Abstract:
An optoelectonice device array includes a plurality of packages, each enclosing an optoelectronic device, and positioned in at least one row. Each package overlaps at least one adjacent package, and may be hermetically sealed.

Description:
BACKGROUND 
     Optoelectronic devices generally include light-emitting devices and photovoltaic devices. These devices generally include an active layer sandwiched between two electrodes, sometimes referred to as the front and back electrodes, at least one of which is typically transparent. The active layer typically includes one or more semiconductor materials. In a light-emitting device, e.g., an organic light-emitting diode (OLED) device, a voltage applied between the two electrodes causes a current to flow through the active layer. The current causes the active layer to emit light. In a photovoltaic device, e.g., a solar cell, the active layer absorbs energy from light and converts it to electrical energy which generates a flow of current at some characteristic voltage between the two electrodes. 
     The light is transmitted through at least one of the electrodes of an OLED device. The design of a suitable transparent electrode requires that it provide in-plane electrical conductivity (favoring a thicker layer of material) and that it provide optical transmission through its thickness (favoring a thinner layer of material). To resolve these opposing constraints on the electrode design, it is preferred to limit the size of individual light emitting regions (pixels), and thus limit the amount of current that is flowing laterally in the plane of the electrode. If the current is low, the resistive losses in the electrode are low and the resulting device is efficient. In the one case, a pixel is defined by unlit lines that define its perimeter, and the current is bused to these regions. In another case, the pixel may be defined by points that define its perimeter, and current is bused to the electrode(s) at these points. In either case, the unlit regions interrupt the otherwise uniform appearance of an OLED. The typical maximum dimension for a pixel in the direction of current flow is on the order of 1 cm before excessive loss and non-uniform appearance results. Approaches to solving this problem include making the unlit regions very small (increasing the complexity of the manufacturing process) or to obscure them with a diffusing film (reducing efficiency and adding cost). Thus it is desirable to decrease the appearance of unlit regions so that large uninterrupted areas light can be created. More generally, it is desirable to configure large arrays of lighted areas from individual pixels while providing design flexibility. Accordingly, it is desirable to configure pixels in an arbitrary ordered on disordered array patterns, to introduce pixels of different size, shape, color and brightness, and spacing, and also to be able to replace individual pixels in the array. 
     BRIEF DESCRIPTION 
     Briefly, in one aspect, the present invention relates to an array including a plurality of packages positioned in at least one row, each package enclosing an optoelectronic device; each package overlaps at least one adjacent package. Each package may include an edge seal zone defining an electroactive area; at least a portion of the edge seal zone is transparent; the electroactive area of a first package in each row is overlapped by the transparent portion of the edge seal zone of an adjacent package; the transparent portion of the edge seal zone of each package other than the first package in each row overlaps the electroactive area of an adjacent package; and optionally, wherein the plurality of packaged optoelectronic devices is configured to form a continuous light emitting area. In some embodiments, a portion of the edge seal zone of each package is non-transparent, and the electroactive area of each package in the row overlaps the non-transparent portion of the edge seal zone of an adjacent package. The packages may be hermetically sealed. 
     In another aspect, the present invention relates to a package enclosing an optoelectronic device that includes an edge seal zone defining an electroactive area. At least a portion of the edge seal zone is transparent and a portion of the edge seal zone being non-transparent, and the non-transparent portion of the edge seal zone includes a conductive layer configured to connect an anode and a cathode of the optoelectronic device to an external power source via a plurality of terminals. Optionally, an electrically insulating layer is disposed between the anode and the conductive layer in the non-transparent portion of the edge seal zone, and configured to electrically isolate the anode from the cathode. In some embodiments, the cathode and the anode extend through a non-transparent portion of the edge seal zone. The packages may be hermetically sealed. 
     In yet another aspect, the present invention relates to an optoelectronic device having an unpatterned electrode comprising a transparent conductive oxide, particularly indium tin oxide. The device may additionally include a metallization layer directly disposed on the unpatterned electrode and configured to be in electrical communication with the unpatterned electrode and a power source. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a cross sectional view of a package for use in the arrays of the present invention. 
