Electroluminescent display device

Abstract

An electroluminescent display device comprising: a substrate (100) which includes an active area (AA) where a plurality of pixels (P) is provided, wherein the plurality of pixels (P) includes a red pixel, a green pixel and a blue pixel; a circuit element layer (200) arranged on the substrate (100); a first electrode (310) arranged on the circuit element layer (200) in each of the red pixel, the green pixel and the blue pixel; an auxiliary electrode (320) which is arranged on the circuit element layer (200) and is spaced apart from the first electrode (310); a first light-emitting layer (510) arranged in each of the red pixel, the green pixel and the blue pixel on the first electrode (310), wherein the first light-emitting layer (510) comprises a hole injection layer (HIL), a hole transport layer (HTL) and a light-emitting material layer (EML) and wherein the light-emitting material layer (EML) in the blue pixel is a blue light-emitting material layer (EML(B)); a buffer layer (520) arranged on the first light-emitting layer (510) in the blue pixel, wherein the buffer layer (520) is an electron transport layer (ETL), wherein the buffer layer (520) is formed using an inkjet process, wherein the buffer layer (520) is arranged on the blue light-emitting material layer (EML(B)) and wherein the buffer layer (520) is not arranged on the auxiliary electrode (320); a second light-emitting layer (530), wherein the second light-emitting layer (530) is an electron injection layer (EIL); and a second electrode (600) which is arranged on the second light-emitting layer (530), wherein the second light-emitting layer (530) is arranged in the red pixel and the green pixel on the first light-emitting layer (510), in the blue pixel is arranged on the buffer layer (520) and is arranged on the auxiliary electrode (320).

Description

BACKGROUND Area of ​​the invention

[0001] The present disclosure relates to an electroluminescent indicator device and, in particular, an electroluminescent indicator device to prevent the performance, efficiency, and lifetime of a device from being reduced. Discussion of related technology

[0002] Electroluminescent display devices are devices where a light-emitting layer is provided between two electrodes, and light is emitted with an electric field between the two electrodes, thereby displaying an image.

[0003] The light-emitting layer can be made of an organic material or an inorganic material such as a quantum dot. Within the light-emitting layer, an exciton is generated by a combination of an electron and a hole, and when the exciton is shifted from an excited state to a ground state, light is emitted.

[0004] The following describes an electroluminescence indicator device of the related technology with reference to the drawing.

[0005] Fig. Figure 1 is a schematic cross-sectional view of an electroluminescence display device of the related technology.

[0006] As in Fig. As seen in Figure 1, the electroluminescence indicator device of the prior art comprises a substrate 10, a circuit element layer 20, a first electrode 30, an auxiliary electrode 35, a dam 40, a light-emitting layer 50 and a second electrode 60.

[0007] The circuit element layer 20 is provided on the substrate 10. The circuit element layer 20 contains various signal lines, a thin-film transistor (TFT), a capacitor, and a planarization layer.

[0008] The first electrode 30 is provided on the circuit element layer 20. The first electrode 30 is structured in each of a plurality of pixels and acts as the anode of the electroluminescent display device of the related technology.

[0009] The auxiliary electrode 35 is spaced apart from the first electrode 30 and is located on the circuit element layer 20. The auxiliary electrode 35 is electrically connected to the second electrode 60 and reduces the resistance of the second electrode 60.

[0010] Dam 40 is designed in a matrix structure to define an emission zone.

[0011] The light-emitting layer 50 is provided on the first electrode 30 and comprises a first light-emitting layer 51 and a second light-emitting layer 52. The first light-emitting layer 51 and the second light-emitting layer 52 work together to emit light when an electric field is applied across both layers. If the first light-emitting layer 51 is not present in a region, no light is emitted from that region.

[0012] The first light-emitting layer 51 is formed in the emission area defined by the dam 40 by an inkjet process. Layers applied by an inkjet process may have a thickness in the center that is less than the thickness at the edge. This can result in a curved top surface on an inkjet-deposited layer or feature. For example, an inkjet-deposited layer or feature applied to a flat surface within an area defined by a dam may have a lower height from the center of the area compared to the height at the dam. The first light-emitting layer 51 comprises a hole injection layer (HIL), a hole transport layer (HTL), and a light-emitting material layer (EML).

[0013] The second light-emitting layer 52 is deposited over the entire substrate 10 by a deposition process. The second light-emitting layer 52 comprises an electron transport layer (ETL) and an electron injection layer (EIL).

[0014] The second electrode 60 is provided on the second light-emitting layer 52. The second electrode 60 is provided as a common layer of a plurality of pixels and acts as the cathode of the electroluminescent display device of the related technology.

[0015] In the electroluminescence display device of the related technology, the ETL of the second light-emitting layer 52 is formed by a deposition process over the entire metal substrate 10 and is thus provided on both the auxiliary electrode 35 and the first electrode 30.

[0016] The ETL, which is provided between the auxiliary electrode 35 and the second electrode 60, can be made of a conductive material in order to electrically connect the auxiliary electrode 35 to the second electrode 60.

[0017] Furthermore, in the electroluminescence display device of the related technology, a problem arises at an interface between the EML and the ETL, since the ETL is formed by a deposition process on the EML, which is formed by an inkjet process, causing a reduction in the efficiency and lifetime of a device.

[0018] The following publications are cited as state of the art: KR 10 2016 0 082 880 A, US 2015 / 0 155 515 A1, US 2015 / 0 333 110 A1, US 2017 / 0 352 707 A1, US 2017 / 0 278 910 A1 and US 2016 / 0 111 655 A1. SUMMARY

[0019] Accordingly, the present disclosure is directed to provide an electroluminescence indicator device which substantially avoids one or more problems due to limitations and disadvantages of the related technology.

[0020] One aspect of the present disclosure is aimed at providing an electroluminescence indicator device to prevent the performance, efficiency and lifetime of a device from being reduced.

[0021] Further advantages and features of the disclosure are partly set forth in the following description and partly become obvious to the person skilled in the art upon examination of the following or can be learned from the practical application of the disclosure. The objectives and other advantages of the disclosure can be realized and achieved through the structure set forth in particular in the written description and the claims, as well as in the accompanying drawings. Furthermore, the invention is specified in the claims.

