Electroluminescent display device

Abstract

Provided is an electroluminescent display device including: a substrate including a first sub-pixel and a second sub-pixel; a first electrode in each of the first sub-pixel and the second sub-pixel on the substrate; a light-emitting portion on the first electrode; and a second electrode on the light-emitting portion, wherein the light-emitting portion includes a hole transport layer, a first light-emitting layer provided in the first sub-pixel, a second light-emitting layer provided in the second sub-pixel, and an electron transport layer, wherein the second light-emitting layer extends to the first sub-pixel and is provided below the first light-emitting layer, and wherein the hole transport layer is provided between the second light-emitting layer and the first light-emitting layer in the first sub-pixel.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2024-0173129, filed on November 28, 2024, which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to an electroluminescent display device. Background Technology

[0004] An electroluminescent display device includes a first electrode, a second electrode, and a light-emitting layer disposed between the first electrode and the second electrode, and displays an image by emitting light through the light-emitting layer using the electric field between the first electrode and the second electrode.

[0005] The electroluminescent display device includes: a red subpixel, a green subpixel, and a blue subpixel; and an emissive layer disposed in each subpixel.

[0006] A light-emitting layer is formed in each sub-pixel using a deposition process that utilizes a mask.

[0007] However, due to limitations in the deposition process, the emitting layer can be deposited not only in the corresponding sub-pixel but also in other sub-pixels adjacent to the corresponding sub-pixel. Therefore, there is a problem of color change in light emitted from other sub-pixels.

[0008] In particular, the color change of light emitted from a side viewpoint is greater than the color change of light emitted from a front viewpoint. Summary of the Invention

[0009] The present invention was made in view of the above problems, and one aspect of the present invention is to provide an electroluminescent display device that can solve the problem of color variation of light emitted from both the front viewing angle and the side viewing angle, even when the light-emitting layer is deposited not only in the corresponding sub-pixel but also in other sub-pixels adjacent to the corresponding sub-pixel.

[0010] According to one aspect of the present invention, the above and other technical effects can be achieved by providing an electroluminescent display device, the electroluminescent display device comprising: a substrate, the substrate including a first sub-pixel and a second sub-pixel; a first electrode in each of the first sub-pixel and the second sub-pixel on the substrate; a light-emitting portion on the first electrode; and a second electrode on the light-emitting portion, wherein the light-emitting portion includes a hole transport layer, a first light-emitting layer disposed in the first sub-pixel, a second light-emitting layer disposed in the second sub-pixel, and an electron transport layer, wherein the second light-emitting layer extends to the first sub-pixel and is disposed below the first light-emitting layer, and wherein the hole transport layer is disposed between the second light-emitting layer and the first light-emitting layer in the first sub-pixel.

[0011] Furthermore, according to one aspect of the present invention, the above and other technical effects can be achieved by providing an electroluminescent display device, the electroluminescent display device comprising: a red sub-pixel including a red emitting layer; a green sub-pixel including a green emitting layer; a blue sub-pixel including a blue emitting layer; a first hole transport layer disposed in the red sub-pixel, the green sub-pixel, and the blue sub-pixel, and disposed below the red emitting layer, the green emitting layer, and the blue emitting layer; a second-first hole transport layer disposed between the first hole transport layer and the green emitting layer; and a second-second hole transport layer disposed between the first hole transport layer and the red emitting layer, wherein the green emitting layer extends to the red sub-pixel and is disposed below the red emitting layer, and wherein the second-second hole transport layer is disposed between the green emitting layer and the red emitting layer.

[0012] Furthermore, according to one aspect of the present invention, the above and other technical effects can be achieved by providing an electroluminescent display device, the electroluminescent display device comprising: a red sub-pixel including a red emitting layer; a green sub-pixel including a green emitting layer; a blue sub-pixel including a blue emitting layer; a first hole transport layer disposed in the red sub-pixel, the green sub-pixel, and the blue sub-pixel, and disposed below the red emitting layer, the green emitting layer, and the blue emitting layer; a second-first hole transport layer disposed between the first hole transport layer and the green emitting layer; and a second-second hole transport layer disposed between the first hole transport layer and the red emitting layer, wherein the blue emitting layer extends to the green sub-pixel and is disposed below the green emitting layer, and wherein the second-first hole transport layer is disposed between the green emitting layer and the blue emitting layer.

[0013] It should be understood that the foregoing general description and the following specific description are exemplary and explanatory, and are intended to provide further explanation of the claimed inventive concept. Attached Figure Description

[0014] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the invention and, together with the description, explain the principles of the invention. In the drawings:

[0015] Figure 1A and Figure 1B The spectrum is shown according to the wavelength band of the emitting layer, and is a graph showing the change of EL (electroluminescence) spectrum according to the viewing angle in the red wavelength band of the red emitting layer. Figure 1A This is the EL spectrum of the red emitting layer from a frontal viewing angle. Figure 1B This is the EL spectrum of the red emitting layer from a side view.

[0016] Figure 2A and Figure 2B The spectrum is shown according to the wavelength band of the emitting layer, and is a graph showing the change of EL (electroluminescence) spectrum according to the viewing angle in the green wavelength band of the green emitting layer. Figure 2A This is the EL spectrum of the green emitting layer from a frontal viewing angle. Figure 2B This is the EL spectrum of the green emitting layer from a side view.

[0017] Figure 3A and Figure 3B The spectrum is shown according to the wavelength band of the emitting layer, and is a graph showing the change of the EL (electroluminescence) spectrum according to the viewing angle in the blue wavelength band of the blue emitting layer. Figure 3A This is the EL spectrum of the blue emitting layer from a frontal viewing angle. Figure 3B This is the EL spectrum of the blue emitting layer from a side view.

[0018] Figure 4 This is a plan view showing the pixel structure of an electroluminescent display device according to an embodiment of the present invention.

[0019] Figure 5 This is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, showing red sub-pixels and green sub-pixels that are adjacent to each other.

[0020] Figure 6 This is an energy band diagram of the light-emitting portion of the red sub-pixel according to an embodiment of the present invention.

[0021] Figure 7 This is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, showing red sub-pixels and green sub-pixels that are adjacent to each other.

[0022] Figure 8 This is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, showing green and blue sub-pixels adjacent to each other.

[0023] Figure 9 This is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, showing green sub-pixels and blue sub-pixels that are adjacent to each other.

[0024] Figure 10 This is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, showing red and blue sub-pixels that are adjacent to each other.

[0025] Figure 11 This is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, showing red sub-pixels and blue sub-pixels that are adjacent to each other.

[0026] Figure 12A It is based on the EL spectrum of the red sub-pixel of the comparative example. Figure 12B This is the EL spectrum of the red sub-pixel according to an embodiment of the present invention.

[0027] Throughout the accompanying drawings and detailed description, unless otherwise described, the same reference numerals should be understood to refer to the same elements, features, and structures. For purposes of clarity, illustrative purposes, and convenience, the relative dimensions and depictions of these elements may be exaggerated. Detailed Implementation

[0028] Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. The described process steps and / or operations are exemplary; however, the order of steps and / or operations is not limited to the order set forth herein, but may be varied as is known in the art, unless the steps and / or operations must occur in a specific order. The names of the corresponding elements used in the following explanation may be chosen solely for ease of writing and may therefore differ from the names used in actual products.

[0029] The advantages and features of the present invention, as well as its implementation methods, will be illustrated by the following description of embodiments with reference to the accompanying drawings. However, the present invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. More precisely, these embodiments are provided so that the disclosure of the present invention is thorough and complete, and fully conveys the scope of the invention to those skilled in the art. Furthermore, the present invention is defined only by the scope of the claims.

[0030] The shapes, dimensions, ratios, angles, and quantities disclosed in the accompanying drawings to describe embodiments of the invention are merely examples, and therefore the invention is not limited to the details shown. Throughout the specification, similar reference numerals denote similar elements. In the following description, detailed descriptions of related known functions or configurations will be omitted where it is determined that such detailed descriptions would unnecessarily obscure the focus of the invention. Where terms such as "comprising," "having," and "including" are used in the invention, additional parts may be added unless "only" is used. Singular terms may include plural forms unless otherwise specified.

[0031] When interpreting components, even if there is no separate explicit description of the error range, it is interpreted as including the error range.

[0032] When describing positional relationships, for example, when the positional relationship is described as "above," "upper," "below," and "next," one or more parts may be positioned between two other parts, unless "exactly" or "directly" is used. Terms such as "below," "lower," "above," and "upper" are used herein to describe relationships between elements as shown in the figures. It will be understood that these terms are spatially relative and based on the orientation depicted in the figures.

[0033] The description of temporal relationships may include cases where the temporal sequence is described as “after,” “following,” or “before,” and is not sequential, unless “exactly” or “directly” is used.

[0034] Although terms like "first," "second," etc., are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, the "first component" mentioned below can be the "second component" within the technical concept of this invention.

[0035] It will be understood that although the terms “first,” “second,” “A,” “B,” “(a),” and “(b)” are used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element without departing from the scope of the invention, and similarly, a second element may be referred to as a first element.

[0036] If a component is described as “connected,” “joined,” “linked,” or “attached” to another component, then that component may be directly connected, joined, linked, or attached to that other component. However, it should be understood that, in the absence of any particular description, other components may be inserted between each component that may be indirectly connected, joined, linked, or attached.

