TW202243919A - Method and system for measuring a parameter - Google Patents

Abstract

A droplet measurement system (DMS) is used in concern with an industrial printer used to fabricate a thin film layer of a flat panel electronic device. A clear tape serves as a printing substrate to receive droplets from hundreds of nozzles simultaneously, while an optics system photographs the deposited droplets through the tape (i.e., through a side opposite the printhead). This permits immediate image analysis of deposited droplets, for parameters such as per-nozzle volume, landing position and other characteristics, without having to substantially reposition the DMS or printhead. The tape can then be advanced and used for a new measurement. By providing such a high degree of concurrency, the described system permits rapid measurement and update of droplet parameters for printers that use hundreds or thousands of nozzles, to provide a real-time understanding of per-nozzle expected droplet parameters, in a manner that can be factored into print planning.

Description

Systems and methods for measuring parameters

The present invention relates to rapid measurement of droplet parameters in industrial printing systems.

More and more industrial processes are turning to printing systems for manufacturing product stacks. These printing systems deposit a fluid that is then cured or hardened to form a permanent laminate for a particular product. Such processes are particularly useful for microelectronics or products with arrays of quasi-electronic structures. For example, such printing processes are increasingly used to manufacture thin-film electronic displays and solar panels for a wide variety of applications. In addition to the type of fluid ("ink") used, the aforementioned printing systems are typically characterized by the use of thousands of printing nozzles on one or more print heads, which are designed to have near-micron resolution The ability to achieve individual, approximately uniformly sized droplets. This precise control of both the volume and position of the deposited droplet contributes to high quality end products as well as high resolution, small size products and reduced manufacturing costs. In one application, for example, the manufacture of organic light emitting diode (OLED) displays, the ability to precisely deposit ink can help produce smaller, thinner LEDs at lower cost. , and better-resolution displays. Note that when the term "ink" is used to refer to a depositing fluid, the depositing fluid is essentially colorless and is deposited into a structure that will "build" a permanent stack of devices one thickness, meaning That is, the color of the fluid itself is generally not important in the sense that inks are used in traditional graphic printing applications.

Not surprisingly, in such applications, quality control is dependent on the uniformity of the deposited ink droplets, both in size (drop volume) and precise location, or at least the understanding that it is important to be able to produce consistently satisfying stacks. For permanent stacks of quality standards in layer alignment accuracy and/or stack homogeneity, variations in these characteristics are important. Note that in an industrial printing system, drop uniformity for any particular nozzle also has the potential to vary over time, whether due to statistical variation, changes in nozzle age, clogging, ink viscosity or compositional variation, temperature, Or other factors are possible.

What is needed is a droplet measurement system adapted for use with an industrial printing process, ideally in situ with a printing system used by an industrial manufacturing facility. Ideally, such a drop measurement system would provide remarkably fast measurement of one or more drop parameters, be easy to maintain, and provide inputs that can be used to adjust printing, thereby enabling precise quality control for industrial product manufacturing among. The present invention addresses these needs and provides other related advantages.

According to one aspect of the present invention, a system for measuring parameters associated with droplets ejected by a plurality of nozzles of a printhead is disclosed. The system includes: a film having a first side and a second side, the first side to be positioned near the printhead to provide a substrate for receiving ink droplets from the plurality of nozzles; an imaging subsystem, positioned to capture an image through the second side of the film, the image representing ink droplets received from nozzles located at respective positions of the nozzles, the image capturing subsystem for generating an output signal to convey the captured image to an image processing system; and a mechanism for advancing the film to position an entirely new portion of the film for a subsequent image capture process, wherein droplets from a plurality of nozzles of the printhead are received on the first portion of the film Above that, advancement of the film does not require repositioning of the print head or the imaging subsystem.

According to an aspect of the present invention, a method for measuring a droplet parameter is to measure a parameter related to a droplet ejected by a plurality of nozzles of a printing head. The method includes: providing a film having a first side and a second side, and positioning the first side near the printhead to provide a substrate for receiving ink droplets from the plurality of nozzles; using an image capture device capturing an image through the second side of the film, the image representing the ink droplets received from the nozzles at respective positions of the nozzles, and correspondingly generating an output signal for delivering the captured image to an image processing system; and Advancing the film to position an entirely new portion of the film for a subsequent imaging procedure wherein droplets from the plurality of nozzles of the printhead are received on the first side of the film in a manner that does not require the printhead or The image capture device is repositioned.

According to an aspect of the present invention, an apparatus includes: a printing machine for receiving a first substrate, the printing machine has a printing head, the printing head contains a plurality of nozzles, and the plurality of nozzles are used to eject an ink on On the first substrate, the ink comprises a liquid that is to be hardened on the first substrate to form a permanent stack of an electronic device thereon, the permanent stack of the electronic device having a thickness; and a system for measuring a parameter associated with droplets ejected by the plurality of nozzles of the printhead. The system includes: a film having a first side and a second side, the first side to be positioned adjacent the print head to provide a second substrate to receive ink droplets from the plurality of nozzles; an image capture sub a system positioned to capture an image through the second side of the film representing ink droplets received from nozzles located at respective positions of the nozzles, the image capturing subsystem for generating an output signal to capture the image the image is delivered to an image processing system; and a mechanism for advancing the film to position a fresh portion of the film for a subsequent image capturing process, wherein droplets from the plurality of nozzles of the printhead are received on the film Advancement of the film does not require repositioning of the print head or the imaging subsystem over the first side.

In one embodiment, a drop measurement system receives ink droplets from various nozzles of one or more printheads and then uses optical analysis to measure the associated various droplets and/or the various printhead nozzles that produced them. One of the values of one of the parameters. More specifically, as will be described below, some embodiments use a deposition tape located in a printer service bay for test printing with ink from various nozzles simultaneously. The tape may in an advantageous embodiment be any medium capable of receiving ink droplets, and in a notable embodiment described below, it comprises a transparent film specially treated to immobilize wet ink droplets, Much like photosensitive photo paper. Also, in one embodiment, the system is used in an industrial manufacturing facility where the droplets to be deposited are themselves transparent or translucent (e.g., representing a material that will be deposited and cured to form a panel An encapsulating layer of a device such as a display or a solar panel, or the light emitting element of such a device). This transparency enables imaging of groupings of one or more droplets for a set of multiple nozzles; in an alternative embodiment, droplet deposition can be associated with both the membrane and the position of the imaging nozzle (located behind the membrane) are spaced from each other to provide very fast measurements of drop position offset (relative to ideal drop position) and/or volume and/or timing errors associated with drop deposition.

In one embodiment, one or more printheads are parked at a service station in order to take measurements, for example, while a substrate is being loaded or unloaded into the when the equipment is used for other purposes). When the printhead is parked, it engages the drop measurement system in a manner that is aligned at a specific position relative to one or more printheads to bring the deposition medium (eg, the transparent film described above) into the one or more printheads. near the print head. It then causes nozzles from one or more printheads (e.g., a window or subarray containing a subset of all nozzles) to fire a drop or a train of drops (e.g., 2, 5, 10, etc.), The droplets are caused to land on the media at a desired location near a particular nozzle. During this period, or after this period, the film is imaged from the side of the film opposite the print head, effectively across the transparent film; in other words, the film is precisely positioned at a normal deposition distance relative to the nozzle being measured (e.g., < 1.0 mm), and the nozzles are measured simultaneously (or shortly thereafter) by simultaneously firing the nozzles, and then by taking an image through the other side of the film, the resulting captured image is then Image processing to obtain droplet parameter values.

Some advantages of the features of the various embodiments described so far are noted below. First, the described optical processing of deposited droplets through a transparent film is particularly suitable for very large print heads with hundreds to thousands of nozzles, i.e. the optical processing can be performed immediately without additional shifting of the printing head, droplet measurement system or other components. Second, droplet measurement systems can be configured to simultaneously measure droplets from multiple nozzles; for example, it is possible to eject droplets from hundreds of nozzles and measure them simultaneously. When compared to systems that optically image individual droplets in flight (e.g., one drop at a time), such simultaneity can greatly facilitate the processing of thousands of printhead nozzles (e.g., as used in some industrial manufacturing) Droplet measurement between applications). For systems that rely on dynamically updated measurements of droplet parameters, this simultaneity can be important in order to combine droplets in a way that mitigates variability or compensates for variations that produce precise target volumes, since it does not require significant changes in printing time or manufacturing. There was a notable disruption in output. For a drop measurement system linked to one or more parked printheads located in a service station, this provides easy access to any of the thousands of print nozzles that can be used in some industrial processes and precise use. Also, the deposited film strip or its processing can be specially tailored to match the chemical properties of a particular ink to be tested (ie, so that its properties can be more easily and accurately determined by optical mechanisms). It should be apparent that the described techniques provide enhanced accuracy and lower cost for the manufacture of products, for example, especially for price-sensitive consumer products such as flat-panel high-definition televisions ("HDTVs").

In at least one design described below, the droplet measurement system described above utilizes a roll-to-roll mechanism to load a transparent film that allows the film to be advanced over an imaging area as a roll of film, allowing for Intermittent replacement of film tape rolls for measurement. In addition, the droplet measurement system may also advantageously use a vacuum system that closely adheres to the portions of the strip being deposited forming a flat and precise positional relationship with each other, simulating a deposition surface for in-line use. The drop measurement system may also optionally include a curing station to cure/air-dry the ink so that after measurement, additional ink is inhibited from spreading to any other part of the system; note that this is not a requirement in some embodiments. Necessary, for example, the film may also be selected or treated to possess properties such that the ink droplets are immobilized once deposited. Furthermore, as previously mentioned, the droplet measurement system can optionally be mounted on a three-dimensionally movable carriage, in other words, to engage a parked printhead from below along a vertical (V) axis, and Move along the x (and optionally y) axis as needed to reach different nozzles and different print heads. This allows a "large" printhead assembly (e.g., one with tens of thousands of nozzles) to be attached below a printing plane (e.g., in an access bay) and used with the aforementioned drop measurement system. To keep fixed while measuring the parameters of different groups of nozzles. A conceived deposition process advances a roll of film such that a window of unused film is adjacent to selected printheads, which are then controlled so that all of their nozzles eject a specified amount of ink, which are then affixed to the at the same time, a coaxial camera from below (e.g., within a housing or chassis of the droplet measurement system) images all deposited droplets in parallel with the image sensor (again, by passing through the Imaging of an opposite side of the membrane strip allows essentially neither the thin film nor the droplet measurement system to be moved or repositioned for analysis). If desired, the camera (or image capture optics) can be configured to be movable relative to the droplet measurement system, for example, to provide scanning motion between a range of nozzles, focus adjustments, or other desired assistance .

