Split OLED

Abstract

An OLED device comprising: an array of bottom-emitting OLED segments separated by non-emissive gaps disposed on a common transparent substrate, each OLED segment defined by a transparent bottom electrode segment and a top electrode and a light-emitting organic layer between the top and bottom electrode segments, each split bottom electrode electrically connected to an individual power feed, at least a portion of the power feed being disposed in the emitted light path between the bottom electrode segment and the transparent substrate, and at least one refractive index-reducing material disposed between the split bottom electrode and the transparent substrate, the refractive index-reducing material being disposed between a lower surface of the power feed and an upper surface of the transparent substrate, and / or between a lower surface of the bottom electrode segment and an upper surface of the power feed, and / or between lateral spaces separating the individual power feeds.

Description

[Technical field]

[0001] This application relates to segmented OLEDs.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 192,942, filed May 25, 2021, Attorney Docket No. OLWK-0024-USP. [Background technology]

[0003] LED and OLED lighting panels offer many advantages for general lighting applications. LED and OLED lighting panels are efficient in terms of light output versus power consumption. LED and OLED lighting panels are low voltage, which helps avoid potential electric shock, are less likely to spark in potentially explosive environments, and reduce strain on auxiliary electrical systems. With proper internal design, the spectrum of light emitted can be altered. LED and OLED lighting panels produce little to no ultraviolet or infrared radiation. LED and OLED lighting panels are instant on, meaning they always emit light instantly when power is applied.

[0004] LED light sources are essentially small point light sources, and many LED devices must be combined to be used as a flat general lighting source. This increases manufacturing costs and complexity. The uniformity of the light surface must be controlled through proper design. LEDs generate heat, so heat countermeasures such as heat sinks are necessary. With proper system design, practical LED lighting panels can be made very thin, from 3 to 16 mm.

[0005] OLED light sources are essentially flat area light sources. OLED light sources offer several advantages over LED lighting panels. For example, they can be thinned to less than 1 mm and generate very little heat under normal operating conditions. However, OLED lifetime can be an issue. Both LED and OLED lighting panels can be fabricated on flexible or curved substrates, but OLEDs are considered preferable for these applications.

[0006] In summary, both LEDs and OLEDs are useful devices for lighting panels: they are efficient, low voltage, cool to the touch, and thin.

[0007] In some applications, multiple, independently controlled, individual OLED or LED devices can be mounted on a single substrate to provide a "tiled" device. In this application, each individual OLED or LED source is prefabricated independently, including its own substrate (except for electrical connections), and mounted side-by-side or in an array. Such devices can provide either variable general illumination (i.e., by powering individual units according to the desired amount of overall light) or low-resolution communication devices (i.e., by powering individual units in a pattern). OLED panels are often advantageous for such applications because they can have a larger light-emitting area than individual LEDs. This allows for a larger fill factor (total light-emitting area), which is often desirable. To achieve a larger light-emitting area with an LED source, multiple LEDs sharing the same power source within the same area must be used. This increases manufacturing complexity and cost, and does not provide a uniform appearance without the use of a diffuser (which reduces the efficiency of the light output and reduces the sharpness and contrast at the edges of the light-emitting area).

[0008] In other applications, multiple independently controlled individual OLED devices may be fabricated directly on a single common substrate to provide a "split" OLED device. In this application, split OLEDs are fabricated with each independent OLED segment fabricated directly on the same substrate, either completely side-by-side or in an array. There are non-emitting gaps or spaces between the individual segments. Such split OLED light sources offer manufacturing and cost advantages, since many layers can be shared among all units, eliminating the need to handle and package separate OLED panels. Because the LEDs must be fabricated individually on their own substrates, it is not possible to fabricate a true split LED device where all the LEDs share a common internal substrate. Split OLED devices can provide either variable general lighting or low-resolution communication devices.

[0009] Split OLED devices are particularly suited for automotive exterior lighting applications (e.g., tail lights) because, unlike LED devices, they do not require reflectors, light guides, or additional optical components to produce a homogenous surface light. For example, see Non-Patent Document 1. Furthermore, applications such as automotive tail lights often require some degree of visibility from the side as well as direct visibility from the rear, so tail light assemblies often have complex designs with a mix of curved and relatively flat surfaces. Split OLED devices can be fabricated on flexible substrates, simplifying design considerations for non-planar tail light assemblies. However, automotive tail lights are a key component of the vehicle's exterior appearance and must provide a sophisticated design and appearance.

[0010] Generally, OLED devices are formed on a substrate and can be either top-emitting (light emission from the surface opposite the substrate) or bottom-emitting (light emission through a transparent substrate). To create individually controlled OLED segments, at least one electrode must be divided into segments, i.e., the electrode of one OLED segment is electrically isolated from the corresponding electrode of a different OLED segment. In this way, the light emission from each OLED segment can be individually controlled by a single unique power feed to the electrode segment.

[0011] While both top- and bottom-emitting OLEDs are suitable for automotive applications, bottom-emitting OLEDs are preferred for at least two reasons. First, exterior applications require a robust encapsulant, which is difficult to achieve with transparent encapsulants, especially the flexible OLEDs required for top-emitting OLEDs. Bottom-emitting OLEDs allow for the use of a very robust encapsulant, since the encapsulant on the non-emitting side does not need to be transparent. Second, OLEDs are installed in limited spaces, so heat build-up can be an issue. Bottom-emitting OLEDs allow for a heat sink on the backside. With top-emitting OLEDs, the heat sink is located on the opposite side of the substrate, reducing the thermal transfer rate and resulting in poor cooling.

[0012] Power Feed It is preferable to form the OLED directly on the substrate before applying the organic OLED layers. This is because each segment has at least one Power Feed This is because they need to be patterned individually. Power FeedOne cost-effective way to fabricate power lines is to use photolithography processes and techniques that can create very fine patterns of conductive structures. However, photolithography is generally not compatible for use on top of the organic OLED layer. Fine metal masking processes and techniques can be used to create power lines on top of the organic OLED layer, but this is more costly and prone to defects during manufacturing. Additionally, the conductive structures created by the masking process are significantly larger than those that can be created by photolithography.

[0013] The need to have separate electrical power feeds (also called bus lines, metal traces, conductive traces, leads, current traces) for each segment of a split OLED device creates many design problems. In particular, placing the power feeds directly on the transparent substrate underneath the transparent bottom electrode of a bottom-emitting OLED can be problematic. If the power feeds are located underneath the active area of ​​an OLED segment, they may become visible due to light absorption or light scattering, which is undesirable. Furthermore, depending on their reflectivity, the power feeds may be visible even when the segment is off and not emitting light, as light incident on the OLED reflects off the power feeds. Having the power lines visible at all times detracts from the smooth, uniform appearance of a split OLED device.

[0014] This problem is Power Feed This is shown in Figure 1, which is a top-view photograph of a prior art bottom-emitting split OLED device in which the individual OLED segments are located beneath the electrode segments and in the emitting light path. In this particular example, the individual OLED segments are arranged in a triangular and hexagonal array with non-emitting gaps between them. The individual underlying power feeds are made of ITO and are located beneath the OLED segments and through the emitting light path. The power feeds are laterally separated from each other and from the overlying electrode segments by an insulating layer of SiO2. In this arrangement, the power feeds are clearly visible and the overall split OLED device does not have a smooth, neat appearance.

[0015] Power feeds are generally made of conductive materials such as metal oxides, metals, conductive polymers, carbon nanotubes, etc. They must be sufficiently conductive to deliver power over distances that may in some cases be relatively long (e.g., room segments) without significant IR (current x resistance or voltage) drop due to resistance. As a result, uneven brightness may occur. In general, the amount of IR drop is inversely proportional to the conductance, which for any particular material is controlled by its thickness (height), width and length. In many cases, even if the material is nearly transparent, the thickness and width required to provide sufficient conductance can affect the Power Feed If it is so thin that it is nearly invisible, the power loss due to IR drop may be unacceptably large. For this reason, it may be desirable for the power feed to be located in the non-emissive gaps between the individual OLED segments so that the power leads are not visible. Typically, the non-emissive gaps between the individual OLED segments are constant in width to provide a uniform appearance, and are made as thin as possible to maximize the emissive area.

[0016] However, in the non-emitting gaps between the OLED segments Power Feed It is problematic to place all Power Feed The OLED segments (one for each OLED segment) must be separate and electrically isolated from each other to allow independent control of each segment and to prevent short circuits. Depending on the OLED segment arrangement and gap width, the required Power Feed It may not be feasible to place all of the leads in the confined area of ​​the non-emitting gap without one lead touching or crossing over another, which would significantly increase manufacturing costs. Second, there is a need for a large number of OLED segments along or near the edge of the device. Power Feed Although the time is relatively short, the time for those OLED segments inside the device Power Feed In particular, Power FeedIt is relatively long if the path is complicated by being limited by the gap between the segments. If a common power source is assumed, it is long. Power Feed The power delivered by the short due to its increased resistance (IR drop) Power Feed This can result in non-uniform emission, with the interior segments emitting less light than the segments along the edges of the device. Power Feed must be larger in size (to reduce resistance) and multiple large Power Feed For these reasons, the gap between the OLED segments may not be wide enough to accommodate all of the Power Feed It is often impractical to place

[0017] To avoid such problems, most previous approaches to split OLED devices are based on top-emitting OLED formulations where the underlying power feed is not visible. However, split bottom-emitting OLED devices use a thin, transparent, thin-film OLED layer directly underneath each individual OLED segment. Power Feed There remains a need to place the power feed on the board so that it is not visible.

[0018] Non-Patent Document 2 describes a top-emitting OLED in which the bottom electrode of each segment is electrically connected by vias to metal traces disposed on the substrate, through a polymeric insulating layer that separates the two.

[0019] US Pat. Nos. 5,399,633 and 5,433,363 disclose a top-emitting OLED having a split bottom electrode separated from an underlying uniform conductive layer by an insulating layer that connects to individual segments through vias in the insulating layer.

[0020] US Pat. No. 5,399,433 discloses a bottom-emitting OLED in which conductive tracks for a split bottom electrode are placed on top of a top reflective electrode and connected through vias in an insulating layer.

[0021] US Pat. No. 5,399,633 discloses a top-emitting OLED having a current supply layer electrically connected to a bottom electrode by an electrical feedthrough in an electrical insulating layer between the current supply layer and the bottom electrode.

[0022] US Pat. No. 5,399,633 describes a top-emitting split OLED with a substrate, an electrical bus, an insulating layer, and a common electrode in contact with the electrical bus through a via in the insulating layer.

[0023] US Patent No. 5,399,633 describes a split OLED device in which the bottom electrode is divided into outer and inner segments. On top of the bottom electrode is a patterned current distribution structure covered by an insulating structure.