[0037] It should be understood that if a component or layer is stated as "overlapping" with another component or layer, then that component or layer may be in direct contact with or overlap with the other component or layer, but unless otherwise explicitly described, other components may be inserted between each component that may overlap indirectly.

[0038] The term “at least one” should be understood to include any and all combinations of one or more of the related listed items. For example, “at least one of the first element, the second element and the third element” means a combination of all three listed elements, a combination of any two of the three elements, and each individual element, namely the first element, the second element or the third element.

[0039] The terms “first direction,” “second direction,” “third direction,” “X-axis direction,” “Y-axis direction,” and “Z-axis direction” should not be interpreted merely as geometrically perpendicular to each other, but can mean that the construction of the invention has a wider directional range within the scope of its functional effectiveness.

[0040] Features of each of the various embodiments in this specification may be partially or completely combined or integrated with each other, various technical interactions and drives are possible, and each embodiment may be implemented independently of each other or may be implemented together in an associated relationship.

[0041] In the following, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0042] Figure 1A and Figure 1B The spectrum is shown according to the wavelength band of the emitting layer, and is a graph showing the change of EL (electroluminescence) spectrum according to the viewing angle in the red wavelength band of the red emitting layer. Figure 1A It is the EL spectrum from the front viewpoint, and Figure 1B This refers to the EL spectrum viewed from a side angle. In this invention, the side angle is a 60-degree angle.

[0043] from Figure 1A and Figure 1B It can be seen that the PL (photoluminescence) spectrum in the blue wavelength band of the blue (B) emitting layer and the PL spectrum in the green wavelength band of the green (G) emitting layer overlap with each other in some wavelength bands. The PL spectrum in the green wavelength band of the green (G) emitting layer and the PL spectrum in the red wavelength band of the red (R) emitting layer overlap with each other in some wavelength bands. However, the PL spectrum in the blue wavelength band of the blue (B) emitting layer and the PL spectrum in the red wavelength band of the red (R) emitting layer may not overlap.

[0044] The product of the PL spectrum and the OC (output coupling curve) spectrum in the red wavelength band of the red (R) emitting layer, which are designed with consideration of the microcavity characteristics, ultimately becomes the EL spectrum in the red wavelength band of the red (R) emitting layer.

[0045] like Figure 1A As shown, the OC spectrum does not change at the front viewing angle, but as... Figure 1B As shown, the OC spectrum shifts toward shorter wavelengths at the side viewpoint.

[0046] In this way, when the OC spectrum in the red wavelength band shifts towards shorter wavelengths, the peak wavelength of the EL spectrum in the red wavelength band also shifts towards shorter wavelengths, and the intensity of the peak wavelength decreases. Furthermore, the OC spectrum in the red wavelength band still does not overlap with the PL spectrum in the blue wavelength band of the blue (B) emitting layer, but the overlap area between the OC spectrum in the red wavelength band and the PL spectrum in the green wavelength band of the green (G) emitting layer increases.

[0047] Therefore, if the green (G) emitting layer emits light in the red sub-pixel, the color of the emitted red light is not a major problem when viewed from the front, but the color of the emitted red light changes when viewed from the side.

[0048] As a result, from Figure 1A and Figure 1B As can be seen, if the blue emitting layer emits light in the red sub-pixel, there is no problem with the red light emitted from the red sub-pixel. However, if the green emitting layer emits light, there is a color change problem with the red light emitted from the side view.

[0049] According to an embodiment of the present invention, even when the green light-emitting layer emits light in the red sub-pixel, the color of the red light emitted from the side view will not change, as will be described later.

[0050] Figure 2A and Figure 2B The spectrum is shown according to the wavelength band of the emitting layer, and is a graph showing the change of EL (electroluminescence) spectrum according to the viewing angle in the green wavelength band of the green emitting layer. Figure 2A It is the EL spectrum from the front viewpoint, and Figure 2B This is the EL spectrum viewed from the side.

[0051] from Figure 2A and Figure 2B It can be seen that the product of the PL spectrum and the OC (output coupling curve) spectrum in the green wavelength band of the green (G) emitting layer, which is set considering the microcavity characteristics, ultimately becomes the EL spectrum in the green wavelength band of the green (G) emitting layer.

[0052] like Figure 2A As shown, the OC spectrum does not change at the front viewing angle, but as... Figure 2B As shown, the OC spectrum shifts toward shorter wavelengths at the side viewpoint.

[0053] In this way, when the OC spectrum in the green wavelength band shifts towards shorter wavelengths, the peak wavelength of the EL spectrum in the green wavelength band also shifts towards shorter wavelengths, and the intensity of the peak wavelength decreases. Furthermore, the overlap area between the OC spectrum in the green wavelength band and the PL spectrum in the red wavelength band of the red (R) emitting layer does not increase, but the overlap area between the OC spectrum in the green wavelength band and the PL spectrum in the blue wavelength band of the blue (B) emitting layer increases.

[0054] Therefore, if the blue (B) emitting layer emits light in the green sub-pixel, the color of the green light emitted from the front view is not a big problem, but the green light emitted from the side view has a color change problem.

[0055] As a result, from Figure 2A and Figure 2B It is evident that if the red emitting layer emits light within the green sub-pixel, the green light emitted from the green sub-pixel is without issue. However, if the blue emitting layer emits light, the green light emitted from the side view exhibits a color change.

[0056] According to an embodiment of the present invention, even when the blue light-emitting layer emits light in the green sub-pixel, the color of the green light emitted from the side view will not change, as will be described later.

[0057] Figure 3A and Figure 3B The spectrum is shown according to the wavelength band of the emitting layer, and is a graph showing the change of the EL (electroluminescence) spectrum according to the viewing angle in the blue wavelength band of the blue emitting layer. Figure 3A It is the EL spectrum from the front viewpoint, and Figure 3B This is the EL spectrum viewed from the side.

[0058] from Figure 3A and Figure 3B It can be seen that the product of the PL spectrum and the OC (output coupling curve) spectrum in the blue wavelength band of the blue (B) emitting layer, which is set considering the microcavity characteristics, ultimately becomes the EL spectrum in the blue wavelength band of the blue (B) emitting layer.

[0059] like Figure 3A As shown, the OC spectrum does not change at the front viewing angle, but as... Figure 3B As shown, the OC spectrum shifts toward shorter wavelengths at the side viewpoint.

[0060] In this way, when the OC spectrum in the blue wavelength band shifts towards shorter wavelengths, the peak wavelength of the EL spectrum in the blue wavelength band also shifts towards shorter wavelengths, and the intensity of the peak wavelength decreases. However, the OC spectrum in the blue wavelength band does not overlap with the PL spectrum in the green wavelength band of the green (G) emitting layer and the PL spectrum in the red wavelength band of the red (R) emitting layer.

[0061] Therefore, if the red (R) or green (G) emitting layer emits light in the blue sub-pixel, there is no major problem with the color of the emitted blue light.

[0062] Figure 4 This is a plan view showing the pixel structure of an electroluminescent display device according to an embodiment of the present invention.

[0063] like Figure 4 As shown, the electroluminescent display device according to the present invention includes a plurality of pixels P. Each pixel P includes a first sub-pixel SP1, a second sub-pixel SP2, and a third sub-pixel SP3.

[0064] The first sub-pixel SP1 may be spaced apart from the second sub-pixel SP2 and the third sub-pixel SP3 in a first direction (e.g., in the horizontal direction). The first sub-pixel SP1 may be disposed on one side, and for example, disposed to the left of the second sub-pixel SP2 and the third sub-pixel SP3 so as to face each of the second sub-pixel SP2 and the third sub-pixel SP3.

[0065] The second sub-pixel SP2 and the third sub-pixel SP3 may be spaced apart from each other in a second direction (e.g., in the vertical direction).

[0066] The area of ​​the first sub-pixel SP1 may be larger than the area of ​​the second sub-pixel SP2 and the area of ​​the third sub-pixel SP3, and the area of ​​the second sub-pixel SP2 may be larger than the area of ​​the third sub-pixel SP3, but is not limited thereto.

[0067] The first sub-pixel SP1 can be formed by a blue sub-pixel, the second sub-pixel SP2 can be formed by a green sub-pixel, and the third sub-pixel SP3 can be formed by a red sub-pixel, but is not limited to these.

[0068] Although not shown, each pixel P may also include a fourth sub-pixel. Furthermore, the arrangement of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3 may be varied.

[0069] According to embodiments of the present invention, a light-emitting layer can be formed in each of the sub-pixels SP1, SP2, and SP3 by a deposition process. For example, a blue light-emitting layer can be deposited in the first sub-pixel SP1, a green light-emitting layer can be deposited in the second sub-pixel SP2, and a red light-emitting layer can be deposited in the third sub-pixel SP3.

[0070] At this point, blue, green, and red emitting layers can be formed using a deposition process with a mask such as an FMM (fine metal mask). Due to the nature of the process, it may be difficult to precisely pattern the emitting layers in each of sub-pixels SP1, SP2, and SP3. Therefore, the emitting layers can be formed to extend not only to the corresponding sub-pixel but also to the sub-pixels adjacent to the corresponding sub-pixel.

