Patent Publication Number: US-2019193436-A1

Title: Gas Enclosure Systems and Methods Utilizing Multi-Zone Circulation and Filtration

Description:
CROSS REFERENCE TO RELATED CASES 
     This application is a continuation of U.S. application Ser. No. 15/839,942, filed Dec. 13, 2017. U.S. application Ser. No. 15/839,942 is a continuation of U.S. application Ser. No. 15/046,381, filed Feb. 2, 2017. U.S. application Ser. No. 15/046,381 is a continuation of Ser. No. 14/801,653, filed Jul. 16, 2015. U.S. application Ser. No. 14/801,653 claims benefit to U.S. Provisional Application No. 62/026,242, filed Jul. 18, 2014 and to U.S. Provisional Application No. 62/034,718, filed Aug. 7, 2014. All applications identified in this section are incorporated herein by reference; each in its entirety. 
    
    
     OVERVIEW 
     Interest in the potential of organic light-emitting diode (OLED) display technology has been driven by OLED display technology attributes that include demonstration of display panels that have highly saturated colors, are high-contrast, ultrathin, fast-responding, and energy efficient. Additionally, a variety of substrate materials, including flexible polymeric materials, can be used in the fabrication of OLED display technology. Though the demonstration of displays for small screen applications, primarily for cell phones, has served to emphasize the potential of the technology, challenges remain in scaling high volume manufacturing across a range of substrate formats in high yield. 
     With respect to scaling of formats, a Gen 5.5 substrate has dimensions of about 130 cm×150 cm and can yield about eight 26″ flat panel displays. In comparison, larger format substrates can include using Gen 7.5 and Gen 8.5 mother glass substrate sizes. A Gen 7.5 mother glass has dimensions of about 195 cm×225 cm, and can be cut into eight 42″ or six 47″ flat panel displays per substrate. The mother glass used in Gen 8.5 is approximately 220 cm×250 cm, and can be cut to six 55″ or eight 46″ flat panel displays per substrate. One indication of the challenges that remain in scaling of OLED display manufacturing to larger formats is that the high-volume manufacture of OLED displays in high yield on substrates larger than Gen 5.5 substrates has proven to be substantially challenging. 
     In principle, an OLED device may be manufactured by the printing of various organic thin films, as well as other materials, on a substrate using an OLED printing system. Such organic materials can be susceptible to damage by oxidation and other chemical processes. Housing an OLED printing system in a fashion that can be scaled for various substrate sizes and can be done in an inert, substantially low-particle printing environment can present a variety of engineering challenges. Manufacturing tools for high throughput large-format substrate printing, for example, such as printing of Gen 7.5 and Gen 8.5 substrates, require substantially large facilities. Accordingly, maintaining a large facility under an inert atmosphere, requiring gas purification to remove reactive atmospheric species, such as water vapor, oxygen and ozone, as well as organic solvent vapors, as well as maintaining a substantially low-particle printing environment, has proven to be significantly challenging. 
     As such, challenges remain in scaling high volume manufacturing of OLED display technology across a range of substrate formats in high yield. Accordingly, there exists a need for various embodiments a gas enclosure system of the present teachings that can house an OLED printing system, in an inert, substantially low-particle environment, and can be readily scaled to provide for fabrication of OLED panels on a variety of substrates sizes and substrate materials. Additionally, various gas enclosure systems of the present teachings can provide for ready access to an OLED printing system from the exterior during processing and ready access to the interior for maintenance with minimal downtime. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the features and advantages of the present disclosure will be obtained by reference to the accompanying drawings, which are intended to illustrate, not limit, the present teachings. 
         FIG. 1A  is a front perspective view of view of a gas enclosure assembly in accordance with various embodiments of the present teachings.  FIG. 1B  depicts an exploded view of various embodiments of a gas enclosure assembly as depicted in  FIG. 1A .  FIG. 1C  depicts an expanded iso perspective view of the printing system depicted in  FIG. 1B . 
         FIG. 2  is an iso perspective view of the placement of substrate proximal to a printing area in a printing system equipped with a camera in accordance with various embodiments of the present teachings. 
         FIG. 3A  and  FIG. 3B  are schematic front cross-section views of various embodiments of gas enclosure assembly and related system components of the present teachings. 
         FIG. 4  is an enlarged schematic front cross-section view of a portion indicated in  FIG. 3B . 
         FIG. 5A  is a schematic top section view of a gas enclosure system in accordance with various embodiments of the present teachings.  FIG. 5B  is a long section schematic of view a gas enclosure system in accordance with various embodiments of the present teachings. 
         FIG. 6  is a schematic front cross-section view of various embodiments of gas enclosure assembly and related system components of the present teachings. 
         FIG. 7A  is a schematic top section view of a gas enclosure system in accordance with various embodiments of the present teachings.  FIG. 7B  is a long section schematic of view a gas enclosure system in accordance with various embodiments of the present teachings. 
         FIG. 8  is a schematic view of various embodiments of gas enclosure assembly and related system components the present teachings. 
         FIG. 9  is a schematic view of various embodiments of gas enclosure assembly and related system components the present teachings. 
         FIG. 10A  and  FIG. 10B  are schematic views of various embodiments of gas enclosure assembly and related system components the present teachings. 
         FIG. 11A ,  FIG. 11B  and  FIG. 11C  are schematic views of various embodiments of gas enclosure assembly and related system components the present teachings. 
         FIG. 12  is a front perspective view of view of a gas enclosure assembly in accordance with various embodiments of the present teachings. 
         FIG. 13A  through  FIG. 13D  depicts the flow communication between a purification system and a gas enclosure system during various operations in accordance with various embodiments of the present teachings. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The present teachings disclose various embodiments of a gas enclosure assembly that can house, for example, an OLED printing system for printing an OLED substrate. Various embodiments of a gas enclosure assembly can be sealably constructed and integrated with various components that provide a gas circulation and filtration system, a particle control system, a gas purification system, and a thermal regulation system and the like to form various embodiments of a gas enclosure system with a controlled environment that can provide an inert gas environment that is substantially low-particle for processes requiring such an environment. Various embodiments of a gas enclosure can have a printing system enclosure and an auxiliary enclosure constructed as a section of a gas enclosure assembly, which can be sealably isolated from the printing system enclosure of a gas enclosure. 
     According to systems and methods of the present teachings, various embodiments of a gas enclosure system can have a gas circulation and filtration system in which gas can be circulated and filtered in various zones. In various embodiments of gas enclosure systems and methods, a gas circulation and filtration system can have a tunnel circulation and filtration zone that provides, for example, but not limited by, a cross-flow of gas across a substrate support apparatus. According to systems and methods of the present teachings, various embodiments of a multi-zone gas circulation and filtration system can have a printing system baffle assembly that is configured to circulate gas across a substrate support apparatus to provide a cross-flow circulation path that is across the direction of substrate travel. In various embodiments of systems and methods of the present teachings, the cross-flow of gas across a substrate support apparatus in a tunnel circulation and filtration zone can be substantially laminar, thereby providing for a low-particle environment throughout a tunnel enclosure section. Additionally, for systems and methods of the present teachings, the cross flow of gas in a printing region proximal to a substrate can remove particles that may be generated by various printing system devices and apparatuses. As such, in addition to providing a low-particle environment throughout a tunnel enclosure section, the cross flow of gas in a printing region proximal to a substrate provides for a low-particle environment in a printing area proximal to a substrate. 
     Various embodiments of a multi-zone circulation and filtration system of the present teachings can have a bridge circulation and filtration zone that can provide circulation and filtration of gas through a printing system bridge and related apparatuses and devices and away from a substrate in a printing region. For various embodiments of a gas enclosure, a tunnel baffle plate can be used to direct gas flow through an opening in the tunnel baffle plate that creates a transition-flow zone into a bridge circulation and filtration zone of gas enclosure. As such, the flow of gas from a transition-flow zone through a bridge circulation and filtration zone provides for moving particles away from a substrate in a printing region, thereby providing for a low-particle printing environment. Various embodiments of a multi-zone circulation and filtration system according to the present teachings can have a bridge baffle plate and a bridge circulation and filtration output plenum with a differ that can circulate gas about a printing system bridge and related apparatuses and devices. As such, the flow of gas from a bridge circulation and filtration output plenum through a bridge circulation and filtration zone provides for moving particles away from a substrate in a printing region, thereby providing for a low-particle printing environment. 
     Accordingly, various embodiments of a multi-zone gas circulation and filtration system of the present teachings can effectively remove both airborne particulate matter in various sections of a gas enclosure, as well as particulate matter generated proximal to a substrate during a printing process. 
     For clearer perspective regarding substrate sizes that can be used in manufacturing of various OLED devises, generations of mother glass substrate sizes have been undergoing evolution for flat panel displays fabricated by other-than OLED printing since about the early 1990&#39;s. The first generation of mother glass substrates, designated as Gen 1, is approximately 30 cm×40 cm, and therefore could produce a 15″ panel. Around the mid-1990&#39;s, the existing technology for producing flat panel displays had evolved to a mother glass substrate size of Gen 3.5, which has dimensions of about 60 cm×72 cm. In comparison, a Gen 5.5 substrate has dimensions of about 130 cm×150 cm. 
     As generations have advanced, mother glass sizes for Gen 7.5 and Gen 8.5 are in production for other-than OLED printing fabrication processes. A Gen 7.5 mother glass has dimensions of about 195 cm×225 cm, and can be cut into eight 42″ or six 47″ flat panels per substrate. The mother glass used in Gen 8.5 is approximately 220×250 cm, and can be cut to six 55″ or eight 46″ flat panels per substrate. The promise of OLED flat panel display for qualities such as truer color, higher contrast, thinness, flexibility, transparency, and energy efficiency have been realized, at the same time that OLED manufacturing is practically limited to G 3.5 and smaller. Currently, OLED printing is believed to be the optimal manufacturing technology to break this limitation and enable OLED panel manufacturing for not only mother glass sizes of Gen 3.5 and smaller, but at the largest mother glass sizes, such as Gen 5.5, Gen 7.5, and Gen 8.5. One of the features of OLED panel display technology includes that a variety of substrate materials can be used, for example, but not limited by, a variety of glass substrate materials, as well as a variety of polymeric substrate materials. In that regard, sizes recited from the terminology arising from the use of glass-based substrates can be applied to substrates of any material suitable for use in OLED printing. 
     Manufacturing tools that in principle can allow for the printing of a variety of substrate sizes that includes large-format substrate sizes, can require substantially large facilities for housing such OLED manufacturing tools. Accordingly, maintaining an entire large facility under an inert atmosphere presents engineering challenges, such as continual purification of a large volume of an inert gas. Various embodiments of a gas enclosure system can have a circulation and filtration system internal a gas enclosure assembly in conjunction with a gas purification system external a gas enclosure that together can provide continuous circulation of a substantially low-particulate inert gas having substantially low levels of reactive species throughout a gas enclosure system. According to the present teachings, an inert gas may be any gas that does not undergo a chemical reaction under a defined set of conditions. Some commonly used non-limiting examples of an inert gas can include nitrogen, any of the noble gases, and any combination thereof. Additionally, providing a large facility that is essentially hermetically sealed to prevent contamination of various reactive atmospheric gases, such as water vapor, oxygen and ozone, as well as organic solvent vapors generated from various printing process poses an engineering challenge. According to the present teachings, an OLED printing facility would maintain levels for each species of various reactive species, including various reactive atmospheric gases, such as water vapor, oxygen and ozone, as well as organic solvent vapors at 100 ppm or lower, for example, at 10 ppm or lower, at 1.0 ppm or lower, or at 0.1 ppm or lower. 
     The need for printing an OLED panel in a facility in which the levels of each of a reactive species should be maintained at targeted low levels can be illustrated in reviewing the information summarized in Table 1. The data summarized on Table 1 resulted from the testing of each of a test coupon comprising organic thin film compositions for each of red, green, and blue, fabricated in a large-pixel, spin-coated device format. Such test coupons are substantially easier to fabricate and test for the purpose of rapid evaluation of various formulations and processes. Though test coupon testing should not be confused with lifetime testing of a printed panel, it can be indicative of the impact of various formulations and processes on lifetime. The results shown in the table below represent variation in the process step in the fabrication of test coupons in which only the spin-coating environment varied for test coupons fabricated in a nitrogen environment where reactive species were less than 1 ppm compared to test coupons similarly fabricated but in air instead of a nitrogen environment. 
     It is evident through the inspection of the data in Table 1 shown below for test coupons fabricated under different processing environments, particularly in the case of red and blue, that printing in an environment that effectively reduces exposure of organic thin film compositions to reactive species may have a substantial impact on the stability of various ELs, and hence on lifetime. The lifetime specification is of particular significance for OLED panel technology, as this correlates directly to display product longevity; a product specification for all panel technologies, which has been challenging for OLED panel technology to meet. In order to provide panels meeting requisite lifetime specifications, levels of each of a reactive species, such as water vapor, oxygen, and ozone, as well as organic solvent vapors, can be maintained at 100 ppm or lower, for example, at 10 ppm or lower, at 1.0 ppm or lower, or at 0.1 ppm or lower with various embodiments of a gas enclosure system of the present teachings. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Impact of inert gas processing on lifetime for OLED panels 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 Process 
                 V 
                 Cd/A 
                 CIE (x, y) 
                 T95 
                 T80 
                 T50 
               
            
           
           
               
               
               
               
            
               
                 Color 
                 Environment 
                 @ 10 mA/cm 2   
                 @ 1000 Cd/m 2   
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Red 
                 Nitrogen 
                 6 
                 9 
                 (0.61, 0.38) 
                 200 
                 1750 
                 10400 
               
               
                   
                 Air 
                 6 
                 8 
                 (0.60, 0.39) 
                 30 
                 700 
                 5600 
               
               
                 Green 
                 Nitrogen 
                 7 
                 66 
                 (0.32, 0.63) 
                 250 
                 3700 
                 32000 
               
               
                   
                 Air 
                 7 
                 61 
                 (0.32, 0.62) 
                 250 
                 2450 
                 19700 
               
               
                 Blue 
                 Nitrogen 
                 4 
                 5 
                 (0.14, 0.10) 
                 150 
                 750 
                 3200 
               
               
                   
                 Air 
                 4 
                 5 
                 (0.14, 0.10) 
                 15 
                 250 
                 1800 
               
               
                   
               
            
           
         
       
     
     In addition to providing an inert environment, maintaining a substantially low-particle environment for OLED printing is of particular importance, as even very small particles can lead to a visible defect on an OLED panel. Particle control in a gas enclosure system can present significant challenges not presented for processes that can be done, for example, in atmospheric conditions under open air, high flow laminar flow filtration hoods. For example, of a manufacturing facility can require a substantial length of various service bundles that can be operatively connected from various systems and assemblies to provide optical, electrical, mechanical, and fluidic connections required to operate, for example, but not limited by, a printing system. Such service bundles used in the operation of a printing system and located proximal to a substrate positioned for printing can be an ongoing source of particulate matter. Additionally, components used in a printing system, such as fans or linear motion systems that use friction bearing, can be particle generating components. Various embodiments of a gas circulation and filtration system of the present teachings can be used in conjunction with particle control components to contain and exhaust particulate matter. Additionally, by using a variety of intrinsically low-particle generating pneumatically operated components, such as, but not limited by, substrate floatation tables, air bearings, and pneumatically operated robots, and the like, a low particle environment for various embodiments of a gas enclosure system can be maintained. 
     Regarding maintaining a substantially low-particle environment, various embodiments of a multi-zone gas circulation and filtration system can be designed to provide a low particle inert gas environment for airborne particulates meeting the standards of International Standards Organization Standard (ISO) 14644-1:1999, “Cleanrooms and associated controlled environments-Part 1: Classification of air cleanliness,” as specified by Class 1 through Class 5. However, controlling airborne particulate matter alone is not sufficient for providing a low-particle environment proximal to a substrate during, for example, but not limited by, a printing process, as particles generated proximal to a substrate during such a process can accumulate on a substrate surface before they can be swept through a gas circulation and filtration system. 
     Accordingly, in conjunction with a gas circulation and filtration system, various embodiments of a gas enclosure system of the present teachings can have a particle control system that can include components that can provide a low-particle zone proximal to a substrate during processing in a printing step. A particle control system for various embodiments of a gas enclosure system of the present teachings can include a multi-zone gas circulation and filtration system, a low-particle-generating X-axis linear bearing system for moving a printhead assembly relative to a substrate, a service bundle housing exhaust system, and a printhead assembly exhaust system. For example, a gas enclosure system can have a gas circulation and filtration system internal a gas enclosure assembly. 
     For systems and methods of the present teachings, various embodiments of a gas enclosure can have gas circulation and filtration in various zones. For example, a tunnel circulation zone of a gas enclosure can provide for the circulation of gas across a substrate support apparatus in a tunnel circulation and filtration zone to provide a cross-flow circulation path that is across the direction of substrate travel. In various embodiments of systems and methods of the present teachings, the cross-flow of gas across a substrate support apparatus in a tunnel circulation zone of a gas enclosure can be substantially laminar. Gas enclosure having a tunnel circulation zone can have a transition-flow zone proximal to a carriage assembly that draws gas away from a substrate located below the carriage assembly. Various embodiments of a gas enclosure system can have a bridge circulation and filtration zone that can provide circulation and filtration of gas about a printing system bridge and related apparatuses and devices, and is in flow communication with the transition-flow zone. Such internal filtration systems can have a plurality of fans for circulation of air, where each fan can be in serial flow communication with a heat exchanger for thermal control of the gas and a filtration unit providing control of circulating particulate matter. For various embodiments of a gas enclosure system, fan filter units can be used to circulate and filter gas, and a heat exchanger can be in flow communication with each fan filter unit. Although a flow of gas generated by a circulation and filtration system need not be laminar, a laminar flow of gas can be used to ensure thorough and complete turnover of gas in the interior. A laminar flow of gas can also be used to minimize turbulence, such turbulence being undesirable as it can cause particles in the environment to collect in such areas of turbulence, preventing the filtration system from removing those particles from the environment. 
     Various embodiments of systems and methods of the present teachings can maintain a substantially low-particle environment providing for an average on-substrate distribution of particles of a particular size range of interest that does not exceed an on-substrate deposition rate specification. An on-substrate deposition rate specification can be set for each of a particle size range of interest of between about 0.1 μm and greater to about 10 μm and greater. In various embodiments systems and methods of the present teachings, an on-substrate particle deposition rate specification can be expressed as a limit of the number of particles deposited per square meter of substrate per minute for each of a target particle size range. 
     Various embodiments of an on-substrate particle deposition rate specification can be readily converted from a limit of the number of particles deposited per square meter of substrate per minute to a limit of the number of particles deposited per substrate per minute for each of a target particle size range. Such a conversion can be readily done through a known relationship between substrates, for example, of a specific generation-sized substrate and the corresponding area for that substrate generation. For example, Table 2 below summarizes aspect ratios and areas for some known generation-sized substrates. It should be understood that a slight variation of aspect ratio and hence size may be seen from manufacturer to manufacturer. However, regardless of such variation, a conversion factor for a specific generation-sized substrate and an area in square meters can be obtained any of a variety of generation-sized substrates. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Correlation between area and substrate size 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Generation ID 
                 X (mm) 
                 Y (mm) 
                 Area (m2) 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Gen 3.0 
                 550 
                 650 
                 0.36 
               
