CN-122028608-A - Light-emitting display device

Abstract

The present disclosure relates to a light emitting display device. The light emitting display device includes a first electrode at each of a plurality of sub-pixels on a substrate, a first common layer on the first electrode, an electron blocking layer disposed on the first common layer and at the first sub-pixel of the sub-pixels, a first light emitting layer on the electron blocking layer, the first light emitting layer surrounding the electron blocking layer and having an edge more outward than an edge of the electron blocking layer, a second common layer on the light emitting layer, and a second electrode on the second common layer.

Inventors

• LI ZHAOXI
• JIN YONGZHE

Assignees

• 乐金显示有限公司

Dates

Publication Date

20260512

Application Date

20250930

Priority Date

20241112

Claims (20)

1. 1. A light emitting display device, the light emitting display device comprising: A first electrode on the substrate at each of the plurality of sub-pixels; A first layer of the common-use layer, the first common layer is located on the first electrode, An electron blocking layer on the first common layer, the electron blocking layer at a first subpixel of the plurality of subpixels; a first light emitting layer on the electron blocking layer, the first light emitting layer surrounding the electron blocking layer and having an edge more outward than an edge of the electron blocking layer; a second common layer on the first light emitting layer, and And a second electrode on the second common layer.
2. 2. The light-emitting display device according to claim 1, wherein a bottom surface of the first light-emitting layer disposed further outward than the edge of the electron blocking layer is in contact with the first common layer.
3. 3. The light-emitting display device of claim 1, wherein the electron blocking layer has a HOMO level lower than a HOMO level of a host of the first light-emitting layer, and A first energy level gap between a HOMO energy level of the electron blocking layer and a HOMO energy level of the host of the first light emitting layer is greater than a second energy level gap between a HOMO energy level of the host of the first light emitting layer and a HOMO energy level of the first common layer.
4. 4. The light-emitting display device according to claim 1, further comprising a first hole transport auxiliary layer between the first common layer and the electron blocking layer at the first subpixel.
5. 5. The light-emitting display device according to claim 4, wherein an edge of the first hole-transport auxiliary layer is provided at the same region as an edge of the first light-emitting layer or is provided further inward than the edge of the first light-emitting layer.
6. 6. The light-emitting display device according to claim 5, wherein the edge of the first hole-transport auxiliary layer is provided at the same region as the edge of the electron blocking layer or is provided further outward than the edge of the electron blocking layer.
7. 7. The light-emitting display device according to claim 4, wherein a bottom surface of the first light-emitting layer which is disposed further outward than the edge of the electron blocking layer is in contact with the first hole transport auxiliary layer.
8. 8. The light-emitting display device of claim 7, wherein the electron blocking layer has a HOMO level lower than a HOMO level of a host of the first light-emitting layer, and A first energy level gap between a HOMO energy level of the electron blocking layer and a HOMO energy level of the host of the first light emitting layer is greater than a third energy level gap between a HOMO energy level of the host of the first light emitting layer and a HOMO energy level of the first hole transport auxiliary layer.
9. 9. The light emitting display device of claim 7, wherein a thickness of the first light emitting layer is greater than a thickness of the electron blocking layer.
10. 10. The light-emitting display device of claim 7, wherein the electron blocking layer has a HOMO level lower than a HOMO level of the first hole transport auxiliary layer.
11. 11. The light-emitting display device according to claim 1, wherein the first light-emitting layer has an emission peak at a wavelength of 510nm to 590 nm.
12. 12. The light-emitting display device according to claim 11, further comprising a second light-emitting layer having an emission peak at a wavelength of 600nm to 650nm or a third light-emitting layer having an emission peak at a wavelength of 420nm to 490nm between the first common layer and the second common layer at a second sub-pixel adjacent to the first sub-pixel.
13. 13. The light-emitting display device according to claim 12, further comprising a second hole transport auxiliary layer and an adjacent electron blocking layer between the first common layer and the second light-emitting layer, Wherein each of the second hole transport auxiliary layer and the adjacent electron blocking layer is spaced apart from the first light emitting layer.
14. 14. The light emitting display device of claim 13, wherein the adjacent electron blocking layer is spaced apart from the electron blocking layer.
15. 15. The light-emitting display device according to claim 13, wherein a thickness of the second hole-transport auxiliary layer is greater than a thickness of the first hole-transport auxiliary layer.
16. 16. The light-emitting display device according to claim 1, further comprising a laminate of an adjacent electron blocking layer and a second light-emitting layer between the first common layer and the second common layer at a second sub-pixel adjacent to the first sub-pixel, the second light-emitting layer for emitting light of a different color from the first light-emitting layer.
17. 17. The light emitting display device of claim 16, wherein a HOMO level difference between the second light emitting layer and the adjacent electron blocking layer is less than a HOMO level difference between the first light emitting layer and the electron blocking layer.
18. 18. The light emitting display device of claim 16, further comprising a bank for exposing light emitting portions of the plurality of sub-pixels, Wherein an edge of the first light emitting layer and an edge of the second light emitting layer overlap a top surface of the same bank at different positions.
19. 19. The light emitting display device of claim 16, wherein the electron blocking layer and the adjacent electron blocking layer comprise the same material.
20. 20. The light emitting display device of claim 1, wherein the electron blocking layer has a HOMO level lower than a HOMO level of the first common layer.

