Height measurement and control in enclosed spaces for deposition systems

Abstract

To provide devices for fabricating organic emissive devices that may make measurements closer to a printing zone and may provide thermal management for the sensors.SOLUTION: A device includes: a print head 101; an optical sensor 302 for a micro-nozzle array of depositors of the print head 101; a reflective optical device 301 for reflecting a signal output by the optical sensor 302, and for reflecting a signal from a surface of a substrate 103 to the optical sensor 302; a processor 306 communicatively coupled to the optical sensor 302 to determine a distance between the optical sensor 302 and the surface of the substrate 103; and an actuator 104 coupled to the print head 101 to adjust a position of the print head 101 to the substrate 103.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 63 / 054,150, filed July 20, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to devices and techniques for fabricating organic light emitting devices, such as organic light emitting diodes, and devices and techniques including the same. The fabrication device can perform measurements closer to the printing area and can provide thermal management of the sensors. [Background technology]

[0003] Optoelectronic devices utilizing organic materials are becoming increasingly desirable for many reasons. Because many of the materials used to fabricate such devices are relatively inexpensive, organic optoelectronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as flexibility, may make them well suited 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 may have performance advantages over conventional materials. For example, the wavelength at which an organic light-emitting layer emits light can usually be easily tuned with appropriate dopants.

[0004] OLEDs utilize thin organic films that emit light when a voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting. Several OLED materials and configurations are described in U.S. Patent Nos. 5,623,999; 5,723,949; 5,723,979; 5,723,979; and 5,723,979, the disclosures of which are incorporated herein by reference in their entireties.

[0005] One application of phosphorescent molecules is full-color displays. Industry standards for such displays require pixels adapted to emit specific colors, referred to as "saturated" colors. In particular, these standards require saturated red, green, and blue pixels. Alternatively, OLEDs can be designed to emit white light. Conventional liquid crystal display emission from a white backlight is filtered with absorption filters to produce red, green, and blue emission. Similar techniques can be used with OLEDs. White OLEDs can be either single-layer EML devices or stacked structures. Color can be measured using CIE coordinates, which are well known in the art.

[0006] As used herein, the term "organic" includes polymeric and small molecule organic materials that can be used to fabricate organic optoelectronic devices. "Small molecule" refers to any organic material that is not a polymer, and "small molecules" can actually be quite large. Small molecules can contain repeating units in some circumstances. For example, using a long-chain alkyl group as a substituent does not remove a molecule from the "small molecule" class. Small molecules can be incorporated into polymers, for example, as pendant groups on a polymer backbone or as part of the backbone. Small molecules can also serve as the core moiety of dendrimers, which consist of a series of chemical shells built on the core moiety. The core moiety of a dendrimer can be a fluorescent or phosphorescent small molecule emitter. Dendrimers can be "small molecules," and all dendrimers currently used in the field of OLEDs are considered to be small molecules.

[0007] As used herein, "top" means furthest from the substrate, while "bottom" means closest to the substrate. When a first layer is described as "disposed over" a second layer, the first layer is disposed further from the substrate. There may be other layers between the first and second layers, unless it is specified that the first layer is "in contact with" the second layer. For example, a cathode may be described as "disposed over" an anode, even though there may be various organic layers in between.

[0008] As used herein, "solution processable" means capable of being dissolved, dispersed or transported in and / or deposited from a liquid medium, either in the form of a solution or suspension.

[0009] A ligand may be referred to as "photoactive" if it is considered to directly contribute to the photoactive properties of the emissive material. A ligand may be referred to as "ancillary" if it is considered not to contribute to the photoactive properties of the emissive material, although the ancillary ligand may modify the properties of the photoactive ligand.

[0010] As used herein, and as generally understood by those skilled in the art, a first "highest occupied molecular orbital" (HOMO) or "lowest unoccupied molecular orbital" (LUMO) energy level is "greater than" or "higher than" a second HOMO or LUMO energy level if the first energy level is closer to the vacuum energy level. Because ionization potentials (IPs) are measured as negative energies relative to the vacuum level, a higher HOMO energy level corresponds to an IP with a smaller absolute value (a less negative IP). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) with a smaller absolute value (a less negative EA). On a conventional energy level diagram with the vacuum level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A "higher" HOMO or LUMO energy level appears closer to the top of such a diagram than a "lower" HOMO or LUMO energy level.

[0011] As used herein, and as generally understood by those skilled in the art, a first work function is "greater than" or "higher than" a second work function if the first work function has a higher absolute value. Because work functions are generally measured as negative numbers relative to vacuum level, this means that a "higher" work function is more negative. On a conventional energy level diagram, with the vacuum level at the top, a "higher" work function is illustrated as being farther away from the vacuum level in the downward direction. Thus, the definitions of HOMO and LUMO energy levels follow a different convention than work functions.

[0012] Layers, materials, regions, and devices may be described herein in reference to the color of light they emit. Generally, a light-emitting region described herein as producing light of a particular color can include one or more light-emitting layers arranged in a stack on top of each other.

[0013] As used herein, a "red" layer, material, region, or device refers to one that emits light in the range of approximately 580-700 nm or has a maximum peak in its emission spectrum in that range. Similarly, a "green" layer, material, region, or device refers to one that emits light in the range of approximately 500-600 nm or has an emission spectrum with a peak wavelength in this range. A "blue" layer, material, region, or device refers to one that emits light in the range of approximately 400-500 nm or has an emission spectrum with a peak wavelength in this range. A "yellow" layer, material, region, or device refers to one that has an emission spectrum with a peak wavelength in the range of approximately 540-600 nm. In some arrangements, separate regions, layers, materials, regions, or devices may separately provide "deep blue" and "light blue" light. As used herein, in arrangements that separately provide "light blue" and "deep blue," the "deep blue" component refers to one that has a peak emission wavelength at least approximately 4 nm shorter than the peak emission wavelength of the "light blue" component. Typically, a "light blue" component has a peak emission wavelength in the range of approximately 465-500 nm, and a "deep blue" component has a peak emission wavelength in the range of approximately 400-470 nm, although these ranges can vary depending on the configuration. Similarly, a color conversion layer refers to a layer that converts or modifies light of another color into light having a wavelength specific to that color. For example, a "red" color filter refers to a filter that provides light having a wavelength in the range of approximately 580-700 nm. Generally, there are two classes of color conversion layers: color filters that modify the spectrum by filtering out undesired wavelengths of light, and color conversion layers that convert high-energy photons into lower-energy photons. A "color" component refers to a component that, when activated or used, generates or emits light having a specific color as described above. For example, a "first light-emitting region of a first color" and a "second light-emitting region of a second color different from the first color" describe two light-emitting regions that, when activated in a device, emit two different colors as described above.

