CN117067569A - Pressing module, sheet pressing system and sheet pressing method - Google Patents

Abstract

A press module and a sheet embossing system employing the same, and a sheet embossing method are provided. The pressing module comprises a hot plate module pressed against the hydrostatic plate. The hot plate has a patterned mold and is configured to be heated and cooled very rapidly, and the hydrostatic plate is configured to ensure that the pressed sheet is flat during embossing. The embossing system and method continuously feeds the belt between the rollers in successive steps while discretely delivering the belt sections as a sheet for embossing. Rapid heating and cooling of the hotplate is achieved by: selecting a thermally conductive material having a low heat capacity; and hot and then cold water is conveyed through a number of channels traversing the platen material. Sheet control is achieved by controllably venting air and supporting the planar orientation of the sheet by a hydrostatic plate. The system provides for rapid and accurate sheet embossing.

Description

Pressing module, sheet pressing system and sheet pressing method

Background

1. Technical field

The present invention relates to the field of Pattern Transfer (PTP), and more particularly to an apparatus and process for producing a pattern transfer sheet.

2. Background art

Imprinting is a well-known technique for creating patterns in plastic materials, in which a plastic (polymer) material is softened by heating and then pressed against a mold having a predefined pattern. The pattern protrusions penetrate the heated and softened polymer under pressure and during some holding time the polymer replicates the pattern of the mold. The polymer is then cooled and the mold is removed from the polymer.

Two main types of imprinter are (i) rotary imprinter in which the mold is a cylinder and the polymer film is continuously moved by a roll-to-roll system. The throughput is very high but the hold time (time of thermal contact between the drum and the film) is short, so this type is commonly used to produce low aspect ratio topographic patterns without sharp corners; and (ii) a planar imprinter in which the mold and the imprinter are planar and the imprinted material is typically a single polymeric sheet. The hold time is not limited and thus high aspect ratio patterns with sharp corners can be produced, but the yield is generally low. Examples of flat presses are provided, for example, in WIPO publication No.2015/197415, and in european patent No.3,056,329, U.S. patent application publication No.2009/0068306, and U.S. patent No.8,235,697, all of which are incorporated herein by reference in their entirety.

Disclosure of Invention

The following is a brief summary that provides a preliminary understanding of the invention. This summary does not necessarily identify key elements nor does it limit the scope of the invention, but is merely used as an introduction to the following description.

One aspect of the present invention provides a press module in a sheet embossing system, the press module comprising: a platen module comprising a platen having a plurality of bores extending transversely therethrough and in fluid communication with a water supply of hot and cold water, wherein a contact side of the platen comprises a mold having patterned protrusions; and a hydrostatic plate comprising a flexible top cover configured to support the sheet as it is pressed against the patterned mold of the platen, wherein embossing of the sheet is performed by continuously heating and cooling the platen as the platen module is pressed against the hydrostatic plate in a manner that hot water, then cold water, is continuously introduced through the platen, wherein when the sheet is enclosed between the platen and the hydrostatic plate, a space around the sheet is sealed by a seal attached to the hydrostatic plate, air in the sealed space is expelled, and the flexible top cover is flattened to enable controlled embossing of the sheet by the patterned protrusions.

One aspect of the present invention provides a sheet embossing system comprising: (i) a press module comprising: a platen module comprising a platen having a plurality of bores therethrough transversely and in fluid communication with a water supply of hot and cold water, wherein a contact side of the platen comprises a mold having patterned protrusions; a hydrostatic plate comprising a flexible top cover configured to support the sheet as it is pressed against the patterned mold of the platen, wherein embossing of the sheet is performed by continuously heating and cooling the platen as the platen module is pressed against the hydrostatic plate in a manner that hot water, then cold water, is continuously introduced through the platen, wherein when the sheet is enclosed between the platen and the hydrostatic plate, a space around the sheet is sealed by a seal attached to the hydrostatic plate, air in the sealed space is vented, and the flexible top cover is flattened to enable controlled embossing of the sheet by the patterned protrusions; and a piston configured to press the plates against each other to enclose and emboss the sheet between the plates, and to continuously move the plates away from each other to release the sheet; and (ii) a sheet delivery system comprising: an unwind roller with an associated unwind float, a rewind roller with an associated rewind float, and a feeder module, wherein the sheet delivery system is configured to continuously deliver the tape from the unwind roller to the rewind roller while continuously and stepwise delivering the sheet of tape for embossing to the press module.

One aspect of the present invention provides a sheet embossing method including: pressing the sheet on the belt between the hot plate and the hydrostatic plate to form a pattern on the sheet by a mold having patterned protrusions on the hot plate, wherein the pressing comprises: sealing the sheet between the hot plate and the hydrostatic plate to form a sealed space, and evacuating air from the sealed space, flattening the curved top cover of the hydrostatic plate to flatten and support the sheet, and heating and cooling the hot plate by continuously introducing hot water, then cold water, through the hot plate—thereby embossing the sheet.

These, additional, and/or other aspects and/or advantages of the present invention are set forth in the detailed description that follows; possibly inferred from the detailed description; and/or may be learned by practice of the invention.

Drawings

For a better understanding of embodiments of the present invention and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which like reference numerals designate corresponding elements or portions throughout.

In the drawings:

Fig. 1 is a high-level schematic view of a press module in a sheet embossing system in accordance with some embodiments of the present invention.

Fig. 2 is a high-level schematic perspective illustration of a press module according to some embodiments of the invention.

Fig. 3A-3E are high-level schematic diagrams of platens according to some embodiments of the present invention.

Fig. 4 is a high-level schematic top perspective view illustration of a hydrostatic plate in accordance with some embodiments of the present invention.

Fig. 5A to 5D and 6 schematically illustrate a sheet embossing method according to some embodiments of the present invention.

Fig. 7 is a high-level schematic view of a sheet delivery system in a sheet embossing system in accordance with some embodiments of the present invention.

Fig. 8A-8D schematically illustrate operation of a sheet delivery system according to some embodiments of the present invention.

Fig. 9 is a high-level schematic cross-sectional view of a pattern transfer sheet according to some embodiments of the invention.

FIG. 10 is a high-level block diagram of an exemplary controller that may be used with embodiments of the present invention.