Description

Light-emitting display device Cross Reference to Related Applications The present application claims priority or benefit from korean patent application No.10-2024-0160312, filed 11/12 at 2024, which is incorporated herein by reference in its entirety for all purposes as if fully set forth herein. Technical Field The present disclosure relates to a display device, and more particularly, for example, but not limited to, a light emitting display device capable of reducing or preventing degradation of image quality through smooth discharge upon switching to an off state by changing the structure of a light emitting element. Background With the advent of information society, there is an increasing demand for various forms of display devices for displaying images. A light emitting display device including a light emitting element for constituting a pixel does not need a separate light source unit, and thus is advantageous in light weight and slim or flexible, and has excellent color purity. For example, a light emitting element includes two different electrodes and a light emitting layer between the electrodes. In order to improve the light emitting efficiency, as an example, the light emitting element has various functional layers in addition to the light emitting layer between two electrodes, but is not limited thereto. The description provided in the background section should not be assumed to be prior art merely because it was mentioned in or associated with the background section. The background section may include information describing one or more aspects of the subject technology Disclosure of Invention Accordingly, the present disclosure is directed to a light emitting display device that substantially obviates one or more problems due to limitations and disadvantages of the related art. The light emitting display device displays an image while the sub-pixels are repeatedly turned on and off. In order to display light of different colors, a color light-emitting layer that emits light of different colors is used as a light-emitting element. The light emitting layers of different colors comprise different materials. Therefore, the color light emitting layers of different colors exhibit different interface characteristics with adjacent functional layers in different sub-pixels. Carrier accumulation may occur at an interface between a light emitting layer having a large band gap difference and an adjacent functional layer, and discharge may be delayed even after switching to an off state, resulting in defects. An aspect of the present disclosure is to provide a light emitting display device capable of preventing a phenomenon called "smear" in which, when switching to an off state, luminance before the off state is delayed due to discharge delay. Additional advantages, objects, and features of the disclosure will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the disclosure. The objectives and other advantages of the disclosure will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. According to one aspect of the present disclosure, there is provided a light emitting display device including a first electrode at each of a plurality of sub-pixels on a substrate, a first common layer on the first electrode, an electron blocking layer disposed on the first common layer and at a first sub-pixel of the sub-pixels, a first light emitting layer on the electron blocking layer, the first light emitting layer surrounding the electron blocking layer and having an edge more outward than the edge of the electron blocking layer, a second common layer on the light emitting layer, and a second electrode on the second common layer. According to another aspect of the present disclosure, there is provided a light emitting display device including a first electrode on a substrate at each of a first sub-pixel, a second sub-pixel, and a third sub-pixel, a first common layer on the first electrode, the first common layer being on the first sub-pixel to the third sub-pixel, a first electron blocking layer on the first common layer at the first sub-pixel, and a second electron blocking layer disposed on the first common layer at the second sub-pixel and the third sub-pixel, a green light emitting layer on the first electron blocking layer, and a red light emitting layer and a blue light emitting layer on the second sub-pixel and the third sub-pixel, respectively, the second common layer being on the green light emitting layer, the blue light emitting layer, the second electrode, and the second electrode being on the second electrode. It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanator