Electroluminescent display device

Abstract

An electroluminescent display device comprising: a plurality of sub-pixels (R, G, B) arranged in rows and columns on a substrate along a first direction and a second direction crossing the first direction, wherein the plurality of sub-pixels (R, G, B) comprise a plurality of first sub-pixels of a first color, a plurality of second sub-pixels of a second color, and a plurality of third sub-pixels of a third color, wherein the first color, the second color, and the third color are different from each other; and a light-emitting diode (De) arranged in each of the plurality of sub-pixels (R, G, B) and comprising a first electrode (162), a light-emitting layer (180), and a second electrode (190), wherein, among the plurality of sub-pixels (R, G, B), a sub-pixel of an n-th row and an m-th column has the same color as a sub-pixel of an (n+1)-th row and an (m-1)-th column, where n is a natural number and m is a natural number greater than 4.and wherein, among the plurality of subpixels (R, G, B), a subpixel of the nth row and a kth column and a subpixel of the nth row and a (k-2)th column are first subpixels having the first color, where k is a natural number less than or equal to m, wherein the plurality of subpixels (R, G, B) are arranged in pixel matrices of 4x4 subpixels, and in one of the pixel matrices, four first subpixels having the first color are connected to each other in a diagonal direction, three second subpixels having the second color are connected to each other in the diagonal direction, and three third subpixels having the third color are connected to each other in the diagonal direction.

Description

BACKGROUND OF THE INVENTIONFIELD OF DISCLOSUREThe present disclosure relates to an electroluminescent display device, and more particularly, to a large-format, high-resolution electroluminescent display device.Discussion of the Prior ArtAs a flat panel display device, an electroluminescent display device has large viewing angles as compared with a liquid crystal display device because it is self-luminous, and also has advantages in terms of a small thickness, a small weight, and a small power consumption because no backlight unit is required.In addition, the electroluminescent display device is driven by low DC voltages and has a fast response time. Moreover, the electroluminescent display device is robust against external impacts and is used in a wide temperature range because its components are solids. Moreover, the electroluminescent display device can be manufactured at low cost.The electroluminescent display device includes a plurality of pixels each having a red, a green, and a blue sub-pixel, and displays different color images by allowing red, green, and blue sub-pixels to selectively emit light.The red, green, and blue sub-pixels include red, green, and blue light emitting layers, respectively, and each light emitting layer is formed by a vacuum heat evaporation process in which a luminous material is selectively deposited using a fine metal mask. However, the evaporation process increases the manufacturing cost due to the manufacture of the mask and has a problem in application to a large-sized and high-resolution display device due to manufacturing variations, sagging, shadow effect of the mask, and the like.CN 1 03 345 887 A relates to a pixel array and a display apparatus comprising the pixel array. The pixel array includes a plurality of rows and a plurality of columns of sub-pixel base units. Each sub-pixel base unit is provided with first color sub-pixels, second color sub-pixels, and third color sub-pixels. A plurality of pixels are shown on each subpixel base unit. In the horizontal and vertical directions, the second color sub-pixels are not arranged side by side.SUMMARY OF THE INVENTIONAccordingly, the present disclosure is directed to an electroluminescent display device that substantially avoids one or more of the problems due to limitations and disadvantages of the prior art.An object of the present disclosure is to provide a large-format, high-resolution electroluminescent display device.The object is achieved by the features of the independent claims. Preferred embodiments are set out in the dependent claims.Additional features and advantages of the present disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present disclosure. The objects and other advantages of the present disclosure will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.To achieve these and other advantages and in accordance with the purpose of the present disclosure, as embodied and broadly described herein, an electroluminescent display device is provided that includes: a plurality of sub-pixels arranged in rows and columns on a substrate along a first direction and a second direction crossing the first direction, the plurality of sub-pixels including a plurality of first sub-pixels of a first color, a plurality of second sub-pixels of a second color, and a plurality of third sub-pixels of a third color, wherein the first color, the second color, and the third color are different from each other; and a light emitting diode disposed in each of the plurality of sub-pixels and comprising a first electrode, a light emitting layer, and a second electrode, wherein among the plurality of sub-pixels, a sub-pixel of an nth row and an mth column has the same color as a sub-pixel of an (n+1)th row and an (m-1)th column, wherein n is a natural number and m is a natural number greater than 4, and wherein among the plurality of sub-pixels, a sub-pixel of the nth row and a kth column and a sub-pixel of the nth row and a (k-2)th column are first sub-pixels having the first color, wherein k is a natural number less than or equal to m.The sub-pixels may be arranged in a matrix or grid configuration. The sub-pixels may be arranged in rows and columns extending along the first direction and the second direction, respectively. The first direction may correspond to the row direction, while the second direction may correspond to the column direction. The first direction and the second direction may extend perpendicular to each other. A diagonal direction may be defined as a direction crossing the first and second directions. Accordingly, a non-diagonal direction may be a direction that does not cross a direction of the first and second directions. A non-diagonal direction may extend parallel to a direction of the first and second directions.A sub-pixel of the nth row and a (k-1)th column may be a second sub-pixel having the second color. A sub-pixel of the nth row and a (k-3)th column may be a third sub-pixel having the third color.The first sub-pixels may be green sub-pixels. One of the second sub-pixel and the third sub-pixel may be a red sub-pixel. The other of the second sub-pixel and the third sub-pixel may be a blue sub-pixel.The light emitting layer in the subpixel of the n-th row and the m-th column and the light emitting layer in the subpixel of the (n+1)-th row and the (m-1)-th column may be connected to each other.The electroluminescent display device may further include a first bank covering an edge of the first electrode and disposed between adjacent sub-pixels of the same color. The electroluminescent display device may further include a second bank covering an edge of the first bank and disposed between adjacent sub-pixels of different colors.The first bank may extend along the first direction. The first bank may be disposed between adjacent sub-pixels extending along the second direction. The second bank may include a first opening and a second opening. The first opening may correspond to each of the plurality of sub-pixels. The second opening may correspond to a region between the subpixel of the nth row and the mth column and the subpixel of the (n+1)th row and the (m-1)th column.The second opening may connect the first opening corresponding to the subpixel of the nth row and the mth column to the first opening corresponding to the subpixel of the (n+1)th row and the (m-1)th column.The first opening may expose the first electrode. The second opening may expose the first opening.The light emitting layer may be disposed on the exposed first electrode and the exposed first opening.The first bank may have a hydrophilic property. The second bank may have a hydrophobic property.In another aspect, an electroluminescent display device includes a substrate on which a display region and a non-display region are defined, and a plurality of sub-pixels arranged in rows and columns in the display region and the non-display region, the plurality of sub-pixels including a plurality of first sub-pixels of a first color, a plurality of second sub-pixels of a second color, and a plurality of third sub-pixels of a third color, the first color, the second color, and the third color being different from each other, wherein among the plurality of sub-pixels in the display region and / or the non-display region, the sub-pixel of an nth row and an mth column has the same color as the sub-pixel of an (n+1)th row and an (m-1)th column, where n is a natural number and m is a natural number greater than 4, and wherein, among the plurality of sub-pixels in the display area and / or the non-display area, a sub-pixel of the nth row and a kth column and a sub-pixel of the nth row and a (k-2)th column are first sub-pixels having the first color, where k is a natural number less than or equal to m.The electroluminescent display device may further include a first bank between the sub-pixels having a light emitting layer of the same color in the display area.The electroluminescent display device may further include a second bank between the sub-pixels having light emitting layers of different colors in the display area and the non-display area.In another aspect, an electroluminescent display device includes a substrate in which a display region and a non-display region adjacent to the display region are provided, and a plurality of sub-pixels arranged in a grid configuration along a row direction and a column direction on the substrate, and including a connection region in which sub-pixels of the first color among the plurality of sub-pixels are