KR20190138705A - Techniques for print ink droplet measurement and control to deposit fluids within precise tolerances - Google Patents

Abstract

The ink printing process uses processing software to plan droplet volume measurement and droplet combination per nozzle, to ensure that a certain cumulative ink fill per target area is reached and conforms to the minimum and maximum ink fill set by the specification. In various embodiments, various droplet combinations are generated through various printhead / substrate scan offsets, offsets between printheads, the use of various nozzle drive waveforms, and / or other techniques. These combinations can be based on repeated, rapid droplet measurements that grow the comprehension for each nozzle of the mean and spread for the expected droplet volume, velocity, and trajectory, with a combination of droplets planned based on these statistical parameters. . Optionally, random charging variations can be introduced to mitigate the Mura effect in the finished display device. The disclosed technique has as many applications as possible.

Description

TECHNIQUES FOR PRINT INK DROPLET MEASUREMENT AND CONTROL TO DEPOSIT FLUIDS WITHIN PRECISE TOLERANCES}

Cross-Reference to Related Applications

This application is directed to US Provisional Patent Application No. 61 / 950,820 for "Techniques For Print Ink Droplet Volume Measurement And Control Over Deposited Fluids Within Precise Tolerances," filed March 10, 2014, on behalf of the first inventor Nahid Harjee. Insist on priority. This application is also part of US Utility Model Application No. 14/162525 for "Techniques for Print Ink Volume Control To Deposit Fluids Within Precise Tolerances," filed on January 23, 2014, on behalf of the first inventor Nahid Harjee. Is a pending application. U.S. Utility Model Patent Application No. 14/162525 is a Taiwan patent application No. 102148330 for "Techniques for Print Ink Volume Control To Deposit Fluids Within Precise Tolerances" filed December 26, 2013, which was represented by first inventor Nahid Harjee. PCT Patent Application No. PCT / US2013 for "Techniques for Print Ink Volume Control To Deposit Fluids Within Precise Tolerances" filed December 24, 2013, which claims priority to No. 1 and is represented by first inventor Nahid Harjee. / 077720 is a continuing application. PCT Patent Application No. PCT / US2013 / 077720 claims priority to each of the following patent applications: US Provisional Patent Application No. 61 / 746,545, “Smart Mixing”, first inventor Conor Francis Madigan, filed December 2012 27 days; US Provisional Patent Application No. 61/822855 “Systems And Methods Providing Uniform Printing of OLED Panels”, first inventor Nahid Harjee, filed May 13, 2013; US Provisional Patent Application No. 61/842351, "Systems And Methods Providing Uniform Printing of OLED Panels", first inventor Nahid Harjee, filed: 07/02/2013; US Provisional Patent Application No. 61/857298 "Systems And Methods Providing Uniform Printing of OLED Panels", first inventor Nahid Harjee, filed July 23, 2013; United States Provisional Patent Application No. 61/898769 “Systems And Methods Providing Uniform Printing of OLED Panels”, first inventor Nahid Harjee, filed November 01, 2013; And US Provisional Patent Application No. 61 / 920,715, "Techniques for Print Ink Volume Control To Deposit Fluids Within Precise Tolerances", first inventor Nahid Harjee, filed December 24, 2013. In addition, this application is a U.S. provisional patent for "OLED Printing Systems and Methods Using Laser Light Scattering for Measuring Ink Drop Size, Velocity and Trajectory" filed on April 26, 2014, which was represented by the first inventor Alexander Sou-Kang Ko. Regarding "OLED Printing Systems and Methods Using Laser Light Scattering for Measuring Ink Drop Size, Velocity and Trajectory" filed on August 14, 2013, representing Application No. 61/816696 and the first inventor Alexander Sou-Kang Ko Claims priority of US provisional patent application No. 61/866031. Each of these patent applications is incorporated herein by reference.

The present application provides a technique for measuring the volume of inkjet droplets used in the manufacture of organic light emitting diode ("OLED") devices with a high statistical accuracy and the use of a printing process to transfer droplets of fluid ink to a target area of a substrate at an accurate cumulative amount; It relates to methods, devices, improvements and systems in this regard. In one non-limiting application, the techniques provided herein can be applied to manufacturing processes for OLED display panels.

In a printing process in which the printhead has a plurality of nozzles, not all nozzles respond to the standard drive waveform in the same way, that is, each nozzle may produce slightly different volumes of droplets. In situations where nozzles are used to deposit fluid droplets into their respective fluid deposition regions (“target regions”), problems may arise if there is no consistency. This is a particular problem when manufacturing applications in which ink transfers material that will become a permanent thin film structure in an electronic device. One example application in which this problem arises is the use of displays such as organic light emitting diode (“OLED”) displays, which are used for large and small electronic devices (eg, portable devices, mass high definition television panels and other devices). It is a manufacturing process applied to the clan. Printing processes are used to deposit inks carrying the luminescent material of such displays, and volume mismatches across rows or columns of pixels cause visible light or color defects in the displayed image. As used herein, “ink” means any fluid applied to a substrate by a nozzle of a printhead regardless of its color properties, such as in the aforementioned OLED display manufacturing applications, directly forming a layer of permanent material. In order to do this, the ink is generally deposited in place, and then processed, dried or cured, and it should be noted that this process can be repeated with the same ink or with different inks to form these various layers. .

1A introduces a nozzle-droplet mismatch problem, wherein the diagram shown is referred to entirely by numeral 101. In FIG. 1A, the printhead 103 is shown having five ink nozzles, each nozzle being shown with a small triangle at the bottom of the printhead, each numbered respectively by (1)-(5). . Note that in a typical manufacturing application, depending on the application, there may be more than five nozzles, such as 24-10,000, and in the case of FIG. 1A, five nozzles are simply referenced for ease of understanding. In an exemplary application, it is desirable to deposit 50 picoliters (50.00 pL) of fluid into each of the five specific target regions of the array of such regions, and further, each of the five nozzles of the printhead is 10 picoliters (10.00). The fluid of pL must be ejected into each of the various target areas by relative motion between the printhead and the substrate (“pass” or “scan”). The target region may be any surface region of the substrate, such as unseparated regions that are in contact with each other (eg, such that the deposited fluid ink is partially diffused and mixed together between the regions), or respectively, flow isolated regions. These regions are generally represented using ellipses 104-108 in FIG. 1A, respectively. Thus, it may be assumed that exactly five passes of the printhead are required to fill each of the five specific target regions as shown. In practice, however, printhead nozzles may have minor variations in structure or operation such that a particular drive waveform applied to each nozzle transducer may produce slightly different droplet volumes for each nozzle. As shown in FIG. 1A, for example, injection of nozzle 1 produces a droplet of 9.80 picoliters (pL) volume by each pass, with five 9.80 pL droplets shown in ellipse 104. do. Although each of the droplets appears as discrete locations in the target area 104 in the figure, in practice, the locations of each of the droplets may be the same or overlap. In contrast, the nozzles 2-5 produce droplet volumes of 10.01 pL, 9.89 pL, 9.96 pL and 10.03 pL, respectively, slightly different. By five passes between the printhead and the substrate where each nozzle deposits fluid into the target region 104-18 in a mutually exclusive manner, the deposition is 1.15 pL of cumulative deposited ink volume over the five target regions. Deviations will be derived, which may not be acceptable in many applications. For example, in some applications, a difference of 1 percent (or even lower percentage) in the deposited fluid can cause problems and in the case of OLED display illumination, such deviations can be observed in the finished display. It can potentially cause artifacts.

Thus, television and other forms of display manufacturers will effectively specify the precise volume ranges, such as 50.00 pL, ± 0.25 pL, that must be observed with high precision so that the end product can be tolerated, and in this exemplary case, the specified tolerances Tolerance must be within one-half percent of the target of 50.00 pL. In one application where each nozzle represented by FIG. 1A is deposited with pixels of each horizontal line of a high definition television (“HDTV”) screen, the shown deviation of 49.02 pL-50.17 pL is therefore unacceptable. The quantity can be calculated because it will exhibit about ± 1.2% deviation (eg, instead of the desired maximum tolerance of ± 0.5% deviation). Although the display technique is mentioned as an example, it should be understood that in another context a nozzle-droplet mismatch problem may occur.

In FIG. 1A, the nozzles are specifically aligned with the target area (eg, well) such that a particular nozzle is printed to a particular target area. In FIG. 1B, an alternative case 151 is shown where the nozzles are not specifically aligned and the nozzle density is high relative to the target area density, in which case any nozzle that would cross a particular target area during a scan or pass is shown. It is used to print into, with the possibility that several nozzles in each pass traverse each target area. In the example shown, the printhead 153 appears to have five ink nozzles and the substrate appears to have two target areas 154-155, each of which has nozzles 1 and 2 The target area 154 is traversed, the nozzles 4 and 5 traverse the target area 155, and the nozzle 30 is positioned so as not to traverse any target area. As shown, in each pass, one or two droplets are deposited into each well. In other words, the droplets can overlap or deposit at discrete points within each target region, and the particular illustration of FIG. 1B is merely illustrative and, as shown in FIG. 1A, a 50 picoliter (50.00 pL) fluid is used. It is desirable to deposit into each target region 154-155, with each nozzle having a nominal droplet volume of approximately 10.00 pL. Using the same volume deviation per nozzle droplet as observed in connection with the example of FIG. 1A, each nozzle overlapping the target region on a particular pass will deliver the droplet into the target region until a total of five droplets have been delivered. Is assumed, it is observed that in three passes the target area is filled and there is a total deposited ink volume deviation of 0.58 pL from the target of 50.00 pL between the two target areas, moreover, a mismatch other than the specified tolerance, which is, Again, this is not acceptable in many applications.

In connection with the above example, it is noted that the droplet matching problem is further exacerbated by the problem that the droplet volume can vary statistically even for a given nozzle and a given drive waveform. Thus, in the example discussed above, the nozzle 10 of the printhead from FIGS. 1A and 1B will produce a droplet volume of 9.80 pL in response to a given drive waveform, but in practice, the droplet volume may vary. It can be assumed that it will vary somewhat depending on factors such as process, voltage, temperature, printhead age, and many other factors, so that the actual droplet volume will not be accurately known.

Generally speaking, techniques are proposed to solve the droplet matching problem, but none of these techniques are still reliable, providing a fill factor that is within the desired tolerance range or dramatically increasing manufacturing time and cost. That is, it does not meet the goal of having high quality at low consumer cost points, which quality and low cost points may be essential in applications where industrial products, such as HDTV, are involved.

Thus, there is a need for techniques useful for depositing fluid into target areas of a substrate using a printhead with a nozzle. More specifically, despite the variation in nozzle-droplet ejection volume, the fluid volume deposited at each target region of the substrate, ideally allowing for high speed fluid deposition operations and thus improving the speed of device fabrication. There is a need for a technique for precise control. The techniques described below meet these needs and further provide related advantages.

FIG. 1A is a diagram presenting a hypothetical problem of depositing ink in a target area of a substrate where a printhead with five nozzles is used to deposit a target fill amount of 50.00 pL in each of five specific target areas.
FIG. 1B is another diagram illustrating the hypothetical problem of depositing ink in a target region of a substrate where a printhead with five nozzles is used to deposit a target fill amount of 50.00 pL in each of two specific target regions.
2A is an illustrative diagram showing a droplet measurement system capable of measuring droplet volume for each nozzle of a bulk printhead assembly.
2B is a method diagram illustrating various processes and options related to the measurement of droplets for each nozzle.
2C is a method diagram showing various processes and options related to the measurement of the droplet volume for each nozzle to achieve high-reliability understanding of the expected droplet volume.
2D is a schematic diagram showing the layout of various configurations used in one embodiment to perform droplet measurement.
2E is a schematic diagram showing the layout of various configurations used in another embodiment to perform droplet measurement.
3A provides a descriptive view showing a series of optional steps, products or services that can independently implement the techniques introduced previously.
3B is a diagram illustrating a hypothetical arrangement of a printer and a substrate in an application where the substrate will ultimately form a display panel with pixels.
3C is a cross-sectional close-up view of the printhead and substrate of FIG. 3B taken from the perspective view of line CC of FIG. 3B.
FIG. 4A is a view similar to FIG. 1A showing the use of a combination of droplet volumes to reliably produce ink fill volume for each target region within a specified tolerance range, wherein in one optional embodiment, the designated nozzle Different droplet volume combinations are generated from a set of jetting waveforms, and in yet another alternative embodiment, different droplet volume combinations are created from respective nozzles of the printhead using relative movement 405 between the printhead and the substrate.
4B is a diagram used to illustrate the ejection of relative printhead / substrate motion and different droplet volume combinations to respective target regions of the substrate.
4C is a diagram used to illustrate the use of different nozzle drive waveforms at each nozzle to produce different droplet volume combinations into respective target regions of the substrate.
FIG. 4D is a diagram similar to that of FIG. 1B except for the use of a combination of droplet volumes to reliably produce ink fill volume for each target region within a specified tolerance range, and in one optional embodiment, FIG. Different droplet volume combinations are generated from a set of nozzle ejection waveforms, and in yet another alternative embodiment, different droplet volume combinations are generated from respective nozzles of the printhead using relative motion 472 between the printhead and the substrate.
FIG. 5 is a block diagram illustrating a method of planning a combination of droplets for each target region of a substrate, which method may be applied to any optional embodiment introduced by FIGS. 4A-D.
6A provides a block diagram for selecting a particular set of acceptable droplet combinations for each target region of a substrate usable with any of the embodiments introduced above.
6B is a block diagram for iteratively planning printhead / substrate motion and using nozzles based on a combination of droplets for each print area.
6C provides a block diagram illustrating the further optimization of the printhead / substrate motion and the use of nozzles to command the scan so that printing can be performed as efficiently as possible.
FIG. 6D is a hypothetical top view of a substrate on which to produce a plurality of flat panel display devices (eg, 683), and as indicated by region 687, printhead / substrate motion is optimized for a particular area of a single flat panel display device. Where optimization is used repeatedly or periodically across each display device (eg, four illustrated flat panel display devices).
FIG. 7 provides a block diagram for intentionally changing the fill volume within tolerances allowed to reduce visible artifacts in the display device.
FIG. 8A provides a block diagram illustrating how droplet measurement is used to accommodate statistical variations in droplet volume per nozzle and per drive waveform, and how to allow precise cumulative ink filling within a given target area.
FIG. 8B provides a block diagram illustrating how droplet measurements are planned and how to allow precise cumulative ink filling within a given target area to accommodate statistical variations in droplet volume per nozzle and per drive waveform.
9A provides a graph showing the variation in target area fill volume when there is no adjustment for droplet volume variation between nozzles of the printhead.
9B provides a graph showing the variation in target area fill volume where different nozzles are randomly used to statistically compensate for droplet volume variation between nozzles of the printhead.
FIG. 9C provides a graph showing the variation of the target area fill volume that is used to achieve the target area fill volume in close tolerance as planned, with one or more droplets of different volumes.
FIG. 10A provides a graph showing the variation in target area fill volume, without adjusting for nozzle-to-nozzle droplet volume variation of the printhead.
FIG. 10B provides a graph showing the variation in target area fill volume where different nozzles are optionally used to statistically compensate for nozzle-to-nozzle droplet volume variations of the printhead.
10C provides a graph showing the variation in the target area fill volume used to achieve the target area fill volume within close tolerances on a planned basis with one or more different volumes of droplets.
11 shows a top view of a printing press used as part of the manufacturing apparatus, which may be in a gas enclosure allowing printing to occur in a controlled atmosphere.
12 provides a block diagram of a printing press, which may optionally be used, for example, in the manufacturing apparatus shown in FIG.
13A shows one embodiment where a plurality of printheads (each with nozzles) are used to deposit ink on a substrate.
13B shows the rotation of the plurality of printheads to better align the nozzles of the respective printheads with the substrate.
FIG. 13C illustrates the offsets of the individual printheads of the plurality of printheads associated with intelligent scanning to intentionally create a particular droplet volume combination.
13D is a cross sectional view of a substrate including a layer that can be used in an organic light emitting diode (OLED) display.
14A illustrates different ways of customizing or changing the nozzle injection waveform.
14B shows a way of defining a waveform according to a discrete waveform segment.
15A illustrates one embodiment in which different droplet volume combinations can be obtained using different combinations of designated nozzle injection waveforms.
FIG. 15B illustrates circuitry associated with generating and applying a programmed waveform at a time (or location) programmed at the nozzle of the printhead, which circuits 1523/1531, 1524/1532, and 1525/1533, respectively, of FIG. 15A. One possible implementation of is provided.
15C shows a flow diagram of one embodiment using different nozzle spray waveforms.
15D shows a flowchart associated with a nozzle or nozzle-waveform qualification.
16 shows a perspective view of an industrial printing press.
17 shows another perspective view of an industrial printing press.
18A presents a schematic diagram illustrating the layout of a configuration in an embodiment of a shadow-based droplet measurement system.
18B presents a schematic diagram showing the layout of the configuration in an interferometry-based embodiment.
FIG. 19 shows a flow diagram related to one illustrative process incorporating a droplet measurement system and optionally an industrial printing press used for OLED device fabrication.
The invention defined by the claims can be better understood by reference to the following detailed description, which is to be read in connection with the appended drawings. This description of one or more specific embodiments provided below to build and use various embodiments of the techniques provided by the claims is intended to illustrate the application rather than to limit the claims. Non-limitingly, the present specification provides a layer of material by planning printhead motion to keep the deposited ink volume within specified tolerances without excessively increasing the number of printhead passes (and thus the time required to complete the deposited layer). Some different examples of the techniques used to prepare them are provided. In connection with these techniques, accurate droplet measurement can be performed to accurately design synthetic inks within any target area with measurements that are highly integrated with product printing. Various techniques may be employed as deposition means in the form of software for performing these techniques, computers in which such software is run, printers or other devices, in the form of control data (eg, printed images) for forming a layer of material, Or as an electronic or other device (eg, flat panel device or other consumer end product) manufactured as a result of these techniques. While specific examples are shown, the principles described herein may be applied to other methods, devices, and systems.

DETAILED DESCRIPTION This disclosure relates to the use of a printing process to transfer layer material to a substrate, techniques for droplet measurement with high precision, and related methods, improvements, devices, and systems.

The nozzle consistency problem introduced above can be solved by measuring the droplet volume per nozzle (or droplet volume deviation between nozzles) of the printhead against the firing waveform of a particular nozzle. This makes it possible to plan printhead spray patterns and / or motion for depositing a precise total fill volume of ink into each target area. Understanding what is the difference in droplet volume between nozzles, the printhead / substrate position offset and / or in a manner that accommodates the difference in droplet volume but still optimizes simultaneous printing to adjacent target areas in each pass or scan. Droplet spray patterns can be planned. In different respects, instead of normalizing or averaging droplet volume deviations between nozzles, specific droplets of each nozzle in a planned manner to simultaneously obtain in-range cumulative volumes for multiple target regions of the substrate. Volume characteristics are measured and used, and in many embodiments, this planning is performed using a process that reduces the number of scan or printhead passes in accordance with one or more optimization criteria.

A number of different embodiments will be presented below, which contribute to achieving the following results. It is also expressly contemplated that each embodiment may be used separately, or that the features of any embodiment may be used mixed and matched with the features and options of the various embodiments.

One embodiment presents a system and technique for providing an individualized droplet measurement device on a very large printhead assembly (eg, having hundreds to thousands or more of nozzles). The logical difficulties associated with positioning the optics are solved using a bottom-deposition-plane-measuring technique (ie, by redirecting light away from the vicinity of the printhead beyond the relative distance at which the substrate is normally positioned for deposition). For example, using an optical assembly that can operate in three dimensions, a large printhead assembly (eg, within a confinement space) may optionally be stopped (eg, at a printer service station), and the droplet measurement device may be a large printhead. It is correctly connected to the assembly. Determination of the droplet volume of a tight nozzle array at the required distance from the nozzle plate (printhead assembly typically operates at approximately 1 millimeter from the substrate surface), despite the confinement space, due to the exact location of the under-deposition-planar optical assembly This is possible. In one alternative embodiment, the optical system uses shadow plots and repeated measurements of droplets emanating from certain nozzles (and optionally variable nozzle drive waveforms) to increase the statistical confidence of the expected droplet volume. In another alternative embodiment, the optical system uses interferometry and repeated measurements of liquid crystals emanating from certain nozzles (and optionally variable nozzle drive waveforms) to increase the statistical reliability of the expected droplet volume.

In production lines, it is typically desirable to have as little downtime in production as possible to maximize productivity and minimize manufacturing costs. Therefore, in another alternative embodiment, the droplet measurement time is "hide" or "stack" after another line process. For example, in an optional flat panel display fabrication production line, as each new substrate is loaded, or otherwise handled, processed, or transported, the printhead assembly of the printing press is analyzed using a droplet measurement process, thereby per-nozzle (and / or Or per nozzle, per drive waveform) to enable accurate statistical understanding of the droplet volume. For printhead assemblies with tens of thousands of nozzles, repeated droplet measurements (eg, if multiple drive waveforms are used, measuring dozens of droplets per nozzle, per drive waveform, if multiple drive waveforms are used) can take considerable time and provide optional system control. The process and associated software can thus perform droplet measurements on a dynamic, incremental basis. For example, if a fictitious load / unload process is required, for example 30 seconds, and each print process is 90 seconds, then the printhead assembly can be measured during the load / unload process in a two minute cycle, updating the droplet measurement to Using the sliding window of the nozzles / droplets analyzed during the load / unload process associated with the 2-minute cycle, droplet volume averages and confidence intervals per nozzle can be obtained. Many other processes are possible, and continuous and dynamic processes are not required for all embodiments. In practice, however, the droplet volume and drive waveform for a given nozzle will vary for different nozzles and drive waveforms, and also typical values are due to factors such as ink characteristics, nozzle age and degradation and subtle deviations from other factors. Will change over time. Thus, for example, a process that periodically updates from hours to days may be desirable to further improve reliability.

In another alternative embodiment, the droplet measurement system uses interferometry and non-imaging techniques, such as performing per liquid crystal measurement in microseconds, and repeating across a printhead assembly with thousands of nozzles in less than 30 minutes. Get very fast droplet measurement. Compared with imaging techniques (using cameras and captured image pixel processing techniques to obtain volume measurements), interferometry techniques provide accurate droplet volume by correlating these distances with multiple light sensors, representative droplet shapes and droplet volumes. Measurement can be provided. In one embodiment, the laser source and / or associated optics and / or sensors are mechanically mounted for bottom deposition plane measurements and effectively connected to large printhead assemblies. Because very fast measurements are obtained with such a system, interference measurement techniques are particularly useful in embodiments that perform dynamic, incremental measurements, as just described, and with this technique, thousands of nozzles are dropped in each print cycle. The measurement is repeated (eg, measuring 30 droplets per nozzle) to achieve high statistical confidence for each expected droplet volume.

In another alternative embodiment, many droplet measurements are taken for per nozzle and per nozzle drive waveforms (for embodiments that use variable nozzle drive waveforms). As the number of measurements increases, the mean and standard deviation (assuming normal random distribution) for each nozzle-waveform combination becomes more robust. Using a mathematical process executed by software, statistical models for each droplet can be generated and combined accurately to develop a statistical model for synthetic ink filling per target area. To provide an illustration, many measurements are taken for each nozzle and for each drive waveform. If a single measurement of the droplet volume is expected to be accurate to 2 percent of standard deviation, then many measurements are made to obtain a statistically accurate mean with a reduced variance or standard deviation, i.e. assuming a normal random distribution, the standard deviation is Decreased by the number n of measurements according to sigma / (n) ^1/2 , four measurements of the droplet volume will reduce the standard deviation by half. Thus, in one embodiment, software is used to achieve a much higher confidence interval around the expected droplet volume through specially planned and repeated measurements, which helps to substantially reduce the measurement error. Many different statistical measurements are used, for example, if a synthetic fill is expected to be in the range of ± x% (e.g., ± 0.5% of the target fill), droplet measurement is performed for each nozzle and for each of the various drive waveforms. , 3σ (99.73%) confidence interval is obtained near the expected droplet volume within the same range of mean droplet volume (eg, ± 0.5%). In other words, using accurate statistical models formed for each of the various droplets, known techniques are used to plan the droplet combinations based on mathematical combinations of the relevant statistical models, resulting in high accuracy near ink filling per cumulative target area. (In spite of droplet volume variations between nozzles or between waveforms). While a normal random distribution is used to select an embodiment, any statistical model can be used (e.g., T's of a species, Student's), where the individual distributions are combined (e.g. by software) to combine various droplets. A cumulative distribution can be obtained. Also, in some embodiments, 3σ (99.73%) measurements are used, while in other embodiments, other types of statistical measurements are used, such as 4σ, 5σ or 6σ or measurements not explicitly related to the random distribution.

Similar techniques can be applied to develop a model of droplet volume and flight trajectory for each nozzle-waveform combination. These variations may be further applied to other alternative embodiments.

The substitutions or subsets of the techniques and embodiments described above can be applied to accurately plan for cumulative ink filling in the target area, that is to say for a specific composite volume based on droplet volume variation per nozzle. That is, rather than attempting to average the volume differences across the nozzles, these differences are understood and used explicitly in the print control process to combine different droplets (eg, from different nozzles or using different drive waveforms). And very accurate ink filling is obtained.

In one optional embodiment, the nozzles used for each target area in various passes, such that the printheads and / or substrates are " stepped " in varying amounts to eject the desired volume of droplets as appropriate. The nozzles can be changed. For example, droplets from one nozzle (eg, an average droplet volume of 9.95 pL) may be accumulated from the second nozzle (eg, 20.00 pL) by selectively offsetting the printhead or printhead assembly relative to the substrate. To obtain synthesis, average droplet volume of 10.05 pL). Multiple passes are planned so that each target area accommodates a specific cumulative charge that matches the desired target charge. That is, each target area (e.g., each well in a row of wells that will form a pixelated component of the display) will accommodate a planned combination of one or more droplet volumes, so that the printhead is relative to the substrate. Different geometric steps of can be used to obtain cumulative volumes within a specified tolerance range. In a more detailed feature of this embodiment, given the positional relationship of the nozzles to each other, a Pareto optimal solution is calculated and applied such that an allowable volume deviation in each target area is allowed within the specification but at the same time, The printhead / substrate movement can be planned to maximize the average simultaneous use of nozzles for each target deposition area. The statistical techniques discussed above can be used to ensure that the statistical model of synthetic (ie, multiple droplet) ink filling is within any confucius range. In selective purification, the function is applied to reduce and even minimize the number of printhead / substrate passes that printing is required to achieve this purpose. Reflecting these various features briefly, manufacturing costs are substantially reduced because printing of layers of material on a substrate can be performed quickly and efficiently.

In a typical application, the target areas containing ink are arranged in arrays, i.e., rows and columns, where the swath described in the relative printhead / substrate motion causes the ink to be drawn in every row (of the target area of the array). Will be deposited in a subset, but in a single pass, in a manner that covers all the columns of the array, and also includes, for example, rows, columns and / or printhead nozzles containing hundreds or thousands of rows, columns and / or printhead nozzles. The number of can be quite large.

Another optional embodiment solves the nozzle matching problem in a somewhat different manner. A plurality of sets of prearranged alternative nozzle spray waveforms with known (and different) droplet volume characteristics are made available to each nozzle: for example, a set of 4, 8, or another number of alternative waveforms It can be specified in hard-wired or other ways to provide a corresponding set of selectable, slightly different droplet volumes. Then, per-nozzle volume data (or difference data) and any associated statistical model are used to determine a set of nozzle-waveform combinations for each target region of the substrate, thereby providing a plurality of nozzles. A plan can be planned for the simultaneous deposition of the target area. In other words, the specific volumetric characteristics of each nozzle (in this case, each nozzle-waveform combination) and their associated distributions, confidence intervals, etc. can be used to obtain a specific fill volume with high reliability, ie nozzles Rather than attempt to correct sugar volume deviations, the deviations are specifically used in combination with obtaining a specific fill volume within a well understood statistical range. In general, to meet these purposes, there will be a large number of alternative combinations that can be used to deposit droplets in each desired range in each target region of the substrate. In more detailed embodiments, a “typical set” of nozzle waveforms can be shared across some (or even all) nozzles of the printhead, with droplet volumes per nozzle stored and mixing and matching different droplet volumes to determine Available to get fill. As an additional option, a calibration phase can be used to select different waveforms in an off-line process (eg, the dynamic incremental measurement process introduced above), where a calibration basis As a result, a set of specific nozzle injection waveforms can be selected to obtain each set of specifically desired volumetric characteristics. In other words, in further detailed embodiments, printing may be improved in a manner that improves print time, for example, by minimizing the number of scan or printhead passes, maximizing the use of simultaneous nozzles, or by optimizing some other criteria. Optimization can be performed to plan.

Yet another embodiment relates to using a plurality of printheads in a printhead assembly, wherein each printhead and nozzles of the printhead may be offset relative to one another (or correspondingly, each may be offset relative to one another). Printing structures having a plurality of rows of nozzles). With this intentional offset, the volume variation per nozzle between printheads (or rows of nozzles) can be intelligently combined by each pass or scan. In other words, there will generally be a large number of alternative combinations that can be used to deposit droplets to reach a desired range in each target area of the substrate, and in a detailed embodiment, optimization is performed such as scanning or printing. By minimizing the number of head passes, or by maximizing simultaneous nozzle use, other methods can be used to plan the use of offsets in a way that improves print time.