[0024] US Pat. No. 5,399,433 and US Pat. No. 5,499,466 describe split OLEDs with conductive tracks that run through the device and contact the hole injection tracks. The conductive metal tracks are visible in the light-emitting area and are connected with bus bars arranged around the periphery. US Pat. No. 5,499,433 also describes the use of conductive tracks that vary in thickness (height) or width from the outer segment to the inner segment to address the IR drop issue. A similar concept of conductive layers with thickness variations to address IR drop is disclosed in US Pat. No. 5,499,466.

[0025] US Patent No. 5,399,633 describes a split (passive matrix) OLED comprising an electrode bus on a substrate, an insulating layer on the electrode bus, and split electrodes on the insulating layer, the split electrodes being arranged so as to contact one of the electrical buses outside the area covered by the insulating layer.

[0026] US Pat. No. 5,399,433 describes a segmented OLED with conductive tracks disposed between the segments.

[0027] US Pat. No. 5,399,633 describes an OLED with two electrodes and conductive tracks, all of which are transparent.

[0028] US Pat. No. 5,399,633 describes a tiled OLED array (passive matrix) in which the electrodes of the OLED are connected along their edges to an external power source.

[0029] Patent Document 14 discloses an OLED with integrated touch sensor function, in which two electrodes for the touch sensor run in different directions. One of the touch electrodes is divided into sub-electrode lines covered with an insulating layer. These sub-electrodes are connected to metal bridge lines by vias.

[0030] US Pat. No. 5,399,433 describes an OLED in which bus bars (located outside the light-emitting area) that vary in size depending on the power supplied to the pixel are connected to the electrodes through vias in an insulating layer.

[0031] US Pat. No. 5,399,633 describes a split OLED display in which a first electrode segment, an insulating layer, a second electrode segment, a light-emitting organic layer, and a second electrode are disposed on a transparent substrate.

[0032] US Pat. No. 5,399,633 discloses an OLED having a patterned first conductive layer on one side of an insulating substrate and a common second conductive layer on the opposite side of the insulating substrate, which are connected by vias.

[0033] US Patent No. 5,999,336 discloses a formulation for a touch screen having an index matching layer above or below the pattern of an ITO electrode to reduce the visibility of the ITO. A SiO2 layer may be present on the index matching layer. Both the index matching layer and the SiO2 layer are deposited using a wet method.

[0034] US Pat. Nos. 5,993,343 and 5,993,523 disclose the use of index-matching polymer layers in touch screen applications to reduce scattering and other optical properties due to the presence of ITO gridlines. [Prior art documents] [Patent documents]

[0035] [Patent Document 1] U.S. Patent No. 8,653,509 [Patent Document 2] US Patent Application Publication No. 2017 / 0207411 [Patent Document 3] U.S. Patent No. 9692005 [Patent Document 4] U.S. Patent No. 8,829,501 [Patent Document 5] Chinese Patent No. 202183376 [Patent Document 6] U.S. Patent No. 10,141,535 [Patent Document 7] U.S. Patent No. 8,941,143 [Patent Document 8] U.S. Pat. No. 9,487,878 [Patent Document 9] U.S. Patent No. 9,159,945 [Patent Document 10] U.S. Pat. No. 7,408,296 [Patent Document 11] U.S. Pat. No. 10,068,958 [Patent Document 12] U.S. Patent No. 9,627,643 [Patent Document 13] U.S. Patent Application No. 2006 / 0108915 [Patent Document 14] U.S. Pat. No. 10,466,820 [Patent Document 15] U.S. Patent No. 7,336,036 [Patent Document 16] JP 2002-075662 A [Patent Document 17] US Patent Application Publication No. 20190363155 [Patent Document 18] International Publication No. 2018 / 017318 Brochure [Patent Document 19] US Patent Publication No. 20150123911 [Patent Document 20] US Patent Publication No. 20090188726 [Non-patent literature]

[0036] [Non-Patent Document 1] M. Kruppa et al, Information Display 4 / 19, p.14‐18(2019) [Non-Patent Document 2] Bechert et al, “Flexible and highly segmented OLED for automobile applications”, Proc. Of SPIE,Vol.10687,SPIE Photonics Conference Europe,2018 Summary of the Invention [Problem to be solved by the invention]

[0037] In order to reduce or eliminate the visibility of the power feeds that must be placed in the path of the optical radiation, the reflectance difference (D) between the areas of the transparent substrate where the power feeds are placed and the areas of the transparent substrate where the gaps between the power feeds are located is R It is highly desirable for the power feed to be 5% or less, and preferably 1% or less. Meeting these requirements results in a device in which the power feed is either invisible or has a much reduced visibility. [Means for solving the problem]

[0038] Important features include: an OLED device comprising an array of bottom-emitting OLED segments disposed on a common transparent substrate, individual OLED segments separated by non-emissive gaps, each OLED segment defined by a transparent bottom electrode segment and a top electrode and a light-emitting organic layer between the top and bottom electrode segments, each split bottom electrode electrically connected to an individual power feed, at least a portion of said power feed being disposed in an emitting light path between the bottom electrode segment and the transparent substrate, and at least one refractive index-reducing material disposed between said split bottom electrode and said transparent substrate.

[0039] In the OLED device, the index-reducing material is disposed between the lower surface of the bottom electrode segment and the upper surface of the power feed, and / or between the lower surface of the power feed and the upper surface of the transparent substrate, and / or in the lateral spaces separating the individual power feeds. Any of these possible locations are suitable and can be combined in whole or in part. In some embodiments, the index-reducing material forms a uniform or patterned layer disposed on the upper surface of the power feed and under the bottom electrode(s). In other embodiments, the index-reducing material can be patterned such that it is disposed only in the lateral spaces between the power feeds.

[0040] In any of the above OLED devices, the index-reducing material is a continuous layer disposed between the lower surface of the bottom electrode segment and the upper surface of the power feed. A uniform layer may be patterned to be disposed only in the light-emitting area of ​​the OLED device and not extend beyond the sealing area of ​​the OLED device. The index-reducing material may additionally be disposed in lateral spaces separating the individual power feeds.

[0041] In any of the OLED devices, there is an additional insulating layer disposed between the upper surface of the power feed and the lower surface of the bottom electrode segment. The insulating layer may be disposed between the index-reducing material and the lower surface of the bottom electrode segment.

[0042] In any of the above OLED devices, a reflectance difference (D) between an area of ​​the transparent substrate where the power feeds are located and an area of ​​the transparent substrate where the gaps between the power feeds are located R The refractive index R of the power feed is 5% or less. I and the refractive index R of the refractive index reducing material I Ratio to (High R I / low R I ) can be in the range of 1.00 to 1.06.

[0043] In any of the above OLED devices, the index reducer includes two or more inorganic materials with different refractive indices. The power feed may be formed from a conductive metal oxide and the index reducer is a mixture of Nb2O5 and SiO2, or the index reducer includes a suspension of inorganic particles in an organic polymer. The power feed may be formed from a conductive metal oxide and the index reducer may be a mixture of inorganic nanoparticles suspended in a polymer matrix including a polymeric siloxane with high molecular weight organofunctional groups.

[0044] In any of the above OLED devices, all of the OLED segments in the array emit the same color light, preferably red light.

[0045] In any of the OLED devices, some of the OLED segments emit light of a different color than other segments. At least one of the OLED segments in the array may be disposed within and entirely surrounded by another OLED segment.

[0046] In any of the above OLED devices, the index reducing material is in direct contact with at least one surface of the power feed. The index reducing material is electrically insulating.

[0047] In some of the OLED devices, the power feeds are disposed on a transparent substrate and the layer of index-reducing material is disposed over the power feeds and below the lower surfaces of the electrode segments, or the layer of index-reducing material is disposed over the power feeds, below the lower surfaces of the electrode segments, and between the lateral spaces separating individual power feeds.

[0048] All of the OLED segments in any of the above OLED devices are at least two-stack OLEDs, and preferably three or more stacks. [Brief description of the drawings]

[0049] [Figure 1] 1 is a top-view photograph of a prior art bottom-emitting split OLED device showing the power feeds to the individual OLED segments located below the electrode segments and in the optical path of the emitted light. [Figure 2A] 1 is a top view of a partial section 100 of a split OLED device 200. FIG. [Figure 2B] FIG. 2 is an end view of a partial section 100. [Figure 2C] 2 is another end view of the partial section 100. FIG. [Figure 3A] FIG. 2 is a top view of a complete split OLED device 200 according to the present invention. [Figure 3B] 200 is an end view. [Figure 3C] FIG. 2 is another end view of 200. [Figure 4] FIG. 3 shows a cross-section of a split OLED device 300 of the present invention. [Diagram 5] FIG. 4 shows a cross-section of a split OLED device 400 of the present invention. [Figure 6] FIG. 5 shows a cross-section of a split OLED device 500 of the present invention. [Figure 7] FIG. 6 shows a cross-section of a split OLED device 600 of the present invention. [Figure 8] FIG. 7 shows a cross-section of a split OLED device 700 of the present invention. [Figure 9] FIG. 8 shows a cross-section of a split OLED device 800 of the present invention. [Figure 10] FIG. 10 is a cross-sectional schematic diagram of a two-stack OLED formulation 1000. [Figure 11A] FIG. 9 is a top view of a split OLED device 900 of the present invention, in which some segments are completely surrounded by other segments. [Figure 11B] 900 is an end view. [Figure 11C] 11B is a cross-sectional view of 900 taken along a different axis than FIG. 11B. [Figure 12A] FIG. 2 is a top view of a split OLED device of the present invention in which some segments are completely surrounded by other segments. [Figure 12B] FIG. 12B is a top view showing the layout of the power feeds in the portion of FIG. 12A prior to deposition of the electrode segments. [Figure 12C] FIG. 12C is an enlarged view of a portion of the power feed layout shown in FIG. 12B. [Figure 13] 1 is a top view photograph of a bottom-emitting split OLED device of the present invention in which the power feeds to the individual OLED segments, located below the electrode segments and in the optical path of the emitted light, are obscured due to the presence of a refractive index reducing material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] For purposes of this disclosure, the terms "over" or "above" mean that the structure concerned is located above another structure, i.e., opposite the substrate. "Top" or "upper" refers to the side or surface furthest from the substrate, and "bottom" or "lower" refers to the side or surface closest to the substrate. Unless otherwise noted, "over" should be interpreted as either the two structures may be in direct contact or there may be an intermediate layer between them. It should be understood that a "layer" has two sides or surfaces (top and bottom), there may be multiple layers, and is not limited to a single layer. "LEL" always refers to a single light-emitting layer. "Unit" generally refers to at least one layer that can be considered to act as one single light source, and a unit may equate to a single LEL, may include one LEL associated with other non-emissive layers, or may have multiple LELs with or without additional layers. A light-emitting unit is a group of one or more LELs separated from another light-emitting unit by a charge-generating layer (CGL). Therefore, if an OLED device does not have a CGL, there is no light-emitting unit, even if it has multiple LELs. Such a device is often called a "one-stack" device. If an OLED device has two light-emitting units separated by a CGL, it can be called a "two-stack" device. A stacked OLED can have multiple units or a combination of units and LELs that together make up the total light emission.

