Display device of light-emitting device

Abstract

To provide a display device capable of preventing a light from being generated and discharged in an unintended region.SOLUTION: The present invention relates to a display device containing at least one of a positive hole transportation layer and an electric charge generation layer in a light-emitting device. The positive hole transportation layer and / or an electric charge generation layer of each pixel region can be separated from the positive hole transportation layer and / or the electric charge generation layer are in a pixel region to be adjacent. The positive hole transportation layer and / or the electric charge generation layer that are / is positioned to the pixel region indicating a blue can contain a p-type dopant in which it is smaller than that of the positive hole transportation layer and / or the electric charge generation layer positioned to the pixel region indicating a color that is not the blue. Thus, the display device can minimize a leak current. Therefore, the display device can improve an efficiency of each pixel region.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This specification relates to a display device in which a light-emitting element includes at least one hole transport layer and a charge generation layer.

Background Art

[0002] Generally, a display device provides an image to a user. For example, the display device can include a light-emitting element located on a pixel region. Each light-emitting element can emit light indicating a specific color. For example, each light-emitting element can include a light-emitting unit located between a lower electrode and an upper electrode. The light-emitting unit can include a number of light-emitting material layers. For example, the light-emitting unit can include at least one hole transport layer and a charge generation layer.

[0003] The image provided to the user can include various colors. For example, each pixel region can be one of a red pixel region indicating red, a green pixel region indicating green, and a blue pixel region indicating blue. The light-emitting unit of each pixel region can be connected to the light-emitting units of partially adjacent pixel regions. For example, the hole transport layer and the charge generation layer of each pixel region can be in direct contact with the hole transport layer and the charge generation layer of an adjacent pixel region. Thus, in the display device, a driving current applied to the light-emitting element of each pixel region can be supplied to the light-emitting element of an adjacent pixel region through the hole transport layer and / or the charge generation layer. That is, in the display device, light may be generated and emitted in an unintended region due to leakage current.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by this specification is to provide a display device capable of preventing light from being generated and emitted in an unintended region.

[0005] Another problem to be solved by this specification is to provide a display device in which the driving current applied to the light-emitting element of each light-emitting region cannot flow outside the light-emitting region.

[0006] The problems to be solved by this specification are not limited to the problems described above, and the problems not mentioned here will be clearly understandable to those skilled in the art from the following description.

Means for Solving the Problems

[0007] The display device according to the technical idea of this specification for achieving the problems to be solved includes an element substrate. The element substrate includes a first pixel region and a second pixel region. The first pixel region shows blue. The second pixel region shows a color different from that of the first pixel region. A first light-emitting element is located on the first pixel region. The first light-emitting element has a stacked structure of a first lower electrode, a first lower hole transport layer, a first lower light-emitting material layer, a first charge generation layer, a first upper light-emitting material layer, and a first upper electrode. A second light-emitting element is located on the second pixel region. The second light-emitting element has a stacked structure of a second lower electrode, a second lower hole transport layer, a second lower light-emitting material layer, a second charge generation layer, a second upper light-emitting material layer, and a second upper electrode. The second lower hole transport layer is separated from the first lower hole transport layer. The content of the p-type dopant in the first lower hole transport layer is lower than the content of the p-type dopant in the second lower hole transport layer.

[0008] The p-type dopant contained in the second lower hole transport layer can include the same substance as the p-type dopant contained in the first lower hole transport layer.

[0009] The first light-emitting element can include a first upper hole transport layer located between the first charge generation layer and the first upper light-emitting material layer. The second light-emitting element can include a second upper hole transport layer located between the second charge generation layer and the second upper light-emitting material layer. The second upper hole transport layer can be separated from the first upper hole transport layer.

[0010] The content of the p-type dopant in the first upper hole transport layer may be lower than the content of the p-type dopant in the second upper hole transport layer.

[0011] A third light-emitting element may be located on the third pixel region of the element substrate. The third light-emitting element may have a stacked structure including a third lower electrode, a third lower hole transport layer, a third lower light-emitting material layer, a third charge generation layer, a third upper light-emitting material layer, and a third upper electrode. The third pixel region can exhibit a color different from those of the first pixel region and the second pixel region. The third lower hole transport layer may be separated from the first lower hole transport layer and the second lower hole transport layer. The content of the p-type dopant in the third lower hole transport layer may be higher than the content of the p-type dopant in the first lower hole transport layer.

[0012] The second pixel region can exhibit green. The third pixel region can exhibit red. The content of the p-type dopant in the third lower hole transport layer may be higher than the content of the p-type dopant in the second lower hole transport layer.

[0013] The second lower light-emitting material layer may be separated from the first lower light-emitting material layer. The second upper light-emitting material layer may be separated from the first upper light-emitting material layer. The light emitted from the first upper light-emitting material layer can exhibit the same color as the light emitted from the first lower light-emitting material layer. The light emitted from the second upper light-emitting material layer can exhibit the same color as the light emitted from the second lower light-emitting material layer.

[0014] Each of the first charge generation layer and the second charge generation layer may have a stacked structure including an n-type charge generation layer and a p-type charge generation layer. The p-type charge generation layer of the second charge generation layer may be separated from the p-type charge generation layer of the first charge generation layer.

[0015] The display device according to the technical idea of the present invention for achieving other problems to be solved includes an element substrate. A first lower electrode is located on the first light-emitting region of the element substrate. A second lower electrode is located on the second light-emitting region of the element substrate. A light-emitting unit is located on the first lower electrode and the second lower electrode. The light-emitting unit has a stacked structure of a first light-emitting material layer, a charge generation layer, and a second light-emitting material layer. An upper electrode is located on the light-emitting unit. The upper electrode overlaps with the first light-emitting region and the second light-emitting region. The charge generation layer of the light-emitting unit has a stacked structure of an n-type charge generation layer and a p-type charge generation layer. The p-type charge generation layer overlapping with the second light-emitting region is separated from the p-type charge generation layer overlapping with the first light-emitting region. The content of the p-type dopant in the p-type charge generation layer located on the second light-emitting region is different from the content of the p-type dopant in the p-type charge generation layer located on the first light-emitting region.

[0016] The p-type dopant contained in the p-type charge generation layer located on the second light-emitting region can include the same substance as the p-type dopant contained in the p-type charge generation layer located on the first light-emitting region.

[0017] The light-emitting unit can include an upper hole transport layer located between the charge generation layer and the second light-emitting material layer. The upper hole transport layer overlapping with the second light-emitting region can be separated from the upper hole transport layer overlapping with the first light-emitting region. The content of the p-type dopant in the upper hole transport layer located on the second light-emitting region may be different from the content of the p-type dopant in the upper hole transport layer located on the first light-emitting region.

[0018] The content of the p-type dopant in the p-type charge generation layer located on the first light-emitting region may be lower than the content of the p-type dopant in the p-type charge generation layer located on the second light-emitting region. The content of the p-type dopant in the upper hole transport layer located on the first light-emitting region may be lower than the content of the p-type dopant in the upper hole transport layer located on the second light-emitting region.

[0019] A third lower electrode may be positioned on the third light-emitting region of the element substrate. The light-emitting unit and the upper electrode may extend on the third lower electrode. The p-type charge generation layer overlapping the third light-emitting region may be separated from the p-type charge generation layer overlapping the first light-emitting region and the p-type charge generation layer overlapping the second light-emitting region. The content of the p-type dopant in the p-type charge generation layer positioned on the third light-emitting region may be different from the content of the p-type dopant in the p-type charge generation layer positioned on the first light-emitting region.

[0020] The content of the p-type dopant in the p-type charge generation layer positioned on the third light-emitting region may be different from the content of the p-type dopant in the p-type charge generation layer positioned on the second light-emitting region.

[0021] A first color filter may be positioned between the first light-emitting region of the element substrate and the first lower electrode. A second color filter may be positioned between the second light-emitting region of the element substrate and the second lower electrode. The first light-emitting material layer and the second light-emitting material layer of the light-emitting unit may overlap the first light-emitting region and the second light-emitting region. The second color filter may include a material different from that of the first color filter.

Advantages of the Invention

[0022] The display device according to the technical idea of this specification includes a light-emitting unit positioned between the lower electrode and the upper electrode of each pixel region. The light-emitting unit includes at least one hole transport layer and a charge generation layer. The hole transport layer and / or the charge generation layer of the first pixel region showing blue is separated from the hole transport layer and / or the charge generation layer of the second pixel region showing a color different from that of the first pixel region, and the hole transport layer and / or the charge generation layer of the first pixel region can include a lower content of p-type dopant than the hole transport layer and / or the charge generation layer of the second pixel region. Therefore, the display device according to the technical idea of the present invention can minimize leakage current. Therefore, the display device according to the technical idea of the present invention can improve the efficiency of each pixel region. In addition, the display device according to the technical idea of the present invention can be driven with low power and can reduce power consumption.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0024] Details regarding the object, technical configuration, and resulting effects of the present invention will be more clearly understood from the following detailed description with reference to the drawings showing embodiments of the present invention. Here, the embodiments of the present invention are provided to fully convey the technical idea of the present invention to those skilled in the art, so the present invention can be embodied in other forms without being limited to the embodiments described below.

[0025] Also, parts denoted by the same reference numerals throughout the specification mean the same components, and in the drawings, the lengths and thicknesses of layers or regions may be exaggerated for the sake of convenience. Further, when it is described that the first component is "above" the second component, it includes not only the case where the first component is located directly above and in contact with the second component, but also the case where a third component is located between the first component and the second component.

