electroluminescent display device

Abstract

To provide an electroluminescent display device which is fabricated by a solution process and furthermore enables prevention of flowing of a light emission stack of any one subpixel to another subpixel.SOLUTION: The present disclosure provides an electroluminescent display device including: a substrate including a first subpixel and a second subpixel which are arranged in a first direction; first electrodes which are provided in the first subpixel and the second subpixel, respectively; a bank which is provided in a boundary between the first subpixel and the second subpixel on the substrate; light emission stacks which are provided on the first electrode and the bank, respectively; and a second electrode which is provided in the light emission stack. The bank includes a first bank and a second bank provided in the first bank. The light emission stack is provided in a first layer provided in each of the first subpixel and the second subpixel, and on the first layer, and includes a second layer continuous to the second subpixel from the first subpixel. The first bank is provided on a lower side of the second layer, and the second bank is provided on the second layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electroluminescent display device, and more particularly to an electroluminescent display device that can be manufactured using a solution process. [Background technology]

[0002] An electroluminescent display device comprises a first electrode, a second electrode, and a light-emitting stack disposed between the first electrode and the second electrode, and displays an image by causing the light-emitting stack to emit light in response to an electric field between the two electrodes.

[0003] The light-emitting stack may include an organic material that emits light when excitons are annihilated by the recombination of electrons and holes. An exciton is an electrically neutral particle containing an electrostatically bound electron and hole. When the organic material absorbs light with an energy higher than its band gap, an exciton is generated, exciting an electron from the valence band to the conduction band. When a conduction band electron in the exciton recombines with a hole in the valence band, the exciton is annihilated and the energy of the exciton can be converted into light. Summary of the Invention [Problem to be solved by the invention]

[0004] The light-emitting stack can be formed by a vacuum deposition process, but in this case, expensive vacuum deposition equipment is required, which can increase manufacturing costs. In particular, in the case of large electroluminescent displays, the size of the mask and vacuum deposition equipment for pattern formation becomes even larger, which reduces productivity during mass production.

[0005] Therefore, in order to reduce the manufacturing cost, a method of forming the light emitting stack by a solution process using an inkjet device or the like has been proposed.

[0006] However, when the light-emitting stack is formed by a solution process, for example, a problem may occur in that the solution for forming the red light-emitting stack flows from the red sub-pixel to the adjacent green sub-pixel, degrading the image quality of the green sub-pixel.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide an electroluminescent display device that can prevent a light-emitting stack of one sub-pixel from flowing into another sub-pixel while using a solution process. [Means for solving the problem]

[0008] To achieve the above object, the present invention provides an electroluminescent display device comprising: a substrate including first sub-pixels and second sub-pixels arranged in a first direction; a first electrode provided in each of the first sub-pixels and the second sub-pixels on the substrate; a bank provided at a boundary between the first sub-pixels and the second sub-pixels on the substrate; a light-emitting stack provided on the first electrode and the bank; and a second electrode provided on the light-emitting stack, the bank comprising a first bank and a second bank provided on the first bank, the light-emitting stack comprising a first layer provided in each of the first sub-pixels and the second sub-pixels, and a second layer provided on the first layer and continuing from the first sub-pixel to the second sub-pixel, the first bank being provided below the second layer and the second bank being provided on the second layer.

[0009] The present invention also provides an electroluminescent display device comprising: a substrate including a plurality of first sub-pixels and a plurality of second sub-pixels; first banks provided at boundaries between the plurality of first sub-pixels and the plurality of second sub-pixels, at boundaries between the plurality of first sub-pixels, and at boundaries between the plurality of second sub-pixels; second banks provided in a continuous linear structure along the boundaries between the plurality of first sub-pixels and the plurality of second sub-pixels; and third banks provided in a discontinuous linear structure at boundaries between the plurality of first sub-pixels and at boundaries between the plurality of second sub-pixels. [Effects of the Invention]

[0010] According to the present invention as described above, the following effects are obtained.

[0011] According to one embodiment of the present invention, the first layer of the light-emitting stack, which needs to be separated into sub-pixels, is formed by a solution process such as an inkjet process, and the first bank separates the sub-pixels, thereby preventing adjacent sub-pixels from being continuous.

[0012] According to one embodiment of the present invention, the second and fourth layers of the light-emitting stack, which do not need to be separated for each sub-pixel, can be formed without a mask by a vacuum deposition method such as evaporation.

[0013] According to one embodiment of the present invention, by further forming a second bank on the second layer of the light-emitting stack, the third layer of the light-emitting stack, which needs to be separated into sub-pixels, is formed using a solution process such as an inkjet process, but is interrupted by the second bank and does not become continuous between adjacent sub-pixels.

[0014] According to another embodiment of the present invention, a third bank is formed at the boundary between one subpixel emitting light of the same hue and another adjacent subpixel, and by ensuring a predetermined space for ink movement, the fluidity of the light-emitting stack is improved, thereby preventing the problem of mottling occurring in a specific subpixel. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic plan view of an electroluminescent display device according to an embodiment of the present invention; [Figure 2] 2 is a schematic cross-sectional view of an electroluminescence display device according to an embodiment of the present invention, taken along line AB of FIG. 1; [Figure 3] 1 is a schematic cross-sectional view of a light emitting stack according to an embodiment of the present invention. [Figure 4] 1A and 1B are schematic cross-sectional views of an electroluminescent display device according to various embodiments of the present invention, illustrating a portion of a boundary region between a first sub-pixel and a second sub-pixel; [Figure 5] 1A and 1B are schematic cross-sectional views of an electroluminescent display device according to various embodiments of the present invention, illustrating a portion of a boundary region between a first sub-pixel and a second sub-pixel; [Figure 6] 1A and 1B are schematic cross-sectional views of an electroluminescent display device according to various embodiments of the present invention, illustrating a portion of a boundary region between a first sub-pixel and a second sub-pixel; [Figure 7] 2 is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, taken along line CD in FIG. 1; [Figure 8] 1 is a schematic plan view of an electroluminescent display device according to another embodiment of the present invention; [Figure 9] 9 is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, taken along line EF of FIG. 8; [Figure 10] 1 is a schematic plan view of an electroluminescent display device according to various embodiments of the present invention; [Figure 11] 1 is a schematic plan view of an electroluminescent display device according to various embodiments of the present invention; [Figure 12] 1 is a schematic plan view of an electroluminescent display device according to various embodiments of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0016] The advantages and features of the present invention, as well as methods for achieving them, will become more apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be embodied in various different forms. These embodiments are provided solely to complete the disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art. The present invention is defined solely by the claims.

