TWI835210B - 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 the rapid measurement of droplet parameters in industrial printing systems.

More and more industrial processes are turning to printing systems to create product laminates. These printing systems deposit a fluid that is then solidified or hardened to form a permanent laminate for a specific product. These processes are particularly useful for microelectronic products or products with arrays of quasi-electronic structures. For example, these 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 produce individual, approximately uniformly sized droplets. This precise control of both the volume and position of deposited droplets contributes to high end product quality as well as high resolution, small size products and reduced manufacturing costs. For example, in one application, the manufacturing of organic light emitting diode (OLED) displays, the ability to precisely deposit ink can help produce smaller, thinner displays at lower cost. , and a display with better resolution. Note that when the term "ink" is used to refer to a deposition fluid, the deposition fluid is essentially colorless and is deposited into a structure of a thickness that will "build" a permanent stack of layers in a device. That is, the color of the fluid itself is generally not important in the sense of an ink used in traditional graphic printing applications.

Not surprisingly, in these applications, quality control depends on the deposited ink droplets uniformity, in size (droplet volume) and precise location, or at least understanding, to produce permanent products that consistently meet quality standards for stack alignment accuracy and/or stack homogeneity Stacking, variation in these characteristics is important. Please note that in an industrial printing system, the droplet uniformity of any particular nozzle also has the potential to change over time, whether due to statistical variation, changes in nozzle age, clogging, variations in ink viscosity or composition, temperature, Or other factors may occur.

What is needed is a droplet measurement system configured for use with an industrial printing process and, ideally, on-site with a printing system used by an industrial manufacturing facility. Ideally, such a droplet measurement system would provide extremely fast measurement of one or more droplet parameters, be easily maintained, and provide input that can be used to adjust printing, thereby enabling precise quality control for use in industrial product manufacturing processes. 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 from a plurality of nozzles of a print head is disclosed. The system includes: a film having a first side and a second side, the first side being positioned near the print head to provide a substrate to receive ink droplets from the plurality of nozzles; an image capture subsystem, Positioned to capture an image through the second side of the film, the image representing ink droplets received from the nozzle at a respective position of the nozzle, the image capture subsystem is configured to generate an output signal to transmit the captured image to an image processing system; and a mechanism for advancing the film to position a new portion of the film for a subsequent image capture process, wherein droplets from the plurality of nozzles of the print head are received at the first portion of the film Above the surface, the advancement of the film does not require repositioning of the print head or the imaging subsystem.

According to one aspect of the present invention, a method for measuring droplet parameters measures a parameter associated with droplets ejected from a plurality of nozzles of a print head. This method includes: providing a first A film with one side and a second side, and positioning the first side near the print head to provide a substrate to receive ink droplets from the plurality of nozzles; using an image capturing device to take pictures through the second side of the film an image representing ink droplets received from a nozzle at a respective position of the nozzle and correspondingly generating an output signal to convey the captured image to an image processing system; and advancing the film for a subsequent image capture The process positions a new portion of the film in which droplets from the nozzles of the print head are received on the first side of the film in a manner that does not require repositioning of the print head or the image capture device. .

According to one aspect of the present invention, a device includes: a printer for receiving a first substrate, the printer having a print head, the print head including a plurality of nozzles, the plurality of nozzles for ejecting an ink on On the first substrate, the ink contains a liquid that will 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 from the plurality of nozzles of the print head. The system includes: a film having a first side and a second side, the first side being positioned near the print head to provide a second substrate to receive ink droplets from the plurality of nozzles; an image capture device The system is positioned to capture an image through the second side of the film, the image representing the ink droplets received from the nozzle at a respective position of the nozzle, and the image capture subsystem is used to generate an output signal to capture the image. conveying the image to an image processing system; and a mechanism for advancing the film to position a new portion of the film for a subsequent image capture process, wherein droplets from the plurality of nozzles of the print head are received at the portion of the film On the first side, advancement of the film does not require repositioning of the print head or the imaging subsystem.

101:Flowchart

103-123: Steps

201: Droplet measurement system

203: Measurement window

205:Arrow

207:Reel

209: Vacuum port

211: winch

213:Chassis

301: Droplet measurement system

303: Inspection window

305:Optical components

307:Camera

309:Light source

311: Stepper motor

313: Direction indicator arrow

315: winch

317:UV curing rod

319: Interface and Control Panel

321:Film rolling motor

323:Film rolling motor

403: Vacuum port

405:Supply reel

407: Storage roll

409: Frame and Optical Chamber

411: Direction indicator arrow

412: Direction indicator arrow

415: Direction indicator arrow

501: Methods for performing droplet measurements

503-533: Steps and related items

551:Sample image

571:Sample image

601: Different implementation levels

603: Non-transitory machine-readable media

605:Computer

607:Storage media

609: Manufacturing device

611: Semi-finished flat panel device array

613:Portable digital device

615:TV display screen

617:Solar panel

621:Multi-chamber manufacturing equipment

623:Conveyor module

625: Printing module

627: Processing module

629: Input load lock

631:Transport chamber

633: Environmental buffer chamber

635:Air mask

636:Transport chamber

637: Output loading latch

639: Nitrogen accumulation buffer

641:Cure 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 system

711B: Optical recovery under plane

711C: Flat light source supply

713:Dimensional plane

715: Measurement area

717:Light source

719:Light Delivery Optics

721:Light sensor

723:Reply Optics

725: Focusing 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 configurations within industrial manufacturing equipment

803: Printed closed chamber

805: Second closed environment

807: Print head assembly

809:Arrow

811:Sliding lever

813:Substrate

815:Floating platform

817: Droplet measurement system

819: Parking position

821:arrow

823: Dimension reference

825: Y axis

857:Transfer direction

865:Nozzle

867:Nozzle interval

901: Chart

1001:Flowchart

1003-1013: Steps and related items

[Figure 1] is a flow chart illustrating a technique for measuring parameters of a droplet.

[Figure 2] is a close-up perspective view of a droplet measurement system.

[Figure 3] is a cross-sectional view of a droplet measurement system.

[Figure 4A] is another perspective view of a droplet measurement system.

[Figure 4B] is a perspective view of the 4A droplet measurement system taken from the high point of arrow B-B in Figure 4A.

[Fig. 5A] is a flow chart related to the image processing technology used in an embodiment.

[Figure 5B] is an image taken of a sample representing a droplet deposited on a medium, followed by a grayscale conversion.

[Fig. 5C] The captured image of Fig. 5B is filtered (for example, gradient processing).

[Fig. 6A] is an illustrative schematic diagram showing the production hierarchy of related product manufacturing; the technology disclosed herein can, but is not limited to, be implemented at any level of the depicted hierarchy.

[Fig. 6B] Shows the manufacturing equipment in a plan view.

[Figure 7A] is an exemplary depiction of the use of a droplet measurement system.

[Fig. 7B] is a flow chart regarding droplet measurement.

[Figure 7C] is a flow chart regarding droplet verification.

[Figure 8A] is a cross-sectional depiction of components in an industrial printing press located inside a printing chamber.

[Fig. 8B] is a cross-sectional depiction of the industrial printing machine of Fig. 8A taken along line B-B in Fig. 8A.

[Figure 9] is a schematic diagram showing the measured droplet position compared to one of the respective expected positions.

[Figure 10] is a flow chart regarding droplet volume calculation.

The subject matter defined in the enumerated patent scope claims can be better understood by referring to the following detailed descriptions, which should be reviewed in conjunction with the attached drawings. The description of one or more specific embodiments is set forth below to enable one to construct and use various implementations of the technology listed in the claims, but is not intended to limit the enumerated scope of the claims. Rather, it illustrates its application. Without being limited by the foregoing, the present disclosure provides several different examples of a droplet measurement system that optically measures or images multiple droplets on a medium and uses image processing to identify artifacts. Parameter values of various nozzles of a print head used in industrial manufacturing. These various techniques may be implemented as a drop measurement system, a printing press or manufacturing equipment, or software for executing the techniques, in the form of a computer, printing press or other device running the software, or in the form of The form of an electronic or other device (for example, a tablet device or other consumer terminal device) manufactured by these technologies. Although specific examples are presented, the principles described herein may be applied to other methods, devices, and systems.