[0051] R indicates a layer or unit that emits primarily red light (>600 nm, preferably in the range 620-660 nm), G indicates a layer or unit that emits primarily green light (500-600 nm, preferably in the range 540-565 nm), and B indicates a layer or unit that emits primarily blue light (<500 nm, preferably in the range 440-485 nm). It is important to note that R, G, and B layers may emit some light outside the ranges indicated, but the amount is always less than the primary colors. Y (yellow) indicates a layer or unit that emits large amounts of both R and G light, and much less B light. Unless otherwise noted, wavelengths are expressed in vacuum, not in situ.

[0052] The OLED light emitting elements of the present invention may be a single LEL, a one-stack OLED, a two-stack OLED, or three or more OLED stacks and may emit a single color or multiple colors. If a monochromatic light output is desired or if the color temperature of the light output needs to be adjusted or changed, color filters may be used to remove unwanted wavelengths.

[0053] An OLED light-emitting LEL or unit can produce a single "color" of light (i.e., a mixture of two primary colors such as R, G, B, Y, or cyan, or W (white)). An individual OLED light-emitting unit may have a single light-emitting layer or multiple light-emitting layers (either directly adjacent to each other or separated from each other by intermediate layers). An individual light-emitting unit may also include various types of non-emissive layers known in the art, such as hole-transporting layers, electron-transporting layers, blocking layers, etc., to facilitate light emission and provide desired effects such as managing charge transfer across the light-emitting unit. A single color of light can be produced in an OLED unit by a single layer with one or more emitters of the same color, or multiple layers each with the same or different emitters whose primary emission falls within the same color. The single color provided by the OLED unit may be a combination of two primary colors, in particular a yellow-emitting OLED unit that produces a combination of R and G light. In this case, yellow counts as a single color.

[0054] Stacked OLED devices can produce light of a single color or more than one color (multimodal). For example, multimodal OLEDs produce white light with roughly equal amounts of R, G, and B light. Generally, the CIE x , CIE y corresponds to a value of approximately 0.33,0.33. White light, even though it does not contain equal amounts of R, G, and B light, can generally be produced in an OLED by having three separate R, G, and B emitting layers, two separate emitting layers such as blue and yellow, or a single white emitting layer. Red-emitting OLEDs are generally classified as having a red emitting layer, which is the CIE x、 CIE y The value is about 0.6 to 0.7, 0.2 to 0.35. The OLED of the present invention utilizes the microcavity effect to increase the emission of light of the desired color.

[0055] In certain applications, such as automotive tail lights used to signal braking, stopping, turning, etc., the light output of the OLED used must be selected to meet all government regulations and SAE or industry standards applicable to that application, particularly in terms of color and brightness. Additionally, the size and dimensions of the split OLED device must be selected to meet all appropriate government regulations and industry standards applicable to the particular application. In such applications, the preferred emission color is red.

[0056] A split OLED device, consisting of multiple individual OLED segments on a common substrate, can have any shape as desired. A split OLED device can be entirely flat or planar, have multiple planar surfaces at angles to each other, entirely curved, or a mixture of planar, angled, and curved surfaces. A split OLED device is often mounted in a housing or part of a module, along with the necessary external power connections and control elements to provide signals or power to the individual segments. The housing or module will usually have a transparent portion that transmits the light of the OLED device and protects it from the outside environment. The housing or module may also have an internal reflector or light guide to direct the light emission as desired. The entire housing or module containing the split OLED device can be hermetically sealed.

[0057] In a split OLED device, each OLED segment is not subdivided and is powered by a single source and signal, desirably having uniform emission across the active area of ​​the segment. Split OLED devices with an array of individually controlled segments may be used for lighting purposes, where all segments are activated simultaneously to provide uniform emission (except for the gaps between the segments). The emission of all segments may be constant, dimmed all at once, brightened all at once, or flashing. Alternatively, split OLED devices may have each segment activated individually and independently in some pattern. This pattern may include some segments being fully lit, some segments being at intermediate brightness levels, and some segments being off. The pattern may be constant over a period of time, or it may vary such that individual segments are turned on and off in a time-based or location-based sequence. Because split OLED devices are not high-resolution displays and are typically intended to be viewed from a significant distance, the individual OLED segments may be activated in a similar manner to the individual pixels of a high-resolution display (typically with an emission area of ​​0.1 mm). 2Preferably, the total light-emitting area is 500 cm 2 In the small split OLED devices shown below, the individual OLED segments are at least 1 mm 2 , preferably at least 3 mm 2 It is desirable for the total light-emitting area to be 500 cm 2 For larger split devices, the individual OLED segments are at least 0.25 cm 2 , more preferably at least 1.0 cm 2 , and most preferably at least 10 cm 2 The radiation area should be 1.0 mm.

[0058] The individual OLED segments can be of any shape or area as desired. In general, the segments form a packed array to minimize the non-emitting space between the individual segments. Desirably, the array is a regular array so that the spacing between the segments is uniform, providing a smooth appearance. The array can take any overall form in terms of shape, and does not have to be square or rectangular, but can be circular, elliptical, triangular, or polygonal. In some designs, some areas of the array are regular with uniform spacing between each other, and another part of the array is irregular. For example, in a square array, the outside of the array has small square segments arranged in a uniform pattern, while the inner area has one large star-shaped segment right in the center, surrounded by a large non-emitting area. Similarly, the shape of the individual OLED segments in the array is not limited, but can be square, rectangular, circular, elliptical, triangular, or polygonal, or irregular as desired.

[0059] Furthermore, the OLED segments in the array need not all be the same shape, but may have a mixture of shapes, such as interlocking triangles and hexagons. Preferred are packed arrays of only triangles, only parallelograms, or a mixture of triangles, hexagons, and trapezoids. The areas of the individual segments need not all be the same, and the array may be comprised of a mixture of large and small segments. The individual segments in the array need not all emit the same color (although each individual segment emits a single color), and segments emitting different colors may be arranged in a particular pattern in the array.

[0060] FIG. 2A shows a top view of a (partial) section 100 of a bottom-emitting split OLED device. For clarity, only the bottom of the entire device is shown in this view. There are four rectangular electrode segments 1, 2, 3 and 4 in an array, each of which will ultimately define an OLED segment. Above a transparent substrate 10 are (in order): a layer 20 of refractive index-reducing material (which in this example is the same size as the substrate), four individual power feeds 11, 12, 13 and 14, an insulating layer 30, and four split electrodes 1, 2, 3 and 4. Power feed 11 is electrically connected to split electrode 1 through via 31 and has a contact area 21 that extends beyond the edge of electrode segment 3 towards the edge of substrate 10. Power feed 13 is electrically connected to split electrode 3 through via 33 and has a contact area 23 that also extends beyond the edge of electrode segment 3. Power feed 12 is electrically connected to split electrode 2 through via 32 and has a contact area 22 that extends beyond the edge of electrode segment 4 towards the edge of substrate 10. Power feed 14 is electrically connected to split electrode 4 through via 34 and has a contact area 24 that also extends beyond the edge of electrode segment 4. These power feeds are all coplanar but laterally spaced apart from one another so that they do not touch. Outer power feeds 11 and 12 pass underneath electrode segments 3 and 4, and inner power feeds 13 and 14 also pass underneath but only extend slightly beyond the edges of electrode segments 3 and 4.

[0061] FIG. 2B is an end view of the lower section 100 from the edge closest to electrode segments 3 and 4 in FIG. 2A. Illustrated are (in order) transparent substrate 10, layer of index-reducing material 20, and, from left to right, contact areas 21 (directly behind power feed 11), 23 (directly behind power feed 13), and, on the other side, contact area 24 (directly behind power feed 14), and contact area 22 (directly behind power feed 12). The bottom surfaces of power feeds 11, 13, 14, and 12 are in direct contact with the top surface of layer of index-reducing material 20. Above power feeds 11, 13, 14, and 12 are transparent insulating layer 30 and electrode segments 3 (directly behind 1) and 4 (directly behind 2). Vias 31, 33, 34, and 32 in insulating layer 30 allow electrical connection between power feed 11 and electrode segments 1, 13 and 3, 14 and 4, and 12 and 2, respectively. There are gaps or spaces (not visible) between electrode segments 3 and 4 as well as between 1 and 2. In FIG. 2B, all of the power feeds 11, 13, 14, 12 lie in the same relative plane, are laterally separated and are electrically isolated from one another at gaps 85 by insulating layer 30.

[0062] Figure 2C is an end view of lower section 100 as viewed from the left side of Figure 2A (i.e., the side closest to electrode segments 1 and 3). It shows (in order) transparent substrate 10, layer of index-reducing material 20, and long power feed 11 directly in front of short power feed 13. Long power feed 12 and short power feed 14 are not visible in this view as they are directly behind on the far side of the device. Power Feed Together, 11 and 13 extend beyond the edge of electrode segment 3 to form contact areas 21 and 23 (not visible), and also extend beyond the edge of electrode segment 4 (not visible). Power FeedAlso not visible are the corresponding contact areas 24 and 22 formed by 14 and 12. There are gaps between electrode segments 1 and 3 and between 2 and 4. The view also clearly shows that the outer power feeds 11 and 12 pass under the sides of electrode segments 3 and 4, and that the inner power feeds 13 and 14 also pass under, but only extend slightly beyond, the edges of electrode segments 3 and 4.

[0063] FIG. 3A shows a top view of an entire bottom-emitting split OLED device 200 including the partial lower section 100 shown in FIG. 2A. Starting at 100 (see FIG. 2A), there is a pixel-defining layer (PDL) 40 along the outer edge as well as the gaps between electrode segments 1, 2, 3, and 4. Above the PDL 40 and electrode segments 1, 2, 3, 4 is an OLED layer 50 for light emission as well as a top electrode 60. Along one edge there is an extension of the top electrode 60 to the edge of the substrate 10 forming a contact area 260. Above the top electrode 60 is an encapsulant 70 exposing the bottom electrode contact areas 21, 23, 24, 22 and the top electrode contact area 260. In 200, the PDL fills the gaps separating electrodes 1, 2, 3, 4 so that not only is there no electrical contact between the electrodes, but it also protects the sides of the electrode segments from contact with the top electrode 60. There is no light emission from the area above the PDL 40. This results in a non-emitting gap 80 between the light-emitting areas 75. Furthermore, even though power feeds 11 and 12 pass underneath electrode segments 3 and 4, there is no electrical contact because they are separated by insulating layer 30. However, power feeds 11 and 12 are directly in the optical path of the emitted light through electrode segments 3 and 4.

[0064] FIG. 3B is an end view of OLED device 200 from the bottom of FIG. 3A (i.e., the portion closest to electrode segments 3 and 4). Starting with bottom section 100 (see FIG. 2B), there is a pixel-defining layer (PDL) 40 along the outer edge as well as the gap between electrode segments 3 and 4 (with 1 and 2 directly behind). Above the PDL 40 and electrode segments 1, 2, 3, 4 is an OLED layer 50 for light emission and a top electrode 60. Along one edge is an extension of top electrode 60 to the edge of substrate 10 to form contact area 260. Above top electrode 60 is an encapsulant 70, exposing bottom electrode contact areas 21, 23, 24, 22 and top electrode contact area 260. In 200, the PDL fills the gap separating electrodes 1, 2, 3, 4 to ensure there is no electrical contact between them, and protects the sides of the electrode segments from contact with top electrode 60.

[0065] Figure 3C is an end view of OLED device 200 as viewed from the left side of Figure 3A (i.e., the side closest to electrode segments 1 and 3). Starting with bottom section 100 (see Figure 2C), pixel-defining layer (PDL) 40 is present along the outer edge as well as in the gap between electrode segments 1 and 3 (with 2 and 4 directly behind). Above electrode segments 1, 2, 3, 4 are OLED layers 50 for light emission as well as a top electrode 60. Along one edge is a power feed to the edge of substrate 10. 11、12、13、14 , forming contact areas 21, 23, 24, 22. Over the top electrode 60 is an encapsulant 70, exposing bottom electrode contact areas 21, 23, 24, 22 and top electrode contact area 260 (not visible). It can be clearly seen in this view that even though power feeds 11 and 12 pass underneath electrode segments 3 and 4, there is no electrical contact between them because they are separated along their entire length by insulating layer 30.

[0066] In OLED device 200, each OLED segment forming the array corresponds to its bottom split electrode. However, the light-emitting areas 75 of the OLED segments may not correspond exactly to the size of the electrode segments, and there may be some portions of the OLED segments above the electrode segments that are non-emitting. For example, some portions of the PDL may be patterned to overlap portions of the top surface of the electrode segments to prevent light emission from the covered portions. When power is applied to one of the contact areas (e.g., 21), the power passes through the power feed (i.e., 11 under electrode segment 3) and through vias (i.e., 31) in insulating layer 30 to the appropriate electrode segment (i.e., 1). The power then causes light emission in the OLED layer 50 in the area above the electrode segment. Because the OLED segments are bottom-emitting, the emitted light passes through the transparent electrode segments, the insulating layer (if present), any power feeds located directly below the electrode segments, the index-reducing material, and the transparent substrate. The light-emitting areas 75 corresponding to the bottom split electrodes are separated between segments by non-emitting gaps 80 and also along the outer edge of the device. The non-emitting gaps 80 may partially overlap the electrode segments.

[0067] Typically, the conductive material of which the power feed is constructed has a relatively high refractive index, while the surrounding materials may have a different, often much lower, refractive index. This difference in refractive index at the interface between the power feed and the insulating layer can result in a visible difference in the light emission compared to areas without the power feed, see FIG. 1. By incorporating an index-reducing material into a split OLED device, where the index of refraction of the index-reducing material is close in magnitude to that of the power feed, the visible difference in the light emission due to the presence of the power feed in the light path can be eliminated or at least reduced.

[0068] In Figures 3A-3C, layer 20 of index-reducing material is shown as a continuous layer beneath the underside of power feeds 11, 12, 13, 14. As shown, layer 20 is the same size as transparent substrate 10 and completely covers it. However, layer 20 may be patterned to be smaller than transparent substrate 10 and specifically present only in the encapsulated areas of the split OLED. Alternatively, the index-reducing material may be patterned to be present only beneath the power feeds. In this case, the lateral space between the index-reducing material and the overlying power feeds may be filled with an insulating, transparent material.

[0069] At 200, the power feed is patterned on the top surface of the layer of index-reducing material 20 such that only the bottom surface of the power feed is in direct contact with the index-reducing material. This is easy and simple to manufacture, but may not provide sufficient visibility reduction in all cases.

[0070] Figure 4 shows Power Feed 3 shows an embodiment 300 of an OLED device in which power leads 11, 13, 14 and 12 are disposed directly on a transparent substrate 10 with the lateral spaces between them filled with an index-reducing material 20. In particular, the gaps or spaces between power leads 11, 13, 14 and 12 are not filled with an insulating layer 30 as in device 200, but are instead filled with an index-reducing material 20. In this manner, the index-reducing material 20 is adjacent to the side (vertical) walls of the power leads and helps to reduce visibility due to refractive index differences. The thickness of 20 is approximately 100 nm, and the thickness of the power leads 11, 13, 14 and 12 is approximately 100 nm. Power Feed The height is adjusted so that it is not higher than the top surface of the Power Feed / Does not prevent the creation of vias 31, 33, 34, 32 in insulating layer 30 on top of the index reducer. The index reducer 20 may be the same or different in each of the lateral spaces between the power feeds. In 300, the index reducer is in direct contact with the vertical faces of the power feeds.

[0071] Figure 5 shows an embodiment 400 of an OLED device that is the same as that shown in Figure 4, except that the height of the layer of index-reducing material 20 (above the substrate 10) is greater than the height of the power feeds 11, 13, 14 and 12. In this embodiment, all of the lateral gaps between the power feeds are filled with the index-reducing layer 20. There is still an overlying insulating layer 30 between the top surface of the index-reducing layer 20 and the bottom surface of the electrode segments. In this embodiment, vias 31, 33, 34, 32 extend through both the insulating layer and the index-reducing layer 20. The presence of the index-reducing material in direct contact with three sides of the power feeds (top and two vertical sides) further reduces the visibility of the power feeds.

[0072] Figure 6 shows an embodiment 500 of an OLED device that is the same as that shown in Figure 5 except that the insulating layer 30 has been completely replaced by the index-reducing layer 20. The entire vertical distance between the upper surface of the transparent substrate 10, on which the power feeds are located, and the lower surface of the electrode segments is filled with the index-reducing layer 20. In this embodiment, vias 31, 33, 34, 32 extend through the index-reducing layer 20.

[0073] Figure 7 shows an embodiment 600 of an OLED device that is the same as that shown in Figure 6 except that the PDL layer 40 has been completely replaced by an index-reducing layer 20. In 600, there is no PDL. As shown, the gaps between the electrode segments and the exterior are filled with an index-reducing material as layer 20. The index-reducing layer 20 may be patterned to form wells into which the electrode segments are then formed. Alternatively, the electrode segments may be patterned over a uniform index-reducing layer 20, after which additional index-reducing material is added and patterned to fill the gaps and edges.

[0074] 8 shows an embodiment 700 of an OLED device similar to 600, except that the electrode segments are patterned directly on the index-reduction layer 20 and the organic layer 50 is formed directly on the electrode segments. In this case, the light-emitting organic material fills the gaps between the electrode segments. Whenever one of the electrode segments is activated, some light emission (crosstalk) will occur from the organic layer located in the gaps between the segments. While light emission from the gaps between the segments may be undesirable in some applications, it may not be a problem or concern in other applications, especially in monochromatic devices where clear definition and separation of individual segments is not expected or required.

[0075] As shown at 700, in this area, the organic light-emitting layer 50 is present between the top electrode 60 and the edge of the split electrode, so there will also be light emission along the outer edge of the split electrode. This may not be a problem or concern in some applications since the device is bottom emitting and the sides are typically encapsulated or covered with an opaque material. If this is a problem, the organic layer 50 along the outer edge of the device may be patterned so that it is not present in this region, or may be removed after deposition, for example by laser ablation. However, to protect against shorts between the top electrode 60 and the electrode segments, the top electrode 60 may need to be patterned so that it does not extend beyond the outer edge of the organic layer 50 on the electrode segments, or the space where the organic layer 50 was removed may need to be refilled with an insulating material such as PDL.

[0076] In any of the embodiments shown in Figures 4-8 where the index-reducing material is present in the lateral spaces between the power feeds or between the power feeds and the bottom electrode segments, it is important that the index-reducing material be electrically non-conductive (insulating). It is necessary for the index-reducing material 20 to be sufficiently non-conductive so that no electrical shorts are created between the power feeds or between the power feeds and the bottom electrode segments.

[0077] In any of the embodiments shown in Figures 4-8 (devices 300-700), there may optionally be an additional layer of index-reducing material 20 (as in Figures 3A-3C for 200) between the power feed and the transparent substrate 10. Further reduction in visibility can be achieved by having a layer of index-reducing material not only below the power feed, but also on the sides and / or top.

[0078] 3-8, OLED layer 50 extends uniformly across all of the electrode segments and the gaps between them and is common to all of the individual OLED segments, which is desirable in applications where all of the individual OLED segments have the same emission, as this reduces manufacturing complexity.

[0079] However, having a common OLED layer can result in some degree of crosstalk even when the electrode segments are electrically isolated (i.e., by PDL 40 in FIG. 3B). Crosstalk is when the luminance of the emitted light provided by one segment is unintentionally affected by another segment. This is undesirable in some applications because it can degrade the overall quality of the device's emission, as the affected segment no longer provides the exact luminance intended. In many cases, it is desirable for the amount of crosstalk between pixels to be 25% or less, preferably 10% or less. The amount of crosstalk observed depends on many factors, including the size of the segments, the width of the gap between the segments, the thickness of the luminescent OLED layer, and whether the OLED layer is part of a microcavity.

[0080] Crosstalk can occur through both optical and chemical / electrical mechanisms. Optical processes that can increase the amount of crosstalk include light scattering and waveguiding within an OLED device. Some chemical / electrical processes that can increase crosstalk include lateral carrier movement from one electrode segment to an adjacent inactive segment through one or more common OLED layers. There are known strategies to reduce or mitigate crosstalk that can be applied if the amount of observed crosstalk is problematic for a particular application.

[0081] One approach to reducing crosstalk is to not use a common OLED layer across multiple electrode segments. For split electrodes that must be electrically isolated from one another, the OLED layer may be divided into segments that correspond to the individual electrode segments by pixel-defining layers.