[0026] Here, terms such as first, second, etc. are for explaining various components and are used for the purpose of distinguishing one component from another. However, within the scope not departing from the technical idea of the present invention, the first component and the second component can be arbitrarily named by those skilled in the art for convenience.

[0027] The terms used in the specification of the present invention are merely for explaining specific embodiments and are not intended to limit the present invention. For example, a component expressed in the singular includes a plurality of components unless it clearly means only the singular in the context. Also, in the specification of the present invention, terms such as "including" or "having" are intended to specify the existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that they do not pre-exclude the possibility of the existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those having ordinary knowledge in the technical field to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted to have a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or overly formal sense unless clearly defined in the specification of the present invention.

[0029] (Example) FIG. 1 is a diagram schematically showing a display device according to an embodiment of the present invention. FIG. 2 is a diagram showing a circuit of a pixel region of the display device according to an embodiment of the present invention.

[0030] Referring to FIGS. 1 and 2, a display device according to an embodiment of the present invention may include a display panel DP. The display panel DP can generate an image provided to a user. For example, a number of pixel regions PA may be located within the display panel DP. Various signals can be applied to each pixel region PA via signal wirings GL, DL, and PL. For example, the signal wirings GL, DL, and PL may include a gate line GL for applying a gate signal, a data line DL for applying a data signal, and a power voltage supply line PL for supplying a power voltage.

[0031] The gate line GL may be electrically connected to a gate driver GD. The data line DL may be electrically connected to a data driver DD. The power supply line PL may be electrically connected to a power unit PU. The gate driver GD and the data driver DD can be controlled by a timing controller TC. For example, the gate driver GD can receive a clock signal, a reset signal, and a start signal from the timing controller TC, and the data driver DD can receive digital video data and a source timing signal from the timing controller TC.

[0032] The display panel DP may include an active region AA where the pixel regions PA are located and a bezel region BZ located outside the active region AA. The pixel regions PA may be located within a region defined by the bezel region BZ. For example, the active region AA may be surrounded by the bezel region BZ. The gate driver GD, the data driver DD, the power unit PU, and the timing controller TC may be located outside the active region AA. For example, each signal wiring GL, DL, and PL may include a region overlapping with the bezel region BZ.

[0033] At least one of the gate driver GD, data driver DD, power supply unit PU, and timing controller TC may be located on the bezel area BZ. For example, the display device according to an embodiment of the present invention may be a GIP (Gate-In-Panel) type display device in which the gate driver GD is formed on the bezel area BZ.

[0034] Each pixel area PA can indicate a specific color. For example, a driving circuit DC electrically connected to the light emitting element 300 may be located within each pixel area PA. The driving circuit DC of each pixel area PA can control the light emitting element 300 of the pixel area PA according to a signal applied via the signal wirings GL, DL, and PL. The driving circuit DC of each pixel area PA can be electrically connected to the signal wirings GL, DL, and PL. For example, the driving circuit DC of each pixel area PA can be electrically connected to one of the gate lines GL, one of the data lines DL, and one of the power supply voltage supply lines PL. The driving circuit DC of each pixel area PA can supply a driving current corresponding to the data signal to the light emitting element 300 during one frame according to the gate signal. For example, the driving circuit DC of each pixel area PA can include a first thin film transistor TR1, a second thin film transistor TR2, and a storage capacitor Cst.

[0035] FIG. 3 is a diagram showing a cross section of a pixel area of a display device according to an embodiment of the present invention.

[0036] Referring to FIGS. 2 and 3, the first thin film transistor TR1 of each pixel area PA can transmit a data signal to the second thin film transistor TR2 according to a gate signal. For example, the first thin film transistor TR1 of each pixel area PA can function as a switching thin film transistor. The first thin film transistor TR1 of each pixel area PA can include a first semiconductor pattern, a first gate electrode, a first drain electrode, and a first source electrode. For example, the first gate electrode of each pixel area PA can be electrically connected to the gate line GL, and the first drain electrode of each pixel area PA can be electrically connected to the data line DL.

[0037] The first semiconductor pattern can include a semiconductor material. For example, the first semiconductor pattern can include an oxide semiconductor such as amorphous silicon (a-Si), polycrystalline silicon (poly-Si), and IGZO. The first semiconductor pattern can include a first drain region, a first channel region, and a first source region. The first channel region can be located between the first drain region and the first source region. The first drain region and the first source region can have a lower resistance than the first channel region. For example, the first drain region and the first source region can include a conductive region of an oxide semiconductor. The first channel region can be a region where the oxide semiconductor has not been made conductive.

[0038] The first gate electrode can be located on a partial region of the first semiconductor pattern. For example, the first gate electrode can overlap with the first channel region of the first semiconductor pattern. The first drain region and the first source region of the first semiconductor pattern can be located outside the first gate electrode. The first gate electrode can include a conductive material. For example, the first gate electrode can include a metal such as aluminum (Al), chromium (Cr), copper (Cu), molybdenum (Mo), titanium (Ti), and tungsten (W). The first gate electrode can be separated from the first semiconductor pattern. The first gate electrode can be insulated from the first semiconductor pattern. For example, the first drain region of the first semiconductor pattern can be electrically connected to the first source region of the first semiconductor pattern in response to a signal applied to the first gate electrode.

[0039] The first drain electrode can contain a conductive material. For example, the first drain electrode can contain metals such as aluminum (Al), chromium (Cr), copper (Cu), molybdenum (Mo), titanium (Ti), and tungsten (W). The first drain electrode can contain a material different from that of the first gate electrode. The first drain electrode can be located on a layer different from that of the first gate electrode. The first drain electrode can be electrically connected to the first drain region of the first semiconductor pattern. The first drain electrode can be insulated from the first gate electrode.

[0040] The first source electrode can contain a conductive material. For example, the first source electrode can contain metals such as aluminum (Al), chromium (Cr), copper (Cu), molybdenum (Mo), titanium (Ti), and tungsten (W). The first source electrode can contain a material different from that of the first gate electrode. The first source electrode can be located on a layer different from that of the first gate electrode. For example, the first source electrode can be located on the same layer as the first drain electrode. The first source electrode can contain the same material as the first drain electrode. The first source electrode can be formed in the same process as the first drain electrode. For example, the first source electrode can be formed simultaneously with the first drain electrode. The first source electrode can be electrically connected to the first source region of the first semiconductor pattern. The first source electrode can be insulated from the first gate electrode. The first source electrode can be separated from the first drain electrode.

[0041] The second thin film transistor TR2 in each pixel region PA can generate a drive current corresponding to a data signal. For example, the second thin film transistor TR2 in each pixel region PA can function as a drive thin film transistor. The second thin film transistor TR2 in each pixel region PA can include a second semiconductor pattern 221, a second gate electrode 223, a second drain electrode 225, and a second source electrode 227. For example, the second gate electrode 223 in each pixel region PA can be electrically connected to the first source electrode of the pixel region PA, and the second drain electrode 225 in each pixel region PA can be electrically connected to the power supply voltage supply line PL.

[0042] The second semiconductor pattern 221 can include a semiconductor material. For example, the second semiconductor pattern 221 can include an oxide semiconductor such as amorphous silicon (a-Si), polycrystalline silicon (poly-Si), and IGZO. The second semiconductor pattern 221 can include the same material as the first semiconductor pattern. The second semiconductor pattern 221 can be located on the same layer as the first semiconductor pattern. The second semiconductor pattern 221 can be formed in the same process as the first semiconductor pattern. For example, the second semiconductor pattern 221 can be formed simultaneously with the first semiconductor pattern.

[0043] The second semiconductor pattern 221 can include a second drain region, a second channel region, and a second source region. The second channel region can be located between the second drain region and the second source region. The second drain region and the second source region can have a lower resistance than the second channel region. For example, the second drain region and the second source region can include a conductive region of an oxide semiconductor. The second channel region can be a region where the oxide semiconductor has not been made conductive.

[0044] The second gate electrode 223 can be located on a partial region of the second semiconductor pattern 221. For example, the second gate electrode 223 can overlap with the second channel region of the second semiconductor pattern 221. The second drain region and the second source region of the second semiconductor pattern 221 can be located outside the second gate electrode 223. The second gate electrode 223 can include a conductive material. For example, the second gate electrode 223 can include a metal such as aluminum (Al), chromium (Cr), copper (Cu), molybdenum (Mo), titanium (Ti), and tungsten (W). The second gate electrode 223 can be separated from the second semiconductor pattern 221. The second gate electrode 223 can be insulated from the second semiconductor pattern 221. For example, the second channel region of the second semiconductor pattern 221 can have an electrical conductivity corresponding to the voltage applied to the second gate electrode 223.

[0045] The second gate electrode 223 can contain the same material as the first gate electrode. The second gate electrode 223 can be located on the same layer as the first gate electrode. The second gate electrode 223 can be formed in the same process as the first gate electrode. For example, the second gate electrode 223 can be formed simultaneously with the first gate electrode.

[0046] The second drain electrode 225 can contain a conductive material. For example, the second drain electrode 225 can contain metals such as aluminum (Al), chromium (Cr), copper (Cu), molybdenum (Mo), titanium (Ti), and tungsten (W). The second drain electrode 225 can contain a material different from that of the second gate electrode 223. The second drain electrode 225 can be located on a layer different from that of the second gate electrode 223. The second drain electrode 225 can be electrically connected to the second drain region of the second semiconductor pattern 221. The second drain electrode 225 can be insulated from the second gate electrode 223.

[0047] The second drain electrode 225 can contain the same material as the first drain electrode. The second drain electrode 225 can be located on the same layer as the first drain electrode. The second drain electrode 225 can be formed in the same process as the first drain electrode. For example, the second drain electrode 225 can be formed simultaneously with the first drain electrode.

