Electroluminescent device with improved resolution and reliability

Abstract

An electroluminescent display device is disclosed, comprising a plurality of pixels deposited on a substrate, each pixel being formed by one or more basic emission regions, two adjacent basic emission regions being separated by a space having a vertical wall, each basic emission region comprising a base electrode directly deposited on the substrate, and each basic emission region further comprising an OLED stack, the OLED stack comprising an electroluminescent layer deposited on the base electrode, and the device comprising a common electrode deposited on top of the OLED stack, wherein: two adjacent base electrodes belonging to two adjacent basic emission regions are separated by a filling element having an insulating surface, the filling element being arranged in the space between the basic emission regions, the insulating surface covering the surface of the base electrode in the space between the adjacent base electrodes and electrically insulating the adjacent base electrodes from each other; at least the surface of the filling element having an insulating surface that is in contact with the base electrode is made of an insulating material.

Description

[0001] This application is a divisional application of the patent application with application number 2019800246464, application date April 4, 2019, and invention name “Electroluminescent device with improved resolution and reliability”. Technical Field

[0002] The invention relates to the field of optoelectronic devices and components, more precisely to electroluminescent devices of the OLED (Organic Light Emitting Diode) type. More specifically, the invention relates to improving the display color range and the reliability of the resolution of OLED type display screens. It relates to simple OLED devices and tandem OLED devices. Background Art

[0003] Organic electroluminescent devices have aroused considerable interest in flat screen and thin screen lighting devices. The working life of OLED devices decreases with the increase of current density or brightness, because a large number of holes and electrons passing through the organic layer will cause electrochemical secondary reactions of organic components. A specific method to solve this problem is to use two or more superimposed OLED diodes (so-called tandem devices), the purpose of which is to achieve a longer working life at high brightness. In the tandem OLED structure, multiple electroluminescent units are stacked in series through interconnecting layers such as transparent conductive layers (TCL) or charge generation layers (CGL). In addition, the electron injection layer (EIL) also plays an important role in reducing the electron injection barrier of the TCL or CGL in the first electroluminescent unit. At the same current density, the tandem OLED with two superimposed electroluminescent units can show double brightness compared to a single electroluminescent device. Therefore, the efficiency and working life of the tandem OLED can be improved compared to the efficiency and working life of a conventional OLED with a single unit.

[0004] OLED displays typically include a matrix structure of individual pixels controlled by a grid of vertical and horizontal conductive traces; this structure allows the pixels to be individually addressed. Figure 1, which will be explained below. In a color screen, each pixel is subdivided into sub-pixels of various colors (usually three or four, including red, green and blue), which cooperate to emit light points (pixels) of the desired color. Figure 3 (a) shows a cross-section of such a screen. On top of the electrodes of the sub-pixels, an OLED stack is deposited, which covers the entire surface of the matrix and, in this example, emits white light. In this case, the RGB (red-green-blue) or RGBW (red-green-blue-white) primary colors of the sub-pixels are produced by color filters located above the OLED stack. Another way to produce primary colors is to construct the OLED layers into sub-pixels with different emission colors. Since the method of constructing OLED layers is quite complex and the resolution that can be obtained is very limited, it is even preferred in this case to keep the most common layers (i.e. the layers covering the entire surface of the matrix), usually the layers that transport charge carriers, and only construct the light-emitting layers. However, in both of the above cases, it is observed that adjacent pixels or sub-pixels can interact through capacitive coupling or through stray currents that pass through the common conductive layer of the OLED stack, in particular.

[0005] An example of such stray currents is shown in FIG. 3( b ), which will be explained below. Such undesired interactions between adjacent pixels are known to those skilled in the art by the term crosstalk; in the case of color screens, this leads in particular to undesired color changes. Theoretical aspects of the crosstalk phenomenon in OLED devices have been studied for a long time (see, for example, the publication by D. Braun “Crosstalk in Passive Matrix Polymer LED Displays”, which appeared in the journal Synthetic Metals 92, 1998, p. 107-113).

[0006] It is well known that, in the case of single-diode OLED devices, the crosstalk phenomenon is exacerbated in OLED devices with series-connected diodes. The interconnecting layers of the series-connected stacked structure have a rather high conductivity and stray currents are observed in the plane of the layers. This problem becomes more pronounced when the size of the sub-pixels is reduced. In addition to the digital correction of the crosstalk consequences (which amounts to accepting the crosstalk phenomenon and reducing its impact on the image), various methods are known for combating the crosstalk at the source, i.e. for reducing the physical phenomenon at the pixel or sub-pixel level.

[0007] For simple OLED devices, in order to prevent short circuit problems associated with moisture in the encapsulation layer, it is known to separate each pixel so as to isolate them from each other. Document EP2927985 describes such a structure in which each pixel is hermetically sealed and isolated from its adjacent pixels. Many complex method steps are required to manufacture such a structure. It is also known to define the pixel area by auxiliary partitioning elements such as walls, as described in document US9419245. These methods are complex and lead to significant additional costs.

[0008] In view of the above problems, an object of the present invention is to at least partially remedy the shortcomings of the above-mentioned prior art and propose a structure for an OLED display device, which structure can significantly reduce lateral stray current even for pixels of very small size (typically less than 5μm), for structures with very small inter-pixel spacing, or for displays with series diodes.

[0009] Another object of the invention is to propose a method which makes it possible to limit stray currents between pixels for a micro-electroluminescent device. Summary of the invention

[0010] The present invention is applicable to an electroluminescent display device, which includes a plurality of pixels deposited on a substrate, each pixel being formed by one or more basic emission regions, wherein each basic emission region includes a base electrode deposited on the substrate and an electroluminescent layer deposited on the base electrode, and the device includes a common electrode deposited on the electroluminescent layer.

[0011] According to the first feature of the present invention, two adjacent base electrodes belonging to two adjacent base emitter regions are separated by a filling member having an insulating surface, which fills a region between the adjacent base electrodes and electrically insulates the adjacent base electrodes from each other.

[0012] At least a surface of the filling member having an insulating surface in contact with the base electrode is made of an insulating material; the entire filling member having an insulating surface may be made of an insulating material.

[0013] According to another feature of the invention, the insulating material of the filling element protrudes onto a portion of the surface of the base electrode.

[0014] According to another feature of the invention, a partition is located above the filling element and separates the electroluminescent layers of two adjacent elementary emission regions; this eliminates leakage currents that propagate horizontally to the substrate in the electroluminescent layer.

[0015] A portion of the common electrode is deposited by a conformal deposition technique, preferably by ALD (Atomic Layer Deposition).