It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

Detailed Description

In the following description, various aspects of the invention are described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without the specific details presented herein. Furthermore, well-known features may have been omitted or simplified in order not to obscure the present invention. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways and in combinations of the disclosed embodiments. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Embodiments of the present invention provide an efficient and economical method and mechanism for providing an embossed sheet, for example as a pattern transfer sheet for Pattern Transfer (PTP) systems, and thus provide an improvement in the art of producing Photovoltaic (PV) solar cells and printed circuits for wide-ranging applications.

A press module and a sheet embossing system employing the same, and a sheet embossing method are provided. The pressing module includes a hot plate module provided with a thin metal mold having a desired pattern on a contact side thereof, the thin metal mold being pressed against the hydrostatic plate. The hot plate is configured to heat and cool very rapidly (at least at its contact side), and the hydrostatic plate is configured to ensure that the pressed sheet is flat during embossing. The embossing system and method continuously feeds the belt between the rollers in successive steps while discretely delivering the belt sections as a sheet for embossing. Rapid heating and cooling of the hotplate is achieved by: selecting a relatively thin metal plate as the contact side, the metal plate being made of a heat conductive material having a low heat capacity; and delivering the hot and then cold water through a number of generally parallel tubular channels in the plate that traverse the platen material. The flatness of the sheet across the area is achieved by controllably venting air and supporting the planar orientation of the sheet by the hydrostatic plate. The system provides for rapid and accurate sheet embossing.

The disclosed embodiments provide a roll-to-roll press that combines very high throughput roll-to-roll strip (ribbon) processing with planar press features having high aspect ratios and sharp pattern features. As disclosed herein, to prevent overheated areas between adjacent embossed sections (sheets), the hot plates are configured to avoid heating the belt sections adjacent to the embossed sheets by maintaining a cold edge. As disclosed herein, a high degree of uniformity in heating and cooling the platens over the entire zone area (sheet) is achieved by the configuration of the platens, and the continuous transport of hot and then cold water. In particular, the hot plate may comprise a transversely perforated metal plate having a plurality of inner tubular passages through which a pressurized flow of hot water may be delivered for plate heating and through which a pressurized flow of cold water may be delivered for plate cooling. A large number of evenly distributed channels along the plate, which occupy a large part of the plate volume, enables even heating and cooling over the plate area. At least the Machine Direction (MD) end of the hotplate may be maintained at a thermal gradient of: this thermal gradient reduces the high temperature within the plate to a much lower temperature at the ends of the plate to avoid heating the tape beyond the tape section (sheet) upon embossing. The hot plate may be made of a special metal alloy like a W-Cu alloy or the like, which has a high thermal conductivity and a low specific heat capacity, enabling rapid heating and cooling to a predefined temperature and a high temperature uniformity over the whole plate area.

Pressing is configured to maintain pressure uniformity over a large area section (sheet) by overcoming the challenges of existing mechanical tolerances of the press itself, the top heated plate, and the bottom plate. Providing almost zero pressure non-uniformity at a given practical mechanical tolerance and preventing air bubbles from being generated when the press is rapidly closed-to avoid defects in the embossed sheet. The bottom plate may be designed as a hydrostatic plate, the inner volume of which is filled with oil under controlled pressure, wherein the top cover of the plate is a relatively thin flexible metal plate. The top cover may be slightly curved (convex) to ensure that air is expelled from the gap during closing of the press.

After closing the gap between the top hot plate and the bottom hydrostatic plate with the polymer tape sheet therebetween, the press applies a predefined high pressure to the assembly. If there is any local non-planarity in the contact area, the top cover of the hydrostatic plate will bend and the local pressure will remain uniform over the whole sheet (section) area, regardless of the non-planarity of the included components, and regardless of its root cause. A sealing band is installed along the periphery of the bottom plate to seal the space between the plates, and inside the bottom plate, at least one vacuum valve connected to a vacuum pump evacuates air from the sealed space to prevent bubble formation-once the gap between the top plate and the bottom plate is closed and sealed, the vacuum pump is applied-the vacuum pump sucks any residual (trapped) air in the gap to remove any bubbles in the contact area before applying high pressure.

The press module and sheet embossing system are configured to maintain high throughput while maintaining high quality of embossing, which may be defined by the uniformity of the embossed pattern (e.g., tolerance of embossing groove depth < ±0.5 μm) and the sharpness of the pattern angle (e.g., outer angle radius < ±0.5 μm) across the sheet area. In particular, the following cycling steps are optimized and the duration of the cycling steps is minimized (and monitored and controlled during operation): heating the hot plate, closing the press, establishing the pressing force, holding (embossing process), switching from heating to cooling, cooling the hot plate, opening the press, separating the film (sheet) from the hot plate, zone-exchanging (belt movement by a roll-to-roll system). In particular, the thermal process has been optimized to quickly and accurately perform heating, cooling, switching between heating and cooling, and maintaining of the press. Regarding hardware, the following components have been optimized: the material of the top hot plate is made of a metal alloy with minimum heat capacity and minimum thermal mass, the top cover of the bottom hydrostatic plate is made of a metal with low thermal conductivity (e.g. stainless steel) to reduce heat dissipation from the heated polymer, the switching between pressurized hot and cold water is performed by a dedicated fast valve unit, press closing, force build-up and press opening are performed very fast using a dedicated hydraulic unit controlling the press movement, the separation of the belt from the hot plate after embossing is performed by a very fast moving separating knife (ejector or sheet release unit) and the section (sheet) exchange is performed by a roll-to-roll module with at least one or two floats in both the unwind and rewind modules by means of a very fast section push unit (feeder). Due to these optimization steps, the cycle time of embossing at about 100 ℃ is reduced to below 15 seconds, providing high throughput of the disclosed roll-to-roll sheet embossing system.

