Segmented OLED with electrostatic discharge protection

Abstract

A segmented bottom emission OLED device comprising an array of a plurality of OLED segments arranged on a common transparent substrate, where the array forms an emission area, where each segment is separated by a non-emission gap; wherein each OLED segment is defined by a transparent bottom electrode segment, an organic layer for light emission, and a top electrode; wherein a transparent insulating layer closer to the bottom electrode section and a transparent conductive layer closer to the substrate exist between the bottom electrode and the substrate in at least one OLED section.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] Please refer to the jointly filed and jointly assigned PCT application PCT / US2022 / 029409 entitled “SEGMENTED OLED” under attorney docket OLWK-0024-PCT, which claims the benefit of U.S. Provisional Application No. 63 / 192,942 filed on May 25, 2021 under attorney docket OLWK-0024-USP. Background Art

[0003] Electrostatic discharge (ESD) is the sudden and instantaneous flow of electric current between two charged objects. ESD can cause significant detrimental effects in industry, including the failure of electronic components. These can suffer permanent damage when subjected to high voltages. For OLED devices, its sensitivity to ESD can depend on the type of organic material used for light emission; some materials and formulations may be more sensitive than others. Sensitive electronic components need to be protected during and after manufacturing, during shipping / handling and device assembly, and in the finished device. ESD tends to be a particular problem when the device is in the "OFF" or non-operating state.

[0004] Some common methods of providing ESD protection in OLED devices include: ESD protection as part of the driving circuit (e.g., see US10692957B2); adding peripheral conductive structures (e.g., see US7944140B2); adding separate ESD protection circuits (e.g., see US9246121B2); and using capacitors or transistors outside the emission area (e.g., see US6046547A). Such methods may or may not be useful when the device is in the "OFF" state. Due to the dielectric properties of electronic components and assemblies, electrostatic charging cannot be completely prevented during the handling of the device. An effective method to prevent ESD is to use a material that is not very conductive but will slowly conduct or release the static charge. Such dissipative materials typically have a resistance of less than 10 12 The resistivity value is in ohm-meters. Such a material is able to conduct electricity, but only very slowly. Any accumulated static charge can then dissipate without a sudden discharge that could damage the internal structure of the electronic device.

[0005] Not all electronic devices are equally sensitive to ESD damage. This may depend on the application or environment involved. For example, an electronic component that is assembled into a sealed module under controlled conditions may not be susceptible to ESD damage, while the same electronic component may be sensitive if handled manually. In addition, there are ESD levels; an electronic component may be robust to lower levels of ESD, but may be sensitive at higher levels. For some applications (i.e. automotive applications), the device may be exposed to ESD in the range of 8kV or less. However, the ESD voltage may be as high as 30kV.

[0006] One way to prevent or suppress ESD is to incorporate capacitors in the device. See, for example, https: / / www.vishay.com / docs / 45257 / vishayautomlccsesdprotect.pdf. Typically, capacitors are integral to or located near ESD sensitive components to absorb and then balance or dissipate unwanted voltage spikes.

[0007] OLEDs are capacitors consisting of two area electrodes separated by a resistive organic layer. Like any capacitor, their intrinsic capacitance depends on the overlap area between the two electrodes, the distance between the electrodes, the resistivity of the organic layer and the type of material used, among other factors.

[0008] Ideally, if the intrinsic capacitance of an OLED is high enough, it should be able to dissipate any ESD without damaging the OLED or its associated circuitry. However, since the intrinsic capacitance depends on the area size of the OLED and other factors, large-size OLED devices (e.g., OLEDs for general lighting applications, which are typically larger than 25 cm in area) are not ideal. 2 ) may have sufficiently high intrinsic capacitance to be relatively insensitive to ESD damage. ESD protection may not be required. Very small OLED devices (e.g., pixels in active and passive matrix OLED displays, which are typically about 200-300 μm in area at most) may have sufficiently high intrinsic capacitance to be relatively insensitive to ESD damage. ESD protection may not be required. 2 ) have relatively low inherent capacitance and can be very sensitive to ESD damage. However, because OLED displays already use complex control and drive circuits, it is relatively simple to add external ESD protection as part of the circuit.

[0009] OLED devices sized between these extremes can be susceptible to ESD damage because their intrinsic capacitance is not large enough to dissipate ESD effectively, and often have simple (and typically off-substrate) control circuitry for which adding additional ESD protection circuitry would be problematic from a cost and ease of manufacturing perspective. Typically, OLED devices with an area less than 1 cm2 are used without expensive or complex external protection mechanisms.2 , and especially 0.5 cm 2 OLEDs that are smaller than 100nm or smaller may be particularly susceptible to ESD damage.

[0010] For some applications, multiple independently controlled individual OLED devices of this medium size range can be mounted on a single substrate to provide a "tile" device. In a "tile" OLED device, each individual OLED light source is pre- and independently manufactured (except for electrical connections), including its own substrate, and mounted side by side or in an array. The manufacture of "tile" devices can be expensive due to the complex assembly required.

[0011] For other applications, multiple independently controlled individual OLED devices can be fabricated directly on a single common substrate to provide a "segmented" OLED device. In particular, each individual OLED segment of a segmented OLED is all fabricated directly on the same substrate, side by side or in an array. There are non-emissive gaps or spaces between the individual segments. Such a segmented OLED light source can provide manufacturing and cost advantages because many layers can be shared across all the individual units and no separate OLED panels need to be handled or installed.

[0012] Segmented OLED devices can provide variable general lighting (i.e., by powering individual segments according to the desired total amount of light) or low-resolution communication devices (i.e., by powering the segments in a pattern). However, in segmented OLED devices, the individual OLED segments are significantly larger than the OLED pixels in high-resolution displays. The minimum size of an OLED segment is at least 0.025 cm 2 , and more preferably 0.05 cm 2 or larger. This is by design, because for applications that do not require high resolution, a larger OLED will produce more light. In addition, while OLED pixels in displays require complex on-substrate drive circuits to operate at high frequencies, segmented OLED devices operating at low frequencies can use simpler off-substrate drive circuits, which reduces manufacturing cost and complexity.

[0013] Segmented OLED devices are particularly suitable for automotive exterior lighting applications (eg, taillights) because, unlike LED devices, they do not require additional reflectors, light guides, or additional optics to generate a uniform surface light. For example, see M. Kruppa et al., Information Display 4 / 19, pp. 14-18 (2019); H. Bechert et al., “Flexible and highly segmented OLED for automotive applications”, Proc. SPIE 10687, Organic Electronics and Photonics: Fundamentals and Devices, 106870Q (May 21, 2018); M. Kondakova et al., 8-1: Invited Paper: Development of High-Temperature Stable Red OLEDs for Automotive Lighting, SID Symposium Digest of Technical Papers, 51: 83-85 (2020); C. May, “Flexible OLED lighting and signage for automotive application”, 2021 28th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD), 2021, pp. 42-45; and D. Q. Chowdhury et al., “Application of OLED for Automotive Lighting”, 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD), 2019, pp. 1-3.

[0014] Applications such as automotive taillights often require a certain degree of visibility from the sides as well as directly from the rear, so taillight assemblies often have complex designs that mix curved and relatively flat surfaces. Segmented OLED devices can be fabricated on flexible substrates, which simplifies design considerations in non-planar taillight assemblies. However, automotive taillight assemblies are an integral part of the overall appearance of the vehicle and must provide a sleek and compliant design and appearance.

[0015] In general, OLED devices are formed on a substrate and can be top-emitting (light is emitted from a surface opposite the substrate) or bottom-emitting (light is emitted through a transparent substrate). In order to create individually controlled OLED segments, at least one of the electrodes must be segmented; that is, the electrodes of one OLED segment are electrically separated from corresponding electrodes in a different OLED segment. In this way, emission from each OLED segment can be individually controlled by a single unique power feed (also called a bus line, bus bar, metal trace, conductive trace, lead, or current trace) to the electrode segment.

[0016] It is desirable to form the power leads directly on the substrate before any organic OLED layers are applied. This is because they must be patterned separately because there is at least one power lead for each segment. A cost-effective way to manufacture the power leads is to use photolithography processes and techniques that can form very fine conductive structure patterns. However, when using photolithography on organic OLED layers, it is generally incompatible. It is possible to use fine metal mask processes and techniques to create power lines, even above the organic OLED layers, but this will be more expensive and more prone to defects during manufacturing. The conductive structures created by the mask process are also significantly larger than those that can be made using photolithography.

[0017] For bottom-emitting OLEDs with bottom segmented electrodes, the individual power feeders connected to each electrode segment are desirably located at the same (horizontal) level as the electrode segments or below (between the electrode segments and the substrate). However, the choice of any location is a trade-off. The power feeders can be located laterally adjacent to the electrode segments (separated by insulating material to maintain non-contact), but this may undesirably increase the space between the electrode segments (due to the number of individual power feeders required) and may easily short-circuit the power feeder of one electrode segment to the power feeder of a second electrode segment. The power feeders can be located below the electrode segments, but must be electrically isolated from the overlying electrode segments to avoid short circuits. This may complicate manufacturing because additional layers are required. If the power feeders are located in the emission path, they may be visible, which would be undesirable.

[0018] Although both top-emitting and bottom-emitting OLEDs are suitable for automotive applications, bottom-emitting OLEDs are preferred for at least two reasons. First, a sturdy encapsulation is necessary for exterior applications. This is more difficult to achieve with a transparent encapsulation, especially for flexible OLEDs, which is required for top-emitting OLEDs. Since the encapsulation on the non-emitting side does not need to be transparent, a very sturdy encapsulation can be used for bottom-emitting OLEDs. Second, the OLED will be located in a confined space, where heat accumulation may be a problem. Bottom-emitting OLEDs allow the heat sink to be located on the back. For top-emitting OLEDs, the heat sink is located on the opposite side of the substrate, which reduces the heat transfer rate and therefore the cooling efficiency is not high.

[0019] However, since at least some of the OLED segments in a segmented device may be small enough to be sensitive to ESD damage, where such small OLED segments may have only simple direct electrical connections to control circuitry external to the substrate, it is desirable to provide ESD protection that is simple to manufacture and low cost. The ESD protection should be on the substrate and passive (i.e., not requiring a power source) because protection is required when the OLED device is not operating or powered ("OFF") or even not attached to any other components.

[0020] H.Bechert et al., "Thin-Film Electrostatic Discharge Protection for Highly Segmented OLEDs in Automotive Applications", Adv.Mater.Technol., 4 , 1800696 (2019), and a similar communication article in Adv. Mater. Technol., describe a top-emitting segmented OLED device in which electrostatic protection is provided by a passive capacitor on a substrate with a continuous and opaque conductive layer (composed of Cr / Al / Cr, opaque) as one electrode, an insulating layer (composed of Al2O3 or ZrO2), and an anode segment (composition undisclosed) as the opposite electrode. The continuous conductive layer is located below all electrode segments and is not connected to anything. Because the conductive layer is composed of a conductive metal, it is not suitable for bottom-emitting devices. In addition, the opaque conductive layer is located below all electrode segments. Such an arrangement may also be prone to short circuits between electrode segments due to manufacturing defects, especially due to pinholes in the insulating layer. The reference does not disclose the location of the power feed lines, which is an important consideration.