[0016] Therefore, a first object of the present invention is an electroluminescent display device comprising a plurality of pixels deposited on a substrate, each pixel being formed by one or more elementary emission regions, each elementary emission region comprising a base electrode deposited on the substrate and an OLED stack comprising an electroluminescent layer deposited on the base electrode. The electroluminescent display device comprises a common electrode deposited on the OLED stack. The electroluminescent display device is characterized in that:

[0017] - two adjacent base electrodes belonging to two adjacent elementary emitter regions are separated by a filling element having an insulating surface, said filling element filling the region between said adjacent base electrodes and electrically insulating said adjacent base electrodes from each other,

[0018] - at least the surface of the filling element having an insulating surface in contact with the base electrode is made of an insulating material;

[0019] A spacer is located above the filling element and separates the electroluminescent layers of the OLED stacks of two adjacent elementary emission zones.

[0020] The common electrode is advantageously deposited by a conformal deposition technique, preferably by ALD (atomic layer deposition) or CVD (chemical vapor deposition), so as to obtain continuity through the partition. The layers of the OLED stack are advantageously deposited by a directional (i.e. non-conformal) deposition technique, such as thermal evaporation, so as to be able to separate them by the partition.

[0021] Advantageously, the insulating material of the filling element protrudes over a portion of the surface of the base electrode.

[0022] In one embodiment, a top electrode extending between two adjacent spacers and bounded by them is deposited between the OLED stack and the common electrode. This top electrode does not have any functional advantage; on the contrary, in the case of an upward emitting device, this top electrode absorbs light. This top electrode may be used to protect the OLED stack during deposition of the common electrode.

[0023] In an advantageous embodiment, this top electrode is absent and the common electrode fulfills the function of an electrode for each elementary emitting region, ie the function of a cathode for a top emitting device or of an anode for an inverted device.

[0024] In one embodiment, a charge carrier injection layer extends between and delimited by two adjacent spacers, being deposited between said OLED stack and said common electrode. This charge carrier injection layer is capable of injecting charge carriers into the OLED stack (electrons in the case of a so-called standard OLED device, or holes in the case of a so-called inverted OLED device, the terms "standard" and "inverted" being defined below) and of protecting the OLED stack during the deposition of the common electrode. This charge carrier injection layer may in particular be made of molybdenum oxide or tungsten oxide, preferably with a thickness between 0.5 nm and 5 nm.

[0025] We state here that those skilled in the art refer to OLED devices as "standard" in which the injection of holes takes place on the near surface of the substrate and the injection of the electrode takes place on the surface opposite to the substrate, while in so-called "inverted" devices, the injection of electrons takes place on the near surface of the substrate and the injection of holes takes place on the surface opposite to the substrate.

[0026] In another embodiment, the filling member having an insulating surface and the spacer constitute a barrier member extending upward from the substrate. The spacer may fill the top of the region between the adjacent base electrodes.

[0027] In another embodiment, the entire filling element having the insulating surface is made of an insulating material. The separator may include the common electrode.

[0028] These embodiments may be combined with each other.

[0029] In all of these embodiments, the display device may include an encapsulation system deposited on top of the common electrode. The encapsulation system may include a polymer layer and an inorganic layer, preferably an oxide. The display device may include an inorganic layer deposited between the common electrode and the polymer layer, preferably an oxide. The display device may include a smoothing layer deposited on top of the common electrode or on top of the encapsulation system.

[0030] The OLED display device according to the invention may comprise a color filter system deposited on the common electrode or preferably on the encapsulation system or even more preferably on the smoothing layer.

[0031] A display device according to the invention may comprise two superimposed OLED stacks, which are then typically separated by a charge generation layer.

[0032] Another object of the present invention is an electroluminescent display device comprising a plurality of pixels deposited on a substrate, each pixel being formed by one or more elementary emission regions, each elementary emission region comprising a base electrode deposited on said substrate and an OLED stack comprising an electroluminescent layer deposited on said base electrode. The electroluminescent display device comprises a common electrode deposited on top of said OLED stack. The electroluminescent display device is characterized in that:

[0033] - two adjacent base electrodes belonging to two adjacent elementary emitter regions are separated by a filling element having an insulating surface, said filling element filling the region between said adjacent base electrodes and electrically insulating said adjacent base electrodes from each other,

[0034] - at least the surface of the filling element having an insulating surface in contact with the base electrode is made of an insulating material,

[0035] A spacer is located above the filling element, separates the electroluminescent layers of the OLED stacks of two adjacent elementary emission zones and fills the top of the area between the adjacent base electrodes.

[0036] The filling element with an insulating surface generally comprises an insulating layer in contact with the adjacent base electrodes, which insulating layer is capable of electrically insulating the adjacent base electrodes from each other; the filling element may include other functional layers, such as a common electrode. The spacer extending in the natural space between two adjacent elementary emitters (which is generally in the form of a trench) generally comprises a smoothing layer (planarization layer) deposited on top of the common electrode; if this smoothing layer is absent, the spacer may comprise an empty space (i.e. air).

[0037] These embodiments may be combined with each other.

[0038] The common electrode is advantageously deposited by a conformal deposition technique, preferably by ALD or CVD. Advantageously, the insulating material of the filling element protrudes over a portion of the surface of the base electrode. The layers of the OLED stack are deposited by a directional deposition technique, for example by thermal evaporation.

[0039] In one embodiment, a top electrode extending between two adjacent spacers and defined by two adjacent spacers is deposited between the OLED stack and the common electrode. The top electrode can be used to protect the OLED stack during the deposition of the common electrode. The top electrode may not be present, then the common electrode performs the function of an electrode for each elementary emission region, i.e., the function of a cathode for a standard device or the function of an anode for an inverted device.

[0040] In a variation of this embodiment, a charge carrier injection layer extends between two adjacent spacers and is bounded by said spacers, being deposited between said OLED stack and said common electrode. This charge carrier injection layer is capable of injecting charge carriers into the OLED stack (electrons in the case of a top-emitting OLED device, or holes in the case of a so-called inverted OLED device) and of protecting the OLED stack when the common electrode is deposited. This charge carrier injection layer may in particular be made of molybdenum oxide or tungsten oxide, preferably with a thickness between 0.5 nm and 5 nm.

[0041] In all of these embodiments, the display device may include an encapsulation system deposited on top of the common electrode. The encapsulation system may include a polymer layer and an inorganic layer, preferably an oxide. The display device may include an inorganic layer deposited between the common electrode and the polymer layer, preferably an oxide. The display device may include a smoothing layer deposited on top of the common electrode or on top of the encapsulation system.

[0042] The OLED display device according to the invention may comprise a color filter system deposited on the common electrode or preferably on the encapsulation system or even more preferably on the smoothing layer.

[0043] A display device according to the invention may comprise two superimposed OLED stacks, which are then typically separated by a charge generation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Figures 1 to 3 illustrate known general aspects of OLED devices and displays. Figures 4 to 8 Various aspects and embodiments of the invention are illustrated; they are not intended to limit the scope of the invention.

[0045] Figure 1 A circuit diagram of a matrix screen of the OLED type of known type is shown.

[0046] FIG. 2 shows three known examples of arrangements of sub-pixels having different colors for forming a pixel capable of displaying a desired color.

