Guided transport route correction

Abstract

To provide suitable guided transport path correction. As part of a manufacturing process for electronic products, a printer deposits material onto a substrate, and at least one transported component is subject to errors that affect deposition. These errors are mitigated using transducers that uniformly position the component, for example, to provide an "ideal" transport path, thereby enabling precise drop placement despite the errors. In one embodiment, optical guides (e.g., using lasers) are used to define the desired path, and sensors mounted on the component dynamically detect deviations from this path, which are then used to drive the transducers to counteract the deviations in real time. This error correction scheme can be applied to correct for more than one type of transport error, for example, to correct for errors in the substrate transport path, the printhead transport path, and / or split-axis transport non-orthogonality.

Description

[Technical Field]

[0001]

[0001] This disclosure claims the benefit of U.S. Patent Application No. 15 / 642,188, filed July 5, 2017, on behalf of first named inventor Eliyahu Vronsky, entitled "Guided Transport Path Correction," U.S. Provisional Application No. 62 / 489,768, filed April 25, 2017, on behalf of first named inventor Digby Pun, entitled "Transport Path Correction Techniques And Related Systems, Methods And Devices," and U.S. Provisional Application No. 62 / 359,969, filed July 8, 2016, on behalf of first named inventor Digby Pun, and U.S. Provisional Patent Application No. 62 / 459,402, filed February 15, 2017, on behalf of first named inventor David C. Darrow, entitled "Precision Position Alignment, Calibration and Measurement in Printing And Manufacturing Systems," each of which is incorporated herein by reference.This disclosure also incorporates the following documents: U.S. Patent No. 9,352,561 (USSN 14 / 340403), filed as an application on July 24, 2014, on behalf of first inventor Nahid Harjee, for "Techniques for Print Ink Droplet Measurement And Control To Deposit Fluids Within Precise Tolerances"; U.S. Patent Publication No. 20150360462 (USSN 14 / 738785), filed as an application on June 12, 2015, on behalf of first inventor Robert B. Lowrance, for "Printing System Assemblies and Methods"; and U.S. Patent Publication No. 20150298153 (USSN 14 / 738785), filed as an application on June 30, 2015, on behalf of first named Michael Baker, for "Techniques for Arrayed Printing of a Permanent Layer with Improved Speed ​​and Accuracy." No. 14 / 788609, and U.S. Patent No. 8,995,022, filed as application on August 12, 2014, on behalf of first named inventor Eliyahu Vronsky, for "Ink-Based Layer Fabrication Using Halftoning To Control Thickness." [Background technology]

[0002] One type of industrial printer can be applied to precision manufacturing, for example, the fabrication of electronic devices.

[0003] To take one non-limiting example, an inkjet printer can be used to deposit one or more ultra-thin layers for an electronic display device or a solar panel device. The "ink" in this case differs from the traditional concept of ink as a dye of a desired color; instead, it can be an organic monomer that diffuses and mixes together somewhat but is not absorbed; instead, it can be deposited as discrete droplets that maintain an intentional layer thickness that serves to impart structural, electromagnetic, or optical properties to the finished device. Inks are also typically intentionally made translucent, and the resulting layer is used to generate and / or transmit light. The continuous coat of ink deposited by printing is then processed in place (e.g., cured using ultraviolet light or otherwise baked or dried) to form a permanent layer with a very tightly controlled thickness, e.g., 1 to 10 microns, depending on the application. These types of processes can be used to deposit various conductors, such as hole injection layers ("HIL"), hole transport layers ("HTL"), emissive or emissive layers ("EML"), electron transport layers ("ETL"), electron injection layers ("EIL"), anode or cathode layers, hole blocking layers, electron blocking layers, polarizers, barrier layers, primers, encapsulation layers, and other types of layers of an OLED pixel. The referenced materials, processes, and layers are merely exemplary. In one application, the ink can be deposited to create a layer within each of many individual electronic components or structures within individual microscopic fluid reservoirs (e.g., within "wells") to form individual display pixels or solar cell layers, for example. In another application, the ink can be deposited to form one or more encapsulation layers having macroscopic dimensions, for example, covering many such structures (e.g., spanning the area of ​​a display screen having millions of pixels).

[0004] The required precision can be very fine; for example, a manufacturer's specifications for fabricating thin layers of organic light-emitting diode ("OLED") pixels may specify condensed fluid deposition within pixel wells to picoliter resolution (or even to higher levels of precision). Even slight local variations in deposited fluid volume from specification can create problems. For example, variations in ink volume between structures (e.g., between pixels) can result in hue or intensity differences or other performance discrepancies that are noticeable to the human eye. In encapsulation or other "macroscopic" layers, such variations can impair layer function (e.g., a layer may not reliably seal electronic components sensitive to unwanted particulate matter, oxygen, or moisture) or otherwise cause observable differences. As devices become increasingly smaller, these problems become even more significant. It should be appreciated that a typical application may feature a printer with tens of thousands of nozzles depositing discrete droplets, each having a volume of 1 to 30 picoliters (“pL”), and that when one considers that manufacturing process corners for printheads can lead to inoperable nozzles and individual errors in droplet size, nozzle location, droplet velocity, or droplet landing position, thereby causing local ink volume delivery variations, there is an enormous challenge in producing thin, homogenous layers that closely follow the desired manufacturing specifications.

[0005] One source of error in achieving fine precision relates to the use of mechanical components in the fabrication process relative to the scale of the product being manufactured. As a non-limiting example, most printers have a mechanical transport system that moves one or more print heads, the substrate, or both to perform printing. Some printers may also feature transport systems for rotating or offsetting components (e.g., moving or rotating the print head to change the effective pitch between nozzles), each of which can impart fine mechanical or positioning errors and, in turn, lead to nonuniformity. For example, even if these transport systems typically rely on high-precision components (e.g., precision tracks or edge guides), they can still impart jitter or translational or rotational inaccuracies (e.g., deviations on the scale of millimeters, microns, or smaller within the transport path) that make it difficult to achieve the required precision and uniformity throughout the transport path length used in production. To provide context, equipment used to fabricate large HDTV screens may feature "room-sized" printers controlled to deposit ultrathin layers of material onto meter-wide by meter-long substrates, with individual droplet delivery planned to nanometer-scale coordinates. Transport paths within such equipment can be meters in length. It should be noted that there are many other mechanical components in such systems that can introduce some form of error, such as transport path systems used to exchange printheads, camera assemblies that align or inspect substrates, and other types of moving parts. Even mechanical parts with very fine precision in such systems can generate deflections that affect the nanometer-scale coordinates referenced above. Thus, as the layers required become thinner and thinner and the precision required becomes smaller and smaller relative to the products being fabricated, carefully controlling and / or mitigating potential sources of positional error becomes even more essential.

[0006] Generally, there are several conventional techniques for reducing position and translation errors in these types of processing systems. First, the substrate can be roughly aligned with the printer transport and then finely aligned manually (potentially repeatedly during the processing process). Such a process is time-consuming, i.e., it generally hinders the goal of having an automated, high-speed assembly-line-type process for producing consumer products. It is also generally extremely difficult to obtain the required micron or nanometer accuracy using such a manual process. There are also some errors that cannot be adequately addressed using such techniques, such as errors caused by differences in the transport path as just introduced above (e.g., errors that appear after the substrate is aligned). As a second example, U.S. Patent Publication No. 20150298153 relates to a process for measuring fine position and / or rotation errors in substrate position and correcting these errors in software, for example, by reallocating the nozzles used to print or by otherwise changing the nozzle drive waveforms used to fire the nozzles. In other words, generally speaking, these techniques attempt to "live with" minute position and rotation errors (thereby preserving printing speed) and then adjust the nozzles used, and the time and manner in which those nozzles are electronically controlled, to correct for the errors (e.g., using pre-planned rasters without having to readjust error-dependent scan paths). However, despite the usefulness of compensating for alignment errors in software, measuring and accounting for these errors in software and recalculating firing assignments for thousands of nozzles can require significant computational resources and time.

[0007] What is needed are additional techniques for correcting motion, rotation, and position errors in mechanical systems within manufacturing equipment. What is still further needed are techniques for correcting errors in moving components of manufacturing systems to simulate an "ideal" edge or transport path. Such techniques, when applied to precision manufacturing processes, and particularly to printing systems of the type described, would reduce the need for significant computational resources and time to re-render raster control data, leading to an overall simpler and / or faster and / or more accurate printing process. The present invention addresses these needs and provides further related advantages. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 illustrates a substrate 103 as it is transported through an industrial printing system along a transport path 107. To its right, FIG. 1 shows the substrate in two hypothetical positions (103′ and 103”) with respective rotational and translation errors (Δx, Δy, and Δθ). The transport path errors and associated substrate rotational and translation errors are considered exaggerated relative to the scale of the drawing to aid in illustration.

[0009] [Figure 2A] 2A is a schematic diagram of a system 201 for dynamically correcting mechanical errors. A first component 203 travels along a transport path 206 (generally aligned with the "y" axis in this example), mirrors 211 / 212 and sensors 208 / 209 detect deviations from an optical guide 202 (e.g., a laser beam), and during the first component's travel, transducers 216 and 217 are automatically actuated in response to signals from sensors 208 / 209 to equalize deviations (e.g., in one or more dimensions, such as x, z, and / or θ) so that a second component 205 follows an ideal path despite mechanical errors.

[0010] [Figure 2B]FIG. 2B is a flow chart associated with correcting position and / or rotational errors as a transported component is advanced along a transport path.

[0011] [Figure 3A] Figure 3A is a schematic diagram showing one or more transducers that perform fine mechanical adjustments and correct for the errors referenced in relation to Figure 1 (i.e., in this example, as part of the "gripper" that advances the substrate). As will be described, an optical guide such as a laser source 319 can be used to define a desired path, and deviations from this path are sensed by one or more sensors 320. One or more transducers "T" are actuated in response to this deviation, with the result (in this example) that the substrate travels a "perfectly straight" or "jitter-free" transport path.

[0012] [Figure 3B] Figure 3B depicts a transport path 107 with mechanical imperfections similar to Figure 1. However, in this case, a transducer "T" as introduced relative to Figure 3A is used to perform fine adjustments of the substrate position and / or orientation as the gripper advances on the path 107. The result is that the substrate now moves according to an "ideal" motion (e.g., a perfectly straight "ideal" edge and / or a path without jitter), as represented by the imaginary straight edge 323.

[0013] [Figure 3C] Figure 3C is similar to Figure 3B in that it illustrates the use of a transducer "T" to correct for transport path error. However, in this case, error also potentially arises from a second transport path 356, which in this case exhibits a non-ideal position or orientation of the print head (or camera or other assembly) as it is transported in the general direction of arrow 354.

[0014] [Figure 3D]FIG. 3D is similar to FIG. 3C in that it depicts the movement of the print head along edge or track 356, but as shown, the print head assembly now also has its own optical guide 371 and transducer assembly to provide fine position and rotation corrections that mitigate errors in edge or track 356, the result being that the print head now also effectively travels a virtual "ideal" path 325 (or 369, as will be discussed below).

[0015] [Figure 3E] Figure 3E is similar to Figure 3C in that it depicts the motion of the print head along an edge or track 356. However, while the print head transport path has optical guides, corrections to match print head jitter are instead applied by a transducer-based error correction system associated with another transport path, in this case, transducers associated with the gripper.

[0016] [Figure 3F] FIG. 3F is an illustrative diagram showing a mechanism for correcting transport path errors, for example, by implementing compensatory counter-motions (or other error mitigation) in up to six different degrees of freedom (e.g., potentially including three translational degrees of freedom, plus yaw, pitch, and / or roll).

[0017] [Figure 4A] 4A provides a plan view of a substrate and illustrates the raster or scanning process. Shaded areas 407 represent a single scan path, while transparent areas 408 represent alternative paths. As indicated by the dimension legend in the figure, in this example, the "x" axis corresponds to the cross-scan dimension, while the "y" axis corresponds to the in-scan dimension.

[0018] [Figure 4B] FIG. 4B provides a top schematic view of a processing machine that includes multiple modules, one of which (415) features a printer within a controlled atmosphere.

[0019] [Figure 4C] FIG. 4C is a block diagram illustrating one method 431 for dynamically correcting transport path errors in an industrial printing system.

[0020] [Figure 5] FIG. 5 is an illustrative diagram showing a series of optional layers, products, or services that can each independently embody the techniques introduced herein; for example, these techniques can be implemented in the form of software (by numeral 503), or as printer control data (by numeral 507) used to control a printer to print on a substrate or otherwise correct errors, or as products made relying on these techniques (e.g., as exemplified by numerals 511, 513, 515, or 517).

[0021] [Figure 6A] FIG. 6A is a detailed perspective view of one embodiment of an industrial printer, such as the printer inside the print module of FIG. 4B.

[0022] [Figure 6B] FIG. 6B is a detailed perspective view of an embodiment of a gripper.

[0023] [Figure 6C] FIG. 6C is a close-up perspective view of the transducer assembly from the gripper of FIG. 6B.

[0024] [Figure 6D] FIG. 6D is a close-up perspective view of a floating mechanical pivot assembly from the gripper of FIG. 6B.

[0025] [Figure 6E] FIG. 6E is a schematic perspective view of the error correction system represented by FIGS. 6B-6D, with emphasis on the design of the floating mechanical pivot assembly.

[0026] [Figure 7A]FIG. 7A shows an embodiment 701 in which an optical guide 702 is used to ensure linear motion of a gripper 703 and a substrate 704 .

[0027] [Figure 7B] FIG. 7B shows an embodiment 713 in which the laser source and / or light redirecting optics are mounted on an offsettable component of the gripper or other element being transported.

[0028] [Figure 7C] FIG. 7C shows an embodiment 719 in which a sensor 720 is used to calibrate a light source 721, for example, to detect and / or correct a path error 722 relative to an intended path 723.

[0029] [Figure 7D] Figure 7D shows an embodiment 727 in which the light source 728 is improperly aligned. However, unlike the embodiment of Figure 7C, the deviation between the incorrect optical path 729 and the correct optical path 730 is corrected electronically by using transducers (represented by arrow icons 732A / 732B) to implement compensating offsets. The signals controlling these offsets can be stored in digital memory and read out during system operation, or otherwise added to dynamic corrections depending on the transport path position so that the transported component follows the correct path 730.

[0030] [Figure 7E] 7E shows an embodiment 735 that implements a zero target control loop. Sensors 736A / 736B dynamically detect deviations from a desired path in one or more dimensions (in this case, represented by the deviation between a "line of sight" 737A / 737B and a beam 738 from a laser source 739). A motion controller 741 provides feedback that drives transducers 742A / 742B to constantly drive the error to zero.

[0031] [Figure 7F]7F shows an embodiment 745 in which transducers 746A / 746B are driven to maintain the transported object (e.g., gripper 747 and substrate 748) always horizontal with respect to optical guide 749. In this case, sensors 750A / 750B detect deviations of portions of the substrate and / or gripper from optical guide 749 and drive the two transducers 746A / 746B to even out jitter in altitude or otherwise precisely control the altitude.

[0032] [Figure 7G] 7G shows an embodiment 755 using two parallel transport systems 756A / 756B for a given transport direction. In this case, each transport system has its own optical guide 757A / 757B and transducer compensation system 759A / 759B. One of the transport systems 756B also carries another light source 765 that generates an optical guide 766 used to align and synchronize the two transport systems 756A / 756B. A signal from a detector 767 on the second transport system 756A is fed to a motion controller 763 to maintain synchronization between the transport systems.

[0033] [Figure 7H] 7H shows an embodiment 771 in which two transport systems 772 and 773 each have their own source 774 / 775 and motion controller 780 / 781. The result is that errors are corrected transparently to the general system motion control so that each motion controller 780 / 781 receives an individual (absolute position coordinate) command signal 782 / 783 and can establish the appropriate position relative to the system coordinate reference system.

[0034] [Figure 7I]7I shows an embodiment 787 in which two transport systems 788 / 789 each have their own source 790 / 791 and sensor pair 792A,B / 793A,B, but only one system has a transducer-based error correction system (794A / B). In this case, a motion controller 795 generates transducer control signals 796A / 796B so that one of the transport systems (789) compensates for errors associated with the other transport system 788. Non-motion errors, such as errors in alignment of the optical guides related to either the transport systems and / or non-orthogonality between the transport systems, can also be corrected.

[0035] [Figure 8A] FIG. 8A is a cross-sectional view of an assembly that uses two different sets of transducers "T" to correct errors in more than one dimension.

[0036] [Figure 8B] FIG. 8B is a cross-sectional view of another assembly that uses two different sets of transducers "T" to correct errors in more than one dimension.

[0037] The subject matter defined by the recited claims may be better understood by reference to the following detailed description, which should be read in conjunction with the accompanying drawings. The present description of one or more specific embodiments, presented below to enable one to build and use various implementations of the technology described by the claims, is intended to illustrate the applications of the recited claims, not to limit them. Without limiting the foregoing, the present disclosure provides several different examples of techniques for mitigating transport path errors in a manufacturing apparatus or printer and / or for processing thin films for one or more products on a substrate as part of a reproducible printing process. The various techniques can be embodied in various forms, for example, in the form of a printer or manufacturing apparatus or component thereof, in the form of control data (e.g., pre-calculated correction data or converter control data), or in the form of an electronic or other device processed as a result of these techniques (e.g., having one or more layers produced according to the described techniques). While specific examples are presented, the principles described herein may also be applied to other methods, devices, and systems. DETAILED DESCRIPTION OF THE INVENTION

[0038] The present disclosure provides a method for correcting transport path errors and / or providing a method for ... Improved techniques for processing layers are provided. In one embodiment, these techniques are applied to a manufacturing apparatus or system that produces layers of an electronic display, solar panel, or another electronic device, or indeed any other type of precision device or product. The manufacturing or processing system will include a transport system, and components will be guided along a transport path to support manufacturing. The path length is typically quite long relative to the required positioning accuracy. In a typical implementation, for example, the transport path length may be meters, while the required positioning may be on the micron scale or even finer (e.g., nanometer scale or finer). To support precise positioning, one or more sensors are used to detect deviations between the component and the optical beam in one or more dimensions. Deviations detected by the one or more sensors are then used to derive position correction signals that are fed to one or more transducers and used to offset the deviations, with the result that the component tracks the optical path despite fine mechanical errors associated with the transport path. In one embodiment, the one or more sensors provide feedback that forces the transducers to constantly "null" position and rotational errors.

