Segmented OLED with patterned buslines

Abstract

An OLED device comprising an array of bottom -emitting OLED segments, each with a bottom electrode segment, a top electrode and organic layers for light emission, separated by a non-emitting gap. Each segmented bottom electrode has an individual power feed which can be opaque. At least one individual power feed for another OLED segment is arranged within the emission light path of a first OLED segment. The power feeds located within the emission light path are part of a visible pattern of evenly spaced parallel lines of constant width. The visible pattern can include a non-electrically connected extension line associated with each power feed which together form a visibly continuous extended line. The visible pattern can include extra pattern lines. Visible regular patterns appear to be less noticeable or apparent by the human visual system.

Description

[0001] Title

[0002] SEGMENTED OLED WITH PATTERNED BUSLINES

[0003] Cross Reference to Related Applications

[0004] Reference is made to co-assigned PCT application PCT / US2022 / 029413 entitled “SEGMENTED OLED WITH ELECTROSTATIC DISCHARGE PROTECTION” filed 16 May 2022 and co-assigned PCT application PCT / US2022 / 029409 entitled “SEGMENTED OLED” which claims the benefit of U.S. Provisional Application No 63 / 192,942 filed May 25, 2021.

[0005] Background

[0006] LED and OLED lighting panels offer many advantages for general lighting purposes. They are efficient in terms of light output for power consumed. They are low voltage which helps avoid potential electrical shocks, less prone to sparking in potentially explosive environments and reduce loads in the supporting electrical system. The spectrum of emitted light can be varied using appropriate internal designs. They produce little or no UV or IR light. They are instant on; that is, they emit light immediately whenever electrical power is supplied.

[0007] LED light sources are inherently small point sources and in order to serve as a flat general lighting source, many separate LED devices must be ganged together. This raises manufacturing costs and complexity. Uniformity of the light surface must be controlled by appropriate design. LEDs produce some heat and so, heat sinks or other thermal control measures are often employed. Practical LED lighting panels can be made very thin, for example as thin as 3-16 mm, with appropriate system design.

[0008] OLED light sources are inherently flat area light sources. They offer several advantages over LED lighting panels. They can be made even thinner (for example, less than 1 mm thick) and they produce very little heat under normal operating conditions. However, OLED lifetimes can be an issue. Both LED and OLED lighting panels can be made on flexible or curved substrates even though OLED is preferred for these types of applications.

[0009] In summary, both LED and OLED devices can be useful as lighting panels. They are both efficient, low voltage, cool to the touch, and are thin.

[0010] For some applications, multiple independently controlled individual OLED or LED devices can be mounted on a separate single substrate to provide a ‘tiled’ device. In this application, each independent OLED or LED light source is previously and independently manufactured in its entirely (except for electrical connections) including its own substrate and mounted side-by-side or in an array. Such devices can provide either variable general lighting (i.e., by supplying power to the individual units according to desired amount of overall light) or a low-resolution communication device (i.e., by supplying power to the individual units in a pattern). OLED panels are often advantaged for this usage since the OLED can have a larger emission area than an individual LED. This provides a larger fill factor (total area of light emission) which is often desirable. In order to provide a larger emission area with LED light sources, it is necessary to use multiple LEDs, all sharing the same power source, within the same area. This increases manufacturing complexity and cost and does not provide a uniform appearance without the use of diffusers (which decrease efficiency of light output and decrease sharpness and contrast at the edges of the emission area).

[0011] For other applications, multiple independently controlled individual OLED devices can be manufactured directly on a single common substrate to provide a ‘segmented’ OLED device. There are non-emitting gaps or spaces between the individual segments. The surface area comprising the individual segments corresponds to the lighting area and is typically surrounded by a non-lighting border area along the outside edges of the substrate. Such segmented OLED light sources can offer manufacturing and cost advantages because many layers can be shared across all the individual units and there is no need to handle or mount the separate OLED panels. Because LEDs must be individually manufactured on their own substrate, it is not possible to make a true segmented LED device where all the LEDs share a common internal substrate. Segmented OLED devices can provide either variable general lighting or a low-resolution communication device.

[0012] Segmented OLED devices are particularly suitable for automobile exterior lighting applications (e.g., tail-lights) since they, unlike LED devices, require no additional reflectors, light guides, or additional optics to generate homogeneous surface light. For example, see M. Kruppa et a Information Display 4 / 19, p. 14-18 (2019). Moreover, applications such as automobile tail-lights often require some degree of visibility from the side as well as directly from the rear so the tail-light assembly often has a complex design with a mixture of curved and relatively flat surfaces. Segmented OLED devices can be prepared on flexible substrates which simplifies design considerations in a non-planar tail-light assembly. However, automobile tail-light assemblies are an integral part of the overall exterior appearance of the vehicle and must provide a sleek and compatible design and appearance.

[0013] In general, 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). In order to create an individually controlled OLED segment, at least one of the electrodes must be divided into segments; that is, the electrode for one OLED segment is electrically separated from a corresponding electrode in a different OLED segment. In this way, the emission from each of the OLED segments can be individually controlled by a single unique electrical power feed to the electrode segment.

[0014] Although both top-emitting and bottom-emitting OLEDs are suitable for automobile applications, bottom-emitting OLED are preferred for at least two reasons. First, robust encapsulation is necessary for exterior applications. This is more difficult to achieve with transparent encapsulation, which is required for a top-emitting OLED, particularly when the OLED (and thus the encapsulation) must be flexible. A bottom-emitting OLED can use very robust encapsulation since the encapsulation on the non-emitting side does not need to be transparent. Second, the OLED will be located in a confined space where heat build-up can be problematic. A bottom-emitting OLED allows for a heat sink to be located on the back side. With a top-emitting OLED, the heat sink is located on the opposite side of the substrate which reduces the rate of heat transfer and so, cooling is not as efficient.

[0015] The need to have a separate electrical power feed (also referred to as power line, bus line (busline), metal trace, conductive trace, lead or current trace) for each segment in a segmented OLED device creates a number of design issues. If the power feeds are located under the active area of the OLED segment in the emission pathway, they can be visible because of light absorbance or light scattering. This is undesirable. In particular, locating the power feeds directly on a transparent substrate under the transparent bottom electrode or above the transparent bottom electrode and below the organic layers in a bottom-emitting OLED can both be problematic. Moreover, depending on their reflectivity, they might be visible even when the segment is off and not-emitting because of incident light entering the OLED and being reflected off the power feed. The visibility of the power feeds at any time would be detrimental to the sleek and uniform appearance of the segmented OLED device.

[0016] This problem is illustrated in Fig. 1 which is a top-view photograph of a prior art bottom-emitting segmented OLED device where the power feeds are located under the electrode segments and in the emission light path. In this particular example, the individual OLED segments are arranged in an array of triangles and hexagons with non-light emitting gaps between them. The underlying individual power feeds are made of ITO and run directly under the OLED segment and in the emission light pathway. The power feeds are separated from each other laterally as well as separated from the overlying electrode segments by an insulating layer of SiO2. In this arrangement, the ITO power feeds, which are non-linear nor evenly spaced, are clearly visible, even though being partially transparent, and the entire segmented OLED device does not have a sleek and clean appearance. The segmented OLED device of Fig.1 is shown in an unlit, non-emissive state. The ITO powers feeds are visible because ambient light can pass through the transparent substrate, the partially transparent power feeds, the partially transparent bottom electrode (also made of ITO) and bounce off the reflective top electrode and back though the other structures and substrate. Because part of the light is absorbed by the power feeds, they become visible. In an operating emissive (lit) state, the power feeds may or may not be visible, depending on the emission level and viewing distance. In either situation, visible power feeds are undesirable, although the relative importance will depend on the specific application.

[0017] The electrical power feeds can be generally made of conductive materials and must be conductive enough to supply the power over a distance, which can be in some instances relatively long (for example, interior segments), without significant IR (current x resistance or voltage) drop due to resistance. This can result in uneven luminance. Generally speaking, 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 mostly transparent, the required thickness and width necessary to provide sufficient conductance can cause the power feed to become visible. If they are thin enough to be almost invisible, then the amount of power loss due to IR drop may be unacceptably large. In order to avoid IR drop, power feeds made of highly conductive metal would be desirable; however, metal power feeds generally would be need to be thick enough to be totally opaque to light, although in some instances, they may be semi-opaque and partially transmissive to light. In either case, metal power feeds would be visible if located in the emission pathway. It is important that the IR drop along the power feeds be similar for all OLED segments without regard to the distance from the external power source or the size of the OLED segment (larger segments require more power for operation than smaller segments). However, IR drop can be minimized by adjusting the width (parallel to the substrate) or height (above the substrate) of the power feed.

[0018] For this reason, it would be desirable for the electrical power feeds to be located in the non-emitting gaps between the individual OLED segments so the power feeds are not visible, at least when the OLED segments device are emitting when the gaps will appear dark. Typically, the non-emitting gaps between the individual OLED segments will be consistent in width to provide a uniform appearance and will be as thin as possible in order to maximize the emission area. However, locating the power feeds in the non-emitting gaps between OLED segments can be problematic. First, all power feeds (one per individual OLED segment) must be separate and electrically isolated from each other so that each segment can be independently controlled and there are no short circuits. Depending on the arrangement of the OLED segments and the width of the gaps, it may not be possible to place all of the necessary power feeds in the limited area of the non-emitting gap without have to cross one feed over another feed without contact between them. This would greatly increase manufacturing costs. Second, the power feeds for OLED segments along or close to the edges of the device are relatively short while the power feeds to those OLED segments in the interior of the device are relatively long, particularly if the path of the power feed is convoluted because it is restricted to the gaps between the segments. Assuming a common power source, the power delivered by a longer power feed may be less than that delivered by a shorter power feed due to its increased resistance (IR drop). This can result in uneven emission where the interior segments have lower emission than those along the edges of the device. For this reason, the power feeds to the interior OLED segments may need to be larger in size (to reduce resistance) and the gap may not be wide enough to allow for multiple larger power feeds. For these reasons, it is often impractical to locate all of the power feeds in the gaps between the OLED segments.

[0019] To avoid these issues, many previous approaches to segmented OLED devices are based on top-emitting OLED formulations where the electrical power feeds are not visible. However, it would still be desirable to arrange the power feeds on the substrate in a segmented bottom-emitting OLED device so that any power feeds located within the emission pathway of the individual OLED segments are not visible, or at least, less apparent or noticeable.

[0020] Commonly assigned WO2022 / 250995 describes a segmented OLED device wherein the segment power feeds are arranged within the emission light path. The visibility of the power feeds is reduced by including at least one refraction-reducing material in contact with the power feed. However, this approach is not suitable for metal power feeds which are opaque and located in the emission pathway.

[0021] Commonly assigned WO2023 / 224594 describes a segmented OLED device with an internal passive capacitor structure. The power feeds to the segments can be arranged within the emission light path.

[0022] Bechert et a “Flexible and highly segmented OLED for automobile applications”, Proc. Of SPIE, Vol. 10687, SPIE Photonics Conference Europe, 2018 describes a top- emitting OLED where the bottom electrode of each segment is electrically connected to metal traces located on the substrate by vias through a polymeric insulating layer that separates the two.

[0023] US9048450B2 describes the use of current distribution lines that contact the interior of a 1st electrode and are located over the 2nd electrode and not in the emission pathway.

[0024] US20140326983A1 describes an OLED where bus lines are located over or in between the anode segments. They are not located between the anode segment and the substrate. US 9,583,731 relates to an auxiliary electrode which is located in grooves that are outside the light path.

[0025] Other references that describe power feeds in bottom-emitting segmented OLEDs include US8309977B2, US8432095B2, US10888002B2, US8927309B2, US8653509, US2017 / 0207411, US9692005, US10141535, US8941143, US9487878, US9159945, US7408296, US10068958, US9627643, US2006 / 0108915, US7336036, JP2002075662 and US20190363155.

[0026] It is known that internal structures arranged in a periodic pattern can improve light scattering or reduce surface plasmon formation in OLEDs. Examples include: US10581029B2; DE102011076733A1; JP2017162616A; US8541778; US20120132897; US8710527B2; and US9203054B2. However, these structures are not electrically conductive nor act as power feeds.

[0027] Some other reference articles include: A. Salehi et al, “Recent Advances in OLED Optical Design”, Adv. Funct. Mater., 29, 1808803 (2019); “Human Eye Contrast Sensitivity to Vehicle Displays under Strong Ambient Light”, Y. Qian et al, Crystals, 13, page 1384 (2023); “Spatial Luminance Contrast Sensitivity: Effects of Surround”, Y.J. Kim and H-s. Kim, Journal of the Optical Society of Korea, 14 (2), pp. 152-162 (2010); “14.4: Contrast Requirements for OLEDs and LCDs Based on Human Eye Glare”, E. Langendijk and M. Hammer, SID Symposium Digest, 41 (1), pp 192-194 (2010); “An Effective Quantification Method for Evaluating Horizontal Line Defects by Interference between Flexible OLED and Touch Sensor”, J.Ko et al, SID Symposium Digest, 52 (1), pp 1346-1349 (2021); and F.C. Huang et al, “Correcting for Optical Aberrations using Multilayer Displays”, ACM Transactions on Graphics, Vol. 31 (6), Article 185 (2012)

[0028] Summary of Important Features

[0029] In order to reduce the noticeability of opaque power feeds that are located in the pathway of light emission, it is very desirable that power feeds within the emission pathway are arranged as part of a visible pattern of evenly spaced parallel lines of constant width that appear to continuously extend across the active areas from one OLED segment to another within the array. Such a regular pattern is less noticeable or visibly apparent than a broken or irregular pattern.

