Transferring patterns to a substrate

Abstract

An apparatus and method for transferring a pattern supported on a web made of a deformable plastic material to a substrate is disclosed. The apparatus comprises a nip defined between at least one nip roller and a backing support, through which the substrate is transported simultaneously with the web, and the pattern is transferred from the web to the substrate by pressure applied by the nip. In the present invention, a web heater and a web tension adjuster are positioned upstream of the nip, and a control unit is provided to control the web heater and web tension adjuster. The control unit controls the web heater and web tension adjuster based on data indicating the length and width of the pattern on the web before transfer, or the length and width of the pattern on the substrate after transfer, thereby ensuring that the pattern conforms to a desired length and width after being transferred to the substrate.

Description

[Technical Field]

[0001] [Cross-reference to Related Applications] The present application claims priority under the Paris Convention based on British Patent Application No. GB2311276.6 filed on July 21, 2023, the entire disclosure of which is incorporated herein by reference as if fully set forth herein.

[0002] The present invention relates to transfer of a pattern from a web to a substrate, such as is performed in the manufacture of solar cells and circuit boards, wherein the pattern may be electrically conductive. [Background Art]

[0003] In the manufacture of certain products, a need arises to apply a material pattern to the surface of a substrate, and the applied pattern is intended to serve functional purposes, decorative purposes, or both. For example, in the manufacture of solar cells, circuit boards, touch screens, radio frequency identification (RFID) antennas, and the like, there is a composition containing particles of a conductive material, typically a binder that maintains the particles in a desired shape (e.g., a pattern of lines, a cross-section of a line, etc.), and / or an adhesive that can enhance adhesion to an intended substrate or promote functional interaction with the substrate. It may be desirable to apply a material containing the foregoing to a substrate according to a desired pattern. The substrate is, for example, a semiconductor wafer in the case of a solar cell, and an electrically insulating substrate in the case of a printed circuit board. Such substrates are typically rigid and planar, but flexible and / or non-planar (e.g., curved) substrates can also be used. In some cases, for example in the case of RFID devices or when the pattern is decorative, it may be desirable to apply the material pattern directly to a three-dimensional item having a flat or curved surface, such as a part of an apparatus body or a decorative article.

[0004] The applicant previously proposed in EP3826438 (which is incorporated herein by reference in its entirety) a method for applying a pattern of an electrical conductor to a substrate, comprising providing a flexible film or web having a layer made of a compatible plastic polymer such as a thermoplastic polymer that can be embossed or cast. The first surface of the film (or the front surface of the web) has a pattern. The pattern of grooves formed thereon corresponds to at least a portion of a desired pattern of an electrical conductor to be applied to the substrate. A composition comprising particles of conductive material and an adhesive is filled into the grooves on the first surface of the film or otherwise deposited thereon. The filling is performed in a filling cycle, and upon completion of filling, the composition substantially fills the grooves up to the same height as the first surface of the film, with the portion of the first surface between the grooves substantially devoid of the composition. Next, the film is brought into contact with the substrate such that the first surface of the film faces a desired face of the substrate, and pressure is applied to the film to adhere the composition filled into the grooves on the first surface of the film to the substrate. The film can then be separated from the substrate to transfer the composition from the grooves on the first surface of the film to the substrate. Subsequently, energy can be applied to sinter the conductive particles, making the pattern of the composition transferred from the grooves to the substrate conductive. A similar method is disclosed in the applicant's EP3491900, which is incorporated herein by reference in its entirety.

[0005] In EP3491902 (which is incorporated herein by reference in its entirety), the applicant further proposes an apparatus for transferring a pattern of a transferable composition, such as one comprising particles of conductive material and a heat-activated adhesive, from the surface of such a flexible web to the surface of a substrate. The apparatus comprises respective drive mechanisms for simultaneously advancing the web and the substrate through a nip, where the surfaces of the web and the substrate are pressed against each other. A heating station is provided to heat the web and / or the substrate to a temperature at which the adhesive in the composition is activated when the surfaces come into contact with each other, before and / or during passage through the nip. A cooling station can be used to cool the web after it has passed through the nip and before it optionally passes through a separation device that peels the web from the substrate, leaving the pattern of the composition attached to the surface of the substrate.

[0006] Using the methods and apparatus described above, for example, when applying a conductive pattern to a substrate, it has been found that the dimensions of the pattern may change after application to the substrate. The dimensions of the transferred pattern may differ not only from web to web carrying the pattern, but even patterns carried on the same web may gradually change in size during the transfer process from web to substrate. The changes can manifest in both the length of the pattern measured in the direction of web movement, the depth of the nip (also called the X direction), and the width measured laterally (also called the Y direction). Such variations can be caused by both the manufacturing conditions of the web carrying the pattern and the conditions during the process of transferring the pattern from the web to the substrate. Such variations can result in deviations from the desired nominal values ​​beyond acceptable differences. In such cases, the dimensionally mismatched transferred pattern may not be able to properly align with the substrate and / or the pattern transferred on the opposite side of the same substrate. Alternatively, even slight deviations from the desired dimensions may adversely affect the appearance and / or function of the transferred pattern.

[0007] The present invention aims to mitigate the problem of size variations between patterns applied to different substrates, a problem that is particularly pronounced when patterns are supported by a flexible web. [Overview of the project]

[0008] In one embodiment, the present invention provides an apparatus for transferring a pattern supported by a web of deformable plastic material to a substrate. The apparatus comprises at least one nip roller and a nip defined between the substrate and a support through which the substrate passes simultaneously with the web and to which pressure is applied in order to transfer the pattern from the web to the substrate, the apparatus further comprising a web heater and web tension adjuster positioned upstream of the nip, and a control unit that controls the web heater and web tension adjuster based on data indicating the length and width of the pattern on the web before transfer, or the length and width of the pattern on the substrate after transfer, thereby ensuring that the pattern matches the desired length and width after transfer to the substrate.

[0009] The pattern does not need to have the exact nominal dimensions of the desired size after being transferred to the substrate. The dimensions of the pattern may be within a tolerable deviation from there (in absolute terms, e.g., within 100 micrometers (μm), or in relative terms, e.g., within 1% of the ideal length and / or width). In some cases, the relative position of the pattern on the substrate is not important as long as the pattern conforms to the desired dimensions that characterize them, but in other cases, it may be more desirable for the pattern to be applied to a specific area of ​​the substrate. The desired area on the surface of the substrate is sometimes called the “transfer area,” while the area of ​​the substrate to which the pattern is not applied is sometimes called the “non-transfer area.” Generally, the non-transfer area forms a margin surrounding at least part of the pattern, but may instead (or additionally) be an area within the permitted transfer area. If the pattern on the web needs to be further aligned to at least one edge of the substrate, the dimensions of the substrate should be further considered or determined by the instrument so that each pattern can be aligned to each substrate to which it is transferred.

[0010] The relative alignment of each pattern with respect to the substrate can be addressed by at least one of the following: a) a web guide device designed to actively move the web along the Y direction upstream of the nip, intersecting its movement in the X direction toward the nip, or to maintain the web laterally within a predetermined path; b) an alignment device configured to position, among other things, the lateral edges of the substrate (i.e., its Y position) and / or rotate the substrate before it enters the nip, and / or to align it with the inclination of the pattern on the web; c) a speed change device configured to accelerate or decelerate the substrate so that the timing of its entry into the nip (i.e., its X position) coincides with the entry point of the web that holds the pattern to be transferred thereon.

[0011] For example, the apparatus can be configured so that the center of gravity of the pattern and the substrate substantially coincide (or are spaced apart) (e.g., through appropriate operation of a suitable web guide device, a substrate alignment device, and / or a substrate speed change device) so that both pass through the nip.

[0012] In some cases, when patterns are applied to both sides of a substrate and two patterns need to be aligned relative to each other, the desired length and width of the first pattern carried by the first web may be determined by the length and width of the second pattern carried by the second web. In such cases, heating and tension of at least one of the first and second webs can be set to ensure proper relative alignment. In some embodiments, when a particular transfer area is for an applied pattern, the patterns on separate webs (on the substrate side) need to be aligned not only with each other but also with the substrate. In such cases, at least one of the webs and the substrate may be aligned with each other (for example, as described above for a single web applying a pattern to one side of the substrate). When two webs are used to carry the same or different patterns separately to each side of the substrate, the transfer areas on both sides of the substrate are not the same (for example, their shape and position relative to the edge of the substrate).

[0013] In some embodiments of the present invention, the measurement of the pattern or fiducial (position reference mark) on the web is performed before the pattern reaches the nip where the pattern is transferred to the substrate, and during the process of transferring the pattern from the web to the substrate, and the temperature and tension of the web before entering the nip are adjusted according to the measurements.

[0014] In an alternative embodiment, the pattern transferred to the substrate is measured, and during the process of transferring the pattern from the web to a further substrate, the temperature and tension of the web before it enters the nip are adjusted according to the measurement.

[0015] The pattern length can be altered by changing the web tension upstream of the nip, but stretching the web in this way may also narrow the web width and thus the pattern width. Heating the web softens it, increasing its deformation as it passes through the nip, and both the pattern width and length increase with rising temperature. The present invention can ensure that the pattern is stretched as needed during transfer and conforms accurately and consistently to the desired length and width after being transferred to the substrate by correctly setting both the web tension and temperature before it reaches the nip, depending on measurements taken before the web enters the nip and / or after it exits the nip.

[0016] The length and width of the pattern can be measured during the manufacturing of the web, and encoded markings (such as barcodes) containing data indicating the size of the pattern may be applied to the web during manufacturing. In such embodiments of the present invention, the control unit of the apparatus is responsible for setting the temperature and tension of the web based on the data read from the web. The encoded markings can provide information related to the various variations that appear along the web at the unwinding distance, and the temperature and tension of the web are adjusted to be appropriate for the said distance.

