Electroluminescent display device

Abstract

An electroluminescent display device is disclosed. The electroluminescent display device may include: a substrate; a first bank layer located on the substrate and defining a light-emitting area; a first electrode located on the light-emitting area of ​​the substrate, an end of the first electrode being adjacent to an end of the first bank layer without overlapping the first bank layer; and a light-emitting layer located on the first electrode.

Description

[0001] This application is a divisional application of the invention patent application with the application date of December 13, 2017, application number 201711328139.9, and invention name “Electroluminescent display device and manufacturing method thereof”. Technical Field

[0002] Embodiments of the present invention relate to an electroluminescent display device, and more particularly, to an electroluminescent display device manufactured by a solution process. Background Art

[0003] The electroluminescent display device is provided in such a manner that a light emitting layer is formed between two electrodes. The light emitting layer emits light by an electric field between the two electrodes, thereby displaying an image on the electroluminescent display device.

[0004] The light emitting layer may be formed of an organic material that emits light when excitons are generated by combination of electrons and holes and fall from an excited state to a ground state, or may be formed of an inorganic material such as quantum dots.

[0005] Hereinafter, a related art electroluminescent display device will be described with reference to the accompanying drawings.

[0006] Figure 1 is a cross-sectional view illustrating an electroluminescent display device of the related art.

[0007] like Figure 1 As shown in , the related art electroluminescent display device may include a substrate 10 , an electrode 20 , a first bank layer 31 , a second bank layer 32 , and a light emitting layer 40 .

[0008] The electrode 20 is provided on the substrate 10 .

[0009] A first bank layer 31 covering the end of the electrode 20 is provided on the substrate 10 .

[0010] The second bank layer 32 is disposed on the first bank layer 31. Since the width of the second bank layer 32 is smaller than that of the first bank layer 31, a two-step bank structure can be realized by the first bank layer 31 and the second bank layer 32, so that the spreadability of the solution at both sides of the light-emitting layer 40 can be improved, and the light-emitting layer 40 can be prevented from overflowing from the second bank layer 32.

[0011] The light emitting layer 40 is disposed on the electrode 20. The light emitting layer 40 may be formed by a solution process using an inkjet apparatus.

[0012] However, the related art electroluminescent display device has the following disadvantages.

[0013] In the case of the related art, the first bank layer 31 must be patterned to realize the 2-step bank structure. In this case, the surface of the electrode 20 may be damaged by an etching solution or etching gas used to pattern the first bank layer 31.

[0014] For example, when the first bank layer 31 is patterned by a wet etching process, pinholes may be generated in the surface of the electrode 20 due to the etching solution. In addition, when the first bank layer 31 is patterned by a dry etching process, foreign substances such as fluorine (F) and / or sulfur (S) may be generated in the surface of the electrode 20 due to the etching gas.

[0015] When the light emitting layer 40 is formed on the electrode 20 whose surface is damaged by pinholes or foreign matter, contaminants may penetrate into the light emitting layer 40 through the pinholes of the electrode 20 or foreign matter may penetrate into the light emitting layer 40, thereby shortening the life of the electroluminescent display device. Summary of the invention

[0016] Accordingly, embodiments of the present invention are directed to providing an electroluminescent display device that substantially overcomes one or more problems due to limitations and disadvantages of the related art.

[0017] An aspect of an embodiment of the present invention is to provide an electroluminescent display device capable of extending life by preventing an electrode from being damaged, and a method of manufacturing the same.

[0018] Other advantages and features of the embodiments of the present invention will be partially listed in the following description, and some of these advantages and features will become obvious to ordinary technicians in the relevant field after studying the following content or can be understood through the practice of the embodiments of the present invention. These purposes and other advantages of the embodiments of the present invention can be achieved and obtained through the structures specifically pointed out in the specification and claims and the drawings.

[0019] In order to achieve these and other advantages and in accordance with the intent of an embodiment of the present invention, as embodied and generally described herein, an electroluminescent display device is provided, which may include: a substrate; a first embankment layer located on the substrate and used to define a light-emitting area; a first electrode located on the light-emitting area of ​​the substrate; and a light-emitting layer located on the first electrode, wherein an end of the first electrode faces an end of the first embankment layer.

[0020] In another aspect of the present invention, an electroluminescent display device is provided, which may include: a substrate; a first embankment layer located on the substrate and defining a light-emitting area; a first electrode located on the light-emitting area, an end of the first electrode being adjacent to an end of the first embankment layer without overlapping with the first embankment layer; and a light-emitting layer located on the first electrode.

[0021] In another aspect of the present invention, an electroluminescent display device is provided, which may include: a substrate; a second electrode located on the substrate, wherein some areas of the second electrode are damaged; a light-emitting layer located on the second electrode; and a first electrode arranged between the second electrode and the light-emitting layer, wherein the first electrode prevents the damaged area of ​​the second electrode from contacting the light-emitting layer.