[0039] More specifically, these techniques can be optionally applied to printers used to fabricate electronic products, where the printer deposits material onto a substrate at precise coordinates. A transport system in this context can be any mechanical system used by the printer, such as a gripper used to advance the substrate, a printhead motion system used to transport the printhead (e.g., orthogonal to the gripper motion), a camera transport system, a flight altitude or printhead altitude adjustment system, and other types of assemblies. In the discussion immediately following, examples will be described in which these techniques are applied to gripper path adjustment. It should be understood that the techniques described herein are not limited to gripper transport systems, nor are they limited to the general context of printers. Conversely, it should also be understood that these techniques can be optionally applied to two or more transport or transport systems within a manufacturing system, such as to control any of the x, y, and / or z positions or associated rotational degrees of freedom, as desired. In one embodiment discussed below, these techniques are applied independently to each of the gripper and print head transport paths and used in concert with a position feedback system for each transport path to provide precise position positioning in the x, y, and / or z axes and to ensure coordinate system orthogonality and precise position control within the printing system.

[0040] In one example, a meter-long by meter-wide glass substrate would be introduced into a "room-sized" printer, which would print individual droplets of "ink" at very precise coordinates (e.g., precise nanometer or sub-nanometer coordinates). Two transport systems are used to position the droplets: a "gripper" that advances the substrate back and forth along a "fast" or "in-scan" direction, and a printhead transport system that moves the printhead in a "slow" or "cross-scan" direction (e.g., the printhead is repositioned between subsequent scans so that printing occurs in swaths as the substrate moves beneath the printhead). In variations, both systems can be moved simultaneously, or the printhead or substrate can be stationary while the other moves in two or more dimensions. Droplet landing locations are typically selected so that the deposited droplets mix together on the glass substrate, providing gapless area coverage, forming a liquid coat without pinholes, gaps, or other defects. Unlike the traditional notion of ink for graphics printers, "ink" is typically a colorless, or alternatively described, relatively viscous material (e.g., an organic monomer) where the natural color of the material is not important. The ink is typically not absorbed and spreads only to a limited extent so that the finished layer provides a specifically desired layer thickness or other specifically desired electronic, magnetic, light-generating, structural, or similar properties. For example, the ink, in one embodiment, can be an organic monomer, and the deposited coat (once the droplets are sufficiently mixed) is then cured using ultraviolet light to form a polymer layer. Once formed, the liquid coat is then hardened, dried, cured, developed, or otherwise treated ("treated") to form a permanent or semi-permanent layer of the electronic product being fabricated on the glass substrate. These techniques can be used to deposit light-generating layers, encapsulation layers, and potentially other types of layers for individual pixels of an electronic display.For example, the techniques disclosed herein can be applied to a wide variety of manufacturing processes, including, but not limited to, the deposition of precision coatings for "smart windows" and other types of electronic, optical, or other devices. It should be noted that when used to form layers of precision electronic components (e.g., micron- or nanometer-scale structures), each droplet in the foregoing examples must typically be deposited at very fine position coordinates; for example, too much or too little ink, or a misplaced droplet, can result in a defective or suboptimal component. Precision mechanical components (e.g., tracks or edge guides) are used to help ensure accurate motion, but these systems can still introduce mechanical jitter that interferes with proper droplet placement.

[0041] In embodiments herein, to correct this problem, a transport system (e.g., a gripper) can have two components, including a first (or “track-guided”) component that moves along a transport path and a second (or “offsetable”) component, with one or more transducers used to offset the second component relative to the first component. For example, the first component follows a track, while the second component carries a vacuum chuck that is used to engage the substrate. In other embodiments, other techniques can be used to engage and / or transport the substrate. When the first component experiences jitter and error, the error is detected and used to drive a transducer that causes the second component to offset the error so that the substrate follows an ideal path. In one embodiment, this is achieved by using a laser beam and / or optics and / or detectors to mark the ideal path, and the second component mounts one or more of these optical components in a manner that detects deviations of the second component from the marked ideal path. The detected deviation is used to instantly drive a transducer to counteract the deviation. In one implementation, a simple two-cell detector can be used to detect path deviation in one dimension, while in another implementation, a four-cell or more complex design can be used to detect errors in two or more dimensions. For example, in connection with the example presented above, a glass substrate can be supported on an air bearing (i.e., above a gas floating table) while a gripper can use suction to selectively engage and then transport the substrate. The gripper's "second component," in one embodiment, can be offset in the cross-scan dimension and in altitude to match (or otherwise equalize) the substrate's flight height above the air floating table. Of course, other implementations will occur to those skilled in the art. As noted above, the techniques described herein can be applied to a wide variety of manufacturing and / or transport systems (e.g., application to printers, grippers, printheads, or similar components is considered "optimal").

[0042] It should be noted that whatever the source of the error (e.g., whether due to a "repeatable" error or otherwise to the conveying system), the techniques described herein instantly correct the position of what is being transported so that it undergoes ideal motion, at least in one or more dimensions orthogonal to the direction of transport. These techniques are particularly useful when precise position and / or orientation control is desired, for example, in assembly line type processes where each substrate or each product may be subject to minute repeatable or non-repeatable position and / or orientation errors.

[0043] To correct and / or mitigate errors, in one embodiment, fine-positioning transducers are driven without a fixed pivot point to counteract mechanical imperfections. These transducers perform fine adjustments of the substrate position and / or orientation, thereby counteracting the effects of mechanical imperfections in at least one dimension. In this way, the transport system (e.g., gripper, substrate, print head, camera, or other transport path) continues to be characterized by mechanical imperfections, but the motion of the substrate and / or print head is performed to approximate ideal progression. In one embodiment, the transport path is substantially linear, with transport occurring substantially along a first dimension (e.g., the "y" dimension), while two or more transducers each independently apply a linear offset in an independent dimension (e.g., the "x" dimension). When driven in common mode, these transducers allow for the offset of imperfections associated with the transport system that affect the "x" dimension position of the substrate. For example, a transported object can be made to travel a virtual straight edge in the "y" dimension. When driven in differential mode, the transported object can also be rotated in the "xy" plane to correct for orientation errors similarly caused by mechanical imperfections in the transport path. Note that three or more transducers can be used to simultaneously correct for errors in multiple dimensions, for example, to "equalize" gripper or printhead elevation, as will be discussed further below.

[0044] In split-axis systems used to process electronic devices on substrates, a "gripper" can be used to move the substrate along a first dimension (e.g., the "y" dimension). The gripper has a first component that rides along the edge or track and a second component (typically a vacuum device) that engages and locks onto the substrate. A transducer can be operably positioned between the first and second components to provide selective offsets between these components at two or more discrete points of interaction, providing both common-mode and differential-mode displacements as referenced above. When the first component experiences translational and rotational deflections caused by mechanical imperfections in the transport system (e.g., in the second dimension), the transducer is driven to precisely equalize these deflections in that dimension, essentially providing the second component with a "virtual edge" or "virtual transport path" that is uncharacterized by mechanical errors. Note that the errors can be linear and nonlinear, and the corrections can be correspondingly linear and nonlinear. In optional embodiments, this type of system can be embodied in a printer or printing system, for example, where the y dimension is the substrate transport dimension and / or one of the "in-scan" or "cross-scan" dimensions, and the x dimension is the print head transport dimension and / or the other of the "in-scan" or "cross-scan" dimensions. Note that the described frames of reference are arbitrary and can be inverted or exchanged for other frames of reference or other degrees of freedom.

[0045] As described, there may be multiple transport paths in a manufacturing system, and these techniques may be applied to any one or combination of these transport paths to correct for positional errors (or rotational errors) in one dimension or errors in multiple dimensions. A few examples will help to emphasize this point.

[0046] First, in one contemplated implementation, these techniques are used to correct cross-scan dimension errors in substrate position as the gripper moves along a transport path. The gripper has first and second components, as referenced above, and a linear transducer operatively coupling these components at at least two interaction points, with the transducer structured to provide a "floating" pivot point. As the first component advances along the transport path, deviations from an optical guide or desired optical orientation are detected. Signals generated from this detected deviation are used to control the transducer to provide "common-mode" and "differential-mode" offsets that repeatedly provide translational offsets or rotational adjustments of the substrate in the cross-scan dimension to drive the deviation or error toward zero. The substrate is thus advanced in a linear path despite mechanical imperfections in the transport system. Various embodiments of the described transducers will be provided below, but briefly, in one embodiment, a "voice coil" can be used for these transducers to provide very precise microscopic throws. A floating mechanical pivot assembly compatible with common and differential drive modes can also optionally be used to help provide structural support and interconnection between the first and second components. In other embodiments, piezoelectric or other transducers can be used instead.

[0047] In an optional extension to this first example, the gripper position (and / or the position of a second component of the gripper) can also be adjusted in the in-scan dimension. For example, in one embodiment, the electronic drive signal (used to advance the gripper or otherwise trigger printer nozzle firing) is adjusted to correct for substrate position error in the in-scan dimension. It is also possible to use another transducer (e.g., another voice coil or other transducer) to offset the first component relative to the second component in the in-scan dimension. In a first technique, the in-scan position error can be measured and used to offset individual nozzle firings (i.e., as the printhead and substrate move relative to each other to achieve nozzle firing at a precisely corrected intended in-scan position). For example, a nozzle firing delay can be calculated and programmed into the printhead for each nozzle, and firing is then driven from a common trigger signal. In a second technique, a common nozzle trigger signal or a shared nozzle trigger signal can be generated as a function of the gripper position (and / or the position of the first component of the gripper) and can be corrected for error so that the trigger signal is generated to simulate error-free movement of the gripper. Regarding this optional extension, it has already been described that in one implementation, the correction technique can be applied to each of the gripper and printhead transport path and used in concert with a position feedback system for each transport path to provide precise positioning in the x and y axes and ensure coordinate system orthogonality and precise position control within the printing system. In one such implementation, the gripper system has a linear encoder that provides position feedback, for example, by imaging a visible mark or “tick mark” associated with that transport path. Such markings can be applied, for example, via adhesive tape that marks “every micron” (or other regular distance measure) of advancement relative to a track or guide.This position feedback can optionally be used to correct the in-scan dimension advancement of the gripper (e.g., so that the gripper is inherently or transparently correctly positioned relative to the in-scan direction). In systems where such position feedback is applied to each transport path (e.g., as similar linear encoding systems are also used for printhead in-scan positioning), transducer-based correction techniques can provide offsets orthogonal to the transport direction for each printhead and gripper to define a coordinate reference system and precisely control drop placement. These techniques, by themselves, do not necessarily inherently correct non-orthogonality between transport axes (e.g., the x and y axes associated with the gripper and printhead transport system, respectively). In some embodiments, therefore, additional techniques described herein can optionally be applied to correct the positioning of the light beam used to mark the desired transport path or to otherwise control an error correction system to account for the non-orthogonality. When combined with optional techniques for fine adjustment and / or correction, these techniques help provide precise position control of all elements in a manufacturing system. These various advantages and synergies of these various techniques will be detailed below.

[0048] Considering the principles discussed thus far, light sources and detectors (depending on the implementation) and any associated optics can be used to induce and / or sense positional deviations of the transported components. At least one transducer can be used to correct transport path errors using both common-mode and differential-mode control, i.e., using feedback, by displacing what is being transported in a dimension orthogonal to the direction of transport in response to detected deviations. In still more detailed embodiments, this type of control can be applied to the “y”-axis motion of a first transport system and the “x”-axis motion of a second transport system, for example, to correct transport path errors in two different transport paths using separate sets of transducers. Correcting the two different transport paths in this way helps facilitate precise correction across deposition and / or processing parameters. For example, in the context of the split-axis printing system introduced above, correction of both the gripper / substrate path and the printhead path effectively normalizes the “print grid” (the coordinate reference system used to define where droplets will be printed), providing a system in which the system’s understanding of the print grid coordinates is precisely correct and not undermined by errors in the mechanical system associated with transport. These techniques and the various combinations and permutations discussed herein (including documents incorporated by reference) help provide precise positional control over deposited droplets. For example, these techniques can be further applied to “z-axis” (e.g., elevation) or other dimensional motion control. Alternatively, the techniques described herein can be combined with the use of per-nozzle droplet and / or nozzle parameters to provide highly accurate control over deposited liquid volume, as described, for example, in U.S. Pat. No. 9,352,561 and U.S. Publication No. 20150298153.

[0049] This disclosure will be broadly organized as follows: (1) Figures 1-3E will be used to provide an introduction to depositing material onto a substrate, sources of micro-alignment errors, and associated remedies. (2) Figures 4A-5 will be used to introduce more specific techniques, i.e., online and offline processes, related to measuring / detecting and combating errors within the considered split-axis printing environment. (3) Figures 6A-6E will be used to explain specific mechanical structures in one or more detailed embodiments. (4) Figures 7A-H will be used to discuss various use cases and optional extensions. (5) Figures 8A and 8B will be used to discuss multi-dimensional control of transport system components (e.g., x- and z-axis control).

[0050] Before proceeding with the introduction, it may be useful to first introduce certain terms that will be used herein.

[0051] A specifically contemplated implementation may include an apparatus comprising instructions stored on a non-transitory machine-readable medium. Such instruction logic may be written or designed in a manner having a structure (architectural features) to cause one or more general-purpose machines (e.g., processors, computers, or other machines) to behave as special-purpose machines, each having a structure that necessarily performs the tasks described on input operands, depending on the instructions, which, when ultimately executed, take specific actions or otherwise produce specific outputs. A "non-transitory" machine-readable or processor-accessible "medium" or "storage device" as used herein refers to any tangible (i.e., physical) storage medium from which instructions can subsequently be read by a machine, regardless of the technology used to store data on that medium, including, for example, but not limited to, random access memory, hard disk memory, optical memory, floppy disks, CDs, solid-state drives (SSDs), server storage, volatile memory, non-volatile memory, and other tangible mechanisms. The medium or storage device can be in a stand-alone form (e.g., a program disk or solid-state device) or can be embodied as part of a larger organization, such as a laptop computer, handheld device, server, network, printer, or other set of one or more devices. The instructions can be implemented in different forms, for example, as metadata that is effective to invoke an action when invoked, as Java code or script, as code written in a specific programming language (e.g., as C++ code), as a processor-specific instruction set, or in some other form. The instructions can also be executed by the same processor or different processors or processor cores, depending on the embodiment. Throughout this disclosure, various processes will be described, any of which can be implemented as instructions stored on generally non-transitory machine-readable media and any of which can be used to fabricate a product.Depending on the product design, such products can be processed to be in a sealable form or as a preliminary step for other printing, curing, manufacturing, or other processing steps that will ultimately create a finished product for sale, distribution, export, or import, incorporating the engineered layer. Also, depending on the implementation, the instructions can be executed by a single computer or, in other cases, stored and / or executed on a distributed basis, e.g., using one or more servers, web clients, or application-specific devices. Each of the functions described with reference to the various figures herein can be implemented as part of a composite program or as stand-alone modules, both stored on a single media representation (e.g., a single floppy disk) or on multiple separate storage devices. The same applies to the error correction information generated according to the processes described herein; i.e., templates representing position errors as a function of transport path position can be stored on a non-transitory machine-readable medium for temporary or permanent use, either on the same machine or for use on one or more other machines. For example, such data can be generated using a first machine and then stored for transfer to a printer or manufacturing device, e.g., for downloading via the Internet (or another network), or for manual transport (e.g., via a transport medium such as a DVD or SSD) for use on another machine. A “raster” or “scan path” as used herein refers to the progression of printhead or camera motion relative to the substrate; i.e., it need not be linear or continuous in all embodiments. The terms “hardening,” “solidifying,” “processing,” and / or “rendering” a layer refer to a process applied to deposited ink to transform it from a fluid form into the permanent structure of what is being created. These terms are relative terms; for example, the term “hardened” does not necessarily require the finished layer to be objectively “hard,” as long as the finished form is “harder” than the liquid ink deposited by the printer.The term "permanent," as in "permanent layer," refers to something intended for indefinite use (e.g., in contrast to a manufacturing mask layer that is typically removed as part of the manufacturing process). Throughout this disclosure, various processes are described, any of which can generally be implemented as instruction logic (e.g., as instructions stored on a non-transitory machine-readable medium or other software logic), as hardware logic, or a combination of these, depending on the embodiment or specific design. A "module," as used herein, refers to a structure dedicated to a specific function; for example, a "first module" performing a first specific function and a "second module" performing a second specific function refer to mutually exclusive sets of code when used in the context of instructions (e.g., computer code). When used in the context of a mechanical or electromechanical structure (e.g., a "cryptographic module"), the term "module" refers to a dedicated set of components, which may include hardware and / or software. In all cases, the term "module" is used to refer to a specific structure for performing a function or operation that would be understood by one of ordinary skill in the art to which the subject matter pertains, not as a general placeholder or "means" or "any structure whatsoever" (e.g., a "team of bulls") to perform a described function, but as a conventional structure used in a specific technical field (e.g., a software module or a hardware module). "Electronic," when used to refer to a method of communication, can also include audible, optical, or other communication functions; for example, in one embodiment, electronic transmission can encompass optical transmission of information (e.g., via an imaged 2D barcode) that is digitized by a camera or sensor array, converted to an electronic digital signal, and then exchanged electronically. The terms "transducer" and / or "actuator" are generally used synonymously and regardless of the form or type of transducer or actuator. For example, a "voice coil" and a "piezoelectric transducer" are each examples of an actuator / transducer.

[0052] Also, reference is made herein to detection mechanisms and alignment marks or fiducials recognized on each substrate, or as part of the printer platen or transport path, or as part of the print head. In many embodiments, the detection mechanism is an optical detection mechanism that uses a sensor array (e.g., a camera) to detect recognizable shapes or patterns on the substrate (and / or on physical structures within the printer). Other embodiments do not rely on a sensor array; for example, a line sensor can be used to sense fiducials as the substrate is loaded into or advanced through the printer. Note that some embodiments rely on dedicated patterns (e.g., special alignment marks), while other embodiments rely on recognizable optical features (including the geometry of any pre-deposited layers on the substrate or physical features in the printer or print head), each of which is a “fiducial.” In addition to using visible light, when referring generally to “light,” “optical system,” or “optics,” alternative embodiments can rely on ultraviolet or other non-visible light, magnetic, radio frequency, or other forms of electromagnetic radiation. Also, while it should be noted that some embodiments herein will be discussed with reference to a printhead, multiple printheads, or a printhead assembly, it should be understood that the printing systems described herein generally can be used with one or more printheads. In one contemplated application, for example, an industrial printer features three printhead assemblies, each assembly having three separate printheads with a mechanical mounting system that allows positional and / or rotational adjustment so that the constituent printheads (e.g., of the printhead assembly) and / or printhead assemblies can be individually precisely aligned to a desired grid system. Various other terms will be defined below or used as is clear from the context.