               
                   
                 Gen 3.5 
                 610 
                 720 
                 0.44 
               
               
                   
                 Gen 3.5 
                 620 
                 750 
                 0.47 
               
               
                   
                 Gen 4 
                 680 
                 880 
                 0.60 
               
               
                   
                 Gen 4 
                 730 
                 920 
                 0.67 
               
               
                   
                 Gen 5 
                 1100 
                 1250 
                 1.38 
               
               
                   
                 Gen 5 
                 1100 
                 1300 
                 1.43 
               
               
                   
                 Gen 5.5 
                 1300 
                 1500 
                 1.95 
               
               
                   
                 Gen 6 
                 1500 
                 1850 
                 2.78 
               
               
                   
                 Gen 7.5 
                 1950 
                 2250 
                 4.39 
               
               
                   
                 Gen 8 
                 2160 
                 2400 
                 5.18 
               
               
                   
                 Gen 8 
                 2160 
                 2460 
                 5.31 
               
               
                   
                 Gen 8.5 
                 2200 
                 2500 
                 5.50 
               
               
                   
                 Gen 9 
                 2400 
                 2800 
                 6.72 
               
               
                   
                 Gen 10 
                 2850 
                 3050 
                 8.69 
               
               
                   
                   
               
            
           
         
       
     
     Additionally, an on-substrate particle deposition rate specification expressed as a limit of the number of particles deposited per square meter of substrate per minute can be readily converted to any of a variety of unit time expressions. It will be readily understood that an on-substrate particle deposition rate specification normalized to minutes can be readily converted to any other expression of time through know relationships of time, for example, but not limited by, such as second, hour, day, etc. Additionally, units of time specifically relating to processing can be used. For example, a print cycle can be associated with a unit of time. For various embodiments of a gas enclosure system according to the present teachings a print cycle can be a period of time in which a substrate is moved into a gas enclosure system for printing and then removed from a gas enclosure system after printing is complete. For various embodiments of a gas enclosure system according to the present teachings a print cycle can be a period of time from the initiation of the alignment of a substrate with respect to a printhead assembly to the delivery of a last ejected drop of ink onto the substrate. In the art of processing, total average cycle time or TACT can be an expression of a unit of time for a particular process cycle. According to various embodiments of systems and methods of the present teachings, TACT for a print cycle can be about 30 seconds. For various embodiments of systems and methods of the present teachings, TACT for a print cycle can be about 60 seconds. In various embodiments of systems and methods of the present teachings, TACT for a print cycle can be about 90 seconds. For various embodiments of systems and methods of the present teachings, TACT for a print cycle can be about 120 seconds. In various embodiments of systems and methods of the present teachings, TACT for a print cycle can be about 300 seconds. 
     With respect to airborne particulate matter and particle deposition within a system, a substantial number of variables can impact developing a general model that may adequately compute, for example, an approximation of a value for particle fallout rate on a surface, such as a substrate, for any particular manufacturing system. Variables such as the size of particles, the distribution of particles of particular size; surface area of a substrate and the time of exposure of a substrate within a system can vary depending on various manufacturing systems. For example, the size of particles and the distribution of particles of particular size can be substantially impacted by the source and location of particle-generating components in various manufacturing systems. Calculations based on various embodiments of gas enclosure systems of the present teachings suggest that without various particle control systems of the present teachings, on-substrate deposition of particulate matter per print cycle per square meter of substrate can be between more than about 1 million to more than about 10 million particles for particles in a size range of 0.1 μm and greater. Such calculations suggest that that without various particle control systems of the present teachings, on-substrate deposition of particulate matter per print cycle per square meter of substrate can be between more than about 1000 to about more than about 10,000 particles for particles in a size range of about 2 μm and greater. 
     Various embodiments of a low-particle gas enclosure system of the present teachings can maintain a low-particle environment providing for an average on-substrate particle distribution that meets an on-substrate deposition rate specification of less than or equal to about 100 particles per square meter of substrate per minute for particles greater than or equal to 10 μm in size. Various embodiments of a low-particle gas enclosure system of the present teachings can maintain a low-particle environment providing for an average on-substrate particle distribution that meets an on-substrate deposition rate specification of less than or equal to about 100 particles per square meter of substrate per minute for particles greater than or equal to 5 μm in size. In various embodiments of a gas enclosure system of the present teachings, a low-particle environment can be maintained providing for an average on-substrate particle distribution that meets an on-substrate deposition rate specification of less than or equal to about 100 particles per square meter of substrate per minute for particles greater than or equal to 2 μm in size. In various embodiments of a gas enclosure system of the present teachings, a low-particle environment can be maintained providing for an average on-substrate particle distribution that meets an on-substrate deposition rate specification of less than or equal to about 100 particles per square meter of substrate per minute for particles greater than or equal to 1 μm in size. Various embodiments of a low-particle gas enclosure system of the present teachings can maintain a low-particle environment providing for an average on-substrate particle distribution that meets an on-substrate deposition rate specification of less than or equal to about 1000 particles per square meter of substrate per minute for particles greater than or equal to 0.5 μm in size. For various embodiments of a gas enclosure system of the present teachings, a low-particle environment can be maintained providing for an average on-substrate particle distribution that meets an on-substrate deposition rate specification of less than or equal to about 1000 particles per square meter of substrate per minute for particles greater than or equal to 0.3 μm in size. Various embodiments of a low-particle gas enclosure system of the present teachings can maintain a low-particle environment providing for an average on-substrate particle distribution that meets an on-substrate deposition rate specification of less than or equal to about 1000 particles per square meter of substrate per minute for particles greater than or equal to 0.1 μm in size. 
     It is contemplated that a wide variety of ink formulations can be printed within the inert, substantially low-particle environment of various embodiments of a gas enclosure system of the present teachings. During the manufacture of an OLED display, an OLED pixel can be formed to include an OLED film stack, which can emit light of a specific peak wavelength when a voltage is applied. An OLED film stack structure between an anode and a cathode can include a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EL), an electron transport layer (ETL) and an electron injection layer (EIL). In some embodiments of an OLED film stack structure, an electron transport layer (ETL) can be combined with an electron injection layer (EIL) to form an ETL/EIL layer. According to the present teachings, various ink formulations for an EL for various color pixel EL films of an OLED film stack can be printed using inkjet printing. Additionally, for example, but not limited by, the HIL, HTL, EML, and ETL/EIL layers can have ink formulations that can be printed using inkjet printing. 
     It is further contemplated that an organic encapsulation layer can be printed on an OLED panel using inkjet printing. It is contemplated that an organic encapsulation layer can be printed using inkjet printing, as inkjet printing can provide several advantages. First, a range of vacuum processing operations can be eliminated because such inkjet-based fabrication can be performed at atmospheric pressure. Additionally, during an inkjet printing process, an organic encapsulation layer can be localized to cover portions of an OLED substrate over and proximal to an active region, to effectively encapsulate an active region, including lateral edges of the active region. The targeted patterning using inkjet printing results in eliminating material waste, as well as eliminating additional processing typically required to achieve patterning of an organic layer. An encapsulation ink can comprise a polymer including, for example, but not limited by, an acrylate, methacrylate, urethane, or other material, as well as copolymers and mixtures thereof, which can be cured using thermal processing (e.g. bake), UV exposure, and combinations thereof. As used herein polymer and copolymer can include any form of a polymer component that can be formulated into an ink and cured on a substrate to form an organic encapsulation layer. Such polymeric components can include polymers, and copolymers, as well as precursors thereof, for example, but not limited by, monomers, oligomers, and resins. 
     Various embodiments of a gas enclosure assembly can have various frame members that are constructed to provide contour for a gas enclosure assembly. Various embodiments of a gas enclosure assembly of the present teachings can accommodate an OLED printing system, while optimizing the working space to minimize inert gas volume, and also allowing ready access to an OLED printing system from the exterior during processing. In that regard, various gas enclosure assemblies of the present teachings can have a contoured topology and volume. As will be discussed in more detail subsequently herein, various embodiments of a gas enclosure can be contoured around a printing system base, upon which a substrate support apparatus can be mounted. Further, a gas enclosure can be contoured around a bridge structure used for the X-axis movement of a carriage assembly. As a non-limiting example, various embodiments of a contoured gas enclosure according to the present teachings can have a gas enclosure volume of between about 6 m 3  to about 95 m 3  for housing various embodiments of a printing system capable of printing substrate sizes from Gen 3.5 to Gen 10. By way a further non-limiting example, various embodiments of a contoured gas enclosure according to the present teachings can have a gas enclosure volume of between about 15 m 3  to about 30 m 3  for housing various embodiments of a printing system capable of printing, for example, Gen 5.5 to Gen 8.5 substrate sizes. Such embodiments of a contoured gas enclosure can be between about 30% to about 70% savings in volume in comparison to a non-contoured enclosure having non-contoured dimensions for width, length and height. 
       FIG. 1A  depicts a perspective view of contoured gas enclosure assembly  1000  in accordance with various embodiments of a gas enclosure assembly of the present teachings. Gas enclosure assembly  1000  can include front panel assembly  1200 , middle panel assembly  1300  and rear panel assembly  1400 . Front panel assembly  1200  can include front ceiling panel assembly  1260 , front wall panel assembly  1240 , which can have opening  1242  for receiving a substrate, and front base panel assembly  1220 . Front panel assembly  1200  when assembled can provide a first tunnel enclosure section of a gas enclosure, which is supported by a base. Rear panel assembly  1400  can include rear ceiling panel assembly  1460 , rear wall panel assembly  1440 , which can have opening  1442  for removing a substrate, and rear base panel assembly  1420 . Rear panel assembly  1400  when assembled can provide a second tunnel enclosure section of a gas enclosure, which is supported by a base. Middle panel assembly  1300  can include first middle enclosure panel assembly  1340 , middle wall and ceiling panel assembly  1360  and second middle enclosure panel assembly  1380 , as well as middle base panel assembly  1320 . Middle panel assembly  1300  when assembled can provide a bridge enclosure section of a gas enclosure, which is supported by a base. 
     Additionally, as depicted in  FIG. 1A , middle panel assembly  1300  can include first printhead management system substantially low particle environment, as well as a second printhead management system auxiliary panel assembly (not shown), which provides for an auxiliary gas enclosure. Various embodiments of an auxiliary enclosure constructed as a section of a gas enclosure assembly can be sealably isolated from the working volume of a gas enclosure system. For various embodiments of systems and methods of the present teachings, an auxiliary enclosure can be less than or equal to about 1% of the enclosure volume of a gas enclosure system. In various embodiments of systems and methods of the present teachings, an auxiliary enclosure can be can be less than or equal to about 2% of the enclosure volume of a gas enclosure system. For various embodiments of systems and methods of the present teachings, an auxiliary enclosure can be less than or equal to about 5% of the enclosure volume of a gas enclosure system. In various embodiments of systems and methods of the present teachings, an auxiliary enclosure can be less than or equal to about 10% of the enclosure volume of a gas enclosure system. In various embodiments of systems and methods of the present teachings, an auxiliary enclosure can be less than or equal to about 20% of the enclosure volume of a gas enclosure system. Should the opening of an auxiliary enclosure to an ambient environment containing reactive gases be indicated for performing, for example, a maintenance procedure, isolating an auxiliary enclosure from the working volume of a gas enclosure can prevent contamination of the entire volume of a gas enclosure. Further, given the relatively small volume of an auxiliary enclosure in comparison to the printing system enclosure portion of a gas enclosure, the recovery time for an auxiliary enclosure can take significantly less time than recovery time for an entire printing system enclosure. 
     As depicted in  FIG. 1B , gas enclosure assembly  1000  can include front base panel assembly  1220 , middle base panel assembly  1320 , and rear base panel assembly  1420 , which when fully-constructed form a contiguous base or pan on which OLED printing system  2000  can be mounted. In a similar fashion as described for gas enclosure assembly  100  of  FIG. 1A , the various frame members and panels comprising front panel assembly  1200 , middle panel assembly  1300 , and rear panel assembly  1400  of gas enclosure assembly  1000  can be joined around OLED printing system  2000  to form a printing system enclosure. Front panel assembly  1200  can be contoured around printing system  2000  mounted to form a first tunnel enclosure section of a gas enclosure. Similarly, rear panel assembly  1400  can be contoured around printing system  2000  to form a second tunnel enclosure section of a gas enclosure. Additionally, middle panel assembly  1300  can be contoured around a printing system  2000  to form a bridge enclosure section of a gas enclosure. A fully constructed gas enclosure assembly, such as gas enclosure assembly  1000 , when integrated with various environmental control systems can form various embodiments of a gas enclosure system including various embodiments of an OLED printing system, such as OLED printing system  2000 . According to various embodiments of a gas enclosure system of the present teachings, environmental control of an interior volume defined by a gas enclosure assembly can include control of lighting, for example, by the number and placement of lights of a specific wavelength, control of particulate matter using various embodiments of a particle control system, control of reactive gas species using various embodiments of a gas purification system, and temperature control of a gas enclosure assembly using various embodiments of a thermal regulation system. 
     An OLED inkjet printing system, such as OLED printing system  2000  of  FIG. 1B , shown in expanded view in  FIG. 1C , can be comprised of several devices and apparatuses, which allow the reliable placement of ink drops onto specific locations on a substrate. These devices and apparatuses can include, but are not limited to, a printhead assembly, ink delivery system, a motion system for providing relative motion between a printhead assembly and a substrate, substrate support apparatus, substrate loading and unloading system, and printhead management system. 
     A printhead assembly can include at least one inkjet head, with at least one orifice capable of ejecting droplets of ink at a controlled rate, velocity, and size. The inkjet head is fed by an ink supply system which provides ink to the inkjet head. As shown in an expanded view of  FIG. 1C , OLED inkjet printing system  2000  can have a substrate, such as substrate  2050 , which can be supported by a substrate support apparatus, such as a chuck, for example, but not limited by, a vacuum chuck, a substrate floatation chuck having pressure ports, and a substrate floatation chuck having vacuum and pressure ports. In various embodiments of systems and methods of the present teachings, a substrate support apparatus can be a substrate floatation table. As will be discussed in more detail subsequently herein, substrate floatation table  2200  of  FIG. 1C  can be used for supporting substrate  2050 , and in conjunction with a Y-axis motion system, can be part of a substrate conveyance system providing for the frictionless conveyance of substrate  2050 . A Y-axis motion system of the present teachings can include first Y-axis track  2351  and second Y-axis track  2352 , which can include a gripper system (not shown) for holding a substrate. Y-axis motion can be provided by either a linear air bearing or linear mechanical system. Substrate floatation table  2200  of OLED inkjet printing system  2000  shown in  FIG. 1B  and  FIG. 1C  can define the travel of substrate  2050  through gas enclosure assembly  1000  of  FIG. 1A  during a printing process. 
       FIG. 1C  illustrates generally an example of substrate floatation table  2200  for a printing system  2000  that can include a floating conveyance of a substrate, which can have a porous medium to provide floatation. In the example of  FIG. 1C , a handler or other conveyance can be used to position a substrate  2050  in first region  2201  of a substrate floatation table  2200 , such as located on a conveyor. The conveyer can position the substrate  2050  at a specified location within the printing system such as using either mechanical contact (e.g., using an array of pins, a tray, or a support frame configuration), or using gas cushion to controllably float the substrate  2050  (e.g., an “air bearing” table configuration). A printing region  2202  of the substrate floatation table  2200  can be used to controllably deposit one or more layers on the substrate  2050  during fabrication. The printing region  2202  can also be coupled to an second region  2203  of the substrate floatation table  2200 . The conveyer can extend along the first region  2201 , the printing region  2202 , and the second region  2203  of the substrate floatation table  2200 , and the substrate  2050  can be repositioned as desired for various deposition tasks, or during a single deposition operation. The controlled environments nearby the first region  2201 , the printing region  2202 , and the second region  2203  can be commonly-shared. According to various embodiments of printing system  2000  of  FIG. 1C , first region  2201  can be an input region, and second region  2203  can be an output region. For various embodiments of printing system  2000  of  FIG. 1C , first region  2201  can be both an input and an output region. Further, function referred to in association with regions  2201 ,  2202 , and  2203 , such as input, printing, and output for illustration only. Such regions can be used for other processing steps, such as conveyance of a substrate, or support of a substrate such as during one or more of holding, drying, or thermal treatment of the substrate in one or more other modules. 
     The printing system  2000  of  FIG. 1C  can include one or more printhead devices  2505 , each printhead device having one or more printheads; e.g. nozzle printing, thermal jet or ink-jet type. The one or more printhead devices  2505  can be coupled to or otherwise traversing an overhead carriage, such as first X-axis carriage assembly  2301 . For various embodiments of printing system  2000  of the present teachings, one or more printheads of one or more printhead devices  2505  can be configured to deposit one or more patterned organic layers on the substrate  2050  in a “face up” configuration of the substrate  2050 . Such layers can include one or more of an electron injection or transport layer, a hole injection or transport layer, a blocking layer, or an emission layer, for example. Such materials can provide one or more electrically functional layers. 