[0022] In another aspect of the present invention, an electroluminescent display device is provided, which may include: a substrate; a second electrode located on the substrate, the second electrode including a first transparent conductive layer located in an upper portion of the second electrode; a first embankment layer located on the second electrode and partially covering the second electrode, the first embankment layer defining a light-emitting area; a first electrode located on the second electrode and within the light-emitting area, the first electrode having a thickness greater than that of the first transparent conductive layer of the second electrode; and a light-emitting layer located on the first electrode.

[0023] In another aspect of the embodiments of the present invention, a method for manufacturing an electroluminescent display device is provided, which may include: forming a first embankment layer on a substrate; forming a photoresist pattern on the first embankment layer; forming a light-emitting area by removing a portion of the first embankment layer using the photoresist pattern as a mask; forming a first electrode on the photoresist pattern and the light-emitting area; removing the photoresist pattern and the first electrode formed on the photoresist pattern and leaving the first electrode formed on the light-emitting area; and forming a light-emitting layer on the first electrode remaining on the light-emitting area.

[0024] It is to be understood that both the foregoing general description and the following detailed description of the embodiments of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which provide a further understanding of the embodiments of the present invention and are incorporated in this application and constitute a part of this application, illustrate the embodiments of the present invention and together with the description are used to explain the principles of the embodiments of the present invention. In the drawings:

[0026] Figure 1 is a cross-sectional view illustrating an electroluminescent display device of the related art;

[0027] Figure 2 is a cross-sectional view illustrating an electroluminescent display device according to one embodiment of the present invention;

[0028] Figure 3 is a cross-sectional view illustrating an electroluminescent display device according to another embodiment of the present invention;

[0029] Figures 4A to 4G is a cross-sectional view illustrating a method for manufacturing an electroluminescent display device according to an embodiment of the present invention; and

[0030] Figures 5A to 5G is a cross-sectional view illustrating a method of manufacturing an electroluminescent display device according to another embodiment of the present invention. DETAILED DESCRIPTION

[0031] The advantages and features of the present invention and the methods for implementing the same will be explained by the following embodiments described with reference to the accompanying drawings. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments listed here. Rather, these embodiments are provided to make the present disclosure comprehensive and complete and to fully convey the scope of the present invention to those skilled in the art. In addition, the present invention is limited only by the scope of the claims.

[0032] The shapes, sizes, proportions, angles and quantities disclosed in the accompanying drawings for the purpose of describing the embodiments of the present invention are merely examples, and the present invention is not limited to the details shown in the drawings. Similar reference numerals refer to similar elements throughout the text. In the following description, when it is determined that a detailed description of related known functions or structures would unnecessarily obscure the key points of the present invention, the detailed description will be omitted. Where "including", "having" and "comprising" are used in the present application for description, other parts may be added unless "only" is used.

[0033] When interpreting an element, even if it is not explicitly stated, the element should be interpreted as including a range of error.

[0034] In describing a positional relationship, for example, when a positional order is described as “on,” “over,” “below,” and “after,” a case where there is no contact may be included unless “just” or “directly” is used.

[0035] When describing a time relationship, for example, when a time sequence is described as "after," "subsequently," "next," and "before," discontinuous cases may be included unless "directly" or "directly" is used.

[0036] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are merely used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present invention.

[0037] Those skilled in the art will fully appreciate that the features of the various embodiments of the present invention may be combined or combined with each other in part or in whole, and may interoperate and drive each other in various ways in technology. The embodiments of the present invention may be implemented independently of each other, or implemented together in a mutually dependent relationship.

[0038] Hereinafter, an electroluminescent display device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0039] Figure 2 is a cross-sectional view illustrating an electroluminescent display device according to an embodiment of the present invention. The electroluminescent display device may be an organic light emitting device (OLED). Figure 2 Only one sub-pixel is shown.

[0040] like Figure 2 As shown in , the electroluminescent display device according to one embodiment of the present invention may include a substrate 100 , a circuit device layer 200 , a first electrode 310 , a first bank layer 410 , a second bank layer 420 , and a light emitting layer 500 .

[0041] The substrate 100 may be formed of glass or transparent plastic, but is not limited to these materials.

[0042] The circuit device layer 200 is formed on the substrate 100 .

[0043] The circuit device layer 200 may include a light shielding layer 210 , a buffer layer 220 , an active layer 230 , a gate insulating film 240 , a gate electrode 250 , an interlayer insulating layer 260 , a source electrode 270 a , a drain electrode 270 b , and a planarization layer 280 .

[0044] The light shielding layer 210 is formed on the substrate 100 to prevent light from propagating to the active layer 230. Thus, the light shielding layer 210 overlaps the active layer 230, and the area of ​​the light shielding layer 210 is greater than that of the active layer 230.