[0014] As used herein, emissive materials, emissive layers, and emissive regions can be distinguished from one another and from other structures based on the light initially produced by the material, layer, or region, rather than the light ultimately emitted by the same or a different structure. The initial color generation is typically the result of an energy level change that leads to the emission of a photon. For example, an organic emissive material may initially produce blue light, which can be converted to red or green light by color filters, quantum dots, or other structures, such that the completed emissive stack or subpixel emits red or green light. In this case, the initial emissive material or layer may be referred to as the "blue" component, even if the subpixel is the "red" or "green" component.

[0015] In some cases, it may be preferable to describe the color of components such as light-emitting regions, subpixels, and color conversion layers based on the 1931 CIE coordinate system. For example, a yellow light-emitting material may have multiple peak emission wavelengths, one at or near the edge of the aforementioned "green" region and one in or near the edge of the "red" region. Thus, in this specification, each color term also corresponds to a shape in the 1931 CIE coordinate system color space. A shape in the 1931 CIE color space is formed by following the locus between two color points and any additional interior points. For example, the interior shape parameters for red, green, blue, and yellow can be defined as follows: [Table 1]

[0016] Further details regarding OLEDs and the above definitions can be found in US Pat. No. 6,223,999, which is incorporated herein by reference in its entirety. Summary of the Invention

[0017] According to embodiments, an organic light emitting diode / device (OLED) is also provided. The OLED can include an anode, a cathode, and an organic layer disposed between the anode and the cathode. According to embodiments, the organic light emitting device is incorporated into one or more devices selected from a consumer product, an electronic component module, and / or a lighting panel.

[0018] According to an embodiment, a device may include at least one print head having a micro-nozzle array of depositors for depositing material onto a substrate. The device may include at least one optical sensor for the micro-nozzle array of depositors of each print head to output a signal. A reflective optical device may be disposed in the at least one print head to reflect the signal output by the at least one optical sensor and reflect the signal from the surface of the substrate to the optical sensor. The device may include a processor communicatively connected to the at least one optical sensor to determine a distance between the at least one optical sensor and a target surface of the substrate based on an offset distance between the depositor and the substrate and a distance between the at least one optical sensor and the reflective optical device. One or more actuators may be connected to the at least one print head to move the at least one print head relative to an internal reference frame separated from an external chamber and adjust the position of the at least one print head relative to the substrate, and the processor may be communicatively connected to the one or more actuators to move the at least one print head. At least one of the devices can be fixedly connected to an internal reference frame by a mount, and the at least one print head can be configured to move in at least one axis of linear or rotational motion independent of the at least one optical sensor.

[0019] The reflective optical device can be a mirror, a prism, and / or a beam splitter. The reflective optical device may be milled, grinded, etched, deposited, or plated into a portion of the at least one print head.

[0020] The device may include a cooling device thermally connected to a mount of the at least one optical sensor for actively cooling the mount, and the mount may be an adjustable mount.

[0021] The processor may control the one or more actuators to move the at least one print head based on a first predetermined amount change in a first measured distance between the at least one sensor and the reflective optical device and / or a second predetermined amount change in a second measured distance between the reflective optical device and the substrate.

[0022] The at least one actuator of the device can include a first actuator and a second actuator. The at least one print head can have a first side and a second side, and the first actuator can be connected to the first side and the second actuator can be connected to the second side. The first actuator and the second actuator can control the position of the at least one print head such that a fly-height gap between the at least one print head and the substrate is controlled at the first side and the second side of the at least one print head having the micronozzle array of the depositor. The first actuator and the second actuator can provide the at least one print head with a linear degree of freedom along a substrate normal and a rotational degree of freedom in the plane of the substrate.

[0023] The at least one optical sensor of the device can include a first optical sensor and a second optical sensor, and the one or more actuators can include a first actuator and a second actuator. The first optical sensor can be disposed at a first end of the at least one printhead, and the second optical sensor can be disposed at a second end of the at least one printhead. The first optical sensor can determine a first displacement between the at least one printhead and the substrate, and the second optical sensor can determine a second displacement between the at least one printhead and the substrate. A first output of the first optical sensor can be used by the processor to control the first actuator, and a second output of the second optical sensor can be used by the processor to control the second actuator.

[0024] The at least one optical sensor may include a plurality of sensors for each of the one or more actuators, and the processor may control each actuator based on a plurality of signals received from the plurality of sensors.

[0025] The at least one printhead can include a plurality of first printheads and a plurality of second printheads arranged to form a printbar, the plurality of first printheads being offset from the plurality of second set of printheads to form staggered lines on the printbar.

[0026] The at least one print head can protrude through a temperature-controlled cooling plate, and the at least one optical sensor can be mounted on the temperature-controlled cooling plate.

[0027] The device may include at least one heater thermally connected to the at least one printhead for heating the at least one printhead. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 shows an organic light-emitting device.

[0029] [Figure 2] FIG. 2 shows an inverted organic light-emitting device that does not have a separate electron transport layer.

[0030] [Figure 3] FIG. 3 shows a front view and an isometric view of the device with the sensor mounted vertically aligned with the printing surface.

[0031] [Figure 4] FIG. 4 shows a front and isometric view of the device with a vertically mounted sensor measuring the leading or trailing surface of the substrate from the printhead.

[0032] [Figure 5] FIG. 5 shows a device with a horizontally mounted sensor and an array of optical deflection elements according to an embodiment of the disclosed subject matter.

[0033] [Figure 6] 6A-6C show the response of a device to changes in the measured height of a substrate surface, according to an embodiment of the disclosed subject matter.

[0034] [Figure 7] 7A and 7B show a comparison of reflected measurement paths for a horizontally mounted sensor with a 45 degree optical deflection element (FIG. 7A) and a 10 degree mounted sensor with a 40 degree optical deflection element (FIG. 7B), according to an embodiment of the disclosed subject matter.

[0035] [Figure 8] FIG. 8 shows the change in measured distance versus the actual change in fly height for different sensor mounting angles and optical deflection element pairs, according to an embodiment of the disclosed subject matter.