The output of an image processing system then provides drop parameter data suitable for validating nozzles or otherwise planning printing. Immediately after any particular measurement iteration step, the tape and drop measurement system are each advanced into position, the tape used is cured and/or rolled, and the process is repeated immediately as needed, or at a later time Click repeat. In designs where the film cannot be reused once printed, a used film roll (or a film cassette with spools and capstans for new and used film) can be Groups are periodically recycled or replaced on a group basis. Note that in a contemplated application where a fabrication facility is used sequentially (for example, to print a stack of OLED television screens, or otherwise fabricate a stack of one or more flat panel devices), when a previously The substrate is unloaded, the print head is parked for the aforementioned drop measurement, and as soon as a new subsequent substrate is ready, the measurement progress is stored, the print head returns to the active print job, etc.; when this subsequent substrate is completed , the print head returns to the service station again (when a new substrate is loaded) as such to start the measurement where the system previously stopped. In this way, repeated measurements can be collected for nozzles and used on a rolling basis to create a statistical distribution for each printing nozzle or combination of nozzle waveforms over many measurements (eg, as in the patent application in the priority claim , which are incorporated herein by reference), use a moving measurement window that advances cyclically through all print nozzle sets to continuously update the measurement data.

Note that all of the process steps listed above (and below) can be implemented in various ways. For example, in one embodiment, the steps are performed by one or more computers or other types of machines (such as a printing press or one or more manufacturing devices). For example, in one contemplated design, one or more jobs may be performed by one or more of these machines in a program stored on a non-transitory machine-readable medium, such as firmware or Actions under the control of software instructions. The instructions are written or designed in such a way that they have a specific structure (architectural characteristics) such that when the instructions are ultimately executed, they cause one or more general-purpose machines (such as processors, computers, or other machines) to behave Be like a special-purpose machine having the structure necessary to perform the described tasks on input operands, to take actions, or to otherwise produce output. "Non-transitory machine-readable medium" means any tangible (i.e., physical) storage medium, regardless of how data is stored thereon, including, but not limited to, random access memory, hard disk memory, optical Memory, floppy disks or CDs, server storage, volatile memory, and other tangible mechanisms where instructions can be later retrieved by a machine. The machine-readable medium may be in stand-alone form (e.g., a program disc) or implemented as part of a larger mechanism, such as a laptop, portable device, server, network, printing press, Or other device sets consisting of one or more devices. The instructions can be implemented in different formats, for example, as metadata that effectively invokes a specific action when invoked, as Java code or scripts, as code written in a specific programming language (eg, implemented as C++ code), implemented as a specific processor instruction set, or implemented in some other form; these instructions may also be executed by the same processor or different processors, depending on the embodiment. Throughout this disclosure, various processes will be described, any of which can be implemented substantially as instructions stored on a non-transitory machine-readable medium, and any of which can use a "3D Print" or other printing process to manufacture products. Depending on the product design, these products may be manufactured in a salable form, or as a preliminary step to other printing, curing, manufacturing or other processing steps that will eventually result in a finished product for sale, distribution, export or import. Depending on the implementation, the instructions located on the non-transitory machine-readable medium may be executed by a single computer, while in other cases may be stored and/or executed on a distributed basis, for example, using one or Multiple servers, network client devices, or application-specific devices. Each of the functions described can be implemented as part of a consolidated program or as a separate module, stored together on a single media form (e.g., a single floppy disk), or stored on multiple separate storage devices .

In addition, it should be noted that the word "transparent" is a relative term when used in conjunction with a film or a film, that is, it means that the film is deposited on the first side of the film through the second side of the film. Image of the droplet above. Strictly speaking, this does not mean that the tape must be colorless, or, for that matter, transparent to visible light. In one embodiment, the film is colorless and highly transparent to visible light, and the visible light is used to take images of the droplets from the respective nozzles deposited in such a way that the respective nozzles The droplets are arranged in an array on the first side of the film strip (ie, at respective locations associated with respective nozzles). In another embodiment, the tape has a certain color, for example, optimized for a particular ink to enhance the image-capturing properties of the ink. In yet another embodiment, radiation rather than visible light is used to photograph droplet properties.

Various other features will be apparent to those skilled in the relevant art from the description herein. Having briefly outlined the features of some embodiments, the disclosure below turns to providing further details on selected embodiments.

Figure 1 shows a flowchart 101 illustrating some of the techniques described herein. As previously indicated, it is necessary to simultaneously measure the values of the droplet parameters of the droplets produced by numerous nozzles. To perform this action as quickly as possible, embodiments disclosed herein rely on image capture of a deposition surface that receives the droplets (that is, a rapid image capture of the droplets collectively representing the plurality of nozzles), and from this image capture Image processing is performed to calculate one or more desired parameters respectively relative to the plurality of nozzles. As indicated by reference numeral 103, the one or more printheads under analysis cause a range of nozzles or an array of nozzles to fire, each depositing one or more droplets. For example, it may be the case that a hypothetical print head has two thousand nozzles, and these nozzles are scheduled to be measured simultaneously in groups of one hundred nozzles. For each measurement iteration step, the printhead and/or drop measurement system is aligned and a window or grouping of one hundred nozzles to be measured is identified and caused to fire a controlled amount of ink approximately simultaneously ; In one embodiment, the above-mentioned deposition can be a single droplet per nozzle, while in other embodiments, each nozzle can be controlled to eject a larger number of droplets, for example, 2, 5, 10, 12, 20 or other number of droplets. Note that in some contemplated designs (e.g., OLED applications), the droplet size is often quite small, including picoliter (pL) sized droplets with a diameter factor of ten microns or less, with close to micron precision deposition.

As described in the patent applications incorporated herein by reference in the priority statement, depending on the application, it may be necessary to measure the position of the deposited drop, the velocity of the drop, the volume of the drop, nozzle warpage, or one of each nozzle. or multiple other parameters. In short, in one embodiment, for each deposited droplet, the drop quality of each nozzle can be expected to be of importance; that is, if one nozzle is This can produce non-uniformity in a deposited film if it is in a stop position (nozzle warping) or produces off-track drop trajectories or an inaccurate drop volume. This unevenness may cause quality defects on delicate products such as display devices. Knowing this defect on a nozzle-by-nozzle basis makes it possible to:

Nozzle pass/fail: It can identify nozzles that are not working or have other bad characteristics and exclude them from the printing job, where the software-planned printing method can use a different nozzle to deposit a droplet in a predetermined area;

Firing time mitigation: positional imperfections in the scan direction can possibly be corrected by changing the nozzle drive pulses with respect to timing or voltage, for example, making the nozzle fire earlier or later, or at a greater or lesser velocity jetting; in addition, it is also possible to use alternating drive pulse shapes, as disclosed in the patent applications incorporated herein by reference in the priority claims.

Predictive droplet composition: Detected differences between nozzles can be accepted and deliberately used to calculate droplet composition according to respective desired values to achieve an accurate result, e.g., within a specified tolerance; For example, if one nozzle is measured and judged to produce the expected 9.89 picoliter (pL) droplets, a second nozzle is measured and judged to produce the expected 10.11 pL droplets, and it is expected to produce the total volume of 20.00 pL of ink at a specific target location, then the two nozzles can be specifically designated and programmed to print to deposit this particular combination of droplets; note that the results that can be obtained are different from those obtained by simply averaging the differences and disregarding the Systems with specific fill levels or fill tolerances (e.g., ±0.50% target volume); and

Pre-screening of drive waveforms: As shown in the patent applications incorporated herein by reference in the priority statement, it is possible to pre-screen the programmable drive waveforms for each nozzle (e.g., a selection from sixteen pre-selected drive waveforms ) for inventory during printing, which selects each waveform to achieve a specific deposition characteristic, accuracy, and desired result.

Note that droplet parameters may vary from day to day, and even from deposition to deposition, eg, depending on ink quality, temperature, nozzle age (eg, clogging), and other factors. To ensure printing accuracy, therefore, in some embodiments it may be necessary to re-measure these values from time to time. It should also be noted that each deposited droplet may be slightly different, even from a single nozzle; thus, in one embodiment, each nozzle (or combination or pair of nozzle waveforms) is measured more than once, but Multiple times to accumulate the total number of measurements, from which an average or other statistical parameter (eg, a spread measure) can be calculated to provide a high confidence in the relative expected value of the droplet parameter. For example, it can measure "24" drops from each nozzle-waveform pair to average volume, velocity, warp (position orthogonal to the scan direction), etc. (and thus obtain these items One of the expected values), where the number of measurements n (n=24) helps to reduce uncertainties due to measurement errors or statistical variations. It can be on a rolling basis (e.g. all measurements are stored, with the 6 newest measurements per nozzle replacing the 6 oldest every two hours) or on a one-time basis (e.g. during power-up re-measure all nozzles at once) to update specific measurement totals. Those skilled in the art will envision many variations. For example, a nozzle can be measured to determine a desired value, and if the measured (expected) value is outside the ±5% band of a desired value, the nozzle loses Qualifications used; many permutations and variations are obviously possible.

However, it should be apparent that in a printing system using thousands of nozzles (e.g., tens of thousands or more, each perhaps with multiple "pre-screened" drive waveforms available), each Measuring the expected droplet parameters of a nozzle can be time consuming; in an industrial manufacturing environment, this is often unacceptable, in other words, the manufacturing throughput and cost required to produce the product is to be commercially viable Must be at an acceptable consumer price point, and this usually means that the printing process produces as much product as possible, with as high accuracy (and less product waste) as possible, and with as little print as possible downtime. The techniques disclosed in this paper enable much faster measurements and thus more feasible measurements.