[0045] The buffer layer 220 is formed on the light shielding layer 210, thereby insulating the light shielding layer 210 and the active layer 230 from each other. In addition, the buffer layer 220 prevents a material contained in the substrate 100 from diffusing to an upper portion.

[0046] The active layer 230 is formed on the buffer layer 220. The active layer 230 may be formed of a silicon-based semiconductor material or an oxide-based semiconductor material, but is not limited to these materials.

[0047] The gate insulating film 240 is formed on the active layer 230 , thereby insulating the active layer 230 and the gate electrode 250 from each other.

[0048] The gate electrode 250 is formed on the gate insulating film 240 .

[0049] An interlayer insulating layer 260 is formed on the gate electrode 250 , thereby insulating the gate electrode 250 from the source electrode 270 a / drain electrode 270 b .

[0050] The source electrode 270a and the drain electrode 270b are disposed on the interlayer insulating layer 260 and disposed at a predetermined interval from each other. The source electrode 270a and the drain electrode 270b are connected to one end and the other end of the active layer 230 via contact holes provided in the interlayer insulating layer 260, respectively.

[0051] The planarization layer 280 is formed on the source electrode 270 a and the drain electrode 270 b , thereby planarizing the surface of the substrate 100 .

[0052] The circuit device layer 200 may include a thin film transistor having a gate electrode 250 , an active layer 230 , a source electrode 270 a , and a drain electrode 270 b . Figure 2 A thin film transistor having a top gate structure in which the gate electrode 250 is disposed above the active layer 230 is shown, but is not limited to this structure. The circuit device layer 200 may include a thin film transistor having a bottom gate structure in which the gate electrode 250 is disposed below the active layer 230 .

[0053] The circuit device layer 200 may include a switching thin film transistor, a driving thin film transistor, a sensing thin film transistor, and a capacitor. As an example, Figure 2 The thin film transistor shown in corresponds to a driving thin film transistor.

[0054] The thin film transistor and the capacitor included in the circuit device layer 200 may be formed under the light emitting layer 500, or may be formed under the first bank layer 410 and the second bank layer 420. For example, in the case of a top emission type electroluminescent display device according to an embodiment of the present invention, even if the thin film transistor and the capacitor are disposed under the light emitting layer 500, the thin film transistor and the capacitor do not affect light emission, and thus the thin film transistor and the capacitor may be disposed under the light emitting layer 500. In the case of a bottom emission type electroluminescent display device according to an embodiment of the present invention, when the thin film transistor and the capacitor are disposed under the light emitting layer 500, the thin film transistor and the capacitor affect light emission, and thus the thin film transistor and the capacitor may be disposed under the first bank layer 410 and the second bank layer 420.

[0055] The first electrode 310 is formed on the circuit device layer 200. In detail, the first electrode 310 is formed on the emission area EA defined by the first bank layer 410.

[0056] The first electrode 310 can be used as an anode of the electroluminescent display device. When the electroluminescent display device according to the present invention is a bottom emission type, the first electrode 310 is used as a transparent electrode. Meanwhile, when the electroluminescent display device according to the present invention is a top emission type, the first electrode 310 is used as a reflective electrode.

[0057] The first electrode 310 may be electrically connected to the source electrode 270a of the circuit device layer 200 via the contact hole CH provided in the planarization layer 280, but is not limited to this structure. If necessary, the first electrode 310 may be electrically connected to the drain electrode 270b of the circuit device layer 200 via the contact hole CH provided in the planarization layer 280.

[0058] The first electrode 310 may be formed after the process of patterning the first bank layer 410. Therefore, the surface of the first electrode 310 may be prevented from being damaged by an etching solution or etching gas used in the process of patterning the first bank layer 410, which will be more easily understood through the manufacturing process described herein.

[0059] The first electrode 310 formed after the process of patterning the first bank layer 410 may not overlap the first bank layer 410. Thus, the end portion 310a of the first electrode 310 is not covered by the first bank layer 410, and thus the entire upper surface 310b of the first electrode 310 does not overlap the first bank layer 410 and may contact the light emitting layer 500.

[0060] In addition, the end portion 310a of the first electrode 310 may face the end portion 410a of the first bank layer 410. In particular, according to an embodiment, the end portion 310a of the first electrode 310 may contact the end portion 410a of the first bank layer 410.

[0061] In addition, a height H1 at the upper surface 310 b of the first electrode 310 may be lower than a height H2 at the upper surface 410 b of the first bank layer 410 .

[0062] The first bank layer 410 is formed on the circuit device layer 200. The first bank layer 410 is patterned to define a light emitting area EA on the circuit device layer 200.