[0036] [Figure 9] FIG. 9 illustrates a printbar having multiple printheads including a measurement and control system according to an embodiment of the disclosed subject matter. DETAILED DESCRIPTION OF THE INVENTION

[0037] Generally, an OLED comprises at least one organic layer disposed between and electrically connected to an anode and a cathode. When a current is applied, the anode injects holes and the cathode injects electrons into the organic layer(s). The injected holes and electrons migrate to the oppositely charged electrode, respectively. When an electron and hole localize on the same molecule, an "exciton," a localized electron-hole pair with an excited energy state, is formed. Light is emitted via a photoemissive mechanism when the exciton relaxes. In some cases, the exciton may be localized on an excimer or exciplex. Non-radiative mechanisms, such as thermal relaxation, can also occur but are generally considered undesirable.

[0038] Early OLEDs used emissive molecules that emitted light from their singlet state ("fluorescence"), as disclosed, for example, in U.S. Patent No. 4,769,292, which is incorporated by reference in its entirety. Fluorescence emission typically occurs in a time frame of less than 10 nanoseconds.

[0039] More recently, OLEDs have been demonstrated that have emissive materials that emit light from triplet states ("phosphorescence"). Baldo et al., "Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices," Nature, Vol. 395, No. 151-154, 1998; ("Baldo-I") and Baldo et al., "Very high-efficiency green organic light emitting devices based on electrophosphorescence," Appl. Phys. Lett., Vol. 75, No. 3, 4-6 (1999) ("Baldo-II"), which are incorporated by reference in their entireties. Phosphorescence is described in further detail in U.S. Pat. No. 7,279,704, columns 5-6, which are incorporated by reference.

[0040] FIG. 1 shows an organic light-emitting device 100. The drawing is not necessarily 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 emissive 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 barrier layer 170. Cathode 160 is a compound cathode having a first conductive layer 162 and a second conductive layer 164. Device 100 may be fabricated by depositing the layers described, in order. The properties and functions of these various layers, as well as example materials, are described in further detail in U.S. Pat. No. 7,279,704, columns 6-10, which are incorporated by reference.

[0041] Further examples are available for each of these layers. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole-transporting layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated by reference in its entirety. Examples of emissive and host materials are disclosed in U.S. Patent No. 6,303,238 to Thompson et al., which is incorporated by reference in its entirety. An example of an n-doped electron-transporting layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated by reference in its entirety. U.S. Patent Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entireties, disclose examples of cathodes, including composite cathodes with a thin layer of metal, such as Mg:Ag, with an overlying transparent, conductive, sputter-deposited ITO layer. The theory and use of blocking 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 by reference in their entireties. Examples of injection layers are provided in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated by reference in its entirety. A description of protective layers can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated by reference in its entirety.

[0042] FIG. 2 shows an inverted OLED 200. The device includes a substrate 210, a cathode 215, an emissive layer 220, a hole-transport layer 225, and an anode 230. Device 200 can be fabricated by depositing the layers described, in order. Because the most common OLED configuration has the cathode disposed above the anode, and device 200 has cathode 215 disposed below anode 230, device 200 can be referred to as an "inverted" OLED. Materials similar to those described with respect to device 100 may be used in the corresponding layers of device 200. FIG. 2 provides an example of how some layers can be omitted from the structure of device 100.

[0043] The simple layer structures illustrated in Figures 1 and 2 are provided as non-limiting examples, and it is understood that embodiments of the present invention can be used in conjunction with a wide variety of other structures. The specific materials and structures described are exemplary in nature, and other materials and structures may be used. A functional OLED may be achieved by combining the various layers described in various ways, or layers may 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. While many of the examples provided herein describe the various layers as including a single material, it is understood that combinations of materials, such as a mixture of a host and a dopant, or more generally, a mixture, may be used. Layers may also 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 emissive layer 220 and may 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. The organic layer may include a single layer, or may further include multiple layers of different organic materials, such as those described with respect to Figures 1 and 2.

[0044] Structures and materials not specifically described may also be used, such as OLEDs (PLEDs) composed of polymeric materials, such as those disclosed in U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated by reference in its entirety. As a further example, an OLED having a single organic layer may be used. OLEDs may be stacked, for example, as described in U.S. Pat. No. 5,707,745 to Forrest et al., which is incorporated by reference in its entirety. OLED structures may deviate from the simple layered structures illustrated in FIGS. 1 and 2. For example, the substrate may include angled reflective surfaces to improve outcoupling, such as the mesa structure described in U.S. Pat. No. 6,091,195 to Forrest et al. and / or the recessed structure described in U.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated by reference in their entirety.

[0045] In some embodiments disclosed herein, light-emitting layers or materials, such as light-emitting layer 135 and light-emitting layer 220 shown in FIGS. 1 and 2 , respectively, can include quantum dots. Unless indicated explicitly or by context as understood by one of ordinary skill in the art, a "light-emitting layer" or "light-emitting material" as disclosed herein can include organic light-emitting and / or emissive materials that include quantum dots or equivalent structures. Such light-emitting layers can include only quantum dot material that converts light emitted by another light-emitting material or other light emitter, or can also include said another light-emitting material or other light emitter, or can emit light itself directly upon application of electric current. Similarly, color conversion layers, color filters, up-conversion layers or structures, or down-conversion layers or structures can include materials that include quantum dots, but such layers may not be considered "light-emitting layers" as disclosed herein. Generally, an "emissive layer" or material is one that emits initial light that does not emit initial light within the device, but can be converted by other layers, such as color filters or other color conversion layers, that can re-emit modified light of different spectral content based on the initial light emitted by the emissive layer.

[0046] Unless otherwise specified, any of the layers of the various embodiments can be deposited by any suitable method. For organic layers, preferred methods include deposition by thermal evaporation, such as those described in U.S. Pat. Nos. 6,013,982 and 6,087,196, which are incorporated by reference in their entireties; inkjet deposition; organic vapor phase deposition (OVPD), such as that described in U.S. Pat. No. 6,337,102 to Forrest et al., which is incorporated by reference in its entirety; and OVJP, such as that described in U.S. Pat. No. 7,431,968, which is incorporated 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 patterning through a mask, such as those described in U.S. Patent Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entireties, deposition via cold welding, and patterning associated with some deposition methods, such as inkjet and organic vapor jet printing (OVJP). Other methods may also be used. The material to be deposited may be modified to be compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, preferably containing at least three carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents with 20 or more carbons may be used, with 3 to 20 carbons being a preferred range. Materials with asymmetric structures may have better solution processability than those with symmetric structures, because asymmetric materials may be less prone to recrystallization. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.