     According to the floatation schemes shown in  FIG. 1C , in an example where the substrate  2050  is supported exclusively by the gas cushion, a combination of positive gas pressure and vacuum can be applied through the arrangement of ports or using a distributed porous medium. Such a zone having both pressure and vacuum control can effectively provide a fluidic spring between the conveyor and a substrate. A combination of positive pressure and vacuum control can provide a fluidic spring with bidirectional stiffness. The gap that exists between the substrate (e.g., substrate  2050 ) and a surface can be referred to as the “fly height,” and such a height can be controlled or otherwise established by controlling the positive pressure and vacuum port states. In this manner, the substrate Z-axis height can be carefully controlled in, for example, the printing region  2202 . In some embodiments, mechanical retaining techniques, such as pins or a frame, can be used to restrict lateral translation of the substrate while the substrate is supported by the gas cushion. Such retaining techniques can include using spring loaded structures, such as to reduce the instantaneous forces incident the sides of the substrate while the substrate is being retained; this can be beneficial as a high force impact between a laterally translating substrate and a retaining means can cause substrate chipping or even catastrophic breakage. 
     Elsewhere, as illustrated generally in  FIG. 1C , such as where the fly height need not be controlled precisely, pressure-only floatation zones can be provided, such as along the conveyor in the first or second regions  2201  or  2203 , or elsewhere. A “transition” floatation zone can be provided such as where a ratio of pressure to vacuum nozzles increases or decreases gradually. In an illustrative example, there can be an essentially uniform height between a pressure-vacuum zone, a transition zone, and a pressure only zone, so that within tolerances, the three zones can lie essentially in one plane. A fly height of a substrate over pressure-only zones elsewhere can be greater than the fly height of a substrate over a pressure-vacuum zone, such as in order to allow enough height so that a substrate will not collide with a floatation table in the pressure-only zones. In an illustrative example, an OLED panel substrate can have a fly height of between about 150 micrometers (μ) to about 300μ above pressure-only zones, and then between about 30μ to about 50μ above a pressure-vacuum zone. In an illustrative example, one or more portions of the substrate floatation table  2200  or other fabrication apparatus can include an “air bearing” assembly provided by NewWay® Air Bearings (Aston, Pa., United States of America). 
     A porous medium can be used to establish a distributed pressurized gas cushion for floating conveyance or support of the substrate  2050  during one or more of printing, buffering, drying, or thermal treatment. For example, a porous medium “plate” such as coupled to or included as a portion of a conveyor can provide a “distributed” pressure to support the substrate  2050  in a manner similar to the use of individual gas ports. The use of a distributed pressurized gas cushion without using large gas port apertures can in some instances further improve uniformity and reduce or minimize the formation of mura or other visible defects, such as in those instances where the use of relatively large gas ports to create a gas cushion leads to non-uniformity, in spite of the use of a gas cushion. 
     A porous medium can be obtained such as from Nano TEM Co., Ltd. (Niigata, Japan), such as having physical dimensions specified to occupy an entirety of the substrate  2050 , or specified regions of the substrate such as display regions or regions outside display regions. Such a porous medium can include a pore size specified to provide a desired pressurized gas flow over a specified area, while reducing or eliminating mura or other visible defect formation. 
     Printing requires relative motion between the printhead assembly and the substrate. This is accomplished with a motion system, typically a gantry or split axis XYZ system. Either the printhead assembly can move over a stationary substrate (gantry style), or both the printhead and substrate can move, in the case of a split axis configuration. In another embodiment, a printhead assembly can be substantially stationary; for example, in the X and Y axes, and the substrate can move in the X and Y axes relative to the printheads, with Z axis motion provided either by a substrate support apparatus or by a Z-axis motion system associated with a printhead assembly. As the printheads move relative to the substrate, droplets of ink are ejected at the correct time to be deposited in the desired location on a substrate. A substrate can be inserted and removed from the printer using a substrate loading and unloading system. Depending on the printer configuration, this can be accomplished with a mechanical conveyor, a substrate floatation table with a conveyance assembly, or a substrate transfer robot with end effector. A printhead management system can be comprised of several subsystems which allow for such measurement tasks, such as the checking for nozzle firing, as well as the measurement of drop volume, velocity and trajectory from every nozzle in a printhead, and maintenance tasks, such as wiping or blotting the inkjet nozzle surface of excess ink, priming and purging a printhead by ejecting ink from an ink supply through the printhead and into a waste basin, and replacement of printheads. Given the variety of components that can comprise an OLED printing system, various embodiments of OLED printing system can have a variety of footprints and form factors. 
     With respect to  FIG. 1C , printing system base  2100 , can include first riser  2120  and second riser  2122 , upon which bridge  2130  is mounted. For various embodiments of OLED printing system  2000 , bridge  2130  can support first X-axis carriage assembly  2301  and second X-axis carriage assembly  2302 , which can control the movement of first printhead assembly  2501  and second printhead assembly  2502 , respectively across bridge  2130 . For various embodiments of printing system  2000 , first X-axis carriage assembly  2301  and second X-axis carriage assembly  2302  can utilize a linear air bearing motion system, which are intrinsically low-particle generating. According to various embodiments of a printing system of the present teachings, an X-axis carriage can have a Z-axis moving plate mounted thereupon. In  FIG. 1C , first X-axis carriage assembly  2301  is depicted with first Z-axis moving plate  2310 , while second X-axis carriage assembly  2302  is depicted with second Z-axis moving plate  2312 . Though  FIG. 1C  depicts two carriage assemblies and two printhead assemblies, for various embodiments of OLED inkjet printing system  2000 , there can be a single carriage assembly and a single printhead assembly. For example, either of first printhead assembly  2501  and second printhead assembly  2502  can be mounted on an X,Z-axis carriage assembly, while a camera system for inspecting features of substrate  2050  can be mounted on a second X,Z-axis carriage assembly. Various embodiments of OLED inkjet printing system  2000  can have a single printhead assembly, for example, either of first printhead assembly  2501  and second printhead assembly  2502  can be mounted on an X,Z-axis carriage assembly, while a UV lamp for curing an encapsulation layer printed on substrate  2050  can be mounted on a second X,Z-axis carriage assembly. For various embodiments of OLED inkjet printing system  2000 , there can be a single printhead assembly, for example, either of first printhead assembly  2501  and second printhead assembly  2502 , mounted on an X,Z-axis carriage assembly, while a heat source for curing an encapsulation layer printed on substrate  2050  can be mounted on a second carriage assembly. 
     In  FIG. 1C , each printhead assembly, such as first printhead assembly  2501  and second printhead assembly  2502  of  FIG. 1C , can have a plurality of printheads mounted in at least one printhead device, as depicted in partial view for first printhead assembly  2501 , which depicts a plurality of printhead devices  2505 . A printhead device can include, for example, but not limited by, fluidic and electronic connections to at least one printhead; each printhead having a plurality of nozzles or orifices capable of ejecting ink at a controlled rate, velocity and size. For various embodiments of printing system  2000 , a printhead assembly can include between about 1 to about 60 printhead devices, where each printhead device can have between about 1 to about 30 printheads in each printhead device. A printhead, for example, an industrial inkjet head, can have between about 16 to about 2048 nozzles, which can expel a droplet volume of between about 0.1 pL to about 200 pL. 
     According to various embodiments of a gas enclosure system of the present teachings, given the sheer number of printhead devices and printheads, first printhead management system  2701  and second printhead management system  2702  can be housed in an auxiliary enclosure, which can be isolated from a printing system enclosure during a printing process for performing various measurement and maintenance tasks with little or no interruption to the printing process. As can be seen in  FIG. 1C , first printhead assembly  2501  can be seen positioned relative to first printhead management system  2701  for ready performance of various measurement and maintenance procedures that can be performed by first printhead management system apparatuses  2707 ,  2709  and  2711 . Apparatuses  2707 ,  2709 , and  2011  can be any of a variety of subsystems or modules for performing various printhead management functions. For example apparatuses  2707 ,  2709 , and  2011  can be any of a drop measurement module, a printhead replacement module, a purge basin module, and a blotter module. As depicted in  FIG. 1C , first printhead management system apparatuses  2707 ,  2709  and  2711  and can be mounted on linear rail motion system  2705  for positioning relative to first printhead assembly  2501 . Similarly, second printhead management system  2702 , which can have a similar complement of apparatuses, can have printhead management apparatuses mounted on linear rail motion system  2706  for positioning relative to first printhead assembly  2502 . 
     With respect to various embodiments of a gas enclosure assembly having an auxiliary enclosure that can be closed off from, as well as sealably isolated from a first working volume, for example, a printing system enclosure, reference is made again to  FIG. 1B . As depicted in  FIG. 1C , there can be four isolators on OLED printing system  2000 ; first isolator set  2110  (second not shown on opposing side) and second isolator set  2112  (second not shown on opposing side), which support substrate floatation table  2200  of OLED printing system  2000 . For gas enclosure assembly  1000  of  FIG. 1B , first isolator set  2110  and second isolator set  2112  can be mounted in each of a respective isolator well panel, such as first isolator wall panel  1325  and second isolator wall panel  1327  of middle base panel assembly  1320 . For gas enclosure assembly  1000  of  FIG. 1B , middle base assembly  1320  can include first auxiliary enclosure  1330 , as well as second auxiliary enclosure  1370 .  FIG. 1B  of gas enclosure assembly  1000  depicts first auxiliary enclosure  1330  that can include first back wall panel assembly  1338 . Similarly, also depicted is second auxiliary enclosure  1370  that can include second back wall panel assembly  1378 . First back wall panel assembly  1338  of first auxiliary enclosure  1330  can be constructed in a similar fashion as shown for second back wall panel assembly  1378 . Second back wall panel assembly  1378  of second auxiliary enclosure  1370  can be constructed from second back wall frame assembly  1378  having second seal-support panel  1375  sealably mounted to second back wall frame assembly  1378 . Second seal-support panel  1375  can have second passage  1365 , which is proximal to a second end of base  2100  (not shown). Second seal  1367  can be mounted on second seal-support panel  1375  around second passage  1365 . A first seal can be similarly positioned and mounted around a first passage for first auxiliary enclosure  1330 . Each passage in auxiliary panel assembly  1330  and auxiliary panel assembly  1370  can accommodate having each maintenance system platform, such as first and second maintenance system platforms  2703  and  2704  of  FIG. 1C  pass through the passages. As will be discussed in more detail subsequently herein, in order to sealably isolate auxiliary panel assembly  1330  and auxiliary panel assembly  1370  the passages, such as second passage  1365  of  FIG. 1B  must be sealable. It is contemplated that various seals, such as an inflatable seal, a bellows seal and a lip seal can be used for sealing a passage, such as second passage  1365  of  FIG. 1B , around a maintenance platform affixed to a printing system base. 
     First auxiliary enclosure  1330  and second auxiliary enclosure  1370  can include first printhead assembly opening  1342  of first floor panel assembly  1341  and second printhead assembly opening  1382  of second floor panel assembly  1381 ; respectively. First floor panel assembly  1341  is depicted in  FIG. 1B  as part of first middle enclosure panel assembly  1340  of middle panel assembly  1300 . First floor panel assembly  1341  is a panel assembly in common with both first middle enclosure panel assembly  1340  and first auxiliary enclosure  1330 . Second floor panel assembly  1381  is depicted in  FIG. 1B  as part of second middle enclosure panel assembly  1380  of middle panel assembly  1300 . Second floor panel assembly  1381  is a panel assembly in common with both second middle enclosure panel assembly  1380  and second auxiliary enclosure  1370 . 
     As previously discussed herein, first printhead assembly  2501  can be housed in first printhead assembly enclosure  2503 , and second printhead assembly  2502  can be housed in second printhead assembly enclosure  2504 . According to systems and methods of the present teachings, first printhead assembly enclosure  2503  and second printhead assembly enclosure  2504  can have an opening at the bottom that can have a rim (not shown), so that various printhead assemblies can be positioned for printing during a printing process. Additionally, the portions of first printhead assembly enclosure  2503  and second printhead assembly enclosure  2504  forming a housing can be constructed as previously described for various panel assemblies, so that the frame assembly members and panels are capable of providing an hermetically-sealed enclosure. 
     A compressible gasket which can additionally be used for the hermetic sealing of various frame members, can be affixed around each of first printhead assembly opening  1342  and second printhead assembly opening  1382 , or alternatively around the rim of first printhead assembly enclosure  2503  and second printhead assembly enclosure  2504 . 
     According to the present teachings, compressible gasket material can be selected from, for example, but not limited by, any in the class of closed-cell polymeric materials, also referred to in the art as expanded rubber materials or expanded polymer materials. Briefly, a closed-cell polymer is prepared in a fashion whereby gas is enclosed in discrete cells; where each discrete cell is enclosed by the polymeric material. Properties of compressible closed-cell polymeric gasket materials that are desirable for use in gas-tight sealing of frame and panel components include, but are not limited by, that they are robust to chemical attack over a wide range of chemical species, possess excellent moisture-barrier properties, are resilient over a broad temperature range, and they are resistant to a permanent compression set. In general, compared to open-cell-structured polymeric materials, closed-cell polymeric materials have higher dimensional stability, lower moisture absorption coefficients, and higher strength. Various types of polymeric materials from which closed-cell polymeric materials can be made include, for example, but not limited by, silicone, neoprene, ethylene-propylene-diene terpolymer (EPT); polymers and composites made using ethylene-propylene-diene-monomer (EPDM), vinyl nitrile, styrene-butadiene rubber (SBR), and various copolymers and blends thereof. 
     In addition to close-cell compressible gasket materials, another example of a class of compressible gasket material having desired attributes for use in constructing embodiments of a gas enclosure assembly according to the present teachings includes the class of hollow-extruded compressible gasket materials. Hollow-extruded gasket materials as a class of materials have the desirable attributes, including, but not limited by, that they are robust to chemical attack over a wide range of chemical species, possess excellent moisture-barrier properties, are resilient over a broad temperature range, and they are resistant to a permanent compression set. Such hollow-extruded compressible gasket materials can come in a wide variety of form factors, such as for example, but not limited by, U-cell, D-cell, square-cell, rectangular-cell, as well as any of a variety of custom form factor hollow-extruded gasket materials. Various hollow-extruded gasket materials can be fabricated from polymeric materials that are used for closed-cell compressible gasket fabrication. For example, but not limited by, various embodiments of hollow-extruded gaskets can be fabricated from silicone, neoprene, ethylene-propylene-diene terpolymer (EPT); polymers and composites made using ethylene-propylene-diene-monomer (EPDM), vinyl nitrile, styrene-butadiene rubber (SBR), and various copolymers and blends thereof. Compression of such hollow cell gasket materials should not exceed about 50% deflection in order to maintain the desired attributes. 
     As depicted in  FIG. 1B , first printhead assembly docking gasket  1345  and second printhead assembly docking gasket  1385  can be affixed around first printhead assembly opening  1342  and second printhead assembly opening  1382 , respectively. During various printhead measurement and maintenance procedures, first printhead assembly  2501  and second printhead assembly  2502  can be positioned by first X,Z-axis carriage assembly  2301  and second X,Z-axis carriage assembly  2302 , respectively, over first printhead assembly opening  1342  of first floor panel assembly  1341  and second printhead assembly opening  1382  of second floor panel assembly  1381 , respectively. In that regard, for various printhead measurement and maintenance procedures, first printhead assembly  2501  and second printhead assembly  2502  can be positioned over first printhead assembly opening  1342  of first floor panel assembly  1341  and second printhead assembly opening  1382  of second floor panel assembly  1381 , respectively, without covering or sealing first printhead assembly opening  1342  and second printhead assembly opening  1382 . First X,Z-axis carriage assembly  2301  and second X,Z-axis carriage assembly  2302  can dock first printhead assembly enclosure  2503  and second printhead assembly enclosure  2504 , respectively, with first auxiliary enclosure  1330  and second auxiliary enclosure  1370 , respectively. In various printhead measurement and maintenance procedures, such docking may effectively close first printhead assembly opening  1342  and second printhead assembly opening  1382  without the need for sealing first printhead assembly opening  1342  and second printhead assembly opening  1382 . For various printhead measurement and maintenance procedures, the docking can include the formation of a gasket seal between each of the printhead assembly enclosures and the printhead management system panel assemblies. In conjunction with sealably closing passages, such as second passage  1365  and a complementary first passage of  FIG. 1B , when first printhead assembly enclosure  2503  and second printhead assembly enclosure  2504  are docked with first auxiliary enclosure  1330  and second auxiliary enclosure  1370  to sealably close first printhead assembly opening  1342  and second printhead assembly opening  1382 , the combined structures so formed are hermetically sealed. 
     Additionally, according to the present teachings, an auxiliary enclosure can be isolated from, for example, another interior enclosure volume, such as the printing system enclosure, as well as the exterior of a gas enclosure assembly, by using a structural closure to sealably close a passageway, such as first printhead assembly opening  1342  and second printhead assembly opening  1382  of  FIG. 1B . According to the present teachings, a structural closure can include a variety of sealable coverings for an opening or passageway; such opening or passageway including non-limiting examples of an enclosure panel opening or passageway. According to systems and methods of the present teachings, a gate can be any structural closure that can be used to reversibly cover or reversibly sealably close any opening or passageway using pneumatic, hydraulic, electrical, or manual actuation. As such, first printhead assembly opening  1342  and second printhead assembly opening  1382  of  FIG. 1B  can be reversibly covered or reversibly sealably closed using a gate. 
     In the expanded view of OLED printing system  2000  of  FIG. 1C , various embodiments of a printing system can include substrate floatation table  2200 , supported by substrate floatation table base  2220 . Substrate floatation table base  2220  can be mounted on printing system base  2100 . Substrate floatation table  2200  of OLED printing system can support substrate  2050 , as well as defining the travel over which substrate  2050  can be moved through gas enclosure assembly  1000  during the printing of an OLED substrate. A Y-axis motion system of the present teachings can include first Y-axis track  2351  and second Y-axis track  2352 , which can include a gripper system (not shown) for holding a substrate. Y-axis motion can be provided by either a linear air bearing or linear mechanical system. In that regard, in conjunction with a motion system; as depicted in  FIG. 1C , a Y-axis motion system, substrate floatation table  2200  can provide frictionless conveyance of substrate  2050  through a printing system. 