[0063] As described above, the first bank layer 410 does not overlap the first electrode 310. In addition, the thickness T1 of the first bank layer 410 is less than the thickness T2 of the second bank layer 420, and the width W1 of the first bank layer 410 is greater than the width W2 of the second bank layer 420, so that the end 410a of the first bank layer 410 contacts the light emitting layer 500.

[0064] The first bank layer 410 has the same hydrophilicity as the light emitting layer 500. The first bank layer 410 having hydrophilicity may be formed of an inorganic insulating material such as silicon oxide. Therefore, when a solution for the light emitting layer 500 is applied, the spreadability of the solution on the first bank layer 410 may be improved.

[0065] The second bank layer 420 is formed on the first bank layer 410 .

[0066] The width W2 of the second bank layer 420 is smaller than the width W1 of the first bank layer 410. That is, the second bank layer 420 defines a larger area than the first bank layer 410. The second bank layer 420 may be patterned by coating a mixture solution of an organic insulating material having hydrophilicity and a hydrophobic material such as fluorine (F) and performing a photolithography process. By light irradiated by the photolithography process, the hydrophobic material such as fluorine (F) may be transferred to the upper portion 420a of the second bank layer 420, whereby the upper portion 420a of the second bank layer 420 has hydrophobicity, while the remaining portion of the second bank layer 420 has hydrophilicity. That is, a portion of the second bank layer 420 in contact with the first bank layer 410 has hydrophilicity, while the upper portion 420a of the second bank layer 420 has hydrophobicity, but is not limited to this structure. For example, the second bank layer 420 having hydrophobicity in its entirety may be provided.

[0067] The spreadability of the solution of the light emitting layer 500 can be improved by the first bank layer 410 and the predetermined portion of the second bank layer 420 having hydrophilicity. In particular, since the thickness T1 of the first bank layer 410 is less than the thickness T2 of the second bank layer 420, a 2-stage structure having hydrophilicity can be implemented by the first bank layer 410 and the second bank layer 420, so that the spreadability of the solution of the light emitting layer 500 to the end of each sub-pixel can be improved, and the light emitting layer 500 can be prevented from curling upward at the end of the sub-pixel due to its greater thickness.

[0068] In addition, the upper portion 420 a of the second bank layer 420 having hydrophobicity prevents the solution of the light emitting layer 500 from spreading to adjacent sub-pixels, so that the light emitting layer 500 can be prevented from being mixed together in adjacent sub-pixels.

[0069] Therefore, the first bank layer 410 and the second bank layer 420 may be disposed along the boundary between adjacent sub-pixels. Therefore, the entire matrix structure may be formed by the first bank layer 410 and the second bank layer 420, and a defined emission area EA may be prepared in each sub-pixel by using the first bank layer 410 and the second bank layer 420.

[0070] The light emitting layer 500 is formed on the first electrode 310. The light emitting layer 500 is disposed in the light emitting area EA, but is not disposed on the upper portion 420a of the second bank layer 420 as described above.

[0071] The light emitting layer 500 may be configured to emit red light (R), green light (G), or blue light (B), but is not limited to these colors.

[0072] The light emitting layer 500 may be formed by a solution process using an inkjet apparatus.

[0073] The light emitting layer 500 formed by a solution process may include at least one organic layer among a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. If necessary, the light emitting layer 500 may be formed of an inorganic material such as quantum dots.

[0074] For example, the light emitting layer 500 may be formed in a sequentially deposited structure of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

[0075] If necessary, the light emitting layer 500 may be formed in a sequentially deposited structure of a hole injection layer, a hole transport layer, and a light emitting layer. In this case, an electron transport layer and an electron injection layer may be additionally deposited on the light emitting layer 500 by a deposition process such as evaporation. Although not shown, the electron transport layer and the electron injection layer provided by the deposition process are not independently patterned according to each sub-pixel, and the electron transport layer and the electron injection layer are provided not only on the light emitting layer 500 but also on the second bank layer 420.

[0076] Although not shown, a cathode may be additionally provided on the light emitting layer 500 and the second bank layer 420. When the electroluminescent display device according to the present invention is a top emission type, the cathode serves as a transparent electrode. Meanwhile, when the electroluminescent display device according to the present invention is a bottom emission type, the cathode serves as a reflective electrode.

[0077] According to one embodiment of the present invention, the first electrode 310 is formed after the process of patterning the first bank layer 410, so that the surface of the first electrode 310 can be prevented from being damaged by the etching solution or etching gas used in the process of patterning the first bank layer 410, and the life of the electroluminescent display device can be extended.

[0078] Figure 3 is a cross-sectional view illustrating an electroluminescent display device according to another embodiment of the present invention. Figure 3 Only one sub-pixel is shown.

[0079] like Figure 3 As shown in , an electroluminescent display device according to another embodiment of the present invention may include a substrate 100 , a circuit device layer 200 , a first electrode 330 , a second electrode 320 , a first bank layer 410 , a second bank layer 420 , and a light emitting layer 500 .

