Method and apparatus for introducing a substrate into a nip - Patents.com

Abstract

A system for transferring a material pattern to a substrate is disclosed. The system includes a nip formed between a roller and an opposing surface, a web carrying the material pattern and traveling through the nip at a predetermined speed, and an endless conveyor transporting the substrate toward the nip. The substrate passes through the nip simultaneously with and at the same speed as the web so that the material pattern is transferred from the web to the substrate. Once the substrate is gripped in the nip, no further force is applied from the transport conveyor, thereby preventing compression of the substrate. The endless transport conveyor may be formed with at least one protrusion configured to engage with the trailing edge of the substrate. The endless transport conveyor may be configured to travel at a speed slower than the speed of the web to push the substrate toward the nip.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority under the Paris Convention to United Kingdom Patent Application No. 1915299.0, filed October 22, 2019, the entire contents of which are incorporated herein by reference as if set forth herein.

[0002] SUMMARY This disclosure relates to imparting a pattern of material to a substrate by transfer from a flexible web. [Background technology]

[0003] In the manufacture of certain products, it may be necessary to apply a material pattern to the surface of a substrate. For example, in the manufacture of solar cells, circuit boards, touch screens, and radio frequency identification (RFID) antennas, among others, it may be desirable to apply a material to a substrate that includes a composition including particles of a conductive material, a binder that typically maintains the particles in a desired shape (e.g., linear pattern, linear cross section, etc.), and / or an adhesive that can enhance adhesion to or facilitate any functional interaction with the target substrate. The substrate may be, for example, a semiconductor wafer in the case of solar cells, or an electrically insulating substrate in the case of printed circuit boards. Such substrates are generally rigid and planar, although flexible and / or non-flat (e.g., curved) substrates may also be used. In some cases, it may be desirable to apply the substrate pattern directly to a three-dimensional item, such as a portion of the body of the device, for example, in the case of RFID devices, and the surface to which the substrate pattern is applied may be flat or curved.

[0004] There are various known methods for imparting a material pattern to a substrate. Typically, the material pattern is formed directly on the substrate. In some methods, if the material pattern is not intended to cover the entire surface, selective deposition of the material may be performed to achieve the desired pattern, for example by screen printing. In other methods, the entire surface of the substrate may be coated with the material, and then parts of the material may be selectively removed, for example by etching or laser ablation, to leave the desired pattern. Each of these methods has advantages and disadvantages.

[0005] The applicant has previously proposed in WO 2018 / 020479 and WO 2018 / 020481 to form a material pattern on a substrate by first filling grooves formed in a flexible web with a material and subsequently transferring the pattern from the flexible web to the substrate. WO 2018 / 020483 discloses an apparatus for transferring a pattern of a composition comprising particles of a conductive material and a heat-activatable adhesive from a surface of a flexible web to a surface of a substrate, the apparatus comprising: (i) a transport mechanism for simultaneously advancing the web and the substrate into a nip having a pressure roller that presses the surfaces of the web and the substrate together; (ii) a heating station which heats at least one of the web and the substrate while the surfaces are in contact prior to or during passage through the nip to a temperature at which the adhesive in the composition becomes active; (iii) a cooling station for cooling the web and the substrate after passing through the nip; and (iv) a separation device for peeling the web from the substrate after it has passed the cooling station, leaving a pattern of the composition adhered to the surface of the substrate. Summary of the Invention [Problem to be solved by the invention]

[0006] When the above-described apparatus is used to transfer and print patterns onto a fragile (eg, thin and brittle) substrate such as a semiconductor wafer at high speeds, there is a risk that the substrate may be damaged or broken as it is fed into the nip. [Means for solving the problem]

[0007] In view of alleviating the above-mentioned problems, according to a first aspect of the present disclosure, there is provided a system for transferring a material pattern to a substrate, comprising: a web carrying the material pattern; a web running mechanism for running the web through a nip between a roller and an opposing surface; and a transport conveyor for advancing the substrate toward the nip so that the substrate is gripped in the nip and frictionally moves through the nip simultaneously and at the same speed as the web, wherein the web is pressed against a surface of the substrate as it passes through the nip, thereby transferring the material pattern from the web to the substrate, and when the substrate is gripped in the nip, no further force is applied from the transport conveyor to the substrate to advance the substrate toward the nip, thereby avoiding compression of the substrate.

[0008] In some embodiments of the system, the transport conveyor does not apply a force to the substrate in a direction that advances the substrate towards the nip, and the compression that is avoided is longitudinal compression of the substrate between the nip and the transport conveyor.

[0009] In some embodiments of the system, the transport conveyor has at least one protrusion that engages the trailing edge of the substrate, and the transport conveyor runs to advance the substrate toward the nip at a speed slower than the passage speed of the substrate through the nip, whereby the trailing edge of the substrate automatically disengages from the protrusion when the leading edge of the substrate engages in the nip.

[0010] A feed conveyor may be provided which deposits the substrates respectively in an amount drawn in by the protrusions of the transport conveyor such that the trailing edges of the substrates engage the protrusions of the transport conveyor and are thereby loaded onto the transport conveyor.

[0011] The role of the nip in the present invention is to apply a force pressing the web and the substrate against each other to ensure the transfer of the material pattern from the web to the substrate. The substrate is gripped in the nip without the force applied by the transport conveyor, which prevents the substrate from being compressed between the nip and the transport conveyor. Each side of the nip may be a roller (e.g., a pressure roller) or a low friction surface (e.g., an opposing surface) on which the substrate or web can easily slide relative to each other. In the embodiments of the invention described herein, at least the side of the nip that contacts the web is constituted by a roller.

[0012] When transferring material patterns from two different webs to both sides of a substrate, both transfers can occur simultaneously while the two webs and the substrate pass through the same nip, or the transfers can occur sequentially through two separate nips. In the former case, the nip can be formed by two opposing rollers, which in one embodiment are symmetrically sized.

[0013] According to a second aspect of the present invention, there is provided a method of introducing and running a substrate into a nip formed between a roller and an opposing surface, the substrate being advanced towards the nip by a transport conveyor configured to cease applying force to the substrate when a leading edge of the substrate engages in the nip so as to avoid compression of the substrate.

[0014] In some embodiments of this method, the transport conveyor is configured to cease applying a force to the substrate in a direction that advances the substrate toward the nip to avoid longitudinal compression of the substrate between the nip and the transport conveyor.

[0015] In some embodiments of this method, the transport conveyor is formed with protrusions for engaging with the trailing edge of the substrate to push the substrate towards the nip, and the speed of the transport conveyor is set to be slower than the speed at which the substrate passes through the nip, so that as the leading edge of the substrate enters the nip, the trailing edge moves away from the transport conveyor protrusions.

[0016] These and other advantages and features of the present disclosure, as particularly set forth in the appended claims, will be better understood by reference to the following detailed description taken in conjunction with the drawings.