[0053] I. Introduction 1, 2A-2B, and 3A-3E are used to introduce some of the techniques discussed in this disclosure and some of the problems that these techniques address.

[0054] More specifically, FIG. 1 depicts a prior art process 101 associated with a certain type of transport mechanism. In this specific example, it is assumed that there is a substrate 103 to be printed with droplets deposited at selected nodes of a printing grid 105. The printing grid 105 is illustrated as being centered within the substrate to represent its intended position, where droplets of ink from the printhead are intended to land in precise locations (i.e., at locations represented by the nodes of the printing grid) with predictability that translates to layer uniformity. However, it should be noted that while illustrated in this manner, the printing grid is defined relative to the printer (and not specifically the substrate) and extends to any location where printing can occur (e.g., the printable area may be larger than the substrate, and errors in substrate position could potentially translate to errors in droplet landing locations). Also, it is assumed that the spacing between vertical and horizontal lines is generally predictably spaced; however, this is typically based on the assumption that advancement along the x and y transport paths is precisely accurate (and / or linear). Finally, and while a printer, substrate, and printed grid are illustrated herein, it should be noted that these problems are not specific to printers, and the techniques described herein can be applied to a wide variety of situations in which something is mechanically transported, rotated, or moved. The context of a printing process, substrate, and printed grid is used as a non-limiting illustrative example to introduce the problems and techniques described in this disclosure.

[0055] Printing occurs as the substrate is transported, generally as represented by arrow 104, and a transport system mechanism is assumed to guide the substrate along transport path 107. This transport path is illustrated in FIG. 1 as being slightly curved, which in this example represents a mechanical imperfection in the transport system (e.g., of some type of edge guide, track or traveler, or other means used to steer substrate 103). Note that in a typical industrial printing process, such as for making OLED display panels as described above, the substrate may be approximately 2 meters by 3 meters in size, while the nonlinearity of path 107 may be a few microns or even smaller. The curvature (or other error) of path 107 as depicted in FIG. 1 is therefore exaggerated for purposes of discussion and illustration. While errors of this magnitude are inconsequential in many applications, in certain manufacturing processes (e.g., manufacturing OLED displays and / or certain other electronic devices on large substrates), errors of this type may limit achievable product size, lifetime, or quality. That is, the droplets generally need to be deposited at precise locations so that they mix together and produce a homogeneous layer without leaving gaps or pinholes. Upon landing, droplets spread only to a limited extent, and surface irregularities in the finished layer can limit the achievable layer thinness and otherwise create quality issues. Even slight mislocation of droplet landing sites can affect product quality and / or manufacturing reliability.

[0056] As a diagram, FIG. 1 is conceptually divided into two halves, including a left half and a right half. The left half of the diagram shows a substrate 103 and a slightly curved transport path 107. The substrate 103 is generally advanced back and forth along this path 107 in what is designated the “y” dimension, as referenced by arrow 104. Number 103 represents the substrate at some point in proper alignment with a printing grid 105. The printing grid as depicted in this diagram is an abstraction in which the vertical lines represent the apparent paths of individual nozzles in a printhead as the printhead and substrate are moved relative to one another, while the horizontal lines represent digital firing signals or other capabilities of the nozzles to refill and fire repeated drops of ink (i.e., the spacing between these horizontal lines typically represents the “speed” at which a nozzle can fire). Alternatively, described differently, the printing grid 105 has nodes, each of which represents an opportunity to fire a drop of ink. As already indicated, it is desirable to deposit ink in a positionally precisely controlled, pinhole-free manner, achieved in part by having precise knowledge of where each droplet will land on the substrate. Furthermore, it should be noted that while the droplets are deposited at discrete locations, they are viscous and therefore typically spread out to form a continuous liquid coat without gaps or irregularities. The volume per unit area is generally pre-correlated with the desired thickness or other properties of the final layer; therefore, droplet density and relative position can theoretically be selected (taking into account expected droplet size) in a manner that promotes a desired effect, e.g., a uniform layer of a desired thickness after droplet spreading and mixing (this is discussed in U.S. Pat. No. 8,995,022, incorporated by reference).

[0057] The printing grid 105 is depicted diagrammatically in the left half of the figure in a "squared up" fashion with the substrate 103 representing where printing will generally occur at the desired drop landing locations.

[0058] Unfortunately, errors (i.e., curvature) in the transport path 107 can effectively distort the printing grid 105, meaning that droplets do not necessarily land where they are supposed to be relative to the substrate, as they are subject to minute positional and rotational errors as the substrate is advanced. The right hand side of Figure 1 shows the substrate translation and / or orientation errors as the substrate is advanced from a first position d0 along the transport path 107, with the substrate position and yaw represented by 103' relative to a (virtual) ideal "reference edge" 109, and the substrate position and yaw represented by 103" relative to the reference edge 109, to a second position d1 along the transport path. As can be seen, the substrate is subject to offset and rotational errors in multiple dimensions due to errors (e.g. curvature) in the transport path 107. The errors can be seen in this example to be horizontal and vertical offsets Δx0 and Δy0, and an angular offset Δθ0 in the xy plane when the substrate is moved to the first position d0, and different horizontal and vertical offsets Δx1 and Δy1, and an angular offset Δθ1 when the substrate is advanced to the second transport path position d1. As the nature of these errors changes as the substrate is advanced, these errors may be measured in a number of dimensions. The effect of the described type of error is to distort the print grid. For example, while the system and printing plan may effectively assume a linear print grid (105 in FIG. 1), "y" error and / or jitter (i.e., parallel to the transport path) effectively distorts the separation between the horizontal lines of that print grid. Similarly, "x" dimension error and / or jitter effectively distorts the separation between the vertical lines of that print grid, resulting in errors in the deposition location of individual droplets.These types of errors can result in too little or too much fluid deposition or other non-uniformities in various pixel wells, potentially leading to brightness and / or hue variations or other errors in the finished display; in the context of "macroscopic layers," such as encapsulation errors across many electronic components, these types of errors can lead to non-uniformities in the layer, potentially impairing layer function.

[0059] As illustrated in this example, it should be noted that the depicted errors may, in some cases, simply be a repeatable function of the transport path 107, i.e., because the transport path is considered curved in this example, there is a nonlinear displacement in the x-dimension, a nonlinear displacement in the y-dimension, and a nonlinear slope. Other types of errors, such as z-dimension error, pitch, and roll, may also potentially occur on a repeatable basis but are not depicted in this particular diagram. Thus, in applications such as industrial printers used to create fine (e.g., micron or smaller scale) electronic, optical, or other structures that rely on uniformity of the type described, the same errors could potentially occur from substrate to substrate if a series of substrates are to be printed as part of an “assembly line” type fabrication process. There are also other potential sources of error that may be specific to a given substrate and / or may represent changing conditions, e.g., temperature fluctuations.

[0060] While errors affecting substrate advancement are illustrated, there are other sources of analogous errors that can potentially affect device quality and / or process reliability. For example, split-axis printers typically move not only the substrate but also the printheads or cameras or other mechanical components. Briefly, in systems that move one or more printheads (generally in the “x” dimension relative to FIG. 1 ), analogous path errors can result in “x,” “y” rotations or other errors in the printheads (relative to the dimensions of FIG. 1 ). For example, if the printheads have errors in different positions, such errors also typically have the effect of distorting the vertical lines of the printing grid 105 (i.e., spacing them unevenly). Similar analogies can be drawn with respect to other transport path analogies in industrial printing systems of the referenced type. In general, it is desirable to reduce the effects of these layers, improve predictability and reliability in layer processing, and generally have the ability to process thinner, more uniform layers.

[0061] To address these issues, one embodiment provides a transport path correction system that detects and neutralizes one or more forms of path error. FIG. 2A shows an embodiment 201 having two main components, including a first track-guided component 203 and a second offsettable component 205. Both of these components generally move together in the general direction represented by arrow 206. In one implementation, these two components can be part of a vacuum gripper used to engage and move a substrate along a "fast" axis. In another implementation, these two components can instead be part of, for example, a printhead traveler that travels a track and carries a printhead for use in printing droplets on a substrate.

[0062] The depicted embodiment uses a light source 207 that directs a beam of light 202 in a manner that will serve to guide or promote the desired travel—in this case, a perfectly straight line of travel that simulates a “virtual edge guide.” In the depicted approach, the light source 207 is stationary, and the beam 202 it emits is sensed by two optical detectors 208 and 209, both mounted on a second component. Additionally, beam splitters 211 and 212 are used to redirect light from the optical path to detectors 208 / 209 in a manner that will be used to sense and correct deviations of the second component from the optical path. Note that the depicted structure is not required for all embodiments; for example, a specifically contemplated variation features a light source mounted on a second component with one or more beam splitters and / or one or more detectors stationary; other configurations are possible and will occur to those skilled in the art.

[0063] To correct for path deviations, signals from each of the detectors are optionally fed to processing circuitry 214 / 215, which applies a function "F" to these signals to generate correction signals that will be applied as feedback to correct the path deviation. While two sets of such circuits are depicted, it is possible to use only one circuit (e.g., a software-driven processor) or have significant duplication of circuit elements. The correction signals are then fed to one or more transducers "T," which immediately apply a correction to "null" any deviations from the optical path; i.e., advantageously, the processing circuitry and / or detectors generate signals that are "zero" (or do not cause further transducer adjustments) when the second component 205 is synchronized with the optical path, and that always drive the second component 205 back to zero when there is a deviation from the optical path. Note that this structure is not required for all embodiments. In the figure, it can be seen that the depicted embodiment relies on two transducers, specifically numbered 216 and 217, each providing a substantially linear throw in a direction orthogonal to the direction of transport. In this example, the use of two transducers at distinct interaction points (c1 / c2) between components 203 and 205 provides common-mode and differential-mode control, respectively, to linearly offset component 205 from the first component 203 (in the direction of arrow 213) and to provide rotation of component 205 relative to component 203 as represented by angular measure "θ." The transducers can be any desired type of transducer suitable for the throw in question, including, but not limited to, piezoelectric transducers. In embodiments in which the substrate is supported by an air bearing (and component 205 engages the substrate using a vacuum gripper), the transducer can advantageously be a voice coil, providing a relatively large maximum throw (e.g., submicron to 100 microns or more) with a high degree of repeatability and reliability.The combination of common-mode and differential-mode control for the transducer essentially provides a floating pivot point between components 203 and 205 that can be offset in the “x” direction (note that the x, y, and z coordinate labels seen in the figure are arbitrary in this example). To help provide mechanical structural support between components 203 and 205, in some embodiments, a mechanical linkage (“M”) 218 ​​can be used that constrains components 203 and 205 to move with each other in the “y” direction while simultaneously allowing free offset and relative x, y rotation between these components in the “x” direction. Such additional structural linkage can be particularly advantageous when a voice coil is used as the transducer, to help constrain any unwanted load on the transducer in a direction orthogonal to the direction of transducer displacement. Numeral 221 provides additional details regarding the detector and indicates a two-cell design, with cells represented by values ​​“a” and “b.” Briefly, in one design, light from a light source impinges on one or both of these sensors, and the difference between the voltages generated by each of these sensors is used to linearize the second component 205 relative to the optical path. For example, in a two-cell design, the value "(a-b) / (a+b)" generates positive and negative outputs proportional to the amount of deviation from the midpoint of the two cells. Such a signal can be used alone to drive a transducer associated with the position where the optical path is centered between the two cells. Note that in some embodiments, the processing circuitry 214 / 215 can be combined with the detector and purchased as a single unit, providing, for example, a digital or analog output representing the imbalance signal sensed by each cell of the detector.

[0064] In some embodiments, it is possible to sense path deviation in more than one dimension, for example, in each of the x and z dimensions relative to the depicted coordinate system. For this detection of deviation, a four-cell design, represented by numeral 223 in the figure, can be used. For example, the value "[(a+c)-(b+d)] / (a+b+c+d)]" can be used to sense x-dimension deviation from the desired path, and the value [(a+b)-(c+d)] / (a+b+c+d)] can be used to sense z-dimension deviation from the desired path. Note that to correct deviation motion in the second (or third, fourth, etc.) degree of freedom, a separate second set of correction transducers (not seen in this figure) may be required, depending on the implementation. The transducer configuration is similar to that already depicted in FIG. 2A, except that the direction of transducer displacement can be, for example, along the z dimension. It should be noted that the use of a linear transformer is not required for all embodiments; conversely, corrections can be made with respect to one or more rotational degrees of freedom, for example, to equalize surfaces or edges and to correct for pitch, yaw, and / or roll.

[0065] FIG. 2A also illustrates several additional optional components that may be used in some embodiments. First, numeral 225 refers to an adjustment mechanism that can be used to align and / or adjust light source 207. In one embodiment, the light source is a laser, and numeral 225 refers to a screw-based precision mount that changes the attitude and / or yaw of the laser relative to the direction of transport. Second, numerals 227 / 229 refer to beam splitters and detectors that can be used for the same purpose; for example, by mounting such detectors in a fixed manner relative to light source 207, the light source can be periodically recalibrated (e.g., adjusted using adjustment mechanism 225) to ensure proper orientation. It is also possible to use a reference 231 at the far end of the optical path to aid in alignment and / or automatically provide feedback regarding the proper orientation of the light source. In one embodiment, the reference can be a simple target or line of sight (e.g., the laser is adjusted until its beam strikes the center), while in another embodiment, the reference can be a detector / circuit that provides electronic feedback, for example, allowing for manual or automatic alignment of the light source.

[0066] FIG. 2B is a flowchart depicting method steps 251 that implement some of the techniques introduced above. As represented by numeral 252, the method can be embodied in a manufacturing system having a transport path where it is desired to correct for fine motion, position, or orientation errors in the transport system. For example, the manufacturing system can implement high-precision product “assembly line” manufacturing, as introduced above, using a printer for material deposition. Initially, an alignment or calibration step 253 can be performed to ensure that the light beam is accurately directed as desired to mark a linear progression. For example, as introduced above, the light beam can be used to image a stationary target using a line of sight, and adjusted 254 either manually by a human operator or automatically based on electronic feedback until the light beam is incident with the reticle formed by the line of sight. In a typical implementation, calibration can be performed upon initial installation, at start-up, periodically (e.g., daily or weekly), upon the occurrence of a milestone event (e.g., a detected error above a threshold or a temperature change above a threshold amount), or as otherwise desired. A series of substrates 255 are then introduced in succession and aligned with the printer's coordinate reference system to ensure that the individual panel products on these substrates are in known positions relative to the light beam (e.g., as formed by a properly aligned laser). This process will be discussed further below, but in one embodiment, the combination of optical alignment marks per transport path (e.g., position feedback for the gripper and printhead) and two transducer-based error offset systems and associated optical paths effectively define a coordinate reference system for the printer and coordinate motion in that coordinate reference system. Each given substrate in the series can be individually aligned to this coordinate reference system by imaging fiducials on the given substrate and adjusting either the substrate position / orientation or the printing recipe so that printing occurs precisely on each panel as desired. Printing then occurs on the aligned substrate.As each conveyance or transport system is operated, the error (i.e., deviation from each marked optical path) is dynamically measured by numeral 255, optionally for more than one transport path and / or one dimension per transport path, as indicated by numeral 257, and optionally using one error correction system to correct for multidimensional error (e.g., x and z deviation using a four-cell detector design), by numeral 258. Dynamic correction 259 is then applied as feedback to instantly correct the error and to change the position and orientation of the "second component" relative to the first component to drive the deviation from the associated optical path to zero, i.e., so that the "thing" being transported (e.g., substrate, camera, print head, or other element) travels the desired perfectly straight path despite microscopic jitter that may still affect the transport system. As mentioned above, in one embodiment, alignment along the direction of transport (e.g., in a direction parallel to the light beam used as a guide) can be optionally assisted through the use of an alignment system, for example, measuring marks on adhesive tape proximate to the transport path, with alignment marks every 1 micron of progression along the transport path. A transducer-based correction system in such an embodiment is therefore relied upon to correct path and rotational deviations in a direction perpendicular to the marked optical path direction (e.g., optionally using two or more transducers per numeral 265 and differential mode control for two or more transducers per numeral 267). The result is that what is being transported follows a hypothetical ideal path as already referenced and identified by numeral 269.

[0067] Having introduced transducer-based correction and the use of optical guidance, its application to path error control will now be discussed, again in the exemplary context of an industrial split-axis printer environment.

[0068] FIG. 3A shows an embodiment 301 for reducing transport path error in a gripper system advancing a substrate, such as substrate 103 from FIG. 1 . More specifically, it is again assumed that the substrate is advanced back and forth along the path represented by arrow 104. In this example, the substrate would be advanced using a gripper. A first component 302 of the gripper would generally travel along path 107 (from FIG. 1 ) along a track extending in the “y” dimension. The gripper also has two transducers (T) 305 and 306 that operably connect the first component 302 with a second component 303 that engages the edge of the substrate. In one exemplary case, the substrate is supported on air bearings above a floating table to provide nearly frictionless support, although in other examples, other mechanisms can be used for support and transport. Each of the two transducers is controlled to displace the second component relative to the first component along a common direction (e.g., in the “x” dimension as illustrated in the figure), as represented by arrow 310. Each transducer can be controlled independently, leading to a situation where “common mode” control linearly offsets the second component in the x dimension toward and away from the first component 302 at a respective engagement point, while “differential mode” control pivots the second component relative to the first component about pivot point “Xpvt.” Because the transducers can be electronically driven in a manner having both common and differential drive components, it can be seen that pivot point “Xpvt” is a floating pivot point. In some embodiments, this floating pivot point can be an abstract concept, while in other embodiments, a mechanical structure provides the pivot while also providing a structural connection between the two components of the gripper. It should be noted that although this figure shows the gripper as engaging the substrate near its upper left corner, in typical circumstances it may be desirable for the gripper to engage the substrate midway along its length, for example, to provide a relative moment of the transducers (e.g., to facilitate control over both common mode and differential mode displacements).