One advantage of the previously described technique is that it accepts droplet volume deviations but combines them to obtain a specific designated target area fill volume, thereby providing a high level of control over precise volume volumes as well as the ability to meet the desired filling confucation range This amount of variation can be obtained which is intentionally controlled (or ejected). The presence of geometric patterns from the deposition process, which can give a mura or observable pattern, can be mitigated through a plurality of techniques presented herein. That is, even slight differences in target fill volume at low spatial frequencies may be visible to the naked eye and thus create undesirable unintended geometric artifacts. Thus, in some embodiments, it is desirable to intentionally but arbitrarily vary within the specification the synthetic fill volume of a particular combination of droplets used to achieve synthetic fill in each target area or still within the specification. Using an exemplary tolerance of 49.75 pL-50.25 pL, for example, instead of simply randomly ensuring that all target area fillings are within a value within this tolerance range, any pattern of deviation or difference in the finished working display may be It may be desirable for such applications to intentionally introduce random deviations within this range so that they cannot be observed as a pattern. When applied to a color display, one exemplary embodiment provides such fill volume deviations in a statistically independent manner: (a) for the x dimension (eg, along the direction of the rows of the target area), and (b) for the y dimension. (E.g., along the direction of the columns of target regions), and / or (c) intentionally add over one or more color dimensions (e.g., independently for red to blue, blue to green, red to green target regions). . In one embodiment, the deviation is statistically independent for each of these dimensions. Such deviations are believed to render any fill volume deviations that are unobtrusive to the naked eye and thus contribute to the high image quality of such displays. For embodiments created through a repeatable set of "geometric steps" or offsets in the scan path using planned combinations of droplets from various nozzles, the use of subtle but intentional droplet volumes for each nozzle is ( That is, it provides a powerful technique for suppressing the possibility for Mura, without varying the scan path (generated through the use of multiple alternating injection waveforms for each nozzle). In one embodiment contemplated, for example, each nozzle is assigned to a set of alternating waveforms that produce their respective average volume within ± 10.0% of the ideal volume, with droplet combinations from the various nozzles Through the use of injected deviation (either through planned combinations of droplet volumes from various nozzle-waveform pairings, or through injected waveform deviations after selection / planning of nozzle-droplet combinations to achieve a particular fill) With Mura it can be planned according to the exact average (ie achieving accurate and intended filling). In other embodiments, intentionally different synthetic droplet volumes may be pre-positioned for each target area to produce cumulative filling, or different nozzle-droplet combinations may be applied along the scan path, or non-linear scan Paths can be used, all with the same effect. Other variations are also possible.

In addition, while conventional droplet measurement techniques can take a lot of time and days, they can cause errors in the printing process due to possible deviations in drop characteristics over long measurement cycles, while fast measurement techniques such as interference measurement techniques and related structures (introduced above) The use of the technique is more modern, more accurate, and enables a dynamic understanding of volume variation between nozzles and droplets, allowing the use of planned combinations as previously described with high reliability. For example, conventional droplet measurement techniques can be performed through the use of non-imaging techniques (eg, interferometry), which can take hours, while droplet measurement can continue to be up-to-date, resulting in process, voltage and temperature (PVT deviation), printhead nozzle degeneration, ink changes, and other dynamic processes that can affect the accuracy of the measurement. As previously mentioned, for example, through the use of a rolling measurement process that hides incremental droplet measurements at substrate loading and unloading times, droplet measurements can be retaken and updated almost continuously (eg, less than every 3-4 hours). For each nozzle), as previously described, one can present an accurate model that enables a synthetic filling scheme. In one embodiment, the droplets produced by all nozzles or nozzle-waveform pairing are remeasured (eg, from the beginning) periodically, such as every 2 to 24 hour periods, preferably at shorter time intervals, such as 2 hours. do. The rolling process is not required in all embodiments, ie in one embodiment, can be taken (or taken again) for all nozzles during the dedicated calibration process where printing is interrupted. To provide one example, in one possible embodiment, a printhead assembly having 6,000 nozzles and 24,000 nozzle-waveform combinations may be measured for 15 seconds during the substrate loading and unloading steps for a 90 second print cycle, respectively. And with each iteration, the problem of examining different rolling subsets of the 24,000 nozzle-waveform combinations continues until all nozzle-waveform combinations have been processed, and then returns to repeat the process in a circular fashion. Alternatively, in embodiments using a dedicated calibration process (eg every three hours), such a printhead assembly may be stopped for a period (eg, 30 minutes) so that all nozzles—before returning to activate printing. Express statistical model for waveform combination.

It is again noted that each of the optional techniques and the embodiments introduced above are contemplated as mutually alternative, on the contrary, such techniques may optionally be combined in any possible substitution or combination in the various embodiments. By way of example, measurement of droplet velocity and / or flight angle per nozzle / driving waveform is based on the determination that a particular nozzle-waveform combination produces a deviation “average” in which the droplets deviate, or where a particular nozzle-waveform combination exceeds a threshold. Based on the determination to generate a droplet statistical spread, it can be used to disqualify a "false" droplet for a given nozzle-waveform combination. In order to provide another non-limiting example, interferometric or other non-imaging techniques may be employed at nozzle-intermitted intervals such that the printhead assembly “stops” during loading and / or unloading of the substrate. By making these measurements incrementally and dynamically for the various windows of the waveform combination, they can be used to dynamically update the speed and / or flight angle. Obviously, many combinations and substitutions are possible based on the permutation introduced above.

An example will help introduce some concepts related to intelligent planning of fill volume per target area. Volume data per nozzle (or difference data) for a particular nozzle firing waveform is used to determine the set of possible nozzle-droplet volumes for each target region of the substrate, thereby allowing for simultaneous deposition of multiple target regions. Can plan for Generally there will be a large number of possible nozzle and / or combinations of drive waveforms that can be used to deposit ink droplets in multiple passes to fill each target area to the desired fill volume within a narrow tolerance range that meets specifications. . Referring briefly to the assumptions introduced using FIG. 1A, nozzles with the following non-limiting example, where the acceptable fill volume according to the specification is 49.75 pL to 50.25 pL (ie, within 0.5% of the target): Permissible filling volumes can also be obtained using different sets of / passes: (a) five passes of nozzle 2 (10.01 pL) for a total of 50.05 pL, (b) nozzle 1 (9.80) for a total of 49.92 pL one pass of pL) and four passes of nozzle 5 (10.03 pL), (c) one pass of nozzle 3 (9.89 pL) and four passes of nozzle 5 (10.03 pL) for a total of 50.01 pL, (d ) One pass of nozzle 3 (9.89 pL) for a total of 49.80 pL, three passes of nozzle 4 (9.96 pL) and one pass of nozzle 5 (10.03 pL), and (e) nozzle 2 for a total of 49.99 pL One pass of (10.01 pL), two passes of nozzle 4 (9.96 pL) and two passes of nozzle 5 (10.03 pL). Other combinations are also obvious. The droplet measurement technique introduced above can be used to obtain these expected droplet volumes, despite relatively larger statistical errors (eg, ± 2% of volume) associated with one droplet measurement. Thus, even if only one selection of nozzle drive waveforms is available for each nozzle (or all nozzles), the first embodiment introduced above can be used, each for depositing droplets (eg, in different target areas). It applies to as many nozzles as possible during the scan of, but it is possible to offset the printhead relative to the substrate with a series of planned offsets or "geometric steps" that combine the deposited droplets for each target area in a particular intended manner. That is, many combinations of nozzle-droplet volumes in this theory can be used to obtain a desired fill volume within a well understood range of statistical deviations that conform to specification tolerances, and certain embodiments may be used for scanning motion and / or nozzle drive waveforms. Selection effectively selects one of the acceptable drop combinations for each target region (ie, a specific set of each region), facilitating simultaneous filling of different rows and / or columns of the target region with respective nozzles. You can. By selecting the pattern of relative printhead / substrate motion in a manner to minimize the time that printing occurs, this first embodiment provides substantially enhanced manufacturing throughput. Optionally, this improvement can be used to scan or "pass" a printhead / substrate in such a way as to minimize the raw print time of the relative printhead / substrate movement or otherwise. It can be implemented in a form that minimizes the number of ". That is, the target area may be modified in a manner that meets specified criteria, such as a minimum printhead / substrate pass or scan, minimum printhead and / or substrate motion in the specified dimension (s), prints with minimal time, or other criteria. To fill, printhead / substrate movements (eg, scans) can be preplanned and used.

The same applies equally to all the assumptions of FIG. 1B in which the nozzles are not specifically aligned to their target areas. In other words, if the permissible fill volume is from 49.75 pL to 50.25 pL (ie within the range of 0.5% on either side of the target) according to the specification, several different sets of nozzles / passes, for example, non-limiting For all of the examples listed for FIG. 1A, and for further examples specific to the assumptions of FIG. 1B, acceptable fill volumes can also be obtained, where two adjacent nozzles may be used in one pass to fill a particular target area. Can be. For example, there are two passes of nozzle 4 (9.96 pL) and nozzle 5 (10.03 pL) for a total of 49.99 pL, and one pass of nozzle 2 (10.01 pL). Once again, each of these volumes can be equalized statistically based on many droplet measurements. For example, if the nozzles (4), (5), and (2) in this example relate to a statistical model that exhibits listed averages and 3σ values less than or equal to 0.5% of the listed averages, the cumulative filling is less than ± 0.5% of 49.99 pL. Will have a value of 3σ, which generally satisfies the specified tolerance with high statistical accuracy. For high-definition OLED displays (ie with millions of pixels), the 3σ (99.73%) value that closely matches the fill tolerance can be insufficient, for example, that potentially thousands of pixels are still outside the desired tolerance. Statistically represented, and for this reason, in many embodiments, larger spread measurements (eg, 6σ) match the composite fill tolerance, effectively ensuring that virtually all pixels of a high-definition display conform to manufacturing specifications.

These same principles apply to a plurality of nozzle per drive waveform embodiments. For example, in the assumptions presented in FIG. 1A, each nozzle can be driven by five different spray waveforms identified by spray waveforms A through E, with the final volume characteristics of the different nozzles for the different spray waveforms being In Table 1a. Given only the target area 104 and the nozzle 1, it would be possible to deposit a 50.00 pL target in five passes, for example a designated injection waveform D (for generating 9.96 pL droplets from the nozzle 1). By the first printhead pass using and the next four passes using the designated ejection waveform E (to generate 10.01 pL droplets from nozzle 1) (all without any offset in the scan path). Similarly, different combinations of injection waveforms may be used simultaneously in each pass for each nozzle, producing a volume close to the target value in each of the target regions without any offset in the scan path.

Table 1a

These same approaches apply equally to the hypothesis of FIG. 1B. For example, considering only the target area 154 and the nozzles 1 and 2 (ie, two nozzles overlapping the target area 154 during the scan), it is possible to obtain 50.00 pL in three passes, For example, the first printhead pass using nozzle (1) and designation waveform B (for droplet volume of 9.70 pL) and nozzle (2) and designation waveform C (for droplet volume of 10.10 pL), nozzle Second printhead pass using (1) and designation waveform E (for droplet volume of 10.01 pL) and nozzle (2) and designation waveform D (for droplet volume of 10.18 pL), and nozzle (1) and designation waveform It is possible to obtain with a third printhead pass using E (for droplet volume of 10.01 pL).

In a single row of target regions, for both the hypothesis of FIG. 1A and the hypothesis of FIG. Waveform E is used for nozzle 1, waveform A is used for nozzles 2, 4 and 5, and waveform C is used for nozzle 3 ( 10.01 pL + 10.01 pL + 9.99 pL + 9.96 pL + 10.03 pL = 50.00 pL), it would be possible to deposit exactly 50.00 pL from a single droplet from each nozzle for each target region in one row. It is also possible to deposit all the drops needed to achieve the target volume in one pass without even rotating the printhead. For example, the nozzle 1 can drop distribute using waveform D and distribute 4 drops from waveform E to region 104 in a single pass.

These same principles apply to the above mentioned printhead offset embodiment. For example, for the assumptions presented by FIG. 1A, the volume characteristics may reflect nozzles for the first printhead (eg, “printhead A”), each of which has a single spray waveform. And are integrated with four additional printheads (eg, printheads "B" through "E") having respective droplet volume characteristics per nozzle. When executing a scan pass, each of the nozzles identified as nozzles 1 to the printhead are aligned to print into the target area (eg, target area 104 of FIG. 1A) and identified as nozzles 2 from various printheads. The printheads are collectively configured such that each nozzle is aligned to print to a second target area (eg, target area 105 of FIG. 1A), where the volume characteristics of different nozzles for different printheads are It is described in Table 1b. Optionally, the respective printheads may be offset relative to each other, for example, using a motor that adjusts the spacing between scans. Considering only the target area 104 and the nozzle 1 on each printhead, it would be possible to deposit 50.00 pL in four passes, for example, both printhead D and printhead E would drop droplets into the target area. Only the first printhead pass to spray and printhead E will be possible with the next three passes to spray the droplet into the target area. Other combinations are possible using even fewer passes that can still produce in the target area a volume in the range of 49.75 pL to 50.25 pL, close to the 50.00 pL target in the target area. Again, considering only the target area 104 and the nozzle 1 on each printhead, for example, the first printhead passes through which droplets are ejected into the target area, and printheads D and E, for example. It would be possible to deposit 49.83 pL in two passes, both by a second printhead pass that sprays the droplet into the target area. Likewise, different combinations of nozzles from different printheads in each pass can be used simultaneously to create a volume close to the target value in each of the target areas without any offset in the scan path. Thus, using multiple passes in this manner would be advantageous in embodiments in which it is desirable to deposit droplets simultaneously on different target regions (eg, different rows of pixels). In other words, statistical accuracy can be ensured by planning the droplet measurement in a calculated manner to obtain the desired statistical characteristics related to the droplet volume per nozzle and / or per drive waveform and the average associated therewith.

Table 1B

All of the same schemes apply equally to the assumption of FIG. Again, considering only the target area 154 and the nozzles 1 and 2 on each printhead (i.e., nozzles overlapping with the target area 154 during scanning), for example, the printhead in two passes. 50.00 by the first printhead pass where C and E spray nozzles 1 and printheads B and C spray nozzle 2, and the second printhead pass where printhead C sprays nozzle 2, 50.00 It is possible to deposit pL. In a single pass, for example, 49.99 pL (high statistical accuracy) by a printhead pass where printheads C, D and E spray nozzles 1 and printhead B and printheads B and E spray nozzles 2 To be within the target range of 49.75 pL to 50.25 pL).

Optionally, in combination with the scan path offset, the use of alternate nozzle firing waveforms significantly increases the number of droplet volume combinations that can be obtained for a particular printhead, and as described above, these options It is further increased by the use of a plurality of printheads (or, equivalently, a plurality of rows of nozzles). For example, in the hypothetical example referred to by the description of FIG. 1 above, literally thousands of droplet volume combinations are possible, allowing combinations of five nozzles and eight alternating waveforms each with their own ejection characteristics (eg, droplet volume). Can provide different sets of. By optimizing the set of nozzle-waveform combinations for each target area (or each row of print wells in the array) and selecting a particular set of nozzle-waveform combinations, further optimization of printing according to the desired criteria is possible. In embodiments utilizing multiple printheads (or rows of printhead nozzles), the ability to selectively offset these printheads / rows further increases the number of combinations that can be applied per printhead / substrate scan. In other words, for these embodiments, assuming that multiple sets of (one or more) nozzle waveform combinations can be used alternately to obtain a specified fill volume, this embodiment is “acceptable” for each target area. A particular one of the sets is selected, wherein generally a particular one selection across the target areas corresponds to simultaneous printing of a plurality of target areas using a plurality of nozzles. That is, by varying parameters to minimize the time that printing occurs, each of these embodiments improves manufacturing throughput and the number of printhead / substrate scans or “passes” required, relative printhead / substrate along a particular dimension (s). It helps to meet the net distance of exercise, or other criteria.

Many other processes can be used and combined with the various techniques introduced above. For example, “tuning” the nozzle drive waveform (eg, shaping drive pulses, drive voltage, rising and falling slopes) on a nozzle basis to reduce variation in droplet volume per nozzle, for example. Changing the pulse width, the decay time, the number of pulses per drop, their level, and the like.

While certain applications referred to herein refer to the filling volume of individual fluid receptacles, or “wells”, the techniques mentioned above can be used to compare to other structures of the substrate (eg, transistors, pathways, diodes and It is also possible to use the aforementioned technique to deposit a "blanket coating" with a large area (relative to other electronic components). In this context, the fluid ink carrying the layer material (e.g., to be cured, dried or hardened in place to form a permanent device layer) will diffuse to a certain range, but (ink viscosity and Given other factors) will still retain certain properties relative to other target deposition regions of the substrate. In this context it is possible to deposit blanket layers, such as encapsulation layers or other layers, using, for example, specific and local control over the ink filling volume for each target area. . The techniques mentioned herein are not limited to the specifically presented applications or examples.

Other variations, advantages, and applications from the aforementioned techniques will be readily apparent to those skilled in the art. That is, these techniques can be applied to many different fields and are not limited to the manufacture of display devices or pixelated devices. As used herein, a printing “well” refers to any receptacle of a substrate that has a chemical or structural characteristic for accommodating the deposited ink, and thus restricts the flow of the ink. As will be exemplified below for OLED printing, this may include the situation in which each fluid receptacle receives a respective volume of ink and / or a respective type of ink, for example, the techniques mentioned above may be of different colors. In display applications used to deposit luminescent materials, successive printing processes may be performed for each color using respective printheads and respective inks, in which case each process is " every three times in the array. Every well of the third array (eg, sandwiching an array that overlaps the well for another color component), or every other "blue" color component). Each print well is an illustration of one type of target area possible. Other variations are also possible. In the present specification, "row" and "column" are used without meaning any absolute direction. For example, a "row" of print wells can extend the length or width of the substrate or in another way (linear or non-linear), generally speaking, "row" and "column" are each at least one independent. It will be used to refer to a direction representing the phosphorus dimension, but need not be true for all embodiments. In addition, since modern presses can use relative substrate / printhead motion including multiple dimensions, the relative motion need not be linear in path or speed, ie the relative motion of the printhead / substrate is straight or even continuous. There is no need to follow a path or speed. Thus, a "pass" or "scan" of a printhead relative to a substrate simply refers to an iteration involving relative printhead / substrate motion for depositing droplets onto a plurality of target areas using a plurality of nozzles. However, in many of the embodiments described below for an OLED printing process, each pass or scan can be substantially continuous linear motion, with each subsequent pass or scan offset by a geometric step relative to each other with the next pass or scan. Parallel. This offset or geometric step may have a difference in path or scan start position, average position, completion position or any other type of position offset and does not necessarily mean a parallel scan path. It should also be noted that the various embodiments mentioned herein refer to the use of “concurrent” of different nozzles for depositing on different target regions (eg, different rows of target regions), which term “simultaneous”. Does not require simultaneous droplet ejection, but rather may refer to the concept that different nozzles or groups of nozzles may be used to eject ink to their respective target areas mutually-exclusive during any scan or pass. It is only. For example, a first group of one or more nozzles may be sprayed during a particular scan to deposit first droplets in a first row of fluid wells, during which a first group of one or more nozzles are sprayed during this same particular scan. The second droplet can be deposited into a second row of fluid wells. The term "printhead" refers to a single or modular device with one or more nozzles used to print (squirt) ink onto a substrate. In contrast, a “printhead assembly” refers to an assembly or module element that supports one or more printheads as a group for common positioning relative to the substrate, so in some embodiments the printhead assembly may include only one printhead. In other embodiments, such an assembly may include six or more printheads. In some embodiments, the individual printheads can be offset relative to each other within such an assembly. In typical embodiments used for high volume manufacturing processes (eg, television flat panel displays), the printhead assembly is very large and includes many thousands of print nozzles, and depending on the embodiment, such assemblies are discussed herein. And may be designed to be connected around such an assembly to obtain per droplet measurement. For example, using a printhead assembly with six printheads and approximately 10,000 or more print nozzles, the printhead assembly can be serviced off- (print) axis within the press to support a variety of operations including droplet measurement. It may be "parked" in the station.

Using some principles of several different embodiments laid out, the present disclosure will be roughly organized as follows. 2A-2E will be used to introduce certain droplet measurement configurations for an imaging mass printhead assembly. Such a configuration may optionally be integrated into a flat panel display manufacturing device that prints an ink material to form a permanent thin film layer on a flat panel device substrate, for example. In an alternative embodiment, this configuration uses a three-dimensional representation of some or all of the optics associated with droplet measurement, such as for a printhead assembly having a plurality of printheads and thousands of ink jet nozzles that have been stationary within a printing station's service station. I can express it. 3A-4D will be used to introduce some general principles relating to nozzle matching problems, OLED printing / fabrication, and how embodiments solve the nozzle matching problems. These techniques can be used with the droplet measurement configuration mentioned. 5-7 will be used to illustrate a software process that can be used to plan droplet combinations for each target region of a substrate. 8A-B are used to illustrate the principles involved in forming a statistical model of droplet volume for each nozzle / waveform combination, and using these models to generate a statistical model of cumulative ink filling for each target area. do. These principles, in spite of nozzle consistency issues, ensure that, together with droplet measurement, the reliability of a synthetic ink fill that meets a specified tolerance range with quantifiable certainty (eg with 99% or better reliability per target area) Can be used to generate (ie, through the use of planned droplet combinations). 9A-10C are used to present some experimental data, ie experimental data that can demonstrate the effectiveness of the planned droplet combination techniques mentioned in improving target region filling consistency. 11-12 will be used to discuss exemplary applications for OLED panel fabrication and related printing and control means. 13A-13C are used to discuss printhead offsets that may be used to vary the drop combinations that may be deposited in each scan. 14A-15D are used to further discuss various, alternate nozzle spray waveforms that are applied to provide various droplet volumes or combinations. 16-17 will provide additional details on the structure and configuration of an industrial printing press including a droplet measurement device. 18A and 18B will each be used to discuss certain detailed embodiments of droplet measurement systems such as those integrated with such industrial printing presses. Finally, FIG. 19 will be used to discuss techniques for hiding droplet measurement time after other system processes, in order to maximize production time.

2A-2E are used to generally introduce a technique for droplet measurement per nozzle.

More specifically, FIG. 2A provides a depicted view showing the optical system 201 and the relatively large printhead assembly 203, wherein the printhead assembly has a plurality of individual nozzles, each having hundreds to thousands of nozzles. And a plurality of printheads 205A / 205B (eg 207). An ink supply (not shown) is fluidly connected to each nozzle (eg, nozzle 207), and a piezoelectric transducer (also not shown) is used to eject droplets of ink under the control of an electrical control signal per nozzle. . The nozzle design maintains a slight negative pressure of ink at each nozzle (eg, nozzle 207) to avoid flooding the nozzle plate, the electrical signal for a given nozzle activates the corresponding piezoelectric transducer, It is used to pressurize ink against a given nozzle to eject droplets from a given nozzle. In one embodiment, the control signal for each nozzle is normally zero volts, where a plus pulse or signal at a given voltage is used to eject droplets (once per pulse) for that nozzle for a particular nozzle, and another implementation. In an example, various, customized pulses (or more complex waveforms) may be used between the nozzles. However, in connection with the example provided by FIG. 2A, it is desirable to measure the volume of droplets generated by a particular nozzle (eg, nozzle 207), where the droplets are ejected downward from the print head (ie, three-dimensional). Assume that it is collected by a pittoon 209 in the " h " direction representing the z-axis height for the coordinate system 208. In typical applications, the dimension of "h" is typically about 1 millimeter or less and there are thousands of nozzles (eg, 10,000 nozzles) with their respective droplets measured in this manner individually in a working press. Thus, in order to accurately measure each droplet optically (i.e., droplets derived from a particular one of thousands of nozzles in a mass printhead assembly environment, into a roughly millimeter measurement window as just described), in the disclosed embodiments, Some techniques are used to accurately position elements of the optical assembly 201, printhead assembly 203, or both relative to each other for optical measurements.

In one embodiment, these techniques include (a) at least a portion of an optical system (e.g., dimensional plane 213) for precise positioning in the measurement area 215 immediately adjacent to any nozzle generating a droplet for optical calibration / measurement. A combination of xy motion control 211A in () and (b) planar optical return 211B (e.g., allowing for easy placement of the measurement area next to any nozzle, despite large printhead surface area) Use Thus, in an exemplary environment with more than about 10,000 print nozzles, such a motion system can position at least a portion of the optical system (eg, about 10,000), so that it is adjacent to the discharge path of each nozzle of the printhead assembly. It is located separately. As discussed below, two contemplated optical measurement techniques include shadow plots and interference measurements. Using each, the optics are typically adjusted in place, so that the correct focus is placed on the measurement area to capture the in-flingt droplets (e.g. to effectively image the shadows of the droplets in the case of shadowing). maintain. Typical droplets can be approximately microns in diameter, so the optical placement is typically very accurate and challenges exist with respect to the relative position of the printhead assembly and the measurement optics / measurement area. In some embodiments, to aid in this positioning, optics (mirrors, prisms, etc.) may be used to orient the light capture path to sense below the dimensional plane 213 emerging from the measurement area 215, thereby measuring the measurement optics. Can be located close to the measurement area without interference with the relative positioning of the optical system and printhead. Allows effective position control in a manner that is not limited by the deposition height h in millimeters at which the droplets are imaged or by the large x and y widths occupied by the printhead under review. Using an interferometry-based droplet measurement technique, separate rays of light incident at different angles to small droplets form an interference pattern that can be detected from a perspective that is generally orthogonal to the optical path, such that The optics capture light from an angle of approximately 90 degrees of the path of the source beam, and also in a manner that uses a bottom planar optical return for droplet parameter measurement. Other optical measurement techniques can also be used. In another variation of these embodiments, the motion system 211A is preferably an xyz-motion system optional, which allows selective connection and disconnection of the droplet measurement system without moving the printhead assembly during droplet measurement. Allow. In brief, considering an industrial manufacturing device with one or more large printhead assemblies, to maximize manufacturing uptime, each printhead assembly is sometimes "stopped" at a service station to perform one or more maintenance functions. Considering the pure size of the printhead and the number of nozzles, it may be desirable to perform a plurality of holding functions at once on various portions of the printhead. To that effect, in this embodiment, it may be more desirable to move the measurement / calibration device around the printhead than vice versa. This then allows for the connection of other non-optical holding processes associated with another nozzle if desired. To facilitate these actions, the printhead assembly may optionally be "stopped" for a system that identifies a particular nozzle or range of nozzles to be optically calibrated. When the printhead assembly or a given printhead is stopped, the motion system 211A is connected to move the at least a portion of the optical system relative to the "stopped" printhead assembly and to a location suitable for detecting droplets ejected from a particular nozzle. Positioning the measurement area 215 accurately, the use of the z-axis movement allows for the selective connection of the optical return optics from very far below the plane of the printhead and enables other maintenance operations instead of or in addition to optical calibration. . Unless stated otherwise, the use of the xyz-motion system allows for selective connection of a droplet measurement system independent of other test or test devices used in a service station environment. Such a structure is not required for all embodiments, e.g., with respect to FIGS. 16-17, for a measurement assembly with motion of both the measurement assembly and the printhead assembly, i.e., xy motion for droplet measurement. Means for allowing the z-axis motion of will be described. In addition, other alternatives are possible in which only the printhead assembly moves, the measurement assembly is stopped, or no rest of the printhead assembly is required.

Generally, the optics used for droplet measurement are a light source 217, an optional set of light transmitting optics 219 (directing light from the light source 217 to the measurement area 215, if desired), one The optical sensors 221 and the set of return optics 223 direct light used to measure the droplet (s) from the measurement region 215 to the one or more optical sensors 221. Optionally, the motion system 211A, along with the spitoon 209, allows one or more of these elements to allow the direction of the post-droplet measurement light from the measurement area 215 around the pitoon 209 to the down-plane position. In addition, it also provides a receptacle (eg, spitoon 209) to collect the ejected ink. In one embodiment, the light transfer optics 219 and / or the light return optics 223 use a mirror that directs light into and out of the measurement region 215 along a vertical dimension parallel to droplet movement. Moves the respective elements 217, 219, 221, 223 and spitoon 209 as integrated units during droplet measurement. This setting offers the advantage of not having to recalibrate the focus to the measurement area 215. As indicated at 211C, it is used to selectively supply source light from a position below the dimensional plane 213 of the light transmission optics measurement area, for example, as shown generally, the light source 217 and the measurement. Use optical sensor (s) 221 for directing light on both sides of spit 209 for the purpose. As indicated by reference numerals 225 and 227, the optical system may optionally include a lens for focus as well as a photodetector (e.g. for non-imaging techniques that do not rely on the processing of "photo" of many pixels. ). Selective use of z-motion control across the optical assembly and spytun allows for selective connection and disconnection of the optical system when the printhead assembly is "stopped" at any point and measured close to any nozzle Allow for accurate positioning of region 215. This stop of the xyz-motion of the printhead assembly and optical system 201 is not required for all embodiments. For example, in one embodiment, laser interferometry measures that the printhead assembly (and / or optical system) is in a deposition plane (eg, within or in parallel with plane 213) for imaging droplets from various nozzles. Or in parallel, it is used to measure droplet characteristics. Other combinations or substitutions are possible.

2B provides a flowchart related to droplet measurement for some embodiments. This flow chart is generally shown using reference numeral 231 in FIG. 2B. More specifically, as indicated by reference numeral 233, in this particular process, the printhead assembly is first stopped at a service station (not shown) of, for example, a printing press or deposition apparatus. The droplet measurement device is then connected 235 to the printhead assembly by selective connection of some or all of the optical system, eg, from below the deposition plane to a position where the optical system can measure individual droplets. ). At 237, such motion for one or more optical-system configurations for a stationary printhead may optionally be performed in the x, y and z dimensions.