[0017] Some embodiments of the present disclosure will now be further illustrated and described with reference to the accompanying drawings, in which like reference numerals or characters indicate the same or similar objects. The description, together with the drawings, will make clear to those skilled in the art how some embodiments of the present disclosure can be implemented. The drawings are for illustrative purposes and do not attempt to show structural details of the embodiments in more detail than is necessary for a fundamental understanding of the present disclosure. For purposes of clarity and explanation, some objects shown in the drawings are not necessarily drawn to scale. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 shows a transfer system as described in WO 2018 / 020483 for applying a (e.g., conductive) pattern to both sides of a substrate, which can be modified in accordance with the present teachings to include, in particular, a novel apparatus for delivering the substrate. [Diagram 2] FIG. 2 is a perspective view of a feed mechanism for delivering a substrate to a nip with precise timing and speed according to one embodiment of the present disclosure. [Diagram 3] FIG. 3 is a perspective cross-sectional view of the device shown in FIG. 2. [Figure 4] 3 is a perspective cross-sectional view of the device shown in FIG. 2 taken along a plane perpendicular to the cross section of FIG. [Diagram 5] 5A and 5B are schematic diagrams illustrating a nip through which a substrate can be delivered by a substrate feeding mechanism according to the present disclosure and a material pattern can be applied to one or more sides of the substrate. [Figure 6]FIG. 5B is a schematic diagram illustrating how the pressure roller and backing surface can be further coated and combined to form a nip, which can be implemented in conjunction with a substrate supply mechanism, particularly as illustrated in FIGS. 5A and 5B, in accordance with various embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] As described in more detail in WO 2018 / 020483, the apparatus of FIG. 1 is intended to impart a material pattern to the opposing surfaces of the substrate 10, for example as it is withdrawn from the stack 12 or from a cassette. For example, the material of the pattern may be a composition including particles, such as conductive particles (including, for example, metals or suitable alloys), and a heat-activated and / or pressure-activated adhesive (for example, a hot melt polyamide adhesive). Such a pattern may be made conductive, for example, by applying energy to sinter the composition. The composition may not require the application of energy to obtain electrical conductivity, and in some cases electrical conductivity is not required, for example, the pattern may be merely decorative. If the pattern is to be treated to develop its desired functional and / or aesthetic effect, for example, by heating to impart electrical conductivity or fusing or curing to improve adhesion to the substrate, such treatment is typically performed after the pattern is transferred from the web to the substrate.

[0020] Thus, in one example where a functional pattern capable of conducting electricity is considered, the substrate 10 may be a semiconductor wafer, and the apparatus applies the front and back electrodes of the desired final product (e.g., a solar cell) to the semiconductor wafer. The transferred patterns may constitute at least a part of the pattern desired on the substrate, which may for example form a grid-like pattern of solar cell fingers, with cross-directional bus bars applied separately, optionally by similar or different methods. The two conductive patterns applied on both sides are usually different from each other, but may each need to be precisely aligned with the substrate (and therefore may need to be mutually aligned on both sides of the substrate). In another example, the final product may be something other than a semiconductor wafer (e.g., an electrically insulating substrate, plastic, glass, etc.), have functionality other than a solar cell (e.g., functionality of a circuit board, RFID antenna, display, touch panel, etc.), and / or be purely decorative.

[0021] In the non-limiting example of a substrate transport mechanism shown in Figure 1, substrates 10 are removed one by one from the stack 12 to an inspection station 60 where their top surface can be optically analyzed for defects by a camera 601. A subsequent selection station 62 allows substrates found to be defective to be rejected.

[0022] The substrate 10 (preferably previously inspected to be free of defects) is advanced by a conveyor and alignment device 50 where it may be heated by a heater 52. Optionally, an adhesive configured to improve the transfer of the pattern from the web and / or its retention on the substrate may be applied to the surface of the substrate or a portion thereof. After being heated as required and precisely positioned and oriented, the substrate 10 (which may optionally be at least partially coated with adhesive) is fed into a nip 40 formed between two pressure rollers 22a, 22b. The pressure rollers 22a, 22b may be identical and symmetrical, as shown in FIG. 1.

[0023] Although it is recommended to have an inspection station 60 and a selection station 62 for detecting and rejecting defective substrates, such stations are not essential to the operation of the apparatus and are merely preferred from a quality control point of view. A similar station can optionally be provided downstream of the nip, for example after the peeling of the flexible web, in addition or alternatively to detect defect patterns and reject substrates having such defects and / or sort them into various bins according to their quality level.

[0024] If the apparatus has stations 60, 62 upstream of the nip, it may be desirable to further include an acceleration station 64 so that non-defective substrates drawn after defective and therefore ejected substrates can reach the nip in synchronism with the pattern of the web. Such an acceleration station 64 may thus prevent "empty" feed of the web at the nip in the event of a run out of substrates. However, such an acceleration station is not required, as such empty feeds may be tolerated or mitigated by alternative means, such as adding substrates preselected as defect-free from a buffer of such non-defective wafers.

[0025] Similar inspection stations may be located at other locations within the apparatus and configured to send relevant instructions to the system in response to the conditions they are intended to detect and signal. For example, in the event of a misfeed of the substrate, which may be detected by a sensor located upstream of the nip, the inspection station may cause an interruption of the substrate supply, a slowdown of the web supply, and a stop of operation of the apparatus (at least while the misfeeded substrate is removed).

[0026] The pattern of material containing the desired composition to be transferred to the substrate is carried by the two flexible webs 14a, 14b, which, as mentioned above, do not have to be identical. As can be clearly seen from Figure 1, the running mechanisms of the two webs 14a, 14b can be mirror images of each other, but this is not necessary and alternative configurations are possible, as illustrated in and described below with reference to Figures 5 and 6. To avoid repetition, unsuffixed reference numerals are used herein to generically refer to the components of both web running mechanisms, but in the figures the suffixes "a" and "b" are used to distinguish between the upper and lower running mechanisms.

[0027] Each web 14 is pulled, for example from a supply roll 16, by an idler roller 18 and a dancer 20 movable from left to right as indicated by arrow 21. The dancer 20 provides tension to the web and may also serve to ensure accurate registration 14 (edge ​​alignment) of the web pattern to the substrate 10. When two webs are used to apply material patterns to opposite sides of the substrate, tension rollers, which may be along each path, may serve to provide registration between the patterns carried by both webs.

[0028] Typically, when the web 14 is unwound from the supply roll 16, the composition is level with the surface of the web and is usually, but not necessarily, essentially dry. Optionally, an adhesive configured to improve the transfer of the pattern from the web and / or its retention on the substrate can be applied to the web 14 after it is unwound from the supply roll 16 and before it contacts the substrate (e.g., upstream of the nip). The web 14 passes between two pressure rollers 22, forming a nip 40, into which the substrate 10 is fed. In the nip 40, the substance / composition pattern of the web 14 is pressed against the surface of the substrate 10, so that the substance / composition pattern adheres to the substrate. The web 14 then passes through an optional cooling station 23, passes between two rollers 26, and can be separated from the substrate 10, for example, by a separation device 30 or by forming a winding angle suitable for separation. After separation from the substrate 10, for example, by the device 30, the web can be rewound on a winding roll 32. If desired, the take-up roll 32 can be returned to the web supplier for recycling.