[0021] US8445910 describes a bottom emission OLED display, in which the drive circuit for each pixel includes a storage capacitor located in the emission path, and the storage capacitor has a structure of a transparent anode / insulating layer / transparent conductive layer. The reference describes the transparent conductive layer as being patterned as a wiring line or only under the anode. However, if the transparent conductive layer (the lower electrode of the capacitor) is part of the wiring line, such a device will not operate because the transparent capacitor is part of the drive circuit of the pixel, and therefore, the transparent conductive layer cannot be connected to any other pixel in the display. US10825883B2 also describes a bottom emission OLED display, in which the drive circuit for each pixel includes a storage capacitor, and the storage capacitor has a structure of a transparent anode / insulating layer / transparent conductive layer. The reference points out that the transparent storage capacitor also has a "holding capacitor", which can stabilize the write voltage of the storage capacitor if it is greater than the storage capacitor used for OLED operation. Other references describing bottom-emitting OLED displays in which the drive circuit for each pixel includes a storage capacitor in the emission path having a transparent anode / insulating layer / transparent conductive layer structure include: US10446633B2, CN109244107B, US9601553B2, US20150214249A1, US9385171B2, CN109166895B, CN109119440B, and US8102476B2. However, in all of the above references, the transparent capacitor is part of the drive circuit and is the same size as the pixel, which may not increase the overall capacitance enough to prevent ESD damage.

[0022] US8941143 and US9487878 describe segmented OLEDs with conductive tracks extending through the device and in contact with hole injection tracks. US9487878 also describes using conductive tracks with varying thickness (height) or width from the outer segment to the inner segment to solve the IR drop problem. A similar concept of having a conductive layer with varying thickness to solve the IR drop is disclosed in US9159945.

[0023] US10068958 describes a segmented OLED in which conductive tracks are located between the segments.

[0024] US9627643 describes an OLED with conductive tracks, wherein the OLED electrodes and the conductive tracks are all transparent.

[0025] There is a need to protect a bottom emitting segmented OLED device having at least one small OLED segment from ESD damage, wherein the protection is provided even when the device is not operating. Summary of the invention

[0026] A segmented bottom-emitting OLED device comprises an array of multiple OLED segments arranged on a common transparent substrate, wherein the array forms an emission area, wherein each OLED segment is separated by a non-emitting gap; wherein each OLED segment is defined by a transparent bottom electrode segment, an organic layer for light emission, and a top electrode; wherein between the bottom electrode segment in at least one OLED segment and the substrate, there is a transparent insulating layer closer to the bottom electrode segment and a transparent conductive layer closer to the substrate, so that the overlapping area between the bottom electrode and the conductive layer forms an associated passive capacitor structure, wherein 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 layer is the lower electrode of the passive capacitor structure.

[0027] The above OLED device, wherein the conductive layer is patterned. The conductive layer may be patterned into two or more parts electrically isolated from each other.

[0028] Any of the above OLED devices, wherein in at least one OLED segment, the overlap area between the conductive layer portion(s) and the bottom electrode segment increases the total capacitance of the OLED segment by at least 0.2 nanofarads (nF). Any of the above OLED devices, wherein in at least one OLED segment, the overlap area between the conductive layer portion(s) and the bottom electrode segment is 30% or more of the area of ​​the bottom electrode segment.

[0029] Any of the above OLED devices, wherein the bottom electrode segments of at least one different OLED segment in the array have no overlap with the conductive layer portion, except for those OLED segments having associated passive capacitor structures, such that no passive capacitor structure is associated with the at least one different OLED segment. The size of the at least one different OLED segment without a passive capacitor structure may be 1.0 cm 2 or larger.

[0030] Any of the above OLED devices, wherein the bottom electrode of each OLED segment in the array is electrically connected to a dedicated power feed line that controls light emission, wherein the power feed lines are arranged laterally between the bottom electrode segments and are electrically isolated from other power feed lines and any individual electrode segments.

[0031] Any of the above OLED devices, wherein the bottom electrode segments of each OLED segment in the array are electrically connected to a single power feeder that controls light emission, wherein the power feeder is arranged laterally between the conductive layer portions and is electrically isolated from other power feeders and conductive layer portions, and from the bottom electrode segments of any individual OLED segment by an insulating layer. The dedicated power feeder can be connected to the corresponding bottom electrode segment through a through hole in the insulating layer. Any of these OLED devices, wherein at least one of the power feeders is arranged to pass under at least one bottom electrode segment in the emission region of the individual OLED segment.

[0032] Any of the above OLED devices, wherein there are a plurality of power feed lines beneath a bottom electrode segment of at least one individual OLED segment, such that the overlap between all of the power feed lines and the bottom electrode of the individual OLED segment forms an associated passive capacitor structure, wherein the bottom electrode segment is an upper electrode of the passive capacitor structure, the insulating layer is a dielectric of the passive capacitor structure, and the plurality of power feed lines together are a lower electrode of the passive capacitor structure. In at least one individual OLED segment, the overlap area between the plurality of power feed lines and the bottom electrode segment in the associated passive capacitor structure increases the total capacitance of the individual OLED segment by at least 0.2 nF, or in the associated passive capacitor structure of the individual OLED segment, the total overlap between the power feed lines and the total area of ​​the overlying bottom electrode is 30% or more of the area of ​​the bottom electrode segment.

[0033] The bottom emitting segmented OLED device as described provides a transparent passive capacitor structure on the substrate located within the emission path of the OLED segment, which has sufficient capacitance, combined with the inherent capacitance of the associated OLED segment, to provide protection against electrostatic discharge. This not only provides ESD protection in the unpowered state, but also placing the passive capacitor structure directly under the segment electrode maximizes the total possible emission area of ​​the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1A is a top view of an innovative segmented OLED device 100 having five segments with a conductive layer that is the lower electrode of a passive capacitor located below all OLED segments. Power feeds are located on the sides of the electrode segments. Figure 1B is a cross-sectional view of 100. Figure 1C A circuit diagram of 100 is shown.

[0035] Figure 2A is a top view of an innovative segmented OLED device 200 having five segments with a conductive layer that is the lower electrode of a passive capacitor located under some of the OLED segments. Power feeds are located on the sides of the electrode segments. Figure 2B is a cross-sectional view of 200.

[0036] Figure 3A is a top view of an innovative segmented OLED device 300 having five segments with a conductive layer that is the lower electrode of a passive capacitor and partially overlaps some of the OLED segments. Power feeds are located on the sides of the electrode segments. Figure 3B is a cross-sectional view of 300.

[0037] Figure 4A is a top view of an innovative segmented OLED device 400 having five segments with a conductive layer that is the lower electrode of a passive capacitor and is located below some of the OLED segments along with power feed lines. Figure 4B is a cross-sectional view of 400.

[0038] Figure 5A is a top view of an innovative segmented OLED device 500 having seven segments, with a conductive layer being the lower electrode of a passive capacitor and being located under some of the OLED segments along with power feeds, some of which pass under the segment electrodes without electrical contact. Figure 5B is a cross-sectional view of 500.

[0039] Fig. 6A is a partial top view along one side of a segmented OLED device 600, wherein a plurality of power feed lines pass under the segment electrodes without electrical contact. Figure 6B It is a partial cross section of 600.

[0040] Figure 7 A schematic cross-sectional view of a dual stack OLED formulation 1000 is shown.

[0041] Figure 8 A test circuit for determining ESD sensitivity is shown.

[0042] The figures are not to scale. DETAILED DESCRIPTION

[0043] For the purposes of this disclosure, the terms "above" or "on top" mean that the structure in question is located above another structure, i.e., on the side opposite to the substrate. "Topmost" or "upper" refers to the side or surface farthest from the substrate, while "lower", "lowermost", "below", "underneath" or "bottom" refers to the side or surface closest to the substrate. Unless otherwise specified, "above" should be interpreted as two structures can be in direct contact, or there can be intermediate layers between them. "Layer" should be understood as a layer having two sides or surfaces (topmost and bottommost), and there can be multiple layers, not limited to a single layer. "LEL" always refers to a single light emitting layer. "Unit" generally indicates the minimum layer that can be considered to act as a single light source; a unit can be equivalent to a single LEL, can contain one LEL associated with other non-light emitting layers, or can have multiple LELs with or without additional layers. A light emitting unit is a group of one or more LELs that are separated from another light emitting unit by a charge generation layer (CGL). Therefore, if an OLED device has no CGL, then it has only one light emitting unit, even though it may have multiple LELs. Such a device is often referred to as a "single stack" device. If an OLED device has two light emitting units separated by a CGL, then it can be referred to as a "dual stack" device. Stacked OLEDs can have multiple units or a combination of units and LELs that together contribute to the total emission.

[0044] R or "red" indicates a layer or unit that emits primarily red light (>600nm, desirably in the range of 620-660nm), G indicates a layer or unit that emits primarily green light (500-600nm, desirably in the range of 540-565nm), and B indicates a layer or unit that emits primarily blue light (<500nm, desirably in the range of 440-485nm). It is important to note that the R, G, and B layers can produce some degree of light outside the indicated ranges, but the amount is always less than the primary colors. Y (yellow) indicates a layer or unit that emits a large amount of both R and G light, but a much smaller amount of B light. Unless otherwise noted, wavelengths are expressed in vacuum values ​​rather than in situ values.

[0045] The OLED light emitting element of the present invention can be a single LEL, a single stack OLED, a double stack OLED, or even three or more OLED stacks, which can emit a single color or multiple colors. If a monochromatic light output is desired or the color temperature of the light output needs to be adjusted or modified, a color filter can be used to eliminate any unwanted wavelengths.

[0046] An OLED light emitting LEL or unit can produce a single "color" of light (i.e., R, G, B, a combination of two primary colors (such as Y or cyan), or W). An individual OLED light emitting unit can have a single light emitting layer, or can have more than one light emitting layer (directly adjacent to each other or separated from each other by intermediate layers). Individual light emitting units can also contain various non-emitting layers, such as hole transport layers, electron transport layers, blocking layers, and other layers known in the art to provide desired effects, such as facilitating emission and managing charge transfer across the light emitting unit. Light of a single color can be generated within an OLED unit by a single layer or multiple layers having one or more emitters of the same color, each layer having the same or different emitters whose primary emission falls 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 light and G light. In this case, yellow is considered a single color.

[0047] A stacked OLED device can produce a single color of light or more than one color of light (multi-mode). For example, a multi-mode OLED produces white light with approximately equal amounts of R, G, and B light. Typically, this would correspond to a CIE 90 of approximately 0.33, 0.33. x 、CIE y White light, even if it does not contain equal amounts of R, G, B light, can generally be produced in an OLED 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 will have a CIE value of approximately 0.6-0.7, 0.2-0.35 x 、CIE y The OLED of the present invention can utilize the microcavity effect to increase the emission of desired color light.

[0048] For specific applications, such as automotive taillights used to signal braking, stopping, turning, and other functions, the light output of the OLED used should be selected to meet all government regulations and SAE or industry standards applicable to the use, especially in terms of color and brightness. In addition, the size and dimensions of the segmented OLED device should be selected to meet all appropriate government regulations and industry standards applicable to the specific use. For such taillight applications, the preferred emission color is red.

[0049] A segmented OLED device consists of multiple individual OLED segments on a common substrate and can have any shape as desired. It can be completely flat or planar, can have multiple planes that are angled to each other, can be completely curved, or can have a mixture of flat, angled or curved surfaces. The segmented OLED device is often mounted in a portion of a housing or module, along with any necessary external power connections and control elements to supply signals or power to the individual segments. The housing or module typically has a transparent portion, which allows light from the OLED device to escape and also provides protection from the external environment. The housing or module may also have an internal reflector or light guide to help guide light emission as desired. The entire housing or module containing the segmented OLED device may be sealed.

[0050] 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 (power feeder) 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 simultaneously to provide uniform light emission (except for the gaps between segments). The light emission across all segments can be constant, dim as a whole, brighten as a whole, or flash on / off. Alternatively, a segmented OLED device can have each segment activated individually and independently in a certain pattern. The pattern may involve some segments being fully turned on, some segments being at intermediate brightness levels, and some segments being turned off. The pattern can remain constant over a period of time, or can be moving, where individual segments are activated on / off in some time-based or position-based sequence. Since segmented OLED devices are not high-resolution displays, and are typically meant to be viewed from a considerable distance, individual OLED segments are significantly larger than individual pixels in high-resolution displays (which typically have a resolution of much less than 0.1 mm). 2 Desirably, for a system having a total emission area not exceeding 500 cm 2 For smaller segmented OLED devices, individual OLED segments should have a minimum of 0.025 cm 2 The emission area is preferably at least 0.05 cm 2 For a total emitting area greater than 500cm 2 For larger segmented devices, individual OLED segments should have a size of at least 0.05 cm 2 The emission area is preferably at least 0.5 cm 2 .