[0048] The second source electrode 227 can include a conductive material. The second source electrode 227 can include metals such as aluminum (Al), chromium (Cr), copper (Cu), molybdenum (Mo), titanium (Ti), and tungsten (W). The second source electrode 227 can include a material different from that of the second gate electrode 223. The second source electrode 227 can be located on a layer different from that of the second gate electrode 223. For example, the second source electrode 227 can be located on the same layer as the second drain electrode 225. The second source electrode 227 can include the same material as the second drain electrode 225. The second source electrode 227 can be formed in the same process as the second drain electrode 225. For example, the second source electrode 227 can be formed simultaneously with the second drain electrode 225. The second source electrode 227 can be electrically connected to the second source region of the second semiconductor pattern 221. The second source electrode 227 can be insulated from the second gate electrode 223. The second source electrode 227 can be separated from the second drain electrode 225.

[0049] The storage capacitor Cst of each pixel region PA can maintain the voltage applied to the second gate electrode 223 of the pixel region PA for one frame. For example, the storage capacitor Cst of each pixel region PA can be electrically connected to the second gate electrode 223 and the second source electrode 227 of the pixel region PA. The storage capacitor Cst of each pixel region PA can have a stacked structure of capacitor electrodes. For example, the storage capacitor Cst of each pixel region PA can include a first capacitor electrode electrically connected to the second gate electrode 223 of the pixel region PA and a second capacitor electrode electrically connected to the second source electrode 227 of the pixel region PA.

[0050] The storage capacitor Cst of each pixel region PA can be formed using the process of forming the first thin film transistor TR1 and the second thin film transistor TR2 of the pixel region PA. For example, the first capacitor electrode of each pixel region PA is located on the same layer as the second gate electrode 223 of the pixel region PA, and the second capacitor electrode of each pixel region PA can be located on the same layer as the second source electrode 227 of the pixel region PA. The first capacitor electrode of each pixel region PA contains the same material as the second gate electrode 223 of the pixel region PA, and the second capacitor electrode of each pixel region PA can contain the same material as the second source electrode 227 of the pixel region PA. The first capacitor electrode of each pixel region PA is formed in the same process as the second gate electrode 223 of the pixel region PA, and the second capacitor electrode of each pixel region PA can be formed in the same process as the second source electrode 227 of the pixel region PA. For example, the first capacitor electrode of each pixel region PA can be formed simultaneously with the second gate electrode 223 of the pixel region PA, and the second capacitor electrode of each pixel region PA can be formed simultaneously with the second source electrode 227 of the pixel region PA.

[0051] The drive circuit DC and the light emitting element 300 of each pixel region PA can be supported by the element substrate 100. For example, the first thin film transistor TR1, the second thin film transistor TR2, and the storage capacitor Cst of each pixel region PA can be located on the element substrate 100. The element substrate 100 can contain an insulating material. For example, the element substrate 100 can contain glass or plastic.

[0052] A number of insulating films 110, 120, 130, 140, 150, 160 for preventing unnecessary electrical connections can be located on the element substrate 100. For example, a buffer insulating film 110, a gate insulating film 120, an interlayer insulating film 130, an element protection film 140, a planarization film 150, and a bank insulating film 160 can be located on the element substrate 100.

[0053] The buffer insulating film 110 can be located close to the element substrate 100. The buffer insulating film 110 can prevent contamination by the element substrate 100 during the process of forming the drive circuit DC in each pixel region PA. For example, the upper surface of the element substrate 100 facing the drive circuit DC in each pixel region PA can be completely covered by the buffer insulating film 110. The first thin film transistor TR1, the second thin film transistor TR2, and the storage capacitor Cst in each pixel region PA can be located on the buffer insulating film 110. The buffer insulating film 110 can contain an insulating substance. For example, the buffer insulating film 110 can contain an inorganic insulating substance such as silicon oxide (SiOx) and silicon nitride (SiNx). The buffer insulating film 110 can have a multilayer structure. For example, the buffer insulating film 110 can have a structure in which an inorganic insulating film made of silicon oxide (SiOx) and an inorganic insulating film made of silicon nitride (SiNx) are laminated.

[0054] The gate insulating film 120 can be located on the buffer insulating film 110. The first gate electrode in each pixel region PA can be insulated from the first semiconductor pattern in the pixel region PA by the gate insulating film 120. The second gate electrode 223 in each pixel region PA can be insulated from the second semiconductor pattern 221 in the pixel region PA by the gate insulating film 120. For example, the gate insulating film 120 can cover the first semiconductor pattern and the second semiconductor pattern 221 in each pixel region PA. The first gate electrode and the second gate electrode 223 in each pixel region PA can be located on the gate insulating film 120. The gate insulating film 120 can contain an insulating substance. For example, the gate insulating film 120 can contain an inorganic insulating substance such as silicon oxide (SiOx) and silicon nitride (SiNx).

[0055] The interlayer insulating film 130 can be located on the gate insulating film 120. The first drain electrode and the first source electrode of each pixel region PA can be insulated from the first gate electrode of the pixel region PA by the interlayer insulating film 130. The second drain electrode 225 and the second source electrode 227 of each pixel region PA can be insulated from the second gate electrode 223 of the pixel region PA by the interlayer insulating film 130. For example, the interlayer insulating film 130 can cover the first gate electrode and the second gate electrode 223 of each pixel region PA. The first drain electrode, the first source electrode, the second drain electrode 225, and the second source electrode 227 of each pixel region PA can be located on the interlayer insulating film 130. The interlayer insulating film 130 can contain an insulating material. For example, the interlayer insulating film 130 can contain an inorganic insulating material.

[0056] The element protection film 140 can be located on the interlayer insulating film 130. The element protection film 140 can prevent damage to the drive circuit DC located inside each pixel region PA due to external impact and moisture. The element protection film 140 can extend along the upper surface of the drive circuit DC located inside each pixel region PA facing the element substrate 100. For example, the first drain electrode, the first source electrode, the second drain electrode 225, and the second source electrode 227 of each pixel region PA can be covered by the element protection film 140. The first drain electrode of each pixel region PA can penetrate the gate insulating film 120 and the interlayer insulating film 130 to directly contact the first drain region of the pixel region PA, and the first source electrode of each pixel region PA can penetrate the gate insulating film 120 and the interlayer insulating film 130 to directly contact the first source region of the pixel region PA. The second drain electrode 225 of each pixel region PA can penetrate the gate insulating film 120 and the interlayer insulating film 130 to directly contact the second drain region of the pixel region PA, and the second source electrode 227 of each pixel region PA can penetrate the gate insulating film 120 and the interlayer insulating film 130 to directly contact the second source region of the pixel region PA. The element protection film 140 can contain an insulating material. For example, the element protection film 140 can contain an inorganic insulating material.

[0057] The planarization film 150 can be located on the element protection film 140. The planarization film 150 can remove the step caused by the driving circuit DC in each pixel region PA. For example, the upper surface of the planarization film 150 facing the element substrate 100 can be a flat plane. The upper surface of the planarization film 150 can be parallel to the upper surface of the element substrate 100. The planarization film 150 can contain an insulating material. The planarization film 150 can contain a material different from the element protection film 140. The planarization film 150 can contain a material with relatively high fluidity. For example, the planarization film 150 can contain an organic insulating material.

[0058] The light-emitting element 300 in each pixel region PA can be located on the upper surface of the planarization film 150. The light-emitting element 300 in each pixel region PA can emit light indicating a specific color. For example, the light-emitting element 300 in each pixel region PA can include a lower electrode 310, a light-emitting unit 320, and an upper electrode 330 that are sequentially stacked on the planarization film 150 of the pixel region PA.

[0059] The light-emitting unit 320 can generate light with a luminance corresponding to the voltage difference between the lower electrode 310 and the upper electrode 330. For example, the light-emitting unit 320 can include an emission material layer (EML). The emission material layer can include an organic light-emitting material, an inorganic light-emitting material, or a hybrid light-emitting material. For example, the display device according to an embodiment of the present invention can be an organic light-emitting display device in which the light-emitting unit 320 includes an organic light-emitting material.

[0060] The lower electrode 310 and the upper electrode 330 can contain a conductive material. The upper electrode 330 can contain a material different from that of the lower electrode 310. The reflectivity of the lower electrode 310 may be higher than that of the upper electrode 330. The upper electrode 330 may have a transmittance higher than that of the lower electrode 310. For example, the lower electrode 310 can contain metals such as aluminum (Al) and silver (Ag), and the upper electrode 330 can be a transparent electrode made of a transparent conductive material such as ITO and IZO. The lower electrode 310 can have a multilayer structure. For example, the lower electrode 310 can have a structure in which a reflective electrode made of a metal is positioned between transparent electrodes made of a transparent conductive material such as ITO and IZO. Therefore, in the display device according to an embodiment of the present invention, the light generated by the light-emitting unit 320 in each pixel region PA can be emitted to the outside through the upper electrode 330 of the pixel region PA.

[0061] The bank insulating film 160 can be positioned on the planarization film 150. The bank insulating film 160 can define a light-emitting region R-EA, G-EA, and B-EA within each pixel region PA. The region between the light-emitting regions R-EA, G-EA, and B-EA can be defined as a non-light-emitting region NEA. For example, the bank insulating film 160 can overlap with the non-light-emitting region NEA of the element substrate 100. A partial region of the lower electrode 310 positioned within each pixel region PA can be exposed by the bank insulating film 160. For example, the bank insulating film 160 can cover the edge portion of the lower electrode 310 positioned within each pixel region PA. The bank insulating film 160 can contain an insulating material. For example, the bank insulating film 160 can contain an organic insulating material. The bank insulating film 160 can contain a material different from that of the planarization film 150. The lower electrode 310 of each pixel region PA can be insulated from the lower electrode 310 of an adjacent pixel region PA by the bank insulating film 160.