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 various printhead nozzles associated with and/or generating the droplets. One parameter and one value. More specifically, as will be explained below, some embodiments use a deposition tape located in a printer access bay for test printing with ink from various nozzles simultaneously. This tape in advantageous embodiments may be any medium capable of receiving ink droplets, and in the noteworthy embodiment described below, it consists of a transparent film specially treated to hold moist ink droplets, Much like photosensitive photo paper. And, 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., represent a material that will be deposited and solidified to form a panel An encapsulating layer of a device (such as a display or solar panel), or a light-emitting element of such a device). This transparency enables imaging of clusters of one or more droplets for a set of multiple nozzles; in alternative embodiments, droplet deposition can be associated with both the film and the imaging nozzle position (behind the film) are separated from each other to provide extremely fast measurement 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 printing press (thus during the printing press/manufacturing process When the equipment is used for other purposes). When a printhead is parked, it is aligned in a specific manner relative to one or more printheads. The drop measurement system is engaged in a positioned manner to bring the deposition medium (eg, the transparent film described above) into proximity with the one or more print heads. It then causes nozzles from one or more printheads (e.g., a window or subarray containing a subset of all nozzles) to eject a droplet or a series of droplets (e.g., 2, 5, 10, etc.), The droplets are caused to land on the medium at a desired location close to a specific nozzle. During or after this period, the film is imaged from the side of the film opposite the print head, effectively passing through the transparent film; in other words, the film is positioned precisely at a normal deposition distance relative to the measured nozzle. (e.g., <1.0 mm) and measure the nozzles simultaneously (or shortly after) by firing multiple nozzles simultaneously, and then by capturing an image through the other side of the film, allowing the resulting captured image to be Image processing to obtain droplet parameter values.

Some advantages of the features of the various embodiments described so far are noted below. First, the optical processing of deposited droplets through transparent films is particularly suitable for very large print heads with hundreds to thousands of nozzles, that is, the optical processing can be performed immediately without the need for additional movement of the print head, droplet measurement system or other components. Second, the droplet measurement system can be configured to measure droplets from multiple nozzles simultaneously; for example, it is possible to eject droplets from hundreds of nozzles and measure them simultaneously. Such simultaneity can be greatly facilitated when compared to systems that optically image individual droplets in flight (e.g., one drop at a time) with thousands of printhead nozzles (e.g., as used in some industrial manufacturing Measurement of droplets among applications). For systems that rely on dynamically updated measurements of droplet parameters, such simultaneity may be important in order to combine droplets in a way that mitigates variation or compensates for variation in producing accurate target volumes, as it does not require an impact on print time or manufacturing. There are significant disruptions in output. For a drop measurement system linked to one or more stationary print heads located in a maintenance station, this provides the ease with which any of the thousands of printing nozzles that can be used in some industrial processes can be And use it accurately. Furthermore, the deposited film strip or its processing can be specifically tuned to match the chemistry of a particular ink being tested (i.e., so that its properties can be more easily and accurately determined by optical mechanisms). It should be apparent that the described technology provides enhanced accuracy and lower Cost, for example, particularly for price-sensitive consumer products such as flat-panel high-definition televisions ("HDTVs").

In at least one design described below, the droplet measurement system utilizes a roll-to-roll mechanism to load a transparent film, which allows the film to be advanced over an imaging area like a roll of film tape, allowing for Intermittent replacement of measured film tape rolls. In addition, the droplet measurement system can also advantageously use a vacuum system that tightly adheres to the portion of the film strip being deposited, forming a flat and precise positional relationship with each other, simulating a deposition surface used online. The drop measurement system may also optionally include a curing station to cure/air-dry the ink so that after measurement, additional ink is prohibited from spreading to any other part of the system; please note that this is not the case in some embodiments. If necessary, for example, the film may also be selected or treated to possess properties such that the ink droplets become immobilized once deposited. Furthermore, as previously mentioned, the droplet measurement system can optionally be mounted on a three-dimensional movable carrier, in other words, to engage a parked print head 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 thousands of nozzles) to be used below a printing surface (e.g., in an access bay) with the aforementioned droplet measurement system attached. To keep the parameters fixed when measuring the parameters of different groups of nozzles. One envisioned deposition process advances a roll of film tape so that a window of unused film tape is adjacent to selected print heads. These print heads are then controlled so that all of their nozzles eject a specific amount of ink, which are then affixed to the above the membrane strip; simultaneously, a coaxial camera from below (e.g., inside a housing or chassis of the droplet measurement system) images all deposited droplets in parallel with the image sensor (again, by looking through the Image capture of one opposite side of the film strip means that essentially neither the film nor the droplet measurement system has to be moved or repositioned for analysis). If desired, the camera (or image capture optics) can be configured to move relative to the droplet measurement system, for example, to provide scanning activity between a range of nozzles, focus adjustment, or other assistance as needed. .

The output of an image processing system is then provided suitable for verifying nozzles or otherwise Control the droplet parameter data for printing. Immediately following any particular measurement iteration, the film tape and droplet measurement system are each pushed into place, the used film tape is cured and/or rolled up, and the process is repeated immediately as needed, or at a later time. Click Repeat. In designs where the tape cannot be reused once printed, a used tape roll (or a tape cassette with spools and winches for new and used tape) can be molded Groups are recycled or replaced periodically on a group basis. Note that in one envisioned application in which a manufacturing mechanism is used continuously (e.g., to print laminates for OLED television screens, or otherwise fabricate laminates for one or more flat panel devices), when a previously The substrate is removed, the print head is parked to accept the aforementioned droplet 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 similarly returns to the service station again (when a new substrate is loaded) to start measurements where the system previously stopped. In this way, repeated measurements can be collected for a nozzle and used on a rolling basis to establish a statistical distribution for each printing nozzle or combination of nozzle waveforms across many measurements (e.g., as in the patent application in the priority statement As described in these patent applications, which are incorporated herein by reference), a moving measurement window is used that advances cyclically through all printing nozzle sets to continuously update measurement data.

Note that all process steps listed above (and below) can be implemented in a variety of ways. For example, in one embodiment, these steps are performed by one or more computers or other types of machines, such as by special-purpose hardware or by general-purpose hardware configured to operate as a special-purpose machine. a printing press or one or more manufacturing devices). For example, in one contemplated design, one or more operations may be executed by one or more of these machines, which store data on a non-transitory machine-readable medium such as firmware or Actions controlled by software instructions. The instructions are written or designed in such a way that they have a specific structure (structural characteristics) that, when ultimately executed, cause the performance of one or more general purpose machines (e.g., processors, computers, or other machines) It must be like a special-purpose machine that has the structures necessary to perform the described tasks on the input operands, to take actions or otherwise produce output. "Non-transitory machine-readable medium" means any tangible (i.e., physical) storage Storage media, regardless of how data is stored on it, including, but not limited to, random access memory, hard disk memory, optical memory, floppy disks or CDs, server storage devices, volatile memory, and other tangible mechanisms , where the instructions can later be retrieved by a machine. The machine-readable medium may be in a stand-alone form (e.g., a program disk) or implemented as part of a larger machine, such as a laptop, a portable device, a server, a network, a printing press, or other device sets consisting of one or more devices. These instructions may be implemented in different formats, for example, as metadata that effectively invokes a specific action when called, as Java code or scripts, or as code written in a specific programming language. (for example, implemented as C++ code), implemented as a specific processor instruction set, or implemented in some other form; the 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 may be implemented substantially as instructions stored on non-transitory machine-readable media, and any of which may be implemented using a "3D Print" or other printing process to manufacture products. Depending on the product design, these products may be manufactured into a salable form or as a preparatory step for other printing, curing, manufacturing or other processing steps that will ultimately produce a finished product for sale, distribution, export or imported. Depending on the implementation, instructions on a non-transitory machine-readable medium may be executed by a single computer, and in other cases may be stored and/or executed on a distributed basis, e.g., using a or Multiple servers, network client devices, or application-specific devices. Each of the functions described may be implemented as part of a consolidated program or as a stand-alone module, stored together on a single media format (e.g., a single floppy disk), or on multiple separate storage devices. .

In addition, it should be noted that the word "transparent" is a relative term when used with a film or film tape, that is, it means that it is photographed through the second side of the film tape and deposited on the first side of the film tape. The 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 strip is colorless and has extremely high visible light transmittance, and the visible light is used to capture images of droplets from respective nozzles where the droplets are deposited In such a way that the droplets of the respective nozzles are arranged in an array on the first surface of the film strip (that is, located at respective positions related to the respective nozzles). In another embodiment, the film strip has a certain degree of color, for example, optimized for a specific ink to enhance the imaging properties of the ink. In yet another embodiment, radiation rather than visible light is used to image droplet properties.

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

FIG. 1 shows a flow chart 101 illustrating some of the techniques described herein. As previously indicated, it is necessary to measure the values of droplet parameters of droplets produced by a plurality of nozzles simultaneously. In order to perform this action as quickly as possible, the embodiments disclosed herein rely on receiving an image shot of a deposition surface of such droplets (i.e., a rapid shot of droplets collectively representing the plurality of nozzles), and image processing to calculate from this image shot one or more desired parameters relative to the plurality of nozzles, respectively. As indicated by reference numeral 103, the one or more print heads being analyzed cause a range of nozzles or an array of nozzles to fire, thereby depositing one or more droplets, respectively. For example, a hypothetical printhead may have two thousand nozzles, and these nozzles are intended to be measured simultaneously in groups of one hundred nozzles. For each measurement iteration, the printhead and/or drop measurement system is aligned, and the windows or groups of one hundred nozzles to be measured are identified and caused to eject 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 drops, such as 2, 5, 10, 12, 20 or other numbers of drops. Note that in some contemplated designs (e.g., OLED applications), the droplet size is typically quite small, including picoliter (pL) sized droplets with diameter factors of tens of microns or less, deposited with near-micrometer precision.