[0047] Devices fabricated according to embodiments of the present invention may further include a barrier layer. One purpose of the barrier layer is to protect the electrodes and organic layers from damaging exposure to harmful species in the environment, including moisture, vapors, and / or gases. The barrier layer may be deposited over, under, or adjacent to the substrate, the electrode, or any other portion of the device, including the edges. The barrier layer may include a single layer or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may include 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 incorporate inorganic or organic compounds, or both. Preferred barrier layers include mixtures of polymeric and non-polymeric materials, as described in U.S. Pat. No. 7,968,146 and PCT Patent Application Nos. PCT / US2007 / 023098 and PCT / US2009 / 042829, which are incorporated herein by reference in their entireties. To be considered a "mixture," the polymeric and non-polymeric materials comprising the barrier layer should be deposited under the same reaction conditions and / or simultaneously. The weight ratio of polymeric to non-polymeric materials can be in the range of 95:5 to 5:95. The polymeric and non-polymeric materials can be made from the same precursor materials. In one example, the mixture of polymeric and non-polymeric materials consists essentially of polymeric silicon and inorganic silicon.

[0048] In some embodiments, at least one of the anode, cathode, or additional layers disposed on the organic light-emitting layer functions as an enhancement layer. The enhancement layer includes a plasmonic material that nonradiatively couples to the emitter material and exhibits a surface plasmon resonance that transfers excited-state energy from the emitter material to a nonradiative mode of surface plasmon polaritons. The enhancement layer is disposed within a threshold distance from the organic light-emitting layer, and the emitter material has a total nonradiative decay rate constant and a total radiative decay rate constant due to the presence of the enhancement layer, and at the threshold distance, the total nonradiative decay rate constant is equal to the total radiative decay rate constant. In some embodiments, the OLED further includes an outcoupling layer. In some embodiments, the outcoupling layer is disposed on the enhancement layer opposite the organic light-emitting layer. In some embodiments, the outcoupling layer is disposed on the opposite side of the enhancement layer from the light-emitting layer, but still outcouples energy from the surface plasmon mode of the enhancement layer. The outcoupling layer scatters energy from the surface plasmon polaritons. In some embodiments, this energy is scattered into free space as photons. In other embodiments, the energy is scattered from the surface plasmon mode into other modes of the device, such as, but not limited to, an organic waveguide mode, a substrate mode, or another waveguide mode. If the energy is scattered into a non-free-space mode of the OLED, other outcoupling schemes can be incorporated to extract the energy into free space. In some embodiments, one or more intervening layers can be disposed between the enhancement layer and the outcoupling layer. Examples of intervening layers can be dielectric materials, including organic, inorganic, perovskite, and oxide, and can include stacks and / or mixtures of these materials.

[0049] Enhancement layers alter the effective properties of the medium in which the emitter material resides, resulting in any or all of the following: a reduction in the emission rate; a change in the emission line shape; a change in the emission intensity with angle; a change in the stability of the emitter material; a change in the efficiency of the OLED; and a reduction in the efficiency roll-off of the OLED device. Placing an enhancement layer on the cathode side, the anode side, or both can result in an OLED device that utilizes any of the above-described effects. In addition to the specific functional layers shown in the various OLED examples described and illustrated herein, OLEDs according to the present disclosure can include any of the other functional layers frequently found in OLEDs.

[0050] The enhancement layer can be composed of a plasmonic material, an optically active metamaterial, or a hyperbolic metamaterial. As used herein, a plasmonic material is a material whose real part of its permittivity crosses zero in the visible or ultraviolet region of the electromagnetic spectrum. In some embodiments, the plasmonic material includes at least one metal. In such embodiments, the metal can include at least one 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. In general, a metamaterial is a medium composed of different materials such that the medium as a whole behaves differently from the sum of its parts. In particular, an optically active metamaterial is defined as a material that has both a negative permittivity and a negative magnetic permeability. On the other hand, a hyperbolic metamaterial is an anisotropic medium in which the permittivity or permeability has different signs in different spatial directions. Optically active metamaterials and hyperbolic metamaterials are distinct from many other photonic structures, such as distributed Bragg reflectors ("DBRs"), in that they are media that appear uniform in the direction of propagation on the length scale of the wavelength of light. Using terminology understood by those skilled in the art, the dielectric constant of a metamaterial in the direction of propagation can be described by an effective medium approximation. Plasmonic materials and metamaterials offer a way to control the propagation of light and can improve OLED performance in a variety of ways.

[0051] In some embodiments, the enhancement layer is provided as a planar layer. In other embodiments, the enhancement layer has periodically, quasi-periodically, or randomly arranged wavelength-sized features or periodically, quasi-periodically, or randomly arranged sub-wavelength-sized features. In some embodiments, the wavelength-sized features and sub-wavelength-sized features have sharp edges.

[0052] In some embodiments, the outcoupling layer has periodically, quasi-periodically, or randomly arranged wavelength-sized features or periodically, quasi-periodically, or randomly arranged subwavelength-sized features. In some embodiments, the outcoupling layer can be composed of nanoparticles, and in other embodiments, the outcoupling layer is composed of nanoparticles disposed on a material. In these embodiments, outcoupling can be tunable by at least one of varying the size of the nanoparticles, varying the shape of the nanoparticles, varying the material of the nanoparticles, adjusting the thickness of the material, varying the refractive index of the material or the refractive index of an additional layer disposed on the nanoparticles, varying the thickness of an enhancement layer, and / or varying the material of the enhancement layer. The nanoparticles of the device can be formed from at least one of a metal, a dielectric material, a semiconductor material, an alloy of a metal, a mixture of dielectric materials, a stack or layer of one or more materials, and / or a core of one type of material coated with a shell of another type of material. In some embodiments, the outcoupling layer is composed of at least metal nanoparticles, the metal being 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. The nanoparticles can have additional layers disposed thereon. In some embodiments, the polarization of the emitted light can be adjusted using the outcoupling layer. By varying the dimensions and periodicity of the outcoupling layer, the type of polarization that is preferentially outcoupled to air can be selected. In some embodiments, the outcoupling layer also functions as an electrode for the device.

