Top-Emitting OLED Reflective Layer Repositioning
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Solution Overview
Problem
Conventional top-emitting organic electroluminescent displays face impedance issues due to reflective layer oxidation, leading to reduced light emitting efficiency and chromaticity, as the reflective layer is adjacent to the transparent electrode layer, causing increased resistance and inefficient light routing.
Innovation Solution
The position of the reflective layer is adjusted under the dielectric layer, and the thickness of the dielectric layer is varied to prevent metal oxide formation and create a microcavity effect, reducing resistance and enhancing light emitting efficiency and chromaticity by controlling light routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reflective layer is disposed adjacent to the transparent electrode layer in a conventional top-emitting OLED, then the structure is simpler, but the resistance increases and light emitting efficiency decreases due to metal oxide formation
Solution Approach 1:
The reflective layer is repositioned from a horizontal adjacency to the transparent electrode layer to a vertical configuration beneath the dielectric layer. This spatial rearrangement in the vertical dimension eliminates direct contact between the reflective layer and transparent electrode layer, preventing metal oxide formation while maintaining structural functionality.
Solution Approach 2:
The dielectric layer is introduced as an intermediary component between the reflective layer and the transparent electrode layer. This intermediate layer physically separates the two conductive layers, preventing direct electrical contact and subsequent oxidation reactions, thereby reducing resistance and improving light emitting efficiency.
2Ease of manufacture
If the reflective layer is adjacent to the transparent electrode layer, then manufacturing is easier, but chromaticity is reduced due to inefficient light routing
Solution Approach 1:
The light routing path is optimized by repositioning the reflective layer in the vertical dimension beneath the dielectric layer. This configuration creates an optimized optical path that enhances light extraction efficiency and improves chromaticity, while the planar manufacturing process remains straightforward.
Solution Approach 2:
The thickness of the dielectric layer is optimized to enhance the microcavity effect, which improves light routing and chromaticity. By adjusting this physical parameter, the optical performance is enhanced without complicating the manufacturing process.
3Reliability
If the reflective layer is repositioned under the dielectric layer, then resistance is reduced and light emitting efficiency is enhanced, but the device structure becomes more complex
Solution Approach 1:
The dielectric layer is designed to serve multiple functions: it acts as an insulating layer, a structural support, and an optical microcavity element. By integrating these multiple functions into a single layer, the structure achieves improved light emitting efficiency without proportionally increasing overall device complexity.
Solution Approach 2:
The reflective layer and dielectric layer are combined in a vertically stacked configuration where the dielectric layer simultaneously provides electrical insulation and optical enhancement. This merging of functions reduces the need for additional separate components, balancing structural complexity with performance improvement.
4Illumination intensity
If the dielectric layer thickness is optimized for microcavity effect, then chromaticity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The dielectric layer thickness is optimized within a specific range to achieve the microcavity effect and enhance chromaticity. By defining an optimal thickness range rather than a single precise value, the design balances optical performance improvement with practical manufacturing capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces resistance, enhances light emitting efficiency, and improves chromaticity by preventing metal oxide formation and utilizing the microcavity effect in the dielectric layer to optimize light emission.
Implementation Method 1
the dielectric layer has different thicknesses at the sub-pixel areas of different colors... utilizing the microcavity effect in the dielectric layer to optimize light emission
Implementation Method 2
A reflective layer is disposed on the sub-pixel areas of the substrate... enhances light emitting efficiency and chromaticity by adjusting the thickness of the dielectric layer
Implementation Method 3
The light emitting principle of organic electroluminescent displays, also known as organic light emitting diode (OLED), is to apply an electric field to an organic molecule material to produce luminescence
Data Source
AI summary
The invention provides a top emitting organic electroluminescent display comprising a substrate including a display area. A conductive layer is disposed on the substrate, electrically connecting the substrate. A reflective layer is disposed on the display region of the substrate. A dielectric layer is formed on the conductive layer, the reflective layer and the substrate, with a via exposing the conductive layer. A transparent electrode layer is disposed on the dielectric layer, electrically connecting the conductive layer through the via. An organic electroluminescent layer corresponding to the display region is disposed on the transparent electrode layer.