[0080] The substrate 100 and the circuit device layer 200 are structurally similar to Figure 2The present invention is the same as the aforementioned embodiment, and thus a detailed description of the substrate 100 and the circuit device layer 200 will be omitted.

[0081] The first electrode 330 and the second electrode 320 are formed on the circuit device layer 200. In detail, the second electrode 320 is formed on the circuit device layer 200, and the first electrode 330 is formed on the second electrode 320. That is, the second electrode 320 is formed below the lower surface of the first electrode 330.

[0082] The first electrode 330 and the second electrode 320 can be used as an anode of an electroluminescent display device. In particular, in one embodiment, the first electrode 330 is formed of a transparent electrode and the second electrode 320 is formed of a reflective electrode, thereby realizing a top emission type electroluminescent display device according to an embodiment of the present invention.

[0083] In detail, the first electrode 330 may be formed of indium tin oxide (ITO), but is not limited to this material. In addition, the second electrode 320 may include a first transparent conductive layer 321, a reflective layer 322, and a second transparent conductive layer 323. The first transparent conductive layer 321 and the second transparent conductive layer 323 may be formed of indium tin oxide (ITO), and the reflective layer 322 may be formed of a silver (Ag) alloy, but is not limited to these materials.

[0084] The first electrode 330 may be electrically connected to the source electrode 270 a or the drain electrode 270 b of the circuit device layer 200 via the second electrode 320 .

[0085] In the same manner as in the aforementioned embodiment, the end 330a of the first electrode 330 is not covered by the first bank layer 410, and the entire upper surface 330b of the first electrode 330 is not covered by the first bank layer 410 and may be in contact with the light emitting layer 500. In addition, the end 330a of the first electrode 330 faces the end 410a of the first bank layer 410. Specifically, the end 330a of the first electrode 330 may be in contact with the end 410a of the first bank layer 410. In addition, the height H3 at the upper surface 330b of the first electrode 330 may be lower than the height H4 at the upper surface 410b of the first bank layer 410.

[0086] Unlike the first electrode 330, the second electrode 320 partially extends below the first bank 410. Therefore, an end 320a of the second electrode 320 overlaps the first bank 410. In addition, a width W3 of the second electrode 320 is greater than a width W4 of the first electrode 330.

[0087] The second electrode 320 may be electrically connected to the source electrode 270a of the circuit device layer 200 via the contact hole CH provided in the planarization layer 280, but is not limited to this structure. For example, the second electrode 320 may be electrically connected to the drain electrode 270b of the circuit device layer 200 via the contact hole CH provided in the planarization layer 280.

[0088] The second electrode 320 may be formed before the process of patterning the first bank layer 410. Therefore, the surface of the second electrode 320 may be damaged by an etching solution or an etching gas used in the process of patterning the first bank layer 410.

[0089] In detail, due to the etching solution, pin holes may be generated in the surface of the second transparent conductive layer 323 of the second electrode 320, or due to the etching gas, foreign substances such as fluorine (F) and / or sulfur (S) may be generated in the surface of the second transparent conductive layer 323 of the second electrode 320. In more detail, a predetermined portion of the second transparent conductive layer 323 having the pin holes or foreign substances corresponds to an area not covered by the first bank layer 410, i.e., the light emitting area EA, and pin holes or foreign substances are not generated in the remaining portion of the second transparent conductive layer 323 covered by the first bank layer 410, which will be more easily understood through the following manufacturing process.

[0090] Meanwhile, the first electrode 330 is formed on the surface of the second transparent conductive layer 323 provided with pinholes or foreign matter. Thus, contaminants remaining in the surface of the second transparent conductive layer 323 may be prevented from penetrating into the light emitting layer 500 by using the first electrode 330 .

[0091] Preferably, in order to prevent the penetration of pollutants, the thickness t3 of the second transparent conductive layer 323 is less than the thickness t4 of the first electrode 330. In order to obtain the microcavity effect of the electroluminescent display device, the thickness t4 of the first electrode 330 may be appropriately adjusted.

[0092] With Figure 2 In the same manner as the aforementioned embodiment of the present invention, the first bank layer 410 is patterned to define the light emitting area EA on the circuit device layer 200. In addition, the first bank layer 410 does not overlap with the first electrode 330, but overlaps with the second electrode 320. In addition, the thickness of the first bank layer 410 is smaller than the thickness of the second bank layer 420, and the width of the first bank layer 410 is larger than the width of the second bank layer 420. In addition, the first bank layer 410 has the same property as the light emitting layer 500, that is, hydrophilicity.