[0017] Alternatively, or in addition to the above, there may be detectable data markings on the web. These data markings on the web may be a measure of the length and width of the pattern on the web in areas adjacent to the markings, enable actual in-line measurement of the dimensions, or indicate the optimal web temperature and web tension set by the control unit when transferring the pattern to the substrate. Such an approach is sufficient if maintaining constant temperature and pressure during pattern transfer consistently yields patterns transferred onto a substrate of a certain size. However, as mentioned above, in practice, it has been found that gradual size variations can occur while transferring patterns from a single web. To compensate for such errors, in an alternative embodiment of the present invention, the apparatus includes a sensor that acquires measurements indicating the width and length of the pattern on the web during transfer at an upstream position of the nip.

[0018] Because web temperature can only change relatively slowly compared to the rate at which the web is delivered to the nip (e.g., up to 1 m / s), this approach cannot be used to compensate for random variations in the size of patterns transferred from one pattern to the next on the same web. However, this approach does at least mitigate the stepwise size changes that have been experimentally observed.

[0019] In some embodiments, the sensor may include an optical sensor for determining the location of a particular marking on the web on the opposite side of the web, where the marking is either a fiducial or pattern element distinct from the pattern (e.g., conductive), and provides a measurement indicating the width of the pattern on the web. For example, the marking (or an element at a corresponding location in a subsequent pattern) is expected to be at a predetermined pitch between repeating occurrences along the web.

[0020] The nip may be associated with a shaft encoder that can measure the movement of the web through the nip. In such embodiments, the length of the web as it passes through the nip while an optical sensor detects a specific sequence of markings on the web serves as an indicator of the length of the pattern on the web.

[0021] In some embodiments, the web heater may be a heating roller positioned upstream of the nip, but it is also possible to heat a portion of the web by a blower or radiation, either instead or in addition to the heating. Furthermore, it is also possible to include a heater on at least one of the surfaces defining the nip where the transfer will be performed upon engagement (i.e., the nip roller or the backing support).

[0022] In some embodiments, the apparatus is adapted to transfer patterns to both sides of the same substrate. In such cases, the apparatus comprises two separate nips, each transferring a specific pattern from its respective web to a specific side. The nip can consist of a nip roller and a backing support, or two nip rollers aligned in a row with each other. Alternatively, two patterns can be transferred from their respective webs to each side of the substrate using the same nip, in which case the nip typically consists of two symmetrical nip rollers.

[0023] In some embodiments, the apparatus may include a web guide system upstream of the nip that can laterally change the position of the web relative to the side edge of the nip (i.e., the Y position of the web edge relative to the nip), and the web guide system includes any suitable web guide device that enables correct positioning of the side edge of the web relative to the nip (and thus positioning relative to a substrate independently aligned with the same nip) in response to a web edge sensor or other sensor capable of detecting the position of the web. The web guide system may include one or more web guide devices selected from a group including unwinding web guides, steering web guides, displacement web guides, and offset pivot guides, and the system further includes sensors, controllers, and / or actuators adapted to detect and correct (e.g., reduce or eliminate) deviations of the web from a desired position. For example, the actuators of the web guide system may be configured to displace and / or tilt rollers while the web is moving.

[0024] In some embodiments, the apparatus may include a substrate alignment device upstream of the nip, configured to correct at least the Y coordinate of the substrate relative to the nip (and therefore relative to the web and / or patterns on it that are independently aligned with respect to the same nip). In some embodiments, the alignment device can shift the substrate laterally by the same distance (right or left) as can be measured from the front to the rear edge of the substrate, and the X coordinates of the corners are not affected by the alignment. In other embodiments, the alignment device can further modify the X coordinates of at least three of the corners of the substrate. In other words, the alignment device can rotate the substrate relative to the direction in which it was initially supplied when it was loaded into the substrate drive mechanism. These lateral movements or rotations of the substrate can be achieved, among other things, by a substrate alignment device having lateral contacts located on the opposite side of the substrate and movable in the Y direction relative to each other, the lateral contacts being reversibly biased toward each other, grasping the opposite side edge of the substrate at any desired position relative to the nip, and advancing the substrate toward the nip at a desired alignment controllable by the contacts.

[0025] In some embodiments, the apparatus includes a speed changer upstream of the nip, configured to accelerate or decelerate the substrate before it enters the nip, and the timing of entry into the nip (i.e., their X position) is determined by the pattern to be transferred to the web.

[0026] The patterns that can be transferred onto a substrate by using the apparatus and / or method described herein can be functional or decorative, and the substrate and transferable composition carried by the flexible web are selected and adapted according to the desired end use of the transferred pattern.

[0027] In particular, since the pattern is carried by a flexible web, the substrate to which the pattern is transferred does not need to be rigid and flat, and flexible substrates and / or non-flat (e.g., curved) substrates can also be used and can benefit from the teachings of the present invention.

[0028] In another aspect, there is provided a method for ensuring that a pattern carried by a web of deformable plastic material conforms to a desired length and width after being transferred to a substrate at a transfer nip, the method comprising the steps of: a) collecting data indicative of the length and width of the pattern on the web before transfer or the length and width of the pattern on the substrate after transfer; and b) controlling the temperature of the web and the tension of the web upstream of or at the nip in dependence on the collected data.

[0029] These and additional advantages and features of the present invention will be better understood when the following detailed description is read with reference to the drawings and non-limiting examples.

[0030] Hereinafter, the present invention will be further described by way of example with reference to the accompanying drawings. In the drawings, like reference numerals or characters indicate corresponding or like components. The description, together with the drawings, will make it clear to those skilled in the art how some embodiments of the present disclosure may be implemented. The drawings are for illustrative purposes, and no attempt is made to show structural details of the embodiments beyond what is necessary for a basic understanding of the present disclosure. For clarity and ease of presentation, some objects depicted in the figures are not necessarily drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] [Figure 1] Figure 1 is similar to Figure 1 of EP3491902, reproduced herein for completeness to show an exemplary apparatus for transferring a pattern from a web to a substrate. [Figure 2] Figure 2 is a schematic diagram showing details of the web feeding apparatus of Figure 1 modified to carry out the present invention. [Figure 3] Figure 3 is a perspective view showing a part of the web feeding apparatus of Figure 2. [Figure 4] Figure 4 is a perspective view of a portion of a web, schematically showing a pattern within and / or on the web. [Figure 5]Figure 5 is a perspective view of a portion of the web, schematically illustrating a single pattern and the measurement method for it. [Figure 6] Figures 6A-6C are schematic side views of the nip through which the web and substrate pass and transfer. [Figure 7] Figure 7 is a flowchart of the steps that may be included in carrying out the method according to the present invention. [Modes for carrying out the invention]

[0032] [Device Overview] The exemplary apparatus in Figure 1 is intended to apply a pattern to the opposite side of a substrate 10 drawn from a substrate supply device such as a stack 12, and the pattern consists of a transferable composition which may contain conductive material particles and an adhesive that can later be activated by heat and / or pressure. In such cases, energy can be applied to sinter the composition and make the pattern conductive. Thus, in one example, the substrate 10 may be a semiconductor wafer or an insulating substrate to which the apparatus applies front and back patterns (e.g., electrodes, circuits, antennas, etc.) of a desired final product. However, the composition may not require the application of energy to become conductive, and conductivity may not be necessary if the pattern has other functions or is purely decorative. If the pattern needs to be processed to produce desired functional and / or aesthetic effects, for example, if it needs to be heated to become conductive or melted or cured to improve adhesion to the substrate, this processing is usually performed after the pattern has been transferred to the appropriate substrate and can be done offline from the roll-to-roll apparatus illustrated in this figure.

[0033] Two patterns that can be applied to each side of a substrate are usually not the same, but may need to be correctly aligned with each other and with respect to the substrate. In the substrate drive mechanism 90, substrates 10 are fed one by one from the stack 12 to the inspection station 60, where defects on the top surface of the substrate are optically analyzed by appropriate inspection equipment located at the inspection station 60. At the subsequent selection station 62, substrates found to be defective can be ejected by appropriate selection equipment. Defect-free substrates 10 are sent to the alignment device 50, which in one embodiment may also be heated by a heater 52. After being heated as necessary and correctly positioned and oriented at the alignment station, the substrate 10 is fed into a nip 40 defined between two pressure rollers 22a and 22b in this figure. Reference numbers assigned to stations (subsystems) within the device can also be used to identify the associated devices that perform the functions assigned to the stations. For example, reference number 60 can be interchangeably used to refer to a station that can inspect a substrate, or to an inspection device selected to detect defects associated with the substrate.

[0034] It is recommended to include inspection station 60 and selection station 62 for detecting and removing defective substrates, although such stations are not essential for the operation of the apparatus and are only desirable from a quality control perspective. Further stations performing a similar role downstream of the nip, typically following the delamination of the flexible web, may also be optionally included to detect defective patterns and remove such defective substrates. In Figure 1, downstream inspection of the substrate and / or the pattern transferred to the substrate is schematically illustrated by sensors 80a and 80b. These sensors may be the same as or different from the sensors located upstream of the nip (optical sensors such as sensor 70, and cameras 122 and 601, for example), all of which are described in detail below.

[0035] If the apparatus includes stations 60 and 62 upstream of the nip, it may be desirable to further include an acceleration station 64 that pulls in defective substrates after they have been ejected and allows them to reach the nip in synchronization with the web pattern. Thus, such an acceleration station 64 can prevent "empty" web feeding at the nip when there are no substrates. However, such an acceleration station is not essential, and such empty feeding can be tolerated or mitigated by alternative means, or similar solutions, such as adding defect-free and pre-selected substrates from a buffer of defect-free substrates (e.g., wafers).

