OLED Micro Cavity Electrode Structure for Light Extraction
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Solution Overview
Problem
Conventional OLEDs suffer from low light extraction efficiency, with only about 20% of the light produced being emitted, leading to increased power consumption and reduced lifetime when attempting to enhance brightness by increasing current.
Innovation Solution
The OLED design incorporates a substrate with sub-pixels featuring a micro cavity effect through a third electrode between the organic light emitting layer and the second electrode, along with an overcoat layer having a groove with an inclined side wall, enhancing light extraction efficiency and color purity by guiding light through both the first and second display regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If current applied to the organic light emitting layer is increased to increase brightness, then brightness is improved, but power consumption increases and lifetime is reduced
Solution Approach 1:
The patent changes the optical parameters of the device by introducing a micro cavity structure with specific reflective layers and cavity depth. This modifies the light extraction efficiency parameter, allowing more light to be extracted from the organic light emitting layer without increasing the input current, thereby resolving the contradiction between brightness and power consumption
Solution Approach 2:
The patent introduces a third electrode as an intermediary element between the organic light emitting layer and the second electrode. This third electrode creates a micro cavity effect that acts as an optical mediator to enhance light extraction efficiency, enabling improved brightness without additional power consumption
2Illumination intensity
If current applied to the organic light emitting layer is increased to increase brightness, then brightness is improved, but lifetime is reduced
Solution Approach 1:
The patent modifies the optical extraction parameter through the micro cavity structure, increasing light extraction efficiency from approximately 20% to higher values. This parameter change allows the OLED to achieve required brightness levels at lower current densities, reducing operational stress and extending device lifetime
Solution Approach 2:
The third electrode serves as an optical intermediary that enhances light extraction through the micro cavity effect. By introducing this intermediary structure, the patent enables efficient light extraction without increasing current, thereby protecting the organic light emitting layer from degradation and extending lifetime
3Ease of manufacture
If conventional OLED structure is used, then manufacturing is simple, but light extraction efficiency is low
Solution Approach 1:
The patent segments the electrode structure by introducing a third electrode between the organic light emitting layer and the second electrode. This segmentation creates distinct functional zones including a micro cavity region and a waveguide region, enabling improved light extraction while maintaining compatibility with conventional manufacturing processes
Solution Approach 2:
The patent applies local quality enhancement by creating a micro cavity structure in specific regions (first display area) while maintaining other regions (second display area) with different characteristics. The reflective layers and cavity depth are optimized locally to maximize light extraction efficiency in critical areas without complicating the overall manufacturing process
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 improves light extraction efficiency, maintains high brightness, and reduces power consumption while minimizing color shift and light leakage, thereby extending the OLED's lifespan.
Implementation Method 1
the first and third electrodes are able to achieve a micro cavity effect
Implementation Method 2
When a transition of the exciton from an excited state to a ground state occurs, a light is produced and emitted from the EML 40
Implementation Method 3
an overcoat layer having a groove with an inclined side wall, enhancing light extraction efficiency and color purity by guiding light through both the first and second display regions
Data Source
AI summary
An organic light emitting diode display (OLED) is disclosed. The disclosed OLED includes a substrate including a plurality of sub-pixels, each sub-pixel comprising a display area and a non-display area surrounding the display area, the display area comprising a first display area at a center region of the display area and a second display area surrounding the first display area; a first electrode formed in the display area; an organic light emitting layer formed on the first electrode and extending to the non-display area; a third electrode formed on a portion of the organic light emitting layer in the first display area; and a second electrode formed on the third electrode and the organic light emitting layer, wherein the first and third electrodes are able to achieve a micro cavity effect.