[0082] Figure 9 shows an OLED device 800 in which the OLED layers on each electrode segment are separated by a pixel-defining layer in the gaps between the electrode segments. In this embodiment, an index-reducing layer (20) is located between the bottom surfaces of the power feeds (11, 12, 13, 14) and the transparent substrate (10), and an insulating layer (30) is located above and between the power feeds (11, 12, 13, 14) and below the electrode segments (1, 2, 3, 4). Device 800 is similar to 200 (see Figure 3B), except that the PDL 40 is extended above the top surfaces of the electrode segments both along the outer edges as well as between the electrode segments. The walls created by the extended height of the PDL 40 create a well that contains the OLED layers. In particular, the increase in height of the PDL 40 along all sides of electrode segments 3 (directly behind segment 1) and 4 (directly behind segment 2) creates an OLED segment 50A above 3 (directly behind OLED segment 50B above 1) and an OLED segment 50C above 4 (directly behind OLED segment 50D above 2). Because there are no common layers between the OLED segments (except for the common top electrode 60 as shown), crosstalk can be significantly reduced. The PDL layer 40 can be patterned to not only fill the space between the electrode segments, but also overlap the edges of the electrode segments, which results in a larger gap between the segments and a smaller light emitting area.

[0083] The use of extended PDL layers to define segments as shown at 800 can also be combined with various power feed / index reducer / insulator layer arrangements as shown in FIGS.

[0084] It should be noted that there are two general approaches to creating OLED devices in which some segments emit a different color of light than other segments. One approach uses OLED segments that emit the desired color directly. The embodiment shown in Figure 9 is useful for such applications. Alternatively, all OLED segments can emit white or multimodal light, and color filters can be used to make the emission of each particular segment the desired color.

[0085] The transparent substrate 10 can be glass (including flexible glass) or a polymeric material. It is generally flat with a uniform thickness. The top surface of the substrate is the one that faces the OLED. The substrate will be part of the overall encapsulation of the OLED and therefore must be sufficiently impermeable to air and water for the OLED to have a desired lifetime. The substrate can be rigid or flexible. The substrate can have various types of undercoat layers (i.e., planarization layers, light management layers, etc.), which can be patterned or unpatterned, and can be located on either the top or bottom surface. Rigid or soft glass is preferred.

[0086] There should be only one power feed per segment. In some cases, the power feed may be split into two or more sub-power feeds that connect to the same electrode segment at different locations. In some cases, two or more separate but commonly operated power feeds (considered equivalent to a single power feed) may be connected to a single segment. For example, a driver with a maximum output of 10 mA may be connected to a 20 cm 2 to obtain the desired light output of 1 mA / cm 2If more than one segment is required, then the segment needs two power feeds (one from each driver, or one each from the two channels of a multi-channel driver). Such an arrangement helps to distribute power more evenly over the segment and to reduce IR drop. However, in some cases, the same power feed may be used for two or more segments. Segments that share a common power feed are considered equivalent to one segment, since they cannot be activated independently and will emit light in common.

[0087] On the outside of the encapsulant are external contact areas (also called contact pads) that are electrically connected to each of the power feeds inside the encapsulant. The figure shows the extensions of the power feeds outside the encapsulant forming the contact areas, e.g., 21-24, but it is possible to selectively remove the encapsulant over the power feeds to make electrical contact through the encapsulant. A controlled power source is then electrically connected (i.e., by soldering or ACF) to these contact areas and supplies power as required to the power feeds and segment electrodes within the encapsulant. By supplying the appropriate amount of power to the contact areas for the appropriate period of time, the OLED segments will emit light at the desired brightness for that period of time. The power supplied to the external contact pads is determined by a controller or driver.

[0088] The location and distribution of the individual power feeds across the surface of the substrate depends on the design of the segment array. Some power feeds may be located along non-emitting areas (i.e., under gaps and / or outer edges of the device), while other power feeds may be located under the segments and in the optical path. In some designs, some segments may have no power feeds located under them, while other segments have multiple power feeds. The inclusion of an index-reducing material can make the emission from each segment of the device appear more uniform.

[0089] It is important that the IR drop along the power feed is equivalent for all OLED segments, regardless of their distance from the external power source or the size of the OLED segments (larger segments require more power to operate than smaller segments). However, the IR drop can be minimized by adjusting the width (parallel to the substrate) or height (above the substrate) of the power feed. Thus, in such cases, not all power feeds have the same width and height dimensions, which may vary according to their length as well. Furthermore, not all of the power feeds have the same structure. For example, shorter power feeds may be made of a conductive metal oxide, while longer power feeds may have an auxiliary electrode or be metallic, such as a thin layer of Ag.

[0090] Ideally, the power feed is as transparent as possible. The power feed may be constructed of any conductive material that can be patterned. For example, the power feed may be made from metals such as silver or copper, conductive metal oxides such as ITO, AZO, IZO, GZO, ZnO, TiN, SnO2, organic materials such as PEDOT:PSS, CNT (carbon nanotubes), graphene, conductive particles such as silver, nickel, copper suspended in a polymer binder (conductive ink), or any combination of these materials. Inherently opaque conductive materials (i.e., silver) may be in the form of nanowires or meshes so that there are openings in the structure of the power feed that allow some light through, or are thin enough not to be opaque. Ideally, the power feed should have a resistivity of less than 25 ohms / square, preferably less than 15 ohms / square.

[0091] The power feed is preferably constructed from a conductive metal oxide, with ITO being particularly preferred. However, ITO is known to have a limited degree of lateral electrical conduction. If desired, a power feed formed from a conductive metal oxide may have an auxiliary electrode (e.g., an overcoat or sublayer of a conductive metal such as metallic silver or aluminum, or a conductive metal mesh) that helps minimize IR drop along some or all of its length.

[0092] When placed in the light emission path of a split OLED device, the power feed has a different refractive index (R I ), which may be visible. In optics, the refractive index (also called the coefficient of refraction) of a material is a dimensionless number (n) that describes how fast light passes through the material. The refractive index is defined as n=c / v, where c is the speed of light in a vacuum and v is the phase velocity of light in the medium. The refractive index determines how much light bends, or refracts, when it enters a material and can be described by Snell's law of refraction. When there is an interface between two materials, the relative difference in their refractive indices determines how much light is refracted. The relative refractive indices also determine how much light is reflected when it reaches the interface, and the critical angle for total internal reflection. The R of two materials in contact I The greater the difference, the greater the amount of light refracted, making the interface between the materials more visible. I The closer the R is, the less the light is refracted, making the interface less noticeable. I Only the difference in R is important, and it does not matter which material is high or low. I It should be noted that depends on the wavelength of light.

[0093] The table below shows typical R values ​​for materials commonly used in OLED devices. I A list of values. TIFF0007624064000001.tif94170 R above I The values ​​are representative only and the actual R IIt is important to note that the value depends on its exact composition, how it is prepared, whether it is thin film or bulk, the wavelength of light, etc. However, the actual R I Methods for measuring values ​​are well known.

[0094] In some cases, the power feed is a single, easily identifiable R I In such cases, the effective R value must be determined experimentally or calculated. I It may be necessary to determine the value of R I For mixtures of materials with known R values, calculation methods can be used. As another example, metal may be used as the power feed in the form of a thin layer that is at least semi-transparent. In this case, the effective R I The value can be determined experimentally or calculated. Similarly, in applications where the power feed has openings in its structure to allow light to pass through, the effective R I Another example is a conductive ink, which is a suspension of conductive particles in a binder. This is deposited and the binder cured or partially removed to determine the effective R I Form the power line as a thin film that can measure the effective R I Even if one or both of the R and R are undetermined or unknown, the relative R can be determined by simple optical measurements as light passes through the interface. I It is possible to determine R I If they are relatively consistent there will be little refraction, but as the difference increases the amount of refraction will increase.

[0095] As an example, a glass (R I =1.5) or PET (R I = 1.6) substrate. I =1.8) When using a power feed, the R I The mismatch in the material (usually R I = 1.4 to 1.6) between the polymer and the substrate IThe ITO / substrate interface refracts light in a different way than the polymer / substrate interface, making the power feed visible. I By reducing the mismatch, the power feed can be made less noticeable.

[0096] Desirable index-reducing materials and layers thereof are those that can be formed and patterned as thin films. In many embodiments, the index-reducing layer or material will have a refractive index similar to that of the power feed material, although an exact match is not required. I Ideally, a high R I Materials with low R I Mismatch between materials with high R I / low R I The ratio of the refractive index-reducing layer or material to the refractive index-reducing layer (Ratio of the refractive index-reducing layer or material to the refractive index-reducing material) should be in the range of 1.00 to 1.06, or preferably in the range of 1.00 to 1.03. It is not important which material is high and which is low. The refractive index-reducing layer or material must be solid to be used in the device; liquids or oils are not suitable.

[0097] The index reducer and its layers should be as transparent as possible. Desirably, the index reducer and its layers have a transmittance of 90% or more. The index reducer should not scatter light. If the index reducer contains particles, the particles themselves should be small enough so that light is not scattered. The maximum amount of light scattering by the index reducer layer or material should be 10% or less (measured in-line with the source light perpendicular to the index reducer layer or material and compared to the total light measured with an integrating sphere).

[0098] In many applications it is important that the index reducer and its layers are non-conductive. If the index reducer is in direct contact with an electrically conductive power feed, the layers in direct contact must be electrically insulating to prevent electrical Power FeedTo prevent internal short circuits between the upper electrode segment and the lower electrode segment, the refractive index-lowering layer should have an electrical resistance of 1 megohm (MΩ) or more, and more preferably 2 megohm or more.

[0099] Polymer R I It is well known that the effective R can be adjusted by using appropriate functional groups or structural moieties in the polymer backbone or by incorporating other polymers. I High R I The particle concentration can be easily adjusted to achieve low R I High R in polymer binder I It is also well known that suspensions of inorganic or organic particles of R can be used as refractive index reducing layers. I Tunable polymers can have some amount of removable solvent to control the viscosity of the suspension and / or to control the stability. Such polymer solutions are generally viscous liquids and can be easily applied as thin films using known techniques such as spin coating or slot coating, or can be applied by inkjet or similar techniques and patterned using photolithography techniques. After application, curing procedures such as UV exposure, heat treatment, and solvent removal may be required to solidify the polymer.

[0100] Suitable examples of polymer-based refractive index-reducing layers or materials are nanoparticles such as nano-zirconia in a polymer matrix, or organic materials, alone or in mixtures, such as high molecular weight organofunctional siloxanes.

[0101] In some cases, the refractive index reducing polymer may contain some amount of water and / or oxygen. Since the refractive index reducing material will be contained within the encapsulation of the device, even trace amounts may adversely affect the OLED materials. Therefore, after depositing the refractive index reducing polymer but before depositing the organic OLED materials, it may be necessary to bake the device or subject it to a heat treatment, which may be performed in vacuum. If the refractive index reducing polymer is deposited in multiple steps, the heat treatment may be performed after each step or after all steps are completed. One suitable heat treatment would be to keep the device in an oven at 200 degrees C for at least 0.5 hours.

[0102] The use of inorganic materials as the refractive index reducing material or layer is preferred because heat treatment can adversely affect other parts of the device and increases the total manufacturing time. Inorganic materials are typically deposited under vacuum deposition conditions or by CVD (chemical vapor deposition), so that water and oxygen contamination are not a concern and the device can be immediately subjected to further manufacturing steps. Inorganic materials can also be patterned, if desired, by known shadow mask or photolithography techniques.