[0030] Some of the important features include an OLED device comprising an array of bottom-emitting OLED segments arranged on a common transparent substrate, each individual OLED segment being separated by a non-emitting gap; wherein each OLED segment has an active area defined by a transparent bottom electrode segment, a top electrode and organic layers for light emission between the top electrode and bottom electrode segment, where each segmented bottom electrode is electrically connected to an individual power feed; so that for at least a first OLED segment (SI), there is at least one individual power feed for another OLED segment, which is not in electrical contact with the first OLED segment (SI), arranged within the emission light path of the first OLED segment (SI); wherein the power feed for another OLED segment located within the emission light path of the first OLED segment (SI) is included as at least part of a visible pattern of evenly spaced parallel lines (50, 51) of constant width that appear to continuously extend across the active areas of the first (SI) and at least one other OLED segment.

[0031] The above OLED device wherein at least one of the parallel lines of the visible pattern includes a first line section which is an individual power feed and a second line section that is an extension line, which is electrically isolated from the power feed in the first line section, so that the first- and second-line sections together form a straight line that visibly appears to be continuous.

[0032] Any of the above OLED devices wherein at least part of the visible pattern includes at least one extra pattern line which is separate from and electrically isolated from any of the individual power feeds.

[0033] Any of the above OLED devices wherein the extension line (50a, 56, 58, 60a, 62a) of the visible pattern is located in the same plane above the substrate as the power feed (Pl, P2, P3,. . .), has the same composition as the power feed (Pl, P2, P3,. . .), and has the same width as the power feed (Pl, P2, P3,...).

[0034] Any of the above OLED devices wherein all of the individual power feeds and extra pattern lines within the array are opaque to light. The individual power feeds may comprise layers of chromium and aluminum.

[0035] Any of the above OLED devices where at least two of the lines of the visible pattern extend from one edge of the light-emitting area of the array to the opposite edge so that the lines of the pattern are visible in the emission of all OLED segments along that line. Any of the above OLED devices where there are two or more overlapping visible patterns of evenly spaced parallel lines of constant width, wherein the evenly spaced parallel lines of each pattern are set at an angle to each other.

[0036] Any of the above OLED devices wherein the visible pattern of evenly spaced parallel lines of constant width is superimposed over at least 70% of the total emitting area of the array. There can be one primary visible pattern of evenly spaced parallel lines of constant width and one or more secondary visible patterns, wherein the primary pattern is superimposed over at least 51% of the total emitting area of the array. The primary pattern can be located in the center of the array and all of the secondary pattern(s) are located within 20% of the total distance of the light-emitting area of the array to the nearest edge.

[0037] Any of the above OLED devices where there are power feeds for at least one OLED segment located within the non-emitting gap. At least one of the parallel lines (50, 51) of the visible pattern can be located within the non-emitting gap, the line within the non-emitting gap includes a first line section which is an individual power feed and a second line section that is an extension line, which is electrically isolated from the power feed in the first line section, so that the first and second sections together form a straight line that visibly appears to be continuous.

[0038] Any of the above OLED devices where the parallel lines are spaced apart by a distance (d) in a range of 0.05-10 mm. Any of the above OLED devices where the width of the parallel lines is in the range of 0.005-1 mm.

[0039] Brief Description of the Drawings

[0040] Fig. l is a top-view photograph of a prior art bottom-emitting segmented OLED device where the power feeds to the individual OLED segments, which are located below the electrode segment and in the light path of emission, are visible.

[0041] Fig. 2A is a top-view of a prior art segmented OLED device 100 in a non-operating, unlit state. Fig 2B shows the same view of 100 in an emitting, lit state. Fig. 2C shows the cross-sectional view along Edge 1 (as indicated in Figs. 2A and 2B).

[0042] Fig. 3 A shows a view of an inventive segmented OLED device 200 in an unlit state. Fig. 3B shows the same view of 200 when lit. Fig. 3C shows the cross-sectional view along the line x-y of 200 as indicated in Fig. 3 A. Fig. 3D shows the cross-sectional view along the line x’-y’ of 200 as indicated in Fig. 2A.

[0043] Figs. 4A (unlit) and 4B (lit) shows a top-view of an inventive segmented OLED device 300, Figs. 5A (unlit) and 5B (lit) shows a top-view of an inventive segmented OLED device 400.

[0044] Figs. 6A (unlit) and 6B (lit) shows a top-view of an inventive segmented OLED device 500.

[0045] Fig. 7 shows a partial top-view of a section of an OLED array (unlit) from the emissive side.

[0046] Figs. 8A (unlit) and 8B (lit) shows a view of an inventive segmented OLED device 600.

[0047] Figs. 9A (unlit) and 9B (lit) shows a top-view of the emissive bottom side of an inventive segmented OLED device 700.

[0048] Figs. 10A (unlit) and 10B (lit) shows a top-view of an inventive segmented OLED device 800.

[0049] Figs. 11 A (unlit) and 1 IB (lit) shows a top-view of an inventive segmented OLED device 900. Fig. 11C shows the cross-sectional view along Edge 1 (indicated in Fig. 11 A) of 900 (unlit). Fig. 1 ID shows the cross-sectional view along Edge 2 (indicated in Fig. 11 A) of 900 (unlit).

[0050] Fig. 12A illustrates the Poggendorff Illusion. Fig, 12B illustrates a potential adjustment to avoid the Poggendorff Illusion effect.

[0051] Fig. 13 shows a cross-sectional schematic for a two stack OLED formulation 1000.

[0052] The Figures are illustrative and not to scale. All of the top-views of the devices are all from the (bottom) emissive side of the device (i.e., the transparent support side). All cross- sectional views are drawn with the transparent substrate on the bottom side of the view instead of the top side (which would be consistent with the top-view orientation). This does not in any way change the relationship of the internal structures or any details in the description.

[0053] Detailed Description

[0054] For the purposes of this disclosure, the terms “over” or “above” mean that the structure involved is located above another structure, that is, on the side opposite from the substrate. “Uppermost” or “upper” refers to a side or surface furthest from the substrate while “bottommost” or “bottom” refers to the side or surface closest to the substrate. Unless otherwise noted, “over” should be interpreted as either that the two structures may be in direct contact or there may be intermediate layers between them. By “layer”, it should be understood that a layer has two sides or surfaces (an uppermost and bottommost) and that multiple layers could be present and is not limited to a single layer. “LEL” always refers to a single light-emitting layer. “Unit” generally indicates a minimum of one layer that can be considered to act as one single source of light; a unit may be equivalent to a single LEL, may contain one LEL associated with other non-emitting layers, or may have multiple LELs with or without additional layers. A light-emitting unit is a grouping of one or more LELs that are separated from another light-emitting unit by a charge-generating layer (CGL). Thus, if an OLED device does not have a CGL, there are no light-emitting units, even though it may have multiple LELs. Such a device is often referred to as a “one-stack” device. If an OLED device has two light-emitting units, separated by a CGL, then it can be referred to as a “two- stack” device. A stacked OLED may have multiple units or combinations of units and LELs, that together make up the total emission.

[0055] R indicates a layer or unit that primarily emits red light (> 600 nm, desirably in the range of 620-660 nm), G indicates that a layer or unit primarily emits green light (500-600 nm, desirably in the range of 540- 565 nm) and B indicates a layer or unit that primarily emits blue light (<500 nm, desirably in the range of 440-485 nm). It is important to note that R, G and B layers can produce some degree of light outside the indicated range, but the amount is always less than the primary color. Y (yellow) indicates that a layer or unit that emits significant amounts of both R and G light with a much lesser amount of B light. Unless otherwise noted, wavelengths are expressed in vacuum values and not in-situ values.

[0056] The OLED light-emitting element of the invention can be a single LEL, a single-stack OLED, a two-stack OLED, or even three or more OLED stacks, which can emit a single color or multiple colors. If a single-color light output is desired or the color temperature of the light output needs to be adjusted or modified, color filters may be used to eliminate any unwanted wavelengths.

[0057] An OLED light-emitting LEL or unit can produce a single “color” of light (i.e., R, G, B, combination colors of 2 primary colors, such as Y or cyan, or W (white)). The individual OLED light-emitting units may have a single light-emissive layer or may have more than one light-emitting layer (either directly adjacent to each other or separated from each other by an interlayer). The individual light-emitting units may also contain various kinds of non-emitting layers such as hole transporting layers, electron-transporting layers, blocking layers and others known in the art to provide desirable effects such as promoting emission and managing charge transfer across the light-emitting unit. The single color of light may be generated within the 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 fall within the same color. The single color provided by the OLED unit can be a combination of two primary colors; in particular, a yellow light-emitting OLED unit that produces a combination of R and G light. In this case, yellow counts as a single color.

[0058] A stacked OLED device can produce a single color of light or more than one color of light (multimodal). For example, a multimodal OLED produces a white light with roughly equal amounts of R, G and B light. Typically, this would correspond to CIEX, CZEyvalues of approximately 0.33, 0.33. White light, even if does not contain equal amount of R, G, B light, can generally be produced in OLEDs by having three separate R, G and B light-emitting layers, two separate light emitting layers such as blue and yellow, or even a single white light-emitting layer. A red light-emitting OLED would have CIEX, CZEyvalues of approximately 0.6-0.7, 0.2-0.35. The OLEDs of the invention can utilize a microcavity effect to increase the emission of a desired color of light.

[0059] For specific applications such as automobile taillights which are used to signal braking, stopping, turning and other functions, the light-output of the OLED used should be chosen to meet all government regulations and SAE or industry standards that apply to that use, particularly in terms of color and luminance. In addition, the size and dimensions of the segmented OLED device should be chosen to conform to all appropriate government regulations and industry standards that apply to the particular use. For such applications, the preferred emission color is red.

[0060] The segmented OLED device, which is comprised of multiple individual OLED segments on a common substrate, may have any shape as desired. By “common”, it is meant that all OLED segments in the array share the same substrate and are manufactured together on that substrate as an array. It may be entirely flat or planar, may have multiple planar surfaces angled to each other, may be entirely curved, or may have a mixture of flat, angled or curved surfaces. Typically, the OLED array will have an active (total) emissive area, defined by the outside edge of the area containing the individual OLED segments and not counting the non-emitting gaps between the segments, surrounded by a non-emissive border or edge area. The segmented OLED devices will often be mounted in a housing or part of a module, along with any necessary external power connections and control elements that supply a signal or power to the individual segments. The housing or module will typically have transparent sections that allow the light for the OLED device to pass out and yet provide protection from the outside environment. The housing or module might also have internal reflectors or light guides to help direct light emission as desired. The entire housing or module containing the segmented OLED device can be hermetically sealed. The size of a segmented OLED device suitable for automotive taillight applications is typically in the range of 10 to 500 cm2.

[0061] In a segmented OLED device, each individual OLED segment should have uniform light emission across the active area of the segment, not be subdivided, and be powered by a single source and signal. A segmented OLED device with individually controlled segments arranged in an array can be used for lighting purposes where all segments are activated at the same time to provide uniform light emission (except for the gaps between the segments). The light emission across all segments can be constant, dimming as one, brightening as one or flashing on / off. Alternatively, the segmented OLED device can have each segment activated individually and independently in some sort of a pattern. The pattern may involve some segments which are fully on, some at intermediate luminance levels and some that are off. The pattern may be unchanging over some period of time or may be moving, where the individual segments are activated on / off in some type of time-based or location-based sequence. Since segmented OLED devices are not high-resolution displays and are typically meant to be viewed from a substantial distance, the individual OLED segments are substantially larger than the individual pixels in a high-resolution display (which typically have an emission area much less than 0.1 mm2). Desirably, for smaller segmented OLED devices with a total emission area of 500 cm2or less, the individual OLED segments should have an emission area of at least 1 mm2and desirably at least 3 mm2. For larger sized segmented devices with a total emission area of greater than 500 cm2, the individual OLED segments should have an emission area of at least 0.25 cm2, more desirably at least 1.0 cm2;and most desirably, at least 10 cm2.

[0062] The individual OLED segments can be of any shape or area as desired. Generally, in order to minimize the non-emitting space between the individual segments, the segments will form a packed array. Desirably, the array is a regular array so that the spacing between the segments is uniform and provides a sleek appearance. The array can take any overall form in terms of shape and need not be square or rectangular, but also can be circular, oval, triangular, or polygonal. In some designs, some areas of the array are regular with uniform spacing between them and other parts of the array are irregular. For example, in a square array, the outside of the array can have smaller square segments set in a uniform pattern while the interior area has a single larger star shaped segment in the exact center surrounded a large non-emitting area. Likewise, the shape of individual OLED segments within the array are not limited, but can be square, rectangular, circular, oval, triangular, or polygonal or even irregular as desired. Moreover, the OLED segments within the array need not be all the same shape, but may have a mixture of shapes such as, for example, interlocked triangles and hexagons. Preferred are packed arrays with only triangles, only parallelograms or a mixture of triangles and hexagons or triangles and trapezoids. The individual segments may not have all the same area and the array may be composed of a mixture of large and small segments. The individual segments in the array need not emit the same color (although each individual segment will emit a single color) and the segments that emit different colors can be located in a specific pattern within the array.