[0029] If the take-up roll 32 is discarded, the web 14 may be referred to as a disposable web or a flexible film. Processes using webs such as those disclosed herein may be referred to as "roll-to-roll" processes, in which the web, upon which the pattern is transferred to the substrate, is unwound from the supply roll 16 and rewound on the take-up roll 32.

[0030] If peeling is not desired, for example, when the web 14 may serve to further protect the substrate 10, the separation device 30 and take-up roll 32 may be omitted from the apparatus. The term "transferred" as used herein with respect to the composition pattern and variations thereof should be understood to encompass embodiments in which the web and substrate are not separated from one another. If cooling is not desired, for example, because the material pattern is transferred by pressure, the transfer is not performed at a high temperature, and / or the web does not need to be rapidly separated from the substrate, the cooling station 23 may be omitted from the apparatus or turned off.

[0031] An optical sensor 70 may be provided to sense the position of the pattern on the web 14, for example upstream of the idler roller 18, for the purpose of ensuring accurate registration of the material / composition pattern on the substrate 10. The types of sensors, their positioning along the path followed by each web and substrate, the signals they may provide to systems configured to control and respond, and the responses they may cause to various parts of the apparatus to ensure accurate registration or reduce misregistration to within acceptable limits, are known to those skilled in the art and need not be detailed herein.

[0032] As a non-limiting example, the controller may set a first speed for the web and adjust a second speed for the substrate on the transport conveyor when (and before) the substrate engages the nip. The peripheral speed of at least one pressure roller of the nip is essentially the same as the linear speed of the web, so that when comparing the speed of the substrate and the speed of the nip, the respective corresponding linear speeds are referred to. The applicant avoids compression of the substrate, particularly in the longitudinal direction, by ensuring that the speed of the nip is higher than the speed of the substrate when engaging the nip. This can be achieved by increasing the speed of the web relative to the substrate or decreasing the speed of the substrate relative to the web.

[0033] Although the drawings show a schematic apparatus capable of transferring two patterns simultaneously to respective opposing surfaces of a substrate, one skilled in the art will readily appreciate that a similar apparatus can be provided to transfer a substance / composition pattern to only one side of a substrate or to each side of the substrate (e.g., two nips are required to sequentially apply the pattern of a first web to a first side and the pattern of a second web to a second side). In such a case, a nip 40 can be formed, for example, between one pressure roller 22 and a backing support 34 for the substrate 10, whether the nip is the single nip of the apparatus or the first or second nip. The backing support can be static (e.g., a plate, pressure roller, and / or a web moving to displace the substrate thereon) or moving (e.g., a conveyor configured to transport the substrate at a speed selected to match the relative movement of the respective webs). Because the nip includes at least one pressure roller 22 (e.g., 22a), the surface against which pressure is applied can be referred to as the opposing or backing surface 36, which may be a second pressure roller (e.g., 22b) or backing support 34 as described above, and can provide a static or dynamic surface as the nip closes in operation of the system.

[0034] Figures 5A and 5B are highly schematic diagrams showing several configurations of nips. Figure 5A shows a system in which a substrate 10 is fed into a nip 40A in the direction of the arrow, and both sides of the substrate 10 are provided with a material pattern realized by webs 14a, 14b, respectively. The webs 14a, 14b are fed by feed rolls 16a, 16b, respectively, and eventually rewound on take-up rolls 32a, 32b. The substrate 10 is fed into the nip 40A formed by the two pressure rollers 22a, 22b via a feed mechanism 55, which will be described in more detail below, and exits the nip as 10' after transfer of the pattern.

[0035] FIG. 5B shows an alternative system in which the substrate 10 is fed into the nip 40B in the direction of the arrow, and one of the two sides of the substrate 10 is provided with a material pattern realized by a web 14a. The web 14a is fed by a feed roll 16a and rewound on a take-up roll 32a. The substrate is fed into the nip 40B formed by the pressure roller 22a and the backing support 34 via a feed mechanism 55a. The substrate may optionally continue to enter a second nip 40C formed by the pressure roller 22b and the backing surface 36 via a feed mechanism 55b. The nip 40C allows a second material pattern to be applied to the other side of the substrate. The second pattern is realized by a web 14b fed by a feed roll 16b and rewound on a take-up roll 32b. Nips 40A and 40B are examples of nips 40C, the configuration of which may be suitable for synchronously applying material patterns to both sides of the substrate. However, all three configurations can be used to impart a pattern to only one side of a substrate, or to impart patterns sequentially, one side at a time.

[0036] Regardless of the nip configuration, the pressure roller 22 and backing surface 36 (e.g., backing support 34) that comprise the nip 40 can be configured in a manner appropriate for the web and substrate intended to pass therebetween. For example, they can be appropriately gapped, have appropriate dimensions, shapes or surface configurations, appropriate frictional characteristics, appropriate compressibility (e.g., to promote intimate contact between the web and substrate surfaces), appropriate hardness (e.g., to match the mechanical properties of the substrate), and similar considerations that would be readily appreciated by one of ordinary skill in the art. Such characteristics of the pressure roller or backing support can be inherent to the part or can be achieved by an appropriate coating thereon.

[0037] In some embodiments, the pressure roller 22 (or its backing support) can be coated with a substance (e.g., a polymeric compound or mixture) to form an outer layer 25 on its outer surface having a hardness of 100 Shore A or less, 90 Shore A or less, 80 Shore A or less, 70 Shore A or less, 60 Shore A or less, 50 Shore A or less, or 40 Shore A or less. In some embodiments, the outer surface hardness of the pressure roller 22 is at least 10 Shore 00, at least 30 Shore 00, at least 50 Shore 00 (which corresponds to approximately 10 Shore A), at least 20 Shore A, or at least 30 Shore A.

[0038] In some embodiments, the pressure roller 22 (or its backing support) can be coated with a substance to form an outer layer 25 on its outer surface that alternatively or additionally functions as a compression layer configured to ensure proper contact with the surface of the web and substrate.

[0039] 6 is a schematic diagram of such an alternative, where the pressure roller 22 or backing surface 36 is uncoated or coated with an outer layer 25. For these possible combinations illustrated by nips 401-407 in the figure, the coated versions of the pressure roller and backing surface are designated 22' and 36', respectively.

[0040] The parts forming the nip (e.g., the pressure roller 22 and the backing surface 36) are preferably removable from one another so that the distance between them can be adjusted (e.g., moving at least one of the two pressure rollers 22a, 22b closer to or further away from the other), for example to adapt the nip gap to the thickness of the substrate and / or web, to thread the web or to remove misfed substrates, as well as for conventional operation and maintenance that may be required at the nip.