[0069] While the first component 302 follows the error-disturbed path 107 from Figure 1, the second component latches onto what is being transported (in this case, substrate 103, e.g., using a vacuum) and is dynamically offset to follow a linear path. Transducers 305 and 306 are seen to be independently controllable to move the substrate, as indicated by arrows 308 and 309, and are controlled in a manner to precisely nullify x-dimensional and θ-rotation-induced errors within path 107 so that the substrate motion follows an ideal "reference edge" (see line 109 from Figure 1). Note that in an alternative design, instead of having linear throws that are parallel to each other, transducer 305 could achieve rotation while transducer 306 could achieve a linear throw, or the transducers could be made to create an offset in the "y" dimension or any other desired dimension, with the corresponding effect of mitigating errors in the substrate's position or rotation. 3A, the gripper's first component 302 moves along the "y" dimension, while transducers 305 and 306 each push and pull the substrate along a linear range of motion along the "x" dimension via contact at respective contact points "c." Again, each transducer, in this example, can be a linear motor, piezoelectric transducer, voice coil, or another type of transducer.

[0070] In this example split-axis printing system, the substrate is advanced in the "y" dimension relative to the printhead for a particular "scan" or raster motion. The "y" dimension in this example therefore also forms the "in-scan" dimension. The printhead is then moved in the "x" dimension (i.e., in the "cross-scan" dimension) to reposition the printhead for the subsequent scan, and the substrate is then advanced in the opposite direction for the subsequent scan, with successive scans continuing until the entire liquid coat is created. The substrate can then be advanced (typically out of the printer to another chamber) and the liquid coat cured, dried, or otherwise processed to transform the liquid coat into a permanent structure with desired electrical, optical, and / or mechanical properties. The printing system is then ready to accept another substrate and perform similar printing on the subsequent substrate, for example, according to a general predetermined "recipe."

[0071] It has already been mentioned that errors along the transport path 107 (from FIG. 1 ) can potentially lead to errors in multiple dimensions (i.e., not just an offset in the x dimension). This may be less significant if the transport system is positionally adjusted (e.g., using registration marks as already referenced), but in other systems, angular variations in the path may also lead to nonlinearities in the y position of the substrate. In such implementations, y-dimension errors can optionally be corrected using other forms of means 311 for correcting substrate motion in the “in-scan” dimension. Options include, for example, using a third transducer 314 to achieve a throw of the first and / or second components of the gripper in the in-scan dimension to normalize the y-dimension advancement of the substrate. In other embodiments, feedback can instead be used to adjust the electronic control signal 315 (e.g., as a feedback signal, delta signal, or electronic drive signal) for gripper advancement to impart a slight velocity increase or decrease (Δv) to counteract y-dimension errors, or gripper movement can be triggered to align position markers as introduced above. In yet another optional embodiment, adjustments can also be implemented in software, for example, calculating and programming individual y-position-dependent nozzle firing delays (as represented by box 316); i.e., the nozzles of the print head can be “commanded” to print slightly earlier or later as the substrate and print head are moved relative to each other in the “y” dimension in a manner that, in some embodiments, accurately counteracts “y”-dimension position errors of the substrate relative to the printer. Also, per numeral 317, in another embodiment, the “trigger” signal used to time nozzle firing can be adjusted to have the effect of shifting the horizontal lines of the printing grid (see numeral 105 from FIG. 1 ) to counteract position errors of the substrate relative to the printer. Note that gripper "in-scan" or "y-axis" compensation is not required for all embodiments.

[0072] FIG. 3A also shows the optical system used to define the desired travel. As already mentioned, a light beam 318 is directed from a light source 319 (e.g., a laser) in the direction of travel (e.g., parallel to the y-dimension as referenced in the figure). At least one sensor or detector 320 is used to image this path and detect deviations from the light beam 318 as the gripper and substrate move along their transport path. Advantageously, the at least one sensor or detector 320 is mounted in a fixed manner on the second component 303 of the gripper so that, as travel occurs, feedback signals derived from the sensor or detector 320 are used to reorient and displace the substrate in the x-dimension and xy orientation so that the substrate movement accurately corresponds to the marked optical path (318), even though the movement of the first component of the gripper continues to be subject to mechanical jitter. As mentioned above, in contemplated variations, the light source 319 and sensor / detector 320 can be configured differently, for example, with the light source 319 mounted on the second component 303 of the gripper, using beam splitter optics mounted on the gripper, etc. Such design variations are well within the skill of one skilled in the art of optics.

[0073] 3A, it should be observed that the use of two or more transducers in a mechanical transport system can correct for transport path errors or other motion errors (e.g., with respect to nonlinear guides or tracks or edges). While path errors may exist, as represented by numeral 107 in FIG. 1, the techniques and structures introduced above attempt to "coexist" with this reproducible transport path error (e.g., the gripper's first component 302 continues to travel a path disturbed by this error), but the transducers achieve a throw or other correction to equalize and / or neutralize this path error in at least one dimension, so that what is being moved (in this example, the substrate) travels an idealized path, as represented by numeral 109 in FIG. 1. In one embodiment, these motion corrections can be achieved mechanically by two or more transducers (e.g., transducers 305 and 306, each independently controllable with a linear throw in a direction (e.g., 310) substantially orthogonal to the direction of arrow 104) that are parallel to each other and each have a linear throw substantially orthogonal to the direction of conveyance.

[0074] While these techniques can be applied to virtually any mechanical transport system, one area that could benefit from these techniques has already been described as involving industrial printers, where ink droplets need to be deposited at very precise locations. For example, one contemplated embodiment is as a printer used to fabricate light-emitting devices such as organic LED display devices (e.g., cell phone screens, HDTV screens, and other types of displays) and “panel” devices such as solar panels. In this regard, in the applications discussed above (e.g., on which meter-wide and long substrates are printed), some conventional systems rely on air-floating tables to advance the substrate during printing. Gas ingress and egress in such systems can be carefully controlled to avoid imparting effects to the substrate (e.g., temperature, static buildup, or other effects that could affect ink behavior) that could potentially cause defects in the finished layer. In other words, gas flow is used to generate a fluid bearing beneath the substrate, creating a substantially frictionless surface along which the substrate moves during printing. In such applications, the second component 303 from FIG. 3A can support a vacuum chuck that engages the substrate, or multiple vacuum locks that engage individual components of the substrate. In such applications, to achieve the “micron-scale” (or smaller) throw used to neutralize nonlinearities and provide precise path advancement, transducers 305 and 306 can advantageously be formed as voice coils that use compression and expansion (i.e., normal to the direction of the force supported by the floating table’s gas bearings) to achieve the microscopic throw used to achieve precise printhead and nozzle alignment with the substrate. That is, with respect to electronic flat panel processing specifically, and with respect to OLED display device processing specifically, the use of (frictionless) floating supports and vacuum grippers is important to minimize defects and maximize device lifetime, and the use of voice coils as transducers has been found to provide an effective component for providing the required throw in such systems.However, other types of transducers can also be used to achieve the throw for a particular type of application, for example through the use of a piezoelectric transducer, a linear motor, or other type of transducer. In such systems, a floating mechanical pivot mechanism can optionally be used to assist the voice coil in providing structural linkage and mechanical support for error correction.

[0075] FIG. 3B provides a diagram 321 similar to that of FIG. 1, but further illustrates a goal achievable using the mechanism of FIG. 3A. More specifically, FIG. 3B shows the substrate 103 and gripper from FIG. 3A as they advance along path 107. As in FIG. 1, path 107 is again assumed to have errors that exhibit some form of curvature or variation; again, this may be errors in edge guides, tracks, or other mechanisms, and this error imparts position and / or rotational errors to the gripper. However, in this case, the gripper is viewed as having a transducer “T” that is controlled to counteract this error, for example, in the form of a voice coil displacement that compensates for or equalizes the variation in path 107. Again, it should be noted that the magnitude of the error is greatly exaggerated relative to the scale of FIG. 3B; for example, in practice, the path may be meter-long (e.g., a 3-meter-long substrate transported through a room-sized printer), while the curvature may be micron or sub-micron in scale.

[0076] It will be recalled from FIG. 1 that at gripper position d along the path, the original transport path error was equal to Δx, Δy, and Δθ. However, with respect to the system of FIG. 3B, the transducers are actuated to displace and / or rotate the substrate as seen on the lower right side of FIG. 3B and designated by numeral 103′. That is, transducer “T” displaces the gripper second component and substrate relative to the gripper first component and track or edge guide 107 to have absolute positions x, y, and θ. In the context of 3B, the quantity x represents an absolute x position that effectively defines a virtual edge 323 offset from the error-disturbed transport path 107, the quantity y corresponds to an optional positioning offset of the substrate that offsets it to an arbitrary “smoothed” or normalized advance (330) relative to the in-scan (or transport) direction, and the quantity θ corresponds to the desired angular orientation of the substrate. For the example of FIG. 3B , it can be assumed for the moment that y and θ are “zero,” e.g., the substrate is oriented to be exactly vertical (i.e., squared off relative to the floating support table with no “y” dimension correction, although this need not be the case in all embodiments). In FIG. 3B , the printing grating is depicted at 105′ to have a consistent x and θ relationship to the substrate 103′. As the substrate is advanced from position d to position d, the transducers are controlled to maintain this consistent positional relationship between the substrate and the normal of the printing grating, i.e., the substrate is aligned to have absolute positions x and θ (despite errors along path 107) and is therefore depicted at 103″ as having exactly this relationship to the printing grating at 105″. It should be noted that in these examples the printing grid is illustrated as maintaining a predetermined relationship to the substrate, however the printing grid is defined by the print head positioning and substrate and print head transport system, and what is truly desired is for the print head and substrate transport mechanisms to maintain a consistent predetermined relationship to each other, and for the coordinate system established by this linkage to be precisely aligned for each product being processed.In some embodiments, the printer coordinate reference system is first calibrated (and adjusted) to effectively define the printing grid, and each substrate (or product being processed thereon) is then specifically aligned to the printing grid as it is introduced (i.e., into the printer) via a product-by-product or substrate-by-substrate alignment process, as will be further illustrated below.

[0077] Equations are depicted at various locations in the figure to show how constant positional relationships are maintained. More specifically, it will be recalled that the inherent repeatable error of transport path 107 at position d was equal to the position and rotation offsets of Δx, Δy, and Δθ. Converter "T" is therefore controlled to add additional offsets of Δx, Δy, and Δθ, which are applied in response to detected errors at position d along the transport path. That is, in one embodiment, these values ​​are the negatives of the errors Δx, Δy, and Δθ, i.e., they exactly cancel the errors, optionally offsetting the substrate to some predetermined x / y / θ value. In one embodiment, the depicted converter "T" corrects only the substrate position in x and θ (e.g., any "y" dimension correction is optionally achieved using a position feedback / adjustment system as described above). Note how at position d1, the converters are controlled to add different offsets, i.e., Δx4, Δy4, and Δθ4, depending on different errors in position on transport path 107. As depicted in FIG. 3B, the values ​​x5 and θ5 can be exactly equal to the values ​​x3 and θ3, although again, this need not be the case in all embodiments.

[0078] Micron-scale or better position control is in many ways not as intuitive as it may seem. For example, in one embodiment, the gripper transport system and the printhead transport system each carry a camera that is used to find a common registration mark, thereby establishing the origin of a coordinate system that matches the two transport paths. This process, and the transport systems for each printhead and substrate in such a system, effectively define the printer's coordinate reference system (and in large part determine the configuration of the printing grid according to which droplets can be deposited). U.S. Provisional Patent Application No. 62 / 459,402, previously incorporated by reference, provides information regarding the use of these cameras, position detection, and associated calibration. Essentially, in one disclosed system, in addition to finding a common coordinate point (or "origin"), each transport system uses optical tape and optical sensors to provide precise (e.g., micron-scale) position detection and feedback so that the transport system (e.g., the gripper's first component) "knows" exactly where it is relative to the printer's coordinate system, and these various components work together to effectively define the complete printer coordinate system. In fact, the use of such a system can eliminate the need for component offsets in the direction of transport; for example, a gripper is simply driven to a specific, appropriate position value in the direction of transport.

[0079] Once the "origin" is established by the referenced camera alignment process, the two transport systems are coordinated to determine the relative coordinates between each transport system's camera and a transport system reference point (e.g., corresponding to a printhead nozzle position), which then enables precise identification of any point relative to the printer's coordinate system, assuming a proper understanding of the relationship (e.g., orthogonality) between the coordinate axes. As previously mentioned, in such a system, the printer's "understanding" of drop landing locations depends on the printing grid, which is in turn defined by this coordinate system. Transport path motion errors in such a system, if left uncorrected, can potentially lead to a situation where a particular printing grid location (e.g., associated with an understanding of a specific combined gripper / printhead position) deviates from the actual positions of these components. By correcting the transport path errors in the manner described herein using the various devices described herein, this enables the system to correct the path errors so that the substrate and printhead are each positioned in a manner corresponding to the printing grid assumption. In fact, as described elsewhere herein, even errors such as minor non-orthogonality between transport paths can be corrected using optional rotational offsets (e.g., non-zero values ​​of θ3 and θ5) and / or by adjusting optical guides (e.g., light beams for one or more transport paths) to correct for non-orthogonality within the transport paths, as described above.

[0080] Continuing with the example provided by Figure 3B, each substrate introduced into the system then has one or more fiducials identified and used to precisely understand the position of the substrate (or the panel product thereon) during printing. As each substrate is introduced, its fiducials can be detected (e.g., using one or more of the cameras), and a mechanical system can be used to properly orient / align the substrate to correspond to the expected position (note that this process is not necessary for all embodiments; for example, it is also possible to adjust printer control information, i.e., by modifying the printing recipe and / or firing triggers or details, to accommodate known substrate misalignment or angular orientation loss).

[0081] The bottom portion of FIG. 3B shows how two linear transducers (e.g., voice coils) on the gripper are driven to correct for rotational errors and positionally offset the substrate in a manner corresponding to an idealized edge (e.g., via displacement in the “x” dimension). More specifically, a local portion of the transport path is designated by numeral 327 as having a significant amount of curvature that deviates from the idealized straight edge 109 of the transport path. At two effective contact points between the substrate and the transport path (designated “c1” and “c2,” respectively), this error is assumed to be “xi” (depicted as an offset relative to the idealized straight edge in the negative direction) and “xj” (depicted as an offset relative to the idealized straight edge in the positive direction), respectively. Here, it is assumed that it is desired to precisely position the left edge of the substrate (or printable area of ​​the substrate) at an absolute position “xk” from the idealized transport path (e.g., corresponding to the depicted virtual edge 323). Number 105' represents a slight offset in the printing grid to accommodate the full range of "x" positional errors imposed by the system, and optionally provide some slight buffer. To achieve this correction, a positive error (i.e., xi) at position "c1" is further offset by the amount "xk-|xi|", while a negative error (i.e., xj) at position "c2" is further offset by the amount "xk+|xj|". Two depicted transducers "T" are controlled for this purpose, thus straightening the substrate relative to an idealized straight edge. Similar corrections are performed at all other times during the movement of the gripper along the transport path 107, depending on the errors at the relevant positions, i.e., so that the substrate follows a virtual path associated with absolute position "xk".

[0082] A few points should be noted with respect to this discussion. First, while the gripper is depicted in this figure as a single unit, it may actually be comprised of many parts (e.g., the first and second components described above, or a distributed series of two, three, five, or another number of grippers or gripper components that engage the substrate at different locations). Second, while in this embodiment two transducers are depicted as parallel linear actuators (e.g., voice coil or piezoelectric transducers, respectively), this is not required for all embodiments. That is, depending on the embodiment, transducer "T" may be coupled in series and may be rotary, linear, or other types of actuators. In still other embodiments, more or fewer than two transducers may be used. Third, as noted above, various mechanisms exist for identifying the position along the transport path; for example, a signal (e.g., a drive signal, a timing signal, etc.) may be used for this purpose, as represented by numeral 328, or a position sensor 329 (e.g., a camera) may be used. In one specifically contemplated embodiment, as referenced above and discussed in U.S. Provisional Patent Application No. 62 / 459,402, a position marking system and position detectors are used for each transport path to measure and / or adjust associated positions (e.g., for print head transport and substrate transport). Clearly, many alternatives are possible.

[0083] As previously referenced, a processing apparatus or system can have multiple transport paths. In the context of a split-axis printer, in one embodiment, as previously referenced, the printer coordinate reference system can be defined based on separate printhead and substrate transport paths. FIG. 3C is used to discuss position errors resulting from inaccuracies in a second transport path, such as the printhead transport path. Such a situation is generally depicted by numeral 351 in FIG. 3C. The substrate is advanced by a gripper in a first dimension (i.e., using one transport system, as represented by arrow 104), and the printhead is advanced along a second transport path 356 in a second dimension (i.e., using another transport system, as represented by arrow 354). At a first position 353 of the printhead along the transport path associated with the latter transport system, the printhead is subject to errors Δi0, Δj0, and Δφ0. Note that the variables i, j, and φ represent x and y offsets (and angular rotations in the xy plane), but i, j, and φ are used instead of x, y, and θ to distinguish this embodiment from that of a gripper transport system. When the print head is advanced to position 353′, as represented by the phantom lines on the right side of the figure, the errors are Δi1, Δj1, and Δφ1. Again, this error is a function of position along transport path 356, and the variation in error is potentially linear or nonlinear. If left uncorrected, this error can also distort the print and cause manufacturing accuracy problems as already referenced. In this embodiment, any motion of substrate 103 relative to the gripper transport path is assumed to be corrected using the depicted gripper (and its transducer “T”), but note that the print head traveler can also generate errors, resulting in x, y, or θ errors of the print head and changing the expected landing position of droplets ejected from the print head nozzles.The effects of these errors are illustrated relative to the intended printed grid 357, as shown by arrow 355; i.e., the effect of unintended printhead rotation (and / or unintended "x" dimension displacement) is seen through a distorted printed grid 257' (in a similar manner, unintended printhead rotation displacement in the "y" dimension would effectively result in "squeezing together" the vertical printed grid lines).

[0084] In relation to the figure, it is also desired that the print head undergo ideal motion, i.e., motion that is not characterized by unintended mechanical errors. That is, in this example, it is also desired that the print head follow a virtual ideal (e.g., linear) transport path 325 that would effectively correspond to the unperturbed print grid (e.g., represented by numeral 357). This is achieved in one embodiment by having the transported object (i.e., the print head) follow both a virtual "ideal" gripper motion represented by vertical line 109 and a virtual "ideal" print head motion represented by horizontal line 325.

[0085] In much the same manner as gripper path correction, the carriage system for the print head transport path can also optionally use an optical guide (e.g., a laser source and associated optics / detection system) and a set of transducers to facilitate idealized print head positioning. To this effect, in response to dynamically sensed errors, the transducers advantageously provide a displacement to an arbitrary "absolute" position that accommodates the entire range of print head "y" position error, optionally providing some slight buffer, so that the print head motion corresponds to a virtual path 369 that also provides a fixed, known position corresponding to the "offset" printing grid (105' from FIG. 3B).

