Fast Measurement of Droplet Parameters in Industrial Printing System

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.

1 . (canceled) 
     
     
         2 . A method of fabricating a thin-film layer of an electronic product, the method comprising:
 receiving a substrate into a manufacturing system;   while the substrate is in a printing area of the manufacturing system, printing droplets of a liquid onto the substrate from respective nozzles of one or more printheads of the manufacturing system, the droplets of the liquid to coalesce to form a liquid coat on the substrate, the liquid carrying a film-forming material, wherein there are at least five hundred of the respective nozzles carried by the one or more printheads;   processing the liquid coat to solidify the film-forming material so as to form the thin-film layer therefrom; and   unloading the substrate from the manufacturing system;   wherein the method further comprises calibrating droplets produced by respective ones of the at least five hundred nozzles, in situ within the manufacturing system, for at least one of droplet volume, droplet size, droplet shape or droplet landing location, by
 robotically transporting the one or more printheads to a location within the manufacturing system, outside of the printing area, 
 while the one or more printheads are at the location, using a droplet measurement system to collectively image droplets respectively produced by nozzles in a subset of the at least five hundred respective nozzles and, based on the collective image of the droplets produced by the nozzles in the subset, to calculate the at least one value of droplet volume, droplet shape, droplet size or droplet landing location for droplets produced by each of the nozzles in the subset, and 
 repeating the using of the droplet measurement system to collectively image droplets and to calculate the at least one value in a manner so as to compute the at least one value for each one of the at least five hundred of the respective nozzles carried by the one or more printheads, and 
 robotically transporting the one or more printheads from the location to the printing area for the printing, 
   wherein the manufacturing system performs the printing in a manner dependent on the measurements of the at least one of droplet volume, droplet shape, droplet size or droplet landing location for the at least five hundred nozzles.   
     
     
         3 . The method of  claim 2 , wherein the droplet measurement device is to provide a translucent test substrate having a first side, onto which the droplets produced by the subset are deposited at respective positions on the first side, and wherein the translucent test substrate has a second side, through which the collective image of the droplets is captured by the image capture system. 
     
     
         4 . The method of  claim 3 , wherein the droplet measurement system comprises a chassis that mounts a reel of tape, the tape providing the translucent test substrate, and that mounts a camera and a tape advancement system, wherein the chassis defines a window and wherein tape advancement system is to advance the tape relative to the window such that a first side of the tape is to receive the droplets respectively produced by the nozzles in the subset, and such that the camera is to image the droplets deposited onto the first side of the tape through the window and through a second side of the tape, and wherein the method further comprises robotically transporting the droplet measurement system while the one or more printheads are at the location, without moving the one or more printheads, and advancing the tape relative to the window so as to perform the repeating. 
     
     
         5 . The method of  claim 3 , wherein the at least one value is one of droplet size or droplet volume, for each nozzle of the at least five hundred nozzles, and wherein the image processing system is to compute the one of droplet size or droplet volume by identifying an area each droplet in the image occupies on the first side of the tape, and by computing the at least one value for a corresponding nozzle in the subset in dependence on the identified area. 
     
     
         6 . The method of  claim 2 , wherein the manufacturing system performs the printing in the manner dependent on the measurements by selectively assigning nozzles to print respective ones of the droplets of the liquid onto the substrate in dependence on the measurements. 
     
     
         7 . The method of  claim 2 , wherein the manufacturing system performs the printing in the manner dependent on the measurements by selectively disqualifying nozzles from use in the printing of the droplets of the liquid onto the substrate in dependence on the measurements. 
     
     
         8 . The method of  claim 2 , wherein the droplet measurement system comprises a transport system adapted to move an image capture device of the droplet measurement system in at least two dimensions while the one or more printheads are stationary at the location, so as to robotically reposition the image capture device to image droplets produced by different subsets of the nozzles without requiring relative movement between the one or more printheads and the manufacturing system. 
     