     In reference to  FIG. 2 , printing system  2001  can have all of the elements previously described for printing system  2000  of  FIG. 1C . For example, but not limited by, printing system  2001  of  FIG. 2  can have service bundle housing exhaust system  2400  for containing and exhausting particles generated from a service bundle. Service bundle housing exhaust system  2400  of printing system  2001  can include service bundle housing  2410 , which can house a service bundle. According to the present teachings, a service bundle can be operatively connected to a printing system to provide various optical, electrical, mechanical and fluidic connections required to operate various devices and apparatuses in a gas enclosure system, for example, but not limited by, various devices and apparatuses associated with a printing system. A positive flow differential through service bundle housing exhaust system  2400  can ensure that particles generated by a service bundle in service bundle housing  2410  can be directed into service bundle housing exhaust plenum  2420  and then into a gas circulation and filtration system through service bundle housing exhaust plenum first duct  2422  and service bundle housing exhaust plenum second duct  2424 . Printing system  2001  of  FIG. 2  can have substrate support apparatus  2250  for supporting substrate  2050 , which can be positioned with precision in the Y-axis direction using Y-axis positioning system  2355 . Both substrate support apparatus  2250  and Y-axis positioning system  2355  are supported by printing system base  2101 . Substrate support apparatus  2250  can be mounted on Y-axis motion assembly  2355  and can be moved on rail system  2360  using, for example, but not limited by, a linear bearing system; either utilizing mechanical bearings or air bearings. For various embodiments of gas enclosure systems, an air bearing motion system helps facilitation frictionless conveyance in the Y-axis direction for a substrate placed on substrate support apparatus  2250 . Y-axis motion system  2355  can also optionally use dual rail motion, once again, provided by a linear air bearing motion system or a linear mechanical bearing motion system. 
     Regarding motion systems supporting various carriage assemblies, printing system  2001  of  FIG. 2  can have first X-axis carriage assembly  2300 A that is depicted having printhead assembly  2500  mounted thereupon and second X-axis carriage assembly  2300 B that is depicted having camera assembly  2550  mounted thereupon. Substrate  2050 , which is on substrate support apparatus  2250 , can be located in various positions proximal to bridge  2130 , for example, during a printing process. Substrate support apparatus  2250  can be mounted on printing system base  2101 . In  FIG. 2 , printing system  2001  can have first X-axis carriage assembly  2300 A and second X-axis carriage assembly  2300 B mounted on bridge  2130 . First X-axis carriage assembly  2300 A can also include first Z-axis moving plate  2310 A for the Z-axis positioning of printhead assembly  2500 , while second X-axis carriage assembly  2300 B can have second Z-axis moving plate  2310 B for the Z-axis positioning of camera assembly  2550 . In that regard, various embodiments of carriage assemblies  2300 A and  2300 B can provide precision X,Z positioning with respect to a substrate positioned on substrate support  2250  for printhead assembly  2500  and camera assembly  2550 , respectively. For various embodiments of printing system  2004 , first X-axis carriage assembly  2300 A and second X-axis carriage assembly  2300 B can utilize a linear air bearing motion system, which is intrinsically low-particle generating. 
     Camera assembly  2550  of  FIG. 2  can be a high-speed, high-resolution camera. A camera assembly  2550  can include camera  2552 , camera mount assembly  2554  and lens assembly  2556 . Camera assembly  2550  can be mounted to motion system  2300 B on Z-axis moving plate  2310 B, via camera mount assembly  2556 . Camera  2552  can be any image sensor device that converts an optical image into an electronic signal, such as by way of non-limiting example, a charge-coupled device (CCD), a complementary metal-oxide-semiconductor (CMOS) device or N-type metal-oxide-semiconductor (NMOS) device. Various image sensor devices can be configured as an array of sensors for an area scan camera, or a single row of sensors, for a line scan camera. Camera assembly  2550  can be connected to image processing system that can include, for example, a computer for storing, processing, and providing results. As previously discussed herein for printing system  2001  of  FIG. 2 , Z-axis moving plate  2310 B can controllably adjust the Z-axis position of camera assembly  2550  relative to substrate  2050 . During various processes, such as for example, printing and data collection, substrate  2050  can be controllably positioned relative to the camera assembly  2550  using the X-axis motion system  2300 B and Y-axis motion system  2355 . 
     Accordingly, the split axis motion system of  FIG. 2  can provide precise positioning of the camera assembly  2550  and substrate  2050  relative to one another in three dimensions in order to capture image data on any part of the substrate  2050  at any desired focus and/or height. Moreover, precision XYZ motion of a camera relative to a substrate can be done for either area scanning or line scanning processes. As previously discussed herein, other motion systems, such as a gantry motion system, can also be used to provide precision movement in three dimensions between, for example, a printhead assembly and/or a camera assembly, relative to a substrate. Additionally, lighting can be mounted in various positions; either on an X-axis motion system or on a substrate support apparatus proximal to a substrate, and combinations thereof. In that regard, lighting can be positioned according to performing various lightfield and darkfield analyses, and combinations thereof. Various embodiments of a motion system can position camera assembly  2550  relative to substrate  2050  using a continuous or a stepped motion or a combination thereof to capture a series of one or more images of the surface of substrate  2050 . Each image can encompass an area associated with one or more pixel wells, associated electronic circuitry components, pathways and connectors of an OLED substrate. By using image processing, images of particles can be obtained, and size and number of particles of a specific size determined. In various embodiments of systems and methods of the present teachings, a line scan camera having about 8192 pixels, with a working height of about 190 mm, and capable of scanning at about 34 kHz can be used. Additionally, more than one camera can be mounted on an X-axis carriage assembly for various embodiments of a printing system camera assembly, where each camera can have different specifications regarding field of view and resolution. For example, one camera can be a line scan camera for in situ particle inspection, while a second camera can be for regular navigation of a substrate in a gas enclosure system. Such a camera useful for regular navigation can be an area scan camera having a field of view in the range of about 5.4 mm×4 mm with a magnification of about 0.9× to about 10.6 mm×8 mm with a magnification of about 0.45×. In still other embodiments, one camera can be a line scan camera for in situ particle inspection, while a second camera can be for precise navigation of a substrate in a gas enclosure system, for example, for substrate alignment. Such a camera can be useful for precise navigation can be an area scan camera having a field of view of about 0.7 mm×0.5 mm with a magnification of about 7.2×. 
     With respect to in situ inspection of an OLED substrate, various embodiments of a printing system camera assembly, such as camera assembly  2550  of printing system  2001  depicted in  FIG. 2 , can be used to inspect a panel without significant impact to total average cycle time (TACT). For example, a Gen 8.5 substrate can be scanned for on-substrate particulate matter in less than 70 seconds. In addition to in situ inspection of OLED substrate, a printing system camera assembly can be used for a system validation study by using a test substrate to determine whether or not a sufficiently low particle environment for a gas enclosure system can be verified prior to using the gas enclosure system for a printing process. 
     Various embodiments of a gas enclosure system can have a gas circulation and filtration system in which gas can be circulated and filtered in various zones. In various embodiments of gas enclosure systems and methods of the present teachings, a gas circulation and filtration system can have a tunnel baffle plate that directs the circulation of filtered gas through an opening that creates a transition-flow zone through which gas can flow into a bridge circulation and filtration zone. A tunnel circulation and filtration system can provide for the cross-flow of gas across a substrate support apparatus. In various embodiments of systems and methods of the present teachings, the cross-flow of gas across a substrate support apparatus in a tunnel circulation and filtration zone can be substantially laminar. A gas enclosure system having a tunnel circulation and filtration zone can have a transition-flow zone proximal to a carriage assembly that draws gas away from a substrate located below the carriage assembly. The gas drawn into the transition flow zone can be drawn through an opening in a tunnel baffle plate. Various embodiments of a gas enclosure system can have a bridge circulation and filtration system that can provide circulation and filtration of gas about a printing system bridge and related apparatuses and devices, and is in flow communication with the transition-flow zone. Various embodiments of a gas circulation and filtration system of the present teachings can effectively remove both airborne particulate matter, as well as particulate matter generated proximal to a substrate during a printing process. 
       FIG. 3A  and  FIG. 3B  are schematic front cross-section views of gas enclosure system  500 A, which depicts a cross section of a first tunnel enclosure section  1200  that illustrate generally tunnel circulation and filtration system  1500 . Additionally, for perspective and context, features as described for various embodiments of gas enclosure  1000  of  FIG. 1A , as well as printing system  2000  of  FIG. 1B  and  FIG. 1C  are depicted in phantom view through a section of bridge enclosure section  1300 . Printing system  2002 , which can be housed in gas enclosure  1002 , can have printing system base  2100 , which can be supported by at least two sets of isolators such as isolator set  2110  that includes isolators  2110 A and  2110 B of  FIG. 3A  and  FIG. 3B . A Y-axis motion system can be mounted on printing system base  2100  and can include Y-axis track  2350 , supported by Y-axis track support  2355 . Substrate  2050  can be floatingly supported by substrate floatation table  2200 . Printing system base  2100  can support first riser  2120  and second riser  2122 , upon which bridge  2130  can be mounted. Printing system bridge  2130  can support first X-axis carriage assembly  2301 , upon which printhead assembly  2500  can be mounted, and second X-axis carriage assembly  2302 , upon which camera assembly  2550  can be mounted. 
     Additionally, gas enclosure system  500 A can have auxiliary enclosure  1330 , depicted in phantom view, which can enclose printhead management system  2701 . Printing system  2000  of  FIG. 1B  depicts a gas enclosure having first auxiliary enclosure  1330  and second auxiliary enclosure  1370 , while in  FIG. 3A  and  FIG. 3B , auxiliary enclosure  1330  is indicated. As such, various embodiments of systems and methods of the present teachings can have a gas enclosure with one auxiliary enclosure. In various embodiments of systems and methods of the present teachings, a gas enclosure can have two auxiliary enclosures. Auxiliary enclosure  1330  can be in flow communication with the printing system enclosure of gas enclosure system  500 A through printhead assembly opening  1342 , and can be sealably isolated from the remaining volume of gas enclosure  1002 , by way of non-limiting example, by docking first printhead assembly  2500  onto first printhead assembly docking gasket  1345 . As will be discussed subsequently in more detail herein, for various embodiments of a multi-zone gas circulation and filtration system of the present teachings, tunnel baffle plate  2150 , shown partially in phantom view in  FIG. 3A  and  FIG. 3B , can be mounted horizontally in a bridge enclosure section of a gas enclosure. 
     As depicted in the schematic front cross-section view of  FIG. 3A  and  FIG. 3B , various embodiments of tunnel circulation and filtration system  1500  can include inlet baffle  2140 , which can include inlet baffle support  2142 . Inlet baffle  2140 , in conjunction with tunnel enclosure  1200 , can direct the flow of gas across floatation table  2200 . Tunnel circulation and filtration system  1500  can include gas intake housing  1510 , in which fan  1520 , heat exchanger  1530 , and filter unit  1540  can be mounted in series. Filter unit  1540  can have tunnel circulation and filtration diffuser  1545  in series with filter unit  1540 , as depicted in  FIG. 3A  and  FIG. 3B . In various embodiments, tunnel circulation and filtration diffuser  1545  can be a perforated metallic plate for creating a controlled distribution of flow. Various embodiments of tunnel circulation and filtration diffuser  1545  can be a filtration material having, for example, but not limited by, a porous structure for creating a controlled distribution of flow. For various embodiments of tunnel circulation and filtration diffuser  1545 , gas flowing through the diffuser can provide for a desired controlled pressure drop, which can result in a controlled flow on an exit side of a diffuser. For example, a diffuser can be designed to offset an uneven flow profile entering a flow-directing structure, such as a duct, a baffle or a plenum, leading to uniform flow on an exit side of a diffuser. Additionally, various embodiments of a diffuser according to the present teachings can be designed for a specifically controlled non-uniform flow profile on an exit side of a diffuser. 
     For various embodiments of tunnel circulation and filtration system  1500 , fan  1520  and filter unit  1540  can be combined into a fan filter unit. Various embodiments of a tunnel circulation and filtration zone can include outlet baffle  2141 , which can include outlet baffle support  2143 . Outlet baffle  2141 , in conjunction with tunnel enclosure  1200 , can direct the flow of gas in a downward direction to be circulated across floatation table  2200  and around a portion of a printing system housed in a first tunnel enclosure and second tunnel enclosure section (see also  FIG. 1B ), thereby providing a cross-flow path in a first tunnel enclosure and second tunnel enclosure section. In that regard, various embodiments of systems and methods of the present teachings can have a first tunnel circulation and filtration zone, as well as a second tunnel circulation and filtration zone. Various embodiments of tunnel circulation and filtration system  1500  can provide filtered gas that circulates across the tunnel zone of a gas enclosure system. As depicted in the cross-section view of  FIG. 3A  and  FIG. 3B , various embodiments of a tunnel circulation and filtration system  1500  direct inert gas across substrate  2050 . For gas enclosure system  500 A, inlet baffle  2140  and outlet baffle  2141 , in conjunction with first tunnel enclosure section  1200  can be used to direct the flow of filtered gas laterally, so that gas is circulated in a cross-flow path through gas enclosure system  500 A. 
     In various embodiments of systems and methods of the present teachings, tunnel circulation and filtration system  1500  of  FIG. 3A  and  FIG. 3B  can provide circulation and filtration for both the first tunnel enclosure section, as well as the second tunnel enclosure section. According to various embodiments of systems and methods of the present teachings, a second tunnel circulation and filtration system having the components described for tunnel circulation and filtration system  1500  of first tunnel enclosure section  1200  of  FIG. 3A  and  FIG. 3B  can be provided for a second tunnel enclosure section, such as second tunnel enclosure section  1400  of  FIG. 1A . 
     As will be discussed in more detail subsequently herein, gas enclosure system  500 A can be in flow communication with a gas enclosure purification system. As depicted in  FIG. 3A , gas purification first outlet line  3131 A can provide flow communication between gas enclosure system  500 A and a gas purification system. Similarly, gas purification inlet line  3133  can be a return line bringing purified inert gas to gas enclosure system  500 A from a gas purification system. For example, during a printing process, gas flowing into auxiliary enclosure  1330  through first printhead assembly opening  1342  of  FIG. 3A  can be cycled to a gas purification system from gas purification first outlet line  3131 A and purified inert gas can be directed back into gas enclosure  1002  through gas purification inlet line  3133 . During such a process, gas purification second outlet line  3131 B can be isolated from flow communication with a purification system, for example, by use of a valve (not shown) in a closed position. As shown in  FIG. 3B , first printhead assembly opening  1342  can be constructed as a sealable section of gas enclosure assembly, for example, by the positioning of first printhead assembly  2500  onto first printhead assembly docking gasket  1345 . According to systems and methods of the present teachings, an auxiliary enclosure can be sealable isolated from a printing system enclosure, and can be opened to an environment external a gas enclosure assembly. For example, while performing a maintenance procedure, auxiliary enclosure  1300  can be opened to the environment, as depicted in  FIG. 3B , without exposing the remaining volume of gas enclosure  1002  to the external environment. As depicted in  FIG. 3B , during such a process, gas purification second outlet line  3131 B would be in flow communication with a purification system, and purified inert gas can be directed back into gas enclosure  1002  through gas purification inlet line  3133 . During such a procedure, gas purification first outlet line  3131 A can be isolated from flow communication with a purification system, for example, by use of a valve (not shown) in a closed position. 
     As indicated in  FIG. 3B ,  FIG. 4  is an enlarged view of a section of printing system  2002 , which depicts filter unit  1540  of first tunnel circulation and filtration system  1500  X under bridge  2130  proximal to substrate  2050 . Substrate  2050  is depicted in  FIG. 4  as floatingly supported by floatation table  2200 . First X-axis carriage assembly  2301 , which has at least one printhead assembly, is controllably positioned in X-axis movement relative to substrate  2050  using a precision movement system. Various components essential to the printing system operation, for example, a service bundle are located proximal to substrate  2050  positioned for printing and can be an ongoing source of particulate matter. As shown in  FIG. 4 , inlet baffle  2140  in combination with first tunnel enclosure section  1200 , can be used to direct a filtered gas stream over substrate  2050 , indicated as substrate cross flow circulation path  10 . Substrate cross flow circulation path  10  as depicted in  FIG. 4  has cross-sectional dimensions X in the horizontal direction defined by X 1  and X 2  and Y in the vertical direction defined by Y 1  and Y 2 . The flow velocity of a circulation and filtration system, such as circulation and filtration system  1500  (see  FIG. 3A ), is set in accordance with the longest horizontal dimension of substrate cross flow circulation path  10 , so that a particle entering the flow stream at about Y 1  will be swept through substrate cross flow circulation path  10  and thereby will not make contact with substrate  2050 . 
     The data in Table 3, shown below, summarizes a limit particle size that can be swept through substrate cross flow circulation path  10  of  FIG. 4 . The calculations were made in consideration of the longest horizontal dimension of each generation substrate size, as well as a range of flow rates from 0.1 to 1 m/s, and additionally in consideration of variation of densities of particles in the range of 1000-9000 kg/m 3 . The upper limit of a particle size; reported as diameter in microns [ ], which includes the value of a diameter reported in Table 3 (i. e. ≤), was determined in consideration of two cases bounded by: 1) the lowest flow rate of 0.1 m/s and highest particle density of a particle of 9000 kg/m 3  and 2) the highest flow rate of 1 m/s and lowest density of a particle of 1000 kg/m 3 . In that regard, the diameters reported represent a value in between those two bounds. The trend of the data indicate that as the longest horizontal dimension of substrate increases under the condition of fairly constant flow velocity, the average limit diameter of a particle that can be effectively swept through cross flow circulation path  10  decreases. However, the smallest particle size reported is for the longest cross flow circulation path for a Gen 10 substrate, and is substantially larger than particle sizes of interest. Accordingly, the summary of calculations presented in Table 3 demonstrate the effectiveness of various embodiments of systems and methods of the present teachings that utilize cross flow for preventing particles from contaminating a substrate surface during processing. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Limit of particle size that can be swept by cross flow. 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                   
                   