connected to each other in a diagonal direction different from the row direction and the column direction, a first bank arranged on the substrate and having an opening extending in a non-diagonal direction and corresponding to a part of the plurality of sub-pixels, and a second bank covering a portion of the first bank and including a first opening corresponding to the opening of the first bank and a second opening corresponding to the connection region of the sub-pixels of the first color.The second portion of the second bank extending in the diagonal direction may overlap with the first bank.In another aspect, an electroluminescent display device includes a substrate; a plurality of sub-pixels arranged on the substrate along a first direction and a second direction; and a light emitting diode arranged on each of the plurality of sub-pixels and including a first electrode, a light emitting layer, and a second electrode, wherein a sub-pixel of an nth row (n is a natural number) and an mth column (m is a natural number greater than 4) has the same color as the sub-pixel of an (n+1)th row and an (m-1)th column, and wherein a sub-pixel of the nth row and a kth column (k is a natural number less than or equal to m) has the same color as the sub-pixel of the nth row and a (k-2)th column.The subpixel of the nth row and a kth column, the subpixel of the nth row and a (k-1)th column, and the subpixel of the nth row and a (k-3)th column may have different colors from each other.The subpixel of the nth row and the kth column and the subpixel of the nth row and the (k-2)th column may be green subpixels. One of the n-th row and (k-1)-th column sub-pixel and the n-th row and (k-3)-th column sub-pixel may be a red sub-pixel. The other of the n-th row and (k-1)-th column sub-pixel and the n-th row and (k-3)-th column sub-pixel may be a blue sub-pixel.The light emitting layer in the subpixel of the n-th row and the m-th column and the light emitting layer in the subpixel of the (n+1)-th row and the (m-1)-th column may be connected to each other.The electroluminescent display device may further include a first bank covering an edge of the first electrode and disposed between adjacent sub-pixels of the same color. The electroluminescent display device may further include a second bank covering an edge of the first bank and disposed between adjacent sub-pixels of different colors.The first bank may extend along the first direction. The first bank may be disposed between adjacent sub-pixels extending along the second direction. The second bank may include a first opening and a second opening. The first opening may correspond to each of the plurality of sub-pixels. The second opening may correspond to a region between the subpixel of the nth row and the mth column and the subpixel of the (n+1)th row and the (m-1)th column.The second opening may connect the first opening corresponding to the subpixel of the nth row and the mth column to the first opening corresponding to the subpixel of the (n+1)th row and the (m-1)th column.The first opening may expose the first electrode. The second opening may expose the first opening.The light emitting layer may be disposed on the exposed first electrode and the exposed first opening.The first bank may have a hydrophilic property. The second bank may have a hydrophobic property.In another aspect, an electroluminescent display device includes a substrate on which a display area and a non-display area are defined; and a plurality of sub-pixels arranged on the substrate along a first direction and a second direction, wherein the sub-pixel of an nth row (n is a natural number) and an mth column (m is a natural number greater than 4) has the same color as the sub-pixel of an (n+1)th row and an (m-1)th column, and wherein the sub-pixel of the nth row and a kth column (k is a natural number less than or equal to m) has the same color as the sub-pixel of the nth row and an (k-2)th column.In another aspect, an electroluminescent display device includes a plurality of sub-pixels arranged on a substrate along a first direction and a second direction crossing the first direction, and a light emitting diode arranged in each of the plurality of sub-pixels and including a first electrode, a light emitting layer, and a second electrode, wherein among the plurality of sub-pixels, the sub-pixel of an nth row and an mth column has the same color as the sub-pixel of an (n+1)th row and an (m-1)th column, where n is a natural number and m is a natural number greater than 4, and wherein among the plurality of sub-pixels, the sub-pixel of the nth row and a kth column has the same color as the sub-pixel of the nth row and an (k-2)th column, where k is a natural number less than or equal to m.In another aspect, an electroluminescent display device includes a substrate on which a display area and a non-display area are defined; and a plurality of sub-pixels arranged in the display area and the non-display area, wherein among the plurality of sub-pixels in the display area and / or the non-display area, the sub-pixel of an nth row and an mth column has the same color as the sub-pixel of an (n+1)th row and an (m-1)th column, where n is a natural number and m is a natural number greater than 4, and wherein among the plurality of sub-pixels in the display area and / or the non-display area, the sub-pixel of the nth row and a kth column has the same color as the sub-pixel of the nth row and a (k-2)th column, where k is a natural number less than or equal to m.The electroluminescent display device may further include a first bank between the sub-pixels having a light emitting layer of the same color in the display area.The electroluminescent display device may further include a second bank between the sub-pixels having light emitting layers of different colors in the display area and the non-display area.The second bank may include a first opening and a second opening. The first opening may correspond to each of the plurality of sub-pixels. The second opening may correspond to a portion between the subpixel of the nth row and the mth column and the subpixel of the (n+1)th row and the (m-1)th column.In another aspect, an electroluminescent display device includes a substrate in which a display area and a non-display area adjacent to the display area are provided; and a plurality of sub-pixels arranged in a grid configuration on the substrate and having a connection area in which sub-pixels of the first color among the plurality of sub-pixels are connected to each other in a diagonal direction; a first bank arranged on the substrate and having an opening extending in a non-diagonal direction and corresponding to a part of the plurality of sub-pixels; and a second bank covering a portion of the first bank and having a first opening corresponding to the opening of the first bank and a second opening corresponding to the connection area of the sub-pixels of the first color.The second bank may include a first portion disposed in a region between two adjacent sub-pixels extending in a row direction. The second bank may include a second portion extending from the first portion in a diagonal direction.The second portion of the second bank extending in the diagonal direction may overlap with the first bank.Each of two adjacent first color sub-pixels arranged in the diagonal direction may include a first electrode arranged on the substrate, a light emitting layer arranged on the first electrode, and a second electrode arranged on the light emitting layer. The first bank may overlap edges of the first electrodes of the two adjacent first color sub-pixels.The second bank may overlap edges of the first electrodes of the two adjacent first color sub-pixels.The light emitting layers of the two adjacent first color sub-pixels may be disposed over the first bank.The second electrode may be disposed over the first and second banks.The first bank may have a hydrophilic property. The second bank may have a hydrophobic property.The first and second banks may be disposed in the display area of the substrate. The second bank may be disposed in the non-display area of the substrate.The plurality of first color sub-pixels may be green sub-pixels.The plurality of sub-pixels may further include a plurality of second color sub-pixels arranged in the diagonal direction. The plurality of sub-pixels may further include a plurality of third color sub-pixels arranged in the diagonal direction. One of the second color sub-pixels or one of the third color sub-pixels may be arranged between two adjacent first color sub-pixels in a row or column direction.One of the second color or third color sub-pixels may be arranged only between two adjacent first color sub-pixels in the row direction. One of the second color or third color sub-pixels may be arranged only between two adjacent first color sub-pixels in the column direction.The plurality of first color sub-pixels may be arranged as dummy sub-pixels in the non-display region of the substrate.Each of the dummy sub-pixels disposed in the non-display region of the substrate may include a light emitting layer disposed on the substrate and an electrode disposed on the light emitting layer.It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the present disclosure as claimedBrief Description of the DrawingsThe accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain various principles of the disclosure: FIG. 1 is a schematic view of a pixel array of an electroluminescent display device according to a first embodiment, which does not illustrate the present invention. FIG. 2 is a schematic view of a pixel array of an electroluminescent display device according to a second embodiment of the present disclosure; FIG. 3 is a schematic cross-sectional view of an electroluminescent display device according to the second embodiment of the present disclosure; FIG. 4 is a schematic view of a pixel array of another example of an electroluminescent display device according to the second embodiment of the present disclosure; FIG. 5 is an equivalent circuit diagram of a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure; FIG. 6 is a timing chart schematically illustrating a plurality of signals applied to a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure, and shows a frame; FIG. 7 is a schematic plan view of a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure; FIG. 8 is a schematic cross-sectional view of a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure; and FIG. 9 is a schematic view of an electroluminescent display device according to a third embodiment of the present disclosure.Detailed Description of the EmbodimentsReference will now be made in detail to the embodiments of the present disclosure, examples of which are shown in the accompanying drawings.