Active cooling heat sink for ovjp print head

Abstract

Embodiments of the present application relate to an actively cooled heat sink for an OVJP print head. An OVJP apparatus comprising an organic vapor jet printing OVJP print head having a nozzle configured to jet an organic material entrained in a carrier gas, one or more heaters to heat the nozzle, and one or more heat sinks to remove heat from the nozzle area is provided. OVJP deposition apparatus and techniques are also provided in which a heat sink is disposed in the area of one or more OVJP nozzles that maintains an ambient temperature of no more than 40°C when the print head is operated at an operating temperature of 450°C.

Description

[0001] Cross-reference of related applications

[0002] This application is a non-provisional application of U.S. Provisional Patent Application No. 63 / 234,288, filed August 18, 2021, and U.S. Provisional Patent Application No. 63 / 263,393, filed November 2, 2021, and claims priority to the aforementioned U.S. Provisional Patent Applications, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to apparatus and techniques for manufacturing organic emitting devices, such as organic light-emitting diodes, as well as apparatus and techniques including organic emitting devices. Background Technology

[0004] For many reasons, optoelectronic devices utilizing organic materials are becoming increasingly popular. Many of the materials used to manufacture these devices are relatively inexpensive, thus organic optoelectronic devices have the potential to offer a cost advantage over inorganic devices. Furthermore, the inherent properties of organic materials, such as their flexibility, make them more suitable for specific applications, such as fabrication on flexible substrates. Examples of organic optoelectronic devices include organic light-emitting diodes / devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials can exhibit performance advantages over conventional materials. For instance, the wavelength of light emitted by an organic emitting layer can often be easily tuned using appropriate dopants.

[0005] OLEDs utilize organic thin films that emit light when a voltage is applied to the device. OLEDs are becoming an increasingly popular technology for applications such as flat panel displays, lighting, and backlighting. Several OLED materials and configurations are described in U.S. Patent Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

[0006] One application of phosphorescent emitting molecules is in full-color displays. Industry standards for such displays require pixels suited to emitting specific colors (called "saturated" colors). Specifically, these standards require pixels saturated with red, green, and blue light. Alternatively, OLEDs can be designed to emit white light. In conventional liquid crystal displays, absorption filters are used to filter the emission from a white backlight to produce red, green, and blue emission. The same technology can be used for OLEDs. White OLEDs can be a single EML device or a stacked structure. Color can be measured using CIE coordinates, well-known in the field.

[0007] As used herein, the term "organic" includes both polymeric materials and small-molecule organic materials that can be used to manufacture organic optoelectronic devices. "Small molecule" refers to any organic material that is not a polymer, and "small molecule" can actually be quite large. In some cases, small molecules may include repeating units. For example, using long-chain alkyl groups as substituents does not remove the molecule from the "small molecule" category. Small molecules can also be incorporated into polymers, for example, as side groups on the polymer backbone or as part of the backbone. Small molecules can also serve as the core portion of dendritic polymers, which consist of a series of chemical shells built upon the core portion. The core portion of a dendritic polymer can be a fluorescent or phosphorescent small-molecule emitter. Dendritic polymers can be "small molecules," and all dendritic polymers currently used in the OLED field are considered small molecules.

[0008] As used herein, "top" means furthest from the substrate, and "bottom" means closest to the substrate. When the first layer is described as being "placed" "above" the second layer, the first layer is placed further away from the substrate. Unless specified that the first layer "contacts" the second layer, other layers may exist between the first and second layers. For example, even if various organic layers exist between the cathode and anode, the cathode may still be described as being "placed" "above" the anode.

[0009] As used herein, “solution-handleable” means capable of dissolving, dispersing or transporting in and / or depositing from a liquid medium in the form of a solution or suspension.

[0010] When a ligand is considered to directly contribute to the photosensitivity of the emissive material, the ligand may be referred to as "photosensitive." When a ligand is considered not to contribute to the photosensitivity of the emissive material, the ligand may be referred to as "auxiliary," but auxiliary ligands can alter the properties of photosensitizing ligands.

[0011] As used herein, and as will generally be understood by those skilled in the art, if the first energy level is closer to the vacuum level, then the first "Highest Occupied Molecular Orbital" (HOMO) or "Lowest Unoccupied Molecular Orbital" (LUMO) level is "greater than" or "higher than" the second HOMO or LUMO level. Since the ionization potential (IP) is measured as a negative energy relative to the vacuum level, a higher HOMO level corresponds to an IP with a smaller absolute value (less negative IP). Similarly, a higher LUMO level corresponds to an electron affinity (EA) with a smaller absolute value (less negative EA). On a conventional energy level diagram with the vacuum level at the top, the LUMO levels of a material are higher than the HOMO levels of the same material. "Higher" HOMO or LUMO levels appear to be closer to the top of this diagram than "lower" HOMO or LUMO levels.

[0012] As used herein, and as will generally be understood by those skilled in the art, if the first work function has a higher absolute value, then the first work function is “greater” or “higher” than the second work function. This is because the work function is typically measured as a negative number relative to the vacuum level, meaning that the “higher” work function is more negative. On a conventional energy level diagram with the vacuum level at the top, the “higher” work function is illustrated as being farther from the vacuum level in the downward direction. Therefore, the definitions of HOMO and LUMO levels follow different rules than those for the work function.

[0013] This document may describe layers, materials, regions, and devices by referring to the color of light emitted. Generally, as used herein, an emitting region that produces light of a particular color may include one or more emitting layers arranged in a stacked manner on top of each other.

[0014] As used herein, a "red" layer, material, region, or device refers to a layer, material, region, or device that emits light or whose emission spectrum has a peak in the range of about 580-700 nm. Similarly, a "green" layer, material, region, or device refers to a layer, material, region, or device that emits or has an emission spectrum with a peak wavelength in the range of about 500-600 nm; a "blue" layer, material, or device refers to a layer, material, or device that emits or has an emission spectrum with a peak wavelength in the range of about 400-500 nm; and a "yellow" layer, material, region, or device refers to a layer, material, region, or device with an emission spectrum with a peak wavelength in the range of about 540-600 nm. In some arrangements, individual regions, layers, materials, regions, or devices may provide separate "dark blue" and "light blue" light. As used herein, in an arrangement that provides separate "light blue" and "dark blue" components, the "dark blue" component refers to a component whose peak emission wavelength is at least about 4 nm smaller than the peak emission wavelength of the "light blue" component. Typically, the peak emission wavelength of the "light blue" component is in the range of approximately 465 nm to 500 nm, and the peak emission wavelength of the "dark blue" component is in the range of approximately 400 nm to 470 nm, although these ranges can vary for some configurations. Similarly, a color-changing layer refers to a layer that converts or modifies light of another color to have a wavelength specified for that color. For example, a "red" filter refers to a filter that forms light with wavelengths in the range of approximately 580-700 nm. Generally, there are two types of color-changing layers: filters that modify the spectrum by removing unwanted wavelengths of light, and color-changing layers that convert higher-energy photons into lower-energy ones. A "color" component refers to a component that, when activated or used, produces or otherwise emits light of a specific color as described above. For example, "a first emission region of a first color" and "a second emission region of a second color different from the first color" describe two emission regions that emit two different colors as described above when activated within the device.