[0041] Closing the nip to form a gap suitable for transfer may cause a slight (typically backward) displacement of the web in contact with the moved portion, and this phenomenon may be taken into account and the web may be appropriately positioned before closing. For example, one of the two webs 14 may be intentionally advanced relative to the other before closing the nip 40 so that the patterns carried by the webs are misaligned with each other, so that the webs and their respective patterns are accurately aligned (e.g., within a tolerance) when the nip is closed. To achieve accurate alignment after nip closure, the degree of intentional misalignment before nip closure may be calculated based on the structure and operation of the nip or may be empirically determined. Accurate alignment after nip closure may be visually confirmed before starting or reactivating the web running mechanism or with the aid of suitable sensors during operation of the device.

[0042] In the cooling station 23, cooling of the substrate with the web still attached is performed by an endless belt 24, which in the illustrated example passes through a nip between rollers 22 and 26, and further through an idler roller 28. Other cooling methods and devices may alternatively be used for such purposes. In some such methods and devices, roller 26 may be omitted. In an alternative method, the web (and thus to some extent the substrate) may be conductively cooled by thermal contact with a "static" heat sink (e.g., a conventional heat exchanger passively or actively cooled by a fluid, and optionally including a number of fins to facilitate heat dissipation). For example, the heat sink may extend between the nip and a point on the path where the web is separated from the substrate (e.g., by a separation device or by forming an angle sufficient for the web to separate from the substrate). The web(s) and / or substrate may be maintained in thermal contact with the heat sink by one or more rollers that facilitate such contact. In some embodiments, these rollers may also act as part of the heat sink. For example, such rollers may optionally be cooled (eg, liquid cooled).

[0043] Regardless of the means and methods used to cool the web(s) and / or substrate, such cooling is configured so that the web reaches the separation point (e.g., separation device) at a certain temperature to facilitate separation of the web from the substrate and / or attachment of the composition pattern to the surface of the substrate. Without wishing to be bound by a particular theory, it is believed that separating the web from the substrate at a temperature below the softening temperature of the web and below the softening temperature of the composition (e.g., below the softening temperature of the polymer, e.g., adhesive, especially the thermally activated adhesive, contained in the composition) will aid in these steps. For example, the temperature of the web after cooling and at the time of separation can be up to 60°C, up to 50°C, or up to 40°C.

[0044] Following this rationale, a cooling station may not be necessary in some embodiments of the apparatus. For example, if the transfer is performed at a relatively moderate temperature that allows the pattern to be sufficiently transferred and adhered to the substrate, a cooling step may not be necessary. This may be the case, for example, if the adhesive of the composition is a pressure sensitive adhesive, or if additional adhesive is applied to the substrate, web, or selected areas thereof.

[0045] When using the apparatus shown in FIG. 1 at high speeds, damage (e.g., breakage) has been observed at a commercially significant rate when the substrate 10 is thin and brittle. Breakage of relatively fragile substrates can be reduced or prevented by uniform slowing down of the apparatus, but such an approach also reduces productivity. The present disclosure provides an alternative feeding mechanism intended to replace the corresponding components upstream of the nip 40 to achieve a lower breakage rate, preferably less than 1.5%. Although the feeding mechanism of the present invention is advantageous for relatively fragile substrates, its application need not be limited to such substrates. The transfer of the pattern at a relatively high speed increases productivity regardless of the type of substrate. The apparatus downstream of the nip 40 can be, for example, essentially as described in WO 2018 / 020483 and US 2019 / 0174635, which may be retained unchanged or adapted as described herein.

[0046] Similarly, components upstream of the nip that only facilitate or are not related to the operation of the alternative feeding mechanism according to the present teachings may be retained. For example, a subsystem that ensures the timely realization of the pattern carried by the flexible web may be similar in principle and configuration to those previously disclosed by the applicant, or may be otherwise partially known from the art, or may be adapted as further described herein. Such known components will not be described in detail here, but the interested reader is referred to, in particular, WO 2018 / 020483 and US 2019 / 0174635, which are incorporated by reference in their entirety as set forth herein. Novel configurations are described in the following paragraphs.

[0047] 2 to 4 show a device 56 for feeding substrates 10 to the nip 40 between the two rollers 22a, 22b as described above. This device is constituted by two separately running conveyors, referred to herein as a feed conveyor 54 and a transfer conveyor 58 to distinguish them from each other. The role of the feed conveyor is to transport the substrates 10 one by one from a suitable supply, such as a stack or a cassette, to a position where they can be picked up by the transfer conveyor 58. The role of the transfer conveyor 58 is first to ensure accurate positioning of each substrate 10 (for example by a position detection sensor) and then to advance the substrates 10 to the nip 40 at a predetermined speed so that the substrates 10 arrive at the nip 40 in synchronism with the movement of the web carrying the substrate pattern, thereby achieving accurate registration of the pattern with the substrate.

[0048] As will be readily appreciated by those skilled in the art of registering patterns on surfaces or with each other, there is usually some tolerance in such matters, which may be expressed in relative terms (e.g., percentage of deviation) or absolute terms (e.g., distance from intended positioning). For example, for functional patterns, registration may be considered accurate if it is within a tolerance of ±100 μm or less, ±75 μm or less, or ±50 μm or less from accurate positioning. For example, a pattern is accurately registered if it is within ±50 μm of the desired positioning relative to the various edges (leading, trailing, right, and left edges) of the substrate in each of the X direction (the direction of movement of the conveyors 54, 58) and the transverse Y direction. Also, if patterns are applied to both the top and bottom surfaces of the substrate, the patterns are accurately registered if they are within ±50 μm of the desired positioning relative to each other in each of the X and Y directions. For purely decorative patterns, such tolerances may be further relaxed, and a pattern applied within a few millimeters (mm) of its intended location may be considered to be accurately registered if it is visually pleasing for its desired decorative purpose.

[0049] The speed of the feed conveyor 54 is controlled via an electric motor, and the speed is monitored using an encoder. The feed conveyor 54 may have two spaced apart cyclically movable endless belts running parallel to one another, with each side edge of the substrate 10 supported on a respective one of the two belts. As such, the belts are preferably spaced apart by a distance less than the width of the substrate 10 being transported. The substrates 10 may be delivered to the feed conveyor 54 by withdrawing the substrate 10 from a stack or cassette, or by another station upstream of the feed conveyor 54.

[0050] The reason why the supply conveyor 54 is formed by two separate belts is that at its downstream end, the two belts straddle the upstream end of the transport conveyor 58, forming an overlapping area where the respective substrates are transferred from the supply conveyor 54 to the transport conveyor 58. The transfer between the conveyors is described in more detail below in relation to an embodiment in which the supply conveyor is in a higher plane than the plane of the transport conveyor and the substrates descend from the former to the latter, respectively. Those skilled in the art will know how to modify the apparatus for the reverse case in which the supply conveyor is in a lower plane than the plane of the transport conveyor and the substrates ascend from the former to the latter, respectively.

[0051] In some embodiments, one or more of inspection, sorting, laser doping, or other processes may be performed on the substrates 10 while they are on the infeed conveyor 54. In other embodiments, the infeed conveyor 54 functions purely as a means to transfer the substrates 10 from a stack or cassette to a transfer station, generally indicated at 56.