[0093] The second bank layer 420 is patterned on the first bank layer 410. Here, the material and structure of the second bank layer 420 are similar to those of the first bank layer 410. Figure 2 The present invention is the same as the aforementioned embodiment, and thus a detailed description of the second bank layer 420 will be omitted.

[0094] The light emitting layer 500 is formed on the light emitting area EA of the first electrode 330. Here, the material and structure of the light emitting layer 500 are similar to those of Figure 2 The light emitting layer 500 is the same as the aforementioned embodiment, and thus a detailed description of the light emitting layer 500 will be omitted.

[0095] Although not shown, a cathode may be additionally formed on the light emitting layer 500 and the second bank layer 420 .

[0096] according to Figure 3 In the embodiment of the present invention, the first electrode 330 is formed between the second electrode 320 and the light emitting layer 500. Therefore, even if the surface of the second electrode 320 is damaged by the etching solution or etching gas used in the process of patterning the first bank layer 410, the damaged surface of the second electrode 320 can be prevented from contacting the light emitting layer 500 by using the first electrode 330, thereby preventing contaminants remaining in the damaged surface of the second electrode 320 from penetrating into the light emitting layer 500.

[0097] Figures 4A to 4G is a cross-sectional view illustrating an exemplary method for manufacturing an electroluminescent display device according to an embodiment of the present invention, which involves Figure 2 The same reference numerals will be used throughout the drawings to refer to the same or like parts as much as possible, and detailed descriptions of the same parts will be omitted.

[0098] First, if Figure 4A As shown in FIG. 1 , a circuit device layer 200 is formed on a substrate 100 .

[0099] The circuit device layer 200 can be formed by various methods generally known to technicians in the relevant field, and can be obtained by a process of forming a light shielding layer 210, a buffer layer 220, an active layer 230, a gate insulating film 240, a gate electrode 250, an interlayer insulating layer 260, a source electrode 270a, a drain electrode 270b and a planarization layer 280 on a substrate 100.

[0100] As described above, the detailed structure of the circuit device layer 200 may be changed in various ways, and the process for forming the circuit device layer 200 may be changed in various methods generally known to those skilled in the art.

[0101] Then, if Figure 4B As shown in FIG. 1 , a first bank layer 410 is formed on the circuit device layer 200 , and a photoresist pattern 600 is formed on the first bank layer 410 .

[0102] The first bank layer 410 is formed on the entire surface of the substrate 100 .

[0103] Then, if Figure 4CAs shown in FIG. 6 , the emission area EA is prepared / defined by removing some portions of the first bank layer 410 using the photoresist pattern 600 as a mask. The pattern of the first bank layer 410 is completed by the remaining portions of the first bank layer 410 remaining without being removed by the etching process.

[0104] When etching some portions of the first bank layer 410, an etching solution or etching gas may penetrate into a space below the end portion 600a of the photoresist pattern 600, which may cause an undercut phenomenon. Therefore, the end portion 410a of the first bank layer 410 remaining after the etching process and the end portion 600a of the photoresist pattern 600 may not be located on the same vertical line.

[0105] Then, if Figure 4D As shown in FIG. 4 , the first electrode 310 is formed on the emission area EA prepared by removing some portions of the first bank layer 410. Some portions of the first electrode 310 are formed on the photoresist pattern 600, and the remaining portions of the first electrode 310 are formed on the circuit device layer 200.

[0106] By forming a contact hole CH in the planarization layer 280 , the first electrode 310 is connected to the source electrode 270 a or the drain electrode 270 b via the contact hole CH.

[0107] In this case, the end 310a of the first electrode 310 is not covered by the first bank layer 410. The end 310a of the first electrode 310 may face the end 410a of the first bank layer 410, and more specifically, the end 310a of the first electrode 310 may contact the end 410a of the first bank layer 410. In addition, the height at the upper surface 310b of the first electrode 310 may be lower than the height at the upper surface 410b of the first bank layer 410.

[0108] Then, if Figure 4E As shown in FIG. 6 , the photoresist pattern 600 is removed, and a portion of the first electrode 310 disposed on the photoresist pattern 600 is also removed, whereby the first electrode 310 remains in the emission area EA.

[0109] for Figure 4D For the aforementioned process, the height of the upper surface 310b of the first electrode 310 is lower than the height of the upper surface 410b of the first bank layer 410, so that the etching solution penetrates into the space below the end 600a of the photoresist pattern 600, thereby removing the corresponding portions of the photoresist pattern 600 and the first electrode 310.

[0110] Then, if Figure 4F As shown in FIG. 4 , the second bank layer 420 is formed on the first bank layer 410 .

[0111] As described above, the width of the second bank layer 420 is smaller than that of the first bank layer 410. The second bank layer 420 may be patterned by coating a mixture solution of an organic insulating material having hydrophilicity and a hydrophobic material such as fluorine (F) and performing a photolithography process. By light irradiated by the photolithography process, the hydrophobic material such as fluorine (F) may be transferred to the upper portion 420a of the second bank layer 420, whereby the upper portion 420a of the second bank layer 420 has hydrophobicity, while the rest of the second bank layer 420 has hydrophilicity.