[0071] For example, when a blue emitting layer is formed in a blue sub-pixel using a deposition process with an FMM mask, the deposited blue emitting layer can penetrate below the ends of the FMM mask and is movable. In this case, the blue emitting layer can extend into the red or green sub-pixels adjacent to the blue sub-pixel. Therefore, the blue emitting layer can be formed to extend not only to the blue sub-pixel but also to the adjacent red or green sub-pixels. Similarly, the red emitting layer can extend not only to the red sub-pixel but also to the adjacent green or blue sub-pixels, and the green emitting layer can extend not only to the green sub-pixel but also to the adjacent red or blue sub-pixels.

[0072] like Figure 1A and Figure 1B As shown, when the green emitting layer extends to the red sub-pixel, a color change may occur in the red light emitted from a side view. Figure 2A and Figure 2B As shown, when the blue emitting layer extends to the green sub-pixel, a color change may occur in the green light emitted from a side view. Therefore, a method is needed to prevent the aforementioned color change, and various embodiments of the present invention that meet the above requirements will be described below.

[0073] Figure 5 This is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, showing red sub-pixels (R sub-pixels) and green sub-pixels (G sub-pixels) that are adjacent to each other. Figure 5 Corresponding to one implementation method Figure 4 The cross-section of line AA.

[0074] like Figure 5 As shown, the electroluminescent display device according to an embodiment of the present invention includes a substrate 100, a circuit element layer 200, a passivation layer 310, a planarization layer 320, a first electrode 400, a dam portion 450, a light-emitting portion 500, and a second electrode 600.

[0075] The substrate 100 may be made of glass, plastic, or semiconductor material, but is not limited thereto. The electroluminescent display device according to an embodiment of the present invention may be made of a top-emitting type, therefore, both transparent and opaque materials can be used as materials for the substrate 100.

[0076] The circuit element layer 200 is disposed on the substrate 100.

[0077] The circuit element layer 200 includes driving thin-film transistors disposed in each sub-pixel (R sub-pixel, G sub-pixel).

[0078] The driving thin-film transistor includes: an active layer 210 on a substrate 100; a gate insulating layer 220 on the active layer 210; a gate 230 on the gate insulating layer 220; an interlayer insulating layer 240 on the gate 230; and a source 250 and a drain 260 on the interlayer insulating layer 240.

[0079] The source 250 and drain 260 are connected to one side and the other side of the active layer 210 through holes provided in the interlayer insulating layer 240 and the gate insulating layer 220.

[0080] Although a driving thin-film transistor with a top-gate structure having a gate 230 disposed on the active layer 210 is shown in the accompanying drawings, the present invention may include a driving thin-film transistor with a bottom-gate structure having a gate 230 disposed below the active layer 210. Furthermore, although the gate insulating layer 220 is formed over the entire surface of the substrate 100, the gate insulating layer 220 may be patterned below the gate 230 in the same manner as the gate 230. The driving thin-film transistor may be modified to various forms known in the art.

[0081] In addition, although not shown, the circuit element layer 200 may also include: 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.

[0082] The thin-film transistor is switched according to the gate signal provided to the gate line so as to supply the data voltage supplied from the data line to the driving thin-film transistor.

[0083] The driving thin-film transistor switches according to the data voltage supplied from the switching thin-film transistor to generate a data current according to the power supply supplied from the power line, and supplies the data current to the first electrode 400.

[0084] The sensing thin-film transistor senses the threshold voltage deviation that causes image quality degradation, and in response to a sensing control signal supplied from the gate line or a separate sensing line, the current driving the thin-film transistor is supplied to the reference line.

[0085] The capacitor maintains the data voltage supplied to the driving thin-film transistor for one frame and is connected to the gate terminal and source terminal of the driving thin-film transistor, respectively.

[0086] A passivation layer 310 is disposed on the circuit element layer 200. Specifically, the passivation layer 310 is disposed on the source 250 and the drain 260. The passivation layer 310 may be formed of an inorganic insulating material, but is not limited thereto.

[0087] A planarization layer 320 is disposed on the passivation layer 310. The planarization layer 320 may be made of an organic insulating material.

[0088] The passivation layer 310 and the planarization layer 320 include contact holes through which the source electrode 250 is exposed, and the first electrode 400 can be connected to the source electrode 250 exposed through the contact holes. In some cases, the drain electrode 260 can be exposed through contact holes provided in the passivation layer 310 and the planarization layer 320, and the first electrode 400 can be connected to the drain electrode 260 exposed through the contact holes.

[0089] The first electrode 400 is disposed on the planarization layer 320 in the red sub-pixel (R sub-pixel) and the green sub-pixel (G sub-pixel).

[0090] The first electrode 400 is connected to the source electrode 250 or the drain electrode 260 through contact holes provided in the passivation layer 310 and the planarization layer 320.

[0091] An electroluminescent display device according to an embodiment of the present invention may be formed of a top-emitting type, therefore, the first electrode 400 may include a reflective electrode.

[0092] The embankment 450 is disposed on the planarization layer 320 and is located at the boundary between the red sub-pixel (R sub-pixel) and the green sub-pixel (R sub-pixel).

[0093] A dam 450 is disposed on the first electrode 400 to cover the edge of the first electrode 400. Light-emitting areas R-EA and G-EA may be defined by the dam 450. Specifically, portions of the first electrode 400 exposed but not covered by the dam 450 may be designated as light-emitting areas R-EA and G-EA. Therefore, the red light-emitting area R-EA may be disposed in a red sub-pixel (R sub-pixel or first sub-pixel), and the green light-emitting area G-EA may be disposed in a green sub-pixel (G sub-pixel or second sub-pixel). The light-emitting layer of the first sub-pixel may emit light with a longer wavelength than the light-emitting layer of the second sub-pixel.

[0094] A light-emitting portion 500 is disposed in the light-emitting areas R-EA and G-EA defined by the embankment 450. The light-emitting portion 500 is disposed on the first electrode 400, and in particular, on the portion of the first electrode 400 that is exposed and not covered by the embankment 450. Alternatively, the light-emitting portion 500 may be disposed on the upper surface of the embankment 450.

[0095] The light-emitting unit 500 includes a hole injection layer HIL, a first hole transport layer HTL1, second hole transport layers HTL2-2(R) and HTL2-1(G) (also referred to as additional hole transport layers), light-emitting layers EML(R) and EML(G), an electron transport layer ETL and an electron injection layer EIL.

[0096] The hole injection layer HIL is disposed on the first electrode 400 and the embankment 450, and is formed as a continuous layer without being interrupted in the red sub-pixel (R sub-pixel) and green sub-pixel (G sub-pixel).

[0097] The first hole transport layer HTL1 is disposed on the hole injection layer HIL and is formed as a continuous layer without being broken in the red sub-pixel (R sub-pixel) and green sub-pixel (G sub-pixel).

[0098] The second hole transport layers HTL2-2(R) and HTL2-1(G) are disposed on the first hole transport layer HTL1. The second hole transport layers HTL2-2(R) and HTL2-1(G) may be formed of the same material as the first hole transport layer HTL1, but may also be formed of different materials.

[0099] The second hole transport layers HTL2-2(R) and HTL2-1(G) include the second-1 hole transport layer HTL2-1(G) disposed in the green sub-pixel (G sub-pixel) and the second-2 hole transport layer HTL2-2(R) disposed in the red sub-pixel (R sub-pixel).

[0100] Hole transport layer 2-1 (HTL2-1(G)) obtains a microcavity effect in the green sub-pixel (G sub-pixel), and hole transport layer 2-2 (HTL2-2(R)) obtains a microcavity effect in the red sub-pixel (R sub-pixel).

[0101] Considering that red light has a longer wavelength than green light, the thickness of the second-second hole transport layer HTL2-2(R) can be thicker than the thickness of the second-first hole transport layer HTL2-1(G).

[0102] The second-first hole transport layer HTL2-1(G) can be formed by a deposition process using a mask. In this case, the second-first hole transport layer HTL2-1(G) can not only be formed in the green sub-pixel (G sub-pixel), but also extend to the red sub-pixel (R sub-pixel) adjacent to the green sub-pixel (G sub-pixel) and be located below the red emitting layer EML(R). For example, the second-first hole transport layer HTL2-1(G) can extend to the region overlapping with the red emitting region R-EA of the red sub-pixel (R sub-pixel).

[0103] The thickness of the extension of the 2-1 hole transport layer HTL2-1(G) extending to the red sub-pixel (R sub-pixel) can be thinner than the thickness of the 2-1 hole transport layer HTL2-1(G) set in the green sub-pixel (G sub-pixel).

[0104] The second-second hole transport layer HTL2-2(R) can be formed using a mask deposition process. In this case, the second-second hole transport layer HTL2-2(R) can be formed not only in the red sub-pixel (R sub-pixel) but also extend to the green sub-pixel (G sub-pixel) adjacent to the red sub-pixel (R sub-pixel). For example, the second-second hole transport layer HTL2-2(R) can extend to the region overlapping with the green emitting region G-EA of the green sub-pixel (G sub-pixel).

[0105] The thickness of the extension of the 2-2 hole transport layer HTL2-2(R) extending to the green sub-pixel (G sub-pixel) can be thinner than the thickness of the 2-2 hole transport layer HTL2-2(R) set in the red sub-pixel (R sub-pixel).