[0017] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for illustrating embodiments of the present invention are merely examples, and the present invention is not limited to the details shown in the drawings. The same reference numerals refer to the same components throughout the specification. Furthermore, in describing the present invention, if a detailed description of related prior art is deemed to unnecessarily obscure the gist of the present invention, such a detailed description will be omitted. When terms such as "comprise," "have," and "consist of" are used in this specification, other parts may be added unless "only" is used. When a component is expressed in the singular, the plural is also included unless otherwise explicitly stated.

[0018] When interpreting elements, they are interpreted as including a margin of error even if there is no other explicit description.

[0019] When describing a positional relationship, for example, when the positional relationship of two parts is described using "above," "on top," "below," or "next to," one or more other parts may be located between the two parts, unless "immediately" or "directly" is used.

[0020] When describing a temporal relationship, for example, when the temporal sequence is described using "after," "following," "next to," or "before," it can include non-sequential situations, as long as "immediately" or "directly" is not used.

[0021] Although terms such as "first," "second," and the like are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a first component referred to below may be a second component within the technical concept of the present invention.

[0022] The features of the examples of this application may be partially or wholly combined or combined with each other, and may be technically interlocked and driven in various ways, and each example may be implemented independently of the others, or may be implemented together in association with each other.

[0023] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] FIG. 1 is a schematic plan view of an electroluminescent display device according to an embodiment of the present invention.

[0025] As can be seen from FIG. 1, an electroluminescent display device according to one embodiment of the present invention includes a substrate 100, a plurality of sub-pixels (SP1, SP2, SP3) formed on the substrate 100, a first electrode 300 formed in each of the plurality of sub-pixels (SP1, SP2, SP3), and banks 410, 420 formed in boundary regions between the plurality of sub-pixels (SP1, SP2, SP3).

[0026] The plurality of sub-pixels (SP1, SP2, SP3) may include a first sub-pixel (SP1), a second sub-pixel (SP2), and a third sub-pixel (SP3) arranged in a first direction, for example, the X-axis direction.

[0027] The first sub-pixel (SP1) may emit light of a first color, the second sub-pixel (SP2) may emit light of a second color, and the third sub-pixel (SP3) may emit light of a third color.

[0028] The plurality of first sub-pixels (SP1) can be arranged in a second direction intersecting the first direction, for example, the Y-axis direction, and similarly, the plurality of second sub-pixels (SP2) and the plurality of third sub-pixels (SP3) can also be arranged in the second direction.

[0029] The arrangement structure of the plurality of sub-pixels (SP1, SP2, SP3) can be changed to various forms known in the art.

[0030] The first electrode 300 may function as an anode of an electroluminescent display device, may be patterned in each of the plurality of sub-pixels (SP1, SP2, SP3), and may be surrounded by the banks 410 and 420.

[0031] The banks 410 and 420 are provided in boundary regions between the plurality of sub-pixels (SP1, SP2, SP3) and can individually define the sub-pixel (SP1, SP2, SP3) regions.

[0032] The banks 410 , 420 include a first bank 410 and a second bank 420 .

[0033] The first bank 410 may be formed in a mesh structure in boundary regions between the sub-pixels (SP1, SP2, SP3). Specifically, the first bank 410 may be formed in boundary regions between the first sub-pixel (SP1), the second sub-pixel (SP2), and the third sub-pixel (SP3) arranged in the first direction, and may also be formed in boundary regions between the first sub-pixels (SP1), the second sub-pixels (SP2), and the third sub-pixels (SP3) arranged in the second direction.

[0034] The second bank 420 may be formed in a different pattern from the first bank 410. In particular, the second bank 420 is formed in boundary regions between the first sub-pixels (SP1), second sub-pixels (SP2), and third sub-pixels (SP3) arranged in the first direction, but may not be formed in boundary regions between the first sub-pixels (SP1), second sub-pixels (SP2), and third sub-pixels (SP3) arranged in the second direction. Therefore, the second bank 420 may be formed in a stripe structure that extends long in the second direction and is spaced apart at predetermined intervals in the first direction.

[0035] Figure 2 is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, which corresponds to a cross-section taken along line AB in Figure 1. That is, Figure 2 is a cross-sectional view including boundary regions between a first sub-pixel SP1, a second sub-pixel SP2, and a third sub-pixel SP3 that emit light of different colors.

[0036] As can be seen from FIG. 2, an electroluminescent display device according to one embodiment of the present invention comprises a substrate 100, a circuit element layer 200, a first electrode 300, banks 410, 420, a light-emitting stack 500, a second electrode 600, an encapsulating layer 700, a color filter 800, a light-shielding layer 850, and a protective layer 900.

[0037] The substrate 100 may be made of glass or transparent plastic, but is not limited thereto, and may be made of a semiconductor material such as a silicon wafer. When the electroluminescent display device according to an embodiment of the present invention is a top emission type, not only a transparent material but also an opaque material may be used for the substrate 100. However, when the electroluminescent display device according to an embodiment of the present invention emits light in a bottom emission type, a transparent material is used for the substrate 100.