[0052] The transfer station 56 comprises a transfer conveyor 58. The transfer conveyor 58 is formed as an endless belt with at least one projection 66, shown in FIG. 3 as a bar 66 extending laterally across the entire width of the belt, for example. However, it may have any other dimensions to suit the size and / or intended location of the substrate. For example, the projection may have the shape of a pin located across the width of the conveyor and suitable for contacting the substrate, and such projection may optionally facilitate registration of the substrate to the nip. The projection is intended to engage the trailing edge of the substrate 10 advancing towards the nip 40. Since the substrate advances by being pushed from its trailing edge, rather than relying on the friction of the conveyor, each substrate is accurately positioned as it advances towards the nip 40. The transfer conveyor 58 may be dimensioned to have only a few projections (e.g., two or three) around its entire circumference, so that only one entire substrate 10 can be transported towards the nip 40 at a time. This may be desirable for a number of reasons, including preventing registration between one substrate 10 and the web from affecting the next substrate, and minimizing loss of substrates in the event of a shutdown.

[0053] In the exemplary illustrated embodiment, the plane of the supply conveyor 54 is higher than the plane of the transport conveyor 58, but this should not be interpreted as limiting. In the overlapping area, the substrate is run by the supply conveyor over a lift mechanism 68 (best seen in Figures 3 and 4). The lift mechanism 68 supports one substrate at its edge in a plane higher than the plane of the transport conveyor 58. Once a substrate 10 is loaded by the supply conveyor 54, the lift mechanism 68 lowers the supported substrate to a position above the plane of the transport conveyor where it can contact the protrusions 66 of the transport belt. As a result, the substrate 10 slides on the belt of the transport conveyor 58 away from the lift mechanism 68 with its rear edge in contact with the protrusions 66. The lift mechanism 68 moves synchronously with the transport conveyor 58 so as to move to a lower position only if there are no protrusions below. This can be accomplished, for example, by operating the lifting mechanism 68 via a cam that rotates in sync with the conveyor belt, or by initiating the descent of an independently driven lifting mechanism 68 via a sensor associated with the conveyor 58.

[0054] To reduce the chance of the substrate 10 coming into contact with the bars 66 and being damaged, the frame of the lifting mechanism 68 on which the substrate rests may have a low coefficient of friction. This can be achieved by using bearing members, treating or coating the lifting mechanism 68 with a low friction material, or simply polishing the frame of the lifting mechanism 68.

[0055] The speed of the web 14 and the speed of the transport conveyor 58 may be varied to synchronize the pattern of the substrate 10 and the web 14. Sensors may be installed at the transport station 56 to monitor the position of the protrusions 66 and / or the substrate 10, particularly its leading edge. When two webs are used to apply a pattern to opposing surfaces of the substrate 10, at least one of the webs may run at a constant surface speed. The speed of the transport conveyor 58 is lower than the surface speed of the web(s) at the nip 40 to ensure that the substrate 10 is pulled away from the protrusions 66 when the leading edge of the substrate 10 contacts the nip 40. If the speed of the transport conveyor 58 exceeds the speed of the substrate passing through the nip 40, the protrusions 66 may exert a longitudinal compressive force on the substrate, which may increase the risk of breakage. Thus, as can be easily understood, the present teachings are directed to an apparatus (and associated methods) in which there is no force from the transport conveyor that would cause compression on the edge of the substrate when the leading edge of the substrate is gripped in the nip. The edges of the substrate along the X and Y directions are typically more fragile than portions closer to the center of the substrate, and therefore the apparatus of the present invention maintains its integrity and may be sturdy enough to allow the substrate to undergo compression in the Z direction that is large enough to ensure transfer but small enough to prevent breakage, or may be configured to apply a nip that applies compression in the Z direction that is large enough to ensure transfer but small enough to prevent breakage, or both.

[0056] Precise alignment in the X direction between the pattern carried by the web and the substrate to which it is transferred is achieved by precisely timing the movement of the transport conveyor. Alignment in the cross Y direction can be achieved by urging the substrate in the cross direction while it is on the transport conveyor 58. The trailing edge of the substrate positively engages the transport conveyor protrusions 66 so that the Y alignment action does not interfere with the position of the substrate in the X direction.

[0057] If the projections 66 of the transport conveyor contact the trailing edge of the substrate at more than one point, and the members that press the substrate against the guide for Y-alignment also contact the side edges of the substrate at more than one point, the substrate may be skewed (rotated about a vertical axis) during Y-alignment. To ensure that the substrate arrives at the nip facing the desired direction, the projections 66 preferably only make point contact with the trailing edge of the substrate, and two or more pushers are preferably disposed on one side of the transport conveyor to bias the substrate against an elongated guide surface disposed on the other side of the transport conveyor. The guide surface may be a solid bar having a low friction surface, or a series of rollers in sufficient proximity to each other (e.g., in rolling contact) to form an elongated guide surface. The pushers may be spaced from each other in the direction of substrate travel, and may include rollers that are biased toward the substrate by a spring. The spacing of the pushers and the timing of their contact with the side edges of the substrate are configured to prevent the pushers from contacting relatively fragile corners of the substrate. Engagement and disengagement of the substrate with the pusher can be controlled by a cam system referenced to the position of the substrate along the X direction.

[0058] This arrangement allows one side of the board to have two contact points with the guide surface and only one contact point with the transfer conveyor protrusion. This avoids the risk of the board skewing that would occur if there were only three contact points. The pusher facilitates registration of the board in the Y direction, while the protrusion contributes to registration of the board in the X direction, both relative to the nip.

[0059] When applying a pattern to one side of the substrate, registration of the web to the nip is not necessary if proper substrate registration ensures proper transfer timing and therefore positioning of the pattern to one side of the substrate. However, tension rollers along the path of the web can facilitate such alignment between the substrate and the transferred pattern. When transferring patterns from two webs to both sides, in two successive nips, or more typically in the same nip, tension rollers along the path of the web are necessary on at least one of the two webs to ensure proper alignment. Tension rollers along each of the paths of both webs can further facilitate the process.

[0060] It should be noted in this context that due to the stiffness of certain substrates, particularly semiconductor wafers, even when a straight edge of the substrate is pressed against a straight guide, there are likely only two contact points through which force can be transferred from one to the other.

[0061] If the substrates were simply transferred between the supply and transfer conveyors at random times, there would be a risk that the substrate would become stuck, at least partially, on one of the protrusions 66 in the overlap area of ​​the two conveyors. The lift mechanism 68 described above is designed to protect against this. The lift mechanism keeps each substrate clear of the protrusions 66 and lowers the substrate in sync with the movement of the transport belt 58 to ensure that the substrate can be moved past the next protrusion and through the lift mechanism.