[0051] Individual OLED segments can have any shape or area as desired. Generally, in order to minimize the non-emitting space between individual segments, these segments will form a dense array. Desirably, the array is a regular array so that the spacing between the segments is uniform and provides a sleek appearance. In terms of shape, the array can take any overall form and does not have to be square or rectangular, but can also be circular, elliptical, triangular or polygonal. In some designs, some areas of the array are regular with uniform spacing between them, while other parts of the array are irregular. For example, in a square array, the outside of the array can have smaller square segments arranged in a uniform pattern, while the inner area has a single larger star-shaped segment surrounding a large non-emitting area in the center. Similarly, the shape of the individual OLED segments within the array is not limited, but can be square, rectangular, circular, elliptical, triangular or polygonal, or even irregular, as desired.

[0052] Furthermore, the OLED segments within an array need not all be the same shape, but may have a mixture of shapes, such as, for example, interlocking triangles and hexagons. Preferred are dense arrays having only triangles, only parallelograms, or a mixture of triangles and hexagons or triangles and trapezoids. The individual segments may not all be of the same area, and the array may consist 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 segments emitting different colors may be located in a particular pattern within the array. Desirably, the array of segments is asymmetric; that is, contains segments of different sizes, and more desirably, the array contains segments of different sizes and shapes.

[0053] Figure 1A A top view of a segmented OLED device 100 is shown. There are five different OLED segments 1', 2', 3', 4' and 5' as defined by transparent electrode segments 1, 2, 3, 4 and 5. In this example, the area of ​​OLED segment 5' is greater than 1 cm 2 , and the area of ​​segment 1′-4′ is less than 1cm 2. The OLED segments 1′-5′ are arranged in an asymmetric array on top of a transparent substrate 10, where the outer edge of the array represents the emission area 100. On top of the transparent substrate 10 is a uniform transparent conductive layer 20 and a uniform transparent insulating layer 30. Both 20 and 30 are not patterned. On top of the insulating layer 30, there is a power feeder 15 electrically connected to electrode segment 1, a power feeder 25 connected to electrode segment 2, a power feeder 35 connected to electrode segment 3, a power feeder 45 connected to electrode segment 4, and a power feeder 55 connected to electrode segment 5, all of which occupy the same lateral plane. There is an electrically insulating pixel definition layer (PDL) 40 between the electrode segments and between any adjacent power feeders or between any adjacent electrode segments and power feeders. Because the power feeders may not be as thick as the electrode segments, the PDL 40 can also be deposited on the top surface of the power feeders to flatten the top surface of the PDL / electrode segment layer. Except for the contact points between the electrode segments and their designated power feeders, there should be no electrical contact between these electrode segments and any of the power feeders. On the surface of the PDL 40 / electrode segments 1-5 is an organic layer 50 for light emission (not shown in this view) and a common top electrode 60. Above the electrode 60 is an encapsulation layer 70. One end of each power feeder and the top electrode 60 extend outside the encapsulation 70 to form a contact pad for a control circuit that is separately connected to 100. There is a non-emitting gap or space 80 between the OLED segments (and within the emitting area of ​​the array), which typically corresponds to the location of the PDL 40.

[0054] Figure 1B Shown along Figure 1A 1 ′ is a cross-section of a segmented OLED device 100 along line ZZ′. In this view, an organic layer 50 for light emission, a continuous top electrode 60 that is common across all OLED electrode segments 1-5 and extends beyond the package 70 on one side to form an external contact pad for connection to a control circuit. Arrows indicate the direction of light emitted from individual OLED segments 1′-5′. In this embodiment, power feed lines 15, 25, 35, 45 and 55 are shown as being thinner than the electrode segments, and their upper surfaces are covered by PDL 40 to create a flat upper surface across the electrode segments and the PDL located between the electrode segments. Between the electrode segments (e.g., between 3 and 5), PDL 40 provides a non-emitting gap 80.

[0055] The OLED structures (bottom electrode segments (1-5) / organic layer (50) / common top electrode (60)) in OLED segments 1'-5' are each capacitor structures with associated intrinsic capacitance. Since the top electrode 60 is common to all segments, the intrinsic capacitance (C OLED) will depend, among other factors, on the size of the bottom electrode segment. OLED Only the light emitting OLED portion (top electrode to bottom electrode) of the OLED segment will be associated.

[0056] In 100, on the substrate side of the electrode segments 1-5, there is an insulating layer 30 and a conductive layer 20, both of which are continuous and uniform on the upper surface of the transparent substrate 10. Within a single OLED segment, this can form a multi-planar capacitor structure, where there is a top OLED capacitor structure consisting of top electrode / organic layer (dielectric) / bottom electrode segment, and a bottom passive capacitor structure consisting of bottom electrode segment / insulating layer (dielectric) / conductive layer. It is important to note that even though the conductive layer 20 is not directly electrically connected to any part of the overlying OLED structure, it can still serve as the bottom electrode of the passive capacitor structure because the conductive layer is common to other OLED segments. In 100, since the conductive layer 20 is common to all segments, the capacitance (C 无源 ) will depend, among other factors, on the size of the bottom electrode segments of the OLED. In this embodiment, the vertical overlap between the bottom electrode segments and the conductive layer is 100% of the electrode segments.

[0057] In 100, five passive capacitor structures are formed; one for each OLED segment 1'-5', where the conductive layer overlaps the individual electrode segments 1-5. These five passive capacitor structures, connected in parallel with respect to each other, share the same conductive layer 20 (bottom electrode) and insulating layer 30 (dielectric), and differ only in the different OLED electrode segments. Even though a common conductive layer 20 is shared between different OLED segments, the passive capacitor structure of any one OLED segment is based on the overlap between the bottom electrode of the OLED and the portion of the conductive layer that is directly below it. In the OLED segment of the present invention, the OLED (as a capacitor structure) and the passive capacitor structure are directly related to each other because the two structures share the bottom electrode of the OLED. The conductive layer 20 (which is the bottom electrode of the passive capacitor structure) is not directly connected to any circuit.

[0058] Figure 1C A circuit diagram of 100 is shown, wherein the OLED segments are connected to a control circuit 95 via power feeds 15, 25, 35, 45 and 55. During operation, the control circuit can independently activate the OLED segments 1'-5' as desired. In the unpowered state, each of the five OLED segments 1'-5' will be a multi-planar capacitor, wherein one capacitor portion is a capacitor having a separate inherent capacitance C O1′ -C O5′ The OLED structure, and the other capacitor part is a separate capacitor C P1′ -CP5′ The bottom electrode segment (i.e., 1 in OLED segment 1′) serves both as the lower electrode of the OLED structure and as the upper electrode of the passive capacitor structure. The lower electrode of the passive capacitor structure is the conductive layer 20, which is common to the passive capacitor structures in other OLED segments. Within an individual OLED segment, the OLED structure and the associated passive capacitor structure are connected in series, and the capacitance of the OLED segment as a multi-plane capacitor will be equal to C OLED *C 无源 / (C OLED +C 无源 ).

[0059] However, because the lower electrode (conductive layer 20) of the passive capacitor structure in one OLED segment is shared with the passive capacitor structures in other OLED segments, the C in one OLED segment is 无源 is connected in parallel with all other OLED segments that share the same conductive layer. Therefore, the C 无源 is the capacitance of the passive capacitor structure of the individual OLED segment plus the sum of all capacitances of the other OLED segments.

[0060] On a device such as OLED device 100, static charge can be generated and subsequently discharged via several pathways. The charge can come from above or below the device. Charge from above will encounter top electrode 60. Charge from below will pass through substrate 10 and encounter conductive layer 20. In either case, top electrode 60 or conductive layer 20 will spread the static charge across a significant area, and any discharge will occur across many segments of OLED device 100 (i.e., across the parallel array of multi-planar capacitors as described above), and is unlikely to cause damage to the device.

[0061] A more problematic pathway for electrostatic charging and discharging is if an individual bottom electrode becomes charged. This may occur elsewhere in the device and be delivered to the corresponding bottom electrode segment (e.g., 1) by a power feed (e.g., 15). The danger of this pathway is that, without any mitigating factors, the electrostatic charge on a single bottom electrode segment may discharge through a single OLED segment or at most a few adjacent OLED segments, potentially damaging those OLED segments. Therefore, for the purposes of this invention, it will be assumed that any electrostatic charge appears on the bottom electrode segment, and the capacitance of the corresponding OLED segment will be the capacitance available at the bottom electrode: the capacitance (C) across the OLED structure of 1′. OLED ), and the capacitance (C 无源 ). However, the conductive layer 20 is shared with the passive capacitor structures in other OLED segments, so CP1′ Connected in series with a parallel array of other capacitors. Figure 1C In FIG. 1 , this is illustrated by OLED segments 2′ to 5′ connected in a parallel array, which in turn is connected in series to C P1′ .

[0062] In general, for an array of n OLED segments (assuming equal size), the overall total capacitance (C T ) is the capacitance of the associated OLED segment (C OLED ) and the capacitance (C 无源 ), where each of the n-1 OLED segments has a C OLED and C 无源 Multi-plane capacitors in series, as described above. The total effective capacitance (C T ) is determined according to the following formula:

[0063] C T =C OLED +C 无源 x[(n-1) . C OLED / (C 无源 +n . C OLED )]

[0064] Note that as the number of segments increases, the added capacitance due to the passive capacitor structure can be approximated by the value added by a single OLED segment:

[0065] C T ~C OLED +C 无源 (For large n)

[0066] For arrays with different OLED sizes the capacitance will be summed individually, but if n is large enough it will still approximate the value added by a single average OLED segment.

[0067] Because the size of the OLED segments is primarily selected to meet the light emission purposes and requirements of the device, they may not have sufficient inherent capacitance to protect against ESD damage; this capacitance can be increased within the array by adding passive capacitor structures across the OLED segments to form an array of OLED segments, where at least some of the OLED segments are each associated with a passive capacitor structure. The addition of such passive capacitor structures increases the overall capacitance, thereby reducing its susceptibility to ESD damage. Because the overall capacitance of the OLED segments has been increased by the addition of the passive capacitor structure(s), any static charge can be better dissipated, and thus damage to organic layers in the overlying OLED structure can be mitigated.

[0068] In particular, the passive capacitor structure(s) should provide an increase in the total capacitance of the OLED segment relative to the same OLED segment without the passive capacitor structure. The additional capacitance should be sufficient to provide the desired level of protection from ESD damage. The susceptibility of the OLED to ESD damage depends on V LIM , V LIM is the upper voltage limit that is expected to cause damage to the OLED. V LIM is an intrinsic property of the OLED formulation, can vary widely between different OLED formulations, and is independent of the size of the OLED. LIM This can be determined experimentally. Increasing the overall capacitance of the OLED segment will reduce the voltage experienced by the OLED due to electrostatic discharge and thus maintain the voltage experienced by the OLED at V LIM Therefore, it is desirable that the sum capacitance provided by the passive capacitor structure(s) is sufficient to increase the total capacitance of the OLED segment when added to the inherent capacitance of the OLED portion of the segment so that the voltage experienced during an ESD event is maintained at V LIM the following.

[0069] The area (size) of the individual OLED segments is critical in determining susceptibility to ESD damage. Emission area greater than 1.0 cm 2 Larger segments, 1.0 cm or greater, generally have sufficient inherent capacitance to dissipate ESD without damage. 2 or smaller, and especially smaller than 0.5 cm 2 OLED segments with a size of 1 cm may be susceptible to ESD damage because their intrinsic capacitance is not that high. Therefore, in a segmented OLED device with segments of different sizes, it may not be necessary to provide additional ESD protection for larger segments by adding associated passive capacitor structures. For example, OLED segment 5′ in 100 has a relatively small size (>1 cm) and a relatively small size (>1 cm). 2) may not require ESD protection, while segments 1'-4' still require protection. In addition, the presence of a passive capacitor structure with a monolithic common conductor layer as the lower electrode can reduce the response time (frequency) of the OLED. This reduction can be minimized by patterning the conductive layer into smaller parts.