Returning to FIG. 1 , in order to achieve this effect, the droplet measurement technique proposed in this disclosure also shoots droplets from many nozzles at one time, reference numeral 105 . In other words, embodiments of the present disclosure rely on simultaneity to measure as many nozzles as possible simultaneously, in contrast to systems that image droplets in flight "one at a time". Thus, image capture can be used to efficiently obtain an image from a large array of nozzles containing many droplets, eg, droplets deposited in rows and columns, which can be rapidly processed in software by an image processing system. In one embodiment, a captured image may represent droplets from dozens of nozzles, and perhaps hundreds of nozzles (or more), all measured simultaneously. Figure 1 shows in dashed boxes various options that can facilitate this goal, for example, (a) taking an image (107) through the deposition surface on the opposite side of the printhead, which facilitates velocity measurements, (b) Both the droplet and the nozzle are captured simultaneously in the captured image (109), which assists in the measurement of positional offset, warpage, or velocity of the droplet from the respective nozzles, (c) simultaneously ) nozzles for photographing (111), e.g., actually measuring forty or more nozzles at a time, and (d) not photographing one drop per nozzle, but simultaneously measuring a single drop containing multiple (e.g. , 5 or more) a collection of droplets. Note that in the latter case, image processing software can detect the volume (e.g., volume) of a pooled deposit, or the range of droplet locations around an expected location, and can identify individual droplets, mean, or other statistical parameters such as distribution (distance). Note that, depending on the embodiment, this may require a standard to be pre-measured and stored in the system; for example, it may be difficult to detect ink droplets when they are immobilized in the deposition medium (i.e., film strip). Measure droplet volume; this determination can be made for droplet diameter, the processing of the color (or gray scale) value of a deposited droplet, or the way it is used to determine, and use these values to compare with a calibration standard to produce accurate numerical estimate of .

As indicated at 115 and 117, the system (e.g., using a video processor running appropriate software) then calculates the measured values and stores them in memory (e.g., such as in an accessible hard drive random access memory). In one embodiment, these values are stored individually (that is, once for each measurement of each parameter to be measured for each nozzle), while in another embodiment it can be stored in a Stored in a manner representing a mixture distribution (eg, as a mean, total number of measurements, standard deviation, etc.) of a particular parameter for a particular nozzle. Referring to numerals 119, 121 and 123, as previously described, the measured values can optionally be used to calculate a statistical distribution, to perform nozzle qualification/validation, and to perform "smart combinations", wherein Print scans are programmed to match droplets with expected properties in some desired way.

2-4B are used to depict one embodiment of a modular droplet measurement system.

FIG. 2 shows a close-up view of a first such system 201 . This view depicts a measurement window 203 (eg, a glass-covered viewing window) through which images are taken along a vector indicated by reference numeral 205 . An optical detector, such as a camera, is located inside the system 201 and takes pictures through the window 203 in the direction of the arrow 205 . During operation, a strip of transparent film film from roll 207 is advanced over this window and held against it by a set of vacuum ports 209 . Immediately after each measurement, the film strip can be advanced in the direction of the capstan 211 and accumulated in a waste reel (not shown) held in a housing 213 of the droplet measurement system. Note that the depicted system is modular and moved as a unit, for example, to position the measurement window 203 (and the associated measurement area defined by this window) in close proximity to any printhead nozzle to be measured , is a "standard deposition depth" relative to one of the nozzle plates of the print head. In an alternative embodiment, the drop measurement system 201 can be linked in three dimensions such that the system can be placed adjacent to other sets of nozzles and the deposition height can be varied as desired.

FIG. 3 shows an internal cross-sectional view of a droplet measurement system 301 . The system similarly includes a viewing window 303 through which images are captured, and an optical system including an optical assembly 305 , a camera 307 and a light source 309 . Stepper motor 311 selectively advances optical assembly 305 linearly, ie, back and forth in the direction indicated by arrow 313 , relative to viewing window 303 . Note that in this description "camera" can alternatively mean any type of light sensor, i.e. it is possible to use a simple line sensor comprising individual optical sensors, and for example , "swipe" the line sensor back and forth to use the stepping motor 311 to image the entire viewing window 303. In other embodiments, the camera captures images of representative inspections by any conventional mechanism, for example, using a commercial photosensitive camera, charge couple device array, ultraviolet or other non-visible radiation camera, or by other means. An image of a pixel array of the region. Note that camera movement (ie, scanning movement) is not necessary for all embodiments. In the depicted embodiment, optics assembly 305 also internally includes a beam splitter that passes light from the light source (e.g., up to viewing window 303), but uses a beam splitter in the direction of camera 307. The mirror turns the returning (reflected) light. It should be apparent that light from the light source passes through the viewing window, through the transparent film strip, reflects off the print head (not shown in Figure 3), returns through the transparent film strip again, and undergoes any focusing or other optical action, is photographed and processed for analysis. A captured image thus provides a visible indication of the position of each nozzle being measured (e.g., this image was taken as a reflection from the nozzle plate) and also shows the stack of any deposited droplets (which are transparent, but distinguishable from the film). cover. In other words, in the envisaged process (especially for OLED display manufacturing, for example, for an encapsulation layer), the deposited material is translucent and thus does not block the imaging of the nozzle plate. Figure 3 also shows a capstan 315 for transport of the transparent film tape and a UV curing rod 317 for curing any deposited ink to prevent transfer of the deposited ink to any other system components. Figure 3 also shows an interface and control board 319 for the control of various system components, and for the control of image capture; this interface and control board 319 also controls the transport of film strips, for example, by controlling the The film rolling motors 321 and 323 are used for film storage and supply rolls (not shown separately in the figure). Depending on the embodiment, image processing may be performed locally on the interface and control board 319, or, alternatively, in a processor at the manufacturing facility or on a remote computer.

4A and 4B show perspective views of the droplet measurement system 301 of FIG. 3 . Figure 4B represents a perspective view relative to the back side of the unit of Figure 4A, that is, the view from the vantage point provided by arrow B-B of Figure 4A. More specifically, the drawings show viewing window 303, vacuum port 403, UV curing rod 317, a film supply reel 405 and take-up reel 407, and a frame and optical chamber 409 (which houses interface and control panel 319, as previously described). During operation, it supplies unused film tape in the direction indicated by arrow 411 and tightly adheres to viewing window 303, as previously mentioned. From this point, the film is advanced on capstan 315 down arrow 412 towards UV curing rod 317 for the purposes previously described. The operation of the aforementioned UV curing rods is controlled by the interface and control board 319 using on-board firmware or software stored in a non-transitory machine-readable medium. Finally, after curing, the film is advanced to take-up roll 407 substantially as indicated by arrow 415 . It should be apparent that the entire unit is modular, providing ease of removal and maintenance, for example, removal of one of the transparent deposited film strips complete storage reel 407, and replacement of the supply reel 405 with a new feed.

FIG. 5A presents a flowchart associated with an embodiment 501 of a method of performing droplet measurements. As previously mentioned, it may be desirable to perform in-situ measurements, ie, measurements directly within a manufacturing facility, to dynamically update the value of one or more droplet parameters for process, age, temperature, or other factors. For this purpose, it is advantageous to perform measurements in a service station of a printing press, for example, while a new substrate is being loaded, unloaded, cured after deposition, or other periods of inactivity with respect to actual printing. Referring to numeral 503, one or more printheads (eg, loaded into a common printhead assembly) are advanced to the service station and "parked" for servicing actions. This maintenance action may include various calibrations, printhead replacement, nozzle cleaning or other quality treatments, drop measurement as contemplated by the present disclosure, or other uses. As will be described more fully below, for OLED display manufacturing applications (and the manufacture of certain other devices, such as solar panels), it may be desirable to perform printing in a controlled environment; therefore, among many applications In this case, the "parked" location will be in a second controlled environment chamber, for example, in one that can be operated externally (for example, for print head replacement) without having to communicate the entire manufacturing facility or printing press to a In a location in an uncontrolled environment. That is, this second chamber is in preferred embodiments made to have a small size relative to any printing enclosure, for example, occupying two percent or less of the overall printing chamber volume. space to minimize leakage, if any. Once the printhead is parked, it is sealed in this second controlled environment, and the aforementioned droplet measurement system ("DMU", standing for droplet measurement unit) is selectively engaged to perform measurements (505). As noted in optional process block 507, if the printing system is for one of the moving windows of the nozzles (e.g., where different nozzle sets are moved between printing runs as previously mentioned when substrates are loaded or unloaded measurement or re-measurement) is performed on an intermittent basis, the system retrieves an initial address to position the DMU to capture the selected subset of nozzles. Note that this process can use an alignment procedure to identify the corner nozzles of each printhead (eg, updated when a printhead is replaced so that the system is calibrated to "know" the approximate position of each nozzle). This alignment procedure can be performed by linking the above-mentioned DMU (and its camera) for imaging, and thereby finding the corner nozzles of each array, and using an approximate position addressing and search procedure (for example, a spiral search algorithm (spiral search algorithm) )) are performed, for example, as described in previously referenced US Patent Application Serial No. 14/340403. The system's control of positional drop positioning is very precise, e.g., to a precision of about one micron, and typically recalibration of the printhead to drop measurement system positioning is not necessary unless a system component is manually replaced (e.g. , DMU or a printhead is removed or repaired). When a strip of transparent film (i.e., the droplet deposition surface for testing) is positioned, reference numeral 509, the system controls the print head nozzles under inspection to each deposit a controlled number of droplets (quickly and continuously, if each each nozzle is intended to measure multiple droplets). At the same time, the image capture system in the DMU images the deposited ink and the position of the nozzle (for example, captures the light reflected by the printing head through the transparent film strip and ink). Please note that, as indicated by reference numeral 511, in one embodiment, image capture is performed in color to enable identification of the ink concentration in any deposited ink droplets (e.g., when translucent, which will vary depending on material or thickness). imparts a subtle color quality). As indicated by reference numeral 511, a captured image can be filtered (for example, for color, intensity, gamma, or one or more of any other desired parameters) to generate a filtered image; then After this filtering action (or as part of this filtering action), the captured image is converted into gray scale, refer to numeral 513 . Note that multiple images can also be generated from this process according to separate filters, eg a first image representing the nozzle and a second image representing the deposited droplet; obviously there are many permutations. The image processing software then uses the output grayscale image(s) to identify nozzles, ink droplets, positional differences between nozzles and ink droplets, drop volume, drop diameter, drop shape, and/or any Other required parameters (515/517). It should be apparent that it is not necessary to measure all of the items described above in all examples. For example, in a system that calculates drop volume, it may not be necessary to image the nozzle itself, or analyze drop shape or position. Instead, in this embodiment (if the spread of multiple droplets is being analyzed), it is important to determine the magnitude of the deviation in droplet position or to perform color analysis to correctly calculate the volume. The parameters measured will basically depend on the implementation and the desired results. As shown at 517, whatever parameter is measured, the system calculates one or more measurements, or an offset of a parameter, for example, using an optional criterion 519, as previously described. Such an offset or value for a parameter may be calculated for drop or nozzle position, drop timing, or drop volume, or any combination thereof, as indicated by reference numeral 521 . The system then updates a stored information repository located locally or remotely at the DMU ( 523 ), and it then stores the position for the next measurement iteration step and advances the tape, see optional flow 525 . The flow is thus complete, ready for another measurement iteration step (which may be performed immediately, or at a later point in time, eg, following a subsequent round of substrate handling).