[0062] The use of a lifting mechanism is only one way to overcome the problem of the speed difference between the supply conveyor and the transfer conveyor while ensuring that the protrusions contact the trailing edge of the substrate. In an alternative embodiment, an overlapping area may be provided between the two conveyors 54, 58, and a friction member of the transfer conveyor may engage and slow down the substrate 10 transferred from the supply conveyor 54 to the transfer conveyor 58, ensuring that the protrusions 66 of the transfer conveyor 58 contact the trailing edge of the substrate. Precise timing of the two conveyors 54, 58 can prevent the substrate being transferred from landing on the protrusions. Proper timing ensures that the substrate is fed (placed on the transfer conveyor) in the amount that is drawn in by the protrusions, respectively.

[0063] The distance between protrusions along the X-length of the conveyor belt must be sufficient for the friction members / lifting mechanisms to function properly, and the distance between the protrusions that sandwich the feed volume must be at least 10% greater than the dimensions of the substrate.

[0064] The lift mechanism also prevents the substrate above it from being affected by the registration of the substrate on the transport conveyor, by simply lowering the substrate before its leading edge enters the nip, as described above, which is a key advantage of the lift mechanism over the friction members.

[0065] A presence detection sensor may be provided between the supply conveyor and the transfer conveyor to initiate movement of the transfer conveyor 58 when a substrate is detected on the supply conveyor 54. The presence detection sensor may be used to adjust the speed of the supply conveyor 54 to ensure that the substrate is delivered to the transfer conveyor 58 at the appropriate time (e.g., with respect to the position of a protrusion that may engage the trailing edge of the substrate transferred from the supply conveyor to the transfer conveyor). Additional sensors may be provided to assess the registration of the substrate with respect to the nip and to synchronize the arrival of its leading edge with the desired positioning of the pattern to be transferred from the web.

[0066] Lift mechanism 68 may be a cam and follower mechanism, a piston mechanism, or other mechanism known in the art.

[0067] Alternatively, or as a secondary constraint, a system (not shown) may be installed further downstream to straddle the transfer conveyor 58. Such a system may have one or more guide rails to accurately align the substrate 10. If installed in addition to the pusher used to facilitate alignment of the substrate in the Y direction, the guide rail(s) may be located upstream of the pusher to provide preliminary alignment.

[0068] The transfer station 56 may further include a heater 52 which serves to heat the substrate 10 to a desired temperature before it enters the nip. Similarly, heaters may be positioned along the path of the web to increase its temperature before contacting the substrate. Alternatively, or additionally, if an adhesive coating is applied to the substrate or web, or selected areas thereof, and the adhesive used in such coating is heat-activatable (optionally in addition to being pressure-activatable), a heater may be positioned downstream of an applicator configured to apply the adhesive coating.

[0069] The desired temperature at any of these locations may be a temperature that will activate the adhesive in the composition carried by web 14, for example, if the composition includes a heat-activated adhesive, and need not be the same for the substrate and each web. Suitable heating temperatures will depend on the nature of the composition and adhesive, as well as the materials that make up the webs and substrate, and are described in more detail in WO 2018 / 020479 and U.S. Patent Application Publication No. 2019 / 0172967. For example, the heating temperature may depend on the softening temperature of the composition and adhesive therein, and therefore may be different on each side of the same substrate, optionally with patterns having different materials and / or arrangements thereof being applied from each web. In embodiments where heaters are used, care must be taken to configure any necessary apparatus and portions thereof (e.g., portions in contact with or adjacent to the heated web and / or heated substrate) to withstand the heat without distortion or failure.

[0070] Heating can take different forms depending on the temperature to be reached and can be by conduction, convection, or radiation. The web is typically heated using hot air or by contact with a heating member (e.g., a heated roller), if necessary, although it can also be heated by radiation, as described below for the substrate.

[0071] In embodiments in which the substrate is heated by radiation, the heater 52 may comprise one or more infrared lamps disposed above and / or below the transfer conveyor 58. If the substrate 10 is thick, e.g., greater than about 1 mm, heat lamps disposed on both sides of the substrate 10 may be used together to achieve uniform heating. If such heating is required, the transfer conveyor 58 may be split in the same manner as the supply conveyor 54, i.e., comprised of two thin synchronous belts, each supporting one side of the substrate, each having respective protrusions for pushing the substrate 10 from both sides.

[0072] In some embodiments, the infrared lamps included in heater 52 can be configured to collectively radiate approximately 6 kW, 12 kW, 24 kW, or other suitable amount of radiation. A shield 74 may be provided to prevent radiation from the lamps from reaching outside the heated area. A cooling device 76 may be provided to prevent overheating of the shield. The cooling device may include an air-cooled component or other means known in the art.

[0073] Heating can be performed on the web(s) and / or substrate upstream of the nip, but alternatively or additionally at the nip. For example, the pressure roller 22 can additionally function as a heating roller in some embodiments. Heating the web and / or substrate upstream of the nip may eliminate the need for heating the nip or allow the nip to be heated to a lower temperature. In some embodiments, heating can even be performed before the transfer station 56, but the closer the heating is performed to the nip 40, the more efficient the process. When performed at multiple locations and / or for one of multiple substrates or webs, the various heating temperatures can be set so that the temperature gradually changes as the substrate and / or web advance to the nip. Such gradients can be selected to avoid sudden increases in temperature, or conversely, sudden decreases in temperature, which may adversely affect the transfer of the pattern from the web to the target surface of the substrate. Temperature sensors may be incorporated into the apparatus to ensure that the temperature is within an acceptable range, and a controller (manual or computer controlled) may be provided to maintain the temperature within the respective acceptable range.

[0074] As mentioned above, in some embodiments, only one substrate 10 can be placed on the transfer conveyor 58 at a time so that waste is minimized if a shutdown occurs. For example, if a shutdown occurs while a substrate 10 is passing through a heater, the substrate may be considered waste if it is only partially heated and then cooled, or if it is overheated due to the conveyor 58 stopping in the heating zone. This can be mitigated by using a shutdown procedure in which each station shuts down sequentially as it passes the last substrate 10 to the next station. For example, the transfer station 56 may only shut down when the leading edge of the last substrate 10 enters the nip 40. In such a case, the few substrates rescued from irreversible processing by this sequential shutdown do not need to be wasted and can be recycled.

[0075] After passing through the nip, the web can be separated (e.g., peeled) from the substrate, and when such separation occurs, the transfer of the material pattern from the web to the substrate is complete. To aid in the separation, the substrate and web(s) may be cooled downstream of the nip. It is believed that cooling can accelerate or otherwise facilitate the attachment of the material pattern to the substrate and / or facilitate the transfer of the pattern from the flexible web, and therefore the appropriate cooling temperature and / or cooling rate will vary depending on the nature of the composition and its components. Regardless of the means used to ensure cooling of the substrate and / or web, the location and / or device where such cooling is performed as required can be referred to as a cooling station.