[0106] In the following implementation, when the second hole transport layer disposed in one sub-pixel extends to another adjacent sub-pixel, the thickness of the extended portion of the second hole transport layer extending to the other adjacent sub-pixel may be thinner than the thickness of the second hole transport layer disposed in one sub-pixel.

[0107] According to an embodiment of the present invention, the second-first hole transport layer HTL2-1(G) may be deposited and formed before the second-second hole transport layer HTL2-2(R), and therefore, the second-first hole transport layer HTL2-1(G) may be disposed below the second-second hole transport layer HTL2-2(R).

[0108] The light-emitting layers EML(R) and EML(G) are disposed on the second hole transport layers HTL2-1(G) and HTL2-2(R).

[0109] The emissive layers EML(R) and EML(G) include a green emissive layer EML(G) disposed in the green sub-pixel (G sub-pixel) and a red emissive layer EML(R) disposed in the red sub-pixel (R sub-pixel).

[0110] Similar to the hole transport layer HTL2-1(G) of type 2-1, the green emitting layer EML(G) can be formed by a deposition process using a mask. In this case, the green emitting layer EML(G) can not only be formed in the green sub-pixels (G sub-pixels), but can also extend to the red sub-pixels (R sub-pixels) adjacent to the green sub-pixels (G sub-pixels). For example, the green emitting layer EML(G) can extend to the region overlapping with the red emitting area R-EA of the red sub-pixels (R sub-pixels) or extend to the red emitting area R-EA of the red sub-pixels (R sub-pixels).

[0111] The thickness of the extended portion of the green emitting layer EML(G) extending into the red sub-pixel (R sub-pixel) can be thinner than the thickness of the green emitting layer EML(G) formed in the green sub-pixel (G sub-pixel).

[0112] Similar to the hole transport layer HTL2-2(R) of type 2-2, the red emitting layer EML(R) can be formed using a mask deposition process. In this case, the red emitting layer EML(R) can be formed not only in the red sub-pixel (R sub-pixel) but also extend to the green sub-pixel (G sub-pixel) adjacent to the red sub-pixel (R sub-pixel). For example, the red emitting layer EML(R) can extend to the region overlapping with the green emitting region G-EA of the green sub-pixel (G sub-pixel).

[0113] The thickness of the extension of the red emissive layer EML(R) extending into the green subpixel (G subpixel) can be thinner than the thickness of the red emissive layer EML(R) formed in the red subpixel (R subpixel).

[0114] In the following implementation, when the red light-emitting layer disposed in one sub-pixel extends to another adjacent sub-pixel, the thickness of the extended portion of the red light-emitting layer extending to the other adjacent sub-pixel may be thinner than the thickness of the red light-emitting layer disposed in one sub-pixel.

[0115] According to an embodiment of the present invention, the second-first hole transport layer HTL2-1(G), the green emitting layer EML(G), the second-second hole transport layer HTL2-2(R), and the red emitting layer EML(R) can be formed sequentially by a deposition process. Therefore, the green emitting layer EML(G) can be disposed on the second-first hole transport layer HTL2-1(G), the second-second hole transport layer HTL2-2(R) can be disposed on the green emitting layer EML(G), and the red emitting layer EML(R) can be disposed on the second-second hole transport layer HTL2-2(R).

[0116] The electron transport layer (ETL) is disposed on the light-emitting layers (EML(R) and EML(G)) and is formed as a continuous layer without being broken in the red sub-pixel (R sub-pixel) and the green sub-pixel (G sub-pixel).

[0117] The electron injection layer (EIL) is disposed on the electron transport layer (ETL) and is formed as a continuous layer without being broken in the red sub-pixels (R sub-pixels) and green sub-pixels (G sub-pixels).

[0118] The second electrode 600 is disposed on the light-emitting part 500. The second electrode 600 is formed as a continuous electrode without being interrupted in the red sub-pixel (R sub-pixel) and the green sub-pixel (G sub-pixel).

[0119] An electroluminescent display device according to an embodiment of the present invention may be configured as a top-emitting type, and therefore the second electrode 600 may include a transparent electrode or a semi-transparent electrode.

[0120] Although not shown, an encapsulation layer may be additionally disposed on the second electrode 600.

[0121] According to an embodiment of the present invention, a hole transport layer HTL2-1(G) is deposited, followed by a green luminescent layer EML(G), then a hole transport layer HTL2-2(R) is deposited, followed by a red luminescent layer EML(R).

[0122] Therefore, in a portion of the green sub-pixel (G sub-pixel), a portion of the red sub-pixel (R sub-pixel), and the boundary region between the green sub-pixel (G sub-pixel) and the red sub-pixel (R sub-pixel), the green emitting layer EML (G), the second-second hole transport layer HTL2-2 (R), and the red emitting layer EML (R) can be sequentially disposed on the second-first hole transport layer HTL2-1 (G).

[0123] In other words, in a portion of the green sub-pixel (G sub-pixel), a portion of the red sub-pixel (R sub-pixel), and in the boundary region between the green sub-pixel (G sub-pixel) and the red sub-pixel (R sub-pixel), the hole transport layer HTL2-2(R) can be set between the green emissive layer EML(G) and the red emissive layer EML(R).

[0124] Therefore, in a portion of the red sub-pixel (R sub-pixel), for example in the red emitting region R-EA, a green emitting layer EML(G) can be positioned below the red emitting layer EML(R), with a second-second hole transport layer HTL2-2(R) interposed therebetween. Thus, the second-second hole transport layer HTL2-2(R) acts as a blocking layer to prevent electrons from moving to the green emitting layer EML(G). Therefore, although the green emitting layer EML(G) extends within the red emitting region R-EA, the movement of electrons towards the green emitting layer EML(G) is blocked by the second-second hole transport layer HTL2-2(R), thus preventing light emission within the green emitting layer EML(G). Consequently, the color of the red light emitted from the red emitting layer EML(R) of the red sub-pixel (R sub-pixel) remains unchanged.

[0125] Furthermore, in the green emitting region G-EA, the red emitting layer EML(R) can be disposed on the green emitting layer EML(G), with the second-second hole transport layer HTL2-2(R) interposed between them. Therefore, there is no blocking layer preventing electrons from moving to the red emitting layer EML(R), and the red emitting layer EML(R) can emit light in the green emitting region G-EA. However, as described above... Figure 2A and Figure 2B As shown, since the OC spectrum of the green wavelength band does not shift towards longer wavelengths, light emitted from the red emitting layer EML(R) will not be emitted into the green emitting region G-EA through destructive interference. As a result, the color of the green light emitted from the green emitting layer EML(G) of the green sub-pixel (G sub-pixel) remains unchanged.

[0126] Figure 6 This is an energy band diagram of the light-emitting portion of the red sub-pixel according to an embodiment of the present invention.

[0127] like Figure 6 As shown, in the case of red sub-pixel (R sub-pixel), the second-first hole transport layer HTL2-1(G), the green light-emitting layer EML(G), the second-second hole transport layer HTL2-2(R), the red light-emitting layer EML(R), and the electron transport layer ETL can be formed sequentially.

[0128] In this case, holes can be smoothly moved from the 2-1 hole transport layer HTL2-1(G) to the green light-emitting layer EML(G), the 2-2 hole transport layer HTL2-2(R), and the red light-emitting layer EML(R), so that holes can be smoothly supplied to the green light-emitting layer EML(G) and the red light-emitting layer EML(R).

[0129] However, electrons can move smoothly from the electron transport layer ETL to the red emitting layer EML(R), but the LUMO (lowest unoccupied molecular orbital) level of the hole transport layer HTL2-2(R) is so high that electrons cannot move to the hole transport layer HTL2-2(R). Therefore, electrons are successfully supplied to the red emitting layer EML(R), but electrons are not successfully supplied to the green emitting layer EML(G).

[0130] As a result, light emission occurs in the red emitting layer EML(R) through the combination of holes and electrons, but no light emission occurs in the green emitting layer EML(G) because the combination of holes and electrons is impossible.

[0131] As described above, according to an embodiment of the present invention, since the second-2 hole transport layer HTL2-2(R) in the red sub-pixel (R sub-pixel) can be used as a blocking layer to block electrons from moving to the green emitting layer EML(G), even if the green emitting layer EML(G) is disposed in the red sub-pixel (R sub-pixel), no light emission will occur in the green emitting layer EML(G), and the color of the red light emitted from the red emitting layer EML(R) will not change.

[0132] Figure 7 This is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, showing red sub-pixels and green sub-pixels that are adjacent to each other. Figure 7 Corresponding to another embodiment Figure 4 The cross section of line AA.

[0133] Figure 7 Based on the above Figure 5 The difference between this electroluminescent display device and the previous one lies in the altered construction of the second hole transport layers HTL2-2(R) and HTL2-1(G). Therefore, the different configurations will be described below.

[0134] According to the above Figure 5 The second-first hole transport layer HTL2-1(G) is formed with the same pattern as the green light-emitting layer EML(G), and the second-second hole transport layer HTL2-2(R) is formed with the same pattern as the red light-emitting layer EML(R).

