Transparent Electrode Roughness in Microcavity Light-Emitting Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The emission efficiency of light-emitting devices with microcavity structures is not consistently improved, even when using high reflectivity materials for reflective electrodes, due to variations in light-emitting element performance.
Innovation Solution
The use of polycrystalline conductive oxides for transparent electrodes in light-emitting elements where light is amplified and emitted, and amorphous conductive oxides for other elements, along with varying transparent electrode thicknesses, to optimize surface roughness and optical adjustment for enhanced emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high reflectivity materials are used for reflective electrodes, then emission efficiency should be improved, but emission efficiency is not consistently improved across all light-emitting elements due to performance variations
Solution Approach 1:
The patent applies different surface roughness characteristics to transparent electrodes in different light-emitting elements. Specifically, the transparent electrode in the first light-emitting element has a different surface roughness than those in other elements, allowing optimization for that specific element's performance while maintaining consistency across the device array.
Solution Approach 2:
The patent changes the surface roughness parameter of transparent electrodes to optimize emission efficiency. By adjusting this physical parameter locally in specific light-emitting elements, the patent achieves consistent high emission efficiency across all elements while using the same high reflectivity material for reflective electrodes.
2Illumination intensity
If transparent electrode thickness is varied to optimize optical adjustment for different colors, then light amplification is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements different transparent electrode thicknesses in different light-emitting elements to optimize optical adjustment for specific colors. This local variation in thickness allows each element to be optimized for its intended wavelength while using a standardized manufacturing process framework.
Solution Approach 2:
The patent segments the transparent electrode layer into different thickness regions corresponding to different light-emitting elements. This segmentation allows independent optimization of optical properties for each color channel (red, green, blue) while maintaining a unified device structure.
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 approach improves the emission efficiency of light-emitting devices by selectively enhancing light amplification and emission for specific colors, balancing efficiency across different light-emitting elements.
Implementation Method 1
An optical length L between the reflective electrode 501 serving as a reflecting mirror and the semi-transmissive and semi-reflective electrode 507 is adjusted so that light emitted from the EL layer 506 is repeatedly reflected between the reflective electrode 501 and the semi-transmissive and semi-reflective electrode 507; thus, light with a specific wavelength can be selectively amplified and emitted outside.
Implementation Method 2
a reflective electrode, an EL layer, and a semi-transmissive and semi-reflective electrode are formed in that order from the substrate side... light with a specific wavelength can be selectively amplified and emitted outside
Data Source
AI summary
The emission efficiency of a light-emitting device including a microcavity structure is improved. The light-emitting device includes a plurality of light-emitting elements. The plurality of light-emitting elements each include a reflective electrode, a transparent electrode, a plurality of light-emitting layers, and a semi-transmissive and semi-reflective electrode stacked in that order. The plurality of light-emitting layers emit light of different colors. A surface roughness of the transparent electrode in the light-emitting element which is among the plurality of light-emitting elements and in which light emitted from the light-emitting layer closest to the reflective electrode is amplified and emitted outside is greater than surface roughnesses of the transparent electrodes in the other light-emitting elements.