         FIGS. 2A-2D  are sectional views through layers of a package used in the lighting arrays of the present invention. 
         FIG. 3  is a schematic view of an array according to the present invention showing overlapping packaged optoelectronic devices. 
         FIG. 4  is a schematic diagram of an array according to the present invention having packaged optoelectronic devices oriented orthogonally to each other. 
         FIG. 5  is a schematic diagram of an array according to the present invention having a single row of packaged optoelectronic devices oriented with non-transparent portions of the edge seal zone linearly aligned. 
         FIG. 6  is a schematic view of an array according to the present invention having two rows of packaged optoelectronic devices oriented with non-transparent portions of the edge seal zone linearly aligned. 
         FIG. 7  is a schematic diagram of an array according to the present invention having a single row of packaged optoelectronic devices oriented with non-transparent portions of the edge seal zone linearly aligned. 
         FIG. 8  is a schematic view of an array according to the present invention having two rows of packaged optoelectronic devices oriented with non-transparent portions of the edge seal zone linearly aligned. 
         FIG. 9  is a schematic view of a package having two non-transparent portions of the edge seal zone. 
         FIG. 10  is a schematic diagram of an array according to the present invention having a single row of packaged optoelectronic devices oriented with non-transparent portions of the edge seal zone parallelly aligned. 
         FIG. 11  is a schematic view of an array according to the present invention having two rows of packaged optoelectronic devices oriented with non-transparent portions of the edge seal zone parallelly aligned. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a cross sectional view of optoelectronic device package  10  that is suitable for use in the lighting arrays of the present invention, showing first barrier layer  110 , first electrode  120 , electroactive layer(s)  130 , second electrode  140 , optional substrate  150 , and second barrier layer  160 . In embodiments where substrate  150  is not present, second electrode  140  may be disposed directly on second barrier layer  160 . Adhesive layer  170  is disposed between first barrier layer  110  and first electrode  120 , and between first barrier layer  110  and second barrier layer  160 , forming edge seal zone  180 . In some embodiments, second electrode  140  may be coextensive with substrate  150 , and adhesive layer  170  may be partially disposed on second electrode  140 , forming edge seal zone  180 . In other embodiments, substrate  150  may be coextensive with layers  160  and  180 . The edge seal zone The geometry of the edge seal zone is designed to minimize ingress of water and oxygen; adhesive layer  170  forming the bond between first and second barrier layers  110  and  160  is thin and broad and thus provide the preferred geometry. The adhesive material of adhesive layer  170  is selected to provide a strong bond between the substrate and the backsheet, and to be relatively impermeable to moisture and oxygen ingress. The adhesive is free from moisture and chemically inert so that it does not degrade the materials that make up the device, particularly the electrode and the materials of the electroactive layers. To the extent that adhesive  170  extends to the edge seal zone  180  beyond the light emitting region, it should be transparent. A wide range of adhesives including transparent thermoplastics, pressure sensitive adhesives, acrylics, and thermosetting epoxies and urethanes are potentially suitable. Low cost materials and processing are, for example, enabled by selecting a heat seal material such as Rohm &amp; Haas Adcote 37T77 which is provided as a dispersion that can be pre-applied to the barrier layers and then dried. Lamination of the barrier layers to the OLED device then can be completed with brief exposure to moderate heat and pressure, for example in a continuous roll lamination process. Optional adhesive layer  190  is disposed between second electrode  140  and second barrier layer  160  when substrate  150  is present. 
     Substrate  150  and first and second barrier layers  110  and  160  may be opaque or transparent, although at least one surface of the device, that is, first barrier layer  110  or substrate  150  and/or second barrier layer  160  is transparent in order that light emitted or absorbed by device  10  may pass through from or to electroactive layer(s)  130 . In one example, substrate  150  is transparent and composed of glass or a plastic such as polyesters (PET, PEN). The barrier layers are each relatively impermeable to moisture and oxygen; transparent materials suitable for use as a barrier layer include glass and ultra high barrier (UHB) films, for example, as described in U.S. Pat. No. 7,015,640, U.S. Pat. No. 7,154,220, and U.S. Pat. No. 7,397,183 assigned to the General Electric Company. Metal foils are suitable for opaque barrier layers. Second electrode  140  may be either a cathode or an anode; in some embodiments, second electrode  140  is the anode. In particular, second electrode  140  may be an anode composed of indium tin oxide (ITO). Electroactive layer(s)  130  is (are) one or more layers that collectively act to emit (for an OLED device) or absorb (for a PV device) light, and may include hole and electron injecting layers, hole and electron transporting layers and emissive layers. Various means of depositing the layers are known in the art, including vacuum and non-vacuum processes. Materials suitable for use in OLED devices and PV devices, and methods for manufacturing such devices are well known and will not be described here in detail. 