[0015] As used herein, emitting materials, layers, and regions can be distinguished from each other and from other structures based on the light initially generated by said material, layer, or region, rather than by the light ultimately emitted by the same or different structures. Initial light generation is typically a result of energy level changes that lead to photon emission. For example, an organic emitting material can initially generate blue light, which can be converted into red or green light by a color filter, quantum dot, or other structure, causing the entire emitting stack or sub-pixel to emit red or green light. In this case, the initial emitting material or layer can be referred to as the "blue" component, even if the sub-pixel is a "red" or "green" component.

[0016] In some cases, the color of components, such as the color of emitting regions, subpixels, color-changing layers, etc., can preferably be described according to 1931 CIE coordinates. For example, a yellow emitting material may have multiple peak emission wavelengths, one in or near the edge of the "green" region and one in or near the edge of the "red" region, as previously described. Therefore, as used herein, each color item also corresponds to a shape in the 1931 CIE coordinate color space. The shape in the 1931 CIE color space is constructed by following the trajectory between two color points and any other interior points. For example, the interior shape parameters for red, green, blue, and yellow can be defined as follows:

[0017]

[0018] Further details about OLEDs and the definitions described above can be found in U.S. Patent No. 7,279,704, which is incorporated herein by reference in its entirety. Summary of the Invention

[0019] According to one embodiment, an organic light-emitting diode / device (OLED) is also provided. The OLED may include an anode, a cathode, and an organic layer disposed between the anode and the cathode. According to one embodiment, the organic light-emitting device is incorporated into one or more devices selected from consumer products, electronic component modules, and / or lighting panels.

[0020] In one embodiment, an organic vaporjet printing (OVJP) apparatus is provided, comprising an OVJP printhead including: a nozzle configured to eject organic material entrained by a carrier gas; a first heater disposed on a first side of the OVJP printhead; and a second heater disposed on a second side of the OVJP printhead, wherein the OVJP printhead is disposed between the first and second heaters. The OVJP printing apparatus may further include a first radiator disposed adjacent to and separated from the first heater via a first air gap, and a second radiator disposed adjacent to and separated from the second heater via a second air gap. The printhead may be surrounded by one or more bearings, such as gas bearings, plates, etc., which may be separated from the printhead via air gaps. The radiator may include a passively cooled radiator, such as a copper block or copper plate, and / or an actively cooled radiator, such as a water cooling circuit. The printhead including the radiator, heater, and nozzle may have a width not exceeding 15 mm, more preferably 10 mm, more preferably 5-6 mm, for example, in the printhead region extending through the gap in the bearing. The printhead can move independently of the heat sink, such that when the printhead moves, for example, in the vertical direction between the bearings, the heat sink remains stationary relative to other components and / or the deposition chamber. The printhead may also include multiple nozzles, heaters, and / or heat sinks, for example, in a linear or rectangular array. Similarly, the deposition system may include multiple printheads.

[0021] In one embodiment, a method of operating an OVJP printhead is provided, comprising: heating the printhead in a vacuum chamber to at least about 200-450°C; depositing material onto a substrate via the printhead; and removing sufficient heat from the local environment surrounding the printhead such that the operating ambient temperature of the vacuum chamber does not exceed 40°C. The heat may be removed via one or more heat sinks as described with respect to the printhead.

[0022] In one embodiment, an OVJP device is provided, comprising an OVJP printhead; and one or more heat sinks that are in thermal contact with the OVJP printhead and have heat removal capabilities sufficient to maintain an ambient temperature not exceeding 40°C when the printhead is operating at an operating temperature of 450°C. The heat sinks may include active cooling components, such as one or more water-cooled plates arranged adjacent to the printhead and separated from it via an air gap. Attached Figure Description

[0023] Figure 1 An organic light-emitting device that can be manufactured according to the system and techniques disclosed herein is shown.

[0024] Figure 2An inverted organic light-emitting device without individual electron transport layers is shown, which can be manufactured according to the systems and techniques disclosed herein.

[0025] Figure 3 This is a schematic diagram of the OVJP printing process.

[0026] Figure 4A and 4B A method for manufacturing a low-profile OVJP printhead according to an embodiment disclosed herein is shown.

[0027] Figure 5A A cross-sectional view of an OVJP die assembly according to an embodiment disclosed herein is shown, wherein heaters are located on both sides of the MEMS die.

[0028] Figure 5B The insertion of a gas bearing plate with thermal extraction features according to an embodiment disclosed herein is shown. Figure 5A The bare film assembly.

[0029] Figure 6 A low-profile printhead according to an embodiment disclosed herein is shown.

[0030] Figure 7 A printhead for use with a gas bearing according to an embodiment disclosed herein is shown.

[0031] Figure 8 An example embodiment of the printhead system disclosed herein is shown.

[0032] Figure 9 This illustrates a passively insulated printhead concept utilizing a metal-jacketed multilayer insulation, according to embodiments disclosed herein.

[0033] Figure 10 Examples of printheads and associated heating / cooling components according to embodiments disclosed herein are shown.

[0034] Figure 11 A schematic diagram of a hot gas pipeline and an insulating gas pipeline according to embodiments disclosed herein is shown. Detailed Implementation

[0035] Generally, an OLED comprises at least one organic layer disposed between and electrically connected to both the anode and cathode. When a current is applied, holes are injected into the anode and electrons into the organic layer from the cathode. The injected holes and electrons migrate toward their respective oppositely charged electrodes. When electrons and holes are localized on the same molecule, an "exciton" is formed, which is a localized electron-hole pair with an excited energy state. When the exciton relaxes through a photoemission mechanism, light is emitted. In some cases, excitons may be localized on excimers or excited-state complexes. Non-radiative mechanisms (such as thermal relaxation) may also occur, but are generally considered undesirable.

[0036] Early OLEDs used emitting molecules that emitted light from a single state (“fluorescence”), as disclosed, for example, in U.S. Patent No. 4,769,292, which is incorporated herein by reference in its entirety. Fluorescence emission typically occurs within timeframes of less than 10 nanoseconds.

[0037] Recently, OLEDs with emitting materials that emit light from the triplet state (“phosphorescence”) have been demonstrated. Baldo et al., “Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices,” Nature, Vol. 395, 151-154, 1998 (“Baldo-I”); and Baldo et al., “Very high-efficiency green organic light-emitting devices based on electrophosphorescence,” Applied Physics Letters, Vol. 75, 3, 4-6 (1999) (“Baldo-II”), are incorporated herein by reference in their entirety. Phosphorescence is described in more detail in columns 5-6 of U.S. Patent No. 7,279,704, which is incorporated herein by reference.