[0062] The lower electrode 310 of each pixel region PA can be electrically connected to the second thin film transistor TR2 of the driving circuit DC located within the pixel region PA. For example, the lower electrode 310 of each pixel region PA can penetrate the element protection film 140 and the planarization film 150 and directly contact the second source electrode 227 of the pixel region PA. The second source electrode 227 and the lower electrode 310 of each pixel region PA can be electrically connected within the non-emitting region NEA of the pixel region PA. For example, a partial region of the lower electrode 310 located within the light-emitting regions R-EA, G-EA, and B-EA of each pixel region PA can directly contact the upper surface of the planarization film 150. The light-emitting unit 320 and the upper electrode 330 of each pixel region PA can be stacked on a partial region of the lower electrode 310 exposed by the bank insulating film 160. That is, in the display device according to an embodiment of the present invention, the light-emitting unit 320 and the upper electrode 330 of each pixel region PA can be stacked on a partial region of the lower electrode 310 that overlaps the light-emitting region EA of the pixel region PA. Therefore, the display device according to an embodiment of the present invention can prevent luminance deviation due to the light generation position of the light emitted from each pixel region PA.

[0063] A plurality of light-emitting material layers EML can be located within the light-emitting unit 320 of each pixel region PA. For example, as shown in FIGS. 3 and 4, the light-emitting unit 320 of each pixel region PA can include a first light-emitting stack 321, a charge generation layer 322, and a second light-emitting stack 323 stacked in sequence. Each of the first light-emitting stack 321 and the second light-emitting stack 323 can include at least one light-emitting material layer EML. The charge generation layer 322 can supply electrons or holes to the first light-emitting stack 321 and the second light-emitting stack 323. For example, the charge generation layer 322 can have a stacked structure of an n-type charge generation layer 322n and a p-type charge generation layer 322p. Each of the first light-emitting stack 321 and the second light-emitting stack 323 can emit light.

[0064] Each of the first light-emitting stack 321 and the second light-emitting stack 323 can further include at least one functional layer for smooth supply of holes or electrons. The functional layer can be one of a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL). For example, the first light-emitting stack 321 includes a hole injection layer 321hi, a first hole transport layer 321ht, a first light-emitting material layer 321em, and a first electron transport layer 321et, and the second light-emitting stack 323 can include a second hole transport layer 323ht, a second light-emitting material layer 323em, a second electron transport layer 323et, and an electron injection layer 323ei. The first electrode 310 can function as an anode electrode, and the second electrode 330 can function as a cathode electrode. For example, the work-function of the first electrode 310 may be higher than that of the second electrode 330. The p-type charge generation layer 322p of the charge generation layer 322 can be located between the n-type charge generation layer 322n of the charge generation layer 322 and the second hole transport layer 323ht of the second light-emitting stack 323.

[0065] The light generated by the second light-emitting stack 323 can exhibit the same color as the light generated by the first light-emitting stack 321. For example, the light-emitting material layer EML of the second light-emitting stack 323 can include the same material as the light-emitting material layer EML of the first light-emitting stack 321. The wavelength range of the light generated by the second light-emitting stack 323 can be the same as the wavelength range of the light generated by the first light-emitting stack 321. Therefore, the display device according to the embodiment of the present invention can improve the color reproducibility of the light emitted from each pixel region PA.

[0066] The image provided to the user can include various colors. The light emitted from the light-emitting regions R-EA, G-EA, and B-EA of each pixel region PA can exhibit colors different from those of the light-emitting regions R-EA, G-EA, and B-EA of adjacent pixel regions PA. For example, the light-emitting regions R-EA, G-EA, and B-EA of each pixel region PA can be one of the red light-emitting region R-EA of a red pixel region that emits red light, the green light-emitting region G-EA of a green pixel region that emits green light, and the blue light-emitting region B-EA of a blue pixel region that emits blue light. The first light-emitting material layer 321em of each light-emitting region R-EA, G-EA, B-EA is separated from the first light-emitting material layers 321em of adjacent light-emitting regions R-EA, G-EA, B-EA on the non-light-emitting region NEA, and the second light-emitting material layer 323em of each light-emitting region R-EA, G-EA, B-EA can be separated from the second light-emitting material layers 323em of adjacent light-emitting regions R-EA, G-EA, B-EA on the non-light-emitting region NEA.

[0067] At least a part of the hole injection layer 321hi, the first hole transport layer 321ht, the p-type charge generation layer 322p, and the second hole transport layer 323ht of each light-emitting region R-EA, G-EA, B-EA can be doped with a p-type dopant. Here, the term "doped" means that a substance having physical properties different from those of the substance is added to the substance that occupies most of the weight ratio of the layer. For example, each of the hole injection layer 321hi, the first hole transport layer 321ht, the p-type charge generation layer 322p, and the second hole transport layer 323ht of each light-emitting region R-EA, G-EA, B-EA can include a p-type dopant having a weight ratio of less than 30% of the layer. Therefore, the display device according to an embodiment of the present invention can improve the hole injection efficiency into the first light-emitting material layer 321em and / or the second light-emitting material layer 323em of each light-emitting region R-EA, G-EA, B-EA through the hole injection layer 321hi, the first hole transport layer 321ht, the p-type charge generation layer 322p, and the second hole transport layer 323ht of each light-emitting region R-EA, G-EA, B-EA.

[0068] A p-type dopant can use various substances. For example, boron can be doped into at least a part of the hole injection layer 321hi, the first hole transport layer 321ht, and the second hole transport layer 323ht in each of the light-emitting regions R-EA, G-EA, and B-EA. The p-type charge generation layer 322p in each of the light-emitting regions R-EA, G-EA, and B-EA can be a p-type charge generating material containing an inorganic substance selected from the group consisting of tungsten oxide (WOx), molybdenum oxide (MoOx), beryllium oxide (Be2O3), vanadium oxide (V2O5), and combinations thereof, NPD, HAT-CN, F4TCNQ, TPD, TNB, TCTA, N, N'-dioctyl-3,4,9,10-perylenedicarboximide (N, N'-dioctyl-3,4,9,10-perylenedicarboximide; PTCDI-C8), an indacene derivative, and an organic substance selected from the group consisting of combinations thereof.

[0069] Each of the hole injection layers 321hi, the first hole transport layers 321ht, the p-type charge generation layers 322p, and the second hole transport layers 323ht of the light-emitting regions R-EA, G-EA, and B-EA can be separated from the hole injection layers 321hi, the first hole transport layers 321ht, the p-type charge generation layers 322p, and the second hole transport layers 323ht of the adjacent light-emitting regions R-EA, G-EA, and B-EA on the non-light-emitting region NEA. For example, the hole injection layer 321hi of each of the light-emitting regions R-EA, G-EA, and B-EA is separated from the hole injection layer 321hi of the adjacent light-emitting regions R-EA, G-EA, and B-EA, the first hole transport layer 321ht of each of the light-emitting regions R-EA, G-EA, and B-EA is separated from the first hole transport layer 321ht of the adjacent light-emitting regions R-EA, G-EA, and B-EA, and the second hole transport layer 323ht of each of the light-emitting regions R-EA, G-EA, and B-EA can be separated from the second hole transport layer 323ht of the adjacent light-emitting regions R-EA, G-EA, and B-EA. The p-type charge generation layer 322p of each of the light-emitting regions R-EA, G-EA, and B-EA can be separated from the p-type charge generation layer 322p of the adjacent light-emitting regions R-EA, G-EA, and B-EA. Therefore, the display device according to the embodiment of the present invention can prevent leakage current through the hole injection layer 321hi, the first hole transport layer 321ht, the p-type charge generation layer 322p, and the second hole transport layer 323ht of each of the light-emitting regions R-EA, G-EA, and B-EA.

[0070] Table 1 below shows the difference in threshold voltage (ΔVth) and relative leakage current (%Δu'v') between adjacent light-emitting regions according to the content of the p-type dopant doped in the first hole transport layer 321ht located in the red light-emitting region R-EA, green light-emitting region G-EA, and blue light-emitting region B-EA in the display device according to the embodiment of the present invention. Here, the p-type dopant doped in the first hole transport layer 321ht of the red light-emitting region R-EA, green light-emitting region G-EA, and blue light-emitting region B-EA can contain the same substance. Also, ΔVth(G-R) means the value obtained by subtracting the threshold voltage of the red light-emitting region R-EA from the threshold voltage of the green light-emitting region G-EA, and ΔVth(B-G) means the value obtained by subtracting the threshold voltage of the green light-emitting region G-EA from the threshold voltage of the blue light-emitting region B-EA.