As described in the patent applications incorporated by reference in the priority statements, depending on the application, it may be necessary to measure the position of the deposited drop, the drop velocity, the drop volume, the nozzle warpage, or a component of each nozzle. or multiple other parameters. In short, in one embodiment, for each sink In terms of accumulated droplets, it can be expected that the droplet quality of each nozzle is important; that is, if one nozzle is in a stopped position relative to the others (nozzle warping) or produces deviating liquid droplet trajectory or an inaccurate droplet volume, which may produce inhomogeneities in a deposited film. This unevenness may cause quality defects in precision products such as display devices. Understanding this defect on a nozzle-by-nozzle basis enables it to achieve: Nozzle pass/fail: It can identify nozzles that are not working or have other undesirable characteristics and exclude them from the print job, where software-planned printing methods can be used A different nozzle deposits a droplet in a predetermined area; eruption time mitigation: positional imperfections in the scan direction can be potentially corrected by changing the timing or voltage of the nozzle drive pulse, for example, making the nozzle erupt earlier or later , or eject at a larger or smaller speed; in addition, it is also possible to use an alternating driving pulse shape, as disclosed in the patent application incorporated by reference in the priority statement.

Planned droplet combinations: Detected differences between nozzles can be accepted and deliberately used to calculate droplet combinations based on respective desired values to achieve an accurate result, for example, falling within a specific tolerance; For example, if one nozzle is measured and judged to produce the expected droplets of 9.89 picoliters (pL), a second nozzle is measured and judged to produce the expected droplets of 10.11 pL, and it is expected to produce a total of If a volume of 20.00 pL of ink is placed at a specific target location, the two nozzles can be specifically designated and planned to print to deposit this particular droplet combination; please note that the results that can be obtained are different from those that simply average the differences without taking into account Systems with specific fill volumes or fill tolerances (e.g., ±0.50% of target volume); and pre-screening of drive waveforms: As shown in the patent application incorporated herein by reference in the priority statement, it is possible to pre-screen each nozzle Programmable drive waveforms (eg, a selection from sixteen preselected drive waveforms) are available for inventory use during printing, with each waveform selected to achieve a specific deposition characteristics, accuracy, and desired results.

Please note that droplet parameters may vary from day to day and even from deposition to deposition, e.g. For example, it depends on ink quality, temperature, nozzle age (e.g., clogged), and other factors. In order to ensure printing accuracy, therefore, in some embodiments, it may be necessary to remeasure these values from time to time. It should also be noted that each deposited droplet may be slightly different, even from a single nozzle; therefore, in one embodiment, each nozzle (or combination or pairing 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 degree of confidence in the relative expected value of the droplet parameter. For example, it can measure "24" droplets from each nozzle-waveform pair to average (and therefore obtain (an expected value), where the number of measurements n (n = 24) helps reduce uncertainty due to measurement error or statistical variation. It can be on a rolling basis (e.g. all measurements are stored, and every two hours the 6 latest measurements per nozzle replace the 6 oldest measurements) or on a one-time basis (e.g. during start-up Re-measure all nozzles at once) to update a specific measurement total. One skilled in the art will envision many variations. For example, a nozzle may be measured to determine an expected value, and if the measured (desired) value lies outside the ±5% band of an ideal value, the nozzle is lost. Qualifications for use; 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 nozzles, perhaps each 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 if it is to be commercially viable. It must be at an acceptable consumer price point, and this generally means that the printing process produces as much product as possible, with as much accuracy as possible (and with as little product waste), and with as little product waste as possible. Downtime. The technology disclosed in this article makes far faster measurements, and therefore more feasible measurements, possible.

Returning to Figure 1, in order to achieve this effect, the droplet measurement technology proposed in this disclosure also captures droplets from many nozzles at one time, reference numeral 105. In other words, as opposed to "one at a time" on the fly As a system for imaging droplets, embodiments of the present disclosure rely on simultaneity to measure as many nozzles as possible simultaneously. Thus, image capture can be used to efficiently obtain an image containing many droplets from a large nozzle array, for example, droplets deposited in multiple rows and columns, 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 illustrates 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 print head, which facilitates velocity measurement, (b) Capturing images simultaneously captures both droplets and nozzles (109), which assists in measuring the positional offset, warpage, or velocity of droplets from respective nozzles, (c) simultaneously ) droplets from nozzles (111), for example, actually measuring forty or more nozzles at a time, and (d) not capturing one droplet per nozzle, but simultaneously measuring a droplet containing multiple (e.g. , 5 or more) a collection of droplets. Please note that in the latter case, the image processing software can detect a pooled deposited volume (e.g., volume), or a range of droplet locations near an expected location, and can identify individual droplets at once from a single captured image. mean, or other statistical parameters such as distribution (dispersion). Please note that, depending on the embodiment, this may require a standard to be pre-measured and stored in the system; for example, when the ink droplet is immobilized in the deposition medium (i.e., film strip), it may be difficult to detect Measuring droplet volume; this determination can be based on the droplet diameter, the color (or grayscale) value of a deposited droplet, or the use of other methods to determine, and use these values to compare with a calibration standard to produce an accurate numerical estimate.

As indicated by numerals 115 and 117, the system (e.g., using an image processor running appropriate software) then calculates the measured values and stores them in memory (e.g., such as on a removable hard drive). of random access memory). In one embodiment, these values are stored individually (i.e., once for each measurement of each parameter to be measured for each nozzle), while in another embodiment, they can be stored in a Stored in a manner that represents a mixing distribution (e.g., as a mean, total number of measurements, standard deviation, etc.) of a specific parameter for a specific nozzle. Reference numbers 119, 121 and 123, As mentioned previously, measured values can optionally be used to calculate a statistical distribution, to perform nozzle qualification/verification, and to perform "smart batching" where print scans are planned to Match droplets with expected properties in a desired way.

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

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

Figure 3 shows an internal cross-sectional view of the droplet measurement system 301. The system similarly includes a viewing window 303 through which images are captured, and an optical system including an optical component 305, a camera 307, and a light source 309. The stepper motor 311 selectively advances the optical assembly 305 linearly relative to the viewing window 303 , that is, back and forth in the direction indicated by arrow 313 . Please note that in this specification, "camera" can optionally refer to any type of light sensor, meaning that it may use a simple line sensor including individual optical sensors, and for example , "sweeping" the line sensor back and forth to use the stepper motor 311 to image the entire observation window 303. In other embodiments, the camera is captured by any conventional mechanism, such as using a commercial light-sensitive camera, a charge couple device array, an ultraviolet or other invisible radiation camera, or using In other ways, an image of an array of pixels representing the viewing area is captured. Note that camera movement (ie, scan movement) is not necessary for all embodiments. In the depicted embodiment, optical assembly 305 also contains a beam splitter internally that passes light from the light source (e.g., upward to viewing window 303), but uses a beam splitter in the direction of camera 307. Reflectors turn returning (reflected) light. It should be clearly visible that light from the light source passes through the viewing window, passes through the clear film strip, reflects from the print head (not shown in Figure 3), returns again through the clear film strip, and is subject to any focusing or other optical actions, being photographed and Processed for analysis. A captured image thus provides a visible indication of the position of each nozzle being measured (for example, the image was captured from a reflection of the nozzle plate) and also shows the overlap of any deposited droplets (which are transparent but distinguishable from the film) cover. In other words, in the process envisaged (especially for OLED display manufacturing, for example, for an encapsulation layer), the deposited material is translucent and therefore does not block the image capture of the nozzle plate. Figure 3 also shows a winch 315 for transporting 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 panel 319 for control of various system components and control of image capture; this interface and control panel 319 also controls the transportation of film tapes, for example, by controlling respectively Film rolling motors 321 and 323 are used for film storage and supply rolls (which are not respectively indicated in the figure). Depending on the embodiment, image processing may be performed locally on the interface and control panel 319 or, alternatively, in a processor located in the manufacturing facility or on a remote computer.