[0038] Figure 1An organic light-emitting device 100 is shown. The figures are not necessarily drawn to scale. Device 100 may include a substrate 110, an anode 115, a hole injection layer 120, a hole transport layer 125, an electron blocking layer 130, an emission layer 135, a hole blocking layer 140, an electron transport layer 145, an electron injection layer 150, a protective layer 155, a cathode 160, and a blocking layer 170. The cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. Device 100 can be fabricated by sequentially depositing the layers. The properties and functions of these various layers, as well as example materials, are described in more detail in columns 6-10 of US 7,279,704, which is incorporated herein by reference.

[0039] Further examples of each of these layers are available. For instance, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated herein by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ in a 50:1 molar ratio, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. Examples of emitting and host materials are disclosed in U.S. Patent No. 6,303,238 to Thompson et al., which is incorporated herein by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li in a 1:1 molar ratio, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. Examples of cathodes, comprising composite cathodes having a thin layer of metal (e.g., Mg:Ag) having an overlying transparent, conductive, sputtered ITO layer, are disclosed in their entirety in U.S. Patent Nos. 5,703,436 and 5,707,745, which are incorporated herein by reference in their entirety. Theories and uses of barrier layers are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, which are incorporated herein by reference in their entirety. Examples of implantation layers are provided in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated herein by reference in its entirety. Descriptions of protective layers can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated herein by reference in its entirety.

[0040] Figure 2An inverted OLED 200 is shown. The device includes a substrate 210, a cathode 215, an emitter layer 220, a hole transport layer 225, and an anode 230. The device 200 can be fabricated by sequentially depositing these layers. Because the most common OLED configuration has a cathode disposed above the anode, and the device 200 has a cathode 215 disposed below the anode 230, the device 200 can be referred to as an "inverted" OLED. Materials similar to those described with respect to device 100 can be used in the corresponding layers of the device 200. Figure 2 Provide an example of how some layers can be omitted from the structure of device 100.

[0041] Figure 1 and 2 The simple layered structures illustrated herein are provided by way of non-limiting examples, and it should be understood that embodiments of the invention can be used in conjunction with a variety of other structures. The specific materials and structures described are exemplary in nature, and other materials and structures can be used. Functional OLEDs can be obtained by combining the various layers described in different ways, or the layers can be omitted entirely based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many examples provided herein describe various layers as comprising a single material, it should be understood that combinations of materials, such as mixtures of host and dopant, or more generally, mixtures, can be used. Furthermore, the layers may have various sublayers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, hole transport layer 225 transports holes and injects holes into emitter layer 220, and can be described as a hole transport layer or a hole injection layer. In one embodiment, an OLED may be described as having an “organic layer” disposed between a cathode and an anode. This organic layer may comprise a single layer, or may further comprise, for example, regarding Figure 1 and 2 Multiple layers of the different organic materials mentioned above.

[0042] Structures and materials not specifically described can also be used, such as OLEDs (PLEDs) containing polymeric materials, as disclosed in, for example, U.S. Patent No. 5,247,190 to Friend et al., which is incorporated herein by reference in its entirety. By another example, OLEDs with a single organic layer can be used. OLEDs can be stacked, for example, as described in, U.S. Patent No. 5,707,745 to Forrest et al., which is incorporated herein by reference in its entirety. OLED structures can be deviated from... Figure 1 and 2The simple layered structure described herein. For example, the substrate may include angled reflective surfaces to improve out-coupling, such as the tabletop structure described in U.S. Patent No. 6,091,195 to Forrest et al., and / or the recessed structure described in U.S. Patent No. 5,834,893 to Bulovic et al., which are incorporated herein by reference in their entirety.

[0043] In some embodiments disclosed herein, the emission layer or material, for example Figure 1-2 The emitting layers 135 and 220 shown herein may include quantum dots. Unless explicitly indicated otherwise or as understood by one of ordinary skill in the art, the term "emitting layer" or "emitting material" as disclosed herein may include organic emitting materials and / or emitting materials containing quantum dots or equivalent structures. Such emitting layers may consist only of quantum dot materials that convert light emitted by a separate emitting material or other emitting entity, or may also include a separate emitting material or other emitting entity, or may emit light directly by the application of an electric current. Similarly, color-changing layers, color filters, up-conversion or down-conversion layers or structures may include materials containing quantum dots, but such layers are not considered "emitting layers" as disclosed herein. Typically, an "emitting layer" or material is a material that emits initial light, which may be altered by another layer, such as a color filter or other color-changing layer, that does not itself emit the initial light within the device but may re-emit altered light with different spectral content based on the initial light emitted by the emitting layer.

[0044] Unless otherwise specified, any of the layers in the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include thermal evaporation, inkjet printing (as described in U.S. Patent Nos. 6,013,982 and 6,087,196, which are incorporated herein by reference in their entirety), organic vapor deposition (OVPD) (as described in U.S. Patent No. 6,337,102 by Forrest et al., which are incorporated herein by reference in their entirety), and deposition by organic vapor jet printing (OVJP) (as described in U.S. Patent No. 7,431,968, which is incorporated herein by reference in its entirety). Other suitable deposition methods include spin coating and other solution-based processes. Solution-based processes are preferably performed in a nitrogen or inert atmosphere. For other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition via a mask, cold soldering (as described in U.S. Patents 6,294,398 and 6,468,819, which are incorporated herein by reference in their entirety), and patterning associated with some of the deposition methods such as inkjet and OVJD. Other methods may also be used. The material to be deposited may be modified to suit a particular deposition method. For example, branched or unbranched substituents, preferably containing at least three carbons, such as alkyl and aryl groups, may be used in small molecules to enhance their solution handling ability. Substituents having 20 or more carbons may be used, with 3 to 20 carbons being a preferred range. Materials with asymmetric structures may have better solution handleability than those with symmetric structures because asymmetric materials may have a lower tendency to recrystallize. Dendritic polymer substituents may be used to enhance the solution handling ability of small molecules.

[0045] Devices manufactured according to embodiments of the present invention may optionally further include a barrier layer. One use of the barrier layer is to protect the electrodes and organic layers from damage caused by exposure to harmful substances in an environment including moisture, vapor, and / or gases. The barrier layer may be deposited on, under, or beside a substrate or electrode, or on any other part of the device, including edges. The barrier layer may comprise a single layer or multiple layers. The barrier layer can be formed using various known chemical vapor deposition techniques and may comprise compositions having a single phase and compositions having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may contain inorganic or organic compounds, or both. Preferred barrier layers comprise a mixture of polymeric and non-polymeric materials, as described in U.S. Patent No. 7,968,146, PCT Patent Application Nos. PCT / US2007 / 023098 and PCT / US2009 / 042829, which are incorporated herein by reference in their entirety. For the process to be considered a "mixture," the aforementioned polymeric and non-polymeric materials constituting the barrier layer should be deposited and / or deposited simultaneously under the same reaction conditions. The weight ratio of polymeric to non-polymeric materials can range from 95:5 to 5:95. The polymeric and non-polymeric materials can be produced from the same precursor material. In one example, the mixture of polymeric and non-polymeric materials is essentially composed of polymeric silicon and inorganic silicon.