As previously suggested, even single nozzle and associated nozzle spray drive waveforms (ie, signal level (s) used to eject the pulse (s) or droplets) may produce droplet volumes, trajectories, and velocities that vary slightly between the droplets. Can be generated. In accordance with the disclosure herein, in one embodiment, as indicated by reference number 239, the droplet measurement system obtains n measurements per droplet of the desired parameter, leading to statistical confidence regarding the expected measurement of that parameter. Serve In one embodiment, the measured parameter may be volume, while in other embodiments the measured parameter may be flight speed, flight trajectory or another parameter or a combination of a plurality of such parameters. In one embodiment, “n” may vary for each nozzle, while in another embodiment, “n” is a fixed number of measurements (eg, “24”) to be performed for each nozzle. And in still other embodiments, “n” refers to the minimum number of measurements such that additional measurements can be performed to dynamically adjust the measured statistical characteristics of the parameter or to rebuild the reliability. Clearly, many variations are possible. For the example provided by FIG. 2B, it is assumed that the droplet volume is measured to obtain an accurate mean and just confidence interval representing the expected droplet volume from a given nozzle. This allows for selective planning of droplet combinations (using multiple nozzles and / or drive waveforms), while maintaining a reliable distribution of synthetic ink is filled in the target area for the expected target (ie, droplets). For the synthesis of means). As indicated by the optional process boxes 241 and 243, the interferometry or shadow plot is considered an optical measurement process that ideally enables instantaneous or near instantaneous measurement and calculation of the volume (or other desired parameter). do. Such quick-measurements can be updated frequently and dynamically, for example, to account for changes in ink properties over time (including viscosity and constituents), temperature, power supply variations and other factors. . Based on this, the shadow painting typically captures an image of the droplet, for example using a high resolution CCD camera as the light sensor means, while the droplet captures a single image at multiple locations (eg using a flashing light source). Images can be accurately imaged in the capture frame, and the image processing software typically calculates the droplet volume in relation to a finite amount of time so that imaging of sufficient droplet population from a large printhead assembly (eg with thousands of nozzles) It may take several hours. Interference measurements that rely on the detection of a plurality of binary photo detectors and interference pattern spacing based on the output of such detectors are non-imaging techniques (ie, do not require image analysis), which are faster than shadow painting or other techniques (eg To generate droplet volumetric measurements, for example, using a 10,000 nozzle printhead assembly, it is expected that mass measurement populations for each of thousands of nozzles can be obtained within minutes, and that droplet measurements can be performed frequently and dynamically. do. As noted previously, in one alternative embodiment, droplet measurement (or measurement of other parameters such as trajectory and / or velocity) may be performed periodically, in an intermittent process, wherein the droplet measurement system is in accordance with a schedule. Engaged or connected between substrates (eg, substrate loaded or unloaded), or stacked for other assembly and / or other printhead holding processes. For embodiments in which alternating nozzle drive waveforms are to be used in a specific manner for each nozzle, a fast measurement system (eg, an interference measurement system) is a statistical group for each nozzle and for each alternating drive waveform for that nozzle. Allowing expression quickly allows for the planned droplet combination of droplets produced by various nozzle-waveform pairings, as previously suggested. For deflection numbers 245 and 247, by measuring the expected droplet volume more accurately than 0.01 pL (and / or between nozzle-waveform pairings) between nozzles, very accurate droplet combinations can be planned for the target deposition area, where The synthetic filling may be planned with 0.01 pL resolution, and the target volume may be maintained within or better than specified errors (eg, tolerances) in the range of 0.5% of the target volume, as indicated by reference number 247. As such, in one embodiment, the measurement population for each nozzle or each nozzle-waveform pairing is reliable for each such nozzle or nozzle-waveform pairing, i.e. 3σ reliability (4σ, less than the specification maximum filling error). Other statistical measures such as 5σ, 6σ, etc.) are planned to generate a distribution model. Once sufficient measurements are taken for the various droplets, the filling associated with the combination of these droplets can be evaluated and used to plan print 248 in the most efficient and possible manner. As indicated by the separate lines 249, droplet measurement can be performed with intermittent switching back and forth between the active printing process and the measurement and calibration process.

2C shows one possible process flow 251 associated with the planning of droplet measurements per nozzle (or per nozzle-waveform pairing) and / or the initiation of statistical data for modeling the behavior of each nozzle. As indicated by reference numeral 253, in this process, data specifying the desired tolerance range is first received, which can be established, for example, according to manufacturer specifications. In one embodiment, for example, such a tolerance or tolerance may be specified as ± 5.0% of a given target, and in another embodiment, ± 2.5%, ± 2.0%, ± 1.0%, ± 0.6 of the desired target droplet size. Ranges of% or ± 0.5% may be used. It is also possible to specify a range or a set of allowable values in an alternating manner. Regardless of the method described herein depending on the desired tolerance and droplet system measurement error, the threshold number of measurements is identified (255). As indicated above, this number can be chosen to achieve a plurality of objectives, i.e. (a) droplet measurement to provide a reliable measurement of the expected droplet parameters (eg, average volume, velocity or trajectory). Obtaining a sufficiently large population of (b) obtaining a sufficiently large population of droplet measurements to model the deviation in the droplet parameters (eg, standard deviation or σ for a given parameter), and / or (c) printing process In the meantime, in order to disqualify the use of a particular nozzle / nozzle-waveform pairing, it is to obtain data large enough to identify a nozzle or nozzle-waveform pairing that is larger than the expected error. Using any planned number of droplet measurements or the desired metrics, or if the relevant minimums are defined, the measurements are performed using the droplet measurement system 259 (eg, using optical techniques as discussed herein). (257). Then, the measurement for each nozzle (or nose-wave) is performed for process decision block 261 until the specified criteria are met. If the number of measurements meets the planned criteria, the method ends at process block 269. If further measurements need to be made, the measurement process is looped until sufficient measurements are obtained, as referenced in FIG. 2C.

2C illustrates a number of exemplary process variants. First, as indicated by reference numeral 263, this measurement process is selectively applied to all nozzles (and / or all possible nozzle / waveform combinations) of the printhead assembly. This is not the case for all embodiments. For example, in one embodiment (see discussion of FIGS. 14A-15C below), rather than thoroughly testing each of the possible waveforms, a potentially unlimited number of drive waveform variants may be applied to the parameters of the droplets ejected for a given nozzle. The droplet measurement process is a set of determined waveforms representing a wide distribution of possible waveforms, and an interpolation search process used to select a repetitive, small number of waveforms (e.g., ± 10 of the desired droplet size). May generate average droplet volume over a range of%). In another embodiment, based on initial measurements, if a given nozzle is considered defective (eg, if the droplet volume is greater than 20% distribution from the desired mean), that nozzle (or nozzle-waveform pairing) is no longer considered. You can't. In another example, if a print scan is actually planned to not use any nozzles, it is recommended that only the nozzles that are enabled and used in the planned scanning to perform dynamic and additional droplet measurements until at least some type of error or dispersion criterion is reached. desirable. In other words, there are many possibilities. The functional block 263 simply indicates that the applied process need not be applied to all nozzles (or nozzle-waveform pairings). Second, reference numeral 265 indicates that, in one embodiment, the minimum criterion is associated with a minimum threshold that differentiates each nozzle or nozzle-waveform pairing. To cite some examples relating to this function, in one embodiment, droplet measurements are performed for a given nozzle or nozzle-waveform pairing, and distribution spread measurements (e.g., dispersion, standard deviation, or another measurement) are calculated. This is calculated as a measure beyond the raw threshold until the spread measure meets the determined criteria. As can be seen, if the minimum is 10 droplet measurements per nozzle, for example, 10 droplet measurements for a particular nozzle produce a variance larger than the expected variance, and further measurements are made until the desired spread is achieved (mean 3σ ≦ 1.0% of volume), or some maximum number of measurements will be performed uniquely for a given nozzle until performed. Such an embodiment for example can result in a varying number of measurements per nozzle, for example with measurement iterations designed to achieve certain minimum criteria (eg, the smallest number of measurements and spread measurements below the threshold in this example). Third, as indicated by reference number 267, for example, to obtain an “exactly 24” droplet measurement, for example a nozzle (or per nozzle-waveform), or to obtain x measurements per hour, dead- reckon). Finally, irrespective of measurement management techniques, measurements can be applied to any nozzle or nozzle-waveform combination to qualification (pass) or disqualification. Requoting a possible implementation option, after the performance of the threshold number of measurements, any nozzle or nozzle-waveform may be qualified or disqualified based on measurement data at 270. For example, if the ideal droplet volume is 10.00 pL in one application, nozzle / nozzle-waveform pairings that do not produce an average droplet volume of 9.90 pL-10.10 pL are immediately disqualified, and the same approach, for example, minimizes measurement. Any nozzle / nozzle-waveform pairing that is taken for a statistical spread along the number and produces a droplet spread greater than 0.5% (eg, dispersion, standard deviation, etc.) is immediately disqualified. Once again, many implementations exist.

FIG. 2D is a schematic diagram of one embodiment of a droplet measurement system predicted on optical techniques, generally referred to as FIG. 271. More specifically, a printhead 273 with five listed print nozzles is shown in cross section, arranged in a row of nozzles that eject fluid ink in the z-direction (indicated by legend 274). . A light source 275A is arranged on the side of the printhead to illuminate the measurement area 278 through which the droplets will pass for measurement, and in the case of FIG. 2D, this measurement area (and some or all of the optical system) is the printhead. It is arranged to measure the droplets coming from the nozzle (3). The light source 275A is shown outside of one side of the printhead 273, towards the light to the light measurement area (i.e., in millimeter-grade height, denoted by variable h), so as not to interfere with the printhead 273 Light path 277 illuminating any plurality of nozzles. As indicated by reference number 275B, in one embodiment, the light source is mounted at the bottom deposition plane 289 (and top periphery of the spiton 286) to secure the optics to the droplet path from any nozzle. The distance positioning can be made relatively easy, that is, five nozzles are shown in FIG. 2D, and in one embodiment there are hundreds to thousands or more of nozzles. Below deposition planar light generation using the optics used to direct illumination to the droplet measurement area 278 can be used to facilitate positioning of the optical system and droplet measurement system with respect to any nozzle of the printhead 273 shown. Enable selective connection and disconnection (eg, for an optional service station, as previously described). In the example shown, mirror 285A is used to redirect light from light source 275B to enter the droplet within measurement area 278 that travels from printhead 273 to spite 286. By way of non-limiting example, other means of positioning the optical path to the light source 275B, such as, for example, prisms, fiber optic cables, etc. may also be used. For embodiments in which imaging measurement techniques are used (eg, shadow plots), the light sources 275A / 275B may be flashing thermal light sources or monochromatic sources. FIG. 2D shows the light from a third origin location directed along path 275C, where the light source is outside of the drawing page, the optical path routing optics (eg, along the y dimension shown by reference legend 274). With or without assistance, light is directed into or out of the drawing page, which positioning framework is an example of the interference measurement depending on the direction of the interference pattern resulting from the direction orthogonal (or at another angle) to the illumination path. Can be used for. Regardless of the relative arrangement of the illumination source, the light is directed along the illumination plane 290 between the light path 227, the position of the printhead 273 and the deposition plane 290, and the measured light (ie, measured It should be noted that (from the droplet) is routed by the optical path routing optics 285B from the imaging plane to a photo detector mounted to the underlying deposition plane 289. In other words, this allows for a limited direction and focus of light, despite the large printhead size and the relatively small height h. Also, techniques such as light path routing optics 285A, mirrors, prisms, optical fibers or other light redirecting devices may be used to validate down-deposition-plane routing of light return. As can be seen in FIG. 2D, the measurement light is directed to a focusing optic 279 (eg, a lens), which is directed to the photo detector 280. The distance of the optical path between the focusing optics and the measurement area is identified by the distance f, which represents the focal length of the optical system. As previously suggested, droplet measurement (depending on the optical technique) provides the exact focus needed to properly image the droplet, and in this sense, the optical path routing optics 285B for the system represented by FIG. 2D. ), Focal optics 279, droplet measurement area 278 and spytoon 286 lenses are all moved in an integrated unit, from different nozzles to common chassis 283, as represented by the connections shown. Measure the droplets. Light sources 275A / 275B and light source directing optics may also optionally be coupled to these cases, depending on the embodiment.

In an interferometry-based system conceptually represented by FIG. 2D, the light source 275A / 275B (or light path 275C) is an interference pattern, with the beam split into two or more different configurations at some point along the optical path. Note that it may be a laser used to produce the Additional features regarding these optics and the use of a plurality of beams to generate the interference pattern will be discussed further below in connection with FIG. 18B, and for the time being the laser source (including the light source for interferometry) It should be assumed to be covered by 275A / 275B / 275C.

2E shows another schematic diagram of an embodiment of a droplet measurement system that is predicted for the optical technique generally referred to by reference number 291. More specifically, the embodiment seen in FIG. 2E requires interference measurements to measure droplet parameters (such as volume). As before, this configuration requires a printhead 273, a measurement area 278, a chassis 283, and a spiton 286. However, in this embodiment, the laser is specifically used as the light source 292 to produce light rays directed through the illumination path 293 to the measurement area. Note that typically two or more beams are directed in this manner, as further described below. An interference pattern is generated in the droplets in the measurement region 278, and this interference pattern is generated in the droplets in the measurement region 278, and this interference pattern is substantially in the illumination path 293, as represented by reference numeral 297. It is observed from an orthogonal direction. Although this same relationship (measured from a direction not parallel to the light path) is represented by FIG. 2D (eg, using path 275C), in FIG. 2E, the divergence measurement angle is measured essentially in the downward direction. Is directed down the plane of region 278. The photo detector 295 is non-imaging in that the use of a camera is not required (although multiple orphan detectors are typically used), and the use of image processing to identify droplet contours in the pixelated image is not required. In practice, the interference measurement approach is to simply measure the change in the interference pattern as a droplet path through the region of coincident rays, using droplet volumes derived from the results obtained. . The use of two or more rays (or an increased number of detectors) allows the measurement of droplet trajectory and velocity and other parameters. As before, the light source 292, spiton 286 and light detector 295 are moved into one (ie, with a common chassis 283), allowing for the preservation of accurate optical path parameters. In one embodiment, the motion of the optical system is again performed in three dimensions with respect to the " stopped " printhead assembly such that the printhead assembly can be selectively disconnected from the droplet measurement device while in the service station, thereby mass printing. Droplet measuring devices for measuring any thousands of nozzles of the head can be easily and accurately positioned.

As noted previously, with a suitable configuration of a droplet measurement device or system, an industrial printer (eg, used for fabricating an OLED device) can have nozzles and their resulting droplets that are calibrated repeatedly, so that any target It can allow to plan a very accurate droplet combination within the area. That is, the measurement device can be used to quickly express an accurate, tightly grouped statistical distribution of volume for each nozzle and for each waveform used for the nozzle, which is a combination of droplets used to achieve synthetic filling. Enable accurate planning. In other embodiments, this same technique is used to form a model for droplet velocity and flight angle so that the model for these parameters can be applied to the printing process.

Any of these various techniques (and any printing or synthetic filling techniques introduced in this disclosure) may appear in various products and / or at various stages of manufacture. For example, FIG. 3A shows a plurality of various implementation steps, collectively indicated by reference numeral 301, each of which represents a possible discrete implementation of the technique introduced above. First, the technique introduced above can be implemented as instructions (software for controlling a computer or printer) stored on a non-transitory machine-readable medium, as indicated by figure 303. Second, for computer icon 305, these techniques may be implemented as part of a computer or network in a company that designs or manufactures components for sale or use in other products. For example, the techniques introduced above may be implemented as design software by a company that conducts a design for a high-definition television (HDTV) manufacturer or browses, and alternatively, these techniques may be used to produce a television (or display screen). Can be used directly by such manufacturers. Third, as previously introduced and illustrated using the storage medium picture 307, the previously introduced technique may take the form of a press command, for example, if the press is activated, as discussed previously, Stored instructions or data will enable the construction of one or more layers that rely on the use of planned droplet accumulation techniques. Fourth, as represented by manufacturing device icon 309, the techniques introduced above may be implemented as part of a manufacturing apparatus or machine, or in the form of a printing press in such apparatus or machine. For example, a manufacturing machine may have a droplet measurement and conversion of externally supplied “layer data” such that the printer can obviously optimize / increase the printing process using the techniques described herein by the machine. Can be sold or customized in such a way that it is automatically converted to a printer command (eg, through the use of software). In addition, such data can be calculated off-line, so that it can be reapplied on a reproducible basis in a scalable, pipelined manufacturing process that manufactures many configurations. Note that the specific description of the manufacturing device icon 309 represents one example press device to be discussed below (eg, with reference to FIGS. 11-12). The technique introduced above may be implemented in an assembly, such as an array 311 of a plurality of configurations to be sold separately. In FIG. 3, for example, these various configurations are shown in the form of an array of semi-finished flat panel devices. Later it will be separated and sold for integration into end customer products. For example, the device shown may have one or more layers (eg, color composition layer, semiconductor layer, encapsulation layer or other material) deposited depending on the method introduced above. The techniques introduced above may be, for example, in the form of a display screen for a portable digital device 313 (eg, an electronic pad or a smartphone), a television display screen 315 (eg, an HDTV), or other type of device. In the form of, it may be embodied in the form of end-fold products. For example, FIG. 3A uses a solar cell diagram 317, whereby the process introduced above may be a different type of electronic device, such as a target region structure (one or more layers of individual cells constituting the cumulative device) or blanket layer ( For example, an encapsulation layer for a TV or solar cell). Obviously, other examples are possible.

The techniques introduced above can be applied to any of the steps or configurations shown in FIG. 3A, without limitation. For example, one embodiment of the techniques disclosed herein is an end customer device, and the second embodiment of the techniques disclosed herein is the fabrication of layers using a combination of specific nozzle volumes to obtain a fill per specific target area. A device comprising data for controlling the nozzle volume can be predetermined or can be measured and applied in place. Yet another embodiment is a deposition machine that uses a printer, for example, to print one or more inks using the techniques introduced above. These techniques can be executed on one machine or more than one machine, for example, a network or a series of machines where various steps are applied to various machines. All such embodiments and others may use the techniques introduced by the present disclosure independently or collectively.

As shown in FIG. 3B, in one application, a printing process may be used to deposit one or more layers of material onto a substrate. The aforementioned technique can be used to generate a press control command (eg, an electronic control file that can be sent to a press) for later use in device manufacturing. In one particular application, these instructions can be designed for an inkjet printing process useful for printing layers of low cost scalable organic light emitting diode ("OLED") displays. More specifically, the aforementioned techniques can be applied to the pixelated color components of one or more light emitting or other layers of such OLED devices, such as red, " green " and " blue " This example application is non-limiting, regardless of whether these layers are luminescent and whether the device is a display device. It can be applied to the manufacture of tangible layers and / or devices In this exemplary application, various conventional design limitations of the inkjet printhead can be applied to the process efficiency of the various layers of the OLED stack that can be printed using various inkjet printing systems. Provides Challenges for Film Coating Uniformity These challenges can be addressed through the description herein.

More specifically, FIG. 3B is a top view of one embodiment of the printer 321. The printer includes a printhead assembly 323 used to deposit the flowable ink onto the substrate 325. Unlike a printer that prints text and graphics, this example printer 321 is used in the manufacturing process for depositing a flowable ink having a desired thickness. That is, in general manufacturing applications, the ink carries the material to be used to form the permanent layer of the finished device, where the layer has a specifically desired thickness. The thickness of the layer produced by the deposition of fluid ink depends on the volume of ink applied. Generally, the ink is characterized by one or more materials that will form part of the finished layer formed as a monomer, polymer, or material carried by a solvent or other transport medium. In one embodiment, these materials are organic. After deposition of the ink, the ink may be dried, cured, or hardened to form a permanent layer, for example, some applications employ an ultraviolet (UV) curing process. The liquid monomer is converted to a solid polymer, and other processes dry the ink to remove the solvent and leave the transported material in a permanent location. Another process is also possible. There are many other variations that distinguish the depicted printing process from conventional graphic and text applications, for example, in some embodiments, to control the unwanted atmosphere or to control the surrounding atmosphere where the deposition of the desired layer of material will be something other than air. Is performed in a controlled environment to rule out this. For example, as will be described further below, one contemplated application is printing in the presence of a controlled atmosphere, such as an inert atmosphere, non-limiting examples such as nitrogen, noble gases, and any combination thereof. Manufacturing means are used to place the printer 321 into the gas chamber to be performed.

As further shown in FIG. 3B, printhead assembly 323 includes a plurality of nozzles, such as nozzle 327. In FIG. 3B, for convenience of illustration, the printhead assembly 323 and nozzles are shown as openings at the top of the page, but these nozzles face down toward the substrate and are hidden from the perspective of FIG. 3B (ie, 3B actually shows a cross sectional view of the printhead assembly 323). Although the nozzles are shown as being arranged in rows and columns (eg, exemplary rows 328 and columns 329), this is not required in all embodiments, i.e., some implementations merely provide a single row of nozzles (e.g., , Only row 328). In addition, it is possible for a row of nozzles to be disposed on their respective printheads, where, as mentioned above, each printhead is (optionally) offset separately from one another. In applications where a printing press is used to produce a material for a portion of a display device, such as for each of the respective red, green, and blue color components of the display device, the printing press is generally for each different ink or material. A dedicated printhead assembly will be used, and the techniques mentioned herein can be applied individually to each corresponding printhead or printhead assembly.

3B shows one printhead assembly 323 (ie, not shown separately, one or more individual printheads). The printer 321 includes two different motion means which in this example can be used to position the printhead assembly 323 relative to the substrate 325. First, a traveler or carriage 331 may be used to mount the printhead assembly 323 and to enable the relative motion indicated by arrow 333. This motion mechanism may optionally drive printhead assembly 323 to a service station (if present), which is indicated by numeral 334 in FIG. 3B. However, substrate transport means can then be used to move the substrate along one or more dimensions relative to the traveler. For example, as indicated by arrow 335, the substrate transporter may enable movement in each of the two orthogonal directions, such as along the x and y Cartesian dimension 337, and selecting It can support substrate rotation as a matter. In one embodiment, the substrate transport means includes a gas floatation table that is used to selectively fix and allow movement of the substrate on a gas bearing. Optionally, the printer enables rotation of the printhead assembly 323 relative to the traveler 331, as shown by the rotating graphic 338. By such rotation, the apparent spacing and relative configuration of the nozzle 327 can be changed relative to the substrate, for example, so that each target region of the substrate is a specific region, or has a spacing relative to another target region. If determined, the rotation of the printhead assembly and / or substrate may change the relative spacing of the nozzles in a direction along or perpendicular to the scan direction. In one embodiment, the height of the printhead assembly 323 relative to the substrate 325 may also be changed along the z-catetian dimension, for example, orthogonal to the drawing plane of FIG. 3B.

Two scan paths are shown by directional arrows 339 and 340, respectively, in FIG. 3B. In short, the substrate motion means moves the substrate back and forth in the direction of the arrows 339 and 340 as the printhead moves by a geometric step or offset in the direction of the arrow 333. Using these kinematic combinations, the nozzles of the printhead assembly can reach any desired area of the substrate to deposit ink. As mentioned above, the ink is deposited in a controlled manner with discrete target regions of the substrate. These target regions can be arranged, for example, in rows and columns along the y and x dimensions, respectively. Each scan along the direction of the row of target areas sweeps the row of nozzles so that they intersect with each of the columns of the target area of the substrate (eg along direction 339) , Row 328, appears perpendicular to the rows and columns of the target area. This need not be the case in all embodiments. For the efficiency of the movement, the next scan or pass reverses the direction of this movement and addresses the columns of the target area in the reversed order, ie along the direction 340.

The arrangement of the target area in this example is shown by the highlighted area 341 shown enlarged on the right side of the figure. That is, two rows of pixels each having red, green, and blue color components are represented by number 343, and each column of pixels orthogonal to the scan direction 339/340 is represented by number 345. In the upper leftmost pixel, red, green and blue color components appear to occupy separate target regions 347, 349 and 351 as part of each overlapping array of regions. Each color component in each pixel may also have associated electronics represented, for example, by the number 353. If the device to be manufactured is a backlit display (eg as part of a conventional type of LCD television), these electronics can control the selective masking of light filtered by the red, green and blue regions. If the device to be manufactured is a newer type of display, i.e., the red, green and blue regions produce their own light with directly corresponding color characteristics, these electronics 353 will produce the desired light generation and optical characteristics. Patterned electrodes and other layers of material that contribute to the.

3C is an enlarged cross-sectional view of the printhead 373 and substrate 375 taken from the perspective view of line C-C. More specifically, reference numeral 371 generally indicates a printing press and reference numeral 378 denotes a row of print nozzles 377. Each nozzle is designated by the number (1), (2), (3), and the like. Typical printheads have a plurality of such nozzles, such as 64, 128 or another number, and in one embodiment, there may be more than 1,000-10,000 nozzles arranged in one or more rows. As mentioned above, the printhead in this embodiment moves in the direction indicated by arrow 383 relative to the substrate to cause a geometric step or offset between scans. Depending on the substrate movement means, the substrate may move orthogonal to this direction (eg, orthogonal to the illustrated page plane of FIG. 3C) and in some embodiments the direction indicated by arrow 385. FIG. 3C shows a row 383 of each target region 379 of the substrate, which in this case is arranged in a “well” to receive the deposited ink and retain the deposited ink within the confinement structure of each well. For the purposes of FIG. 3C, it will be assumed that only one ink appears (eg, each illustrated well 379 represents only one color, such as a red color component, of the display and the other remaining color components and wells associated therewith. Is not shown). The figures are not drawn to scale, for example nozzles are numbered from (1) to (16), while the wells are shown to represent 702 wells, represented by (A) to (ZZ). In some embodiments, using a scan of relative printhead / substrate movement in the direction orthogonal to the page in the perspective of FIG. 3C, the illustrated printhead with 16 nozzles is ink in 16 wells simultaneously in the direction of arrow 381. The nozzles will be aligned in their wells to deposit them. In another embodiment, as mentioned above (eg, with reference to FIG. 1B), the nozzle density will be much greater than the target area density, and by any scan or pass, a subset of nozzles (eg, any nozzle) Depending on whether it traverses each target region, one or a group of nozzles) will be used for deposition into each target region. For example, again using an illustrative example of 16 nozzles, nozzles 1-3 can be used to deposit ink in a first target area, while at the same time mutually exclusive for a particular path, The nozzles 7-10 may be used simultaneously to deposit ink in the second target area.

Conventionally, the press can be operated to reciprocate with subsequent scans as needed, for example, until five droplets are deposited in each well, and simultaneously operate to deposit ink in 16 well rows using the 16 nozzles shown. And the printhead is advanced by a fixed step, which is an integer multiple of the width of the swath traversed by the scan as needed. However, the technique provided by the present invention takes advantage of the inherent variation in droplet volume produced by different nozzles in a combination calculated to produce a specific fill volume for each well. Different embodiments use different techniques for obtaining these combinations. In one embodiment, the geometric steps are varied to obtain different combinations, and any number other than an integer multiple of the width described by the printhead movement width can be any number. For example, suitably for depositing a selected set of droplet combinations in each well 379 in FIG. 3C, the geometric step is, in fact, in this example, printing at a tenth interval of one row of wells. It may be one sixteenth of the movement width of the printhead, indicating the relative displacement between the head and the substrate. The next offset or geometric step may be different, such as to be suitable for the particular combination of droplets desired for each well, for example a hypothetical offset of 5/16 of the printhead movement width corresponding to the integer spacing of the wells, This deviation may continue in both positive and negative steps as needed to deposit the ink to obtain the desired fill volume. Different types or sizes of offsets are possible and the step size does not have to be fixed per scan or a specific fraction of the well spacing. In many manufacturing applications, however, it is desirable to minimize printing time in order to maximize production speed and minimize manufacturing costs per unit, and for this purpose, in certain embodiments, the total number of scans, the total number of geometric steps, offset or Printhead movements are planned and arranged to minimize the size of the geometric steps and the cumulative distance traversed by the geometric steps. These or other means can be used individually, or together, or in any desired combination to minimize the total print time. In embodiments where independently offsetable nozzle rows are used (eg, a plurality of printheads), geometric steps may be expressed in part as offsets between printheads or nozzle rows, which offsets the total offset of the printhead component ( For example, a fixed step to a printhead assembly) can be used to cause variable size geometric steps and thus deposit droplet combinations in each well. In embodiments where only deviations in nozzle drive waveforms are used, conventional fixed steps can be used, where droplet volume variations are caused using multiple printheads and / or multiple printhead passes. As will be discussed below, in one embodiment, nozzle drive waveforms can be programmed for each nozzle between droplets, such that each nozzle can create and contribute a respective droplet volume per well in a well row. have.

4A-4D are used to provide further details regarding the dependence on the specific droplet volume to obtain the desired fill volume.

4A shows an illustration 401 of the printhead 404 and two related diagrams shown below the printhead 401. The printhead is used in one embodiment, which optionally provides a non-static geometric step of the printhead to the substrate, with a particular printhead nozzle (e.g. 16 nozzles in total and nozzles 1-5 in the figure). The numeral 405 is used to indicate an offset that aligns to different target regions (in this example, five target regions 413, 414, 415, 416, and 417). Returning to the example of FIG. 1A, the nozzles (1)-(16) have droplet volumes 9.80, 10.01, 9.89, 9.96, 10.03, 9.99, 10.08, 10.00, 10.09, 10.07, 9.99, 9.92, 9.97, 9.81, 10.04 and When generating 9.95 pL of flowable ink (eg, average droplet volume), respectively, and if it is desirable to deposit 50.00 pL per target area of ± 0.5 percent of this value, the printhead is used in five passes or scans. The droplets are deposited using geometric steps 0, -1, -1, -2 and -4, and the total charge values 49.82, 49.92, 49.95, 49.90 and 50.16 per region (expected average) as shown in the figure. It is apparent that pL can be derived, which is within the desired tolerance range of 49.75-50.25pL for each of the illustrated target regions. In this example all steps are represented incrementally relative to the previous position, but other measures are possible. Depending on the deviation in the volume per droplet expected, it is hypothesized that by many droplet measurements (e.g., measuring more than 20-30 droplets per nozzle), as described above, the filling will conform to the desired tolerance range. It is also possible to ensure that the expected deviation of each droplet volume can be made very small, allowing high reliability in the phase of the expected synthetic volume. Thus, as shown, a combination of droplets can be used in an intended manner that depends on the respective droplet volume and the desired fill amount for each target region, so that a high level of reliability, precise, controlled fill can be obtained. have.

This figure may be used to indicate nozzle drive waveform deviations and / or the use of a plurality of printheads. For example, if nozzle reference numbers (1)-(16) refer to the droplet volume for a single nozzle generated by 16 different drive waveforms (i.e., using waveforms 1-16), the theoretical target area ( By using several different drive waveforms, such as waveform numbers 1, 2, 3, 5, and 9 for 413, the fill volume per area can be obtained. Indeed, because process variations can lead to different per nozzle characteristics, the system will measure the droplet volume for each nozzle for each waveform and intelligently plan the droplet combination based on this. Nozzles (1)-(15) refer to a plurality of printheads (e.g., reference numerals (1)-(5) refer to a first printhead, and reference numerals (6)-(10) refer to a second printhead). In an embodiment that refers to a printhead, and reference numerals (11)-(15) refer to a third printhead), an offset between printheads can be used to reduce the number of passes or scans, for example, The rightmost target area 417 can cause three droplets to be deposited in one pass, such as droplets having droplet volumes of 10.03, 10.09 and 9.97 pL (printhead 1, 0 offset; printhead 2 ), +1 offset; printhead (3), +2 offset). It will be apparent that a combination of these various techniques will facilitate many possible combinations of specific volume droplets to achieve specific fill volumes within the tolerance range. In FIG. 4A, it can be seen that the deviation of the cumulative ink filling volume between the target regions is small and within tolerance, that is, within 49.82 pL to 50.16 pL.