Note that the calculation of the parameters and/or any positional offsets may optionally be performed by one or more processors running appropriate software (instructions stored on a processor-readable medium), as noted at reference numerals 529-533. and these processors typically store image data in processor-accessible memory, isolate individual image data for each nozzle, calculate parameters from individual image data, and also store each nozzle parameter for processing device can access memory.

5B and 5C show sample images 551 and 571, respectively. The first of these, image 551, represents a photograph taken from a subset of about 40 nozzles of a printhead. Note how the nozzles are slightly staggered from column to column to provide a choice of tight pitch variations among an intersecting scan axis (e.g., a droplet destined for a particular substrate location can be drawn from either The array of nozzles prints, providing, in some embodiments, a deposition accuracy of better than, ie, less than, twenty microns). Figure 5B represents a color image, which can then optionally be filtered and/or converted to a grayscale format, and is also a grayscale image after this filtering or conversion (because color is not usually used or allowed in patent applications) figure). Note that in this embodiment, the nozzles are not separately imaged or depicted, although they could be in other embodiments. The second image 571 (FIG. 5C) represents the image of FIG. 5B after filtering and gradient processing to identify droplet diameters. In other words, Figure 5C shows white circles corresponding to droplet diameters, with clearly discernible droplet boundaries. Image processing calculates a center of gravity (e.g., by calculating the horizontal and vertical maximum diameters of these "circles" and by taking medial Cartesian coordinate points along each diameter such that each droplet associated with a specific xy Cartesian position). This position can then be compared to the nozzle position to determine offset, and the system recognizes the variation in offset between nozzles for use in print planning. These photographs can also represent droplet volume processing; for example, image processing software can calculate the diameter and/or area and/or associated color of each droplet and compare this to a factory-defined standard or a field-defined standard Compare to calculate size and density, and from this to calculate volume. Almost any desired droplet parameter can be measured in this way.

A specific drop measurement system is described above, and the application to manufacturing and to an industrial manufacturing equipment/printing machine will be described below. In the following description, an exemplary system for performing such printing will be described, more specifically, for the manufacture of solar panels and/or display devices that can be used in electronic devices (eg, smartphones). , smart watch, tablet, computer, television, monitor, or other form of display). The fabrication techniques provided by this disclosure are not limited to this particular scope, and can be applied, for example, to any 3D printing application as well as to a wide variety of other forms of products.

Figure 6A depicts a number of different implementation levels, collectively designated as reference number 601; each of these levels represents one possible independent implementation of the techniques presented herein. First, techniques as described in this disclosure may take the form of instructions stored on a non-transitory machine-readable medium, as represented by figure 603 (e.g., an executable for controlling a computer or a printing press) instructions or software). For example, the disclosed techniques can be implemented as software tuned to cause a manufacturing device (or embedded printer) to measure one or more droplet parameters using the optical measurement techniques disclosed herein. Second, according to computer icon 605, these technologies can also optionally be implemented as part of a computer or network, for example, within a company that designs or manufactures components for sale or use in other products. Third, as exemplified using a storage media graphic 607, the previously described techniques may take the form of a stored printer control command that, for example, when enabled, will cause a printer to operate in a manner that relies on droplet measurement and related planning. One or more stacks in a component are manufactured by means of (eg, scan path planning or nozzle qualification, as described herein). Note that printer commands may be sent directly to a printer, for example, over a LAN or WAN; in this context, the depicted storage media graphics may represent (but are not limited to) internal RAM, or a servo RAM accessible by a computer, portable device, laptop, other form of computer or a printing press, or portable media such as a pen drive. Fourth, as shown by the same manufacturing device icon 609, the techniques described above can be implemented as part of a manufacturing device or machine, or in the form of such a device or machine (e.g., as a droplet measurement system according to the technology disclosed herein , as a method of manufacture, as software for controlling a drop measurement system, etc.) in the form of a printing press inside. It should be noted that the particular depiction of manufacturing device 609 represents an exemplary printer device that will be described below in connection with FIGS. 6B, 7A and 7B. The techniques described above may also be implemented as a complete or partially complete manufactured component or a component of a manufactured component (e.g., manufactured according to a patented process); for example, in FIG. 6A some such components are depicted In the form of an array 611 of semi-finished tablet devices that will be separated and sold for incorporation into end consumer products. The depicted device may have, for example, one or more encapsulation or other laminates fabricated by means of the methods described above. The technology described above can also be implemented in the form of the above-mentioned terminal consumer products, for example, in the form of a portable digital device 613 (eg, such as an electronic tablet device or a smart phone), a TV display screen 615 (eg, an OLED TV ), solar panels 617, or other types of devices.

Figure 6B shows a contemplated multi-chamber fabrication facility 621 that can be used to implement the techniques disclosed herein. In summary, the depicted apparatus 621 includes some general modules or subsystems, including a delivery module 623 , a printing module 625 , and a processing module 627 . Each module maintains a controlled environment, for example, so that printing can be performed in a first controlled environment by the printing module 625, while other processing, for example, other deposition procedures such as an inorganic encapsulation layer deposition Or a curing process (eg, for printed materials) can be performed in a second controlled environment. Apparatus 621 uses one or more mechanical handlers to move a substrate between modules without exposing the substrate to an uncontrolled environment. Within any particular module, it is possible to use other substrate handling systems and/or specific devices and control systems adapted to the processing that the module is intended to perform.

Various embodiments of the delivery module 623 may include an input loadlock 629 (i.e., a chamber that provides buffering between environments while maintaining a controlled environment), a delivery chamber 631 (also having a loader to transport a substrate), and an environmental buffer chamber 633. Within the printing module 625, it is possible to use other substrate handling mechanisms, such as a flotation table for stable support of a substrate during a printing process. Additionally, an xyz transport system, such as a split axis or overhead transport system, may be used for precise positioning of at least one print head relative to the substrate and provide a y-axis transfer system for transport of the substrate through the print module 625 . It is also possible to use multiple inks for printing within the print chamber, e.g. using separate print head assemblies so that, for example, two different types of deposition processes can be performed within a print module located in a controlled environment . Printing module 625 may include a gas hood 635 housing an inkjet printing system, having means for introducing an inert gas environment (e.g., nitrogen), and otherwise controlling the environment for environmental regulation (e.g., temperature and pressure). Gas environment, gas composition and dust particle content.

Various embodiments of a processing module 627 may include, for example, a transport chamber 636; the transport chamber also includes a handler for transporting a substrate. In addition, the processing module may also include an output load lock 637 , a nitrogen stack buffer 639 , and a curing chamber 641 . In some applications, the curing chamber can be used to cure, bake or dry a monomer film into a uniform polymer film; for example, two specifically contemplated procedures include a heating procedure and a UV radiation curing procedure .

In one application, the apparatus 621 is configured for mass production of liquid crystal display screens or OLED display screens, for example, an array comprising, for example, eight screens at a time, on a single large substrate. These screens can be used in televisions and as display screens for other forms of electronic devices. In a second application, the device can be used in much the same way for the mass production of solar panels.

The printing module 625 can be advantageously used in such applications for depositing organic encapsulation stacks that help protect sensitive components of OLED display devices. For example, the depicted apparatus 621 can be loaded with a substrate and can be controlled to move the substrate back and forth between chambers in a manner that is not interrupted by exposure to an uncontrolled environment during the encapsulation process . Substrates may be loaded via the input load lock 629 . A loader located in the transport module 623 may move the substrate from the input loadlock 629 to the print module 625 and, following completion of a printing process, may move the substrate to the processing module 627 for curing. Each of the controlled thickness, pooled encapsulation, or other stack thicknesses can be established to suit any desired application by iterative deposition of subsequent stacks. Also note that the techniques described above are not limited to encapsulation processes or OLED fabrication and can use many different types of tools. For example, the configuration of device 621 can be changed to place the various modules 623, 625, and 627 in different parallel positions; moreover, it can also use more, fewer or different modules.

While Figure 6B provides one example of a set of linked chambers or fabrication components, many other possibilities clearly exist. The techniques described above can be used with the apparatus depicted in Figure 6B, or even to control a process performed by any other type of deposition apparatus.

Figures 7A-7C are used to generally introduce the techniques and structures used for nozzle-by-nozzle droplet measurement and verification.

More specifically, FIG. 7A provides an exemplary view depicting a drop measurement system 701 and a relatively large printhead assembly 703; the printhead assembly has multiple printheads (705A/705B), each with a plurality of individual nozzles ( For example, 707), where there are thousands or hundreds of nozzles. An ink supply (not shown) is fluidly connected to each nozzle (e.g., nozzle 707), and a piezoelectric sensor (also not shown) is used under the control of a nozzle-by-nozzle motorized control signal. Jet ink droplets. The design of the nozzles maintains a slightly negative ink pressure at each nozzle (e.g., nozzle 707) to avoid flooding of the nozzle plate, where an electrical signal from a particular nozzle is used to activate the corresponding piezoelectric sensor, which A particular nozzle is pressurized and thereby ejects a droplet from that particular nozzle. In one embodiment, the control signal for each nozzle is normally at zero volts, so that a positive pulse or signal level at a particular voltage for a particular nozzle ejects droplets from that nozzle ( one drop per pulse); in another embodiment, different tailored pulses (or other more complex waveforms) can be used between nozzles. However, in conjunction with the example provided in FIG. 7A , it should be assumed that it needs to measure a droplet volume produced by a particular nozzle or set of nozzles (e.g., nozzle 707) where a droplet is deposited from a printhead toward a carrier. A casing 709 of film is ejected downward (ie, in the direction "h" representing the height of the z-axis relative to a three-dimensional coordinate system 708). As mentioned earlier, for embodiments using existing droplet deposition from many nozzles, a target surface is advantageously fixed at a known position relative to the printhead (e.g., so that it knows which deposited droplets belong to which nozzle). The size of the above "h" is usually on the order of one millimeter or less, and within an operating printing press there are thousands of nozzles (for example, 10,000 nozzles) whose individual droplets are individually measured in this way. nozzles) in which the deposition surface is incrementally changed or advanced to multiple windows where many droplets (eg, tens to hundreds) are to be imaged and measured simultaneously. Therefore, in order to accurately measure drops optically from each nozzle, it uses certain techniques in the disclosed embodiments to properly position the drop measurement system 701, the printhead assembly 703, or both relative to each other. Components for optical measurements.