[0022] To achieve these and other advantages, and in accordance with the purpose of the disclosure as embodied and described in detail herein, electroluminescent display devices and methods for manufacturing them are provided as described in the independent claims. Further embodiments are described in the dependent claims. According to one aspect of the present disclosure, an electroluminescent display device is provided comprising a substrate including an active region wherein a plurality of pixels is provided, the plurality of pixels comprising a red pixel, a green pixel, and a blue pixel, a circuit element layer arranged on the substrate, a first electrode arranged on the circuit element layer in each of the red pixel, the green pixel, and the blue pixel, and an auxiliary electrode.which is arranged on the circuit element layer and spaced apart from the first electrode, a first light-emitting layer arranged in each of the red pixel, the green pixel and the blue pixel on the first electrode, wherein the first light-emitting layer comprises a hole injection layer, a hole transport layer and a light-emitting material layer and wherein the light-emitting material layer in the blue pixel is a blue light-emitting material layer, a buffer layer arranged on the first light-emitting layer in the blue pixel, wherein the buffer layer is an electron transport layer, wherein the buffer layer is formed using an inkjet process, wherein the buffer layer is arranged on the blue light-emitting material layer and wherein the buffer layer is not arranged on the auxiliary electrode, a second light-emitting layer,wherein the second light-emitting layer is an electron injection layer, and a second electrode is arranged on the second light-emitting layer, wherein the second light-emitting layer is arranged in the red pixel and the green pixel on the first light-emitting layer, in the blue pixel is arranged on the buffer layer and is arranged on the auxiliary electrode.

[0023] It is understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide a further explanation of the claimed disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are included to facilitate a further understanding of the disclosure and are incorporated into this application and form part thereof, illustrate embodiments of the disclosure and, together with the description, serve to explain the principle of the disclosure. The drawings include: Fig. Figure 1 is a schematic cross-sectional view of an electroluminescence display device of the related technology; Fig. Figure 2 is a schematic top view of an electroluminescence indicator device according to an embodiment of the present disclosure; Fig. Figure 3 is a schematic top view showing pixels in an active area and a blind area of ​​an electroluminescent display device according to an embodiment of the present disclosure; Fig. Figure 4 is a cross-sectional view of an electroluminescent display device according to an embodiment of the present disclosure and is a cross-sectional view extending along line II' of Fig. 3 is taken; Fig. Figure 5A is a schematic cross-sectional view representing an organic light-emitting device of an electroluminescent display device according to an embodiment of the present disclosure; Fig. Figure 5B is a schematic cross-sectional view representing an organic light-emitting device of an electroluminescent display device according to an embodiment of the present disclosure; Fig. Figure 6 is a graphic comparing a drive voltage of an electroluminescent display device of the related technology with a drive voltage of an electroluminescent display device according to an embodiment of the present disclosure; Fig. Figure 7 is a graph comparing the power efficiency of an electroluminescent display device of the related technology with the power efficiency of an electroluminescent display device according to an embodiment of the present disclosure; Fig. Figure 8 is a graph comparing the lifetime of an electroluminescent indicator device of the related technology with the lifetime of an electroluminescent indicator device according to an embodiment of the present disclosure; and Fig. Figure 9 is a graph comparing a normalized light intensity of an electroluminescent display device of the related technology with a normalized light intensity of an electroluminescent display device according to an embodiment of the present disclosure with respect to a wavelength. DETAILED DESCRIPTION OF THE REVELATION

[0025] Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals are used throughout the drawings to refer to the same or similar parts.

[0026] The terms described in the description are to be understood as follows.

[0027] As used here, the singular forms "ein," "eine," and "der / die / das" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The expressions "erster / erste / erstes" and "zweiter / zweite / zweites" are intended to distinguish one element from the other, and these elements should not be restricted by these expressions. It is further understood that the expressions "umfassen," "umfassend," "haben," "habend," "einfassend," and / or "einfassend," when used here, indicate the presence of the specified features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.The term "at least one" should be understood to encompass any and all combinations of one or more of the associated listed elements. For example, the meaning of "at least one of a first element, a second element, and a third element" means the combination of all elements proposed by two or more of the first element, the second element, and the third element, as well as the first element, the second element, or the third element alone. The term "on" should be interpreted to include a case where one element is formed on top of another element, and furthermore, a case where a third element is positioned between them.

[0028] Exemplary embodiments of an electroluminescent indicator device according to the present disclosure are described in detail below with reference to the accompanying drawings. When adding reference numerals for elements in each drawing, it should be noted that, wherever possible, identical reference numerals already used to designate identical elements in other drawings should be used for elements. In the following description, where a detailed description of the relevant known function or configuration has been determined, the detailed description is omitted to avoid unnecessarily obscuring the important point of the present disclosure.

[0029] Exemplary embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0030] Fig. Figure 2 is a schematic top view of an electroluminescence indicator device according to an embodiment of the present disclosure.

[0031] As in Fig. As shown in Figure 2, the electroluminescence indicator device according to an embodiment of the present disclosure can include an active area AA, a blind area DA and a contact spot area PA.

[0032] The active area AA can serve as a display area that shows an image. A multitude of pixels can be provided within the active area AA, and an emission area can be provided within each of these multiple pixels.

[0033] In detail, signal lines, such as a gate line, a data line, a power line, and a reference line, can be provided in each of the multitude of pixels provided in the active area AA. Each pixel provided in the active area AA can also contain a multitude of thin-film transistors (TFTs) for switching the transmission of the signals applied through the signal lines, and a light-emitting device, driven by the multitude of TFTs to emit light, can be provided in each pixel.

[0034] The blind area DA can be arranged in such a way that it surrounds the active area AA.

[0035] Specifically, the blind area DA can be located outside the top, bottom, left, and right sides of the active area AA. A plurality of image pixels can be provided within the blind area DA, and a dummy emission area can be provided within each of these plurality of dummy pixels. Since the blind area DA is not the display area that shows an image, the dummy pixels provided within the blind area DA can have a structure that differs from that of any pixel provided within the active area AA. For example, a signal line, a TFT, and / or a light-emitting device may not be provided or may be incompletely provided within each of the dummy pixels provided within the blind area DA, and therefore no light can be emitted from each dummy pixel provided within the dummy area DA.When light is emitted in the blind area DA, the image quality of the electroluminescent display device deteriorates due to stray light occurring in the blind area DA.

[0036] The blind area DA prevents a process error from occurring between a center and an outer section of the active area AA. This is described in detail below.

[0037] A variety of stacking processes and a variety of masking processes can be performed to create the multitude of pixels in the active area AA. Each of the stacking processes can be a process for forming an insulating layer, a metal layer, or an organic layer through a physical deposition process, a chemical deposition process, a coating process, or an inkjet process, and each of the masking processes can be a method for structuring the insulating layer, the metal layer, or the organic layer formed by the stacking processes to have a specific shape using a photolithography process, a process familiar to those well-versed in the technology.

[0038] If, as described above, numerous batch processes and mask processes are performed on the active area AA, a process error may occur between the center and an edge of the active area AA due to a process characteristic. For this reason, the blind area DA can be provided at the edge of the active area AA, and therefore, if an error occurs, it will occur in the blind area DA without appearing in the active area AA.

[0039] In particular, if a light-emitting layer of the light-emitting device is formed by an inkjet process, a difference in drying of the light-emitting layer may occur between the center and the edge of a substrate, and in this case, if the blind area DA is not provided, the light emission between the center and the edge of the active area AA is not uniform.