                 Limit Particle Size: 
               
               
                 Generation ID 
                 X (mm) 
                 Y (mm) 
                 Area (m 2 ) 
                 Diameter ≤ μ [microns] 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Gen 3.0 
                 550 
                 650 
                 0.36 
                 42 
               
               
                 Gen 3.5 
                 610 
                 720 
                 0.44 
                 40 
               
               
                 Gen 3.5 
                 620 
                 750 
                 0.47 
                 40 
               
               
                 Gen 4 
                 680 
                 880 
                 0.6 
                 38 
               
               
                 Gen 4 
                 730 
                 920 
                 0.67 
                 37 
               
               
                 Gen 5 
                 1100 
                 1250 
                 1.38 
                 30 
               
               
                 Gen 5 
                 1100 
                 1300 
                 1.43 
                 30 
               
               
                 Gen 5.5 
                 1300 
                 1500 
                 1.95 
                 28 
               
               
                 Gen 6 
                 1500 
                 1850 
                 2.78 
                 26 
               
               
                 Gen 7.5 
                 1950 
                 2250 
                 4.39 
                 23 
               
               
                 Gen 8 
                 2160 
                 2400 
                 5.18 
                 21 
               
               
                 Gen 8 
                 2160 
                 2460 
                 5.31 
                 21 
               
               
                 Gen 8.5 
                 2200 
                 2500 
                 5.5 
                 21 
               
               
                 Gen 9 
                 2400 
                 2800 
                 6.72 
                 20 
               
               
                 Gen 10 
                 2850 
                 3050 
                 8.69 
                 19 
               
               
                   
               
            
           
         
       
     