< Embodiment>FIG. 1 is a schematic view of a pixel array of an electroluminescent display device according to a first embodiment of the present disclosure. All components of the electroluminescent display device according to all embodiments of the present disclosure are operatively coupled and configured. For example, according to various embodiments of the present disclosure, components known in the art for displaying images over a display area, e.g., drivers, power lines, data lines, signal lines, etc., are provided to be operatively connected to a plurality of sub-pixels, which will be discussed in more detail below.In FIG. 1, the electroluminescent display device according to the first embodiment of the present disclosure includes red, green, and blue sub-pixels R, G, and B, and the red, green, and blue sub-pixels R, G, and B are arranged in a pentile shape.Specifically, in the electroluminescent display device according to the first embodiment of the present disclosure, the red and blue sub-pixels R and B are alternately arranged in the same column, and the green sub-pixels G are arranged in a column adjacent thereto. Here, the arrangement order of the red and blue sub-pixels R and B in one column is opposite to the arrangement order of the red and blue sub-pixels R and B in the next column.In general, red, green, and blue sub-pixels of a general electroluminescent display device are arranged in stripes so that the same-color sub-pixels are arranged in a column direction. However, the stripe arrangement has a problem that the opening ratio decreases as the resolution of the display device increases.On the other hand, in the pentile array, the number of red sub-pixels R and the number of blue sub-pixels B is half as large as the number of green sub-pixels G. As a result, the number of all sub-pixels in the pentile array is reduced to 2 / 3 as compared with the stripe array, so that the high aperture ratio can be ensured and the effective resolution for the number of sub-pixels can be increased by the rendering driving.Further, in the electroluminescent display device according to the first embodiment of the present disclosure, light emitting layers of the red, green, and blue sub-pixels R, G, and B are formed by a solution process. Therefore, manufacturing cost can be reduced because a fine metal mask is omitted, and a display device having a large size and high resolution can be implemented.When each light emitting layer is formed by the solution process, each solution is dropped into each of the plurality of sub-pixels, and different nozzles are used for the respective sub-pixels. However, due to a variation in the dropping amounts of the nozzles, a variation occurs in the thickness of a thin film formed in each sub-pixel. Accordingly, imbalance is generated along a scanning direction of the nozzles, and the image quality of the display device is lowered.An electroluminescent display device according to a second embodiment of the present disclosure for preventing the image quality from being lowered by preventing the imbalance will be described in detail with reference to FIG. 2.< Embodiment>FIG. 2 is a schematic view of a pixel array of an electroluminescent display device according to a second embodiment of the present disclosure, the pixel array being provided in a display area of the display device.In FIG. 2, the electroluminescent display device according to the second embodiment of the present disclosure includes red, green, and blue sub-pixels R, G, and B, and the same-color sub-pixels R, G, or B are arranged in a diagonal direction and are connected to each other among the same-color sub-pixels.Specifically, the red, green, and blue sub-pixels R, G, and B include red, green, and blue light emitting layers, respectively, and the red, green, and blue sub-pixels R, G, and B are arranged in a matrix form. In this regard, the green sub-pixels G are arranged in a diagonal direction so as to form a diamond lattice. The subpixel G in the nth row (n is a natural number) and the mth column (m is a natural number greater than 4), the subpixel G in the (n+1)th row and the (m-1)th column, the subpixel G in the (n+2)-th row and the (m-2)th column, and the subpixel G in the (n+3)-th row and the (m-3)th column have the same color, i.e., green, are arranged in a diagonal direction and are connected to each other at a connection region 150.At this time, in the n-th row and the (n+2)-th column, the sub-pixels G of the m-th column and the sub-pixels G of the (m-2)-th column have the same color green, and in the (n+1)-th row and the (n+3)-th row, the sub-pixels G of the (m-1)-th column and the sub-pixels G of the (m-3)-th column have the same color green. Moreover, all the green sub-pixels (e.g., G 1, G 2, G 3, and G 4) arranged in adjacent rows and diagonally to each other are connected to each other as illustrated, and the region where two adjacent green sub-pixels (e.g., between G 1 and G 2, or between G 2 and G 3, or between G 3 and G 4) are diagonally connected is referred to herein as the connection region 150. All green sub-pixels may include a plurality of the connection areas 150. As a result, in each row, the subpixel G of a k-th column (k is a natural number less than or equal to m) has the same color green as the subpixel G of the (k-2)-th column. For example, in each row of sub-pixels, preferably only one non-green sub-pixel (e.g., R or B sub-pixels and not two or more sub-pixels) exists between two adjacent green sub-pixels. In the example of FIG. 2, a blue sub-pixel B 1 exists between two adjacent green sub-pixels G 1 and G 5.In addition, the sub-pixel B in the (n-1)-th row and the m-th column, the sub-pixel B in the n-th row and the (m-1)-th column, the sub-pixel B in the (n+1)-th row and the (m-2)-th column, and the sub-pixel B in the (n+2)-th row and the (m-3)-th column have the same color, i.e., blue, are arranged in a diagonal direction and connected to each other. For example, in FIG. 2, the blue sub-pixels B 1, B 2, and B 3 are diagonally disposed and connected to each other, and thus have diagonally disposed connection areas similar to the connection areas 150. The subpixel R of the nth row and the (m+1)th column, the subpixel R in the (n+1)th row and the mth column, the subpixel R in the (n+2)th row and the (m-1)th column, and the subpixel R in the (n+3)th row and the (m-2)th column have the same color, i.e., red, and are arranged in the diagonal direction and connected to each other. For example, in FIG. 2, the red sub-pixels R 1, R 2, and R 3 are diagonally disposed and connected to each other, and thus have diagonally disposed connection areas similar to the connection areas 150.In the example of Figure 2, it can be seen that there is only a single R or B subpixel between two adjacent green subpixels in both the column and row directions, with all green subpixels forming a diamond grid. For example, there is only one blue sub-pixel B 1 between the two adjacent green sub-pixels G 1 and G 5 extending in a row direction, and there is only one blue sub-pixel B 2 between two adjacent green sub-pixels G 5 and G 3 extending in a column direction.The arrangement of the red, green and blue sub-pixels R, G and B is not limited to the illustrated configuration. When the rule according to the second embodiment is satisfied, for example, the red sub-pixel R or the blue sub-pixel B (instead of the green sub-pixel G as shown in FIG. 2 ) may be arranged in the n-th row and the m-th column. In this case, the sub-pixels of other colors would be used to meet the placement rules discussed above and below.Further, in the second embodiment of the present disclosure, the number of red sub-pixels R and the number of blue sub-pixels B are each half the number of green sub-pixels G, but are not limited thereto. The number of green and blue sub-pixels G and B may be half the number of red sub-pixels R, respectively, or the number of red and green sub-pixels R and G is half the number of blue sub-pixels B, respectively, as occasion demands.The pixel array according to the second embodiment of the present disclosure may be implemented using a bank structure.Specifically, a bank according to the second embodiment of the present disclosure includes a first bank 172 (shaded portion) and a second bank 174 (other shaded portion).The first bank 172 extends in a first direction (e.g., row direction) and is disposed between adjacent sub-pixels R, G, and B in a second direction (e.g., column direction) that is perpendicular to the first direction. For example, the first bank 172 may be considered strips extending in the row direction and having a plurality of openings 172a between the strips.The second bank 174 covers the entire pixel area shown in FIG. 2, but has a first opening 174 aand a second opening 174 b. Thus, the second bank 174 includes a first portion 174 cdisposed in an area between two adjacent sub-pixels extending in a row direction, wherein the first portion 174 cis disposed between two adjacent sub-pixels (e.g., B 3 and G 3, G 3 and R 2, etc.) (between the first openings 174 a). The second bank 174 further includes a second portion 174 dextending from the first portion 174 cin the diagonal direction, the second portion 174 dbeing diagonally disposed between two diagonally disposed adjacent second openings 174 b.For example, the second bank 174 is disposed between adjacent sub-pixels R, G, and B in the first direction and between adjacent sub-pixels R, G, and B in the second direction. The first opening 174 acorresponds to respective sub-pixels R, G, and