[0046] In some embodiments, at least one of the anode, cathode, or a new layer disposed above the organic emitter layer serves as a reinforcement layer. The reinforcement layer comprises a plasmonic material exhibiting surface plasmon resonance, which is nonradiatively coupled to the emitter material and transfers excited-state energy from the emitter material to the nonradiative mode of the surface plasmon polariton. The reinforcement layer is provided at a threshold distance not exceeding that of the organic emitter layer, wherein the emitter material has a total nonradiative decay rate constant and a total radiative decay rate constant due to the presence of the reinforcement layer, and the threshold distance is a distance where the total nonradiative decay rate constant is equal to the total radiative decay rate constant. In some embodiments, the OLED further comprises an decoupling layer. In some embodiments, the decoupling layer is disposed above the reinforcement layer on the opposite side of the organic emitter layer. In some embodiments, the decoupling layer is disposed on the opposite side of the emitter layer to the reinforcement layer, but still allows energy to be decoupled from the surface plasmon polariton modes of the reinforcement layer. The decoupling layer scatters energy from the surface plasmon polariton. In some embodiments, this energy is scattered into free space in the form of photons. In other embodiments, energy is scattered from the surface plasmon modes of the device into other modes, such as, but not limited to, organic waveguide modes, substrate modes, or another waveguide mode. If energy is scattered into the non-free-space modes of the OLED, other decoupling schemes can be incorporated to extract the energy into free space. In some embodiments, one or more intervention layers may be disposed between the enhancement layer and the decoupling layer. Examples of intervention layers may be dielectric materials, including organic, inorganic, perovskite, and oxide materials, and may include stacks and / or mixtures of these materials.

[0047] The enhancement layer modifies the effective properties of the medium in which the emitter material resides, thereby causing any or all of the following: reduced emissivity, modification of emission spectral shape, changes in emission intensity and angle, changes in the stability of the emitter material, changes in OLED efficiency, and reduced efficiency degradation of the OLED device. Placing the enhancement layer on the cathode side, anode side, or both sides produces an OLED device that utilizes any of the above effects. In addition to the specific functional layers mentioned herein and illustrated in the various OLED examples shown in the figures, the OLED according to the invention may also include any of the other functional layers commonly found in OLEDs.

[0048] The reinforcing layer can be composed of plasmonic materials, optically active metamaterials, or hyperbolic metamaterials. As used herein, plasmonic materials are materials whose real portion of the dielectric constant crosses zero in the visible or ultraviolet region of the electromagnetic spectrum. In some embodiments, the plasmonic material comprises at least one metal. In such embodiments, the metal may include at least one of the following: Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca, alloys or mixtures of these materials, and stacks of these materials. Generally, metamaterials are media composed of different materials, wherein the medium as a whole acts differently than the sum of its material parts. Specifically, we define optically active metamaterials as materials having both a negative dielectric constant and negative permeability. On the other hand, hyperbolic metamaterials are anisotropic media, wherein the permittivity or permeability has different signs for different spatial orientations. Optically active metamaterials and hyperbolic metamaterials are strictly distinguished from many other photonic structures, such as distributed Bragg reflectors (DBRs), because the medium must be uniform along the length scale of the light wavelength in the direction of propagation. Using terminology understood by those skilled in the art, the dielectric constant of the metamaterial in the direction of propagation can be approximated by an effective medium. Plasmon materials and metamaterials offer methods for controlling light propagation that can enhance OLED performance in a variety of ways.

[0049] In some embodiments, the enhancement layer is provided as a planar layer. In other embodiments, the enhancement layer has wavelength-sized features arranged periodically, quasi-periodicly, or randomly, or subwavelength-sized features arranged periodically, quasi-periodicly, or randomly. In some embodiments, the wavelength-sized features and subwavelength-sized features have sharp edges.

[0050] In some embodiments, the decoupling layer is characterized by a wavelength size arranged periodically, quasi-periodicly, or randomly, or by a subwavelength size arranged periodically, quasi-periodicly, or randomly. In some embodiments, the decoupling layer may be composed of a plurality of nanoparticles, and in other embodiments, the decoupling layer is composed of a plurality of nanoparticles disposed on a material. In these embodiments, decoupling can be tuned by at least one of the following: changing the size of the plurality of nanoparticles, changing the shape of the plurality of nanoparticles, changing the material of the plurality of nanoparticles, adjusting the thickness of the material, changing the refractive index of the material or an additional layer disposed on the plurality of nanoparticles, changing the thickness of the reinforcing layer, and / or changing the material of the reinforcing layer. The plurality of nanoparticles of the device may be formed from at least one of the following: a metal, a dielectric material, a semiconductor material, a metal alloy, a mixture of dielectric materials, a stack or layer of one or more materials, and / or a core of one type of material, wherein the core is coated with a shell of a different type of material. In some embodiments, the decoupling layer is composed of at least metal nanoparticles, wherein the metal is selected from the group consisting of: Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca, alloys or mixtures of these materials, and stacks of these materials. Multiple nanoparticles may have additional layers disposed on them. In some embodiments, the polarization of the emission can be tuned using the decoupling layer. Changing the dimension and periodicity of the decoupling layer can select a type of polarization that preferentially decouples to air. In some embodiments, the decoupling layer also functions as an electrode of the device.

[0051] It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistical limit through delayed fluorescence. As used in this paper, there are two types of delayed fluorescence: P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence is generated by triplet-triplet annihilation (TTA).

[0052] On the other hand, E-type delayed fluorescence does not depend on the collision of two triplet states, but rather on the thermal population between the triplet and singlet excited states. Compounds capable of producing E-type delayed fluorescence are required to have a very small singlet-triplet gap. Thermal energy can activate transitions from the triplet state back to the singlet state. This type of delayed fluorescence is also called thermally activated delayed fluorescence (TADF). A significant characteristic of TADF is that the delayed component increases with increasing temperature due to increased thermal energy. If the reverse intersystem crossing rate is fast enough to minimize nonradiative decay from the triplet state, the fraction of singlet excited states that are refilled can reach 75%. The total singlet fraction can be 100%, far exceeding the spin statistical limit of electrically generated excitons.

[0053] E-type delayed fluorescence can be observed in excited complex systems or single compounds. Unbound by theory, it is believed that E-type delayed fluorescence requires the luminescent material to have a small singlet-triplet band gap (ΔES-T). Organic, metal-free donor-acceptor luminescent materials may be able to achieve this. The emission of these materials is typically characterized by donor-acceptor charge transfer (CT) emission. Spatial separation of the HOMO and LUMO in these donor-acceptor compounds usually results in a small ΔES-T. These states may involve CT states. Typically, donor-acceptor luminescent materials are constructed by linking an electron donor moiety (e.g., an amino or carbazole derivative) with an electron acceptor moiety (e.g., an N-containing six-membered aromatic ring).