4B shows an exemplary illustration 421 of a series of printhead scans, where each scan is perpendicular to arrow 422 and the nozzles are in different rectangles or bars, such as reference numerals 423-430. Is expressed. In relation to this figure, it should be assumed that the assumed relative movement of the printhead / substrate is advanced in a sequence of variable size geometric steps. In general, each step will specify a scan that sweeps multiple columns of the target area (e.g. pixels) up to a single column of five areas (represented by reference numerals 413-417) appearing on the plane of the drawing page. . For example, a scan comprising a first scan 423 that appears to be positioned on the right side relative to the substrate such that only the nozzles 1 and 2 are aligned with the target areas 416 and 417, respectively, at the top Appear in lower order. Within each print scan illustration (e.g., box 423), a circle represents each nozzle, and a filled black circle indicates that the nozzle will be ejected when the nozzle is above the specifically depicted target area during the scan, A "hollow", ie, circle filled with white indicates that the nozzle will not be ejected when related (but may be sprayed for other target areas encountered during the scan). In this embodiment, each nozzle is sprayed in a binary manner, that is, each nozzle is not sprayed or sprayed according to any adjustable parameters, for example, for each target area encountered during the scan. Droplet volumes can be deposited. For any of the embodiments described herein (ie, in embodiments in which a plurality of injection waveforms in which waveform parameters are adjusted between droplets are used) this "binary" injection scheme may optionally be used. . In the first pass 423, nozzle 1 is sprayed to deposit 9.80 pL droplets from the rightmost to the second target region, and nozzle 2 is sprayed to deposit 10.01 pL droplets to the rightmost target region 417. can do. The scan continues to sweep the remaining columns of the target area (eg, another row of pixel wells), depositing ink droplets as appropriate. After the first pass 423 is completed, the printhead is advanced by -3 geometric steps, which moves the printhead to the left relative to the substrate, so that the nozzle 1 is now in a second scan, opposite the first scan. It will cross the target area 413 during 424. During this second scan 424, nozzles 2, 3, 4, and 5 will also traverse regions 414, 415, 416, and 417, respectively. When the circle filled with black is appropriate, the nozzles 1, 2, 3, and 5 are sprayed, and the intrinsic characteristics of the nozzles 1, 2, 3, and 5, respectively, Corresponding drop volumes 9.80pL, 10.01pL, 9.89pL and 10.03pL will be deposited. In any one pass, the nozzles in the nozzle row used to deposit the ink will do this mutually exclusively to their respective target areas, for example, in the case of the pass 424, the nozzle 1 is the target area 413. Is used to deposit ink (but does not deposit ink in any of the target areas 414-417), and the nozzle 2 is used to deposit ink (but not the area 413 or 415-) in the target area 414. No ink is deposited in any of 417, and the nozzle 3 does not deposit ink in any of the areas 413-414 or 416-417 to deposit ink in the target area 364. Nozzle 5 is used to deposit ink in the target area 417 (but not deposit ink in any of the areas 413-416). A third scan 425 advances the printhead by one row (-1 geometric steps) of the target area such that nozzles 2, 3, 4, 5 and 6 are the area during the scan. (413, 414, 415, and 417) will be traversed, respectively, and the black filled nozzle graphic will show that during this pass, each nozzle (2)-(6) has the expected droplet volume 10.01, 9.89, 9.96, 10.03, respectively. And 9.99 pL.

If the printing process is interrupted at this point, region 417 will have a charge of 30.03 pL (10.01 pL + 10.03 pL + 9.99 pL), corresponding to three droplets, for example, while region 413 is 2 It will have a charge of 19.81 pL (9.80 pL + 10.01 pL) corresponding to 2 drops. In one embodiment, the scan pattern follows the back and forth pattern represented by arrows 339 and 340 of FIG. 3B. Subsequent passes 426-430 (or scans of a plurality of rows of these plurality of regions) across these target regions each perform the following depositions: (a) With a continuous scan, the nozzle 2 in the region 413 Deposition of 10.01 pL, 0.00 pL, 0.00 pL, 10.08 pL and 10.09 pL droplets corresponding to the pass by (3), (4), (7) and (9); (b) In the continuous scan, 0.00pL, 0.00pL, 10.03pL, corresponding to the respective paths by the nozzles (3), (4), (5), (8), and (10) in the region 414, Deposition of 10.00 pL and 10.07 pL droplets; (c) 9.89pL, 9.96pL, 10.03pL, 9.99pL corresponding to the paths by the nozzles (4), (5), (6), (9) and (11) in the region 415 by continuous scanning. , Deposition of 10.09 pL and 0.00 pL droplets; (d) 0.00pL, 9.99pL, 10.08pL, 10.07pL corresponding to the paths by nozzles (5), (6), (7), (10), and (12) in the region 416 by continuous scanning And deposition of 0.00pL droplets; And (e) 9.99 pL, 0.00 pL, 10.00 pL, 0.00 corresponding to the paths by nozzles 6, 7, 8, 11, and 13 in the region 417 in a continuous scan. deposition of pL and 0.00pL droplets. In other words, the nozzle of this example has only a single spray waveform (ie, these droplet volumetric characteristics do not change with the scan) and is used on a binary basis, for example, in the fifth scan 427, the nozzle 7 is not sprayed. Thus no droplet is generated for region 417 (0.00 pL), and in subsequent scans it is ejected to produce 10.08 pL droplets for region 416.

As shown in the graph at the bottom of the page, this hypothetical scanning process is 49.99pL, 50.00pL, 49.96, which is within the preferred range (49.75pL-50.25pL) of the target value (50.00pL) of plus or minus ½ percent. It produces the expected cumulative charge of pL, 49.99 pL and 50.02 pL. In this example, a nozzle was used to deposit ink into a plurality of target areas generally at the same time for each scan, with each illustrated area (ie, a graphically identified area of reference numerals 413-417). For this particular combination of droplet volumes is planned such that a plurality of droplets can be deposited in each target region by multiple passes. Specific sets (or specific combinations) of droplet volumes (e.g., for regions 413), where eight illustrated passes produce a fill volume within a specified tolerance range (e.g., nozzles 1, 2, 2) , Or combinations of droplets of (7) and (9), but other sets of possible droplets may also be used. For example, alternatively, it may have also been possible to use five droplets (5x10.01 pL = 50.05 pL) from nozzle 2 for region 413, but (for example) nozzle 3 (9.89). Since pL) cannot be used extensively at the same time, additional scans are needed (i.e., 5 droplets from this nozzle would be 5x9.89 = 49.45 pL outside the desired tolerance range), which could have been inefficient. In this example, continuing from FIG. 4B, to use less printing time, use fewer passes, smaller geometric steps and possibly smaller cumulative geometric step distances, or some other criteria according to some other criteria. The sequence of was selected. The illustrated example is for illustrative purposes only, and it may be possible to reduce the number of scans to less than eight times to obtain a target fill amount using the presented droplet volume. In some embodiments, the scanning process is planned in such a way as to avoid a worst-case scenario where multiple scans (eg, one scan per row of target area by a printhead rotated 90 degrees) are required. In another embodiment, this optimization is applied to a degree based on one or more maximum or minimum values, such as, for example, a scan being given the smallest number of possible times when all possible droplet combinations are given for each target area for a particular ink. Plan your scan in such a way that you derive it.

4C shows a diagram similar to FIG. 4B, which corresponds to the use of various nozzle-drive waveforms for each nozzle. As will be appreciated, in an ink jet printhead, ink is typically ejected using a piezo actuator, which expands and contracts the fluid reservoir to eject ink from each print nozzle. The ink is kept under some negative pressure to avoid flooding at the nozzle plate in the reservoir, and a voltage pulse is applied to the actuator to eject the droplets with properties that depend on the size and shape of the voltage pulse. Therefore, various pulse features can result in various volumes, velocities and other features of the ejected droplets. In FIG. 4C, various pre-planned voltage pulse waveforms were determined to produce a series of various droplet volumes (and associated droplet volume probability distributions). Scanning is generally indicated by reference number 441, where each scan 443-447 generates a direction perpendicular to the bars 443-447, and within the scan bar (e.g., box 443), the numeric display is a particular print. The head nozzles represent the head nozzles, and the text displays the various waveforms for the particular nozzle. For example, reference numeral "1-A" denotes the first drive waveform "A" used for the actuator for the nozzle 1, while reference numeral "1-C" denotes the actuator for the nozzle (1). Denotes a third drive waveform " C " During the calibration procedure, any number of waveforms can be tested to select a waveform that produces the expected droplet volume (or set of multiple droplets) that matches the ideal target droplet volume. In FIG. 4C, for example, testing a plurality of waveforms for nozzle 1 can produce the results of two specific waveforms (eg, “A” and “C” are expected droplet volumes, such as close to the desired 10.00 pL, such as , 9.94pL and 10.01pL average, respectively). In other words, if the expected mean cannot be generated through testing that exactly matches the ideal droplet volume (eg, 10.00 pL), two or more waveforms are selected, such as nozzles (1), (3), (4) and As shown for (5), the desired ideal volumes can be bracketed, such as 9.94 pL / 10.01 pL, 9.99 pL / 10.01 pL, 10.03 pL / 9.95 pL, and 9.95 / 10.04 pL. As in the above example, various droplets can be combined using various drive waveforms to specifically plan the cumulative filling for each target region within the desired tolerances. For the example of FIG. 4C, it is not necessary to offset the printhead assembly between scans to achieve these combinations, but in many embodiments, the use of multiple nozzle waveforms is fractional-swath Combined with a -width) offset, it is possible to develop many possible droplet combinations that can be used to generate a target fill using a minimum number of scans (and therefore a minimum substrate per print). In FIG. 4C, it can be seen that the depicted processes produce a virtual fill that is an expected fill volume of very tightly grouped, eg, 49.99 pL-50.02 pL.

4D shows an exemplary illustration 471 of printhead 474 and two related diagrams appearing below printhead 474, with the exception of having nozzles that are not specifically assigned to particular wells. similar. Optionally, the printhead is used in one embodiment to provide a non-fixed geometric step of the printhead relative to the substrate, and reference numeral 472 is used to designate a particular printhead nozzle (e.g. A total of 16 nozzles, including 1)-(5), may indicate an offset that aligns with a different target area (two areas 474 and 475 in this example). Again according to the assumption of FIG. 4A, the nozzles predict the droplet volumes of 9.80, 10.01, 9.89, 9.96, 10.03, 9.99, 10.08, 10.00, 10.09, 10.07, 9.99, 9.92, 9.97, 9.81, 10.04 and 9.95 pL, respectively. If it is desired to generate a volume of droplets, and deposit 50.00 pL per target area of ± 0.5 percent of this value, the printhead uses geometric steps 0, -1, and -3, respectively, and adds one or more droplets per scan, respectively. By spraying onto a target area of, it can be used to deposit droplets in three passes or scans. This will lead to total charge values per region, 49.93 and 50.10, as shown in the figures, which are apparently within the preferred tolerance range of 49.75-50.25 pL for each of the depicted target regions. Thus, as shown, the same approach applies equally to nozzles that are not aligned in the wells, and combining droplets in an intentional manner depends on the respective droplet volume and the desired fill amount for each target area. Precise and controlled filling can be achieved. In addition, as described above with respect to the assumptions of FIG. 3A, this same figure may be used to indicate nozzle drive waveform variation and / or use of a plurality of printheads. For example, if nozzle reference numbers (1)-(16) refer to droplet volumes for a single nozzle generated by 16 different drive waveforms (ie, using waveforms 1-16), in theory By using different drive waveforms, the filling volume per area can be obtained simply. Those skilled in the art will appreciate that for nozzles where the same approach as described above with reference to FIGS. 4B-4C is also not specifically aligned to the well, that is, a group of one or more nozzles may be used for simultaneous droplet deposition into each well. It can be seen that the same applies when used. Finally, FIGS. 4A-D also show a relatively simple example, where in general applications there may be hundreds to thousands of nozzles and millions of target areas. For example, the fabrication of each pixel color component of the current high definition television screen (eg, pixels with red, green, and blue wells, respectively, with pixels arranged at a vertical resolution of 1080 horizontal lines and a horizontal resolution of 1920 vertical lines). In the application to which the technique disclosed in the above is applied, there are approximately 6 million wells (i.e., three overlapping arrays with 2 million wells each) capable of containing ink. Next generation televisions are expected to increase this resolution by more than four times. In such a process, to improve printing speed, the printhead may utilize thousands of printing nozzles, for example, there may be an enormous number of possible printing process permutations. The simplified examples presented above can be used to introduce the concepts, but given the enormous numbers presented in the usual combinations, the permutations presented by real television applications are quite complex, and print optimization is generally complicated by software. It should be understood that this is applied using mathematical operations. 5-7 are used to provide a non-limiting example of how these operations can be applied.

An exemplary process for planning printing is introduced by FIG. 5. This process and associated methods and devices are generally referred to by number 501.

More specifically, the droplet volume is specifically determined 503 for each nozzle (and for each nozzle for each waveform when multiple drive waveforms are applied). Such measurements can, for example, measure droplets during various techniques, including, but not limited to, flight (e.g., during proof printing or during real-time printing operations) and determine droplet shape, velocity, trajectory and / or other This can be done using optical-imaging or laser-imaging or non-limiting devices (or factory-resident machines) that are built into the press that accurately calculates volume based on factors. In certain embodiments, as mentioned, each measurement is approximately accurate, although the droplet volume from a single nozzle generated using a single drive waveform may vary from droplet to droplet. To this end, droplet measurement techniques can be used to develop statistical models for liquid crystals from each nozzle, and for each nozzle-waveform combination, with each specific droplet volume expected from a given nozzle and a given nozzle drive waveform. Expressed as the average droplet volume. Other measurement techniques, such as printing ink, and then calculating individual droplet volumes based on pattern recognition using post-printing imaging or other techniques, may also be used. Alternatively, the identification may be based on data supplied by a printing press or printhead manufacturer, such as measurements taken in a factory well and provided to the machine (or online) prior to the manufacturing process. In some applications, droplet volume characteristics may change over time depending on ink viscosity or type, temperature, nozzle clogging or other deterioration, or by other inducements, and thus one embodiment. In, for example, when there is a power up (or when another type of power cycle event appears), with each new print of the substrate, when the specified time expires, other schedules Depending on or without schedule, droplet volume measurement can be performed dynamically in situ. In one embodiment, such measurements are performed on moving windows of print nozzles and nozzle-waveform combinations to obtain dynamic updates whenever a new flat panel substrate is loaded or unloaded, as mentioned previously. Is intermittently performed. As indicated by reference numeral 504, this data (measured or provided) is stored for use in the optimization process.

In addition to the droplet volume data per nozzle (and optionally per drive waveform), information 505 related to the desired fill volume for each target area is also received. This data may be a single target fill value to be applied to all target regions, each target fill value to be applied to an individual target region, a row of target regions or a column of target regions, or any other partitioned values. For example, when applied to fabricate a single layer of "blanket" material that is large relative to individual electronic device structures (e.g., transistors or pathways), such data may (e. G. It can consist of a single thickness applied to the entire layer as a basis, which translates into the desired ink fill volume per target area, in which case the data can correspond to each target area or consist of a plurality of target areas. To a common value for each " printed cell " As another example, the data may represent a specific value (50.00 pL) for one or more wells, where range data may be provided or understood on the basis of context. As will be appreciated from these examples, the preferred filling can be specified in various other forms, including but not limited to thickness data or volume data. Optionally, additional filtering or process criteria may also be provided or performed by the receiving device, for example, as mentioned above, the random deviation of the filling volume by the receiving device may be changed to one or more provided thickness or volume parameters. It can be injected to render line effects invisible to the naked eye in the finished display. This deviation can be performed previously (and provided as a charge per target area that varies per area) or obtained independently and transparently from the receiving device, for example by a downstream computer or printer.

Based on the target fill volume for each region and for individual droplet volume measurements (ie per printhead nozzle and nozzle drive waveform), optionally a combination of various droplets to be summed to the fill volume within the desired tolerance range. Proceed to calculate (ie, process block 506). As mentioned above, this range may be provided with the target filling data or may be "understood" depending on the context. In one embodiment, the range of ± 1 percent of the provided charge value is understood. In another embodiment, a range of ± 1/2 the percent of a provided fill value is understood. It is apparent that there are many other possibilities for tolerance ranges, whether larger or smaller than these exemplary ranges.

Here, an example of one possible method for calculating a set of possible droplet combinations will be provided. Returning to the simplified example described above, there are five nozzles, each nozzle having its respective assumed average droplet volumes of 9.80pL, 10.01pL, 9.89pL, 9.96pL, and 10.03pL, and ± ½ in five wells. It is assumed that it is desirable to deposit a target volume of 50.00 pL in percent (49.75 pL-50.25 pL). This method starts by determining the number of droplets that can be combined to reach but not exceed the tolerance range, and by determining the minimum and maximum number of droplets for each nozzle from the nozzles that can be used with any acceptable permutation. do. For example, in this assumption, given the minimum and maximum droplet volumes of the nozzle, one droplet from nozzle 1, two droplets from nozzle 3 and four droplets from nozzle 4 are random. It can be expected that it can be used in combination. This step limits the number of combinations that need to be considered. With constraints on established considerations, the method takes into account the combination of the required number of droplets (five in this example), taking each nozzle in turn. For example, the method first starts for nozzle 1 with the understanding that the only acceptable combination associated with nozzle 1 is characterized by less than one drop from this nozzle, at a given calculated average. . In view of the combinations associated with a single droplet from this nozzle, the method takes into account the minimum and maximum droplet volumes of each of the other nozzle-waveform combinations to be considered, for example, the nozzle 1 has a 9.80 pL for a particular drive waveform. Assuming it is determined to produce an average droplet volume, one droplet from nozzle 3 or two droplets from nozzle 4 may be used in combination with droplets from nozzle 1 to reach a desired tolerance range. . The method comprises a combination of droplets from nozzle 1 and a combination of four droplets from other nozzles, such as four droplets from nozzle 2 or 5, three droplets from nozzle 2. , And one droplet or the like from the nozzle 4 are considered. Given a combination involving only the nozzle 1 to simplify the description, any of the following different combinations associated with the first nozzle may be used within tolerances:

{1 (1), 4 (2)}, {1 (1), 3 (2), 1 (4)}, {1 (1), 3 (2), 1 (5)}, {1 (1 ), 2 (2), 1 (4), 1 (5)}, {1 (1), 1 (2), 1 (3), 2 (5)}, {1 (1), 1 (2) , 1 (4), 2 (5)}, {1 (1), 1 (2), 3 (5)}, {1 (1), 1 (3), 3 (5)}, {1 (1 ), 2 (4), 2 (5)}, {1 (1), 1 (4), 3 (5)} and {1 (1), 4 (5)}

In the mathematical expressions provided above, the use of braces represents a set of five droplets representing a combination of droplet volumes from one or more nozzles, with each parenthesis within these braces identifying a particular nozzle, for example, the expression {1 (1 ), 4 (2)} represents one droplet from nozzle 1 and four droplets from nozzle 2, 9.80 pL + (4x10.01 pL) = 49.84 pL, which is a synthetic fill within the specified tolerance range It is expected to generate. Indeed, the method in this example considers the maximum number of droplets from the nozzle 1 that can be used to produce the desired tolerance, evaluates the combination associated with this maximum number, reduces the number by one, and varies the average Repeat the consideration process based on. In one embodiment, this process is repeated to determine all possible sets of non-redundant droplet combinations that can be used. When the combination associated with the nozzle 1 has been fully explored, the method proceeds to the combination associated with the nozzle 2 without involving the nozzle 1 and repeats the process to determine whether a desired tolerance range can be obtained. To test the combined mean of each possible nozzle combination. In this embodiment, for example, the method determines that a combination of two or more droplets from nozzle 1 cannot be used, so that one droplet from nozzle 1 and four droplets from other nozzles and We begin to consider related combinations in various combinations. In practice the method evaluates whether four droplets of nozzle 2 can be used and determines that it can be {1 (1), 4 (2)}, reducing this number by one (from nozzle 2 Three droplets), determining that this number can be used in combination with a single droplet from nozzle 4 or (5), allowing the set {1 (1), 3 (2), 1 (4)}, { 1 (1), 3 (2), 1 (5)} can be calculated. The method then further reduces the number of allowed droplets from the nozzle 2 by one, evaluates the combination of {1 (1), 2 (2) ....} and then {1 (1 ), 1 (2) ....} and the like. If the combination associated with the nozzle 2 is considered a combination with droplets from the nozzle 1, the method takes the next nozzle, ie the nozzle 3 and is associated with this nozzle but not with the nozzle 2. Considering the combination of the nozzles 1, it is determined that only combinations allowed by {1 (1), 1 (3), 3 (5)} are given. If all combinations related to droplets from nozzle 1 have been considered, the method relates to droplets from nozzle 2 but not to droplets 5. {5 (2)}, {4 (2), 1 (3)}, {4 (2), 1 (4)}, {4 (2), 1 (5)}, {3 (2), 2 (3)}, {3 (2), 1 (3), 1 (4)} and the like.

The same approach applies equally when the nozzle can be driven by a plurality of injection waveforms, each producing a different droplet volume. These additional nozzle-waveform combinations simply provide additional droplet volume averages for use in selecting a set of droplet combinations that are within the target volume tolerance range. By enabling a greater number of acceptable droplet combinations to increase the likelihood of simultaneously ejecting droplets from a large portion of the nozzle in each pass, the use of multiple jet waveforms may also improve the efficiency of the printing process. Can be. If the nozzle has a plurality of drive waveforms and geometric steps are also used, the selection of the set of droplet combinations will include both the geometric offset to be used in the particular scan and the nozzle waveform to be used for each nozzle.

For the purpose of illustration, a brute force approach has been described, and in practice a huge number of possible combinations of large numbers of nozzles and target areas (e.g., more than 128 for each) will be presented. will be. However, this calculation works well within the capabilities of high speed processors with appropriate software. There are also various mathematical shortcuts that can be applied to reduce the calculations. For example, in certain embodiments, the method may exclude any combination that would correspond to the use of less than half of the nozzles available in any one pass under consideration (or alternatively, in any single pass). Limiting consideration of combinations that minimize volume variations between the target regions TR). In one embodiment, the method determines only a specific set of droplet combinations that will produce an acceptable composite filling value, and in a second embodiment, the method selects all possible sets of droplet combinations that will produce an acceptable synthetic filling value. Calculate exhaustively. In multiple iterations, a print scan is performed, taking an iterative approach in which the volume of ink still remaining to be deposited to reach the desired tolerance range (s) is considered for the purpose of optimizing subsequent scans. It is also possible to use. Other processes are also possible.

As an initial operation, if the same fill value (and tolerance) is applied to each target area, the combinations are calculated once (eg for one target area) and these possible droplet combinations are stored for initial use in each target area. It is enough to do. This is not the case for all established calculation methods and for all applications (eg, in some embodiments, the range of charges allowed for every target area may vary).

In another embodiment, the method may use mathematical shortening, such as approximation, matrix math, random selection or other techniques, to determine the set of drop combinations allowed for each target area.

As indicated by process block 507, once the set of allowed combinations for each target region is determined, the method performs scanning in a manner that correlates with a particular set (or droplet combination) for each target region. Plan effectively. This specific set selection is such that a particular set (one set for each target region) represents process savings through the use of at least one scan to deposit droplet volumes onto multiple target regions simultaneously. Is performed. That is, in an ideal case, the method selects one particular set for each target area, and the particular set represents a particular droplet volume combination in such a way that the printhead can print to multiple rows of the target area at once. . The particular drop selection of the selected combination represents a printing process that meets specified criteria, such as a minimum printing time, a minimum number of scans, a minimum size of geometric steps, a minimum cumulative geometric step distance, or other criteria. These criteria are represented by reference numeral 508 of FIG. In one embodiment, the optimization is Pareto optimal and a particular set is selected in such a way as to minimize each of the plurality of scans and then minimize the cumulative geometric step distance and the size of the geometric step. In other words, this selection of a particular set may be performed in any desired manner, some non-limiting examples being mentioned below.

In one example, the method selects a droplet from each set for each target region corresponding to a particular geometric step or waveform applied to all the regions under consideration, and then subtracts the droplet from the available set and the rest. Determine. For example, the initially available set of choices for each of the five target regions is {1 (1), 4 (2)}, {1 (1), 3 (2), 1 (4), {1 ( 1), 3 (2), 1 (5)}, {1 (1), 2 (2), 1 (4), 1 (5)}, {1 (1), 1 (2), 1 (3 ), 2 (5)}, {1 (1), 1 (2), 1 (4), 2 (5)}, {1 (1), 1 (2), 3 (5)}, {1 ( 1), 1 (3), 3 (5)}, {1 (1), 2 (4), 2 (5)}, {1 (1), 1 (4), 3 (5)} and {1 (1), 4 (5)}, this embodiment subtracts one droplet (1) with this initial set to obtain the remainder specific to the first of the five target regions, and one from the initial set. The droplet 2 is subtracted to obtain a specific remainder in the second target region of the five target regions, and one droplet 3 is removed from the initial set to obtain a remainder specific to the third target region. This evaluation will represent the geometric step "0". The method will then evaluate the remainder and repeat the process for other geometric steps. For example, if a geometric step of " -1 " is applied, the method will subtract one droplet 2 from the initial set for the first of the five target regions, and the initial set from the second target region. We will subtract one droplet (3) from and repeat it and evaluate the rest.

When selecting a particular geometric step (and nozzle spray) as part of the printing plan, the method analyzes the various remainders according to the score or priority function and selects the geometric step with the best score. In one embodiment, the score is applied to further weight the steps of (a) maximizing the number of nozzles used simultaneously, and (b) maximizing the minimum number of combinations remaining for the affected target area. For example, a scan using droplets from four nozzles during a scan will be given more preference weights than a scan using droplets from only two nozzles. Similarly, taking into account the different steps, using the aforementioned subtraction process yields one, two, two, four and five remaining combinations for each target area for one possible step and the second possible. If 2, 2, 2, 3 and 4 remaining combinations are derived for each target area for the step, the method will give higher weight to the latter (ie the largest minimum number is "2"). will be. In practice, suitable weight coefficients can be empirically formed. It is apparent that other algorithms may be applied and other forms of analysis or algorithm shortening may be applied. For example, matrix mathematics can be used (eg, using eigenvector analysis) to determine the specific droplet combination and associated scanning parameters that meet the specified criteria. In another variation, other formulas may be used that mitigate line effects using planned random fill variations.

Once a particular set and / or scan path is selected (507), the printer operations are sequenced (509). For example, sets of droplets can generally be deposited in any order when only cumulative filling volumes are considered. If printing is planned to minimize the number of scans or passes, the order of geometric steps may be selected to minimize printhead / substrate movement, for example, scans {0, + 3, -2 allowed in hypothetical examples. If, + 6 and -4} include geometric steps, these scans may be reordered to minimize printhead / substrate movement and thus improve print speed, e.g., scans may be sequenced in steps {0, + 1, + 1, + 2 and +4}. Compared to the first sequence of geometric steps with cumulative step increment distance 15 {0, + 3, -2, + 6 and -4}, the second sequence of geometric steps with cumulative step increment distance 7 {0, + 1 , +2, +0 and +4} promote faster press response.

As indicated by reference numeral 510, in an application with a large number of target area rows to accommodate the same target fill amount, a particular solution may also be represented in a repeating pattern that will be reproduced across a subset of the substrate. Can be. For example, if there are 128 nozzles arranged in a single row and 1024 rows of the target area in one application, it is expected that an optimal scan pattern can be determined for a subset area of 255 or less target area rows. Thus, the same print pattern can be applied to four or more subset regions of the substrate in this example. Thus, some embodiments utilize a repeatable pattern as represented by optional process block 510.

The non-transitory machine readable medium icon 511, optionally, means that the method described above is implemented with instructions for controlling one or more machines (eg, software or firmware for controlling one or more processors). Non-transitory media can be any machine-readable physical medium, such as flash drive, floppy disk, tape, server storage or mass storage, dynamic random access memory (DRAM), compact disk (CD), or other local or remote. It may include a storage device. This storage device can be implemented as part of a larger machine (eg, a resident memory in a desktop computer or printer) or in isolation (eg a flash drive or standalone storage device that will later transfer files to another computer or printer). Each of the functions mentioned with reference to FIG. 5 may be implemented on a single medium representation (eg, a single floppy disk) or on a plurality of individual storage devices as part of a combined program or as a standalone module.

As indicated by reference numeral 513 in FIG. 5, when the planning process is complete, a set of printer commands that includes nozzle ejection data for the printhead and instructions for relative movement between the printhead and the substrate to support the ejection pattern. Will be generated to effectively represent. This data, effectively representing the scan path, scan order, and other data, can be stored for later use (eg, as shown by the non-transitory machine readable media icon 515) or control the printer 517. Electronic file 513 that is immediately applied to deposit ink representing the selected combination (especially a particular set of nozzles per target area). For example, the method can be applied to a standalone computer, where instruction data is stored in RAM for later use or download to another machine. Alternatively, the method can be implemented by a printer and dynamically applied to "inbound" data, so that the scanning can be automatically planned according to printing parameters (eg, nozzle-droplet-volume data). Many other alternatives are possible.

6A-6D provide diagrams generally associated with nozzle selection and scan planning processes. The scan need not be continuous or linear in the direction or speed of motion and need not proceed in all directions from one side of the substrate to the other.

The first block diagram is shown by reference numeral 601 in FIG. 6A, which shows many of the example processes mentioned in the previous description. The method first begins by retrieving a set of acceptable droplet volume combinations for each target region from memory (603). These sets can be calculated dynamically or in advance, for example, using software on different machines. Database icon 605 represents a locally-stored database (eg, a database stored in local RAM) or a remote database. The method then effectively selects a particular one of the allowed sets for each target area 607. In many embodiments this selection is indirect, i.e., the method processes combinations that are allowed to select a particular scan (e.g., using the techniques mentioned above), and in practice these scans define a particular set. Nevertheless, by planning the scan, the method selects a particular set of combinations for each target area. This data can then be used to order the scans and complete the movement and firing pattern as mentioned above (609).