[0038] The circuit element layer 200 is formed on a substrate 100 .

[0039] The circuit element layer 200 includes a driving thin film transistor.

[0040] The driving thin film transistor includes an active layer 210 formed on the substrate 100, a gate insulating film 220 formed on the active layer 210, a gate electrode 230 formed on the gate insulating film 220, an interlayer insulating film 240 formed on the gate electrode 230, and a source electrode 251 and a drain electrode 252 formed on the interlayer insulating film 240 and connected to the active layer 210 through holes formed in the interlayer insulating film 240 and the gate insulating film 220. Although the drawing shows a driving thin film transistor having a top gate structure in which the gate electrode 230 is formed on the active layer 210, the present invention may also include a driving thin film transistor having a bottom gate structure in which the gate electrode 230 is formed below the active layer 210.

[0041] The circuit element layer 200 may further include a passivation layer 260 and a planarization layer 270 disposed on the driving thin film transistor. The passivation layer 260 is disposed on the source electrode 251 and the drain electrode 252, and the planarization layer 270 is disposed on the passivation layer 260.

[0042] The passivation layer 260 and the planarization layer 270 may include contact holes through which the first electrode 300 may be connected to the drain electrode 252. In some cases, the first electrode 300 may be connected to the source electrode 251 through the contact holes.

[0043] Meanwhile, the circuit element layer 200 may further include, in addition to the driving thin film transistor, various signal lines including gate lines, data lines, power lines and reference lines, various thin film transistors including switching thin film transistors and sensing thin film transistors, and capacitors.

[0044] The switching thin film transistor is switched by a gate signal supplied to the gate line, and serves to supply a data voltage supplied from the data line to the driving thin film transistor.

[0045] The driving thin film transistor is switched by the data voltage supplied from the switching thin film transistor, generates a data current from the power source supplied through the power line, and supplies the data current to the first electrode 300 .

[0046] The sensing thin film transistor serves to sense the threshold voltage deviation of the driving thin film transistor, which may cause degradation of image quality, and supplies the current of the driving thin film transistor to the reference line in response to a sensing control signal supplied from the gate line or a separate sensing line.

[0047] The capacitor serves to maintain the data voltage supplied to the driving thin film transistor for one frame, and is connected to the gate terminal and the source terminal of the driving thin film transistor, respectively.

[0048] Each of the switching thin film transistor, the driving thin film transistor, and the sensing thin film transistor may be modified to have various structures known in the art, such as a bottom gate structure or a top gate structure.

[0049] The circuit element layer 200 may further include a passivation layer for protecting the switching thin film transistor, the driving thin film transistor, and the sensing thin film transistor, and a planarization layer formed on the passivation layer.

[0050] The first electrode 300 is formed for each sub-pixel (SP1, SP2, SP3) on the circuit element layer 200. The first electrode 300 may function as an anode of the electroluminescent display device. The first electrode 300 may include a transparent electrode when the electroluminescent display device according to the present invention is a bottom emission type, or may include a reflective electrode when the electroluminescent display device according to the present invention is a top emission type.

[0051] The banks 410 and 420 are provided on the circuit element layer 200 and include a first bank 410 and a second bank 420 .

[0052] The first bank 410 is formed on the circuit element layer 200 to cover both ends of the first electrode 300, and is formed at the boundaries between the plurality of sub-pixels (SP1, SP2, SP3).

[0053] The first bank 410 may be formed in a two-layer structure of a lower bank layer 410a and an upper bank layer 410b.

[0054] The lower bank layer 410a may be formed to contact the first electrode 300 and the circuit element layer 200. The lower bank layer 410a may be formed to a thickness thinner than the upper bank layer 410b and a width wider than the upper bank layer 410b. The lower bank layer 410a may be made of a hydrophilic material, but is not limited thereto, and may be made of a hydrophobic material in some cases.

[0055] The upper bank layer 410b is patterned on the lower bank layer 410a. The upper bank layer 410b is formed at the boundary between the first sub-pixel (SP1) and the second sub-pixel (SP2) and the boundary between the second sub-pixel (SP2) and the third sub-pixel (SP3). As will be seen from FIG. 7, which will be described later, the upper bank layer 410b may not be formed at the boundary between the first sub-pixels (SP1), the boundary between the second sub-pixels (SP2), or the boundary between the third sub-pixels (SP3).

[0056] The upper bank layer 410b may be patterned by a photolithography process after coating a solution containing a hydrophobic material, such as fluorine, on a hydrophilic organic insulator. Light irradiated during the photolithography process may migrate the hydrophobic material, such as fluorine, toward the upper side of the upper bank layer 410b, thereby making the upper portion of the upper bank layer 410b hydrophobic and the remaining portion hydrophilic. That is, the lower portion of the upper bank layer 410b in contact with the lower bank layer 410a may be hydrophilic, and the upper portion of the upper bank layer 410b may be hydrophobic. However, this is not necessarily limited thereto, and the entire upper bank layer 410b may be hydrophobic. In this way, the hydrophobic upper portion of the upper bank layer 410b may prevent the solution for forming the light-emitting stack 500, particularly the first layer 510, from spreading and mixing between adjacent subpixels (SP1, SP2, SP3).

[0057] The second bank 420 is formed on the boundary between the subpixels (SP1, SP2, SP3) above the first bank 410. A second layer 520 of the light-emitting stack 500 is provided between the second bank 420 and the first bank 410, so that the second bank 420 does not contact the first bank 410. The width of the second bank 420 may be smaller than the width of the first bank 410, but is not necessarily limited thereto. The light-emitting stack 500 may include multiple layers made of different materials, some of which may emit light and some of which may not, but may facilitate light emission by other layers in the light-emitting stack 500. For example, the light-emitting stack 500 may include one or more organic light-emitting stacks. The light-emitting stack 500 may also include at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, a charge generation layer, an electron transport layer, and / or an electron injection layer.