[0054] Devices manufactured according to embodiments of the present invention can be incorporated into a wide variety of electronic component modules (or units), which can be incorporated into a variety of electronic products or intermediate components. Examples of such electronic products or intermediate components include displays, lighting devices (such as discrete light source devices or lighting panels), etc., which can be utilized by end-user product manufacturers. The electronic component module may optionally include driving electronics and / or a power supply. Devices manufactured according to embodiments of the present invention can be incorporated into a wide variety of consumer products having one or more electronic component modules (or units) incorporated therein. A consumer product incorporating an OLED is disclosed, wherein the OLED comprises compounds of the present disclosure in its organic layer. The consumer product should include any type of product containing one or more light sources and / or one or more of some type of visual display. Examples of the consumer products described include flat panel displays, curved displays, computer monitors, medical monitors, televisions, billboards, lights for internal or external lighting and / or signaling, head-up displays, fully transparent or partially transparent displays, flexible displays, rollable displays, foldable displays, stretchable displays, laser printers, telephones, cellular phones, tablet computers, phablets, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, camcorders, viewfinders, microdisplays with a diagonal of less than 2 inches, 3D displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple tiled displays, theater or stadium screens, and signage. Various control mechanisms, including passive and active matrices, can be used to control the devices manufactured according to the invention. Many of the devices are intended for use in temperature ranges comfortable for humans, such as 18°C ​​to 30°C, and more preferably at room temperature (20-25°C), but can be used outside this temperature range (e.g., -40°C to 80°C).

[0055] The materials and structures described herein can be applied to devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can utilize the materials and structures described herein. More generally, organic devices such as organic transistors can utilize the materials and structures described herein.

[0056] In some embodiments, the OLED has one or more features selected from the group consisting of: flexible, rollable, foldable, stretchable, and bendable. In some embodiments, the OLED is transparent or translucent. In some embodiments, the OLED further comprises a layer including carbon nanotubes.

[0057] In some embodiments, the OLED further comprises a layer including a delayed phosphor emitter. In some embodiments, the OLED comprises an RGB pixel arrangement or a white pixel arrangement with a color filter. In some embodiments, the OLED is a mobile device, a handheld device, or a wearable device. In some embodiments, the OLED is a display panel with a diagonal of less than 10 inches or an area of ​​less than 50 square inches. In some embodiments, the OLED is a display panel with a diagonal of at least 10 inches or an area of ​​at least 50 square inches. In some embodiments, the OLED is a lighting panel.

[0058] In some embodiments of the launch area, the launch area further includes a body.

[0059] In some embodiments, the compound may be an emission dopant. In some embodiments, the compound may generate emission via phosphorescence, fluorescence, thermally activated delayed fluorescence (TADF, also known as E-type delayed fluorescence), triplet-triplet annihilation, or a combination of these processes.

[0060] The OLEDs disclosed herein can be incorporated into one or more consumer products, electronic component modules, and lighting panels. The organic layer can be an emission layer, and the compound can be an emission dopant in some embodiments, while in other embodiments it can be a non-emission dopant.

[0061] The organic layer may also include a host. In some embodiments, two or more hosts are preferred. In some embodiments, the host used may be a) bipolar, b) electron transport, c) hole transport, or d) wide-bandgap material that plays a minor role in charge transport. In some embodiments, the host may include a metal complex. The host may be an inorganic compound.

[0062] Combination with other materials

[0063] The materials described herein for use in specific layers of organic light-emitting devices can be used in combination with a wide variety of other materials present in the device. For example, the emission dopants disclosed herein can be used in combination with a wide variety of possible host layers, transport layers, blocking layers, injection layers, electrodes, and other layers. The materials described or mentioned below are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and those skilled in the art can readily consult the literature to identify other materials that can be used in combination.

[0064] The various emitting and non-emitting layers and arrangements disclosed herein can be made of different materials. Examples of suitable materials are disclosed in U.S. Patent Application Publication No. 2017 / 0229663, which is incorporated herein by reference in its entirety.

[0065] Conductive dopants:

[0066] Charge transport layers can be doped with conductive dopants to substantially alter their charge carrier density, which in turn changes their conductivity. Conductivity is increased by creating charge carriers in the matrix material and, depending on the type of dopant, can also achieve changes in the Fermi level of the semiconductor. Hole transport layers can be doped with p-type conductive dopants, while n-type conductive dopants are used in electron transport layers.

[0067] HIL / HTL:

[0068] The hole injection / transport materials used in this invention are not particularly limited, and any compound can be used, as long as the compound is commonly used as a hole injection / transport material.

[0069] EBL:

[0070] An electron blocking layer (EBL) can be used to reduce the number of electrons and / or excitons leaving the emitter layer. The presence of such a blocking layer in a device can result in generally higher efficiency and / or longer lifetime compared to similar devices lacking a blocking layer. Furthermore, the blocking layer can be used to confine emission to a desired area of ​​the OLED. In some embodiments, the EBL material has a higher LUMO (closer to vacuum level) and / or higher triplet energy compared to the emitter closest to the EBL interface. In some embodiments, the EBL material has a higher LUMO and / or higher triplet energy compared to one or more of the bodies closest to the EBL interface. In one aspect, the compound used in the EBL contains the same molecules or the same functional groups as those used in one of the bodies described below.

[0071] main body:

[0072] The light-emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as the light-emitting material, and may contain a host material using a metal complex as a dopant material. Examples of the host material are not particularly limited, and any metal complex or organic compound can be used, as long as the triplet energy of the host is greater than that of the dopant. Any host material can be used with any dopant, as long as the triplet criterion is satisfied.

[0073] HBL:

[0074] Hole blocking layers (HBLs) can be used to reduce the number of holes and / or excitons leaving the emitter layer. The presence of such blocking layers in a device can result in generally higher efficiency and / or longer lifetime compared to similar devices lacking a blocking layer. Furthermore, blocking layers can be used to confine emission to a desired area of ​​the OLED. In some embodiments, the HBL material has a lower HOMO (farthest from vacuum level) and / or higher triplet energy compared to the emitter closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO and / or higher triplet energy compared to one or more of the bodies closest to the HBL interface.

[0075] ETL:

[0076] An electron transport layer (ETL) may comprise a material capable of transporting electrons. The ETL may be intrinsic (undoped) or doped. Doping can be used to enhance conductivity. Examples of ETL materials are not particularly limited, and any metal complex or organic compound may be used, provided it is typically used for electron transport.

[0077] Charge generation layer (CGL)

[0078] In tandem or stacked OLEDs, the conduction layer (CGL) plays a fundamental role in performance. It consists of an n-doped layer and a p-doped layer, respectively, for injecting electrons and holes. Electrons and holes are supplied by the CGL and the electrodes. Electrons and holes consumed in the CGL are refilled by electrons and holes injected from the cathode and anode, respectively; subsequently, the bipolar current gradually reaches a steady state. Typical CGL materials include n- and p-conductive dopants used in the transport layer.