Fig. 1 is a high-level schematic diagram of a press module 100 in a sheet embossing system 105, according to some embodiments of the present invention. Fig. 2 is a high-level schematic perspective illustration of a press module 100 according to some embodiments of the invention. The press module 100 includes a hot plate module 120 and a hydrostatic plate 150, the hot plate module 120 and hydrostatic plate 150 being pressed together as disclosed herein to emboss a sheet 95 (e.g., as illustrated in the interposed schematic perspective view, see fig. 7) positioned on the belt 90, the belt 90 being moved stepwise such that its sections are continuously provided as an embossed sheet, e.g., the embossed sheets for pattern transfer described in chinese patent applications nos. 202111321391.3 and 202122732445.7, the entire contents of both of which are incorporated herein by reference. Fig. 3A-3E are high-level schematic illustrations of platen module 120 according to some embodiments of the present invention. Fig. 3A is a top perspective view, fig. 3B is a combined view providing in top and cross-sectional side views a schematic view of tubular transverse bores 125 and associated vertical bores 126 (perpendicular to bores 125) in platens 130 of platen module 120, and mold 122 (operating conditions are further schematically shown in fig. 5A-5D), and a detailed view of thermo-mechanical barrier 135 near the edges of platens 130, fig. 3C providing an example of thermal uniformity achieved over the contact sides of platens 130 of platen module 120 (illustrated as being over a quarter of the contact sides of platens 130) during a heating period according to some embodiments of the present invention, and fig. 3D and 3E schematically illustrate heating and cooling by hot and cold water, respectively and continuously, in a cross-flow configuration of platens 130 in platen module 120 (as a non-limiting example). Fig. 4 is a high-level schematic top perspective view illustration of hydrostatic plate 150 in accordance with some embodiments of the present invention. Fig. 5A-5D and 6 schematically illustrate a sheet embossing method 200 according to some embodiments of the present invention. Fig. 7 is a high-level schematic diagram of a sheet delivery system 180 in the sheet embossing system 105, according to some embodiments of the present invention. Fig. 8A-8D schematically illustrate the operation of a sheet delivery system 180 according to some embodiments of the invention. Fig. 9 is a high-level schematic cross-sectional view of a pattern transfer sheet 95 according to some embodiments of the invention. FIG. 10 is a high-level block diagram of an exemplary controller 190 that may be used with embodiments of the present invention.

The sheet embossing system 105 illustrated in fig. 1 includes a press module 100 configured to emboss a sheet 95 located on the belt 90 (see schematic diagrams of the belt 90 and the sheet 95 in fig. 7) and a sheet delivery system 180 configured to deliver the sheet 95 to the press module 100. The sheet 95 is embossed on the continuous belt 90 and the sheet delivery system 180 is configured to continuously unwind and rewind the belt 90 from the respective rollers while delivering the sheet 95 for continuous and stepwise embossing-as schematically illustrated in fig. 7 and 8B-8D and disclosed below. One or more controllers 190 may be configured to monitor and control the sheet embossing system 105, the pressing module 100, and/or the sheet delivery system 180. The sheet embossing system 105 can be configured as a cleaning system, for example, configured in an enclosed volume and including the air filtration unit 102. Multiple sensing elements, such as one or more optical inspection units 104, may be used to monitor the imprinting process and adjust parameters of the imprinting process as needed.

The press module 100 illustrated in fig. 2 in the open position includes a platen module 120 and a hydrostatic plate 150, the platen module 120 and the hydrostatic plate 150 (in their closed positions) pressing against each other to enclose the sheet 95 between the platen module 120 and the hydrostatic plate 150, and embossing the sheet 95 as disclosed below (see schematic diagrams of the belt 90 and the sheet 95 in fig. 7) and continuously separating, for example by a piston unit 110, to release the sheet 95. The sheet release unit 115 ("ejector", e.g., implemented by a thin flat knife-like or rod-like element) may be configured to separate the embossed sheet 95 from the mold 122 of the hotplate module 120 (see, e.g., schematic diagrams of the mold 122 of fig. 5A-5D and 3B) after releasing (opening) the press module 100 (to overcome possible adhesion between the embossed sheet 95 and the mold 122 during embossing). The additional mechanical elements 112 may include adjustable supports or posts configured to support the movement of the hydrostatic plate 150 relative to the platen module 120 when closing and/or opening the press module 100. The piston unit 110 and the mechanical element 112 may be controlled (e.g., by one or more controllers 190) to coordinate with the sheet delivery system 180 (schematically illustrated in fig. 7 and 8B-8D) to produce smooth operation of the press module 100 in coordination with the sheet delivery system 180. One or more sensors 114 (schematically illustrated) may be positioned to provide accurate position data relating to the plate 120 being moved by the piston unit 110. The one or more controllers 190 may be configured to monitor and control the operation of the press module 100 and/or any element of the press module 100, such as the hot plate module 120, the hydrostatic plate 150, the piston unit 110, the sheet release unit 115, and the like.

In addition to platen 130, platen module 120 (see, e.g., fig. 3A-3E) includes, for example: a barrier plate 121, the barrier plate 121 being configured to prevent heat from being transferred from the platen 130 to the rest of the platen module 120 and the press module 100, and thereby control the thermal mass (degree of heating and cooling mass) of the platen 130 and the thermal cycle it experiences (e.g., prevent heat leakage and maintain temperature uniformity of the platen 130); and a web 123, the web 123 being configured to transfer pressure/force from the press module 100 to an effective nip area on the platen 130. Platen module 120 may also include elements providing mechanical support and fluid management elements, such as tubing 129 and manifold 132, which are disclosed in more detail below.

Platen 130 includes a plurality of bores 125 that traverse platen 130 from side to side and are in fluid communication with water supplies 128 of hot and cold water, respectively, through tubing 129 and manifold 132 (schematically illustrated in fig. 2). The contact side of the hotplate 130 also holds a thin metal mold 122 with patterned protrusions 131 (see non-limiting specific design as provided by the detail view in fig. 3B and the schematic views in fig. 5A-5D, and produces an embossed sheet 95 in the schematic view in fig. 9). The metal mold 122 may be micropatterned according to, for example, a desired pattern for the PV cell, with the paste transferred from the grooves in the embossed sheet to the PV cell (see fig. 5A-5D and schematic diagrams in fig. 9).

Transverse bores 125 through platens 130 may form a dense array of tubular channels 125, tubular channels 125 being configured to rapidly and uniformly receive hot and/or cold water (optionally pressurized hot and/or cold water) to thereby heat and/or cool platens 130 (e.g., see FIGS. 3B-3E). For example, the bore 125 may be sealed at its ends (e.g., by screws 127, fig. 3B) to form a closed channel 125. Because the cross-drilled holes 125 may be optimized to enhance heat exchange, the cross-drilled holes 125 may be very narrow. In some embodiments, the vertical bore 126 (perpendicular to the channel 125) may be wider, in fluid communication with the channel 125, and the vertical bore 126 may be configured to introduce hot and cold water into the channel 125 and to drain from the channel 125 (depending on the direction of flow). The apertures 126 may be perpendicular to the channel 125 and provide fluid communication with a hot water source and a cold water source via a manifold 132 and corresponding inlet and outlet hoses 129, schematically illustrated in fig. 3A. For example, water supply 128 may be provided from a top side of platen module 120, and manifold 132 may be configured to evenly distribute incoming water in holes 126 and channels 125, and evenly drain outgoing water from holes 126 and channels 125. The manifolds 132 on both sides of the platen module 120 may treat the inflow and outflow water, respectively, to maintain the same water flow direction throughout the operation of the press module 100. Manifold 132 and the water delivery unit may be configured to create and maintain a cross-flow of water within platens 130 to create, maintain, and ensure temperature uniformity at least on the contacting sides of platens 130. The drain valve 139 may be used to drain residual water from the channel 125 and manifold 132 before or after operation.