[0063] Figs. 2A-2C illustrate the problem of using opaque power feeds in the emission light path of an exemplary segmented OLED device 100 according to the prior art. Figs. 2A and 2B are top views (from the emissive side) of 100, which is an array of seven irregular OLED segments SI to S7 of different sizes and relative locations. However, because of the arrangement of OLED segments within the array, it is necessary to run the power feeds to some segments under or over other OLED segments without any electrical contact between the power feed and the overlying or underlying OLED segment.

[0064] Fig. 2C is a cross-sectional view from Edge 1 as indicated in Fig. 2A. On top of a transparent substrate 10 are located power feeds P1-P7, each of which are individually and uniquely electrically connected to segments S1-S7. Power feeds P1-P7 are opaque to light. Between and over the power feeds P1-P7 is an electrical insulating layer 15, which serves to prevent electrical contact between the individual power feeds and provides planarization of the upper surface. Layer 15 is transparent. Over the insulating layer 15 are located the individual OLED bottom electrode segments 20, which are transparent. Electrical contact between the appropriate dedicated power feed and its electrode segment is made through vias (openings) VI- V7 in the insulating layer 15. Between the bottom electrode segments 20 is an insulating layer (pixel definition layer or PDL) 17 so that there is no electrical contact between them. Over the bottom electrode segments 20 is common organic layer (or layers) for light emission 25 and a common reflective upper or top electrode 30. Together, a bottom electrode segment 20 / light emission layer 25 and top electrode 30 form an individual OLED segment, whose emissive area generally corresponds to the bottom electrode segment. Over the top of the OLED segments and outer sides of the OLED array is an encapsulation layer 35. In the view shown in Fig. 2C, only segments SI and S2 are visible along with a non- emissive gap 5 according to insulating layer 17. Although shown here between segments SI and S2, gap 5 can refer to a non-emitting gap between any two adjacent emitting segments. Light emission from LEL 25 is through the transmissive bottom electrode segments 20, the insulating layer 15 and the transparent substrate 10 as indicated by the arrows. The opaque power feeds P4 and P5 lie directly in the emission path from SI and opaque power feeds P6 and P7 lie directly in the emission path from S2. Power feeds Pl and P2 terminate before any emission area (see Fig. 2A) and power feed P3 is located under non-emitting gap 5 according to layer 17 and so, not in the emission path of any of the segments.

[0065] Fig. 2A shows the device 100 in an unlit, non-emitting state. Note that encapsulation 35 is smaller in area than the substrate 10 so that the ends of the power feeds Pl to P7 are uncovered and exposed along Edge 1. This forms a contact area for the power feeds so they can be electrically connected to an external controller / power source. As illustrated, power feed Pl is connected only to OLED segment SI through via VI, P2 is connected only to OLED segment S2 through via V2, etc. That is, every individual power feed is electrically connected to a single OLED segment and no other. In this example, all of the power feeds have the same width which is constant along their length.

[0066] Because the substrate 10, insulating layer 15, bottom electrode segments 20 and LEL 25 are all transparent, ambient light can enter the device, reflect off the reflective top electrode 30 and back out of the device. However, power feeds Pl to P7 are opaque and so will be visible to an observer as indicated by the solid black lines. Power feed P3, located in the gap 5, may or may not be visible depending on whether insulating layer 17 is transparent or not (in this example, 17 is transparent and so, P3 will be visible) However, because the power feed P3 is opaque and represents a significant area percentage of the gap, the overall appearance of the gap may appear darker than the OLED segments under these conditions.

[0067] It is readily seen that the visible pattern of the power feeds in 100 is not uniform in a non-operating state; that is, some of the power feeds are visible in some of the OLED segments (i.e., SI, S2, S3 and S6) but not others (i.e., S4, S5 and S7). The power feeds appear as partial lines in only some parts in the array. Since the human visual system is more prone to recognize irregular patterns such as in 100 compared to regular patterns, the visual appearance of 100 can be interpretated as less slick, smooth and finished.

[0068] Fig. 2B shows the device 100 in a lit, emitting state. This is illustrated herein by rendering the non-emitting areas as dark, since in a lit state such areas will be perceived as dark. Since the gap 5 is non-emitting, it becomes much less noticeable than the emitting segments SI to S7. Thus, power feeds Pl to P3 that lie in non-emitting areas (i.e., gap 5) should not be very visible. At lower levels of emission, power feed P7 will be visible as a line running across S6, power feeds P4 and P5 will be visible as lines running across SI, P6 and P7 will be visible as lines running across S2 and all four power feeds will be seen as lines crossing over S3.

[0069] This is undesirable since the irregular pattern of lines will be very apparent and noticeable. At high levels of emission, the power feeds may or may not be visible in spite of being opaque because of light diffraction and / or viewing distance.

[0070] In the following figures of inventive OLED arrays, the arrays shown are illustrative only and are meant to demonstrate how the presence of power feeds (with or without additional extension lines) can be used to create a visible pattern of evenly spaced parallel lines in either an unlit or lit state. Different array layouts can affect what kind of visible pattern can be created by the presence of the opaque or partially opaque lines in the emission pathway. The visible pattern may be different between the unlit and lit state. The relative importance of the visible pattern in an unlit or lit state will depend on the application. Many options are possible.

[0071] Figs. 3 A-3B illustrate an inventive device 200 where the opaque power feeds are arranged as at least part of a visible pattern of evenly spaced parallel lines of constant width that appear to continuously extend across all of the active areas from one OLED segment to another within the array.

[0072] Fig. 3 A shows inventive device 200 (in an unlit state) which is like 100 in Fig. 2A except for the presence of a pattern of visible pattern lines 50 which creates a regular visible pattern of evenly spaced parallel lines that linearly extend across all OLED segments in the array and which are all separated by the same distance d. In 200, there are two different types of visible pattern lines 50 that are included in the evenly spaced visible pattern. Note that power feeds Pl and P2 supply power to SI and S2 which are located close to the edge of the device so they are not visible and so, not part of the pattern.

[0073] One type of the visible line 50 within the pattern in 200 comprise extension lines 50a extending beyond an associated power line. In the prior art example 100, power feeds P3 to P7 do not extend past the vias V3 to V7 so that the visible lines they create appear incomplete. Extension lines 50a, which have the same width and visible appearance as P3 to P7, are added as a linear extension to the power feeds (which appear as a partial section of a line). The purpose of the extension lines 50a is to create a visual impression of a complete and continuous straight line that extends across the segments without bends, kinks, or curves as part of the uniform pattern of visible lines 50. In some instances, an extension line 50a may be associated with a power line within the gap (for example, see the extension line 50a associated with P3, which lies within gap 5). At least some of the visible lines 50 of the pattern will have two different sections (the power feed and the extension line) and will visibly appear to be continuous although they are not because the space or gap between the power feed and the extension line is too small to be readily visible. Extension lines 50a are electrically isolated from any of the power feeds as well as any of the OLED bottom electrode segments and do not directly control, participate in or supply power for the operation of the OLED segments. The space or gap that electrically isolates the power feed and the extension line is filled with electrical insulating layer 15. This is illustrated in the enlarged view in Fig. 3 A of the area around the connection of P4 to S4 through via V4. P4 ends at the electrical connection to the edge of S4. Extension line 50a, which continues the line of P4 across the remainder of S4 is not connected at all to P4. However, the space or gap between extension line 50a and P4 is large enough to prevent electrical connection but not large enough to be visibly apparent so that 50a appears to be a linear straight-line continuation of P4 across S4. Ideally, extension lines 50a will appear identical to the power feeds and so, will be composed of the same materials, appear to have the same width and height and be located within the emission path. Extension lines 50a are also desirably located laterally in the same plane above the substrate as the power feeds.

[0074] Another type of visible line within the pattern in 200 comprise an extra pattern line 50b which is not associated with nor a linear extension of any power feed. Such extra pattern lines 50b may be necessary to maintain a constant distance d between the visible lines of the pattern if the power feeds are too far apart because of the differing segment sizes.

[0075] There may be any number of extra pattern lines 50b. The visibility of the extra pattern lines 50b should appear to be the same as the other lines of the pattern. Desirably, they should appear to have the same width and height, composition and location as the extension lines 50a. Like extension lines 50a, the extra pattern lines 50b are electrically isolated from any of the power feeds as well as any of the OLED bottom electrode segments and do not directly control, participate in or supply power for the operation of the OLED segments. The space or gap that electrically isolates the extra pattern lines 50b is filled with electrical insulating layer 15. For example, in 200, there is an extra pattern line 50b present between P4 and P5 that crosses SI and S3 and two extra pattern lines 50b between P2 and P6, but which are not associated with any power feeds.

[0076] Moreover, it may be necessary that that part of an extra pattern line 50b may be located within a gap 5 and may not extend completely across the array. For example, see the extra pattern line 50b to the right of P4 in Fig. 3 A which may in part be located within the gap 5 between S4 and S5 in order to maintain a uniform pattern. In such cases and under some viewing conditions (for example, when the array is emitting as shown in Fig. 3B), the gap 5 may be part of the visible pattern.

[0077] Fig. 3 A (like Fig. 2A) shows 200 is an unlit, non-emitting state where, assuming that gap 5 (according to layer 17) is transparent, opaque power feeds P3 to P7 along with the associated extension lines 50a or extra pattern lines 50b form a visible (due to reflected ambient light) uniform pattern of evenly spaced lines 50 that extend across all the OLED segments within the array. The visible pattern of evenly spaced parallel lines 50 is composed of the power feeds and their associated extension lines 50a, extra pattern lines 50b and in part, gap 5.

[0078] Fig. 3B (like Fig. 2B) shows 200 in a lit, emitting state where, since the gap 5 is nonemitting, it becomes much less noticeable than the emitting segments SI to S7 and effectively appears dark and part of the visible pattern. At lower levels of emission, the power feeds P4, P5, P6 and P7 along with extension lines 50a and extra pattern line 50b will be visible running across all of the OLED segments within the array in a regularly spaced pattern. In this instance, the non-emitting gap 5 can appear to be part of the pattern of power feeds and extension lines 50a. For example, the gap between S4 and S5 can appear to be a linear extension of the line 50b that crosses SI and S3. Similarly, the gap between segments SI and

[0079] 52 (where power feed P3 is located) can also appear to part of the same line 50a that crosses

[0080] 53 and S5. In such cases, the gap 5 should be designed to be about the same width as the extension lines or as close as possible.

[0081] Fig. 3C is a cross-sectional view of 200 along line x-y as indicated in Fig. 3 A. It is similar to the view of 100 as shown in Fig. 2C with the addition of extra pattern lines 50b above the transparent substrate 10 and below the bottom electrode segments 20 of SI and S2. The relative spacing between power feeds P3 to P6 and the extra pattern lines 50b are adjusted to be a constant distant d. In this example, the same distance d is maintained between the edge of the emissive area of the OLED array and the nearest visible line (which are power feeds P4 and P7). Although this is desirable, it is not always necessary and the distance between the pattern of visible lines 50 and the edge of the OLED array need not be limited to the same spacing d used between the visible lines.

[0082] Fig. 3D is a cross-sectional view of 200 along line x’-y’ as indicated in Fig. 3 A. In this view, extension line 50a (associated with P3) can be seen running under S3 but is not in contact with S3. Because an even, regular pattern of lines is less noticeable than an uneven, irregular pattern, the inventive device 200 will appear to be more slick, smooth and finished in an unlit state as well an emissive state, at least at lower levels of emission.

[0083] In order to further reduce the noticeability of the visible pattern of lines formed by some combination of power feeds and extension lines and possibly extra pattern lines (and under some conditions, gaps), it would be desirable to have that part of the pattern that lies under the OLED bottom electrode segments to equally divide the light output of the emission area of the overlying OLED segment when possible. For example, a single visible line would appear to divide the OLED segment into 2 equal parts, two visible lines would appear to divide the OLED segment into three equal parts, etc. It is important to note that the presence of the visible line (located within the emission pathway) is not in direct contact with the OLED segment; the effect is that the line, being opaque, partially blocks the light being emitted from an undivided OLED segment.

[0084] Figs. 4A illustrates this type of embodiment for segmented OLED array 300 in an unlit condition. 300 has 3 rows of OLED segments, where row 2 is laterally offset from rows 1 and 3. Power feeds (indicated by a solid line) for all of row 1 are located from the edge of the substrate to the bottom segment. The power feeds for all of row 2 pass between the OLED segments in row 1. The power feeds for row 3 are located so that they each bisect the light emission from the overlying OLED segment in row 1 (that is, it is equidistant from either opposing edge) and continues through the gaps between the segments in row 2. The lines created by these power feeds are then continued by the addition of extension lines 50a (indicated as a dashed line). In order to complete the line pattern, an electrically isolated extension line 50a is added to bisect the emission from the OLED segments in row 3. In this way, a pattern of equally spaced lines across the entire array is created where the lines bisect the OLED segments. Depending on the transparency of the gaps between the OLED segments, all of these lines may be visible in a non-emissive state. However, they will be less apparent or noticeable because the evenly spaced line pattern is regular and the OLED segments are equally divided.