[0040] Therefore, the blind area DA can be provided outside the active area AA, and thus, in a case where the light-emitting layer of the light-emitting device is formed by the inkjet process, the drying of the light-emitting layer is not uniform between the active area AA and the blind area DA, but the drying of the light-emitting layer is completely uniform in the active area AA.

[0041] The contact spot area PA can be located outside the blind area DA.

[0042] A circuit driver, such as a gate driver or a data driver, can be located in the contact patch area PA. The circuit driver can be positioned outside at least the upper, lower, left, and right sides of the blind area DA. The circuit driver located in the contact patch area PA can be connected via the blind area DA to the circuit element located in the active area AA.

[0043] Fig. Figure 3 is a schematic top view showing pixels in an active area and a blind area of ​​an electroluminescent display device according to an embodiment of the present disclosure.

[0044] As in Fig. As seen in Figure 3, an active region AA can be provided on a substrate 100, and a blind region DA can be provided outside the active region AA. A contact spot region PA can be provided outside the blind region DA, and a plurality of contact spots can be arranged within the contact spot region PA. Fig. Figure 3 schematically shows an upper left area of ​​substrate 100

[0045] The active area AA can contain a multitude of pixels P. This multitude of pixels P can include, but is not limited to, a red pixel that emits red light, a green pixel that emits green light, and a blue pixel that emits blue light.

[0046] Within the plurality of pixels P, an emission region can be defined by a dam 400. The dam 400 can be arranged to surround an edge of each of the plurality of pixels P. In this case, a contact part CNT can be provided for electrically connecting a second electrode to an auxiliary electrode between adjacent pixels of the plurality of pixels P. The contact part CNT can be a region that exposes the auxiliary electrode through a hole provided in the dam 400.

[0047] The multitude of pixels P can be arranged in a matrix type, as in Fig. Figure 3 illustrates, but is not limited to these. In other embodiments, the plurality of pixels P can be arranged in various ways known to those skilled in the art.

[0048] Within the blind area DA, a multitude of blind pixels DP can be provided. Some of the multitude of blind pixels DP can be arranged in a column that differs from the column in which pixels P are arranged. Some of the multitude of blind pixels DP can also be arranged in a column that is the same as the column in which pixels P are arranged.

[0049] Fig. Figure 4 is a cross-sectional view of an electroluminescent display device according to an embodiment of the present disclosure and is a cross-sectional view along line II' of Fig. 3, and each of the Fig. 5A and Fig. Figure 5B is a schematic cross-sectional view representing an organic light-emitting device of the electroluminescent display device according to an embodiment of the present disclosure.

[0050] As in Fig. As seen in Figure 4, the electroluminescence indicator device according to an embodiment of the present disclosure can include an active area AA, a blind area DA and a contact spot area PA, which are provided on a substrate 100.

[0051] Substrate 100 can be made of glass, plastic, and / or the like, but is not limited to these materials. Substrate 100 can be made of a transparent material or it can be made of an opaque material.

[0052] A light-blocking layer 110 can be arranged on the substrate 100. The light-blocking layer 110 can also be placed between the substrate 100 and an active layer 210 and can block the transmission of light to the active layer 210, thereby preventing deterioration of the active layer 210. The light-blocking layer 110 can include a lower light-blocking layer 111 and an upper light-blocking layer 112.

[0053] The lower light barrier layer 111 can be placed between the substrate 100 and the upper light barrier layer 112 and can increase the adhesive force between the substrate 100 and the upper light barrier layer 112. The lower light barrier layer 111 can also protect the lower surface of the upper light barrier layer 112, thus preventing corrosion of the lower surface of the upper light barrier layer 112. Therefore, the oxidation rate of the lower light barrier layer 111 can be lower than that of the upper light barrier layer 112. That is, the lower light barrier layer 111 can be made of a material that has a higher corrosion resistance than a material of the upper light barrier layer 112.As described above, the lower light-blocking layer 111 can act as an adhesion-enhancing layer or an anti-corrosion layer and can be made of titanium (Ti) or an alloy (MoTi) of molybdenum (Mo) and Ti, but is not limited to this.

[0054] The upper light barrier layer 112 can be provided on top of the lower light barrier layer 111. The upper light barrier layer 112 can be made of copper (Cu) or aluminum (Al), which have low resistance, but is not limited to these materials. The upper light barrier layer 112 can be made of a material that has a relatively lower resistance than the lower light barrier layer 111. The upper light barrier layer 112 can be connected to a drain electrode 265, and the thickness of the upper light barrier layer 112 can be set to be greater than that of the lower light barrier layer 111 in order to reduce the resistance of the drain electrode 265.

[0055] A buffer layer 120 can be arranged on the substrate 100. The buffer layer 120 can be arranged on the substrate 100 and the light barrier layer 110 to protect a thin-film transistor (TFT) from water penetrating the substrate 100, which is susceptible to water ingress.

[0056] The electroluminescence indicator device according to an embodiment of the present disclosure can be implemented as a top-emission type in which emitted light moves to an upper section, and in this case, the substrate 100 material can also be an opaque material as well as a transparent material.

[0057] Furthermore, according to an embodiment of the present disclosure, the electroluminescence indicator device can be implemented as a bottom emission type in which emitted light moves to a lower part, and in this case the material of the substrate 100 can be a transparent material.

[0058] A circuit element layer 200, a first electrode 310, an auxiliary electrode 320, a dam 400, a light emission layer 500 and a second electrode 600 can be provided in the active area AA on the substrate 100.

[0059] The circuit element layer 200 can be provided on the substrate 100. The circuit element layer 200 can include the active layer 210, a gate insulation layer 220, a gate electrode 230, an auxiliary line 240, an intermediate insulation layer 250, a source electrode 260, the drain electrode 265, a connecting line 270, a passivation layer 280, and a planarization layer 290.

[0060] The active layer 210 can be provided on the substrate 100. The active layer 210 can be formed from a silicon-based semiconductor material, an oxide semiconductor material and / or the like, but is not limited to this.

[0061] The gate insulation layer 220 can be provided on the active layer 210 and can isolate the active layer 210 from the gate electrode 230.

[0062] The gate electrode 230 can be provided on the gate insulation layer 220. The gate electrode 230 can include a lower gate electrode 231 and an upper gate electrode 232.

[0063] The lower gate electrode 231 can be positioned between the gate insulation layer 220 and the upper gate electrode 232 and can enhance the adhesion between the gate insulation layer 220 and the upper gate electrode 232. The lower gate electrode 231 can also protect the lower surface of the upper gate electrode 232, thus preventing corrosion of the lower surface of the upper gate electrode 232. Therefore, the oxidation rate of the lower gate electrode 231 can be lower than that of the upper gate electrode 232. That is, the lower gate electrode 231 can be made of a material with higher corrosion resistance than the material of the upper gate electrode 232. As described above, the lower gate electrode 231 can act as an adhesion-enhancing layer or an anti-corrosion layer and can be made of titanium or an alloy (MoTi) of molybdenum, but is not limited to this.

