OLED Resonant Cavity Design for Color Purity and Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic light emitting diodes (OLEDs) face challenges in achieving high color purity and light efficiency due to the difficulty in optimizing the optical length and resonant distances for different wavelengths, leading to shifts in color and reduced light extraction efficiency.
Innovation Solution
The OLED design incorporates a first and second light emitting layer with specific optical lengths and resonant distances, along with a charge generating layer, to control the emission of light, ensuring that the first optical length is optimized for blue light and the second optical length for yellow light, enhancing color purity and light efficiency by controlling the distance between electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the optical length is optimized for one wavelength, then light efficiency is improved for that wavelength, but color purity deteriorates due to shifts in other wavelengths
Solution Approach 1:
The patent divides the light emitting structure into multiple light emitting layers, each optimized for specific wavelength ranges. The first light emitting layer emits blue light (450-495nm), the second emits green light (495-570nm), and the third emits red light (620-750nm). Each layer has its own optimized optical length and resonant distance parameters, allowing independent optimization for light efficiency without compromising overall color purity. This segmentation resolves the contradiction by enabling wavelength-specific optimization.
2Use of energy by moving object
If the optical length is increased to improve light extraction efficiency, then light efficiency is improved, but device complexity increases due to additional layers
Solution Approach 1:
The patent combines multiple light emitting layers with different emission wavelengths into a single integrated OLED structure. The first, second, and third light emitting layers are stacked sequentially between the same pair of electrodes (first electrode layer and second electrode layer), sharing common charge generating layers and transport layers. This merging approach improves light extraction efficiency through cumulative emission while avoiding the complexity of separate devices, as all layers are fabricated in one process sequence.
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 allows for the generation of white light with high purity and improved light efficiency without adding new functional layers or modifying materials, effectively addressing the challenges of color shifts and efficiency in OLEDs.
Implementation Method 1
Holes provided from the anode electrode and electrons provided from the cathode electrode are coupled in the light emitting layer to form excitons and then produce light corresponding to the energy between holes and electrons from the excitons
Implementation Method 2
An optical length between the first and second electrode layers is a fourth resonant distance of the first light
Data Source
AI summary
Provided is an organic light emitting diode including a first electrode layer, a second electrode layer opposing the first electrode layer, a first light emitting layer between the first and second electrode layers to generate a first light having a first wavelength, a second light emitting layer between the first light emitting layer and the second electrode layer to generate a second light having a second wavelength which is longer than the first wavelength, and a charge generating layer between the first and second light emitting layers. The first and second lights are emitted through the second electrode layer. An optical length between the first and second electrode layers is substantially the same as a fourth resonant distance of the first light.