[0036] Station 64 can be used more generally to change the speed of the substrates being fed to the nip 40, regardless of the presence of an inspection station 60 or a selection station 62 configured to detect and remove defective substrates 10. Thus, station 64 is also called a speed change station, and the synonymous devices contained therein can accelerate or decelerate the substrate as needed, thereby ensuring that the substrate is synchronized with the pattern on the web to which it is aligned as it enters the nip. In this figure, the pattern of the composition to be transferred to the substrate is held by two flexible webs 14a and 14b. The material to be transferred (also called the transferable composition) can be placed in recesses (such as grooves) beneath the surface of the web and / or on the surface of the web. The side of the web that carries the pattern of the material is called the front of the web, and the opposite side of the web is called the back.

[0037] As is evident from Figure 1, the drive mechanisms for the two webs 14a and 14b can be mirror images of each other. To avoid repetition, this specification uses reference numbers without suffixes to refer collectively to the components of both web drive mechanisms, although the drawings use the suffixes "a" and "b" to distinguish the upper and lower drive mechanisms.

[0038] Each web 14 is pulled out from the motorized feed roll 16 via an idler roller 18 and a dancer 20, the dancer 20 moving from left to right as indicated by arrow 21 to pull out or release slack in the web. The rewinding device 16 also functions as a web guide, and the feed roll is movable in a direction parallel to its longitudinal axis of rotation to adjust the lateral position of the web. In the diagram of this device, lateral guiding of the web is achieved by moving the feed roll forward or backward in the plane of the drawing. Guiding of the lateral edge of the web can be achieved additionally or alternatively by appropriate steering rollers appropriately positioned along the path of the web.

[0039] For example, roller 18 near the nip may, if necessary, act as a steering guide to "bend" the web, ensuring that the web arrives at a future station (e.g., nip 40) in a better aligned position with the desired location. If required to meet additional placement constraints, other displacement guides can be used to provide lateral guidance for the web. All of the aforementioned web guides are referred to as web guide systems, and each guide system may include its own sensing system and controller, and actuators capable of performing necessary corrective actions (such components are not shown in the diagram if they are separate).

[0040] Next, the web 14 passes between two pressure rollers 22 that define the nip 40 into which the substrate is fed. Within the nip, the composition pattern on the web 14 is pressed against the surface of the substrate 10, resulting in the composition pattern adhering to the substrate. The web then passes through a cooling station 23, as shown in this figure, and is sent to a separation device 30 through two rollers 26. After being separated from the substrate 10 by the device 30, the web is rewound onto a winding roll 32. Flexible webs are discarded after one use, considering the cost of the plastic material that constitutes them and the methods that can be used to manufacture them (such as roll-to-roll embossing). Flexible webs, once separated, may deform irreversibly in some cases, and such deformation does not affect the pattern transferred from the separated web.

[0041] To ensure accurate alignment of the configuration pattern with the substrate, an optical sensor 70 is positioned upstream of the idler roller 18 to sense the pattern or associated markings on the web 14. Any type of optical sensor may be suitable for this device, provided it is compatible with the pattern and / or markings to be detected. Optical sensors include image sensors, fiber optic sensors, contrast sensors, or other similar sensors adapted to detect optical signals.

[0042] Figure 4 schematically shows a perspective view of a web that can be used in the apparatus and method taught in the present invention. In Figure 4, arrows 400 represent any sensor suitable for measuring the width W and length L of a pattern 410 containing a transferable composition inside or on the surface of a flexible web 100. Markings 420 and 430 detectable by the sensor 400 are provided on the web, and although the markings are on both sides of the web in this figure, they are not limited to this, and the markings may also be provided upstream and / or downstream of each pattern, and may even be placed within the pattern. This figure also shows how a particular element 440 in the pattern may alternatively or additionally perform similar detection and measurement functions. Downstream of the nip after web peeling, if there are markings relevant to detection and measurement by downstream sensors, these are usually specific elements in the transferred pattern, unless the fiducial markings are made of a transferable material. In this figure, a single sensor 400 is shown. This is suitable when the sensor's detection field is wide enough to recognize all markings relevant to the intended measurement (for example, when positioned on opposite sides of the web as shown by markings 420 and 430), and the sensor is positioned to detect both ends of the web, ideally. If the sensor's detection range is even more limited, multiple sensors may be needed to detect all relevant markings. In this figure, the thin horizontal lines of the pattern may represent traces called "fingers" when transferred to the solar cell substrate, while the wider horizontal lines may represent busbars. The transferable compositions for forming the fingers are typically located in recesses beneath the surface of the web, and these grooves have a cross-sectional profile that fits the solar cell fingers (for example, the groove cross-section is triangular and preferably has a high aspect ratio). In contrast, the transferable compositions for forming the busbars are found on the surface of the web.

[0043] For brevity, this specification has described the transfer of a pattern from web to substrate, which involves controlling a web heater and web tension adjuster (located upstream of the transfer nip) based solely on data indicating the characteristic dimensions (e.g., length and / or width) of the pattern measured on the web before transfer or on the substrate after transfer (or both). However, the length and width of the pattern are not the only dimensions required to achieve the desired values.

[0044] Figure 5 shows a single pattern used to illustrate how measurements are derived from relevant data acquired by an appropriate sensor, camera, or scanner. While the outline of the pattern schematically shown in Figure 4 is a top-down view of a square, the outline of the pattern in this figure (shown as a dotted line) is closer to a trapezoid for clarity in the following explanation. For simplicity, we refer to a pattern on a web, but similar considerations apply to a pattern transferred to a suitable substrate. Thus, on a web, the lateral edges help in positioning points measured within the plane of the web (e.g., the pattern, its contour, and / or its associated markings) (e.g., setting axes for determining the (x,y) coordinates), and similarly, the lateral edges of a substrate can help in positioning points measured on the surface of the substrate.

[0045] By taking one of the web's lateral edges as a reference line (for example, the lower horizontal boundary of the web in this drawing) and setting a specific point on it as the origin of this axis (i.e., with coordinate (0,0)), the position of any point on the web can be determined by evaluating the (x,y) coordinates of each point in the XY plane in which the pattern exists. The width W and / or length L of the pattern, and the deviation from the desired value, or variation between consecutive measurements of similar dimensions, can be determined by repeatedly measuring the distance between two points indicating the width or length of the pattern at similar positions on each pattern. The pattern shown in Figure 5 has four points A-D marked up. These points are shown at the four corners of the pattern's contour, but this should not be interpreted as limiting; points can also be selected from fiducials on the web or elements within the pattern. Although not shown in this figure, subsequent patterns have four feature points A'-D' at corresponding positions, and subsequent patterns are characterized by points A''-D'', then A'''-D''', and so on. The width of a pattern can be evaluated by measuring the distance between points A and C or between points B and D and comparing the calculated value to relevant reference data or similar calculations. Gradual changes in width between points A'-C' or B'-D', A''-C'' or B''-D'', A'''-C'' or B'''-D'', etc., can be monitored to take corrective actions or evaluate their effectiveness. Similarly, the length of a pattern can be evaluated by measuring the distance between points A and B or between points C and D and comparing the calculated value to relevant reference data or to similar calculations performed between points A'-B' or C'-D', A''-B'' or C''-D'', etc.

[0046] Alternatively, the width and / or length of a pattern can be calculated as the average of two or more measurements. In this figure, only four points are drawn to characterize the pattern, so the average of two distances is considered. The width W of the pattern can be calculated by averaging the distance between points A and C (W1) and the distance between points B and D (W2). The length L of the pattern can be calculated by taking the average of the distance between points A and B (L1) and the distance between points C and D (L2).

[0047] Once the positions of these four exemplary points are determined following appropriate data acquisition, more information can be calculated. For example, the position of the pattern's center of mass can be determined by averaging the positions of points A through D in each (x,y) coordinate system. This point E is represented by a star in this diagram.

[0048] Similarly, determining the coordinates of points characterizing the pattern on the web allows for a further evaluation of the pattern's relative position to the web's edges. In some cases, it may not be sufficient for the pattern to simply fit the desired length and width; it may also be required that the pattern lies within a specific area of ​​the web (i.e., outside a specific margin). Taking the pattern width as an example, it may not be sufficient for the distance between points A and C or between points BD, or the average of W1 and W2, to meet a baseline value set as W; it may also be necessary that the distance between point AD and the nearest projection on each web edge be greater than a value set as a margin where the pattern may not exist on the web (or on the substrate after transfer). Likewise, it may not be sufficient for the distance between points A and B or between points CD, or the average of points L1 and L2, to meet a baseline value set as L; it may also be necessary that the distance between each of points A-D and the nearest projection on the substrate edge be greater than a value set as a margin where the pattern may not exist on the substrate. The relative displacement between the centroid E of the pattern derived from measurement points A-D and the ideal position of the centroid of the reference pattern may also indicate distortion of the pattern's shape. Alternatively, the tilt of the pattern direction can be evaluated by measuring the angle between the edge of the web and a straight line passing between two points selected for this purpose. In the description based on the pattern shown in Figure 5, line AB is expected to be parallel to the lateral edge of the web, and the angle formed between this imaginary line and the edge (e.g., the line at the top of the figure) represents the tilt angle a alpha. To some extent, the tilt of the pattern can be corrected by giving the substrate a similar tilt using a alignment device 50 which may include a lateral pusher (e.g., changing the Y coordinate of at least one corner) that can assign a gentler angle to the substrate as the substrate enters the nip. In practice, the tilt of the pattern (usually resulting from manufacturing inaccuracies) can only be corrected by forming an angle with the intended direction that does not exceed the ability of the substrate alignment device to slightly rotate the substrate to improve the alignment between the edge of the substrate and the intended direction of the pattern.In other words, assuming all other parameters are as desired, if the web edge should be parallel to the side edge of the substrate, then the fact that the virtual line AB is not parallel to the web side edge can be ignored, and the substrate is rotated so that its side edge is parallel to line AB.