[0064] The upper gate electrode 232 can be provided at the lower gate electrode 231. The upper gate electrode 232 can be made of Cu or Al, which have low resistance, but is not limited to these materials. The upper gate electrode 232 can be made of a material that has a relatively lower resistance than the lower gate electrode 231. The thickness of the upper gate electrode 232 can be set greater than that of the lower gate electrode 231 in order to reduce the resistance of the gate electrode 230.

[0065] The auxiliary line 240 can be located on the same layer as the gate electrode 230 and can be spaced apart from the gate electrode 230. The auxiliary line 240 can be formed simultaneously with the gate electrode 230 by the same process and can be made of the same material as the gate electrode 230. The auxiliary line 240 can comprise a lower auxiliary line 241 and an upper auxiliary line 242. The lower auxiliary line 241 and the upper auxiliary line 242 can be made of the same material as the lower gate electrode 231 and the upper gate electrode 232.

[0066] The auxiliary line 240 can be electrically connected to the auxiliary electrode 320, which is described below. Since the auxiliary line 240 is electrically connected to the auxiliary electrode 320, the resistance of both the auxiliary electrode 320 and the second electrode 600 can be reduced.

[0067] The intermediate insulating layer 250 can be provided on the gate electrode 230 and can insulate the gate electrode 230 from the source and drain electrodes 260 and 265.

[0068] The source electrode 260 and the drain electrode 265 can face each other and can be spaced apart on the intermediate insulating layer 250. The source electrode 260 can be connected to one end of the active layer 210 through a contact hole provided in the intermediate insulating layer 250, and the drain electrode 265 can be connected to the other end of the active layer 210 through another contact hole provided in the intermediate insulating layer 250. The source electrode 260 can include a lower source electrode 261, a middle source electrode 262, and an upper source electrode 263, and the drain electrode 265 can include a lower drain electrode 266, a middle drain electrode 267, and an upper drain electrode 268.

[0069] The lower source and drain electrodes 261 and 266 can be positioned between the intermediate insulating layer 150 and the middle source and drain electrodes 262 and 267, and can enhance the adhesive force between the intermediate insulating layer 150 and the middle source and drain electrodes 262 and 267. The lower source and drain electrodes 261 and 266 can also protect the lower surfaces of the middle source and drain electrodes 262 and 267, thus preventing corrosion of these lower surfaces.

[0070] Therefore, the oxidation rate of each of the lower source and drain electrodes 261 and 266 can be lower than that of each of the middle source and drain electrodes 262 and 267. That is, the lower source and drain electrodes 261 and 266 can be made of a material with greater corrosion resistance than any of the middle source and drain electrodes 262 and 267. As described above, each of the lower source and drain electrodes 261 and 266 can act as an adhesion-enhancing layer or a corrosion-protective layer and can be made of, but is not limited to, a Mo-Ti alloy (MoTi).

[0071] The middle source and drain electrodes 262 and 267 can be positioned between the lower source and drain electrodes 261 and 266 and the upper source and drain electrodes 263 and 268. The middle source and drain electrodes 262 and 267 can be made of copper with low resistance, but this is not limited to this. The middle source and drain electrodes 262 and 267 can be made of a material with a relatively lower resistance than the lower source and drain electrodes 261 and 266. The thickness of each of the middle source and drain electrodes 262 and 267 can be greater than that of each of the lower source and drain electrodes 261 and 266 in order to reduce the overall resistance of the source and drain electrodes 260 and 265.

[0072] The upper source and drain electrodes 263 and 268 can be positioned between the passivation layer 280 and the middle source and drain electrodes 262 and 267, and can enhance the adhesion between the passivation layer 280 and the middle source and drain electrodes 262 and 267. The upper source and drain electrodes 263 and 268 can also protect the upper surfaces of the middle source and drain electrodes 262 and 267, thus preventing corrosion of these surfaces.

[0073] Therefore, the oxidation rate of each of the upper source and drain electrodes 263 and 268 can be lower than that of each of the middle source and drain electrodes 262 and 267. That is, the upper source and drain electrodes 263 and 268 can be made of a material with greater corrosion resistance than any of the middle source and drain electrodes 262 and 267. As described above, each of the upper source and drain electrodes 263 and 268 can act as an adhesion-enhancing layer or a corrosion-protective layer and can be made of, but is not limited to, a transparent conductive material such as indium tin oxide (ITO).

[0074] The connecting line 270 can be arranged on the same layer as the source and drain electrodes 260 and 265, or it can be spaced apart from them. The connecting line 270 and the source and drain electrodes 260 and 265 can be formed simultaneously from the same material using the same process. The connecting line 270 can comprise a lower connecting line 271, a middle connecting line 272, and an upper connecting line 273.

[0075] The lower connecting lead 271 can be made of the same material as the lower source and drain electrodes 261 and 266, so that it has the same thickness as the lower source and drain electrodes 261 and 266, and the middle connecting lead 272 can be made of the same material to have the same thickness as the middle source and drain electrodes 262 and 267. The upper connecting lead 273 can also be made of the same material to have the same thickness as the upper source and drain electrodes 263 and 268. In this case, the connecting lead 270 and the source and drain electrodes 260 and 265 can be formed simultaneously by the same process.

[0076] The connecting line 270 can be electrically connected to the auxiliary electrode 320, which is described below. Since the connecting line 270 is electrically connected to the auxiliary electrode 320, the resistance of both the auxiliary electrode 320 and the second electrode 600 can be reduced.

[0077] The passivation layer 280 can be provided on the source electrode 260, the drain electrode 265 and the connecting line 270 and can protect the TFT.

[0078] The planarization layer 290 can be placed on top of the passivation layer 280 and can planarize a surface on the substrate 100.

[0079] As described above, the circuit element layer 200 can contain a TFT comprising the active layer 210, the gate electrode 230, the source electrode 260, and the drain electrode 265. Figure 4 shows a TFT with an upper gate structure, in which the gate electrode 230 is located on the active layer 230, but is not limited to this. In other embodiments, the circuit element layer 200 can have a TFT with a lower gate structure, in which the gate electrode 230 is located below the active layer 230.

[0080] In circuit element layer 200, a circuit element containing various signal lines, TFTs, and a capacitor can be provided in each of a multitude of pixels. The signal lines can include a gate line, a data line, a power line, and a reference line, and the TFTs can include a switching TFT, a driver TFT, and a sampling TFT. The TFT that is in Fig. 4 can correspond to the driver TFT.

[0081] The switching TFT can be turned on by a gate signal supplied through the gate line and can transmit a data voltage supplied through the data line to the driver TFT.

