Patent Application
20130207094
The invention relates to a process for making one or more electrical connections to an organic light-emitting diode containing encapsulated device, and to such a device.
An organic light-emitting diode (OLED) containing device conventionally comprises:
As is known, OLEDs are electronic components that are very sensitive to oxygen, liquid water and water vapor. Thus, OLEDs are furthermore provided with one or more encapsulation layers covering the organic light-emitting system.
Moreover, OLEDs are conventionally provided with conductive electrical connection elements in order to supply power to the electrodes.
Currently, this connection is made to exposed parts of the electrodes, parts that are not covered by the encapsulation.
Thus, patent EP 030 779 39 describes an OLED lamp (see
Thus, to allow these connections to be made, the encapsulation layers are deposited through a mask protecting the specified connecting zones, thereby making the process more complicated and/or laborious (mask placement, removal, etc.).
In addition, in shadowed regions (mask edges) defects may appear that compromise the encapsulation.
Document WO 2008/103558 describes an OLED device (in relation to
It is even possible to simplify the wiring and/or improve the electrical reliability of the OLED device obtained.
The objective of the invention is thus to provide an organic light-emitting diode containing device encapsulated by one or more layers, and with wiring that is simpler and more reliable, especially an OLED device that is more compatible with industrial requirements (production yield, ease of production, etc.) even for large areas.
For this purpose, the invention firstly provides a process for making one or more electrical connections to an organic light-emitting diode containing encapsulated device comprising, in this order:
The process furthermore comprises, after encapsulation of the device:
This process is simple and very inexpensive to implement. It makes it possible to define and incorporate, simply and economically, the lower connection zone and/or the upper connection zone in the encapsulated OLED device without making holes in the encapsulation beforehand, these holes conventionally being produced by photolithography (using a mask) before deposition of the encapsulation.
The process according to the invention, by making steps of placing and removing a mask or masks redundant, saves labor and has a smaller number of steps that are production yield critical, while improving the reliability of these OLED devices over time.
The process according to the invention is also more tolerant of alignment errors. Since the connection is made a posteriori, the number of alignment errors, especially alignment relative to the mask aperture, is reduced.
Thus, firstly, the invention allows leakage current to be reduced by a substantial amount by limiting the risk of surface contamination by the mask-handling tool.
In addition, since the mask is often placed automatically in the deposition tool, additional investment related to this automatic control is required. The mask is also a device that can be reused many times but that requires a special cleaning procedure, which is unnecessary with the process according to the invention.
Moreover, sometimes, during the deposition steps for depositing the various layers, after the mask has been applied, the latter expands at a different rate to the substrate under the effect of heating, so much so that, during the application of the one or more electroconductive layers forming the upper electrode, the latter may make contact with the lower electrode, thus creating, by misalignment, a short-circuit of greater or lesser extent.
Next, during removal of the mask, the layers that were deposited on the latter have a tendency to disintegrate and then to redeposit on the multilayer in the form of dust, thus causing the OLED device to malfunction. For this reason, in order to prevent such a drawback, removal of the mask is conventionally accompanied by a suction, this operation thus requiring two operators.
The present invention furthermore gives designers greater freedom when designing OLED devices since the connection zones of these devices may be shaped and arranged on the electrodes depending on the desired illumination profile to be obtained.
During the US soldering (sometimes confused with ultrasonic welding) the one or more layers of the electrode in question, about a few nm to a few hundred nm in thickness, will also generally be (partially or completely) pierced. The solder and electrode are then electrically connected laterally, via the edges.
The application of the ultrasound is essential if the solder is to bond to the dielectric substrate, in particular when it is made of glass.
It may be envisioned to use separate methods to form the electrical connection zones of the two electrodes. However, it is preferable to use ultrasonic soldering for both electrodes.
The process according to the invention may furthermore make redundant production of internal current leads, i.e. leads under the encapsulation layer and adjacent the electrodes, such as described in document WO 2008/103558, or even production of current leads in an encapsulation-free border zone.
A known current lead used in OLEDs takes the form of a strip (busbar) on the electrode in question, serving to uniformly spread current, and especially comprising:
This step of forming one or more current leads may be simplified. For example: the step of forming a current lead for the lower electrode, subjacent the encapsulation layer, may be coupled with (especially concomitant with) the step of forming the lower electrode, and comprise the deposition of one or more materials for the lower electrode.
Thus one or more current leads are produced with the very same deposition used to deposit the one or more materials for the lower electrode—especially a mesh electrode as, for example, described in document WO 2010/034944—as follows:
This mesh electrode may furthermore be smoothed by filling the space in the cells of the mesh and by adding a smoothing electroconductive coating in the cells and over the strands of the mesh (optionally identical to the filling material), especially such as described in document WO 2009/071821.
Alternatively, or cumulatively, the connection process according to the invention may preferably be:
Moreover, preferably, the solder for the lower electrical connection may be sufficiently extensive to spread current (therefore forming a partially external current lead zone for the lower electrode) and/or the solder for the upper electrical connection is sufficiently extensive to spread current (therefore forming a partially external current lead zone for the upper electrode).
The US soldering zone may be formed by one or more soldering points, especially along a given electrode edge, or may be continuous, forming a strip for example.
The upper connection zone (which is optionally a US soldering zone) may be an edge adjacent or opposite the lower connection zone (which is optionally a US soldering zone).
The US solder is generally an alloy solder, most often (mainly) a tin-based alloy solder.
Once the US soldering has been carried out, the electrode in question can be easily connected to an external connecting element. The electrical connection between the connection element and the electrode in question may be ensured simply by contact. However, apart from the fact that this type of electrical contact is far from perfect, this contact method risks perforation of the electrode, and therefore degradation of the functionality of the glazing unit, during use.
Also preferably, the process according to the invention may comprise connection of an external connecting element for the lower electrode especially by heating the encapsulated device in the lower electrical connection zone after the ultrasonic soldering or during the ultrasonic soldering for the lower electrical connection zone and/or it may comprise connection of an external connecting element for the upper electrode especially by heating the encapsulated device in the upper electrical connection zone after the ultrasonic soldering or during the ultrasonic soldering for the upper electrical connection zone.
It is thus possible to easily and reliably connect the electrode in question to an external connecting element (which, preferably, is flat and protrudes from the substrate).
The external electrical connection element is especially chosen from at least one of the following electrical connection means:
The external electrical connection means may be provided, on its surface, with a solder (tinned copper, etc.) in order to aid its attachment.
The OLED device according to the invention may:
In a first configuration, the lower connecting solder does not pass through the one or more materials of the upper electrode in the lower electrical connection zone (and preferably does not pass through the internal element connected, in particular, to current leads, in particular of the wire type).
For example, the deposition of the one or more layers for the upper electrode may leave exposed the first edge optionally coated with the one or more organic light-emitting layers, especially via masking of the first edge.
Therefore, a mask is used in deposition of the upper electrode, in particular if the deposition is a vacuum deposition, for example evaporation in which a magnetic mask (Ni, etc.), held by magnets on the opposite face of the substrate, may be used, in contrast to deposition by magnetron sputtering.
Such depositions are more easily produced if the upper electrode is reflective i.e. often thick, especially a monolayer, for example of aluminum.
In a second configuration, the lower connecting solder passes through the one or more materials of the upper electrode in the lower electrical connection zone.
For example, the layer deposition for the upper electrode covering said first edge (and the one or more subjacent organic layers), the process may comprise, preferably before the US soldering in the lower electrical connection zone and especially before encapsulation, a selective local structuring, without (post-) masking, in the zone of the first edge, which divides said layer deposition for the upper electrode into an electrically inactive zone and into said upper electrode (and optionally dividing the subjacent organic layers), this structuring optionally extending as far as the lower electrode (non-inclusively or at least partially in order to preserve its electroconductive function), and preferably the process comprises filling the structured zone with an insulating material.