B. For example, the first opening 174 ais located between the sub-pixels B 3 and G 3, between the sub-pixels G 2 and R 1, etc. The second opening 174 bis located between the adjacent sub-pixels R, G, and B having the same color, and connects the first openings 174 acorresponding to the adjacent sub-pixels R, G, and B having the same color. For example, the second opening 174 bis located between the same color sub-pixels G 2 and G 3, between the sub-pixels R 1 and R 2, etc. The second openings 174 bmay be arranged diagonally. Therefore, with respect to the same-color sub-pixels R, G, and B, for each color, the second bank 174 bhas the openings connected to each other along the diagonal direction crossing the first and second directions, and the red, green, and blue light emitting layers are respectively formed so that portions in the first and second openings 174 aand 174 bare connected to each other. The second bank 174 overlaps the first bank 172 in diagonally arranged areas between the diagonally arranged connection areas of the sub-pixels.A cross-sectional structure of the electroluminescent display device according to the second embodiment of the present disclosure will be described with reference to FIG. 3.FIG. 3 is a schematic cross-sectional view of an electroluminescent display device according to the second embodiment of the present disclosure, and shows a cross-section corresponding to the line III-III' of FIG. 2.In FIG. 3, a plating layer 160 is formed on a substrate 100 on which a plurality of sub-pixel regions P are defined, and a first electrode 162 is formed on each of the sub-pixel regions P on the plating layer 160.Further, one or more thin film transistors, capacitors, and insulating layers may be formed between the substrate 100 and the overcoat layer 160.A first bank 172 and a second bank 174 are formed on the first electrode 162 and cover edges of the first electrode 162. The first bank 172 may be formed of a material having a hydrophilic property, for example, an inorganic insulating material such as silicon oxide (SiO 2) or silicon nitride (SiN x). Alternatively, the first bank 172 may be formed of polyimide. In addition, the second bank 174 may be formed of an organic insulating material having a hydrophobic property. Alternatively, the second bank 174 may be formed of an organic insulating material having a hydrophilic property and may be subjected to a hydrophobic treatment.Here, the first bank 172 is formed between the same color subpixel areas P (e.g., between the green subpixels G 3 and G 2), and the second bank 174 is formed between different color subpixel areas P (e.g., between the blue and green subpixels B 3 and G 3). The first bank 172 has a hydrophilic property and the second bank 174 has a hydrophobic property. A thickness of the second bank 174 may be thicker than a thickness of the first bank 172. That is, the height of the second bank 174 may be greater than the height of the first bank 172.Meanwhile, the second bank 174 may include first and second openings 174 aand 174 b. The first opening 174 ais formed corresponding to each subpixel area P and exposes the first electrode 162. The second opening 174 bis formed between the same-color subpixel regions P adjacent to each other, i.e., between the green subpixels G (e.g., between the subpixels G 2 and G 3 and above the first bank 172 disposed therebetween), connects the first openings 174 acorresponding to the same-color subpixel regions P adjacent to each other, and exposes the first bank 172.A light emitting layer 180 is formed on the first electrode 162 exposed through the first opening 174 aof the second bank 174 in each subpixel area P. Here, a red light emitting layer 180r is formed on a red sub-pixel R, a green light emitting layer 180g is formed on a green sub-pixel G, and a blue light emitting layer 180b is formed on a blue sub-pixel B.Further, as shown in FIG. 3, a green light emitting layer 180 gis formed between the adjacent subpixel regions P of the same color, that is, on the first bank 172 exposed through the second opening 174 bof the second bank 174 between the green subpixels G, for example, on the first electrodes 162 in the subpixels G 3 and G 2, and on the first bank 172 between the subpixels G 3 and G 2. At this time, the green light emitting layer 180 gon the first bank 172 is connected to (or extends to) the green light emitting layers 180 gformed on the first electrodes 162 of the adjacent green sub-pixels G.The light emitting layer 180 is formed by a solution process. At this time, since the same color sub-pixels, for example, the green sub-pixels are connected to each other (for example, G 2, G 2, G 3, and G 4 in FIG. 2 are connected to each other in a diagonal direction), the solutions dropped into the green sub-pixels G through different nozzles are connected to each other. Accordingly, a deviation in drop amounts between the nozzles is minimized, and the thicknesses of the light emitting layers may be uniform in the respective sub-pixels G.Next, a second electrode 190 is formed on the light emitting layer 180 and the second bank 174.The first bank 162, the light emitting layer 180, and the second electrode 190 constitute a light emitting diode De.In this way, in the electroluminescent display device according to the second embodiment of the present disclosure, the number of red or blue sub-pixels R and B is half the number of green sub-pixels G, and the number of all sub-pixels is reduced. Therefore, the high aperture ratio can be secured and the effective resolution can be increased.Further, the same-color sub-pixels R, G, or B are arranged to be connected to each other, so that the light emitting layers 180 of the same-color sub-pixels R, G, or B are connected to each other, thereby forming a body. Thus, a deviation in drop amounts between the nozzles can be minimized, and the thicknesses of the thin films can be uniform in the respective sub-pixels R, G, and B. Accordingly, the unevenness can be prevented, so that the image quality of the display device can be prevented from being lowered.Meanwhile, although the (m-3)th column, the (m-2)th column, the (m-1)th column, and the mth column are sequentially arranged from the left side in FIG. 2, the arrangement of the m columns may be varied, and an example of such variation will now be discussed with reference to FIG. 4.FIG. 4 is a schematic view of another example of a pixel array of an electroluminescent display device according to the second embodiment of the present disclosure.The pixel array of FIG. 4 has substantially the same configuration as the pixel array of FIG. 2 except for the difference in the order in the left and right directions. The same parts are denoted by the same reference numerals, and descriptions of the same parts are omitted or are short.In FIG. 4, another example of the electroluminescent display device according to the second embodiment of the present disclosure includes red, green, and blue sub-pixels R, G, and B, and the same-color sub-pixels R, G, and B are arranged in a diagonal direction and connected to each other.As shown in FIG. 4, the (m-3)th column, the (m-2)th column, the (m-1)th column, and the mth column are arranged in order from right to left (as compared to the left-to-right arrangement of FIG. 2 ), but the number of the respective sub-pixels R, G, and B and the arrangement order of the same-color sub-pixels R, G, and B are the same as the number and the arrangement order in FIG. 2 ; thus, the green sub-pixels G of FIG. 4 extend along a diagonal direction different from the diagonal direction in which the green sub-pixels G 1-G 4 in FIG. 2 are connected to each other and are connected to each other in this direction. Regardless, all green sub-pixels G in FIG. 4 are still arranged in a diamond grid as in FIG. 2FIG. 5 is an equivalent circuit diagram of a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure. Each sub-pixel in the electroluminescent display device of FIGS. 2-4 may have the circuit configuration of FIG. 5.In FIG. 5, a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure includes a driving thin film transistor DTr, first, second, third, fourth, fifth, and sixth thin film transistors T 1, T 2, T 3, T 4. T5 and T6, a light emitting diode De and a storage capacitor Cst.Here, the first, second, third, fourth, fifth and sixth thin film transistors T1, T2, T3, T4, T5 and T6 and the driving thin film transistor DTr are p-type thin film transistors in which holes are used as carriers for transferring electric charges. However, the present disclosure is not limited thereto, and the first, second, third, fourth, fifth, and sixth thin film transistors T 1, T 2, T 3, T 4, T 5, and T 6 and the driving thin film transistor DTr may be n-type thin film transistors in which free electrons are used as carriers for transferring electric charges.Specifically, a gate of the first thin film transistor T 1 is connected to an n-th scan line for transmitting an n-th scan signal Scan(n) (n is a natural number), a source of the first thin film transistor T 1 is connected to a first node N 1, and a drain of the first thin film transistor T 1 is connected to a second node N 2. A gate of the second thin film transistor T2 is connected to the n-th scan line, a source of the second thin film transistor T2 is connected to a data line for supplying a data voltage Vdata, and a drain of the second thin film transistor T2 is connected to a third node N3. A gate of the third thin film transistor T 3 is connected to an emission control line for transmitting an emission control signal EM(n), a source of the third thin film transistor T 3 is connected to a high voltage supply line for supplying a high voltage VDD, and a drain of the third thin film transistor T 3 is connected to the third node N 3. A gate of the fourth thin film transistor T 4 is connected to the emission control line, a source of the fourth thin film transistor T 4 is connected to the second node N 2, and a drain of the fourth thin film transistor T 4 is connected to a fourth node N 4. A gate of the fifth thin film transistor T5 is connected to an (n-1)-th scan line for transmitting an (n-1)-th scan