[0103] Inorganic refractive index reducing material R I Each has a different R I Co-depositing two or more different inorganic materials in a specific ratio, the effective R of the mixture is I R of the power feed I It may be desirable to align

[0104] Suitable inorganic refractive index-lowering layers or materials include metal oxides or nitrides such as zirconia, niobium oxide, titanium dioxide, silicon nitride, and mixtures thereof. In particular, Nb2O5(R I =2.34) and SiO2 (R I =1.47) is a mixture of ITO (R I = 1.82) I This mixture is transparent and non-conductive.

[0105] The index-lowering layer may be divided into two or more separate layers, each of which may be composed of a different material, if desired.

[0106] It is desirable for the index-reducing material to be in direct contact with the power feeds, although this is not strictly necessary in all cases. However, it is necessary that the index-reducing material be located at least between the lower surface of the bottom electrode segment and the upper surface of the transparent substrate and in the optical path of the light emission. This may include having lateral spaces separating individual power feeds that are located below the bottom electrode and in the optical path, even if the index-reducing material is not in direct contact with the sides of the power feeds.

[0107] In particular, the index reducer may be located on the base layer, with the intermediate material on top of the index reducer, and the power feed on top of the intermediate material. In this embodiment, the index reducer is not in direct contact with the power feed. The intermediate material is in direct contact with the R of the index reducer. I and R of the transparent substrate I Between R I Thus, the refractive index reducing material reduces the refraction between the base layer and itself, and the intermediate layer reduces the refraction between the intermediate layer and the power feed. For example, a glass (R I =1.5) and R I An overcoat of refractive index reducing material (Nb2O5 / SiO2) adjusted to RI=1.6 is used, and a layer of intermediate material (Nb2O5 / SiO2) adjusted to RI=1.7 is used. I An ITO power feed of =1.8 can be used to reduce the visibility of the power feed.

[0108] In many embodiments, the index-reducing material, in addition to reducing the visibility of the power feed, also provides electrical insulation to prevent short circuits. Power Feedand the split electrodes. The power feeds cannot make electrical contact with any other electrode segment than the electrode segment they control. Thus, in addition to the index-lowering layer or material, an insulating layer may be required to prevent shorting between the power feeds and the upper electrode segments.

[0109] The material of the insulating layer is different from the refractive index reducing material, I is the R of the power feed I The material of the insulating layer does not have to match the refractive index lowering material. However, it is desirable that the material of the insulating layer be transparent and non-light scattering, similar to the refractive index lowering material. The insulating layer should have a resistivity at least equal to or greater than that of the refractive index lowering material.

[0110] The insulating layer may be polymeric, but is preferably inorganic. Suitable inorganic insulating layers or materials include SiO2, SiN, SiON, Al2O3, TiO2, etc., and mixtures thereof.

[0111] The vertical space between the top surface of the power feed and the bottom surface of the electrode segment is preferably filled with an insulating material, including an index-reducing layer, an insulating layer, or both. The vertical distance should be greater than 0.1 microns to prevent shorting, and less than or equal to 10 microns to maintain the thinness of the device, ideally in the range of 0.2 to 1.0 microns.

[0112] The electrical connection between the power feed and the top split electrode is made through a via, which is a hole or passage in the insulating material (i.e., insulating layer, index-reducing layer, or both) that separates the power feed and the top split electrode. The via leads from the top of the power feed to the bottom or side of the split electrode. Ideally, the via connects to the split electrode at a location that corresponds to the non-emitting area of ​​the split OLED. The via may be formed by patterning the top insulating material to expose or uncover at least a portion of the top surface of the power feed. Alternatively, the via may be formed by uniformly depositing the top insulating material over the power feed and removing material over the desired portion of the power feed to expose the top surface.

[0113] The vias are filled with a conductive material. When a split electrode is deposited on top of the material, some of the material of the split electrode can fill the via and make the connection. Alternatively, the vias may be filled with a conductive material first and then the split electrode deposited on top of the filled via / insulating material. In some cases, it may be necessary to treat the power feed before depositing the insulating layer, or the filled via before depositing the split electrode, with a material that promotes electrical conductivity through the connection.

[0114] The length and area of ​​the vias are not critical, but should be sufficient to deliver the required power to the split electrodes. The vias can be of any shape along the top surface of the power feed. In particular, the vias Power Feed There may be a number of vias between the power feed and the electrode segment.

[0115] There is an array of individual electrode segments that are located on a common substrate along with other intervening layers such as refractive index-reducing layers. "Common" means that all of the OLED segments in the array share the same substrate and are fabricated together on that substrate as an array. On all sides (except those at the outer edges and corners of the device), there are non-emissive lateral gaps between the individual segments that separate them. A split OLED array differs from a tiled OLED array in which each complete individual OLED segment is fabricated separately on its own substrate, and then each complete OLED segment is mounted on a single common substrate.

[0116] In split OLED devices, the bottom electrode segment is transparent. The transparent electrode segment should transmit as much light as possible, preferably with a transmittance of at least 70% or more, more desirably at least 80%. However, in some applications (i.e., microcavity devices), the transparent bottom electrode may only be semi-transparent and have partial reflectance. The bottom transparent electrode may be made of any conductive material, but a thin layer of a metal oxide such as ITO or AZO or a metal such as Ag is preferred. In some cases, there may be an auxiliary electrode that helps distribute the charge more evenly across the area of ​​the transparent electrode. Ideally, the electrode segment should have a resistivity of less than 25 ohms / square, desirably in the range of 10-23 ohms / square.

[0117] In some embodiments, a pixel-defining layer (PDL) is present to separate a portion of one OLED segment from another OLED segment or along the perimeter of the array. For example, a PDL can be used to separate electrode segments from electrical contact and confine the organic layer to a single OLED segment or to define the perimeter of the array. In some cases, a PDL can be used to partially cover an electrode segment to prevent light emission in the PDL area (e.g., in areas where vias are located along the edges of the electrode segments). In other cases where there is no PDL layer in the gap between electrode segments (i.e., see Figures 7 and 8), there may still be a PDL located along the perimeter of the array. The PDL is preferably insulating (non-conductive).

[0118] In some embodiments, the PDL in the gaps between the electrode segments has approximately the same thickness as the electrode segments. This creates a relatively flat surface for depositing the top layer (i.e., see FIG. 3B). In other embodiments, the PDL is thicker than the electrode segments, so that a portion of the PDL extends beyond the top surface of the electrode segments (i.e., see FIG. 9), either into the gap or along the outer edge of the array. In some cases, the extended portion of the PDL will also cover a portion of the top surface of the electrode surface. In such cases, the PDL may cause undesirable light piping or light guiding. To reduce light piping, an absorbing dye may be added to the PDL. Alternatively, the PDL layer material may be opaque or black.

[0119] Suitable PDL materials may be polymeric or inorganic. Examples of suitable polymeric PDLs include acrylic polymers and polyimide polymers. Some examples of suitable inorganic PDLs include SiO2, SiN, and SiON. Ideally, the thickness of the PDL layer should be 5 microns or less, and preferably in the range of 0.2 to 3.0 microns.

[0120] Figure 10 shows a typical configuration of OLED layer types for emitting light in an OLED device 1000. There will be one or more light-emitting layers with multiple auxiliary layers that help to facilitate and control the transfer of charge between the electrodes when light is emitted. In this particular example, the bottom electrode segment is the anode and the top electrode is the cathode.

[0121] Above the transparent electrode segments there may be an optional hole injection layer (HIL, layer 501). The purpose of the HIL is to manage the transport of holes from the organic layers to the anode. Suitable hole injection materials are well known and commonly used. These layers may be mixtures of such materials and may include dopants to modify their properties. They are non-emissive and therefore do not include emissive materials. Generally there is only one HIL. The selection of the appropriate material is not critical and any may be selected based on its performance. One example of a suitable HIL material is HAT-CN.

[0122] On top of the HIL (layer 501) is disposed a hole transport layer (HTL, layer 502). The purpose of the HTL is to manage the transport of holes from the HIL to the emissive layer above. Suitable hole transport materials are well known and commonly used. These layers may be mixtures of such materials and may contain dopants to modify their properties. They are non-emissive and therefore do not contain emissive materials. There may be multiple HTLs. The selection of the appropriate material is not critical and any may be selected based on its performance. One example of a suitable HTL is NPB.

[0123] Above the HTL (layer 502) is an optional exciton blocking layer (EBL, layer 503). The emissive layer optionally emits light via the formation of excitons that have a lifetime sufficient to diffuse away from their formation site. The purpose of the EBL is to confine the excitons to the LEL and maximize light emission. Suitable exciton transporting materials are well known and commonly used. These layers may be mixtures of such materials and may include dopants to modify their properties. No emissive materials are included, as they are non-emissive. There may be multiple EBLs. The selection of the appropriate material is not critical and any may be selected based on its performance. One example of a suitable EBL is mCP.

[0124] A first light-emitting layer or unit (LEL1, layer 504) is disposed on top of the EBL (layer 503). The light-emitting layer (LEL), which is a single layer, generally comprises one or more non-emissive host compounds and one or more light-emitting dopants. Suitable host materials and fluorescent, phosphorescent and TADF light-emitting dopants for use in the light-emitting layer or unit are well known and commonly used. Light-emitting units as defined above may also be used for emission. The selection of suitable materials is not critical and any may be selected based on its performance and emission properties.

[0125] Above LEL1 (layer 504) is an optional hole blocking layer (HBL, layer 505). Emitting layers emit light by the formation of excitons, which in some cases may not form fast enough before holes migrate towards the cathode. The purpose of the HBL is to confine holes to the LEL and maximize light emission. Suitable hole blocking materials are well known and commonly used. These layers may be mixtures of such materials and may contain dopants to modify their properties. They are non-emissive and therefore do not contain emissive materials. There may be multiple HBLs. The selection of the appropriate material is not critical and any may be selected based on its performance. One example of a suitable HBL is SF3-TRZ.

[0126] Above the HBL (layer 505) is a charge generation layer (CGL, layer 506). The CGL (sometimes called a connector layer or intermediate layer) is located between the individual OLED light-emitting units and typically consists of multiple layers. This is because the CGL is structured so that when a voltage is applied, electrons and holes are generated and injected into the adjacent organic light-emitting layer. Thus, the use of a CGL can potentially convert one injected electron into multiple photons, resulting in higher brightness. In particular, it is desirable to have a CGL between each light-emitting unit in the stack. However, it is not necessary for there to be adjacent CGLs on both sides of the light-emitting unit. The top and bottom OLED light-generating units in the stack will generally only have one adjacent CGL. It is not usually necessary to use a CGL between the light-emitting unit and either the top or bottom electrode, but a CGL can be used if desired.