This may especially be achieved by laser ablation, by adjusting the power (in order to control the ablation depth) and the wavelength depending on the absorption of the layers.
It is also possible to use chemical etching, especially chemical screen printing, or mechanical cutting.
In this first configuration, the lower electrode may especially be reflective, and the upper electrode transparent.
Moreover, the layer deposition for the, especially transparent, lower electrode, for example by magnetron sputtering, may cover the zone intended to be the adjacent zone, of upper connection.
The process may then comprise, before the layer deposition for the upper electrode (and preferably with the organic layer deposition) a local structuring of said one or more layers of the lower electrode (optionally of the organic layers) without (post-) masking:
Furthermore, the process may preferably comprise filling the zone thus structured (especially by screen printing) with an insulating material that is, in particular, thicker and that extends over one edge of the electrode.
Naturally, it may be preferable to choose to use, for the upper electrode, the same selective local structuring technique used for the local structuring of the lower electrode, laser cutting for example.
After the contacts have been fitted on the electrodes, the OLED device may be covered with an electrically insulating and/or mechanically protecting element that may be transparent if necessary.
For example, after the one or more US soldering steps, a lamination is carried out, if necessary, with an intermediate material (a thermoplastic sheet for example) and a counter substrate, especially a glass counter substrate.
The external electrical connection means may thus be incorporated on one side of a lamination interlayer.
By way of common lamination interlayers, mention may be made of flexible polyurethane (PU), a plasticizer-free thermoplastic such as ethylene vinyl acetate (EVA) or polyvinyl butyral (PVB), or a polyethylene acrylate copolymer, for example sold by DuPont under the name Butacite or sold by Solutia under the name Saflex. These plastics for example are between 0.2 mm and 1.1 mm in thickness, especially being between 0.38 and 0.76 mm in thickness.
By way of other plastic materials, polyolefins, such as polyethylene (PE), polypropylene (PP), PEN or PVC, or ionomer resins may be used.
The invention also relates to an organic light-emitting encapsulated device with one or more electrical connections, especially such as manufactured using the process described above, comprising, in this order:
This solder pad makes contact with the upper electrode (preferably from the top though even via the edge face) or with the surface of the one or more adjacent electroconductive layers electrically connected with the upper electrode in said zone.
The OLED device may furthermore be envisioned with one or more of the following features:
The electrode may be obtained by a deposition or a succession of depositions carried out using a vacuum technique such as sputtering or optionally magnetron sputtering.
For a (semi)transparent electrode, any type of transparent electroconductive layer may be used, for example layers such as “TCOs” (transparent conductive oxides). The electrodes may especially be electroconductive layers chosen from metal oxides, especially the following materials:
Metal layers called “TCCs” (for transparent conductive coatings) may also be used, for example made of Ag, Al, Pd, Cu, Pd, Pt, In, Mo, Au.
Lastly, use may be made of a silver containing multilayer: electrical layer(s)/Ag/dielectric layer(s)/Ag/dielectric layer(s), such as described in documents WO 2008/059185, WO 2009/083693.
For a reflective electrode, one or more metal layers “TCCs” (transparent conductive coatings), for example made of Ag, Al, Pd, Cu, Pd, Pt, In, Mo or Au, may be used.
The surfaces of the electrodes are not necessarily continuous.
The encapsulation produced more particularly allows the one or more silver layers to be protected from environmental corrosion.
Encapsulation layers, preferably having a total thickness larger. than 100 nm and smaller than 3 pm, may be chosen from mineral layers (Al2O3, Si3N4, SiO2, AlN, etc.) optionally with addition of polymer layers (parylene, polyimide, etc.).
The lower electrode, if transparent, may be a mesh electrode, especially such as described in document WO 2008/132397 with, as has already been seen, preferably an unapertured border for the current lead.