[0058] The second bank 420 may be formed using the same material and process as the upper bank layer 410b, such that the lower portion of the second bank 420 has a hydrophilic property and the upper portion of the second bank 420 has a hydrophobic property. Alternatively, the entire second bank 420 may be configured to have a hydrophobic property. In this manner, the upper portion of the second bank 420 having a hydrophobic property can prevent a solution for forming the third layer 530 of the light-emitting stack 500 from spreading and mixing between adjacent subpixels (SP1, SP2, SP3).

[0059] The light-emitting stack 500 is formed on the first electrode 300 and the banks 410, 420. The light-emitting stack 500 includes a first layer 510, a second layer 520, a third layer 530, and a fourth layer 540 stacked in order.

[0060] The first layer 510 is formed on the first electrode 300 by a solution process using an inkjet device, etc. The first layer 510 includes an emitting layer made of an organic material that emits light.

[0061] The first layer 510 is patterned into a plurality of sub-pixels (SP1, SP2, SP3) and is discontinuous between the sub-pixels (SP1, SP2, SP3). That is, the first layer 510 in the first sub-pixel (SP1), the first layer 510 in the second sub-pixel (SP2), and the first layer 510 in the third sub-pixel (SP3) are discontinuous and not connected to each other, thereby preventing light emission from occurring in the boundary regions between the sub-pixels (SP1, SP2, SP3).

[0062] Since the upper portion of the upper bank layer 410b has hydrophobic properties, the first layer 510 does not spread onto the upper bank layer 410b, and is patterned in a discontinuous manner within the plurality of sub-pixels (SP1, SP2, SP3).

[0063] The first layer 510 is formed to contact the lower bank layer 410a of the first bank 410, but although not shown in detail in the figure, it may also extend to the upper bank layer 410b of the first bank 410 and contact the side of the upper bank layer 410b.

[0064] The second layer 520 may be formed on the first layer 510 by a deposition process such as evaporation. The second layer 520 may not include an emissive stack of organic materials that emits light, but may instead include a functional layer that injects or transports electrons or a functional layer that generates charges.

[0065] The second layer 520 may be formed continuously throughout the internal regions of the sub-pixels (SP1, SP2, SP3) and their boundary regions. Therefore, the second layer 520 in the first sub-pixel (SP1), the second layer 520 in the second sub-pixel (SP2), and the second layer 520 in the third sub-pixel (SP3) are connected to each other without any discontinuities. In other words, the second layer 520 is continuous from the first sub-pixel (SP1) to the third sub-pixel (SP3). The second layer 520 may cover the entire top surface of the first bank 410.

[0066] The third layer 530 is formed on the second layer 520 by a solution process using an inkjet device, etc. The third layer 530 includes an emitting layer of organic materials that emits light.

[0067] The third layer 530 is patterned in the plurality of sub-pixels (SP1, SP2, SP3) and is discontinuous between the plurality of sub-pixels (SP1, SP2, SP3). That is, the third layer 530 in the first sub-pixel (SP1), the third layer 530 in the second sub-pixel (SP2), and the third layer 530 in the third sub-pixel (SP3) are discontinuous and not connected to each other, thereby preventing light emission from occurring in the boundary regions between the sub-pixels (SP1, SP2, SP3).

[0068] According to one embodiment of the present invention, the second bank 420 is further formed on the upper surface of the second layer 520 before forming the third layer 530 so that the third layer 530 is not continuous but is discontinuous between the plurality of sub-pixels (SP1, SP2, SP3).

[0069] In detail, the second layer 520 is formed to be continuous in the boundary regions between the sub-pixels (SP1, SP2, SP3), but the top surface of the second layer 520 does not have hydrophobic properties. Therefore, if the third layer 530 is formed on the top surface of the second layer 520 by a solution process without further forming the second bank 420, the third layer 530 may flow out into the boundary regions between the sub-pixels (SP1, SP2, SP3). In this case, since the third layer 530 is formed to be continuous between adjacent sub-pixels (SP1, SP2, SP3), a problem of light emission may occur in the boundary regions between the sub-pixels (SP1, SP2, SP3).

[0070] Therefore, in one embodiment of the present invention, the second bank 420 is further formed on the upper surface of the second layer 520, and the upper portion of the second bank 420 has hydrophobic properties, so that the third layer 530 does not spread onto the upper surface of the second bank 420 when the third layer 530 is formed by a solution process such as an inkjet process. As a result, it is possible to prevent the third layer 530 from being patterned in a discontinuous manner within the plurality of sub-pixels (SP1, SP2, SP3), which may cause light emission in the boundary regions between the plurality of sub-pixels (SP1, SP2, SP3).

[0071] The fourth layer 540 may be formed on the third layer 530 by a deposition process such as evaporation. The fourth layer 540 may not include an organic light-emitting stack that generates light, but may instead include a functional layer that injects or transports electrons. The fourth layer 540 may be formed continuously throughout the interior and boundary regions of the subpixels (SP1, SP2, SP3). Therefore, the fourth layer 540 in the first subpixel (SP1), the fourth layer 540 in the second subpixel (SP2), and the fourth layer 540 in the third subpixel (SP3) are connected to each other without any interruption. In other words, the fourth layer 540 is continuous from the first subpixel (SP1) to the third subpixel (SP3). The fourth layer 540 may cover the entire top surface of the second bank 420.

[0072] 3 is a schematic cross-sectional view of a light-emitting stack 500 according to one embodiment of the present invention. The light-emitting stack 500 may include multiple layers as well as multiple stacks and sub-stacks that are different from one another. Various embodiments of the light-emitting stack 500 are described below.