[0112] Then, if Figure 4G As shown in FIG. 1 , the light emitting layer 500 is formed on the first electrode 310 . The light emitting layer 500 is formed by a solution process using an inkjet device. The light emitting layer 500 is not disposed on the upper portion 420 a of the second bank layer 420 .

[0113] Meanwhile, although not shown, a cathode may be additionally formed on the light emitting layer 500 and the second bank layer 420 .

[0114] According to one embodiment of the present invention, the first electrode 310 is formed after the process of patterning the first bank layer 410 , so that the surface of the first electrode 310 can be prevented from being damaged by an etching solution or etching gas used in the process of patterning the first bank layer 410 .

[0115] According to one embodiment of the present invention, the first electrode 310 is patterned by using the photoresist pattern 600 for patterning the first bank layer 410 , thereby eliminating the need for an additional mask for the first electrode 310 .

[0116] Figures 5A to 5G is a cross-sectional view illustrating an exemplary method for manufacturing an electroluminescent display device according to another embodiment of the present invention, which involves Figure 3 The same reference numerals will be used throughout the drawings to refer to the same or like parts as much as possible, and detailed descriptions of the same parts will be omitted.

[0117] First, if Figure 5A As shown in , a circuit device layer 200 is formed on a substrate 100 , and a second electrode 320 is formed on the circuit device layer 200 .

[0118] The circuit device layer 200 can be formed by various methods generally known to technicians in the relevant field, and can be obtained by a process of forming a light shielding layer 210, a buffer layer 220, an active layer 230, a gate insulating film 240, a gate electrode 250, an interlayer insulating layer 260, a source electrode 270a, a drain electrode 270b and a planarization layer 280 on a substrate 100.

[0119] As described above, the detailed structure of the circuit device layer 200 may be changed in various ways, and the process for forming the circuit device layer 200 may be changed in various methods generally known to those skilled in the art.

[0120] By forming a contact hole CH in the planarization layer 280 , the second electrode 320 is connected to the source electrode 270 a or the drain electrode 270 b via the contact hole CH.

[0121] The second electrode 320 may include a first transparent conductive layer 321 , a reflective layer 322 , and a second transparent conductive layer 323 which are sequentially disposed on the planarization layer 280 .

[0122] Then, if Figure 5B As shown in FIG. 1 , a first bank layer 410 is formed on the circuit device layer 200 and the second electrode 320 , and a photoresist pattern 600 is formed on the first bank layer 410 .

[0123] The first bank layer 410 is formed on the entire surface of the substrate 100 .

[0124] Then, if Figure 5C As shown in FIG. 1 , the light emitting area EA is prepared / defined by removing some portions of the first bank layer 410 using the photoresist pattern 600 as a mask. The pattern of the first bank layer 410 is completed by the remaining portions of the first bank layer 410 that are retained and not removed by the etching process. The end portion 320 a of the second electrode 320 is covered by the retained first bank layer 410.

[0125] In addition, the second electrode 320 is exposed in the light emitting area EA. In this case, the exposed surface of the second electrode 320 may be damaged by an etching solution or an etching gas used in a process of removing some portions of the first bank layer 410.

[0126] For example, when some portions of the first bank layer 410 are removed by a wet etching process, pinholes may be generated in the surface of the second electrode 320 due to the etching solution. In addition, when the first bank layer 410 is patterned by a dry etching process, foreign substances such as fluorine (F) and / or sulfur (S) may be generated in the surface of the second electrode 320 due to the etching gas.

[0127] In the present application, damage on some portion or surface of the second electrode 320 means pinholes or foreign matter on some portion or surface of the second electrode 320 .

[0128] Meanwhile, when etching some portions of the first bank layer 410, an etching solution or etching gas may penetrate into a space below the end portion 600a of the photoresist pattern 600, which may cause an undercut phenomenon. Therefore, the end portion 410a of the first bank layer 410 remaining after the etching process and the end portion 600a of the photoresist pattern 600 may not be located on the same vertical line.

[0129] Then, if Figure 5D As shown in FIG. 1 , the first electrode 330 is formed on the photoresist pattern 600 and the second electrode 320 . Some portions of the first electrode 330 are formed on the photoresist pattern 600 , and the remaining portions of the first electrode 330 are formed on the emission area EA of the second electrode 320 .

[0130] In this case, the end 330a of the first electrode 330 disposed on the second electrode 320 is not covered by the first bank layer 410. The end 330a of the first electrode 330 may face the end 410a of the first bank layer 410, and more specifically, in one example, the end 330a of the first electrode 330 may contact the end 410a of the first bank layer 410. In addition, the height at the upper surface 330b of the first electrode 330 disposed on the second electrode 320 may be lower than the height at the upper surface 410b of the first bank layer 410.