[0053] It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin-statistic limit due to delayed fluorescence. In this specification, there are two types of delayed fluorescence: P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence occurs via triplet-triplet annihilation (TTA).

[0054] On the other hand, E-type delayed fluorescence does not depend on the collision of two triplets, but rather on the thermal population between the triplet and singlet states. Compounds capable of producing E-type delayed fluorescence must have a very small singlet-triplet gap. Thermal energy can activate the transition from the triplet state to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). A unique feature of TADF is that the delayed component increases with increasing temperature due to increasing thermal energy. If the reverse intersystem crossing rate is fast enough to minimize nonradiative decay from the triplet state, the fraction of the back-populated singlet excited state can reach 75%. The total singlet fraction can be 100%, which is far beyond the spin statistical limit.

[0055] The E-type delayed fluorescence characteristic can be observed in exciplex systems or single compounds. Without being bound by any theory, it is believed that to produce E-type delayed fluorescence, the emissive material must have a small singlet-triplet energy gap (ΔE-T). Metal-free organic donor-acceptor emissive materials can achieve this. The emission of these materials is often characterized as donor-acceptor charge transfer (CT) emission. The spatial separation of the HOMO and LUMO in these donor-acceptor compounds often results in a small ΔE-T. These states may involve CT states. Donor-acceptor emissive materials are often constructed by linking an electron-donating moiety, such as an amino or carbazole derivative, with an electron-accepting moiety, such as an N-containing six-membered aromatic ring.

[0056] Devices made according to embodiments of the present invention can be incorporated into a wide variety of electronic component modules (or units) that can be incorporated into various electronic products or intermediate components. Such electronic products or intermediate components include display screens, lighting devices (such as discrete light source devices or lighting panels), and the like, which can be utilized by end-user product manufacturers. Such electronic component modules can optionally include drive electronics and / or power sources. Devices made 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. Disclosed are consumer products comprising OLEDs that include compounds of the present disclosure in the organic layer of the OLED. Such consumer products include any type of product that includes one or more light sources and / or one or more visual displays of some kind. Some examples of such consumer products include flat panel displays, curved displays, computer monitors, medical monitors, televisions, billboards, lights for indoor or outdoor illumination and / or signaling, head-up displays, fully or partially transparent displays, flexible displays, rollable displays, foldable displays, stretchable displays, laser printers, telephones, mobile phones, tablets, phablets, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, camcorders, viewfinders, microdisplays (displays less than 2 inches diagonal), 3-D displays, virtual reality or augmented reality displays, vehicles, video walls including multiple displays aligned together, theater or stadium screens, and signage. A variety of control mechanisms, including passive matrix and active matrix, can be used to control devices made in accordance with the present invention. Many of the devices are intended for use within a temperature range comfortable to humans, such as 18°C ​​to 30°C, more preferably room temperature (20-25°C), but can also be used outside this temperature range, e.g., between -40°C and +80°C.

[0057] The materials and structures described herein may have applications in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may use the materials and structures. More generally, organic devices such as organic transistors may use the materials and structures.

[0058] In some embodiments, the OLED has one or more properties 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 comprising carbon nanotubes.

[0059] In some embodiments, the OLED further comprises a layer comprising a delayed fluorescent emitter. In some embodiments, the OLED comprises an RGB pixel array or a white and color filter pixel array. 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 having 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 having 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.

[0060] In some embodiments of the light-emitting region, the light-emitting region further comprises a host.

[0061] In some embodiments, the compound can be an emissive dopant. In some embodiments, the compound can 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.

[0062] The OLEDs disclosed herein can be incorporated into one or more of consumer products, electronic component modules, and lighting panels. The organic layer can be an emissive layer, and in some embodiments, the compound can be an emissive dopant, while in other embodiments, the compound can be a non-emissive dopant.

[0063] The organic layer can also include a host. In some embodiments, two or more hosts are preferred. In some embodiments, the host used can be a) ambipolar, b) electron-transporting, c) host-transporting, or d) a wide band gap material that contributes little to charge transport. In some embodiments, the host can include a metal complex. The host can be an inorganic compound.

[0064] Combination with other materials The materials described herein as useful for a particular layer in an organic light-emitting device can be used in combination with a wide variety of other materials present in the device. For example, the emissive dopants disclosed herein can be used in conjunction with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes, and other layers that may be present. The materials described or referenced below are non-limiting examples of materials that may be useful in combination with the compounds disclosed herein, and those skilled in the art can readily consult the literature to identify other materials that may be useful in combination.

[0065] A variety of materials can be used in the various emissive and non-emissive layers and arrangements disclosed herein. Examples of suitable materials are disclosed in U.S. Patent Application Publication No. 2017 / 0229663, which is incorporated by reference in its entirety.

[0066] Conductive dopants: The charge transport layer is doped with a conductive dopant to significantly change the density of charge carriers and thereby its conductivity. The conductivity can be increased by generating charge carriers in the matrix material or, depending on the type of dopant, a change in the Fermi level of the semiconductor can also be achieved. The hole transport layer can be doped with a p-type conductive dopant, and n-type conductive dopants are used in the electron transport layer.

[0067] HIL / HTL: The hole injection / transport material used in the present invention is not particularly limited, and any compound may be used as long as the compound is typically used as a hole injection / transport material.

[0068] EBL: An electron blocking layer (EBL) can be used to reduce the number of electrons and / or excitons that leave the emissive layer. The presence of such a blocking layer in a device can result in significantly higher efficiency and / or longer lifetime compared to a similar device lacking a blocking layer. Blocking layers can also be used to confine emission to a desired region of an OLED. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and / or a higher triplet energy than the emitter closest to the EBL interface. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and / or a higher triplet energy than one or more of the hosts closest to the EBL interface. In one aspect, the compound used in the EBL contains the same molecule or the same functional group used as one of the hosts described below.

[0069] host: The light-emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as a light-emitting material, and may contain a host material using the metal complex as a dopant material. The host material is not particularly limited, and any metal complex or organic compound can be used as long as the triplet energy of the host is higher than that of the dopant. Any host material can be used with any dopant as long as the triplet criterion is met.