     Accordingly, the design of various embodiments of first tunnel circulation and filtration system  1500 , in conjunction with other low-particle systems and methods of the present teachings, can provide a substantially low particle environment proximal a substrate for various embodiments of a gas enclosure system. As previously discussed herein, such a substantially low particle environment can have a specification for airborne particulate matter, as well as for on-substrate particulate matter. various embodiments of a multi-zone gas circulation and filtration system of the present teachings can effectively remove both airborne particulate matter in various sections of a gas enclosure, as well as particulate matter generated proximal to a substrate, for example, during a printing process. 
       FIG. 5A  is a schematic top section view of gas enclosure system  500 A, depicting various embodiments of a tunnel circulation and filtration zone, as well various embodiments of a bridge circulation and filtration zone. The section is taken through gas enclosure  1002  above opening  1342  of auxiliary enclosure  1330  (see  FIG. 1B ). As previously discussed herein, various embodiments of systems and methods of the present teachings can have a gas enclosure with one auxiliary enclosure. Additionally, for various embodiments of systems and methods of the present teachings, a gas enclosure can have two auxiliary enclosures. In the schematic rending of  FIG. 5A , tunnel cross flow circulation path  20  is depicted for first tunnel enclosure section  1200  and second tunnel enclosure section  1400  of gas enclosure system  500 A. Tunnel cross flow circulation path  20  of  FIG. 5A  is depicted as a flow path circulating gas around a printing system, which can include floatation table  2200  (see  FIG. 1B ). According to various embodiments of a multi-zone circulation and filtration system of the present teachings, first tunnel circulation and filtration system  1500 A can be positioned approximately mid-way in first tunnel enclosure section  1200 . For various embodiments of systems and methods of the present teachings, gas enclosure system  500 A may utilize a single tunnel circulation and filtration system. As depicted in  FIG. 5A , various systems and methods of the present teachings can utilize two tunnel circulation and filtration systems, and can include second tunnel circulation and filtration system  1500 B, which can be positioned approximately mid-way in second tunnel enclosure section  1400 . 
     For gas enclosure system  500 A of  FIG. 5A , tunnel baffle plate  2150 , mounted in bridge enclosure section  1300 , can have first riser opening  2152 , which accommodates first riser  2120 , as well as having second riser opening  2154  for accommodating second riser  2122 . Additionally, tunnel baffle plate  2150  can have carriage assembly opening  2156 , which can allow for the movement of various carriage assemblies that can be mounted on a printing system bridge, such as X-axis carriage assembly  2301  depicted in  FIG. 5A . Tunnel baffle plate carriage assembly opening  2156  can be in flow communication with various embodiments of a bridge circulation and filtration zone. Tunnel baffle plate carriage assembly opening  2156  can allow for transition zone flow path  30 , as indicated by the direction of flow indicators in transition zone flow path  30 . As such, tunnel baffle plate  2150  provides for flow communication from a tunnel circulation and filtration zone to a bridge circulation and filtration zone. 
       FIG. 5B  is a schematic long section view through gas enclosure system  500 A. Gas enclosure system  500 A can have a printing system that can include floatation table  2200  that is supported by a first set of isolators  2110  and a second set of isolators  2112 , as well as mounted on printing system base  2100 . In  FIG. 5B , tunnel cross flow circulation path  20  is depicted in long section view of gas enclosure  1002 , with flow direction indicators showing the cross circulation path of filtered gas in the tunnel circulation and filtration zone of gas enclosure system  500 A. Gas enclosure  1002  can have inlet opening or inlet gate  1242  for receiving a substrate, as well as outlet opening or outlet gate  1442  for transitioning a substrate from gas enclosure assembly  500 A. In various embodiments of gas enclosure system  500 A, there may be only a single gate  1242 , which can be both an inlet and outlet gate. Various embodiments of a Y-axis motion system can move a substrate in the Y-axis direction relative to X-axis carriage assembly  2301  mounted on bridge  2130 , which can have at least one printhead assembly mounted thereupon, such as printhead assembly  2500  depicted in  FIG. 5B . 
     As depicted in  FIG. 5B  for gas enclosure system  500 A, tunnel baffle plate carriage assembly opening  2156  can allow for transition zone flow path  30 . In that regard, tunnel baffle plate  2150  can provide flow communication between a tunnel circulation and filtration zone and a bridge circulation and filtration zone. Bridge circulation and filtration system  1550 A can have bridge circulation flow path  40 , which can draw filtered gas in an upward direction around, for example, X-axis carriage assembly  2301 . Bridge circulation and filtration system  1550 A can include service bundle housing exhaust system  2400 , which can include service bundle housing  2410 , as well as bridge enclosure section exhaust duct  2450 , which can exhaust service bundle housing  2410 , and generally the bridge enclosure section, as indicated by flow path  40 . Bridge enclosure section exhaust duct  2450  can have bridge enclosure section exhaust duct diffuser  2455 , which can provide for a desired controlled pressure drop that can result in a controlled flow into bridge enclosure section exhaust duct  2450 . In various embodiments, bridge enclosure section exhaust duct diffuser  2455  can be a perforated metallic plate for creating a controlled distribution of flow. Various embodiments of bridge enclosure section exhaust duct diffuser  2455  can be a filtration material having, for example, but not limited by, a porous structure for creating a controlled distribution of flow. For various embodiments of bridge enclosure section exhaust duct diffuser  2455 , gas flowing through the diffuser can provide for a desired controlled pressure drop, which can result in a controlled flow on an exit side of a diffuser. For example, a diffuser can be designed to offset an uneven flow profile entering a flow-directing structure, such as a duct, a baffle or a plenum, leading to uniform flow on an exit side of a diffuser. Additionally, various embodiments of a diffuser according to the present teachings can be designed for a specifically controlled non-uniform flow profile on an exit side of a diffuser. 
     Bridge circulation and filtration system  1550 A can include bridge circulation and filtration system intake duct  1560 , which can be in flow communication with bridge enclosure section exhaust duct  2450 . Bridge circulation and filtration system  1550 A can include fan  1570 , heat exchanger  1580 , and filter  1590 , which can be mounted within bridge circulation and filtration system intake duct  1560 . For various embodiments of bridge circulation and filtration system  1550 A, fan  1570  and filter unit  1590  can be combined into a fan filter unit. Bridge circulation and filtration system intake duct  1560  can be in flow communication with bridge circulation and filtration system return duct  1565 . Bridge circulation and filtration system return duct  1565  can be in flow communication with a tunnel enclosure section, as indicated in  FIG. 5B . Gas enclosure system  500 A of  FIG. 5B  can have more than one bridge circulation and filtration return duct. For various embodiments of a multi-zone circulation and filtration system, a bridge circulation and filtration system return duct can complete the flow communication between a tunnel circulation and filtration zone and a bridge circulation and filtration zone. 
     Various embodiments of a cross flow design for systems and methods of the present teachings may utilize a combination of flow-directing structures, such as baffle plates, ducts and plenums to provide for a tunnel circulation and filtration zone and a bridge circulation and filtration zone that are not in active flow communication via a flow-directing structure. For example,  FIG. 6  illustrates generally a cross section view of an embodiments of the present teachings in which a tunnel circulation and filtration zone and a bridge circulation and filtration zone that are substantially independent zones not in directed flow communication via a flow-directing structure. 
     Similarly to gas enclosure system  500 A of  FIG. 3A  and  FIG. 3B ,  FIG. 6  illustrates generally tunnel circulation and filtration system  1500 B of gas enclosure system  500 B. Additionally, for perspective and context, features as described for various embodiments of gas enclosure  1000  of  FIG. 1A , as well as printing system  2000  of  FIG. 1B  and  FIG. 1C  are depicted in phantom view through a section of bridge enclosure section  1300 . Gas enclosure system  500 B can have printing system  2002 , which can be housed in gas enclosure  1002 . Printing system  2002  can have printing system base  2100 , which can be supported by at least two sets of isolators such as isolator set  2110  that includes isolators  2110 A and  2110 B of  FIG. 3A  and  FIG. 3B . A Y-axis motion system can be mounted on printing system base  2100  and can include Y-axis track  2350 , supported by Y-axis track support  2355 . Substrate  2050  can be floatingly supported by substrate floatation table  2200 . Printing system base  2100  can support first riser  2120  and second riser  2122 , upon which bridge  2130  can be mounted. Printing system bridge  2130  can support first X-axis carriage assembly  2301 , upon which printhead assembly  2500  can be mounted, and second X-axis carriage assembly  2302 , upon which camera assembly  2550  can be mounted. 
     Additionally, gas enclosure system  500 B of  FIG. 6  can have auxiliary enclosure  1330 , depicted in phantom view, which can enclose printhead management system  2701 . Printing system  2000  of  FIG. 1B  depicts a gas enclosure having first auxiliary enclosure  1330  and second auxiliary enclosure  1370 , while in  FIG. 6 , auxiliary enclosure  1330  is indicated. As such, various embodiments of systems and methods of the present teachings can have a gas enclosure with one auxiliary enclosure. In various embodiments of systems and methods of the present teachings, a gas enclosure can have two auxiliary enclosures. Auxiliary enclosure  1330  can be in flow communication with the printing system enclosure of gas enclosure system  500 B through printhead assembly opening  1342 , and can be sealably isolated from the remaining volume of gas enclosure  1002 , by way of non-limiting example, by docking first printhead assembly  2500  onto first printhead assembly docking gasket  1345 . As will be discussed in more detail subsequently herein, for various embodiments of a multi-zone gas circulation and filtration system of the present teachings, floor panel assembly  1341  (see also  FIG. 1B ) shown in phantom view in  FIG. 6  can be configured as an auxiliary enclosure baffle structure for directing the flow of air into auxiliary enclosure  1330 . 
     Similarly to what has been described for  FIG. 3A , various embodiments of systems and methods illustrated generally by  FIG. 6  can have a first tunnel enclosure section, and a second tunnel enclosure section, for example, as first tunnel enclosure section  1200  and second tunnel enclosure section  1400  of  FIG. 1A . In various embodiments, each tunnel enclosure section can have a tunnel circulation and filtration system providing cross-flow about the tunnel enclosure section. Various embodiments of a tunnel circulation and filtration system of  FIG. 6  can have a tunnel circulation and filtration system providing cross-flow for both the first tunnel enclosure section, as well as the second tunnel enclosure section. As illustrated generally in the schematic front cross-section view of  FIG. 6 , various embodiments of tunnel circulation and filtration system  1500  can include inlet baffle  2140 , which can include inlet baffle support  2142 . Inlet baffle  2140 , in conjunction with tunnel enclosure  1200 , can direct the flow of gas across floatation table  2200 . Tunnel circulation and filtration system  1500  can include gas intake housing  1510 , in which fan  1520 , heat exchanger  1530 , and filter unit  1540  can be mounted in series. Filter unit  1540  can have tunnel circulation and filtration diffuser  1545  in series with filter unit  1540 , as depicted in  FIG. 6 . In various embodiments, tunnel circulation and filtration diffuser  1545  can be a perforated metallic plate for creating a controlled distribution of flow. Various embodiments of tunnel circulation and filtration diffuser  1545  can be a filtration material having, for example, but not limited by, a porous structure for creating a controlled distribution of flow. For various embodiments of tunnel circulation and filtration diffuser  1545 , gas flowing through the diffuser can provide for a desired controlled pressure drop, which can result in a controlled flow on an exit side of a diffuser. For example, a diffuser can be designed to offset an uneven flow profile entering a flow-directing structure, such as a duct, a baffle or a plenum, leading to uniform flow on an exit side of a diffuser. Additionally, various embodiments of a diffuser according to the present teachings can be designed for a specifically controlled non-uniform flow profile on an exit side of a diffuser. 
     For various embodiments of tunnel circulation and filtration system  1500 , fan  1520  and filter unit  1540  can be combined into a fan filter unit. Various embodiments of a tunnel circulation and filtration zone can include outlet baffle  2141 , which can include outlet baffle support  2143 . Outlet baffle  2141 , in conjunction with tunnel enclosure  1200 , can direct the flow of gas in a downward direction to be circulated across floatation table  2200  and around a portion of a printing system housed in a first tunnel enclosure and second tunnel enclosure section (see also  FIG. 1B ), thereby providing a cross-flow path in a first tunnel enclosure and second tunnel enclosure section. In that regard, various embodiments of systems and methods of the present teachings can have a first tunnel circulation and filtration zone, as well as a second tunnel circulation and filtration zone. Various embodiments of tunnel circulation and filtration system  1500  can provide filtered gas that circulates across the tunnel zone of a gas enclosure system. 
     For various systems and methods illustrated generally by  FIG. 6 , as previously discussed herein for  FIG. 3A ,  FIG. 3B , as well as  FIG. 4 , a tunnel circulation and filtration system, such as tunnel circulation and filtration system  1500 A can direct inert gas across substrate  2050 . For gas enclosure system  500 A, inlet baffle  2140  and outlet baffle  2141 , in conjunction with first tunnel enclosure section  1200  can be used to direct the flow of filtered gas laterally, so that gas is circulated in a cross-flow path through gas enclosure system  500 A. Additionally, for various systems and methods illustrated generally by  FIG. 6 , as previously discussed herein for  FIG. 4  and Table 3, the cross flow of gas in a printing region proximal to a substrate can remove particles that may be generated by various printing system devices and apparatuses. As such, in addition to providing a low-particle environment throughout a tunnel enclosure section, the cross flow of gas in a printing region proximal to a substrate provides for a low-particle environment in a printing area proximal to a substrate. 
       FIG. 7A  is a schematic top section view of gas enclosure system  500 B, depicting various embodiments of a tunnel circulation and filtration zone, as well various embodiments of a bridge circulation and filtration zone. The section is taken through gas enclosure  1002 , at about the level of floor panel assembly  1341  (see also  FIG. 1B ), which can be configured as an auxiliary enclosure baffle structure for directing the flow of air into auxiliary enclosure  1330 , as indicated in  FIG. 7A . Auxiliary enclosure baffle structure  1341  can have opening  1342  of auxiliary enclosure  1330  (see  FIG. 1B ), around which gasket  1345  can be mounted. As previously discussed herein, various embodiments of systems and methods of the present teachings can have a gas enclosure with one auxiliary enclosure. Additionally, for various embodiments of systems and methods of the present teachings, a gas enclosure can have two auxiliary enclosures. In the schematic rending of  FIG. 7A , tunnel cross flow circulation path  20  is depicted for first tunnel enclosure section  1200  and second tunnel enclosure section  1400  of gas enclosure system  500 B. Cross flow circulation path  20  of  FIG. 7A  is depicted as a flow path circulating gas around a printing system, which can include floatation table  2200  (see  FIG. 1B ). According to various embodiments of a multi-zone circulation and filtration system of the present teachings, first tunnel circulation and filtration system  1500 A can be positioned approximately mid-way in first tunnel enclosure section  1200 . For various embodiments of systems and methods of the present teachings, gas enclosure system  500 B may utilize a single tunnel circulation and filtration system. As depicted in  FIG. 6 , various systems and methods of the present teachings can utilize two tunnel circulation and filtration systems, and can include second tunnel circulation and filtration system  1500 B, which can be positioned approximately mid-way in second tunnel enclosure section  1400 . 
     Gas enclosure system  500 B of  FIG. 7A  can have first riser  2120  and second riser  2122  for supporting bridge  2130  (see  FIG. 6 ), upon which carriage assembly  2301  can be mounted. Bridge circulation and filtration system  1550 B of gas enclosure system  500 B of  FIG. 7A  can have bridge enclosure section first return duct  1566  and bridge enclosure section second return duct  1568 , which can direct gas circulating into a bridge enclosure section output plenum  1568 . Bridge enclosure section output plenum  1568  can have bridge circulation and filtration diffuser  1569 . In various embodiments, bridge circulation and filtration diffuser  1569  can be a perforated metallic plate for creating a controlled distribution of flow. Various embodiments of bridge circulation and filtration diffuser  1569  can be a filtration material having, for example, but not limited by, a porous structure for creating a controlled distribution of flow. For various embodiments of bridge circulation and filtration diffuser  1569 , gas flowing through the diffuser can provide for a desired controlled pressure drop, which can result in a controlled flow on an exit side of a diffuser. For example, a diffuser can be designed to offset an uneven flow profile entering a flow-directing structure, such as a duct, a baffle or a plenum, leading to uniform flow on an exit side of a diffuser. Additionally, various embodiments of a diffuser according to the present teachings can be designed for a specifically controlled non-uniform flow profile on an exit side of a diffuser. On the wall of the bridge enclosure section  1300  opposing the wall on which bridge circulation and filtration diffuser  1569  is located, a bridge enclosure section baffle can be mounted (not shown), which in conjunction with the bridge enclosure wall, can direct gas up around a printing system bridge and related apparatuses and devices. In that regard, various embodiments of a bridge circulation and filtration system of  FIG. 7A  can have flow directing structures such as a first and second return duct in flow communication with an output plenum with a flow diffuser, which can direct a flow of gas towards a baffle that can direct the gas up and around a printing system bridge and related apparatuses and devices and away from a substrate in a printing region. 
     As depicted in  FIG. 7B  for gas enclosure system  500 B, bridge enclosure section baffle  2157  can direct gas up and around printhead assembly  2500 . Bridge circulation and filtration system  1550 B can have bridge circulation flow path  40 , which can draw filtered gas in an upward direction around, for example, X-axis carriage assembly  2301 . Bridge circulation and filtration system  1550 B can include service bundle housing exhaust system  2400 , which can include service bundle housing  2410 , as well as bridge enclosure section exhaust duct  2450 , which can exhaust service bundle housing  2410 , and generally the bridge enclosure section, as indicated by flow path  40 . Bridge enclosure section exhaust duct  2450  can have bridge enclosure section exhaust duct diffuser  2455 , which can provide for a desired controlled pressure drop that can result in a controlled flow into bridge enclosure section exhaust duct  2450 . In various embodiments, bridge enclosure section exhaust duct diffuser  2455  can be a perforated metallic plate for creating a controlled distribution of flow. Various embodiments of bridge enclosure section exhaust duct diffuser  2455  can be a filtration material having, for example, but not limited by, a porous structure for creating a controlled distribution of flow. For various embodiments of bridge enclosure section exhaust duct diffuser  2455 , gas flowing through the diffuser can provide for a desired controlled pressure drop, which can result in a controlled flow on an exit side of a diffuser. For example, a diffuser can be designed to offset an uneven flow profile entering a flow-directing structure, such as a duct, a baffle or a plenum, leading to uniform flow on an exit side of a diffuser. Additionally, various embodiments of a diffuser according to the present teachings can be designed for a specifically controlled non-uniform flow profile on an exit side of a diffuser. 
     Bridge circulation and filtration system  1550 B can include bridge circulation and filtration system intake duct  1560 , which can be in flow communication with bridge enclosure section exhaust duct  2450 . Bridge circulation and filtration system  1550 A can include fan  1570 , heat exchanger  1580 , and filter  1590 , which can be mounted within bridge circulation and filtration system intake duct  1560 . For various embodiments of bridge circulation and filtration system  1550 A, fan  1570  and filter unit  1590  can be combined into a fan filter unit. Bridge circulation and filtration system intake duct  1560  can be in flow communication with bridge circulation and filtration system return first duct  1564  and bridge circulation and filtration system return second duct  1566 . Bridge circulation and filtration system return first duct  1564  and bridge circulation and filtration system return second duct  1566  can be in flow communication with bridge enclosure section output plenum  1568  as indicated in  FIG. 7B . Circulating gas can then flow through bridge circulation and filtration diffuser  1569 , and can then be directed towards bridge enclosure section baffle  2157 , completing bridge circulation flow path  40  thereby. 
     According to the present teachings, as depicted and illustrated generally for  FIGS. 3A-7B , various embodiments of a multi-zone gas circulation and filtration system can effectively remove airborne particulate matter in various sections of a gas enclosure, such as a tunnel enclosure section and a bridge enclosure section. Additionally, various embodiments of a multi-zone gas circulation and filtration system of the present teachings can remove particulate matter generated proximal to a substrate during, for example, a printing process by utilizing various embodiments of a tunnel circulation and filtration system together with a bridge circulation and filtration system. 
       FIG. 8  is a schematic diagram showing a gas enclosure system  501 . Various embodiments of a gas enclosure system  501  according to the present teachings can comprise gas enclosure assembly  1003  for housing a printing system, gas purification loop  3130  in fluid communication gas enclosure assembly  1003 , and at least one thermal regulation system  3140 . Additionally, various embodiments of gas enclosure system  501  can have pressurized inert gas recirculation system  3000 , which can supply inert gas for operating various devices, such as a substrate floatation table for an OLED printing system. Various embodiments of a pressurized inert gas recirculation system  3000  can utilize a compressor, a blower and combinations of the two as sources for various embodiments of pressurized inert gas recirculation system  3000 , as will be discussed in more detail subsequently herein. Additionally, gas enclosure system  501  can have a circulation and filtration system internal to gas enclosure system  501  (not shown). 