[0086] FIG. 3D provides an illustration of a system 361 intended to correct for this type of error. Specifically, FIG. 3D shows a second transport path 356 used to support lateral movement of one or more printheads in the general direction indicated by arrow 354. The printhead assembly includes a first “track-guided” component 363 that rides along transport path 356 (e.g., along a track or guide) and a second offsettable component 364 that mounts the printheads. These first and second components are again operatively coupled by one or more transducers 365. The transducers, in this example, are linear actuators that each support a microthrow to offset the second component in the “y” dimension (and / or the “z” dimension), and common-mode and differential-mode drive are again used to selectively achieve linear displacement and / or xy-plane rotation (θ). As represented by both numerals 367 and 367' (representing the printhead at distinct positions along the "cross-scan" or "x" dimension, respectively), the corrections allow the printhead to follow a virtual ideal path 369 uncharacterized by mechanical errors (i.e., even though first component 363 continues along error-impeded second transport path 356). Light source 370 is again positioned to direct light beam 371 to detect and correct jitter in a dimension orthogonal to the direction of the light beam. Note that depending on the design (and size and / or available space on the printhead assembly), it may be desirable to have the light source mounted on second component 364 and detect beam deviation relative to stationary detectors and / or optics (not shown) rather than detecting movement of the detectors and / or optics relative to a stationary beam.Similar to the gripper embodiment, the transducers of FIG. 3D can be controlled to offset the printhead to an absolute y-position (i.e., corresponding to line 369) such that when the printhead is at position 367, the aforementioned errors in Δi, Δj, and Δφ are further offset by Δi, Δj, and Δφ, and when the printhead is at position 367′, the transducers are controlled to offset the printhead and add offsets Δi, Δj, and Δφ. i and φ typically have constant values ​​at positions 367 and 367′ and are also typically both zero, although again, this is not required for all embodiments. As with the previous gripper example, the depicted transducer configuration is merely exemplary; different transducers (e.g., rotary transducers) can be used and can be applied to different transport systems and / or dimensions. Furthermore, similar to the previous example, the depicted transducers offset the printhead in this embodiment using both common-mode and differential-mode control to achieve a floating pivot point. The result is that the desired "error-free" transport path 325 is offset to an arbitrary position 369 that is sufficient to encompass any "y" or in-scan dimension jitter due to imperfections in the second transport path 356. The result of these dynamically applied corrections, as indicated by numeral 355' (and the optional use of gripper corrections as already referenced), effectively normalizes the print grid, as indicated by numeral 357". Note that it is also possible to offset the position of part or all of the printhead assembly, as referenced by function box 372, to correct for cross-scan position errors, using another transducer 373, or using drive signal correction techniques 374 and / or position feedback / adjustment techniques as already discussed.

[0087] Considering the principles discussed so far, correcting each of the substrate paths to a "virtual" linear edge, and the print head paths to a "virtual" linear edge, allows both the substrate and the print head to be positioned in a manner that conforms to the printing grid assumptions (e.g., the printer's coordinate reference system) despite minute errors imparted by the mechanical system. These techniques may optionally be combined with drive control techniques (or other described techniques for correcting each transport along that transport dimension) to further improve system accuracy. Again, these techniques can also be extended to other motion dimensions and process and / or mechanical systems.

[0088] FIG. 3E presents another example 375, an alternative embodiment in which errors in one transport path can be corrected using one or more transducers “T” associated with a second transport path. In this case, the gripper assembly can be assumed to include two linear transducers, again controlled in common and differential modes to achieve cross-scan offset and rotational correction without a fixed pivot point. Note that in this illustration, the errors are again on the micron or nanometer scale. The depicted angles and offsets are therefore greatly exaggerated in the illustration to aid in explanation. In this case, the illustration shows icons for “two grippers,” but in reality, these represent the exact same gripper and its position along the “in-scan” dimension for two separate scans. However, in this case, one of the transport paths (i.e., path 356 with respect to the printhead assembly) does not have its own transducer-based error correction system (or optionally, it has such a system, but the illustration corresponds to an implementation in which the gripper's error correction system would be further driven to correct for coordinate axis non-orthogonality). The gripper error correction system is therefore controlled in this example to also correct print head transport path jitter orthogonal to light beam 371, or for non-orthogonality between transport paths. That is, detected deviations (or non-orthogonality) in the print head transport path are corrected in this example by adding an additional mitigating offset into gripper second component 303, for example, by combining multiple transport system deviation / error corrections from the desired path. In this embodiment, therefore, the two grippers should be assumed to represent two alternative sets of transducer control signals that respectively correct print head system errors (or non-orthogonality) {Δi0, Δj0, and Δφ0} at print head position 373′ and print head system errors (or non-orthogonality) {Δi1, Δj1, and Δφ1} at print head position 373″ (i.e., corresponding to the individual scans).That is, with reference to FIG. 3B, through the use of mitigation offsets and angles provided by the transducers of the gripper system, even if the gripper transport in the "y" dimension is ideal (with respect to the gripper transport path). Even though the translated edges 107'" and 107'" are supposed to be corrected to the intended edges, in one embodiment, these same transducers may also be used to correct for errors in the print head path (or other errors). As depicted, additional offsets and / or rotations are added to effectively reposition the substrate to have its intended position and orientation relative to the print head (e.g., to generate motion in a manner that matches the print head errors, as represented by the alternate translated edges 107'" and 107'"). Other error correction techniques can also be applied to enhance these processes.

[0089] As the foregoing discussion implies, while the previous examples illustrate the correction of errors within one or two transport paths, the principles described with reference to FIG. 3E can be applied to correct for minute errors within any number of transport paths, e.g., one, two, three, four, five, etc., where corrections for multiple transport paths are applied to correct for errors within a first number of transport paths via mitigation corrections applied to a single drive path (e.g., to a transducer used for substrate transport) or to a second, fewer transport path. As noted, the present discussion also applies to correcting for non-orthogonality, e.g., where the gripper and printhead transport paths are not exactly 90 degrees separated. This can be treated as equivalent to the case of measured printhead x-position-dependent errors, with corresponding corrections applied by offsetting the transported components in either transport system. It should also be noted that while the term "transport path" is illustrated in the figures as a change in position along a curved path, the principles and fine error correction procedures discussed above can also be applied to correct for fine errors in any dimension (i.e., including rotation and precise angular orientation); for example, in embodiments in which the mechanism is rotated, it is possible to measure the rate of angular change or orientation "jitter" and use transducers and / or drive signal corrections as illustrated above to correct for such fine errors. Finally, while FIG. 3E illustrates incorporating printhead transport path errors (or other non-gripper errors) into gripper corrections, it is contemplated that these various transport paths are interchangeable; for example, gripper system position errors may be corrected using printhead system error correction transducers.

[0090] FIG. 3F shows that the techniques presented above can be embodied in many different forms to correct transport path errors, generally represented by numeral 381. In the context of a printer for manufacturing applications, a printing recipe can be pre-stored or cached in a manner that would be used to reproducibly print on many substrates on a continuous basis as part of an assembly-line type process, for example, as indicated by numeral 382. As a non-limiting example, the techniques described herein can then be applied to correct for minute motion errors along a path associated with substrate motion, motion of one or more printheads or printhead assemblies, motion of a camera assembly or inspection tool, etc. Note that one advantage of a system designed to drive errors to zero is that the effects of various other environmental variables, such as temperature, can be largely ignored from an error correction perspective; path deviations drive path corrections such that the in-transit position and orientation accurately matches the motion of the light beam or guide, whatever the temperature. These techniques enable automatic correction of motion along these transport paths for minute errors, such that the motion of the substrate (or, optionally, any of these systems) corresponds to an ideal path, even though the actual transport drive mechanisms (e.g., motion of grippers, edge guides, travelers, etc.) are still hampered by path errors that impart unintended offsets, nonlinearities, and other errors. Generally speaking, the corrections are made by a subsystem that is independent of the print recipe, in a manner that enables print planning and assumes the substrate is ideally positioned. For example, the structures described herein, in one embodiment, provide a means for countering errors or unintended offsets "Δx" in a first dimension relative to the transport path, where the first dimension is independent of the transport path (meaning it includes at least one component orthogonal to it). Such a means may be represented by numeral 383 in FIG. 3F. The transport path positioning means may include at least one transducer controlled in response to the transport path position to reduce or eliminate "Δx." Such means generally include transducers electronically controlled to achieve positional displacement in response to dynamic errors that vary according to position along the transport path and / or other factors. As represented by numeral 384, these structures (or different, potentially overlapping sets of structures) can define a virtual edge at a specific, arbitrary location in the first dimension (e.g., at "x3" in the embodiment from FIG. 3F) and provide a means for offsetting the gripper component to such location relative to the transport path (or the structure being transported). As before, such means also generally include a transducer and associated hardware and / or instruction logic that causes the transducer to neutralize or equalize the error. In another embodiment, as per numeral 385, the structures described herein provide a means for countering error "Δy" in the second dimension relative to the transport path. This second dimension is optionally independent of the transport path, but can (alternatively) represent a common dimension to the transport path, or may otherwise be generally synonymous with the transport path. Such means may optionally comprise at least one transducer controlled in response to the transport path position (and / or other factors) to reduce or eliminate "Δy," such as, for example, with respect to the embodiments depicted above, by correcting the position of the transported "thing" or otherwise adjusting the speed or motion along the transport path, or using a position feedback system as already referenced. In yet another variation, the same structure that may be applied to counteract "Δy" by numeral 386 may provide means for defining a virtual edge at a specific (absolute or relative) position in the second dimension (e.g., at a non-zero "y3" for the above embodiments) and offsetting the transport path (or the structure being transported) to such position. Such means also generally comprise a transducer and logic that causes the transducer to effect positional displacement in response to dynamically sensed error as the object is advanced along the transport path.In one embodiment, the means can include another transport path or associated error correction system, such as an error correction system associated with printhead transport (e.g., to compensate for nozzle firing time, substrate, printhead or other position errors, or other sources of error). In yet another embodiment (387), a transducer similar to that discussed above can be applied to counter rotational errors (Δθ). In one embodiment, the means can include a single transducer that converts electrical energy into structural rotation, while in other embodiments, two or more position transducers can be applied with the same intent. For example, as discussed above, one implementation can use two voice coils, each a linear transducer that, when operated independently, provides rotational adjustment of what is being transported, and a floating mechanical pivot mechanism is used to support the voice coils and provide structural rigidity. These structures (or different, potentially overlapping sets of structures) can also provide means for defining a virtual edge (388) in a specific (absolute or relative) angular relationship with respect to the first and second dimensions discussed above (e.g., "θ3" in the above embodiment) and for offsetting the transport path (or the structure being transported) in a manner corresponding to such orientation. In yet another embodiment (389), the structures described herein provide means for accommodating an offset "Δz" in a third dimension relative to the transport path, the third dimension optionally being independent of the transport path and the first and second dimensions referenced above. Such means can again comprise at least one transducer controlled by hardware and / or software logic in response to dynamically measured error to reduce or eliminate that error. The transducer and supporting logic can also be used to define a virtual edge in Z3 (390). Numeral 391 and the associated set of ellipses allow these techniques to be applied to multiple degrees of freedom, including correction and / or offset of any of the three positional dimensions and any of the three rotational dimensions (i.e., yaw, pitch, and / or roll).In some embodiments, means for correcting misalignment, as represented by numeral 393, can be applied to align the substrate with the printer's coordinate reference system. Such means can include position sensors such as cameras, handlers or other transport devices, processors, and associated support instructions and / or hardware logic for repositioning the substrate relative to the desired print (or conversely, adjusting the print to match a misaligned substrate). Means for correcting print head (PH) errors and / or aligning the print head (PH), as referenced above, can include a floating pivot point and / or a converter with support for common and differential correction modes, as referenced above. As represented by numeral 396, the system can also include means for realigning or adjusting the light source (e.g., by adjusting the laser attitude and yaw) to provide a calibrated path and / or printer coordinate reference system. The system can also include means (397) for correcting non-orthogonality of the coordinate reference system.

[0091] It should be noted that each reference to a dimension, e.g., "x," "y," "θ," or other dimension, is arbitrary, i.e., they may refer to any dimension and are not limited to Cartesian, rectangular, regular, or rectilinear coordinates. In one embodiment, the "x" and "y" dimensions correspond to the "cross-scan" and "in-scan" dimensions of the processing system, respectively, although this need not be true in all embodiments.

[0092] By correcting for motion errors in such a manner, the described processes provide a "virtual" and / or ideal and / or straight transport path, even though the mechanical motion system may still be disturbed and may continue to track existing, repeatable imperfections. When applied in the context of manufacturing systems, such as the aforementioned industrial printers, these techniques provide powerful tools to enable precision positioning and manufacturing.

[0093] II. ONLINE AND OFFLINE PROCESSES ASSOCIATED WITH SEGMENTED SHAFT MANUFACTURING SYSTEMS Figures 4A-5 will be used to discuss some details associated with a typical split-axis processing system. Figure 4A will be used to discuss a typical scanning motion used in the processing system to deposit materials that will form layers of an electronic device, and therefore, Figure 4B will be used to discuss the configuration of a specific manufacturing system that relies on a printer and processing chamber. Figure 4C will be used to discuss a process in which each substrate in a series of substrates is aligned with a coordinate reference system used by the printer, while Figure 5 will be used to discuss the processing of an electronic device (or a specific layer of such a device).

[0094] More specifically, FIG. 4A depicts a substrate 401 with several dashed-line boxes representing individual panel products. One such product, seen in the lower left of the figure, is designated using reference numeral 402. Each substrate (in a series of substrates) has, in one embodiment, several registration marks, as represented by numeral 403. In one embodiment, two such marks 403 are used on the substrate as a whole, allowing measurement of the substrate position offset relative to the mechanical components of the printer (e.g., grippers); in another embodiment, three or more such marks 403 are used to facilitate additional adjustments (e.g., rotational adjustments). In yet another embodiment, each panel (such as any of the four depicted panels) is accompanied by a per-panel registration mark, such as mark 405; this latter approach allows gripper adjustments so that each individual panel being printed is precisely aligned to the printer's coordinate reference system. Whatever approach is used, one or more cameras 406 are used to image the registration marks to identify the substrate position relative to the printer's coordinate reference system. In one embodiment, cameras are mounted on each of the gripper and advance printhead assemblies, and these cameras can each be controlled to image one or more substrate fiducials and identify precise substrate (and / or product) position and orientation relative to their position along the printer's transport axis (i.e., relative to the printer's coordinate reference system). In an embodiment, a single stationary camera is used, and the printer's transport mechanism (e.g., a handler and / or air-floating mechanism) moves the substrate to sequentially position each registration mark within the single camera's field of view. In a different embodiment, the camera is mounted on a two-dimensional motion system for transport relative to the substrate. In yet another embodiment, low- and high-magnification images are taken, the low-magnification image coarsely locating a fiducial for the high-resolution magnification, and the high-magnification image identifying a precise fiducial position according to the printer coordinate system. Line or CCD scanners can also be used. Considering the previous discussion, in one embodiment, the printer's transport mechanism (and associated feedback / position detection mechanism) controls the motion to within about 1 micron of the intended position, and an imaging system is used for each substrate to align (and optionally mechanically reposition) the substrate to the printer's coordinate reference system until reasonably accurate alignment is achieved. In another embodiment, the measured position and / or orientation errors can be used to customize / adjust a printing recipe in software so that the print is skewed to match the detected substrate position / orientation.

[0095] In a typical implementation, printing will be performed to deposit a given layer of material over an entire substrate at once (i.e., using a single printing process that provides layers for multiple products). Such deposition can be performed within individual pixel wells (not shown in FIG. 4A; there would typically be millions of such wells for a television screen), such as depositing an emissive layer within such wells, or on a “blanket” basis, such as depositing a barrier or protective layer such as an encapsulation layer. Regardless of which deposition process is in question, FIG. 4A shows two illustrative scans 407 and 408 along the long axis of the substrate. In a split-axis printer, the substrate is typically moved back and forth (i.e., in the direction of the depicted arrows), with the printer advancing the printhead positionally (i.e., perpendicular to the page) between scans. Note that while the scan path is depicted as linear, this is not required in every embodiment. Also, while the scan paths (e.g., 407 and 408) are illustrated as being adjacent and mutually exclusive in terms of area covered, this is also not required in every embodiment (e.g., the printhead can be applied on a portion-by-portion basis to swaths of printing as needed or desired). Finally, it should also be noted that any given scan path typically passes across the entire printable length of the substrate, printing layers for multiple products in a single pass. Each pass uses nozzle firing decisions according to a printing recipe, and controls on the transducers (not shown in FIG. 4A ) are used to ensure that each drop in each scan is deposited precisely where it should be deposited relative to the substrate and / or panel boundary.

[0096] FIG. 4B illustrates one contemplated multi-chamber processing apparatus 411 that can be used to apply the techniques disclosed herein. Generally speaking, the depicted apparatus 411 includes several general modules or subsystems, including a transfer module 413, a printing module 415, and a processing module 417. Each module maintains a controlled environment so that printing, for example, can be performed by the printing module 415 and other processes can be performed in a first controlled atmosphere, while another deposition process, such as inorganic encapsulation layer deposition (e.g., for the printed material) or curing process, can be performed in a second controlled atmosphere. These atmospheres can be identical, if desired. The apparatus 411 uses one or more mechanical handlers to move substrates between modules without exposing the substrates to an uncontrolled atmosphere. Within any given module, other substrate handling systems and / or specific devices and control systems can be used that are adapted to the processes being performed for that module. Within the printing module 415, as discussed, mechanical handling can include the use of floating tables, grippers, and alignment / micro-error correction mechanisms (in a controlled atmosphere), as discussed above.

[0097] Various embodiments of the transfer module 413 can include an input load lock 419 (i.e., a chamber that provides buffering between different environments while maintaining a controlled atmosphere), a transfer chamber 421 (also having a handler for transporting substrates), and an atmospheric buffer chamber 423. Other substrate handling mechanisms, such as a floating table, can be used within the print module 415 for stable support of the substrate during the printing process. Additionally, an x-y-z motion system (such as a split-axis or gantry motion system) can be used to reposition and / or realign the substrate with the printer, to provide precise positioning of at least one print head relative to the substrate, and to provide a y-axis transport system for transport of the substrate through the print module 415. It is also possible to use multiple inks for printing within the print chamber, e.g., using separate print head assemblies, so that, for example, two different types of deposition processes can be performed within the print module in a controlled atmosphere. The printing module 415 can include a gas enclosure 425 that houses the inkjet printing system along with means for introducing a non-reactive atmosphere (e.g., nitrogen or a noble gas) and otherwise controlling the atmosphere for environmental conditioning (e.g., temperature and pressure, gas composition and presence of particulate matter).