[0049] Up to this point, dimensions have been discussed in relation to deformable web patterns, but a similar approach can be applied to substrates. However, in the case of rigid substrates, the width and length values ​​can be predetermined by the manufacturer or determined before loading into the equipment. That being said, they can also be evaluated independently in line by equipment with appropriately placed sensors along the substrate drive mechanism. The front and rear ends are used to determine the length of the substrate, and the side ends may be used to determine the width of the substrate. The points that characterize the substrate are its four corners, or, if there are no intersecting straight edges, virtual points set at the intersections of the straight portions of the substrate edges (these four points are, for example, called Alef, Bet, Guimel, and Dalet). The position of the centroid (He) of the substrate can be calculated in the same way as for patterns. For the pattern and the substrate to be properly aligned, it may be necessary that their respective centroids (E and He) coincide, or that one is positioned relative to the other according to a reference vector. After transfer, eight points—points A-D characterizing the pattern and Alef-Dalet characterizing the substrate—can be considered, allowing for direct evaluation of the contour of the transferred pattern and the actual margin between it and the substrate. The figure schematically shows an apparatus capable of simultaneously transferring two patterns to opposite surfaces of a substrate, but those skilled in the art will readily understand how to prepare a similar apparatus to transfer a pattern of a composition to a single substrate side. In such a case, the nip 40 can be formed, for example, between a single pressure roller 22 and a support 42 of the substrate 10. Furthermore, the transfer of two patterns to opposite surfaces of the substrate does not need to be performed simultaneously; in that case, the apparatus can include two separate nips, one for each web and each face of the substrate.

[0050] These alternatives are schematically shown in Figure 6, where panel A shows a single nip 40A formed between one pressure roller 22 and a backing support 42, panel B shows a single nip 40B formed between two pressure rollers 22a and 22b, shown in similar dimensions in this figure, and panel C shows two consecutive nips 40' and 40'', respectively, as previously shown in nip 40A. Separate first and second nips, used for transferring the substrate to different surfaces, can be selected independently from nip types 40A and 40B, although not shown in other cases. In Figures 6A–6C, the surfaces constituting the illustrated nips are shown engaged with each other, and the substrate and web are omitted for clarity. As will be readily apparent to those skilled in the art, the surfaces forming the nip can also be released as needed, for example, for maintenance, repair, or cleaning of the equipment.

[0051] The apparatus includes additional stations not shown in the diagram (some of which are optional offline stations) that perform activities that are carried out at different times and / or locations and / or handled by different entities. For example, the apparatus may include a curing station for curing the transferred pattern, a furnace for sintering the particles of the transferred composition and / or fusing the transferred pattern to its respective substrate, an overcoat station for overcoating the transferred pattern, and similar post-transfer processing stations that can bring the transferred pattern and its respective substrate closer to the intended ready-to-use final product. Each of these stations, whether offline or inline, can be called a finishing station. The apparatus may also include other inline stations to facilitate any of the operations already described and further detailed below. Some of these stations and associated devices operate on the substrate and / or web before entering the nip and are generally called pre-transfer stations (omitted from the diagram for clarity). For example, the apparatus may include a pre-coating station that can selectively or continuously apply an adhesive layer onto the pattern upstream of the nip, on the web, on a selected area of ​​the substrate, or both, while forming an intermediate adhesive layer. A nip is provided between the pattern and the substrate to facilitate the transfer of the pattern from the pattern to the substrate at the nip portion.

[0052] Having outlined an exemplary apparatus capable of carrying out the present invention, the individual components and parts of the apparatus will now be described.

[0053] [Board drive mechanism] The apparatus shown in the drawings is intended for use in the manufacture of solar cells or printed circuit boards, where the substrate is typically rigid and has the shape of a square semiconductor wafer or a rectangular insulating substrate. Before describing the drive mechanism in detail, it should be made clear that its design actually depends on the properties of the substrate, which may depend on the type of pattern (functional or decorative, etc.) transferred to the substrate. In another embodiment, if the substrate itself is flexible, the substrate drive mechanism may be similar to that of a web drive mechanism. If the substrate is a 3D article with a pattern (e.g., conductive) on only one side, the substrate drive mechanism 90 may be a conveyor passing under a single pressure roller 22. Such adaptations and modifications are readily implementable by those skilled in the art and therefore do not need to be described in further detail herein.

[0054] In the embodiment shown in Figure 1, the substrate drive mechanism 90 includes a cassette in which a stack 12 of individual substrates 10 is stored. A conveyor belt (not shown) transports the substrates 10 one by one from the stack 12 to an inspection station 60 (e.g., for optical detection of defects), where they are observed from above by a camera 601. Images from the camera can be analyzed by a computer programmed to detect defects such as cracks and scratches. A selection station 62 following the inspection station 60 may include, for example, a solenoid-operated deflector under the control of the image analysis computer of the preceding station, which discharges defective substrates from the conveyor into a waste container. Only defect-free substrates are passed to the next station, where they are heated as needed and correctly aligned with respect to the nip and the pattern to be transferred thereto. Correct positioning of the substrate with respect to the nip can be achieved by using appropriate abutments. Correct alignment with respect to the incoming pattern carried by the web can be achieved by accelerating or decelerating the feeding of the substrate to the nip depending on the distance from the pattern to the nip and the speed of the web. In some embodiments, the substrate drive mechanism 90 is configured and adapted to supply the substrate to the nip 40 at a linear velocity of at least 0.1 meters per second (m / s), at least 0.5 m / s, or at least 0.7 m / s. Typically, the linear velocity of the substrate at the nip does not exceed 2.0 m / s and is generally in the range of 0.2 m / s to 1.5 m / s, 0.4 m / s to 1.0 m / s, or 0.5 m / s to 0.8 m / s.

[0055] [Heating and alignment station] As the name suggests, this station performs two different functions. First, it plays the role of heating the substrate 10 to a temperature that activates the adhesive in the composition carried by the web 14 when the two come into contact at the nip. The appropriate temperature varies depending on the composition and the properties of the adhesive, which are described in more detail in EP3491900.

[0056] The heating station (represented by the dotted box 52) can take various forms depending on the temperature to be reached, and can be achieved by conduction (the substrate is in contact with a hot plate and heated by a circulating fluid, resistance heating element, or PTC resistor), convection (heated gas is blown onto the substrate), or radiation (infrared or microwave depending on the properties of the substrate). When conducting, it may be desirable to further include an element that can keep the substrate in close contact with the hot plate (e.g., a roller that forms a nip with the plate) to accelerate the heating of the substrate to the desired temperature.

[0057] Heating can be performed upstream of the nip, and at least one of the web surface and the substrate surface can be heated separately to force one to come into contact with the other, but instead, and / or additionally, heating can also be performed at the nip. For example, in such an embodiment, the pressure roller 22 can also function as a heating roller.

[0058] The web 14 is made of a flexible material from which grooves can be formed by various possible processes (e.g., embossing or casting). The shape of the grooves is complementary to the shape of a desired pattern, such as a conductor, and can be filled with a composition comprising particles of a conductive material, such as silver, and an adhesive that can be activated by heat and / or pressure. As previously mentioned, for certain types of relatively flat conductive patterns, such as the back electrodes of solar cells or the ground plane of a PCB, the composition can instead be placed on the surface of the web. In this context, it is sufficient to know that the web carries a pattern of a composition that matches at least a portion of a desired pattern (e.g., a conductor) applied to the substrate, but interested readers can find more details about the types of materials from which the web is used in EP3491900, including methods for fabricating the web, methods for fabricating the grooves, and the chemical structure of the components of the composition. The composition itself does not need to be conductive, but it should be noted that it may become conductive when sintered if a conductive pattern is required. Furthermore, although this specification primarily refers to the transfer of patterns intended to be conductive, the present invention should not be construed as being limited to such patterns. The present invention may be useful for transferring all kinds of patterns (e.g., those with functions other than conductivity or decorative ones) where it is important to maintain the size of the transferred pattern within strict dimensions or within an acceptable deviation therefrom.

[0059] For the purposes of the present invention, it should be noted that the web has sufficient inelasticity to maintain the contours of the grooves (and patterns) and the shape of the composition transferred therefrom. On the other hand, the web has sufficient elasticity (e.g., stretchability) to facilitate the alignment of the pattern supported on the substrate by the dancer and tension. Therefore, plastic materials that can produce a deformable web (or its layer, typically the layer in contact with the substrate) include any polymer whose shape can be altered as a result of the operating conditions of the apparatus used to manufacture the web (e.g., the apparatus for embossing the web) or the apparatus used to transfer the web. Furthermore, since the deformable plastic web can be irreversibly deformed when separated from the substrate, it is suitable for single use and can be discarded after use. Suitable materials for such a web (or outermost deformable layer) include thermoplastic polymers including cyclic olefin copolymers (COCs), polypropylene (PP), polyethylene (PE), thermoplastic polyurethane (TPU), and copolymers thereof.