[0070] Figure 2A and Figure 2B This protection arrangement is shown in Figure 2A and Figure 2B 100 , but with passive capacitor structures not present under all electrode segments. In particular, the conductive layer 20 is not continuous under all OLED segments, but is patterned under OLED segments 1′-4′ but not under 5′. Instead, another insulating layer 31 is added under electrode segment 5. Insulating layer 31 is also transparent and can be the same as or different from insulating layer 30. In this way, the total capacitance of the smaller OLED segments 1′-4′ is increased in a manner similar to that described for 100, while the capacitance of the larger OLED segment 5′ is relatively unaffected. In this embodiment, the vertical overlap between the bottom electrode segments 1-4 and the conductive layer 20 in the OLED segments 1′-4′ is 100%.

[0071] In 100 and 200, there is also a third capacitor structure formed between the power leads, which are laterally separated from the bottom electrode segment to which the power feeder is not connected. For example, the power lead 25 is laterally separated from the bottom electrode segment 1 by PDL 40. This forms a passive capacitor structure because the power feeder 25 is not connected to the electrode segment 1 (the power feeder 25 is connected to the electrode segment 2). Although the power feeders transmit current during the operation of the OLED device, they will not be powered when the device is not in operation (ESD protection is required at this time), and therefore can contribute to passively dissipating ESD. However, since both the power feeder and the bottom electrode are very thin, the overlapping area between the power feeder side and the bottom electrode segment side is relatively small, the capacitance will be very small, and therefore, in this case, its contribution to the total capacitance can be ignored.

[0072] In both 100 and 200, the relative overlap area between the bottom electrode segments and the underlying conductive layer 20 forming the passive capacitor structure (when present) is 100%. That is, the area of ​​the conductive layer 20 providing the passive capacitor structure is equal to or greater than the area of ​​the corresponding electrode segment. Because the total capacitance only needs to be increased to a level sufficient to provide ESD protection, the relative area of ​​the conductive layer 20 forming the passive capacitor structure can be less than 100% of the corresponding bottom electrode segment. Even though the capacitance will be less than the capacitance when the relative overlap area is 100%, when it is added to the inherent capacitance of the OLED, the overall capacitance can be sufficient to prevent ESD damage.

[0073] This is Figure 3A and Figure 3B The figure shows that Figure 3A and Figure 3B 3 are a top view and a cross-sectional view, respectively, of a segmented OLED device 300 similar to 200, but wherein the overlap area between the electrode segments and the conductive layer forming the second passive capacitor is less than 100%. In particular, the conductive layer 20 has been patterned so that its overlap area (90) with each bottom electrode segment 1-4 is 50%; that is, the conductive layer 20 forming the lower electrode of the passive capacitor structure overlaps only about 50% of each overlying electrode segment 1-4 forming the upper electrode of the passive capacitor structure.

[0074] The amount of overlap between the conductive layer and the bottom electrode segment is related to the capacitance provided by the passive capacitor. Ideally, the overlap area between the conductive layer and the electrode segment forming the passive capacitor structure should be at least 30% or more in order to provide significant capacitance. That is, the area of ​​the conductive layer that overlaps the electrode segment (which is the upper electrode of the second capacitor structure) or the total area of ​​all conductive layer portions that exist (which form the lower electrode of the second capacitor structure) is at least 30% of the area of ​​the electrode segment. More desirably, the overlap area is at least 50% or more, and most desirably, at least 70% or more.

[0075] In some examples of segmented OLED devices, it may be undesirable to place the power feed lines between the electrode segments and laterally separated from them. Such an arrangement may be susceptible to short circuits due to manufacturing defects. In addition, depending on the layout, overall size, and number of OLED segments, it may not be possible to install all necessary power leads (at least one per OLED segment) within the available distance (non-emitting gap) between the OLED segments. Some power feed lines may have an increased width (to minimize IR drop over their length) that cannot be accommodated within the available gap distance. In these cases, the power feed lines can be located below the plane of the electrode segments and above the transparent substrate.

[0076] Figure 4AA top view of a segmented OLED device 400 is shown, wherein the power feeder is located between the plane of the electrode segments and the transparent substrate, and is not in the same plane as the electrode segments. In particular, power feeders 15, 25, 35, 45, 55 are located above the transparent substrate 10, in the same lateral plane as the conductive layer. In this example, the conductive layer has been patterned into two separate conductive layers 22 and 24. Power feeder 15 is separated from conductive layer 22 by an insulating layer 31 in the form of a slot in 22 in electrical contact. Power feeders 25 and 45 are located in the space between 22 and 24 and are separated from conductive layer 24 in electrical contact by insulating layer 31 in the form of a slot. Power feeders 35 and 55 are separated from conductive layer 24 in electrical contact by insulating layer 31 in the form of a slot in 24 (which may be the same as or different from insulating layer 30). In any case, the power feeder is not in electrical contact with any part of the conductive layer. The power feeder makes contact with the appropriate electrode segment through a through hole passing through insulating layer 30 or 31 or both.

[0077] Figure 4B A cross section along line ZZ' is shown at 400. In 400, power feeders 25 and 45 are located directly below the non-emitting space between the electrode segments and are therefore not in the emission path. Power feeders 15, 35, 55 are connected to electrode segments 1, 3, and 5 through through holes 32 in insulating layer 30 (through holes for power feeders 25, 45 are not shown).

[0078] However, this may not always be possible, as the non-emitting space 80 may not have sufficient space for the required number of power feeders. In this case, it is necessary to place at least some of the power feeders below the electrode segments, in the same plane as the conductive layer. The insulating layer 30, located between the conductive layer and the upper surface of any power feeders and the bottom surface of the electrode segments, prevents any electrical contact between the power feeders and any electrode segments that they do not control.

[0079] Since it is not always possible to route all power feed lines under the non-emissive gaps between electrode segments, it may be necessary to route at least some power feed lines under (and electrically isolated from) one or more bottom electrodes of the OLED segments even though they are in the emissive path. Figure 5A This situation is shown in Figure 5A is a top view of a segmented OLED device 500, which is a heterogeneous array of seven individual OLED segments.

[0080] In 500, there are two columns of three OLED segments each; one column is 1'-3' (defined by corresponding bottom electrode segments 1-3), and the other column is 5'-7' (defined by corresponding bottom electrode segments 5-7). The two columns are separated by a single larger segment 4' (defined by corresponding bottom electrode segment 4). On the transparent substrate 10 are power feed lines (15, 25, 35, 45, 55, 65, 75) for each corresponding electrode segment (1-7), all of which are located between the three portions (22, 24, 26) of the conductive layer. The power feed lines are electrically insulated from each other and from the conductive layer portions 22, 24, 26 by an insulating layer 31. Figure 5A Not shown (but in Figure 5B ) is an insulating layer 30 on the power feed lines / conductive layer portions 22, 24, 26 / insulating layer 31, followed by electrode segments 1-7 laterally separated by PDL 40, and an organic layer 50 for light emission, a common top electrode 60 and an encapsulation 70.

[0081] In 500, different passive capacitor structures are formed by the overlap between electrode segments 1 and 5 and conductive layer portion 22, the overlap between electrode segments 2 and 6 and conductive layer portion 24, and the overlap between electrode segments 3 and 7 and conductive layer portion 26. These passive capacitor structures are connected in parallel between the bottom electrode segments and the conductive layer portions. These passive capacitor structures increase the total capacitance of OLED segments 1′-3′ and 5′-7′ and thus provide ESD protection. However, OLED segment 4′ has three different second capacitor structures, where the common electrode segment 4 overlaps with individual conductive layer portions 22, 24, 26. In this case, the total capacitance of OLED segment 4′ is the inherent capacitance of the OLED + the sum of the three capacitances of the passive capacitor structures formed between 4 and 22, 4 and 24, and 4 and 26.

[0082] In 500, all external contact pads for the power feed lines are located on the same side of the substrate. This arrangement is highly desirable for ease of device manufacturing and assembly. However, in order to contact the bottom electrode segments 5-7 at the far end of the device, some of the power feed lines must be located directly below the bottom electrode segment 4. This can be seen in the cross section of 500 along line ZZ' and in FIG. Figure 5B In this embodiment, power feed lines 55, 65 and 75 are all located below bottom electrode segment 4 and are electrically isolated from 4 by insulating layers 30 and 31. These power feed lines are all located in the emission path of OLED segment 4' and may be visible in some cases.

[0083] In the OLED segments 4' of 500, additional passive capacitor structures are formed between the power feeds 55, 65 and 75 (which are conductive) and the overlying electrode segments 4 when the device is not operating or no power is applied to those particular power feeds. This is because there is no electrical connection between these power feeds (which serve other electrode segments) and the overlying electrode segments 4 which are independent of the power feeds. During operation of the segmented OLED device, some of these power feeds may be powered and therefore will not act as passive capacitor structures at that time. However, since ESD protection is necessary when the device is not operating, such an arrangement still increases the overall capacitance of the OLED segments.

[0084] In the specific example of 500, only three power feed lines (whose width is relatively thin because there is only an array of seven OLED segments and therefore IR drop is not an issue) are located below the electrode segment 4, and therefore, the additional passive capacitance provided by the capacitor structures formed between the power feed lines 55, 65 and 75 and the bottom electrode segment 4 will be small because each corresponding passive capacitor structure is small. In this example, the overlap area between the power feed lines 55, 65, 75 and the electrode segment 4 is much less than 25% of the area of ​​the electrode segment. Therefore, in this example, the additional capacitance due to these passive capacitor structures is negligible.

[0085] However, a segmented OLED device may have a large number of individual segments; for example, 100-1000 segments. Since each segment has its own individual and unique power feed, there may be a large number of power feeds with their external contact pads all located on one side of the substrate. In addition, due to the size of such large devices, the power feeds may need to extend for long distances, and therefore, it may be necessary to increase their width (and overall conductivity) in order to prevent IR drops. In such an instance, an OLED segment located on or near one side of the array where the contact pads are located may have a large number of power feeds for other segments located below the electrode segments. If the sum of the overlapping areas of the electrode segments and all of their underlying power feeds is at least 30%, more desirably at least 50%, and most desirably at least 70% or more relative to the area of ​​the individual electrode segments, this may be sufficient to provide adequate ESD protection when the device is not operating.

[0086] Fig. 6AA top view of a portion of the structure of a large segmented OLED device 600 is shown, in which power feeds 601-615 are all routed under a single independent electrode segment 1 without electrical contact. This creates multiple overlap regions 90 between each power feed 601-615 and the overlying electrode segment 1 located above all of these power feeds. Since the power feeds 601-615 are not electrically connected to the electrode segments 1, this forms multiple passive capacitor structures in the overlap regions 90. The power feeds 601-615 extend outside the package 70 to form external contact pads along the same edge of the device 600. In this example, the power feeds are not all the same width; 601, 604, 607, 610 and 613 are all wider than the others. These wider power feeds are used to connect to electrode segments that are relatively far from the ends, and the increased width helps to minimize IR drop.

[0087] In this case, when the device is not operating, the overlap between each power feed line (acting as the lower electrode of the passive capacitor structure) and the overlying electrode segment (acting as the common upper electrode of the passive capacitor structure) forms a plurality of passive capacitor structures, wherein each power feed line is connected to another OLED segment. Since all OLED segments in the array are connected in parallel, the passive capacitance of one OLED segment will be the sum of the capacitance according to the total overlap of all underlying power feed lines with the overlying (common) electrode segment plus the capacitance of other independent OLED segments, for which the power feed line(s) also form passive capacitor structures in a manner similar to that described for 100.