Of course, the location of the lower connection zone, generally along one edge of the substrate (and/or of the active OLED zone) may vary and may especially be:
Of course, the location of the upper connection zone, generally along one edge of the substrate (and/or of the active OLED zone) may vary and may especially be:
Lastly, the upper connection zone may be on an edge adjacent or opposite the edge of the lower connection zone.
Furthermore, depending on the location of these connection zones, appropriate modifications are made to:
The OLED device encapsulated according to the invention may furthermore be subdivided into a plurality of organic light-emitting zones, for example such as described in document WO 2008/119899.
The encapsulated OLED device according to the invention may then be equipped with:
Each electrode zone may have a geometric shape (square, rectangle, circle, etc.) and may especially be unapertured or a mesh.
The electrodes zones within a row may have substantially the same shape and/or size. In the direction perpendicular to the row, the lower electrode zone may be any size, for example at least 3 cm or 5 cm in size, or even about 10 cm in size (10 cm or more).
The lower electrode may be formed from a single row of lower electrode zones, and, in the direction perpendicular to this row, the upper electrode and the light-emitting layer may be discontinuous in order to form a plurality of parallel rows. Etching of the lower electrode is then preferably carried out (one line) perpendicular to the orientation of the rows of upper electrodes. From one row to another, the zones may be shifted, for example so as to be staggered.
For series connection of the row of lower electrode zones, the light-emitting zones are shifted relative to the lower electrode zones in the direction of this row, and the upper electrode zones are shifted relative to the light-emitting zones in the direction of this row.
It will be recalled that, in series connection, the current passes from an upper electrode zone to the adjacent lower electrode zone.
This type of connection guarantees the uniformity of the illumination over large areas, a satisfactory fill factor, reliability, and is inexpensive and easy to manufacture, especially on an industrial scale.
Advantageously, the OLED device may also be organized in a plurality of substantially parallel light-emitting rows, these rows preferably being spaced apart a distance of less than 0.5 mm, each row being capable of being connected in series.
From one row to another, the electrode zones may be of substantially different shape and/or size.
These rows may preferably be electrically isolated from one another by an isolating resin, especially deposited by screen printing or inkjet printing.
The intrarow spaces and/or the spaces between rows may preferably be manufactured by laser or by chemical screen printing with an etching paste.
The distance between the light-emitting zones of separate rows may be larger than the distance between the zones in a given row, preferably from 100 μm, especially between 100 μm and 250 μm.
Each row may thus be independent. If one of the zones in each row malfunctions, the entire row nevertheless continues to function and adjacent rows remain intact.
Alternatively, the lower electrode may comprise a plurality of rows of lower electrode zones and the light-emitting layer and the upper electrode reproduce these rows (shifted in the direction of the rows). Various types of connection are therefore possible in the case of a plurality of rows:
For a given (single) row connected in series (typically oriented parallel to two opposite edges of the substrate), two US soldering operations may be carried out:
For a plurality of given rows connected in series (each one typically being oriented parallel to two opposite edges of the substrate), it is possible to carry out two US soldering operations per row, as described above, for a series connection.
For a plurality of given rows connected in series/parallel (typically each one in a given direction parallel to two opposite edges of the substrate), two US soldering operations may be carried out:
Moreover, the substrate may preferably be flat. The substrate may be transparent (in particular for emission through the substrate).
Its main faces may be rectangular, square, or even any other shape (round, oval, polygonal, etc.). The substrate may be a substantial size, for example having an area larger than 0.02 m2 or even 0.5 m2 or 1 m2, with an electrode occupying substantially this entire area (all but excepting the structured zones).
The substrate may be rigid, flexible or semiflexible.
The substrate may be made of a plastic, for example polycarbonate, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polymethyl methacrylate (PMMA).
The substrate is preferably made of glass, especially soda-lime-silica glass.
OLEDs are generally categorized into two large families depending on the organic material used.
If the organic light-emitting layers are polymers, PLEDs (polymer light-emitting diodes) are spoken of. If the light-emitting layers are small molecule layers, SM-OLEDs (small-molecule organic light-emitting diodes) are spoken of.