As shown in fig. 3B, the edge of platen 130 includes a peripheral cooling region 134, which peripheral cooling region 134 is optionally in fluid communication (e.g., via a channel 134A through a cold water inlet 138 illustrated in fig. 3A) with a cold water supply 128 (schematically illustrated in fig. 2), and optionally separated from the central platen by a recess 135, recess 135 serving as a non-limiting example of a thermo-mechanical barrier 135. The peripheral cooling zone 134 may remain cool to avoid any thermal effects on the edges of the embossed sheet 95 and thus avoid any trace features being formed on the embossed sheet 95 (e.g., thermal effects may interfere with the continuous filling of features embossed on the sheet 95 with slurry during the continuous pattern transfer). The thermo-mechanical barrier 135 is configured to limit thermal communication between the central portion and the edge 134 of the platen 130, for example by being narrower than the central main portion of the platen 130, thereby limiting heat exchange through the central portion and the edge, as schematically illustrated in the enlarged cross-section shown (in the heating phase, see fig. 3B-3D) with the thermo-mechanical separation of the channel 134A of cold water from the channel 125 of hot water.

The thermal plate 130 may be made of a material having high thermal conductivity and low thermal capacity and low thermal expansion. For example, the thermal conductivity may be higher than 150W/m°K, higher than 200W/m°K, higher than 250W/m°K, or have an intermediate value. For example, the hotplate 130 may be made of a tungsten copper alloy, such as a W/Cu alloy (e.g., 60%/40% by weight) having a thermal conductivity of 220W/m°K. The heat capacity of platen 130, equal to its mass times its specific heat capacity Cp, may be low, for example platen 130 may have a Cp of less than 250J/Kg ℃, less than 200J/Kg ℃, less than 150J/Kg ℃, or an intermediate value. For example, platen 130 may be made of a tungsten copper alloy, such as a W/Cu alloy having a specific heat capacity Cp of 60%/40% at 181J/Kg ℃. The Coefficient of Thermal Expansion (CTE) of the platen 130 may be low, e.g., less than 20.10 ^-6 m/m DEG C lower than 15.10 ^-6 m/m DEG C lower than 10.10 ^{- 6} m/m ℃, or have an intermediate value. Although in some embodiments, a W/Cu alloy (with 60% W and 40% Cu, cte=11.9·10) is used ^-6 m/m deg.c), but other embodiments may use940，/>940 is an alloy of Cu, ni, si, cr having a thermal conductivity of 208W/m DEG K and a specific heat capacity Cp of 380J/Kg ℃ and 17.5.10 ^-6 Coefficient of Thermal Expansion (CTE) at m/mdeg.C. It should be noted that a high specific heat capacity enables +.>940 is not as good as a W/Cu alloy, but can still be used in the disclosed embodiments. The CTE values of the hotplate 130 and the mold 122 may be close (e.g., within 20%, 15%, 10%, or 5% of each other, e.g., the CTE of the hotplate 130 made of a W/Cu alloy is 11.9-10) ^-6 m/mdeg.C, while the die 122 made of Ni has a CTE of 13.10 ^-6 m/m deg.c) or the like to avoid mechanical stresses between the hot plate 130 and the mold 122 during thermal cycling. In some embodiments, a thin separation layer 124 of a material that allows relative sliding may be provided between the platen 130 and the mold 122 to reduce thermally induced mechanical stress between the platen 130 and the mold 122, e.g., a material such as ∈r may be provided between the platen 130 and the mold 122>A thin (e.g., less than 100 μm) separator layer 124 (schematically illustrated in fig. 3B) is made. Since the common material for the imprint mold 122 is nickel, the thermal plate 130 may be composed of a material having a similar CTE (about 13-10 ^-6 m/m C) of a material such as, by way of non-limiting example, a W/Cu alloy or an Ampcoloy alloy. In the case where the CTE values differ too much, the separator sheet 124 may be used to mitigate thermal expansion differences between materials, for example, the separator sheet 124 may be used in the case where Ni is used for the mold 122 and ampcolay is used for the hot plate 130.

Fig. 3C illustrates experimental results simulating heat flow at the contact side of and through a quarter of a hot plate 130 made of a 60%/40% W/Cu alloy—illustrating the high uniformity of temperature at the instant heating of the hot plate 130 and the cooling of the retaining edge 134 as disclosed herein. In experimental simulation, the hotplate 130 was heated from 40 ℃ to 100 ℃ in less than 5 seconds (4.8 seconds) and cooled back in about 3 seconds (3.1 seconds).

As a non-limiting example, fig. 3D and 3E schematically illustrate a counter-current (cross-flow) cycle of hot water, then cold water, through platens 130 to quickly and uniformly heat platens 130 and then cool platens 130. In the non-limiting example illustrated, water is introduced into and discharged from both sets of channels 125 through apertures 126 such that water moves through platens 130 in two opposite directions simultaneously (some apertures 126 and channels 125 are used to transport water in one direction and other apertures 126 and channels 125 are used to transport water in the opposite direction). As shown in fig. 3D, hot water may be introduced into holes 126 via hoses 129 through manifold 132 and into channels 125 through holes 126, then returned from holes 126 and out through manifold 132 via hoses 129—to rapidly and uniformly heat bottom platens 130 of platen module 120 and imprint sheet 95 through mold 122. Continuously, as shown in fig. 3E, cold water may be introduced into holes 126 via hoses 129 through manifold 132 and into channels 125 through holes 126, then returned from holes 126 and out through manifold 132 via hoses 129—to quickly and uniformly cool bottom platen 130. Heat is applied to imprint the sheet 95 through the mold 122, while cooling is applied to release the sheet 95 and allow the hot plate module 120 to separate from the hydrostatic plate 150 after imprinting. The heating and cooling cycle imprints the grooves into the sheet 95 in a desired shape (see, e.g., fig. 9 and related disclosure), wherein the sheet 95 is effectively separated from the mold 122 without damaging the shape of the grooves and avoids artifacts that may have formed without rapid uniform heating and cooling.

In various embodiments, different sets of apertures 126 and channels 125 (and associated hoses 129 connected to apertures 126 via manifolds 132) may be used to receive water flow in opposite directions. While the cross-flow configuration may enhance rapid and uniform heating and cooling of the plate 130, in some embodiments, unidirectional flow may be used instead of cross-flow configuration, hot water circulation, and/or cold water circulation (e.g., to simplify water management where adequate heating and/or cooling rates are achieved with unidirectional flow). The heating and cooling of platens 130 also heats and cools mold 122 because platens 130 are in good thermal contact with mold 122 and platens 130 have a high thermal conductivity and a low thermal mass.

The hydrostatic plate 150 (see, e.g., fig. 4) includes a flexible top cover 160, the top cover 160 configured to support the sheet 95 when pressed against the patterned mold 122 of the hot plate 130. Embossing of sheet 95 (see, e.g., the schematic diagrams in fig. 5A-5D) is performed by continuously heating and cooling platens 130 while platen module 120 is pressed against hydrostatic plate 150 in a manner that continuously introduces hot water, then cold water, through platens 130. When the sheet 95 is enclosed between the hot plate 130 and the hydrostatic plate 150 of the hot plate module 120, the space 152 (see, for example, the schematic diagram in fig. 5B) around the sheet 95 is sealed by a seal 170 (e.g., a seal 170 made of soft silicone) attached to the hydrostatic plate 150, air from the sealed space 152 is discharged, and the flexible top cover 160 is flattened to enable controlled embossing of the sheet 95 by the patterned protrusions 131 (micropattern) of the mold 122.

Fig. 5A-5D illustrate stages of a sheet embossing method 200 in a highly schematic manner, according to some embodiments of the present invention. These method stages are illustrated in a highly exaggerated manner in fig. 5A to 5D to explain the principle of operation of the press module 100. In particular, the bending and flattening of top cover 160 is exaggerated because the maximum bending amplitude of top cover 160 in the center is actually small (e.g., less than 1mm, or less than 0.5 mm), and flattening of top cover 160 refers to the flat surface of support sheet 95 being embossed and keeping sheet 95 flat during embossing. As schematically illustrated, during pressing, (i) the space 152 is sealed (stage 220, fig. 5A), (ii) air in the space 152 is exhausted (stage 225, fig. 5B), and (iii) the top cover 160 is flattened by reducing the pressure that bends the top cover 160 to continuously and controllably exhaust air from the center of the sheet 95 to the periphery of the exhausted air of the sheet 95, and the sheet 95 is supported in a flat position for embossing (stage 230). Upon pressing, hot water, then cold water, is continuously conveyed through the platens 130 of the platen module 120 to imprint the sheet 95, creating grooves 91 in the sheet 95 (stage 240, fig. 5C and 5D), and then the sheet 95 is released from the pressing module 100 (stage 250), and the belt 90 advances (stage 260) to deliver the next sheet 95 for imprinting (fig. 5D).

The hydrostatic plate 150 may include a vacuum unit (e.g., a vacuum generator) 171, the vacuum unit 171 configured to exhaust air from the sealed space 152. For example, venting of air from the enclosed space 152 may be controlled by a vacuum inlet 172 associated with a vacuum generator 171 (schematically illustrated in fig. 2).

The oil pressure control unit 161 may control the pressure that adjusts the shape of the top cover 160, for example, by controlling the pressure of the hydrostatic fluid, such as oil disposed in a gap 165 below the top cover 160, and by a spring mechanism 167, the spring mechanism 167 being in fluid communication with the gap 165 via a hydraulic connection 162 (e.g., schematically illustrated with reference to fig. 4). For example, the oil-filled gap 165 (schematically illustrated in cross-section in fig. 4) may be configured to support the top cover 160 and provide a pressure to flex the top cover 160, thereby slightly bulging the top cover 160 (see, e.g., the highly exaggerated illustrations in fig. 5A-5D), where the pressure is dynamically controlled by a spring unit 167 (schematically illustrated twice in fig. 4) in fluid communication with the oil in the gap 165. As a non-limiting example, the pressure required to fully flex the top cover 160 (e.g., prior to feeding the sheet 95 and the sealed space 152) may be 200 bar, while the reduced pressure to effect embossing of the sheet 95 onto the top cover 160 (e.g., after the sealed space 152 and venting air from the space 152) may be 60 bar. The spring mechanism 167 may be configured to control the pressure at which the top cover 160 is flexed during an imprinting cycle.

It should be noted that the oil pressure control unit 161 is configured to provide a pressure to bend the top cover 160 before receiving a new sheet 95 for embossing, and is configured to enable the top cover 160 to be flattened by controllably reducing the pressure after closing the gap between the platen module 120 and the hydrostatic plate 150 by the press 110, for example, when the platen module 120 is pressed against the hydrostatic plate 150.

The one or more controllers 190 may be configured to control timing of operation of any of the processes such as the press 110, the water delivery unit, the vacuum unit 171 operation portion, the oil pressure control unit 161, and the like.

Fig. 6 is a highly schematic flow chart of a sheet embossing method 200 according to some embodiments of the present invention. The method stages may be performed with respect to the press module 100 and the sheet embossing system 105 described above, and the press module 100 and the sheet embossing system 105 may optionally be configured to implement the method 200. The method 200 may be implemented at least in part by at least one computer processor in any one of the controllers 190, for example. Certain embodiments include a computer program product comprising a computer-readable storage medium having a computer-readable program embodied therewith and configured to perform the relevant stages of the method 200. The method 200 may include the following stages regardless of their order.