       FIG. 2A  is a transverse sectional view through an electroactive layer of package  20  that is suitable for use in the lighting arrays of the present invention, showing insulating layer  201 , electroactive area  210 , and exposed layers  250  that underlie area  210 , and include an electrode, a substrate, adhesive layer(s), and/or barrier layer(s). In a particular embodiment, the electrode is the anode; more particularly, the anode is composed of ITO. Electroactive area  210  includes a second electrode and electroactive layers sandwiched between the electrodes in addition to the underlying layers. Device  20  is depicted as a single pixel, that is, a single light emitting expanse, but may include multiple smaller pixels. Insulating layer  201  is typically thin, and has about the same thickness as electroactive area  210 , and has a smooth boundary with electroactive area  210 . The insulating layer is confined to edge seal zone  226 , and does not extend into electroactive area  210 . Insulating layer  201  may be composed of various organic or inorganic insulators. In one example, a low viscosity cyanoacrylate adhesive with a viscosity of about 1-10 cPs may be applied to form a thin insulating coating prior to depositing electrode  220 . In another example, a thin layer (less than 1 micron) of inorganic silicon dioxide may be deposited through a mask to form insulating layer  201 . Organic materials may be applied by any of various printing or coating techniques; inorganic materials may be deposited by vapor deposition methods, for example, vacuum evaporation, sputtering, and chemical vapor deposition. 
     In one embodiment, device  20  is manufactured without patterning the anode. Such a process may be more economical because fewer steps are required, and may also yield a device with improved properties. In a non-limiting example, an ITO layer is provided on a plastic substrate; a transparent UHB layer may be provided between the ITO layer and the substrate or on the other surface of the substrate. The substrate region defines the approximate final shape of the device. The substrate may be in a continuous roll format or a large panel, so that portions of multiple regions may be coated. An insulating layer composed of an organic material may be applied to the unpatterned anode from a low viscosity coating composition by any of various printing or coating techniques, or an inorganic insulating layer may be deposited on the unpatterned anode by vacuum evaporation or other vapor deposition methods. The step height difference at the edge of the coating is typically minimized. Electroactive layers are deposited directly on the unpatterned anode, leaving a gap between the electroactive area and the perimeter of the substrate on some or all edges. A metal cathode layer is deposited directly on the insulating layer and electroactive layers, and optionally on selected portions of the anode, through a mask. The metal layer may be formed, for example, via a vapor deposition process or a printing-type process using conductive ink. In an alternate embodiment, the ITO anode is selectively removed by an etching process from the region otherwise defined by insulating layer  201 , thus exposing the bare substrate  150  and obviating the need for insulating layer  201 . The subsequent steps of depositing electroactive layers and a cathode layer are unaltered.  FIG. 2B  is a transverse sectional view through an electrode layer of one embodiment of package  20 . The electrode layer  220  shown is the one that is not disposed on the substrate, analogous to first electrode  120  of  FIG. 1 . In this embodiment, the first electrode  220  is the cathode and may be opaque; an OLED device having this configuration is described as bottom emitting. In other embodiments, the layer is the transparent electrode, and is described as top-emitting.  FIG. 2B  shows cathode area  220 , underlying layers  250  that are the base for forming the transparent portions of the edge seal zone, and optional areas  203 . Cathode area  220  and conductive areas  203  include a transparent or opaque conductive layer. Suitable materials for the conductive layer of areas  220  and  203  are known in the art and include metals in elemental form, such as aluminum and silver, and transparent conductive oxides such as ITO and zinc tin oxide. In particular, a thin layer of aluminum may be used. In cathode area  220 , the layer is disposed over and is coextensive with insulating layer  201  and electroactive area  210  (not shown). Optional conductive areas  203  are disposed directly on the anode. Use of an additional conductive layer in electrical contact with the anode is particularly desirable to improve conductivity of an anode composed of a material with limited intrinsic conductivity such as ITO. Moreover, by adding a conductive layer, for example a metal, a low resistance electrical contact to the anode in area  203  may be more readily formed. 