[0073] As can be seen from FIG. 3, the light-emitting stack 500 according to one embodiment of the present invention includes a first stack (1) that emits light of a first color. st Stack), a second stack (2 nd Stack), and a charge generation layer (N-CGL, P-CGL) provided between the first stack and the second stack. st The light of the first color emitted from the second stack (2 nd The light of the second color emitted from the light-emitting stack 500 may be mixed with the light of the first color emitted from the light-emitting stack 500 to emit white light.

[0074] The first stack (1 st The stack consists of a hole injection layer (HIL), a first hole transport layer (1 st HTL), 1st luminous stack (1 st EML) and the first electron transport layer (1 st ETL), nd Stack) is a second hole transport layer (2 nd HTL), second light-emitting stack (2 nd EML), second electron transport layer (2 nd The layer may comprise an electron injection layer (ETL), and an electron injection layer (EIL).

[0075] The first light-emitting stack (1 st EML) emits blue light, and the second light-emitting stack (2 nd The first light-emitting stack (1 EML) can emit yellow-green light. st EML) emits yellow-green light, and the second emitting stack (2 nd EML) can emit blue light.

[0076] The charge generation layer (N-CGL, P-CGL) comprises an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL). The N-type charge generation layer (N-CGL) is formed by stacking the first stack (1 st Stack), and st The P-type charge generation layer (P-CGL) is formed on the N-type charge generation layer (N-CGL), and the second stack (2 nd The electrons are provided to the GaN Stack.

[0077] Referring to FIG. 2, the first layer 510 formed by the solution process is the first stack (1 st In particular, the hole injection layer (HIL), the first hole transport layer (1 st HTL), and the first light-emitting stack (1 st EML).

[0078] The second layer 520 formed in the deposition process is the first stack (1 st The remaining layers of the Stack and the charge generation layer (N-CGL, P-CGL), in particular the first electron transport layer (1 st The layer may comprise an ETL, an N-type charge generation layer (N-CGL), and a P-type charge generation layer (P-CGL).

[0079] The third layer 530 formed by the solution process is nd In particular, the second hole transport layer (2 nd HTL) and the second light-emitting stack (2 nd EML).

[0080] The fourth layer 540 formed in the deposition process is the second stack (2 nd The remaining layers of the Stack may comprise the second electron transport layer (2 nd The layer may comprise an electron injection layer (ETL) and an electron injection layer (EIL).

[0081] The first light-emitting stack (1 st When the upper layer of the EML is formed by a solution process, the solvent in the solution may cause the first light-emitting stack (1 st The first light-emitting stack (1 st The upper layer of the EML may preferably be formed by a vapor deposition process. nd It may be preferable to form the upper layer of the EML by a deposition process as well. For this reason, the second layer 520 and the fourth layer 540 may be formed by a deposition process instead of a solution process.

[0082] 2, the second electrode 600 is formed on the light-emitting stack 500. The second electrode 600 may be formed continuously without interruption throughout the interior regions and boundary regions of the plurality of sub-pixels (SP1, SP2, SP3). The second electrode 600 may function as a cathode of the electroluminescent display device. If the electroluminescent display device according to the present invention is a top emission type, the second electrode 600 may be formed as a transparent electrode or a semi-transparent electrode, and if the electroluminescent display device according to the present invention is a bottom emission type, the second electrode 600 may be formed as a reflective electrode.

[0083] The encapsulation layer 700 is formed on the second electrode 600 and serves to prevent external moisture or oxygen from penetrating into the light emitting stack 500 .

[0084] The color filter 800 and the light-shielding layer 850 may be formed on the encapsulation layer 700. The color filter 800 may include a red (R) color filter disposed in a first sub-pixel (SP1), a green (G) color filter disposed in a second sub-pixel (SP2), and a blue (B) color filter disposed in a third sub-pixel (SP3). The light-shielding layer 850 may be formed in a region between the red (R), green (G), and blue (B) color filters, i.e., a boundary region between the sub-pixels (SP1, SP2, SP3).

[0085] When the electroluminescent display device according to an embodiment of the present invention is a top emission type, as shown in the drawing, the color filter 800 and the light blocking layer 850 may be formed on the upper surface of the encapsulation layer 700. However, when the electroluminescent display device according to an embodiment of the present invention is a bottom emission type, the color filter 800 and the light blocking layer 850 may be formed below the light emitting stack 500, for example, in the circuit element layer 200.

[0086] The protective layer 900 is formed on the color filter 800 and the light-blocking layer 850 to protect the internal components from external impact.

[0087] 4 to 6 are schematic cross-sectional views of electroluminescent displays according to various embodiments of the present invention.

[0088] 4 differs from the electroluminescent display device of FIG. 2 described above in that the configuration of upper bank layer 411b of first bank 410 is changed.

[0089] 4, a hole (H) is formed on the upper surface of the upper bank layer 411b of the first bank 410. Thus, the second layer 521 of the light-emitting stack 500 formed on the upper bank layer 411b extends along the inner surface of the hole (H), and the lower part of the second bank 421 formed on the second layer 521 is provided to fill the hole (H). The second layer 521 is formed by a deposition process.

[0090] According to the structure of FIG. 4, the anode of this embodiment, which is a conductive layer, can be formed by a vapor deposition process, an organic light-emitting stack can be formed directly on top of it by an inkjet printing process, a second conductive layer can be formed directly on top of it by a vapor deposition process, and a second organic light-emitting stack can be formed directly on top of it by an inkjet printing process.

[0091] According to the structure shown in FIG. 4, the hole (H) formed on the upper surface of the upper bank layer 411b increases the current path of the second layer 521 of the light-emitting stack 500, thereby reducing the occurrence of leakage current between the third sub-pixel (SP3) and the second sub-pixel (SP2).