[0135] In other words, according to the above Figure 5The hole transport layer HTL2-1(G) and the green emitting layer EML(G) extend from the green sub-pixel (G sub-pixel) to the red emitting area R-EA of the adjacent red sub-pixel (R sub-pixel), and the hole transport layer HTL2-2(R) and the red emitting layer EML(R) extend from the red sub-pixel (R sub-pixel) to the green emitting area G-EA of the adjacent green sub-pixel (G sub-pixel).

[0136] Therefore, according to the above Figure 5 In each of the red sub-pixels (R sub-pixels) and the green sub-pixels (G sub-pixels), the green light-emitting layer EML (G) and the red light-emitting layer EML (R) do not contact each other and are spaced apart from each other by a second-second hole transport layer HTL2-2 (R) inserted therebetween, for example, vertically separated.

[0137] Furthermore, according to the above Figure 5 In each of the red sub-pixels (R sub-pixels) and green sub-pixels (G sub-pixels), the second-first hole transport layer HTL2-1(G) and the second-second hole transport layer HTL2-2(R) are separated vertically by a green light-emitting layer EML(G) interposed therebetween. However, in the red sub-pixels (R sub-pixels), the second-first hole transport layer HTL2-1(G) is in contact with the second-second hole transport layer HTL2-2(R). For example, one end of the second-first hole transport layer HTL2-1(G) is in contact with the second-second hole transport layer HTL2-2(R).

[0138] On the other hand, according to Figure 7 The second-first hole transport layer HTL2-1(G) is formed with a pattern different from that of the green light-emitting layer EML(G), and the second-second hole transport layer HTL2-2(R) is formed with a pattern different from that of the red light-emitting layer EML(R).

[0139] Specifically, the green emitting layer EML(G) extends from the green sub-pixel (G sub-pixel) to the red emitting region R-EA of the adjacent red sub-pixel (R sub-pixel), but the hole transport layer HTL2-1(G) is located in the green sub-pixel (G sub-pixel) and does not extend to the adjacent red sub-pixel (R sub-pixel), for example, the red emitting region R-EA.

[0140] Furthermore, the red emitting layer EML(R) extends from the red sub-pixel (R sub-pixel) to the green emitting region G-EA of the adjacent green sub-pixel (G sub-pixel), but the hole transport layer HTL2-2(R) is located in the red sub-pixel (R sub-pixel) and does not extend to the adjacent green sub-pixel (G sub-pixel), for example, the green emitting region G-EA.

[0141] Therefore, in the red sub-pixel (R sub-pixel), the green emitting layer EML(G) and the red emitting layer EML(R) do not contact each other, but are separated vertically by the hole transport layer HTL2-2(R) inserted between them. However, in the green sub-pixel (G sub-pixel), the red emitting layer EML(R) can contact the green emitting layer EML(G). For example, the lower surface of the red emitting layer EML(R) contacts the upper surface of the green emitting layer EML(G).

[0142] Furthermore, in the boundary region between the red sub-pixel (R sub-pixel) and the green sub-pixel (G sub-pixel), the 2-1 hole transport layer HTL2-1(G) and the 2-2 hole transport layer HTL2-2(R) are separated vertically by a green light-emitting layer EML(G) interposed therebetween, and the 2-1 hole transport layer HTL2-1(G) and the 2-2 hole transport layer HTL2-2(R) do not contact each other throughout the entire region of the red sub-pixel (R sub-pixel) and the green sub-pixel (G sub-pixel).

[0143] According to such Figure 7 In another embodiment of the invention shown, a green light-emitting layer EML(G) may be disposed below the red light-emitting layer EML(R) in the red light-emitting region R-EA of the red sub-pixel (R sub-pixel), with a second-second hole transport layer HTL2-2(R) interposed therebetween. Therefore, the second-second hole transport layer HTL2-2(R) can act as a blocking layer to prevent electrons from moving to the green light-emitting layer EML(G). Thus, although the green light-emitting layer EML(G) extends within the red light-emitting region R-EA, the movement of electrons towards the green light-emitting layer EML(G) can be blocked by the second-second hole transport layer HTL2-2(R), and therefore no light emission occurs in the green light-emitting layer EML(G). As a result, the color of the red light emitted from the red light-emitting layer EML(R) of the red sub-pixel (R sub-pixel) remains unchanged.

[0144] Furthermore, in the green emitting region G-EA, the red emitting layer EML(R) is in contact with and disposed on the green emitting layer EML(G). Therefore, there is no blocking layer that prevents electrons from moving to the red emitting layer EML(R), and the red emitting layer EML(R) can emit light in the green emitting region G-EA. However, as described above... Figure 2Aand Figure 2B As described, since the OC spectrum of the green wavelength band does not shift towards longer wavelengths, light emitted from the red emitting layer EML(R) will not be emitted into the green emitting region G-EA through destructive interference. As a result, the color of the green light emitted from the green emitting layer EML(G) of the green sub-pixel (G sub-pixel) remains unchanged.

[0145] Figure 8 This is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, showing green and blue sub-pixels adjacent to each other. Figure 8 Corresponding to the implementation method Figure 4 The cross section of line BB.

[0146] like Figure 8 As shown, the electroluminescent display device according to an embodiment of the present invention includes a substrate 100, a circuit element layer 200, a passivation layer 310, a planarization layer 320, a first electrode 400, a dam portion 450, a light-emitting portion 500, and a second electrode 600.

[0147] Due to the structure of the substrate 100, circuit element layer 200, passivation layer 310, planarization layer 320, first electrode 400, embankment 450, and second electrode 600, Figure 5 Since their constructions are the same, their repeated descriptions will be omitted.

[0148] The light-emitting part 500 includes a hole injection layer HIL, a first hole transport layer HTL1, a second-first hole transport layer HTL2-1(G), light-emitting layers EML(G) and EML(B), an electron transport layer ETL and an electron injection layer EIL.

[0149] The hole injection layer HIL is formed as a continuous layer, without being broken in the green subpixel (G subpixel) and blue subpixel (B subpixel).

[0150] The first hole transport layer HTL1 is disposed on the hole injection layer HIL and is formed as a continuous layer without being broken in the green sub-pixel (G sub-pixel) and blue sub-pixel (B sub-pixel).

[0151] A second-first hole transport layer HTL2-1(G) is disposed on the first hole transport layer HTL1. The second-first hole transport layer HTL2-1(G) may be formed of the same material as the first hole transport layer HTL1, but may also be formed of a different material. Although not shown, another hole transport layer may be disposed between the first hole transport layer HTL1 and the red emitting layer of the red sub-pixel, for example, Figure 5 or Figure 7 The second hole transport layer (HTL2-2(R)) in the model.

[0152] The hole transport layer HTL2-1(G) is set in the green sub-pixel (G sub-pixel) and microcavity effect is obtained in the green sub-pixel (G sub-pixel).

[0153] In the blue sub-pixel (B sub-pixel), a microcavity effect can be obtained through the first hole transport layer HTL1, and a separate second hole transport layer can be formed on the first hole transport layer HTL1.

[0154] The second-first hole transport layer HTL2-1(G) can be formed by a deposition process using a mask. In this case, the second-first hole transport layer HTL2-1(G) can be formed not only in the green sub-pixel (G sub-pixel) but also extend to the blue sub-pixel (B sub-pixel) adjacent to the green sub-pixel (G sub-pixel). For example, the second-first hole transport layer HTL2-1(G) can extend to the region overlapping with the blue emitting region B-EA of the blue sub-pixel (B sub-pixel).

[0155] The emissive layers EML(G) and EML(B) include a green emissive layer EML(G) disposed in the green sub-pixel (G sub-pixel) and a blue emissive layer EML(B) disposed in the blue sub-pixel (B sub-pixel).

[0156] The green emitting layer EML(G) can be formed using a mask deposition process. In this case, the green emitting layer EML(G) can be formed not only in the green sub-pixel (G sub-pixel) but also extend to the blue sub-pixel (B sub-pixel) adjacent to the green sub-pixel (G sub-pixel). For example, the green emitting layer EML(G) can extend to the region where it overlaps with the blue emitting area B-EA of the blue sub-pixel (B sub-pixel).

[0157] The blue emitting layer EML(B) can be formed using a mask deposition process. In this case, the blue emitting layer EML(B) can be formed not only in the blue sub-pixel (B sub-pixel) but also extend to the green sub-pixel (G sub-pixel) adjacent to the blue sub-pixel (B sub-pixel). For example, the blue emitting layer EML(B) can extend to the region where it overlaps with the green emitting area G-EA of the green sub-pixel (G sub-pixel).

[0158] According to an embodiment of the present invention, the blue emitting layer EML(B) can be deposited and formed before the green emitting layer EML(G), and therefore, the blue emitting layer EML(B) can be disposed below the green emitting layer EML(G).

[0159] According to an embodiment of the present invention, the first hole transport layer HTL1, the blue emitting layer EML(B), the second-first hole transport layer HTL2-1(G), and the green emitting layer EML(G) can be formed sequentially by a deposition process. Therefore, the blue emitting layer EML(B) can be disposed on the first hole transport layer HTL1, the second-first hole transport layer HTL2-1(G) can be disposed on the blue emitting layer EML(B), and the green emitting layer EML(G) can be disposed on the second-first hole transport layer HTL2-1(G).