In one embodiment, these techniques use a combination of: (a) x-y translation of at least part of the optical system (711A) (e.g., within dimensional plane 713) to precisely position a measurement region 715, which The measurement region 715 is provided by the system in close proximity to any nozzle or set of nozzles that produced the droplet for optical calibration/measurement, and (b) an in-plane optical return (711B) (e.g., allowing Easy deployment of the measurement area, even under a large print head surface area). Thus, in an exemplary environment having approximately 10,000 or more printing nozzles, the movement system is capable of moving between, for example, 10,000 or so discrete locations near the discharge path of each individual nozzle in the printhead assembly. , positioning at least part of the optical system. Optics are typically adjusted to be positioned such that precise focus is maintained over the measurement area to image deposited droplets on a transparent film or other deposition medium, as previously described. Note that the diameter of a typical droplet can be on the order of microns, so optical placement is often quite delicate and challenging in terms of relative positioning of the printhead assembly and measurement optics/measurement area. In some embodiments, to assist in this positioning, optics (mirrors, mirrors, etc.) are used to adjust the orientation of a light capture path for sensing below the dimension plane 713 originating from the measurement region 715 , so that the measurement optics can be placed close to the measurement region without interfering with the relative positioning between the optics and the print head. This enables efficient positional control in a manner that is not limited by the mm-scale deposition height h of each droplet deposited and imaged, or by a large dimension x and y width occupied by the inspection print head. Alternatively, different beams incident from different angles can be used to image a film or deposition surface from below, or it can also use a coaxial imaging system with a beam splitter. It can also use other optical measurement techniques. In an optional feature of such systems, the movement system 711A is optionally and advantageously fabricated as an xyz transport system which allows the drop measurement system to selectively move without moving the printhead assembly during drop measurement. Engagement and detachment. Briefly, the idea is that in an industrial manufacturing setup with one or more large printhead assemblies, each printhead assembly would be "parked" from time to time in order to maximize production uptime. A service station to perform one or more service functions; given the sheer scale of printheads and nozzle counts, it may be desirable to perform multiple service functions at once on different components of the printhead. To this end, in this embodiment, it may be advantageous to move the measuring/calibration device around the printhead instead of moving the printhead around the devices. [This thus also allows the addition of other non-optical inspection procedures, eg for other nozzles, if necessary. ] In order to facilitate these actions, the printhead assembly can be selectively "parked" as previously described in conjunction with the system to designate a specific group or range of nozzles that are intended to be the subject of optical alignment. Once the printhead assembly or a particular printhead is stationary, a movement system 711A is added to move at least part of the optical system relative to the "parked" printhead assembly and precisely position the measurement region 715 at a location suitable for detecting The position of the droplets ejected from a group of individual nozzles; using a z-axis movement makes it possible to selectively engage the light recovery optics from well below the printhead plane, alternatively or additionally to facilitate optical alignment other maintenance actions. Or in other words, the use of an xyz movement system allows the selective engagement of the droplet measurement system independently of other tests or test devices used in a service station environment. For example, in such a system, one or more printheads in a printhead assembly can also be selectively replaced while the printheads are parked. Note that this configuration is not necessary for all embodiments; other alternatives are possible, such as where only the printhead assembly moves (or one of the printheads moves) while the measurement assembly is stationary, or where there is no need to park the printhead Components.

In summary, the optics used for droplet measurement will include a light source 717, an optional set of light delivery optics 719 (which direct light from the light source 717 to the measurement area 715 as desired), one or more light sources A sensor 721 , and a set of return optics 723 that direct the light used to measure the drop(s) from the measurement region 715 to the one or more light sensors 721 . The movement system 711A selectively moves any one or more of these elements together with the housing 709 (e.g., with the imaging region) in a manner that enables post-drop measurement light to be directed from the measurement region 715 to a location below a plane. ). In one embodiment, light delivery optics 719 and/or light return optics 723 use mirrors that are steered back and forth between measurement regions 715 along a vertical dimension parallel to the direction of droplet travel. The light, and the movement system that moves each element 709, 717, 719, 721 and 723 become an integrated system during drop measurement; As noted at 711C, light delivery optics are also optionally used to supply source light from a location below the dimensional plane 713 of the measurement region, e.g., with light source 717 and light sensor(s) 721 Both direct/collect light from below the measurement area, generally as illustrated. As noted at 725 and 727, the optical system may optionally include lenses for focusing purposes, and photodetectors (eg, for non-imaging techniques that do not rely on processing a multi-pixel "image"). Note also that the selective use of z-move control for the chassis at any point during which the printhead assembly is "parked" allows the optical system to selectively engage and disengage and enable measurement of the area near any group of nozzles The precise positioning of 715. Such parking of the printhead assembly 703 and xyz movement of the optical system 701 is not necessary for all embodiments. Other permutations and combinations are also possible.

Figure 7B provides a flow chart of a procedure associated with droplet measurement in some embodiments. This program flow is generally indicated as reference numeral 731 in FIG. 7B. More specifically, as indicated by reference numeral 733, in this particular procedure, the printhead assembly is first parked, for example, at a maintenance station (not shown) of a printing press or deposition equipment. middle. A drop measurement device then engages (735) the printhead assembly, for example, by selective engagement of part or all of a drop measurement system by moving from below a deposition plane into a drop measurement system An optical system is capable of simultaneously measuring the position of droplets from many nozzles. Referring to numeral 737, this movement of one or more optical system components relative to a parked printhead can be selectively performed in the x, y and z dimensions.

As described in the patent applications incorporated herein by reference in the priority claims, even a single nozzle and associated nozzle firing drive waveform (i.e., the pulse(s) or signal level to eject a droplet) ) can also produce droplet volumes, trajectories, and velocities that vary slightly from droplet to droplet. In accordance with the teachings herein, in one embodiment, the aforementioned droplet measurement system, shown generally at 739, selectively takes n measurements per droplet of a desired parameter to derive a desired property of that parameter. Statistical reliability. In one embodiment, the measured parameter may be volume, but for other embodiments, the measured parameter may be flight speed, flight trajectory, nozzle position error (eg, nozzle warpage), or other parameters, or a plurality of A combination of one of these parameters. In one embodiment, "n" may vary per nozzle, but in another embodiment, "n" may be a fixed number of measurements each nozzle is scheduled to perform (e.g., "24"); In yet another embodiment, "n" represents a minimum number of measurements such that more measurements can be performed to dynamically adjust the measurement statistics of the parameter or to increase confidence. Obviously, many variations are possible. With the previously described system, a measurement population can be established immediately (i.e., by taking multiple droplet measurements for a particular nozzle array during a single measurement iteration step, in other words, without moving the droplet measurement system to a different nozzle sets), or by taking a single measurement and building up a measurement total from later measurements (for example, when measurements are taken continuously over time through a circular range of nozzles).

For the example provided in Figure 7B, it should be assumed that drop volume is being measured to obtain an accurate average representing the expected drop volume from a particular nozzle and a tight confidence interval. This facilitates selective programming of droplet combinations (using multiple nozzles and/or drive waveforms) while reliably maintaining the distribution of mixed ink fill (i.e., relative to the droplet mean) in a target area near a desired target. the mix). As noted in optional process blocks 741 and 743, the contemplated optical measurement process ideally facilitates the one-time, real-time or near-real-time measurement and calculation of the volume (or other desired parameter) of many nozzles, for example, using a transparent film and the capture below the deposition plane (that is, from the opposite side of the film used for deposition); with this fast measurement, it becomes possible to frequently and dynamically update volume measurements, for example, to compensate for ink properties (including viscosity and constituent materials) , temperature, nozzle clogging or aging, and other factors change over time. Based on this, for example, in the case of a printhead assembly containing 10,000 nozzles, it is expected that the huge total number of measurements for each of these thousands of nozzles can be obtained in a few minutes, so that it can be performed frequently and dynamically Droplet measurement. As mentioned earlier, in an alternative embodiment, droplet measurement (or measurement of other parameters such as trajectory and/or velocity) may be performed as a periodic intermittent procedure, either on a schedule or between substrates Droplet measurement system placed in between (e.g., while substrates are being loaded or unloaded), or stacked under other components and/or other printhead servicing procedures to efficiently collect many data points over many measurement intervals points (and thereby establish a statistical distribution representing each nozzle). Note that this rapid measurement system facilitates scan path adjustments, nozzle pass/fail verification, and generation of various nozzle waveform pairs for embodiments that allow the use of alternate nozzle drive waveforms in a per-nozzle specific manner. The programmatic droplet combination of the droplets of , as briefly mentioned in the patent application incorporated herein by reference in the content of the previous text and the priority statement. Referring to numerals 745 and 747, by measuring the expected droplet volume to an accuracy better than 0.01 pL, it becomes possible to plan very precise droplet usage, where droplet usage can also be planned (in ideal case) to 0.01 pL resolution, and wherein the measurement error in one embodiment is effectively reduced to provide 3σ (or other statistical values such as 4σ , 5σ , 6σ , etc.) credibility. The same holds true for drop position and/or velocity and/or nozzle warp. For example, it becomes possible to provide very precise deposition by measuring the expected position to an accuracy better than one micron (or another distance magnitude); the expected position can be measured to a specific Cartesian point and standard within a certain range of the difference (or, for example, 4σ , 5σ , 6σ distances around this point). Once sufficient measurements have been made for the various drops, the fill involving combinations of the drops can be evaluated and used to plan printing in the most efficient way possible (748). As indicated by divider line 749, the performance of droplet measurements may be switched intermittently back and forth between the current "online" printing procedure and the "offline" measurement and calibration procedure; note that in order to minimize manufacturing system downtime, these Measurements are typically performed when the printing press is dispatched to other processes, such as during substrate loading and unloading. Referring to numeral 751, in one embodiment, the transparent film or film strip can be specifically selected (or treated) to optimize the droplet properties (i.e., the specific chemical or fluid properties of the ink) of the particular ink being analyzed. ) for the purpose of assisting image capture and/or analysis. For example, in some applications, the ink system will later be cured by a UV light curing process to convert a monomer (monomer) into a polymer; Can be selected to have physical, color, absorbing, immobilizing, curing, or other properties that enhance the predictability of analyzing the material with imaging systems. Finally, referring to numeral 753, the film (strip) or droplet measurement system as a whole (or both) can be designed for modular replacement to minimize measurement system and printing system downtime.