[0092] FIG. 5 differs from the electroluminescent display device according to FIG. 4 in that the structure of the grooves (H) formed on the upper surface of the upper bank layer 412b is changed.

[0093] According to the above-mentioned FIG. 4, the holes (H) formed on the upper surface of the upper bank layer 411b are formed without penetrating the upper bank layer 411b, so that the second layer 521 of the light-emitting stack 500 only contacts the upper bank layer 411b in the area corresponding to the holes (H), but does not contact the lower bank layer 410a thereunder.

[0094] In contrast, according to FIG. 5, the hole (H) formed on the upper surface of the upper bank layer 412b is formed to penetrate the upper bank layer 412b, so that the second layer 522 of the light-emitting stack 500 contacts the lower bank layer 410a in the area corresponding to the hole (H), and the lower part of the second bank 422 formed on the second layer 522 is configured to fill the hole (H).

[0095] Compared with the structure of FIG. 4, the structure of FIG. 5 has the advantage that the current path of the second layer 522 of the light-emitting stack 500 in the home (H) region is increased, and the occurrence of leakage current between the third sub-pixel (SP3) and the second sub-pixel (SP2) is reduced.

[0096] 6 differs from the electroluminescent display device according to FIG. 5 in that the structure of the second bank 423 is changed.

[0097] According to FIG. 5, the upper surface of the second bank 422 is higher than the upper surface of the second layer 522 .

[0098] 6, the upper surface of second bank 423 is formed at the same height as the upper surface of second layer 522. Even if the upper surface of second bank 423 is formed at the same height as the upper surface of second layer 522, since the upper surface of second bank 423 has hydrophobic properties, when third layer 530 is formed by a solution process, third layer 530 can be discontinuous at the upper surface of second bank 423.

[0099] Figure 7 is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, which corresponds to a cross-section along line CD in Figure 1. That is, Figure 7 is a cross-sectional view including a boundary region between one first sub-pixel SP1 and another adjacent first sub-pixel SP1, which emit light of the same color.

[0100] As can be seen from FIG. 7, an electroluminescent display device according to one embodiment of the present invention comprises a substrate 100, a circuit element layer 200, a first electrode 300, a lower bank layer 410a, a light-emitting stack 500, a second electrode 600, an encapsulating layer 700, a color filter 800, a light-shielding layer 850, and a protective layer 900.

[0101] The configurations of the substrate 100, circuit element layer 200, first electrode 300, second electrode 600, sealing layer 700, color filter 800, light-shielding layer 850, and protective layer 900 are the same as those in Figure 2 described above, so repeated explanations will be omitted.

[0102] According to one embodiment of the present invention, only the lower bank layer 410a of the first bank 410 is formed in the boundary region between one first sub-pixel (SP1) and another adjacent first sub-pixel (SP1), and the upper bank layer 410b of the first bank 410 and the second bank 420 are not formed.

[0103] Since one first subpixel (SP1) and its adjacent first subpixel (SP1) emit light of the same hue, even if the first layer 510 of the light-emitting stack 500 and the third layer 530 of the light-emitting stack 500 are continuous between one first subpixel (SP1) and its adjacent first subpixel (SP1), there is no significant adverse effect on image quality. Therefore, the upper bank layer 410b and the second bank 420 can be omitted in the boundary region between one first subpixel (SP1) and its adjacent first subpixel (SP1).

[0104] As a result, in the boundary region between one first sub-pixel (SP1) and another first sub-pixel (SP1), the second layer 520 of the light-emitting stack 500 contacts the entire upper surface of the lower bank layer 410a. Also, in the boundary region between one first sub-pixel (SP1) and another first sub-pixel (SP1), the fourth layer 540 of the light-emitting stack 500 contacts the upper surface of the second layer 520 of the light-emitting stack 500. The fourth layer 540 can be formed by a deposition process such as sputtering.

[0105] 8 is a schematic plan view of an electroluminescent display device according to another embodiment of the present invention, which is similar to the electroluminescent display device according to FIG. 1 except that it further includes a third bank 430. Therefore, only the different configurations will be described below.

[0106] 8, the third bank 430 is formed in the boundary region between one first sub-pixel (SP1) and another adjacent first sub-pixel (SP1) that emit light of the same hue. The third bank 430 is also formed in the boundary region between one second sub-pixel (SP2) and another adjacent second sub-pixel (SP2) that emit light of the same hue. The third bank 430 is also formed in the boundary region between one third sub-pixel (SP3) and another adjacent third sub-pixel (SP3) that emit light of the same hue.

[0107] Therefore, the third bank 430 has a linear structure extending in the first direction, for example, the X-axis direction. Here, the third bank 430 does not have a continuous linear structure in the first direction, but has a discontinuous linear structure in the first direction. That is, the third bank 430 provided at the boundary between two adjacent first sub-pixels (SP1) is not connected to the third bank 430 provided at the boundary between two adjacent second sub-pixels (SP2). The third bank 430 may be discontinuous, including some parts that are separated from each other. This example can be understood from FIGS. 8 to 12.

[0108] In addition, the third bank 430 is not connected to the second bank 420. As a result, the third bank 430 is separated from the second bank 420 on one side (e.g., the left side) and the other side (e.g., the right side) of the third bank 430 with a predetermined space S1 therebetween. In other words, the third bank 430 is formed in a region between two second banks 420 on one side and the other side, excluding the predetermined space S1, in a boundary region between two adjacent first sub-pixels SP1.

[0109] The third bank 430 may be made of the same material as the second bank 420, but is not limited thereto, and may be made of a different material from the second bank 420.

[0110] Figure 9 is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, which corresponds to a cross-section taken along line EF in Figure 8. That is, Figure 9 is a cross-sectional view including a boundary region between one first sub-pixel SP1 and another first sub-pixel SP1 adjacent thereto, which emit light of the same color.