[0085] Fig. 4B shows 300 in an emissive state where only the lines that are in the emission pathway of the OLED segments will be readily visible. In this embodiment where the gaps between the OLED segments are relatively large, the visible pattern of lines 50 (formed from the power feeds and extension lines 50a as shown in Fig. 4A) will appear different from the same device in an unlit condition. The visible pattern will still equally divide the emission areas of the OLED segments and still be regularly spaced but will be in an offset pattern. It should be noted that in this example, the visible pattern of lines does not extend continuously across all segments within the array. Alternatively, the width of the gaps can be adjusted so that they will visibly appear as part of the overall pattern of regular spaced lines. In any case, because all segments are uniformly bisected by the opaque lines in a regular even spaced pattern, its appearance will be slicker and more finished compared to an irregular pattern.

[0086] However, locating the power feeds so that they evenly divide the emission from the overlying OLED segments into equal parts may not always be possible depending on the layout, shapes and sizes of individual OLED segments in the array. The problem and some potential solutions are illustrated in Figs. 5A-5B and Figs. 6A-6B.

[0087] Fig. 5A shows an OLED array 400 in an unlit state. It is similar to 300 in Fig. 4A except that row 2 is not offset from rows 1 and 3 so that all OLED segments are vertically aligned. In this case, the power feeds for row 3 cannot bisect the segments in row 2 since it would then be necessary to overlap the power feeds for row 2 underneath the OLED segments in row 1. In order to prevent electrical contact between power feeds, they need to be laterally offset from each other. Thus, the power feeds for row 2 and 3 (solid lines) underneath the segments of row 1 will divide the emission of the segments in row 1 into 3 equal parts. In order to extend the visible pattern of power feeds, it is then necessary to have one extension line 50a (dashed line) and one power feed under the segments in row 2 and two extension lines 50a running under the segments in row 3. It should be noted that in Fig. 5 A, the pattern of visible lines 50 is composed of the power feeds and their extension lines 50a that are set in an evenly spaced set of two visible lines across the entire vertical column of segments, each set of two lines being evenly spaced apart.

[0088] Fig. 5A also shows extra pattern lines 50b (dashed line), which are optional, in the gaps between the columns of segments. These visible lines are not part of the first pattern due to the set of two power feeds / extension lines as described above, but rather form a second pattern which is independent of the first pattern. In this embodiment, the two patterns overlap each other over the entire emitting area of the array. Both patterns are each composed of evenly spaced parallel lines even though the spacing in each is different. The addition of this second pattern helps to maintain an overall slick and finished appearance when the gaps between segments are wide.

[0089] Fig. 5B shows the OLED 400 in an emitting state. Because of the opaque power feeds that lie withing the emission path, each OLED segment appears to be divided in three equal parts. The extra pattern lines 50b, located in the gaps, are not readily visible and the second pattern disappears leaving only the first pattern. Figs. 6A (unlit) and 6B (lit) shows an OLED array 500. It is similar to 400 in Fig. 5A except that the pattern of power feeds and extension lines 50a is different. In 500, the power feeds for row 3 are located in the gaps between the columns of OLED segments of rows 1 and 2. This allows the location of the power feeds (solid lines) / extension lines (dashed lines) in rows 1 and 2 to be the same as in 300. However, the relative locations of the gaps and the segments require that the power feeds for row 3 to be bent within the gap in order to make contact with the OLED segments as shown in the enlarged view (for clarity, the vias are not shown). Also shown in the enlarged view are extension lines 50a that visibly extend the linear pattern of the power feeds for row 3 but are not in contact with the power feeds. Fig. 6B shows 500 in an emitting state so that it appears the same as 300 in Fig. 4B where the segments appear to be bisected by the power lines 50 as opposed to 400 in Fig. 5B where the segments are divided into three parts.

[0090] It should be noted that allowing some degree of non-linear deviation of the power feeds within the gap can still allow for a linear pattern, particularly in an emitting state. In many embodiments such as 500, locating power feeds within the gap is often desirable even if requiring some section of the power feed to be non-linear. For example, Fig. 7 illustrates a partial view of a section of an OLED array where it is desirable that a power feed is located within the gaps of different OLED segments and has multiple kinks or bends. The linear pattern can still be maintained with appropriate extension lines.

[0091] Figs. 8A and 8B are directed to an OLED array 600 with ten OLED segments (SI to S10 with their individual power feeds Pl to P10) which are irregular in shape and location. This example will illustrate some of the tradeoffs between features that might be necessary to maintain the pattern of visible lines.

[0092] In Fig. 8A (unlit), the power feeds (solid lines) for S2 to S7 in OLED array 600 are located within the gaps but run under the segment SI. In this embodiment, there are two power feeds within each gap and, as in 500 of Fig. 6A, must have a small non-linear extension in order to make contact through a via (not shown) with the OLED segment. Two extension lines 50a are used to complete the pattern within the gaps and under S10 but, as shown in the expanded view, do not make contact with the power feeds. It should be understood that since the power feeds are relatively narrow in width, a single extension line (whose width can be adjusted if necessary) can be used to extend the visible line created by two or more parallel power feeds. In this embodiment, the visible pattern of lines 50 consists of parallel double lines (which are close together) where the grouping of double lines is evenly spaced apart by a constant distance d. Fig. 8B shows 600 in an emissive state where the power feeds within the gaps are not readily visible. A linear pattern of visible lines 50 runs under SI and S10 but are not apparent in any the segments located between them. However, the visible lines under SI and S10 are in line with the gaps which will appear to be part of the pattern. This is desirable since it maximizes emission from segments S2 to S9 since there are no visible lines crossing underneath them in the emission pathway.

[0093] OLED array 600 also illustrates that the visible pattern of evenly spaced parallel lines of constant width that appear to continuously extend across all of the active areas from one OLED segment to another within the array need not be physically continuous across all intermediate segments. Sections of the visible lines can be missing so long as the appearance of the sections that are present is maintained as remaining in register with each other as if they fell along the same line (as in 600). In some embodiments, the gaps between the segments can be used as a substitute for the missing sections of the pattern. This is because the human vision system can “fill” in missing sections and cause an impression that the line is complete.

[0094] OLED array 600 also illustrates that in some embodiments, the power feeds can be located along the outside edge of the OLED array. For example, the power feeds for S8-S10 are located between the outside of the OLED array and the edge of the substrate. Power feeds along the outside edge, yet within the encapsulation, may not be part of the pattern since this area is generally not visible even when unlit. This edge area is generally covered by the array mounting or holding arrangement or can be covered by opaque tape, etc.

[0095] Figs 9A (which is an unlit view) and 9B (which is a lit view) illustrate an OLED array 700. There are 8 OLED segments S1-S8 with their individual power feeds P1-P8. This embodiment illustrates that there can be two overlapping patterns of parallel evenly spaced lines that are set at different angles to each other.

[0096] In 700, parts of power feeds P5, P7, P3 and P8 are located along the edge of the device. Thus, these portions of the power feeds will not be visible and so, will not be part of the visible pattern. Other parts of P5, P7, P3 and P8 are located in the gaps between the OLED segments that are at an angle to other gaps in the array (because of the shape of the OLED segments). These power feeds are extended using extension lines 56. There is also an extra pattern line 54 that is not associated with any power feed. However, power feeds P2, P4 and P6 run under OLED segment SI. Extension lines 58 extend these lines under S2 - S8. As illustrated in the enlarged view, the extra pattern line 54 is separated from the power feeds (P2 in this view) by a gap so there is no electrical contact between them. In 700, there is a first visible pattern of three evenly spaced parallel lines 50 formed by S5 / 56, S3 / 56 and the extra pattern line 54 between SI and S2 / S4 / S6. There is also a second visible pattern of three evenly spaced parallel lines 51 formed by P2 / 58, S4 / 58 and S6 / 58. The first and second visible patterns are set an angle to each but the power feeds in each pattern remain electrically isolated from each other and those in the other pattern. In this case, since the extension lines 56, 58 are not in electrical contact with any of the power feeds in either pattern, it is not necessary to have a gap between them at any intersections or crossings.

[0097] In the lit view of 700 (Fig. 9B), only the first pattern 50 will be visible under some conditions since the second pattern 51 is entirely located within the non-emitting gaps and not readily visible. Note that because of the irregular layout of the array, OLED segments S2-S6 will be bisected by visible lines, but OLED segments SI and S8 will be irregularly divided. However, since the pattern of parallel visible lines extend straight across all the segments in register, it will still be perceived as being even and regular and so, less noticeable.

[0098] Figs 10A (unlit) and 10B (lit) illustrate an OLED array 800 with nine OLED segments S1-S9 with corresponding power feeds P1-P9. In 800, it is desired that the border area surrounding the OLED array is very small with insufficient room for any power feeds. Except for the edge with the contact pads, the remaining power feeds must run under the array.

[0099] In order to form a regular pattern of lines, all of the power feeds within the array should have the same width. However, in 800, OLED segment S9 is very large and will require more power than any of the other OLED segments. In order to supply enough power to S9, a wider power feed may be needed and so, all of the power feeds would need to be wider than necessary. This would decrease light emission, which is undesirable.

[0100] 800 illustrates the use of multiple common power feeds to supply sufficient power to a large segment without increasing the width of the power feeds to other, smaller segments. In 800, a number of common power feeds of a narrower width can serve as a single individual power feed. For example, the individual power feed P9 for S9 has two separate contact pads P9a and P9b which receive the same signal from the external driver. In turn, P9a and P9b are then each split (outside the array area) into two smaller common power feeds than are located under SI and S5 and make contact with S9 for a total of four contact points. This allows S9 to receive power from four dispersed vias compared to a single via like the other segments in the array. All the lines making up P9 would still be considered an individual power feed since all lines are common, carry the same signal and are in contact with only one electrode segment. However, the downside is that this approach would require more visible lines and so, reduce the amount of emission.

[0101] In order to reduce the number of visible lines in 800, the split power feeds P9 are located near the edge of the array. By this arrangement, there are then two different patterns in different parts of the same array.

[0102] The first pattern is in the center portion of the array (S2-S4 and S6-S8) where power feeds P6 bisects S2 and S6, P7 bisects S3 and S7, P8 bisects S4 and S8 and associated extension lines 50a extend the lines of the power feeds across S9. In the first pattern, the visible lines 50 can be spaced further apart within the center portion of the display.

[0103] The second pattern is along the outside edges of the array where contact pads P9a and P9b are each split into two common power feeds P9 and divide the emission from SI and S5 into three equal parts. Associated extension lines 50a complete the linear pattern of each of the common power feeds from P9 and P9’ across S9. The second pattern is then formed by the visible lines 51 resulting from the four separate but common power feeds P9 and associated extensions lines 50a. In the second pattern, the spacing of the parallel lines is smaller than in the first pattern.

[0104] 800 is an example where the distance between the visible lines in the more important center region of the array can be increased with a corresponding decrease in the spacing of the visible lines along the edges of the display. It is most desirable that a single visible pattern of evenly spaced parallel lines is present across the entire array. However, in many arrangements, compromises must be made and more than one pattern may be necessary for various reasons. In this case, it is known that according to the human visual system, the center region of the field of view is more important than the edges of the view.

[0105] If it is necessary to have only part of the total emission area of the array covered by the pattern and the remainder has no pattern or if two (or more) visible patterns are necessary, it would desirable that one visual pattern predominates; that is, greater than 50% of the total emission area of the array be covered by the primary pattern. In both situations, it would be desirable to have the predominate primary visual pattern located in the center of the emission area of the array; that is, any secondary visual pattern is located along the outside edges of the emission area of the array.

[0106] In such cases, the primary visible pattern can have parallel lines spaced apart by a distance (d) while the secondary visible pattern can have parallel lines spaced apart by a different distance (d’) where d’ d. It is preferable that d’ be smaller than d since more space between the visible pattern increases the amount of light emission in the center region. Figs 11 A-l ID illustrate an OLED array 900. There are 18 triangular OLED segments S1-S18 with their individual power feeds P1-P18. 900 has two overlapping patterns of parallel evenly spaced lines that are set at different angles to each other to form a visible grid as in 700 (see Fig. 8A), but the overlapping patterns are created using a different layout.

[0107] In Fig. 11 A (unlit), vertical power feeds Pl, P3, P5, P7, P9, PH, P13, P15 and P17 (solid lines), and their associated extension lines 62a (dotted lines) are all located perpendicular to Edge 1 and make contact through vias (black dot) to corresponding OLED segments SI, S3, S5, S7, S9, Sil, S13, S15 and S17. There are vertical extra pattern lines 62b within the gaps between the segments in the same direction to maintain the spacing of visible lines. Together, these power feeds / extension lines 62a, extra pattern lines 62b create a first pattern (in a vertical direction) of evenly spaced parallel lines 51. The contact pads for these power feeds extend to edge 1 of the substrate past the encapsulation 35.