signal Scan(n-1), a source of the fifth thin film transistor T5 is connected to an initialization line for supplying an initialization voltage Vinit, and a drain of the fifth thin film transistor T5 is connected to the first node N1. A gate electrode of the sixth thin film transistor T 6 is connected to the (n-1)th scan line, a source of the sixth thin film transistor T 6 is connected to the initialization line, and a drain of the sixth thin film transistor T 6 is connected to the fourth node N 4.Further, a gate of the driving thin film transistor DTr is connected to the first node N 1, a source of the driving thin film transistor DTr is connected to the third node N 3, and a drain of the driving thin film transistor DTr is connected to the second node N 2.Meanwhile, a first capacitor electrode of the storage capacitor Cst is connected to the first node N 1, and a second capacitor electrode is connected to the high voltage supply line. In addition, an anode of the light emitting diode De is connected to the fourth node N 4, and a cathode of the light emitting diode De is connected to ground. Alternatively, the cathode of the light emitting diode De may be connected to a low voltage supply line for supplying a low voltage VSS.Thus, the gate of the driving thin film transistor DTr, the source of the first thin film transistor T 1, the drain of the fifth thin film transistor T 5, and the first capacitor electrode of the storage capacitor Cst are connected to the first node N 1. The drain of the driving thin film transistor DTr, the drain of the first thin film transistor T 1, and the source of the fourth thin film transistor T 4 are connected to the second node N 2. The source of the driving thin film transistor DTr, the drain of the second thin film transistor T 2, and the drain of the third thin film transistor T 3 are connected to the third node N 3. The drain of the fourth thin film transistor T 4, the drain of the sixth thin film transistor T 6, and the anode of the light emitting diode De are connected to the fourth node N 4.The storage capacitor Cst stores and holds a gate voltage and a threshold voltage Vth of the driving thin film transistor DTr until the next frame.The driving of the electroluminescent display device of FIG. 5 according to the second embodiment of the present disclosure will be described with reference to FIG. 6.FIG. 6 is a timing chart schematically illustrating a plurality of signals applied to a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure, and shows a frame.In FIG. 6, a frame F 1 includes first, second, and third periods t 1, t 2, and t 3. Here, the first period t 1 is a detection period, the second period t 2 is a programming period, and the third period t 3 is a light emission period. The first period t 1 may include an initialization step.In the first period t 1, the nth scan signal Scan(n) and the emission control signal EM(n) are at a high level. Thus, the first, second, third and fourth thin film transistors T1, T2, T3 and T4 are turned off.On the other hand, in the first period t1, the (n-1)th scan signal Scan(n-1) has a high level and then a low level, and when the (n-1)th scan signal Scan(n-1) has the low level, the fifth and sixth thin film transistors T5 and T6 are turned on. Thus, the initialization voltage Vinit is applied to the first node N 1 via the fifth thin film transistor T 5 and to the fourth node N 4 via the sixth thin film transistor T 6, and the first and fourth nodes N 1 and N 4 have the initialization voltage Vinit. Then, the (n-1)th scan signal Scan(n-1) again has a high level, and the fifth and sixth thin film transistors T5 and T6 are turned off.Next, in the second period t 2, the emission control signal EM(n) is at the high level, and the third and fourth thin film transistors T 3 and T 4 maintain the off state.On the other hand, in the second period t2, the (n-1)th scan signal Scan(n-1) has a high level and then a low level (and then a high level), whereas the n-th scan signal Scan(n) has a low level and then a high level.More specifically, when the (n-1)th scan signal Scan(n-1) is at the high level, both the fifth and sixth thin film transistors T5 and T6 are turned off while the n-th scan signal Scan(n) is at the low level, so that the first and second thin film transistors T1 and T2 are turned on. Accordingly, the data voltage Vdata is supplied to the third node N 3 via the second thin film transistor T 2, and the third node N 3 has the data voltage Vdata. Further, the initialization voltage Vinit of the first node N 1 is discharged via the first thin film transistor T 1 until a voltage of the first node N 1 is equal to a threshold voltage Vth of the driving thin film transistor DTr and the first node N 1 has the threshold voltage Vth. Then, the nth scan signal Scan(n) is at a high level, so that the first and second thin film transistors T 1 and T 2 are turned off and the threshold voltage Vth of the first node N 1 is stored in the storage capacitor Cst.Next, when the (n-1)th scan signal Scan(n-1) is at the low level, both the fifth and sixth thin film transistors T5 and T6 are turned on while the n-th scan signal Scan(n) is at the high level, so that the first and second thin film transistors T1 and T2 maintain the off state. At this time, the initialization voltage Vinit is applied to the first node N 1 via the fifth thin film transistor T 5 and to the fourth node N 4 via the sixth thin film transistor T 6. Accordingly, the first node N 1 has the sum of the stored threshold voltage Vth and the applied initialization voltage Vinit, and the fourth node N 4 has the initialization voltage Vinit.Next, in the third period t 3, the (n-1)th scan signal Scan(n-1) has a high level, and the fifth and sixth thin film transistors T 5 and T 6 are turned off.On the other hand, the nth scan signal Scan(n) is at a low level and then at a high level, and the emission control signal EM(n) is at a low level. When the nth scan signal Scan(n) is at the low level, the second thin film transistor T 2 is turned on and the data voltage Vdata is applied to the third node N 3. The emission control signal EM(n) is at the low level, and the third and fourth thin film transistors T 3 and T 4 are turned on, so that the light emitting diode De emits light according to the data voltage Vdata.The sub-pixel structure of the electroluminescent display device according to the second embodiment of the present disclosure will be described in more detail with reference to FIGS. 7 and 8.FIG. 7 is a schematic plan view of a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure.In FIG. 7, a scan line 122 is formed extending along a first direction (e.g., a row direction). The scan line 122 includes first and second scan lines 122 aand 122 bspaced apart from each other. The first scan line 122a corresponds to the (n-1)th scan line, and the second scan line 122b corresponds to the nth scan line. The sense line 122 may be referred to as a gate line. Here, the second scan line 122 bmay include a protrusion extending along a second direction (e.g., a column direction or a direction perpendicular to the first direction).In addition, an emission control line 124 and a first capacitor electrode 128 made of the same material are formed on the same layer as the sense line 122. Emission control line 124 is disposed adjacent to second sense line 122 band extends along the first direction away from second sense line 122 b. The first capacitor electrode 128 is disposed between the second sense line 122 band the emission control line 124.Then, a second capacitor electrode 132 and an initialization line 134 are formed on a layer other than the scan line 122. The second capacitor electrode 132 and the initialization line 134 may be formed of the same material as the scan line 122.The second capacitor electrode 132 is disposed between the second scan line 122 band the emission control line 124, and overlaps the first capacitor electrode 128 to form a storage capacitor Cst. The second capacitor electrode 132 has a capacitor hole 132a over the first capacitor electrode 128. The initialization line 134 is adjacent to the first scan line 122 aand extends along the first direction away from the first scan line 122 a.Next, a data line 151 and a high voltage supply line 152 are formed extending along the second direction. The data line 151 and the high voltage supply line 152 are formed on a layer other than the scan line 122, the emission control line 124, and the initialization line 134, and cross the scan line 122, the emission control line 124, and the initialization line 134. The high voltage supply line 152 overlaps the first and second capacitor electrodes 128 and 132 and is electrically connected to the second capacitor electrode 132. The data line 151 may be spaced apart from the first capacitor electrode 128 and overlap the second capacitor electrode 132.In addition, the first, second, and third electrode patterns 154, 156, and 158 made of the same material are formed on the same layer as the data line 151 and the high voltage supply line 152. The first electrode pattern 154 overlaps and crosses the second scan line 122 b, overlaps the first and second capacitor electrodes 128 and 132, and is electrically connected to the first capacitor electrode 128. The second electrode pattern 156 overlaps and crosses the emission control line 124. The third electrode pattern 158 overlaps and crosses the first scan line 134.Meanwhile, the semiconductor layer 112 is formed on a layer other than the first and second scan lines 122 aand 122 b, the emission control line 124, the first and second capacitor electrodes 128 and 132, the initialization line 134, the data line 151, the high voltage supply line 152, and the first, second, and third electrode patterns 154, 156, 158. The semiconductor layer 112 may be formed in a pattern in which a plurality of portions are integrally formed as one body and overlap and / or cross the first and second scan lines 122 aand 122 b, the emission control line 124, the first and second capacitor electrodes 128 and 132, the initialization line 134, the data line 151, the high voltage supply line 152, and the first, second, and