[0070] HBL: A hole-blocking layer (HBL) can be used to reduce the number of holes and / or excitons that escape from the emissive layer. The presence of such a blocking layer in a device can result in significantly higher efficiency and / or longer lifetime compared to a similar device lacking a blocking layer. A blocking layer can also be used to confine emission to a desired region of an OLED. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and / or a higher triplet energy than the emitter closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and / or a higher triplet energy than one or more of the hosts closest to the HBL interface.

[0071] ETL: The electron transport layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped) or doped. Doping may be used to enhance conductivity. Examples of ETL materials are not particularly limited, and any metal complex or organic compound typically used to transport electrons may be used.

[0072] Charge generation layer (CGL) In tandem or stacked OLEDs, the CGL plays a key role in performance and consists of an n-doped layer and a p-doped layer for electron and hole injection, respectively. Electrons and holes are supplied from the CGL and the electrodes. Consumed electrons and holes in the CGL are replenished by electrons and holes injected from the cathode and anode, respectively, until the bipolar current gradually reaches a steady state. Typical CGL materials contain n-type and p-type conductivity dopants used in the transport layers.

[0073] Vapor jet deposition methods for manufacturing OLEDs can include material dispensing systems that use micronozzle arrays arranged on a print bar. The gap between the nozzle and substrate can be adjusted to achieve a desired thickness, width, and / or uniformity of the thin film of deposited material produced as the substrate and nozzle move relative to each other in the print press. A displacement sensor can provide feedback to a controller and / or processor, which can adjust the height of the print bar to maintain the desired gap between the nozzle and the substrate. The offset between the sensor mounting position and the nozzle can be a predetermined distance. The distance between this predetermined distance and the measured distance between the nozzle and the substrate is the gap. Because the substrate surface may not be flat at some scale relative to the desired print gap, the gap can also be measured near the print area.

[0074] Organic vapor jet printing (OVJP) is a hot printing process in which the surface of a substrate can move while being subjected to thermal loads from a hot vapor jet and the vicinity of a hot print bar, which can have a predetermined temperature range. Embodiments of the disclosed subject matter can maintain the gap between the micronozzle array and the substrate to a tighter tolerance (e.g., a predetermined tolerance range) when a sensor can measure the gap near the printing area. Because the operating temperature range of the sensor is lower than the operating temperature range of the print bar, embodiments of the disclosed subject matter can thermally manage the sensor. Embodiments of the disclosed subject matter can take measurements closer to the printing area and provide thermal management of the sensor.

[0075] Embodiments of the disclosed subject matter monitor the distance between the substrate and a micronozzle-based depositor in a printhead of an OVJP system. In some embodiments, various types of sensors, such as optical and capacitive sensors, can be used to determine the distance between the nozzle and the surface. In one embodiment, an array of optical displacement sensors (e.g., multiple sensors) can be used with each micronozzle array. An optical signal can be reflected normal to the target surface of the substrate and returned to the sensor. A processor can calculate the distance from the sensor to the substrate surface. The processor can use this value, along with a predetermined offset between the nozzle mounting height and the sensor, to determine the nozzle-to-substrate gap. This gap is sometimes referred to as the fly height.

[0076] 3 shows a front view and an isometric view of a device with a vertically mounted sensor aligned with the printing surface, along with a mounting arrangement according to an embodiment of the disclosed subject matter. The print head 101 can include a microlens array of a depositor 102 positioned above a substrate 103. The position of the print head 101 can be controlled by a plurality of actuators 104 (e.g., multiple actuators) to adjust the height of each side of the print head 101. An optical sensor 105 can be rigidly coupled to a first side and a second side of the print head 101 by standoffs 106. The distance 107 between the substrate 103 and the depositor 102 is calculated from the difference between a measured distance 108 from the sensor 105 to the substrate and an offset distance 109 between each sensor 105 and the depositor 102. As shown in FIG. 3, the sensor 105 can be mounted flush with the depositor array 102, or as shown in FIG. 4, the sensor 105 can be on the front and / or rear side of the depositor array 102.

[0077] 3 and 4 show diagrams of the print head 101 in a vertical orientation, with the substrate 103 translating normal to the page in FIG. 3 and translating horizontally in FIG. 4. The sensor 105 shown in FIGS. 3 and 4 can have a body with a diameter of 2 mm, which may be the smallest diameter that can be used in the embodiment shown in FIGS. 3 and 4. The operating temperature of the print head 101 may be several hundred degrees Celsius higher than the maximum operating temperature of the sensor 105. A standoff 106 (e.g., a rigid fixture) connecting the sensor 105 to the print head 101 can prevent the sensor 105 from overheating. In practice, the standoff 106 can separate the sensor 105 from the printing area by more than 5 mm, thermally insulating the sensor 105. Measuring 5 mm away from the printing area may introduce errors.

[0078] FIG. 5 illustrates a device with a horizontally mounted sensor and mirror arrangement according to an embodiment of the disclosed subject matter. In this embodiment, the device can include a reflective optical device 301, such as a mirror, prism, and / or beam splitter, and a horizontally mounted sensor 302. The body of the sensor 302 does not need to be connected to the print head 101 by a standoff (e.g., the standoff 106 shown in FIGS. 3 and 4 ) when a reflective optical device 301 is used. Alternatively, the sensor 302 can be fixed in position relative to an internal reference frame 303, and the print head 101 moves vertically via movement of an actuator connecting the print head 101 to the fixed frame 303. Fixing the position of the optical sensor 302 probe can provide cooling and / or thermal management for the sensor 302, improving the accuracy and repeatability of displacement measurements and reducing the chance of damage to the sensor 302. 5, the measurement made by sensor 302 can be an integrated distance of both distance 304 between sensor 302 and mirror reflective optical device 301 and distance 305 between reflective optical device 301 and substrate 103. The offset distance between the nozzle height and the distance measured by sensor 304 can be used by processor 306 to perform fly height calculations. Processor 306 can be communicatively connected to actuator 104 and sensor 302. The processor can control actuator 104 based on the output signal from sensor 302.

[0079] 6A-6C show the device's response to changes in substrate surface position in arbitrary units. FIG. 6A shows the initial configuration of the device where the sensor measures 27 units, and the actual fly height 401 is 4 units. The path 402 from the sensor to the mirror is 11 units, and the path 403 from the mirror to the substrate is 16 units. The sum of the paths can be the distance output by the sensor. The offset between the sensor and the nozzle can be the difference between these distances (i.e., 27-4=23 units). This offset can be used by the processor to report the accurate fly height.

