Display Cathode Thickness Design for Micro-Cavity Light Extraction
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Solution Overview
Problem
As display devices become thinner, the efficiency of light emission decreases due to resonance-based micro-cavity effects, leading to deteriorated light emitting efficiency and viewing angle characteristics.
Innovation Solution
A display device design with varying thicknesses of cathode electrodes and organic material layers in subpixels, optimized to enhance light extraction efficiency while maintaining wide viewing angles, using indium tin oxide (ITO) and indium zinc oxide (IZO) for transparent auxiliary cathode electrodes and organic material layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of the light emitting element layer is decreased to make the display device thinner, then the viewing angle is widened and viewing angle luminance is improved, but the light extraction efficiency deteriorates due to micro-cavity resonance effects
Solution Approach 1:
The light emitting element layer is divided into multiple sublayers (first light emitting sublayer, second light emitting sublayer, third light emitting sublayer) with different thicknesses and light emitting characteristics. This segmentation allows each sublayer to contribute differently to light emission, optimizing both thinness and light extraction efficiency by preventing uniform micro-cavity resonance across the entire layer.
2Length of stationary object
If the thickness of the light emitting element layer is decreased to make the display device thinner, then the viewing angle is widened, but the overall light emitting efficiency deteriorates
Solution Approach 1:
Different regions of the light emitting element layer are assigned different thicknesses and material compositions. The first light emitting sublayer has different characteristics from the second and third sublayers, creating local variations in light emission properties. This allows optimization of light extraction in specific regions while maintaining overall thinness and viewing angle characteristics.
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
Enhances light efficiency and maintains viewing angle characteristics by optimizing cathode thickness and layer configurations, improving light extraction and reducing power consumption.
Implementation Method 1
a light emitting layer, and a cathode electrode that are sequentially stacked
Implementation Method 2
the efficiency of extracting the light emitted from the inside of the thinner light emitting element layer to the outside of the light emitting element layer can decrease due to resonance based on micro-cavity
Data Source
AI summary
A display device can include a substrate including a plurality of data lines, a plurality of gate lines, and a plurality of subpixels arranged in a display area of the display panel; a planarization layer on the plurality of data lines, the plurality of gate lines, and the plurality of subpixels. Each subpixel includes an anode electrode, a light emitting layer, and a cathode electrode that are sequentially stacked, one of an auxiliary cathode electrode and an organic material layer on the cathode electrode, and a capping layer on the one of the auxiliary cathode electrode and the organic material layer on the cathode electrode.