The center and right side of FIG. 6A plan the scan path and nozzle ejection pattern, and in practice, show several process options for selecting a particular droplet combination for each target area in a manner that indicates print optimization. As indicated at 608, the illustrated technique represents one possible way to perform this task. In reference numeral 611, the analysis may include determining the minimum and maximum use of each nozzle (or nozzle-waveform combination if the nozzle is driven by two or more spray waveforms) in an acceptable combination. If a particular nozzle is bad (e.g. not spraying or spraying with an unacceptable trajectory), the nozzle may be excluded from use (and under consideration) of options. Then, if the nozzle has a very small or very large expected droplet volume, this may limit the number of droplets that can be used from the nozzle in acceptable combinations; Reference numeral 611 denotes preprocessing which reduces the number of combinations to be considered. As indicated by reference numeral 612, a process / shortening may be used to limit the number of sets of droplet combinations to be evaluated, such as instead of considering “all” possible droplet combinations for each nozzle, the method may utilize the nozzles. Combinations comprising less than half (or another nozzle quantity, such as ¼), combinations from which more than half of the droplets come from any particular nozzle-waveform, or a high deviation of droplet volume or simultaneous application between target areas. It can be configured to selectively exclude combinations that exhibit large variations in droplet volume. Other metrics can also be used.

Under any limit on the number of sets to be calculated / considered, the method begins to calculate and consider the allowed droplet combinations (613). As indicated by reference numerals 614 and 615, various processes may be used to plan the scanning and / or to effectively select a particular set of droplet volumes per target area TR. For example, as mentioned above, one method assumes a scan path (e.g., selects a particular geometric step) and then considers the maximum value of the minimum residual set selection for all the TRs considered. It is advantageous to weight these scan paths (alternatively geometric steps) that maximize the ability to continue the scan to cover multiple target areas at once. Alternatively or additionally, the method can advantageously weight geometric steps that maximize the number of nozzles used at one time, and reiterate the simplified five-nozzle description mentioned above, in one pass. The scan may be weighted more advantageously for a scan that applies five nozzles to the target area than a scan or pass that will only spray three nozzles. Thus, in one embodiment, the following algorithm may be applied by software:

In this exemplary equation, "i" represents a particular selection of geometric steps or scan paths, w ₁ represents one empirically determined weight, w ₂ represents another empirically determined weight, and #RemCombs _{TR, i} Represents the number of remaining combinations per target area assuming scan path i, and # Simult.Nozzles _i represents a measure of the number of nozzles used for scan path i, which latter need not be an integer, e.g. TR If the sugar filling value changes (eg, to hide artifacts that are likely to be seen on the display device), the particular scan path may be characterized by a variable number of nozzles used per target area column, for example, average or that night. Any other measure of may be used. These coefficients and weights are exemplary only, that is, it is possible to use several other weights and / or considerations other than these, use only one variable without using the other, or use a completely different algorithm.

6A also shows a plurality of further options. For example, in one implementation, consideration of the droplet set is performed 617 in accordance with the equation / algorithm. The comparison metric can be expressed as a score that can be calculated for each possible alternative geometric step to select a specific step or offset. For example, another possible algorithmic approach involves an equation with three terms that appear as follows:

The terms based on S _v , S _e and S _d are calculated here for the variation of the deposited droplet volume, the efficiency (the maximum nozzle used per pass) and the deviation of the geometric step, respectively. In one formula, the term "(S _{v, min} / S _v )" finds the minimum deviation of the fill volume from the target value per pass that depends on the total number of droplets.

Reference numeral 619 of FIG. 6A illustrates, in one embodiment, droplet combination using matrix mathematics, for example, taking into account all droplet volume combinations simultaneously and selecting a scan path using a form of eigenvector analysis. Indicates that selection can be performed.

As indicated by reference numeral 621, an iterative process may be applied to reduce the number of droplet combinations considered. That is, for example, as shown in the above description of one possible technique, the geometric steps may be calculated one at a time. Each time a specific scan path is planned, the method determines the incremental volume still required in each target area under consideration, and then generates a cumulative volume or fill volume per target area that is within the desired tolerances. The most suitable scan or geometric offset can be determined. This process can then be repeated as each iteration until all scan paths and nozzle spray patterns are planned.

The use of a hybrid process is also possible (622). For example, in one embodiment, the first set of one or more scans or geometric steps is based, for example, on the basis of minimized shift and maximum efficiency of droplet volume per nozzle (eg, nozzles used per scan). Can be selected and used. For example, if one, two, three or more specific number of scans are applied, different algorithms may be invoked that maximize the nozzles used per scan, for example, regardless of the variation in the droplet volume applied. Any of the above-mentioned specific equations or techniques (or another technique) may optionally be one of the algorithms applied in this hybrid process, and other variations will be apparent to those skilled in the art.

As mentioned above, in one exemplary display fabrication process, randomization may be planned in which the fill volume per target area is intentionally injected to mitigate the line effect (623). In one embodiment, generator function 625 may optionally be applied to intentionally change the target fill volume in a manner that achieves this planned randomization or other effect (or to a combination of droplets for each target area). The cumulative volume generated for the device may be skewed). As mentioned above, in other embodiments, this deviation may be considered in the target fill volume and tolerance, i.e., even before droplet combinations are analyzed, for example, by applying an algorithmic approach as mentioned above to target It is possible to be considered to meet the charging requirements per area. As discussed below in conjunction with FIG. 8, the development of droplet measurements (and per nozzle, per wave, distribution) that takes into account randomization, such as probability distribution, and relies on this randomization in a calculated manner to meet synthetic fill tolerances. It is also possible. For example, if the randomization of the planned fill is normally variable between ± 0.2% of the target composite fill and the specified tolerance is ± 0.5% of the target composite fill, then the droplet measurement for each nozzle and each nozzle-waveform combination is targeted It can be planned to produce a 3σ value for each nozzle / nozzle-waveform that is within 0.3% (0.2% + 0.3% = 0.5%) of.

6B and 631 refer to a more detailed block diagram associated with the aforementioned repeating droplet combination selection process. As indicated by reference numerals 633 and 635, for the evaluation by software, firstly appropriately possible droplet combinations are once again identified, stored and recalled. For each possible scan path (or geometric step), at reference numeral 637, the method stores a footprint identifying the scan path 639 and nozzles to which it applies, and from the set 641 per target area nozzles. Sugar spraying can be excluded to determine the remaining combination for each target region 643. These are also stored. Then at reference numeral 645, the method evaluates the stored data according to designation criteria. For example, as indicated by the optional (dashed) block 647, the method of maximizing the minimum number of droplet combinations across all relevant target areas is superior to the alternative previously considered alternatives or You can assign a score indicating whether you are poor. If certain criteria are met (645), as indicated by reference numerals 649 and 651, the remaining combinations may be stored or otherwise flagged for use in view of another printhead / substrate scan or pass. Scan or geometric steps can be selected. If the criteria are not met (or the combination is not complete), another step may be considered and / or the consideration of the geometric step (or previously selected step) in which the method is considered may be adjusted (653). In other words, various modifications are possible.

It was mentioned earlier that the order in which the scans are performed or the droplets deposited is not critical for the ultimate synthetic fill value for each target region. This is true, but in order to maximize print speed and throughput, it is desirable that the scans be ordered to produce the fastest or most efficient print possible. Thus, if not already taken into account in geometric step analysis, the sorting or ordering of scans or steps may be performed. This process is shown in Figure 6c.

In particular, reference numeral 661 is used to generally indicate the method of FIG. 6C. By software, such as software running on a suitable machine, the processor may cause the selected nozzle to be driven by two or more injection waveforms (and in some cases, a particular nozzle to identify a selected geometric step, a particular set, or a selected scan path). In these embodiments, a nozzle spray pattern, which may further include data specifying which of the plurality of spray waveforms will be used, for each droplet (663). These steps or scans are then sorted or ordered in such a way as to minimize the incremental step distance. For example, referring back to the hypothetical example mentioned above, if the selected step / scan path is {0, +3, -2, +6 and -4}, each incremental step is minimized and traversed by the motion system. They can be reordered to minimize the overall (cumulative) distance that they become. For example, without reordering, the incremental distance between these offsets would be equivalent to 3, 2, 6, and 4 (so that the cumulative distance traversed in this example is "15"). Scans (eg, scans “a”, “b”, “c”, “d” and “e”) are described in the manner described (eg, “a”, “c”, “b”, “e” and “d”). If reordered, the incremental distance will be +1, +2, 0 and +4 (so that the cumulative distance traversed is "7"). As indicated by reference numeral 667, the method may then assign motion to the printhead motion system and / or substrate motion system, and reverse the order of nozzle ejection (eg, as shown in FIG. 3B). At numbers 339 and 340, when alternating, the circular scan path direction is used). As mentioned above and represented by optional process block 669, in some embodiments, planning and / or optimization may be performed on a subset of target areas, and then the solution is spatially repeated over a large substrate. Is applied.

This repetition is shown in part in FIG. 6D. As represented by FIG. 6D, it should be assumed in this description to manufacture an array of flat panel devices. A common substrate is shown by reference number 681, and a set of dashed boxes, such as box 683, represents the geometry for each flat panel device. Preferably, a reference point 685 having two-dimensional properties can be formed and used on the substrate to locate and align the various manufacturing processes. After completion of these processes, each panel 683 will be separated from the common substrate using a cutting or similar process. If the array of panels represents a respective OLED display, generally the common substrate 681 will be glass, the structure is deposited on the glass, and then one or more encapsulation layers are deposited, and then the glass substrate is the emitting surface of the display. Each panel will be reversed to form a. In some applications, other substrate materials may be used, such as flexible or transparent or opaque materials. As mentioned above, various types of devices can be fabricated in accordance with the described techniques. The solution may be calculated for a particular subset 687 of flat panel 683. This solution can then be repeated for other similarly sized subsets 689 of flat panel 683, and then the entire set of solutions can be repeated for each panel to be formed from a particular substrate.

Reflecting the various techniques and considerations introduced above, manufacturing processes can be performed to mass produce products quickly and at low unit costs. When applied to the manufacture of display devices, such as flat panel displays, these techniques allow for a high speed per-panel printing process and multiple panels can be produced from a common substrate. By providing fast and repeatable printing techniques (eg, using common ink and printheads between panels), for example, ensuring that the fill volume per target area is within specification, layer-by-layer printing times can be avoided without the technique of the present invention. By reducing the fraction of time that would have been required, it is believed that printing can be substantially improved. Returning to the example of a large HD television display, each color component layer can be accurately and reliably printed in less than 180 seconds or even less than 90 seconds for a large substrate (e.g., a 8.5 generation substrate that is approximately 220 cm x 250 cm). This represents a significant process improvement. Improving the efficiency and quality of printing promotes a significant reduction in the cost of producing large HD television displays and thus lower end consumer costs. As mentioned above, display fabrication (particularly OLED fabrication) is one application of the techniques introduced herein, but these techniques can be applied to a variety of processes, computers, printers, software, manufacturing equipment and end devices, and display panels It is not limited to.

One advantage of the ability to deposit precise target area volumes (eg, well volumes) within tolerances is that, as previously mentioned, injects intentional deviations within tolerances. These techniques facilitate the substantial quality improvement of the display by concealing the pixelated artifacts of the display and allowing such "line effects" to be rendered invisible to the naked eye. 7 provides a block diagram 701 associated with one method for injecting this deviation. As in the various methods and block diagrams mentioned above, the block diagram 701 and related methods may optionally be implemented as software on a standalone medium or on a portion of a larger machine.

As indicated by reference numeral 703, the deviation may be made in accordance with a particular frequency reference. For example, the sensitivity of the human eye to contrast deviations is generally a function of brightness, expected viewing distance, display resolution, color and other factors. As part of the stated criterion, given the sensitivity of a typical human eye to the spatial variation of contrast between colors at different brightness levels, such deviation is smoothed in a way that is not perceived by the human eye, such as Means are used to ensure that, under expected viewing conditions, (a) in any directions, or (b) it does not create a human observable pattern between the color components. Optionally, as mentioned above, this can be done using the planned randomization function. Once the minimum criterion is specified, the target fill volume for each color component and each pixel can be intentionally changed in a manner that is calculated to hide any visible artifacts in the human eye (705). The right side of FIG. 7 shows various process options, for example, that the deviation can be made independent of the color component (707), wherein a test for perceptible patterns is applied based on an algorithm so that the filling deviation is perceptible. It can be ensured that no pattern is generated. As indicated by reference numeral 707, for any particular color component (eg, any particular ink), a deviation may be made independently of each of a plurality of spatial dimensions, such as the x and y dimensions, respectively (709). ). In other words, in one embodiment, the deviations are not only smoothed for each dimension / color component, but any pattern of difference between each of these dimensions can also be suppressed and made invisible. In reference numeral 711, for example, by assigning a minor target fill deviation to the filling of each target region prior to droplet volume analysis using any desired criteria, the generator function or functions may be applied to ensure that these criteria are met. . As indicated by reference numeral 713, in one embodiment, as an option, the deviation may be made to be random.

In reference numeral 715, the selection of specific droplet combinations for each target area is thus weighted advantageously to the selected deviation criteria. As mentioned above, this may be done via target fill variation or upon selecting droplets (eg, scan paths, nozzle-waveform combinations, or both). There is another way to impart this deviation as well. For example, in one contemplated embodiment, at 717, the scan path is changed in a non-linear fashion, effectively changing the droplet volume over the average scan path direction. In reference numeral 719, for example, a minor droplet volume deviation can be provided by adjusting the injection pulse rise time, fall time, voltage, pulse width, or by using multiple signal levels per pulse (or other form of pulse shaping technique). By this, the nozzle injection pattern can be changed, and in one embodiment, these deviations can be calculated in advance, and in other embodiments, only waveform deviations are used that produce very minor volume deviations, where the cumulative filling amount is specified tolerance. Other means to ensure that they are within range can be used. In one embodiment, for each target region, a plurality of droplet combinations within a specified tolerance range are calculated and for each target region the selection of which droplet combination is used within the target region (eg, By changing randomly or based on a mathematical function, or by varying a particular waveform (i.e., used to produce a given volume of droplets) for one nozzle that contributes to a selected combination that provides, for example, some volume variation. This effectively changes the droplet volume between the target regions but does not change the planned scan path. Such deviation may be implemented along the scan path direction on one row of the target area, one column of the target area, or both.

8A-8B are used to illustrate a method for developing a statistical model used to evaluate the droplets generated by each nozzle or nozzle-waveform combination, optionally selecting combinations of a plurality of droplets according to statistical averages determined from measurements. Used to describe the method for developing statistical models used for planning. In the example of FIGS. 8A-8B, statistical models are developed for droplet volumes that can be expected from a given nozzle-drive waveform pairing, while in alternative embodiments, similar statistical models can be used for droplet velocity, droplet flight trajectory (eg, vertically). ) Or any other parameter.

The method shown by FIG. 8 is generally indicated by reference numeral 801. For functional block 803, the method in this embodiment begins with the formation of a maximum and minimum fill range for a given range, such as a given target area to receive ink. In the examples presented previously, the specification range may be expressed as a specific value of average plus or minus (eg, 50.00 pL ± 0.5%), but a nearly acceptable range or representation of values may be used. In one contemplated embodiment, the tolerance specified for the target is ± 0.5%, but other values such as 1.0% or 2.0% may be used without limitation. In the same context as the previous example, for these examples, the target is 50.00 pL and the tolerance is ± 0.5% (and therefore the acceptable range is 49.75 pL-50.25 pL), but almost any range or acceptance criterion may be used. have.

For reference numeral 805, one or more candidate waveforms are selected for each nozzle of the printhead or printhead assembly. In embodiments using only a single drive waveform (eg, a fixed voltage square voltage pulse), no selection needs to be performed. In embodiments that allow for tailored waveform formation (discussed below with respect to FIGS. 14B and 15A-B), it is typically desirable to evaluate several selectable waveforms representing a range of values (eg, each under consideration). For the nozzle of, may ultimately be interpolated between the identified plurality of acceptable waveforms). This selection is a manual design process 807 (ie, using waveforms selected by the designer and pre-programming into the system).

With one or more waveforms defined for each nozzle, droplet measurements are planned for various droplet ejections for a given nozzle-waveform pairing. For example, in one embodiment, a plurality of droplets (eg, “24”) may be required for each nozzle, which provides the basis for the evaluation of the measured statistical distribution for the various droplets. Droplet measurement devices (eg, imaging or non-imaging) may be used for this purpose, as discussed herein. Twenty-four (or other numbers) measurements can be planned for one measurement, or for each or multiple measurement cycles or repetitions. Moreover, in one embodiment, the threshold number of measurements can be planned for initialization into the system, and by increasing the measurement dataset over time, a strong confidence in the measured statistical distribution can be developed, in an alternative embodiment. Each measurement may be planned for a moving window of time (e.g., "every 3 hours" a remeasurement may be planned, or the measurement data may only be for any limited time interval used for analysis). In one embodiment, each measurement may be stored as a time stamp, indicating the validity and due date of the measurement during evaluation. Whenever either measurement and / or measurement retention criteria are used, the number of measurements may be planned for each nozzle-waveform pairing for statistical analysis (811). Preferably, the respective measurements for the droplets due to each nozzle-waveform pairing are grouped as a set, known as well-understood rules for mathematical processing (including accumulation) and helping to develop common distribution formats. This can be For example, in order to predict the cumulative or composite distribution of the filling volume resulting from the combination of droplets (for each nozzle-waveform pairing), the relevant parameters that can be combined according to known mathematical processes can be combined with those of normal students. Both T and prioma distributions may have. Thus, in order to achieve accurate filling within specified tolerances with very high reliability (eg, for reference number 813, typically greater than 99% confidence), a statistical combination of droplets potentially associated with different nozzle-waveform pairings is employed. In order to develop an acceptable droplet dataset, the measurement plan can be performed according to the techniques described herein. Thus, in one embodiment of the described technique, the droplet measurement for each nozzle-waveform combination is a known probability distribution type (e.g., in the case of a normal distribution, measurement or number of members n, statistical mean μ and standard). It is planned to satisfy a set of parameters describing the deviation σ), and the measurement data (obtained) is stored for all possible nozzle and nozzle waveform pairings under consideration. In one embodiment, the planning and measurement can be repeated, i.e., the minimum number of primitive measurements (n), the minimum number of measurements satisfying a certain criterion, the minimum statistical spread (e.g., satisfying any criterion or desired confidence interval) Can be repeated until some desired criterion is reached. Whenever planning is applied (eg, by software), a system comprising a droplet measurement device and a printhead assembly under consideration makes droplet measurements, each nozzle (and each drive waveform for a given nozzle). Are individually applied to express a statistically significant number of droplet measurements (815). As indicated by reference numerals 817 and 819, this measurement is optionally performed in place (eg, in a press or in an OLED device manufacturing apparatus, under an optionally controlled atmosphere) and is a sufficient way to develop statistical reliability. . The collected data is then stored in a cumulative probability distribution 821 and / or optionally maintaining individual-measurement data (including, for example, any time stamp used to window the measurement per nozzle). Stored as.

As noted previously, in one embodiment, droplets from potentially-different nozzles and / or nozzle-drive-waves are intelligently combined to obtain accurate filling within high statistical reliability. With a common form of probability distribution formed for each nozzle, these combinations (and related schemes) are statistically correlated to the respective droplets in order to obtain an accurate fill (and a well-understood probability distribution for each fill). It works by combining parameters. This is represented by 823, 825 and 827 of FIG. 8A. More specifically, in one embodiment the droplet averages (eg, corresponding to the associated normal distribution) are combined to obtain the predicted cumulative filling for the target area. As an example, for a given first and second nozzle-waveform pairing, if the average droplet volume is measured at 9.98 pL and 10.03 pL, respectively, the average cumulative filling based on one droplet associated with each pairing is expected to be 20.01 pL ( μ _c = μ ₁ + μ ₂ , where the normal distribution is related), in the same hypothetical example, the standard deviation is 0.032pL (σ ₁ ) and 0.035pL (σ ₂ ) for each droplet, and the expected standard of lurking The deviation is 0.0474 pL (ie, based on σ ² _c = σ ² ₁ + σ ² ₂ ), the 3σ value of the cumulative is approximately 0.142 pL (1σ is equivalent to a confidence interval of approximately 68.27%, and 3σ is approximately 99.73 Equal to% confidence interval). A similar technique can be applied to any common distribution format through the processing of droplet measurement for each nozzle-waveform pairing independent of random variables. Thus, the technique used herein uses a droplet measurement technique to form a statistical model for each nozzle-waveform pairing and, as indicated by box 825, to accumulate random variables (in the case of normal distributions). Plan for a variety of droplet combinations based on the analysis. Nearly any distribution type can be used, and a probability distribution type is provided that conforms to the random variable accumulation. As indicated by functional block 827, in view of the desired specification range (eg, 0.5% of the target), the proposed combination is analyzed (eg, by software) so that the proposed combination is desired with high statistical confidence. To ensure that the range is satisfied. For example, in one embodiment, as mentioned, the desired reliability criterion (eg, 3σ representing a confidence interval of 99.73%) is tested to ensure that it fits within the desired tolerance range. As an example, if the desired tolerance was 49.75-50.25pL for the example introduced above, the possible droplet combinations resulted in an average of 3σ and 49.89pL equal to 0.07pL, 99% that the cumulative filling would lie between 49.82pL and 49.96pL. It is interpreted as reliability, which is within the desired tolerance range, and the particular combination will be considered an acceptable combination (for the droplet combination analysis function described above). In other words, any desired statistical criterion or beneficial portion of the fit data can be used, in another embodiment a 4σ value (99.993666%) or other value is analyzed for the desired tolerance range. With acceptable droplet combinations that are well determined for each printing well, the specific combination of droplets for each well, indicating that they are deposited simultaneously by multiple nozzles of the printhead assembly, is printed according to the planned droplet combination for each well. Subsequent to 829, it is planned (see FIGS. 5-7).

FIG. 8B provides another method 851 to allow for intentional target area fill variation and optionally a method for performing a variable number of droplet measurements per nozzle (or per nozzle-waveform) according to a desired criterion. . More specifically, the method may be executed once again as instructions stored on a non-transitory machine-leadable medium that controls at least one processor for performing a set of functions indicated by the instructions. The desired tolerance range is received, for example with the first operator "x" for reference number 853, and it should be specified that the target area (eg pixel well) must be within a given percentage of the target volume (eg 50.00 pL ± 0.5%). Can be. This tolerance range can be indicated by customer or industry specifications, as indicated by function 855. If you want to plan for the intended deviation of the composite volume (for example, random deviation within a small range to avoid line effects or other noticeable artifacts in the finished display), for function 857, the range is the second operator. received as "y". Based on these two operators, the method calculates a valid and acceptable maximum variance, standard deviation, or other measure for block 859. In one embodiment, y is subtracted from x as shown in the figure and is equal to the validly allowed charge deviation, e.g., if the specification requires a charge within ± 0.5% for the above example, The intended random deviation of is injected into the planned composite mean for the well filling (eg 49.95 pL-50-05 pL) so that the allowed deviation (before the random deviation) is again 49.80 using an example of a target of 50.00 pL ± 0.5%. It may be limited to pL-50.20pL. In addition, instead of simply subtracting these measurements, for example, another set of limit criteria may be used, such as based on mathematics relating to a statistical combination of standard deviations or variances for independent random variables, Many other criteria can be applied according to embodiments. For block 859, the remaining range (e.g., ± 0.4% of the target) may be equal to the desired confidence interval (e.g., 3σ interval or statistical measurement), and if possible droplet combinations are acceptable, or for the examples given above. It can be used to assess whether it is excluded from consideration.

Alternatively, as indicated by functional blocks 861 and 863, the remaining range and associated confidence intervals may be applied as a criterion governing droplet measurement to form a desired statistical model for each droplet. For example, as represented by block 861, with a defined desired confidence interval (eg, 3σ <= 0.4% of the target), the desired variance or the maximum allowed variance can be identified and meets the desired statistical criteria. It effectively forms the baseline number n of droplet measurements that needs to be taken for each nozzle-waveform combination in a calculated manner to produce a statistical model. For example, whether the filling is intentionally variable or not, the desired effective tolerance range can be used to identify a plurality of measurements (eg, 24, 50 or another number) calculated to produce a tight statistical distribution, which is printed. This leads to a large number of possible droplet combinations that can be used for planning. This calculation can be applied in a number of ways, such as (a) identifying the threshold number of measurements applied for each nozzle-waveform combination (eg, 24 droplet measurements for each), or (b) each Identify the threshold statistical criteria that must be met for the nozzle-waveform combination (eg, a measure of the potentially-variable number performed for a nozzle or nozzle-waveform up to threshold criteria such as variance, standard deviation, etc.). With various exemplary functions represented by the test set presented by function box 865, a drop test function is applied 863 using a droplet measurement device to perform the measurement. For example, a droplet of n _i may be measured for each nozzle (or nozzle-waveform pairing) “i”, as indicated in box 865. For each measurement, the software controlling the droplet measurement device can perform incremental droplet volume measurement 867 and store 869 the data in memory. After each measurement (or after the measurement of the number of thresholds), the overall measurements for a given nozzle-waveform combination accumulate so that statistical parameters (e.g., average, standard deviation for a normal distribution type) for a particular nozzle-waveform combination , μ, and σ) can be calculated (871). These values can be stored 873 in memory. Optionally, for function box 874, these same or different measurement techniques are applied to store the velocity v and one or more droplet measurements for the x and y dimensional trajectories α and β. As indicated by reference numeral 875, a decision criterion may be applied to determine if sufficient measurements have been taken for a given parameter (eg, volume) for a particular nozzle-waveform combination (i), or if additional measurements are desired. If further measurements are needed, the method may be cycled to flow arrow 877 to make these additional measurements, ie, a statistical model can be formed for a particular nozzle-waveform combination that meets the desired robustness criteria. If no further measurements are needed, the method proceeds to the next nozzle (879) and is properly circulated for flow arrow 881 until all nozzles and / or nozzle-waveform combinations have proceeded. This order is not required for all embodiments, for example, the loops 877 and 881 may be reversed, for example, as droplet measurements are performed on each nozzle in succession, such a process yields robust data. Repeated until loss, this process provides certain advantages in a stacked manner over other system processes (eg, see discussion below in FIG. 19), for example for embodiments where the drop measurement is performed with increasing. Once all nozzles or nozzle-waveform combinations have been sufficiently tested, for reference numeral 883, the method temporarily suspends when executed on an end or intermittent basis. For the described droplet testing, the obtained data, including measured data and / or calculated statistical parameters, are discussed in the machine-leadable memory 885 for use in, for example, droplet combination schemes, as discussed above. Stored. In addition, the data obtained may optionally be used in other ways instead of or in addition to intelligent mixing of different droplet volumes. In one embodiment, as mentioned, the stored data refers to any desired droplet parameter, that is, in the form of individual measurement and / or statistical parameters, including one or more droplet volumes, droplet volumes and / or droplet trajectories. Can be represented.

9A-10C are used to provide simulation data for the techniques mentioned herein. 9A-9C show expected synthetic fill volumes based on five droplets, while FIGS. 10A-10C show expected synthetic fill volumes based on ten droplets. For each of these figures, the indicator " A " (e.g., Figures 9A and 10A) indicates the situation where a nozzle is used to deposit droplets without accounting for volume differences. In contrast, the indicator “B” (eg, FIGS. 9B and 10B) represents a situation where a random combination of (5 or 10) droplets is selected to “average” the expected volume difference between the nozzles. Finally, the indicator " C " (e.g., Figures 9C and 10C) represents a situation where scan and nozzle injection depend on the specific cumulative ink volume per target area to minimize cumulative charge dispersion between the target areas. In these various figures, it is assumed that the deviation per nozzle is consistent with the deviation observed in the actual device, each vertical axis representing the cumulative filling volume in pL, and each horizontal axis representing the target area, eg pixel well or pixel. The number of color components is shown. The emphasis in these figures is to show the deviation in the cumulative filling volume, assuming a randomly distributed droplet variation with respect to the hypothesized mean. 9A-9C, the average volume per nozzle is slightly less than 10.00 pL per nozzle, and for FIGS. 10A-10C it is assumed that the average droplet volume per nozzle is slightly greater than 10.00 pL per nozzle.

The first graph 901 shown in FIG. 9A shows the volume deviation per well assuming a difference in nozzle droplet volume when no attempt is made to mitigate these differences. These deviations may be extremes (eg, peaks 903) with a range of cumulative fill volumes of about ± 2.61%. As mentioned, the average of the five droplets is slightly lower than 50.00 pL, and FIG. 9A shows two sets of sample tolerance ranges centering on this average, with the first range 905 centering this value. Has a range of ± 1.00%, and the second range 907 represents a range of ± 0.50% having this value at the center. As indicated by the various peaks and troughs (e.g., 903) out of range, such a printing process is required to meet specifications (e.g., one or the other of these ranges). Draw many wells that will fail.

The second graph 911 shown in FIG. 9B shows the volume variation per well using a randomized set of five nozzles per well to statistically average the effect of droplet volume variation. This technique does not allow for the precise production of a certain volume of ink in any particular well, nor does this guarantee that the cumulative volume is within range. For example, although a percentage of fill volume outside the specification represents a case that is much better than that represented by FIG. 9A, an individual well (eg, the well identified by low point 913) is a specification, such as a drawing number ( There is still a situation outside the ± 1.00% and ± 0.50% deviations indicated by 905 and 907 respectively. In this case, the minimum / maximum error is ± 1.01%, reflecting the improvement by random mixing compared to the data presented in FIG. 9A.

9C shows a third case using a particular combination of droplets per nozzle according to the above technique. In particular, graph 921 shows that the deviation is entirely within the ± 1.00% range and nearly satisfies the ± 0.50% range for all appearing target areas, which, in other words, are indicated in reference numerals 905 and 907, respectively. Appear by In this example, five specifically selected droplet volumes may be used to fill the wells in each scan line, with the printhead / substrate shifted appropriately for each pass or scan. The minimum / maximum error is ± 0.595%, which reflects a further improvement by this type of "smart mixing". Improvements and data observations are consistent for any form of intelligent droplet volume combination, so that a specific fill amount or tolerance range can be obtained, such as where offsets between nozzle rows (or multiple printheads) are used, or multiple dictionary The selected drive waveform can be used to allow a combination of specifically selected droplet volumes.

As mentioned above, FIGS. 10A-10C show similar data, but with an average droplet volume of about 10.30 pL per nozzle, assuming a combination of 10 droplets per well. In particular, the graph 1001 of FIG. 10A illustrates the case where no attention is paid to alleviating the droplet volume difference, and the graph 1011 of FIG. 10B illustrates the application of droplets randomly to statistically “average” the volume difference. The graph 1021 of FIG. 10C illustrates the case of the planned mixing of specific droplets (to obtain the average fill volume of FIGS. 10A / 10B, ie, approximately 103.10 pL). These various figures show tolerance ranges of ± 1.00% and ± 0.50% deviations from this mean, indicated using range arrows 1005 and 1007, respectively. Each of the figures further shows respective vertices 1003, 1013 and 1023 represented by the deviation. However, FIG. 10A shows a ± 2.27% deviation in the target, FIG. 10B shows a ± 0.707% deviation in the target, and FIG. 10C shows a ± 0.447% deviation in the target. When averaging a larger number of droplets, the “random droplet” solution of FIG. 10B is shown to obtain a ± 1.00% tolerance range from the average rather than the ± 0.50% range. In contrast, the solution of FIG. 10C appears to meet both tolerance ranges, demonstrating that the deviation can be limited to within specification while still allowing for a variation in droplet combination between wells.

One optional embodiment of the techniques described herein is as follows. For printing processes where nozzles with a droplet volume standard deviation of x% are used to deposit a cumulative filling volume with a maximum deviation of ± y%, the conventional method ensures that the cumulative filling volume will vary by ± y%. There is little means. This presents a potential problem. Droplet averaging techniques (such as those represented by the data shown in FIGS. 9B and 10B) statistically reduce the standard deviation of the cumulative volume between target regions to x% / (n) ^1/2 , where n is the desired fill volume. Is the average number of droplets required per target area to obtain. However, even by this statistical approach, there is in fact no means to reliably ensure that the actual target area fill volume will be within the maximum error range tolerance of ± y%, especially if y and n are small. The technique referred to herein provides a means of providing this reliability by ensuring a known percentage of the target area and achieves synthetic filling within ± y%. Thus, one optional embodiment provides a method of generating control data or controlling a printer, and a standard deviation of volume between the associated apparatus, system, software, and target areas that is better than x% / (n) ^1/2 (eg, x improvement significantly better than% / (n) ^1/2 ). In certain embodiments, this condition is met under an environment where printhead nozzles are used simultaneously to deposit droplets into each target area row (eg, each pixel well) by each scan.

A set of basic techniques for combining droplets such that the sum of droplet volumes is specifically selected to meet a particular target has been described, and the present specification now provides a more detailed description of specific devices and applications that can benefit from these principles. Will provide. This description is intended to describe non-limiting, that is, some embodiments specifically contemplated for carrying out the aforementioned method.

As shown in FIG. 11, the multi-chamber fabrication apparatus 1101 includes several general modules or subsystems, such as a transfer module 1103, a printing module 1105, and a processing module 1107. Each module maintains a controlled environment, such that printing is performed by printing module 1105 in a first controlled atmosphere, and other processing, such as another deposition process, such as inorganic encapsulation The layer deposition or curing process (eg, curing of the printed material) can be performed in a second controlled atmosphere. The apparatus 1101 uses one or more mechanical handlers to move the substrate between modules without exposing the substrate to an uncontrolled atmosphere. Within any particular module, it is possible to use other substrate handling systems and / or specific devices and control systems suitable for the processing to be performed on the modules.

Various embodiments of the transfer module 1103 include an input loadlock 1109 (ie, a chamber that provides buffering between different environments while maintaining a controlled atmosphere), transfer (with a handler to transfer the substrate). A chamber 1111, and an atmospheric buffer chamber 1113. Within the printing module 1105 it is possible to use other substrate handling means, such as a floatation table for stable support of the substrate during the printing process. In addition, an xyz-motion system such as a split axis or gantry motion system (support motion system) can be used for precise positioning of the at least one printhead relative to the substrate, and also provides a print module 1105. A y-axis transport system can be provided for the transfer of the substrate through. It is also possible to use a plurality of inks to print with their respective printhead assemblies in the printing chamber, so that for example two different types of deposition processes can be performed in the printing module in one control atmosphere. The printing module 1105 may include a gas enclosure 1115 housing an inkjet printing system, and introduce an inert atmosphere (eg, nitrogen, noble gas, another similar gas, or a combination thereof). Means for controlling the atmosphere, gas constituency and particle presence for environmental conditioning (eg, temperature and pressure) in other ways.

The processing module 1107 may include, for example, a transfer chamber 1116, which may further have a handler for transferring the substrate. In addition, the processing module may further include an output load lock 1117, a nitrogen stack buffer 1119, and a curing chamber 1121. In some applications, a curing chamber can be used to cure the monomer film into a uniform polymer film, such as using a thermal or UV radiation curing process.

In one application, the apparatus 1101 is suitable for mass production of a liquid crystal display screen or an OLED display screen, such as for producing an array of eight screens at a time on one large substrate. These screens can be used for televisions and as display screens of other forms of electronic devices. In a second application, the device can be used in the same way for mass production of solar panels.

When applied to the droplet-volume combination techniques described above, the printing module 1105 is used in display panel manufacture to provide one or more layers such as light filtering layers, light emitting layers, barrier layers, conductive layers, organic or inorganic layers, encapsulation layers and Other types of materials can be deposited. For example, various chambers may be mounted in the depicted apparatus 1101 to deposit and / or cure or harden one or more printed layers in a manner that is not hindered by intermediate exposure to an uncontrolled atmosphere. It can be controlled to move the substrate reciprocally in the liver. Optionally, ink droplet measurement (when used with the system shown) can be performed while the substrate is being moved or processed in any chamber. For example, the first substrate may be loaded via an input loadlock 1109, during which process the printhead assembly in the print module 1105 is connected with a droplet measurement device to measure droplets for a subset of print nozzles. And in embodiments with many printing nozzles, droplet measurement can be periodic and intermittent, so that within various printing cycles, different nozzles representing a circular-progressive subset of all nozzles of the printing assembly are calibrated, Associated droplets are measured to develop a statistical model for each droplet volume, ejection angle (vertical) and velocity. A handler located within the transfer module 1103 may move the first substrate from the input loadlock 1109 to the printing module 1105, where the droplet measurement is separated and the printhead assembly is printing active. Is moved to the position for After the printing process is completed, the first substrate is moved to the processing module 1107 for curing. Once again, a new cycle of droplet measurement can be performed, with the second substrate optionally loaded into the input loadlock 1109 (if supported by the system). Many other alternatives and process combinations are possible. By repeated deposition of subsequent layers, such as by reciprocating the first substrate for repeating printing and curing, each volume controlled for the target area, cumulative layer properties, is suited for any desired application. Can be formed. In alternative embodiments, output load lock 1117 may be used to transfer the first substrate to a second printing press (eg, a new layer, such as a new layer of OLED material or an encapsulation or other layer in sequential order, pipes). For lined printing). Note again that the techniques described above are not limited to display panel manufacturing processes, and that various types of tools can be used. For example, the configuration of the device 1101 is variable such that different modules 1103, 1105 and 1107 can be arranged in different parallel, and additional modules or fewer modules can also be used. As indicated by reference numerals 1121 and 1123, a computing device (e.g., a processor) executing suitable software may be used to control various processes and to perform selective droplet measurements simultaneously with other processes, as described above. That is, the device minimizes downtime, maintains a robust statistical model while maintaining the most up-to-date droplet measurement, and stacks droplet measurement processes that overlap with other system processes as much as possible.

11 provides one illustration of a set of connected chambers or fabrication components, but it is apparent that many other possibilities exist. The ink droplet measurement and deposition technique introduced above can be used with the device shown in FIG. 11 and can control the manufacturing process performed by virtually any other type of deposition facility.

12 provides a block diagram illustrating various subsystems of one apparatus that may be used to fabricate a device having one or more layers as specified herein. Coordinates on the various subsystems are provided by processor 1203 operating in accordance with instructions provided by software (not shown in FIG. 12). During the manufacturing process, the processor supplies data to the printhead 1205, which enables the printhead to eject various volumes of ink in accordance with the nozzle ejection instructions provided. The printhead 1205 generally includes a plurality of ink jet nozzles arranged in rows (or rows of arrays), and those that enable jetting of ink in response to activation of piezoelectric or other transducers per nozzle. With this associated reservoir, the transducer can eject a controlled amount of ink in an amount controlled by an electronic nozzle drive waveform signal applied to the corresponding piezoelectric transducer. If there are multiple printheads, there may be a processor for each printhead, or one processor may control the entire printhead assembly. Alternative injection means can also be used. As indicated by the halftone print image, each printhead applies ink at various x-y locations on the substrate 1207 corresponding to the grid coordinates in the various print cells. Positional deviations are affected by both the printhead motion system 1209 and the substrate handling system 1211 (eg, printing may describe one or more swaths across the substrate). In one embodiment, the printhead motion system 1209 moves the printhead (s) back and forth along the traveler, during which the substrate handling system provides stable substrate support and " y " To enable "split-axis" printing of portions of? The substrate handling system provides relatively fast y-dimensional transport, while the printhead motion system 1209 provides relatively slow x-dimensional transport. In yet another embodiment, the substrate handling system 1211 can provide both x- and y-dimensional transport. In yet another embodiment, primary transport may be provided entirely by the substrate handling system 1211. Image capture device 1213 may locate any reference point and assist in alignment and / or error detection.

The apparatus may include an ink delivery system 1215 and a printhead maintenance system 1217 to assist in printing operations. The printhead may be periodically calibrated or subject to maintenance processes. For this purpose, during the maintenance sequence, the printhead maintenance system 1217 may be used to purge the appropriate priming, ink or gas to suit the particular process. purge, test and calibration, and other operations may be performed.

As introduced above, the printing process can be performed in a controlled environment, ie in a manner that provides a reduction in the risk of contamination that can degrade the effectiveness of the deposited layer. To this end, the apparatus includes a chamber control subsystem 1219 that controls the atmosphere in the chamber indicated by the function block 1221. Optional process variations as mentioned may include performing spraying of the deposition material in the presence of an ambient nitrogen gas atmosphere.

As mentioned above, in the embodiments described herein, the individual droplet volumes can be combined to obtain a specific fill volume per target area selected according to the target fill volume. A specific fill volume can be planned for each target area, where the fill value changes within the allowable tolerance range around the target value. In this embodiment, the droplet volume is specifically measured in a manner dependent on ink, nozzles, drive waveforms, and other factors. For this purpose, reference numeral 1223 designates an optional droplet volume measurement system, where droplet volume 1225 is measured for each nozzle and for each drive waveform and then stored in memory 1227. Such droplet measurement systems may be optical strobe cameras or laser scanning devices (or other volumetric tools) embedded in commercial printing devices, as mentioned above. In one embodiment, such a device is a simple alternative to non-imaging techniques (e.g., image processing software acting on a pixel) to achieve measurements of individual droplet volume, deposition flight angle or trajectory, and droplet velocity in real time or near real time. Using an optical detector). This data is provided to the processor (s) 1203 during printing, or during one-time, intermittent or periodic calibration operations. As indicated by reference numeral 1229, a pre-arranged set of spray waveforms may be associated with each nozzle for use later on to produce droplet combinations per particular target area, optionally for such waveforms for embodiments. When a set of s is used, it is preferred that droplet volume measurements are calculated during calibration using the droplet measurement system 1123 for each nozzle during each waveform. Since measurements can be taken as needed and processed (eg, averaged) to minimize statistical volumetric errors, providing a real-time or near-real-time droplet volumetric system provides greater reliability in providing target area volume filling within the desired tolerance range. Is improved.

Reference numeral 1231 denotes the use of print optimization software running on the processor 1203. More specifically, the software, based on the statistical model of droplet volume 1225 (measured in situ or otherwise provided), may use this information to properly obtain a specific fill volume per target area. Printing can be planned by combining droplet volumes. In one embodiment, according to the example mentioned above, although the droplet measurement device may have a lower accuracy than that of individual droplet measurements, the cumulative volume may be planned according to 0.01 pL or better resolution within a certain error tolerance. That is, using the techniques described herein to establish a statistical model of per droplet volume nozzle and per nozzle / waveform combination, the statistical accuracy is inferred from that expressed by the accuracy of the droplet measurement system. Once printing is planned, the processor (s) are used to calculate printing parameters such as the number and sequence of scans, droplet size, relative droplet injection time, and similar information, and to determine nozzle spraying for each scan. Build it. In one embodiment, the print image is a halftone image. In yet another embodiment, the printhead has a plurality of nozzles of 10,000. As will be described below, each droplet may be described according to a time value and an injection value (eg, data describing the injection waveform or data indicating whether the droplet is to be “digitally” injected). . In embodiments where geometric step and binary nozzle jetting determinations are used to change the droplet volume per well, each droplet is defined by bits of data, step values (or number of scans), and position values indicating where the droplets are placed. Can be. In implementations in which the scan represents continuous motion, the time value may be used as corresponding to the position value. Regardless of whether it is based on time / distance or absolute position, the value describes the position relative to a criterion (eg, synchronization mark, position or pulse) that precisely specifies the position and time at which the nozzle should be ejected. In some embodiments, multiple values may be used. For example, in one specifically contemplated embodiment, a synchronization pulse is generated for each nozzle in a manner corresponding to each micron of relative printhead / substrate motion during a scan, and at each synchronization pulse. In this regard, each nozzle has a 4-bit to describe one of the 15 waveform selections preprogrammed with (a) an offset value describing the integer clock cycle delay before the nozzle is ejected, and (b) a memory specific to the particular nozzle driver. A waveform selection signal (ie, one of 16 possible values specifying the “off” or non-injection state of the nozzle), and (c) the nozzle is only once, or once for every synchronization pulse, or every It is programmed by a repeatability value that specifies whether to be fired once every n synchronization pulses. In this case, the waveform selection and address for each nozzle by processor (s) 1203 are associated with specific droplet volume data stored in memory 1227, where the injection of the particular waveform from the particular nozzle is performed on the substrate. Indicate a planned decision that a particular corresponding droplet volume will be used to supply the cumulative ink to a particular target area.

13A-15C will be used to introduce another technique that can be used to precisely combine different droplet volumes within the printhead assembly to obtain in-tolerance fill volumes for each target area. In a first technique, rows of nozzles may be selectively offset relative to each other during printing (eg, between scans). This technique is introduced with reference to FIGS. 13A-13B. In a second technique, nozzle drive waveforms may be used to control piezoelectric transducer injection and thus the properties (eg, volume) of each ejected droplet. 14A-14B are used to illustrate some options. Finally, in one embodiment, a set of a plurality of alternative droplet ejection waveforms is precomputed and made available for use by each print nozzle. This technique and related circuitry are described with reference to FIGS. 15A-C.

13A provides a top view 1301 of a printhead 1303 that traverses the substrate 1305 in the scanning direction indicated by arrow 1307. It is shown herein that the substrate consists of a plurality of pixels 1309, where each pixel has wells 1309-R, 1309-G, and 1309-B associated with its respective color component. This illustration is merely an example, that is, the techniques used herein may be applied to any layer of a display (eg, not limited to individual color components and to color imparting layers), and these techniques may also be used in display devices. It can be used to build something other than. In this case, it is intended for the printhead to deposit one ink at a time, and assuming that the ink is color component-specific, a separate printing process is performed on one of the color components for each well of the display. Will be. Thus, when the first process is being used to deposit ink specific to red light generation, only the first well of each pixel, such as the well 1309 -R of the pixel 1309 and similar wells of the pixel 1311 It will contain the ink in the first printing process. In the second printing process, the second well 1309 -G of the pixel 1309 and similar wells of the pixel 1311 will receive the second ink. The various wells thus appear as arrays of three different overlapping target regions (in this case, fluid reservoirs or wells).

The printhead 1303 includes what is indicated using a plurality of nozzles, such as numbers 1313, 1315 and 1317. In this case, each number refers to a separate row of nozzles, the rows extending along the column axis 1318 of the substrate. The nozzles 1313, 1315, and 1317 appear to form a first nozzle row relative to the substrate 1305, and the nozzle 1329 represents the second nozzle row. As shown by FIG. 13A, the nozzles are not aligned with the pixels and when the printhead traverses the substrate in one scan, some nozzles avoid the target area while other nozzles will not. In addition, in the figures, print nozzles 1313, 1315, and 1317 are precisely aligned to the center of the pixel row starting with pixel 1309, and the print nozzle 1329 will avoid pixel rows starting with pixel 1311. The alignment of the print nozzle 1329 is not accurate at the center of the pixel 1311 and its associated row. This alignment / misalignment of rows of wells and columns of nozzles is shown by lines 1325 and 1327, respectively, which represent the center of the printing well for receiving ink. In many applications, the precise location at which the droplets are deposited in the target area is not critical, and such misalignment can be tolerated (eg, as discussed in connection with FIGS. 1B and 4D, with some groups of multiple nozzles and respective ones). Approximate alignment of rows would be desirable).

FIG. 13B provides another view 1331, where all three nozzle rows (or individual printheads) are rotated by approximately 30 degrees relative to axis 1318. This optional capability was previously referred to by reference numeral 338 in FIG. 3B. More specifically, because of the rotation, the spacing of the nozzles along the thermal axis 1318 has changed and each nozzle row is aligned with the center of the well 1325 and 1327, or otherwise increasing the nozzle apparent density per target area during the scan. To be adjusted. However, because of this rotational and scanning motion 1307, the nozzles from each nozzle row will intersect the pixel rows (e.g., 1309 and 1311) at different relative times and thus potentially generate different positional injection data (e.g., droplets). Different timings for injection). Methods for adjusting the injection data for each nozzle will be discussed below with respect to FIGS. 15A-B.

As shown in FIG. 13C, in one embodiment, a printhead assembly optionally provided with a plurality of printhead or nozzle rows may have these rows selectively offset from each other. That is, FIG. 13C provides another top view, where each printhead (or nozzle row) 1319, 1321, and 1323 are offset relative to each other, as indicated by offset arrows 1353 and 1355. These arrows indicate the use of selective motion means, one for each nozzle row, to enable selective offset of the corresponding row relative to the printhead assembly. This provides different combinations of nozzles (and specific droplet volumes associated with them) by each scan, and thus different specific droplet combinations (eg, 1307). For example, in this embodiment, as shown by FIG. 13C, the offset causes both the nozzles 1313 and 1357 to align with the center line 1325, thus reducing their respective combined droplet volumes in a single pass. Have it. This embodiment is contemplated as a particular embodiment of varying geometric steps, e.g., even if the geometric step size is fixed between successive scans of the printhead assembly 1303 to the substrate 1305. Each such scan motion of a particular nozzle row is effectively located at a variable offset or at a step using motion means for the position. In addition or alternatively, this offset can be performed to adjust the efficient printing grid, providing a variable spacing between the deposited droplets. Consistent with the principle introduced above, the use of an optional offset allows the droplet volume per individual nozzle to accumulate, in particular, combined (or droplet set) for each well, by a reduced number of scans or passes. For example, with the embodiment shown in FIG. 13C, three droplets may be deposited in each target region (eg, well for the red color component) by each scan, and the offset may further be added to the droplet volume and Enable a planned deviation of the spatial combination.

FIG. 13D is a cross-sectional view of the completed display for one well (eg, well 1309-R of FIG. 13A) taken in the scanning direction. In particular, this view shows a substrate 1352 of a flat panel display, such as an OLED device. The cross section shown shows an active region 1353 and a conductive terminal 1355 for receiving electrical signals for controlling the display (eg, the color of each pixel). A small elliptical region 1361 is shown enlarged on the right side of the figure to show a layer of the active region over the substrate 1352. These layers include an anode layer 1369, a hole injection layer (“HIL”) 1372, a hole transport layer (“HTL”) 1373, a light emitting layer (“EML”) 1375, an electron transport layer (“ETL”). 1377 and cathode layer 1378, respectively. Additional layers such as polarizers, barrier layers, primers and other materials may also be included. In some cases, OLED devices may include only a subset of these layers. When the illustrated stack is finally operated after fabrication, recombination of electrons and "holes" can occur in the EML by current flow, leading to emission of light. The anode layer 1369 may include one or more transparent electrodes common to several color components and / or pixels, for example, the anode may be formed of indium tin oxide (ITO). The anode layer 1369 may also be reflective or opaque, and other materials may be used. In general, cathode layer 1378 consists of a patterned electrode to provide selective control of each color component for each pixel. The cathode layer may comprise a reflective metal layer, such as aluminum. The cathode layer may also comprise an opaque layer or a transparent layer, for example a thin metal layer in combination with an ITO layer. The cathode and anode together serve to supply and collect electrons and holes through the OLED stack. In general, the HIL 1371 serves to transport holes from the anode to the HTL. In general, the HTL 1373 plays a role of transporting holes from HIL to EML and also promotes transport of electrons from EML to HTL. In general, the ETL 1377 facilitates the transport of electrons from the EML to the ETL while transporting electrons from the cathode to the EML. These layers can supply electrons and holes together to the EML 1375 and confine these electrons and holes to the layer, thereby recombining them to generate light. In general, EML consists of an active material controlled individually for each of the three primary colors, ie red, green and blue, and in this case by the material generating red light, as mentioned above for each pixel of the display. Are represented.

The layer in the active region can be degraded by exposure to oxygen and / or moisture. Thus, it is desirable to improve OLED life by encapsulating these layers at both the side and sides 1362/1363 as well as at the lateral edges opposite the substrate. The purpose of encapsulation is to provide a barrier against oxygen and / or moisture. Such encapsulation may be formed, at least in part, through the deposition of one or more thin film layers.

The techniques described herein can be used to deposit any of these layers as well as combinations of such layers. Thus, in one contemplated application, the techniques referred to herein provide the ink volume for the EML layer for each of the three primary colors. In another application, the techniques described herein are used to provide ink volume for HIL layers and the like. In another application, the techniques described herein are used to provide ink volume for one or more OLED encapsulation layers. The printing techniques mentioned herein may be used to deposit organic or inorganic layers, and other types of displays and non-display devices, as appropriate for the process technique.

14A is used to introduce nozzle drive waveform adjustment and the use of alternating nozzle drive waveforms to provide different droplet volumes ejected from each nozzle of the printhead. The first waveform 1403 is represented by a single pulse, which is the silent period 1405 (0 volts), the rising slope 1413 associated with the nozzle injection determination at time t ₂ , the voltage pulse or signal level 1407, And the falling slope 1411 at the time point t ₃ . The effective pulse width, represented by reference numeral 1409, has a duration approximately equal to t ₃ -t ₂ , which depends on the difference between the rising and falling slopes of the pulse. In one embodiment, any of these parameters (eg, rising slope, voltage, falling slope, pulse duration) may be changed to change the droplet volume ejection characteristics for a particular nozzle. The second waveform 1423 is similar to the first waveform 1403 except that it exhibits a larger drive voltage 1425 compared to the signal level 1407 of the first waveform 1403. Because of the larger pulse voltage and finite rising slope 1749, it takes longer to reach this higher voltage, and likewise, the falling slope 1429 is generally delayed compared to a similar slope 1411 from the first waveform. The third waveform 1433 is also similar to the first waveform 1403. In this case, different rising slopes 1435 and / or different falling slopes 1437 can be used in place of the slopes 1413 and 1411 (eg, through adjustment of the nozzle injection path impedance). Different slopes may be made steeper or more gentle (if shown, more steep). Alternatively, in the case of the fourth waveform 1443, for example, a pulse is made longer using a delay circuit (eg, a voltage-controlled delay line), so that at a particular signal level (indicated by drawing number 1445), It is possible to increase the time of the pulse of and delay the falling edge of the pulse, as represented by reference numeral 1447. Finally, fifth waveform 1453 illustrates the use of multiple discrete signal levels by providing a means of pulse shaping. For example, this waveform appears to include the time at the first mentioned signal level 1307, but the slope rising to the second signal level 1455 is partially applied between time points t ₃ and t ₂ . Because of the larger voltage, the trailing edge of this waveform 1457 appears to be delayed behind the falling edge 1411.

Any of these techniques can be used in combination with any of the embodiments mentioned herein. For example, after scan motion and nozzle injection have already been planned, drive waveform adjustment techniques can be used to vary the droplet volume within a small range later, to mitigate line effects. Designing the waveform deviation in such a way that the second tolerance is within the specification facilitates the deposition of a high quality layer with a planned non-random or a planned random deviation. For example, referring back to the previous assumption that a television manufacturer specified a filling volume of 50.00 pL ± 0.50%, the filling volume per area could be calculated within a first range of 50.00 pL ± 0.25% (49.785 pL-50.125 pL). Where a non-random or random technique is applied to the waveform deviation and the deviation statistically contributes to a volume deviation of less than ± 0.025 pL per drop (assuming 5 drops are needed to reach the cumulative filling volume). . Alternatively or additionally, drive waveform deviations can be used to affect the velocity or trajectory (flying angle) of the ejected droplets. For example, in one process, droplets are required to meet a predetermined set of criteria for volume and / or velocity and / or trajectory, and if the droplet falls outside the norm for which it is applied, the nozzle waveform is adjusted until it is conformed. Can be. Alternatively, a set of predetermined waveforms can be measured with these subsets of waveforms selected based on matching the desired criteria. It is obvious that several different deviations exist.

As mentioned above, in one embodiment represented by the fifth waveform from FIG. 14A, multiple signal levels may be used to shape the pulse. This technique is mentioned below with reference to FIG. 14B.

That is, in one embodiment, the waveform can be designated, for example, as a sequence of discrete signal levels defined by digital data, where a drive waveform is generated by a digital-to-analog converter (DAC). Reference numerals in FIG. 14B refer to waveforms 1453 having discrete signal levels 1455, 1457, 1459, 1461, 1463, 1465, and 1467. In this embodiment, each nozzle driver includes circuitry for receiving and storing up to 16 different signal waveforms, where each waveform is a series of up to 16 signal levels each represented by a multi-bit voltage and duration. It defines. In other words, in this embodiment, the pulse width can be effectively varied by defining different durations for one or more signal levels, and the drive voltage can be shaped into a waveform selected to provide minor droplet size variations. For example, droplet volume is measured to provide a specific volume gradient increment, eg, in units of 0.10 pL. Thus, in this embodiment, the waveform shaping provides the ability to tailor the droplet volume to be close to the target droplet volume, and when combined with other specific droplet volumes, such as when using the techniques described above, The technique promotes a precise fill volume per target area. However, in addition, these waveform shaping techniques also facilitate strategies for reducing or eliminating line effects, e.g., in one optional embodiment, although a certain volume of droplets are combined as mentioned above, the final droplet (or Droplets) are selected in such a way as to provide a deviation to the boundary of the desired tolerance range. In another embodiment, the waveforms specified by optional additional waveform shaping or timing may be applied to appropriately adjust droplet volume, velocity, and / or trajectory. In another example, the use of nozzle drive waveform alternatives provides a means for planning volume such that no additional waveform shaping is required.

In general, the effects of different drive waveforms and final droplet volumes are measured in advance. For each nozzle, up to 16 different drive waveforms are then stored in a 1k synchronous random access memory (SRAM) per nozzle for future selective use by software to provide discrete volume deviations. With different drive waveforms, each nozzle is commanded on a droplet basis for the waveform to be applied through the programming of the data to ferment the particular drive waveform.

15A illustrates this embodiment, generally designated by reference numeral 1501. In particular, processor 1503 is used to receive data that determines the intended fill volume per target area for a particular layer of material to be printed. As indicated by reference number 1505, this data may be a layout file or bitmap file that defines the droplet volume per grid point or location address. A series of piezoelectric transducers 1507, 1508, and 1509 each produce a number of factors, such as nozzle drive rupture and associated droplet volume 1511, 1512, and 1513, which depend on manufacturing variations per printhead. During the calibration operation, the use of each variable of the set of variables, such as nozzle-specific deviations and different drive waveforms, is tested for the effect on the droplet volume, taking into account the particular ink to be used, and if desired, this calibration operation. Can be made dynamically in response to changes in temperature, nozzle clogging, or another parameter, for example. This calibration is represented by a droplet measurement device 1515 that provides the measured data to the processor 1503 and is used to manage the printing plan and continue printing. In one embodiment, this measurement data takes several minutes (e.g., for thousands of printhead nozzles and dozens of possible nozzle spray waveforms), for example, less than 30 minutes for thousands of nozzles, and preferably much shorter time. Is calculated during the operation. In another embodiment, as mentioned, such measurements may be performed repeatedly, ie to update different subsets of nozzles at different points in time. Non-imaging (eg, interferometry) techniques can be used as an option as previously described, potentially resulting in dozens of droplet measurements per nozzle, covering tens to hundreds of nozzles per second. This data and any associated statistical model (and means) may be stored in memory 1517 to be used to process layout or bitmap data 1505 when received. In one implementation, the processor 1503 is part of a computer remote from the actual printing press, while in another embodiment, the processor 1503 is integral with the product manufacturing means (eg, display manufacturing system) or the printing press. do.

In order to perform the ejection of the droplets, one or more sets of timing or synchronization signals 1519 are received to be used as references, which are passed through a clock tree 1521 to the respective nozzle drivers 1523, 1524 and 1525. ) Can generate drive waveforms for each of the particular nozzles 1527, 1528, and 1529. Each nozzle driver has one or more registers 1531, 1532, and 1533 that receive multi-bit programming data and timing information from the processor 1503. Each nozzle driver and its associated registers receive one or more dedicated writable signals we _n for the purpose of programming registers 1531, 1532 and 1533, respectively. In one embodiment, each register includes a significant amount of memory for storing a plurality of designated waveforms, such as 1k SRAM, and programmable registers for selecting or otherwise controlling waveform generation from these waveforms. do. Data and timing information from the processor are shown as multi-bit information, which can be provided to each nozzle via a serial or parallel bit connection (as shown in FIG. 15B and mentioned below, one implementation). In the example, this connection is serial unlike the parallel signal representation shown in FIG. 15A).

For a particular deposition, printhead or ink, the processor selects a set of 16 drive waveforms that can be selectively applied to generate droplets for each nozzle, the number being arbitrary, e.g. in one design, 4 Waveforms may be used, and in another design 4000 waveforms may be used. These waveforms are selected to provide the desired deviation in the droplet volume output for each nozzle, so that each nozzle has at least one waveform selection that produces a near ideal droplet volume (e.g., an average droplet volume of 10.00 pL). It can provide a range of intended volume deviation for the nozzle of. In the illustrated embodiment, sixteen possible unique waveforms for each nozzle are individually predefined in advance, and although each waveform imparts its own liquidus volume characteristics, in various embodiments, sixteen drives for all nozzles The same set of waveforms is used.