[0047] Figure 3 schematically shows a vertical cross section of a pixel in an OLED display according to the prior art, the OLED display having white emission and color filters. Figure 3(a) shows several pixels; Figure 3(b) shows a single pixel with three sub-pixels. Figure 3(c) shows an embodiment of a color pixel without a color filter.

[0048] Figure 4 is a cross-sectional view showing a device according to one embodiment of the present invention.

[0049] Figure 5 is a cross-sectional view showing a structural device according to another embodiment of the present invention.

[0050] FIG. 6 schematically shows a vertical cross section of a tandem device according to the present invention; FIG. 6

[0051] (b) schematically shows a detail of Figure 6(a), ie the stack of organic layers forming the OLED layer. Figure 6(c) shows a variant and Figure 6(d) schematically shows the stack of OLED layers on top of a spacer in this variant.

[0052] Figure 7 and Figure 8 It shows that Figure 4 and Figure 5 A variation of the device shown in FIG.

[0053] The following numerical symbols are used in this manual:

[0054]

[0055]

[0056] DETAILED DESCRIPTION

[0057] Figure 1The circuit of an OLED display 10 of a known type is schematically shown, comprising a pixel matrix unit 12 capable of producing an image, and a control unit 36. The OLED diodes 14 and their control circuits 16 are arranged to form pixels in the pixel matrix unit 12, the pixel matrix comprising rows (horizontal) and columns (vertical). Each circuit 16 controlling the pixel 12 comprises a plurality of thin film transistors 18, 20 (usually using CMOS (complementary metal oxide semiconductor) or TFT (thin film transistor) technology) and a capacitor 22. The control unit 36 ​​controls the control circuits for the rows 30 and the video addressing circuits 32, as well as the power supply circuits 34 for addressing the pixel columns; the power supply circuits 34 provide addressing of the pixel circuits 36 and control the light emission of the OLED diodes 14. The control circuits for the rows are connected to conductive traces 38, addressing the scan lines of the pixel matrix. The control circuits for the rows select the scan lines 38 according to the signals from the control unit 36, and apply voltages to switch on the TFTs 18 located on the selected scan lines 38. The video addressing circuits 32 are connected to conductive traces 40, addressing the columns of the video signals. The video addressing circuit 32 receives the video signal from the control unit 36 ​​and sends a voltage to the video conductive traces 40 of the columns on the conductive traces of the row selected by the corresponding control circuit 30. This voltage signal enters the capacitor 32 through the TFTs 18 of the OLED diodes 14 of the selected pixel row. The control TFTs 20 send a current corresponding to the voltage registered at the OLED diodes 14, and thus, the OLED diodes 14 of the selected row 38 emit light.

[0058] The power circuit 34 is connected to the conductive traces 42 to provide power to the pixel columns; the power circuit 34 provides power to the OLED diodes 14 through the conductive traces 32 and TFTs 20 of the selected pixel rows.

[0059] This principle of addressing OLED diodes to form pixels in a pixel matrix is ​​known per se and can also be applied in a manner known per se to addressing OLED diodes to form sub-pixels in a pixel matrix of a color display device, wherein each pixel comprises a plurality of sub-pixels (typically three or four) having different colors; this will be explained here in conjunction with FIG. FIG. 2( a ), FIG. 2( b ) and FIG. 2( c ) show three examples of geometrical arrangements of these sub-pixels 51 , 52, 53, 54 for forming a pixel 50 capable of displaying the desired colors. In these figures, the sub-pixels are red 51 , blue 52 and green 53 and may additionally include a white sub-pixel 54 as in FIG. 2( c ) for increasing the brightness of the pixel 50. The arrangement in FIG. 2( a ) is known by the abbreviation “RGB stripe” and is the most common. The arrangement in FIG. 2( b ) is known by the abbreviation “RGB quad” and the arrangement in FIG. 2( c ) is known by the abbreviation “RGBW quad”.

[0060] Just refer to Figure 1 The addressing principle described in and 2 is one of the addressing principles that can be implemented for the present invention. The color can be obtained by controlling the color emitted by the OLED layers forming the subpixels or by color filters that modify the white color of the light emitted by the subpixels, as will be explained below with reference to FIG. 3.

[0061] FIG3 schematically shows an OLED microdisplay according to the prior art; it illustrates the problem that the present invention seeks to solve. FIG3( a) shows an overall schematic diagram of the structure of a device 70: one can see a substrate 71 (CMOS or TFT type, addressing circuits and components not shown), control electrodes 72, 73, 74 for sub-pixels separated by filling (“gap-filling”) elements 75, an OLED layer 76 capable of emitting white light, an encapsulation layer 77, a blue filter 91, a red filter 92 and a green filter 93 forming a pixel 90, and a glass wafer 78 as a protective cover. The size of the sub-pixel is typically about 3.5 μm to 5 μm. It should be noted that in such a device according to the prior art, the OLED layer 76 extends over the entire surface of the device.

[0062] Figure 3b An enlarged view of a device similar to that shown in FIG. 3( a ) is shown; the view is limited to a single pixel 90 . The sub-pixels are first defined by electrodes 72 , 73 , 74 that allow them to be addressed individually, and by corresponding color filters 91 , 92 , 93 that modify the light emitted by the OLED layer 76 to a white emission extending over the entire surface of the device. The space between the two electrodes controlling adjacent sub-pixels 72 , 73 can be filled by a filling element 75 , the OLED layer 76 comprising the light-emitting layer 80 itself sandwiched between two charge transport layers 81 , 82 . More precisely, in a typical device, layer 81 comprises a hole injection and transport layer and layer 82 comprises an electron injection and transport layer. However, a so-called “inverted” stack may also be used, in which case layer 82 comprises a hole injection and transport layer and layer 81 comprises an electron injection and transport layer. Layers 81 and 82 may each comprise a single layer that implements the respective two charge injection and transport functions, or a plurality of layers, such as a layer for injection and another layer for transporting the respective charges. A common electrode 85 releases the charges.

[0063] Such a device according to the prior art exhibits stray currents; this is shown in Figure 3(b). This is because, if when a sub-pixel (e.g. 73) is turned on, the main current passes directly (marked by the thick arrow) through the OLED layer in the shortest direction (i.e. perpendicularly with respect to the substrate 71), some of this current propagates along other conductive traces, provided that these conductive traces have a sufficiently low resistivity. Therefore, stray currents are observed, which propagate in the charge transport layer 81, i.e. in the plane of the substrate, and then pass through the OLED layer in the adjacent sub-pixel 72 or 73. This stray current is marked by the dotted arrow. This results in stray light emission in adjacent sub-pixels, which changes the image resolution of the display and reduces the fidelity of its colors. The present invention seeks to provide a device for reducing such stray currents.