The method 200 includes pressing a sheet on a belt between a hot plate and a hydrostatic plate to further form a pattern on the sheet by patterned protrusions on a mold attached to the hot plate (stage 210). The method 200 further comprises: sealing the sheet between the hot plate and the hydrostatic plate to form a sealed space (stage 220), and exhausting air from the sealed space (stage 225); flattening the (slightly convex) top cover of the hydrostatic plate to flatten the sheet (stage 230), for example by controlling the pressure used to bend the top cover while evacuating air from the sealed space; and heating and cooling the hot plate (while pressing) by continuously introducing hot water and then cold water through the hot plate-thereby embossing the sheet (stage 240). Heating and cooling the platens may be performed in a cross-flow configuration to improve the uniformity of heat transfer between the (hot or cold) water and the platens. The method 200 may also include releasing the embossed sheet (stage 250), releasing the embossed sheet, for example by separating the embossed sheet from a hot plate (stage 255, including, for example, mechanical separation by a sheet release unit or stripper), and moving the belt to deliver a continuous sheet for pressing and embossing (stage 260). Method 200 may also include bending and flattening the top cover using hydraulic fluid (stage 235) -wherein bending of the top cover occurs prior to receiving the new sheet for embossing and flattening of the top cover occurs during pressing of the hot plate onto the hydrostatic plate. The hot plate may include a mold having patterned protrusions.

As schematically illustrated in fig. 7 and 8A-8D, the sheet delivery system 180 may include an unwind roller 182, an optional engagement unit 181, and an unwind float 184, a rewind roller 188, and an associated rewind float 186 and feeder module 185 associated with the unwind roller 182. The sheet delivery system 180 is configured to continuously deliver the belt 90 from the unwind roller 182 to the rewind roller 188 (maintaining belt tension and belt cleanliness and position in the cross-machine direction CMD) while continuously and stepwise delivering the sheet 95 of the belt 90 for embossing to the press module 100 (see fig. 1, 7, and 8B-8C, the press module 100 not being shown in fig. 7 for clarity). The rewind roll 188 and unwind roll 182 may include stepper motors for unwinding and rewinding the tape 90, respectively.

The rewind float unit 186 and unwind float unit 184 are configured to adjust continuous tape handling and step-wise continuous sheet delivery (respectively). As schematically illustrated in fig. 8A, both floating units 184, 186 have a movable arm 183, which movable arm 183 moves during step-wise stamping of the sheet 95 to buffer continuous belt movement. For example, as shown in fig. 8B-8D, for successive stages, the motion of the arms 183A, 183B of the unwind and rewind float 184, 186, respectively, is moved to accumulate or release the length of the belt 90 to support successive unwinds and rewinds during successive (stepwise) impressions in the press module 100, as explained below. Some movement of arms 183A, 183B is represented by arrows 263A-263E to show, in a non-limiting manner, accumulation and release of belt 90. Prior to embossing, with the press module 100 open (e.g., in the release phase 250), the float units 184, 186 are at set points, ready to advance the belt 90, with the arm 183A of the unwind float device 184 lowered 263A to accumulate the belt length (fig. 8B). The feeder module 185 (which is also schematically illustrated in fig. 1 and 7) is configured to pull the belt 90 to continue the cycle once the sheet 95 is released from the press module 100. As the tape 90 is continuously released from the unwind roller 182 and continuously collected (with the recently pressed sheet 95) by the rewind roller 188, the arm 183B of the rewind float unit 186 descends 263B to collect and buffer the tape 90, while the arm 183A of the unwind float unit 184 ascends 263C-to move the tape 90 through the press module 100 and deliver the next sheet 95 for pressing (fig. 8C). When the sheet 95 is delivered and embossed in the press module 100, the arm 183B of the rewind float unit 186 rises 263D to release the buffered tape 90 to the rewind roller 188, while the arm 183A of the unwind float unit 184 descends 263E to continuously collect the unwound tape 90 while the intermediate sheet 95 remains stationary during embossing in the press module 100 (fig. 8D). One or more controllers 190 of the sheet embossing system 105, such as the controller 190 controlling the operation of the pressing module 100 and the sheet delivery system 180, are configured to synchronize the belt motion with the embossing stage to ensure that the cycle time is matched and the tension in the belt 90 is controlled during the continuous belt motion and step embossing steps, as schematically illustrated, for example, in fig. 7.

As further schematically illustrated in fig. 7, additional elements of the sheet delivery system 180 may include: a feeder unit 185 (e.g., a piston-based feeder unit 185), the feeder unit 185 configured to step-pull the belt 90 to deliver sections thereof as a sheet 95 for pressing and embossing; a coupling unit 181, the coupling unit 181 being configured to simplify the roller alternatives; a clamp 187, the clamp 187 for separating between the tensioning section of the belt 90 and the embossed sheet 95; ionizers 189A, 189B, ionizers 189A, 189B are configured to clean ribbon 90 and/or remove static charge from ribbon 90 after unwinding ribbon 90 and/or before rewinding ribbon 90, respectively; and possibly additional elements (not shown) for controlling the correct unwinding and rewinding of the ribbon 90.

Fig. 9 is a high-level schematic cross-sectional view of a pattern transfer sheet 95 according to some embodiments of the invention. In certain embodiments, the pattern transfer sheet 95 may include at least a top polymer layer 94, the top polymer layer 94 including grooves 91 (and optional alignment marks) imprinted thereon, as disclosed herein. In the non-limiting example illustrated, the groove 91 is illustrated as a trapezoidal cross section.

It should be noted that while schematic fig. 9 shows periodic trenches 91, these trenches may include trenches, recesses, and/or dimples imprinted into top polymer layer 94 and may have similar or different profiles. For example, the groove 91 may have various profiles (cross-sectional shapes) such as trapezoidal, circular, square, rectangular, and/or triangular profiles. In various embodiments, the pattern of grooves 91 on transfer sheet 95 may include a continuous array of grooves 91 and/or discrete indentations. Note that the term "groove" should not be construed as limiting the shape of the groove 91 to a linear element, but is to be construed broadly to include any shape of groove 91.

The pattern transfer sheet 95 may also include a bottom polymer layer 92, the bottom polymer layer 92 having a melting temperature that is higher than the imprinting temperature of the top polymer layer 94. In a non-limiting example, the top polymer layer 94, if it is made of a semi-crystalline polymer, may have a melting temperature (T) below 170 ℃, below 150 ℃, below 130 ℃, below 110 ℃ (or any intermediate range) _m ) Or may have a glass transition temperature (T) of less than 160 ℃, less than 140 ℃, less than 120 ℃, less than 100 ℃ (or any intermediate range) if it is made of an amorphous polymer _g ). The bottom polymer layer 92 has a melting temperature higher than the melting point of the top polymer layer 94, e.g., higher than 100 ℃ (e.g., where the top polymer layer 94 is made of polycaprolactone and has a T of about 70 ℃) _m /T _g Higher than 120 ℃, higher than 150 ℃, higher than 160 ℃ (e.g., biaxially oriented polypropylene), and up to 400 ℃ (e.g., certain polyimides), or an intermediate value.