4A and 4B show a perspective view of the droplet measurement system 301 of FIG. 3 . FIG. 4B represents a perspective view of the backside of the unit relative to FIG. 4A , that is, a view from the vantage point provided by arrow B-B in FIG. 4A . More specifically, the figures show an inspection window 303, a vacuum port 403, a UV curing rod 317, a supply roll 405 and a receiving roll 407 for the film tape, and a frame and optical chamber 409 (here Holds interface and control board 319, as previously described). During operation, it supplies unused film strips in the direction indicated by arrow 411 and tightly adheres to the inspection window 303, as mentioned previously. From this point, the film is advanced on capstan 315 downwards along arrow 412 toward UV curing rod 317 for use as previously described. way. The operation of the aforementioned UV curing rod 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 the storage roll 407 substantially as indicated by arrow 415 . It should be obvious that the entire unit is modular, providing ease of removal and repair, for example, removing one of the transparent deposited film tapes to complete the storage roll 407, and replacing the supply roll 405 with a new one. of feed.

Figure 5A presents a flow chart associated with an embodiment 501 of a method of performing droplet measurements. As mentioned previously, this may require performing in-situ measurements, that is, measurements directly within a manufacturing facility, to dynamically update the values of one or more droplet parameters in response to 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 when a new substrate is being loaded, unloaded, cured after deposition, or during other idle periods relative 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 maintenance operations. This maintenance action may include various calibrations, printhead replacement, nozzle cleaning or other quality treatments, droplet measurement as contemplated by this disclosure, or other uses. As will be explained more fully below, for OLED display manufacturing applications (as well as the manufacturing 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 "park" position would be in a second controlled environment chamber, for example, in a chamber that can be accessed externally (e.g., for printhead replacement) without having to communicate with the entire manufacturing equipment or printing press. 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 flow block 507, if printing is for one of the moving windows of nozzles (e.g., where different nozzle sets are moved between print passes as previously mentioned when substrates are loaded or unloaded) measure or remeasure) Executing on an intermittent basis, the system retrieves the initial address to locate the DMU and captures 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 process can be performed by linking the DMU (and its camera) to imaging and thereby finding the corner nozzles of each array, and using an approximate position addressing and search process (e.g., spiral search algorithm) )) are performed, for example, as described in previously cited US Patent Application No. 14/340403. The system controls the drop positioning very precisely, for example, to a precision of about one micron, and generally recalibration of the print head positioning of the drop measurement system is not necessary unless a system component is manually replaced (e.g. , the DMU or a print head was removed or repaired). When a transparent film strip (ie, 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 If each nozzle is intended to measure multiple droplets). At the same time, the imaging system in the DMU images the deposited ink and the position of the nozzle (for example, photographing the light reflected by the print head through the transparent film tape and ink). Please note that, as shown at 511, in one embodiment, the image capture is performed in color to enable identification of the ink concentration in any deposited ink droplet (e.g., when translucent, which will depend on the material or thickness Gives subtle color properties). As shown at 511 , a captured image may be filtered (for example, for color, intensity, gamma, or one or more any other desired parameters) to produce a filtered image; then After this filtering action (or as part of this filtering action), the captured image is converted into grayscale, reference numeral 513 . Please note that multiple images can also be generated from this process according to separate filters, for example, a first image representing the nozzle and a second image representing the deposited droplet; obviously there are many transformations. The image processing software then uses the output grayscale image(s) to identify the nozzle, the ink droplet, the positional difference between the nozzle and the ink droplet, the droplet volume, the droplet diameter, the droplet shape, and/or any Other required parameters (515/517). It should be apparent that measuring all of the above items is not necessary in all embodiments. For example, to calculate droplet volume in a systems that may not require imaging the nozzle itself or analyzing droplet shape or location. On the contrary, in this embodiment (if the spread range of multiple droplets is being analyzed), it is important to determine the amount of deviation of the droplet position or to perform color analysis to correctly calculate the volume. The parameters measured will essentially depend on the implementation and the desired results. As shown at 517 , no matter what parameter is measured, the system calculates one or more measurement values, or an offset of a parameter, for example, using a selective criterion 519 , as described previously. This offset or value of a parameter may be calculated for drop or nozzle position, drop timing, or drop volume, or any combination thereof, as noted at 521 . The system then updates a repository of stored information either locally or remotely at the DMU (523), and it then stores the position for the next measurement iteration step and advances the tape, referring to optional process 525. The process is thus complete, ready for another measurement iteration step (which may be performed immediately, or at a later point in time, for example, following a subsequent substrate run pass).

Please note that as noted by reference numerals 529 to 533, calculation of 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) execution, and such processors typically store image data in processor-accessible memory, isolate individual image data for each nozzle, calculate parameters from the individual image data, and also store each nozzle parameter for processing The device can access the memory.

Figures 5B and 5C show sample images 551 and 571 respectively. The first of these, image 551, represents a photograph taken from a subset of approximately 40 nozzles of a print head. Note how the nozzles are slightly staggered from column to column to provide a choice of tight pitch variations within an intersecting scan axis (e.g., a droplet intended for a specific substrate location can be sprayed from either The nozzle array prints, providing in some embodiments a deposition accuracy better than, meaning less than, twenty microns). Figure 5B represents a color image, which can then be filtered and/or converted into a grayscale format as appropriate. It is also a grayscale image after this filtering or conversion action (because color is usually not used or allowed in patent applications. Schema). Note that in this example, the nozzles are not individually imaged or depicted, although This may be the case in other embodiments. The second image 571 (FIG. 5C) represents the image of FIG. 5B after filtering and gradient processing to identify the droplet diameter. In other words, Figure 5C shows white circles corresponding to droplet diameters with clearly discernible droplet boundaries. Image processing calculates a center of gravity (for example, by calculating the horizontal maximum diameter and vertical maximum diameter of these "circles" and by taking the medial Cartesian coordinate point along each diameter for each droplet associated with a specific xy rectangular coordinate position). This position can then be compared to the nozzle position to determine offset, and the system identifies nozzle-to-nozzle offset variation for print planning purposes. These photos may also represent droplet volume processing; for example, image processing software may 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 volume. Almost any desired droplet parameter can be measured in this way.

While a specific droplet measurement system is described above, applications to manufacturing and to an industrial manufacturing equipment/printer will be described below. In the following description, an exemplary system for performing such printing will be described, and more specifically, applied to the production of solar panels and/or display devices that can be used in electronic devices (e.g., smartphones). , smart watch, tablet, computer, TV, monitor, or other form of display). The manufacturing techniques provided in this disclosure are not limited to this specific scope and may, for example, be applied to any 3D printing application and to a wide range of other forms of products.

Figure 6A depicts a number of different implementation layers, collectively designated by reference number 601; each of these layers represents a possible independent implementation of the technology described herein. First, techniques such as those described in this disclosure may take the form of instructions stored in a non-transitory machine-readable medium, as represented by figure 603 (e.g., to control an executable of a computer or a printing press). instructions or software). For example, the disclosed techniques may be implemented as software configured to cause a manufacturing device (or an incorporated 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 be optionally implemented into a computer or network Part of, for example, a company that designs or manufactures components for sale or use in other products. Third, as illustrated using a storage media graphic 607, the previously described techniques may take the form of storing printer control instructions that, for example, when enabled, will cause a printer to behave in a manner that relies on droplet measurement and associated planning. One or more stacks in a component are fabricated (eg, scan path planning or nozzle qualification, as described herein). Note that press commands may be transmitted directly to a press, for example, via a LAN or WAN; in this context, the storage media graphic depicted may represent (but is not limited to) internal RAM, or a server RAM accessible from a computer, portable device, laptop, other form of computer or a printer, or portable media such as a flash drive. Fourth, as shown in the same manufacturing device icon 609, the techniques described above may be implemented as part of a manufacturing device or machine, or presented in such a device or machine (e.g., as a droplet measurement system in accordance with the techniques disclosed herein). , as a method of manufacturing, as software for controlling a droplet measurement system, etc.) within the form of a printing press. It should be noted that the particular depiction of manufacturing device 609 represents an exemplary printer device described below in conjunction with Figures 6B, 7A, and 7B. The technology described above can 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 Figure 6A, some such components are depicted In the form of an array 611 of semi-finished flat panel devices that will be separated and sold for inclusion in end consumer products. The depicted device may have, for example, one or more encapsulation stacks or other stacks fabricated using the methods described above. The technology introduced 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 (for example, such as an electronic tablet device or a smart phone), a television display screen 615 (for example, an OLED TV ), solar panels 617, or other types of devices.