[0127] Many different types of CGLs have been proposed and may be used in an OLED stack. See, for example, US Pat. No. 7,728,517 and US Patent Application Publication No. 2007 / 0046189. To form a CGL, an n-p semiconductor heterojunction located at the interface of the n-type and p-type layers is typically required for charge generation. Thus, the CGL will have two or more layers. For example, n-doped organic layer / transparent conductive layer, n-doped organic layer / insulating material, n-doped organic material layer / metal oxide layer, and n-doped organic material layer / p-doped organic material layer have been reported. A preferred metal oxide for the CGL is MoO3. In some instances, the n- and p-layers may be separated by a thin intermediate layer. Often, the CGL is arranged with the n-layer close to the anode and the p-layer close to the cathode.

[0128] One desirable formulation of a CGL has three layers: an electron-transporting material doped with an n-dopant (e.g., Li), a thin interlayer of the same (but undoped) electron-transporting material, and a hole-transporting material doped with a p-dopant. Another desirable formulation of a CGL has the same type of doped ETL with an interlayer of a different electron-transporting material and an electron-deficient hole-injecting material such as HAT-CN. Another desirable formulation of a CGL has an undoped ETL layer, a layer of Li or Ca, an interlayer of the same or different electron-transporting material and an electron-deficient hole-injecting material, or a hole-transporting material doped with a p-dopant.

[0129] Suitable electron transport materials, hole injection or transport materials, and n-dopants, p-dopants suitable for use in CGLs are well known and commonly used. The materials may be organic or inorganic. The selection of the appropriate material is not critical and any may be selected based on its performance. The thickness of the CGL should desirably be in the range of 200-450 Å, but may be in the range of 100-200 Å in some cases with thinner CGLs. Often, the CGL will have an ETL or HBL on the anode side and an HTL or EBL on the cathode side to improve charge transport and to help separate the charge generating dopant (if present) from the LEL in the light emitting unit. There may be multiple such layers, and they may be doped or undoped as desired.

[0130] Disposed on top of the CGL (layer 506) is a second light-emitting layer or unit (LEL2, layer 507), which represents the second stack of the OLED device. In FIG. 10, the two LELs (layers 504 and 507) are separated by the CGL (layer 506), and thus the OLED stack of FIG. 10 is a "two-stack" (or double-stack) OLED. There may be one or more HTLs (doped or undoped) between the CGL (layer 506) and LEL2 (layer 507). LEL2 can emit the same color as LEL1 or a different color.

[0131] At least one HBL (layer 508), similar to that described as layer 505, is disposed above LEL2 (layer 507).

[0132] Above the HBL (layer 508) is disposed an electron transport layer (ETL, layer 509). The purpose of the ETL is to manage the transport of electrons from the EIL to the emissive layer below. Suitable electron transport materials are well known and commonly used. These layers may be mixtures of such materials and may include dopants to modify their properties. They are non-emissive and therefore do not include emissive materials. There may be multiple ETLs. The selection of the appropriate material is not critical and any may be selected based on its performance. One example of a suitable ETL is TPBI.

[0133] Above the ETL (layer 509) is an optional electron injection layer (EIL, layer 510). The purpose of the EIL is to manage the transport of electrons from the cathode to the organic layers. Suitable electron injection materials are well known and commonly used. These layers may be mixtures of such materials and may contain dopants to modify their properties. They are non-emissive and therefore do not contain any emissive material. Generally there is only one EIL. The selection of the appropriate material is not critical and any may be selected based on its performance. One example of a suitable EIL material is LiF.

[0134] Above the light-emitting organic layers (50, layers 501-510 in FIG. 10) is a top electrode 60, which in FIG. 10 is the cathode. The top electrode 60 is preferably composed of a thick layer of a metal or metal alloy, such as Al, Ag, Mg / Al, Mg / Ag, etc. The second electrode can be deposited by any known technique. The second electrode may be patterned in the non-emitting areas, but is typically deposited uniformly on the emitting areas. For an external power source, a contact area (contact pad) is needed outside the encapsulant, which is electrically connected to the top electrode inside the encapsulant. Examples of suitable materials for the top electrode are Al, Al / Mg, Ag / Mg, Ag.

[0135] An optional protective or spacing layer (layer 511 in Figure 10) may be provided over the top electrode to prevent damage during encapsulation. These may be small molecule organic, polymeric or inorganic materials. Organic materials are preferred.

[0136] An encapsulant 70 is deposited or placed over the reflective cathode and any protective layers (if present). At a minimum, the encapsulant should completely cover the light emitting area on the top and sides and is in direct contact with the substrate. The encapsulant should be impermeable to air and water. The encapsulant may be transparent or opaque. The encapsulant should not be electrically conductive. The encapsulant may be formed in situ or added as a separate preformed sheet with provisions for sealing the side edges.

[0137] An example of in situ formation can be thin film encapsulation. Thin film encapsulation involves depositing multiple layers of alternating inorganic materials and polymer layers until a desired degree of protection is achieved. Formulations and methods for forming thin film encapsulation are well known and any may be used as desired.

[0138] Alternatively, sealing may be provided using a preformed sheet or cover slip that is applied over at least the sealing area and the encapsulation area. The preformed sheet may be rigid or flexible. The preformed sheet may be made of glass (including flexible glass), metal, or an organic / inorganic barrier layer. It is desirable for the preformed sheet to have a thermal expansion coefficient close to that of the substrate to achieve a stronger connection. The preformed sealing sheet may need to be applied over the sealing area with an air or water resistant adhesive, such as silicone or epoxy adhesive, or by thermal means, such as ultrasonic welding or glass frit welding, in which case an additional sealant, such as solder or glass frit, may be required. The side and bottom edges of the cover slip may be specially designed to better fit into the sealing area or promote a better seal. The cover slip and sealing area may be designed together to be partially mated or locked before the seal is formed. Additionally, the cover slip may be pretreated to promote better adhesion to the sealing area.

[0139] In some applications, an increased degree of encapsulation is required. This can be achieved by providing an additional metal foil encapsulant (layer 513) that is attached over encapsulant 70 by a pressure sensitive adhesive (layer 512). The use of metal foil not only provides a robust encapsulation, but also acts as a heat sink to prevent excessive heating that would be detrimental to the OLED device.

[0140] In many applications, a single stack OLED device can provide sufficient emission for the intended purpose. Some applications require more brightness than a single OLED stack can provide. In such cases, two or more stacks (as shown in FIG. 10) are required. Generally, adding another OLED stack (i.e., two instead of one) doubles the brightness but also requires twice the power. A three-stack OLED provides three times the brightness but requires three times the power, and so on. In the split OLED device of the present invention, as many stacks as necessary to obtain the desired brightness can be added, the only limitation being the increase in voltage required to drive the device. Desirably, there are at least two stacks in the split OLED device, and there are as many as six stacks.

[0141] Another way to increase the brightness of an OLED, especially if monochromatic emission is desired, is to incorporate the microcavity effect. To create a microcavity, one electrode is made reflective and the other semi-transparent, causing the light to reflect internally. The distance between the two electrodes causes interference, eliminating or reducing some wavelengths of light and enhancing others. The microcavity effect can be used in the OLED segment of an OLED device.

[0142] The various individual LELs or units in a split OLED device are not limited to providing the same color, although some applications require monochromatic emission. For example, many automotive taillight applications require all LELs or units to produce red light. Note that while the different LELs or units may all emit the same color light, they do not all need to have identical emission spectra, and some may have a different percentage of certain wavelengths than others (i.e., one unit produces a spectrum rich in short red wavelengths, while another unit produces many long red wavelengths).

[0143] The presence of the index-reducing material allows the power feed to be placed underneath the split electrodes, making such an arrangement particularly suitable for applications where one OLED segment completely surrounds another OLED segment but is separately controlled, as shown in Figures 11A-11C.

[0144] Figure 11A shows a split OLED device 900 of similar structure to 200 (Figure 2A), but where the larger split electrodes 1, 2, 3, and 4 are further segmented into smaller split electrodes 101, 102, 103, and 104. In 900, 101, 102, 103, and 104 are elliptical in shape and are completely surrounded on all sides by the rectangular split electrodes 1, 2, 3, and 4. All of the split electrodes 101, 102, 103, and 104 are laterally separated from the surrounding split electrodes 1, 2, 3, and 4 by PDL 40 or other insulating material, and thus are not in electrical contact. The split electrodes 101, 102, 103 and 104 are correspondingly controlled by external contact pads 2101, 2102, 2103 and 2104 and power feeds 1101, 1102, 1103 and 1104 with vias (through insulating layer 30) 3101, 3102, 3103 and 3104. Because these segments are entirely contained within other segments, the power feed to the inner segment must pass directly beneath some portion of the active light emitting area of ​​the surrounding segment.

[0145] 11B is an end view of OLED device 900, similar to FIGS. 2B and 3B, taken from the side nearest electrode segments 3 and 4. Compared to OLED device 200, 900 has four additional electrodes that will control interior segments 101, 103, 102, and 104. Power FeedIn this view from an end view, only bottom electrode contact areas 2103, 2101, 2102 and 2104 are directly visible, but the corresponding power feeds 1103, 1101, 1102 and 1104 extend directly behind the contact areas. Vias 3103, 3101, 3102 and 3104 extend from the power feeds through insulating layer 30 to split electrodes 103, 101, 102 and 104. A pixel defining layer (PDL) 40 is present in the gaps between all the electrode segments, as well as along the outer edges. Above the PDL 40 and electrode segments 1, 2, 3, 4, 101, 102, 103, 104 is an OLED layer 50 for light emission, and a top electrode 60. Along one edge there is an extension of the top electrode 60 to the edge of the substrate 10 to form a contact area 260. Overlying top electrode 60 is encapsulant 70 , exposing bottom electrode contact areas 21 , 23 , 24 , 22 , 2101 , 2103 , 2104 , 2102 and top electrode contact area 260 .

[0146] 11C shows a cross section of OLED device 900 viewed from the left along the line indicated. In this view, the long power feed 1102 obscures the shorter power feeds 1104, 14, and 12. However, the additional power feeds 1102 and 12 (obscured in this view) are longer and appear to extend all the way to the corresponding split electrodes 101 and 102 (just behind 101).

[0147] The split OLED device 900 has a common organic layer for light emission 50 across all electrode segments. This results in the same emission from all OLED segments, even though the interior segments are controlled separately from the surrounding segments. This design allows great flexibility for controlling the patterns the device produces.