     Non-transparent edge seal zone  226  includes conductive areas  203  that are in electrical communication with the anode, that are composed of two conductive layers without an insulating layer between, shown in  FIG. 2C , and an extension of cathode area  220  and the underlying anode and the insulating layer separating them, shown in  FIG. 2D , that is composed of two layers of conductive material and the insulating layer that prevents shorting between the conductive layers. In the embodiment where the ITO is etched away in the region otherwise defined by insulating layer  201 , the cathode area  220  is similarly in electrical communication with the region that extends to non-transparent edge seal zone  226 , and is composed of only one conducting layer. 
     Hermetic packaging of the device is completed using suitable structures and methods. Various types of hermetic packages and methods for manufacturing them have been described in U.S. patent application Ser. No. 12/336,683, filed on 17 Dec. 2008, Ser. No. 12/510,463, filed on 28 Jul. 2009, and Ser. No. 12/470,033, filed on 21 May 2009, and Ser. No. 12/570,024, filed on 30 Sep. 2009, the entire contents of which are incorporated within by reference. For example, a transparent protective backsheet may be bonded to the back of the device. The protective backsheet may be positioned and aligned with the substrate so that part of edge seal zone  226  in electrical communication with the anode and the cathode is exposed. Suitable materials for the transparent backsheet include glass or plastic with a barrier film. It may be bonded to the underlying layers with an optically transparent adhesive that is typically selected to provide a strong bond, and is free from moisture and chemically inert so that it does not degrade the OLED, and relatively impermeable to moisture and oxygen edge ingress. The seal geometry is designed to be sufficiently thin and wide to minimize ingress. 
       FIG. 3  is a schematic view of array  30  showing overlapping optoelectronic device packages  310  and  320 . The transparent portion of edge seal zone  312  of device  310  overlaps electroactive area  324  of device  320  and transparent portion  322  of device  320  overlaps electroactive area  314  on the reverse surface of device  310 . Light emitted by an OLED or to be absorbed by a PV device is able to pass through the overlapped transparent portions. For an OLED, electroactive areas  314  and  324  may be positioned without an intervening non-light emitting area, forming a continuous light emitting area. It should be noted that the present invention is not limited to packages having a transparent edge seal zone; in such embodiments, light emitting or light absorbing areas may be separated by non- emitting/absorbing areas. 
       FIG. 4  a schematic view of array  40  showing overlapping packages  410  and  420  oriented orthogonally to each other. The transparent portion  422  of edge seal zone  412  of device  410  overlaps electroactive area  424  of device  420 , and electroactive area  414  of device  410  overlaps non-transparent portion of edge seal zone  426  of device  420 , forming a continuous light emitting or absorbing area on one surface of the array. 
       FIG. 5  is a schematic view of array  50  showing overlapping packages  510 ,  520 ,  530 , and  540  arranged in one row and oriented with non-transparent portions  516 ,  526 ,  536 ,  546  of the edge seal zone of each device linearly aligned. Electroactive area  514  of the first device in the row, device  510 , is overlapped by transparent portion  522  of the edge seal zone of adjacent device  520 . Transparent portions  532  and  542  of the edge seal zones of devices  530  and  540  in the row overlap electroactive areas  524  and  534  of adjacent devices  520  and  530 . Non-transparent portions  516 ,  526 ,  536 ,  546  are disposed along linear bus bar  515  and may connected thereto for powering the array. 