[0111] As can be seen from FIG. 9, an electroluminescent display device according to another embodiment of the present invention includes a substrate 100, a circuit element layer 200, a first electrode 300, a lower bank layer 410a, a third bank 430, a light-emitting stack 500, a second electrode 600, an encapsulating layer 700, a color filter 800, a light-shielding layer 850, and a protective layer 900.

[0112] The configurations of the substrate 100, circuit element layer 200, first electrode 300, second electrode 600, sealing layer 700, color filter 800, light-shielding layer 850, and protective layer 900 are the same as those in Figure 7 described above, so repeated explanations will be omitted.

[0113] According to another embodiment of the present invention, the lower bank layer 410a of the first bank 410 and the third bank 430 are formed in the boundary region between one first sub-pixel (SP1) and another adjacent first sub-pixel (SP1).

[0114] Here, the third bank 430 is provided between the second layer 520 and the fourth layer 540 of the light-emitting stack 500, similar to the second bank 420 described above.

[0115] As a result, in the boundary region between one first sub-pixel (SP1) and its adjacent first sub-pixel (SP1), the second layer 520 of the light-emitting stack 500 contacts the entire top surface of the lower bank layer 410a. Also, in the boundary region between one first sub-pixel (SP1) and its adjacent first sub-pixel (SP1), the fourth layer 540 of the light-emitting stack 500 contacts the top surface of the third bank 430.

[0116] Therefore, the third layer 530 of the light-emitting stack 500 formed in one first sub-pixel SP1 can be prevented from spreading to another adjacent first sub-pixel SP1 by the third bank 430. To this end, the top surface of the third bank 430 may have hydrophobic properties. However, the top surface of the third bank 430 may also be formed to have hydrophilic properties.

[0117] Referring again to FIG. 8, according to another embodiment of the present invention, the third bank 430 is configured to be separated from the second bank 420 by a predetermined space (S1). This is because, during the solution process for forming the third layer 530 of the light-emitting stack 500, the solution can move smoothly through the predetermined space (S1), thereby preventing the formation of spots.

[0118] More specifically, by forming the third bank 430, the third layer 530 of the light-emitting stack 500 can be separated between two adjacent first sub-pixels (SP1). If the third bank 430 is formed in a linear structure that is continuous in the first direction while contacting the second bank 420, the solution for forming the third layer 530 of the light-emitting stack 500 is confined within each first sub-pixel (SP1) and cannot move between adjacent first sub-pixels (SP1). In this case, if the amount of solution ejected from the inkjet cannot be precisely controlled, the amount of solution may be too much or too little in a particular first sub-pixel (SP1), resulting in mottling.

[0119] In another embodiment of the present invention, the problem of mottling can be prevented by configuring the third bank 430 to be separated from the second bank 420 by a predetermined space S1. In particular, even if the amount of solution ejected by inkjet printing cannot be accurately controlled, the solution can move between adjacent first sub-pixels SP1 via the predetermined space S1, thereby eliminating the problem of the amount of solution being too much or too little in a specific first sub-pixel SP1, and thereby preventing the problem of mottling.

[0120] 10 to 12 are schematic plan views of electroluminescent display devices according to various embodiments of the present invention, which differ from the electroluminescent display device according to FIG. 8 described above in that the configuration of the third bank 430 and the predetermined space (S2) is changed.

[0121] As in the above-described FIG. 8, in the cases of FIGS. 10 to 12, the third bank 430 is formed in the area between two second banks 420 on one side and the other side, excluding a predetermined space (S2) in the boundary area between two adjacent first sub-pixels (SP1).

[0122] Here, according to FIG. 10, the third bank 430a on one side (e.g., the left side) extends from the second bank 420 on one side (e.g., the left side) toward the other side (e.g., the right side), and the third bank 430b on the other side (e.g., the right side) extends from the second bank 420 on the other side (e.g., the right side) toward one side (e.g., the left side), and the third bank 430a on one side is separated from the third bank 430b on the other side by a predetermined space (S).

[0123] According to FIG. 11, multiple third banks 430 are spaced apart from each other with a predetermined space (S3) between them, and the third banks 430 located on the furthest side (e.g., the left side) and the furthest side (e.g., the right side) are spaced apart from the second banks 420 with a predetermined space (S4) between them.

[0124] Referring to FIG. 12, the third bank 430 extends from the second bank 420 on one side (e.g., the left side) toward the other side (e.g., the right side), and the third bank 430 is not connected to the second bank 420 on the other side (e.g., the right side), but is separated from it by a predetermined space (S5).

[0125] As described above, the positions of the predetermined spaces (S1, S2, S3, S4, S5) in the boundary region between two adjacent first sub-pixels (SP1) can be changed in various ways.

[0126] Although the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments and can be embodied in various modifications without departing from the spirit of the present invention. Therefore, the disclosed embodiments are intended to illustrate, rather than limit, the spirit of the present invention, and the scope of the spirit of the present invention is not limited by these embodiments. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not restrictive. The scope of the present invention should be interpreted by the scope of the claims, and all technical concepts within the scope equivalent thereto should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0127] 100: Substrate 200: Circuit element layer 300: 1st electrode 410: First Bank 420: Second Bank 430: 3rd Bank 500: Glow stack 510, 520, 530, 540: 1st, 2nd, 3rd, 4th layer 600: 2nd electrode 700: Sealing layer 800: Color filter 850: Light blocking layer 900: Protective layer