[0082] The driver TFT can be switched on by the data voltage transmitted by the switching TFT to generate a data stream from power supplied through the power line, and it can supply the data stream to the first electrode 310.

[0083] The sampling TFT can detect a threshold voltage deviation of the driver TFT, which causes a deterioration in image quality. The sampling TFT can supply current from the driver TFT to the reference line in response to a sampling control signal supplied via the gate line or a separate sampling line.

[0084] The capacitor can hold the data voltage supplied to the driver TFT during a frame and can be connected to a gate electrode and a source electrode of the driver TFT.

[0085] In a case where the electroluminescent display device is implemented as a top-emission type according to an embodiment of the present disclosure, the light emission by the TFT is not affected even if the TFT is arranged below the light-emitting layer 500, and thus the TFT can be arranged below the light-emission layer 500.

[0086] The first electrode 310 can be provided on the circuit element layer 200. The first electrode 310 can be structured in each of the plurality of pixels and serve as the anode of the electroluminescent display device.

[0087] If the electroluminescent indicator device according to an embodiment of the present disclosure is implemented as a top-emission type, the first electrode 310 may include a reflective material for reflecting light to an upper section emitted by the light-emitting layer 500. In this case, the first electrode 310 may have a stacked structure comprising a transparent conductive material and the reflective material. If, on the other hand, the electroluminescent indicator device according to an embodiment of the present disclosure is implemented as a bottom-emission type, the first electrode 310 may be formed from the transparent conductive material.

[0088] The first electrode 310 can be connected to the drain electrode 265 of the TFT via a contact hole provided in the planarization layer 290 and the passivation layer 280. Depending on the case, the first electrode 310 can also be connected to the source electrode 260 of the TFT via a contact hole provided in the planarization layer 290 and the passivation layer 280.

[0089] The auxiliary electrode 320 can be arranged on the same layer as the first electrode 310 and can be spaced apart from the first electrode 310. The auxiliary electrode 320 and the first electrode 310 can be formed simultaneously from the same material using the same process.

[0090] The auxiliary electrode 320 can be electrically connected to the second electrode 600. Since the auxiliary electrode 320 is electrically connected to the second electrode 600, the resistance of the second electrode 600 can be reduced.

[0091] The auxiliary electrode 320 can include a lower auxiliary electrode 321, a middle auxiliary electrode 322, and an upper auxiliary electrode 323. The first electrode 310 can include a lower first electrode 311, a middle first electrode 312, and an upper first electrode 313.

[0092] The lower first electrode 311 can be positioned between the planarization layer 290 and the middle first electrode 312 to enhance adhesion between them. Similarly, the lower auxiliary electrode 321 can be positioned between the planarization layer 290 and the middle auxiliary electrode 322 to enhance adhesion between these two electrodes. The lower first electrode 311 and the lower auxiliary electrode 321 can also protect the lower surface of the middle first electrode 312, thus preventing corrosion of both.

[0093] Therefore, the oxidation rate of the lower first electrode 311 and the lower auxiliary electrode 321 can be lower than that of the middle first electrode 312 and the middle auxiliary electrode 322, respectively. That is, the lower first electrode 311 and the lower auxiliary electrode 321 can be made of a material with greater corrosion resistance than either of the middle first electrode 312 and the middle auxiliary electrode 322. As described above, both the lower first electrode 311 and the lower auxiliary electrode 321 can act as an adhesion force-enhancing layer or a corrosion protection layer and can be made of, but are not limited to, an alloy (MoTi) of Mo and Ti.

[0094] The middle first electrode 312 can be positioned between the lower first electrode 311 and the upper first electrode 313, and the middle auxiliary electrode 322 can be positioned between the lower auxiliary electrode 321 and the upper auxiliary electrode 323. The middle first electrode 312 and the middle auxiliary electrode 322 can be made of copper, which has a low resistance, but this is not limited to this. The middle first electrode 312 and the middle auxiliary electrode 322 can be made of a material that has a relatively lower resistance than the lower first electrode 311 and the lower auxiliary electrode 321. The thickness of each of the middle first electrode 312 and the middle auxiliary electrode 322 can be greater than that of the lower first electrode 311 and the lower auxiliary electrode 321 in order to reduce the overall resistance of the first electrode 310 and the lower auxiliary electrode 320.

[0095] The upper first electrode 313 and the upper auxiliary electrode 323 can protect the upper surfaces of the middle first electrode 312 and the middle auxiliary electrode 322, thereby preventing the upper surfaces of the middle first electrode 312 and the middle auxiliary electrode 322 from corroding.

[0096] Therefore, the oxidation rate of each of the upper first electrode 313 and the upper auxiliary electrode 323 can be lower than that of each of the middle first electrode 312 and the middle auxiliary electrode 322. That is, the upper first electrode 313 and the upper auxiliary electrode 323 can be made of a material with greater corrosion resistance than either of the middle first electrode 312 and the middle auxiliary electrode 322. As described above, both the upper first electrode 313 and the upper auxiliary electrode 323 can act as an adhesion-strengthening layer or a corrosion-protection layer and can be made of a transparent conductive material such as ITO, but are not limited to this.

[0097] The dam 400 can be positioned between adjacent pixels of the plurality of pixels P. The dam 400 can be provided entirely within a matrix structure and can define an emission region within a single pixel P. The dam 400 can be provided on the planarization layer 290 to conceal both ends of each of the first electrode 310 and the auxiliary electrode 320. Therefore, a plurality of first electrodes 300 and auxiliary electrodes 320, each structured within the plurality of pixels, can be isolated from one another by the dam 400.

[0098] The light-emitting layer 500 can be provided on the first electrode 310. The light-emitting layer 500 can be provided to emit light of different colors for each of the plurality of pixels P. For example, the light-emitting layer 500 can be provided to emit red light, green light, and blue light, but is not limited to this. The light-emitting layer 500 can be provided to emit white light, and in this case, a color filter can further be provided in a light path emitted by the light-emitting layer 500 for each of the plurality of pixels P.

[0099] With reference to Fig. 5A and Fig. 5B, according to one embodiment of the present disclosure, the light-emitting layer 500 can comprise a first light-emitting layer 510, a buffer layer 520 and a second light-emitting layer 530.

[0100] The first light-emitting layer 510 can be provided on the first electrode 310. The first light-emitting layer 510 can be provided in an emission region defined by the dam 400. The first light-emitting layer 510 can contain a hole injection layer (HIL), a hole transport layer (HTL), and a light-emitting material layer (EML). In a red pixel, the EML can be a red EML R, which emits red light. In a green pixel, the EML can be a green EML G, which emits green light. In a blue pixel, the EML can be a blue EML B, which emits blue light. The first light-emitting layer 510 can be formed by an inkjet process. Specifically, the first light-emitting layer 510 in each of the plurality of pixels P can be patterned by the inkjet process using a maskless inkjet device.