third electrode patterns 154, 156, 158. The semiconductor layer 112 functions as an active layer and source and drain regions of each of the first, second, third, fourth, fifth and sixth thin film transistors T 1, T 2, T 3, T 4, T 5 and T 6 and a driving thin film transistor DTr, and may be doped with impurities corresponding to the source and drain regions.Here, the first thin film transistor T 1 and the second thin film transistor T 2 are connected to the second scan line 122 band are turned on and off. The third thin film transistor T 3 and the fourth thin film transistor T 4 are connected to the emission control line 124. The fifth thin film transistor T 5 and the sixth thin film transistor T 6 are connected to the first scan line 122 aand are turned on and off. At this time, the first and second scan lines 122 aand 122 band a part of the emission control line 124 are gate electrodes of the first, second, third, fourth, fifth, and sixth thin film transistors T 1, T 2, T 3, T 4, T 5, and T 6, and the part 126 of the emission control line becomes the gate electrode of the fourth thin film transistor T 4.In addition, the driving thin film transistor DTr is disposed between the second scan line 122 band the emission control line 124. The driving thin film transistor DTr is connected to the first, second, third, fourth and fifth thin film transistors T 1, T 2, T 3, T 4 and T 5 and the storage capacitor Cst.Meanwhile, the first electrode 162 is formed substantially in an entire area of the sub-pixel region to cover the first, second, third, fourth, fifth, and sixth thin film transistors T 1, T 2, T 3, T 4, T 5, and T 6, the driving thin film transistor DTr, and the storage capacitor Cst. The first electrode 162 is electrically connected to the driving thin film transistor DTr via the fourth thin film transistor T 4. Although the first electrode 162 is shown to be spaced apart from the data line 151, it is not limited thereto. That is, the first electrode 162 may partially overlap the data line 151. At this time, the first electrode 162 may overlap one of the opposing first and second sides of the data line 151 and be spaced apart from the other. Alternatively, the first electrode 162 may overlap both the first and second sides of the data line 151.Next, a first bank 172 is formed along the first direction. The first bank 172 has a hydrophilic property and is disposed between adjacent sub-pixels along the second direction. The first bank 172 covers both edges of the first electrode 162 facing each other along the second direction and exposes a central portion of the first electrode 162.Further, a second bank 174 is formed with a first opening 174a and a second opening 174b. The second bank 174 has a hydrophobic property and is disposed between adjacent sub-pixels along the first direction and between adjacent sub-pixels along the second direction. The second bank 174 covers both edges of the first electrode 162 facing along the first direction. The first opening 174 ais formed corresponding to the sub-pixel area and exposes the central portion of the first electrode 162. The second opening 174 bis formed corresponding to a region between the adjacent subpixel regions along a third direction crossing the first and second directions, and exposes the first bank 172.A light emitting layer is formed on the first electrode 162 exposed from the first and second banks 172 and 174. In addition, a light emitting layer is also formed on the first bank 172, which is exposed through the second opening 174 bof the second bank 174.Next, a second electrode is formed on the light emitting layer and the second bank 174 over a substantially entire surface of the substrate.The first electrode 162, the light emitting layer, and the second electrode constitute a light emitting diode.FIG. 8 is a schematic cross-sectional view of a sub-pixel of an electroluminescent display device according to the second embodiment of the present disclosure, and shows a cross-section corresponding to the line VIII-VIII' of FIG. 7.In FIG. 8, a buffer layer 110 is formed on substantially an entire surface of a substrate 100. The substrate 100 may be a glass substrate or a plastic substrate. For example, without limitation, polyimide may be used as the plastic substrate.The buffer layer 110 may be formed of an inorganic material such as silicon oxide (SiO 2) or silicon nitride (SiN x) and may be a single layer or multiple layers.A patterned semiconductor layer 112 is formed on the buffer layer 110. The semiconductor layer 112 may be formed of polycrystalline silicon, and the semiconductor layer 112 may be selectively doped with impurities. Alternatively, the semiconductor layer 112 may be formed of an oxide semiconductor material.A gate insulating film 120 made of an insulating material is formed on the semiconductor layer 112 substantially over the entire surface of the substrate 100. The gate insulating film 120 may be formed of an inorganic insulating material such as silicon oxide (SiO 2) or silicon nitride (SiN x). When the semiconductor layer 112 is made of an oxide semiconductor material, the gate insulating layer 120 is preferably made of silicon oxide (SiO 2).A gate electrode 126, an emission control line 124, and a first capacitor electrode 128 are formed on the gate insulating film 120 and are made of a first conductive material such as metal. Here, the gate electrode 126 is disposed on the semiconductor layer 112 and may be a part of the emission control line 124. In addition, the first capacitor electrode 128 partially overlaps the semiconductor layer 112.Meanwhile, the first and second scan lines 122 aand 122 bof FIG. 7 are further formed of the first conductive material on the gate insulating film 120.In the electroluminescent display device according to the second embodiment of the present disclosure, the gate insulating layer 120 is formed on the entire surface of the substrate 100. However, the gate insulating film 120 may be patterned to have the same shape as the gate electrode 126.A first insulating layer 130 made of an insulating material is formed on the gate electrode 126, the emission control line 124, and the first capacitor electrode 128 substantially over the entire surface of the substrate 100. The first insulating layer 130 may be formed of an inorganic insulating material such as silicon oxide (SiO 2) or silicon nitride (SiN x). Alternatively, the first insulating layer 130 may be formed of an organic insulating material such as photoacryl or benzocyclobutene.A second capacitor electrode 132 made of a second conductive material such as metal is formed on the first insulating layer 130. The second capacitor electrode 132 overlaps the first capacitor electrode 128, and has a capacitor hole 132 acorresponding to the first capacitor electrode 128. The first and second capacitor electrodes 128 and 132 and the first insulating layer 130 therebetween form a storage capacitor Cst.In addition, an initialization line 134 of FIG. 7 is further formed of the second conductive material such as metal on the first insulating layer 130.A second insulating layer 140 made of an insulating material is formed on the second capacitor electrode 132 substantially over the entire surface of the substrate 100. The second insulating layer 140 may be formed of an inorganic insulating material such as silicon oxide (SiO 2) or silicon nitride (SiN x). Alternatively, the second insulating layer 140 may be formed of an organic insulating material such as photoacryl or benzocyclobutene.The second insulating layer 140 includes a plurality of contact holes. At this time, the plurality of contact holes may also be formed in the first insulating layer 130 and / or the gate insulating layer 120 under the second insulating layer 140.For example, the second insulating layer 140 includes a first contact hole 140 athat exposes a part of the semiconductor layer 112 together with the first insulating layer 130 and the gate insulating layer 120, and a second contact hole 140 bthat exposes a part of the first capacitor electrode 128 together with the first insulating layer 130. The second insulating layer 140 has a third contact hole 140 cexposing a portion of the second capacitor electrode 132 thereunder. Here, the second contact hole 140 bis located in the capacitor hole 132 aof the second capacitor electrode 132.Next, a high voltage supply line 152, a first electrode pattern 154, and a second electrode pattern 156 made of a third conductive material such as metal are formed on the second insulating layer 140. The high voltage supply line 152 contacts the second capacitor electrode 132 via the third contact hole 140c, the first electrode pattern 154 contacts the first capacitor electrode 128 via the second contact hole 140b, and the second electrode pattern 156 contacts the semiconductor layer 112 via the first contact hole 140a. Here, the second electrode pattern 156 corresponds to the drain electrode of the fourth thin film transistor T 4 of FIG. 7.In addition, a data line 151 of FIG. 7 and a third electrode pattern 158 of the third conductive material are further formed on the second insulating layer 140.Then, a plating layer 160 made of an insulating material as a third insulating layer is formed on the high voltage supply line 152, the first electrode pattern 154, and the second electrode pattern 156 substantially over the entire surface of the substrate 100. The overcoat layer 160 may alleviate the step portions due to the underlying layers and have a flat top surface. The overcoat layer 160 may be formed of an organic insulating material such as photoacryl or benzocyclobutene.The overcoat layer 160 has a drain contact hole 160a exposing a portion of the second electrode pattern 156. The drain contact hole 160 amay be spaced apart from the first contact hole 140 a. However, the present disclosure is not limited thereto, and the drain contact hole 160 amay overlap the first contact hole 140 a.Next, a first electrode 162 is formed on the plating layer 160 and formed of a conductive material having a relatively high work function. The first electrode 162 is in contact with the second electrode pattern 156 through