During printing, nozzle (and nozzle waveform) measurements can be made on a rolling basis, advancing through a range of nozzles, with each break occurring between substrate printing actions. Whether engaged to re-measure all nozzles or not, or on such a rolling basis, the same basic procedure of FIG. 7B can be used to take measurements. To this end, when the droplet measurement device is added for a new measurement (either immediately after a previous measurement or immediately after a substrate printing operation), the system software loads a pointer to the next measurement for which it is scheduled to be measured. Nozzle set (eg, for a second printhead, "nozzle window at nozzle 2,312 in the upper left corner"). In the case of an initial measurement (e.g., in response to a new printhead installation, or a recent start-up, or a periodic procedure such as a daily measurement procedure), the above pointer will point to a first nozzle of a printhead , for example, "Nozzle 2,001". The nozzle is associated with a particular imaging grid accessed or looked up from memory. The system uses the provided address to advance the droplet measurement system (eg, the previously described measurement zone) to a position corresponding to the desired nozzle location. Note that in a typical system, the mechanical throw positioning associated with this movement is quite precise, ie, to a resolution of about a micron. At this point the system selectively searches for nozzle positions near the expected micron resolution position, and finds the nozzle and its positional center based on the image analysis of the print head within a micron distance from the estimated grid position. For example, a zigzag, spiral, or other search pattern may be used to search for the desired location for a nozzle or fiducial that has a specific positional relationship with respect to the desired set. A typical pitch distance between nozzles may be on the order of 250 microns, while nozzle diameters may be on the order of 10 to 20 microns.

Figure 7C provides a flowchart for nozzle qualification. In one embodiment, droplet measurements are performed to generate statistical models for any and/or each of droplet volume, velocity, and trajectory for each nozzle and each waveform applicable to any particular nozzle (e.g. distribution profile vs mean). Thus, for example, if there is a choice of two waveforms for twelve nozzles, there are up to 24 waveform-nozzle combinations or pairings; in one embodiment, for each nozzle or waveform-nozzle pairing The number of measurements taken for each parameter (eg, volume) is sufficient to develop a robust statistical model. Note that despite planning, it is conceptually possible for a particular nozzle or nozzle-waveform pairing to produce an anomalously broad distribution, or an average that is so off track that it should be treated specially. This applied special process is conceptually depicted in Figure 7C in one embodiment.

More specifically, it uses reference number 781 to denote a method generally. The data generated by the droplet measuring device is stored in the memory 785 for later use. During the application method 781, this data is recalled from memory, and the data for each nozzle or nozzle-waveform pair is extracted and processed individually (783). In one embodiment, it establishes a normal random distribution for each variable subject to qualification, defined by a mean, standard deviation, and number (n) of measured droplets, or equivalent quantities. Note that other distribution formats can be used (eg, Student's-T, Poisson, etc.). The measured parameters are compared (787) to one or more ranges to determine whether the associated droplet can actually be used. In one embodiment, at least one range is applied to disqualify the droplet from being used (e.g., the nozzle or nozzle-waveform pairing may be excluded if the droplet has a volume that is too large or too small for the desired target short-term use). To provide an example, if 10.00 pL droplets are required, nozzles or nozzle-waveform pairs tied to droplet averages above this target, e.g., 1.5% (e.g., <9.85 pL or >10.15 pL), can be excluded from use. It may also or instead use range, standard deviation, variance, or other measures of separation. For example, if a statistical model of droplets with a narrow square distribution is desired (eg, 3σ < 1.005% of mean), then droplets whose measurements do not meet this criterion can be excluded. It is also possible to use a sophisticated/complex set of criteria that takes into account multiple factors. For example, an unusual mean combined with a very narrow separation may be acceptable, e.g., if the separation (e.g., 3 σ) is within 1.005% of the measured (e.g., abnormal) mean µ, then use a related droplet. For example, if it is desired to use droplets with a 3 σ volume within 10.00 pL ± 0.1 pL, one can rule out producing a nozzle-waveform pair with a 9.96 pL average of a 3 σ value of ± 0.8 pL, but produce A nozzle-waveform pairing with a ±0.3 pL 3 σ value of 9.93 pL average would probably be acceptable. Clearly, there are many possibilities depending on any desired rejection/exception criteria (789). Note that this same type of treatment can be applied to the flight angles and velocities of each droplet, i.e., it is expected that the flight angles and velocities of each nozzle-waveform pair exhibit a statistical distribution and depend on the For measurements and statistical models of the device, some droplets can be excluded. For example, a droplet whose mean velocity or flight trajectory deviates by more than 5% from normal, or whose velocity variation is outside a specified target, can be presumed to be excluded from use. Different ranges and/or evaluation criteria may apply to each droplet parameter 785 measured and provided by the memory.

Note that depending on the rejection/exception criteria 789, droplets (and nozzle-waveform combinations) may be handled and treated differently. For example, it may reject a particular droplet (791) that does not meet a desired criterion, as previously described. Alternatively, it is possible to selectively perform more measurements for the next measurement iteration step of a particular nozzle-waveform pair; for example, if a statistical distribution is too broad, it may be specific to that particular nozzle-waveform pairing Perform more measurements to improve the tightness of this statistical distribution with more measurements (for example, the variance and standard deviation depend on the number of data points measured). Reference numeral 793, it is also possible to adjust a nozzle drive waveform, e.g., use a higher or lower voltage level (e.g., to provide greater or lesser velocity or a more consistent flight angle), or reshape A waveform is adjusted to generate a nozzle-waveform pair that meets one of the specified criteria. Referring to numeral 794, the timing of the waveforms may also be adjusted (eg, to compensate for abnormal mean velocities associated with a particular nozzle-waveform pairing). For example (mentioned earlier), a slow droplet can be fired at an earlier point in time relative to other nozzles, while a fast droplet can be fired slower in time to compensate for the faster flight time . Many such alternatives are possible. Finally, referring to numeral 795, any adjusted parameters (e.g., shot time, waveform voltage level or shape) can be stored and, optionally, the adjusted parameters can be applied for re-measurement, if desired. One or more associated droplets. After each nozzle-waveform pair (modified or otherwise processed) is qualified (passed or failed), the method then proceeds to the next nozzle-waveform pair, reference numeral 797 .

The aforementioned mechanism can also be used to measure nozzle warpage (and of course verify nozzle qualification on this basis). In other words, if it is assumed, for example, that a population of deposited droplets originates from a single common precise nozzle location, but is clustered off-centre in a direction orthogonal to the scanning movement of the printhead substrate, the nozzles in question may be relatively located relative to Nozzles on a column or row are offset. Such anomalous offsets may lead to deviations from idealized droplet ejection, which can be taken into account when planning the precise combination of droplets, in other words, any such "warping" or individual nozzle offsets are stored and used to Validating nozzle pass/fail or as part of print scan planning, as previously described, allows the printing system to use the variance of each individual nozzle in a planned manner rather than attempting to smooth out the variance using averaging . In an optional variation, the same technique can be used to determine irregular nozzle spacing along the printhead scan direction (i.e., the fast printing axis), although for the depicted embodiments, any such Errors are attributed to corrections for droplet velocity deviations (e.g., any such spacing errors can be adjusted by corrections to nozzle velocity, e.g., due to a small change in the drive waveform for that particular nozzle By). To determine the cross-scan axis warp of a nozzle producing a cluster of droplets, the individual trajectories are actually inversely plotted (or otherwise applied with a mathematical transformation) relative to other measured trajectories for the same nozzle and used to identify the observed The average cross-scan axis position of one of the specific nozzles. This position may deviate from an expected position for such a nozzle, which may be evidence of nozzle warping.

As previously stated and as implied by this description, an embodiment establishes a statistical distribution for each nozzle for each measured parameter, e.g., for volume, velocity, trajectory, nozzle warp, and possibly other parameters . As part of these statistical procedures, individual measurements can be discarded or used to identify errors. To give some examples, if a drop measurement is found to have a value that has been removed from other measurements of the same nozzle so far, the measurement may represent a shot or measurement error; in one embodiment, if the deviation To a point where a statistical error parameter is exceeded, the system discards the measurement. If no droplets are seen at all, this may be evidence that the droplet measurement system is on the wrong nozzle (wrong position), either having a firing waveform error or a nozzle under inspection failing. It can use an error handling procedure to make appropriate adjustments, including taking any new or further measurements as needed.

Note that although Figures 7A-7C are not individually invoked, they essentially perform the depicted measurement procedure for each of the available candidate waveforms used with each nozzle. For example, if each nozzle has four different piezoelectric drive waveforms to choose from, the measurement procedure may typically be repeated 4 times for each group of nozzles; If the 24 droplets of the waveform establish a statistical distribution, a nozzle can have 96 such measurements (24 for each of the four waveforms), where each measurement is used to obtain each of the droplet velocity, trajectory, and volume. One, and statistical mean and distance measurements for estimating nozzle position (eg, for assessing nozzle warpage). In a contemplated embodiment, any number of waveforms may be shaped or otherwise generated, and the system measures droplet parameters associated with one or more preselected waveforms and thereby stores these parameters for subsequent use in printing and / or print planning. These parameters can also be used to decide whether to maintain (and store) a waveform for use in printing (for example, as part of a preselected set of allowed waveforms), or to select a different waveform and measure multiples of that waveform. parameter.