[0131] Then, if Figure 5E As shown in , the photoresist pattern 600 is removed, and the first electrode 330 disposed on the photoresist pattern 600 is also removed, whereby the first electrode 330 remains on the emission area EA of the second electrode 320 .

[0132] Then, if Fig. 5F As shown in FIG. 4 , the second bank layer 420 is formed on the first bank layer 410 .

[0133] The process of forming the second bank layer 420 is the same as that of the previous embodiment, and thus a detailed description of the process of forming the second bank layer 420 will be omitted.

[0134] Then, if Figure 5G As shown in FIG. 5 , a light emitting layer 500 is formed on the first electrode 330. The process of forming the light emitting layer 500 is the same as that of the previous embodiment, and thus a detailed description of the process of forming the light emitting layer 500 will be omitted.

[0135] Meanwhile, although not shown, a cathode may be additionally formed on the light emitting layer 500 and the second bank layer 420 .

[0136] According to one embodiment of the present invention, the first electrode 330 is formed after the process of patterning the first bank layer 410 , so that the surface of the first electrode 330 can be prevented from being damaged by an etching solution or etching gas used in the process of patterning the first bank layer 410 .

[0137] According to one embodiment of the present invention, the first electrode 330 is patterned by using the photoresist pattern 600 for patterning the first bank layer 410 , thereby eliminating the need for an additional mask for the first electrode 330 .

[0138] Without departing from the spirit or scope of the present invention, various modifications and changes can be made in the present invention, which will be apparent to those skilled in the art. Therefore, the present invention is intended to cover modifications and changes to the present invention that fall within the scope of the appended claims and their equivalents.

[0139] The above-mentioned embodiments can be combined to provide further embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent publications mentioned in this application and / or listed in the application data sheet are incorporated herein by reference in their entirety. If necessary, various aspects of the embodiments can be modified to provide further embodiments using the concepts of each patent, application, and publication.

[0140] These and other changes can be made to the embodiments in light of the above detailed description. Generally, in the following claims, the terms used should not be interpreted as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted as including all possible embodiments and the full range of equivalents covered by these claims. Therefore, the scope of the present invention is limited only by the claims.

[0141] CROSS-REFERENCE TO RELATED APPLICATIONS

[0142] This application claims the benefit of Korean Patent Application No. 10-2016-0181418, filed on Dec. 28, 2016, which is hereby incorporated by reference as if fully set forth herein.

Claims

1. An electroluminescent display device, comprising: substrate; a circuit device layer, wherein the circuit device layer is formed on the substrate; a second electrode located on the circuit device layer, the second electrode comprising a first transparent conductive layer located in an upper portion of the second electrode; a first bank layer located on the second electrode and partially covering the second electrode, the first bank layer defining a light emitting area; a first electrode located on the second electrode, the first electrode having a thickness greater than a thickness of the first transparent conductive layer of the second electrode; a light-emitting layer located on the first electrode; as well as a second bank layer located on the first bank layer, The second bank layer includes a material different from that of the first bank layer.

2. The electroluminescent display device according to claim 1, wherein: The second electrode includes a pinhole.

3. The electroluminescent display device according to claim 1, wherein: The second electrode includes foreign matter other than a material of the second electrode.

4. The electroluminescent display device according to claim 3, wherein: The foreign matter includes at least one of fluorine and sulfur.

5. The electroluminescent display device according to claim 1, wherein: The second bank layer defines a region wider than a region defined by the first bank layer.

6. The electroluminescent display device according to claim 1, wherein: The first bank layer has the same hydrophilicity as the light-emitting layer.

7. The electroluminescent display device according to claim 1, wherein: A height at an upper surface of the first electrode is lower than a height at an upper surface of the first bank layer.

8. The electroluminescent display device according to claim 1, wherein: An end portion of the second electrode overlaps the first bank layer.

9. The electroluminescent display device according to claim 1, wherein: The second electrode includes the first transparent conductive layer, the second transparent conductive layer, and a reflective layer, and the reflective layer is interposed between the first transparent conductive layer and the second transparent conductive layer.

10. The electroluminescent display device according to claim 9, wherein: The second transparent conductive layer of the second electrode contacts a lower surface of the first electrode, and a thickness of the second transparent conductive layer of the second electrode is smaller than a thickness of the first electrode.

11. The electroluminescent display device according to claim 1, wherein: The first bank layer is formed of a hydrophilic material, and an upper portion of the second bank layer is formed of a hydrophobic material.

12. The electroluminescent display device according to claim 1, wherein: The width of the second electrode is greater than the width of the first electrode.

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