     
         9 . The method of  claim 2 , wherein the manufacturing system comprises a gas enclosure to hold a controlled atmosphere, and wherein the printing of the droplets of the liquid onto the substrate and the calibrating of the droplets using the droplet measurement system are each performed within the gas enclosure and within the controlled atmosphere. 
     
     
         10 . The method of  claim 2 , wherein the manufacturing system comprises at least one of a curing system or a baking system, and wherein the processing of the liquid coat comprises curing or baking the liquid coat, using the at least one of the curing system or the baking system, to solidify the film-forming material relative to the liquid. 
     
     
         11 . The method of  claim 10 , wherein the processing of the liquid coat comprises transporting the substrate from the printing area to a processing area at which the curing or baking is performed, and wherein the repeating is performed, at least in part, when the substrate is at the processing area. 
     
     
         12 . The method of  claim 10 , wherein the electronic product comprises a light-emitting device, and wherein the thin-film layer comprises a light generating layer of the light-emitting device. 
     
     
         13 . A method of fabricating a thin-film layer of electronic products, the method comprising:
 for each substrate in a series of substrates,
 receiving the substrate into a manufacturing system, 
 while the substrate is in a printing area of the manufacturing system, printing droplets of a liquid onto the substrate from respective nozzles of one or more printheads of the manufacturing system, the droplets of the liquid to coalesce to form a liquid coat on the substrate, the liquid carrying a film-forming material, wherein there are at least five hundred of the respective nozzles carried by the one or more printheads, 
 processing the liquid coat to solidify the film-forming material so as to form the thin-film layer therefrom, and 
 unloading the substrate from the manufacturing system; 
   wherein the method further comprises, calibrating droplets produced by respective ones of the at least five hundred nozzles, in situ within the manufacturing system, for at least one of droplet volume, droplet size, droplet shape or droplet landing location, by
 robotically transporting the one or more printheads to a location within the manufacturing system, outside of the printing area, in between printing on respective ones of the substrates in the series, 
 while the one or more printheads are at the location, using a droplet measurement system to collectively image droplets respectively produced by nozzles in a subset of the at least five hundred respective nozzles and, based on the collective image of the droplets produced by the nozzles in the subset, to calculate the at least one value of droplet volume, droplet shape, droplet size or droplet landing location for droplets produced by each of the nozzles in the subset, and 
 robotically transporting the one or more printheads from the location to the printing area for the printing; 
   wherein the method further comprises repeating the using of the droplet measurement system to collectively image droplets and calculate the at least one value in a manner so as to calculate the at least one value for each one of the at least five hundred of the respective nozzles carried by the one or more printheads, and wherein for different successive pairs of the substrates in the series, the nozzles in the subset are changed, in a manner such that the droplet measurement system incrementally measures the at least one of droplet volume, droplet shape, droplet size or droplet landing location for each one of the at least five hundred nozzles in between printing of the droplets onto pairs of the substrates in the series; and   wherein, for each of the substrates, the manufacturing system performs the printing in a manner dependent on the measurements of the at least one of droplet volume, droplet shape, droplet size or droplet landing location for the at least five hundred nozzles.   
     
     
         14 . The method of  claim 13 , wherein the droplet measurement device is to provide a translucent test substrate having a first side, onto which the droplets produced by the subset are deposited at respective positions on the first side, and wherein the translucent test substrate has a second side, through which the collective image of the droplets is captured by the image capture system. 
     
     
         15 . The method of  claim 14 , wherein the droplet measurement system comprises a chassis that mounts a reel of tape, the tape providing the translucent test substrate, that mounts a camera and a tape advancement system, wherein the chassis defines a window and wherein tape advancement system is to advance the tape relative to the window such that a first side of the tape is to receive the droplets respectively produced by the nozzles in the subset, and such that the camera is to image the droplets deposited onto the first side of the tape through the window and through a second side of the tape, and wherein the method further comprises robotically transporting the droplet measurement system while the one or more printheads are at the location, without moving the one or more printheads, and advancing the tape relative to the window so as to perform the repeating. 
     