[0080] If the device observes a change of −2 in the measurement, the processor and / or sensor can control the actuator 404 to adjust the print head position upward by 2 units, as shown in FIG. 6B. FIG. 6C shows the print head after adjustment to the predetermined position. The measurement can be at an initial point of 27 units, and the distance between the depositor array and the substrate can be at an initial value of 4 units. The sensor position can be fixed so that the point where the sensor beam intersects with the reflective optical device 405 can change as the print head moves. The measurement distance can change as a function of changes in both the path length between the sensor and the reflective optical device and the path length between the reflective optical device and the substrate. The path length between the substrate and the reflective optical device may not change in FIGS. 6B and 6C. The path length between the sensor and the reflective optical device can increase by 2 units as the print head is raised. The distance between the depositor array and the substrate can be maintained constant as long as the total path length remains constant. The opposite may occur if the print head is lowered rather than raised. The path length between the reflective optical device and the substrate may initially increase, and in response, the print head may move downward. This downward movement may not change the optical path length between the print head and the substrate, but may decrease the path length between the reflective optical device and the sensor until it returns to the target value. The response time of these changes may be measured in milliseconds for the given acquisition rate of the sensor.

[0081] 7A and 7B show a comparison of reflected measurement paths for a horizontally mounted sensor with a 45 degree reflective optical device (FIG. 7A) and a 10 degree mounted sensor with a 40 degree reflective optical device (FIG. 7B), according to an embodiment of the disclosed subject matter.

[0082] Regarding the selection of the mounting location, difficulties arise when mounting the sensor horizontally, as shown in FIG. 7A. To ensure that the measurement point is as close as possible to the printing area, the reflective optical device 501 can be positioned near the depositor array, i.e., near the substrate 502. The centerline 503 of the sensor can be mounted horizontally at a height 504 greater than its radius to avoid contact with the substrate 502, allowing the reflective optical device 501 to be positioned closer to the substrate. FIG. 7B shows that by using a 10-degree mounting angle 505 paired with a 40-degree reflective optical device 501, the measurement point can be positioned closer to the printing area. This configuration allows the body of the sensor to remain away from the hot printhead assembly and substrate 502.

[0083] 7B shows that when the sensor is at any angle between horizontal and vertical, the processor can scale the sensor's measurement signal from a calibrated "zero" position. In FIG. 7B, the units are normalized to show that a change of 1 arbitrary unit (AU) causes the measured path length 507 to increase by 1 AAU before reaching the reflective optical device, which may have a vertical movement 508 that is 0.174 AAU less. Thus, the sensor may have a height change of 1 - 0.174 = 0.826 AAU.

[0084] FIG. 8 illustrates the change in measured distance versus the actual change in fly height for various sensor mounting angles and respective optical device pairs, according to embodiments of the disclosed subject matter. The vertical axis 601 illustrates the measured change in optical path length, and the horizontal axis 602 illustrates the actual change in fly height. Lines are shown for sensors mounted at the substrate surface with a 45-degree reflective optical device (e.g., line 603), a 40-degree reflective optical device and 10 degrees above the substrate surface (e.g., line 604), a 40-degree reflective optical device and 20 degrees above the substrate surface (e.g., line 605), and a 30-degree reflective optical device and 30 degrees above the substrate surface (e.g., line 606). Scaling of tilted sensors can reduce the measured displacement change relative to the actual displacement change. While the device processor can account for changes in scaling, this can further reduce the accuracy of displacement measurements obtained from the sensor. In embodiments of the disclosed subject matter, sensors can be mounted as horizontally or vertically as possible to minimize these effects.

[0085] FIG. 9 illustrates a printbar including multiple printheads according to an embodiment of the disclosed subject matter. The printbar assembly in FIG. 9 is viewed from below the substrate. Multiple printheads 701 can be arranged in a row (e.g., two rows as shown in FIG. 9) to form staggered lines in a direction 702 perpendicular to the line of printheads 701, eliminating gaps in coverage on a substrate moving beneath the printheads 701. Each printhead 701 can have a reflective optical device 703 at each end of its outer surface. An optical sensor 704 can be aligned with each reflective optical device 703 to track the displacement between the depositor at the bottom of the printhead 701 and the substrate at that position. This information can be provided to a processor, and actuators can be used to adjust the printbar to maintain a constant fly height between each printhead 701 in the printbar and the substrate.

[0086] Embodiments of the disclosed subject matter improve measurement reliability by moving the measurement point closer to the substrate, an area that was previously inaccessible. The sensor can be mounted away from the hot assembly that includes the printhead, which significantly reduces the thermal load on the sensor and its mount. Embodiments of the disclosed subject matter improve sensor life and maintain robust and reliable measurements. Devices with features of embodiments of the disclosed subject matter can scale up because sensors are not mounted along the same nozzle face, as shown in FIG. 3 . Instead, they can be mounted above the substrate surface on either the front or back side.

[0087] 5-9 can include at least one printhead (e.g., printhead 101 shown in FIG. 5) including a depositor micronozzle array (depositor 102 shown in FIG. 5) for depositing material onto a substrate (substrate 103 shown in FIG. 5; substrate 502 shown in FIGS. 7A and 7B). Some embodiments of the disclosed subject matter can include at least one thermally coupled heater for heating the at least one printhead. The device can have at least one optical sensor (e.g., sensor 302 shown in FIG. 5; sensor 704 shown in FIG. 9) for each printhead depositor micronozzle array to output a signal.

[0088] A reflective optical device (e.g., reflective optical device 301 shown in FIG. 5 ; reflective optical device 501 shown in FIGS. 7A and 7B ; reflective optical device 703 shown in FIG. 9 ) can be disposed on at least one print head to reflect signals output by at least one optical sensor and reflect the signals from the surface of the substrate to the sensor. The reflective optical device can be a mirror, a prism, or a beam splitter. The reflective optical device may be milled, grinded, etched, deposited, or plated into a portion of at least one print head.

[0089] A processor (e.g., processor 306 shown in Figure 5) can be communicatively connected to the at least one optical sensor to determine a distance between the at least one optical sensor and a target surface of the substrate based on an offset distance between the depositor and the substrate and a distance between the at least one optical sensor and the reflective optical device. The processor can be communicatively connected to the actuator to control the actuator based on signals received from the optical sensor.