     As depicted in, for example,  FIG. 3A ,  FIG. 3B ,  FIG. 5A ,  FIG. 5B ,  FIG. 6 ,  FIG. 7A  and  FIG. 7B , for various embodiments of a gas enclosure assembly according to the present teachings, the design of a two zone tunnel circulation and filtration system, and a bridge circulation and filtration system can separate the inert gas circulated through gas purification loop  3130  from the inert gas that is continuously filtered and circulated internally for various embodiments of a gas enclosure assembly. Gas purification loop  3130  includes gas purification outlet line  3131  from gas enclosure assembly  1003 , to a solvent removal component  3132  and then to gas purification system  3134 . Inert gas purified of solvent and other reactive gas species, such as oxygen, ozone, and water vapor, are then returned to gas enclosure assembly  1003  through gas enclosure gas purification inlet line  3133 , which receives purified gas from a gas purification outlet line. Gas purification loop  3130  may also include appropriate conduits and connections, and sensors, for example, oxygen, ozone, water vapor and solvent vapor sensors. A gas circulating unit, such as a fan, blower or motor and the like, can be separately provided or integrated, for example, in gas purification system  3134 , to circulate gas through gas purification loop  3130 . According to various embodiments of a gas enclosure assembly, though solvent removal system  3132  and gas purification system  3134  are shown as separate units in the schematic shown in  FIG. 8 , solvent removal system  3132  and gas purification system  3134  can be housed together as a single purification unit. 
     Gas purification loop  3130  of  FIG. 8  can have solvent removal system  3132  placed upstream of gas purification system  3134 , so that inert gas circulated from gas enclosure assembly  1003  passes through solvent removal system  3132  via gas purification outlet line  3131 . According to various embodiments, solvent removal system  3132  may be a solvent trapping system based on adsorbing solvent vapor from an inert gas passing through solvent removal system  3132  of  FIG. 8 . A bed or beds of a sorbent, for example, but not limited by, such as activated charcoal, molecular sieves, and the like, may effectively remove a wide variety of organic solvent vapors. For various embodiments of a gas enclosure system cold trap technology may be employed to remove solvent vapors in solvent removal system  3132 . As previously discussed herein, for various embodiments of a gas enclosure system according to the present teachings, sensors, such as oxygen, ozone, water vapor and solvent vapor sensors, may be used to monitor the effective removal of such species from inert gas continuously circulating through a gas enclosure system, such as gas enclosure system  501  of  FIG. 8 . Various embodiments of a solvent removal system can indicate when sorbent, such as activated carbon, molecular sieves, and the like, has reached capacity, so that the bed or beds of sorbent can be regenerated or replaced. Regeneration of a molecular sieve can involve heating the molecular sieve, contacting the molecular sieve with a forming gas, a combination thereof, and the like. Molecular sieves configured to trap various species, including oxygen, ozone, water vapor, and solvents, can be regenerated by heating and exposure to a forming gas that comprises hydrogen, for example, a forming gas comprising about 96% nitrogen and 4% hydrogen, with said percentages being by volume or by weight. Physical regeneration of activated charcoal can be done using a similar procedure of heating under an inert environment. 
     Any suitable gas purification system can be used for gas purification system  3134  of gas purification loop  3130  of  FIG. 8 . Gas purification systems available, for example, from MBRAUN Inc., of Statham, N.H., or Innovative Technology of Amesbury, Mass., may be useful for integration into various embodiments of a gas enclosure assembly according to the present teachings. Gas purification system  3134  can be used to purify one or more inert gases in gas enclosure system  501 , for example, to purify the entire gas atmosphere within a gas enclosure assembly. As previously discussed herein, in order to circulate gas through gas purification loop  3130 , gas purification system  3134  can have a gas circulating unit, such as a fan, blower or motor, and the like. In that regard, a gas purification system can be selected depending on the volume of the enclosure, which can define a volumetric flow rate for moving an inert gas through a gas purification system. For various embodiments of gas enclosure system having a gas enclosure assembly with a volume of up to about 4 m 3 ; a gas purification system that can move about 84 m 3 /h can be used. For various embodiments of gas enclosure system having a gas enclosure assembly with a volume of up to about 10 m 3 ; a gas purification system that can move about 155 m 3 /h can be used. For various embodiments of a gas enclosure assembly having a volume of between about 52-114 m 3 , more than one gas purification system may be used. 
     Any suitable gas filters or purifying devices can be included in the gas purification system  3134  of the present teachings. In some embodiments, a gas purification system can comprise two parallel purifying devices, such that one of the devices can be taken off line for maintenance and the other device can be used to continue system operation without interruption. In some embodiments, for example, the gas purification system can comprise one or more molecular sieves. In some embodiments, the gas purification system can comprise at least a first molecular sieve, and a second molecular sieve, such that, when one of the molecular sieves becomes saturated with impurities, or otherwise is deemed not to be operating efficiently enough, the system can switch to the other molecular sieve while regenerating the saturated or non-efficient molecular sieve. A control unit can be provided for determining the operational efficiency of each molecular sieve, for switching between operation of different molecular sieves, for regenerating one or more molecular sieves, or for a combination thereof. As previously discussed herein, molecular sieves may be regenerated and reused. 
     Thermal regulation system  3140  of  FIG. 8  can include at least one chiller  3142 , which can have fluid outlet line  3141  for circulating a coolant into a gas enclosure assembly, and fluid inlet line  3143  for returning the coolant to the chiller. An at least one fluid chiller  3142  can be provided for cooling the gas atmosphere within gas enclosure system  501 . For various embodiments of a gas enclosure system of the present teachings, fluid chiller  3142  delivers cooled fluid to heat exchangers within the enclosure, where inert gas is passed over a filtration system internal the enclosure. At least one fluid chiller can also be provided with gas enclosure system  501  to cool heat evolving from an apparatus enclosed within gas enclosure system  501 . For example, but not limited by, at least one fluid chiller can also be provided for gas enclosure system  501  to cool heat evolving from an OLED printing system. Thermal regulation system  3140  can comprise heat-exchange or Peltier devices and can have various cooling capacities. For example, for various embodiments of a gas enclosure system, a chiller can provide a cooling capacity of from between about 2 kW to about 20 kW. Various embodiments of a gas enclosure system can have a plurality of fluid chillers that can chill one or more fluids. In some embodiments, the fluid chillers can utilize a number of fluids as coolant, for example, but not limited by, water, anti-freeze, a refrigerant, and a combination thereof as a heat exchange fluid. Appropriate leak-free, locking connections can be used in connecting the associated conduits and system components. 
     As previously discussed herein, the present teachings disclose various embodiments of a gas enclosure system that can include a printing system enclosure defining a first volume and an auxiliary enclosure defining a second volume. Various embodiments of a gas enclosure system can have an auxiliary enclosure that can be constructed as a sealable section of gas enclosure assembly. According to systems and methods of the present teachings, an auxiliary enclosure can be sealable isolated from a printing system enclosure, and can be opened to an environment external a gas enclosure assembly without exposing a printing system enclosure to the external environment. Such physical isolation of an auxiliary enclosure to perform, for example, but not limited by, various printhead management procedures, can be done to eliminate or minimize the exposure of a printing system enclosure to contamination, such as air and water vapor and various organic vapors, as well as particulate contamination. Various printhead management procedures that can include measurement and maintenance procedures on a printhead assembly can be done with little or no interruption of a printing process, thereby minimizing or eliminating gas enclosure system downtime. 
     For a gas enclosure system having a printing system enclosure defining a first volume and an auxiliary enclosure defining a second volume, both volumes can be readily integrated with gas circulation, filtration and purification components to form a gas enclosure system that can sustain an inert, substantially low-particle environment for processes requiring such an environment with little or no interruption of a printing process. According to various systems and methods of the present teachings, a printing system enclosure may be introduced to a level of contamination that is sufficiently low that a purification system can remove the contamination before it can affect a printing process. Various embodiments of an auxiliary enclosure can be a substantially smaller volume of the total volume of a gas enclosure assembly and can be readily integrated with gas circulation, filtration and purification components to form an auxiliary enclosure system that can rapidly recover an inert, of a low-particle environment after exposure to an external environment, thereby providing little or no interruption of a printing process. 
     According to systems and methods of the present teachings, various embodiments of a printing system enclosure and an auxiliary enclosure constructed as sections of a gas enclosure assembly can be constructed in a fashion to provide for separately-functioning frame member assembly sections. Gas enclosure system  502  of  FIG. 9  can have all elements disclosed, for example, for gas enclosure system  500 A of  FIG. 3A  and  FIG. 3B , and gas enclosure  501  of  FIG. 8 . Additionally, gas enclosure system  502  of  FIG. 9 , can have first gas enclosure assembly section  1004 -S 1  defining a first volume of gas enclosure assembly  1004  and second gas enclosure assembly section  1004 -S 2  defining a second volume of gas enclosure assembly  1004 . If all valves, V 1 , V 2 , V 3  and V 4  are opened, then gas purification loop  3130  operates essentially as previously described for gas enclosure assembly and system  1003  of  FIG. 9 . With closure of V 3  and V 4 , only first gas enclosure assembly section  1004 -S 1  is in fluid communication with gas purification loop  3130 . This valve state may be used, for example, but not limited by, when second gas enclosure assembly section  1004 -S 2  is sealably closed and thereby isolated from first gas enclosure assembly section  1004 -S 1  during various measurement and maintenances procedure requiring that second gas enclosure assembly section  1004 -S 2  be opened to the atmosphere. With closure of V 1  and V 2 , only second gas enclosure assembly section  1004 -S 2  is in fluid communication with gas purification loop  3130 . This valve state may be used, for example, but not limited by, during recovery of second gas enclosure assembly section  1004 -S 2  after the section has been opened to the atmosphere. As previously discussed herein for the present teachings related to  FIG. 9 , the requirements for gas purification loop  3130  are specified with respect to the total volume of gas enclosure assembly  1003 . Therefore, by devoting the resources of a gas purification system to the recovery of a gas enclosure assembly section, such as second gas enclosure assembly section  1004 -S 2 , which is depicted for gas enclosure system  502  of  FIG. 9  to be significantly less in volume than the total volume of gas enclosure  1004 , the recovery time can be substantially reduced. 
     Additionally, various embodiments of an auxiliary enclosure can be readily integrated with a dedicated set of environmental regulation system components, such as lighting, gas circulation and filtration, gas purification, and thermostating components. In that regard, various embodiments of a gas enclosure system that include an auxiliary enclosure that can be sealably isolated as a section of gas enclosure assembly can have a controlled environment that is set to be uniform with a first volume defined by a gas enclosure assembly housing a printing system. Further, various embodiments of a gas enclosure system including an auxiliary enclosure that can be sealably isolated as a section of gas enclosure assembly can have a controlled environment that is set to be different than the controlled environment of a first volume defined by a gas enclosure assembly housing a printing system. 
       FIGS. 10A and 10B  illustrate generally examples of a gas enclosure system for integrating and controlling non-reactive gas and clean dry air (CDA) sources such as can be used to establish the controlled environment referred to in other examples described elsewhere herein, and such as can include a supply of pressurized gas for use with a floatation table.  FIGS. 11A and 11B  illustrate generally examples of a gas enclosure system for integrating and controlling non-reactive gas and clean dry air (CDA) sources such as can be used to establish the controlled environment referred to in other examples described elsewhere herein, and such as can include a blower loop to provide, for example, pressurized gas and at least partial vacuum for use with a floatation table.  FIG. 11C  illustrates generally a further example of a system for integrating and controlling one or more gas or air sources, such as to establish floatation control zones included as a portion of a floatation conveyance system. 
     Recalling, various embodiments of a gas enclosure assembly utilized in embodiments of a gas enclosure system of the present teachings can be constructed in a contoured fashion that minimizes the internal volume of a gas enclosure assembly, and at the same time optimizes the working volume for accommodating various footprints of OLED printing systems designs. For example, various embodiments of a contoured gas enclosure assembly according to the present teachings can have a gas enclosure volume of between about 6 m 3  to about 95 m 3  for various embodiments of a gas enclosure assembly of the present teachings covering, for example, substrate sizes from Gen 3.5 to Gen 10. Various embodiments of a contoured gas enclosure assembly according to the present teachings can have a gas enclosure volume of, for example, but not limited by, of between about 15 m 3  to about 30 m 3 , which might be useful for OLED printing of, for example, Gen 5.5 to Gen 8.5 substrate sizes. Various embodiments of an auxiliary enclosure can be constructed as a section of gas enclosure assembly and readily integrated with gas circulation and filtration, as well as purification components to form a gas enclosure system that can sustain an inert, substantially low-particle environment for processes requiring such an environment. 
     As shown in  FIG. 10A  and  FIG. 11A , various embodiments of a gas enclosure system can include a pressurized inert gas recirculation system  3000 . Various embodiments of a pressurized inert gas recirculation loop can utilize a compressor, a blower and combinations thereof. 
     According to the present teachings, several engineering challenges were addressed in order to provide for various embodiments of a pressurized inert gas recirculation system in a gas enclosure system. First, under typical operation of a gas enclosure system without a pressurized inert gas recirculation system, a gas enclosure system can be maintained at a slightly positive internal pressure relative to an external pressure in order to safeguard against outside gas or air from entering the interior should any leaks develop in a gas enclosure system. For example, under typical operation, for various embodiments of a gas enclosure system of the present teachings, the interior of a gas enclosure system can be maintained at a pressure relative to the surrounding atmosphere external to the enclosure system, for example, of at least 2 mbarg, for example, at a pressure of at least 4 mbarg, at a pressure of at least 6 mbarg, at a pressure of at least 8 mbarg, or at a higher pressure. 
     Maintaining a pressurized inert gas recirculation system within a gas enclosure system can be challenging, as it presents a dynamic and ongoing balancing act regarding maintaining a slight positive internal pressure of a gas enclosure system, while at the same time continuously introducing pressurized gas into a gas enclosure system. Further, variable demand of various devices and apparatuses can create an irregular pressure profile for various gas enclosure assemblies and systems of the present teachings. Maintaining a dynamic pressure balance for a gas enclosure system held at a slight positive pressure relative to the external environment under such conditions can provide for the integrity of an ongoing OLED printing process. For various embodiments of a gas enclosure system, a pressurized inert gas recirculation system according to the present teachings can include various embodiments of a pressurized inert gas loop that can utilize at least one of a compressor, an accumulator, and a blower, and combinations thereof. Various embodiments of a pressurized inert gas recirculation system that include various embodiments of a pressurized inert gas loop can have a specially designed pressure-controlled bypass loop that can provide internal pressure of an inert gas in a gas enclosure system of the present teachings at a stable, defined value. In various embodiments of a gas enclosure system, a pressurized inert gas recirculation system can be configured to recirculate pressurized inert gas via a pressure-controlled bypass loop when a pressure of an inert gas in an accumulator of a pressurized inert gas loop exceeds a pre-set threshold pressure. The threshold pressure can be, for example, within a range from between about 25 psig to about 200 psig, or more specifically within a range of between about 75 psig to about 125 psig, or more specifically within a range from between about 90 psig to about 95 psig. In that regard, a gas enclosure system of the present teachings having a pressurized inert gas recirculation system with various embodiments of a specially designed pressure-controlled bypass loop can maintain a balance of having a pressurized inert gas recirculation system in an hermetically sealed gas enclosure. 
     According to the present teachings, various devices and apparatuses can be disposed in the interior of a gas enclosure system and in fluid communication with various embodiments of a pressurized inert gas recirculation system. For various embodiments of a gas enclosure and system of the present teachings, the use of various pneumatically operated devices and apparatuses can provide low-particle generating performance, as well as being low maintenance. Exemplary devices and apparatuses that can be disposed in the interior of a gas enclosure system and in fluid communication with various pressurized inert gas loops can include, for example, but not limited by, one or more of a pneumatic robot, a substrate floatation table, an air bearing, an air bushing, a compressed gas tool, a pneumatic actuator, and combinations thereof. A substrate floatation table, as well as air bearings can be used for various aspects of operating an OLED printing system in accordance with various embodiments of a gas enclosure system of the present teachings. For example, a substrate floatation table utilizing air-bearing technology can be used to transport a substrate into position in a printhead chamber, as well as to support a substrate during an OLED printing process. 
     For example, as shown in  FIG. 10A  and  FIG. 11A , various embodiments of gas enclosure system  503 A and gas enclosure system  504 A can have external gas loop  3200  for integrating and controlling inert gas source  3201  and clean dry air (CDA) source  3203  for use in various aspects of operation of gas enclosure system  503 A and gas enclosure system  504 A. Gas enclosure system  503 A and gas enclosure system  504 A can also include various embodiments of an internal particle filtration and gas circulation system, as well as various embodiments of an external gas purification system, as previously described. Such embodiments of a gas enclosure system can include a gas purification system for purifying various reactive species from an inert gas. Some commonly used non-limiting examples of an inert gas can include nitrogen, any of the noble gases, and any combination thereof. Various embodiments of a gas purification system according to the present teachings can maintain levels for each species of various reactive species, including various reactive atmospheric gases, such as water vapor, oxygen and ozone, as well as organic solvent vapors at 100 ppm or lower, for example, at 10 ppm or lower, at 1.0 ppm or lower, or at 0.1 ppm or lower. In addition to external loop  3200  for integrating and controlling inert gas source  3201  and CDA source  3203 , gas enclosure system  503 A and gas enclosure system  504 A can have compressor loop  3250 , which can supply inert gas for operating various devices and apparatuses that can be disposed in the interior of gas enclosure system  503 A and gas enclosure system  504 A. 
     Compressor loop  3250  of  FIG. 10A  can include compressor  3262 , first accumulator  3264  and second accumulator  3268 , which are configured to be in fluid communication. Compressor  3262  can be configured to compress inert gas withdrawn from gas enclosure assembly  1005  to a desired pressure. An inlet side of compressor loop  3250  can be in fluid communication with gas enclosure assembly  1005  via gas enclosure assembly outlet  3252  through line  3254 , having valve  3256  and check valve  3258 . Compressor loop  3250  can be in fluid communication with gas enclosure assembly  1005  on an outlet side of compressor loop  3250  via external gas loop  3200 . Accumulator  3264  can be disposed between compressor  3262  and the junction of compressor loop  3250  with external gas loop  3200  and can be configured to generate a pressure of 5 psig or higher. Second accumulator  3268  can be in compressor loop  3250  for providing dampening fluctuations due to compressor piston cycling at about 60 Hz. For various embodiments of compressor loop  3250 , first accumulator  3264  can have a capacity of between about 80 gallons to about 160 gallons, while second accumulator can have a capacity of between about 30 gallons to about 60 gallons. According to various embodiments of gas enclosure system  503 A, compressor  3262  can be a zero ingress compressor. Various types of zero ingress compressors can operate without leaking atmospheric gases into various embodiments of a gas enclosure system of the present teachings. Various embodiments of a zero ingress compressor can be run continuously, for example, during an OLED printing process utilizing the use of various devices and apparatuses requiring compressed inert gas. 