[0108] There is also a second (horizontal) pattern of visible lines perpendicular to the first (vertical) pattern. Horizontal power feeds P14, P8, P2, P16, P10, P4, P18, P12 and P6 (solid lines) are all located perpendicular to Edge 2 and make contact through vias (black dot) to corresponding OLED segments S14, S8, S2, S16, S10, S4, S18, S12 and S6. There are extension lines 60a (dotted lines) that visibly extend the direction of power feeds to create a second (horizontal) pattern of evenly spaced parallel lines 50. There are also horizontal extra pattern lines 60b (located within the gap) to maintain the even spacing of the second pattern. Although the contact pads for these power feeds are shown as being along Edge 2, the contact pads for power feeds could also be located on Edge 1 by extending and redirecting the lines along the edge of the substrate (parallel to Edge 2). Thus, there is a second horizontal pattern of evenly spaced lines 50 consisting of power feeds P14, P8, P2, P16, P10, P4, P18, P12 and P6 and their associated extension lines 60a and extra pattern lines 60b.

[0109] However, while the visible impression of 900 (either unlit or lit) is of a uniform grid, the first and second patterns are separated vertically in space and there is no electrical contact between them. The second pattern is set at a right angle to the first pattern to create the visible impression of an evenly spaced square grid of parallel lines since the distance between the visible lines is the same in both patterns. Note that this grid pattern makes no contact with the overlying bottom electrodes of the OLED segments (except at the one via for each power feed) and does not act as an auxiliary electrode.

[0110] Fig. 1 IB (lit) illustrates where the visual appearance is of an evenly spaced grid of visible lines 51 (vertical direction) and 50 (horizontal direction) that is superimposed over the light emitting array of OLED segments and where those sections of the power feeds / extension lines or extra pattern lines located within the gaps are not visible.

[0111] Fig. 11C is a cross-sectional view of 900 as seen from Edge 1. Visible on the substrate are the ends / contact pads of power feeds Pl, P3, P5, P7, P9, Pll, P13, P15 and P17 along with two extra pattern lines 62b that are unassociated with any power feeds. When viewed from above (Figs. 11 A and 1 IB), these (together with the extension lines 62a associated with the power feeds) will form the first (vertical) visible pattern 51. Also visible are the via VI which connects Pl to the bottom electrode segment 20 (SI), via V7 which connects P7 to the bottom electrode segment 20 (S7) and via V13 which connects P13 to the bottom electrode segment 20 (S13) since these are the OLED segments closest to Edge 1. Above the plane of the power feeds, extension lines, and extra pattern lines that form the first pattern and behind VI, V7 and V13, the side of power feed P14 (which is part of the second pattern) along with its external contact pad P14’ can be seen. P14 extends from Edge 2 to below the edge of the bottom electrode 20 of OLED segment S14 (the edge of which can be barely seen behind 20 of S13) and connects through via V14. Extension line 60a continues the line of P14 in the same plane to the far edge of the device. Also shown are the other vias V3, V5, V9, VI 1, V15, and V17 for the OLED segments farther away from Edge 1. The remainder of the device is the same as shown in Figs. 2C and 3C.

[0112] Fig. 1 ID is a cross-sectional view of 900 as seen from Edge 2. Visible on the substrate (see Fig. 11C) is the end / contact pads (P17’) of power feed P17 as well as extension line 62a. Power feed P17 is electrically connected to segment S17 through via V17. Directly behind P17 (so not visible) are the other power feeds / extra pattern lines P15, P13, 60b, Pll, P9, P7, 60b, P5, P3, and Pl that form the vertical pattern 51. Above and electrically isolated from the power feeds / extension lines on the substrate (see Fig. 11C) are contact pads (which are located on a shelf of insulating layer 15) / power feeds P14, P8, P2, P16, P10, P4, P18, P12 and P6 along with two extra pattern lines 60b that are unassociated with any power feeds, When viewed from above (Figs. 11 A and 1 IB), the power feeds P14, P8, P2, P16, P10, P4, P18, P12, P6, their associated extension lines 60a, and extra pattern lines 60b will form the second (horizontal) visible pattern 50. In this view, the vias are not shown.

[0113] It should be noted that in Figs. 11C and 1 ID, all of the power feeds and extension lines are fully surrounded by electrical insulating layer 15 (except where those of the second pattern are in contact with substrate 10). In practice, the power feeds and the associated extension / extra pattern lines of the first pattern are patterned on the transparent substrate and fully covered by the insulation layer 15. The power feeds, extension lines / extra pattern lines of the second pattern are then patterned over the top of the insulation layer. The second pattern is then fully covered by more of the insulation layer 15. In this way, the first and second patterns of lines occupy different vertical spaces within the insulation layer and there is no electrical contact between any of the power feeds in either pattern alone or between the different patterns. Moreover, the insulation layer 15 prevents electrical contact of the power feeds with any of the bottom electrodes 20 except through a via from the appropriate individual power feed. The same composition of insulation layer 15 can be present between the top of the transparent substrate and the bottom of the electrode segments 20 / PDL 17 throughout, or different electrical insulations materials may be used in two or more layers.

[0114] This invention relies on the human visual system response to regular patterns of parallel lines. The most important characteristics are the spacing d (distance between the lines), frequency (number of lines over a given distance), the width of the lines and the contrast of the lines (difference in opacity between the lines and the background). In general, spatial patterns small enough, and / or viewed far enough away, will not be visible. For example, some computed examples (italicized values indicate non-visible patterns):

[0115] As a further illustration, the image below has four quadrants. The top left quadrant has a pattern of thick lines spaced evenly but well apart. The bottom left quadrant has thinner lines spaced closer together. The top right quadrant has even thinner lines spaced even closer yet. The bottom right quadrant has the thinnest lines that are very closely spaced. Clearly, the visibility of a pattern becomes less noticeable as the width of the lines and the distance between the lines (the period of the pattern) decreases. Regardless of the period, as the thickness of the lines in the pattern is increased as a proportional of the period of the pattern (effectively, increasing the coverage area), this will manifest as a reduction in luminance.

[0116]

[0117] Clearly, the visibility of a pattern becomes less noticeable as the width of the lines and the distance between the lines decreases. As the lines of the pattern become reduced in width and closer together, the changes will manifest as luminance differences.

[0118] The visual acuity limit is about 60 cycles per degree (cpd), meaning 60 line pairs per degree of visual angle, or equivalently any periodic pattern of 1 cycle per minute of visual angle. Visual angle is a function of both the physical size of the pattern and the viewing distance. Spatial frequency in cpd can be computed from line spacing as follows: f = 2*tan (0.5)*D / p where f is the spatial frequency in cpd, D is the viewing distance, and p is the period or line spacing (also referred to as distance d), with matched units of length for D and p. Peak visual sensitivity is about 3-5 cpd, and sensitivity falls off quickly at higher frequencies. Some references on the visibility of periodic patterns based on contrast, size, luminance, and other factors include: P.G.J. Barten, Formula for the Contrast Sensitivity of the Human Eye in Image Quality and System Performance, Proc, of SPIE-IS&T Electronic Imaging, SPIE Vol. 5294 (2004) and R.K. Mantiuk et al, A Unified Model of Contrast Sensitivity as the Function of Spatio-Temporal Frequency, Eccentricity, Luminance and Area, ACM Trans. Graph. 41, 4, Article 145 (July 2022).

[0119] It is anticipated that in the case of large arrays, it will be necessary to have multiple power feeds / extension lines / extra pattern lines in the emission pathway of each OLED segment, for example, in an array with 224 OLED segments (64 hexagons @ 21 mm2, 16 half-hexagons @ 10 mm2and 144 triangles @ 3mm2for a total area of 1936 mm2), 224 individual power feeds are required and only a few can be located within a gap. In this example, the hexagon segments will be crossed by 26 visible lines, the half-hexagons 16 lines and the triangles 12 lines. In a large array (100 or more OLED segments), each OLED segment within the pattern of parallel lines may have as few as one visible line or as many as 50 visible lines, depending on the size of the individual segment.

[0120] Since there are opaque or light-blocking power feeds and extension lines or extra pattern lines located in the emission path, the total overall amount of emission from the OLED array will be impacted due to a large number of lines, particularly at a close spacing. Desirably, the presence of the power feeds and extension or extra pattern lines cause no more than a 30% loss in overall emission (compared to no lines being present) and more desirably, no more than a 25% loss and most desirably, no more than a 20% loss.

[0121] It is desirable that all segments within the array, or at least, within a single pattern, have no more than a JND in peak luminance. Note that generally a relevant luminance range for a just-noticeable difference (JND) is about a 1% luminance difference (equivalent to 1% difference in (1-coverage). For example, for 18.5% coverage, transmitted intensity is 0.815 so that 1% = 0.008, so the intensity (proportional to luminance) difference would be a JND. Preferably, all segments should have a peak luminance in cd / m2preferably of + / - 10% and more preferably, + / - 5% if the distance between the parallel lines is 2 mm or greater, or preferably + / - 1% if the distance between parallel lines is less than 2 mm without regard to the % loss caused by the presence of opaque lines in the emission pathway.

[0122] The spacing between the parallel visible lines in the pattern is highly dependent on the layout and number of OLED segments in the array as well as the width of the visible lines. At a minimum, the spacing d between the parallel lines should be at least 0.05 mm (50 pm) and a maximum of no more than 10 mm, preferably, no more than 5 mm and most desirably, no more than 1 mm.

[0123] The width of all visible lines should appear to be constant within the pattern; that is, the width of the lines does not need to be physically constant in width so long as there is no noticeable or apparent variability along the length of the lines or between lines. The width of the power feeds should be 5 pm or greater, and desirably in the range of 0.005-1 mm. The height of the power feeds should be 0.03 pm or greater, and desirably in the range of 0.1-2 pm. It should be noted that if the power feeds are opaque and block 100% of the light, the height of the individual power feeds may be different from each other with little effect on their visibility. This is useful for minimizing IR drop over the power feed. At a minimum, the width of the non-emitting gap 5 should be similar to the width of the visible lines (or if grouped together, the width of the grouping) if the gap is part of the pattern. If not part of the visible pattern, it should be significantly wider than a visible line by at least 5X. A desirable range for the width of a non-pattem gap is at least 0.005 mm and 20 mm or less, preferably 2 mm or less, and most preferable 0.25 mm or less. It is desirable that the width of the gaps between all OLED segments in the array be constant whenever possible.

[0124] There are two well-known phenomena that can impact the visibility or noticeability of a pattern of evenly spaced parallel lines. The first is spatial frequency adaption. Some general reviews can be found in: SEEING THE LIGHT: Optics in Nature, Photography, Color, Vision and Holography, D.S Falk et al, John Wiley & Sons, 1986: Chapter 7.8, “Channels, Spatial Frequency and Tilt”; Emergent Techniques for Assessment of Visual Performance, Committee on Vision, National Research Council, NATIONAL ACADEMY PRESS Washington, D.C. 1985; and Perception Lecture Notes: Spatial Frequency Channels (Professor Michael Landy) - see spatial frequency adaptation, the perception of a regular pattern by human visual system decreases over time. A regular pattern is required, and the human eye has to scan around the pattern to induce adaptation. In spatial frequency adaptation, the spacing / frequency of the parallel lines are most important and often described in terms of a sine wave. A secondary consideration is often the “sharpness” of the line; that is, whether the edges of the line are clearly defined (in terms of density difference over a distance) or more diffuse.

[0125] The second phenomenon of importance is the Poggendorff Illusion (see https; / / en. wikipedia. orgAvikj / Poggendorff nij.isiou) which is an optical illusion that involves the brain's perception of the interaction between diagonal lines and horizontal and vertical edges. The typical example is where a thin line occluded by a thicker line appears offset and either discontinuous and / or different in angle. The Poggendorff illusion depends on the steepness of the intersecting lines. As obliqueness is decreased, the illusion becomes less compelling.

[0126] Fig. 12A illustrates the problem due to the where the evenly spaced parallel lines of the pattern overlay the thicker (non-emissive) gaps between the OLED segments. Depending on the shape of the OLED segments and their arrangements within the array, the sides of the OLED segments may not be perpendicular to the visible lines of the pattern. In Fig, 12A, OLED segments with parallel lines covering about 20% of the area are shown with several different gaps at different angles to the lines. The visible lines are linear across the segments and the gaps. If the angle between the segment boundary and visible line is 90 degrees, the visible lines appear to continue linearly across the segments. However, at 30 degrees, the visible lines appear to be non-linear at the boundary of the gap. The effect is less noticeable at 45 or 60 degrees. In particular, the visible line seems to be offset to some degree on opposite sides of a segment due to the Poggendorff Illusion. It has the appearance of being unsmooth with a sawtooth effect.

[0127] Fig. 12A shows visible lines that are physically aligned across segment boundaries, but the thin lines crossing the thick gaps between OLED segments at 30 and 45 degrees appear offset and discontinuous. The offset is stronger for smaller angles. Fig. 12B show one solution for when the Poggendorff Illusion is noticeable and objectionable. In Fig. 12B, the visible lines in the bottom segment with the arrow has been shifted slightly to the right, which visually makes the lines look more continuous across the 60-degree boundary. It should be noted that although the visible lines in this example no longer physically aligned as single continuous line, it appears to be more continuous. In this example, it is important to note that it is the visual appearance of the pattern of evenly spaced parallel lines that is important and not the actual physical layout of the lines.