       FIG. 6  is a schematic view of array  60  showing two rows of overlapping packages  610 ,  620 ,  630 ,  640 ,  650 ,  660 ,  670 , and  680  oriented with non-transparent portions  616 ,  626 ,  636 ,  646  of the edge seal zone of each device in the first row linearly aligned, and non-transparent portions of the edge seal zone of each device in the second row (not shown) linearly aligned with each other. Electroactive area  614  of the first device in the first row, device  610 , is overlapped by transparent portion  622  of the edge seal zone of adjacent device  620 . Transparent portions  632  and  642  of the edge seal zones of devices  630  and  640  in the row overlap electroactive areas  624  and  634  of adjacent devices  620  and  630 . Electroactive area  654  of the first device in the second row, device  650 , is overlapped by transparent portion  662  of the edge seal zone of adjacent device  660 . Transparent portions  672  and  682  of the edge seal zones of devices  670  and  680  in the row overlap electroactive areas  664  and  674  of adjacent devices  660  and  680 . Electroactive areas  614 ,  624 ,  634  and  644  of devices  610 ,  620 ,  630  and  640  in the first row overlap non-transparent portions (not shown) of the edge seal zone of each device in the second row, and transparent portions  618 ,  628 ,  638 , and  648  of the edge seal zones of devices  610 ,  620 ,  630 , and  640  overlap non-transparent areas (not shown) of adjacent devices  650 ,  660 ,  670 , and  680 . Non-transparent portions  616 ,  626 ,  636 ,  646  of devices  610 ,  620 ,  630 , and  640  in the first row are disposed along linear bus bar  615  and may be connected thereto in order to power the row, and non-transparent portions of the edge seal zone of each device in the second row are disposed along linear bus bar  625  and may be connected thereto in order to power the row. 
       FIG. 7  is a schematic view of array  70  showing overlapping packages  710 ,  720 ,  730 , and  740  arranged in one row and oriented with non-transparent portions (not shown) of the edge seal zone of each device aligned parallel to non-transparent portion  716 . Electroactive area  744  of the first device from the right in the row, device  740 , is overlapped by transparent portion  732  of the edge seal zone of adjacent device  730 . Transparent portions  712  and  722  of the edge seal zones of devices  710  and  720  in the row overlap electroactive areas  724  and  734  of adjacent devices  720  and  730 . Electroactive areas  714 ,  724  and  734  overlap non-transparent portions (not shown) of the edge seal zone of devices  720 ,  730  and  740 , which are aligned parallel to non-transparent portion  716  of device  710 . 
       FIG. 8  is a schematic view of array  80  showing two rows of overlapping packages  810 ,  820 ,  830 ,  840 ,  850 ,  860 ,  870 , and  880  oriented with non-transparent portions (not shown) of the edge seal zone of each device in the first row aligned parallel to non-transparent portion  816 , and non-transparent portions of the edge seal zone of each device in the second row (not shown) parallelly aligned. Electroactive area  844  of the first device from the right in the first row, device  840 , is overlapped by transparent portion  832  of the edge seal zone of adjacent device  830 . Transparent portions  812  and  822  of the edge seal zones of devices  810  and  820  in the row overlap electroactive areas  824  and  834  of adjacent devices  820  and  830 . Electroactive area  884  of the first device from the right in the second row, device  880 , is overlapped by transparent portion  872  of the edge seal zone of adjacent device  870 . Transparent portions  852  and  862  of the edge seal zones of devices  850  and  860  in the row overlap electroactive areas  864  and  874  of adjacent devices  860  and  880 . Electroactive areas  814 ,  824 , and  834  of devices  810 ,  820 , and  830  in the first row overlap non-transparent portions (not shown) of the edge seal zone of adjacent devices  820 ,  830 , and  840  in the same row, and transparent portions  858 ,  868 ,  878 , and  888  of the edge seal zones of devices  850 ,  860 ,  870 , and  880  in the second row overlap non-transparent areas (not shown) of adjacent devices  810 ,  820 ,  830 , and  840  in the first row. Non-transparent portions are connected to a power source via electrical leads. 