[0088] Since in this example the sum of the areas of all passive capacitor structures formed by the overlapping regions between power feeds 601-615 and electrode segment 1 is greater than 50% of the electrode segment area, the total capacitance of that OLED segment (intrinsic OLED capacitance + sum of all passive capacitances created by passive capacitor structures formed by the power feeds and electrode segments, plus the capacitances of other independent OLED segments below with the same power feeds) will provide increased protection from ESD damage whenever the device is not operating or when those particular power feeds are not powered.

[0089] Figure 6B A portion of an OLED device structure 600 is shown along Fig. 6ACross section of line ZZ′. In this example, a separate conductive layer (i.e., 20 in other figures) is not required because the sum of the capacitance formed by multiple passive capacitor structures (indicated by arrows) formed by the power feeders and the overlying independent electrode segments and the inherent OLED capacitance is sufficient to provide ESD protection for that particular OLED segment. In fact, when the device is not operating, there are enough power feeders that together act as the lower electrode of the passive capacitor structure, sufficient to protect the overlying independent OLED segment, so that no separate conductive layer portion is required. The power feeders 601-615 can be located directly on the transparent substrate 10. The insulating layer 30, which acts as a shared dielectric layer of the passive capacitor structure, is located between and above the power feeders, so there is no electrical contact between the power feeders or between the power feeders and the electrode segment 1. The organic layer 50, the top electrode 60 and the encapsulation 70 complete the OLED segment 1′ defined by the electrode segment 1.

[0090] Because the capacitance increases as more parallel passive capacitor structures sharing a common bottom electrode (in this embodiment, formed between the power feed line and the bottom electrode segments of the individual OLED segments) are added, it is desirable that the power feed line, which acts as the bottom electrode of the passive capacitor structure, is also routed under the bottom electrode of more than one individual OLED segment; more desirably, under at least 5 individual segments, and most desirably, under 10 or more individual OLED segments. Using the power feed line as a passive capacitor structure for some OLED segments in the array can also be used in combination with the use of a common conductive layer for other OLED segments.

[0091] The transparent substrate 10 can be glass (including flexible glass) or a polymer material. Generally speaking, it will be flat and have a uniform thickness. The top surface of the substrate is the surface facing the OLED. Because the substrate will be part of the overall package of the OLED, it should be sufficiently impermeable to air and water so that the OLED will have the desired life. The substrate can be rigid or flexible. The substrate can have various types of glue layers (i.e., planarization layers, light management layers, etc.), which can be patterned or unpatterned and can be located on the top surface or the bottom surface. Rigid or flexible glass is preferred.

[0092] The conductive layer 20 acts as the lower electrode of the passive capacitor structure, which is separated from the bottom electrode segment of the OLED segment (which acts as the upper passive capacitor electrode) by an insulating layer. There is no direct electrical contact between the upper capacitor electrode and the lower capacitor electrode. For those specific OLED segments that increase the overall capacitance, the passive capacitor structure is not electrically connected to any part of the control circuit. Its mere presence can provide a reservoir or storage reservoir to accommodate any ESD voltage. In particular, it is not involved in the operation of the associated OLED segment in any way, including acting as a storage capacitor used to store power for light emission for the OLED segment. It is desirable that it is electrically isolated (not directly electrically connected to any other circuit at all) and is only used to help dissipate any ESD charge through the participation of the capacitance of the entire array. In some instances, the conductive layer can be connected to ground (which will allow faster dissipation), a voltage source that is separate and independent from the power supply of the OLED segment, or even connected to the common top electrode of the OLED array.

[0093] The conductive layer 20 should be as transparent as possible, since it will be in the emission path of the OLED segments. The conductive layer can be made of a thin metal layer such as silver or copper, a conductive metal oxide such as ITO, AZO, IZO, GZO, ZnO, TiN or SnO2, an organic material such as PEDOT:PSS, CNT (carbon nanotubes), graphene or conductive particles such as silver, nickel or copper suspended in a polymer binder (conductive ink), or any combination of these materials. It may contain auxiliary structures such as metal grid lines to improve the conductivity. It may consist of multiple layers. Preferably, the conductive layer is a conductive metal oxide, in particular ITO or AZO.

[0094] Ideally, the thickness of the conductive layer is between 5 and 500 nm; desirably between 10 and 250 nm; and most desirably between 20 and 150 nm.

[0095] Conductive layer 20 may be unpatterned, where it is deposited as a single continuous and uniform layer across the entire surface of the substrate. However, in other embodiments, it may be patterned. For example, it may be patterned so that it is located as a continuous and uniform layer only under the emitting area of ​​the array. Alternatively, it may be patterned as a single continuous layer that is not uniform, but contains features such as slots, cutouts along edges, or internal openings.

[0096] The conductive layer 20 can also be patterned in segments so that there is a portion that is a continuous layer only under some electrode segments but not all electrode segments. In such an example, the conductive layer is patterned into two or more electrically isolated portions. For example, it can be patterned so that a separate portion is only directly below each electrode segment. Alternatively, a single conductive layer portion can be located below two or more electrode segments, or a single electrode segment can be located above two or more different conductive layer segments. Different portions of the conductive layer can be separated laterally by non-conductive or insulating materials. There may be OLED segments in the array that do not have any conductive layer below the bottom electrode segments on the OLED structure. In such an example, there is no overlap.

[0097] Because in some instances not all OLED segments require additional ESD protection, it may also be desirable that the conductive layer overlaps less than all OLED electrode segments. In particular, at least one OLED segment in the array may not have an associated passive capacitor structure. In an associated passive capacitor structure, the bottom electrode of the OLED structure also serves as the top electrode of the passive capacitor structure in the same OLED segment. Because the additional capacitance required for ESD protection of any individual OLED segment depends on having additional parallel OLED segments with passive conductive structures, it may be desirable that the conductive layer overlaps at least two OLED electrode segments. In particular, in some embodiments, it will be desirable that the conductive layer overlaps the electrode segments of at least two OLED segments, but less than all OLED segments, so that at least one OLED segment does not have a passive capacitor structure. In some embodiments, it will be desirable that at least 20% of all OLED segments have an associated passive capacitor structure, and more desirably at least 50%.

[0098] Conductive layer 20 may be patterned using photolithography techniques, deposited using a mask, or uniformly deposited and then undesired portions removed (ie, by laser ablation).

[0099] In embodiments where the power feeds for individual OLED segments are located below electrode segments to which they are not electrically connected (i.e., independent OLED segments), the power feeds can form passive capacitor structures with the overlying and unconnected (independent) electrode segments whenever the OLED device is not operating (i.e., not connected to a power source), or whenever no current or voltage is applied through the power feeds (i.e., the OLED segments are in an "OFF" state). In this way, the power feeds can be used for the same purpose as the conductive layer 20 in terms of ESD protection for these embodiments, and perform in the same manner. However, the sum of the capacitances from the multiple passive capacitor structures formed between all power feeds and electrode segments must provide sufficient passive capacitance, and when added to the inherent OLED capacitance, the total capacitance provides sufficient ESD protection. It should be noted that if the power feeds are electrically connected to the overlying segment electrodes, the resulting structure is not a capacitor.

[0100] Each electrode segment should have only one power feeder, and each power feeder is electrically isolated from other power feeders and any independent electrode segments by a non-conductive or insulating material. "Independent" means any electrode segment (or corresponding OLED segment) that is not connected to and electrically isolated from that particular power feeder. Therefore, each OLED segment in the array has a single dedicated power feeder electrically connected to it, and all other OLED segments are independent of that power feeder. In some instances, the power feeder can be divided into two or more sub-feeders that are connected to the same electrode segment in different locations. In some cases, two or more separate but co-operating power feeders (considered equivalent to a single power feeder) can be connected to a single segment. For example, a driver with a maximum output of 10mA is connected to a 20cm 2 If the segment requires 1mA / cm 2 To produce the desired light output, the segment would require two power feeds (one per driver or one for each of the two channels of a multi-channel driver). 2 A segment can be driven by a single driver, but if necessary, the corresponding power feeder can be split into two paths to accommodate other power feeders in the device. Such an arrangement can help to distribute power more evenly across the segment, or reduce IR drop. However, in some instances, the same power feeder can be used for two or more segments. Segments sharing a common power feeder cannot be activated independently, and will transmit together and be treated as equivalent to a single segment.

[0101] There are external contact areas (also known as contact pads) on the outside of the package that are electrically connected to each power feeder within the package. Although the figures show the extension of the power feeder outside the package forming the contact area, the package on the power feeder can also be selectively removed to make electrical contact through the package. A controlled power source is then electrically connected (i.e., by welding or ACF) to these contact areas to power the power feeders and segmented electrodes within the package when necessary. Delivering an appropriate amount of power to the contact area within a suitable time period will cause the OLED segment to emit light at a desired brightness within that time period. The power delivered to the external contact pads is determined by a controller or driver. It is highly desirable that all contact pads for each power feeder are located on one side or edge of the substrate.

[0102] The location and distribution of the individual power feeds across the substrate surface will depend on the design of the array of OLED segments. Some power feeds may be located in non-emissive regions (i.e., in the gaps between segments and / or at the outer edges of the device), while other power feeds are located below the electrode segments and in the light path. Depending on the design, some segments may not have any power feeds located between or under them, while other segments may have multiple power feeds between or under them.

[0103] It is important that the IR drop along the power feeder is similar for all OLED segments, regardless of the distance to the external power source or the size of the OLED segments (larger segments require more power to operate than smaller segments). However, the IR drop can be minimized by adjusting the width (parallel to the substrate) or the height (above the substrate) of the power feeder. Therefore, in such a case, not all power feeders have the same width and height dimensions, which can also vary as a function of their length. In addition, not all power feeders have the same construction. For example, shorter power feeders can be made of conductive metal oxides, but longer power feeders can have auxiliary electrodes or be made of metals such as thin layers of silver.

[0104] If the power feeders are not located within the transmission path, they can be opaque or transparent as desired. If they are located in the transmission path, the power feeders should be as transparent as possible. The power feeders can be composed of any conductive material that can be patterned. For example, the power feeders can be made of metals such as silver or copper, 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 polymer binder (conductive ink), or any combination of these materials. The inherently opaque conductive material (i.e., silver) can be in the form of nanowires or grids, so that there are openings in the power feeder structure that allow some light to pass through, or can be thin enough that it is no longer opaque. Ideally, the resistivity of the power feeder should be less than 25 ohms / square, and desirably less than 15 ohms / square.

[0105] Desirably, the power feeder is composed of a conductive metal oxide, with ITO being particularly preferred. However, ITO is known to have a limited degree of lateral conductivity. If necessary, the power feeder formed of a conductive metal oxide may have an auxiliary electrode (e.g., an outer coating or sublayer of a conductive metal such as metallic silver or aluminum, or a conductive metal grid) to help minimize the IR drop over part or all of its length.

[0106] In general, the conductive material constituting the conductive layer or power feed line may have a relatively high refractive index, while the surrounding material may have a different, often much lower, refractive index. Such refractive index differences at the interfaces between the conductive material and adjacent materials may cause visible emission differences or emission reductions due to internal light refraction. Any visible emission differences due to the presence of mismatched materials in the optical path may be eliminated or at least reduced by matching the refractive index between the conductive layer or power feed line to other materials in direct contact (or at least minimizing any mismatch), or by incorporating an anti-refractive material in the segmented OLED device, where the refractive index of the anti-refractive material is more similar in magnitude to the refractive index of the conductive layer or power feed line. Ideally, the reflectivity difference (D ) between the transparent substrate area where the conductive layer or power feed line is located and the transparent substrate area where the gap between the power feed lines is located is 0.1%. R ) is 5% or less. To achieve this, it is desirable that the refractive index R of the conductive layer or power feeder is I The refractive index R of any material in direct contact with the conductive material I Ratio (higher R I / Lower R I ) is in the range of 1.00 to 1.06. The inclusion of an anti-refractive material helps make the emission from each segment in the device appear more uniform. It is important that the anti-refractive material and layer are non-conductive. Note that only R IThe difference in is important; it does not matter which material is higher and which is lower.