Table 1

[0071] Referring to Table 1, when the first hole transport layer 321ht in the blue light emitting region B-EA is doped with a relatively low content of p-type dopant, the leakage current can be reduced. Therefore, in the display device according to an embodiment of the present invention, the first hole transport layer 321ht in the blue light emitting region B-EA contains a lower content of p-type dopant than the first hole transport layer 321ht in the red light emitting region R-EA and the first hole transport layer 321ht in the green light emitting region G-EA, so that the leakage current can be reduced. Also, referring to Table 1, when the content of the p-type dopant doped in the first hole transport layer 321ht in the green light emitting region G-EA is between the content of the p-type dopant doped in the first hole transport layer 321ht in the red light emitting region R-EA and the content of the p-type dopant doped in the first hole transport layer 321ht in the blue light emitting region B-EA, the leakage current can be significantly reduced. Therefore, in the display device according to an embodiment of the present invention, the content of the p-type dopant in the first hole transport layer 321ht in the green light emitting region G-EA is higher than the content of the p-type dopant in the first hole transport layer 321ht in the blue light emitting region B-EA, and the content of the p-type dopant in the first hole transport layer 321ht in the red light emitting region R-EA is higher than the content of the p-type dopant in the first hole transport layer 321ht in the green light emitting region G-EA, so that the leakage current can be minimized. Also, the display device according to an embodiment of the present invention can improve the efficiency of each of the light emitting regions R-EA, G-EA, and B-EA. Further, referring to Table 1, when the p-type dopant contained in the first hole transport layer 321ht in the blue light emitting region B-EA has a relatively low content, the threshold voltage of the red light emitting region R-EA and the threshold voltage of the green light emitting region G-EA can be lower than the threshold voltage of the blue light emitting region B-EA. That is, in the display device according to an embodiment of the present invention, by doping the first hole transport layer 321ht in the blue light emitting region B-EA with a lower content of p-type dopant than the first hole transport layer 321ht in the red light emitting region R-EA and the first hole transport layer 321ht in the green light emitting region G-EA, a driving current can be supplied to the light emitting elements 300 in the red light emitting region R-EA and the light emitting elements 300 in the green light emitting region G-EA, which have relatively low efficiency, earlier than to the light emitting elements 300 in the blue light emitting region B-EA.Therefore, the display device according to an embodiment of the present invention can prevent a quality degradation of a low gray-scale image due to an efficiency difference of the light-emitting elements 300 located in the light-emitting regions R-EA, G-EA, and B-EA of each pixel region PA.

[0072] A sealing structure 400 may be located on the light-emitting element 300 of each pixel region PA. The sealing structure 400 can prevent damage to the light-emitting element 300 located in each pixel region PA caused by external impact and moisture. The sealing structure 400 may have a multilayer structure. For example, the sealing structure 400 may include a first sealing layer 410, a second sealing layer 420, and a third sealing layer 430 sequentially stacked on the second electrode 330 of each pixel region PA. The first sealing layer 410, the second sealing layer 420, and the third sealing layer 430 may include an insulating material. The second sealing layer 420 may include a material different from those of the first sealing layer 410 and the third sealing layer 430. The second sealing layer 420 may include a material having higher fluidity than those of the first sealing layer 410 and the third sealing layer 430. For example, the first sealing layer 410 and the third sealing layer 430 may be inorganic insulating films made of an inorganic insulating material, and the second sealing layer 420 may be an organic insulating film made of an organic insulating material. Therefore, the display device according to an embodiment of the present invention can effectively prevent damage to the light-emitting element 300 located in each pixel region PA caused by external impact and moisture. The step difference caused by the light-emitting element 300 of each pixel region PA can be removed by the second sealing layer 420. The second sealing layer 420 may have a greater thickness than those of the first sealing layer 410 and the third sealing layer 430. For example, the upper surface of the sealing structure 400 facing the element substrate 100 may be a flat plane.

[0073] As a result, the display device according to an embodiment of the present invention includes a light-emitting unit 320 positioned between a lower electrode 310 and an upper electrode 330 of each of the light-emitting regions R-EA, G-EA, and B-EA, and the light-emitting units 320 of each of the light-emitting regions R-EA, G-EA, and B-EA include a hole injection layer 321hi, a first hole transport layer 321ht, a first light-emitting material layer 321em, a p-type charge generation layer 322p, a second hole transport layer 323ht, and a second light-emitting material layer 323em that are separated from the light-emitting units 320 of the adjacent light-emitting regions R-EA, G-EA, and B-EA on the bank insulating film 160. The content of the p-type dopant in the first hole transport layer 321ht of the blue light-emitting region B-EA can be lower than the content of the p-type dopant in the first hole transport layer 321ht of the red light-emitting region R-EA and the content of the p-type dopant in the first hole transport layer 321ht of the green light-emitting region G-EA. Therefore, the display device according to an embodiment of the present invention can reduce or minimize leakage current and improve the efficiency of each of the light-emitting regions R-EA, G-EA, and B-EA. In addition, the display device according to an embodiment of the present invention can prevent a quality degradation of a low-tone image due to an efficiency difference of the light-emitting elements 300 positioned in each of the light-emitting regions R-EA, G-EA, and B-EA. Therefore, the display device according to an embodiment of the present invention can improve the quality of an image provided to a user.

[0074] In the display device according to an embodiment of the present invention, color filters 500R, 500G, and 500B may be located on the sealing structure 400. The color filters 500R, 500G, and 500B may overlap with the light emitting regions R-EA, G-EA, and B-EA. Each of the color filters 500R, 500G, and 500B may overlap with one of the light emitting regions R-EA, G-EA, and B-EA. For example, the color filters 500R, 500G, and 500B may include a red color filter 500R that overlaps with the red light emitting region R-EA, a green color filter 500G that overlaps with the green light emitting region G-EA, and a blue color filter 500B that overlaps with the blue light emitting region B-EA. Light emitted from the light emitting regions R-EA, G-EA, and B-EA of each pixel region PA can pass through the color filters 500R, 500G, and 500B of the pixel region PA and be emitted to the outside. For example, the size of each of the color filters 500R, 500G, and 500B may be larger than the size of the light emitting regions R-EA, G-EA, and B-EA. Therefore, the display device according to an embodiment of the present invention can effectively improve the color reproducibility of the light emitted from each of the light emitting regions R-EA, G-EA, and B-EA.

[0075] A filter protection film 600 may be located on the color filters 500R, 500G, and 500B of each pixel region PA. The filter protection film 600 can prevent damage to the color filters 500R, 500G, and 500B caused by external impact and moisture. For example, the color filters 500R, 500G, and 500B of each pixel region PA can be completely covered by the filter protection film 600. The filter protection film 600 can contain an insulating material. For example, the filter protection film 600 can contain at least one of an inorganic insulating material and an organic insulating material. The filter protection film 600 can have a multilayer structure. For example, the filter protection film 600 can have a structure in which an inorganic protection film made of an inorganic insulating material is formed on an organic protection film made of an organic insulating material. Steps caused by the color filters 500R, 500G, and 500B can be removed by the filter protection film 600. Therefore, the display device according to the embodiment of the present invention can effectively prevent damage to the color filters 500R, 500G, and 500B located in each pixel region PA caused by external impact and moisture.

[0076] In the display device according to an embodiment of the present invention, the drive circuit DC in each pixel region PA is composed of a first thin film transistor TR1, a second thin film transistor TR2, and a storage capacitor Cst. However, in the display device according to another embodiment of the present invention, the drive circuit DC in each pixel region PA can include a driving thin film transistor and at least one switching thin film transistor. For example, in the display device according to another embodiment of the present invention, the drive circuit DC in each pixel region PA can further include a third thin film transistor for initializing the storage capacitor Cst in the pixel region PA according to a gate signal. The third thin film transistor in each pixel region PA can include a third semiconductor pattern, a third gate electrode, a third drain electrode, and a third source electrode. The third semiconductor pattern in each pixel region PA can include a semiconductor material. The third gate electrode in each pixel region PA can be electrically connected to the gate line GL. The third drain electrode in each pixel region PA can be electrically connected to an initialization line to which an initialization signal is applied. The third source electrode in each pixel region PA can be electrically connected to the storage capacitor Cst in the pixel region PA. Therefore, in the display device according to another embodiment of the present invention, the degree of freedom in the configuration of each drive circuit DC can be improved.

[0077] In the display device according to an embodiment of the present invention, the first drain electrode, the first source electrode, the second drain electrode 225, and the second source electrode 227 of each drive circuit DC can have different positions and electrical connections depending on the configuration of the drive circuit DC and / or the types of the thin film transistors TR1 and TR2. For example, in the display device according to another embodiment of the present invention, the second gate electrode 223 of each drive circuit DC can be electrically connected to the first drain electrode of the drive circuit DC. Therefore, in the display device according to another embodiment of the present invention, the degree of freedom in the configuration of each drive circuit DC and the types of the thin film transistors TR1 and TR2 can be improved.

[0078] In the display device according to an embodiment of the present invention, the first hole transport layer 321ht in the blue emission region B-EA contains a p-type dopant with a lower content than the first hole transport layer 321ht in the red emission region R-EA and the first hole transport layer 321ht in the green emission region G-EA. However, in the display device according to another embodiment of the present invention, the second hole transport layer 323ht in the blue emission region B-EA can contain a p-type dopant with a lower content than the second hole transport layer 323ht in the red emission region R-EA and the second hole transport layer 323ht in the green emission region G-EA. Therefore, the display device according to another embodiment of the present invention can improve the degree of freedom in the configuration of the light-emitting unit 320 located in each of the red emission regions R-EA, G-EA, and B-EA.