[0079] As previously disclosed, organic vapor jet printing (OVJP) is a technique for printing intricate lines of organic material onto display backplanes without using fine metal shadow masks or liquid solvents, such as for OLEDs and other devices. Current conventional techniques for manufacturing mobile and laptop displays typically utilize evaporation sources and fine metal shadow masks to pattern the deposition. However, fine metal shadow masks are unsuitable for manufacturing large-area displays because they cannot be stretched with sufficient force to prevent sagging.

[0080] Inkjet printing is a potential patterning technique for OLED displays, but the use of liquid solvents to manufacture inks severely degrades the performance of the light-emitting device. The OVJP technology disclosed herein overcomes both of these problems by printing pixel-width OLED material lines without using fine metal masks and by utilizing existing OLED materials without dissolving them in solvents.

[0081] In OVJP technology, OLED materials are heated to an elevated sublimation temperature in a closed container and delivered to the printhead via a hot gas pipeline using an inert carrier gas. Figure 3 This is a schematic diagram of the OVJP printing process, showing the basic components of the process. The printhead 3040 contains jet holes 3050, the spacing of which corresponds to the pixel pitch of the display. Holes can be formed in a silicon wafer using standard MEMS manufacturing techniques, and a functional OVJP die is cut from the wafer, the holes existing along one surface of the die. Organic material 3010 can be delivered to the die in a saturated vapor stream 3030 at high temperature, and excess organic material is removed from the printing area using vacuum channels created in the printed die. The hole surface of the die is positioned above a mobile display backplane, and lines corresponding to the pixels are printed on the backplane 3070.

[0082] The gap between the printed die and the backing substrate surface can be accurately controlled by measuring the gap in real time and moving the printhead relative to the backing substrate surface. The OVJP deposition rate varies with the gap between the substrate and the printed die. To achieve the required thickness uniformity of better than 98% (thickness non-uniformity <2%), the gap should be controlled within + / - 2 μm. When the flatness of the glass substrate along the length of the printed die is less than 1 μm, gap control can be straightforward. The glass surface can be flattened using a pair of flat gas bearings (a soft bearing below the glass to float the substrate, and a harder bearing above the glass to flatten the glass). This configuration is for a system where the active glass surface is facing upwards during printing. If the printed surface is facing downwards, the lower gas bearing is the harder bearing.

[0083] One method to improve glass flatness is to use two opposing flat gas bearings, with the glass positioned between the bearings. One bearing adjacent to the back of the glass is a soft bearing, while the bearing adjacent to the front or printed surface of the glass is a hard bearing. The hard bearing causes the glass to bend to take the shape of the top bearing. If the top bearing is flat, the top surface of the glass will be flat. When used in an OVJP system, the hard bearing may include a port for the OVJP printhead. Advantageously, the port can be narrow so that the bearing provides the most flattening force. The thermal printhead heats the hard bearing plate around the periphery of the port, causing the bearing plate to warp and reducing the flatness of the plate and the glass substrate. The embodiments disclosed herein eliminate or significantly reduce heat transfer from the thermal printhead to the bearing plate.

[0084] As previously disclosed, it is preferable that the slot of the harder gas bearing penetrating the printhead be as narrow as possible to maximize the planarization effect of the gas bearing. In one embodiment, no pressure is applied to the glass in the slot region and the planarization effect of the bearing is reduced.

[0085] Narrow slots may require, for example Figure 4A and 4BThe narrow printhead 2010 is shown. The printhead 2010 can be made of a metal that closely matches the silicon die using a CTE, such as tungsten or molybdenum, or ceramic, such as aluminum nitride bonded to the silicon die 2040. For example, the gas manifold and hot surface of the printhead can be made of tungsten metal, and another metal or ceramic can also be used. Two tungsten plates 2100 and 2110, having surfaces “A” 2120, “B” 2130, “C” 2130, and “D” 2140, are etched or machined to have channels or through-holes in their surfaces. Surface “A” has two sets of through-holes 2200 and 2210, which are machined to half the thickness of the entire plate. The opposite surface “B” 2120 has two sets of channels 2220 and 2230, which are ground in the surface to slightly exceed half the thickness of the entire plate, such that the channels intersect with the through-holes in surface “A”. The second plate 2110 has a channel on surface "C" 2130 that matches the channel in surface "B", and surface "D" 2140 has two slotted through-holes 2260 and 2270, which are ground into the plate to intersect with the two sets of channels 2220 and 2230. Through-holes 2260 and 2270 match through-holes on surface "E" 2150 of the OVJP printed die. The tungsten plates can be soldered or brazed together with faces "B" and "C" facing inwards, such that the ground channels form a gas path from the injection block 2020 to the printed die 2040. The silicon printed die is attached to the tungsten manifold by soldering, glass bonding, or another attachment member. This assembly produces a narrow printed die assembly 2010. The tungsten plates and injection block are heated using resistance heaters (not shown) attached to their outer surfaces. In some cases, an external heater may not be required. For example, in the case of an aluminum nitride gas manifold, the heater can be incorporated as part of the gas manifold and no external heater is required.

[0086] Figure 5A It showed something similar to Figures 4A to 4B The narrow printhead 2010 shown includes another back heater 306 to heat the back side of the die 2040. This die assembly can be attached to the injection block 2020 using, for example, a C-ring 305 and bolts 304. The back heater in this example is made of AlN-tungsten composite material. Figure 5BA narrow printhead and a back heater are shown, integrally mounted with cooling jackets 310 and 311, through a flat air bearing 313. The cooling jacket may be constructed of a high thermal conductivity metal (e.g., copper) and is cooled by allowing fluid (e.g., water) to flow through an integral channel 312 machined within the jacket. A low thermal conductivity mounting fixture 314 can be used to attach the cooling jacket to the gas bearing in a manner that the cooling jacket temperature does not alter the gas bearing temperature. Heat transfer between the thermal printhead and the cooling jacket, and between the cooling jacket and the gas bearing, is minimized using an air gap 315. The cooling jacket extends to the top of the printhead to prevent the structure supporting the printhead assembly from overheating.

