) is 60 μm-300 μm.

12. The flexible stamp according to claim 9, characterized in that The thickness of the protective layer (201) is 80 μm-200 μm.

13. The flexible stamp according to any one of claims 1 to 4, characterized in that The protective layer (201) has a Young's modulus of 0.1 GPa to 20 GPa.

14. The flexible stamp according to claim 13, characterized in that The protective layer (201) has a Young's modulus of 0.1 GPa to 10 GPa.

15. The flexible stamp according to any one of claims 1 to 4, characterized in that The protection layer (201) is located between the texture layer (203) and the reinforcement layer (202).

16. The flexible stamp according to any one of claims 1 to 4, characterized in that The protective layer (201) has a region that at least covers the reinforcing layer (202).

17. The flexible stamp according to any one of claims 1 to 4, characterized in that The protective layer (201) covers the reinforcement layer except for the open areas (303).

18. The flexible stamp according to any one of the preceding claims 1 to 4, characterized in that The reinforcement layer (202) is located between the texture layer (203) and the protection layer (201).

19. The flexible stamp according to claim 16, characterized in that The reinforcement layer (202) is located between the texture layer (203) and the protection layer (201).

20. The flexible stamp according to claim 17, characterized in that The reinforcement layer (202) is located between the texture layer (203) and the protection layer (201).

21. The flexible stamp according to any one of claims 1 to 4, characterized in that The flexible stamp comprises one or more further reinforcement layers (202).

22. The flexible stamp according to claim 1, characterized in that The reinforcing layer is bonded between the protective layer (201) and the second protective layer (205).

23. The flexible stamp according to any one of claims 1 to 4, characterized in that The material of the protective layer is selected from the group consisting of polyethylene terephthalate, polycarbonate, biaxially oriented polyethylene terephthalate, polyethylene naphthalate, cured acrylate material or cured epoxy material.

24. A flexible stamp according to any one of claims 1 to 4, comprising at least an upper layer as a texture layer (203) and comprising a relief area (203B), a reinforcing layer (202), two protective layers (201, 205) and two adhesive layers (204), wherein the reinforcing layer (202) comprises a glass layer and has a thermal expansion coefficient of 10 ppm / °C or less, a Young's modulus of 10 GPa-200 GPa, a layer thickness of 300 μm or less and an area covering at least the relief area (203B), wherein the reinforcing layer is masked by two layers, the two layers extending around or over the edges and corner portions of the reinforcing layer so that the reinforcing layer is wrapped by the two layers, wherein the first layer comprises the texture layer (203), the first protective layer (201) and the first adhesive layer (204), and wherein the second layer comprises a second protective layer (205) and a second adhesive layer (204).

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