     
         16 . The method of  claim 15 , wherein the at least one value is one of droplet size or droplet volume, for each nozzle of the at least five hundred nozzles, and wherein the image processing system is to compute the one of droplet size or droplet volume by identifying an area each droplet in the image occupies on the first side of the tape, and by computing the at least one value for a corresponding nozzle in the subset in dependence on the identified area. 
     
     
         17 . The method of  claim 13 , wherein the manufacturing system performs the printing in the manner dependent on the measurements by selectively assigning nozzles to print respective ones of the droplets of the liquid onto the substrate in dependence on the measurements. 
     
     
         18 . The method of  claim 13 , wherein the manufacturing system performs the printing in the manner dependent on the measurements by selectively disqualifying nozzles from use in the printing of the droplets of the liquid onto the substrate in dependence on the measurements. 
     
     
         19 . The method of  claim 13 , wherein the droplet measurement system comprises a transport system adapted to move an image capture device of the droplet measurement system in at least two dimensions while the one or more printheads are stationary at the location, so as to robotically reposition the image capture device to image droplets produced by different subsets of the nozzles without requiring relative movement between the one or more printheads and the manufacturing system. 
     
     
         20 . The method of  claim 13 , wherein the manufacturing system comprises a gas enclosure to hold a controlled atmosphere, and wherein the printing of the droplets of the liquid onto the substrate and the calibrating of the droplets using the droplet measurement system are each performed within the gas enclosure and within the controlled atmosphere. 
     
     
         21 . The method of  claim 13 , wherein the manufacturing system comprises at least one of a curing system or a baking system, and wherein the processing of the liquid coat comprises curing or baking the liquid coat, using the at least one of the curing system or the baking system, to solidify the film-forming material relative to the liquid. 
     
     
         22 . The method of  claim 21 , wherein the processing of the liquid coat comprises transporting the substrate from the printing area to a processing area at which the curing or baking is performed, and wherein the repeating is performed, at least in part, when the substrate is at the processing area. 
     
     
         23 . The method of  claim 21 , wherein the electronic product comprises a light-emitting device, and wherein the thin-film layer comprises a light generating layer of the light-emitting device. 
     
     
         24 . The method of  claim 13 , wherein the thin-film layer is an encapsulation layer that is to encapsulate an electrically-active component of the electronic product. 
     
     
         25 . A method of fabricating a thin-film layer of an electronic product having light-emitting elements, the method comprising:
 receiving a substrate into a manufacturing system;   while the substrate is in a printing area of the manufacturing system and within a controlled gas environment, printing droplets of a liquid onto the substrate from respective nozzles of one or more printheads of the manufacturing system, the droplets of the liquid to coalesce to form a liquid coat on the substrate, the liquid carrying a film-forming material, wherein there are at least five hundred of the respective nozzles carried by the one or more printheads;   processing the liquid coat to solidify the film-forming material so as to form the thin-film layer therefrom; and   unloading the substrate from the manufacturing system;   wherein the method further comprises calibrating droplets produced by respective ones of the at least five hundred nozzles, in situ within the manufacturing system, for at least one of droplet volume, droplet size, droplet shape or droplet landing location, by
 robotically transporting the one or more printheads to a location within the manufacturing system, outside of the printing area, 
 while the one or more printheads are at the location, using a droplet measurement system to collectively image droplets respectively produced by nozzles in a subset of the at least five hundred respective nozzles and, based on the collective image of the droplets produced by the nozzles in the subset, to calculate the at least one value of droplet volume, droplet shape, droplet size or droplet landing location for droplets produced by each of the nozzles in the subset, and 
 repeating the using of the droplet measurement system to collectively image droplets and to calculate the at least one value in a manner so as to compute the at least one value for each one of the at least five hundred of the respective nozzles carried by the one or more printheads, and 
 robotically transporting the one or more printheads from the location to the printing area for the printing; 
   wherein the manufacturing system performs the printing in a manner dependent on the measurements of the at least one of droplet volume, droplet shape, droplet size or droplet landing location for the at least five hundred nozzles; and   wherein the thin-film layer comprises at least one of an encapsulation layer or an electrically-active layer for each of the light emitting elements.