[0160] The electron transport layer (ETL) is disposed on the light-emitting layers (EML(G) and EML(B)) and is formed as a continuous layer without being broken in the green sub-pixel (G sub-pixel) and the blue sub-pixel (B sub-pixel).

[0161] The electron injection layer (EIL) is disposed on the electron transport layer (ETL) and is formed as a continuous layer without being broken in the green sub-pixels (G sub-pixels) and blue sub-pixels (B sub-pixels).

[0162] According to an embodiment of the present invention, a first hole transport layer HTL1 is deposited, followed by a blue emitting layer EML(B), then a second-first hole transport layer HTL2-1(G), and then a green emitting layer EML(G).

[0163] Therefore, in a portion of the green sub-pixel (G sub-pixel), a portion of the blue sub-pixel (B sub-pixel), and the boundary region between the green sub-pixel (G sub-pixel) and the blue sub-pixel (B sub-pixel), the blue emitting layer EML (B), the second-first hole transport layer HTL2-1 (G), and the green emitting layer EML (G) can be sequentially disposed on the first hole transport layer HTL1.

[0164] In other words, in a portion of the green sub-pixel (G sub-pixel), a portion of the blue sub-pixel (B sub-pixel), and the boundary region between the green sub-pixel (G sub-pixel) and the blue sub-pixel (B sub-pixel), the second-first hole transport layer HTL2-1(G) can be disposed between the green emitting layer EML(G) and the blue emitting layer EML(B). The blue emitting layer EML(B) and the green emitting layer EML(G) do not need to contact each other in the blue sub-pixel (B sub-pixel) and the green sub-pixel (G sub-pixel), but are separated from each other by the second-first hole transport layer HTL2-1(G) inserted between them.

[0165] Therefore, in a certain region of the green sub-pixel (G sub-pixel), for example in the green emitting region G-EA, a blue emitting layer EML(B) can be disposed below the green emitting layer EML(G), with a second-first hole transport layer HTL2-1(G) interposed therebetween. Thus, the second-first hole transport layer HTL2-1(G) can act as a blocking layer to prevent electrons from moving to the blue emitting layer EML(B). Therefore, although the blue emitting layer EML(B) extends within the green emitting region G-EA, the movement of electrons towards the blue emitting layer EML(B) can be blocked by the second-first hole transport layer HTL2-1(G), and thus no light emission occurs in the blue emitting layer EML(B). As a result, the color of the green light emitted from the green emitting layer EML(G) of the green sub-pixel (G sub-pixel) remains unchanged.

[0166] Furthermore, in the blue emitting region B-EA, the green emitting layer EML(G) can be disposed on the blue emitting layer EML(B), with a second-first hole transport layer HTL2-1(G) interposed between them. Therefore, there is no blocking layer preventing electrons from moving to the green emitting layer EML(G), and the green emitting layer EML(G) can emit light in the blue emitting region B-EA. However, as described above... Figure 3A and Figure 3B As shown, since the OC spectrum of the blue wavelength band does not overlap with the PL spectrum of the green wavelength band in the green emitting layer EML(G), light emitted from the green emitting layer EML(G) will not be emitted into the blue emitting region B-EA through destructive interference. As a result, the color of the blue light emitted from the blue emitting layer EML(B) of the blue sub-pixel (B sub-pixel) remains unchanged.

[0167] Figure 9 This is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, showing green sub-pixels and blue sub-pixels that are adjacent to each other. Figure 9 Corresponding to another embodiment Figure 4 The cross section of line BB.

[0168] Figure 9 Based on the above Figure 8 The difference between this electroluminescent display device and the previous one lies in the alteration of the structure of the 2-1 hole transport layer HTL2-1(G). Therefore, the different structure will be described below.

[0169] Based on the above description Figure 8 The second-first hole transport layer HTL2-1(G) is formed with the same pattern as the green light-emitting layer EML(G).

[0170] In other words, according to the above Figure 8The hole transport layer HTL2-1(G) and the green light-emitting layer EML(G) extend from the green sub-pixel (G sub-pixel) to the blue light-emitting region B-EA of the blue sub-pixel (B sub-pixel) adjacent to the green sub-pixel (G sub-pixel).

[0171] Therefore, according to the above Figure 8 In each of the green sub-pixels (G sub-pixels) and the blue sub-pixels (B sub-pixels), the green light-emitting layer EML (G) and the blue light-emitting layer EML (B) do not contact each other and are separated vertically by the second-first hole transport layer HTL2-1 (G) interposed therebetween.

[0172] On the other hand, according to Figure 9 The second-first hole transport layer HTL2-1(G) is formed with a pattern different from that of the green light-emitting layer EML(G).

[0173] Specifically, the green emitting layer EML(G) extends from the green sub-pixel (G sub-pixel) to the blue emitting region B-EA of the adjacent blue sub-pixel (B sub-pixel), but the hole transport layer HTL2-1(G) is formed in the green sub-pixel (G sub-pixel) and does not extend to the adjacent blue sub-pixel (B sub-pixel), for example, the blue emitting region B-EA.

[0174] Therefore, in the green sub-pixel (G sub-pixel), the green light-emitting layer EML (G) and the blue light-emitting layer EML (B) do not contact each other and are separated vertically by the hole transport layer HTL2-1 (R) inserted between them. However, in the blue sub-pixel (B sub-pixel), the lower surface of the green light-emitting layer EML (G) contacts the upper surface of the blue light-emitting layer EML (B).

[0175] According to such Figure 9 In another embodiment of the invention shown, in the green emitting region G-EA of the green sub-pixel (G sub-pixel), a blue emitting layer EML(B) can be disposed below the green emitting layer EML(G) and not in contact with it, with a second-first hole transport layer HTL2-1(G) interposed therebetween. Therefore, the second-first hole transport layer HTL2-1(G) can act as a blocking layer to prevent electrons from moving to the blue emitting layer EML(B). Thus, although the blue emitting layer EML(B) extends within the green emitting region G-EA, the movement of electrons towards the blue emitting layer EML(B) can be blocked by the second-first hole transport layer HTL2-1(G), and therefore no light emission occurs in the blue emitting layer EML(B). As a result, the color of the green light emitted from the green emitting layer EML(G) of the green sub-pixel (G sub-pixel) remains unchanged.

[0176] Furthermore, in the blue emitting region B-EA, the green emitting layer EML(G) is in contact with and disposed on the blue emitting layer EML(B). Therefore, there is no blocking layer that prevents electrons from moving to the green emitting layer EML(G), and the green emitting layer EML(G) can emit light in the blue emitting region B-EA. However, as described above... Figure 3A and Figure 3B As shown, since the OC spectrum of the blue wavelength band does not overlap with the PL spectrum of the green wavelength band in the green emitting layer EML(G), light emitted from the green emitting layer EML(G) will not be emitted into the blue emitting region B-EA through destructive interference. As a result, the color of the blue light emitted from the blue emitting layer EML(B) of the blue sub-pixel (B sub-pixel) remains unchanged.

[0177] Figure 10 This is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, showing red sub-pixels and blue sub-pixels that are adjacent to each other. Figure 10 Corresponding to the implementation method Figure 4 The cross section of line CC.

[0178] like Figure 10 As shown, the electroluminescent display device according to an embodiment of the present invention includes a substrate 100, a circuit element layer 200, a passivation layer 310, a planarization layer 320, a first electrode 400, a dam portion 450, a light-emitting portion 500, and a second electrode 600.

[0179] Due to the structure of the substrate 100, circuit element layer 200, passivation layer 310, planarization layer 320, first electrode 400, embankment 450, and second electrode 600, Figure 5 Since their constructions are the same, their repeated descriptions will be omitted.

[0180] The light-emitting unit 500 includes a hole injection layer HIL, a first hole transport layer HTL1, a second-second hole transport layer HTL2-2(R), light-emitting layers EML(R) and EML(B), an electron transport layer ETL, and an electron injection layer EIL.

[0181] The hole injection layer HIL is formed as a continuous layer, without being broken in the red subpixel (R subpixel or first subpixel) and blue subpixel (B subpixel or second subpixel).

[0182] The first hole transport layer HTL1 is disposed on the hole injection layer HIL and is formed as a continuous layer without being broken in the red sub-pixel (R sub-pixel) and blue sub-pixel (B sub-pixel).

[0183] The second-second hole transport layer HTL2-2(R) is disposed on the first hole transport layer HTL1. The second-second hole transport layer HTL2-2(R) may be formed of the same material as the first hole transport layer HTL1, but may also be formed of different materials.

[0184] The hole transport layer HTL2-1(R) is set in the red sub-pixel (R sub-pixel) and microcavity effect is obtained in the red sub-pixel (R sub-pixel).

[0185] In the blue sub-pixel (B sub-pixel), a microcavity effect can be obtained through the first hole transport layer HTL1, and a separate second hole transport layer can be formed on the first hole transport layer HTL1.

[0186] The second-second hole transport layer HTL2-2(R) can be formed using a mask deposition process. In this case, the second-second hole transport layer HTL2-2(R) can be formed not only in the red sub-pixel (R sub-pixel) but also extend to the blue sub-pixel (B sub-pixel) adjacent to the red sub-pixel (R sub-pixel). For example, the second-second hole transport layer HTL2-2(R) can extend to the region overlapping with the blue emitting region B-EA of the blue sub-pixel (B sub-pixel).