[0087] Figure 6 A similar printhead configuration is shown, but the MEMS die is sealed using compression rather than by bonding to a gas manifold. In this example, a micronozzle array 401 is used, which may resemble a micronozzle array with a plane orthogonal to its orifice and may have one or more delivery orifices in fluid communication with the flow of inert carrier gas and organic vapors. Each side of the delivery orifice may be an exhaust orifice in fluid communication with an exhaust line. The micronozzle array 401 may be disposed at the edge of a silicon die 402 disposed between plates 403. Plate 403 may include a first gas distribution plate and a second opposing plate. The micronozzle array 401, silicon die 402, and plates 403 may extend through a cold plate 404. The micronozzle array 401 may be close to the substrate 410 where targeted deposition will be performed. The die 402 may be irreversibly sealed to one or more of the gas distribution plate and the opposing plate using methods such as glass frit, ceramic adhesive, bonding, soldering, or brazing. In some embodiments, the die 402 may be attached to the gas distribution plate. The gas distribution plate in plate 403 can be mechanically attached to the interfaced manifold block 405, and one or more fluid paths 406 can be sealed using a high-temperature seal in the gland component 407. At least one plate 403 has a channel 408 that feeds organic vapors entrained by an inert carrier gas from a manifold connected to one or more organic vapor sublimation sources 411 into the bare sheet 402. At least one plate 403 may include an exhaust line 409 that connects a through-hole on the bare sheet 402 to a low-pressure reservoir 412 to draw back the processed gas and residual organic vapors from the printed area. As shown, the organic vapor channel 408 and the exhaust line 409 may be drawn through the same plate 403. Opposite plates 403a and manifold block 405a may not include any internal channels, and therefore no airtight seal may be used at their interface. Figure 7 It shows the extension through the upper gas bearing, such as Figures 4A to 5AThe printhead shown has been modified to partially replace the gas bearing vacuum flow with a printed die vacuum flow. For mechanical clearance and to prevent overheating of the gas bearing 509, an air gap 514 may be provided on each side of the printhead 2010. Pressure holes 510 and vacuum holes 511 may be staggered in directions parallel and perpendicular to the slots cut into the gas bearing plate. This arrangement allows for a wider pick-up channel formed in the gas bearing while maintaining glass planarization properties.

[0088] Figures 3 to 7 The apparatus shown may include a “printer” or “print bar” which may include multiple print heads. The OVJP deposition apparatus and system disclosed herein are applicable to any such system, as will be readily understood by one of skill in the art.

[0089] Figure 8 An example OVJP apparatus as disclosed herein is shown. The apparatus includes an OVJP nozzle (“printing die”) 810 as previously disclosed, which is partially or completely surrounded by one or more heaters 820 on either side of the nozzle. During operation, the heaters 820 can be used to maintain the printing die 810 at a desired temperature, typically in the range of 200 to 450°C. The heaters 820 can be, for example, aluminum nitride (AlN) heaters. An air gap 830 separates the heaters from one or more heat sinks 840 located on the opposite side of the nozzle. The heat sinks can be, for example, water-cooled copper heat sinks. One or more bearings 850, such as air or other gas bearings, plates, etc., disposed externally on the heat sink 840, can be used to support the printhead. The bearings can be separated from the printhead assembly and the heat sink 840 by one or more additional air gaps 852 surrounding the heat sink 840, or the bearings can be connected to the heat sink, for example via a metal or other connector having a relatively low thermal conductivity (e.g., 15 W / mK or less). As disclosed in conjunction with the previous arrangement, the printhead may extend through a narrow opening in the bearing 850 and may include channels and through-holes as previously described, such as channels and through-holes for conveying organic materials entrained in the carrier gas, which are ejected from the nozzle through the printhead.

[0090] Radiators can provide active or passive cooling, or a combination thereof. For example, one or more radiators may include passive components, such as a block or plate made of copper or a similar material known to provide good thermal conductivity and heat dissipation. One or more radiators may also include active components, such as water circulation and / or cooling systems that move water or other cooling fluids through the radiator to remove heat using the radiator.

[0091] Other arrangements of the heatsink assembly can be used. For example, Figure 9An alternative version of the printhead disclosed herein is shown, wherein active water cooling is replaced by a metal-jacketed, multi-layered, high-performance insulation. This insulation may be jacketed within a hermetically sealed metal container to remove escaping gas from the deposition chamber, particularly in deposition chambers where deposition is performed under vacuum. The insulation may be attached to the printhead 900, whose structure may be the same as or similar to that previously described in conjunction with Figures 4 to 9, such that the insulation moves with the printhead as it moves longitudinally within the channels between bearings 913, or the insulation may be fixed relative to the printhead. Insulations 910, 911, 912, and 914 may be separated from the printhead 700 and bearing plate 913 by an air gap 915.

[0092] A combined nozzle structure, including a radiator, heater, and nozzle, can be relatively small, thus requiring a relatively small opening between the bearings. For example, the maximum horizontal width of the nozzle, surrounding heater, and surrounding radiator may not exceed 15 mm, more preferably 10 mm, and even more preferably 5-6 mm. The maximum horizontal width of the combined nozzle structure refers to the maximum measured value across the nozzle in a direction parallel or substantially parallel to the intended position of the substrate below the nozzle, from the outer edge to the outer edge. Figure 8 The distance x 890 is shown in the diagram. The radiator may include passive and / or active cooling components that extend outward by a distance greater than this maximum horizontal width of the area detached from bearing 850, for example, extending outward in region 895. Such extension may be used to provide additional space, for example, for cooling components (e.g., water channels and connections).

[0093] The printhead and / or heater can move independently of the heat sink within the area between the heat sinks. That is, while the printhead 810 and / or heater 820 move longitudinally within the area between the heat sinks, the heat sink 840 can remain fixed relative to the bearing 850, the deposition chamber, or other components of the system.

[0094] Another way to improve glass substrate flatness, as disclosed herein, is through a gas stage, in which, in a system with the active side facing up, a pre-loaded vacuum bearing or pressure vacuum (PV) bearing is located on the back side of the substrate. This arrangement typically improves control over the gap between the stage and the substrate and stiffens the bearing. This method, in principle, eliminates the need for a top bearing for glass planarization. Therefore, the printhead assembly does not require, as previously discussed, for example... Figure 8 As disclosed, it mates with a through-slot, and the width requirement may be somewhat lenient. Examples of such arrangements are shown in Figure 10As previously disclosed, a gas line 1080 may introduce a hot carrier gas containing organic material to be deposited onto a substrate by a printed die 810. The gas line may be enclosed in an insulating material or other heat shield 1090. The spacing between the printed die 810 and the substrate may be controlled using a flight actuator 1020 (e.g., one or more voice coils, piezoelectric electrodes, etc.). The flight actuator 1020 may receive data from a flight altitude sensor 1010 that measures the substrate-die spacing and may also sense the position of the printed die 810 relative to the substrate. The printed die 810 may be enclosed or otherwise surrounded in an actively cooled heat shield 1030, such as the previously described heat sink 840, and / or other arrangements disclosed herein. An air gap may also be used to separate the printed die 810 from other components of the system and prevent those components from being heated, as previously disclosed.

[0095] Although this configuration lacks a top bearing to prevent deformation from the heat generated by the printed die, it is still necessary to minimize the impact of the heat generated by the printed die on the rest of the system. Specifically, temperature-sensitive components such as the flight altitude sensor 1010 and flight control actuator 1020 are susceptible to damage from high temperatures (e.g., 30°C) and therefore the heat generated by the printhead 810 should be shielded. Additionally, to minimize any resulting thermal expansion, the impact of the heat generated by the printhead 810 on the surrounding structure supporting it should be kept as small as possible, as this could lead to misalignment between the print nozzles and the pixel structure on the glass substrate. The thermal expansion of the printhead itself is accommodated by a set of identical flexible elements equidistant from the center of the printhead; the printhead is designed with the thermal expansion of the die in mind. Ultimately, the heat generated by the printed die 810 can cause deformation of the glass substrate (specifically, upward bending), which in turn can cause undesirable changes in flight altitude. Therefore, this heat should also be shielded from the glass as much as possible without obstructing gas flow to and from the die 810.