[0148] However, in some applications, it may be desirable for all or some of the interior segments of the array to emit light of a different color than the surrounding segments. For example, in the design of an automobile taillight, it may be desirable to have the interior segments emit W, Y, amber, or orange, and the surrounding segments emit R. In this case, the organic layer 50 on each segment must be appropriately patterned. In such a design, the organic layer for each differently emitting segment must be laterally separated from the adjacent segments. The top electrode may be common to all segments. See 800 in FIG. 9 for an example of a device with differently emitting segments. Alternatively, the OLED segments may produce W or multimodal emission, with the different emissions produced by the use of color filters.

[0149] 12A shows a top view of a split OLED device with a layout that includes an array of OLED segments where an individual OLED segment (oval shaped) is partially completely surrounded by another segment (hexagon shaped). In this example, there are 290 segments including ovals, triangles, hexagonal borders around ovals, and 1 / 2 hexagons.

[0150] FIG. 12B (an enlarged view of a section of FIG. 12A) and FIG. 12C (an enlarged view of a section of FIG. 12B) show the split OLED device of FIG. 12A. Power Feed This is a top view of the layout of Figure 12 before adding any top layers. There are 290 power feeds (one for each OLED segment). Figure 12C shows that the power feeds can get wider as they extend towards the top of the light emitting area (away from the external contact area). For larger segments, it is important to have wider bus lines to minimize voltage drop. By making some power feeds less resistive than others, we achieve a similar voltage drop across all segments, regardless of their distance from the power supply or the size of the segment.

[0151] Figure 13 shows Power Feed Figure 1 shows a top view of a bottom-emitting split OLED device with an index-reducing layer positioned below the electrode segments and in the emitting light path. As in Figure 1 without the index-reducing layer, the OLED segments are arranged in an array of triangles and hexagons with non-emitting gaps between them. The underlying power feed is made of ITO formed on the index-reducing layer and separated from the top electrode segments by a polymeric insulating layer. Unlike the prior art device shown in Figure 1, the power feed is completely invisible.

[0152] In some applications, a portion of the top surface of at least some of the split electrodes may be patterned with an insulating material. This may be used to create permanently dark (non-emissive) designs that are visible whenever the OLED segments are emitting light. This may be used to add designs such as stripes, dots, images, logos, etc.

[0153] One method for fabricating a split OLED device (such as 200) having an array of OLED segments with reduced visibility of the power feed disposed in the emitted light path may include, in order, the following steps. 1) depositing a layer of a non-electrically conductive refractive index reducing material onto a transparent substrate; 2) patterning a conductive power feed directly over and in contact with the index reduction such that there is one power feed for each OLED segment; 3) depositing an electrically non-conductive insulating layer over the power feeds and over the lateral spaces between the power feeds; 4) forming a via in the insulating layer above the power feed to expose a top surface of the power feed; 5) filling the vias with a conductive material; 6) patterning bottom electrode segments onto the insulating layer and making electrical contact with the power feeds through the filled vias; 7) depositing a light-emitting organic layer over the electrode segments; 8) depositing a top electrode over the organic layer; 9) Form an encapsulant over the top electrode.

[0154] Another method (such as 300) for fabricating a split OLED device having an array of OLED segments with reduced visibility of the power feed located in the emitted light path may include, in order, the following steps. 1) depositing conductive power feeds onto a transparent substrate such that there is one power feed for each OLED segment; 2) At least Power Feed Between and Power Feed A refractive index reducing material is deposited at a position where the material is in direct contact with the 3) depositing a non-electrically conductive insulating layer over the refractive index-reducing material and the power feed; 4) forming a via in an insulating layer over the power feed to expose a top surface of the power feed; 5) filling the vias with a conductive material; 6) patterning bottom electrode segments onto the insulating layer and making electrical contact with the power feeds through the filled vias; 7) depositing a light-emitting organic layer over the electrode segments; 8) depositing a top electrode over the organic layer; 9) Form an encapsulant over the top electrode.

[0155] Some useful variations on both of these methods include the following. - If the power feeds are patterned directly on the transparent substrate and then the index-reducing material is deposited at least between the power feeds, the index-reducing material can also cover the top surface of the power feeds. In this embodiment, the insulating layer is optional. - The step of patterning the electrode segments comprises forming an electrically non-conductive pixel-defining layer between the segments. - Filling of the vias and patterning of the electrode segments are done in the same step. - the reflectance difference (D) between the area of ​​the transparent substrate where there is a power feed and the area of ​​the transparent substrate where there is a gap between the power feeds R The materials for the power feed and the refractive index reducing material are selected so that the refractive index is 5% or less, preferably 1% or less. - Power Feed RI and R of the refractive index reducing material I Ratio (High R I / low R I ) is in the range of 1.00 to 1.06, or preferably in the range of 1.00 to 1.03.

[0156] Some favorable physical and performance characteristics of a split OLED device with an index-lowering layer include the following: Brightness: 2,000~20,000Cd / m, Number of OLED segments: 200 or more (can be of mixed sizes and shapes), Active area: 25cm 2 That's all, Segment size: <5mm 2 , 2000cd / m 2 Current density: 13mA / cm 2 (2 stacks), 4.3mA / cm 2 (6 stacks), 5000cd / m 2 Current density: 32mA / cm 2 (2 stacks), 9mA / cm 2 (6 stacks), 10000cd / m 2 Current density: 25mA / cm 2 (6 stacks), 20000cd / m 2 Current density: 50mA / cm 2 (6 stacks), Non-emitting gap: <1mm, preferably <700μm, most preferably <200μm; All electrical contact areas outside the encapsulant (bottom and top electrodes) are located on only one edge of the device.

[0157] The above description describes a number of different embodiments, and individual features from any of the embodiments can be combined without restriction.

[0158] In the above description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration specific embodiments that may be practiced. These embodiments have been described in detail to enable one skilled in the art to practice the invention, and it should be understood that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the scope of the invention. Thus, the description of any exemplary embodiment should not be construed in a limiting sense. While the invention has been described for purposes of illustration, it should be understood that such details are for that purpose only and that modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. [Explanation of symbols]

[0159] 1, 2, 3, 4 bottom split electrode, 11 power feed for split electrode, 21 external contact area for power feed 11, 31 via from power feed 11 to split electrode 1, 2, 12, 22, 32 split electrode, power feed, contact area, via, 3, 13, 23, 33 split electrode, power feed, contact area, via, 4, 14, 24, 34 split electrode, power feed, contact area, via, 10 common transparent substrate, 20 common index matching or high index layer, 30 insulating layer, 40 pixel defining layer between split electrodes, 50 organic layer for light emission, 50A, 50B, 50C, 50D split organic layer for light emission, 60 top electrode, 260 external contact area for top electrode, 70 encapsulant, 75 light emitting area, 80 non-light emitting gap between OLED segments, 85 gap between power feeds, 101 enclosed split bottom electrode, 1101 Power feed for bottom electrode 101, 2101 External contact area for power feed 1101, 3101 Via from power feed 1101 to split electrode 101, 102, 1102, 2102, 3102 Split electrode power feed, contact area, via, 103, 1103, 2103, 3103 Split electrode power feed, contact area, via, 104, 1104, 2104, 3104 Split electrode power feed, contact area, via, 100-900 Split OLED device, 1000 OLED device, 501 HIL, 502 HTL, 503 EBL, 504 LEL1, 505 HBL, 506 CGL, 507 LEL2, 508 HBL, 509 ETL, 510 EIL, 511 Optional protective layer, 512 Pressure sensitive adhesive, 513 Metal foil encapsulant / heat sink.

Claims

1. An OLED device comprising an array of bottom-emitting OLED segments disposed on a common transparent substrate (10), the individual OLED segments being separated by non-emitting gaps (40, 80); The OLED segments are defined by transparent bottom electrode segments (1, 2, 3, 4), the bottom electrode segments (1, 2, 3, 4) are electrically connected to and controlled by individual power feeds (11, 12, 13, 14), and at least some of the power feeds (11, 12, 13, 14) are disposed between the bottom electrode segments (1, 2, 3, 4) and the transparent substrate (10) in an emitted light path (75) such that they are not electrically connected to any other of the bottom electrode segments (1, 2, 3, 4) other than the bottom electrode segments (1, 2, 3, 4) that they control; at least one refractive index reducing material (20) disposed between said bottom electrode segments (1, 2, 3, 4) and said transparent substrate (10); the ratio of the refractive index of the material of the power feed (11, 12, 13, 14) to the refractive index of the refractive index reducer (20) is 1.00 to 1.06; The refractive index reducing material (20) is in direct contact with at least one surface of the power feed (11, 12, 13, 14); an OLED device, wherein the refractive index reducing material (20) is disposed between the lower surfaces of the bottom electrode segments (1, 2, 3, 4) and the upper surfaces of the power feeds (11, 12, 13, 14), and / or between the lower surfaces of the power feeds (11, 12, 13, 14) and the upper surface of the transparent substrate (10), and / or in the lateral spaces (85) separating the individual power feeds.

2. 2. The OLED device of claim 1, wherein the refractive index reducing material (20) is a continuous layer disposed between the lower surface of the bottom electrode segment (1, 2, 3, 4) and the upper surface of the power feed (11, 12, 13, 14).

3. 3. The OLED device of claim 2, wherein the index-reducing material (20) is additionally disposed in lateral spaces (85) separating the individual power feeds.

4. 4. The OLED device of claim 2, further comprising an additional insulating layer (30) disposed between the upper surface of the power feed (11, 12, 13, 14) and the lower surface of the bottom electrode segment (1, 2, 3, 4).

5. 5. The OLED device of claim 4, wherein the insulating layer (30) is disposed between the index-reducing material (20) and the lower surface of the bottom electrode segment (1, 2, 3, 4).

6. The reflectance difference (D) between the area of ​​the transparent substrate (10) where the power feeds are arranged and the area of ​​the transparent substrate (10) where the gaps (85) between the power feeds are arranged Ｒ 3. The OLED device of claim 1 or 2, wherein the OLED display has a luminance of 0.1 to 0.5 nm.

7. 7. The OLED device of claim 6, wherein the index-reducing material (20) comprises two or more inorganic materials with different refractive indices.

8. The power feeds (11, 12, 13, 14) are made of conductive metal oxides, and the refractive index reducing material (20) is Nb ２ O ５ and SiO ２ 8. The OELD device of claim 7, wherein the OELD device is a mixture of

9. 8. The OLED device of claim 7, wherein the power feeds (11, 12, 13, 14) are formed from a conductive metal oxide and the refractive index reducing material (20) is a mixture of inorganic nanoparticles suspended in a polymer matrix comprising a polymeric siloxane with high molecular weight organic functional groups.

10. 10. The OLED device of claim 1, wherein all of the OLED segments in the array emit light of the same color.

11. 10. The OLED device of claim 1, wherein some of the OLED segments emit light of a different color than other segments.

12. 10. The OLED device of claim 1 wherein at least one of the OLED segments in the array is disposed within and entirely surrounded by another OLED segment.

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