In various embodiments, the polymer layers 92, 94 may be made of at least one of the following materials: polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, wholly aromatic polyesters, other polyester copolymers, polymethyl methacrylate, other acrylate copolymers, polycarbonates, polyamides, polysulfones, polyethersulfones, polyetherketones, polyamideimides, polyetherimides, aromatic polyimides, cycloaliphatic polyimides, fluorinated polyimides, cellulose acetate, cellulose nitrate, aromatic polyamides, polyvinyl chloride, polyphenols, polyarylates, polyphenylene sulfide, polyphenylene oxides, polystyrene, or combinations thereof, provided that the melting or glass transition temperature (T) of top polymer layer 94 _m /T _g ) Below the melting temperature or glass transition temperature (T) of the bottom polymer layer 92 _m /T _g ) And/or so long as the bottom polymer layer 92 is not affected by the processing conditions of the top polymer layer 94.

In certain embodiments, bottom polymer layer 92 and top polymer layer 94 (respectively) may be between 10 μm and 100 μm thick, for example, between 15 μm and 80 μm thick, between 20 μm and 60 μm thick, between 25 μm and 40 μm thick, or within any intermediate range, wherein bottom polymer layer 92 is preferably at least as thick as top polymer layer 94. The polymer layers 92, 94 may be attached by an adhesive layer 93 that is thinner than 10 μm (e.g., thinner than 8 μm, thinner than 6 μm, thinner than 4 μm, thinner than 2 μm, or has any intermediate thickness). For example, in some embodiments, top polymer layer 94 may be several microns thicker than the depth of trench 91, e.g., 5 μm thick, 3 μm to 7 μm thick, 1 μm to 9 μm thick, or as high as 10 μm thick. For example, trench 91 may be 20 μm deep, top polymer layer 94 may be between 20 μm and 30 μm thick (e.g., 25 μm thick), and bottom polymer layer 92 may be in the range between 15 μm and 35 μm thick (note that thicker bottom polymer layer 92 provides better mechanical properties).

The disclosed sheet 95 may be used for printing thin lines of thick metal paste on silicon wafers, for example for Photovoltaic (PV) cells, and for producing electronic circuits by creating wires or pads or other features for printed passive electronic components such as resistors or capacitors or for other printed electronic devices, for example on laminates for PCBs. Other applications may include creating conductive features during the manufacturing process of: mobile phone antennas, decorative and functional automotive glass, semiconductor Integrated Circuits (ICs), semiconductor IC package connectors, printed Circuit Boards (PCBs), PCB component assemblies, optical biological, chemical and environmental sensors and detectors, radio Frequency Identification (RFID) antennas, organic Light Emitting Diode (OLED) displays (passive or active matrix), OLED lighting tiles, printed batteries, and other applications.

FIG. 10 is a high-level block diagram of an exemplary controller 190 that may be used with embodiments of the present invention. The controller 190 may include one or more controllers or processors 193, an operating system 191, memory 192, storage 195, input devices 196, and output devices 197, which one or more controllers or processors 193 may be or include, for example, one or more central processing unit processors (CPUs), one or more graphics processing units (GPUs or general purpose gpus—gpus), chips, or any suitable computing device or computing-related device.

The operating system 191 may be or may include any piece of code designed and/or configured to perform tasks related to coordinating, scheduling, arbitrating, supervising, controlling, or otherwise managing the operation of the controller 190, such as the execution of a scheduler. The memory 192 may be or include, for example, random Access Memory (RAM), read Only Memory (ROM), dynamic RAM (DRAM), synchronous DRAM (SD-RAM), double Data Rate (DDR) memory chips, flash memory, volatile memory, non-volatile memory, cache memory, buffers, short term memory units, long term memory units, or other suitable memory units or storage units. Memory 192 may be or include a plurality of possibly different memory units. Memory 192 may store, for example, instructions (e.g., code 194) for performing the methods and/or store data such as user responses, interrupts, and the like.

Executable code 194 may be any executable code such as an application, program, process, task, or script. Executable code 194 may be executed by controller 193 under the control of operating system 191. For example, executable code 194, when executed, may result in the generation or compilation of computer code or the execution of an application such as VR execution or reasoning, in accordance with embodiments of the present invention. Executable code 194 may be code produced by the methods described herein. For the various modules and functions described herein, one or more computing devices and/or components of controller 190 may be used. An apparatus including components similar to or different from those included in the controller 190 may be used, and may be connected to a network and used as a system. The one or more processors 193 may be configured to execute embodiments of the present invention by, for example, executing software or code.

The storage 195 may be or include, for example, a hard disk drive, a floppy disk drive, a Compact Disk (CD) drive, a recordable CD (CD-R) drive, a Universal Serial Bus (USB) device, or other suitable removable and/or fixed storage unit. Data such as instructions, code, VR model data, parameters, etc. may be stored in the memory 195 and may be loaded from the memory 195 into the memory 192, where the data may be processed by the controller 193. In some embodiments, some of the components shown in fig. 10 may be omitted.

The input device 196 may be or include, for example, a mouse, keyboard, touch screen or touchpad, or any suitable input device. It will be appreciated that any suitable number of input devices may be operatively connected to the controller 190, as indicated at block 196. Output device 197 may include one or more displays, speakers, and/or any other suitable output device. It will be appreciated that any suitable number of output devices may be operatively connected to the controller 190, as indicated at block 197. Any suitable input/output (I/O) devices may be connected to controller 190, for example, a wired or wireless Network Interface Card (NIC), a modem, a printer or facsimile machine, a Universal Serial Bus (USB) device, or an external hard drive may be included in input device 196 and/or output device 197.

Embodiments of the present invention may include: one or more articles of manufacture (e.g., memory 192 or storage 195), such as a computer or processor non-transitory readable medium or a computer or processor non-transitory storage medium, such as, for example, memory, disk drive, or USB flash memory; code comprising or storing instructions, such as computer-executable instructions, that when executed by a processor or controller perform the methods disclosed herein.

The elements from fig. 1-10 may be combined in any operable combination, and the illustration of certain elements in certain figures, but not in other figures, is for illustrative purposes only and is not limiting.