[0060] The dancers can also function as buffers until the web reaches a constant velocity. Because the diameters of the various motorized cylinders that contact the web along its path differ, some inertia may occur between the cylinders until they can all provide the same linear velocity. The web preferably has enough flexibility to conform to the substrate surface and allow for sufficiently close contact for the transfer of the constituent lines. This ability is related to the presence of at least a thermoplastic polymer in the layer forming the first surface / front of the web. When heated as described above, the thermoplastic layer on the first surface of the web is expected to soften sufficiently to substantially conform to the terrain of the substrate surface. For example, assuming the substrate has a random or patterned textured surface with pyramidal protrusions, such as those found on silicon substrates for solar cells, the web's conformability, particularly when heated, allows the thermoplastic surface to fill almost the entire surface of the substrate. The spacing between adjacent relatively protruding textures is relatively shallow. It should be noted that thermosetting polymers used in the manufacture of dimensionally elastic molds (such as those used in intaglio plates) cannot achieve such topographic conformability under normal operating conditions.

[0061] Other desirable properties can be easily understood, and the web can be adapted to processes performed by the apparatus (e.g., stress resistance, heat resistance, thermal conductivity or heat dissipation), as well as to compositions used therein (e.g., chemical resistance, chemical inertness), and at the same time, the length and width of the pattern can be adjusted in response to changes in temperature and tension according to this teaching.

[0062] [Pressure roller] The purpose of the pressure roller 22 is to press the web 14 against the substrate 10. A force is applied to the pressure roller 22, applying a compressive force to the nip 40. The magnitude of the force depends on the properties of the web, the composition held within and / or on the web, the substrate, and the shape of the pattern (e.g., groove depth and / or cross-sectional profile, pattern complexity, etc.). The speed at which the web is fed to the nip (i.e., the time the web is subjected to pressure) and the desired transfer quality can also influence the magnitude of the applied force. The pressure roller can be made of a suitable material such as rubber or steel, but is coated with a thin layer of flexible material to ensure good contact across the entire surface area of ​​the web. Thus, while the nip can ideally be considered a contact line formed between the web and the substrate surface, in practice, if compressible material is present on the sides of the nip that contact the back of the web, the nip will form an elongated contact area parallel to the width of the web.

[0063] As mentioned above, in some embodiments, if heating is not performed only on the substrate and also not on the web upstream of the nip, the pressure roller 22 can also function as a heating cylinder. Furthermore, the pressure roller can be motorized to pull the web from the feed roll 16. As shown in the figure, if a nip is formed between two pressure rollers, it is sufficient to motorize only one of the pressure rollers as needed.

[0064] It is important to ensure that the pattern on web 14 is synchronized with the arrival of the substrate when it reaches nip 40, regardless of whether it is below or above the surface of the web. The pattern of the configuration is spaced apart on the web, and the gaps allow the web to pass through nip 40 while it is oriented so that a new substrate is correctly fed into the nip, and this alignment is optionally performed while the substrate is heating. Since the web is driven continuously, but the presentation of the substrate to nip 40 is intermittent, a problem arises where the time the pattern arrives at the nip may not coincide with the presence of the substrate in the nip.

[0065] To avoid this problem, the web is pulled from the supply roll 16 by the rotation of the supply roll 16 or the take-up roll 32. A sensor 70 is provided to detect when the pattern has arrived at a specific position as the web leaves the supply roll 16. If the expected arrival time of the pattern at the nip 40 does not match the next arrival time of the substrate 10 at the nip 40, the movement of the dancer 20 may change the length of the web path from the supply roll 16 to the nip 40, resulting in an increase or decrease in the time it takes for the sensed pattern to reach the nip 40. Therefore, by controlling the dancer 20 according to the time when the pattern is detected by the sensor 70 and the time when the substrate 10 is sent to the nip 40, accurate alignment between the pattern and the substrate can be ensured. If patterns on opposite sides of the substrate are both correctly aligned with respect to the substrate, those patterns will also be correctly aligned with respect to each other.

[0066] Any suitable alignment device 50 can be used in connection with the present invention, but the applicant has devised various methods for timely supplying the substrate to the nip while ensuring proper alignment with each pattern. In addition to the apparatus disclosed in EP3491902, interested readers may refer to EP4049308 and EP4320059 for alternative methods and apparatus for carrying them out, all of which can function as alignment devices 50. In some cases, if distortion of the pattern orientation on the web is observed before or after pattern transfer, it may be advantageous to use an alignment device that can tilt the substrate to match the distortion of the pattern orientation on the web.

[0067] [Cooling Station] In the illustrated embodiment, cooling of the web 14 after passing through the nip 40 is performed by conduction. The endless cooling belt 24 passes over the first roller 26 and the second roller 26, and tension is maintained by the idler roller 28. In this way, the cooling belt 24 is maintained in thermal contact with the back side of the web over its entire length from the pressure roller 22 to the second roller 26.

[0068] The cooling belt 24 may not require additional cooling because it is exposed to ambient air for the remainder of its length. If the belt 24 needs to be cooled, a blower can be used. It is configured to blow air onto it, and the air is preferably cooled, but not necessarily required.

[0069] Alternatively, the cooling belt 24 can be omitted, and air can be blown directly onto the back of the web to cool the web downstream of the nip. If necessary, the air can be cooled to a temperature not exceeding 20°C using a cooling circuit or the like. Alternatively, a heatsink suitable for lowering the temperature to the desired temperature range can be used instead of the cooling belt.

[0070] While passing through the cooling station 23, the web 14 remains attached to the substrate 10. As the web cools, the adhesion of the composition to the web decreases and / or conversely, the adhesion of the composition to the substrate increases. Such changes in relative adhesion to the source and target surfaces facilitate subsequent separation of the web from the substrate, if necessary. Thus, the temperatures reached or maintained by the cooling station may depend on the web, the substrate, and any future operations they may undergo together. If the cooling station is a heat sink, it is advantageous that the temperatures of the web and substrate as they exit the cooling station can be controlled to suit the functions performed at downstream stations.

[0071] Active cooling of the web 14 and / or the substrate 10 beneath it is intended to facilitate the proper separation of the web from the substrate so that the pattern of the transferable composition remains properly adhered to the substrate; therefore, cooling may not be necessary if separation of the web is not required, or at least not imminent.

[0072] [Separation device] The separation device 30 shown in an exemplary embodiment of the illustrated apparatus comprises a metal plate bent or manufactured to define an acute angle, such as that found in a blade. The web on its return path to the winding roller 32 is bent over the sharp edge defined by the outer side of the separation device. This action peels the web 14 from the substrate 10, leaving the composition attached to the substrate 10. Those skilled in the art will readily understand that if such separation is desired, similar web peeling can be satisfactorily achieved by alternative separation devices, such as one in which the web rotates toward the winding roller. A rod or rotating cylinder is merely one example of such an alternative device.

[0073] In some embodiments, it may be desirable to leave the web 14 attached to the substrate 10 as temporary protection for the pattern or as permanent cover for the pattern until it is separated later (optionally by a different facility and / or a different entity). In such cases, the web 14 does not need to be unwound by the winding roll 32 and can be removed from the supply roll 16 by any device suitable for this purpose. Furthermore, if the separation of the web and substrate is delayed or omitted, it may not be necessary to cool the web 14 downstream of the nip 40 or to a temperature selected to facilitate separation. Furthermore, in such cases, particularly when the substrates are supplied to the nip as individual units, the device may include a cutting device for slitting the web remaining on the substrates in the unbonded margin between any number of adjacent substrates. The cutting device (not shown) can separate each single substrate from the next substrate or separate a set of two or more substrates from the next set of substrates.

[0074] One embodiment of the present invention is partially shown in Figures 2 and 3. For clarity, many components already described with reference to Figure 1, such as the substrate feeding device (e.g., 12), the substrate driving mechanism (e.g., 90, conveyor not shown), the alignment station (e.g., 50), and optional substrate inspection stations (e.g., 60), selection stations (e.g., 62), speed change stations (e.g., 64), and heating stations (e.g., 52) located upstream of the nip, have been omitted, as have other pre-transfer stations required for the particular apparatus (or method). Similarly, post-transfer stations located downstream of the nip (40), or downstream of the separation station (e.g., 30), if one is present, have also been omitted. Figures 2 and 3 schematically show only a portion of the apparatus shown in Figure 1 as modified to carry out the present invention. The web 100 in Figures 2 and 3 is pulled out from an electric feed roll (not shown, but corresponding to roll 16 in Figure 1, which is also a web guide unwinder as previously described) in the direction indicated by arrow 130 within the nip area, first passing over a dancer 102 positioned between two guide rollers 104 and 106. Next, the web 100 passes through a tension nip formed between an electric tension roller 110 and a rubber roller 112, and then over a guide roller 108. The rubber roller 112 is pressed against the web with constant pressure to prevent slippage between the tension roller 110 and the web 100. The web is simultaneously and / or after being heated by a web heater (e.g., by passing around a heating roller 114), and then reaches the nip roller 116, where the pattern is transferred from the web 100 to the substrate. If a nip roller 116 (corresponding to the pressure roller 22 in Figure 1), or if a nip is formed between two nip rollers as shown in the figure (for example, a nip 40), at least one of them (for example, the upper roller) can be motorized to drive the web 100.

[0075] Dancer 102 is equivalent to dancer 20 in Figure 1, and its role is to act as a buffer during the initial acceleration and / or final deceleration of the system when the linear velocities of the different rollers have not yet matched. The dancer is used to ensure accurate alignment of the pattern with the substrate by accelerating or decelerating the substrate feed, which is also associated with camera 118. The position of the substrate relative to the nip can be confirmed upstream of the nip by a sensor (e.g., an optical sensor) that can monitor the edge of the substrate, the fiducial on the substrate, or both. Such a sensor may be part of a substrate alignment device (shown as station 50 in Figure 1).