Figure 6B illustrates a contemplated multi-chamber fabrication apparatus 621 that may be used to implement the techniques disclosed herein. In summary, the depicted device 621 includes some general modules or subsystems, including a conveying 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 by printing module 625 in a first controlled environment, while other Processing, eg, other deposition procedures such as deposition of an inorganic encapsulation layer or a curing procedure (eg, for printed materials), can be performed in a second controlled environment. Equipment 621 uses one or more mechanical loaders to move a substrate between modules without exposing the substrate to an uncontrolled environment. Within any particular module, it may be 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 transport module 623 may include an input loadlock 629 (i.e., a chamber that provides a buffer between different environments while maintaining a controlled environment), a transport 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 loading and unloading mechanisms, such as a flotation table to provide stable support of a substrate during a printing process. Additionally, an xyz transfer system, such as a split-axis or overhead transfer system, may be used to precisely position at least one print head relative to the substrate, and provide a y-axis transfer system for transport of the substrate through the printing module 625. It is also possible to use multiple inks within the printing chamber for printing, for example using separate print head assemblies so that, for example, two different types of deposition processes can be performed within a printing module located in a controlled environment. . The printing module 625 may include a gas hood 635 housing an inkjet printing system, with means for introducing an inert gas environment (e.g., nitrogen), and otherwise controlling the environment (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 transfer chamber 636 that also includes a loader for transporting a substrate. In addition, the processing module may also include an output load lock 637, a nitrogen accumulation buffer 639, and a curing chamber 641. In some applications, a curing chamber may be used to cure, bake, or dry a monomer film into a uniform polymer film; for example, two specifically contemplated processes include a heating process and a UV radiation curing process. .

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

Printing module 625 may be advantageously used in applications that deposit 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 input load latch 629. A loader located in the transport module 623 can move the substrates from the input load lock 629 to the printing module 625, and, immediately after a printing sequence is completed, the substrates can be moved to the processing module 627 for curing. Through repeated deposition of subsequent stacks, each of controlled thickness, pooled encapsulation, or other stack thicknesses can be established to suit any desired application. Also note that the techniques described above are not limited to encapsulation processes or OLED manufacturing, and can use many different types of tooling. For example, the configuration of the device 621 can be changed to place the modules 623, 625, and 627 in different parallel positions; in addition, it can also use more, fewer, or different modules.

Although Figure 6B provides one example of a set of interconnected chambers or fabrication components, many other possibilities obviously 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 equipment.

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

More specifically, Figure 7A provides an illustrative view depicting a drop measurement system 701 and a relatively large printhead assembly 703 having multiple printheads (705A/705B) each with numerous individual nozzles (705A/705B). For example, 707), where there are thousands or hundreds of nozzles. An ink supply (not shown) fluidly communicates with each nozzle (eg, nozzle 707), and a piezoelectric sensor (also not shown) is used to eject ink droplets under the control of a nozzle-by-nozzle electrical control signal. The nozzles are designed to maintain 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 a corresponding piezoelectric sensor, corresponding to the nozzle. A specific nozzle is pressurized and thereby droplets are ejected from that specific nozzle. In one embodiment, the control signal for each nozzle is normally at zero volts, and a positive pulse or signal level for a specific nozzle at a specific voltage is used to eject droplets from that nozzle ( One drop per pulse); in another embodiment, different tailored pulses (or other more complex waveforms) can be used from nozzle to nozzle. However, with the example provided in Figure 7A, it should be assumed that it requires measuring a droplet volume produced by a specific nozzle or a specific set of nozzles (eg, nozzle 707), where a droplet travels from the print head toward the carrier carrying a deposit. The film is ejected downwardly from the chassis 709 (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, it is advantageous for a target surface to be 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 "h" is typically on the order of a millimeter or less, and within an operating printing press there are thousands of nozzles (e.g., 10,000) whose individual droplets are individually measured in this way. nozzles) in which the deposition surface is incrementally changed or advanced into multiple windows where many droplets (e.g., tens to hundreds) will be imaged and measured simultaneously. Therefore, in order to accurately measure droplets optically from each nozzle, certain techniques are used in the disclosed embodiments to appropriately position the droplet 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 movement of at least part of the optical system (711A) (e.g., within dimensional plane 713) to accurately position a measurement region 715, which Measurement area 715 is provided by the system in close proximity to any nozzle or nozzle set producing droplets for optical calibration/measurement, and (b) in-plane optical recovery (711B) (e.g., thereby allowing close proximity to any nozzle Easy placement of the measuring area, even with a large print head surface area). Therefore, in an exemplary environment with approximately 10,000 or more printing nozzles, this mobile system can At least part of the optical system is positioned among, for example, 10,000 or so discrete locations near the discharge path of each individual nozzle in the printhead assembly. Optics are typically positioned so 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 the optical placement is often quite precise and challenging in terms of relative positioning of the print head assembly and the measurement optics/measurement area. In some embodiments, to assist with this positioning, optics (mirrors, mirrors, etc.) are used to adjust the orientation of a light capture path for sensing below the dimensional plane 713 originating from the measurement area 715 , so that the measurement optics can be placed close to the measurement area without disturbing the relative positioning between the optical system and the print head. This enables efficient position control in a manner that is not limited to a millimeter-scale deposition height h of each drop deposited and imaged, or to the large x and y width occupied by the inspection print head. Optionally, 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 is also possible to use other optical measurement techniques. In one of the optional features of these systems, the movement system 711A is optionally and advantageously fabricated as an xyz transfer system, which allows the drop measurement system to selectively move the print head assembly without moving the print head assembly during drop measurement. Engagement and separation. Briefly, it is conceived in an industrial manufacturing facility with one or more large printhead assemblies, each of which is "parked" from time to time in order to maximize production uptime. The maintenance station can perform one or more maintenance functions; considering the large size of the print head and the number of nozzles, it may be expected to perform multiple maintenance functions on different components of the print head at one time. To this end, in such an embodiment it may be advantageous to move the measurement/calibration device around the print head rather than moving the print head around these devices. [This thereby also allows other non-optical maintenance procedures to be included, for example, on other nozzles if necessary. ] To facilitate these actions, the printhead assembly can be selectively "parked" as described above, with the system designating a specific group or range of nozzles 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 "park" the printhead assembly relative to the printhead assembly. Move at least part of the optical system and precisely position the measurement area 715 in a position suitable for detecting droplets ejected from a group of individual nozzles; using a z-axis movement to enable selection from well below the print head plane Optionally engage photorecovery optics to alternatively or additionally facilitate other maintenance actions other than optical calibration. Perhaps in other words, using an xyz movement system enables selective engagement of droplet measurement systems independent of other tests or test equipment 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. Please 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) and the measurement assembly is stationary, or where there is no need to park the printhead Component maker.

In summary, the optics used for droplet measurement will include a light source 717, a selective set of light delivery optics 719 (which directs light from the light source 717 to the measurement area 715 as needed), one or more light Sensor 721 , and a set of recovery optics 723 that direct light used to measure the droplet(s) from the measurement area 715 to the one or more light sensors 721 . Movement system 711A selectively moves any one or more of these components together with chassis 709 (e.g., with the imaging area) in a manner that allows post-droplet measurement light to be directed from measurement area 715 to a plane below ). In one embodiment, light delivery optics 719 and/or light recovery optics 723 use mirrors that are directed back and forth between measurement regions 715 along a vertical dimension parallel to the direction of droplet travel. The light, and moving system that moves each element 709, 717, 719, 721 and 723 becomes an integrated system during droplet measurement; this arrangement has the advantage that the focus does not need to be recalibrated relative to the measurement area 715. As indicated by reference numeral 711C, light delivery optics are also optionally used to provide source light from a location below the dimensional plane 713 of the measurement area, for example, with light source 717 and light sensor(s) 721 Both guide/collect light from below the measurement area, as summarized in the figure. As indicated by numerals 725 and 727, the optical system may optionally include lenses for focusing purposes, as well as light detectors (eg, for non-imaging techniques that do not rely on processing a multi-pixel "image"). Also note that the printhead assembly is "parked" At any point during this period, the selective use of z-movement controls for the chassis allows the optical system to selectively engage and disengage, and facilitates the precise positioning of the measurement area 715 near any group of nozzles. Such parking of the print head 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 flowchart associated with a procedure for droplet measurement of some embodiments. This program flow is generally designated 731 in Figure 7B. More specifically, as shown in reference numeral 733, in this particular procedure, the print head assembly is first parked, for example, at a maintenance station (not shown) of a printing press or deposition equipment. middle. A drop measurement device is then engaged (735) to the print head assembly, for example, by selective engagement of part or all of a drop measurement system by moving from below a deposition plane into one of the drop measurement system. An optical system is capable of measuring the position of droplets from many nozzles simultaneously. Referring to numeral 737, this movement of one or more optical system components relative to a parked printhead may be selectively performed in the x, y, and z dimensions.