[0064] FIG. 3( c ) shows another known type of device in which the color of the pixel 90 is not as Figure 3(a) and 3(b) 3( b) is produced by providing three sub-pixels with electroluminescent layers 95, 96, 97 that directly emit red, blue and green. In this embodiment, each sub-pixel 95, 96, 97 has its own addressing electrode 98a, 98b, 98c, but the first layer 83 for injecting and transporting charges (e.g. holes) and / or the second layer 84 for injecting and transporting charges (e.g. electrons) are shared with the common electrode 99 to simplify the manufacture of the device. The problem of stray currents is the same as described in relation to FIG. 3( b); the contribution of the hole injection and transport layer 83 dominates these stray currents.

[0065] Figure 4 A cross-sectional view of a device 100 according to a first embodiment of the invention is shown. The device comprises a substrate 110 on which are deposited three sub-pixels 121a, 121b, 121c defining a pixel 120. In this example, each sub-pixel represents a basic emission area.

[0066] The substrate 110 is particularly suitable for the device 100, and the substrate 110 may be a substrate for flexible devices made of silicon, glass or plastic material. The substrate 110 may be a CMOS silicon substrate of a known type, which includes circuits for addressing pixels 120 and sub-pixels 121; these aspects of addressing pixels and sub-pixels do not form part of the present invention.

[0067] The basic emission area (sub-pixel) is formed by a plurality of layers, which are listed here, for each sub-pixel, starting with the layer deposited directly on the substrate, which is the electrode 102; the electrodes 102 of these sub-pixels are represented here by the marks 102a, 102b, 102c. On top of the electrodes, the OLED electroluminescent layers are deposited, forming a stack 105, an optional top injection layer 106, and a common conformal electrode 107. Depending on the type of device, a planarization layer 108 and a color filter 109 may be added. More precisely, if a color filter is used, a planarization layer is particularly advantageous in order to avoid light losses. Even in the absence of a filter, the planarization layer may form the basis of an auxiliary packaging system, which may include, for example, an inorganic layer and / or a glass cover. As mentioned above, the need to use a color filter depends on the emission color of the OLED layer forming the sub-pixel.

[0068] Two adjacent basic emission area electrodes (sub-pixels) (for example, electrodes 102a and 102b) are separated by a space 111 referred to herein as a natural space ("gap"), regardless of whether they belong to the same pixel or not. According to a basic feature of the present invention, this natural space 111 is filled with a filling element having an insulating surface 103, referred to as a "gap fill". The filling element having an insulating surface 103 may overlap slightly with the sub-pixel electrode 102 so as to form an edge 112. In a particular embodiment, not only the surface of the filling element 103 but also its entire volume is made of insulating material. It can be prepared, for example, from a composition based on a photosensitive resin (also called a photoresist) or silicon dioxide.

[0069] A spacer 104 with an insulating surface is arranged on top of a filling element 103 with an insulating surface. The walls of the spacer may be vertical. The spacer 104 separates the stack of OLED layers 105 and top injection layer 106 of two adjacent sub-pixels 102. In a particular embodiment, not only the spacer surface but also its entire volume is made of insulating material. It may be made of a photosensitive resin; a negative photosensitive resin may be used, which makes it possible to produce fairly hard or even overhanging side walls. Inorganic dielectric materials may also be used.

[0070] The OLED stack 105 is typically deposited by thermal evaporation. This technique results in a highly directional deposition, so the OLED stack 105 is deposited substantially only on horizontal surfaces and not on the vertical walls of the partitions. The layers of the OLED stack 105 are thus interrupted by the partitions, in other words: the layers of the OLED stack 105 are not continuous through the partitions, they are pixelated.

[0071] The pixelated top injection layer 106 can be replaced by a pixelated top electrode (i.e., each elementary emission region has its own top injection layer or top electrode layer). The top electrode layer can be made of a thin metal such as aluminum (Al), silver (Ag), etc.; the layer can also be deposited by thermal evaporation, in which case it will only be deposited on horizontal surfaces. It should be noted that in the accompanying drawings, when the top electrode layer replaces the top injection layer, the top electrode layer corresponds to the layer identified by the reference numeral 106.

[0072] In order to connect the top injection layer 106 or the top electrode in all pixels, or to connect the last layer of the OLED stack 105 in the case where no top injection layer and pixelated electrode have been deposited, a common additional electrode 107 is required, which is therefore not cut off by the partition 104. This common electrode 107 must be deposited by a technique that allows conformal deposition. It can be made by atomic deposition techniques of thin films (abbreviated ALD, "atomic layer deposition") or by chemical vapor deposition (CVD) of transparent conductive oxides (TCOs). Among the TCOs, mention may be made appropriately of ZnO possibly doped with aluminum, abbreviated AZO (aluminum doped zinc oxide)), SnO2, and indium oxide doped with tin, abbreviated ITO (indium tin oxide); these TCOs are known to those skilled in the art. In the periphery (not shown in the figure), this common electrode 107 is connected to a potential suitable for switching on the OLED 105 when the corresponding pixel electrode 102 is addressed. If the top electrode 106 is deposited by metal evaporation, this electrode will be (more or less) pixelated by the spacers 104 , and in this case a common conformal electrode 107 will form the electrical connection between the small tiles of the top implant layer 106 .

[0073] In this embodiment of the device 101 according to the invention, lateral stray currents in the OLED 105 are completely blocked. Another advantage of this structure is that the conformal common electrode 107, in particular deposited by ALD, is a dense, impermeable film, which acts as an encapsulation and protects the OLED stack 105 from moisture and oxygen. If a failure occurs, for example through a pinhole in the encapsulation, in particular a failure leading to a black spot, this failure cannot extend over a larger surface area, because the spacer 104 and the common electrode 107 isolate each pixel (more or less) hermetically to prevent the diffusion of, for example, water. Therefore, if the failure only affects a sub-pixel, it may not even be visible to the user of the device.

[0074] Figure 4 The embodiment in retains its advantages in the case where the walls of the partition 104 are not completely vertical and do not completely isolate adjacent elementary emission regions: this still significantly increases the lateral resistance between two adjacent OLED stacks 105 and reduces crosstalk phenomena.

[0075] We describe here more precisely the various layers forming the device according to this first embodiment; this description is only an example and does not limit the scope of the invention.

[0076] In a known manner, the substrate 110 with the active matrix can be a CMOS (silicon) substrate comprising transistors in CMOS technology, or a substrate of the glass or plastic type comprising TFT transistors (usually made of a-Si, polysilicon, or metal or organic oxides).

[0077] The pixel electrode 102 is a layer of aluminum (Al) or any other metal, with a typical thickness of 20nm to 1000nm, preferably 100nm to 300nm, optionally covered with a fine layer of TiN or MoO3, or covered with a transparent conductive oxide (abbreviated as TCO), etc. The pixel electrode can be made of TCO, especially in the embodiment of the display emitting downward through a transparent substrate, or in the embodiment of a transparent display emitting upward and downward.

[0078] The size of a display subpixel is typically between 1 μm and 100 μm, preferably between 2 μm and 50 μm, even more preferably between 2 μm and 10 μm. The distance between subpixels is about 0.1 μm and 10 μm, and preferably between 0.2 μm and 1.0 μm.