Through the use of precise mechanical systems and droplet measurement techniques, the disclosed method allows extremely high accuracy measurements of individual nozzle characteristics, including the average of each of the aforementioned parameters (e.g., volume, velocity, trajectory, nozzle position, and others). Droplet measurement. It should be appreciated that the described techniques facilitate a high degree of uniformity in processes, especially for OLED devices, and thus enhance reliability. The teachings presented above help provide a more efficient solution by providing control efficiencies, particularly with regard to the speed of droplet measurements, and stacking these measurements with other system processes in a manner calculated to reduce overall system downtime. A fast and less expensive process designed to provide flexibility and precision in the manufacturing process.

Figure 8A shows a cross-sectional view 801 of a typical arrangement within an industrial manufacturing facility (eg, associated with a printing press in such a facility). More specifically, it can be seen that printing is performed within a printing closed chamber 803 so that the surrounding environment can be controlled ("controlled environment"); this control is usually performed to exclude unacceptable dust particles, Alternatively, printing is performed in the presence of a particular gas composition (eg, nitrogen, noble gases, etc.). In summary, a substrate 813 is generally introduced into the printer using an environmental buffer chamber (not shown) and transported to a floating support 815 using a mechanical handler, which is also passed through one or more Detection of fiducials (such fiducials and a camera or other optical detector not shown in FIG. 8A to detect precise substrate position) properly aligns the substrate for printing. Printing is performed using a printhead assembly 807 that traverses along a traveler 811 in the direction of a "slow print axis" (as depicted by arrow 809). Printhead assembly 807 is depicted as a single item, but it could be a complex assembly carrying multiple printheads (e.g., 6, 10, or other numbers), each with hundreds to thousands of printing nozzles (e.g., 2,000 nozzles each). The printhead assembly 807 spots a liquid ink to a precise thickness at precise locations on the substrate 813, where the ink comprises a material that will form a permanent stack of one or more products intended to be fabricated on the substrate 813 . For example, such a material may be an organic or inorganic material, a conductor or insulator, a plastic, a metal, or some other type of material. In a typical application, the substrate 813 is more than one meter wide and several meters long and is used to simultaneously manufacture multiple OLED displays arranged in an array on the substrate; each stack is deposited across all such "substrates." panel" (that is, across multiple such displays in manufacture) as part of an integrated printing process in which the individual displays are finally cut from the substrate by other processes. Each printing process can deposit a different ink to a specific thickness, for example, conductors, insulators, light emitting elements, semiconductor materials, encapsulation, etc., using printing instructions specific to the particular stack. In an assembly line process, there may be multiple printers, configured at different locations or used in successive different deposition processes. For OLED materials, an ink is deposited for a particular stack, and after deposition, the substrate is removed from the chamber and advanced into a curing chamber (not shown), where the deposited ink can be cured, dried , heated, or otherwise treated to impart durability to the deposited material. Note that the configuration depicted represents a "split-axis" printing press, that is, the floating table 815 and associated loader (not shown) is seen along one of the dimensions referenced 823 near the lower right corner of the figure. In the direction of the Y-axis 825, the substrate is pushed into and out of the drawing page.

To perform drop measurement, the printhead assembly 807 is selectively advanced outside of a normal printing area to a point where it can be parked in a maintenance station, generally associated with a second Closed environment 805. This second environment is optional, but advantageous to allow inspection, print head replacement, and other forms of maintenance without adding vents to the print enclosure 803 . To park the printhead assembly 807, the assembly is moved to a position that appears to be generally on the left side of the figure, and then advanced vertically to seal the printhead assembly 807 in a chamber that acts as the second closed environment , as depicted by dotted line position 819. In this "parked" position, the droplet measurement system 817 can be controlled (eg, in three dimensions) to selectively move a measurement region, simulating a substrate deposition height adjacent to any desired nozzle region.

Note that, as previously mentioned, in a typical application it is desirable to keep the manufacturing facility 801 "on-line" and in use as much as possible. To this end, instead of performing drop measurement when the apparatus 801 can be used for printing (but for product manufacturing), in one embodiment, measurement and printing are "ping-pong alternated", that is, every Each time a substrate (e.g., 813) is loaded or unloaded, the printhead assembly 807 is advanced to a service station and locally calibrated (e.g., for print nozzles and/or print nozzles A rolling subset of the waveforms) to build a robust set of measurements for each nozzle in a manner that accumulates a statistical measurement total, updated to the latest state, and serviced, as previously described. Note that any of these features may be considered optional, and not all are necessary for the disclosed technology to work.

Figure 8B provides a plan view of what the substrate and printer might appear during the deposition process, taken along line B-B of Figure 8A. The printing enclosure is likewise generally indicated by reference numeral 803 , while a second enclosure for droplet measurement is generally indicated by reference numeral 805 . Within the printing enclosure, the substrate to be printed on is also generally indicated by reference numeral 813 , while the support table for transporting the substrate is generally indicated by reference numeral 815 . In general, any xy coordinate of the substrate is reached by a combination of movements, including movement of the substrate in the x and y dimensions by the support table (e.g., using a floating support, as indicated by reference numeral 857), and using Movement in the "slow axis" x-dimension of one or more print heads 807 of slide bar 811, as generally indicated by arrow 809. As previously mentioned, floating stages and substrate handling infrastructure are used to move substrates along one or more "fast axes" during printing as needed. It can be seen that the printhead has a plurality of nozzles 865 each controlled by a spray pattern directed from a printed image (e.g. when the printhead goes from left to right and from right to move to the left, incurring the printing of rows corresponding to the printing press's grid points); note that while only a few printing nozzles are depicted in the figure, they actually contain hundreds to thousands of such nozzles, configured as Many rows and columns. With relative movement between the one or more print heads and the substrate provided in the direction of the fast axis (ie, the y-axis), printing essentially appears to follow a swath of individual columns of printer grid points. It may also selectively rotate or otherwise adjust the printhead assembly to alter the effective nozzle spacing, reference numeral 867 . Note that multiple such printheads can be used together, with offsets in the x-, y-, and/or z-dimensions relative to each other adjusted as desired (see illustration of axes in FIG. 8B). The printing action continues until the entire target area (and any border areas) have been printed with ink as desired, where the vertical component of the depicted transfer direction 857 represents relative printhead assembly/substrate movement. After the deposition of the necessary ink volume, the substrate is finished, such as by using an ultraviolet (UV) or other curing or hardening process to form a permanent laminate from the liquid ink. As described earlier, when substrates are loaded or unloaded for printing, the printheads are advanced to a service station and sealed to a second closed environment 805 . Practically, this second enclosure is configured as a subset of the printing enclosure 803 as previously described, so that it is possible to replace a print head without adding ventilation holes to the printing enclosure at all. Within the second enclosed environment 805, the droplet measurement system 817 (seen in dashed lines below the slide bar 811) is selectively engaged (again, advantageously utilizing the entirety of the droplet measurement system, such as one of the enclosures) Sexual three-dimensional linkage) for measurement as described earlier.

Figure 9 provides a graph illustrating the measured drop position relative to the drop's expected position for each of a number of nozzles. More specifically, the diagram is indicated generally by reference numeral 901 and shows a cluster of approximately 40 nozzles. It should be assumed that graph 901 represents image data, for example, processed as previously described with reference to FIGS. 6A to 6C to obtain a measured droplet position (i.e. That is, such as location 903). With respect to Figure 9, some features should be noted. First, the nozzles appear to be configured as slightly staggered columns of nozzles in position, as shown by icon 905; this feature allows for extremely precise droplet spacing, for example, when manufacturing tolerances cause nozzles to be positioned a span of several hundred microns apart. Slight staggering between columns in the scan direction allows for the use of alternating nozzles (e.g., nozzles corresponding to position 906 relative to nozzles corresponding to position 907), which allows for extremely tight droplet placement, e.g., at Within 20 microns or less of any predetermined location on a substrate. Second, diagram 901 indirectly emphasizes the benefits provided by calibration of the drop measurement system relative to a printhead position, e.g., it is important for the system to know exactly which nozzle corresponds to position 903 and the expected position 904, as shown in Ability to match any measurement data (and any nozzle qualification or adjustment) to the correct nozzle. Through image processing, it is possible to determine the precise positional offset of each nozzle, which is factored into nozzle qualification verification and printing planning. Finally, note again that the use of a transparent film allows imaging not only of deposited droplets, but also of nozzles (eg, through the transparent film), which facilitates the performance of distance analysis by the software. This is not necessary for all embodiments. For example, through the understanding of how the photographed image of the film corresponds to the position of the nozzle plate, the software can easily infer the position of the nozzle relative to the photographed image, and calculate the position offset based on this . In the context of FIG. 9 , reference numeral 904 represents image nozzle position in one embodiment, where any deviation between measured position 903 and position 904 represents drop velocity and/or warpage. Also, while FIG. 9 represents drop position offset relative to expected drop position, a similar analysis can be used to measure drop volume, for example, by dividing drop color (e.g., gray scale values ), drop diameter, or other characteristic of the captured image is compared to a standard from which the drop volume is calculated. Through the use of iterative additional measurements per nozzle or nozzle-waveform pairing, the system can easily establish the distribution of any desired droplet parameter on a per-nozzle or per-nozzle waveform basis.

FIG. 10 shows a flowchart 1001 associated with determining droplet volume from a captured image. Referring to numeral 1003, a captured image representing droplets generated by a nozzle array is first retrieved from the memory. This image is then optionally filtered to precisely segment the droplets of interest (eg, with different color intensities depending on ink thickness or concentration on the deposition medium), see numeral 1005 . Note that these filtered images may be the first, second, third, or other samples of one of the filtering actions performed to measure a specific parameter from a single image (e.g., other samples may be used for droplet velocity , position, nozzle position, etc. to calculate distance, position, offset, etc.). Referring to numeral 1007, any color hue is then processed to correlate that hue to ink thickness or density; for example, if the deposited ink has a slightly reddish tint, a "redder" portion of the image will generally represent a greater thickness . Note that for embodiments where multiple droplets are deposited at once from each nozzle, there may be multiple visible droplet overlaps, and thickness processing 1007 takes this into account in the preferred implementation, segmenting However, this is not necessary for all embodiments, for example, if it is known that, say, five droplets have been deposited, it may be sufficient to calculate the overall volume and divide by five. Referring to numeral 1009, the droplet radius is then calculated (or pooled ink coverage) as described earlier and used in conjunction with the derived thickness measure to calculate the total deposited ink. Importantly, the transparent film used as a deposition surface ideally holds the deposited ink and thus may differ from an actual deposition surface (e.g., a glass substrate) used in actual printing; therefore, as indicated by reference numeral 1008 As depicted, one of the stored criteria specific to the deposited material is retrieved and used in conjunction with thickness processing, volume calculation 1011 , or both, to derive the correct drop volume estimate. Finally, the measurement data is stored, reference numeral 1013, and any calculated per-nozzle or distribution of per-nozzle waveforms (eg, mean and separation) are updated for use in printing or scanning planning. Note that similar comparisons calculated for a standard and raw value (or offset) can be applied to many other parameters besides volume, depending on suitability for a particular application.