[0187] The emissive layers EML(R) and EML(B) include a red emissive layer EML(R) disposed in the red sub-pixel (R sub-pixel) and a blue emissive layer EML(B) disposed in the blue sub-pixel (B sub-pixel).

[0188] The red emitting layer EML(R) can be formed using a mask deposition process. In this case, the red emitting layer EML(R) can be formed not only in the red sub-pixel (R sub-pixel) but also extend to the blue sub-pixel (B sub-pixel) adjacent to the red sub-pixel (R sub-pixel). For example, the red emitting layer EML(R) can extend to the region where it overlaps with the blue emitting area B-EA of the blue sub-pixel (B sub-pixel).

[0189] The blue emitting layer EML(B) can be formed using a mask deposition process. In this case, the blue emitting layer EML(B) can be formed not only in the blue sub-pixel (B sub-pixel) but also extend to the red sub-pixel (R sub-pixel) adjacent to the blue sub-pixel (B sub-pixel). For example, the blue emitting layer EML(B) can extend to the region where it overlaps with the red emitting area R-EA of the red sub-pixel (R sub-pixel).

[0190] According to an embodiment of the present invention, the blue emitting layer EML(B) can be deposited and formed before the red emitting layer EML(R), and therefore, the blue emitting layer EML(B) can be disposed below the red emitting layer EML(R).

[0191] According to an embodiment of the present invention, the first hole transport layer HTL1, the blue emitting layer EML(B), the second-second hole transport layer HTL2-2(R), and the red emitting layer EML(R) can be formed sequentially by a deposition process. Therefore, the blue emitting layer EML(B) can be disposed on the first hole transport layer HTL1, the second-second hole transport layer HTL2-2(R) can be disposed on the blue emitting layer EML(B), and the red emitting layer EML(R) can be disposed on the second-second hole transport layer HTL2-2(R).

[0192] The electron transport layer (ETL) is disposed on the light-emitting layers (EML(R) and EML(B)) and is formed as a continuous layer without being broken in the red sub-pixel (R sub-pixel) and the blue sub-pixel (B sub-pixel).

[0193] The electron injection layer (EIL) is disposed on the electron transport layer (ETL) and is formed as a continuous layer without being broken in the red sub-pixel (R sub-pixel) and blue sub-pixel (B sub-pixel).

[0194] According to an embodiment of the present invention, a first hole transport layer HTL1 is deposited, followed by a blue emitting layer EML(B), then a second-second hole transport layer HTL2-2(R), and finally a red emitting layer EML(R).

[0195] Therefore, in a portion of the red sub-pixel (R sub-pixel), a portion of the blue sub-pixel (B sub-pixel), and in the boundary region between the red sub-pixel (R sub-pixel) and the blue sub-pixel (B sub-pixel), the blue emitting layer EML (B), the second-second hole transport layer HTL2-2 (R), and the red emitting layer EML (R) can be sequentially disposed on the first hole transport layer HTL1.

[0196] In other words, in a portion of the red sub-pixel (R sub-pixel), a portion of the blue sub-pixel (B sub-pixel), and in the boundary region between the red sub-pixel (R sub-pixel) and the blue sub-pixel (B sub-pixel), the hole transport layer HTL2-2(R) can be set between the red emissive layer EML(R) and the blue emissive layer EML(B).

[0197] Therefore, in a portion of the red sub-pixel (R sub-pixel), for example in the red emitting region R-EA, a blue emitting layer EML(B) can be positioned below the red emitting layer EML(R), with a second-second hole transport layer HTL2-2(R) interposed therebetween. Thus, the second-second hole transport layer HTL2-2(R) acts as a barrier layer, preventing electrons from moving to the blue emitting layer EML(B). Therefore, although the blue emitting layer EML(B) extends within the red emitting region R-EA, electron movement towards the blue emitting layer EML(B) is blocked by the second-second hole transport layer HTL2-2(R), thus preventing light emission within the blue emitting layer EML(B). Consequently, the color of the red light emitted from the red emitting layer EML(R) of the red sub-pixel (R sub-pixel) remains unchanged.

[0198] Individually, even if electrons move to the blue emitting layer EML(B), the blue emitting layer EML(B) can still emit light in the red emitting region R-EA. However, as described above... Figure 1A and 1B As shown, since the OC spectrum of the red wavelength band does not overlap with the PL spectrum of the blue wavelength band in the blue emissive layer EML(B), the light emitted from the blue emissive layer EML(B) undergoes destructive interference and is not emitted into the red emissive region R-EA. As a result, the color of the red light emitted from the red emissive layer EML(R) of the red sub-pixel (R sub-pixel) remains unchanged.

[0199] Furthermore, in the blue emitting region B-EA, the red emitting layer EML(R) can be disposed on the blue emitting layer EML(B), with a second-second hole transport layer HTL2-2(R) interposed between them. Therefore, there is no blocking layer preventing electrons from moving to the red emitting layer EML(R), and the red emitting layer EML(R) can emit light in the blue emitting region B-EA. However, as described above... Figure 3A and 3B As shown, since the OC spectrum of the blue wavelength band does not overlap with the PL spectrum of the red wavelength band in the red emitting layer EML(R), the light emitted from the red emitting layer EML(R) undergoes destructive interference and is not emitted into the blue emitting region B-EA. As a result, the color of the blue light emitted from the blue emitting layer EML(B) of the blue sub-pixel (B sub-pixel) remains unchanged.

[0200] Figure 11 This is a schematic cross-sectional view of an electroluminescent display device according to another embodiment of the present invention, showing red sub-pixels and blue sub-pixels that are adjacent to each other. Figure 11 Corresponding to another embodiment Figure 4 The cross section of line CC.

[0201] Figure 11 Based on the above Figure 10 The difference between this electroluminescent display device and the previous one lies in the altered structure of the hole transport layer HTL2-2(R). Therefore, the different structure will be described below.

[0202] Based on the above description Figure 10 The second-second hole transport layer HTL2-2(R) is formed with the same pattern as the red emitting layer EML(R).

[0203] In other words, according to the above Figure 10 The hole transport layer HTL2-2(R) and the red emitting layer EML(R) extend from the red subpixel (R subpixel) to the blue emitting region B-EA of the blue subpixel (B subpixel) adjacent to the red subpixel (R subpixel).

[0204] Therefore, according to the above Figure 10 In each of the red sub-pixels (R sub-pixels) and blue sub-pixels (B sub-pixels), the red light-emitting layer EML(R) and the blue light-emitting layer EML(B) do not contact each other and are separated vertically by a second-second hole transport layer HTL2-2(R) interposed therebetween.

[0205] On the other hand, according to Figure 11 The second-second hole transport layer HTL2-2(R) is formed with a pattern different from that of the red light-emitting layer EML(R).

[0206] Specifically, the red emitting layer EML(R) extends from the red sub-pixel (R sub-pixel) to the blue emitting region B-EA of the adjacent blue sub-pixel (B sub-pixel), but the hole transport layer HTL2-2(R) is formed in the red sub-pixel (R sub-pixel) and does not extend to the adjacent blue sub-pixel (B sub-pixel), for example, the blue emitting region B-EA.

[0207] Therefore, in the red sub-pixel (R sub-pixel), the red emitting layer EML(R) and the blue emitting layer EML(B) do not contact each other, but are separated by the hole transport layer HTL2-2(R) inserted between them. However, in the blue sub-pixel (B sub-pixel), the lower surface of the red emitting layer EML(R) contacts the upper surface of the blue emitting layer EML(B).

[0208] According to such Figure 11In another embodiment of the invention shown, in the red emitting region R-EA of the red sub-pixel (R sub-pixel), a blue emitting layer EML(B) can be disposed below the red emitting layer EML(R), with a second-second hole transport layer HTL2-2(R) interposed therebetween. Therefore, the second-second hole transport layer HTL2-2(R) can act as a blocking layer to prevent electrons from moving to the blue emitting layer EML(B). Thus, although the blue emitting layer EML(B) extends within the red emitting region R-EA, the movement of electrons towards the blue emitting layer EML(B) can be blocked by the second-second hole transport layer HTL2-2(R), and therefore no light emission occurs in the blue emitting layer EML(B). Therefore, the color of the red light emitted from the red emitting layer EML(R) of the red sub-pixel (R sub-pixel) remains unchanged.

[0209] Individually, even if electrons move to the blue emitting layer EML(B), the blue emitting layer EML(B) can still emit light in the red emitting region R-EA. However, as described above... Figure 1A and 1B As shown, since the OC spectrum of the red wavelength band does not overlap with the PL spectrum of the blue wavelength band in the blue emissive layer EML(B), the light emitted from the blue emissive layer EML(B) undergoes destructive interference and is not emitted into the red emissive region R-EA. As a result, the color of the red light emitted from the red emissive layer EML(R) of the red sub-pixel (R sub-pixel) remains unchanged.

[0210] Furthermore, in the blue emitting region B-EA, the red emitting layer EML(R) is in contact with and disposed on the blue emitting layer EML(B). Therefore, there is no blocking layer that prevents electrons from moving to the red emitting layer EML(R), and the red emitting layer EML(R) can emit light in the blue emitting region B-EA. However, as described above... Figure 3A and 3B As shown, since the OC spectrum of the blue wavelength band does not overlap with the PL spectrum of the red wavelength band in the red emitting layer EML(R), the light emitted from the red emitting layer EML(R) undergoes destructive interference and is not emitted into the blue emitting region B-EA. As a result, the color of the blue light emitted from the blue emitting layer EML(B) of the blue sub-pixel (B sub-pixel) remains unchanged.