[0128] The appearance of a regular line pattern can be affected by the shape (corresponding to the edge of the line as viewed from above) or sharpness (the vertical height) of the edge profile of the line. A square-wave intensity (equivalently, luminance) pattern along a straight edge of the line between fully -lit and fully-opaque edge regions appears sharpest, while a line edge with a sinusoid variation in intensity will appear softer and less visible. Intermediates between these extremes can be achieved by utilizing semi-transparent, sawtooth or irregular edges. It should be noted that such variations in edge profile (either along the edge or the vertical slope of the edge) would be small compared to the width of the line and will not be readily visible at reasonable viewing distances.

[0129] Contrast (also referred to as amplitude, or modulation) has a huge effect on visibility of a periodic pattern. However, in this case, the power feeds / extension lines / extra pattern lines of the visible pattern will have high contrast relative to the background (the OLED segments and gaps). If the visible lines are opaque to light, the contrast is not readily adjustable and is conceptually infinite. It should be noted that the contrast of the visible lines can be dependent on ambient light effects. If the composition of the visible lines is metallic and reflective, it could end up brighter than the lit area in the right lighting condition. If it is matte black, it may reflect a small amount of light, reducing the contrast somewhat but would make the appearance more consistent as the lighting varies. The contrast of the visible lines can also be varied by diffusion. Using an optical diffuser such as a scattering medium or a textured surface, between the OLED and the viewer, would create both lower-amplitude and softer-edged lines. However, this will affect the overall “look” of the array when emitting. Contrast of the visible lines can also be reduced by forming gaps or holes within the body of the lines to enable at least some light to pass through. For example, holes can be etched in the body of the lines. Alternatively, the visible line may be divided into two or more closely spaced parallel lines separated by a small gap to allow some light to pass. In this case, the spacing would be small enough so that it appears to be a single line at an appropriate viewing distance. As another alternative, the edges of the lines can be made non-uniform so that they appear to be fuzzy or indistinct. In yet another alternative, the edges of the line can be made thinner than the center so the edges become partially transparent. In any case, the thickness of the conductive line can be adjusted to maintain conductivity as necessary.

[0130] It is most desirable that a single evenly spaced visual pattern of parallel lines is superimposed over the entire emitting area of the segmented OLED array. However, this is not strictly necessary to still make the visible lines less apparent or noticeable. In many arrangements, compromises must be made and partial patterns or more than one pattern or may be necessary for various reasons.

[0131] In practice, some deviations to the overall pattern are acceptable, particularly if small in terms of the amount or size of the deviation relative to the size of the overall emitting area of the array. It would be desirable to have the visible pattern of evenly spaced parallel lines of constant width superimposed over at least 70% of the total emitting area of the array, and more desirable, over at least 80% and most preferably at least 90%. The remainder of the emitting area of the array can have no pattern of visible lines.

[0132] In some embodiments, there can be two or more patterns where one will be the predominate primary pattern and the others are secondary patterns. When there is one primary visible pattern of evenly spaced parallel lines of constant width and one or more secondary visible patterns, it is desirable that the primary pattern is superimposed over at least 51% of the total emitting area of the array. It is desirable if each segment has a consistent visible pattern, with a majority of segments having the primary pattern and a minority of segments having the one or more secondary patterns.

[0133] An alternative arrangement of a combination of segments with different visible patterns is a regular alternation, where a segment or group of segments with a primary pattern is regularly alternated with a segment or group of segments with a secondary pattern. This could take the form of a striped arrangement or checkerboard arrangement of differently- patterned segments.

[0134] Another alternative arrangement of a combination of segments with different visible patterns is a gradient pattern, wherein a group of segments near one edge of the array (for example the top) has a primary pattern of visible lines, and an adjacent group of segments has a secondary pattern of visible lines. Further adjacent groups of segments have additional secondary patterns, so that the resulting visual effect is a gradient in one of: line pattern period, line thickness, line coverage area, or luminance.

[0135] It is known that according to the human visual system, the center region of the field of view is more important than the edges of the view. 800 is an example where the distance between the visible lines in the more important center region of the array can be increased with a corresponding decrease in the spacing of the visible lines along the edges of the display. If a primary visual pattern is not superimposed over the entire light-emitting area of the array, it would be desirable that the primary pattern is located in the center of the array and any deviations or secondary patterns be located within 20%, preferably with 10% and most preferably 5% of the total distance of the array to the nearest edge. It is desirable that the secondary pattern be limited to the segments adjacent to the array edge or that are contiguous with edge segments. For example, if the total emitting area of the array is 100x200 and the desired distance from the edges is 20%, then the derivations or secondary pattern should be restricted to be within 20 of the edge in the 100 direction and within 40 of the edge in the 200 direction. There may be boundaries or spaces between patterns.

[0136] In such cases, the primary or predominate visible pattern can have parallel lines spaced apart by a distance (d) while the secondary visible pattern can have parallel lines spaced apart by a different distance (d’) where d’ d. It is preferable that d’ be smaller than d since more space between the visible increases the amount of light emission in the center region.

[0137] It is desirable that the evenly spaced parallel lines of a visible pattern extend from one edge of the light-emitting area of the array to the opposite edge so that the lines of the pattern are visible in the emission of all OLED segments along that line. However, it is not always possible that the visual pattern extends entirely across the entire light-emitting array and there may be missing sections within the visual lines. For example, see Figs. 8A and 8B. In such cases, it would be most desirable that the visual lines appear to remain in register. That is, the visual line will appear to be straight even if there are large missing sections or are physically offset (to compensate for the Poggendorff Illusion). This is because the human visual system tends to ignore the missing sections of lines when they appear to be register. In some cases, missing sections of a visual line may appear to be replaced with a gap between the OLED segments; in such cases, the gap should be in line with the visible sections of the line in the pattern. It should be noted that the visual pattern is not necessarily limited to individual single lines spaced the same distance apart. For example, three parallel lines (created by the power feeds / extension lines / extra pattern lines) may be spaced closely together a small distance apart. A number of such groupings of three individual lines may be spaced at a greater distance apart. When viewed closely, this would form a visual pattern of a grouping with three lines regularly spaced apart. However, when viewed at a greater distance, each grouping of three lines closely spaced together would appear to merge into a single wider line and so the visual pattern would appear to be single lines regularly spaced apart. In both cases, the visual pattern of lines would appear to be regular and so, less apparent or noticeable.

[0138] The transparent substrate 10 can be glass (including flexible glass) or polymeric materials. Generally, it will be flat with a uniform thickness. The top surface of the substrate is that facing the OLED. Since the substrate will be part of the overall encapsulation for the OLED, it should be sufficiently impervious to air and water so that the OLED will have desired lifetime. The substrate can be rigid or flexible. The substrate may have various types of subbing layers (i.e., planarization layers, light management layers, etc.) which may be patterned or unpatterned and can be located either on the top or bottom surfaces. Rigid or flexible glass is preferred.

[0139] All or part of the individual power feeds for each OLED segment may be located within the emission pathway of another OLED segment (although electrically isolated from it) and will form part of the visible pattern. To be within the emission pathway, the power feed will either be located between the bottom electrode of an overlying OLED segment and the transparent support (outside the OLED segment) or within the OLED segment between the organic light-emitting layers and the bottom electrode. When located within the OLED segment, the power feed will be electrically isolated from both the organic layers and the underlying bottom electrode.

[0140] The power feeds are desirably formed before any of the organic OLED layers are applied. This is because they must be individually patterned since there is at least one power feed for each segment. One cost-effective way to manufacture the power feeds is to use photolithographic processes and techniques that are capable of forming very fine patterns of conductive structures. However, photolithography is generally not compatible when used over organic OLED layers. Fine metal masking processes and techniques can be used to create the power feeds, even over organic OLED layers, but it would be more expensive and more prone to defects during manufacture. The conductive structures created by masking processes are also significantly larger than those that can be made using photolithography. Whether the power feed is located above or below the bottom electrode, it is desirable that it is located in an electrically insulating layer.

[0141] In some embodiments, the power feeds are located between the bottom electrode and the transparent substrate. The power feeds are preferably located directly on the upper surface of the substrate. There should be only one power feed per segment. In some instances, the power feed may be split into two or more sub-feeds which are connected in different locations to the same electrode segment. In some cases, two or more separate but commonly operated power feeds (considered to be equivalent to a single power feed) may be connected to a single segment. For example, a driver with maximum output of 10mA connects to a 20 cm2segment. If the segment needs 1 mA / cm2to produce the desired light output, then this segment would need 2 power feeds (one from each driver or one each from 2 channels of a multi-channel driver). Such arrangements can help distribute the power more uniformly over the segment or reduce IR drop. However, in some instances, the same power feed can be used for two or more segments. Segments that share a common power feed cannot be activated independently and will emit in common are considered as being equivalent to a single segment.

[0142] There is an external contact area (also referred to as a contact pad) outside of the encapsulation that is electrically connected to each of the power feeds that are within the encapsulation. Although the Figures show an extension of the power feeds outside of the encapsulation that forms the contact areas, it is also possible to selectively remove encapsulation over the power feeds to make electrical contact through the encapsulation. Controlled power sources are then electrically connected (i.e., by soldering or ACF (Anisotropic Conductive Film)) to these contact areas to supply power as necessary to the power feeds and segmented electrode within the encapsulation. Delivering the appropriate amount of power to the contact areas over a suitable period of time will cause the OLED segment to emit light at the desired luminance for that period of time. The power delivered to the external contact pads is determined by a controller or driver. It is very desirable to have all of the contact pads on the same edge of the substrate.

[0143] The location and distribution of the individual power feeds across the surface of the substrate will depend on the design of the segment array. Some power feeds may be located along non-emitting areas (i.e., under the gaps and / or outside edge of the device) while others are located under or overt the bottom electrode of the segments and in the light path. Depending on the design, some segments may not have any power feeds located over or below them while other segments have multiple power feeds. Depending on their location and viewing conditions (i.e. lit or unlit), an individual power feed may or may not be part of the visible pattern.

[0144] The power feeds are at least partially opaque, if not fully opaque to light. The power feeds may be composed of any electrically conductive material that can be patterned. For example, the power feeds may be made of metal such as chromium, aluminum, silver, copper, molybdenum, tungsten, neodymium, titanium, gold or an alloy thereof, conductive metal oxides such as ITO, AZO, IZO, GZO, ZnO, TiN or SnO2, organic materials such as PEDOT:PSS, CNTs (carbon nanotubes), graphene or conductive particles such as silver, nickel or copper suspended in a polymeric binder (conductive inks) or any combination of these materials. Conductive materials can be in the form of nanowires. Ideally, the power feeds should have a resistivity of less than 25 ohms / square and desirably less than 15 ohm / square.

[0145] Desirably, the power feeds are a bilayer or trilayer with at least two conductive materials. The layers can be the same width or one can be wider than the other. For example, the power feed can be a bilayer with one layer of a conductive metal oxide and another made of a metal. As a conductive metal oxide, ITO is preferred. In one embodiment, the top layer is a conductive metal oxide and wider than the bottom layer of metal so that the edges of the bottom layer are covered by the top layer. This helps to prevent defects when covered by insulating layer 15. A suitable trilayer can be two metal layers with a different metal between them. For example, a trilayer of Cr / Al / Cr is particularly useful.

[0146] It should be noted that a visible line of a pattern can be composed of two of more power feeds for different segments where the power feeds are electrically isolated from each other. For example, a first power feed may end at the via to a first segment and forms one section of a visible line and a second power feed for a second segment may linearly extend along the same visible line created by the power feed of the first segment without any electrical contact between the two power feeds. In effect, a power feed for a second OLED segment may act as a linear extension line for a power feed of a first OLED segment.

[0147] The visible pattern may be entirely due to the power feeds alone. However, when the power feed does not extend the full length of the pattern, it may be necessary to visually extend, fill-in or complete the partial visible line created by the power line using an extension line. The extension line is separate from and not electrically connected to the power feed along the same line of the pattern and is totally different from an auxiliary electrode. An extra pattern line is similar, except it is not associated as an extension of any power feed. The purpose of the extra pattern line is to act as a “dummy line” to visibly complete the partial pattern according to the power feeds and extension lines (if present). As such, both extension lines and extra pattern lines should visibly appear to be the same as or very similar to the power feeds where included as part of the visible pattern. The extension lines or extra pattern lines can be made of any materials with similar opacity to the power feeds. However, it is most desirable that its apparent composition and location within the emission pathway should be visibly the same as or very similar to the power feeds. It should be noted that visual appearance is not always the same as being identical in all respects. For example, the visible lines created by two closely spaced power feeds might be extended using a single wider extension line.

[0148] Although the extension lines and / or extra pattern lines have no direct part in causing light emission from the OLED segments, they may serve other purposes within the device. For example, since they may be made of conductive materials, they could act as general busbars to help distribute power to a distant part of the array. As another example, they could serve as part of a passive capacitor structure, where the bottom electrode of the OLED segment is the upper electrode of the passive capacitor structure, the insulating layer is the dielectric of the passive capacitor structure, and the conductive extension lines and / or extra pattern line is the lower electrode of the passive capacitor structure.