[0098] Various embodiments of the processing module 417 can include, for example, a transfer chamber 426, which also includes a handler for transporting substrates. In addition, the processing module can also include an output load lock 427, a nitrogen stack buffer 428, and a curing chamber 429. In some applications, the curing chamber can be used to cure, bake, or dry the monomer film into a uniform polymer film. For example, two specifically contemplated processes include a heating process and an ultraviolet radiation curing process.

[0099] In one application, the apparatus 411 is adapted for the mass production of liquid crystal display screens or OLED display screens, for example, fabricating an array of (for example) eight screens at a time on a single large substrate. The apparatus 411 can support an assembly line-type process, such that a series of substrates are processed sequentially, one substrate being printed on and then advanced for curing, while a second substrate in the series is simultaneously introduced into the printing module 415. The screens produced in one embodiment can be used in televisions and as display screens for other forms of electronic devices. In a second application, the apparatus can be used in the mass production of solar panels in much the same manner.

[0100] The printing module 415 can be advantageously used in such applications to deposit organic light-emitting layers or encapsulation layers that help protect sensitive elements of an OLED display device. For example, the depicted apparatus 411 can be loaded with a substrate and controlled to move the substrate between various chambers in a manner uninterrupted by exposure to uncontrolled atmosphere during the encapsulation process. The substrate can be loaded through an input load lock 419. A handler positioned in the transfer module 413 can move the substrate from the input load lock 419 to the printing module 415, and after the printing process is complete, the substrate can be moved to the processing module 417 for curing. By repeated deposition of subsequent layers, each with a controlled thickness, a cohesive encapsulation can be built up to suit any desired application. Again, it should be noted that the techniques described above are not limited to encapsulation processes, and many different types of tools can be used. For example, the configuration of device 411 can be varied to place the various modules 413, 415, and 417 in different juxtapositions, and additional, fewer, or different modules can also be used. In one embodiment, the depicted device 411 can potentially be (e.g., different The substrate may be coupled with other modules and / or systems to produce other layers of the desired product (through processes). When the first substrate in the series is completed (e.g., processed to deposit the materials that will form the layer in question), another substrate in the series is then introduced and processed in the same manner, e.g., according to the same recipe.

[0101] While Figure 4B provides one example of a set of linked chambers or processing components, clearly other possibilities exist. The techniques introduced above can be used to control processing processes performed with the device depicted in Figure 4B, or indeed by any other type of deposition equipment.

[0102] Once printing is complete, the substrate and wet ink (i.e., the deposition liquid) can then be transported for curing or processing of the deposition liquid into a permanent layer. For example, a substrate can have the "ink" applied in the print module 415 and then transported to the curing chamber 429, all without destroying the controlled atmosphere (i.e., advantageously used to prevent moisture, oxygen, or particulate contamination). In a different embodiment, an ultraviolet scanner or other processing mechanism can be used in situ, for example, on a split-axis traveler, in much the same manner as the printhead / camera assembly described above.

[0103] FIG. 4C provides another flowchart for system alignment, with a series of steps generally designated using the numeral 431. The method begins with system initialization, per numeral 432. For example, this initialization can be performed at each power-up, or on an ad hoc (e.g., operator command) or periodic basis. Alignment / detection operation 433 is then performed with respect to the various transport paths, for example, to identify a common point as an origin or common reference point, and to identify the precise location of each nozzle within a coordinate reference system established by this point and position feedback (and position indicators) associated with each transport path. As shown on the left side of the figure, this operation (or system initialization) can be performed as desired, for example, after a maintenance operation, resulting in a change in the printhead or other system component (e.g., which may result in the nozzles being in a different location relative to the printer's coordinate reference system). Note that numeral 434 represents a typical printhead assembly configuration, i.e., an assembly carrying nine printheads (this may be one large assembly or several subassemblies, e.g., three "ink sticks," each carrying three printheads in a staggered configuration). In one embodiment, there may be between 256 and 1,024 nozzles per printhead.

[0104] Detailing the alignment procedure, as described by U.S. Provisional Application No. 62 / 459,402, a removable optical reticle can be mounted in a known position (e.g., coaxially) with the printhead assembly's "downward-facing" camera, and both the gripper and printhead are articulated along their transport paths until this camera and the gripper-mounted "upward-facing" camera "find" each other (i.e., they both image the reticle, e.g., positioned until each camera image finds an associated set of sight lines within the reticle or a directly associated captured image). This point can then be used to define a common reference point or origin of a coordinate reference system, as represented by numeral 435. Each transport axis is then moved so that one of the cameras images a fiducial associated with the other transport system. For example, by numeral 437, the gripper and printhead transport system are interlocked until the gripper's "up-facing" camera finds the fiducial or alignment marks on the printhead and uses a search algorithm to precisely locate the center point of each print nozzle along its individual transport path. The position of each motion system, i.e., gripper / printhead assembly, can then be precisely defined in terms of the printer's coordinate reference system (e.g., observing precise positioning facilitated by alignment marks from optical tape), allowing for precise definition of this fiducial or alignment mark within the printer's coordinate reference system, etc. Each nozzle can be precisely defined in terms of the printer's coordinate reference system, allowing for precise control over where droplets are ejected. For other potential sources of error, e.g., unintentional non-orthogonality between transport axes, this error can be detected using additional fiducials or alignment marks (e.g., fixed fiducials associated with the printer support table are imaged by one or both cameras per 439, and associated adjustments are made to the coordinate reference system, optical guide system, or recipe), or alternatively, the optical guide / laser can be adjusted as part of a manual or electronic calibration process per 440, until precise alignment and orthogonality is achieved.

[0105] Optionally, such a calibration process can be performed periodically, or whenever system parameters are changed, for example, a new printhead is introduced, potentially introducing nozzles at previously known locations relative to the printer's coordinate reference system.

[0106] During run time, the introduction of each substrate in the series can potentially introduce unintended misalignment between where printing should occur (relative to the printer) and where printing occurs (relative to the substrate). Each substrate therefore undergoes a position and / or orientation detection process, per numeral 441, and associated errors are incorporated into the electronic printing details or to reposition the given substrate for layer printing (so that printing occurs in precise alignment with the substrate fiducials, and with other layers deposited on the substrate that are also precisely aligned with these fiducials). As each given substrate in the series is introduced into the printing module (e.g., 415 from FIG. 4B), per numeral 442, it is first roughly aligned using one or more bankers and / or mechanical handlers. Once the given substrate and its associated fiducials are approximately in the correct position, an imaging system (such as a “downward-looking” camera system carried by the printhead assembly) is then employed, per numeral 443, using a search algorithm and suitable image processing to precisely locate one or more substrate fiducials. For example, this detection can be performed using a spiral search pattern or similar search pattern that searches for a reference expected position until a precise reference position and / or orientation is detected. A series of optional and / or alternative correction processes can then be employed to precisely position and / or reposition the substrate. For example, as variously indicated by process box 445, in one embodiment, the aforementioned transducers can be driven to provide precise substrate positioning (e.g., the vacuum lock of the gripper's "second component" is not adjusted, but the transducers are ganged in common drive mode and / or differential drive mode until the substrate reference has exactly the correct starting position and orientation). The transducer positions corresponding to this substrate position / orientation can then be used as zero levels or positions, and error corrections (during production) are then superimposed thereon or otherwise defined relative to these positions. Alternatively, or in addition, a mechanical handler can be used to reposition the substrate as needed.As yet another alternative, the recipe can be adjusted in software as disclosed in U.S. Patent Publication No. 20150298153 to correct for alignment errors (e.g., with correction of remaining reproducible errors related to transducers associated with the gripper and / or print head transport system, as previously referenced). Printing then occurs according to the desired printing recipe, per numeral 445. After printing, the freshly printed substrate is unloaded (e.g., transported to a processing chamber) for curing, while the system receives or prepares to receive a new substrate under robotic or human direction.

[0107] FIG. 5 illustrates several different implementation layers, collectively designated by reference numeral 501. Each one of these layers represents a possible separate implementation of the techniques introduced herein. First, techniques as introduced in this disclosure can take the form of instructions (e.g., executable instructions or software for controlling a computer or printer) stored on a non-transitory, machine-readable medium, as represented by graphic 503. Second, as represented by computer icon 505, these techniques can also optionally be implemented as part of a computer or network within a company that designs or manufactures components for sale or use in other products. Third, as illustrated using storage medium graphic 507, previously introduced techniques can take the form of stored printer control instructions as data that, when acted upon, will cause a printer to process one or more layers of a component, for example, relying on the use of different ink volumes or locations to mitigate alignment errors, as discussed above. Note that the printer instructions can be transmitted directly to the printer, for example, via a LAN. In this regard, the storage medium graphic can represent (without limitation) RAM within or accessible to the computer or printer, or a portable medium such as a flash drive. Fourth, as represented by processing device icon 509, the techniques introduced above can be implemented as part of a processing apparatus or machine, or in the form of a printer within such an apparatus or machine. It is noted that the particular depiction of processing device 509 represents one exemplary printer device, for example, as discussed in connection with FIG. 4B . The techniques introduced above can also be embodied as an assembly of manufactured components. For example, in FIG. 5 , several such components are depicted in the form of an array 511 of semi-finished flat panel devices that would be separated and sold for incorporation into end consumer products. The depicted device may have, for example, one or more emissive or encapsulating or other layers that are processed depending on the methods introduced above.The techniques introduced above can also be embodied in the form of end consumer products as referenced, for example in the form of a display screen for a portable digital device 513 (e.g., an electronic pad or a smartphone, etc.), as a television display screen 515 (e.g., an OLED TV), a solar panel 517, or other type of device.

[0108] Having thus discussed in detail the sources of positional error and associated remedies, the present disclosure will now turn to a discussion of more detailed embodiments of specific processing apparatus.

[0109] III. Specific Implementation 6A-6E are used to discuss specific printer implementations as applied to the manufacture of OLED displays or solar panels. Depending on the product design, the printers shown in these figures can be used to deposit layers for many products on a substrate at once (e.g., many smartphone or other portable device displays, perhaps hundreds at a time, as conceptually represented by the individual arrayed products on substrate 411 from FIG. 4A) or for a single product per substrate, such as the display screen of HDTV 415 or solar panel 417 from FIG. 4A. Many other exemplary applications will be apparent to those skilled in the art.

[0110] More specifically, Figure 6A shows printer 601 as having several components that operate to enable reliable placement of ink droplets on specific locations on a substrate. Printing in the illustrated system requires relative motion between each printhead assembly and the substrate. This can be achieved using a motion system, typically a gantry or split-axis system. Either the printhead assembly can move over a stationary substrate (gantry-type), or both the printhead assembly and the substrate can move, as in a split-axis configuration. In another embodiment, the printhead assembly can be substantially stationary while the substrate is moved along both the x and y axes relative to the printhead.

[0111] The printer includes a printer support table 603 and a bridge 605. The printer support table 603 is used to transport substrates (such as substrate 609) using a planar, floating support surface mounted by a frame 604, while the bridge 605 is used to transport several print heads and various support tools, e.g., optical inspection tools, curing devices, etc. As mentioned above, a gripper (e.g., a vacuum gripper, not seen in this figure) provides a “fast axis” for transporting the substrate (e.g., in what is referred to elsewhere herein as the “y” dimension (e.g., see dimension legend 602)), while the bridge allows one or more print head assemblies 611A and 611B to move back and forth along the bridge 605 along the “slow axis.” To accomplish printing, a print head assembly (e.g., primary assembly 611A) would be positioned at a suitable position along the bridge, while the vacuum gripper moves the substrate in a generally linear manner along the “y” dimension to provide a first scan or raster. The printhead assembly 611A or 611B is then typically moved along the bridge 605 to a different position and stopped, and the vacuum gripper then moves the substrate 609 back in the opposite direction under the new printhead assembly position to provide the subsequent scan or raster, etc.

[0112] The printer support table 603 can have a porous medium that provides a planar, floating support surface. The planar, floating support surface includes an input zone, a print zone, and an output zone, designated using numerals 606-608, respectively. A substrate 609 is depicted in the input zone 606, ready to be printed. A combination of gas positive pressure and vacuum can be applied through an array of ports or using a distributed porous medium provided by the support table. Such zones, with both pressure and vacuum control, can be effectively used to provide a fluid spring between the floating table surface and each substrate 609. The combination of positive pressure and vacuum control can provide a fluid spring with bidirectional stiffness. The gap that exists between the substrate 609 and the floating table surface can be referred to as the "fly height," and this height is adjusted by controlling the positive pressure and vacuum port conditions. In this way, the z-axis height of the substrate can be carefully controlled in various portions of the printer support table, including, but not limited to, within the print zone 607. In some embodiments, mechanical retention techniques, such as pins or frames, can be used to limit lateral translation of the substrate while it is supported by the gas cushion. Such retention techniques can include using spring-loaded structures, such as to reduce impulse forces incident on the sides of the substrate while it is being retained. This can be beneficial because high-force impacts between a laterally translating substrate and the retention mechanism can potentially cause chipping or catastrophic failure of the substrate. In other regions of the printer support table, the fly height need not be as precisely controlled, for example, within the input or output zones 606 and 608, or can be controlled to provide different fly heights or fly height profiles. "Transition zones" between regions, such as where the pressure-to-vacuum nozzle ratio gradually increases or decreases, can be provided. In an illustrative example, there can be an essentially uniform height between the pressure-vacuum zone, transition zone, and pressure-only zone, such that the three zones can lie essentially in a single plane within tolerances.The fly height of the substrate over the pressure-only zone elsewhere may be greater than the fly height of the substrate over the pressure-vacuum zone, such as to allow sufficient height so that the substrate does not collide with the printer support table within the pressure-only zone. In an illustrative example, the OLED panel substrate may have a fly height of about 150 microns (μ) to about 300 μ above the pressure-only zone, and then about 30 μ to about 50 μ above the pressure-vacuum zone. In an illustrative example, one or more portions of the printer support table 603 or other processing equipment may include an air bearing assembly provided by NewWay Air Bearing (Aston, Pennsylvania, United States of America). Porous media, such as those having physical dimensions defined to occupy the entire substrate 609 or a defined area of ​​the substrate, such as the display area or an area outside the display area, may be obtained from Nano TEM Co., Ltd. (Niigata, Japan), for example. Such porous media may include pore sizes defined to provide a desired pressurized gas flow over a defined area while reducing or eliminating mura or other visible defect formation.

[0113] In the embodiment of FIG. 6A , a handler or other transport system (not shown) delivers each substrate 609 to the input area 606 of the printer support table 603. A vacuum gripper engages the substrate 609 and transports it from the input zone 606 into the print zone 607, then moves the substrate back and forth for printing, achieving a discrete, "near-frictionless," low-particle-generating, high-speed scan along the printer's fast axis according to a particular recipe. When printing is finished, the vacuum gripper then transports the substrate to the output zone 608, where a mechanical handler takes over and transports the substrate to the next processing device. During this time, a new substrate can be received in the input zone 606, and the vacuum gripper is then transported back to that zone to engage the new substrate. In one embodiment, deposited droplets of ink are allowed to mix together in the output zone, for example, via a short rest or fixing cycle in which the substrate is allowed to remain in the output zone, and printing and fixing and subsequent curing are carried out in a controlled environment (e.g., generally in a nitrogen or noble gas atmosphere or other non-reactive environment).

[0114] The depicted printer 601 may also include one or more maintenance or administration bays 612A and 612B, each of which may store tools 615-620, e.g., printheads, cameras, and “ink sticks,” for modular engagement with one or both printhead assemblies. Similarly, in one embodiment, these bays are configured for interaction with other components, such as a drop measurement module, a purge basin module, a blotter module, and the like, optionally within the same enclosure volume or a second volume. In one embodiment, the printhead assembly can simultaneously carry three “ink sticks,” as represented by numeral 622, each supporting three printheads and supporting fluid and circuit contacts in a manner adapted for modular engagement with the printhead assembly. The ink delivery system (not separately shown in FIG. 6A) includes one or more ink reservoirs, ink supply tubing that carries ink between the reservoirs and one or more of the printhead assemblies, and suitable control circuitry, while the motion system (also not separately shown in FIG. 6A) includes electronic control elements such as a subsystem master processor and control system, actuation elements for the gripper and printhead assemblies, and suitable control code.

[0115] Each printhead assembly 611A / 611B includes a traveler 623A / 623B that rides along the bridge (i.e., on a track or guide) and an engagement mechanism 624A / 624B mounted adjacent the front face 625A / 625B of the bridge for robotically engaging and disengaging ink sticks or other tools, as desired, on a modular basis, using the respective support bays 612A / 612B. Each printhead assembly (611A / 611B) is supported by a linear air-bearing motion system (which is inherently low particle generation) or other linear motion system to enable it to move along the bridge 605. Each printhead assembly is accompanied by fluid and electronic connections to at least one printhead, each printhead having hundreds to thousands of nozzles capable of ejecting ink at a controlled rate, velocity, and size. By way of illustrative example, a printhead assembly can include from about 1 to about 60 printhead devices, each of which can have from about 1 to about 90 printheads, each of which can have from 16 to about 2,048 nozzles, each capable of ejecting droplets having a volume of from about 1 to 20 picoliters (pL), depending on the design. Front surfaces 625A / 625B each provide a separate z-axis movement plate that controls the elevation of the engagement mechanism (and thus the printhead or other tool) above the surface of the substrate. The traveler and engagement mechanism can serve as the "first" and "second" components previously referenced with respect to the printhead assembly; for example, these components are coupled, in one embodiment, by an electromechanical interface (not visible in FIG. 6A ) that enables robotic adjustment of the transported tool in each of the x, y, and z dimensions. In this regard, previously referenced U.S. Provisional Patent Application No. 62 / 459,402 generally provides details regarding z-axis calibration of the printhead and various other elements of the printer's coordinate reference system.The electromechanical interface can advantageously include stepper motors, fine adjustment screws, and other mechanisms for adjusting (a) the x-, y-, and / or z-mounting of each tool relative to its associated engagement mechanism, and (b) the pitch between individual tools (e.g., the pitch between ink sticks). In addition, each tool can also include various fine adjustment mechanisms, for example, for adjusting the pitch between multiple printheads carried by each ink stick. The electromechanical interface can optionally include kinematic or similar mounts for repeatably and reliably engaging each tool to within 1 micron of its intended position in each dimension, along with robotic adjustment mechanisms configured to provide feedback for precise positional adjustment of each tool relative to its engagement mechanism.