[0107] In order to form a passive capacitor structure having a conductive layer 20 or a power feeder as a lower electrode, and to prevent short circuits with the overlying electrode segments, the upper surfaces of these conductive structures are covered with non-conductive dielectric materials that separate them from the electrode segments. The dielectric material used for the passive capacitor structure can be an insulating layer 30, which can be patterned or unpatterned if necessary. The insulating layer 30 can also exist outside the overlapping area between the conductive structure used as the lower passive capacitor structure electrode and the electrode segment used as the upper electrode of the passive capacitor structure. In some embodiments, there may be portions of an auxiliary insulating layer 31. For example, the insulating layer 31 can be used to fill the conductive layer 20, the power feeder and the conductive layer, the power feeder or the space between different portions for planarization and electrically separate them. The insulating layer 31 may or may not be composed of the same (one or more) materials as the insulating layer 30.

[0108] The capacitance of the passive capacitor structure formed by the conductive layer 20 or power feed line, the insulating layer 30 (and 31, if present), and the electrode segments will depend on the composition and thickness of the dielectric insulating layer 30 (and 31, if present) and the amount of overlap between the capacitor electrodes. Therefore, the thickness and composition of the insulating layer 30 (and 31, if present) should be selected based on the overlap so that the passive capacitance, when added to the inherent capacitance of the particular OLED segment, will be sufficient to provide ESD protection.

[0109] The insulating layer 30 or 31 should be transparent and non-scattering light. The insulating material should have a resistance of not less than 1 megohm (MΩ), and more preferably not less than 2 megohms. Because the insulating layer is in the emission path, it is desirable that the ratio of the refractive index of the insulating material to the conductive material of the passive capacitor structure electrode should be in the range of 1.00 to 1.06. The insulating layer can be polymeric, but is preferably inorganic. Suitable inorganic insulating layers or materials include SiO2, SiN, SiON, Al2O3, TiO2, etc. and mixtures thereof. The vertical distance should be greater than 0.05 microns to prevent short circuits, and not greater than 10 microns, and ideally in the range of 0.1-1.0 microns to keep the device thin and light.

[0110] When the power feeder is located in the lateral space between the electrode segments, the electrical contact between the power feeder and its electrode segments is typically made on the side of the electrode segments. If the power feeder is located below the electrode segments, the electrical connection between the power feeder and the overlying segmented electrode is achieved through a through hole, which is a hole or path in the insulating material (i.e., insulating layer 30 or 31) that separates the two. The through hole runs from the top of the power feeder to the bottom or side of the segmented electrode. Ideally, the through hole is connected to the segmented electrode at a position corresponding to the non-emitting area of ​​the segmented OLED. The through hole can be formed by patterning the overlying insulating material so that at least a portion of the top surface of the power feeder is exposed or uncovered. Alternatively, the overlying insulating material can be uniformly deposited on the power feeder and the through hole, which is created by removing the material on the desired portion of the power feeder and thereby exposing the top surface.

[0111] The via is filled with a conductive material. When the segmented electrode is deposited on the material, some of the material of the segmented electrode may fill the via to make the connection. Alternatively, the via may be filled first with a conductive material and then the segmented electrode may be deposited on top of the filled via / insulating material. In some cases, it may be necessary to treat the power feed (before depositing the insulating layer) or the filled via (before depositing the segmented electrode) with a material that promotes conductivity through the connection.

[0112] The length and area of ​​the through hole are not critical, but should be sufficient to supply the necessary power to the segmented electrodes. The through hole can have any shape along the upper surface of the power feeder. In particular, it can extend along the length of the power lead. There can be more than one through hole between the power feeder and the electrode segment.

[0113] There is an array of individual electrode segments on a common substrate, as well as any other intervening layers. "Common" means that all OLED segments in the array share the same substrate, and are manufactured together as an array on that substrate. There are non-emissive lateral gaps separating the individual segments on all sides (except those located along the outer edges or corners of the device).

[0114] The segmented OLED device is a bottom emitter, and the bottom electrode segment is transparent. The transparent electrode segment should transmit as much light as possible, preferably with a transmittance of at least 70% or more desirably at least 80%. However, in some applications (i.e., microcavity devices), the transparent bottom electrode may be only translucent and partially reflective. Although the bottom transparent electrode can be made of any conductive material, metal oxides such as ITO or AZO or thin layers of metals such as Ag are preferred. In some cases, there may be auxiliary electrodes to help distribute the charge more evenly across the area of ​​the transparent electrode. Ideally, the resistivity of the electrode segment should be less than 25 ohms / square, and desirably in the range of 10-23 ohms / square.

[0115] In some embodiments, there is a pixel definition layer (PDL) that separates portions of one OLED segment from portions of another OLED segment, or along the periphery of the array. The PDL separates the electrode segments to prevent electrical contact, defines the outer edge of the array, and can be used to confine the organic layers to a single OLED segment. In some cases, it can be used to partially cover the electrode segments to prevent light emission in the PDL area (e.g., where the through holes are located in the area along the edge of the electrode segment). In other cases where there is no PDL layer in the gaps between the electrode segments, there may still be a PDL located along the periphery of the array. The PDL should be insulating (non-conductive).

[0116] In some embodiments, the PDL in the gaps between the bottom electrode segments will have approximately the same thickness as the electrode segments. This will create a relatively flat surface for depositing the overlying layer. In other embodiments, the PDL will be thicker than the electrode segments, and therefore a portion of the PDL will extend beyond the upper surface of the electrode segments in the gaps or along the outer edge of the array. In some instances, the extended portion of the PDL will also cover some portions of the upper surface on the electrode surface. In such a case, the PDL may cause undesirable light leakage or light guiding. In order to reduce light leakage, an absorbing dye can be added to the PDL. Alternatively, the PDL layer material can be opaque or black.

[0117] Suitable PDL materials can be polymeric or inorganic. Some examples of suitable polymeric PDLs include acrylic and polyimide polymers. Some examples of suitable inorganic PDLs include SiO2, SiN, and SiON. Ideally, the thickness of the PDL layer should not exceed 5 microns, and desirably be in the range of 0.2-3.0 microns.

[0118] Figure 7A typical composition of OLED layers of the type used for light emission in example OLED 1000 is shown. There will be one or more light emitting layers and a number of auxiliary layers to help facilitate and control charge movement between electrodes during light emission. In this particular example, the bottom electrode segment is an anode and the top electrode is a cathode.

[0119] Above the transparent electrode segment 514, there may be a hole injection layer (HIL, layer 501) as desired. The purpose of the HIL is to manage the transport of holes from the anode to the organic layer. Suitable hole injection materials are well known and commonly used. These layers can be a mixture of such materials and may contain dopants to modify their properties. Since it does not emit light, it does not contain an emissive material. Generally only one HIL is present. The selection of an appropriate material is not critical, and any material may be selected based on its performance. An example of a suitable HIL material is HAT-CN.

[0120] Located above the HIL (layer 501) is a hole transport layer (HTL, layer 502). The purpose of the HTL is to manage the transport of holes from the HIL to the light emitting layer above. Suitable hole transport materials are well known and commonly used. These layers can be a mixture of such materials and can contain dopants to modify their properties. Since it does not emit light, it does not contain an emitting material. There can be multiple HILs present. The selection of an appropriate material is not critical, and any material can be selected based on its properties. An example of a suitable HIL is NPB.

[0121] Located above the HTL (layer 502) is an exciton blocking layer (EBL; layer 503) as desired. Light emitting layers emit via the formation of excitons, which in some cases have sufficient lifetime to diffuse away from the site where they are formed. The purpose of the EBL is to confine the excitons within the LEL to maximize light emission. Suitable exciton blocking materials are well known and commonly used. These layers can be mixtures of such materials and may contain dopants to modify their properties. Since it is not light emitting, it does not contain emitting material. There may be multiple EBLs present. The selection of appropriate materials is not critical, and any material may be selected based on its performance. An example of a suitable EBL is mCP.

[0122] Located above the EBL (layer 503) is a first light emitting layer or unit (LEL1; layer 504). The light emitting layer (LEL) is a single layer and generally comprises one or more non-emissive host compounds and one or more light emitting dopants. Host materials and fluorescent, phosphorescent and TADF light emitting dopants suitable for light emitting layers or units are well known and commonly used. As previously defined, the light emitting unit can also be used for emission. The selection of appropriate materials is not critical, and any material can be selected based on its performance and emission characteristics.

[0123] Located above the LEL1 (layer 504) is a hole blocking layer (HBL; layer 505) as desired. Light emitting layers emit via the formation of excitons, which in some cases are not formed quickly enough before holes migrate toward the cathode. The purpose of the HBL is to confine the holes within the LEL to maximize light emission. Suitable hole blocking materials are well known and commonly used. These layers can be mixtures of such materials and can contain dopants to modify their properties. Since it is not light emitting, it does not contain emitting material. There can be multiple HBLs present. The selection of the appropriate material is not critical and any material can be selected based on its performance. An example of a suitable HBL is SF3-TRZ.

[0124] Located above the HBL (layer 505) is the charge generation layer (CGL, layer 506). The CGL (sometimes also called a connector or intermediate layer) is located between individual OLED light emitting units and is typically composed of multiple layers. This is because the CGL is structured so that electrons and holes are generated when a voltage is applied and injected into the adjacent organic emission layer. Therefore, the use of a CGL may convert one injected electron into multiple photons, allowing for higher brightness. In particular, it is desirable that the CGL is located between each light emitting unit in the stack. However, the light generating unit does not have to have adjacent CGLs on both sides. The top and bottom OLED light generating units of the stack generally have only one adjacent CGL. It is typically not necessary to use a CGL between the light emitting unit and one of the top or bottom electrodes, although a CGL can be used if desired.

[0125] Many different kinds of CGLs have been proposed and can be used for OLED stacking. For example, see US7728517 and US2007 / 0046189. In order to form a CGL, an np semiconductor heterojunction located at the interface of the n-type and p-type layers is typically required to generate charges. Therefore, the CGL will have two or more layers. For example, n-doped organic layer / transparent conductive layer, n-doped organic layer / insulating material, n-doped organic material layer / metal oxide layer and n-doped organic material layer / p-doped organic material layer have all been reported. A desirable metal oxide for CGL is MoO3. In some instances, the n-layer and the 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.

[0126] One desirable formulation for a CGL has three layers; an electron transport material doped with an n-dopant (e.g., 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, an intermediate layer with 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 Li or Ca layer, an intermediate layer of the same or different electron transport material and either an electron-deficient hole injection material or a hole transport material doped with a p-dopant.

[0127] Suitable electron transport and hole injection or transport materials and n-dopants and p-dopants for use in CGLs are well known and commonly used. These materials can be organic or inorganic. The selection of appropriate materials is not critical, and any material can be selected based on its performance. The thickness of the CGL should be desirably between 100 and 200 nm. range, although in some examples, thinner CGLs can be In many instances, the CGL will have an ETL or HBL on the anode side and an HTL or EBL on the cathode side to help improve charge transport and to help separate the charge generating dopants in the light emitting unit (if present) from the LEL. There can be multiple such layers, and they can be doped or undoped as desired.

[0128] Located above the CGL (layer 506) is a second light emitting layer or unit (LEL2; layer 507), which represents the second layer stack of the OLED device. Figure 7 , two LELs (layers 504 and 507) are separated by a CGL (layer 506), and therefore, Figure 7 The OLED stack in is a "dual stack" (or two layer stack) OLED. There can be one or more HTLs (doped or undoped) between the CGL (layer 506) and LEL2 (layer 507). LEL2 can emit the same color as LEL1 or a different color.

