CN-116344700-B - Top-emission electroluminescent display

Abstract

The present disclosure relates to a top emission type electroluminescent display in which a portion of a gap between an anode electrode and a cathode electrode is formed to be narrow. An electroluminescent display according to the present disclosure includes a pixel on a substrate, a light emitting element in the pixel, the light emitting element including a first electrode, an emission layer on the first electrode, and a second electrode on the emission layer, and a light shielding layer under the emission layer, with a planarization layer between the emission layer and the light shielding layer, the light shielding layer overlapping a first portion of the emission layer. A first distance is formed between the first electrode and the second electrode at the first portion. A second distance is formed between the first electrode and the second electrode at a second portion of the emissive layer different from the first portion, the first distance being less than the second distance.

Inventors

• SHEN CHENGBIN

Assignees

• 乐金显示有限公司

Dates

Publication Date

20260512

Application Date

20221215

Priority Date

20211227

Claims (11)

1. 1. An electroluminescent display comprising: Pixels on a substrate; a light emitting element in the pixel, the light emitting element including a first electrode, an emission layer on the first electrode, and a second electrode on the emission layer, and A light shielding layer below the emission layer, and a planarization layer is provided between the light shielding layer and the emission layer, the light shielding layer overlapping with a first portion of the emission layer, Wherein a first distance is formed between the first electrode and the second electrode at the first portion, Wherein a second distance is formed between the first electrode and the second electrode at a second portion of the emission layer different from the first portion, and Wherein the first distance is made smaller than the second distance by applying thermal energy to the light shielding layer to expand the first electrode above the light shielding layer toward the second electrode in a region corresponding to the first portion of the emission layer.
2. 2. The electroluminescent display of claim 1 further comprising: A driving element connected to the light emitting element and disposed below the planarizing layer, the driving element overlapping the light shielding layer, and a buffer layer disposed between the driving element and the light shielding layer.
3. 3. The electroluminescent display of claim 2 wherein the drive element comprises a thin film transistor having: A semiconductor layer; A gate electrode overlapping with a middle portion of the semiconductor layer; a source electrode connected to one side of the semiconductor layer, and A drain electrode connected to the other side of the semiconductor layer, Wherein the light shielding layer overlaps the semiconductor layer, and the buffer layer is provided between the light shielding layer and the semiconductor layer.
4. 4. The electroluminescent display of claim 3 wherein the driving element further comprises: and a storage capacitor overlapping the first electrode and connected to the thin film transistor.
5. 5. The electroluminescent display of claim 4 wherein the light shielding layer overlaps the storage capacitor.
6. 6. The electroluminescent display of claim 1 wherein the first portion of the emissive layer overlapping the light shielding layer is in the range of 40% to 70% of the entire area of the light emitting element.
7. 7. An electroluminescent display comprising: Pixels on a substrate; a light emitting element in the pixel, the light emitting element including a first electrode, an emission layer on the first electrode, and a second electrode on the emission layer, and A light shielding layer below the emission layer with a planarization layer therebetween, the light shielding layer overlapping a portion of the emission layer, Wherein a first portion of the emission layer not overlapping the light shielding layer has a first thickness, Wherein a second portion of the emission layer overlapping the light shielding layer has a second thickness, and Wherein the second thickness is made thinner than the first thickness by applying thermal energy to the light shielding layer to expand the first electrode over the light shielding layer toward the second electrode in a region corresponding to the second portion of the emission layer.
8. 8. The electroluminescent display of claim 7 further comprising: A driving element connected to the light emitting element and disposed below the planarizing layer, the driving element overlapping the light shielding layer, and a buffer layer disposed between the driving element and the light shielding layer.
9. 9. The electroluminescent display of claim 7 wherein the second portion of the emissive layer overlapping the light shielding layer is in the range of 40% to 70% of the entire area of the light emitting element.
10. 10. A method for manufacturing an electroluminescent display, comprising: Forming a light shielding layer on a substrate; Depositing a buffer layer on the entire surface of the substrate to cover the light shielding layer; Forming a driving element overlapping a portion of the light shielding layer on the buffer layer; Depositing a planarization layer on the entire surface of the substrate to cover the driving element; forming a light emitting element including a first electrode, an emission layer, and a second electrode on the planarization layer and overlapping the light shielding layer, and Heat energy is applied to the light shielding layer such that the first electrode above the light shielding layer expands toward the second electrode and a gap between the first electrode and the second electrode is reduced in a region corresponding to a portion of the emission layer overlapping the light shielding layer.
11. 11. An electroluminescent display comprising: A plurality of pixels on the substrate, each of the plurality of pixels including a light emitting element, wherein the light emitting element includes a first electrode, an emission layer on the first electrode, and a second electrode on the emission layer, and A light shielding layer under the light emitting element of each pixel, Wherein the light shielding layer is applied with heat energy such that a portion of the first electrode above the light shielding layer expands toward the second electrode, and a thickness of a portion of the emission layer between the expanded portion of the first electrode and the second electrode is reduced.