[0079] The filling element 103 (gap filling) can be a photosensitive resin, epoxy resin, an inorganic dielectric (such as SiO2, Si3N4 or Al2O3). The width of the overlapped portion (edge ​​112) on the electrode is between 0 and 0.5 μm, preferably between 0.05 μm and 0.25 μm.

[0080] The partition 104 may be made of photosensitive resin, epoxy resin, or inorganic dielectric (eg, SiO2, Si3N4, or Al2O3, etc.). The width of the partition is approximately equal to the distance between pixels.

[0081] The OLED stack 105 may be a white OLED, with a single cell or with cells in series or with multiple cells, with a thickness typically between 50 nm and 500 nm, preferably between 80 nm and 250 nm. The OLED stack 105 may emit upward or downward, or on both sides. The deposition of the layers of the OLED stack 105 is performed by a directional method such as thermal evaporation.

[0082] A top injection layer 106 (or top electrode where applicable) is deposited in the space between two adjacent separators 104. If a top electrode is deposited, it can be made of a reflective metal such as aluminum (Al) or silver (Ag) and is typically 25 nm to 100 nm thick for bottom emission and 1 nm to 15 nm thick for top emission or emission on both faces. Deposition can be performed by a directional method such as thermal evaporation.

[0083] In the opposite case, the common electrode 107 deposited on top of the top injection layer 106 or the top electrode (if one of the latter is present) or the OLED stack 105 is typically a transparent conductive oxide such as ZnO, AZO, ITO, SnO2 or others. The common electrode is deposited by a highly conformal deposition method such as ALD, PECVD or other methods. The thickness of the common electrode is typically between 20nm and 300nm.

[0084] The planarization layer (smoothing layer) 108 is typically an organic material (such as a photosensitive resin or epoxy resin) deposited using a solution (by spin coating, spray coating, etc.).

[0085] The color filter 109 is a prior art color filter, for example, made of a colored resin. The color filter can be made of a colored photosensitive resin or a pattern type interference filter or the like.

[0086] Figure 5 A second embodiment of a device according to the invention is shown, the structure repeating most of the components of the first embodiment; Figure 5 Three elementary emission areas 201a, 201b, 201c are shown forming a pixel 213. The device 200 presented in a cross-sectional view comprises a substrate 210 and an electrode 202 of sub-pixels separated by a natural space 211 in the form of a trench. An insulating layer 223 is arranged in this natural space 211, more precisely on the wall of this natural space, with an edge 212 (overlapping) on ​​the electrode pixel 202. The insulating layer 223 fulfils the role of a filling element 203 with an insulating surface.

[0087] The OLED electroluminescent layer 205 forming a stack is deposited on the sub-pixel electrode 202 and the insulating layer 223, followed by a top injection layer 206 or a top electrode (the top injection layer 206 is preferred, but both the top injection layer 206 and the top electrode are optional), a conformal electrode 207, an optional planarization layer (also called a smoothing layer) 208 that fulfills the role of the partition 204, and a color filter 209. In the absence of the smoothing layer 208, the natural space above the common electrode 207 can remain empty, the gap fulfilling the role of the partition 204, or it can be filled by components of the packaging system.

[0088] This embodiment makes it possible to use the natural space between the sub-pixel electrodes 202 with vertical walls as separators. Since the walls of the sub-pixel electrodes 202 are conductive, they must be covered with an insulating layer 223; the insulating layer 223 may also slightly cover the edges of the electrode pixel 202, which reduces the risk of short circuits but increases the complexity of the manufacturing method. The insulating layer 223 may be a dielectric film deposited by a conformal deposition method such as ALD, PECVD, etc., such as a layer of aluminum oxide, silicon dioxide, etc. The insulating layer 223 may use an organic layer, such as a thin layer of photosensitive resin; the insulating layer 223 may generally be manufactured by photolithography, such as Figure 4 A slight return (overlap) is shown to avoid shorting on the edges.

[0089] We describe here more precisely the various layers forming the device according to this second embodiment; this description is only an example and does not limit the scope of the invention.

[0090] The substrate 200 , the pixel electrode 202 , the OLED stack 205 , the optional common electrode 220 , the conformal electrode 207 , the optional planarization layer 208 and the color filter 209 repeat the composition of the first embodiment.

[0091] A thin layer (not shown in the figure) of a conductive material capable of injecting charge carriers (electrons or holes, depending on the geometry of the OLED device) in the organic layer for the OLED is deposited on top of the pixel electrode 202. This thin layer protects the pixel surface when the insulating layer 223 is etched. The thickness of the thin layer is between 1 nm and 50 nm, preferably between 5 nm and 15 nm. The thin layer can be made of TiN, or preferably of a conductive transparent oxide, in particular: tin oxide (SnO2), tin-doped indium oxide (ITO), zinc oxide (ZnO) or aluminum-doped zinc oxide (AZO). If the etching of the insulating layer 223 involves oxygen plasma, the thin layer is preferably made of an oxide.

[0092] To make the insulating layer 223, a thin layer of TiO2 (typically with a thickness between 5 nm and 20 nm) can be deposited over the entire surface of the substrate by ALD. Next, a photosensitive polymer layer of known type (e.g. TEKR-003PM) is deposited by spin coating; for the reference shown, the thickness can be between 0.5 μm and 1 μm. Next, the active surface of the pixel is defined by photolithography; there is a small overlap at the boundaries of the pixel (typically between 0.1 μm and 0.2 μm). The TiO2 is then removed by wet etching using HF; this does not attack the TiN layer and therefore protects the pixel electrode. This choice of material (TiO2 on TiN) is a fundamental means for the successful implementation of this embodiment of the invention. Next, the photosensitive polymer layer is removed in order to open up the space between the pixels. The remaining part of the TiO2 layer thus forms the insulating layer 223.

[0093] In another embodiment, another insulating material, such as aluminum oxide, silicon oxide or silicon nitride, deposited in a conformal manner by ALD or CVD may advantageously be used for the insulating layer 223. Instead of wet etching of this layer, dry etching techniques may be used, in particular reactive dry etching (RIE).

[0094] Next, organic layers are deposited to form the OLED diode and the cathode. In this way, the structure shown is obtained, in which the pixels are separated by trenches, and the walls of the trenches are insulated by an insulating layer 223. The trenches may optionally extend in the substrate 210, in particular if their manufacture involves an etching step.

[0095] Insulating layer 223 may be a dielectric thin layer formed of another material such as Al2O3, SiO2, Si3N4, etc. deposited by ALD, PECVD, etc., other than TiO2. The thickness of this layer is typically about 5 nm to 25 nm, patterned by photolithography.