the drain contact hole 160 a. For example, the first electrode 162 may be formed of a transparent conductive material such as, but not limited to, indium tin oxide (ITO) or indium zinc oxide (IZO).Meanwhile, the electroluminescent display device according to the second embodiment of the present disclosure is an upward emission type in which light of a light emitting diode is output in a direction opposite to the substrate 100. Accordingly, the first electrode 162 may further include a reflective electrode or a reflective layer formed of a metal material having a relatively high reflectance, among the transparent conductive material. For example, the reflective electrode or reflective layer may be formed of an aluminum-palladium-copper (APC) alloy or silver (Ag). At this time, the first electrode 162 may have a three-layer structure of ITO / APC / ITO or ITO / Ag / ITO, but is not limited thereto.A first bank 172 is formed of an insulating material on the first electrode 162. The first bank 172 has a hydrophilic property and covers at least one edge of the first electrode 162. The first bank 172 may be formed of a material having a hydrophilic property, for example, an inorganic insulating material such as silicon oxide (SiO 2) or silicon nitride (SiN x). Alternatively, the first bank 172 may be formed of polyimide.A second bank 174 is formed on the first bank 172 and on the first electrode 162. The second bank 174 has a hydrophobic property and covers at least one edge of the first electrode 162. Additionally, the second bank 174 overlaps the first bank 172 and may cover at least one edge of the first bank 172. The second bank 174 may be formed of an organic insulating material having a hydrophobic property.The second bank 174 includes a plurality of first and second openings 174 aand 174 b. The first opening 174 a exposes the first electrode 162 and the second opening 174 b exposes the first bank 172.Further, a light emitting layer 180 is formed on the first electrode 162, and the first bank 172 is exposed through the first and second openings 174 aand 174 b.The light emitting layer 180 may include a first charge assist layer, a light emitting material layer, and a second charge assist layer sequentially positioned over the first electrode 162 and the first bank 172. The light emitting material layer may be formed of a red, green, or blue luminescent material, but is not limited thereto. The luminescent material may be an organic luminescent material such as a phosphorescent compound or a fluorescent compound, or may be an inorganic luminescent material such as a quantum dot.The first charge assist layer may be a hole assist layer, and the hole assist layer may include a hole injection layer (HIL) and / or a hole transport layer (HTL). In addition, the second charge assist layer may be an electron assist layer, and the electron assist layer may include an electron injection layer (EIL) and / or an electron transport layer (ETL). However, the present disclosure is not limited thereto, and other variations are possible.Further, the light emitting layer 180 is formed by a solution process. Thus, the process can be simplified and a display device having a large format and a high resolution can be provided. A spin coating method, an inkjet printing method, or a screen printing method may be used as the solution method, but the present disclosure is not limited thereto and other variations are possible.Meanwhile, the electron auxiliary layer of the light emitting layer 180 may be formed by an evaporation process. At this time, the electron auxiliary layer may be formed substantially over the entire surface of the substrate 100.A second electrode 190 made of a conductive material having a relatively low work function is formed on the light emitting layer 180 substantially over the entire surface of the substrate 100. Here, the second electrode 190 may be formed of aluminum (Al), magnesium (Mg), silver (Ag), or an alloy thereof. At this time, the second electrode 190 has a relatively thin thickness so that light from the light emitting layer 180 can be transmitted therethrough. Alternatively, the second electrode 190 may be formed of a transparent conductive material such as, but not limited to, indium gallium oxide (IGO).The first electrode 162, the light emitting layer 180, and the second electrode 190 constitute a light emitting diode De of each subpixel. Here, the first electrode 162 may serve as an anode and the second electrode 190 as a cathode, but the present disclosure is not limited thereto and other variations are possible.As described above, the electroluminescent display device according to the various examples of the second embodiment of the present disclosure may be an upward emission type in which light is output from the light emitting layer 180 of the light emitting diode De in a direction opposite to the substrate 200, that is, is output to the outside through the second electrode 190. The upward emission type display device may have a wider emission area than a downward emission type display device of the same size, so that brightness may be improved and power consumption may be reduced.At this time, the light emitting diode De of each subpixel may have an element thickness for a micro-cavity effect corresponding to a wavelength of the emitted light, thereby increasing the luminous efficiency. That is, the light emitting diodes De of the red, green, and blue sub-pixels may have different element thicknesses. Here, the element thickness may be defined as a distance between the first electrode 162 and the second electrode 190.Meanwhile, a protective layer and / or an encapsulation layer may be formed on the second electrode 190 substantially over the entire surface of the substrate 100 to block moisture or oxygen introduced from the outside, thereby protecting the light emitting diode De.< Embodiment>FIG. 9 is a schematic view of an electroluminescent display device according to a third embodiment of the present disclosure.The electroluminescent display device according to the third embodiment of the present disclosure further has a configuration of a non-display surface as compared with the electroluminescent display device according to the second embodiment, and has the same configuration of a display surface as that of the second embodiment. The same parts are denoted by the same reference numerals, and descriptions of the same parts are omitted or shortened.As shown in FIG. 9, in the electroluminescent display device according to the third embodiment of the present disclosure, a display area DA that displays an image and a non-display area NDA surrounding at least one or more sides of the display area DA are defined on the substrate. The display area DA may have the same pixel arrangement as those in FIGS. 2-8, and may be completely surrounded by the non-display areas NDA. In the display area DA, red, green, and blue sub-pixels R, G, and B are arranged in a matrix form, and same-color sub-pixels R, G, and B are arranged in a diagonal direction and connected to each other.Specifically, the red, green, and blue sub-pixels R, G, and B include red, green, and blue light emitting layers, respectively, and the sub-pixels R, G, and B of the display area DA are respectively connected to the sub-pixels R, G, and B of the non-display area NDA having the same colors. Accordingly, the sub-pixel R in the first row and the first column of the display area DA is connected to a sub-pixel R or more of the non-display area NDA in a diagonal direction. For example, as shown in FIG. 9, the sub-pixel R in the first row and the first column of the display area DA is connected to six sub-pixels R of the non-display area NDA (e.g., the sub-pixels R 5-R 11 are connected to each other in a diagonal direction), but is not limited thereto, and other variations are possible.Here, the red, green, and blue sub-pixels R, G, and B arranged in the non-display region NDA are dummy sub-pixels in which a thin film transistor and a storage capacitor are not formed. However, the sub-pixels R, G, and B of the non-display area NDA are not limited to those illustrated.Further, in the non-display area NDA, only the second bank 174 may be formed by omitting the first bank 172. In this case, when the light emitting layer is formed, the solution may be more included in the sub-pixels R, G, and B of the non-display area NDA than in the sub-pixels R, G, and B of the display area DA. Accordingly, the drying speed of the solvent can be made uniform in the central portion and the peripheral portion, thereby obtaining the light emitting layer having a more uniform thickness.Meanwhile, the first electrode (e.g., 162) in the red, green, and blue sub-pixels R, G, and B of the non-display area NDA may be omitted.As described above, in the third embodiment of the present disclosure, the sub-pixels R, G, and B of the display area DA are connected to the sub-pixels R, G, and B of the non-display area NDA, respectively. Thus, a deviation between nozzles with respect to all the sub-pixels R, G, and B of the display area DA can be minimized, thereby forming thin films having a uniform thickness in the respective sub-pixels R, G, and B.In the present disclosure, a mask is omitted by forming the light emitting layer of each sub-pixel by the solution process, thereby reducing manufacturing cost, and a large-format, high-resolution display device can be implemented.In addition, as part of the advantages offered by the present disclosure, the number of red sub-pixels and the number of blue sub-pixels may be half the number of green sub-pixels, and the number of all sub-pixels is reduced, so that the high aperture ratio can be ensured and the effective resolution can be increased.Moreover, the same color sub-pixels are connected to each other, and the light emitting layers of the same color sub-pixels are formed as one body, thereby minimizing the variation in dropping amount between the nozzles and uniformly forming the thicknesses of the light emitting layers of the sub-pixels. Therefore, the unevenness is prevented, thereby effectively preventing the image quality of the display device from being lowered.