[0096] Examples of suitable heat shielding solutions include a heat shield 1030 that surrounds the vertical surface of the printhead 810 on some or all sides. Such a heat shield can be made of various types of insulation materials, such as multilayer insulation and ceramic fiber materials, and may include a thermally conductive material (e.g., copper) plate with embedded channels for the flow of cooling fluid (e.g., water). An active cooling heat-conducting plate, as thin as 1 mm, acts as a cooling jacket thermally isolating the top bearing from the printhead and allows safe contact with the outer surface of the heat shield, enabling flight altitude sensor adjustment and other maneuvers while the printhead is hot, and minimizing or reducing thermal expansion of the structure supporting the printhead. The interior of the heat shield may be coated with a reflective layer, such as Ni or Al, to minimize heat radiated from the printhead. Additionally, the heat shield 1030 itself may be separated from the printhead 810 by a gap (typically at least 1 mm) to minimize conductive / convective heat transfer.

[0097] In addition to the heat shield surrounding the vertical surface of the printhead, the heat shielding scheme may also include a section 1050 positioned above the printhead 810 to further protect the flight control actuator 1020. The basic structure of the top section 1050 may be the same as that of the heat shield 1030, such as an insulating plate or a plate with embedded fluid cooling channels. Preferably, the top section 1050 includes a top cooling plate positioned above a flexible element that allows the printhead to expand as it heats up, so that it does not have to accommodate the expansion. A bottom "cold" plate 1060, which surrounds the printed die and faces the substrate at a distance of up to about 0.5 mm, may be used to further reduce the effect of heat generated by the printhead 810 on the glass substrate. The cold plate 1060 may be connected to the bottom of the heat shield surrounding the printhead 810 and may also contain embedded channels for the flow of cooling fluid, as well as inlet and outlet manifolds 1070 for the cooling fluid.

[0098] In addition to the printhead itself being supplied and vented by gas via pipeline 1080, the printhead 810 also needs to be heated (to prevent OLED material from condensing in these pipelines). As in the case of the printhead, the rest of the system must shield this heat. In principle, a solution similar to that used for the printhead, as shown in 1090, could be used. However, the desire or need to integrate the heater and maintain a small footprint may make an active cooling solution somewhat impractical. Figure 11 A schematic diagram of a gas pipeline is shown, employing an alternative, more compact heating and insulation solution. In this arrangement, one or more vacuum gaps or vacuum jackets 1101 are positioned between an inner thermal liner 1102 and an outer thermally conductive shell 1103. The inner thermal liner may include, for example, heat-conducting pipes connected to a heater. The vacuum jacket 1101 minimizes thermal losses of the outer shell 1103 of the gas pipeline 1080. The shell can then be thermally connected to a printhead heat shield to maintain the shell at a safe temperature.

[0099] In some embodiments, the printhead may include multiple nozzles, heaters, and / or heat sinks. For example, in some cases, an array of two or more nozzles may be used. Adjacent nozzles may be separated by one or more heaters and / or heat sinks, thereby repeating the process as described above. Figures 8 to 10 Some or all of the arrangements shown. In some embodiments, each nozzle may have an associated heater and / or radiator arranged around the nozzle on opposite sides; that is, multiple heaters and / or radiators may be present in the region between adjacent nozzles. In other embodiments, adjacent nozzles may “share” a heater or radiator, such that a set of heaters and / or radiators is present in the region between adjacent nozzles, thereby providing heating and / or deheating in the associated region of each nozzle adjacent to the heater and / or radiator. Individual nozzles may operate independently of each other, or multiple nozzles may operate collaboratively. For example, in the presence of multiple nozzles, each nozzle may operate continuously without heating or otherwise operating other nozzles, thereby allowing the sequential deposition of different materials. Alternatively, multiple nozzles may operate simultaneously to allow the simultaneous deposition of different materials or the same material at different locations.

[0100] Similarly, some embodiments may include, for example: Figures 8 to 10 The multiple printheads shown may each include one or more nozzles, heaters, and / or radiators, as previously disclosed. Like the previously disclosed nozzles, the multiple printheads may operate individually or collaboratively, sequentially or simultaneously. Adjacent printheads may be separated by an intermediate air gap, thereby forming... Figures 8 to 10 The printed head structure shown is an array of repeating patterns.

[0101] It is worth noting that the embodiments disclosed herein allow the OVJP deposition apparatus to operate in a manner that maintains the ambient temperature of the deposition chamber, and in some embodiments, the ambient area between the printhead and the substrate does not exceed 40°C when the printhead is in operation (typically at 200 to 450°C).

[0102] To operate the OVJP printhead as disclosed herein, the printhead can be heated to a temperature of approximately 200 to 450°C, at which point a carrier gas and entrained organic material can be ejected from one or more nozzles in the printhead for deposition on the substrate, as previously disclosed. By using the heat sink and air gap as previously disclosed, the local environment surrounding the printhead can be cooled sufficiently to prevent the ambient temperature within the deposition chamber (typically a vacuum chamber) from rising above approximately 40°C due to printhead operation.

[0103] It should be understood that the various embodiments described herein are merely illustrative and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted with other materials and structures without departing from the spirit of the invention. The invention as claimed may therefore include variations of the specific examples and preferred embodiments described herein, as will be apparent to those skilled in the art. It should be understood that various theories regarding why the invention works are not intended to be limiting.

Claims

1. An organic vapor jet printing (OVJP) apparatus, comprising: The OVJP printhead includes: The nozzle is configured to inject organic material entrained in the carrier gas; A first heater, disposed on a first side of the OVJP printhead; and A second heater is disposed on the second side of the OVJP printhead, wherein the OVJP printhead is disposed between the first and second heaters; A first radiator is configured to be adjacent to the first heater and separated from the first heater via a first air gap; A second radiator is configured to be adjacent to the second heater and separated from the second heater via a second air gap. The printhead is movable independently of the first and second heat sinks.

2. The OVJP device according to claim 1, further comprising a first bearing disposed adjacent to the first heat sink.

3. The OVJP device according to claim 2, wherein at least a portion of the first bearing is separated from the first heat sink via a third air gap.

4. The OVJP apparatus of claim 1, further comprising an insulating jacket disposed around one or more gas lines connecting the printhead to one or more sources of carrier gas and organic material, the insulating jacket comprising an internal thermally conductive jacket arranged and configured to heat the one or more gas lines.

5. The OVJP device according to claim 4, wherein the thermal insulation jacket comprises a vacuum jacket surrounding the inner thermally conductive jacket.

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