Claims

1. a substrate including a plurality of first sub-pixels and a plurality of second sub-pixels; a first electrode provided on the substrate in each of the first sub-pixels and the second sub-pixels, and a light-emitting stack provided on the first electrode; a second electrode disposed on the light-emitting stack; first banks provided at boundaries between the plurality of first sub-pixels and the plurality of second sub-pixels, at boundaries between the plurality of first sub-pixels, and at boundaries between the plurality of second sub-pixels; a second bank provided on the first bank along a boundary between the plurality of first sub-pixels and the plurality of second sub-pixels; third banks provided in a discontinuous linear structure at boundaries between the plurality of first sub-pixels and at boundaries between the plurality of second sub-pixels; the light-emitting stack includes a first layer provided in each of the plurality of first sub-pixels and the plurality of second sub-pixels, and a second layer provided on the first layer and continuous from the first sub-pixel to the adjacent second sub-pixel; the first bank is provided below the second layer, and the second bank is provided above the second layer; the first layer provided in one first sub-pixel among the plurality of first sub-pixels and the first layer provided in another first sub-pixel adjacent to the one first sub-pixel are spaced apart from each other via the first bank; the second layer provided in the one first sub-pixel and the second layer provided in the other first sub-pixel are provided continuously between the first bank and the third bank, the first layer provided in the one first sub-pixel and the first layer provided in the second sub-pixel are spaced apart from each other via the first bank; the second layer provided in the one first sub-pixel and the second layer provided in the second sub-pixel are provided continuously between the first bank and the second bank.

2. The electroluminescent display device of claim 1 , wherein the third bank is provided in a region excluding a predetermined space in a boundary region between the plurality of first sub-pixels.

3. The electroluminescent display device of claim 2 , wherein the third bank is separated from the second bank with the predetermined space therebetween.

4. The electroluminescent display device of claim 2 , wherein the third bank contacts the second bank and extends from the second bank.

5. The light-emitting stack further includes a third layer on the second layer provided in each of the first sub-pixel and the second sub-pixel, and a fourth layer on the third layer provided in each of the first sub-pixel and the second sub-pixel, the first layer and the third layer are provided so as to be discontinuous in each of the first sub-pixels and the second sub-pixels, The electroluminescent display device of claim 1 , wherein the second layer and the fourth layer are provided continuously from the plurality of first sub-pixels to the plurality of second sub-pixels.

6. the first bank and the second bank are spaced apart from each other above and below the second layer, The electroluminescent display device of claim 5 , wherein the first bank and the third bank are spaced apart from each other across the second layer.

7. a substrate including first and second sub-pixels arranged in a first direction; a first electrode provided on the substrate in each of the first sub-pixel and the second sub-pixel; a first portion of a first light-emitting stack disposed on the first electrode; a second portion of the first light-emitting stack spaced apart from the first portion of the first light-emitting stack in a first direction and disposed on the first electrode; a first bank disposed between a first portion of the first light-emitting stack and a second portion of the first light-emitting stack; a conductive layer disposed on the first bank, the first portion of the first light-emitting stack, and the second portion of the first light-emitting stack; a first portion of a second light emitting stack disposed on the conductive layer; a second portion of the second light-emitting stack spaced apart from the first portion of the second light-emitting stack in the first direction and disposed on the conductive layer; the first and second portions of the first light-emitting stack overlap with the first and second portions of the second light-emitting stack; a third portion of the first and second light-emitting stacks spaced apart in a second direction from the first portion of the first and second light-emitting stacks, the third portion of the first light-emitting stack being disposed below the conductive layer and the third portion of the second light-emitting stack being disposed on the conductive layer; a second bank disposed on the conductive layer and disposed between the first portion of the second light-emitting stack and the second portion of the second light-emitting stack; a third bank provided in a region excluding a predetermined space in a boundary region between the first portion of the second light-emitting stack and the third portion of the second light-emitting stack; a second electrode disposed on the first to third portions of the second light-emitting stack; a first portion of the second light-emitting stack associated with a first sub-pixel, and a third portion of the second light-emitting stack associated with another first sub-pixel that emits light of the same hue as the first sub-pixel; the third bank is provided in a region excluding a predetermined space in a boundary region between the first sub-pixel and the another first sub-pixel, the third portion of the first light-emitting stack and the first portion of the first light-emitting stack are spaced apart from each other via the first bank; the conductive layer on the third portion of the first light-emitting stack and the conductive layer on the first portion of the first light-emitting stack are continuously provided between the first bank and the third bank; the second portion of the first light-emitting stack and the first portion of the first light-emitting stack are spaced apart from each other via the first bank; the conductive layer on the second portion of the first light-emitting stack and the conductive layer on the first portion of the first light-emitting stack are provided continuously between the first bank and the second bank.

8. The electroluminescent display device of claim 7 , wherein the conductive layer is a charge generating layer.

9. The electroluminescent display device of claim 7 , wherein a first portion of the first light-emitting stack is associated with the first sub-pixel, and a second portion of the first light-emitting stack is associated with a second sub-pixel.

10. a first color filter disposed on a first portion of the first light-emitting stack; The electroluminescent display device of claim 7 , further comprising: a second color filter disposed on the second portion of the first light-emitting stack.

11. The electroluminescent display device according to claim 7 , wherein the second bank is provided on the conductive layer.

12. The electroluminescent display device of claim 7 , wherein the height of the first bank is greater than the height of the first portion of the first light-emitting stack.

13. The electroluminescent display device of claim 7 , wherein the first bank includes a hole, and the conductive layer extends along an inner surface of the hole.

14. The electroluminescent display device of claim 7 , further comprising a thin film transistor disposed on the substrate, the first portion of the first light-emitting stack being disposed on the thin film transistor.

15. The electroluminescent display device of claim 7, wherein the first bank includes one of an insulating material and a hydrophobic material.

16. 8. The electroluminescent display device of claim 7, wherein the first portion of the first light-emitting stack is disposed within the first sub-pixel, and the second portion of the first light-emitting stack is disposed within a second sub-pixel spaced apart from the first sub-pixel.

Images