[0079] In a display device according to another embodiment of the present invention, the first hole transport layer 321ht in the blue emission region B-EA contains a lower content of a p-type dopant than the first hole transport layer 321ht in the red emission region R-EA and the first hole transport layer 321ht in the green emission region G-EA, and the second hole transport layer 323ht in the blue emission region B-EA can contain a lower content of a p-type dopant than the second hole transport layer 323ht in the red emission region R-EA and the second hole transport layer 323ht in the green emission region G-EA. For example, in a display device according to another embodiment of the present invention, the content of the p-type dopant in the first hole transport layer 321ht in the green emission region G-EA is between the content of the p-type dopant in the first hole transport layer 321ht in the blue emission region B-EA and the content of the p-type dopant in the first hole transport layer 321ht in the red emission region R-EA, and the content of the p-type dopant in the second hole transport layer 323ht in the green emission region G-EA can be between the content of the p-type dopant in the second hole transport layer 323ht in the blue emission region B-EA and the content of the p-type dopant in the second hole transport layer 323ht in the red emission region R-EA. Therefore, the display device according to another embodiment of the present invention can significantly reduce leakage current and improve the efficiency of the light-emitting elements 300 located in each of the emission regions R-EA, G-EA, and B-EA. In addition, the display device according to another embodiment of the present invention can significantly improve the quality degradation of low-tone images due to the efficiency difference of the light-emitting elements 300 located in each of the emission regions R-EA, G-EA, and B-EA.

[0080] According to another embodiment of the present invention, in the display device, the content of the p-type dopant in the p-type charge generation layer 322p of each of the light-emitting regions R-EA, G-EA, and B-EA can be the same as the content of the p-type dopant in the p-type charge generation layer 322p of the adjacent light-emitting regions R-EA, G-EA, and B-EA. For example, according to another embodiment of the present invention, in the display device, the step of doping the p-type charge generation layer 322p of the blue light-emitting region B-EA with a p-type dopant can be executed simultaneously with the step of doping the p-type charge generation layer 322p of the red light-emitting region R-EA with a p-type dopant and the step of doping the p-type charge generation layer 322p of the green light-emitting region G-EA with a p-type dopant. Therefore, according to another embodiment of the present invention, in the display device, the step of forming the p-type charge generation layer 322p in each of the light-emitting regions R-EA, G-EA, and B-EA can be simplified.

[0081] According to another embodiment of the present invention, in the display device, the p-type charge generation layer 322p of each of the light-emitting regions R-EA, G-EA, and B-EA can be formed simultaneously with the p-type charge generation layer 322p of the adjacent light-emitting regions R-EA, G-EA, and B-EA. For example, as shown in FIG. 5, according to another embodiment of the present invention, in the display device, the p-type charge generation layer 322p of each of the light-emitting regions R-EA, G-EA, and B-EA can be in direct contact with the p-type charge generation layer 322p of the adjacent light-emitting regions R-EA, G-EA, and B-EA. Therefore, according to another embodiment of the present invention, in the display device, the process efficiency can be improved.

[0082] According to another embodiment of the present invention, in the display device, the content of the p-type dopant doped in the first hole transport layer 321ht and the second hole transport layer 323ht of each of the light-emitting regions R-EA, G-EA, and B-EA is the same, and the p-type dopant contained in the p-type charge generation layer 322p of each of the light-emitting regions R-EA, G-EA, and B-EA may be different from the p-type dopant contained in the p-type charge generation layer 322p of the adjacent light-emitting regions R-EA, G-EA, and B-EA. For example, as shown in FIG. 6, in the display device according to another embodiment of the present invention, the first hole transport layer 321ht of each of the light-emitting regions R-EA, G-EA, and B-EA is in direct contact with the first hole transport layer 321ht of the adjacent light-emitting regions R-EA, G-EA, and B-EA, the second hole transport layer 323ht of each of the light-emitting regions R-EA, G-EA, and B-EA is in direct contact with the second hole transport layer 323ht of the adjacent light-emitting regions R-EA, G-EA, and B-EA, and the p-type charge generation layer 322p of each of the light-emitting regions R-EA, G-EA, and B-EA may be separated from the p-type charge generation layer 322p of the adjacent light-emitting regions R-EA, G-EA, and B-EA on the bank insulating film 160.

[0083] Table 2 below shows the difference in threshold voltage (ΔVth) and relative leakage current (%Δu’v’) between adjacent light-emitting regions according to the content of the p-type dopant doped in the p-type charge generation layer 322p located in the red light-emitting region R-EA, green light-emitting region G-EA, and blue light-emitting region B-EA in a display device according to another embodiment of the present invention, in which the content of the p-type dopant in the first hole transport layer 321ht and the second hole transport layer 323ht of each of the light-emitting regions R-EA, G-EA, and B-EA is the same.

Table 2

[0084] Referring to Table 2, when the p-type charge generation layer 322p in the blue light-emitting region B-EA is doped with a relatively low content of p-type dopant, the difference between the threshold voltage of the red light-emitting region R-EA, the threshold voltage of the green light-emitting region G-EA, and the threshold voltage of the blue light-emitting region B-EA increases, and the leakage current can be reduced. Therefore, in the display device according to another embodiment of the present invention, the content of the p-type dopant doped in the first hole transport layer 321ht and the second hole transport layer 323ht in each of the light-emitting regions R-EA, G-EA, and B-EA is the same, and the p-type charge generation layer 322p in the blue light-emitting region B-EA can contain a lower content of p-type dopant than the p-type charge generation layer 322p in the red light-emitting region R-EA and the p-type charge generation layer 322p in the green light-emitting region G-EA. Also, referring to Table 2, when the content of the p-type dopant doped in the p-type charge generation layer 322p in the green light-emitting region G-EA is between the content of the p-type dopant doped in the p-type charge generation layer 322p in the red light-emitting region R-EA and the content of the p-type dopant doped in the p-type charge generation layer 322p in the blue light-emitting region B-EA, the leakage current can be significantly reduced. That is, in the display device according to the embodiment of the present invention, the content of the p-type dopant doped in the first hole transport layer 321ht and the second hole transport layer 323ht in each of the light-emitting regions R-EA, G-EA, and B-EA is the same, the content of the p-type dopant in the p-type charge generation layer 322p in the green light-emitting region G-EA is higher than the content of the p-type dopant in the p-type charge generation layer 322p in the blue light-emitting region B-EA, and the content of the p-type dopant in the p-type charge generation layer 322p in the red light-emitting region R-EA is higher than the content of the p-type dopant in the p-type charge generation layer 322p in the green light-emitting region G-EA, whereby the leakage current can be minimized. Therefore, the display device according to another embodiment of the present invention can reduce or minimize the leakage current, prevent the quality degradation of low-tone images, and improve the degree of freedom in the configuration of the light-emitting unit 320 located in each of the light-emitting regions R-EA, G-EA, and B-EA.In a display device according to another embodiment of the present invention, the content of the p-type dopant doped in the first hole transport layer 321ht of the blue light emitting region B-EA is lower than the content of the p-type dopant doped in the first hole transport layer 321ht of the red light emitting region R-EA and the content of the p-type dopant doped in the first hole transport layer 321ht of the green light emitting region G-EA, and the p-type dopant contained in the p-type charge generation layer 322p of the blue light emitting region B-EA may have a lower content than the p-type dopant contained in the p-type charge generation layer 322p of the red light emitting region R-EA and the p-type dopant contained in the p-type charge generation layer 322p of the green light emitting region G-EA.

[0085] Table 3 below shows the difference in threshold voltage (ΔVth) and relative leakage current (%Δu'v') between adjacent light emitting regions due to the content of the p-type dopant doped in the first hole transport layer 321ht and the p-type charge generation layer 322p located in the red light emitting region R-EA, green light emitting region G-EA, and blue light emitting region B-EA in a display device according to another embodiment of the present invention.

Table 3

[0086] Referring to Table 3, when the first hole transport layer 321ht and the p-type charge generation layer 322p in the blue light-emitting region B-EA are doped with a relatively low content of p-type dopant, the difference between the threshold voltage of the red light-emitting region R-EA, the threshold voltage of the green light-emitting region G-EA, and the threshold voltage of the blue light-emitting region B-EA increases, and the leakage current can be reduced. That is, in the display device according to another embodiment of the present invention, the first hole transport layer 321ht in the blue light-emitting region B-EA contains a lower content of p-type dopant than the first hole transport layer 321ht in the red light-emitting region R-EA and the first hole transport layer 321ht in the p-green light-emitting region G-EA, and the p-type charge generation layer 322p in the blue light-emitting region B-EA can contain a lower content of p-type dopant than the p-type charge generation layer 322p in the red light-emitting region R-EA and the p-type charge generation layer 322p in the green light-emitting region G-EA. Also, in the display device according to an embodiment of the present invention, the content of the p-type dopant in the first hole transport layer 321ht in the green light-emitting region G-EA is lower than the content of the p-type dopant in the first hole transport layer 321ht in the red light-emitting region R-EA, and the content of the p-type dopant in the first hole transport layer 321ht in the blue light-emitting region B-EA can be lower than the content of the p-type dopant in the first hole transport layer 321ht in the green light-emitting region G-EA. Therefore, the display device according to an embodiment of the present invention can reduce or minimize the leakage current and prevent the quality degradation of low-tone images. Further, referring to Table 3, when the p-type dopant contained in the p-type charge generation layer 322p in the blue light-emitting region B-EA has a relatively low content, the difference between the threshold voltage of the red light-emitting region R-EA and the threshold voltage of the green light-emitting region G-EA can increase.Therefore, in the display device according to the embodiment of the present invention, each of the first hole transport layer 321ht and the p-type charge generation layer 322p in the green light-emitting region G-EA contains a lower content of p-type dopant than the first hole transport layer 321ht and the p-type charge generation layer 322p in the red light-emitting region R-EA, and each of the first hole transport layer 321ht and the p-type charge generation layer 322p in the blue light-emitting region B-EA contains a lower content of p-type dopant than the first hole transport layer 321ht and the p-type charge generation layer 322p in the green light-emitting region G-EA, thereby minimizing leakage current, and the threshold voltages of the respective light-emitting regions R-EA, G-EA, B-EA may be different from the threshold voltages of the light-emitting regions R-EA, G-EA, B-EA that exhibit colors different from those of the light-emitting regions R-EA, G-EA, B-EA. Therefore, the display device according to the embodiment of the present invention can effectively prevent the quality degradation of the low-tone image due to the efficiency difference of the light-emitting elements located in the light-emitting regions R-EA, G-EA, B-EA of each pixel region.