[0101] The buffer layer 520 can be provided on the first light-emitting layer 510. The buffer layer 520 can be located within the emission range defined by the dam 400. The buffer layer 520 can be patterned in each of the plurality of pixels P by inkjet printing using the inkjet device without a mask. That is, the buffer layer 520 can be provided only on the first light-emitting layer 510, without being located between the auxiliary electrode 320 and the second electrode 600. The buffer layer 520 can be formed from or comprise an organic material, and thus there is no limitation regarding the improvement of the device's performance. For example, the buffer layer 520 can be formed from a conductive organic material. Accordingly, the buffer layer 520 can act as a functional layer with a desired function based on a characteristic of each pixel.

[0102] In particular with reference to Fig. In 5A, the buffer layer 520 can be located in a blue pixel and can therefore be located on the blue EML B. The buffer layer must not be located in a red or green pixel and therefore must not be located on the red EML R or the green EML G. The blue EML B may have a property where combined excitons, electrons, or holes move to adjacent transport layers due to a low T1 voltage level, and therefore the emission efficiency is reduced compared to the red EML R and the green EML G. The voltage level T1 represents the energy level or voltage level of the lowest excited triplet state.Therefore, the buffer layer 520 can be formed from a material having a T1 voltage level higher than that of the blue EML B and a highest occupied molecular orbital (HOMO) level lower than that of the blue EML B, and can be placed on top of the blue EML B to improve the performance of the blue EML B device. The buffer layer 520 can act as a barrier layer to prevent excitons, electrons, or holes from moving to an adjacent electron injection layer. The buffer layer 520 can be formed from a material having a T1 voltage level higher than that of the blue EML B, the green EML G, and the red EML B. Referring to... Fig. 5B, the buffer layer 520 can be located in a blue pixel, in a green pixel and in a red pixel, and can therefore be located on the blue EML B, the green EML G and the red EML B.

[0103] Buffer layer 520 can be formed from a material containing carbazole, or from a material containing fluorene or acridine. Buffer layer 520 can also be formed from, but is not limited to, one or more materials selected from the group consisting of an arylamine-based material, a starburst-based aromatic amine material, and a spiro-type material.

[0104] Furthermore, the buffer layer 520 can be formed from a polymer, an oligomer, or a monomer with a molecular weight of 800 or more, or it can be formed from a material containing an alkyl group. The polymer, the oligomer, the monomer, and the material containing the alkyl group may be materials that cannot be applied to a deposition process, and thus the buffer layer 520 can be formed by an inkjet process. As described above, the buffer layer 520 can be formed on the first light-emitting layer 510, which is formed by the inkjet process, using the inkjet process instead of the deposition process, thereby minimizing the interface problem between the first light-emitting layer 510 and the buffer layer 520.

[0105] Furthermore, the buffer layer 520 can be made of a material to reduce the roughness of its upper surface. Therefore, even if the second light-emitting layer 530 is formed on the buffer layer 520 by a deposition process, the interface problem is reduced. Also, the buffer layer 520 can be formed on the first light-emitting layer 510 by an inkjet process in a state where the second light-emitting layer 530 is not yet deposited on the first light-emitting layer 510. Then, the second light-emitting layer 530 can be formed on the buffer layer 520 by a deposition process, thus protecting the upper surface of the first light-emitting layer 510.

[0106] Furthermore, the buffer layer 520 can function as an electron transport layer (ETL).

[0107] The second light-emitting layer 530 can be provided on the buffer layer 520 and the auxiliary electrode 320. The second light-emitting layer 530 can be formed entirely on the substrate 100 by a deposition process, with the exception of the contact spot area PA. Therefore, the second light-emitting layer 530 can also be provided on an upper surface of the dam 400. Since the second light-emitting layer 530 is located between the auxiliary electrode 320 and the second electrode 600, it can be formed from a conductive material (for example, metal) to electrically connect the auxiliary electrode 320 to the second electrode 600. Accordingly, the auxiliary electrode 320 can be electrically connected to the second electrode 600 via the second light-emitting layer 530. The second light-emitting layer 530 can include an electron injection layer (EIL).

[0108] The second electrode 600 can be provided on the light-emitting layer 500. More specifically, the second electrode 600 can be provided on the second light-emitting layer 530. The second electrode 600 can serve as the cathode of the electroluminescent display device. The second electrode 600, like the light-emitting layer 500, can also be provided on the dam 400. Therefore, the second electrode 600 can function as a common electrode that applies a common voltage to the multitude of pixels.

[0109] An encapsulation layer can be provided on the second electrode 600 (not shown). The encapsulation layer can be arranged to cover the active area AA and, furthermore, to cover the blind area DA. The encapsulation layer can prevent oxygen or water from penetrating the TFT and the light-emitting layer 500. For this purpose, the encapsulation layer can comprise at least one inorganic layer and at least one organic layer.

[0110] A circuit element layer 200, a dam 400, a blind light-emitting layer 500 and a second electrode 600 can be provided in the blind area DA on the substrate 100.

[0111] The circuit element layer 200, which is provided in the blind area DA, can be formed by the same process as the circuit element layer 200, which is provided in the active area AA, in order to have the same structure.

[0112] However, the present embodiment is not limited to this. In other embodiments, some of the signal lines, such as a gate line, a data line, a power line, and a reference line, may not be provided in the circuit element layer 200, which is located in the blind area DA, or at least one of the switching TFTs and one of the driver TFTs may not be located in the circuit element layer 200. Therefore, no light can be emitted in the blind area DA. Depending on the case, the circuit element layer 200, which is located in the blind area DA, may be incompletely configured, so that one of the switching TFTs and one of the driver TFTs does not operate.

[0113] The dam 400 provided in the blind area DA can be located between adjacent blind pixels of a multitude of blind pixels DP. The dam 400 provided in the blind area DA can define a blind emission area in a single blind pixel DP. In the drawing, only one pixel DP is shown as being located in the blind area DA, but the multitude of blind pixels DP can be located in the blind area DA.

[0114] Similar to the Dam 400 provided in the active region AA, the Dam 400 provided in the blind region DA can be entirely implemented in a matrix structure and can define the blind emission region in a single blind pixel DP. As a result, the Dam 400 can be provided in the matrix structure in both the active region AA and the blind region DA.

[0115] The blind light-emitting layer 500, provided in the blind area DA, can be located on the circuit element layer 200. The blind light-emitting layer 500, provided in the blind area DA, can be made of the same material to have the same thickness as the light-emitting layer 500 provided in the active area AA.

[0116] Since the blind area DA is not a display area that shows an image, the blind pixels DP provided in the blind area DA can be configured to emit no light. However, if light is emitted in the blind area DA, the display quality of the electroluminescent display device deteriorates due to stray light occurring in the blind area DA.

[0117] To prevent light from being emitted by the blind pixels DP, no TFT may be provided in the circuit element layer 200 that is located in the blind area DA, or no first electrode may be provided in the blind area DA.