Appreciated from the above-mentioned various technologies and considerations, a process can be implemented to mass-produce products quickly and with low system cost. By providing fast repeatable printing techniques, it is believed that printing can be substantially improved, for example, reducing layer-by-layer printing times to a fraction of the time required without the aforementioned techniques. Returning again to the example of large HD television displays, it is believed that for large substrates (e.g., Gen 8.5 substrates, approximately 220cm x 250cm), each color component stack can be printed accurately and reliably, within 180 seconds or Less time, or even ninety seconds or less, represents a substantial process improvement. Improving printing efficiency and quality paves the way for dramatic cost reductions in the production of large HD TV displays, resulting in lower end-consumer costs. As previously mentioned, display manufacturing, particularly OLED manufacturing, is one application of the techniques described here, which can be applied to a wide variety of processes, computers, printing presses, software, manufacturing equipment, and end-devices. Limited to the display panel.

In the foregoing description and accompanying drawings, specific terms and figure symbols were used to provide a thorough understanding of the disclosed embodiments. In some instances, the terms and symbols may imply specific details that are not necessary to put the embodiments into practice. The terms "exemplary" and "embodiment" are used to indicate an example, not a preference or requirement.

As previously indicated, various modifications and changes may be made to the embodiments presented herein without departing from the broader spirit and scope of the disclosure. For example, any feature or characteristic of any embodiment can be combined with any other embodiment, at least where practicable, or can replace its equivalent feature or characteristic. Thus, for example, not all features may be shown in each drawing, eg, a feature or technique shown in accordance with an embodiment of a drawing should be assumed to be selectively employable as an alternative to any other drawing. One of the elements in the formula or embodiment, or a combination thereof, even if not specifically indicated in the specification. Accordingly, the specification and drawings should be interpreted in an illustrative rather than restrictive sense.

101: Flowchart 103-123: Steps 201: Droplet measurement system 203: Measurement window 205: Arrow 207: roll 209: Vacuum port 211: Winch 213: Chassis 301: Droplet measurement system 303: View window 305: Optical components 307: camera 309: light source 311: stepper motor 313: direction arrow 315: Winch 317: UV curing rod 319:Interface and Control Panel 321: film scrolling motor 323: film scroll motor 403: vacuum port 405: film tape supply reel 407: Membrane storage reel 409:Frame and Optical Chamber 411: direction arrow 412: direction arrow 415: direction arrow 501: Method for performing droplet measurement 503-533: Steps and Related Items 551: sample image 571:Sample Image 601: Different implementation classes 603: Non-transitory machine-readable media 605: computer 607: storage media 609: Manufacturing device 611: semi-finished flat panel device array 613: Portable digital devices 615: TV display screen 617: Solar panel 621: Multi-chamber manufacturing equipment 623:Transportation module 625: Printing module 627: Processing module 629: Input load lock 631: transport chamber 633: Environmental buffer chamber 635: gas mask 636: transport chamber 637:Output load lockout 639: Nitrogen stack buffer 641: curing chamber 701: Droplet measurement system 703:Print head assembly 705A: print head 705B: print head 707: Nozzle 708: Three-dimensional coordinate system 709: Chassis 711A: Mobile Systems 711B: Under-plane optical recovery 711C: Light source supply under the plane 713: Dimension plane 715: Measurement area 717: light source 719: Light delivery optics 721: Light sensor 723: Reverting Optics 725: focus lens 727:Non-imaging device 731: Droplet measurement process 733-753: Steps and Related Items 781: method 783-797: Steps and Related Items 801: Typical configuration in industrial manufacturing equipment 803: Printing closed chamber 805:Second closed environment 807:Print head assembly 809:arrow 811: sliding bar 813: Substrate 815: floating table 817: Droplet measurement system 819: parking position 821:Arrow 823: dimension reference 825:Y axis 857: Transfer direction 865:Nozzle 867:Nozzle spacing 901:Charts 1001: Flowchart 1003-1013: Steps and Related Items

[FIG. 1] is a flowchart illustrating a technique for measuring a parameter of a droplet. [Fig. 2] A close-up perspective view of one of the droplet measurement systems. [ Fig. 3 ] A sectional view of a droplet measuring system. [FIG. 4A] is another perspective view of a droplet measurement system. [ FIG. 4B ] is a perspective view of the 4A droplet measuring system taken from the commanding height of the arrow B-B in FIG. 4A . [FIG. 5A] is a flow chart related to the image processing technology used in an embodiment. [FIG. 5B] is an image taken representing a sample of a droplet deposited on a medium, followed by grayscale conversion. [FIG. 5C] Filtering (for example, gradient processing) is performed on the captured image in FIG. 5B. [FIG. 6A] is an exemplary schematic diagram showing the production hierarchy of related product manufacturing; the technology disclosed herein can be, but not limited to, implemented at any level in the depicted hierarchy. [FIG. 6B] One of the manufacturing apparatuses is shown in plan view. [FIG. 7A] is an exemplary depiction of the use of a droplet measuring system. [FIG. 7B] is a flow chart about droplet measurement. [FIG. 7C] is a flowchart related to droplet verification. [FIG. 8A] is a cross-sectional depiction of elements in an industrial printing press inside a printing chamber. [FIG. 8B] is a sectional depiction of the industrial printing machine of FIG. 8A taken along the line B-B in FIG. 8A. [ Fig. 9 ] is a schematic diagram showing a comparison of the measured droplet positions with respect to the respective expected positions. [ Fig. 10 ] is a flow chart about the calculation of droplet volume. The subject matter defined by the enumerated patent scope claims can be better understood by referring to the following detailed descriptions, and the review of these descriptions should be carried out in conjunction with the attached drawings. Descriptions of one or more specific embodiments are set forth below to enable the construction and use of various implementations of the technology set forth in the claimed claims, but are not intended to limit the set forth claims, Rather, its application is described. Without being limited by the foregoing, this disclosure provides some different examples of a droplet measurement system that optically measures or images a plurality of droplets on a medium and uses image processing to identify Parameter values of various nozzles of a printing head. Each of these techniques can be implemented as a droplet measurement system, a printing press or manufacturing equipment, or software for implementing the techniques, in the form of a computer, printing press, or other device running the software, or by The form of an electronic or other device (for example, a tablet device or other consumer terminal device) produced by these technologies. Although specific examples are presented, the principles described herein may be applied to other methods, devices, and systems as well.

101: Flowchart

103-123: Steps

Claims (20)

A droplet measurement unit comprising: A housing comprising a measuring member for holding a membrane, an image capture system, and a membrane motor, wherein the image capture system comprises an optical assembly movable relative to the measuring member, and for taking images of droplets deposited on the membrane; and A mechanism for freezing the droplets after taking images of the droplets by the image capture system in the droplet measurement unit. The droplet measurement unit of claim 1, wherein the measurement member is coupled to a vacuum system to hold the membrane. The droplet measurement unit of claim 2, wherein the vacuum system is positioned so as to apply a vacuum at a surface of the measurement member. As the droplet measurement unit of claim 1, it further includes a film belt unit for supplying the film from a supply reel to the measuring member and receiving the film from the measuring member to a take-up reel, and wherein the film motor drives the supply reel and at least one of the take-up reel. The droplet measurement unit as claimed in claim 4, wherein the measurement member is coupled to a vacuum system to hold the membrane. The droplet measurement unit of claim 1, wherein the mechanism for solidifying the droplets includes an ultraviolet light source. The droplet measurement unit as claimed in claim 6, further comprising a capstan for transporting the membrane to the mechanism for solidifying the droplets. The droplet measuring unit according to claim 2, wherein the measuring member defines a plane, and the optical component is movable relative to the measuring member in a direction parallel to the plane. 7. The droplet measurement unit of claim 7, wherein the mechanism for solidifying the droplets is positioned downstream from the capstan. The droplet measurement unit according to claim 4, wherein the tape unit further comprises a capstan adjacent to the measurement member, and the take-up reel is adjacent to the mechanism for coagulating the droplets. A droplet measurement unit comprising: a chassis, which has a measuring member for holding a membrane; a motor for positioning the membrane along a surface of the measuring member, wherein the surface defines a plane; a mechanism for coagulating droplets after taking an image of the droplets deposited on the membrane by an imaging system; and The imaging system is movable in a direction parallel to the plane relative to the measurement member. The droplet measurement unit according to claim 11, wherein the measurement member is coupled to a vacuum system to hold the membrane. The droplet measurement unit according to claim 4, wherein the housing further comprises a winch, and the winch is adjacent to the measurement member. The droplet measurement unit of claim 4, wherein the housing further comprises a winch adjacent to the measurement member, and wherein the mechanism for freezing the droplets is positioned downstream from the winch. The droplet measurement unit of claim 11, wherein the mechanism for solidifying the droplets includes an ultraviolet light source. The droplet measurement unit according to claim 15, wherein the film is provided by a removable supply roll. The droplet measurement unit of claim 16, further comprising a capstan for transporting the membrane from the measurement member to the mechanism for solidifying the droplets. An inkjet printing machine comprising: a print head for dispensing liquid droplets; and The drop measurement unit of claim 1 or 10, wherein the print head is positionable for engagement with the drop measurement unit so as to measure drops dispensed by the print head. An inkjet printing machine comprising: a print head for dispensing liquid droplets; and A droplet measurement unit, the droplet measurement unit includes: A housing containing a measuring member holding a membrane for receiving droplets of a liquid on the membrane, an imaging system for imaging the droplets on the membrane, for solidifying after imaging A mechanism for the droplets, and a film motor, wherein the image capture system includes an optical assembly that is movable relative to the measurement member, and wherein the droplet measurement unit is relatively two-dimensional Move the print head. The inkjet printer of claim 19, wherein the droplet measurement unit is movable relative to the printing head in three dimensions.

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