)이 동기화 신호보다 수천 배 더 빠른데, 가령, 100메가헤르츠, 33메가헤르츠 등이며, 하나의 실시예에서, 복수의 서로 다른 클록 또는 또 다른 타이밍 신호(가령, 스트로브 신호)가 조합되어 사용될 수 있다. 또한 프로세서는 격자 간격(grid spacing)을 정의하는 값을 프로그래밍하며, 하나의 구현예에서, 상기 격자 간격은 이용 가능한 노즐의 전체 풀에 공통적이지만, 이는 각각의 구현예에 대해 반드시 그럴 필요는 없다. 예를 들어, 일부 경우, 모든 노즐이 "5마이크론마다" 분사하도록 하는 규칙적인 격자가 규정된다. 이 격자는 인쇄 시스템, 기판 또는 둘 모두에 고유할 수 있다. 따라서, 하나의 선택적인 실시예에서, 격자는, 기판 지오그래피와 매칭시키기 위해 기판을 효과적으로 변형시키는데 사용되는 동기 주파수 또는 노즐 분사 패턴으로 특정 인쇄기를 위해 형성될 수 있다. 또 다른 고려되는 실시예에서, 하나의 메모리가 모든 노즐에 걸쳐 공유되어, 프로세서가 모든 노즐에 걸쳐 공유되는 복수의(가령, 16) 서로 다른 격자 간격을 사전-저장할 수 있게 함으로써, 상기 프로세서는 (필요에 따라) (가령, 불규칙한 격자를 정의하기 위해) 모든 노즐에게 판독될 새 격자 간격을 선택할 수 있다. 예를 들어, (가령, 비-컬러 특정 층을 증착하기 위해) 노즐이 OLED의 모든 컬러 성분 우물에 대해 분사할 하나의 구현예에서, 프로세서에 의해 셋 이상의 서로 다른 격자 간격이 라운드 로빈(round robin) 방식으로 연속적으로 적용될 수 있다. 명백하게도, 많은 설계적 대안이 가능하다. 프로세서(1503)는 동작 동안 각각의 노즐의 레지스터를 동적으로 재프로그램할 수 있다, 즉, 이의 레지스터에서 임의의 프로그램된 파형 펄스 세트를 런칭(launch)하기 위한 트리거로서 동기화 펄스가 인가되고, 다음 동기화 펄스 전에 새 데이터가 비동기식으로 수신된 경우, 새 데이터가 다음 동기화 펄스와 함께 적용될 것이다. 또한 프로세서(1503)는 동기화 펄스 생성(1536)에 대한 파라미터를 설정하는 것에 추가로 스캐닝(1535)의 개시 및 속도를 제어한다. 덧붙여, 프로세서가 앞서 기재된 다양한 목적으로 인쇄헤드(1537)의 회전을 제어한다. 이러한 방식으로, 각각의 노즐은 임의의 때에(즉, 임의의 "다음" 동기화 펄스에 의해) 각각의 노즐에 대해 16개의 서로 다른 파형 중 임의의 하나를 이용해 동시에 분사할 수 있고, 단일 스캔 동안 분사와 분사 사이에서, 선택된 분사 파형이 동적으로 16개의 서로 다른 파형에 의해 스위칭될 수 있다.During printing, in order to control the deposition of each droplet, data selecting one of the designated waveforms is programmed into the respective register 1531, 1532 or 1533 of each nozzle on a nozzle basis. For example, given a target volume of 10.00 pL, the nozzle driver 1523 can be configured to set one of the 16 waveforms corresponding to one of the 16 different droplet volumes by writing data to the register 1531. Can be. The volume produced by each nozzle is measured by the droplet measurement device 1415, wherein the nozzle-by-nozzle (and waveform-specific) droplet volume and associated distribution are determined by the processor 1503 to help produce the desired target fill amount. Are registered and stored in memory. The processor determines whether the particular nozzle driver 1523 outputs the waveform selected by the processor among the 16 waveforms or not by programming the register 1531. In addition, for example, to align each nozzle to a grid across which the printhead traverses, to correct for errors including speed or trajectory, and for other purposes, the processor may apply nozzles to a jet of nozzles for a particular scan line. The registers can be programmed to have a delay or offset per unit, which is caused by a counter skewing a particular nozzle (or injection waveform) by a programmable number of timing pulses for each scan. To provide an example, if the results of droplet measurements indicate that one particular droplet tends to have a lower speed than expected, the corresponding nozzle waveform is triggered earlier (eg, an active signal used for piezoelectric operation). By reducing the dead time before the level, in advance), on the contrary, if the result of the droplet measurement indicates that one particular droplet has a relatively high velocity, the waveform may be triggered later. Other examples are apparently possible, for example, in some embodiments, slow droplet velocity may be countered by increasing drive strength (ie, the signal level and associated voltage used to drive the piezo actuator of a given nozzle). have. In one embodiment, a synchronization signal distributed across all nozzles occurs at a defined time interval (eg, 1 microsecond) for synchronization, and in another embodiment, the synchronization signal is generated by press motion and substrate geometries. geography), for example, to spray per micron of incremental relative motion between the printhead and the substrate. High speed clock

) Is several thousand times faster than a synchronization signal, such as 100 MHz, 33 MHz, etc. In one embodiment, a plurality of different clocks or another timing signal (eg, strobe signal) may be used in combination. . The processor also programs a value that defines grid spacing, and in one implementation, the grid spacing is common to the entire pool of available nozzles, but this is not necessarily the case for each implementation. For example, in some cases, a regular grating is defined that causes all nozzles to spray “every 5 microns”. This grating may be unique to the printing system, the substrate, or both. Thus, in one alternative embodiment, the grating may be formed for a particular printer with a synchronous frequency or nozzle spray pattern used to effectively deform the substrate to match the substrate geometry. In another contemplated embodiment, one memory is shared across all nozzles, allowing the processor to pre-store a plurality of (eg, 16) different grid spacings that are shared across all nozzles. As needed, you can select a new grating spacing to be read for all nozzles (eg to define an irregular grating). For example, in one embodiment in which a nozzle will spray for all color component wells of an OLED (eg, to deposit a non-color specific layer), three or more different grating spacings may be round robin by the processor. Can be applied continuously. Clearly, many design alternatives are possible. The processor 1503 may dynamically reprogram the register of each nozzle during operation, that is, a synchronization pulse is applied as a trigger to launch any set of programmed waveform pulses in its register, and then the next synchronization. If new data is received asynchronously before the pulse, the new data will be applied with the next synchronization pulse. The processor 1503 also controls the initiation and speed of scanning 1535 in addition to setting parameters for synchronization pulse generation 1536. In addition, the processor controls the rotation of the printhead 1537 for the various purposes described above. In this way, each nozzle can spray at the same time using any one of 16 different waveforms for each nozzle at any time (i.e., by any " next " synchronization pulse), and spray during a single scan. Between and injection, the selected injection waveform can be dynamically switched by 16 different waveforms.

)의 입력을 수신한다. 레지스터 파일(1543)이 초기 오프셋, 격자 결정 값(grid definition value), 및 구동 파형 ID를 각각 전달하는 적어도 3개의 레지스터에 대한 데이터를 제공한다. 초기 오프셋은, 앞서 언급된 바와 같이, 각각 노즐을 격자의 시작 부분과 정렬되도록 조절하는 프로그램 가능한 값이다. 예를 들어, 구현 변수, 가령, 복수의 인쇄헤드, 복수의 노즐 행, 서로 다른 인쇄헤드 회전, 노즐 분사 속력 및 패턴 및 그 밖의 다른 요인들이 주어지면, 딜레이 및 그 밖의 다른 요인을 고려하기 위해 초기 오프셋이 각각의 노즐의 액적 패턴을 격자의 시작 부분과 정렬하도록 사용될 수 있다. 오프셋은 가령, 기판 지오그래피에 대해 격자 또는 해프톤 패턴을 회전하기 위해, 또는 기판 오정렬을 교정하기 위해, 복수의 노즐에 걸쳐 상이하게 적용될 수 있다. 마찬가지로, 언급된 바와 같이, 오프셋은 이탈된 속도 또는 다른 효과를 교정하는데 사용될 수도 있다. 격자 결정 값은 프로그래밍된 파형이 트리거되기 전에 "카운팅되는" 동기화 펄스의 개수를 나타내는 숫자이며, 평면 패널 디스플레이(가령, OLED 패널)를 인쇄하는 구현예의 경우, 인쇄될 타깃 영역은 규칙적인(일정한 간격) 또는 불규칙적인(복수의 간격) 격자에 대응하는 서로 다른 인쇄헤드 노즐에 대한 하나 이상의 규칙적 간격을 가진다. 앞서 언급된 바와 같이, 하나의 구현예에서, 프로세서는 자신의 고유의 16-엔트리 SRAM을 유지하여, 모든 노즐에 대해 레지스터 회로로 필요에 따라 판독될 수 있는 최대 16개의 서로 다른 격자 간격을 결정할 수 있다. 따라서 격자 간격 값이 2로 설정된 경우(2마이크론마다), 각각의 노즐은 이 간격에서 분사될 것이다. 구동 파형 ID는 각각의 노즐에 대한 사전-저장된 구동 파형들 중 하나의 선택을 나타내며, 하나의 실시예에 따라, 많은 방식으로 프로그래밍 및 저장될 수 있다. 하나의 실시예에서, 구동 파형 ID는 4비트 선택 값이고, 각각의 노즐은 16x16x4B 엔트리로서 저장되는 최대 16개의 지정 노즐 구동 파형을 저장하기 위해 각자의 전용 1k-바이트 SRAM을 가진다. 간단히 말하면, 각각의 파형에 대한 16개의 엔트리 각각이 프로그램 가능한 신호 레벨을 나타내는 4 바이트를 포함하며, 이들 4 바이트는 2-바이트 분해능 전압 레벨 및 2-바이트 프로그램 가능한 지속시간을 나타내며, 고속 클록의 펄스의 개수를 카운팅하도록 사용된다. 따라서 각각의 프로그램 가능 파형은 각각의 프로그램 가능 전압 및 지속시간(가령, 33 메가헤르츠 클록의 1-255 펄스와 동일한 지속시간)의 최대 16개의 이산 펄스까지의 (0 내지 1) 이산 펄스로 구성될 수 있다.FIG. 15B shows additional details of the circuit 1541 used in this embodiment to generate an output nozzle drive waveform for each nozzle, in which the output waveform is represented by “ nzzl-drv.wvfm ”. More specifically, the circuit 1541 includes a synchronization signal, a single bit line with continuous data (“data”), a dedicated writable signal (we), and a high speed clock (

Receives the input of). Register file 1543 provides data for at least three registers, each carrying an initial offset, a grid definition value, and a drive waveform ID. The initial offset, as mentioned above, is a programmable value that adjusts each nozzle to align with the beginning of the grating. For example, given implementation variables, such as a plurality of printheads, a plurality of nozzle rows, different printhead rotations, nozzle ejection speeds and patterns, and other factors, the initial to account for delays and other factors. An offset can be used to align the droplet pattern of each nozzle with the beginning of the grating. The offset may be applied differently across the plurality of nozzles, for example, to rotate the grating or halftone pattern relative to the substrate geometry, or to correct substrate misalignment. Likewise, as mentioned, offsets may be used to correct deviated speed or other effects. The lattice decision value is a number that indicates the number of sync pulses that are "counted" before the programmed waveform is triggered, and for embodiments that print flat panel displays (e.g., OLED panels), the target area to be printed is regular (constant intervals). ) Or one or more regular intervals for different printhead nozzles corresponding to irregular (multiple intervals) grids. As mentioned above, in one implementation, the processor maintains its own 16-entry SRAM to determine up to 16 different grating spacings that can be read as needed into the register circuit for every nozzle. have. Thus, if the lattice spacing value is set to 2 (every 2 microns), each nozzle will be sprayed at this interval. The drive waveform ID represents a selection of one of the pre-stored drive waveforms for each nozzle and can be programmed and stored in many ways, according to one embodiment. In one embodiment, the drive waveform ID is a 4-bit selection value, and each nozzle has its own dedicated 1k-byte SRAM to store up to 16 designated nozzle drive waveforms stored as 16x16x4B entries. In short, each of the 16 entries for each waveform contains four bytes representing a programmable signal level, these four bytes representing a two-byte resolution voltage level and a two-byte programmable duration, and a pulse of a high speed clock. It is used to count the number of. Thus each programmable waveform may consist of (0 to 1) discrete pulses of up to 16 discrete pulses of each programmable voltage and duration (e.g., duration equal to 1-255 pulses of a 33 MHz clock). Can be.

)에 따라 타이밍되는 고속 디지털-아날로그 변환기(1548), 카운터(1549), 고전압 증폭기(1550)를 기초로 한다. 제 2 카운터(1546)로부터의 트리거가 수신될 때, 파형 생성기 회로가 구동 파형 ID 값에 의해 나타나는 숫자 쌍(신호 레벨 및 지속시간)을 불러오며 신호 레벨 값에 따라 특정 아날로그 출력 전압을 생성하고, 이때, 카운터(1549)는 카운터에 따라 지속시간 동안 DAC 출력을 유지하기 위해 기능한다. 그 후 적절한 출력 전압 레벨이 고전압 증폭기(1550)로 적용되고 노즐-구동 파형으로서 출력된다. 그 후 다음 숫자 쌍이 레지스터(1543)로부터 불러와져, 다음 신호 레벨 값/지속시간 등을 결정할 수 있다.Reference numerals 1545, 1546, and 1547 indicate one embodiment of a circuit that shows how a waveform specified for a given nozzle can be generated. The first counter 1545 receives a synchronization pulse to initiate a countdown of the initial offset triggered by the beginning of a new line scan, and the first counter 1545 counts down the increment in microns and reaches zero. When triggered, a trigger signal is output from the first counter 1545 to the second counter 1546, which triggers a spraying process for each nozzle for each scan line substantially. Second counter 1546 then implements the programmable grid spacing in increments of microns. The first counter 1545 is reset in combination with the new scan line, while the second counter 1546 is reset using the next edge of the high speed clock after its output trigger. The second counter 1546 activates a waveform circuit generator 1547 that, when triggered, produces a selected drive waveform shape for a particular nozzle. As indicated by dashed boxes 1548-1550 shown below the generator circuit, the circuit is a fast clock (

Is based on a high speed digital-to-analog converter 1548, a counter 1549, and a high voltage amplifier 1550. When a trigger from the second counter 1546 is received, the waveform generator circuit recalls a pair of numbers (signal level and duration) represented by the drive waveform ID value and generates a specific analog output voltage in accordance with the signal level value, At this time, the counter 1549 functions to maintain the DAC output for a duration according to the counter. The appropriate output voltage level is then applied to the high voltage amplifier 1550 and output as a nozzle-drive waveform. The next pair of numbers can then be retrieved from register 1543 to determine the next signal level value / duration and the like.

The circuit shown provides an effective means of determining any desired waveform in accordance with the data provided by the processor 1503. The first " 0 " signal determining the voltage level associated with the interval and / or any particular signal level (e.g., an offset associated with synchronization), as needed to mitigate a nozzle having a velocity or flight angle that is compliant with or disengaged from the lattice geometry. Level) can be adjusted. As mentioned above, in one embodiment, the processor determines in advance a set of waveforms (eg, 16 possible waveforms, per nozzle) and then determines each of these selected waveforms for the driver circuit of each nozzle. By writing a definition to the SRAM and then writing a 4-bit drive waveform ID to each nozzle register, a " firing-time " determination of the programmable waveform is initiated.

15c provides a flow chart 1551 describing how to use different waveforms and different configuration options per nozzle. As indicated by 1553, a system (eg, one or more processors operating according to instructions from appropriate software) selects a set of designated nozzle drive waveforms. For each waveform and for each nozzle 1555, the droplet volume is specifically measured using a laser measuring device or a CCD camera and a statistical model is established. These volumes are stored in memory, such as memory 1557, accessible by the processor. Again, the measured parameters may change depending on the choice of ink and many other factors, so calibration is performed in accordance with these factors and the planned deposition activity. For example, in one embodiment 1561, a calibration may be performed at a factory that manufactures a printhead or a press, and this data may be pre-programmed or downloaded to a device on sale (eg, a press). Alternatively, for a press having an optional droplet measurement device or system, these volume measurements may be performed when first used, such as upon initial device setup, 1562. In another embodiment, each power cycle (e.g. each time the printer is "on", or whenever it is awakened from a low power state or moved to a state ready to print in other ways, Measurement is performed by 1563). As mentioned above, in embodiments where the ejected droplet volume is affected by temperature or other dynamic factors, when an error is detected intermittently or periodically, for example after a defined time period has expired, When the state of each new substrate operation (eg, during substrate loading and / or loading), calibration may be performed on a daily or other basis (1564). Other calibration techniques and schedules may also be used (1565).

Optionally, as indicated by process separation line 1566, the calibration technique may be performed in an offline process or during a calibration mode. As mentioned above, in one embodiment, this process is completed within less than 30 minutes for thousands of print nozzles and for one or more associated nozzle spray waveforms. During the on-line operation (or during print mode) appearing below this process separation line 1566, the measured droplet volume is used to select a set of droplets per target area based on the particular measured droplet volume, so that each set is The droplet volume for the can be summed up to a certain cumulative volume within the specified tolerance range (1567). The volume per area may be selected based on layout file, bitmap data, or some other representation, as indicated by reference number 1568. Based on these droplet volumes and the authorized combination of droplet volumes for each target region, as indicated by reference numeral 1569, a particular combination of droplets for each target region to be actually used for the deposition process (ie, A spray pattern and / or a scan path is selected that represents one of the allowed sets of combinations). As part of this selection or planning process 1569, an optional optimization function 1570 may optionally be employed to determine, for example, the number of scans or passes of the average number of droplets per target area and the number of rows (or columns) of the target area. Is rotated by 90 degrees to be less than the product (e.g., all nozzles in a row can be used in each scan for each affected target area, depositing droplets in multiple passes for each row of the target area, When advancing one row at a time, it may be reduced (to be smaller than would be required for one row of nozzles). For each scan, the printhead can be moved and waveform data per nozzle can be programmed into the nozzle to effect the droplet deposition command in accordance with the bitmap or layout file, these functions being indicated by reference numeral 1571 in FIG. 15C. , 1573 and 1575). After each scan, the process is repeated 1577 for the next scan. Optionally, these techniques and implementations thereof may be implemented in the press control file 1579 and subsequently developed or used to control the ejection of ink at a particular time.

Again, several different implementations have been described above that are optional for each other. First, in one embodiment, the drive waveform remains unchanged for each nozzle. Droplet volume combinations are created as needed by using variable geometric steps representing printhead / substrate offsets for overwriting different target area rows on different nozzles. By using the measured droplet volume averages per nozzle, there is a high confidence that any droplet deviation can be accommodated within the desired tolerances, and this process allows a combination of specific droplet volumes to achieve a very specific fill volume per target area (eg, 0.01 pL resolution). To get). With each pass, this process can be planned so that a plurality of nozzles are used to deposit ink into different target area rows. In one embodiment, the print resolution is optimized to produce the lowest possible number of scans and the minimum possible print time. Second, in another embodiment, different drive waveforms may be used for each nozzle using specifically measured droplet volumes. The printing process controls these waveforms so that specific droplet volumes accumulate in specific combinations. Once again, using the measured droplet volume per nozzle, this process allows a combination of specific droplet volume averages to achieve a very specific fill volume per target area (eg, 0.01 pL resolution). This process can be planned so that a plurality of nozzles are used to deposit ink in different target area rows by each pass. In all of these embodiments, a single nozzle row may be used or multiple nozzle rows arranged as one or more printheads of the printhead assembly, for example, in one contemplated embodiment, 30 printheads may be used. Each printhead has a single nozzle row, and each row has 256 nozzles. The printheads can be further organized into a variety of different groups such as, for example, these printheads can be organized into printhead assemblies each having five printheads all mechanically mounted together, and these final six assemblies can be printed. Can be mounted individually into the system. In another embodiment, a cumulative printhead assembly is used having a plurality of nozzle rows that can be further offset in position relative to each other. This embodiment is similar to the first embodiment mentioned above in that different droplet volumes can be combined using various effective position offsets or geometric steps. In other words, using the measured droplet volume per nozzle, this process allows a combination of specific droplet volume averages to achieve a very specific fill volume per target area (eg, resolution of 0.05 pL or even 0.01 pL). This does not necessarily mean that there is no statistical uncertainty in the measurement, such as measurement error, and in one embodiment, this error is small and taken into account when planning the target area charge. For example, if the droplet volume measurement error is ± a%, the fill volume deviation across the target area may be planned to be within ± (b-an ^-1/2 )% tolerance of the target fill volume, where ± (b) % Represents the specification tolerance range and n ^1/2 represents the square root of the average number of droplets per target area or well. Unless stated otherwise, for example, as described above with respect to FIGS. 8A-8B, when the expected measurement error is taken into account, a range less than the specification tolerance may be planned such that the final cumulative filling volume for the target area is within the specification tolerance range. Can be. It is apparent that the techniques described herein may be optionally combined with other statistical processes.

Optionally, droplet deposition can be planned such that a plurality of nozzles are used to deposit ink in different rows of the target area by each pass, optionally with the smallest number of scans possible and the smallest possible prints possible. Is optimized to generate time. As mentioned above, each of the other techniques and any combination of these techniques can also be used. For example, in one specifically contemplated scenario, variable geometric steps may be used with drive waveform deviations per nozzle and volume measurements per nozzle and per drive waveform to obtain a very specific volume combination planned per target area. For example, in another particularly contemplated scenario, a fixed geometric step may be used with drive waveform deviation per nozzle and volume measurement per drive waveform per nozzle to obtain a very specific volume combination planned per target area.

By maximizing the number of nozzles that can be used simultaneously during each scan and planning the droplet volume combination to meet specifications, these embodiments promise a high quality display by also reducing the printing time, and these embodiments reduce the cost of ultra low unit printing. And therefore lower the price point of the end consumer.

15D provides a flow chart related to nozzle qualification. In one embodiment, droplet measurements are performed so that, for each waveform applied to each nozzle and any given nozzle, a statistical model (eg, distribution) for any and / or each droplet volume, velocity, and trajectory And average). Thus, for example, if there are two waveform selections for each of dozens of nozzles, there are 24 waveform-nozzle combinations or pairings, and in one embodiment, the measurement for each parameter (eg volume) is robust statistically. Taken for each nozzle or waveform-nozzle pairing sufficient to develop the model. Despite the scheme, it is conceptually possible that a given nozzle or nozzle-waveform pairing can produce an especially wide distribution or a sufficiently deviated mean that must be specially processed. This particular process applied to one embodiment is conceptually represented by FIG. 15D.

More specifically, the general method is indicated using reference numeral 1581. The data generated by the droplet measurement device is stored by the memory 1585 for later use. While the method 1581 is utilized, this data is recalled from memory, and the data for each nozzle or nozzle-waveform pairing is extracted and processed 1583 separately. In one embodiment, as mentioned, a normal random distribution is applied to each variable to be qualified, as described, by means of averages, standard deviations, and the number of droplets measured (n) or using equivalent measures. Is formed. Note again that other types of distribution may be used (eg Student's T, Poisson, etc.). The measured parameters are compared to one or more ranges 1587 to determine if the relevant droplet can actually be used. In one embodiment, at least one range is applied to disqualify the droplet from use (eg, if the droplet has a volume large or small enough for the desired target, the nozzle or nozzle-waveform pairing is excluded from short term use). ). To provide an example, if a 10.00 pL droplet is desired, for example a nozzle EH associated with a droplet average 1.5% away from this target (eg, <9.85 pL or> 10.15 pL), the nozzle-waveform may be excluded from use. Range, standard deviation, variance, or another spread measure may also be used instead. If a droplet statistical model is desired with a narrow distribution (eg 3σ <1.005% of the mean), droplets with measurements that do not meet these criteria can be excluded. It is also possible to use a refined / complex set of criteria which takes into account a plurality of elements. For example, the deviation mean combined with a very narrow spread may be good, for example, if the spread (eg 3σ) (eg deviation) mean (μ) away from what is measured is within 1.005%, then the associated droplet may be used. Can be. For example, if you want to use droplets with a volume of 3σ within 10.00pL ± 0.1 pL, nozzle-waveform pairing that produces a 9.96pL average with ± 0.8pL 3σ may be excluded, but with ± 0.3pL 3σ Nozzle-waveform pairing to produce a 9.93 pL average may be acceptable. It is clear that there can be many countermeasures according to any desired rejection / exit criteria 1589. It should be borne in mind that this type of treatment can be applied for flight angles and speeds per drop, ie the flight angles and speeds per nozzle-wave pairing will represent a statistical distribution, which is a statistical and measurement derived from a droplet measurement device. Depending on the model, it is expected that some droplets may be excluded. For example, droplets with an average velocity or flight trajectory that is outside 5% of the variance in the average outside of normal or specific targets may be virtually excluded from use. Various ranges and / or evaluation criteria may be applied to each droplet parameter provided and measured by the reservoir 1585.

Depending on the rejection / exit criteria 1589, the droplets (and droplet-waveform combinations) may be processed and / or processed in a variety of ways. For example, certain droplets that do not meet the desired normal are rejected 1591 as previously mentioned. Alternatively, it is possible to selectively perform additional measurements for the next measurement iteration of a particular nozzle-waveform pairing, for example, if the statistical distribution is too wide, to improve the tightness of the statistical distribution through additional measurements, Further measurements of nozzle-waveform pairing can be made explicitly (eg variance and standard deviation depend on the number of measured data points). For reference numeral 1593, the nozzle drive waveform can be adjusted, for example, to use a higher or lower voltage level (e.g., to provide a larger or smaller speed or a more constant flight angle), or to specify a specified norm. The waveform can be reshaped to produce a regulated nozzle-waveform pairing that satisfies. For reference numeral 1594, the timing of the waveform may also be adjusted (eg, to compensate for a missed mean velocity associated with a particular nozzle-waveform pairing). As an example (previously suggested), slow droplets may be injected earlier than other nozzles, and faster droplets may be injected later in time to compensate for faster flight times. Many alternatives are possible. Finally, in reference numeral 1595, any adjusted parameter (eg, injection time, waveform voltage level or shape) may be stored, and optionally, if desired, the adjusted parameter may be applied to remeasure one or more related droplets. Can be. After each nozzle-waveform pairing (modified or not) is qualified (passed or rejected), the method proceeds to the next nozzle-waveform pairing, for reference numeral 1597.

As will be appreciated, the nozzle drive structure just described provides flexibility in printing droplets of various sizes. The use of accurate fill volume, droplet volume, droplet velocity and droplet trajectory per target area allows for varying the filling volume and planning for nozzle / waveform and / or droplet usage according to defined criteria (within specifications). Enable the use of. This provides further quality improvement over the conventional method.

16-18B will now be used to provide details that are two contemplated droplet measurement devices (or systems), namely traces, respectively predicted by shadow plots and interference measurements. 16-17 will be used to represent one embodiment of a printing press with a droplet measurement system, while FIGS. 18A and 18B will be used to discuss shadow plots and interference measurements, respectively.

As noted previously, the present disclosure discloses various embodiments of an industrial inkjet thin film printing system that includes a drop measurement device integrated into a printing system. Various embodiments of the inkjet thin film printing system of the present disclosure may use imaging techniques such as shadow painting or non-imaging techniques (such as based on interference measurements), such as phase Doppler analysis (PDA), which may be used to generate a plurality of inkjet printheads. It can provide significant advantages for quick measurement of nozzles, and various embodiments of a printhead assembly used in a thin film inkjet printing system according to the present disclosure can have multiple printheads. Such a quick measurement can be performed in place at any time during the printing process and can provide data that can include volume, velocity and trajectory for each drop from each nozzle of each printhead. . Collective data obtained from drop measurement devices integrated into an inkjet thin film printing system can be used to provide uniformity of ink volume delivered to hundreds of pixels on an OLED panel display.

When depositing a film in the manufacture of an OLED panel, it is often desirable to deposit a film material of uniform thickness across the panel, because the thickness of the deposited material often affects panel performance, resulting in good display uniformity. This is because it is an important property of OLED panels. When using an inkjet printing method to deposit a film, a drop of ink is ejected from the printing apparatus onto the panel substrate, and the thickness of the film deposited in each area of the panel is generally determined by the amount of ink dispensed in that area of the panel. Volume, which is further related to the volume and location of the drop onto the panel surface. Therefore, it is often desirable to evenly distribute the volume of ink in relation to both the volume and location of the drop dispensed across the OLED panel display.

As noted previously, inkjet printing systems typically have at least one printhead with a plurality of inkjet nozzles, each nozzle distributing a drop of ink onto the panel surface. Typically, there is a variation over a plurality of nozzles of the print head with respect to volume, trajectory and speed of the dispensed drop. These variations are not limited to variations in nozzle operating conditions, variations in the original nozzle actuator behavior including the age of the piezoelectric nozzle driver, variations in ink, and variations in the original nozzle size and shape. Can occur from a source of. The effect of this variation can lead to non-uniformity in volume loading across the panel. For example, deviations in the drop volume can lead directly to deviations in the deposited volume, while deviations in drop velocity and trajectory cause deviations in the position of the drop on the OLED panel surface, thereby causing deposition of the ink. This can indirectly lead to deviations in volume. In theory, these deviations can be avoided by using only one nozzle when printing, but printing using one nozzle is too slow for practical use in manufacturing applications. In terms of this variation in ink drop dispensed from different nozzles and the practical necessity of using multiple nozzles to achieve reasonable processing speed when using inkjet printing for manufacturing applications, this variation in drop between nozzles It would be desirable to have a method and apparatus associated therewith for providing a uniform distribution of ink across an area of an OLED panel.

The measuring device integrated into the thin film inkjet printing system according to the present disclosure allows the actual measurement of volume, velocity and trajectory for each nozzle of the inkjet printhead for any time or at intermittent times for the execution of a printing process. Can be used to provide Such measurements can provide mitigation of drop variation between nozzles in order to achieve a more uniform deposition of film material using an inkjet method. In some embodiments, these measurements can be used to tune printhead performance by adjusting drive waveforms for each of the individual nozzles to directly reduce drop variation between nozzles. In some embodiments, this measurement can be used as an input to a print pattern optimization system that can reduce the internozzle variation by adjusting nozzle selection for drop deposition to average the internozzle drop variation in the deposited film. . Various embodiments of the measuring device integrated into the thin film inkjet printing system of the present disclosure may use various imaging techniques such as shadow painting or non-imaging techniques such as PDAs. In particular, PDAs can provide the significant benefit of quickly analyzing a plurality of nozzles of an inkjet printhead, particularly useful for systems with many nozzles and / or printheads.