[0211] Figure 12A It is based on the EL spectrum of the red sub-pixel of the comparative example. Figure 12B This is the EL spectrum of the red sub-pixel according to an embodiment of the present invention.

[0212] Figure 12B Involving Figure 5 The structure, Figure 12A Involving in Figure 5The structure removes the second-second hole transport layer HTL2-2(R) between the green emitting layer EML(G) and the red emitting layer EML(R) in the red sub-pixel so that the green emitting layer EML(G) and the red emitting layer EML(R) are in contact in the red sub-pixel.

[0213] like Figure 12A As shown, when there is no hole transport layer HTL2-2(R) between the green emitting layer EML(G) and the red emitting layer EML(R) in the red sub-pixel, the green emitting layer EML(G) and the red emitting layer EML(R) emit light together, and can emit light of a medium wavelength around 530nm. Therefore, red light of the desired EL spectrum will not be emitted in the red sub-pixel.

[0214] On the contrary, such as Figure 12B As shown, when a hole transport layer HTL2-2(R) exists between the green emitting layer EML(G) and the red emitting layer EML(R) in the red sub-pixel, the hole transport layer HTL2-2(R) blocks the movement of electrons to the green emitting layer EML(G), thus no light emission occurs in the green emitting layer EML(G). Therefore, red light of the desired EL spectrum can be emitted from the red sub-pixel based on the light emission of the red emitting layer EML(R).

[0215] It will be apparent to those skilled in the art that the present invention is not limited to the described embodiments and drawings, and that various substitutions, modifications, and variations can be made in the present invention without departing from its spirit or scope. Therefore, the scope of the present invention is defined by the appended claims, and all variations or modifications derived from the meaning, scope, and equivalent concepts of the claims are intended to fall within the scope of the present invention.

Claims

1. An electroluminescent display device, comprising: A substrate, the substrate comprising a first sub-pixel and a second sub-pixel; The first electrode in each of the first sub-pixel and the second sub-pixel on the substrate; The light-emitting portion on the first electrode; as well as The second electrode on the light-emitting part, The light-emitting portion includes a hole transport layer, a first light-emitting layer disposed in the first sub-pixel, a second light-emitting layer disposed in the second sub-pixel, and an electron transport layer. The second light-emitting layer extends to the first sub-pixel and is disposed below the first light-emitting layer. The hole transport layer is disposed between the second light-emitting layer and the first light-emitting layer in the first sub-pixel.

2. The electroluminescent display device as claimed in claim 1, wherein the second light-emitting layer extends into the light-emitting area of ​​the first sub-pixel. The hole transport layer is disposed between the second light-emitting layer and the first light-emitting layer in the light-emitting region of the first sub-pixel.

3. The electroluminescent display device according to claim 1, wherein the first light-emitting layer emits light with a longer wavelength than the second light-emitting layer.

4. The electroluminescent display device according to claim 1, wherein the hole transport layer comprises: The first hole transport layer in the first sub-pixel and the second sub-pixel; as well as A second hole transport layer is disposed on top of the first hole transport layer in the first sub-pixel. The second hole transport layer is disposed between the second light-emitting layer and the first light-emitting layer in the first sub-pixel.

5. The electroluminescent display device of claim 4, wherein the first light-emitting layer extends to the second sub-pixel.

6. The electroluminescent display device according to claim 4, wherein the first light-emitting layer and the second hole transport layer are formed with the same pattern.

7. The electroluminescent display device according to claim 6, wherein the first light-emitting layer and the second light-emitting layer do not contact each other in the first sub-pixel and the second sub-pixel, but are spaced apart from each other by a second hole transport layer inserted therebetween.

8. The electroluminescent display device according to claim 4, wherein the first light-emitting layer and the second hole transport layer are formed with different patterns.

9. The electroluminescent display device according to claim 8, wherein the first light-emitting layer and the second light-emitting layer are not in contact with each other in the first sub-pixel, but are spaced apart from each other by a second hole transport layer inserted therebetween, and the first light-emitting layer and the second light-emitting layer are in contact with each other in the second sub-pixel.

10. The electroluminescent display device according to claim 4, wherein the hole transport layer further comprises an additional hole transport layer disposed on the first hole transport layer in the second sub-pixel. The additional hole transport layer extends to the first sub-pixel and is disposed below the second light-emitting layer.

11. The electroluminescent display device according to claim 1, wherein the thickness of the extension portion of the second light-emitting layer extending to the first sub-pixel is thinner than the thickness of the second light-emitting layer disposed in the second sub-pixel.

12. The electroluminescent display device according to claim 5, wherein the thickness of the extension portion of the first light-emitting layer extending to the second sub-pixel is thinner than the thickness of the first light-emitting layer disposed in the first sub-pixel.

13. The electroluminescent display device according to claim 10, wherein the thickness of the second hole transport layer is greater than the thickness of the additional hole transport layer.

14. The electroluminescent display device of claim 10, wherein the additional hole transport layer is thinner in the first sub-pixel than in the second sub-pixel.

15. The electroluminescent display device according to claim 4, wherein the hole transport layer further comprises an additional hole transport layer disposed on the first hole transport layer in the second sub-pixel. The additional hole transport layer does not extend to the first sub-pixel.

16. The electroluminescent display device according to claim 4, wherein the second hole transport layer extends to the second sub-pixel, and the thickness of the extension portion of the second hole transport layer extending to the second sub-pixel is thinner than the thickness of the second hole transport layer disposed in the first sub-pixel.

17. An electroluminescent display device, comprising: Red sub-pixel, the red sub-pixel including a red emitting layer; Green sub-pixel, the green sub-pixel including a green emitting layer; Blue sub-pixel, the blue sub-pixel including a blue emitting layer; A first hole transport layer is disposed in the red sub-pixel, the green sub-pixel, and the blue sub-pixel, and is disposed below the red light-emitting layer, the green light-emitting layer, and the blue light-emitting layer; A second-1 hole transport layer is disposed between the first hole transport layer and the green light-emitting layer; as well as A second-2 hole transport layer is disposed between the first hole transport layer and the red emitting layer. The green light-emitting layer extends to the red sub-pixel and is disposed below the red light-emitting layer. The second-second hole transport layer is disposed between the green emitting layer and the red emitting layer.

18. The electroluminescent display device according to claim 17, wherein the green light-emitting layer extends to the red light-emitting area of ​​the red sub-pixel and is disposed below the red light-emitting layer. The second-2 hole transport layer is disposed in the red emitting region between the green emitting layer and the red emitting layer.

19. The electroluminescent display device according to claim 17, wherein the green light-emitting layer and the red light-emitting layer do not contact each other in the green sub-pixel and the red sub-pixel, but are spaced apart from each other by a second-2 hole transport layer inserted therebetween.

20. The electroluminescent display device according to claim 17, wherein the green light-emitting layer and the red light-emitting layer do not contact each other in the red sub-pixel, but are spaced apart from each other by a second-2 hole transport layer inserted therebetween, and the green light-emitting layer and the red light-emitting layer contact each other in the green sub-pixel.

21. The electroluminescent display device according to claim 17, wherein the second-1 hole transport layer is in contact with the second-2 hole transport layer in the red sub-pixel.

22. The electroluminescent display device according to claim 17, wherein the second-1 hole transport layer does not contact the second-2 hole transport layer in the red sub-pixel and the green sub-pixel.

23. An electroluminescent display device, comprising: Red sub-pixel, the red sub-pixel including a red emitting layer; Green sub-pixel, the green sub-pixel including a green emitting layer; Blue sub-pixel, the blue sub-pixel including a blue emitting layer; A first hole transport layer is disposed in the red sub-pixel, the green sub-pixel, and the blue sub-pixel, and is disposed below the red light-emitting layer, the green light-emitting layer, and the blue light-emitting layer; A second-1 hole transport layer is disposed between the first hole transport layer and the green light-emitting layer; as well as A second-2 hole transport layer is disposed between the first hole transport layer and the red emitting layer. The blue light-emitting layer extends into the green sub-pixel and is disposed below the green light-emitting layer. The second-first hole transport layer is disposed between the green light-emitting layer and the blue light-emitting layer.

24. The electroluminescent display device according to claim 23, wherein the blue light-emitting layer extends to the green light-emitting area of ​​the green sub-pixel and is disposed below the green light-emitting layer. The second-first hole transport layer is disposed in the green luminescent region between the blue luminescent layer and the green luminescent layer.

25. The electroluminescent display device according to claim 23, wherein the blue light-emitting layer and the green light-emitting layer do not contact each other in the blue sub-pixel and the green sub-pixel, but are spaced apart from each other by a second-first hole transport layer inserted therebetween.

26. The electroluminescent display device according to claim 23, wherein the blue light-emitting layer and the green light-emitting layer do not contact each other in the green sub-pixel, but are spaced apart from each other by a second-first hole transport layer inserted therebetween, and the blue light-emitting layer and the green light-emitting layer contact each other in the blue sub-pixel.

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