[0076] A control system 120 is provided to correct dimensional errors in the pattern transferred to the substrate. As shown by the dotted line in Figure 2, the control system is electrically connected to receive data signals from a camera 122 and a shaft encoder associated with the nip roller 116, and transmits control signals to set the speed and / or torque of the motorized tensioning roller 110, the temperature of the heating roller 114, or alternatively and additionally, the temperature of any other heating devices positioned upstream of the nip or along the path that the web follows within the nip. For example, a segment of the web 100 between the guide roller 106 and the nip roller 116, or between the tension roller 112 and the heating roller 114, can be heated by convection or radiation (e.g., using an infrared heater).

[0077] As shown in Figure 2 and best illustrated in Figure 3, two cameras 122 can be positioned to observe the fiducials on the opposite side of the web 100 as it passes the nip roller 116. Alternatively, cameras can be positioned to observe the fiducials on the pattern after the pattern has been transferred to the substrate. By detecting the position of the fiducials, the control system 120 can determine how much the width separation of the fiducials deviates from the desired dimension. Furthermore, by measuring the movement of the web 100 between successive fiducial detections using a shaft encoder associated with the nip roller 116, the control system 120 can determine how much the length of the pattern deviates from the desired dimension.

[0078] The width of the transferred pattern can be controlled by the control system 120 by changing the temperature provided by a heating device upstream of the nip (e.g., heating roller 114), which in turn changes the temperature of the web 100 and the degree to which the web (and the pattern on it) expands when compressed onto the substrate by the nip roller 116.

[0079] The change in the length of the transferred pattern is brought about by the control system 120 by changing the tension of the web 100 immediately upstream of the nip roller 116. Tension control can be achieved by changing the relative speed and / or torque between the motor driving the nip roller 116 (one of them if the nip is formed in pairs) and the tensioning roller 110. "Immediately" means that the change is made by the control system before the web enters, although it does not necessarily have to be instantaneous or an exact preceding point. The nip is executed at a time and / or location close enough to this event so that the controlled effect persists to a sufficient extent to the change intended by the nip.

[0080] The degree of tension that needs to be applied to the web varies depending, among other things, on the specific web, the dimensions of the pattern to be transferred and their deviation from the nominal and tolerance values, and the temperature of the web (e.g., 20°C to 80°C).

[0081] The tolerance for deviations in pattern dimensions and position may vary depending on the pattern being transferred and the parameters under consideration. For example, the tolerance for deviations from ideal dimensions (e.g., pattern length and / or width, transfer area and / or non-transfer area) or ideal position (e.g., points characterizing the pattern, substrate, or their respective centroids) may be up to 100 μm, 50 μm, 25 μm, 10 μm, 5 μm, or 1 μm in absolute terms. Alternatively, or additionally, such deviations may be expressed in relative terms from values ​​obtained from reference data, for example, within 1% of ideal dimensions and / or position, or within 0.5%, 0.25%, 0.1%, or 0.05% of relevant nominal values ​​(such as the distance between two points or the coordinates of a point).

[0082] Regardless of the tolerance range, including the ideal value, the device can correct deviations of up to twice the upper limit of the tolerance variation in any dimension, and in some embodiments, the device can correct deviations of up to 5 times, up to 10 times, or up to 20 times. For example, if a pattern can have a width of 10 μm or less of the ideal width value and a length of 50 μm or less of the ideal length value in order to maintain good condition on its intended substrate, the device is adapted to correct the width and / or length of the pattern carried by the web to within 200 μm and / or 1000 μm, respectively, of the ideal values. Considering the inclination angle of the pattern, in some cases, the device may be able to correct the mis-orientation of the pattern on a web with an alpha angle of up to 2°. In some embodiments, the device can be used to properly align patterns with angles of 1.5° or less, 1° or less, or 0.5° or less to their respective substrates. Ideally, there should be virtually no distortion (α ≤ 0.03°) between the orientation of the patterns observed on the web (or on the substrate after transfer) and the intended "reference" orientation of these patterns on their respective supports.

[0083] Although this device is shown to have two controllers 120 for symmetry, it will be understood that, in practice, if the device is designed, a single controller can be used for both webs based on data received from different cameras on each web to transfer patterns from two different webs to opposite sides of the same substrate (e.g., the same nip or two different nips).

[0084] In some embodiments, the data read by camera 122 may be encoded data written during the manufacturing of the web, indicating the length and width of the pattern measured during manufacturing, or the optimal settings for the amount of heat and tension applied to the web to achieve the desired consistent size of the pattern after transfer to the substrate. Such data only needs to be input to one side of the web, and one camera per web is sufficient.

[0085] Heat is the primary parameter that determines whether a pattern expands during transfer, and tension is the primary parameter that determines whether a conductive pattern, for example, stretches. However, these two adjustments are not independent of each other, as heating can cause the pattern to stretch and tension can cause it to shrink. Therefore, the controller must consider both the measured length and width when setting the degree of heating and the tension of the web.

[0086] The controller may include a lookup table that indicates the optimal heating and tension based on the measured width and length of the pattern on the web, or it may use a recursive algorithm to arrive at the optimal settings.

[0087] It is important to understand that the feedback loop that changes the web's heating and tension during the process may not be able to respond quickly enough to correct for dimensional changes between patterns. However, the controller can determine the heating and tension settings for the rest of the web from the readings taken at the start of the web, and can adjust the settings from the readings taken while transferring the pattern from the web to compensate for slow, long-term drifts in the measured pattern length and width.

[0088] [Overview of the method] The apparatus adapted to carry out the methods described above will be explained with reference to Figure 7. It should be emphasized that although the expected steps are assigned numbers, they do not need to be performed in numerical order.

[0089] Typically, in the first step, shown as S01 in the figure, at least one web, equipped with a pattern and a substrate to which the pattern will be transferred, is driven toward the nip, with substrates being supplied one at a time. Preferably, the web and substrates are pre-aligned before entry. The web is inserted into the nip and its lateral edges are positioned relative to the nip by a web guide system, while the substrates are positioned by a substrate alignment device.

[0090] As described in the apparatus description, this step may include substrate inspection, substrate selection / rejection, and / or substrate heating. Furthermore, if a misalignment between the pattern and the substrate is detected at a later stage, the substrate feed can be changed as part of measures to gradually correct such misalignment. For example, the substrate can be accelerated or decelerated as needed until the speeds of the web and the substrate match again, and the substrate can also be tilted during alignment to match any distortion in the orientation of the pattern on the web.

[0091] In step S02, the dimensions (length and / or width) of the pattern on the web are determined before the web enters the nip. This step involves data acquisition, which can be performed by any suitable sensor adapted to detect fiducials present in the elements of the pattern or in areas of the web other than the pattern, after which the acquired data is analyzed and an action is derived accordingly.

[0092] The sensors and markings must be mutually compatible, and optical sensors are typically used for optically detectable markings. This step can be used to read data encoded in the web during web manufacturing (encoded data that sets the recommended tension and / or temperature for each web), or it can be a combination of approaches that combine recommended initial values ​​during the manufacturing phase with values ​​obtained from measurements actually performed when the web is sent to the nip. This step can be partially or entirely omitted and replaced by step S05 described below, in which similar data acquisition and analysis (simply called measurement) can be performed once the pattern has been transferred onto the substrate.

[0093] Assuming that measurements of the pattern were taken on the web in step S02, the measured length and / or width are compared to the ideally desired values ​​(reference data) (see step S06), and if there is a deviation, the tension and / or temperature of the web before entering the nip can be adjusted accordingly (see step S03). Such adjustments can be made even if the difference between the measured and target values ​​is within an acceptable range (e.g., to avoid or limit future deviations). For brevity, as illustrated in relation to Figure 5, the procedure refers to the measurement of length and / or width (or comparison thereof to reference values), but in some cases it may be desirable to evaluate additional characteristics of the pattern, such as the position of the centroid of the pattern (point E in Figure 5), the relative position of the pattern, with respect to the edges of the web (especially when margins need to be avoided in order to transfer to the appropriate area of ​​the substrate), and the inclination of the pattern from the reference direction of the reference pattern (if any). Furthermore, step S02 refers to measuring dimensions characterizing the pattern on the first web (such as length, width, centroid position, pattern inclination, and position relative to the web's edge or lateral margin), but in the subsequent step S03, when setting the web tension and / or temperature in accordance with these measurements, further consideration may be given to measurements taken with respect to the substrate onto which the pattern is transferred, and similar measurements taken with respect to the second pattern held by the second web and intended to be transferred to the opposite side of the substrate (if applicable). If there are two webs, it is advantageous to set the substrate at an intermediate distance between the two patterns (if each is offset relative to its intended position), since the substrate can only be aligned with both once. This allows the absolute deviation of each pattern relative to the substrate to be halved.

[0094] The web tension and / or temperature (related to S03) settings can initially be made empirically or based on input from the web manufacturer, but this primary feedforward control is often insufficient to account for the continuous changes in pattern dimensions and the gradual draft of transfer accuracy. Subsequent modifications of such initial settings are performed as a feedback mechanism based on measurements of the pattern on the web (S02) or after the transfer of the pattern from the web to each substrate at the nip (S04), for example, the actual length and width of the pattern are measured (data acquisition and analysis) while it is being transferred to the substrate (S05). If necessary, pattern measurements can be performed both before (S02) and after (S05) the transfer. As described in S02, the dimensions characterizing the pattern on the first surface of the substrate (e.g., length, width, centroid position, pattern inclination, position relative to the edge or lateral margin of the substrate) can be compared not only to their respective reference values ​​but also to similar values ​​measured for the pattern on the substrate to which the pattern is transferred and / or on the second surface of the substrate.

[0095] If web tension and / or temperature control is performed in accordance with measurements taken on the substrate after transfer (step S05), the measured, for example, length and / or width are compared with reference data in step S06, and if there is a deviation, the web tension and / or temperature before entering the nip may be adjusted accordingly (see step S03).