[0116] The electromechanical interface also advantageously includes a set of transducers as already referenced, e.g., to offset the engagement features 624A / 624B linearly in the "y" dimension relative to the associated traveler 623A / 623B. As should be apparent from the discussion thus far, the provision of a transducer correction feature that provides a "virtual straight edge" for the printhead and another "virtual straight edge" for the gripper (not seen in FIG. 6A ) promotes a more "regular" print grid, for example, helping to ensure uniform drop placement at the precisely regular spacing associated with the print grid, thereby promoting layer uniformity.

[0117] As should be apparent, the depicted structural elements enable control over substrate x-axis position using common-mode displacement of the substrate by a separate voice coil assembly, as well as control over substrate orientation about the θ dimension (i.e., rotation about the z-axis). Various embodiments of the depicted gripper systems can maintain substrate orientation parallel to the y-axis of travel within ±4,300 microradians or less, depending on implementation. As previously mentioned, when it is also desired to adjust substrate position to more closely match deviations in printhead (printhead assembly) position and orientation, this control over orientation along with common-mode x-axis displacement, and effective implementation of a floating pivot point for the substrate, enables precise repositioning of the substrate, simulating a complete virtual edge (or guide) for each substrate and traveler motion (e.g., printhead, camera, etc.). As previously mentioned, the vacuum gripper and printhead assembly / traveler each also include optical systems (not shown) for detecting registration marks, i.e., providing electronic position signals precisely indicating the location of the gripper or printhead assembly along the associated transport path.

[0118] As should be observed, the use of a voice coil in combination with air (gas) bearing support for the substrate and vacuum-based engagement between the gripper and substrate provides an efficient mechanism for frictionless, effective control of both substrate transport and fine positioning. This structure helps maintain minimal contact with the substrate during electronic component processing (e.g., during layer deposition and / or curing), which helps avoid distortions and defects that might otherwise result from substrate deformation, contact-induced local substrate temperature fluctuations, or other effects such as electrostatic energy buildup. At the same time, the near-frictionless support and transducer system, in combination, helps provide micron-scale or better throws used to implement fine adjustments of substrate position. These structures help implement precise substrate corrections necessary to obtain one or more "virtual transport paths," despite mechanical imperfections as already referenced, and despite the fact that the substrates serving as deposition targets can be meter-long and meter-wide. The voice coil can also be configured to provide relatively large throws, for example, from submicrons to 100 microns or more, which can be important depending on the implementation (e.g., when the system in question is subject to jitter on this scale given its manufacturing tolerances).

[0119] FIG. 6B shows vacuum gripper 631 in additional detail. Vacuum gripper 631 again comprises a first component 633 (riding on a y-axis carriage, not visible in the figure), a second component 635 that engages the substrate, and two linear transducers 637 and 639. As depicted, the second component is positioned vertically above the first component as both are advanced along the gripper's transport direction (e.g., along the "y-dimension" depicted by legend 632), and note that the second component supports a vacuum chuck 643 that is used to selectively engage the substrate. Unlike previous examples that assume the use of a virtual pivot point, this example further includes a floating mechanical pivot assembly or mechanism 641 that provides a mechanical linkage between first and second components 633 / 635 as the gripper is advanced along the y-dimension and helps provide structural support for embodiments in which the linear transducers are embodied as voice coils. The floating pivot mechanism includes a pivot shaft 651, an assembly top plate 653 (mounted to the gripper second component 635), and an x-axis sliding bottom plate 655 that moves on rails relative to a support frame 644 provided by the gripper first component 633. The assembly top plate is preferably made of a relatively thin material to provide flexure and allow leveling of the gripper second component relative to, for example, the substrate and floating table, and is rigidly secured to the second gripper second component using a mounting bracket 656. Briefly, as component 633 is advanced along the y dimension, the floating mechanical pivot mechanism 641 constrains component 635 to similarly advance along the y dimension while allowing x-axis sliding interaction between these components 633 / 635 and rotation about the floating pivot axis 649.

[0120] The floating pivot point allows for differential or common mode drive of transducers 637 and 639, as discussed above. These various motions are further represented by sets of motion arrows 645 / 647. Generally speaking, each transducer couples a mounting block 657 (e.g., mounted relative to frame 644 of the gripper's first component) and a mounting plate 661 (mounted to the gripper's second component), and a linear actuator 659 couples the mounting block and mounting plate to provide precision displacement along the x-axis. The design of transducers 637 / 639 and floating mechanical pivot mechanism 641, as represented by dashed outlines 663 and 665, will be shown and discussed in further detail in connection with Figures 6C and 6D.

[0121] FIG. 6B also illustrates the positioning of the optical guide 667 relative to the various components of the gripper. In this design, the beam of light is above the top surface of the gripper's offsettable component (635), but below the plane occupied by the substrate. Such a configuration facilitates ease of access for adjusting the optical components for proper alignment. In an alternative embodiment, the optical guide (i.e., the beam of light in this example) can be directed into the cavity between the gripper's first and second components 633 / 655; therefore, the beam is seen with a half-dashed line traversing the gripper to represent that the beam may be hidden from view in this particular location in such an alternative embodiment, as represented, for example, by numeral 667′. Per-transducer beam splitters 668 are also mounted to the gripper's second component 635 and are used to redirect the laser light from the optical guide to per-transducer detectors, represented by numeral 669. The design of the beam splitter and / or detector 668 / 669 for each transducer advantageously features adjustment screws to adjust the beam splitter and / or detector so that they can be aligned, for example, so that the detector reads zero error when the second component of the gripper is ideally positioned relative to the pre-aligned optical guide (667). These various elements are also mounted, in one embodiment, below the plane occupied by the substrate, but on the top surface of the offsettable component 635 of the gripper. In alternative embodiments, these elements can be mounted elsewhere (e.g., between components 633 and 635, i.e., below the top surface of component 635 in a manner hidden from view). The beam splitter, detector, and adjustment screws are each advantageously positioned to be accessible (e.g., using a screwdriver or other tool) to allow offline adjustment for purposes of this calibration. In alternative embodiments, proper beam splitter and / or detector alignment can be detected, or misalignment can be detected and otherwise incorporated into the correction process.For example, in one embodiment, a test substrate can be introduced, fiducials on the test substrate can be imaged at multiple locations, the misaligned light beam, beam splitter, and / or detector can have readings at different transport path advance positions that are stored and incorporated into the error correction process at run time, and the transducer correction signal is effectively "skewed" at run time to ideally advance the second component of the gripper based, for example, on pre-programmed adjustments to the readings of the misaligned optical guide or associated optical components. It should also be pointed out that in various other embodiments, the optical components can be configured differently, for example, the detector can be mounted separately from the gripper, and / or the light source can be mounted on the component being transported, and / or various components can be mounted elsewhere.

[0122] Of note, FIG. 6B also shows an “up-looking” camera 670 that, as previously described, is used to image fiducials through a focal path 669 (represented in FIG. 1 as an optical cone) for purposes of aligning the vacuum gripper and printhead assembly (not shown) to define the printer's coordinate reference system and to identify the relative distances and positions of various printhead assembly components (e.g., precise printhead nozzle positions and a printhead assembly camera, not shown, in terms of the printer's coordinate reference system).

[0123] Figure 6C shows a close-up view of linear transducer 637 from Figure 6B. Again, the other transducer (designated by numeral 639 in Figure 6B) is substantially identical or symmetrical in design to transducer 637.

[0124] More specifically, the linear transducer, in this example, assumes a voice coil design with gripper first and second components 633 / 635 supported on air bearings. The voice coil is contained within a cylindrical housing 659 to allow displacement of the first component (e.g., vacuum chuck bar and substrate) relative to the second component along the general direction of double arrow 645. Adjustment plate 670 advantageously allows fine adjustment of the transducer xyz orientation as between these two components to linearly move the second component along the x-dimension axis (see dimension legend 632 in FIG. 6B ). Again, this can be provided with a manually adjustable screw configuration that is adjusted and / or calibrated infrequently. The voice coil in this embodiment has a magnet-based design that provides a fast, precise microscopic throw and displaces mounting plate 661 toward and away from mounting block 657 in response to an electronic control signal, i.e., again in the direction of double arrow 645.

[0125] FIG. 6D shows the floating mechanical pivot mechanism 641 from FIG. 6B. As previously mentioned, the assembly top plate 653 carries a bushing that allows pivoting of the assembly top plate (and gripper second component and vacuum chuck) about pivot axis 649. This axis is defined by a pivot shaft 651 that extends vertically downward, parallel to the z-dimension, and is coupled to an x-axis sliding bottom plate 655. Although not visible in the figure, the x-axis sliding bottom plate 655 is generally coupled to the gripper first component by rails (via the support frame 644) to allow relatively frictionless x-axis displacement of the assembly top plate 653, pivot shaft 651, vacuum chuck 643, and gripper second component 635 relative to component 633 (and support frame 644), while simultaneously constraining these two components 633 / 635 to move together in the y-dimension. This structure provides mechanical support for the floating pivot point, and common-mode and differential-mode voice coil displacements are used to provide error-mitigating offsets for the second component along the directions of arrow 673 and rotational arrow 675, respectively. Note that a floating pivot point is not required for all embodiments; for example, in embodiments where the transducers provide sufficient output impedance, the mechanical pivot mechanism could potentially be omitted. Regardless of whether a mechanical support structure is used, the floating pivot point advantageously enables common-mode and differential-mode control for multiple transducers to reposition the substrate in the x and θ dimensions, thus approximating a "straight-edge" ideal transport path. Various modifications and equivalents will no doubt occur to those skilled in the art.

[0126] FIG. 6E provides a schematic diagram 681 illustrating elements of the pivot mechanism represented by FIGS. 6B-6D. More specifically, this figure illustrates linear x-axis rails 683 that effectively provide bearings 685 on either side of x-axis sliding lower plate 655, allowing the structure (and everything supported above) to ride in and out of the drawing page. At the same time, assembly top plate 653 mounts bushings 686 to allow free rotation of that plate relative to x-axis sliding lower plate 655 about pivot axis 649. More specifically, bushings 686 support bearings 689 and enable this rotation. FIG. 6E also illustrates the flexure provided by assembly top plate 653 relative to gripper second component 635 and transducers 637 / 639.

[0127] While the transducer correction mechanisms depicted in Figures 6A-6D are illustrated in connection with a gripper assembly, the same basic structure can also be used for the printhead assembly (or each printhead assembly or other tool carrier). Specifically, a first component rides on a track (or x-axis carriage assembly) on gas bearings, while a second component carrying the printhead (or other tool) is displaced in the "y" and / or "z" dimensions depending on the position error in that dimension as a function of the x-axis position (and / or other factors, e.g., temperature). For corrections in a given dimension, two transducers are used, again in conjunction with a virtual or floating pivot point, to achieve both y and θ corrections (or z and xz plane angle corrections) in the relative position of the printhead to the substrate, and in doing so, cause the printhead to follow a virtual straight edge path. Optionally, two such correction mechanisms can be used together to provide a straight edge path for each gripper and printhead transport system, respectively, effectively providing a very precise regular printing grid, providing further precision over droplet placement. The printhead Z-axis adjustment can also be controlled using a similarly designed transducer-based motion correction system to provide altitude correction of the printhead orifice plate relative to the substrate surface, thereby managing altitude differences and also with improved accuracy. Other degrees of freedom may also be similarly corrected. In precision motion systems, particularly printer-based processing systems where the coordinate reference system used for printing / manufacturing is effectively related to multiple transport paths, the use of multiple correction systems of this type improves precision across droplet landing locations, thus promoting greater uniformity in the processed layers. This, in turn, makes it easier to produce thinner layers, e.g., having thicknesses of 5 microns or less. Again, while the designs discussed above emphasize the use of “virtual straight edges” for the purpose of improving the regularity of the printing grid, it should be noted that not all embodiments are so limited, and nearly any desired “ideal” path can be approximated using the teachings provided herein.

[0128] IV. Various Use Cases, Revisited 7A-7I are used to review some specific use cases for the techniques introduced above.

[0129] More specifically, FIG. 7A shows an embodiment 701 in which an optical guide 702 is used to ensure linear motion of a gripper 703 and a substrate 704. The depicted structure implements a continuous process performed in real time. A robotic gripper (not shown) holds the substrate as it is advanced through the transport system. In the depicted embodiment, the light beam 702 (i.e., the beam generated by the laser source 705) ideally remains parallel to the substrate and at a constant distance from it as the latter is advanced through the system (this is represented by an imaginary linear edge 711). To the extent deviations occur, the offset (in linear position) and rotation of the second component of the gripper relative to the beam 702 is measured by two laser sensors 706A / 706B. Path deviation measurements from the two laser sensors allow two actuators 707A / 707B (e.g., piezoelectric transducers, voice coils, etc.) to adjust their rotational angle 709 (with respect to an optional mechanical pivot assembly 708) and linear position 710 along a direction perpendicular to the beam to maintain an "ideal" relationship between the second (offsetable) component of the gripper and the beam.

[0130] 7B shows another embodiment 713, but this time the laser source and / or optics 714 are mounted in a fixed relationship to the “thing” being transported, and the sensor 715 is stationary. Differential readings from the sensor over time can be used to detect and correct, for example, rotational errors, and steady-state beam misalignment can be used to detect and correct the linear position of the thing being transported in a direction orthogonal to the beam 716. As shown by the extended dashed line 717, one variation of this configuration features a stationary laser source such that the beam is directed at the item being transported along line 717 and redirected to the sensor by optics 714 mounted on an offsettable component in a manner that allows detection of deviations from a desired path. Many variations will occur to those skilled in the art, and any mechanism is contemplated, for example, in which a light source or other radiation source, beam, detector, etc. is used to detect positional deviations. In other embodiments, without limitation, the laser source and detector may both be stationary while the optics (flat or curved mirrors or beam splitters) are mounted in a fixed manner relative to the offsettable components in a manner that facilitates detection of positional deviations. Whatever design is used, signals from the sensors are again used to direct the actuators 718A / 718B to maintain beam alignment.

[0131] FIG. 7C shows an embodiment 719 in which a sensor 720 is used to calibrate a light source 721, for example, to detect and / or correct path error 722 relative to an intended path 723. A laser sensor near the laser source is used to optically measure the laser beam direction. If the laser beam direction deviates from the intended path 723, the position of the laser and / or the deflection of its beam is adjusted (manually and / or electronically under the influence of electronic control signals) until the intended path is achieved. For example, in one embodiment, the laser mount can be controlled by a piezoelectric (or other) transducer or other deflection means 724 (under the influence of processing circuitry 725) to adjust the tilt and / or rotation of the laser source until proper alignment is obtained. Note that the laser sensor can advantageously be designed to detect path deviations in two dimensions and ideally effect correction of the alignment error using an automatic control loop with a response within a few milliseconds. It should also be noted that the design of a suitable laser sensor is within the level of one skilled in the art; for example, in some embodiments, a beam splitter and a quad-cell sensor may be used to align the beam, as previously referenced. Many suitable adjustment and sensing mechanisms will occur to those skilled in the art of optics, including, but not limited to, those based on analog designs (e.g., where an analog output is generated using a voltage proportional to position or deflection), convex or concave mirrors and beam splitters, interferometry, and other mechanisms.

[0132] FIG. 7D shows another embodiment 727 in which the light source 728 is improperly aligned. However, unlike the embodiment of FIG. 7C, deviations between the incorrect optical path 729 and the correct optical path 730 are passively and electronically mitigated, for example, by using a first sensor 731 to detect the error and actuators 732A / 732B to implement compensating offsets. Signals controlling these offsets can be stored in digital memory 733 and retrieved during system operation, or otherwise added to dynamic corrections (identified at run time from a second sensor 734A / 734B) depending on the transport path position so that the transported object follows the correct path 730. FIG. 7D shows an additional laser position sensor 731 on the left side near the end of the laser beam. This sensor allows for the elimination of sensor 720 (and the associated active laser attitude control depicted in FIG. 7C). That is, instead of actively correcting the laser alignment error, the error is measured by the additional laser sensor 731 and corrected using two transducers (ie, depending on the substrate position, while moving the substrate).

[0133] FIG. 7E illustrates an embodiment 735 implementing a zero target control loop. Sensors 736A / 736B dynamically detect deviations from a desired path in one or more dimensions (in this case, represented by the deviation between a “line of sight” 737A / 737B and a beam 738 from a laser source 739). Processing electronics 740A / 740B preprocess the output from the sensors so that a zero signal is the norm (indicating “no adjustment”). This output is provided to a motion controller (i.e., a processor-implemented zero target controller) 741, which generates a correction signal and provides feedback to drive transducers 742A / 742B when correction is required, i.e., to always drive the error to zero. FIG. 7E does not explicitly show the method used to correct the laser alignment error; however, without limitation, either the active control method introduced for FIG. 7C or the transducer compensation method represented by FIG. 7D could be used for this purpose, and other methods will occur to those skilled in the art.

[0134] 7F shows an embodiment 745 in which actuators 746A / 746B are driven to maintain the transported object (e.g., gripper 747 and substrate 748) horizontal in terms of z-axis elevation relative to a beam or optical guide 749. In this case, sensors 750A / 750B detect deviations of the gripper (or other transport mechanism) from the optical guide 749 and drive the two actuators 746A / 746B to even out jitter in elevation or otherwise precisely control the elevation (e.g., to maintain a pre-determined elevation profile, such as to match a zone, as previously referenced). A processor-based motion controller 751 can again be used to assist in this purpose.

[0135] FIG. 7G shows an embodiment 755 using two parallel transport systems 756A / 756B for a given transport direction. In this case, whether due to the size of the substrate being received or other details of the manufacturing process, it is assumed that a substrate or other transported element 758 will be transported by multiple travel components along a parallel transport path, and it is desirable for each transport system (i.e., each of the two parallel vacuum gripper systems in this example) to be precisely synchronized and controlled to avoid mechanical jitter and / or substrate tilt. To this end, each parallel transport system 756A / 756B generally has its own optical guide or beam 757A / 757B and transducer compensation system 759A / 759B, each corresponding to one of the embodiments described herein. Sensor pairs 761A / 761B and 762A / 762B report signals to a motion controller circuit 763, which controls two motors (not shown), one corresponding to each transport system 756A / 756B. One of the transport systems 756B also carries another light source 765 (e.g., a laser source) that further generates a third optical guide 766, while the other transport system 756A carries a third sensor 767, e.g., a four-cell design as described above. As shown in phantom, path deviation signals from each of the five sensors 761A / 761B / 762A / 762B and 767 are fed to a motion controller circuit that advances or retracts one or both of the motors so that each of the parallel transport systems 756A / 756B advances precisely in parallel. For embodiments using multiple transducer correction systems (e.g., to control both x-offset and z-altitude for each lateral displacement and / or flight altitude control), signals from the third optical guide 766 and third sensor can be used to detect altitude differences between the second offsettable components (i.e., for each gripper system in this embodiment).Similar to Figures 7C-D, the components associated with the third optical guide may optionally further include components used during a calibration mode or process to ensure that the third optical guide is horizontal and perpendicular to the direction of transport provided by the parallel conveying system 756A / 756B.