[0149] Desirably, there is an insulating layer 15 between transparent substrate 10 and the segmented bottom electrodes 20 that surrounds the power feeds and extension or extra pattern lines or alternatively, between the upper surface of the bottom electrode and the bottom surface of a power feed. In some embodiments, the insulating layer 15 can be discontinuous and does not need to fill the space between the power feeds / bottom electrodes / extension lines / extra pattern lines. The upper surface of insulating layer 15 does not need to be planar as long as the edges under or over the bottom electrode are not sharp. The insulating layer 15 should prevent short-circuits between the power feeds / extension or extra pattern lines and any bottom electrode segments as well as from the organic light-emitting layers as necessary. For this reason, the insulating layer should have an electrical resistance of no less than 1 Mohm (MQ) and more preferably, no less than 2 Mohms. The vertical distance between the top of the power feeds / extension or extra pattern lines and the bottom electrode segments or organic layers should be greater than 0.1 microns to prevent short circuits and no more than 10 microns and ideally in the range of 1-2 micron in order to maintain a thin device. The insulating layer may be organic including polymers or inorganic, including mixtures of organic and inorganic materials or alternating layers of organic and inorganic materials. Suitable organic insulating layers include polyimides, polyacrylates, polyesters, epoxies, etc. and mixtures thereof. Suitable inorganic insulating layers or materials include SiO2, SiN, SiON, AI2O3, TiCh, etc. and mixtures thereof.

[0150] The insulating layer should be transparent. Desirably, it has a transmissivity of 90% or better. The insulating layer should not scatter light. It should not contain any particles or any particles present should be sufficiently small so that light is not scattered. The maximum amount of light scatter due to the insulating layer should be no more than 10% (measured inline where the source light is perpendicular to the substrate and compared to the total light measured in an integrating sphere).

[0151] The electrical connection between the power feed and the overlying segmented electrode is made through a via, which is a hole or pathway in the insulating materials (i.e., the insulating layer) that separate the two. The via runs from the power feed to the segmented electrode. Ideally, the via connects to segmented electrode in a location corresponding to a non-emitting area of the segmented OLED such as the edge of the electrode. The via can be formed by patterning the insulating material so as to leave at least a portion of the surface of the power feed and / or bottom electrode exposed or uncovered. Alternatively, the insulating material can be uniformly deposited and the via created by removal of the materials over the desired section of the power feed and / or bottom electrode and thus, allowing electrical contact between the two.

[0152] The via is filled with electrically conductive material. When the segmented electrode is deposited over the power feed, some of the material of the segmented electrode can fill the via to make the connection. Alternatively, the via can be filled with an electrically conductive material to contact the segmented electrode and then the power feed is then deposited to make connection. In some cases, it may be necessary to treat the power feed, prior to depositing the insulating layer, or a filled via, with a material that promotes electrical conductivity through the connection.

[0153] The length and area of the via is not critical, but should be sufficient to supply the necessary power to the segmented electrode. The via can be of any shape along the surface of the power feed. In particular, it may extend along a length of the power feed. There may be more than one via between the individual power feed and electrode segment.

[0154] For those embodiments where the power feeds are outside the OLED segment, there is an array of individual electrode segments 20 located over the insulating layer 15 in which the power feeds and extension or extra pattern lines are embedded. There may be other intervening layers present such as a refraction-reduction layer. There is a non-emitting lateral gap 5 between the individual segments on all sides (except for the ones located along the outside edge or at the corners of the device) that separates the individual OLED segments.

[0155] The segmented OLED device is a bottom emitter and the bottom electrode segments are transparent. The transparent electrode segment should transmit as much light as possible, preferably having a transmittance of at least 70% or 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 reflectivity. While the bottom transparent electrode may be made of any conductive materials, metal oxides such as ITO or AZO or thin layers of metals such as Ag are preferable. In some cases, there may be an auxiliary electrode to help distribute charge more uniformly across the area of the transparent electrode. Ideally, the electrode segments should have a resistivity of less than 25 ohms / square and desirably in the range of 10-23 ohm / square.

[0156] There is an insulating layer 17 (also referred to as a pixel definition layer (PDL)) in the gap 5 which separates parts of one OLED segment from another or along the outside perimeter of the array. For example, the PDL can separate the electrode segments from being in electrical contact, used to restrict organic layers to a single OLED segment or define the outside edge of the array. In some cases, it can be used to partially cover the electrode segment to prevent light-emission in the PDL areas (for example, in areas where the via is located along the edge of the electrode segment). PDL can also be over the power lines and extension lines to cover non-planar parts of the electrode or sharp steps in the electrode. In other cases where there is no PDL layer in the gap between the electrode segments, there still may PDL located along the outside perimeter of the array. The PDL should be insulating (electrically non-conductive).

[0157] In some embodiments, the PDL 17 in the gap 5 between the electrode segments will have approximately the same thickness as the electrode segments. This will create a relatively flat surface for depositing the overlying layers. In other embodiments, the PDL will be thicker than the electrode segments and so a section of the PDL will extend past the upper surface of the electrode segment, either in the gaps or along the outside edge of the array. In some cases, the extended portion of the PDL will also cover some part of the upper surface of the electrode surface. In such cases, the PDL may cause light piping or light guiding which would be undesired. To reduce light piping, absorbing dyes may be added to the PDL Alternatively, the PDL layer material may be opaque or black. In such a case, any power feeds located under the PDL would not be visible even when the device is non-emitting. Suitable PDL materials may be polymeric or inorganic and may be the same or different from the materials used for the insulation layer 15. Some examples of a suitable polymeric PDL include acrylic and polyimide polymers. Some examples of a suitable inorganic PDL include SiCh, SiN and SiON.

[0158] For those embodiments where the power feeds are within the OLED segment, there is an array of individual electrode segments 20 / PDL 17 located over the transparent substrate with the power feeds, extension lines and extra pattern lines (if present) located above the bottom electrodes and below the organic light-emitting layers. The power feeds are electrically isolated from the underlying bottom electrodes, from each other along with any extension lines or extra pattern lines and from the overlying organic layers by insulating layer 15 in which the power feeds and extension or extra pattern lines are embedded.

[0159] Fig. 13 shows a typical composition of OLED layer types for light emission in an OLED device 1000. There will be one or more light-emitting layers with multiple auxiliary layers to help promote and control the movement of charge between the electrodes during light emission. In this particular example, the bottom electrode segment is an anode and the top electrode is a cathode.

[0160] On a transparent substrate 10 and an insulating layer 15 with embedded power feeds and extension lines, are located an individual transparent bottom electrode segment 20. Over the transparent electrode segment, there may be a hole-injection layer (HIL, Layer 1001) as needed. The purpose of an 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 contain dopants to modify their properties. Since it is non-light emitting, it does not contain emitting materials. There is generally only one HIL present. The choice of appropriate materials is not critical and any may be selected based on their performance. One example of a suitable HIL material is HAT-CN.

[0161] Over the HIL (Layer 1001) is located a hole-transport layer (HTL, Layer 1002). The purpose of an HTL is to manage the transport of holes from HIL to the light-emitting layers 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. Since it is non-light emitting, it does not contain emitting materials. There may be multiple HTLs present. The choice of appropriate materials is not critical and any may be selected based on their performance. One example of a suitable HTL is NPB.

[0162] Over the HTL (Layer 1002) is located an exciton-blocking layer (EBL; Layer 1003) as needed. Light-emitting layers emit via the formation of excitons which in some cases, have sufficient lifetime to diffuse away from the site of its formation. The purpose of an EBL is to confine the excitons to the LEL to maximize light emission. Suitable exciton-blocking materials are well-known and commonly used. These layers may be mixtures of such materials and may contain dopants to modify their properties. Since it is non-light emitting, it does not contain emitting materials. There may be multiple EBLs present. The choice of appropriate materials is not critical and any may be selected based on their performance. One example of a suitable EBL is mCP.

[0163] Over the EBL (Layer 1003) is located a first light-emitting layer or unit (LEL1; Layer 1004) A light-emitting layer (LEL), which is a single layer, generally contains one or more non-emitting host compounds and one or more light-emitting dopants. Host materials and fluorescent, phosphorescent and TADF light-emitting dopants suitable for use in lightemitting layers or units are well-known and commonly used. A light-emitting unit, as previously defined, could also be used for emission. The choice of appropriate materials is not critical and any may be selected based on their performance and emission characteristics.

[0164] Over LEL1 (Layer 1004) is located a hole-blocking layer (HBL; Layer 1005) as needed. Light-emitting layers emit via the formation of excitons which in some cases, are not formed sufficiently fast before holes migrate towards the cathode. The purpose of an HBL is to confine the holes to the LEL to 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. Since it is non-light emitting, it does not contain emitting materials. There may be multiple HBLs present. The choice of appropriate materials is not critical and any may be selected based on their performance. One example of a suitable HBL is SF3-TRZ.

[0165] Over the HBL (Layer 1005) is located a charge generating layer (CGL; Layer 1006). CGLs (sometimes also referred to as connector or intermediate layers) are located between the individual OLED light-emitting units and typically consist of multiple layers. This is because the CGLs are structured so that electrons and holes are generated upon voltage application, and injected to the adjacent organic emissive layers. Hence, the use of a CGL can possibly convert one injected electron to multiple photons, allowing for higher luminance. In particular, it is desirable that a CGL is located between each light-emitting unit within the stack. However, it is not necessary for a light-generating unit to have an adjacent CGL on both sides. The OLED light-generating units on the top and bottom of the stack will generally have only one adjacent CGL. There is typically no need to use a CGL between a light- emitting unit and one of the top or bottom electrodes, although a CGL could be used if desired.

[0166] Many different kinds of CGLs have been proposed and may be used in the OLED stack. For example, see US7728517 and US2007 / 0046189. For the formation of a CGL, an n- p semiconductor heterojunction, which is located at the interface of n-type and p-type layers, is typically needed for the charge generation. Thus, CGLs 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 all been reported. A desirable metal oxide for CGLs is MoOs. In some instances, the n-layer and p-layer may be separated by a thin intermediate layer. Often, the CGL is arranged so that the n-layer is closer to the anode and the p-layer is closer to the cathode.

[0167] One desirable formulation for a CGL has three layers; an electron-transport material doped with a n-dopant (for example, Li), a thin intermediate layer of the same (but undoped) electron-transport material, and a hole-transport material doped with a p-dopant. Another desirable formulation for a CGL would have the same type of doped ETL, with an interlayer of a different electron-transport material and an electron deficient hole-injection material such as HAT-CN. Another desirable formulation for a CGL would have an undoped ETL layer, a layer of Li or Ca, an interlayer of the same or different electron-transport material and an electron deficient hole-injection material or a hole-transport material doped with a p- dopant.

[0168] Suitable electron-transport and hole-injection or transport materials, along with n- dopants and p-dopants suitable for use in CGLs are well-known and commonly used. The materials may be organic or inorganic. The choice of appropriate materials is not critical and any may be selected based on their performance. The thickness of the CGL should desirably be in the range of 200-450 A, although in some examples, a thinner CGL may be in the range of 100-200 A. In many instances, the CGL will have an ETL or HBL on the anode side and an HTL or EBL on its cathode side to help improve charge transport and help separate the charge-generating dopants (if present) from the LEL in the light-emitting units. There may be multiple such layers and may be doped or undoped as desired.

[0169] Over the CGL (Layer 1006), is located a second light-emitting layer or unit (LEL2; Layer 1007) representing the second stack of the OLED device. In Fig. 13, the two LELs (Layers 1004 and 1007) are separated by a CGL (Layer 1006) and so, the OLED stack in Fig. 13 is a “two-stack” (or double-stacked) OLED. There may be one or more HTLs (doped or undoped) between the CGL (Layer 1006) and LEL2 (Layer 1007). LEL2 may emit the same color as LEL1 or a different color.

[0170] Over LEL2 (Layer 1007) is located at least one HBL (Layer 1008) similar to that described as Layer 1005.

[0171] Over the HBL (Layer 1008) is located an electron-transport layer (ETL; Layer 1009). The purpose of the ETL is to manage the transport of electrons from the EIL to the lightemitting layers below. Suitable electron-transport materials are well-known and commonly used. These layers may be mixtures of such materials and may contain dopants to modify their properties. Since it is non-light emitting, it does not contain emitting materials. There may be multiple ETLs present. The choice of appropriate materials is not critical and any may be selected based on their performance. One example of a suitable ETL is TPBI.

[0172] Over the ETL (Layer 1009) is located an electron -injecting layer (EIL; Layer 1010) as needed. The purpose of the EIL is to manage the transport of electrons to the organic layers from the cathode. 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. Since it is non-light emitting, it does not contain emitting materials. There is generally only one EIL present. The choice of appropriate materials is not critical and any may be selected based on their performance. One example of a suitable EIL material is LiF.

[0173] Over the organic layers for light emission (Layers 1001-1010), there is a top electrode 30 which is a cathode. It is desirably composed of a thicker layer of metal or metal alloy such as Al, Ag, Mg / Al, Mg / Ag and the like. The second electrode may be deposited by any known technique. The second electrode may be patterned in non-emissive areas, but generally is deposited uniformly over the emission area. There needs to be contact area (contact pad) that is external to the encapsulation that is electrically connected to the top electrode within the encapsulation for external power supply. Some examples of suitable materials for the top electrode are Al, Al / Mg, Ag / Mg and Ag.

[0174] There may be optional protective or spacing layers (1011) over the top electrode to prevent damage during encapsulation. These may be small molecule organic, polymeric or inorganic materials. Organic materials are preferred.