[0096] The optional top electrode can be produced in the form of a very fine layer of silver or aluminum with a thickness between 4 nm and 10 nm. If no top electrode is present, the common electrode 207 fulfills the function of an electrode for each elementary emission zone. In this case, between two adjacent partitions and delimited by two adjacent partitions, there advantageously extends a layer 206 for injecting charge carriers made of a material capable of injecting charge carriers into the OLED stack; molybdenum oxide or tungsten oxide can be used as the material. The thickness of this layer is typically between 0.5 nm and 5 nm.

[0097] The invention applies indifferently whether the basic emission areas are pixels or sub-pixels, and whether they emit white light or colored light; if the OLED layers of the sub-pixels all emit white light, the presence of the color filter 109 is necessary to allow the sub-pixels to be displayed in color.

[0098] It should be noted that, for the sake of simplicity, Figure 4 and Figure 5 The packaging system of the device is not shown. As is known from documents US 8,693,396 or US 9,082,999, the packaging system may comprise a three-layer aluminum oxide / polymer / aluminum oxide composite. The smoothing layer 108 may be deposited on top of the last three-layer system layer. In a variant, the invention makes it possible to simplify the packaging system by using a common conformal electrode 107 as the first three-layer composite layer. This variant is Figure 7 ( Figure 4 Variations of the devices in Figure 8 ( Figure 5) in which reference numerals 220, 221 and 222 respectively denote an encapsulation system, a polymer layer and an oxide layer, which oxide layer can in particular be silicon dioxide or aluminum oxide. The smoothing layer 108 is then located on top of the last encapsulation layer, which in this case is the oxide layer 222. It should be noted that the common conformal electrode 107 acts as a barrier to the ambient atmosphere and protects the layers below. The common conformal electrode itself can represent the encapsulation system (knowing that the smoothing layer and the optional color filter act as mechanical protection), even if this is not a preferred embodiment.

[0099] We now describe a third embodiment of the invention with reference to FIG6 , which has the structure of a tandem OLED device. FIG6( a) shows such a device 130, characterized by the superposition of two OLED stacks 131, 133 separated by a charge generation layer 132. The device follows the first embodiment described above for the structure of the filling element with insulating surface 103 and the partition with insulating surface 104. In this figure, there are no smoothing layers and no color filters, and optionally, no encapsulation layers, depending on the color emitted by the elementary light-emitting areas forming the pixels.

[0100] Figure 6(b) shows the stack of layers forming the OLED stack in more detail. The first OLED stack 131 and the second OLED stack 133 each include an electron injection and transport layer 1311, 1331 for injecting electrons into the electroluminescent layers 1312, 1332, and a hole injection and transport layer 1313, 1333 for injecting holes into the electroluminescent layers 1312, 1332. The electron injection and transport layer 1311 of the first OLED stack 131 and the hole injection and transport layer 1333 of the second OLED stack 133 are separated by the charge generation layer 132. In a variant (not shown in the figure), the order of the layers can be reversed, so that the electron injection and transport layers can be located below the corresponding electroluminescent layers and the hole injection and transport layers can be located above the corresponding electroluminescent layers.

[0101] In an advantageous variant shown in FIG. 6( c ), the electroluminescent layers 1312 , 1332 (shown only in FIG. 6( b )) are structured, i.e. the electroluminescent layers 1312 , 1332 are deposited only on the basic emission areas, excluding the areas occupied by filling elements with insulating surfaces and also excluding partitions. Such a structured deposition can be obtained by means of a template; this is a technique known per se. In this variant, only the hole injection and transport layers 1313 , 1333 and / or the electron injection and transport layers 1311 , 1331 are deposited on the entire surface of the display, including on the areas occupied by filling elements with insulating surfaces and partitions. In this area, the stack 141 , 143 schematically shown in FIG. 6( d ) is obtained: this is not an “OLED stack”, since it does not include an electroluminescent layer and therefore does not emit light. However, in the absence of partition elements with insulating surfaces, stray currents will pass through these injection and transport layers, which will contribute to the crosstalk phenomena that the invention aims to eliminate. In principle, the hole injection and transport layers 1313, 1333 and the electron injection and transport layers 1311, 1331 could also be deposited using template technology, but this would increase the processing time, would risk reducing industrial efficiency and would therefore incur unacceptable additional costs.

[0102] Example

[0103] The present invention is described below by way of examples, but these examples do not limit the scope of the present invention. These examples relate to embodiments and materials generally used to make the corresponding structures of various embodiments.

[0104] According to the arrangement of the "RGBW quad" type as shown in FIG2 (c), an OLED microdisplay with a 1280×1024 pixel matrix was prepared, each pixel having four subpixels. The size of the pixel is 9.4 μm×9.4 μm, and the size of the subpixel is 4.7 μm×4.7 μm. White pixels colored by color filters are used. The total size of the display screen of the microdisplay is 12.03 mm×9.63 mm.

[0105] The circuit of the pixel matrix comprising 2560×2048 sub-pixels is deposited on a silicon substrate 110 with a diameter of 200 mm using an active matrix (CMOS technology). The electrode layer 102 of the pixel is made of aluminum and has a size of 3.7μm×3.7μm. A silicon oxide layer is deposited and structured by photolithography to produce a gap fill. (A photoresist varnish or a cross-linkable polymer can also be deposited and then structured). Organic spacers are then deposited on the gap fill (by depositing and structuring a negative photoresist or another type of cross-linkable varnish). Alternatively, the spacers can be made by depositing and structuring an inorganic material (such as Al2O3 or SiO2) using anisotropic etching.

[0106] The stack of OLED layers (white light) is deposited on this assembly by thermal evaporation through a mask (in order to limit the deposition on the surface of each pixel) as follows:

[0107] - Instead of a standard cathode, semi-transparent metal type, a molybdenum oxide electron injection layer 106 with a thickness of 0.3-5 nm is deposited by thermal evaporation.

[0108] - On top of the MoO3 layer, a TCO layer (for example AZO, ZnO or SnO2) is deposited by ALD; this deposition covers the electrical connections of the cathode mentioned above. The thickness is between 25nm and 300nm.

[0109] A thin layer of encapsulation can be added on the TCO layer, but the TCO layer can also fulfill the function of an encapsulation layer alone. Color filters and an optional glass cover or other means for protecting the microdisplay screen are deposited on this assembly (preferably on a smoothing layer deposited on top of the encapsulation system). Next, the silicon wafer is cut to release the microdisplays, which can be integrated in more complex electronic devices.