[0087] In the display device according to another embodiment of the present invention, the content of the p-type dopant doped in the p-type charge generation layer 322p of each of the light-emitting regions R-EA, G-EA, B-EA may not be significantly different from the content of the p-type dopant doped in the first hole transport layer 321ht of the light-emitting regions R-EA, G-EA, B-EA. That is, in the display device according to another embodiment of the present invention, the first light-emitting stack 321 and the second light-emitting stack 323 in each of the light-emitting regions R-EA, G-EA, B-EA may have similar resistances. Therefore, the display device according to another embodiment of the present invention can prevent leakage current due to the resistance difference between the first light-emitting stack 321 and the second light-emitting stack 323 stacked in each of the light-emitting regions R-EA, G-EA, B-EA. Therefore, the display device according to the embodiment of the present invention can effectively reduce or minimize leakage current.

[0088] In the display device according to an embodiment of the present invention, the light emitted from the light-emitting element 300 in each pixel region PA exhibits a color different from the light emitted from the light-emitting element 300 in an adjacent pixel region PA. However, in the display device according to another embodiment of the present invention, the light emitted from the light-emitting element 300 in each pixel region PA can exhibit the same color as the light emitted from the light-emitting element 300 in an adjacent pixel region PA. For example, in the display device according to another embodiment of the present invention, the light-emitting element 300 in each pixel region PA can emit white light. That is, in the display device according to another embodiment of the present invention, various color images can be realized through a color filter positioned on the pixel region PA. Thus, the light-emitting unit 320 in each pixel region PA can have the same stacked structure as the light-emitting unit 320 in an adjacent pixel region PA. The light-emitting unit 320 in each pixel region PA can be formed in the same process as the light-emitting unit 320 in an adjacent pixel region PA. For example, the light-emitting unit 320 in each pixel region PA can be formed simultaneously with the light-emitting unit 320 in an adjacent pixel region PA. Thus, in the display device according to another embodiment of the present invention, the process of forming the light-emitting unit 320 in each pixel region PA can be simplified.

[0089] In the display device according to an embodiment of the present invention, color filters 500R, 500G, and 500B are located on the encapsulation structure 400. However, in the display device according to another embodiment of the present invention, the light emitted from the light-emitting element 300 in each pixel region PA can be emitted to the outside through the lower electrode 310 and the element substrate 100 of the pixel region PA. For example, as shown in FIG. 7, in the display device according to another embodiment of the present invention, color filters 500R, 500B, and 500G in each pixel region R-PA, G-PA, and B-PA can be located between the element protection film 140 and the planarization film 150 of the pixel regions R-PA, G-PA, and B-PA. For example, in the display device according to another embodiment of the present invention, the red color filter 500R is located between the element protection film 140 and the planarization film 150 of the red pixel region R-PA, the green color filter 500G is located between the element protection film 140 and the planarization film 150 of the green pixel region G-PA, and the blue color filter 500B can be located between the element protection film 140 and the planarization film 150 of the blue pixel region B-PA. The color filters 500R, 500G, and 500B can be completely covered by the planarization film 150. For example, the step caused by the color filters 500R, 500G, and 500B can be removed by the planarization film 150.

[0090] The transmittance of the lower electrode 310 may be higher than the transmittance of the upper electrode 330. The upper electrode 330 can have a higher reflectance than the lower electrode 310. For example, in the display device according to another embodiment of the present invention, the lower electrode 310 is a transparent electrode made of the same transparent conductive material as ITO and IZO, and the upper electrode 330 can include a metal such as aluminum (Al) and silver (Ag). Therefore, in the display device according to another embodiment of the present invention, the degree of freedom in the configuration of the light-emitting unit 320 located in each light-emitting region R-EA, G-EA, and B-EA can be improved.

[0091] Referring to FIGS. 7 and 8, a display device according to another embodiment of the present invention may include a first light-emitting stack 321, a first charge generation layer 322, a second light-emitting stack 323, a second charge generation layer 324, and a third light-emitting stack 325 in which the light-emitting units 320 of each pixel region R-PA, G-PA, B-PA are stacked in order. Light emitted from at least one of the first light-emitting stack 321, the second light-emitting stack 323, and the third light-emitting stack 325 of each pixel region R-PA, G-PA, B-PA may exhibit a color different from that of light emitted from the other light-emitting stacks 321, 323, 325 of the pixel regions R-PA, G-PA, B-PA. For example, at least one of the light-emitting stacks of each pixel region R-PA, G-PA, B-PA may generate light showing blue, and at least one of the light-emitting stacks of each pixel region R-PA, G-PA, B-PA may generate light showing a color complementary to blue. For example, in a display device according to another embodiment of the present invention, the first light-emitting material layer 321em of the first light-emitting stack 321 and the third light-emitting material layer 325em of the third light-emitting stack 325 located in each pixel region R-PA, G-PA, B-PA are blue light-emitting material layers containing a blue fluorescent dopant, and the light generated by the second light-emitting material layer 323em of the second light-emitting stack 323 located in each pixel region R-PA, G-PA, B-PA may show yellow. The second light-emitting material layer 323em may have a multilayer structure. For example, the second light-emitting material layer 323em may have a stacked structure of a red light-emitting material layer and a green light-emitting material layer, or a stacked structure of a red light-emitting material layer, a yellow-green light-emitting material layer, and a green light-emitting material layer.

[0092] The hole injection layer 321hi, the first hole transport layer 321ht, and the first light-emitting material layer 321em of the first light-emitting stack 321 located within each pixel region R-PA, G-PA, B-PA can be separated from the hole injection layer 321hi, the first hole transport layer 321ht, and the first light-emitting material layer 321em of the first light-emitting stack 321 located within the adjacent pixel regions R-PA, G-PA, B-PA on the bank insulating film 160. The second hole transport layer 323ht and the second light-emitting material layer 323em of the second light-emitting stack 323 located within each pixel region R-PA, G-PA, B-PA can be separated from the second hole transport layer 323ht and the second light-emitting material layer 323em of the second light-emitting stack 323 located within the adjacent pixel regions R-PA, G-PA, B-PA on the bank insulating film 160. The third hole transport layer 325ht and the third light-emitting material layer 325em of the third light-emitting stack 325 located within each pixel region R-PA, G-PA, B-PA can be separated from the third hole transport layer 325ht and the third light-emitting material layer 325em of the third light-emitting stack 325 located within the adjacent pixel regions R-PA, G-PA, B-PA on the bank insulating film 160. The p-type charge generation layer 322p of the first charge generation layer 322 and the p-type charge generation layer 324p of the second charge generation layer 324 located within each pixel region R-PA, G-PA, B-PA can be separated from the p-type charge generation layer 322p of the first charge generation layer 322 and the p-type charge generation layer 324p of the second charge generation layer 324 located within the adjacent pixel regions R-PA, G-PA, B-PA on the bank insulating film 160. Therefore, the display device according to another embodiment of the present invention can improve the degree of freedom with respect to the configuration of the light-emitting unit 320 located within each pixel region R-PA, G-PA, B-PA.

[0093] As shown in FIG. 9, in a display device according to another embodiment of the present invention, a light-emitting unit 320 positioned between a lower electrode 310 and an upper electrode 330 in each pixel region may have a stacked structure including a light-emitting stack 321 including a red light-emitting material layer 321re, a light-emitting stack 325 including a green light-emitting material layer 321ge, and light-emitting stacks 323, 327 including blue light-emitting material layers 323be, 327be. For example, in a display device according to another embodiment of the present invention, a light-emitting unit 320 in each pixel region may include a first light-emitting stack 321, a first charge generation layer 322, a second light-emitting stack 323, a second charge generation layer 324, a third light-emitting stack 325, a third charge generation layer 326, and a fourth light-emitting stack 327, the first light-emitting stack 321 includes a red light-emitting material layer 321re, the third light-emitting stack 325 includes a green light-emitting material layer 321ge, and each of the second light-emitting stack 323 and the fourth light-emitting stack 327 may include blue light-emitting material layers 323be, 327be. Each of the first charge generation layer 322, the second charge generation layer 324, and the third charge generation layer 326 may have a stacked structure including n-type charge generation layers 322n, 324n, 326n and p-type charge generation layers 322p, 324p, 326p.