[0090] One or more actuators (e.g., actuator 104 shown in FIG. 5) can be connected to the at least one print head to move the at least one print head relative to an internal reference frame (e.g., internal reference frame 303 in FIG. 5) separated from the external chamber. The internal reference frame can be configured to be rigid. The external chamber can contain and / or surround the print head, sensor, reflective optical device, actuator, substrate, and internal reference frame. The at least one sensor can be fixedly connected to the internal reference frame with a mount. The at least one print head can be configured to move in at least one axis of linear or rotational motion independently of the at least one optical sensor. For example, an actuator can move the at least one print head independently of the optical sensor.

[0091] The processor can be configured to control one or more actuators to move the at least one print head based on a first predetermined amount change in a first measured distance between the at least one sensor and the reflective optical device and / or a second predetermined amount change in a second measured distance between the reflective optical device and the substrate.

[0092] The at least one actuator can include a first actuator and a second actuator. The at least one print head can have a first side and a second side, and the first actuator can be connected to the first side and the second actuator can be connected to the second side. The first actuator and the second actuator can control the position of the at least one print head such that a fly-height gap between the at least one print head and the substrate is controlled on the first side and the second side of the at least one print head having the micronozzle array of the depositor. The first actuator and the second actuator can provide the at least one print head with a linear degree of freedom along a normal to the substrate and a rotational degree of freedom in the plane of the substrate.

[0093] In some embodiments, the cooling device can be thermally connected to the sensor mount. The cooling device can actively cool the mount of the at least one optical sensor. The sensor mount can be an adjustable mount and can be configured to change the orientation of the sensor.

[0094] In some embodiments, the at least one optical sensor can include a first optical sensor and a second optical sensor, and the one or more actuators can include a first actuator and a second actuator. The first optical sensor can be disposed at a first end of the at least one print head, and the second optical sensor can be disposed at a second end of the at least one print head. The first optical sensor can determine a first displacement between the at least one print head and the substrate, and the second optical sensor can determine a second displacement between the at least one print head and the substrate.

[0095] A first output from the first optical sensor can be used by the processor to control a first actuator, and a second output from the second optical sensor can be used by the processor to control a second actuator.

[0096] In some embodiments, the at least one optical sensor may include multiple sensors for each of the one or more actuators, and the processor may control each actuator based on multiple signals received from the multiple sensors.

[0097] The at least one printhead can include a plurality of first printheads and a plurality of second printheads arranged to form a printbar, and the plurality of first printheads can be offset from the plurality of second set of printheads to form staggered lines on the printbar.

[0098] In some embodiments, the at least one print head can protrude through a temperature-controlled cooling plate, and the at least one optical sensor can be mounted on the temperature-controlled cooling plate.

[0099] It is understood that the various embodiments described herein are by way of example only and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein can be substituted with other materials and structures without departing from the spirit of the invention. Thus, the present invention as claimed may include variations from the specific examples and preferred embodiments described herein, as will be apparent to those skilled in the art. It is understood that various theories as to why the invention works are not intended to be limiting. [Prior art documents] [Patent documents]

[0100] [Patent Document 1] U.S. Patent No. 5,844,363 [Patent Document 2] U.S. Patent No. 6,303,238 [Patent Document 3] U.S. Patent No. 5,707,745 [Patent Document 4] U.S. Patent No. 7,279,704

Claims

1. An organic light emitting device manufacturing device having a print head for organic vapor jet printing (OVJP) deposition, comprising: at least one printhead including a micro-nozzle array of depositors for depositing material onto a substrate; at least one optical sensor for the micro-nozzle array of the depositor of each print head for outputting a signal; a reflective optical device disposed on the at least one printhead for reflecting the signal output by the at least one optical sensor and for reflecting the signal from the surface of the substrate to the optical sensor; a processor communicatively connected to the at least one optical sensor for determining a distance between the at least one optical sensor and a target surface of the substrate based on a distance between the depositor and the substrate and a distance between the at least one optical sensor and the reflective optical device; one or more actuators connected to the at least one print head for moving the at least one print head relative to an internal reference frame separated from an external chamber to adjust the position of the at least one print head relative to the substrate; the processor is communicatively coupled to the one or more actuators to move the at least one print head; the at least one optical sensor is fixedly connected to the internal reference frame by a mount, and the at least one print head is configured to move in at least one axis of linear or rotational motion independent of the at least one optical sensor.

2. 10. The device of claim 1, further comprising a cooling device thermally connected to the mount of the at least one optical sensor for actively cooling the mount.

3. 2. The device of claim 1, wherein the processor controls the one or more actuators to move the at least one print head based on at least one selected from the group consisting of a first predetermined amount change in a first measured distance between the at least one optical sensor and the reflective optical device, and a second predetermined amount change in a second measured distance between the reflective optical device and the substrate.

4. At least one of the actuators includes a first actuator and a second actuator; the at least one printhead having a first side and a second side, the first actuator connected to the first side and the second actuator connected to the second side; 2. The device of claim 1, wherein the first and second actuators control the position of the at least one print head such that a fly-height gap between the at least one print head and the substrate is controlled on the first and second sides of the at least one print head having the micronozzle array of the depositor, and the first and second actuators provide the at least one print head with a linear degree of freedom along a normal to the substrate and a rotational degree of freedom in the plane of the substrate.

5. the at least one optical sensor includes a first optical sensor and a second optical sensor, the one or more actuators include a first actuator and a second actuator; the first optical sensor is located at a first end of the at least one print head and the second optical sensor is located at a second end of the at least one print head; the first optical sensor determines a first displacement between the at least one print head and the substrate, and the second optical sensor determines a second displacement between the at least one print head and the substrate; 2. The device of claim 1, wherein a first output of the first optical sensor is used by the processor to control the first actuator, and a second output by the second optical sensor is used by the processor to control the second actuator.

6. 2. The device of claim 1, wherein the at least one optical sensor includes a plurality of sensors for each of the one or more actuators, and the processor controls each actuator based on a plurality of signals received from the plurality of sensors.

7. 10. The device of claim 1, wherein the at least one printhead comprises a plurality of first printheads and a plurality of second printheads arranged to form a printbar.

8. 8. The device of claim 7, wherein the first set of printheads are offset from the second set of printheads to form staggered lines on the printbar.

9. The device of claim 1 , wherein the at least one printhead protrudes through a temperature-controlled cooling plate.

10. The device of claim 9 , wherein the at least one optical sensor is mounted on a temperature-controlled cooling plate.

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