[0175] Over the reflective cathode and any optional protective layers, if present, is deposited or placed encapsulation 35. At a minimum, the encapsulation should fully cover the lightemitting area on the top and sides and is in direct contact with the substrate. The encapsulation should be impervious to air and water penetration. It may be transparent or opaque. It should not be electrically conductive. It may be formed in-situ or added as a separate pre-formed sheet along with provisions for sealing the side edges.

[0176] An example of in-situ formation would be thin-film encapsulation. Thin-film encapsulation involves the deposition of multiple layers with alternative layers of inorganic materials and polymeric layers until the desired degree of protection is achieved. Formulations and methods to form thin-film encapsulation are well known and any can be used as desired.

[0177] Alternatively, encapsulation may be provided using a pre-formed sheet or cover slip which is attached over at least a sealing area and enclosed area. The pre-formed sheet may be rigid or flexible. It could be made of glass (including flexible glass), metal or organic / inorganic barrier layers. It should have a thermal expansion coefficient that is close to the substrate to achieve a more robust connection. Pre-formed encapsulation sheets may need to be attached over the sealing area using air and water proof adhesives such as silicon or epoxy adhesives or by thermal means such as ultrasonic welding or glass frit welding, which may require additional sealants such as solder or glass frit. The side and bottom edges of the cover slip can be specially designed to have better fit to the sealing area or promote a better seal. The cover slip and sealing area may be designed together so that they fit or lock partially in place before the seal is formed. Moreover, the cover slip may be pretreated to promote better adhesion to the sealing area.

[0178] For some applications, an increased degree of encapsulation is necessary. This can be accomplished by providing an additional metal foil encapsulation (Layer 1013) which is attached over the encapsulation 35 by a pressure-sensitive adhesive (Layer 1012). Not only does the use of a metal foil provide robust encapsulation, it also acts as a heat sink to prevent excessive heating which is deleterious to OLED devices.

[0179] For many applications, a single stack OLED device can provide sufficient emission for the intended purpose. For some applications, more luminance is required than can be provided by a single OLED stack. In such cases, two (as shown for Fig. 13) or more stacks will be required. Generally speaking, adding an OLED stack (i.e., two units instead of one) will double the luminance produced, although the power required is also doubled. Three- stack OLEDs will produce 3X the luminance but require 3X the power and so forth. In the segmented OLED device of the invention, as many stacks necessary to produce the desired amount of luminance can be added; the only limitation being the increased voltage necessary to drive the device. Desirably, there are at least two stacks and as many as six stacks in the segmented OLED device. Suitable formulations and materials for such OLED stacks are well known; for example, US7273663, US9379346, US9741957, US 9281487, US2020 / 0013978 and US11031577 all describe OLED stacks with multiple stacks of light-emitting OLED units, each separated by intermediate connection layers or charge generation layers. Springer et al, Optics Express, 24 (24), 28131 (2016) reports OLED stacks with 2- and 3- lightemitting units, where each unit has a different color. OLED stacks of up to six light-emitting units have been reported (Spindler et al, “High Brightness OLED Lighting”, SID Display Week 2016, San Francisco CA, May 23-27, 2016).

[0180] Another method of increasing luminance, particularly when single color emission is desired, from an OLED is to incorporate the microcavity effect. To form a microcavity, one electrode is reflective and the other is semi-transparent so light is reflected internally. Depending on the distance between the two electrodes, interference will occur and some wavelengths of light will be eliminated or reduced, while other wavelengths will be enhanced. The microcavity effect can be used for the OLED segments of the OLED device.

[0181] While the various individual LELs or units within the segmented OLED device are not limited to providing the same color, some applications require monochromatic emission. For example, for many automotive tail-light applications, all LELs or units should produce red light. It should be noted that although different LELs or units all might produce the same color of light; it is not necessary that all have identical emission spectrums; some may have a different proportion of certain wavelengths from another (i.e., one unit produces a spectrum with more short red wavelengths while another produces more longer red wavelengths). For arrays that are not monochromatic, the organic layers for light emission above the appropriate bottom electrode may not be in common with the others. In such cases, the light emission layers over each electrode segment are separated by a pixel definition layer within the gap between electrode segments. Alternatively, all OLED segments can emit white or multimodal light and color filters can be used to create the desired color of emission of each particular segment.

[0182] One method for making a bottom-emitting segmented OLED device with an array of OLED segments with reduced noticeability of the power feeds located in the emission light path (such as 200) would comprise, in order, the steps of:

[0183] 1) Patterning electrically conductive power feeds such that there will be one dedicated power feed for each OLED segment along with any necessary extension lines that are associated with a power feed, but which are not in electrical contact, so that the power feed (and associated extension line, if present) form a line that appears to be continuous and forms part of a visible pattern of evenly spaced parallel lines of constant width on a transparent substrate;

[0184] 2) Depositing a non-electrically conductive insulating layer over the power feeds and the extension lines including any lateral spaces between the power feeds and the extension lines and patterning vias through the insulating layer above the power feeds;

[0185] 3) Patterning bottom electrode segments over the insulating layer;

[0186] 4) Depositing organic layers for light emission over the electrode segments;

[0187] 5) Depositing a top electrode over the organic layers; and

[0188] 6) Forming encapsulation over the top electrode.

[0189] Another method for making a bottom-emitting segmented OLED device with an array of OLED segments with reduced noticeability of the power feeds located in the emission light path would comprise, in order, the steps of:

[0190] 1) Patterning bottom electrodes for the OLED segments on a transparent substrate;

[0191] 2) Patterning a non-electrically conductive insulating layer over the bottom electrode segments;

[0192] 3) Forming a via in the insulating layer over a bottom electrode segment;

[0193] 4) Patterning over the insulating layer a dedicated power feed for each bottom electrode so that it is electrically connected through a via, along with any necessary extension lines that are associated with a power feed, but which are not in electrical contact with the power feed, so that the power feed (and associated extension line, if present) forms a line that appears to be continuous and forms part of a visible pattern of evenly spaced parallel lines of constant width;

[0194] 5) Patterning a non-electrically conductive insulating layer over the power feeds and the extension lines;

[0195] 6) Depositing organic layers for light emission over the electrode segments and insulated power feeds (and associated extension line, if present);

[0196] 7) Depositing a top electrode over the organic layers; and

[0197] 8) Forming encapsulation over the top electrode.

[0198] Some useful variations in both of these methods include: the step of patterning the non-electrically conductive insulating layer over the bottom electrode segments; the step of patterning the power feeds and extension lines (if present) includes adding extra pattern lines as part of the visible pattern, the step of patterning the bottom electrode segments includes forming a non-electrically conductive pixel definition layer between the segments; the step of forming vias for connection between an individual power feed and a single bottom electrode; and the step of adding a metallic heat sink over the encapsulation.

[0199] Some desirable performance characteristics for the segmented OLED device with reduced noticeability of the power feeds include: current density for 2000 cd / m2: 13 mA / cm2(2-stack), 4.3 mA / cm2(6-stack); current density for 5000 cd / m2: 32 mA / cm2(2-stack), 9 mA / cm2(6-stack); current density for 10000 cd / m2: 25 mA / cm2(6-stack); and current density for 20000 cd / m2: 50 mA / cm2(6-stack).

[0200] The above description describes a number of different embodiments. Individual features from any of the embodiments may be combined without limitation.

[0201] In the above description, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments which may be practiced. These embodiments are described in detail to enable those skilled in the art to practice the invention, and it is to 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 present invention. The description of any example embodiments is, therefore, not to be taken in a limiting sense. Although the present invention has been described for the purpose of illustration, it is understood that such detail is solely for that purpose and variations can be made by those skilled in the art without departing from the spirit and scope of the invention.

[0202] Parts List

[0203] SI, S2, S3... OLED Segments

[0204] Pl, P2, P3. .. Individual Power Feed for Segmented Electrode

[0205] P9a, P9b External contact pads for Power feed P9

[0206] VI, V2, V3.. Vias from Power Feed to Electrode Segment

[0207] 5 Gap between OLED Segments

[0208] 10 Transparent Support

[0209] 15 Electrical Insulating Layer

[0210] 17 Insulating Layer / Pixel Definition Layer

[0211] 20 Bottom OLED Electrode Segment

[0212] 25 Organic Layers for Light Emission

[0213] 30 Top OLED electrode

[0214] 35 Encapsulation

[0215] 50, 51 Evenly spaced visible lines of a pattern 50a, 56, 58, 60a, 62a Extension Line

[0216] 50b, 54, 60b, 62b Extra Pattern Line d Distance between Visible Lines

[0217] 100 - 900 Segmented OLED Arrays

[0218] 1000 OLED Device

[0219] 1001 HIL

[0220] 1002 HTL

[0221] 1003 EBL

[0222] 1004 LEL1

[0223] 1005 HBL

[0224] 1006 CGL

[0225] 1007 LEL2

[0226] 1008 HBL

[0227] 1009 ETL

[0228] 1010 EIL

[0229] 1011 Optional Protection Layer

[0230] 1012 Pressure Sensitive Adhesive

[0231] 1013 Metal Foil Encapsulation / Heat Sink

Claims

CLAIMS1. An OLED device comprising an array of bottom-emitting OLED segments (SI, S2, S3,. . .) arranged on a common transparent substrate (10), each individual OLED segment being separated by a non-emitting gap (5); wherein each OLED segment (SI, S2, S3. . .) has an active emitting area defined by a transparent bottom electrode segment (20), a top electrode (30) and organic layers for light emission (25) between the top electrode (30) and bottom electrode segment (20), where each segmented bottom electrode (20) is electrically connected to an individual power feed (Pl, P2, P3,...); so that for at least a first OLED segment (SI), there is at least one individual power feed for another OLED segment, which is not in electrical contact with the first OLED segment (SI), arranged within the emission light path of the first OLED segment (SI); wherein the power feed for another OLED segment located within the emission light path of the first OLED segment (SI) is included as at least part of a visible pattern of evenly spaced parallel lines (50, 51) of constant width that appear to continuously extend across the active areas of the first (SI) and at least one other OLED segment.

2. The OLED device of claim 1 wherein at least one of the parallel lines of the visible pattern includes a first line section which is an individual power feed (Pl, P2, P3,. . .) and a second line section that is an extension line (50a, 56, 58, 60a, 62a), which is electrically isolated from the power feed (Pl, P2, P3,. . .) in the first line section, so that the first and second line sections together form a straight line that visibly appears to be continuous.

3. The OLED device of claim 2 wherein the extension line (50a, 56, 58, 60a, 62a) of the visible pattern is located in the same plane above the substrate as the power feed (Pl, P2, P3,. . .), has the same composition as the power feed (Pl, P2, P3,. . .), and has the same width as the power feed (Pl, P2, P3,...).

4. The OLED device of claim 3 wherein at least part of the visible pattern includes at least one extra pattern line (50b, 54, 60b, 62b) which is separate from and electrically isolated from any of the individual power feeds (Pl, P2, P3,. . .).

5. The OLED device of claim 4 wherein all of the individual power feeds (Pl, P2, extension lines (50a, 56, 58, 60a, 62a) and extra pattern lines (50b, 54, 60b, 62b) within the array are opaque to light.

6. The OLED device of claim 5 where the individual power feeds (Pl, P2, P3,. . .) comprise layers of chromium and aluminum.

7. The OLED device of any of claims 1-6 where at least two of the evenly spaced parallel lines (50, 51) of the visible pattern extend from one edge of the light-emitting area of the array to the opposite edge so that the lines of the pattern (50, 51) are visible in the emission of all OLED segments along that line.

8. The OLED device of any of claims 1-6 where there are two or more overlapping visible patterns of evenly spaced parallel lines of constant width (50, 51), wherein the evenly spaced parallel lines of each pattern (50, 51) are set at an angle to each other.

9. The OLED device of any of claims 1-6 wherein the visible pattern of evenly spaced parallel lines of constant width is superimposed over at least 70% of the total emitting area of the array.

10. The OLED device of claim 9 wherein there is one primary visible pattern of evenly spaced parallel lines of constant width (50) and one or more secondary visible patterns of evenly spaced parallel lines of constant width (51), wherein the primary pattern is superimposed over at least 51% of the total emitting area of the array.

11. The OLED device of claim 10 wherein the primary pattern is located in the center of the array and all of the secondary pattern(s) are located within 20% of the total distance of the light-emitting area of the array to the nearest edge.

12. The OLED device of any of claims 1-6 where there are power feeds (Pl, P2, P3,. . .) for at least one OLED segment (SI, S2, S3. . .) located within the non-emitting gap (5).

13. The OLED device of claim 12 wherein at least one of the parallel lines (50, 51) of the visible pattern is located within the non-emitting gap (5), the line within the non-emitting gap(5) includes a first section which is an individual power feed (Pl, P2, P3,. . .) and a second section that is an extension line (50a, 56, 58a, 60a, 62a), which is electrically isolated from the power feed in the first section, so that the first and second sections together form a straight line that visibly appears to be continuous.

14. The OLED device of any of claims 1-6 where the parallel lines are spaced apart by a distance (d) in a range of 0.05-10 mm.

15. The OLED device of any of the claims 1-6 where the width of the parallel lines is in the range of 0.005-1 mm.

Images