[0110] Summary of the Objects of the Invention

[0111] According to a first object, the present invention relates to an electroluminescent display device 100, 200, comprising a plurality of pixels 120, 213 deposited on a substrate 110, 210, each pixel being formed by one or more basic emission regions 121a, 121b, 121c; 201a, 201b, 201c, each basic emission region comprising a base electrode 102a, 102b, 102c; 202a, 202b, 202c deposited on the substrate 110, 210, and an O LED stack 105, 205, said OLED stack comprising an electroluminescent layer deposited on said base electrodes 102a, 102b, 102c; 202a, 202b, 202c by a directional non-conformal deposition technique such as thermal evaporation, and said device 100 comprising a common electrode 107, 207 deposited on top of said OLED stack by a conformal deposition technique such as ALD (atomic layer deposition) or CVD (chemical vapor deposition), said device being characterized in that:

[0112] - two adjacent base electrodes 102a, 102b; 202a, 202b belonging to two adjacent elementary emitter regions 121a, 121b; 201a, 201b are separated by a filling element 103, 203 having an insulating surface, which fills a region 111, 211 between the adjacent base electrodes 102a, 102b; 202a, 202b and electrically insulates the adjacent base electrodes from each other;

[0113] - at least the surface of the filling element 103, 203 having an insulating surface in contact with the base electrodes 102a, 102b; 202a, 202b is made of an insulating material;

[0114] a spacer 104, 204 located above said filling element 103, 203 and separating the electroluminescent layers of the OLED stacks 105, 205 of two adjacent elementary emitting areas 121a, 121b; 201a, 201b;

[0115] - the layers of the OLED stack 105, 205 are interrupted by the separators 104, 204;

[0116] The common electrode 107 , 207 is continuous over the separator 104 , 204 .

[0117] Variant 1 of the first embodiment:

[0118] The device is characterized in that a conductive transparent layer 106 extends between two adjacent partitions 104 and is defined by two adjacent partitions 104, capable of injecting charge carriers into the OLED stack, and the conductive transparent layer 106 is deposited between the OLED stack 105 and the common electrode 107, and the thickness of the conductive transparent layer is preferably between 0.5nm and 5nm.

[0119] Variant 2 of the first embodiment:

[0120] The device, optionally according to variant 1 , is characterized in that said electrically conductive transparent layer 106 is deposited by a directional deposition technique such as thermal evaporation.

[0121] Variant 3 of the first embodiment:

[0122] The device (optionally according to any one of variants 1 or 2) is characterized in that the conductive transparent layer 106 is preferably molybdenum oxide or tungsten oxide.

[0123] Variant 4 of the first embodiment:

[0124] The device, optionally according to any one of variants 1 to 3, is characterized in that said filling element with insulating surface 103 and said spacer 104 constitute a barrier element extending upwards from substrate 110 .

[0125] Variant 5 of the first embodiment:

[0126] The device (optionally according to any of variants 1 to 4) is characterized in that any filling element having an insulating surface 103 is made of an insulating material.

[0127] Variant 6 of the first embodiment:

[0128] The device (optionally according to any one of variants 1 to 3) is characterized in that the separator 204 fills the top of the area between the adjacent base electrodes 202a, 202b.

[0129] Variant 7 of the first embodiment:

[0130] The device according to variant 6 is characterized in that the separator 204 includes the common electrode 207 .

[0131] Variant 9 of the first embodiment:

[0132] The device, optionally according to any one of variants 1 to 8, is characterized in that it comprises an encapsulation system 220 deposited on top of the common electrode 207 .

[0133] Variant 9 of the first embodiment:

[0134] The device according to variant 8 is characterized in that the encapsulation system 220 comprises a polymer layer 221 and an inorganic layer, preferably an oxide 222 .

[0135] Variant 10 of the first embodiment:

[0136] The device according to variant 9 is characterized in that it comprises an inorganic layer, preferably an oxide, deposited between the common electrode 207 and the polymer layer 221 .

[0137] Variant 11 of the first embodiment:

[0138] The device, optionally according to any one of variants 1 to 10, is characterized in that it comprises a smoothing layer 108, 208 deposited on top of said common electrode 107, 207 or on top of said packaging system 220.

[0139] Variant 12 of the first embodiment:

[0140] The device (optionally according to any one of variants 1 to 11) is characterized in that it comprises a system of color filters 109, 209, which are deposited on the common electrode 107, 207, or preferably deposited on the packaging system 220, or more preferably deposited on the smoothing layer 108, 208.

[0141] Variant 13 of the first embodiment:

[0142] The device (optionally according to any one of variants 1 to 12) is characterized in that it comprises two superimposed OLED stacks 131 , 133 .

[0143] Variant 14 of the first embodiment:

[0144] The device according to variant 13 is characterized in that the two OLED stacks 131 , 133 are separated by a charge generation layer 132 .

[0145] Variant 15 of the first embodiment:

[0146] A device (optionally according to any one of variants 1 to 14) is characterized in that the insulating material of the filling element 103, 203 protrudes over a portion of the surface of the base electrode 102a, 102b; 202a, 202b.

[0147] According to a second embodiment, the invention relates to an electroluminescent display device 200 comprising a plurality of pixels 213 deposited on a substrate 210, each pixel being formed by one or more elementary emission regions 201a, 201b, 201c, each elementary emission region comprising a base electrode 202a, 202b, 202c deposited on said substrate 210, and an OLED stack 205 comprising an electroluminescent layer, the electroluminescent layer being deposited on said base electrodes 202a, 202b, 202c by a directional non-conformal deposition technique such as thermal evaporation, and said device 200 comprising a common electrode 207, which is deposited on top of said OLED stack by a conformal deposition technique such as ALD (atomic layer deposition) or CVD (chemical vapor deposition), said device being characterized in that:

[0148] - two adjacent base electrodes 202a, 202b belonging to two adjacent elementary emitter regions 202a, 202b are separated by a filling element 203 having an insulating surface, which fills a region 211 between the adjacent base electrodes 202a, 202b and electrically insulates the adjacent base electrodes from each other;

[0149] - at least the surface of the filling element 203 having an insulating surface in contact with the base electrodes 202a, 202b is made of an insulating material;

[0150] a spacer 204 located above said filling element 203 and separating the electroluminescent layers of the OLED stack 205 of two adjacent elementary emitting areas 201a, 201b;

[0151] - the separator 204 fills the top of the area between the adjacent base electrodes 202a, 202b;

[0152] - The layers of the OLED stack 205 are discontinuous through the partition 204 (ie they are interrupted by the partition), whereas the common electrode 207 is continuous through the partition 204 (ie it is continuous over the partition).

[0153] Variant 1 of the second embodiment:

[0154] The device according to the second embodiment is characterized in that the partition 204 includes the common electrode 207 .

[0155] Variant 2 of the second embodiment:

[0156] The device, optionally according to variant 1 , is characterized in that it comprises an encapsulation system 220 deposited on top of the common electrode 207 .

[0157] Variant 3 of the second embodiment:

[0158] The device according to variant 2 is characterized in that the encapsulation system 220 comprises a polymer layer 221 and an inorganic layer, preferably an oxide 222 .

[0159] Variant 4 of the second embodiment:

[0160] The device according to variant 3 is characterized in that it comprises an inorganic layer, preferably an oxide, deposited between the common electrode 207 and the polymer layer 221 .

[0161] Variant 5 of the second embodiment:

[0162] The device, optionally according to any one of variants 1 to 4, is characterized in that it comprises a smoothing layer 108 , 208 deposited on top of said common electrode 107 , 207 or on top of said packaging system 220 .