An example of a PLED consists of the following multilayer:
The upper electrode may be a Ca layer.
Generally, the structure of an SM-OLED consists of a stack of a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer.
An example of a hole injection layer is copper phthalocyanine (CuPC), the hole transport layer may for example be N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine (α-NPB).
The emissive layer may for example be a layer of fac-tris(2-phenylpyridine)iridium [Ir(ppy)3]-doped 4,4′,4″-tri(N-carbazolyl)triphenylamine (TCTA).
The electron transport layer may be composed of aluminum tris-(8-hydroxyquinoline) (Alq3) or bathophenanthroline (BPen).
The top electrode may be a layer of Mg/Al or LiF/Al.
Examples of organic light-emitting multilayers are for example described in document U.S. Pat. No. 6,645,645.
The OLED device according to the invention may moreover incorporate any functionalization(s) known in the glazing field. Among these functionalizations, mention may be made of: hydrophobic/oleophobic layers, hydrophilic/oleophilic layers, photocatalytic antifouling layers, reflective multilayers reflecting thermal (solar control) or infrared (low-E) radiation, antireflection multilayers, and/or a reflective layer providing a mirror effect.
The OLED device according to the invention may form (whether alternatively or cumulatively) a decorative or architectural illuminating system, a signaling or display system—for example for displaying a graphic, logo or alphanumeric sign—whether for indoor or outdoor use.
The OLED device according to the invention may be intended to be used in the construction of buildings, optionally in a double glazing unit, forming curtain walling, especially providing illumination, or a (door) window, especially providing illumination.
The OLED device according to the invention may be intended for use in a means of transportation, as a rear window, a side window, or as an illuminating automobile roof, as a rear view mirror, part of a windshield, a windshield, or in any other land-based, sea-based or air-based vehicle, especially as a porthole or in a cockpit.
The OLED device according to the invention may be intended for use in urban furniture such as bus shelters, in a display cabinet, in a jeweler's display case, a shop window or in a greenhouse.
The OLED device according to the invention may also be intended for interior furnishings, especially being a shelf element, a mirror, an illuminating panel for an item of furnisher, an aquarium wall, a floor tile, in particular an illuminating floor tile, or for use in wall or floor or ceiling coverings.
The present invention will be better understood on reading the detailed description below of exemplary nonlimiting embodiments, and of the following
a is a schematic partial top view of the OLED encapsulated device in
b is a schematic partial top view of a variant of the OLED encapsulated device in
For the sake of clarity, the various elements of the figures have not been drawn to scale.
The OLED encapsulated device 100 emits through the substrate, and comprises:
The passivating resin 71 is for example an acrylic or polyamide resin, for example the resins Wepelan SD2154 E and SD 2954.
The encapsulation 5 also covers border zones 51, 52 of bare glass, along the first and second lateral edges of the glass 1.
The glass sheet 2 is about 0.7 to 10 mm in thickness, is optionally extraclear glass, and may have an area of about 1 m2. Its edge face 21 is preferably smooth. The sheet 2 is optionally thermally or chemically tempered and/or curved.
The lower electrode 2 is, for example, a silver containing thin-film multilayer or even a, preferably planarized, metal mesh.
The organic light-emitting system (OLED) 3 is for example formed from:
The organic light-emitting system 3 may emit polychromatic radiation, which is to say white light.
The reflective upper electrode 4 is made of metal and is especially based on silver or aluminum. For the electrical connections, the OLED device 100 comprises:
The solder pads 61 and 62 protrude from the encapsulation 5. The solder is a tin-based alloy.
Two external connecting elements 81 and 82, extending beyond the lateral edges of the substrate, are respectively soldered directly to the solder plots and 62, US vibration not being required. These solder operations are carried out by local heating of the US solder pads 61, 62, for example with a laser or by induction.