[0096] When the dimensional measurements characterizing the pattern on the web (performed in S02) and / or the pattern on the substrate (performed in S05) are compared with the measurements indicating the position of the substrate, the pattern fits to the desired value (e.g., spacing). However, if, for example, the substrate needs to be advanced or delayed relative to the pattern thanks to step S03, the corrective action in the subsequent step S01 may further include slowing or accelerating the substrate upstream of the nip to ensure correct alignment between the pattern and the substrate.

[0097] As described separately, if the deviation from the desired output is related to the relative Y position and / or orientation of the pattern with respect to the web or substrate (if no corrective action is performed), step S01 (or any step after the problem is discovered) may instead (or additionally) include moving and / or tilting the substrate laterally so that it enters the nip at a desired Y position or tilt angle that substantially matches the corresponding position or tilt angle of the orientation of the pattern on the web.

[0098] In summary, the precautions or corrective measures that can be performed by this method before entering the nip include, in addition to the basic steps of A] feeding the web and substrate to the nip (S01) and B] controlling the tension and / or temperature of the web (S03), one or more of the following steps: a) adjusting the lateral position of the web (e.g., by operating a web guide system); b) adjusting the lateral position of the substrate (e.g., by operating a substrate alignment system that uniformly changes the Y position of the substrate along the length of the substrate); c) adjusting the leading edge position of the substrate (e.g., by changing the speed of the substrate); d) adjusting the orientation of the substrate (e.g., by operating a substrate alignment system that differentially changes the Y position of the substrate along the length of the substrate).

[0099] Each of the aforementioned potential (e.g., responsive) actions does not necessarily have to completely eliminate harmful deviations from the desired parameter, as long as it is sufficient to reduce such deviations so that they fall within an acceptable range of variation from the desired value. In some cases, it may be desirable to combine two or more corrective measures to bring the deviation within an acceptable range. In that case, not all of the combined measures need to be individually effective, as long as their combined effect is sufficient to reduce the deviation.

[0100] [Example of applicability] The transfer processes enabled by the apparatus and associated methods described above are suitable for rigid or flexible, planar or curved substrates, the exact properties of which are selected depending on the article to be manufactured. Substrates for transferring functional patterns used in the manufacture of electronic components are any substrate suitable for the manufacture of a variety of products, such as printed circuit boards (PCBs), integrated circuits (ICs), radio frequency identification (RFID) tags, liquid crystal displays (LCDs), waveguides, thin-film devices, and photovoltaic (solar) cells. Such substrates are known to experts in the relevant fields and do not need to be described in detail herein. Substrates for transferring decorative patterns are less limited, as long as they are compatible with the apparatus and methods taught in the present invention.

[0101] Examples of substrates suitable for solar cell manufacturing include single-junction and multi-junction, rigid wafers and flexible thin films, which are typically made from semiconductor materials including organic and inorganic semiconductors, such as silicon (crystalline or amorphous), gallium arsenide (e.g., single-junction GaAs cells), cadmium telluride (CdTe), copper indium selenide (CuInSe), perovskite materials (with a crystalline structure of formula ABX3, e.g., titanium dioxide calcium (CaTiO3)), and copper indium gallium selenide (CIGS). Some materials are further doped or passivated in specific photovoltaic cells. The thickness of such substrates can be as low as a few nanometers (nm) to tens of micrometers in the case of thin films, which overlap with thin wafers (e.g., about 25 μm thick), and more commonly, wafers do not exceed 1 millimeter in thickness, preferably thinner than 500 μm or 250 μm. As is easily understood, some of the aforementioned substrates are relatively fragile and brittle when rigid, making it difficult to develop apparatus and methods for properly transferring patterns without damaging the substrate.

[0102] In addition to the features disclosed in the attached claims, the following clauses describe features that are considered inventive in themselves, providing a fair basis for finally filing one or more divisional patent applications.

[0103] [Clause] 1. A method for transferring a pattern supported on a web of deformable plastic material to a substrate in a transfer nip equipped with a rotatable nip roller, where the web and the substrate are pressed together, and then conforming the pattern to a desired length and / or width, a) Data showing at least one of the length and width of the pattern, (i) on the web before transferring the pattern to the substrate, and / or (ii) A step of collecting the pattern on the substrate after transferring it to the substrate, b) A method comprising the step of controlling at least one of the web temperature and tension upstream of the nip or in the nip based on collected data.

[0104] The method of Section 2.1, wherein the transfer nip is defined between a rotating nip roller and a fixed backing support.

[0105] The method of Section 3.1, wherein the transfer nip is defined between the nip roller and a second nip roller that can rotate in the opposite direction.

[0106] 4. A method according to any one of items 1 to 3, wherein the temperature and / or tension of the web is controlled by a control unit that operates at least one of a web heater and a web tension adjuster in accordance with data collected with respect to the length and width of the pattern.

[0107] 5. A method according to any one of the items 1 to 4, wherein data indicating the length and / or width of the pattern is collected by at least one sensor positioned along the web upstream and / or downstream of the nip.

[0108] The method according to Section 6.5, wherein at least one of the sensors is an optical sensor.

[0109] The method according to Section 7.5 or Section 6, wherein data indicating the length and / or width of the pattern is obtained from sensors of the pattern elements or from detections by each sensor.

[0110] A method according to any one of sections 8.5 to 8.7, wherein data indicating the length and / or width of the pattern is obtained from a fiducial sensor different from the pattern or from detection by each sensor.

[0111] A method according to any one of sections 9.5 to 9.8, further comprising providing a shaft encoder associated with a nip roller, the encoder being able to measure the movement of the web and substrate through the nip, and the length of the web passing through the nip during detection of a specific series of markings by an optical sensor indicating the length of the pattern on the web or substrate.

[0112] 10. A method according to any one of the items 1 to 9, wherein the length and / or width of a pattern is measured during the manufacturing of the web, data indicating the optimal temperature and tension of the web when transferring the pattern to a substrate is placed on the web, and at least one of the temperature and tension of the web upstream of the nip or at the nip is controlled when transferring the pattern to the substrate based on the data read from the web.

[0113] 11. A method according to any one of items 1 through 10, wherein the tension of the web is controlled by changing the speed or torque of a motor that drives two spaced-apart rollers that serve to advance the web.

[0114] 12. A method according to any one of Clauses 1 to 11, wherein a substrate is supplied to a nip by a substrate supply device and a drive mechanism for transporting the substrate to a nip, the substrate is aligned before entering the nip, and the method optionally includes, before entry, one or more of the following steps: a) inspecting the substrate for defects; b) selecting a substantially defect-free substrate; c) changing the speed of the substrate (for example, accelerating if a defective substrate is removed in the previous selection step); and d) heating the substrate.

[0115] The method of section 13.12, wherein the substrate alignment includes at least setting the Y position of the substrate with respect to the nip and / or rotating the substrate, and the alignment is optionally performed by a lateral contact.

[0116] 14. The method described in Clause 12 or Clause 13, wherein the substrate is accelerated or decelerated before entering the nip and aligned with the pattern as it enters the nip.

[0117] 15. Any method of clauses 1 through 14, further comprising guiding the web laterally before entering the nip.

[0118] 16. Any method of any of the provisions of Clauses 1 to 15, further comprising transferring the pattern to a substrate and then cooling the web and / or substrates downstream of the nip while they remain in adhesion to each other, the method optionally comprising slitting the web between one or more substrates.

[0119] 17. A method according to any one of the provisions of Clauses 1 to 16, further comprising peeling off a web from a substrate after transferring a pattern to a substrate.

[0120] 18. A method according to any one of the provisions 1 to 17, wherein the pattern comprises at least one transferable composition supported within and / or within recesses on a first surface of a web, the web being formed from one or more layers of plastic material, and at least the first surface being formed from a compatible thermoplastic polymer.

[0121] The method of section 19.18, wherein each transferable composition comprises particles of one or more materials and an adhesive that can be activated by heat and / or pressure before or during passage through the nip.

[0122] 20. The method according to claim 19, wherein at least one transferable composition comprises particles made of a conductive material.

[0123] A method according to Section 21.20, further comprising imparting conductivity to the pattern or a portion thereof, which includes particles made of a conductive material, the step of which includes sintering and / or fusing the pattern transferred to the substrate.

[0124] 22. An article comprising a pattern coated on a substrate, wherein the pattern is aligned to a desired length and / or width and is offset by no more than 100 μm and / or 1% from the desired length and / or width, respectively, and the article is manufactured using the apparatus and / or methods described in the clauses and claims and substantially detailed in this teaching.

[0125] Articles of section 23.22, wherein the pattern further coincides with a desired position on the substrate, and is offset from there by no more than 100 μm and / or 1% of the desired coordinates of each point indicating the pattern.

[0126] 24. Articles relating to Clause 22 or Clause 23, wherein the pattern further conforms to the desired direction relative to the substrate and is deviated from there by no more than 3 degrees.

[0127] For clarity, it is understood that certain features of the Disclosure described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the Disclosure described in the context of a single embodiment for the sake of brevity may also be provided separately, in any suitable subcombination, or in other described embodiments of the Disclosure. Certain features described in the context of different embodiments are not considered essential features of those embodiments unless the embodiments would not function without those elements.

[0128] Although the present invention has been described in relation to various specific embodiments for illustrative purposes only, such specifically disclosed embodiments should not be considered limiting. Those skilled in the art will be able to conceive of many other alternatives, modifications, and variations of such embodiments based on the applicant's disclosure herein. Therefore, the present invention is intended to encompass all such alternatives, modifications, and changes and is constrained only by any changes that fall within the scope of the terms and claims of this disclosure, as well as their meaning and equivalence.