[0163] Variant 6 of the second embodiment:

[0164] The device (optionally according to any one of variants 1 to 5) is characterized in that it comprises a system of color filters 209, which are deposited on the common electrode 207, or preferably on the packaging system 220, or even more preferably on the smoothing layer 208.

[0165] Variant 7 of the second embodiment:

[0166] The device (optionally according to any one of variants 1 to 6) is characterized in that it comprises two superimposed OLED stacks, which two OLED stacks may be separated by a charge generating layer.

[0167] Variant 8 of the second embodiment:

[0168] A device (optionally according to any one of variants 1 to 7) is characterized in that the insulating material of the filling element 203 protrudes over a portion of the surface of the base electrodes 202a, 202b.

[0169] Variant 9 of the second embodiment:

[0170] The device (optionally according to any one of variants 1 to 8) is characterized in that a conductive transparent layer extends between two adjacent partitions 204 and is bounded by the partitions 204, the conductive transparent layer being capable of injecting charge carriers into the OLED stack, the conductive transparent layer being deposited between the OLED stack 205 and the common electrode 207, the thickness of the conductive transparent layer preferably being between 0.5 nm and 5 nm.

[0171] Variant 10 of the second embodiment:

[0172] The device according to variant 9 is characterized in that the electrically conductive transparent layer is deposited by a directional deposition technique such as thermal evaporation.

[0173] Variant 11 of the second embodiment:

[0174] The device according to variant 9 or 10 is characterized in that the conductive transparent layer is preferably molybdenum oxide or tungsten oxide.

[0175] Variant 12 of the second embodiment:

[0176] The device (optionally according to any of variants 1 to 8) is characterized in that a top electrode extends between two adjacent partitions 204 and is bounded by the partitions 204, which top electrode is optional and can be made in the form of a very fine silver or aluminum layer with a thickness between 4nm and 10nm and deposited by a directional deposition technique such as thermal evaporation.

[0177] If no top electrode is present, the common electrode 207 fulfills the function of an electrode for each elementary emitting region.

[0178] Variant 13 of the second embodiment:

[0179] The device according to variant 12 is characterized in that the top electrode is made of a thin metal such as aluminum (Al), silver (Ag) or other; this layer can also be deposited by thermal evaporation, in which case it will only be deposited on horizontal surfaces.

Claims

1. An electroluminescent display device (200), comprising a plurality of pixels (213) deposited on a substrate (210), each pixel being formed by one or more basic emission regions (201a, 201b, 201c), two adjacent basic emission regions being separated by a space (211) having a vertical wall, each basic emission region comprising a base electrode (202a, 202b, 202c) deposited directly on the substrate (210), Furthermore, each elementary emission region further comprises an OLED stack (205), the OLED stack (205) comprising an electroluminescent layer deposited on the base electrodes (202a, 202b, 202c), and the device (200) comprises a common electrode (207) deposited on top of the OLED stack, characterized in that: The substrate (210) is an active matrix substrate including a CMOS type silicon substrate, or a substrate including a TFT transistor and made of glass or plastic material; Two adjacent base electrodes (202a, 202b) belonging to two adjacent elementary emission regions (201a, 201b) are separated by a filling element (203) having an insulating surface (223), the filling element (203) being arranged in the space (211) between the elementary emission regions (201), the insulating surface (223) covering the surface of the base electrode in the space (211) between the adjacent base electrodes (202a, 202b) and electrically insulating the adjacent base electrodes (202a, 202b) from each other; The space (211) between the adjacent base electrodes (202a, 202b) is in the form of a groove; At least the surface (223) of the filling element (203) having an insulating surface (223) which is in contact with the base electrodes (202a, 202b) is made of an insulating material.

2. The device according to claim 1, characterized in that a spacer (204) located on top of the filling element (203) and separating the electroluminescent layers of the OLED stack (205) of two adjacent elementary emission regions (201a, 201b); The separator (204) fills the top of the region between the adjacent base electrodes (202a, 202b); The partition (204) has a vertical wall and a transverse portion; The layers of the OLED stack (205) are interrupted by the vertical walls of the partition (204); The lateral portion of the spacer (204) comprises the OLED stack (205).

3. The device according to claim 1, characterized in that The insulating material (223) of the filling element (203) protrudes over a portion of the surface of the base electrode (202a, 202b).

4. The device according to claim 1, characterized in that The device comprises two superimposed OLED stacks separated by a charge generation layer.

5. The device according to claim 2, characterized in that The conductive transparent layer defined by the two adjacent partitions extends between the two adjacent partitions.

6. The device according to claim 5, characterized in that The conductive transparent layer is made of a thin metal including aluminum (Al) or silver (Ag).

7. The device according to claim 5, characterized in that The conductive transparent layer has a thickness between 4 nm and 10 nm and is deposited by a directional deposition technique.

8. The device according to claim 2, characterized in that Between and bounded by two adjacent partitions (204) extends a conductive transparent layer capable of injecting charge carriers into the OLED stack, the conductive transparent layer being deposited between the OLED stack (205) and the common electrode (207).

9. The device according to claim 8, characterized in that The conductive transparent layer is molybdenum oxide or tungsten oxide, has a thickness between 0.5 nm and 5 nm, and is deposited by a directional deposition technique.

10. The device according to any one of claims 1 to 9, characterized in that The device comprises a packaging system (220) deposited on top of the common electrode (207).

11. The device according to claim 10, characterized in that The packaging system (220) comprises a polymer layer (221) and an inorganic layer.

12. The device according to any one of claims 1 to 9, characterized in that The device comprises a packaging system (220) deposited on top of the common electrode, the packaging system (220) comprising a polymer layer (221), and the device comprises an inorganic layer deposited between the common electrode (207) and the polymer layer (221).

13. The device according to claim 10, characterized in that The device comprises a smoothing layer (208) deposited on top of the common electrode (207) or on top of the packaging system (220).

14. The device according to claim 11, characterized in that The device comprises a smoothing layer (208) deposited on top of the common electrode (207) or on top of the packaging system (220).

15. The device according to claim 12, characterized in that The device comprises a smoothing layer (208) deposited on top of the common electrode (207) or on top of the packaging system (220).

16. The device according to claim 10, characterized in that The device comprises a color filter system (209) deposited on the common electrode (207).

17. The device according to claim 10, characterized in that The device includes a color filter system deposited on the packaging system (220).

18. The device according to claim 13, characterized in that The device includes a color filter system deposited on the smoothing layer (208).

19. The device according to any one of claims 1 to 9, characterized in that The common electrode (207) is deposited by a conformal deposition technique, including ALD (atomic layer deposition) or CVD (chemical vapor deposition).

20. The device according to claim 11, characterized in that The inorganic layer of the packaging system (220) is an oxide.

21. The device according to claim 12, characterized in that The inorganic layer deposited between the common electrode (207) and the polymer layer (221) is an oxide.

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