[0076] The separation device 30 of the illustrated exemplary embodiment of the apparatus has a metal plate bent at a small radius defining an acute angle. The web bends at the acute angle defined by the outside of the bent metal plate on its return path to the take-up roller 32. This action causes the web 14 to peel off from the substrate 10, leaving the composition adhering to the substrate 10. Those skilled in the art will readily appreciate that a similarly satisfactory peeling of the web 14 can be achieved by an angle formed between the path of the web 14 and the path of the substrate 10, or by an alternative separation device. Regardless of the means used to ensure the peeling of the web from the surface of the substrate, the location and / or device where such a separation is performed as required can be referred to as a separation station. The cooling station and the separation station are non-limiting examples of stations downstream of the nip where the substrate and the web can be subjected to any desired action, these stations are also referred to as post-transfer stations.

[0077] The substrate, now with at least a portion of the desired pattern formed on at least one side, can be further processed if necessary. For example, it can be exposed to a sufficient amount of energy to cause sintering and / or fusion of metal particles contained in the material to impart electrical conductivity to the transferred pattern, and can be hardened by radiation if the material contains a hardenable material that can promote adhesion to the substrate. If the web is not peeled from the substrate, processing following the nip can include separating the individual substrates (e.g., by cutting the web between adjacent substrates) that would otherwise be attached to the common web and "joined". Such post-processing can be performed offline in a separate apparatus (e.g., a solar cell furnace) or in-line using an apparatus according to the present teachings. Depending on the substrate, the transferred pattern, and the intended use, there are various post-processings that are known to those skilled in the art and will not be described in detail herein. The location or device where such post-processing of the substrate and the web can be performed, whether still attached to each other or separated, can be called a post-processing station. A post-processing station can be considered a type of post-transfer station.

[0078] Although the present disclosure has been described with reference to various specific embodiments thereof, such specifically described embodiments are for purposes of illustration only and should not be construed as limiting.

[0079] Therefore, it should be understood that the above description, including the specifically described devices, is merely an example of the subject matter described herein, is described merely for illustrative purposes, and is therefore not necessarily intended to be limiting. Moreover, all examples, embodiments, implementations, instances, illustrations, illustrations, etc. of such features described herein should be understood to be non-limiting. Based on the disclosure herein, many other alternatives, changes, modifications, substitutions, and variations of such features will occur to those skilled in the art. Therefore, all such alternatives, modifications, and variations, and any changes that are within the meaning and scope of equivalence thereof, are intended to be embraced.

[0080] As used herein, the word "exemplary" is used to mean "serving as an example, instance, or illustration." Any example, embodiment, instance, illustration, or illustration of a particular feature described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments, nor does it exclude the incorporation of one or more features from other embodiments, or both. Moreover, features described as preferred or advantageous in one embodiment are not necessarily preferred or advantageous in other embodiments.

[0081] It should be understood that certain features of the subject matter described herein that are described for clarity in the context of various embodiments can be implemented in a single embodiment or in combination in multiple embodiments. Conversely, various features of the subject matter described herein that are described for brevity in the context of a single embodiment or multiple embodiments can be implemented individually or in any suitable subcombination, or in any other embodiment of the subject matter described herein, as appropriate. Certain features described in the context of an embodiment are not considered essential features of an embodiment unless the embodiment is inoperable without those features.

[0082] Unless otherwise defined or understood from the present disclosure, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0083] Unless otherwise stated, the use of the expression "and / or" between the last two elements of a list of alternatives indicates that one or more of the listed alternatives are appropriate and possible.

[0084] In the description and claims of this disclosure, the verbs "comprise," "include," and "have," as well as their conjugations, are used to indicate that the subject or object of the verb is not necessarily an exhaustive list.

[0085] As used herein, the singular forms "a," "an," and "the" include plural references and mean "at least one" or "one or more," unless the context indicates otherwise.

[0086] As used herein, the term A and / or B is intended to mean either A or B, and in some embodiments may mean both A and B.

[0087] Positional or dynamic terms such as "upper", "lower", "right", "left", "bottom", "back", "front", "lower", "down", "lower", "upper", "upper", "higher", "vertical", "side", "horizontal", "rear", "forward", "upstream", and "downstream", and grammatical derivatives thereof, are used herein for descriptive purposes only and may be used to describe the relative positioning, location, or displacement of certain objects (e.g., components of an apparatus), to indicate a first object or a second object, or both. Such terms do not necessarily indicate, for example, that an object "below" is lower than an object "above". Such orientation or components, or both, may be flipped, rotated, moved in space, positioned at an angle or diagonal, positioned horizontally or vertically, or similarly altered.

[0088] When limits of ranges for features of embodiments of the present disclosure are set forth herein, it should be understood that, unless otherwise stated, possible values ​​of such features in embodiments can include the set forth limits as well as values ​​between the set forth limits. In this specification, unless otherwise stated, adjectives such as "substantially," "approximately," and "about" modifying a condition or relationship characteristic of one or more features of embodiments of the subject matter described herein should be understood to mean that the condition or characteristic is defined within a tolerance allowed for operation of the embodiment for its intended use, or within an expected variation from measurements being made and / or the measuring equipment being used. For example, when the terms "about" and "approximately" precede a numerical value, it can indicate only ±15%, or ±10%, or ±5%, or any other suitable ± variation within such range, and in some cases, can indicate a precise value. Additionally, unless otherwise noted, terms (e.g., numerical values) used in the embodiments of the subject matter described herein should be construed as having a latitude that may depart from the strict meaning of the associated term, even without such adjectives, but that enables the embodiment or associated portions thereof to operate and function as described and / or understood by one of ordinary skill in the art.

[0089] To the extent necessary to understand or carry out the contents of this disclosure, all publications, patents, and patent applications mentioned herein, including specifically applicant's applications, are hereby incorporated by reference as if set forth herein in their entireties.

[0090] In addition to the features of the above disclosure as claimed in the accompanying claims, features which are believed to be inventive in their own right are set out in the following clauses in order to provide a justification for the filing of any one or more divisional patent applications.

[0091] Item 1. An apparatus for transferring at least one material pattern from a respective surface of at least one web to at least one surface of a substrate, the apparatus comprising: a nip through which the substrate passes simultaneously with the at least one web, the nip having at least one pressure roller serving to press the surface of the at least one web and the surface of the substrate against each other as they pass through the nip; a web supply mechanism; and a substrate transport mechanism, the operation of which is synchronized to ensure accurate positioning of the material pattern on the substrate surface.

[0092] Item 2. An apparatus for transferring at least one material pattern from a respective surface of at least one web to at least one surface of a substrate, the apparatus comprising: a nip through which the substrate passes simultaneously with the at least one web, the nip having at least one pressure roller serving to press the surface of the at least one web and the surface of the substrate against each other as they pass through the nip; a web feed mechanism; and a substrate transport mechanism, the substrate transport mechanism including an alignment mechanism for ensuring accurate positioning of the substrate in a direction transverse to the direction of movement towards the nip.

[0093] 3. The apparatus of claim 2, wherein the alignment mechanism further serves to ensure accurate orientation of the edge of the substrate relative to the nip.

[0094] Clause 4. The apparatus of clause 3, wherein the alignment device is configured to laterally bias the substrate such that an edge of the substrate contacts three reference points, at least one of the reference points contacting a trailing edge of the substrate.