[0129] In the description and claims of this disclosure, the verbs “including,” “including,” and “having” and their conjugations are used to indicate that the subject matter of the invention is not necessarily a complete list of features, members, steps, components, elements, or parts of the subject of the verb. Nevertheless, the methods of this teaching are intended to consist essentially of, or be composed of, the described process steps, and the apparatus of this teaching is intended to consist essentially of, or be composed of, the described devices.

[0130] In this specification, the singular forms "a," "that," and the definite article refer to the plural form and mean "at least one" or "one or more" unless the context explicitly indicates otherwise. In this specification, the expression "at least one of A and B" means either A or B, and in some examples, it may mean both A and B.

[0131] Terms describing position or action, such as “up,” “down,” “right,” “left,” “bottom,” “down,” “lowered,” “lower,” “up,” “up,” “higher,” “vertical,” “horizontal,” “backward,” “forward,” “upstream,” and “downstream,” as well as their grammatical variations, may be used herein for illustrative purposes only to indicate the relative position, arrangement, or displacement of a particular component, to show a first component and a second component, or both, in this figure. Such terms do not necessarily indicate, for example, that a “down” component is below a “up” component. Such directions, components, or both, may be reversed, rotated, moved in space, positioned in an oblique direction or location, positioned horizontally or vertically, or similarly altered.

[0132] Unless otherwise specified, the expression "and / or" between the last two members of a list of selection options indicates that it is appropriate and possible to select one or more of the listed options.

[0133] The term “exemplary” as used herein means “serving as an example, case, or illustration.” Embodiments described as “exemplary” should not necessarily be interpreted as being preferable or advantageous to other embodiments, and / or preclude the incorporation of features from other embodiments.

[0134] Where used herein, unless otherwise specified, adjectives such as “substantially,” “approximately,” and “about,” which modify the state or relational characteristics of features or groups of features in embodiments of the Art, should be understood to mean that the state or characteristic is defined within the permissible range for the operation of the embodiment in which it is intended, or within the range of variation expected from the measurements performed and / or the measuring instruments used. Where the terms “about” or “approximately” precede a number, it is intended to indicate only + / -15%, + / -10%, or + / -5%, and in some cases, the exact value. Furthermore, unless otherwise stated, terms used in this disclosure (e.g., numbers) should be interpreted as having a permissible range that allows the invention or relevant parts thereof to operate and function as described and as understood by those skilled in the art, even without such adjectives, although they may deviate from the exact meaning of the related terms. Unless otherwise specified, where outer boundaries relating to the scope of features of embodiments of the Art are described in the disclosure, it should be understood that in that embodiment, the possible values ​​of the feature may include not only the described outer boundaries but also the values ​​between the described outer boundaries.

[0135] To the extent necessary to understand or complete this disclosure, all publications, patents, and patent applications referenced herein, in particular, including the applicant's applications, are expressly incorporated in their entirety by reference as they are fully described herein.

Claims

1. An apparatus for transferring a pattern (410) supported on a web (14, 100) made of a deformable plastic material to a substrate (10), comprising a nip section (40) defined between at least one nip roller (22) and a backing support (42), wherein the substrate passes through the nip section simultaneously with the web and pressure is applied by the nip section, thereby transferring the pattern (410) from the web to the substrate, wherein the apparatus comprises a web heater (114) and a web tension adjuster (110) positioned upstream of the nip section, and a control unit (120) configured to control the web heater and the web tension adjuster, wherein the control unit (120) controls the web heater and the web tension adjuster based on data indicating the length and width of the pattern on the web before transfer, or data indicating the length and width of the pattern on the substrate after transfer, thereby ensuring that the pattern conforms to a desired length and width after it has been transferred to the substrate.

2. The apparatus according to claim 1, further comprising at least one sensor (70) located upstream of the nip portion (40) for measuring the width and length of the pattern (410) on the web (14, 100) immediately before transfer.

3. The apparatus according to claim 1 or 2, further comprising at least one sensor (80) for measuring the width and length of the pattern (410) on the substrate (10) after transfer at the nip portion (40).

4. The apparatus according to claim 2 or 3, wherein each of the sensors (70, 80) includes an optical sensor (122) for determining the location of a particular marking on the web (100) on both sides of the web, the marking being a fiducial (420, 430) distinct from the pattern (410), or a component (440) of the pattern (410), thereby performing a measurement indicating the width of the pattern (410) on the web or the substrate (10).

5. The apparatus according to claim 4, wherein the nip roller (22) is associated with a shaft encoder capable of measuring the movement of the web (100) and the substrate (10) through the nip portion (40), and the length of the web passing through the nip portion (40) during the detection of a series of specific markings (420, 430) on the web by at least one optical sensor (122) indicates the length of the pattern on the web or the substrate.

6. The apparatus according to any one of claims 1 to 5, wherein the length and width of the pattern (410) are measured during the manufacture of the web (100), encoded data markings (420, 430) including data indicating the size of the pattern are applied to the web (100) during the manufacture of the web (100), and the control unit (120) of the apparatus sets the web temperature and web tension based on the data read from the web.

7. The apparatus according to claim 6, wherein the encoded data markings (420, 430) indicate optimal web temperature and web tension to be set by the control unit (120) before the transfer of the pattern (410) to the substrate (10).

8. The apparatus according to any one of claims 1 to 7, wherein the web heater is a heating roller (114) positioned upstream of the nip portion (40).

9. The apparatus according to any one of claims 1 to 8, wherein at least one of the nip rollers (22) is equipped with a heater.

10. The apparatus according to any one of claims 1 to 9, wherein the web tension is variable by controlling the speed or torque of a motor that drives two spaced-apart nip rollers (22) for advancing the web (14, 100).

11. The apparatus according to any one of claims 1 to 10, wherein the backing support (42) is a second nip roller (22).

12. Upstream of the aforementioned nip portion (40), a) Web guidance system (17); b) substrate supply device (12); c) A drive mechanism (90) for transporting the substrate (10) to the nip section (40); d) PCB inspection station (60); e) Board selection station (62); f) Board speed change station (64); g) Substrate heating station (52); and h) The apparatus according to any one of claims 1 to 11, further comprising at least one of a substrate alignment device (50) capable of displacing the substrate in the lateral and / or rotational direction relative to the nip portion.

13. Downstream of the nip portion (40), i) A cooling station (23) for cooling the web (14, 100) and / or the substrate (10) in contact with each other; ii) Separation device (30) for peeling the web from the substrate; iii) A cutting device for slitting the web between one or more substrates; and The apparatus according to any one of claims 1 to 12, further comprising at least one of iv) a finishing station.

14. The apparatus according to any one of claims 1 to 13, wherein the pattern (410) comprises at least one transferable composition supported in and / or on a recess of the first surface of the web.

15. The apparatus according to claim 14, wherein the web (14, 100) is made of one or more layers of plastic material, and at least the first surface is made of a moldable thermoplastic polymer.

16. The apparatus according to any one of claims 1 to 15, wherein the pattern (410) comprises one or more transferable compositions, the transferable composition comprising particles of one or more materials and an adhesive that can be activated by heat and / or pressure.

17. The apparatus according to claim 16, wherein the pattern (410) is conductive or can be made conductive, and at least a portion of the particles is made of an electrically conductive material.

18. A method for transferring a pattern supported on a web made of a deformable plastic material to a substrate in a transfer nip equipped with a rotatable nip roller and in which the web and the substrate are pressed against each other, and then conforming the pattern to a desired length and / or width, a) Data indicating at least one of the length and width of the pattern, (i) on the web before transferring the pattern to the substrate, and / or (ii) Collecting on the substrate after transferring the pattern to the substrate, and b) A method comprising controlling at least one of the temperature and tension of the web upstream of the nip and / or in the nip, based on the collected data.

19. The method according to claim 18, wherein the data indicating the length and / or width of the pattern is collected by at least one sensor positioned along the web upstream and / or downstream of the nip.

20. The method according to claim 19, wherein the data indicating the length and / or width of the pattern is derived from the detection by each of the sensors of two or more markings selected from the components of the pattern and fiducials distinct from the pattern.

21. The method according to any one of claims 18 to 20, further comprising providing a shaft encoder associated with the nip roller, the shaft encoder being capable of measuring the movement of the web and the substrate through the transfer nip, and the length of the web passing through the nip during the detection of a particular series of markings indicating the length of the pattern on the web or the substrate.

22. The method according to any one of claims 18 to 21, wherein the length and / or width of the pattern is measured during the manufacture of the web, data indicating the optimal web temperature and web tension for transferring the pattern to the substrate is applied to the web, and at least one of the web temperature and web tension upstream of the transfer nip and / or at the transfer nip is controlled based on the data read from the web during the transfer of the pattern to the substrate.

23. a) The change in web temperature is controlled by heating the web upstream of and / or in the transfer nip, and / or b) The change in web tension is controlled by changing the speed or torque of a motor that drives two spaced-apart rollers that advance the web toward the nip.

24. The method according to any one of claims 18 to 23, wherein the substrate is supplied to the nip by a substrate supply device and a drive mechanism for transporting the substrate to the transfer nip, and in the transfer nip, the substrate is aligned before it enters the nip, and prior to the entry, one or more of the following are optionally included: a) inspecting the substrate for defects, b) selecting a substantially defect-free substrate, c) changing the speed of the substrate, and d) heating the substrate.

25. The method according to claim 24, wherein the alignment of the substrate includes setting at least the Y position of the substrate with respect to the transfer nip and / or rotating the substrate, and the alignment is optionally performed by a lateral contact member.

26. The method according to any one of claims 18 to 25, further comprising guiding the web laterally before entering the transfer nip.

Images