As
As
The other solder pad (not shown) may extend along the opposite lateral edge and take the form of regularly distributed localized spots of solder for better spreading of the current, and the external connecting element may be a series of tinned copper wires fastened to these localized spots of solder.
The OLED device 100 is produced in the following way:
The light-emitting encapsulated device 200 firstly differs from the first device 100 in that it furthermore comprises an (EVA, PVB, PU, or silicone, etc.) lamination interlayer 9 or a coat of resin and a glass counter substrate 1′ thereby adding further protection to the encapsulation 5.
The lamination interlayer 9 for example bears external connecting elements 71, 72.
The light-emitting encapsulated device 200 then differs from the first device 100 in that the organic light-emitting system 3 extends into the lateral edge zone i.e. the lower connecting zone 21. Thus, the US solder pad 61 also passes through this system 3 in this zone 21.
The light-emitting encapsulated device 200 lastly differs from the first device 100 in that the upper electrode 4 extends further and covers all the lower electrode materials in the adjacent zone 22, i.e. in the upper connecting zone. Thus the US solder pad 62 also passes through the upper electrode 4 in this zone 22.
The light-emitting encapsulated device 300 differs from the first device 100 above all in that the organic light-emitting system 3 and the upper electrode 4′ (substantially) cover the lower electrode 4 in the lateral edge zone 21 i.e. the lower connecting zone 21. Thus, the lower connecting US solder pad 61′ also passes through these layers.
Furthermore, to prevent short-circuits, the device 300 comprises an electrically isolating zone 70 that is more central than this solder pad 61′, which zone at least separates the upper electrode 4, and preferably also the organic light-emitting system 3, into two zones. Preferably, this selective electrical isolation zone is produced by laser cutting, and preferably before encapsulation 5. As a variant, this selective isolation zone is produced by laser cutting after encapsulation and lamination is carried out.
As for the lower electrode 2, it remains intact or sufficiently well preserved by this structuring to conduct electricity in this region.
This electrically isolating zone 70 may be filled with a passivating resin, for example identical to the resin 71, or even filled by the encapsulation. This electrically isolating zone 70 is in any case covered by the encapsulation 5.
In this embodiment, it may also be preferable to use a laser to form the isolation zone 7.
As shown in
The light-emitting encapsulated device 300 may optionally differ from the first device 100 in that it also (even only) emits via its frontside (via the upper electrode 4 and encapsulation layer 5). Thus, the upper electrode 4′ and the encapsulation 5 are transparent and the lower electrode 1′ is reflective (or even semireflective).
The solder pads 61′, 62′ each lie along a lateral and longitudinal edge, at right angles.
The isolation zones 70 and 7 are modified accordingly.
There are two illuminating OLED zones, and for each of these:
To shorten manufacture, it is preferable to simply form two electrical isolation lines 7 serving for the two active zones.
The OLED devices described above have many applications.
The light-emitting devices 100 to 300 may be intended for architectural applications, thus forming illuminating curtain walling, windows or glass doors.
The devices 100 to 300 may be intended for use in a means of transportation, as an illuminating rear window, an illuminating side window, or as an illuminating automobile roof, as a rear view mirror, part of a windshield, or in any other land-based, sea-based or air-based vehicle, especially as a porthole or in a cockpit.
The light-emitting devices 100 to 300 may be intended for use in urban furniture such as bus shelters, in a display cabinet, in a jeweler's display case, in a shop window, in a shelf element, in an aquarium wall or in a greenhouse.
The light-emitting devices 100 to 300 may be intended for interior furnishings, forming an illuminating panel for an item of furnisher, or an illuminating floor tile, especially a glass floor tile, or may be intended for use in wall or floor coverings, as illuminating ceiling tiles or as a splashback for a kitchen or bathroom.
The light-emitting devices 100 to 300 may provide illumination for a decorative, architectural, signaling or display purpose.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1057746 | Sep 2010 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR2011/052209 | 9/23/2011 | WO | 00 | 4/30/2013 |