     Accumulator  3264  can be configured to receive and accumulate compressed inert gas from compressor  3262 . Accumulator  3264  can supply the compressed inert gas as needed in gas enclosure assembly  1005 . For example, accumulator  3264  can provide gas to maintain pressure for various components of gas enclosure assembly  1005 , such as, but not limited by, one or more of a pneumatic robot, a substrate floatation table, an air bearing, an air bushing, a compressed gas tool, a pneumatic actuator, and combinations thereof. As shown in  FIG. 10A  for gas enclosure system  503 A, gas enclosure assembly  1005  can have an OLED printing system  2000  enclosed therein. As schematically depicted in  FIG. 10A , inkjet printing system  2000  can be supported by printing system base  2100 , which can be a granite stage. Printing system base  2100  can support a substrate support apparatus, such as a chuck, for example, but not limited by, a vacuum chuck, a substrate floatation chuck having pressure ports, and a substrate floatation chuck having vacuum and pressure ports. In various embodiments of the present teachings, a substrate support apparatus can be a substrate floatation table, such as substrate floatation table  2200  indicated in  FIG. 10A . Substrate floatation table  2200  can be used for the frictionless support of a substrate. In addition to a low-particle generating floatation table, for frictionless Y-axis conveyance of a substrate, printing system  2000  can have a Y-axis motion system utilizing air bushings. 
     Additionally, printing system  2000  can have at least one X,Z-axis carriage assembly with motion control provided by a low-particle generating X-axis air bearing assembly. Various components of a low-particle generating motion system, such as an X-axis air bearing assembly, can be used in place of, for example, various particle-generating linear mechanical bearing systems. For various embodiments of a gas enclosure and system of the present teachings, the use of a variety of pneumatically operated devices and apparatuses can provide low-particle generating performance, as well as being low maintenance. Compressor loop  3250  can be configured to continuously supply pressurized inert gas to various devices and apparatuses of gas enclosure system  503 A. In addition to a supply of pressurized inert gas, substrate floatation table  2200  of inkjet printing system  2000 , which utilizes air bearing technology, also utilizes vacuum system  3270 , which is in communication with gas enclosure assembly  1005  through line  3272  when valve  3274  is in an open position. 
     A pressurized inert gas recirculation system according to the present teachings can have pressure-controlled bypass loop  3260  as shown in  FIG. 10A  for compressor loop  3250 , which acts to compensate for variable demand of pressurized gas during use, thereby providing dynamic balance for various embodiments of a gas enclosure system of the present teachings. For various embodiments of a gas enclosure system according to the present teachings, a bypass loop can maintain a constant pressure in accumulator  3264  without disrupting or changing the pressure in enclosure  1005 . Bypass loop  3260  can have first bypass inlet valve  3261  on an inlet side of bypass loop, which is closed unless bypass loop  3260  is used. Bypass loop  3260  can also have back pressure regulator  3266 , which can be used when second valve  3263  is closed. Bypass loop  3260  can have second accumulator  3268  disposed at an outlet side of bypass loop  3260 . For embodiments of compressor loop  3250  utilizing a zero ingress compressor, bypass loop  3260  can compensate for small excursions of pressure that can occur over time during use of a gas enclosure system. Bypass loop  3260  can be in fluid communication with compressor loop  3250  on an inlet side of bypass loop  3260  when bypass inlet valve  3261  is in an opened position. When bypass inlet valve  3261  is opened, inert gas shunted through bypass loop  3260  can be recirculated to the compressor if inert gas from compressor loop  3250  is not in demand within the interior of gas enclosure assembly  1005 . Compressor loop  3250  is configured to shunt inert gas through bypass loop  3260  when a pressure of the inert gas in accumulator  3264  exceeds a pre-set threshold pressure. A pre-set threshold pressure for accumulator  3264  can be from between about 25 psig to about 200 psig at a flow rate of at least about 1 cubic feet per minute (cfm), or from between about 50 psig to about 150 psig at a flow rate of at least about 1 cubic feet per minute (cfm), or from between about 75 psig to about 125 psig at a flow rate of at least about 1 cubic feet per minute (cfm) or between about 90 psig to about 95 psig at a flow rate of at least about 1 cubic feet per minute (cfm). 
     Various embodiments of compressor loop  3250  can utilize a variety of compressors other than a zero ingress compressor, such as a variable speed compressor or a compressor that can be controlled to be in either an on or off state. As previously discussed herein, a zero ingress compressor ensures that no atmospheric reactive species can be introduced into a gas enclosure system. As such, any compressor configuration preventing atmospheric reactive species from being introduced into a gas enclosure system can be utilized for compressor loop  3250 . According to various embodiments, compressor  3262  of gas enclosure system  503 A can be housed in, for example, but not limited by, an hermetically-sealed housing. The housing interior can be configured in fluid communication with a source of inert gas, for example, the same inert gas that forms the inert gas atmosphere for gas enclosure assembly  1005 . For various embodiments of compressor loop  3250 , compressor  3262  can be controlled at a constant speed to maintain a constant pressure. In other embodiments of compressor loop  3250  not utilizing a zero ingress compressor, compressor  3262  can be turned off when a maximum threshold pressure is reached, and turned on when a minimum threshold pressure is reached. 
     In  FIG. 11A  for gas enclosure system  504 A, blower loop  3280  utilizing vacuum blower  3290  is shown for the operation of substrate floatation table  2200  of inkjet printing system  2000 , which are housed in gas enclosure assembly  1005 . As previously discussed herein for compressor loop  3250 , blower loop  3280  can be configured to continuously supply pressurized inert gas to a substrate floatation table  2200  of printing system  2000 . 
     Various embodiments of a gas enclosure system that can utilize a pressurized inert gas recirculation system can have various loops utilizing a variety of pressurized gas sources, such as at least one of a compressor, a blower, and combinations thereof. In  FIG. 11A  for gas enclosure system  504 A, compressor loop  3250  can be in fluid communication with external gas loop  3200 , which can be used for the supply of inert gas for high consumption manifold  3225 , as well as low consumption manifold  3215 . For various embodiments of a gas enclosure system according to the present teachings as shown in  FIG. 11A  for gas enclosure system  504 A, high consumption manifold  3225  can be used to supply inert gas to various devices and apparatuses, such as, but not limited by, one or more of a substrate floatation table, a pneumatic robot, an air bearing, an air bushing, and a compressed gas tool, and combinations thereof. For various embodiments of a gas enclosure system according to the present teachings, low consumption  3215  can be used to supply inert gas to various apparatuses and devises, such as, but not limited by, one or more of an isolator, and a pneumatic actuator, and combinations thereof. 
     For various embodiments of gas enclosure system  504 A of  FIG. 11A , blower loop  3280  can be utilized to supply pressurized inert gas to various embodiments of substrate floatation table  2200 , while compressor loop  3250 ; in fluid communication with external gas loop  3200 , can be utilized to supply pressurized inert gas to, for example, but not limited by, one or more of a pneumatic robot, an air bearing, an air bushing, and a compressed gas tool, and combinations thereof. In addition to a supply of pressurized inert gas, substrate floatation table  2200  of OLED inkjet printing system  2000 , which utilizes air bearing technology, also utilizes blower vacuum  3290 , which is in communication with gas enclosure assembly  1005  through line  3292  when valve  3294  is in an open position. Housing  3282  of blower loop  3280  can maintain first blower  3284  for supplying a pressurized source of inert gas to substrate floatation table  2200 , and second blower  3290 , acting as a vacuum source for substrate floatation table  2200 , which is housed in an inert gas environment in gas enclosure assembly  1005 . Attributes that can make blowers suitable for use as a source of either pressurized inert gas or vacuum for various embodiments a substrate floatation table include, for example, but not limited by, that they have high reliability; making them low maintenance, have variable speed control, and have a wide range of flow volumes; various embodiments capable of providing a volume flow of between about 100 m 3 /h to about 2,500 m 3 /h. Various embodiments of blower loop  3280  additionally can have first isolation valve  3283  at an inlet end of blower loop  3280 , as well as check valve  3285  and a second isolation valve  3287  at an outlet end of blower loop  3280 . Various embodiments of blower loop  3280  can have adjustable valve  3286 , which can be, for example, but not limited by, a gate, butterfly, needle or ball valve, as well as heat exchanger  3288  for maintaining inert gas from blower loop  3280  to substrate floatation table  2200  at a defined temperature. 
       FIG. 11A  depicts external gas loop  3200 , also shown in  FIG. 10A , for integrating and controlling inert gas source  3201  and clean dry air (CDA) source  3203  for use in various aspects of operation of gas enclosure system  503 A of  FIG. 10A  and gas enclosure system  504 A of  FIG. 11A . External gas loop  3200  of  FIG. 10A  and  FIG. 11A  can include at least four mechanical valves. These valves comprise first mechanical valve  3202 , second mechanical valve  3204 , third mechanical valve  3206 , and fourth mechanical valve  3208 . These various valves are located at positions in various flow lines that allow control of both an inert gas and an air source such as clean dry air (CDA). According to the present teachings, an inert gas may be any gas that does not undergo a chemical reaction under a defined set of conditions. Some commonly used non-limiting examples of an inert gas can include nitrogen, any of the noble gases, and any combination thereof. From a house inert gas source  3201 , a house inert gas line  3210  extends. House inert gas line  3210  continues to extend linearly as low consumption manifold line  3212 , which is in fluid communication with low consumption manifold  3215 . A cross-line first section  3214  extends from a first flow juncture  3216 , which is located at the intersection of house inert gas line  3210 , low consumption manifold line  3212 , and cross-line first section  3214 . Cross-line first section  3214  extends to a second flow juncture  3218 . A compressor inert gas line  3220  extends from accumulator  3264  of compressor loop  3250  and terminates at second flow juncture  3218 . A CDA line  3222  extends from a CDA source  3203  and continues as high consumption manifold line  3224 , which is in fluid communication with high consumption manifold  3225 . A third flow juncture  3226  is positioned at the intersection of a cross-line second section  3228 , clean dry air line  3222 , and high consumption manifold line  3224 . Cross-line second section  3228  extends from second flow juncture  3218  to third flow juncture  3226 . Various components that are high consumption can be supplied CDA during maintenance, by means high consumption manifold  3225 . Isolating the compressor using valves  3204 ,  3208 , and  3230  can prevent reactive species, such as oxygen, ozone and water vapor from contaminating an inert gas within the compressor and accumulator. 
     By contrast with  FIGS. 10A and 11A ,  FIGS. 10B and 11B  illustrate generally a configuration wherein a pressure of gas inside the gas enclosure assembly  1005  can be maintained within a desired or specified range, such as using a valve coupled to a pressure monitor, P, where the valve allows gas to be exhausted to another enclosure, system, or a region surrounding the gas enclosure assembly  1005  using information obtained from the pressure monitor. Such gas can be recovered and re-processed as in other examples described herein. As mentioned above, such regulation can assist in maintaining a slight positive internal pressure of a gas enclosure system, because pressurized gas is also contemporaneously introduced into the gas enclosure system. Variable demand of various devices and apparatuses can create an irregular pressure profile for various gas enclosure assemblies and systems of the present teachings. Accordingly, the approach shown in  FIGS. 10B and 11B  for gas enclosure systems  503 B and  504 B, respectively, can be used in addition or instead of other approaches described herein such as to assist in maintaining a dynamic pressure balance for a gas enclosure system held at a slight positive pressure relative to the environment surrounding the enclosure. 
       FIG. 11C  illustrates generally a further example of printing system  504 C for integrating and controlling one or more gas or air sources, such as to establish floatation control zones included as a portion of a floatation conveyance system. Similar to the examples of  FIG. 1C , as well as  FIG. 10A  through  FIG. 11B ,  FIG. 11C  illustrates generally floatation table  2200 . Additionally shown in the illustrative example of  FIG. 11C  are first region  2201 , printing region  2202 , and second region  2203 . According to various embodiments of printing system  504 C of  FIG. 11C , first region  2201  can be an input region, and second region  2203  can be an output region. For various embodiments of printing system  504 C of  FIG. 11C , first region  2201  can be both an input and an output region. Function referred to in association with regions  2201 ,  2202 , and  2203 , such as input, printing, and output for illustration only. Such regions can be used for other processing steps, such as conveyance of a substrate, or support of a substrate such as during one or more of holding, drying, or thermal treatment of the substrate in one or more other modules. In the illustration of  FIG. 11C , a first blower  3284 A is configured to provide pressurized gas in one or more of the input or output regions  2201  or  2203  of a floatation table apparatus. Such pressurized gas can be temperature controlled such as using a first chiller  142 A coupled to a first heat exchanger  1502 A. Such pressurized gas can be filtered using a first filter  1503 A. A temperature monitor  8701 A can be coupled to the first chiller  142  (or other temperature controller). 
     Similarly, as depicted in  FIG. 11C , a second blower  3284 B can be coupled to the printing region  2202  of the floatation table. A separate chiller  142 B can be coupled to a loop including a second heat exchanger  1502 B and a second filter  1503 B. A second temperature monitor  8701 B can be used to provide independent regulation of the temperature of pressurized gas provided by the second blower  3284 B. In this illustrative example, as previously described herein for  FIG. 1C , first and second regions  2201  and  2203  can be supplied with positive pressure, while printing region  2202  can include use of a combination of positive pressure and vacuum control to provide precise control over the substrate position. For example, using such a combination of positive pressure and vacuum control, the substrate can be exclusively controlled using the floating gas cushion provided by gas enclosure system  504 C in the zone defined by the printing region  2202 . The vacuum can be established by a third blower  3290 , such as also provided at least a portion of the make-up gas for the first and second blowers  3284 A or  3284 B within the blower housing  3282 . 
       FIG. 12  depicts a perspective view of OLED printing tool  4000  according to various embodiments of the present teachings, which can include first module  4400 , printing module  4500 , and second module  4600 . Various modules, such as first module  4400  can have first transfer chamber  4410 , which can have a gate, such as gate  4412 , for each side of first transfer chamber  4410  to accommodate various chambers having a specified function. As depicted in  FIG. 12  first transfer chamber  4410  can have a load lock gate (not shown) for integration of first load lock chamber  4450  with first transfer chamber  4410 , as well as a buffer gate (not shown) for integration of first buffer chamber  4460  with first transfer chamber  4410 . Gate  4412  of first transfer chamber  4410  can be used for a chamber or unit that can be movable, such as, but not limited by, a load lock chamber. Observation windows, such as observation windows  4402  and  4404  of first transfer chamber  4410 , as well as observation window  4406  of first buffer chamber  4460 , can be provided for an end user to, for example, monitor a process. Printing module  4500  can include gas enclosure assembly  4510 , which can have first panel assembly  4520 , printing system enclosure assembly  4540 , and second panel assembly  4560 . Similar to gas enclosure assembly  1000  of  FIG. 1B , gas enclosure assembly  4510  can house various embodiments of a printing system. Second module  4600  can include second transfer chamber  4610 , which can have a gate, such as gate  4612 , for each side of second transfer chamber  4610  to accommodate various chambers having a specified function. As depicted in  FIG. 12  second transfer chamber  4610  can have a load lock gate (not shown) for integration of second load lock chamber  4650  with second transfer chamber  4610 , as well as a buffer gate (not shown) for integration of second buffer chamber  4660  with second transfer chamber  4610 . Gate  4612  of second transfer chamber  4610  can be used for a chamber or unit that can be movable, such as, but not limited by, a load lock chamber. Observation windows, such as observation windows  4602  and  4604  of second transfer chamber  4610 , can be provided for an end user to, for example, monitor a process. 
     First load lock chamber  4450  and second load lock chamber  4650  can be affixably associated with first transfer chamber  4410  and second transfer chamber  4610 , respectively or can be movable, such as on wheels or on a track assembly, so that they can be readily positioned for use proximal a chamber. A load lock chamber can be mounted to a support structure and can have at least two gates. For example first load lock chamber  4450  can be supported by first support structure  4454  and can have first gate  4452 , as well as a second gate (not shown) that can allow fluid communication with first transfer module  4410 . Similarly, second load lock chamber  4650  can be supported by second support structure  4654  and can have second gate  4652 , as well as a first gate (not shown) that can allow fluid communication with second transfer module  4610 . 
     As previously discussed herein, various embodiments of a gas enclosure system can have an auxiliary enclosure that can be constructed as a sealable section of gas enclosure assembly. According to systems and methods of the present teachings, an auxiliary enclosure can be sealable isolated from a printing system enclosure, and can be opened to an environment external a gas enclosure assembly without exposing a printing system enclosure to the external environment. Such physical isolation of an auxiliary enclosure to perform, for example, but not limited by, various printhead management procedures, can be done to eliminate or minimize the exposure of a printing system enclosure to contamination, such as air and water vapor and various organic vapors, as well as particulate contamination. Various printhead management procedures that can include measurement and maintenance procedures on a printhead assembly can be done with little or no interruption of a printing process, thereby minimizing or eliminating gas enclosure system downtime. 
     For example, as depicted in  FIG. 13A  through  FIG. 13D , gas enclosure system  505  can have first tunnel enclosure section  1200 , which can have inlet gate  1242  for receiving a substrate, and bridge enclosure section  1300 , as well as auxiliary enclosure  1330 , which can be sealably isolated from the remaining volume of gas enclosure system  505 . As previously discussed herein for  FIG. 3A  and  FIG. 3B , purified inert gas from a purification system, such as purification system  3130  of  FIG. 8  and  FIG. 9 , can circulate into gas enclosure system  505 , for example, into bridge enclosure section  1300 , from a gas purification inlet line, such as gas purification inlet line  3133  of  FIG. 3A ,  FIG. 3B ,  FIG. 6 ,  FIG. 8  and  FIG. 9 . As depicted In  FIG. 13A , during, for example, a printing procedure, inert gas can be circulated to a gas purification system, such as purification system  3130  of  FIG. 8  and  FIG. 9 , from a gas purification outlet line, such as gas purification outlet line  3131 A of  FIG. 3A . As depicted in  FIG. 13B , during, for example, a maintenance procedure, auxiliary enclosure  1330  can be opened to the external environment for access after being sealably isolated from the remaining volume of gas enclosure system  505 . During such a procedure, inert gas can be circulated to a gas purification system, such as purification system  3130  of  FIG. 8  and  FIG. 9 , from a gas purification outlet line, such as gas purification outlet line  3131 B of  FIG. 3B . Purified inert gas can be returned to gas enclosure system  505  from a gas purification system, such as purification system  3130  of  FIG. 8  and  FIG. 9 , from a gas purification inlet line, such as gas purification inlet line  3133  of  FIG. 3A ,  FIG. 3B ,  FIG. 6 ,  FIG. 8  and  FIG. 9 . 
     As depicted in  FIG. 13C , after a procedure, such as a maintenance procedure, has been completed, auxiliary enclosure  1330  can be isolated from the external environment. During, for example, a recovery procedure for auxiliary enclosure  1330  after it has been opened to the external environment for access, an inert purge gas from an inert gas source, such as inert gas source  3201  of  FIG. 10A  and  FIG. 11A , can be circulated through auxiliary enclosure  1330  while it is still sealably isolated from the remaining volume of gas enclosure system  505 . During such a procedure, inert gas can be circulated to a gas purification system, such as purification system  3130  of  FIG. 8  and  FIG. 9 , from a gas purification outlet line, such as gas purification outlet line  3131 B of  FIG. 3B . Purified inert gas can be returned to gas enclosure system  505  from a gas purification system, such as purification system  3130  of  FIG. 8  and  FIG. 9 , from a gas purification inlet line, such as gas purification inlet line  3133  of  FIG. 3A ,  FIG. 3B ,  FIG. 8  and  FIG. 9 . Finally, as depicted in  FIG. 13D , once auxiliary enclosure  1330  has been fully recovered, as depicted in gas enclosure system  505  can be returned to the same flow communication path as described for  FIG. 13A . 
     It should be understood that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure. For example, while vastly different arts such as chemistry, biotechnology, high technology and pharmaceutical arts may benefit from the present teachings. OLED printing is used to exemplify the utility of various embodiments of a gas enclosure system according to the present teachings. Various embodiments of a gas enclosure system that may house an OLED printing system can provide features such as, but not limited by, a controlled, low-particle environment in a contoured enclosure volume, and ready access from the exterior to the interior during processing, as well as during maintenance. Such features of various embodiments of a gas enclosure system may have an impact on functionality, such as, but not limited by, structural integrity providing ease of maintaining low levels of reactive species during processing, as well as rapid enclosure-volume turnover minimizing downtime during maintenance cycles. As such, various features and specifications providing utility for OLED panel printing may also provide benefit to a variety of technology areas. 
     While embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. It is intended that the following claims define the scope of the disclosure and that methods and structures within the scope of these claims and their equivalents be covered thereby.