[0095] Item 5: An apparatus for transferring at least one material pattern from a respective surface of at least one web to at least one surface of a substrate, the apparatus comprising: a nip through which the substrate passes simultaneously with the at least one web, the nip having at least one pressure roller serving to press the surface of the at least one web and the surface of the substrate against each other as they pass through the nip; a web supply mechanism; and a substrate transport mechanism, the substrate transport mechanism having a supply conveyor, a transport conveyor disposed downstream and below the supply conveyor, and a lifting mechanism for lowering the substrate from the supply conveyor onto the transport conveyor.

[0096] Item 6. An apparatus for transferring at least one material pattern from a respective surface of at least one web to at least one surface of a substrate, the apparatus comprising: a nip through which the substrate passes simultaneously with the at least one web, the nip having at least one pressure roller serving to press a surface of the at least one web and a surface of the substrate against each other as they pass through the nip; a web feed mechanism; and a substrate transport mechanism, the substrate transport mechanism further comprising a heater configured to heat at least one of the substrate and the at least one web prior to feeding the substrate and the web into the nip.

[0097] Clause 7: An apparatus for transferring a material pattern from a surface of each of two webs to an opposing surface of a substrate, the apparatus comprising: a nip through which the substrate passes simultaneously with the two webs, the nip having two pressure rollers that serve to press the surfaces of the two webs passing through the nip against the opposing surfaces of the substrate, a respective web feed mechanism associated with each web, and a substrate transport mechanism, at least one of the web feed mechanisms having at least one tension roller for aligning the two webs with respect to one another.

[0098] Item 8. An apparatus for transferring a material pattern from a surface of each of two webs to an opposing surface of a substrate, the apparatus comprising a respective web supply mechanism associated with each web, a substrate transport mechanism, and two nips through which the substrates pass in sequence, each nip having a pressure roller that serves to press the surface of each of the two webs and the surface of the substrate against each other as they pass through the nip.

Claims

1. 1. A system for transferring a material pattern to a substrate, comprising: a web carrying a material pattern; a web running mechanism for running the web through a nip between a roller and an opposite surface; and a transport conveyor for advancing the substrate toward the nip so that the substrate is gripped in the nip and frictionally runs through the nip simultaneously and at the same speed as the web, the web being pressed against a surface of the substrate as it passes through the nip, thereby transferring the material pattern from the web to the substrate, the transport conveyor being provided with at least one protrusion for engaging with a trailing edge of the substrate, the transport conveyor running to advance the substrate toward the nip at a speed slower than the passing speed of the substrate through the nip so as not to apply a compressive force to the substrate, and the trailing edge of the substrate automatically disengages from the protrusion when the leading edge of the substrate engages in the nip.

2. 2. The system of claim 1, wherein no further force is applied to the substrate from the transport conveyor in a direction that advances the substrate toward the nip, and the compression that is avoided is longitudinal compression of the substrate between the nip and the transport conveyor.

3. 2. The system according to claim 1, further comprising a supply conveyor which places substrates in an area to be pulled in by the protrusions of the transport conveyor so that the trailing edge of the substrate engages with the protrusions of the transport conveyor, thereby loading the substrate onto the transport conveyor.

4. 4. The system of claim 3, wherein the supply conveyor and the transfer conveyor overlap and straddle each other at an end of the transfer conveyor distal from the nip.

5. 5. A system according to claim 1, wherein each of the transport conveyor and the supply conveyor is formed by at least one endless belt which is cyclically movable.

6. 6. The system of claim 3, wherein the transport conveyor includes friction members that engage the substrate, thereby slowing the substrate down until it engages the protrusions.

7. A system as described in any one of claims 3 to 6, characterized in that at least one of the transport conveyor and the supply conveyor is formed by two parallel belts, the supply conveyor carries the substrate in a different plane than the transport conveyor, and the system is provided with a lifting mechanism for respectively raising or lowering the substrate from the supply conveyor to a range where it can be pulled in by the protrusions of the transport conveyor.

8. 8. The system of claim 7, wherein the plane of the supply conveyor is higher than the plane of the transfer conveyor, and each substrate is lowered by the lifting mechanism.

9. 9. The system of claim 7 or 8, wherein there is a low-friction static or rolling interface between the substrate and the lifting mechanism to ensure that pressure on the substrate is minimized when the substrate comes into contact with protrusions on the transport conveyor.

10. 10. The system of claim 1, wherein the transport conveyor protrusions are configured to make point contact with the trailing edge of the substrate.

11. 11. The system according to claim 1, wherein two or more pushers are arranged on one side of the transport conveyor at intervals in an X direction in which the substrate moves, and the pushers urge the substrate in a Y direction intersecting the X direction against an elongated guide surface arranged on the other side of the transport conveyor.

12. 12. The system of claim 11, wherein the pusher corresponds to a Y-direction registration of the substrate and the protrusion corresponds to an X-direction registration of the substrate relative to the nip, each relative to a material pattern carried by the nip and / or the web.

13. 13. The system of claim 1, wherein the opposite surface of the nip is stationary.

14. 13. The system of claim 1, wherein the roller is a first pressure roller and the opposing surface is formed by a second pressure roller, and two webs pass through the nip simultaneously with the substrate, the two webs consisting of a first web carrying a first material pattern and a second web carrying a second material pattern, and the first material pattern and the second material pattern are transferred to opposing surfaces of the substrate.

15. The system described in claim 14, further comprising at least one tension roller along the path of at least one of the two webs, the at least one tension roller configured to accommodate X-direction registration of at least one of the two webs with respect to the other.

16. 16. The system of claim 1, further comprising a heater for heating a substrate supported by the transport conveyor and / or one or more webs prior to reaching the nip.

17. 17. The system of claim 1, further comprising an applicator that applies adhesive to at least one of the substrate and the web before reaching the nip or passing through a heater, if present.

18. 18. The system of claim 1, further comprising at least one post-transfer station downstream of the nip, optionally selected from a cooling station configured to reduce a temperature of the substrate and / or one or more webs, a separation station configured to separate a web from a surface of the substrate, and a post-treatment station configured to alter the substance patterns and / or their adhesion to the substrate.

19. 20. The system of claim 18, wherein the material pattern includes particles of a conductive material, and the at least one post-transfer station is a post-processing station configured to sinter the particles to impart electrical conductivity to the material pattern.

20. A method for introducing a substrate into a nip formed between a pressure roller and an opposite surface and running the substrate therethrough, the method comprising: moving the substrate forward toward the nip by a transport conveyor having a protrusion formed thereon for engaging with a trailing edge of the substrate; the transport conveyor being set at a speed lower than the passing speed of the substrate through the nip; and configured such that when the leading edge of the substrate engages in the nip, the trailing edge disengages from the protrusion of the transport conveyor and stops applying force to the substrate.

21. 21. The method of claim 20, wherein the transport conveyor is configured to cease exerting a force on the substrate in a direction advancing the substrate toward the nip to avoid longitudinal compression of the substrate between the nip and the transport conveyor.

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