[0118] The second electrode 600, which is provided in the blind area DA, can be formed in a structure extending from the second electrode 600, which is provided in the active area AA. However, the second electrode 600 must not be provided in the blind area DA, and therefore no light can be emitted in the blind area DA.

[0119] The contact patch 700 can be provided in the contact patch area PA on the substrate 100. The contact patch 700 can include a signal contact patch 710 and a contact patch electrode 720.

[0120] The signal contact spot 710 can be provided on the insulating layer 225. The signal contact spot 710 can be provided on the same layer as the gate electrode 230, which is provided in the active region AA. The signal contact spot 710 can include a lower signal contact spot 711 and an upper signal contact spot 712.

[0121] The signal contact spot 711 can be formed from the same material to have the same thickness as the lower gate electrode 231, and the upper signal contact spot 712 can be formed from the same material to have the same thickness as the upper gate electrode. In this case, the signal contact spot 710 and the gate electrode 230 can be formed simultaneously by the same process.

[0122] The contact spot electrode 720 can be provided on the intermediate insulation layer 250. The contact spot electrode 720 can be provided on the same layer as the source and drain electrodes 260 and 265, which are provided in the active region AA. The contact spot electrode 720 can be connected to the signal contact spot 710 via a contact hole. The contact spot electrode 720 can be exposed externally and connected to an external driver. The contact spot electrode 720 can comprise a lower contact spot electrode 721, a middle contact spot electrode 722, and an upper contact spot electrode 723.

[0123] The lower contact spot electrode 721 can be formed from the same material to have the same thickness as the lower source and drain electrodes 261 and 266, the middle contact spot electrode 722 can be formed from the same material to have the same thickness as the middle source and drain electrodes 262 and 267, and the upper contact spot electrode 723 can be formed from the same material to have the same thickness as the upper source and drain electrodes 263 and 268. In this case, the contact spot electrode 720 and the source and drain electrodes 260 and 265 can be formed simultaneously by the same process.

[0124] As described above, in the electroluminescent display device according to the embodiments of the present disclosure, since the buffer layer 520 is formed on the first light-emitting layer 510 by the inkjet process, the buffer layer 520 can only be provided on the first light-emitting layer 510, and thus the buffer layer 520 can be formed from or comprise an organic material, thereby improving the performance of the blue pixel device.

[0125] Furthermore, in the electroluminescent display device according to the embodiments of the present disclosure, since the buffer layer 520 is formed by the inkjet process on the first light-emitting layer 510, a problem at the interface between the first light-emitting layer 510 formed by the inkjet process and the second light-emitting layer 530 formed by the deposition process is reduced, thereby preventing a reduction in the efficiency and lifetime of the organic light-emitting device.

[0126] Fig. Figures 6 to 9 are diagrams comparing an electroluminescence indicator device of related technology with an electroluminescence indicator device according to an embodiment of the present disclosure.

[0127] In the electroluminescent display device of the related technology, an organic light-emitting device comprises a first electrode, a first light-emitting layer, a second light-emitting layer, and a second electrode without a buffer layer. On the other hand, in the electroluminescent display device according to an embodiment of the present disclosure, as described above with reference to the Fig. 4 and Fig. As described in section 5, an organic light-emitting device comprises a first electrode, a first light-emitting layer, a buffer layer, a second light-emitting layer and a second electrode.

[0128] Fig. Figure 6 is a graphic comparing a drive voltage of the electroluminescent display device of the related technology with a drive voltage of the electroluminescent display device according to an embodiment of the present disclosure.

[0129] With reference to Fig. 6, in the electroluminescent display device of the related technology, when a current density of 0 mA / cm² 2 If the current density is up to 50 mA / cm², the drive voltage is in a range of approximately 3 V to 7 V. If the electroluminescent display device according to an embodiment of the present disclosure has a current density of 0 mA / cm², 2 up to 50 mA / cm 2 The drive voltage is in a range of approximately 3 V to 7.2 V. In comparison with the electroluminescent display device of the related prior art, the electroluminescent display device according to an embodiment of the present disclosure still includes the buffer layer 520, but there is hardly any difference between the drive voltages.

[0130] Fig. Figure 7 is a graph comparing a current efficiency of the electroluminescent display device of the related technology with a current efficiency of the electroluminescent display device according to an embodiment of the present disclosure.

[0131] Referring to Fig. 7, if the luminance of the panel is 0 cd / m² 2 up to 2,000 cd / m² 2 The current efficiency of the electroluminescence indicator device according to one embodiment of the present disclosure is far higher than the current efficiency of the electroluminescence indicator device of the related technology.

[0132] Fig. Figure 8 is a diagram comparing the lifetime of the electroluminescent indicator device of the related technology with the lifetime of the electroluminescent indicator device according to an embodiment of the present disclosure.

[0133] With reference to Fig. 8. In the prior art electroluminescent display device, the luminescence decreases over time from about 101% to about 83%. In the electroluminescent display device according to one embodiment of the present disclosure, the luminescence decreases from about 101% to about 86% even when the same amount of time elapses as in the electroluminescent display device of the related technology. As described above, the lifetime of the electroluminescent display device according to one embodiment of the present disclosure is longer than the lifetime of the electroluminescent display device of the related technology.

[0134] Fig. Figure 9 is a diagram comparing a normalized light intensity of an electroluminescent display device of the related technology with a normalized light intensity of an electroluminescent display device according to an embodiment of the present disclosure with respect to a wavelength.

[0135] With reference to Fig. 9, in comparison to the electroluminescent display device of the related technology, the electroluminescent display device according to one embodiment of the present disclosure further comprises the buffer layer 520, however, a normalized light intensity of the electroluminescent display device according to one embodiment of the present disclosure is almost similar to a normalized light intensity of the electroluminescent display device of the related technology with respect to a wavelength.

[0136] As described above, in the electroluminescent display device according to the embodiments of the present disclosure, since the buffer layer on the first light-emitting layer is formed by the inkjet process, the buffer layer can be provided only on the first light-emitting layer, and thus the buffer layer can be formed from or comprise an organic material, thereby improving the performance of the blue pixel device.