[0129] Located above LEL2 (layer 507 ) is at least one HBL (layer 508 ) which is similar to layer 505 described above.

[0130] Located above the HBL (layer 508) is an electron transport layer (ETL; layer 509). The purpose of the ETL is to manage the transport of electrons from the EIL to the light emitting layer below. Suitable electron transport materials are well known and commonly used. These layers can be a mixture of such materials and can contain dopants to modify their properties. Since it is not light emitting, it does not contain emissive material. There can be multiple ETLs. The selection of appropriate materials is not critical, and any material can be selected based on its performance. An example of a suitable ETL is TPBI.

[0131] Located above the ETL (layer 509) is an electron injection layer (EIL; layer 510) as required. The purpose of the EIL is to manage the transport of electrons from the cathode to the organic layers. Suitable electron injection materials are well known and commonly used. These layers can be a mixture of such materials and can contain dopants to modify their properties. Since it is not light emitting, it does not contain emissive materials. Generally only one EIL is present. The selection of appropriate materials is not critical, and any material can be selected based on its performance. An example of a suitable EIL material is LiF.

[0132] In the organic layer for light emission (50; Figure 7 There is a top electrode 60 above the layers 501-510 in FIG. Figure 7 In the middle is the cathode. It is preferably composed of a thicker metal or metal alloy layer, such as Al, Ag, Mg / Al, Mg / Ag, etc. The top electrode can be deposited by any known technique. The top electrode can be patterned in the non-emitting area, but is generally deposited uniformly on the emitting area. There needs to be a contact area (contact pad) outside the package, which is electrically connected to the top electrode inside the package for external power supply. Some examples of suitable materials for the top electrode are Al, Al / Mg, Ag / Mg and Ag.

[0133] There may be an optional protective layer or spacer layer above the top electrode ( Figure 7 Layer 511 in the package to prevent damage during packaging. These can be small molecule organic, polymeric or inorganic materials. Organic materials are preferred.

[0134] An encapsulation 70 is deposited or placed over the reflective cathode and any optional protective layers (if present). At a minimum, the encapsulation should completely cover the top and side light emitting areas and be in direct contact with the substrate. The encapsulation should be impermeable to air and water. It can be transparent or opaque. It should not be conductive. It can be formed in situ or added as a separate preformed sheet along with means for sealing the side edges.

[0135] An example of in-situ formation is thin film encapsulation. Thin film encapsulation involves depositing multiple layers with alternating layers of inorganic materials and polymers until the desired degree of protection is achieved. Recipes and methods for forming thin film encapsulation are well known, and any recipe and method may be used as desired.

[0136] Alternatively, encapsulation can be provided using a preform or cover glass that is attached at least above the sealing area and the enclosed area. The preform can be rigid or flexible. It can be made of glass (including flexible glass), metal or organic / inorganic barrier layer. It should have a thermal expansion coefficient close to that of the substrate to achieve a more robust connection. It may be necessary to attach the preformed encapsulation sheet above the sealing area using an airtight and waterproof adhesive such as silicon or epoxy resin adhesive, 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 glass can be specially designed to better fit the sealing area or promote better sealing. The cover glass and the sealing area can be designed together so that they can partially fit or lock into place before the seal is formed. In addition, the cover glass can be pre-treated to promote better adhesion to the sealing area.

[0137] For some applications, it is necessary to increase the degree of encapsulation. This can be achieved by providing an additional metal foil encapsulation (layer 513) attached to the encapsulation 70 by a pressure sensitive adhesive (layer 512). The use of metal foil not only provides a strong encapsulation, it also acts as a heat sink to prevent overheating that is harmful to the OLED device.

[0138] For many applications, a single stacked OLED device can provide sufficient emission for the intended purpose. For some applications, the required brightness exceeds that which can be provided by a single OLED stack. In such cases, two (e.g. Figure 7 In general, adding one OLED stack (i.e., two cells instead of one) will double the brightness produced, although the power required will also be doubled. A three-stack OLED will produce 3 times the brightness, but require 3 times the power, and so on. In the segmented OLED device of the present invention, as many stacks as necessary to produce the desired amount of brightness may be added; the only limit is the increase in voltage necessary to drive the device. Desirably, there are at least two stacks and as many as six stacks in a segmented OLED device.

[0139] Another way to increase the brightness of OLEDs is to incorporate the microcavity effect, especially when monochromatic emission is desired. To form a microcavity, one electrode is reflective and the other is semi-transparent so the 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 OLED segmentation of the device.

[0140] All OLED segments can emit white light or multi-mode light, and color filters are used to create the desired emission color for each specific segment. Although the various individual LELs or units within a segmented OLED device are not limited to providing the same color, some applications require monochromatic emission. For example, for many automotive taillight applications, all LELs or units should produce red light. It should be noted that although different LELs or units may all produce the same color of light, it is not necessary for all to have the same emission spectrum; the proportions of certain wavelengths in some units may be different from those in other units (i.e., one unit produces a spectrum with more short red wavelengths, while another produces more longer red wavelengths).

[0141] A method for making a bottom emitting segmented OLED device having an array of OLED segments, wherein at least one OLED segment includes a passive capacitor structure to increase the total capacitance, the method comprising the following steps in sequence:

[0142] 1) depositing a layer of transparent conductive material on a transparent substrate, wherein the conductive material will form a lower electrode of a passive capacitor structure;

[0143] 2) depositing a transparent electrically insulating material over the conductive layer, wherein the insulating material will form a dielectric in the passive capacitor structure;

[0144] 3) patterning transparent electrode segments and conductive power feed lines over the insulating material such that each electrode segment will have a power feed line and wherein at least one overlying electrode segment overlaps at least a portion of an underlying conductive layer; wherein the overlap between the conductive layer and the electrode segments (separated by the insulating material of step 2) forms a passive capacitor structure;

[0145] 4) depositing pixel definition material in the lateral spaces between the electrode segments, between the power feed lines, and between the electrode segments and the power feed lines of other electrode segments;

[0146] 5) depositing an organic layer for light emission over the upper surface of the electrode segment;

[0147] 6) depositing a common top electrode over the organic layer to complete the OLED segment including the bottom electrode segment, the organic layer and the top electrode; and

[0148] 7) Forming a package over the OLED segment array.

[0149] Another method for making a bottom emitting segmented OLED device having an array of OLED segments, wherein at least one OLED segment includes a passive capacitor structure to increase the total capacitance, the method comprising the following steps in sequence:

[0150] 1) patterning a conductive transparent material and a conductive power feeder on a transparent substrate such that the power feeder is not in contact with the conductive material, and filling the lateral space between the conductive material and the power feeder with an electrically insulating material, wherein at least some of the conductive material will form a lower electrode of the passive capacitor structure;

[0151] 2) depositing a transparent electrically insulating material over the conductive layer and the power feeder, wherein the insulating material will form the dielectric in the passive capacitor structure;

[0152] 3) forming a through hole in the insulating layer above the power feeder;

[0153] 4) patterning transparent electrode segments over the insulating material such that one electrode segment will be connected to a power feed line through the through hole of each OLED segment, such that at least one overlying electrode segment overlaps at least a portion of the underlying conductive layer, such that the overlap between the conductive layer and the electrode segment forms a passive capacitor structure together with the insulating material of step 2;

[0154] 5) depositing a pixel definition layer in the lateral spaces between the electrode segments;

[0155] 6) depositing an organic layer for light emission over at least the upper surface of the electrode segment;

[0156] 7) depositing a common top electrode over the organic layer to complete the OLED segment including the bottom electrode segment, the organic layer and the top electrode; and

[0157] 8) Forming a package over the OLED segment array.

[0158] Some useful variations on any of the above methods include:

[0159] - patterning the conductive layer so that it is common to all electrode segments;

[0160] - patterning the conductive layer so that it will overlap at least two electrode segments;

[0161] - Patterning the conductive layer so that it will overlap less than all electrode segments, so that some OLED segments do not have a passive capacitor structure.

[0162] Another method for making a bottom emitting segmented OLED device having an array of OLED segments, wherein at least one OLED segment includes a passive capacitor structure to increase the total capacitance, the method comprising the following steps in sequence:

[0163] 1) patterning conductive power feed lines on a transparent substrate and filling the lateral spaces between the power feed lines with an electrically insulating material, wherein at least some of the power feed lines serve as a conductive layer that will form a lower electrode of a passive capacitor structure;

[0164] 2) depositing a transparent electrically insulating material over the power feeder, wherein the insulating material will form the dielectric in the passive capacitor structure;

[0165] 3) forming a through hole in the insulating layer above the power feeder;

[0166] 4) patterning transparent electrode segments over the insulating material so that one electrode segment will be connected to one power feed line through the through hole of each OLED segment, so that the bottom electrode segment of one OLED segment overlaps at least a portion of a portion of the underlying conductive layer connected to another OLED segment, so that the overlap between the conductive layer connected to another OLED segment and the bottom electrode segment of one OLED segment forms a passive capacitor structure together with the insulating material of step 2;

[0167] 5) depositing a pixel definition layer in the lateral spaces between the electrode segments;

[0168] 6) depositing an organic layer for light emission over at least the upper surface of the electrode segment;

[0169] 7) depositing a common top electrode over the organic layer to complete the OLED segment including the bottom electrode segment, the organic layer and the top electrode; and

[0170] 8) Forming a package over the OLED segment array.

[0171] Some useful variations on the above approach include:

[0172] - Patterning the conductive layer so that it will overlap less than all electrode segments, so that some OLED segments do not have a passive capacitor structure.

[0173] - The area of ​​the OLED segment with the passive capacitor is less than 1 cm 2 .

[0174] - The area of ​​the OLED segment with the passive capacitor is at least 0.05 cm 2 .

[0175] - the overlapping area between the conductive layer portion(s) and the bottom electrode segment increases the total capacitance of the OLED segment by at least 0.2 nF.

[0176] - The overlapping area between the electrode segments and the conductive layer is at least 30% or more of the electrode segments.

[0177] Some desirable physical and performance characteristics of bottom-emitting segmented OLED devices include:

[0178] Brightness: 2,000-20,000cd / m 2 ;

[0179] Number of OLED segments: >200 (can be a mix of different sizes and shapes);

[0180] Active area: 25cm 2 or greater;

[0181] Segment size: <1cm 2 , and most preferably <0.5cm 2 ;

[0182] 2000cd / m 2 Current density: 13mA / cm 2 (2 stacks), 4.3 mA / cm 2 (6 layers);

[0183] 5000cd / m 2 Current density: 32mA / cm 2 (2 stacks), 9mA / cm 2 (6 layers);

[0184] 10000cd / m 2 Current density: 25mA / cm 2 (6 layers);

[0185] 20000cd / m 2 Current density: 50mA / cm 2 (6 layers);

[0186] Non-emitting gap: <1 mm, preferably <700 μm, and most preferably <200 μm; and

[0187] All electrical contact areas (bottom and top electrodes) on the outside of the package are located along only one edge of the device.

[0188] The above description describes several different embodiments. Individual features from any embodiment may be combined without restriction unless mutually exclusive.

[0189] In the above description, reference is made to the accompanying drawings forming part thereof, and specific embodiments that can be put into practice are shown therein by way of illustration. These embodiments are described in detail to enable those skilled in the art to practice the present invention, and it should be understood that other embodiments may be utilized, and that structural, logical and / or electrical changes may be made without departing from the scope of the present invention. Therefore, the description of any exemplary embodiment should not be construed as limiting. Although the present invention has been described for illustrative purposes, it should be understood that such details are only used for this purpose, and those skilled in the art may make changes without departing from the spirit and scope of the present invention.

[0190] Modeling and experimental results

[0191] The ESD reliability testing of segmented OLED devices for automotive applications is grouped into different categories or models, corresponding to the scenarios to which the device may be exposed. A more challenging scenario for OLED devices is the ESD Human Body Model (HBM), which represents the moment when the charge is transferred from the operator to the device (typically through a finger). The HBM ESD reliability testing is governed by the JEDEC-JS-001-2017 test standard.