Claims

An electroluminescent display device comprising: a plurality of sub-pixels (R, G, B) arranged in rows and columns on a substrate along a first direction and a second direction crossing the first direction, wherein the plurality of sub-pixels (R, G, B) comprises a plurality of first sub-pixels of a first color, a plurality of second sub-pixels of a second color, and a plurality of third sub-pixels of a third color, wherein the first color, the second color, and the third color are different from each other; and a light emitting diode (De) arranged in each of the plurality of sub-pixels (R, G, B) and comprising a first electrode (162), a light emitting layer (180), and a second electrode (190), wherein among the plurality of sub-pixels (R, G, b) a subpixel of an nth row and an mth column has the same color as a subpixel of an (n+1)th row and an (m-1)th column, wherein n is a natural number and m is a natural number greater than 4, and wherein, among the plurality of subpixels (R, G, B), a subpixel of the nth row and a kth column and a subpixel of the nth row and a (k-2)th column are first subpixels of the first color, wherein k is a natural number less than or equal to m, wherein the plurality of subpixels (R, G, B) are arranged in pixel matrices of 4x4 subpixels, and in one of the pixel arrays, four first sub-pixels having the first color are connected to each other in a diagonal direction, three second sub-pixels having the second color are connected to each other in the diagonal direction, and three third sub-pixels having the third color are connected to each other in the diagonal direction.The electroluminescent display device of claim 1, wherein a sub-pixel of the nth row and a (k-1)th column is a second sub-pixel having the second color, and a sub-pixel of the nth row and the (k-3)th column is a third sub-pixel having the third color.The electroluminescent display device of claim 2, wherein the first sub-pixels are green sub-pixels (G), and wherein one of the second sub-pixel and the third sub-pixel is a red sub-pixel (R) and the other of the second sub-pixel and the third sub-pixel is a blue sub-pixel (B).The electroluminescent display device according to any one of claims 1 to 3, wherein the light emitting layer (180) in the subpixel of the nth row and the mth column and the light emitting layer (180) in the subpixel of the (n+1)th row and the (m-1)th column are connected to each other.The electroluminescent display device of any preceding claim, further comprising: a first bank (172) covering an edge of the first electrode (162) and disposed between adjacent sub-pixels of the same color; and a second bank (174) covering an edge of the first bank (172) and disposed between adjacent sub-pixels of different color.The electroluminescent display device of claim 5, wherein the first bank (172) extends along the first direction and is disposed between adjacent sub-pixels extending along the second direction, and wherein the second bank (174) has a first opening (174a) and a second opening (174b), wherein the first opening (174a) corresponds to each of the plurality of sub-pixels (R, G, B), and the second opening (174b) corresponds to a region between the sub-pixel of the nth row and the mth column and the sub-pixel of the (n+1)th row and the (m-1)th column.The electroluminescent display device of claim 6, wherein the second opening (174b) connects the first opening (174a) corresponding to the subpixel of the nth row and the mth column to the first opening (174a) corresponding to the subpixel of the (n+1)th row and the (m-1)th column.The electroluminescent display device of any one of claims 6 or 7, wherein the first opening (174a) exposes the first electrode (162) and the second opening (174b) exposes the first opening (174a).The electroluminescent display device of claim 8, wherein the light emitting layer (180) is disposed on the exposed first electrode (162) and the exposed first opening (174a).The electroluminescent display device of any one of claims 5 to 9, wherein the first bank (172) has a hydrophilic property and the second bank (174) has a hydrophobic property.An electroluminescent display device comprising: a substrate on which a display area (DA) and a non-display area (NDA) are defined; and a plurality of sub-pixels (R, G, B) arranged in rows and columns and in pixel arrays of 4x4 sub-pixels in the display area (DA) and the non-display area (NDA), wherein the plurality of sub-pixels (R, G, B) include a plurality of first sub-pixels of a first color, a plurality of second sub-pixels of a second color, and a plurality of third sub-pixels of a third color, wherein the first color, the second color, and the third color are different from each other, wherein among the plurality of sub-pixels (R, G, b) in the display area (DA) and / or the non-display area (NDA), the subpixel of an nth row and an mth column has the same color as the subpixel of an (n+1)th row and an (m-1)th column, where n is a natural number and m is a natural number greater than 4, and in one of the pixel arrays, four first subpixels having the first color are connected to each other in a diagonal direction, three second subpixels having the second color are connected to each other in the diagonal direction, and three third subpixels having the third color are connected to each other in the diagonal direction, and among the plurality of subpixels (R, G, b) in the display area (DA) and / or the non-display area (NDA), a sub-pixel of the nth row and a kth column and a sub-pixel of the nth row and a (k-2)th column are first sub-pixels having the first color, where k is a natural number less than or equal to m.The electroluminescent display device according to claim 11, further comprising a first bank (172) between the sub-pixels with a light emitting layer (180) of the same color in the display area (DA).The electroluminescent display device according to claim 12, further comprising a second bank (174) between the sub-pixels having light emitting layers (180) of different colors in the display area (DA) and the non-display area (NDA).An electroluminescent display device comprising: a substrate in which a display area and a non-display area adjacent to the display area (DA) are provided; and a plurality of sub-pixels (R, G, B) arranged in pixel arrays of 4x4 sub-pixels along a row direction and a column direction on the substrate and including a connection area (150) in which four first color sub-pixels in one of the pixel arrays are connected to each other in a diagonal direction different from the row direction and the column direction, three second color sub-pixels in the pixel array are connected to each other in the diagonal direction, and three third color sub-pixels in the pixel array are connected to each other in the diagonal direction; a first bank (172) disposed on the substrate and having an opening extending in a non-diagonal direction and corresponding to a part of the plurality of sub-pixels (R, G, B); and a second bank (174) covering a portion of the first bank (172) and including a first opening (174a) corresponding to the opening of the first bank and a second opening (174b) corresponding to the connection area (150) of the sub-pixels of the same color.The electroluminescent display device of claim 14, wherein the second portion of the second bank (174) extending in the diagonal direction overlaps the first bank (172).

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