[0137] Furthermore, since in the electroluminescent display device according to the embodiments of the present disclosure the buffer layer on the first light-emitting layer is formed by the inkjet process, a problem at the interface between the first light-emitting layer formed by the inkjet process and the second light-emitting layer formed by the deposition process is reduced, thereby preventing a decrease in the efficiency and lifetime of the organic light-emitting device. The following list contains aspects of the disclosure and forms part of the description. These aspects can be combined in any compatible combination beyond that expressly mentioned. The aspects can also be combined with any compatible features described herein: Aspect 1. Electroluminescent display device, comprising: a substrate with an active area in which a plurality of pixels is provided, wherein the plurality of pixels includes a red pixel, a green pixel and a blue pixel; a circuit element layer that is arranged on the substrate; a first electrode, which is arranged on the circuit element layer, in each of the red pixel, the green pixel and the blue pixel; an auxiliary electrode that is arranged on the circuit element layer and is spaced apart from the first electrode; a first light-emitting layer arranged in each of the red pixel, the green pixel and the blue pixel on the first electrode, wherein the first light-emitting layer comprises a hole injection layer, a hole transport layer and a light-emitting material layer, and wherein the light-emitting material layer in the blue pixel is a blue light-emitting material layer; a buffer layer arranged on the first light-emitting layer, wherein the buffer layer is an electron transport layer, wherein the buffer layer is formed using an inkjet process, wherein the buffer layer is arranged on the blue light-emitting material layer, and wherein the buffer layer is not arranged on the auxiliary electrode; a second light-emitting layer, wherein the second light-emitting layer is an electron injection layer; and a second electrode arranged on the second light-emitting layer, wherein the second light-emitting layer is arranged in the red pixel and the green pixel on the first light-emitting layer, in the blue pixel is arranged on the buffer layer and is arranged on the auxiliary electrode. Aspect 2. Electroluminescent display device according to Aspect 1, wherein the buffer layer comprises a non-conductive material. Aspect 3. Electroluminescent display device according to Aspect 1 or 2, wherein the buffer layer has a T1 voltage level higher than a T1 voltage level of the blue light-emitting material layer and a highest occupied molecular orbital (HOMO) level lower than a HOMO level of the blue light-emitting material layer. The term “T1 voltage level” may refer to the energy level or the voltage level of the lowest excited triplet state in the respective layer. Aspect 4. Electroluminescent display device according to any one of Aspects 1 to 3, wherein the buffer layer comprises a polymer, an oligomer or a monomer having a molecular weight of 800 or more. Aspect 5. Electroluminescent display device according to one of aspects 1 to 4, wherein the buffer layer comprises a material containing an alkyl group. Aspect 6. Electroluminescent display device according to any one of Aspects 1 to 5, wherein the buffer layer comprises a material comprising carbazole or a material comprising fluorene or acridine. Aspect 7. Electroluminescent display device according to any one of Aspects 1 to 6, wherein the buffer layer comprises one or more materials selected from a group which includes an arylamine-based material, a starburst aromatic amine-based material and a spiro-type material. Aspect 8. Electroluminescent display device according to any of aspects 1 to 7, wherein the first light-emitting layer is formed by an inkjet process and the second light-emitting layer is formed by a deposition process. Aspect 9. Electroluminescent display device according to any one of aspects 1 to 8, wherein the second light-emitting layer comprises a conductive material and is electrically connected to the auxiliary electrode and the second electrode. Aspect 10. Electroluminescent display device according to one of aspects 1 to 9, wherein the substrate further comprises a blind area provided at the periphery of the active area. Aspect 11. Method for manufacturing the electroluminescent display device according to one of Aspects 1 to 10, wherein the buffer layer is formed by an inkjet process. Aspect 12. Method for manufacturing the electroluminescent display device according to one of claims 1 to 11, wherein the first light-emitting layer is formed by an inkjet process and the second light-emitting layer is formed by a deposition process.

Claims

[1] An electroluminescent display device comprising: a substrate (100) comprising an active region (AA) where a plurality of pixels (P) is provided, wherein the plurality of pixels (P) includes a red pixel, a green pixel and a blue pixel; a circuit element layer (200) arranged on the substrate (100); a first electrode (310) arranged on the circuit element layer (200) in each of the red pixel, the green pixel and the blue pixel; an auxiliary electrode (320) which is arranged on the circuit element layer (200) and is spaced apart from the first electrode (310); a first light-emitting layer (510) arranged in each of the red pixel, the green pixel and the blue pixel on the first electrode (310), wherein the first light-emitting layer (510) comprises a hole injection layer (HIL), a hole transport layer (HTL) and a light-emitting material layer (EML) and wherein the light-emitting material layer (EML) in the blue pixel is a blue light-emitting material layer (EML(B)); a buffer layer (520) arranged on the first light-emitting layer (510) in the blue pixel, wherein the buffer layer (520) is an electron transport layer (ETL), wherein the buffer layer (520) is formed using an inkjet process, wherein the buffer layer (520) is arranged on the blue light-emitting material layer (EML(B)) and wherein the buffer layer (520) is not arranged on the auxiliary electrode (320); a second light-emitting layer (530), wherein the second light-emitting layer (530) is an electron injection layer (EIL); and a second electrode (600) which is arranged on the second light-emitting layer (530), wherein the second light-emitting layer (530) is arranged in the red pixel and the green pixel on the first light-emitting layer (510), in the blue pixel is arranged on the buffer layer (520) and is arranged on the auxiliary electrode (320). [2] The electroluminescent display device according to claim 1, wherein the buffer layer (520) comprises an organic material. [3] The electroluminescent display device according to claim 1 or 2, wherein the buffer layer (520) has a T1 voltage level higher than a T1 voltage level of the blue light-emitting material layer and has a highest occupied molecular orbital level value lower than a highest occupied molecular orbital level value of the blue light-emitting material layer, wherein the term ‘T1 voltage level’ refers to the energy level or voltage level of the lowest excited triplet state in the respective layer. [4] The electroluminescent display device according to any one of claims 1 to 3, wherein the buffer layer (520) comprises a polymer, an oligomer or a monomer having a molecular weight of 800 or more. [5] The electroluminescent display device according to any one of claims 1 to 4, wherein the buffer layer (520) comprises a material containing an alkyl group. [6] The electroluminescence indicator device according to any one of claims 1 to 5, wherein the buffer layer (520) comprises a material containing carbazole or a material containing fluorene or acridine. [7] The electroluminescent display device according to any one of claims 1 to 6, wherein the buffer layer (520) comprises one or more materials selected from a group which includes an arylamine-based material, a starburst-based aromatic amine material and a spiro-type material. [8] The electroluminescent display device according to any one of claims 1 to 7, wherein the first light-emitting layer (510) is formed by an inkjet process and the second light-emitting layer (530) is formed by a deposition process. [9] The electroluminescent display device according to any one of claims 1 to 8, wherein the second light-emitting layer (530) comprises a conductive material and is electrically connected to the auxiliary electrode (320) and the second electrode (600). [10] The electroluminescence indicator device according to any one of claims 1 to 9, wherein the substrate (100) further comprises a blind area (DA) provided at the periphery of the active area (AA). [11] A method for manufacturing the electroluminescent display device according to any one of claims 1 to 10, wherein the buffer layer (520) is formed by an inkjet process. [12] A method for manufacturing the electroluminescent display device according to any one of claims 1 to 11, wherein the first light-emitting layer (510) is formed by an inkjet process and the second light-emitting layer (530) is formed by a deposition process.

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