In this regard, an inkjet thin film printing system according to various embodiments of the present disclosure may be comprised of several devices and devices, which enables reliable placement of ink drops onto specific locations on a substrate. These devices and devices are, by way of non-limiting example, a printhead assembly, an ink delivery system, a motion system, a substrate support device such as a float table or a chuck, a substrate loading and unloading system, a printhead holding system and a printhead measuring device. It includes. In addition, the inkjet thin film printing system may be mounted on a stable support assembly, which may include, for example, a granite or metal base. The printhead assembly may be comprised of at least one inkjet printhead, wherein at least one orifice may eject a drop of ink at a controlled rate, the ejected drop being dependent upon their volume, velocity and trajectory. It is further characterized by.

Since printing requires relative motion between the printhead assembly and the substrate, the printing system may include a motion system, such as a gantry or split axis XYZ system. The printhead assembly may move over a stationary substrate (support style), or both the printhead and the substrate may move, for example in a split axis configuration. In another embodiment, the print station may be stationary and the substrate may move in the X and Y axes relative to the printhead and move while providing Z-axis motion to the substrate or printhead. As the printhead moves relative to the substrate, a drop of ink is ejected at the correct time to be deposited at the desired location on the substrate. The substrate is inserted into the printing press and removed using a substrate loading and unloading system. Depending on the press configuration, this can be achieved by a robot with a mechanical conveyor, substrate floatation table or end effector. The printhead measurement and retention system is designed for ejecting ink into waste basins, printhead maintenance procedures such as wiping inkjet nozzle surfaces, as well as drop volume identification, drop volume, velocity and trajectory measurements. It can consist of several subsystems for measurements such as priming. Considering various configurations that may include an inkjet thin film printing system, various embodiments of an inkjet thin film printing system according to various embodiments of the present disclosure may have various footprints and form factors.

As a non-limiting example, FIG. 16 shows an inkjet thin film printing system according to various embodiments, which may be used to print substrates such as, but not limited to, OLED panels. In FIG. 16, the inkjet thin film printing system 1600 uses a split-axis motion system. Inkjet thin film printing system 1600 may be mounted on a printing system support assembly 1610, which may include a fan 1612 carried by a support frame 1614. Base 1616 is mounted on a pan, while base may optionally be constructed of granite or metal. The inkjet thin film printing system may include a motion system 1620, as indicated by a split axis motion system.

Motion system 1620 appears to include a bridge 1622 that supports X-axis carriage 1624 and eventually mounts to Z-axis mounting plate 1626. Finally, the Z-axis mount plate is used to support the printhead mounting and clamping assembly 1628 and to mount the interchangeable printhead assembly 1640. For the split-axis motion system 1620, the Y-axis track 1623 can be mounted over the base 1616 to support the Y-axis carriage 1625, eventually carrying the substrate support assembly 1630. And these various configurations provide Y-axis movement of the substrate mounted on the substrate support assembly 1630. As shown in FIG. 16, in various embodiments of the thin film printing system, the substrate support assembly 1630 may be a chuck. The substrate support assembly may be provided with a floating table, as described in detail in US Pat. No. 8,383,202, which is incorporated herein by reference. Inkjet thin film printing system 1600 may use a system assembly that supports one or more modular inkjet printhead assemblies, such as the various printhead assemblies shown mounted on a tool carousel 1645. Providing selective exchange of various printhead assemblies can provide the end user with flexibility for efficient sequential printing of various inks of various fabrication on the substrate, such as during printing of OLED panel substrates. . This is not required for all embodiments, i.e., other embodiments may feature one printhead assembly that does not change between different printing processes. For example, one contemplated embodiment features an assembly line of a plurality of printing presses, each of which performs its own printing process (eg, using each ink), and the techniques described herein It can be applied to each such printing press.

The printhead assembly may include a fluid system having an ink reservoir in fluid communication with at least one inkjet printhead, for example, to deliver an OLED film-forming material onto a substrate. In this regard, as shown in FIG. 16, printhead assembly 1640 may include at least one printhead 1644. In various embodiments, the printhead assembly may optionally include fluid and electrical connections to each printhead. Each printhead may, in turn, have a plurality of nozzles or orifices capable of ejecting ink droplets at a controlled rate, with measurable droplet volume, velocity and trajectory. Various embodiments of printhead assembly 1640 may have about 1 to about 30 printheads per printhead assembly. Printhead 1644 may have about 16 to about 2048 nozzles, each of which may eject a droplet volume of about 0.10 pL to about 200.00 pL.

Measuring the performance of each nozzle of a given printhead may include measuring drop volume, velocity, and trajectory, as well as checking for nozzle injection. As mentioned previously, having such measurement data is to tune the head before printing to provide more uniform performance for each nozzle, but to provide a printing algorithm that can compensate for differences during printing. Risk measurement data may be used, or a combination of these approaches may be provided. Obviously, having a reliable and up-to-date data set of measurement data can provide a variety of approaches that can use the measurement data to compensate for droplet volume variations between nozzles (either from the same nozzle or by using various drive waveforms or Allow for a planned printing process that combines various volumes of droplets (from their respective nozzles). As noted previously, measurement data is preferably collected to express a population of measurements representing a distribution for each nozzle, and the prediction of the average droplet volume, trajectory, and velocity is based on the expected deviation of these droplet parameters. It is developed with well-formed comprehension and used in print planning.

In this regard, the illustrated inkjet thin film printing system may include a droplet measurement device or system 1650, which may be mounted on a support 1655. It is contemplated that various embodiments of droplet measurement system 1650 may be based on imaging or non-imaging techniques, such as, for example, shadow-based or interferometric-based methods, as mentioned. Embodiments using non-imaging PDA techniques include a significant analysis that rapidly analyzes about 16 to about 2048 nozzles of each printhead, such as printhead 1644 (eg, approximately 50 times faster than typical imaging techniques). This can provide an advantage. The printhead assembly may include, for example, 30 printheads (ie, including a printing system using more than 10,000 nozzles), which is fast, in place, and all nozzles (and all alternating actuations in connection with embodiments). Allow dynamic measurements in the press and recalibrate the droplets every 2-24 hours, or more often. Moreover, various embodiments of systems and methods in accordance with the present disclosure can use a PD® measurement device that is integrated into a gas enclosure assembly and system that can accommodate a printing apparatus. Such systems and methods using a PDA measurement device integrated into a gas enclosure assembly and system containing a printing apparatus can provide fast measurement in place of a plurality of nozzles within a printhead. This is particularly useful for ensuring a uniform deposition volume over a large substrate, for example with one or more OLED devices, and reducing any Mura effect.

Reference numeral 1617 is used to mark the area of the inkjet printing apparatus associated with the droplet measurement system 1650. This area is shown in enlarged detail in FIG.

As shown in FIG. 17, the printhead assembly 1740 can be secured by the printhead mounting and clamping assembly 1728 during printing, which is itself by the Z-axis mount 1726 of the motion system. It is carried once again. In this regard, a motion system is used to position the printhead assembly 1740 for measurement, such as near the droplet measurement system 1750 in a service area or service station. As noted previously, the submerger measurement system 1750 may be designed to selectively disconnect from the connection while the printhead assembly 1740 is in this position. Using a large printhead assembly (eg, thousands of nozzles), such a structure is subjected to a droplet measurement system while the printhead assembly 1740 is "stopped", while other tests or calibration equipment or processes ( Not shown). For example, printhead nozzles can be removed, cleaned or managed, and the use of simultaneous processes can be applied to minimize downtime of the overall inkjet printing system, which maximizes manufacturing productivity. As noted previously (and as described below with respect to FIG. 19), as the substrate is transferred, dried, cured, loaded or unloaded, droplet measurement (and other services) can be performed and also printed. For unavoidable tasks associated with manufacturing operations, stack droplet measurements to minimize any system downtime. Each nozzle of the printhead 1742 of the printhead assembly 1740 may be adjusted to the measurement area 1756 for measurement of droplets ejected from each nozzle using the droplet measurement system 1750. In this embodiment, each printhead 1742 may be moved relative to another printhead for analysis, but once again, this is not required for all embodiments. For example, with an advanced droplet measurement system at each printhead position and at each nozzle position within a given printhead, it is possible to statistically mount each printhead during measurement, as previously noted, the printhead assembly Allows for simultaneous processing or "stacking" of a plurality of service operations. For example, it is also possible to use a plurality of droplet measurement systems to independently measure various nozzles of various, spatially separated printheads.

For the sake of explanation, it should be assumed that the droplet measurement system is a PDA device (ie an interferometry-based device) with a light source such as laser burnout and light transmitting optics, a beam splitter and a transmission lens. In addition, such a PDA device may have a receiving optical including a receiving lens and a plurality of photodetectors. For example, the first optical side 1722 of the droplet measurement system 1750 can obtain one or more light rays for measurement and can focus light on the measurement area 1756, as indicated by the hatch line. On the other hand, the second optical side 1754 may pass measurement light that has been dispersed from droplets within the measurement area 1756 to receive the optics and one or more light detectors.

Droplet measurement system 1750 may be directly or remotely bound to a computer or computing device (not shown). Such computing devices provide signals indicative of the droplet volume, velocity, and trajectory measured for each droplet produced by the nozzle (or nozzle-waveform combination) from each printhead 1742 of the printhead assembly 1740. Can be configured to receive. In other words, multiple measurements of many droplets from each nozzle / nozzle-waveform pairing is preferably performed to develop a statistical population representing various produced droplets.

As noted previously in connection with FIGS. 11 and 12, various embodiments of the printing system may be housed in a gas enclosure that is inert and provides a low-particle environment, with droplet measurement preferably occurring in such an environment. . In one embodiment, the droplet measurement is performed in a common atmosphere used for printing, for example, in the same general (enclosed) chamber. In a second embodiment, a separate, fluidically isolated chamber is used for the measurement, for example as part of the service station area.

18A shows a layout of a droplet measurement system 1801 specifically configured to use shadow painting techniques. In particular, it is possible to see the printhead 1803 in the position where the droplet 1805 is ejected into a spitoon (not shown in FIG. 18A). During the flight of the droplet 1805, it can be seen that the droplet traverses the measurement area illuminated by the light source, and in FIG. 18A the light source consists of flashing light 1807 and optional light source optics 1809, The light source optics are used to direct light from the blinking light 1807 to the measurement area (eg, from below the measurement plane as previously illustrated in connection with FIGS. 2A-E or 16-17). The optics direct the light to illuminate the relatively large area indicated by focusing or redirecting the path 1811 and rapidly revealing droplets continuously and repeatedly at different locations for capture within a single image frame. Therefore, FIG. 18A shows three different positions of the same droplet and shows different flashes of blinking, which are imaged together collectively. Thus, for example, under analysis the image frame will show what appears to be a plurality of droplets at different locations (ie, for a plurality of examples of reference number 1805), but they are actually the same droplets at different locations along the flight trajectory. to be. The second set of optics 1813 provide light collection and focusing such that the captured image apparently exhibits varying amounts of shadows representing droplet contours and droplet diameters, which is image processing software for calculating droplet volume. Used by. As will be appreciated, by imaging the same droplet during flight of the droplet at multiple locations, the droplet measurement system can use one image to calculate the droplet volume, velocity, and trajectory, with the shadow parameter being the droplet mass, and thus the volume. The relative position of the droplets is used to calculate the velocity and trajectory. For example, at the “lower position” within the captured image frame, the droplets with increased apparent diameter are moved towards the light receiving optics 1813, and conversely, the droplets with reduced diameter are moved opposite the optical receiving optics. Light receiving optics 1813 eventually deliver the captured light to a camera 1815, such as a high-resolution CCD camera that images droplet contours and shadows. The droplet measurement system selectively controls the zoom / focus 1819 and / or XY position 1821 of the receiving optics, and the computer system 1823 (and the ratio used by one or more processors of the computer system for such control). Control all of the instructions stored on the temporary machine readable medium). In one embodiment, as mentioned, the receiving optics and light source are mounted on the camera chassis and moved together to provide a fixed focal path, but this need not be the case for each embodiment. The illustrated system captures the movement of each droplet in a few microseconds, while image processing application software 1825 is executed by computer system 1823 to calculate droplet parameters. By way of example, a computer may provide display and visualization 1827 of droplets and / or measured parameters, and calculate values for various or other parameters, such as volume, velocity trajectories 1829, 1831, and 1833. . Computer system 1823 may be part of an inkjet printing system or may be remote (eg, a local area network “LAN” or a wide area network “WAN” such as the Internet for collecting data on a remote basis), such as a display. And visualization 1827 may be provided at a location remote from computer system 1823, and may be provided over a LAN or WAN. As indicated by reference numeral 1835, computer system 1823 measures for a given nozzle that produced the droplet (and, for a given nozzle-waveform pairing, if an alternating drive waveform is used by a particular embodiment of the printing system). Compile the measured parameters to form a statistical group of. The computer system 1823 may store the individual measurements on its own and / or a statistical summary (eg, mean and standard deviation or variance in the case of a normal distribution, and comparable metrics if other types of variance are supported). Save it optionally). Once a sufficiently robust population is measured, the database can be applied to the planning and / or optimization of the printing process, as described above, for example, using a specific combination of droplet averages, so as to obtain a composite fill per target area. Synthetic filling can be based on different droplet volumes (eg, from different nozzles and / or drive waveforms).

18B shows a layout of a droplet measurement system 1851 specifically configured to use a PDA (interference measurement) technique. The printhead is shown in position for measurement, as indicated by reference numeral 1853. The printhead will eject droplets from a particular nozzle (eg, using a particular drive waveform) downward into the droplet measurement area, as indicated by reference numeral 1855. As in the previous embodiment, the droplet measurement system can optionally be designed for three-dimensional transport for a stationary printhead, such that the droplet measurement region effectively "brought to" the droplet flight path of a particular nozzle. A light source, in this case laser 1857, generates light rays 1859, which are directed to enter beam splitter 1861. The beam splitter produces two or more rays 1863 and 1864 (only two are shown in FIG. 18B), wherein the optical optics 1865 are redirected in a converging manner, ie, the rays are shown by reference numerals 1866 and 1867. Likewise, it intersects with the droplet in the position where it is in flight. Optical optics 1865 are optionally provided for the laser 1857 to be mounted below the measurement plane (see discussion of FIGS. 2D and 2E above), and optionally, to reach the measurement area, optical path 1859 or 1863. / 1864) (eg by redirecting one or more light paths around the periphery of the spitoon). Reference numeral 1869 denotes a general and continued dimension of illumination optics (eg, light paths 1866 and 1867). As noted previously, using an interferometry-based technique, the refractive pattern is captured from the directional angle offset to this continued dimension 1869, as represented by angle measurement 1873. This angular deviation is typically 90 degrees, but other capture directions may also be used. Thus, measurement light 1871 is received from incident light by a second set of optics 1875 (denoted as “optical 2”) and redirected to deposition-plane-measurement below by non-imaging detector 1877. These detectors generate data representing the refractive pattern, as shown by Figure 1879, and as recognized (eg, by contrasting Figure 1817 and Figure 1879 in Figure 18A), the spacing of the lines in the refractive pattern. Provides a measure of droplet volume, which spacing processes the droplet volume much faster than the imaging technique represented by FIG. 18A. Although FIG. 18B illustrates the use of one light source 1857 and two incident lines 1866 and 1867, other embodiments may include one or more light sources and two or more light sources, for example, to capture droplet velocity, trajectory, and other parameters. Use an incident line. As with the embodiment of FIG. 18A, in FIG. 18B, the computer 188 optionally provides XY transfer of zoom / focus 1883 and measurement optics, and executes appropriate application software 1887 to calculate various droplet parameters. And provide display and visualization 1889. As before, these various elements may be integrated with lsthorl or manufacturing devices and distributed across a WAN or LAN controlled by a plurality of separate processors of respective computers or servers. As before, the measured parameters may include droplet volume 1891, velocity 1893, and trajectory 1895, with data representing statistical population 1897 stored in database 1899 for purposes of scan planning. . This scan scheme once again combines droplet parameters from various nozzles and / or waveforms to intentionally perform accurate filling of the target area based on a plurality of different droplet volumes.

It has been previously mentioned that the droplet parameters may change over time depending on system parameters, ambient conditions or ink properties, for example. Therefore, the industrial printing system preferably updates the droplet population of the statistical population relatively frequently, preferably for each droplet (and the expected average volume / speed and trajectory of each droplet) rather than a single droplet, which is always accurate and up to date. It helps to ensure accurate droplet data and allows for planned droplet combinations to reliably conform to maximum tolerances for synthetic ink filling. In fact it can be seen that the droplet parameters change somewhat slowly, for example as detectable deviations every 2 to 12 hours. The use of in-situ droplet measurement can iteratively perform dynamic measurements and the construction of new statistical populations of measured parameters within a time range, and with conventional techniques, many times to measure bulk printheads or printhead assemblies. However, through the use of a fast technique such as the PDA discussed above, it is possible to update all statistical measurements very quickly, such as within 30 minutes, even if thousands of print nozzles are involved. Therefore, a system using some or all of the techniques discussed above enables an industrial press with droplet measurement parameters recalibrated based on statistical distribution within the mentioned 2 to 12 time frame, thus providing target area fill variation. This allows for more accurate printing within the maximum tolerance for.

As noted previously, in one contemplated embodiment, the press is controlled intermittently or continuously, performing drop parameter measurements at any time the press is activated and not printing. This maximizes uptime of the manufacturing line. As mentioned, in one embodiment, at any time when the printhead assembly of the printer is not used, the printhead assembly can be switched for droplet parameter measurement. For example, at any time the substrate is loaded or unloaded, evolved, dried, cured or processed between the chambers, the print carriage can transfer the printhead assembly to the service station for droplet measurement and / or other service operations. . This operation helps to provide more frequent and dynamic updates of the droplet statistics population for each nozzle, as described, and optionally, PDA-based droplet measurement devices (eg, interferometry-based techniques). This control scheme can serve as a droplet measurement task that is transparent to any desired print job. In the system under consideration, such control is executed by a control system running on at least one processor that manages the printing process, and such software may be on a printer, one or more computers or servers, or both.

19 shows an example 1901 of flow for such a control process. As mentioned, this process, when executed, may optionally be executed by instructions stored on a non-transitory machine-leadable medium, which allows at least one processor to perform / provide the listed steps.

19 is divided into three general areas 1901, 1905, and 1907, respectively, which illustrate startup and offline initiation processes, online printing, and offline specific operations. As the system is powered on, the system typically becomes an initiation process 1909 where new measurements are taken for each nozzle to express a statistical population, as described above. At the same time, a calibration process (not shown) may also be requested to select a plurality of nozzle spray waveforms for each nozzle (e.g., select 16 waveforms to produce droplet volumes within ± 10.0% of the target droplet volume). Using a repeating process, as previously described). Therefore, a statistical population is expressed for each such waveform and / or nozzle, including the average droplet volume as well as the desired spread. As noted previously, in one embodiment, a fixed number of measurements is performed for each droplet, while in another embodiment the number is variable between nozzles (or per nozzle-wave pairing), so that A tight statistical spread is achieved and, in one embodiment, the validity or qualification process is where a nozzle (or nozzle-waveform pairing) that does not produce droplets with the desired parameters may be disqualified from use in the printing plan. Can be applied as an option. The measurements and / or statistical measurements are then stored (1911) as applicable for each nozzle and each nozzle-waveform pairing. This startup calibration can be performed at the very first time, the system is turned on (eg, in a single fashion), and in another embodiment, a new power up of the system is performed every hour. For example, it may be desirable to store previously calculated droplet parameters (and update these parameters in accordance with the process discussed below) (if the production line is run only during a portion of each day). Alternatively, new parameters can be calculated anew for each power cycle.

The system also optionally automatically schedules the scanning process 1915 and the parameter and droplet combinations that form the printing process and substrate parameters 1913, as previously described. For example, in other contemplated embodiments where a printing press is part of an assembly line for a particular OLED display product, these parameters and schemes may not change. However, if the droplet parameters can change, the printing press plan can also change, and therefore, the process 1915 can optionally re-execute statistical parameter changes at any time, as an automated background process, each time The droplet measurement system is connected (as indicated by figure number 1917).

With system printing parameters and averages available for droplet parameters (ie, for each nozzle or nozzle-waveform pairing), the system can enter an online mode, where the system prints as desired, for Figure 1919. Do this. In other words, the substrate can be loaded and also transferred into the printing press so that printing one or more OLED device thin film layers can be performed as desired. However, to minimize device downtime, each time of printing is stopped (e.g., to load or unload a substrate), and the various printhead nozzles update the droplet measurement, intermittently or periodically to collect statistical droplet populations. Update. For example, a typical printing process for a large HDTV substrate (representing several large sized TV screens) can be completed within about 90 seconds, and then the substrate under consideration can be unloaded, for example a process that takes 15-30 seconds. It is anticipated that one may go to another chamber 1920 during this time. During this 15-30 second pause time, the printer is not used to print, so droplet measurement can be performed at this time. For example, the control software for the printing press controls the substrate transfer means to move the old substrate from outside of the printhead carriage, while the control software services the printhead assembly for droplet measurement and / or other service functions. Move to the station. As soon as the printhead assembly is stopped (1921), the control software is selectively connected to a droplet measurement system, for reference numeral 1923, to perform droplet measurement. As noted previously, the measurements can express statistical populations for droplets produced by various nozzles or various nozzle-waveform pairings. To make up for previously stored measurements, the droplet measurement system is operated in a loop and as many droplet measurements as possible until the next substrate is loaded or printing is resumed. For example, for functional blocks 1925, 1927, 1929, and 1931, a droplet measurement system may (1) measure a plurality of droplets for a given nozzle or nozzle / waveform pairing, and (2) store the results in memory or Update (i.e. store new and additional measurement data as raw data, store updated average or statistical summaries, or both), or (3) identify nozzle addresses (or nozzle-waveform identifiers for subsequent measurement cycles). Or (4) as appropriate, with another nozzle or nozzle-waveform pairing for another set of measurements. The process of loading / unloading a substrate potentially results in varying amounts of time, so that when the system is ready for a new print cycle, the control software issues an interference or function call 1933 to properly service ( 1935 is separated (eg, including a droplet measurement system) and the printhead assembly is returned to active printing (1919). As mentioned, the control software explicitly updates or recalculates the droplet combinations, which are no longer valid because of updates per nozzle droplet average. Because the droplet measurement loop stores the address or location for subsequent measurement cycles 1930, the system uses nozzle / nozzle-waveform pairing in a circulating manner, with thousands of different nozzle / nozzle-waveform pairings available for use in generating droplets. Droplet measurement is effectively performed for a small window of droplet processing. Printing is then performed until the next substrate iteration is complete, at which time the substrate is unloaded and the measurement / service cycle continues. As described after other press operations, by stacking droplet measurements, these techniques can substantially help to substantially reduce system downtime, that is, to maximize manufacturing throughput. Although the method shown relates to a droplet measurement system with all load cycles, it is not necessary for all embodiments, i.e. it may be desirable to update the droplet measurement at a particular speed (eg every 8 hours) and If the droplet statistical population is formed more quickly using the mentioned stacking operations, it may be desirable to perform different service operations instead during substrate loading and / or transfer and / or curing operations. 19 also shows a special maintenance box 1937 associated with the need to change a particular ad-hoc action, such as a printhead or another offline process.

As can be seen, the mentioned technique enables high uniformity in the manufacturing process, in particular in the OLED device manufacturing process, thus improving the reliability. These techniques, in some embodiments, are at least partially possible using droplet measurement techniques that enable Mura suppression through the use of precise droplet combinations and dissimilar nozzle combinations and droplet volume combinations. Furthermore, in particular regarding stacking these measurements for other system processes in a calculated manner to reduce the speed of droplet measurements and overall system downtime by providing control efficiency, the disclosure set forth above provides flexibility and accuracy in the manufacturing process. It helps to provide a faster, cheaper manufacturing process designed to provide all.

In the foregoing description and the accompanying drawings, specific terminology and reference numerals are provided to provide a thorough understanding of the disclosed embodiments. In some cases, terms and symbols may refer to specific details that are not necessary to practice these embodiments. The terms "exemplary" and "embodiment" are used to express an example that is not a preference or requirement.

As indicated, various modifications and variations may be made to the embodiments shown herein within the broad spirit and scope of the invention. For example, a feature or aspect of some of the embodiments may be applied and, when implemented at least, may be applied in place of its opposite feature or aspect, in combination with any other of the embodiments. have. Thus, for example, all features do not appear in each and every figure, and for example, features or techniques that appear in accordance with embodiments of one figure and for example one figure, although not specifically mentioned herein. It should be contemplated that the features or techniques shown in accordance with an embodiment of is optionally available as elements of any other figure or embodiment of the features. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims (23)

In an apparatus for making a permanent layer on each substrate, each permanent layer and each substrate forms part of a respective electronic device, the apparatus comprising:
A print head having a nozzle;
Substrate transfer means for successively transferring each of each of said substrates to and from a printing position where each of each substrate can be printed by a printhead;
When in the printing position, the printhead is between a first position where the printhead can print each droplet of liquid on each substrate and a second position where the droplet cannot print on each substrate. Printhead conveying means for conveying; And
A droplet measurement system comprising a light source, a photo detector and a light path extending from the light source to the photo detector 280, wherein the light source is positioned adjacent to the second position, the light source being positioned at the second position. Located outside the side of the printhead, the light source, the light detector and the light paths are mounted in a fixed positional relationship with respect to each other, the light detector measuring a droplet characteristic of the liquid jetted from one nozzle during droplet flight. Providing an indicative electronic output, said electronic output being dependent upon detection of an interference pattern from the interaction of flying droplets with light rays from a light source,
The apparatus further comprises third conveying means for moving the droplet measurement system in at least two independent dimensions with respect to the printhead to dispose an optical path and intersect the flight path of droplets ejected from the nozzle. Device for making a permanent layer on each substrate. The method of claim 1, further comprising a third transfer means for moving the droplet measurement system in at least two independent dimensions with respect to the printhead. Device. 3. The apparatus of claim 2, wherein the third transfer means causes the droplet measurement system to move in at least three independent dimensions with respect to the printhead. 4. The apparatus of claim 3, wherein the three independent dimensions comprise an extended length between the nozzle and the interaction point of the droplet and the light beam. The apparatus of claim 1, wherein the characteristic is one of trajectory or velocity, and the electronic output varies depending on the trajectory or velocity of the droplet. 2. The apparatus of claim 1, wherein: the nozzle defines a first plane, and the droplet measurement system further comprises a mirror;
The light source, the light detector, the mirror and the light path are all mounted in a fixed positional relationship with respect to each other;
The third transport system moves the droplet measurement system in at least two dimensions to move segments of the optical path along a second plane, the second plane being parallel to the first plane; and
Wherein each of the light source and the photo detector is disposed outside the second plane. 7. The apparatus of claim 6, wherein the photo detector detects an interference pattern, and wherein the apparatus further comprises at least one processor to calculate a value for the droplet feature based on the electronic output. Device for making a permanent layer on a substrate. The apparatus of claim 7, wherein the nozzle comprises at least one thousand nozzles, and
Said third transport means moving said segment while said printhead is in a second position such that said segment intersects the flight path of droplets of liquid ejected from any of at least one thousand nozzles. Apparatus for making a permanent layer on each substrate. 9. The method of claim 8, wherein the third conveying means is to move the droplet measurement system to at least three independent dimensions with respect to the printhead while the printhead is in a second position, And a distance between one intersection point and one nozzle between the flight paths. The method of claim 1,
The nozzle comprises at least a thousand nozzles,
The third conveying means moves the droplet measuring system in at least two independent dimensions with respect to the printhead,
Arrange the light path to intersect the droplet flight path of liquid injected from any of at least a thousand nozzles, and
Wherein the apparatus further comprises a non-transitory reservoir for storing a value for each feature of the nozzle. 10. The apparatus of claim 9, wherein the light source is a laser. The method of claim 1,
The droplet measurement system further includes a collector for droplets ejected from the nozzles while the optical path is arranged to intersect the flight path of the droplet, such that the droplet measurement system is arranged to intersect the flight path. When such nozzles cause the droplets to spray toward the collector, and
Wherein the light source, the light detector, the collector and the light path are mounted by the droplet measurement system in a fixed positional relationship with respect to each other. The method of claim 1,
And the apparatus further comprises an environmental enclosure for maintaining a controlled atmosphere, wherein the print position and the first position lie in the environmental enclosure. The apparatus of claim 1, wherein the liquid comprises a liquid monomer. 2. The method of claim 1, wherein the printhead conveying means, the droplet measuring system and the third conveying means are automatically controlled and characterized for droplets from at least one of the nozzles in the middle of printing of the liquid onto successive substrates. Further comprising an electronic control system for automatic measurement. 2. An apparatus according to claim 1, wherein said printhead conveying means comprises a bridge extending above said substrate conveying means. 18. The apparatus of claim 16, wherein the second location is at the end of the bridge. A print head having a nozzle;
Substrate transfer means for transferring a substrate to a print position adjacent the print head;
Printhead conveying means for conveying the printhead between a first position and a second position, the printhead capable of printing each droplet of liquid onto a substrate positioned at the print position;
A droplet measurement system, positioned adjacent to the second position, comprising a laser, a photo detector, and a light path extending from the laser to the photo detector, wherein the laser, the photo detector, and the light paths are fixed relative to one another. Having a positional relationship, said photodetector comprising: said droplet measurement system providing an electronic output indicative of an interactive interference pattern measurement of light rays from said laser and droplets ejected from one nozzle during droplet flight; And
Third transport means for moving the droplet measurement system in at least two independent dimensions relative to the printhead to dispose an optical path and intersect the flight path of droplets ejected from any of the nozzles; , An apparatus for fabricating a permanent layer on each substrate. 19. The apparatus of claim 18, further comprising a processor for determining the droplet characteristics from the electronic output. 20. The apparatus of claim 19, wherein the feature is volume, trajectory or velocity. 21. The method of claim 20, wherein the third conveying means conveys the droplet measuring system to at least three independent dimensions of the printhead, and includes a length extending from one of the nozzles and the intersection of the optical path and the droplets. And a permanent layer on each substrate. 19. The fabrication of a permanent layer on each substrate of claim 18, further comprising a collector having a fixed positional relationship with the laser and light combiner to receive droplets ejected from the nozzle. Device for. 19. The apparatus of claim 18, wherein the nozzle defines a first plane, the third conveying means moves a light path segment that intersects with the droplets flying within the second plane, and wherein the laser and the detector each comprise the second. Positioned outside the plane, for producing a permanent layer on each substrate.

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