       FIG. 9  is a plan view of package  90  having transparent edge seal zones  912 , electroactive area  924  and non-transparent edge seal zones  926  and  928 . Edge  926  contains the anode and cathode (not shown) of the device, conductive areas  903 , and optional conductive tab contacts  921 . Edge  928  contains the anode (not shown) and a conductive layer disposed thereon for enhancing conductivity. Conductive areas  903  and the conductive layer of edge  928  are shown as a continuous layer in the figure, but in some embodiments, the conductive areas/layer may include one or more thin conductive lines for enhancing conductivity of the anode, and connected to a power source. Electric leads  923  may be connected between conductive tabs  921  and a power supply. Depending on the connector mounting scheme, the design of the contacts may vary. The figure depicts ribbon-type conductors that may be attached to the cathode and anode metal using a conductive adhesive. Whereas the conductive tabs may extend inward between the backsheet and the substrate, in some embodiments, it may be preferable to place them in an outboard configuration so that they do not interfere with sealing the edge. In other embodiments, the conductive tabs may be printed as a thin metal layer on the backsheet. Contact to the anode and cathode may be made with conductive adhesive. In addition, it may be desirable to add another layer on top of the electrode metallization adjacent to the backsheet that is resistant to attack from the environment, especially in the edge region that may remain exposed after backsheet application. This could in the form of a non-corroding metal, or it could be a UHB or other organic or inorganic barrier layer. 
       FIG. 10  is a schematic view of array  100  showing overlapping packages  1010 ,  1020 ,  1030 , and  1040  arranged in one row and oriented with non-transparent portions of the edge seal zone of each device parallelly aligned. Non-transparent portions of the edge seal zone of devices  1020 ,  1030 , and  1040  are arranged parallel to exposed non-transparent portion  1016  of device  1010 . Electroactive area  1044  of the first device from the right in the row, device  1040 , is overlapped by transparent portion  1032  of the edge seal zone of adjacent device  1030 . Transparent portions  1012  and  1022  of the edge seal zones of devices  1010  and  1020  in the row overlap electroactive areas  1024  and  1034  of adjacent devices  1020  and  1030 . Electroactive areas  1014 ,  1024  and  1034  overlap non-transparent portions (not shown) of the edge seal zone of devices  1020 ,  1030  and  1040 , which are aligned parallel to non-transparent portion  1016  of device  1010 . Non-transparent portions  1018 ,  1028 ,  1038 , and  1048  of devices  1010 ,  1020 ,  1030 , and  1040  are linearly aligned. 
       FIG. 11  is a schematic view of array  110  showing two rows of overlapping packages  1110 ,  1120 ,  1130 , and  1140  oriented with non-transparent portions (not shown) of the edge seal zone of each device in the first row, and non-transparent portions  1158 ,  1168 ,  1178 , and  1188  of devices  1150 ,  1160 ,  1170 , and  1180  in the second row, aligned orthogonally to non-transparent portions  1116  and  1156  of devices  1110  and  1150 , respectively. Electroactive area  1144  of the first device from the right in the first row, device  1140 , is overlapped by transparent portion  1132  of the edge seal zone of adjacent device  1130 . Transparent portions  1112  and  1122  of the edge seal zones of devices  1110  and  1120  in the row overlap electroactive areas  1124  and  1134  of adjacent devices  1120  and  1130 . Electroactive area  1184  of the first device from the right in the second row, device  1180 , is overlapped by transparent portion  1172  of the edge seal zone of adjacent device  1170 . Transparent portions  1152  and  1162  of the edge seal zones of devices  1150  and  1160  in the row overlap electroactive areas  1164  and  1174  of adjacent devices  1160  and  1180 . Electroactive areas  1114 ,  1124 , and  1134  of devices  1110 ,  1120 , and  1130  in the first row overlap non-transparent portions (not shown) of the edge seal zone of adjacent devices  1120 ,  1130 , and  1140  in the same row, and electroactive areas  1154 ,  1164 ,  1174 , and  1184  of devices  1150 ,  1160 ,  1170 , and  1180  in the second row overlap non-transparent areas (not shown) of adjacent devices  1110 ,  1120 ,  1130 , and  1140  in the first row. Non-transparent portions  1158 ,  1168 ,  1178 , and  1188  of devices  1150 ,  1160 ,  1170 , and  1180  remain exposed. Non-transparent portions are connected to a power source via electrical leads. 
     While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.