In the foregoing description, embodiments are examples or implementations of the invention. The various appearances of "one embodiment," "an embodiment," "some embodiments," or "some embodiments" are not necessarily all referring to the same embodiments. Although various features of the invention may be described in the context of a single embodiment, such features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment. Certain embodiments of the invention may include features from different embodiments disclosed above, and certain embodiments may incorporate elements from other embodiments disclosed above. The disclosure of elements of the present invention in the context of particular embodiments should not be construed as limiting the use of such elements in only particular embodiments. Furthermore, it is to be understood that the invention may be implemented or practiced in various ways and that the invention may be practiced in some embodiments other than those summarized in the above description.

The invention is not limited to these figures or to the corresponding description. For example, the flow need not be moved through each illustrated box or state or in exactly the same order as illustrated and described. Unless defined otherwise, the meanings of technical and scientific terms used herein are to be commonly understood by one of ordinary skill in the art to which this invention belongs. While the present invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other possible variations, modifications, and applications are also within the scope of the invention. Accordingly, the scope of the invention should not be limited by what has been described so far, but by the appended claims and their legal equivalents.

Claims (20)

1. A press module in a sheet embossing system, the press module comprising:

a platen module comprising a platen having a plurality of bores traversing the platen and in fluid communication with water supplies of hot and cold water, wherein a contact side of the platen comprises a mold having patterned protrusions, and

A hydrostatic plate comprising a flexible top cover configured to support a sheet as pressed against the patterned mold of the platen, wherein embossing of the sheet is performed by continuously heating and cooling the platen as the platen module is pressed against the hydrostatic plate in a manner that hot water and then cold water is continuously introduced through the platen,

wherein when the sheet is enclosed between the hot plate and the hydrostatic plate, a space around the sheet is sealed by a seal attached to the hydrostatic plate, air in the sealed space is vented, and the flexible top cover is flattened to enable controlled embossing of the sheet by the patterned protrusions.

2. A press module according to claim 1, wherein the hot plate and the mould have coefficients of thermal expansion which differ by at most 10%.

3. A compression module according to claim 1, further comprising a thin spacer layer between the hot plate and the die.

4. A press module according to any one of claims 1 to 3, wherein the hotplate has a thermal conductivity higher than 150W/m°k, a specific heat capacity lower than 250J/Kg ℃ and a specific heat capacity lower than 20-10 ^-6 Thermal expansion coefficient at m/mdeg.C.

5. A compression module according to claim 4, wherein the hot plate is made of tungsten copper alloy.

6. A press module according to claim 1, wherein the bore is sealed at an end of the bore to form a channel in fluid communication with the water supply through a vertical bore in fluid communication with the channel.

7. A press module according to claim 6, wherein the hot plate module further comprises at least one manifold connecting the water supply and the aperture and configured to deliver hot and cold water to and from the aperture.

8. A press module according to claim 7, wherein the hot and cold water circulate through the hot plate in a cross-flow configuration.

9. A press module according to any one of claims 1 to 8, wherein the platens further comprise a peripheral cooling zone, optionally in fluid communication with a cold water supply, and optionally separated from the central platen by a thermo-mechanical barrier.

10. A press module according to any one of claims 1 to 9, wherein the hydrostatic plate comprises a gap filled with oil, the gap being configured to flex the top cover by oil pressure provided by a spring unit in fluid communication with the oil in the gap, wherein the spring unit is configured to provide a pressure to flex the top cover prior to the embossing, and further configured to controllably reduce the pressure to flatten the top cover when the hotplate module is pressed against the hydrostatic plate.

11. A press module according to any one of claims 1 to 10, wherein the hydrostatic plate comprises a vacuum unit configured to vent air from the sealed space.

12. A press module according to any one of claims 1 to 11, further comprising pistons configured to press plates against each other to enclose the sheets between the plates and imprint the sheets, and to continuously move the plates away from each other to release the sheets.

13. A press module according to claim 12, further comprising a sheet release unit configured to separate the sheet from the hot plate after releasing the sheet.

14. A sheet embossing system, comprising:

the press module according to any one of claims 1 to 13, and

a sheet delivery system configured to deliver sheets to the press module.

15. A sheet embossing system as in claim 14, wherein the sheet is embossed on a continuous belt and the sheet delivery system is configured to continuously unwind and rewind the belt from respective rollers while continuously and stepwise delivering the sheet for embossing.

16. The sheet embossing system of claim 15, further comprising an unwind float unit and a rewind float unit configured to adjust continuous tape handling and step-wise continuous sheet delivery.

17. A sheet embossing system, comprising:

a press module, the press module comprising:

a platen module comprising a platen having a plurality of bores extending transversely therethrough and in fluid communication with water supplies of hot and cold water, wherein a contact side of the platen comprises a mold having patterned protrusions,

a hydrostatic plate comprising a flexible top cover configured to support a sheet as pressed against the patterned mold of the platen, wherein embossing of the sheet is performed by continuously heating and cooling the platen as the platen module is pressed against the hydrostatic plate in a manner that hot water and then cold water is continuously introduced through the platen,

wherein when the sheet is enclosed between the hot plate and the hydrostatic plate, a space around the sheet is sealed by a seal attached to the hydrostatic plate, air in the sealed space is exhausted, and the flexible top cover is flattened to enable controlled embossing of the sheet by the patterned protrusions, and

A piston configured to press plates against each other to enclose and emboss the sheet between the plates, and to continuously move the plates away from each other to release the sheet; and

a sheet delivery system, the sheet delivery system comprising:

an unwind roll having an associated unwind float,

a rewind roll having an associated rewind float, and

the feeder module is configured to receive the feed stock,

wherein the sheet delivery system is configured to continuously deliver tape from the unwind roll to the rewind roll while continuously and stepwise delivering a sheet of the tape for embossing to the press module.

18. A sheet embossing method comprising:

pressing a sheet on a belt between a hot plate and a hydrostatic plate to form a pattern on the sheet by a mold having patterned protrusions on the hot plate, wherein the pressing comprises:

sealing the sheet between the hot plate and the hydrostatic plate to form a sealed space, and exhausting air from the sealed space,

flattening the curved top cover of the hydrostatic plate to be flat and supporting the sheet, and

The sheet is embossed by heating and cooling the hot plate by continuously introducing hot water and then cold water through the hot plate.

19. The sheet embossing method of claim 18, further comprising releasing the embossed sheet and moving the belt to deliver a continuous sheet for pressing and embossing.

20. The sheet stamping method of claim 18 or 19, further comprising using hydraulic fluid to bend the top cover prior to receiving the sheet for stamping and to flatten the top cover after pressing the hot plate and the hydrostatic plate.