[0094] The hole injection layer 321hi, the first hole transport layer 321ht, and the red light-emitting material layer 321re of each pixel region can be separated from the hole injection layer 321hi, the first hole transport layer 321ht, and the red light-emitting material layer 321re of the adjacent pixel regions on the bank insulating film 160. The p-type charge generation layer 322p of the first charge generation layer 322 located within each pixel region can be separated from the p-type charge generation layer 322p of the first charge generation layer 322 located within the adjacent pixel regions on the bank insulating film 160. The second hole transport layer 323ht and the blue light-emitting material layer 323be of the second light-emitting stack 323 located within each pixel region can be separated from the second hole transport layer 323ht and the blue light-emitting material layer 323be of the second light-emitting stack 323 located within the adjacent pixel regions on the bank insulating film 160. The p-type charge generation layer 324p of the second charge generation layer 324 located within each pixel region can be separated from the p-type charge generation layer 324p of the second charge generation layer 324 located within the adjacent pixel regions on the bank insulating film 160. The third hole transport layer 325ht and the green light-emitting material layer 325ge of each pixel region can be separated from the third hole transport layer 325ht and the green light-emitting material layer 325ge of the adjacent pixel regions on the bank insulating film 160. The p-type charge generation layer 326p of the third charge generation layer 326 located within each pixel region can be separated from the p-type charge generation layer 326p of the third charge generation layer 326 of the adjacent pixel regions on the bank insulating film 160. The fourth hole transport layer 327ht and the blue light-emitting material layer 327be of the fourth light-emitting stack 327 located within each pixel region can be separated from the blue light-emitting material layer 327be of the fourth light-emitting stack 327 of the adjacent pixel regions on the bank insulating film 160. The first electron transport layer 321et and the n-type charge generation layer 322n of the first charge generation layer 322 located within each pixel region can be in direct contact with the first electron transport layer 321et and the n-type charge generation layer 322n of the first charge generation layer 322 located within the adjacent pixel regions. The second electron transport layer 323et and the n-type charge generation layer 324n of the second charge generation layer 324 located within each pixel region can be in direct contact with the second electron transport layer 323et and the n-type charge generation layer 324n of the second charge generation layer 324 located within the adjacent pixel regions.The n-type charge generation layer 326n of the third electron transport layer 325et and the third charge generation layer 326 located within each pixel region can be in direct contact with the n-type charge generation layer 326n of the third electron transport layer 325et and the third charge generation layer 326 located within an adjacent pixel region. The fourth electron transport layer 327et and the electron injection layer 327ei located within each pixel region can be in direct contact with the fourth electron transport layer 327et and the electron injection layer 327ei located within an adjacent pixel region. Thus, the display device according to another embodiment of the present invention can reduce or minimize leakage current and improve the efficiency of the light-emitting elements located on each pixel region, regardless of the configuration of the light-emitting unit 320 located on each pixel region.

Explanation of Signs

[0095] 100 Element substrate 300 Light-emitting element 310 Lower electrode 320 Light-emitting unit 321 First light-emitting stack 321ht First hole transport layer 322 Charge generation layer 322n n-type charge generation layer 322p p-type charge generation layer 323 Second light-emitting stack 330 Upper electrode

Claims

1. An element substrate including a first pixel region showing blue and a second pixel region showing a color different from that of the first pixel region, A first light-emitting element located on the first pixel region of the element substrate and having a stacked structure of a first lower electrode, a first lower hole transport layer, a first lower light-emitting material layer, a first charge generation layer, a first upper light-emitting material layer, and a first upper electrode, A second light-emitting element located on the second pixel region of the element substrate and having a stacked structure of a second lower electrode, a second lower hole transport layer, a second lower light-emitting material layer, a second charge generation layer, a second upper light-emitting material layer, and a second upper electrode, and including, The second lower hole transport layer is separated from the first lower hole transport layer between the first pixel region and the second pixel region, A display device in which the content of the p-type dopant in the first lower hole transport layer is lower than the content of the p-type dopant in the second lower hole transport layer.

2. The display device according to claim 1, wherein the p-type dopant contained in the second lower hole transport layer contains the same substance as the p-type dopant contained in the first lower hole transport layer.

3. The first light-emitting element includes a first upper hole transport layer located between the first charge generation layer and the first upper light-emitting material layer, The second light-emitting element includes a second upper hole transport layer located between the second charge generation layer and the second upper light-emitting material layer, The display device according to claim 1, wherein the second upper hole transport layer is separated from the first upper hole transport layer.

4. The display device according to claim 3, wherein the content of the p-type dopant in the first upper hole transport layer is lower than the content of the p-type dopant in the second upper hole transport layer.

5. Further including a third light-emitting element located on a third pixel region of the element substrate and having a stacked structure of a third lower electrode, a third lower hole transport layer, a third lower light-emitting material layer, a third charge generation layer, a third upper light-emitting material layer, and a third upper electrode, The third pixel region shows a color different from that of the first pixel region and the second pixel region, The third lower hole transport layer is separated from the first lower hole transport layer and the second lower hole transport layer, The display device according to claim 1, wherein the content of the p-type dopant in the third lower hole transport layer is higher than the content of the p-type dopant in the first lower hole transport layer.

6. The second pixel region shows green, The third pixel region shows red, The display device according to claim 5, wherein the content of the p-type dopant in the third lower hole transport layer is higher than the content of the p-type dopant in the second lower hole transport layer.

7. Each of the second lower light-emitting material layer and the second upper light-emitting material layer is separated from the first lower light-emitting material layer and the first upper light-emitting material layer, The light emitted from the first upper light-emitting material layer shows the same color as the light emitted from the first lower light-emitting material layer, The display device according to claim 1, wherein the light emitted from the second upper light-emitting material layer shows the same color as the light emitted from the second lower light-emitting material layer.

8. Each of the first charge generation layer and the second charge generation layer has a stacked structure of an n-type charge generation layer and a p-type charge generation layer, The p-type charge generation layer of the second charge generation layer is separated from the p-type charge generation layer of the first charge generation layer. The display device according to claim 1.

9. A first lower electrode located on the first light-emitting region of the element substrate, A second lower electrode located on the second light-emitting region of the element substrate, A light-emitting unit located on the first lower electrode and the second lower electrode and having a stacked structure of a first light-emitting material layer, a charge generation layer, and a second light-emitting material layer, An upper electrode located on the light-emitting unit and overlapping the first light-emitting region and the second light-emitting region, including The charge generation layer of the light-emitting unit has a stacked structure of an n-type charge generation layer and a p-type charge generation layer, The p-type charge generation layer overlapping the second light-emitting region is separated from the p-type charge generation layer overlapping the first light-emitting region, A display device, wherein the content of the p-type dopant in the p-type charge generation layer located on the second light-emitting region is different from the content of the p-type dopant in the p-type charge generation layer located on the first light-emitting region.

10. The p-type dopant contained in the p-type charge generation layer located on the second light-emitting region includes the same substance as the p-type dopant contained in the p-type charge generation layer located on the first light-emitting region. The display device according to claim 9.

11. The light-emitting unit includes an upper hole transport layer located between the charge generation layer and the second light-emitting material layer, The upper hole transport layer overlapping the second light-emitting region is separated from the upper hole transport layer overlapping the first light-emitting region. The content of the p-type dopant in the upper hole transport layer located on the second light-emitting region is different from the content of the p-type dopant in the upper hole transport layer located on the first light-emitting region. The display device according to claim 9.

12. The content of the p-type dopant in the p-type charge generation layer located on the first light-emitting region is lower than the content of the p-type dopant in the p-type charge generation layer located on the second light-emitting region. The content of the p-type dopant in the upper hole transport layer located on the first light-emitting region is lower than the content of the p-type dopant in the upper hole transport layer located on the second light-emitting region. The display device according to claim 11.

13. Further comprising a third lower electrode located on the third light-emitting region of the element substrate. The light-emitting unit and the upper electrode extend on the third lower electrode of the third light-emitting region. The p-type charge generation layer overlapping with the third light-emitting region is separated from the p-type charge generation layer overlapping with the first light-emitting region and the p-type charge generation layer overlapping with the second light-emitting region. The content of the p-type dopant in the p-type charge generation layer located on the third light-emitting region is different from the content of the p-type dopant in the p-type charge generation layer located on the first light-emitting region. The display device according to claim 9.

14. The content of the p-type dopant in the p-type charge generation layer located on the third light-emitting region is different from the content of the p-type dopant in the p-type charge generation layer located on the second light-emitting region. The display device according to claim 13.

15. A first color filter located between the first light-emitting region of the element substrate and the first lower electrode. A second color filter located between the second light-emitting region of the element substrate and the second lower electrode. Further comprising Each of the first light-emitting material layer and the second light-emitting material layer of the light-emitting unit overlaps with the first light-emitting region and the second light-emitting region. The second color filter contains a different material from the first color filter. The display device according to claim 9.

16. The light-emitting unit is provided on the first light-emitting region and the second light-emitting region, and further includes an electron transport layer disposed between a p-type charge generation layer overlapping with the second light-emitting region and a p-type charge generation layer overlapping with the first light-emitting region. The display device according to claim 9.

17. The electron transport layer includes a stepped portion and a planar portion. The stepped portion is on the first light-emitting region and the second light-emitting region, and the planar portion is disposed between the p-type charge generation layer overlapping the second light-emitting region and the p-type charge generation layer overlapping the first light-emitting region. The display device according to claim 16.

18. An element substrate including a first pixel region for displaying blue and a second pixel region for displaying colors other than blue, A first light-emitting element provided on the first pixel region and having a first lower electrode, a first lower hole transport layer, a first lower light-emitting material layer, a first charge generation layer, a first upper light-emitting material layer, and a first upper electrode, A second light-emitting element provided on the second pixel region and having a second lower electrode, a second lower hole transport layer, a second lower light-emitting material layer, a second charge generation layer, a second upper light-emitting material layer, and a second upper electrode, The second lower hole transport layer is spaced apart from the first lower hole transport layer between the first pixel region and the second pixel region A display device in which the content of the p-type dopant in the first lower hole transport layer or the first charge generation layer is different from the content of the p-type dopant in the second lower hole transport layer or the second charge generation layer.

19. The display device according to claim 18, wherein the content of the p-type dopant in the first lower hole transport layer is smaller than the content of the p-type dopant in the second lower hole transport layer.

20. The display device according to claim 18, wherein the content of the p-type dopant in the first charge generation layer is smaller than the content of the p-type dopant in the second charge generation layer.

Images