[0192] exist Figure 8 When switch S1 is closed, a 0.1nF capacitor (C HBM ) test circuit is charged to a standard voltage level (V HBM ), and then when switch S2 is closed, the HBM ) to discharge the test OLED device. Table 1 lists the HBM V HBM Standard classification levels, where the level chosen determines the amount of charge to which the device is exposed during testing.

[0193] Table 1: ESD sensitivity classification for HBM testing

[0194] Classification <![CDATA[V HBM ]]> 0 0-250V 1A 250-500V 1C 1000-2000V 2 2000-4000V 3A 4000-8000V 3B >8000V

[0195] When the charge is transferred to the OLED, a voltage (V OLED ), where the greater the charge transfer, the higher the voltage. This can be measured by using HBM test parameters and OLED capacitance (C OLED ) performs a simple charge balance to estimate V OLED , as shown below, where Q is the charge in coulombs:

[0196] Q 最终 =Q 初始 (1a)

[0197] V OLEDx(C OLED +C HBM )=C HBM x V HBM (1b)

[0198] V OLED =(C HBM x V HBM ) / (C OLED +C HBM )(1c)

[0199] If V OLED Maintain a certain voltage limit (V LIM ) below which the OLED will not degrade or be damaged. This voltage limit is a characteristic of the organic stack and is typically determined experimentally. If V is expected to be reached under the test conditions, LIM , additional components, such as passive capacitor structures, can be incorporated into the design to mitigate the voltage to which the OLED is exposed.

[0200] As shown in Table 2a and Table 2b, at V HBM Under the test conditions of 2kV and 8kV, V is calculated according to Equation 1 for different OLED segment areas and the number of organic stacking layers for red cars. OLED Note that in this experiment, the capacitance per unit area of ​​the dual-stack red automotive OLED device is 21.7nF / cm 2 , while a similar six-layer device is 6.8nF / cm 2 All examples are simple bottom-emitting OLEDs and none include passive capacitor structures.

[0201] Table 2a: Calculated V for 2-stack OLED segments OLED

[0202]

[0203] Table 2b: Calculated V for 6-stack OLED segments OLED

[0204]

[0205] If the calculated V OLED Exceeding the V of the organic stack LIM , then device damage due to ESD is likely to occur and additional protection is required. In the devices of Table 2a-Table 2b, it has been experimentally determined that all 0.38 cm 2 The dual-stack red automotive OLED segments have passed the 2kV VH BM ESD test, but many 0.17cm 2 The segment did not pass, which indicates that the VLIM Between 24V and 53V. The data show that the V LIM About 40V and a conservative 120V respectively.

[0206] For additional capacitive protection, the required C 无源 It can be calculated as follows:

[0207] Q 最终 =Q 初始 (2a)

[0208] V LIM x(C OLED +C 无源 +C HBM )=C HBM x V HBM (2b)

[0209] C 无源 =(C HBM x V HBM ) / V LIM -C OLED -C HBM (2c)

[0210] Since each OLED segment’s V LIM depends on the formation of the OLED, so assuming a V LIM range and calculate the required C according to Equation 2c 无源 Tables 3a-3b and 4a-4b show the V HBM The different segment areas of double stack and six stack at 2kV and 8kV are LIM C required within the range 无源 . Note that C 无源 Negative values ​​of indicate that these particular OLED segments do not require ESD protection, and they are included here only to indicate how close particular scenarios are to device damage.

[0211] Table 3a: For V HBM = C required for 2kV 2-stack OLED segment 无源

[0212]

[0213] Table 3b: For V HBM = 8kV required C for 2-stack OLED segment 无源

[0214]

[0215] For VHBM The above-mentioned double-stacked OLED device (with V LIM is 40V), it is estimated that 0.38cm 2 and 0.25cm 2 The segment size of 0.17 cm does not require additional capacitance, although the latter of the two areas will approach the limit. 2 、0.10cm 2 and 0.05cm 2 The segments require 1.21nF, 2.73nF and 3.82nF C for each segment respectively. 无源 . Higher V LIM The value will naturally reduce the required C 无源 For V HBM For a dual-stack OLED at 8 kV, ESD protection is required under most conditions explored (Table 3b).

[0216] Table 4a: For V HBM = C required for 2kV 6-layer OLED segment 无源

[0217]

[0218]

[0219] Table 4b: For V HBM = 8kV required C for 6-layer OLED segment 无源

[0220]

[0221] For six-stack OLED and 2kV V HBM (Table 4a), V LIM 0.38cm above 120V 2 and 0.25cm 2 The OLED segment will not require C 无源 , although the latter is close to the limit. Under those conditions, it was calculated that six layers of 0.17 cm 2 、0.10cm 2 and 0.05cm 2 The OLED segments require C of 0.41nF, 0.89nF and 1.23nF per segment respectively. 无源 For 0.25cm 2 The segmentation, in V LIM At 80V, each segment will require a 0.71nF C 无源 . Higher V LIM The value will of course reduce the C required for the OLED segment无源 For V HBM Segmentation of a six-stack OLED at 8 kV for all segment sizes and explored V LIM The conditions all require ESD protection (Table 4b).

[0222] In this experiment, the 6-layer OLED formulation represents a relatively low intrinsic capacitance (C OLED =6.8nF / cm 2 )’s actual OLED formula. Its V LIM is estimated to be 120 V. Obviously, the smaller OLED segments with lower intrinsic capacitance will experience the highest voltage when exposed to ESD. For example, when V HBM =2kV, a 6-layer 0.05cm 2 The segment will experience 456V when V HBM = 8kV, 1822V will be experienced (see Table 2b). This is much higher than the V LIM To avoid ESD damage, the 0.05cm 2 The voltage experienced by the segment, assuming V LIM is 120V, when V HBM = 2kV, the minimum capacitance that the passive capacitor structure needs to supply is about 1.23nF (see Table 4a). Similarly, for the inherent capacitance of 21.7nF / cm 2 And V LIM Below 60V for 2-stack formulations, when V HBM =2kV, the minimum capacitance that the passive capacitor structure needs to supply will be 1.32nF (see Table 3a).

[0223] Based on the above, it is desirable that the addition of the passive capacitor structure(s) of the OLED segment increases the overall capacitance compared to the OLED segment without the passive capacitor structure so as to reduce V LIM Since the capacitance of the passive capacitor structure(s) depends directly on the overlap between the common conductive layer and the bottom electrode of the OLED segment, it is desirable that the overlap increases the total capacitance of the OLED segment by at least 0.2 nF, and more desirably by at least 0.4 nF, or most desirably by at least 1.0 nF.

[0224] Parts List

[0225] ZZ′ cutting plane / direction line; 1′-7′ OLED segment; 1-7 corresponds to the bottom segment electrode of the OLED segment; 15 power feed line of segment electrode 1; 25 power feed line of segment electrode 2; 35 power feed line of segment electrode 3; 45 power feed line of segment electrode 4; 55 power feed line of segment electrode 5; 65 power feed line of segment electrode 6; 75 power feed line of segment electrode 7; 10 common transparent substrate; 20 conductive layer; 22, 24, 26 conductive layer portion; 30, 31 insulating layer; 32 through hole; 40 pixel definition layer between each segment electrode; 50 organic layer for light emission; 60 top electrode; 70 encapsulation; 80 non-light emitting gap between each segment electrode; 90 overlap between conductive layer and bottom electrode segment; 95 control circuit; 100 – 400 A segmented OLED device having 5 OLED segments; 500 A segmented OLED device having 7 OLED segments; 600 Segmented OLED device having multiple conductive layer portions; 601-615 conductive layer portions; 1000 OLED device; 501HIL; ​​502HTL; 503EBL; 504LEL1; 505HBL; 506CGL; 507LEL2; 508HBL; 509ETL; 510EIL; 511 optional protective layer; 512 pressure sensitive adhesive; 513 metal foil encapsulation / heat sink; 514 bottom electrode segment; C HBM Test circuit capacitor; C OLED The capacitance of the associated OLED structure in the OLED segment; C O1 ′–C O5 Capacitance of the OLED structure in 'OLED segment 1'-5'; C 无源 The capacitance of the associated passive capacitor structure in the OLED segment; C P1 ′-C P5 ′Capacitance of passive capacitor structure; R HBM Test circuit resistor; S1 first switch; S2 second switch; V HBM Standard voltage level; V OLED OLED voltage.

Claims

1. A segmented bottom emitting OLED device comprising an array of a plurality of OLED segments arranged on a common transparent substrate, wherein the array forms an emitting region, wherein each OLED segment is separated by a non-emitting gap; wherein each OLED segment is defined by a transparent bottom electrode segment, an organic layer for light emission, and a top electrode; Wherein, between the bottom electrode segment in at least one OLED segment and the substrate, there is a transparent insulating layer closer to the bottom electrode segment and a transparent conductive layer closer to the substrate, so that the overlapping area between the bottom electrode and the conductive layer forms an associated passive capacitor structure, wherein 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 layer is the lower electrode of the passive capacitor structure.

2. The OLED device of claim 1, wherein the conductive layer is patterned.

3. The OLED device of claim 2, wherein the conductive layer is patterned into two or more portions that are electrically isolated from each other.

4. The OLED device of claim 2 - claim 3, wherein in at least one OLED segment, the overlapping area between the conductive layer portion(s) and the bottom electrode segment increases the total capacitance of the OLED segment by at least 0.2 nF.

5. The OLED device of claim 2-claim 3, wherein in at least one OLED segment, the overlap area between (one or more) conductive layer portions and the bottom electrode segment is 30% or more of the area of ​​the bottom electrode segment.

6. The OLED device according to claim 3, wherein: The bottom electrode segments of at least one different OLED segment in the array are free of any overlap with the conductive layer portion except for those OLED segments having associated passive capacitor structures such that no passive capacitor structure is associated with the at least one different OLED segment.

7. The OLED device of claim 6, wherein the size of the at least one different OLED segment without the passive capacitor structure is 1.0 cm 2 or larger.

8. An OLED device according to claim 1, wherein the bottom electrode of each OLED segment in the array is electrically connected to a dedicated power feed line that controls the light emission, wherein the power feed line is arranged laterally between the bottom electrode segments and is electrically isolated from other power feed lines and any independent electrode segments.

9. The OLED device of claim 3 , wherein the bottom electrode segment of each OLED segment in the array is electrically connected to a single power feed line that controls the light emission, wherein the power feed line is laterally arranged between the conductive layer portions and is electrically isolated from other power feed lines and the conductive layer portions, and is electrically isolated from the bottom electrode segment of any independent OLED segment by the insulating layer.

10. The OLED device of claim 9, further comprising at least one power feed line arranged to pass under at least one bottom electrode segment in the emission region of an individual OLED segment.

11. The OLED device of claim 10, wherein any dedicated power feed line arranged to pass under at least one bottom electrode segment in the emission region of an individual OLED segment is connected to its corresponding bottom electrode segment through a via in the insulating layer.

12. The OLED device of claim 11 , wherein there are a plurality of power feed lines beneath the bottom electrode segments of the individual OLED segments, such that overlap between all power feed lines and the bottom electrodes of the individual OLED segments forms an associated passive capacitor structure, wherein the bottom electrode segments are upper electrodes of the passive capacitor structure, the insulating layer is a dielectric of the passive capacitor structure, and the plurality of power feed lines together are lower electrodes of the passive capacitor structure.

13. The OLED device of claim 12, wherein for at least one independent OLED segment, the overlap area between the plurality of power feed lines and the bottom electrode segment in the associated passive capacitor increases the total capacitance of the independent OLED segment by at least 0.2 nF.

14. The OLED device of claim 13, wherein in the associated passive capacitor of the individual OLED segment, the total overlap between the summed area of ​​power feed lines and overlying bottom electrode segments is 30% or more of the area of ​​the bottom electrode segments.

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