Description

Top-emission electroluminescent display Cross Reference to Related Applications The present application claims the benefit of korean patent application No. 10-2021-0188517, filed on month 27 of 2021, 12, which is hereby incorporated by reference as if fully set forth herein. Technical Field The present disclosure relates to top emission electroluminescent displays. . Background Recently, various types of displays have been developed, such as Cathode Ray Tubes (CRTs), liquid Crystal Displays (LCDs), plasma Display Panels (PDPs), and electroluminescent displays. These types of displays are used to display image data of various products, such as computers, mobile phones, bank deposit and withdrawal devices (ATM) and car navigation systems, according to their unique characteristics and uses. In particular, electroluminescent displays, which are self-luminous displays, have excellent optical properties such as viewing angle and color realization, so that their application fields are gradually widened, and are attracting attention as image display devices. Because of these advantages, electroluminescent displays are attracting attention as the most suitable displays for realizing 4K ultra-high resolution display and up to 8K ultra-high resolution display. As the resolution increases, the size of the pixel becomes smaller, and the size of the light emitting region occupied in the pixel also becomes smaller. As the size of the pixels in an electroluminescent display becomes smaller, a top emission type structure is preferably applied to maximize the size ratio of the light emitting regions in the pixels. As the resolution increases, the size of the pixel decreases. In order to drive the light emitting element in a smaller pixel, it is necessary to reduce driving power consumption. However, since it is very difficult to form a narrow distance between an anode electrode and a cathode electrode included in a light emitting diode provided in a pixel, there is a limit in reducing driving power. Even if the existing manufacturing process is used as it is, it is necessary to develop an electroluminescent display having a new structure capable of reducing driving power by realizing a narrowed distance between an anode electrode and a cathode electrode. Disclosure of Invention With respect to solving the above-described problems, an object of the present disclosure is to provide an electroluminescent display having a structure that reduces driving power consumption by forming a narrow distance (or gap) between an anode electrode and a cathode electrode. It is another object of the present invention to provide an electroluminescent display with lower overall driving power consumption, which applies thermal energy to partially narrow the distance between an anode and a cathode after forming a light emitting diode having a distance between the anode and the cathode using an existing manufacturing process. According to the present disclosure, in the top emission type electroluminescent display, by applying thermal energy to the metal layer disposed under the light emitting element, a portion of the gap between the anode electrode and the cathode electrode can be narrowed. In order to achieve at least one of the above objects of the present disclosure, an electroluminescent display according to the present disclosure includes a pixel on a substrate, a light emitting element in the pixel, the light emitting element including a first electrode, an emission layer on the first electrode, and a second electrode on the emission layer, a light shielding layer under the emission layer, and a planarization layer disposed between the emission layer and the light shielding layer, the light shielding layer overlapping with a first portion of the emission layer. A first distance is formed between the first electrode and the second electrode at the first portion. A second distance is formed between the first electrode and the second electrode at a second portion of the emissive layer different from the first portion, the first distance being less than the second distance. In one embodiment, the electroluminescent display further comprises a driving element connected to the light emitting element and disposed below the planarization layer, the driving element overlapping the light shielding layer, and a buffer layer disposed between the light shielding layer and the driving element. In one embodiment, the driving element includes a thin film transistor having a semiconductor layer, a gate electrode overlapping a middle portion of the semiconductor layer, a source electrode connected to one side of the semiconductor layer, and a drain electrode connected to the other side of the semiconductor layer. The light shielding layer overlaps the semiconductor layer, and a buffer layer is provided between the light shielding layer and the semiconductor layer. In one embodiment, the driving element further includes a storage capacitor overlapping the fir