As described in the patent application incorporated by reference in the priority statement, even a single nozzle and associated nozzle ejection drive waveforms (i.e., the pulse or signal levels used to eject a droplet) ) can also produce slightly different droplet volumes, trajectories, and velocities among each droplet. According to the teachings of this article, in one embodiment, the aforementioned droplet measurement system, as shown by reference numeral 739, selectively obtains n measurements of a desired parameter per droplet to deduce the expected properties of the parameter. Statistical credibility. 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 multiple A combination of these parameters. In one embodiment, "n" may vary with each 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 so that more measurements can be performed to dynamically adjust the measurement statistics of the parameter or to increase the confidence level. Obviously, many variations are possible. In conjunction with the previously described system, a measurement total can be established immediately (meaning That is, by taking multiple droplet measurements on a specific nozzle array during a single measurement iteration step (in other words, without moving the droplet measurement system to a different nozzle set), or by taking a single measurement and passing it on later. of measurements establishes a total number of measurements (e.g., 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 the droplet volume is being measured to obtain an accurate average representative of the expected droplet volume from a specific nozzle and a tight confidence interval. This enables selective planning of droplet combinations (using multiple nozzles and/or drive waveforms) while reliably maintaining the distribution of the mixed ink fill in a target area near an intended target (i.e., relative to the droplet mean mixture). As noted by optional process blocks 741 and 743, the contemplated optical measurement process ideally enables one-time real-time or near-real time measurement and calculation of the volumes (or other desired parameters) of many nozzles, for example, using a transparent film and shooting below the deposition plane (i.e., from the opposite side of the film from which it was deposited); using this fast measurement, it becomes possible to update the volumetric measurement frequently and dynamically, for example, to compensate for ink properties (including viscosity and constituent materials) , temperature, nozzle clogging or aging, and other factors that change over time. Based on this, for example, for a printhead assembly containing 10,000 nozzles, it is expected that the huge total number of measurements for each of the thousands of nozzles can be taken in minutes, allowing it to be performed frequently and dynamically. Droplet measurement. As mentioned earlier, in an alternative embodiment, droplet measurements (or measurements of other parameters such as trajectory and/or velocity) may be performed as a periodic intermittent procedure, on a schedule or between substrates. Droplet measurement systems can be placed in between (e.g., while substrates are being loaded or unloaded), or stacked under other components and/or other printhead service procedures to efficiently collect many data over many measurement intervals. points (and thus establish a statistical distribution representing each nozzle). Note that for embodiments that allow the use of alternating nozzle drive waveforms in a manner specific to each nozzle, this rapid measurement system facilitates scan path adjustment, nozzle pass/fail verification, and the generation of various nozzle waveform pairings. Programmatic droplet combinations of droplets, as omitted from the foregoing text and the priority statement of the patent applications incorporated herein by reference. Referring to numerals 745 and 747, by measuring the expected drop volume to an accuracy better than 0.01 pL, it becomes possible to plan very precise droplet usage, in which the droplet usage can also be planned (in ideal case) to 0.01 pL resolution, and where 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 is true for droplet position and/or velocity and/or nozzle warpage. For example, by measuring the expected position to an accuracy better than one micron (or another distance magnitude), it becomes possible to provide very precise deposition; the expected position can be measured to a specific Cartesian coordinate point and standard Within a certain range of differences (or, for example, 4σ , 5σ , 6σ distances near this point). Once adequate measurements are made for various droplets, filling involving combinations of such droplets can be evaluated and used to plan printing in the most efficient manner possible (748). As indicated by dividing line 749, the performance of droplet measurements may intermittently switch back and forth between the ongoing "online" printing process and the "offline" measurement and calibration process; please note that in order to minimize manufacturing system downtime, this Measurements are typically performed when the printer 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 may be specifically selected (or treated) to optimize the droplet properties (ie, the specific chemical or fluid properties of the ink) of the particular ink being analyzed. ) is captured to assist in image capture and/or analysis. For example, in some applications, the ink is a monomer that will later be cured by a UV light curing process to convert into a polymer; to assist in the capture of droplet properties, the transparent film Can be selected to have physical, color, absorption, immobilization, solidification, or other properties to enhance the predictive conditions of analysis of the material using imaging systems. Finally, reference numeral 753, the film (film tape) or the 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 interruption occurring between substrate printing actions. Whether engaged to re-measure all nozzles, or on a rolling basis, the same basic procedure of Figure 7B can be used to take measurements. For this purpose, when a new measurement (immediately following a previous measurement) When a droplet measuring device is added to the droplet measurement device after a substrate printing operation or immediately after a substrate printing operation), the system software loads an indicator indicating the next nozzle group for which measurement is scheduled (for example, for a second print head, the "upper left corner is located Nozzle window at nozzle 2,312"). In the event of an initial measurement (for example, in response to the installation of a new printhead, or a recent power-up, or a periodic procedure such as a daily measurement procedure), the above indicator will point to the first nozzle of a printhead. , for example, "Nozzle 2,001". This nozzle is associated with a specific imaging grid access or lookup from memory. The system uses the provided address to advance the droplet measurement system (eg, the previously described measurement area) to a location that corresponds to the expected nozzle location. Note that in a typical system, the mechanical throw positioning associated with this movement is quite precise, that is, 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 center of the nozzle and its position based on image analysis of the print head within a tiny 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 datum point that has a specific positional relationship relative to the desired set. A typical spacing distance between nozzles may be on the order of 250 microns, while the nozzle diameter may be on the order of 10 to 20 microns.

Figure 7C provides a flow chart regarding nozzle qualification. In one embodiment, droplet measurements are performed to generate statistical models for each and/or each of droplet volume, velocity, and trajectory for each nozzle and for each waveform applied to any particular nozzle (e.g., distribution profile vs. mean). Therefore, for example, if there are two waveform choices for each of the 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 per parameter (eg, volume) performed 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 unusually broad distribution, or an average that is so off track that it should be treated specially. This applied special processing is conceptually depicted in Figure 7C in one embodiment.

More specifically, it uses reference number 781 to generally represent a method. Data generated by the droplet measurement device are stored in 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, a normal random distribution is established for each variable subject to qualification, defined by a mean, standard deviation, and number of measured droplets (n), or equivalent quantities are used. Note that other distribution formats can be used (e.g., Student's-T, Poisson, etc.). The measured parameters are compared to one or more ranges (787) to determine whether the associated droplet can actually be used. In one embodiment, at least one range is applied to disqualify a droplet from being used (e.g., if the droplet has a volume that is too large or too small relative to the desired target, the nozzle or nozzle-waveform pairing may be excluded short-term use). To provide an example, if 10.00 pL droplets are required, nozzles or nozzle-waveform pairs linked to droplet averages that exceed this target by, for example, 1.5% (e.g., <9.85 pL or >10.15 pL) may be eliminated. It may also or alternatively use range, standard deviation, variance, or other measures of dispersion. For example, if one wants to have a statistical model of droplets with a narrow square distribution (e.g., 3σ < 1.005% of the mean), then droplets whose measured values do not meet this criterion can be excluded. It is also possible to use a sophisticated/complex set of standards that take into account multiple factors. For example, an abnormal mean value combined with a very narrow deviation may be acceptable, e.g., if the deviation (e.g., 3 σ) lies within 1.005% of the measured (e.g., abnormal) mean value μ, then one can use A related droplet. For example, if one wanted to use droplets with 3 sigma volumes within 10.00 pL ± 0.1 pL, one would exclude the creation of a nozzle-waveform pairing with a 9.96 pL average of 3 sigma values of ± 0.8 pL, but produce A nozzle-waveform pair with a 3 sigma value of ±0.3 pL and an average of 9.93 pL may be acceptable. Obviously, there are many possibilities depending on whichever rejection/exception criterion (789) is required. Note that this same type of processing can be applied to the flight angle and velocity of each droplet, meaning that it is expected that the flight angle and velocity of each nozzle-waveform pair will exhibit a statistical distribution and depend on the droplet measurements derived from Measurements and statistical modeling of the device, some droplets can be excluded. For example, a droplet whose mean velocity or flight path deviates from normal values by more than 5%, or whose velocity variability is outside a specified target, may be assumed to be excluded from use. Different ranges and/or evaluation criteria may be applied to each droplet parameter 785 measured and provided by the reservoir.

Note that droplets (and nozzle-waveform combinations) can be processed and treated differently depending on the rejection/exception criteria 789. For example, it may reject a particular droplet (791) that does not meet a required criterion, as previously described. Alternatively, it may be possible to selectively perform more measurements for the next measurement iteration of a particular nozzle-waveform pairing; for example, if a statistical distribution is too broad, it may be possible to specifically target 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). Referring to numeral 793, it is also possible to adjust a nozzle drive waveform, e.g., use a higher or lower voltage level (e.g., thereby providing larger or smaller speeds or more consistent flight angles), or reshape Adjust a nozzle-waveform pairing to produce a waveform 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 briefly earlier), a slow droplet can be ejected at an earlier point in time relative to other nozzles, while a fast droplet can be ejected later in time to compensate for the faster flight time. . Many such alternatives are possible. Finally, referring to numeral 795, any adjusted parameters (eg, burst time, waveform voltage level, or shape) can be stored and, optionally, applied to remeasurements if desired. One or more associated droplets. After each nozzle-waveform pairing (modified or otherwise) is qualified (passed or failed), the method then continues to the next nozzle-waveform pairing, reference numeral 797.

The aforementioned mechanism can also be used to measure nozzle warpage (and of course verify the nozzle's compliance on this basis). In other words, for example, if one assumes that a population of deposited droplets originates from a single common precise nozzle location, but is clustered off-center in a direction orthogonal to the scanning movement of the printhead substrate, then the nozzles in question may be located relative to the same exact nozzle location. Nozzles on a column or row are offset. Such abnormal shifts can lead to deviations from the idealized droplet eruption, which can be taken into account when planning the precise combination of droplets. In other words, any such "warpage" or individual nozzle offset is stored and used to verify the pass/fail of the nozzle or as part of the print scan planning, as mentioned earlier, to allow the printing system to One planning approach takes advantage of the differences in each individual nozzle rather than trying to even out those differences by averaging. In an optional variation, the same technique may be used to determine irregular nozzle spacing along the printhead scan direction (i.e., the fast print axis), although for the depicted embodiment, any such Errors are attributed to corrections for droplet velocity deviations (e.g., any such spacing errors can be accommodated by corrections to nozzle velocity, e.g., due to small changes in the drive waveform for that particular nozzle) By). To determine the cross-scan axis warpage of a nozzle that produces a cluster of droplets, individual trajectories are actually plotted inversely (or otherwise mathematically transformed) relative to other measured trajectories for the same nozzle and used to identify the under-view The average position of one of the specific nozzles across the scan axis. This position may deviate from one of the expected positions of the nozzle, which may be evidence of nozzle warpage.

As previously described and within the meaning of this description, one embodiment establishes a statistical distribution for each nozzle for each measured parameter, for example, for volume, velocity, trajectory, nozzle warpage, and possibly other parameters. . As part of these statistical procedures, individual measurements may be discarded or used to identify errors. To give some examples, if a droplet measurement is found to have a value that has been removed from other measurements of the same nozzle, then the measurement may represent an eruption or measurement error; in one embodiment, if the deviation To a point that exceeds a statistical error parameter, the system discards the measurement. If no droplets are seen at all, this may be evidence that the droplet measurement system is in the wrong nozzle (wrong location), has an eruption waveform error, or has a failed nozzle under inspection. 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 through 7C are not individually invoked, they essentially perform the depicted measurement procedures for each available alternative waveform for use with each nozzle. For example, if each nozzle has four different piezoelectric drive waveforms to choose from, the measurement procedure can generally Can be repeated 4 times for each group of nozzles; if a particular implementation requires establishing a statistical distribution based on 24 droplets per waveform, then a nozzle can have 96 such measurements (24 for each of the four waveforms) ), where each measurement is used to obtain the statistical mean and distance for each of the droplet velocity, trajectory, and volume, as well as the estimated nozzle position (e.g., for assessing nozzle warpage). In one 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 printing planning. These parameters can also be used to decide whether to maintain (and store) a waveform for use in printing (e.g., as part of a preselected set of allowed waveforms), or to select a different waveform and measure multiple portions of that waveform. parameters.

Through the use of precise mechanical systems and droplet measurement technology, the disclosed method allows for extremely high-accuracy measurement of individual nozzle characteristics, including the average of each of the aforementioned parameters (e.g., volume, velocity, trajectory, nozzle position, and other parameters). Droplet Measurement. It should be appreciated that the technology described promotes a high degree of consistency in the manufacturing process, especially for OLED device manufacturing, and thus enhances reliability. The teachings presented above help provide a better solution by providing control efficiencies, particularly regarding 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 accuracy in the manufacturing process.

Figure 8A shows a cross-sectional view 801 of a typical configuration within an industrial manufacturing facility (eg, associated with a printing press within such facility). More specifically, it can be seen that printing is performed within a printing enclosure 803 so that the surrounding environment can be controlled ("controlled environment"); this control is typically performed to exclude unacceptable dust particles, Or otherwise perform printing in the presence of a specific gas composition (eg, nitrogen, inert gas, etc.). In summary, a substrate 813 is introduced into the printing press using an environmental buffer chamber (not shown) and transported to a floating support table 815 using a mechanical loader, which also passes through one or more of the substrates. Detection of fiducial points (these fiducial points and a camera or other optical detector used to detect precise substrate position are not shown in Figure 8A) properly align the substrate for printing. Printing is performed using a print head assembly 807 which moves along a "slow print axis" direction. The traveler 811 moves back and forth (as depicted by arrow 809). Printhead assembly 807 is depicted as a single object, but it can be a complex assembly carrying multiple printheads (e.g., 6, 10, or other numbers), each having hundreds to thousands of printing nozzles (e.g., Each has two thousand nozzles). Printhead assembly 807 deposits a liquid ink to a precise thickness at precise locations on substrate 813 , where the ink contains a material that will form a permanent stack of one or more products intended to be manufactured on substrate 813 . For example, this material can be an organic or inorganic material, a conductor or insulator, a plastic, a metal, or some other type of material. In a typical application, substrate 813 is over a meter wide and several meters long, and is used to simultaneously fabricate multiple OLED displays arranged in an array on the substrate; each stack is deposited across all such "substrates" Part of an integrated printing process for "panels" (i.e., across multiple such displays in production) in which individual displays are ultimately 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 devices, 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 to a curing chamber (not shown) where the deposited ink can be cured and dried. , heated or otherwise treated to impart durability to the deposited material. Please note that the configuration depicted represents a "split axis" press, that is, the floating table 815 and associated loader (not shown) are along one of the dimensions seen near the lower right corner of the figure at reference 823 In the direction of Y-axis 825, push the substrate into and out of the drawing page.

To perform droplet measurements, the printhead assembly 807 is selectively advanced outside a normal printing area to a point where it can be parked in a maintenance station, generally associated with a second Closed environment805. This second environment is optional, but useful in allowing inspection, print head replacement, and other forms of servicing without the need to add vents to the print enclosure 803. To park printhead assembly 807, the assembly is moved to a position that appears generally to the left of the figure and is then Advance vertically to seal the print head assembly 807 in a chamber that serves as the second enclosed environment, as depicted by dashed line location 819. In this "parked" position, droplet measurement system 817 can be controlled (eg, in three dimensions) to selectively move a measurement area simulating a substrate deposition height adjacent any desired nozzle area.

Note that, as mentioned previously, in a typical application it is desirable to keep the manufacturing equipment 801 "online" and in use as much as possible. To this end, rather than performing droplet measurement when device 801 can be used for printing (but for product manufacturing), in one embodiment, measurement and printing are "ping-ponged", that is, each time After a substrate (e.g., 813) is loaded or unloaded, during a period of printing activity, the print head assembly 807 is advanced to a service station and locally calibrated (e.g., for the printing nozzles and/or the printing nozzles). a rolling subset of the waveform), thereby establishing a robust set of measurements for each nozzle in a manner that accumulates a statistical total of measurements, updates to the latest state, and performs maintenance, as previously described. Please note that any of these features may be considered optional and may not be necessary for implementation of the disclosed technology.

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 enclosed chamber is likewise generally designated by reference number 803, while the second enclosed environment for droplet measurement is generally designated by reference number 805. Within the printing enclosure, the substrate to be printed is also generally designated by reference numeral 813, and the support platform used to transport the substrate is generally designated by reference numeral 815. In summary, any xy coordinate system of the substrate is reached by a combination of movements, including movement of the substrate in the x and y dimensions by the support (e.g., using a floating support, as represented by reference numeral 857), and by using a Movement of the "slow axis" x-dimension of one or more print heads 807 of the sliding rod 811 is generally represented by arrow 809. As mentioned previously, floating tables and substrate handling infrastructure are used to move substrates along one or more "rapid axes" during printing as needed. It can be seen that the print head has a plurality of nozzles 865, each nozzle is controlled by a spray pattern derived from a printed image (for example, when the print head moves along the "slow axis" from left to right and from right to Shifting to the left causes printing of rows corresponding to the press grid points. brush); please note that although only a few printing nozzles are depicted in the figure, there are actually hundreds to thousands of such nozzles, arranged in many rows and columns. Printing essentially presents a web area following a plurality of individual columns of printer grid points using relative movement between one or more print heads and the substrate provided in the fast axis (ie, y-axis) direction. It can also selectively rotate or otherwise adjust the print head assembly to change 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 axis legend in Figure 8B). The printing action continues until the entire target area (and any border areas) has been printed with ink as desired, with the vertical component of the depicted transfer direction 857 representing relative printhead assembly/substrate movement. After the necessary amount of ink has been deposited, the substrate is finished, such as by using an ultraviolet (UV) or other curing or hardening process to form a permanent stack from the liquid ink. As mentioned earlier, when substrates are loaded or unloaded for printing, the print head is advanced to a service station and sealed to a second enclosed environment 805. Practically, this second enclosed environment is configured as a subset of the printing enclosed chamber 803 as mentioned above, so that a print head can be replaced without adding ventilation holes to the printing enclosed chamber at all. Within the second enclosed environment 805, a droplet measurement system 817 (visible in the dashed line below the sliding bar 811) is selectively engaged (again, advantageously utilizing, for example, the entirety of the droplet measurement system in one of the enclosures). sexual three-dimensional connection) for measurement as described earlier.

Figure 9 provides a graph illustrating measured drop position relative to the expected position of the drop for each of a number of nozzles. More specifically, the diagram is generally designated by reference numeral 901 and shows a group of approximately 40 nozzles. It should be assumed that graph 901 represents image data, for example, processed as described above with reference to Figures 6A-6C to obtain a measured drop position (meaning, such as position 904) relative to a corresponding expected position (ie, such as position 904). That is, such as position 903). Relative to Figure 9, some features should be noted. First, the nozzles appear to be configured in rows of nozzles that are slightly staggered in position, as shown in diagram 905; this feature allows for extremely precise droplet spacing, for example, when manufacturing tolerances cause the nozzles to be positioned hundreds of microns apart across a span Slight staggering between columns in the scanning direction allows the use of alternating nozzles (e.g., relative to Positioning the nozzle at position 907 corresponding to the nozzle at position 906) allows for extremely tight droplet placement, for example, within 20 microns or less of any predetermined location on a substrate. Second, diagram 901 indirectly emphasizes the benefits provided by positional calibration of a drop measurement system relative to a print head, e.g., the system knowing exactly which nozzle corresponds to position 903 and expected position 904 shows its importance in order to Ability to match any measurement data (and any nozzle qualification or adjustment) to the correct nozzle. Through image processing, the precise position offset of each nozzle can be determined and factored into the influencing factors of nozzle qualification verification and printing planning. Finally, please note again that the use of a transparent film allows imaging not only of deposited droplets but also of the nozzle (e.g., through the transparent film), which facilitates the performance of distance analysis by the software. This is not necessary for all embodiments. For example, by understanding how the image captured through the film corresponds to the position of the nozzle plate, the software can also easily infer the position of the nozzle relative to the captured image, and calculate the position offset based on this. . In the context of Figure 9, reference numeral 904 in one embodiment represents the image nozzle position, where any deviation between measurement position 903 and position 904 represents droplet velocity and/or warpage. Also, while Figure 9 represents droplet position offset relative to a desired droplet position, similar analysis can also be used to measure droplet volume, for example, by converting the droplet color (e.g., grayscale value ), droplet diameter, or other characteristics of the captured image are compared to a standard from which the droplet volume is calculated. Through the use of repeated additional measurements for each nozzle or nozzle-waveform pair, the system can easily establish the distribution of any desired droplet parameters on a per-nozzle or per-nozzle waveform basis.

Figure 10 shows a flow chart 1001 for determining droplet volume from a captured image. Referring to numeral 1003, a captured image representing droplets produced by a nozzle array is first retrieved from the memory. This image is then optionally filtered to segment exactly the droplets of interest (eg, with different color intensities depending on the thickness or concentration of the ink on the deposition medium), reference numeral 1005. Note that these filtered images can be the first, second, third, or other sample of a filtering operation performed to measure a specific parameter from a single image (e.g., other samples can be used to measure droplet velocity , position, nozzle position, etc. Calculate distance, position, offset, etc.). Referring to numeral 1007, any color tint is then processed to relate that tint to ink thickness or density; for example, if the deposited ink has a slightly reddish tint, a "redder" portion of the image will typically represent greater thickness . Please 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 consideration in preferred embodiments. However, this is not necessary for all embodiments, for example if it is known that for example five droplets have been deposited, it may be sufficient to calculate the overall volume and divide it by five. Referring to numeral 1009, the droplet radius is then calculated as described earlier (or the ink coverage is aggregated) and used in conjunction with the derived thickness magnitude to calculate the total deposited ink. Importantly, a transparent film used as a deposition surface ideally holds the deposited ink and therefore 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, a storage criterion specific to the deposited material is retrieved and used with thickness processing, volume calculation 1011, or both to obtain a correct droplet volume estimate. Finally, the measurement data is stored, reference numeral 1013, and any calculated per-nozzle or per-nozzle waveform distributions (eg, mean and deviation) 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 the particular application.

Based on the various technologies and considerations mentioned above, a process can be implemented to quickly mass-produce products with low system cost. By providing fast and repeatable printing technology, it is believed that printing can be substantially improved, for example, reducing the layer-by-layer printing time to a fraction of the time required before using the aforementioned technology. Returning again to the example of a large HD TV display, 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 one hundred and eighty seconds or so. Less time, or even ninety seconds or less, represents substantial process improvement. Improved printing efficiency and quality paves the way for dramatic cost reductions in producing large HD TV displays, resulting in lower costs for the end consumer. As mentioned earlier, the display Manufacturing (especially OLED manufacturing) is an application of the technologies described in this article, which can be applied to a wide range of processes, computers, printers, software, manufacturing equipment and end devices, and are not limited to display panels.

In the foregoing description and accompanying drawings, specific terminology and drawing symbols are used to provide a thorough understanding of the disclosed embodiments. In some instances, these terms and symbols may imply specific details that are not necessary to practice the embodiments. 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, features or characteristics of any embodiment may be combined with any other embodiment, at least to the extent practicable, or may replace equivalent features or characteristics of any other embodiment. Thus, for example, not all features may be shown in every figure. For example, a feature or technique shown in accordance with an embodiment of one figure should be assumed to be selectively employable as in any other figure. One of the elements in the formula or embodiment, or combined with it, even if it is not specifically pointed out in the description. Therefore, the description and drawings should be interpreted as illustrative rather than restrictive.

101:Flowchart

103-123: Steps

Claims (20)

A droplet measurement unit, which includes: a chassis that includes a measurement system for loading a film, an image capture system, and a film rolling motor, wherein the image capture system includes an optical component, and the optical component Moveable relative to the measurement system for capturing images of droplets deposited on the film; and a mechanism within the droplet measurement unit for capturing images of the droplets in the image capture system The droplets are then solidified. The droplet measurement unit of claim 1, wherein the measurement system is coupled to a vacuum system to load the film. 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 system. The droplet measurement unit of claim 1, further comprising: a unit for providing the film from a supply roll to the measurement system and advancing the film from the measurement system to a storage roll, and wherein the A film rolling motor drives at least one of the supply roll and the storage roll. The droplet measurement unit of claim 4, wherein the measurement system is coupled to a vacuum system to load the film. The droplet measurement unit of claim 1, wherein the mechanism for solidifying the droplets includes an ultraviolet light source. The droplet measurement unit of claim 6, further comprising a winch to transport the film to the mechanism for solidifying the droplets. The droplet measurement unit of claim 2, wherein the measurement system defines a plane, and the optical component is movable relative to the measurement system in a direction parallel to the plane. The droplet measurement unit of claim 7, wherein the mechanism for solidifying the droplets Positioned downstream of this winch. The droplet measurement unit of claim 4, wherein the unit further includes a winch adjacent to the measurement system, and the storage drum is adjacent to the mechanism for solidifying the droplets. A droplet measurement unit, which includes: a chassis with a measurement system for loading a film; a film rolling motor for positioning the film along a surface of the measurement system, wherein the The surface defines a plane; a mechanism for solidifying the droplets after capturing images of the droplets deposited on the film with an imaging system; and the imaging system parallel to the plane with respect to the measurement system is movable in one direction. The droplet measurement unit of claim 11, wherein the measurement system is coupled to a vacuum system to load the film. The droplet measurement unit of claim 11, wherein the chassis further includes a winch, the winch is adjacent to the measurement system. The droplet measurement unit of claim 11, wherein the chassis further includes a capstan, the capstan is adjacent to the measurement system, and the mechanism for solidifying the droplets is positioned downstream of the capstan. The droplet measurement unit of claim 11, wherein the mechanism for solidifying the droplets includes an ultraviolet light source. The droplet measurement unit of claim 15, wherein the film is provided by a removable supply roll. The droplet measurement unit of claim 16, further comprising a winch, the winch The film is transported from the measurement system to the mechanism for solidifying the droplets. An inkjet printer comprising: a print head for dispensing liquid droplets; and the droplet measurement unit of claim 1 or 11, wherein the print head is positionable to engage with the droplet measurement unit to measure the liquid droplets distributed by the print head. An inkjet printer includes: a print head for dispensing liquid droplets; and a droplet measurement unit including: a chassis for receiving a droplet on a film A measurement system for loading the film with droplets of liquid, an image capturing system for imaging the droplets on the film, a mechanism for solidifying the droplets after imaging, and a film rolling system A motor, wherein the image capturing system includes an optical component that is movable relative to the measurement system, and wherein the droplet measurement unit is movable in two dimensions relative to the print head. The inkjet printer of claim 19, wherein the droplet measurement unit is moveable relative to the print head in three dimensions.

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