[0136] 7H shows an embodiment 771 in which two conveying systems 772 and 773 used for the orthogonal transport path each have their own individual laser source 774 / 775 and associated optical guides 777 / 778 and motion controllers 780 / 781. The result is that each motion controller 780 / 781 receives an individual drive or command signal 782 / 783, i.e., as an absolute position command, and errors are corrected transparently to the general system motion control so that it can establish the appropriate position relative to the system coordinate reference system.

[0137] Figure 7I shows an embodiment 787 in which two transport systems 788 / 789 each have their own source 790 / 791 and sensor pairs 792A / 792B and 793A / 793B, but only one transport system has an actuator 794A / 794B that corrects motion jitter. In this case, a motion controller 795 generates transducer control signals 796A / 796B such that actuators 794A / 794B are driven to compensate for errors associated with the other transport system 788, as introduced above in connection with the discussion of Figure 3E. Non-motion errors, such as errors in the alignment of optical guides related to either the transport systems and / or non-orthogonality between the transport systems, can also be corrected, as already introduced (this non-orthogonality is represented by two depicted erroneous beam paths 797A / 797B). As represented by the individual correction signals 798A / 798B sent to each laser source 790 / 791, one or both light sources can be calibrated electronically (or by incorporating any of the optional alignment / calibration techniques already introduced) to correct for non-orthogonality, for example, by realigning the laser paths, adjusting the correction signals provided to the actuators 794A / 794B, etc.

[0138] While various options and use cases are described above, it should be noted that the various techniques and options are considered optional and could be mixed and matched with one another in any permutation or combination. As a non-limiting example, it is possible (and explicitly contemplated) that the embodiment of FIG. 7H could employ a zero target controller (and associated "line of sight" sensor, introduced above in connection with the embodiment shown in FIG. 7E). Other combinations, permutations, and modifications similar to one or more of the examples discussed above will no doubt be apparent to those skilled in the art.

[0139] V. Multidimensional Control of Offsetable Conveying System Components One embodiment of such a gripper error correction system can correct errors in multiple dimensions, orthogonal to the transport path and / or orthogonal to the optical guide. As illustrated above, in an environment where a transport system moves a transported component along a first translation axis (e.g., along the “y” axis of motion), a set of one or more actuators or transducers, such as a voice coil or piezoelectric transducer, can be used to offset the transported component along a second translation axis (e.g., along the “x” axis of motion), while a set of one or more actuators or transducers, such as a voice coil or piezoelectric transducer, can be used to offset the transported component (or another component) along a third translation axis (e.g., along the “z” axis of motion), all three of which are mutually orthogonal. In another embodiment, three or more actuators can be used per offsettable component to promote equalization of that component. These various design options will be discussed below in connection with FIGS. 8A and 8B.

[0140] 8A is a cross-sectional view of an assembly 801 that uses two different sets of transducers "T" to correct for errors in more than one dimension. More specifically, a first track-guided component 803 of the transport system travels along a first dimension of travel (i.e., in this example, along the "y" axis into the page of the drawing), while a second offsettable component 805 is constrained to travel with the first component along the first dimension of travel. The depicted assembly has two transducer sets, including set 807, which may be considered to have transducers that displace the second component relative to the first component along the "x" axis, similar to how described in connection with the gripper embodiment discussed above, and a second set 809, which may be considered to have transducers that displace the second component relative to the first component along the "z" axis to adjust fly height. In this example, the second transducer set is considered to have three transducers and associated contact points c1-c3 to optionally enable automatic planar equalization of the second component 805 along the "z" axis (i.e., to accommodate unintentional tilt of the second component in the x-z and y-z planes). As represented by numeral 805' and broken linkage 806, the second component can optionally be structured as two or more components, e.g., offsettable from each other along the "z" axis and offset as a group from the first component along the "x" axis. Each transducer set is considered to include a mechanical linkage / support structure (labeled "M" in the figure), such as the floating pivot plate assembly or structural support analogue described above, to structurally constrain components 803 and 805 to move together along the "y" axis while allowing offsettable component 805 to advance in the x and z dimensions relative to first component 803.

[0141] FIG. 8B is a cross-sectional view of another assembly 831 that uses two different sets of transducers "T" to correct for errors in more than one dimension. In this illustration, a first component is represented by numeral 833, while a second offsettable component is represented by numeral 835. These components are also constrained to travel together along the "y" axis, while in this example, selectively offsettable from one another in the direction of arrow 836 (i.e., along the "x" axis). In one embodiment, these components are structurally similar to the gripper design of FIG. 6B, with a set of transducers used to achieve displacement in the direction of arrow 836; the mechanical linkage between components 833 and 835 is not visible in the illustration.

[0142] To correct for fly-height in this example, second component 835 again supports vacuum chuck 839, represented by dashed line 845, used to engage the substrate. One or more transducers 837 are used to selectively displace vacuum chuck 839 along the “z” axis in the direction of arrow 841. In this case, vacuum chuck 839 is also supported by flexures 843, which provide a spring force that allows for a slight negative “z” axis displacement of vacuum chuck 839 and substrate 845 when no force is exerted by one or more transducers 839, but also provide sufficient spring force to allow for a slight positive “z” axis displacement of vacuum chuck 839 and substrate 845 when the transducers are actuated to their full throw. Depending on the embodiment, the transducers can be piezoelectric transducers when the required throw is less than about 3 microns, while voice coil or similar transducers can be used for larger throws, e.g., 5 microns or more. Other types of actuator scans can also be used depending on the embodiment.

[0143] In this example, flexures are used to provide structural support that, along with a floating pivot assembly (e.g., as seen in FIG. 6D), constrains the two components to travel together along the "y" axis, although other types of structures that perform these functions will no doubt occur to those skilled in the art. The examples presented above are, as a result, to be considered merely illustrative, and not limiting.

[0144] VI. Conclusion Considering the various techniques and considerations introduced above, manufacturing processes can be implemented to rapidly mass-produce products at low per-unit costs. When applied to display device or solar panel manufacturing, e.g., flat panel displays, these techniques enable high-speed, panel-by-panel printing processes, optionally with multiple panels produced from a common substrate. By providing high-speed, repeatable, error-free printing techniques (e.g., using common inks and printheads for each panel), it is believed that printing can be substantially improved, e.g., reducing printing time per layer to a small fraction of the time that would be required without the techniques, while ensuring consistent, precise ink deposition within the desired target area of ​​each substrate. Returning again to the example of a large HD television display, it is believed that each color component layer can be accurately and reliably printed for large substrates (e.g., 8.5 generation substrates measuring approximately 220 cm × 250 cm) in 180 seconds or less, or even 90 seconds or less, representing a substantial process improvement. Improving printing efficiency and quality paves the way for significant reductions in the cost of producing large HD television displays and, therefore, lower end-user costs. As mentioned above, display manufacturing (and specifically OLED manufacturing) is one application of the techniques introduced herein, but these techniques can be applied to a wide variety of processes, computers, printers, software, manufacturing equipment, and end devices, and are not limited to display panels. In particular, it is anticipated that the disclosed techniques can be applied to any process in which a printer is used to deposit multiple product layers as part of a common printing operation, including, but not limited to, many microelectronic applications.

[0145] It should be noted that the described technique offers numerous options. In one embodiment, panel (or product-by-product) misalignment or skew can be adjusted on a product-by-product basis within a single array or on a single substrate. The printer scan path can be planned so that misorientation of the substrate (or other transported item, such as a printhead) is automatically compensated for via transducers coupling the substrate and the transport system (e.g., grippers) without requiring adjustment / adaptation based on one or more alignment errors. In one embodiment, transducer corrections can be used to mitigate errors within different transport paths (e.g., printhead transport paths), or multiple transducers or transducer sets can be used to correct multi-dimensional position and / or orientation errors. In various embodiments, as described, errors are not pre-measured, but rather are dynamically detected and used to fine-tune the substrate and / or individual panel position to provide perfect alignment. will be done.

[0146] Also, while various embodiments illustrate the use of a gripper (or mechanism coupling the substrate to the transport mechanism) and the use of two transducers to achieve fine adjustment, other embodiments may use a different number of these elements. For example, in one embodiment, two or more grippers, each with its own dedicated transducer, may be used. Additionally, while the techniques described above are illustrated as applied to a printer using a vacuum gripper system, many other applications may benefit from the described techniques, including applications using different types of transport mechanisms, different types of printers, different types of deposition mechanisms, or other types of transport paths or mechanisms. Clearly, many variations exist without departing from the inventive principles described herein.

[0147] In the foregoing description and accompanying drawings, specific terminology and drawing symbols are set forth to provide a thorough understanding of the disclosed embodiments. In some cases, the terminology and symbols may imply specific details that are not required to practice these embodiments. The terms "exemplary" and "embodiment" are used to express examples, rather than preferences or requirements.

[0148] As shown, various modifications and changes may be made to the embodiments presented herein without departing from the broader spirit and scope of the present disclosure. For example, a feature or aspect of any of the embodiments may be applied in combination with any other of the embodiments, or in place of a corresponding feature or aspect, at least where practical. Thus, for example, not all features are shown in each and every drawing, and it is contemplated that a feature or technique shown according to an embodiment of one drawing can be optionally employed as an element of, or in combination with, a feature of, any other drawing or embodiment, even if not specifically declared herein. Thus, the present specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The present invention provides, for example, the following. (Item 1) 1. An apparatus for processing layers of an electronic product, comprising: a printhead for depositing material onto a substrate, said material forming said layer; a transport system that transports at least one of the substrate and the print head during deposition of the material; a component of the conveying system advanced along a transport path; an optical system comprising a light beam directed parallel to the transport path and a detector that detects the light beam, the optical system configured such that deviations of the component in at least one dimension independent of a direction of the light beam are detected by the detector; at least one transducer actuated to displace the component in a direction perpendicular to the transport path in response to the deviation; An apparatus comprising: (Item 2) 2. The apparatus of claim 1, wherein the advancement of the component is characterized by mechanical imperfections that generate at least one of a translation error and a rotation error that affects the deposition of the material on the substrate, and the at least one is actuated to equalize the at least one error. (Item 3) The component transports the print head, and the at least one converter adjusts the print head in response to the deviation so that the print head travels parallel to the light beam. Item 1. The device according to item 1, which is driven. (Item 4) Item 1, an apparatus according to item 1, wherein the component is part of a gripper system that transports the substrate along the transport path, and the at least one transducer is driven in response to the deviation so that the substrate travels parallel to the light beam. (Item 5) the conveying system is a first conveying system, the transport path is a first transport path, the optical system is a first optical system, the component is a first component, and the at least one transducer is part of a first transducer set; The apparatus also includes: a second transport system for transporting a second component along a second transport path, the second component carrying the print head; and a second optical system comprising a second light beam directed parallel to the second transport path and a second detector that detects the second light beam, the second optical system configured such that deviations of the print head in at least one dimension independent of a direction of the second light beam are detected by the second detector; a second transducer set comprising at least one transducer operatively coupling the second transport path and the print head, the second transducer set being driven in response to the deviation of the print head in the at least one dimension independent of the direction of the second light beam; Item 5. The device according to item 4, comprising: (Item 6) the detector is configured to detect a deviation of the component in at least two degrees of freedom independent of the direction of the light beam; Item 1, wherein the at least one transducer comprises at least two transducer sets, each transducer set being driven in response to a deviation of the component in a corresponding one of the at least two degrees of freedom so as to equalize the deviation in the corresponding one. (Item 7) 3. The apparatus of claim 2, wherein the detector comprises a four-cell sensor and the at least two degrees of freedom comprise movement in two independent dimensions, each orthogonal to the direction of the light beam. (Item 8) Item 10. The apparatus of item 1, wherein the detector comprises at least two sensors, each of the at least two sensors detecting a deviation of the component in a common dimension independent of the direction of the light beam, and the at least two sensors configured to detect a rotation of the component relative to the direction of the light beam responsive to a difference between the deviations detected by each of the at least two sensors along the common dimension. (Item 9) Item 10. The apparatus of item 1, wherein the component comprises a vacuum gripper that selectively engages the substrate using a vacuum, the vacuum gripper transporting the substrate along the transport path. (Item 10) Item 10. The apparatus of item 1, wherein the optical system comprises a laser source, the light beam comprises a laser beam, and the component mounts at least one of the laser source, the detector, and beam redirecting optics in a manner such that movement of the component in a direction orthogonal to the direction of the light beam is detected by the detector. (Item 11) the transport system is a first transport system that transports the substrate; the transportation path is a first transportation path, and the optical system is a first optical system; The apparatus also includes: a second component associated with the second transport system that transports the print head along a second transport path during deposition of the material; and a second optical system comprising a second light beam directed parallel to the second transport path and a second detector that detects the second light beam, the second optical system configured such that deviations of the second component in at least one dimension independent of a direction of the second light beam are detected by the second detector; means for identifying non-orthogonality between the first transportation path and the second transportation path; Item 1. The device according to item 1, comprising: (Item 12) Item 10. The apparatus of claim 1, wherein the at least one converter comprises at least three converters operatively coupling the transport path and the component, the at least three converters being driven in response to the deviation so as to equalize it as the component is advanced along the transport path. (Item 13) Item 10. The apparatus of claim 1, wherein the at least one transducer comprises at least two transducers, each transducer selectively displacing the component in a common direction orthogonal to the direction of the light beam, the at least two transducers being driven in a common mode to displace the component in the common direction, and the at least two transducers being driven in a differential mode to rotate the component relative to the common direction. (Item 14) Item 14. The apparatus of item 13, wherein each transducer of the at least one transducer comprises at least one of a voice coil, a linear actuator, and a piezoelectric transducer. (Item 15) the component is a second component, the conveying system includes a gripper, the gripper including a first component constrained to travel along the transport path and the second component; Item 14. The apparatus of item 13, wherein the gripper also includes a mechanical structure operably coupling the first component with the second component, the mechanical structure constraining the second component to travel with the first component along the transport path while allowing the at least one transducer to displace the second component from the first component in the at least one dimension to equalize the deviation. (Item 16) Item 16. The apparatus of item 15, wherein the at least one transducer comprises at least two transducers each selectively displacing the component in a common direction orthogonal to the direction of the light beam, the mechanical structure configured to provide a mechanical pivot point that is similarly displaced in the common direction in response to actuation of the at least two transducers, the at least two transducers being driven in a common mode to displace the component in the common direction and in a differential mode to rotate the component relative to the common direction. (Item 17) Item 10. The apparatus of item 1, further comprising means for adjusting the direction of the light beam relative to the transport path. (Item 18) Item 10. The apparatus of item 1, further comprising means for detecting angular misalignment between the light beam and the transport path. (Item 19) 1. A method for depositing materials and processing layers in an electronic product, said method comprising: depositing droplets of the material onto a substrate using a print head; The material forms the layer; and transporting at least one of the substrate and the print head during deposition of the material using a transport system; advancing a component of the conveyance system along a transport path; directing a light beam parallel to the transport path and detecting the light beam using a detector in a manner to detect deviations of the component in at least one dimension independent of the direction of the light beam; driving at least one transducer to displace the component in a direction perpendicular to the transport path in response to the deviation; A method comprising: (Item 20) 1. An apparatus for depositing materials and processing layers of an electronic product, said apparatus comprising: means for depositing droplets of said material onto a substrate using a printhead, said material forming said layer; and means for transporting at least one of the substrate and the print head during deposition of the material, the means for transporting comprising a component that is advanced along a transport path; and a light beam directed parallel to the transport path; means for detecting deviation of the component in at least one dimension independent of the direction of the light beam using a detector configured to detect the light beam; means for driving at least one transducer to displace the component in a direction perpendicular to the transport path in response to the deviation; An apparatus comprising: Many uses, substitutions, modifications, and improvements are possible.

Claims

1. A printing device comprising:

1. A conveying system, comprising: a first component that moves the object along a transportation path; a second component for moving the object in a direction perpendicular to the transportation path; A light source and an optical detector mounted on the second component and configured to detect light directed by the light source; and A printing apparatus comprising: a controller operably coupled to the optical detector and the second component, and configured to control movement of the second component in a direction perpendicular to the transport path in response to a signal from the optical detector.

2. 10. The printing apparatus of claim 1, wherein the transport system is part of an inkjet printer and the object is a printhead or a substrate.

3. 2. The printing device according to claim 1, wherein the light source is a laser.

4. The printing device of claim 1 , wherein the second component further comprises a linear transducer that moves the second component.

5. 2. The printing device of claim 1, wherein the second component further comprises a linear transducer that moves the second component, and the controller controls the movement of the second component by controlling the linear transducer.

6. The printing apparatus of claim 3 , further comprising an adjustment mechanism for adjusting a direction of the laser coupled to the laser.

7. The printing device of claim 1 , wherein the first component and the second component are components of a gripper.

8. 10. The printing apparatus of claim 1, wherein the optical detector comprises at least two optical sensors.

9. The printing apparatus of claim 8 , wherein the optical detector further comprises a beam splitter.

10. 2. The printing apparatus of claim 1, wherein the first component comprises a vacuum gripper, the second component comprises a voice coil, the light source comprises a laser, and the optical detector comprises at least two sensors and a beam splitter.

11. the conveying system is a first conveying system, the object is a first object, the transportation path is a first transportation path, the light source is a first light source, and the photodetector is a first photodetector; Further, a second conveying system is provided, the second conveying system comprising: a third component that moves the second object along the second transportation path; a fourth component that moves the second object in a direction perpendicular to the second transportation path; a second light source; a second optical detector mounted to the fourth component and configured to detect light directed by the second light source; the controller is operably coupled to the second optical detector and the fourth component and configured to control movement of the fourth component in a direction perpendicular to the second transport path in response to a signal from the second optical detector. The printing device according to claim 1.

12. The printing apparatus of claim 11 , wherein the first object is a substrate gripper and the second object is a print head.

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