OLED Pixel Area Variation for Lifetime Uniformity
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Solution Overview
Problem
Conventional OLEDs have non-uniform lifetimes for their red, green, and blue light emitting layers, leading to reduced overall device lifetime due to differences in luminance and current density across these layers.
Innovation Solution
The solution involves forming OLEDs with light emitting portions of different areas for each color, where the areas are determined by reference lifetimes, ensuring uniform current distribution and luminance, thereby extending the device's operational lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional OLEDs use uniform light emitting layers for red, green, and blue colors, then the device structure is simple and easy to manufacture, but the lifetimes of different color layers are non-uniform leading to reduced overall device lifetime
Solution Approach 1:
The patent applies local quality by making the light emitting portions of different colors have different areas rather than uniform dimensions. Specifically, the red, green, and blue light emitting portions are designed with varying sizes to compensate for their different inherent lifetimes, ensuring that each color contributes equally to the overall device lifetime. This localized variation in geometry resolves the contradiction between reliability and structural simplicity.
Solution Approach 2:
The patent changes the geometric parameter (area) of the light emitting portions to optimize device lifetime. By adjusting the areas of red, green, and blue light emitting portions based on their reference lifetimes, the invention transforms a uniform structure into a non-uniform one where each portion's area is specifically tailored to achieve uniform current distribution and extend overall device lifetime.
2Reliability
If light emitting portions have different areas to compensate for lifetime differences, then uniform current distribution and extended lifetime are achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-determining the areas of light emitting portions based on reference lifetimes before the actual manufacturing process. The areas are designed in advance to compensate for known lifetime differences of different color materials, allowing manufacturers to follow a predetermined pattern rather than requiring complex real-time adjustments during fabrication.
Solution Approach 2:
The patent employs inkjet printing technology to deposit organic light emitting materials with precise area control. The inkjet printing process enables accurate placement of materials in predetermined patterns, achieving the required manufacturing precision for different sized light emitting portions through controlled material deposition rather than requiring complex mechanical alignment.
3Productivity
If uniform areas are used for all light emitting portions, then manufacturing is easier and faster, but current distribution becomes non-uniform reducing device performance
Solution Approach 1:
The patent applies local quality by designing different areas for red, green, and blue light emitting portions according to their specific lifetime characteristics. This localized differentiation ensures that each color portion receives appropriate current distribution, preventing overheating and degradation in any single region, thereby maintaining both manufacturing efficiency and device reliability.
Solution Approach 2:
The patent changes the area parameter of light emitting portions to optimize current distribution. By adjusting areas based on reference lifetimes, the invention ensures that current density is balanced across different colors, preventing localized overheating and extending overall device lifetime while maintaining a relatively simple 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 approach results in a display device with improved uniformity and extended lifetime by optimizing the areas of red, green, and blue light emitting portions based on their reference lifetimes, enhancing the overall performance and longevity of the OLED.
Implementation Method 1
A red light emitting portion, a green light emitting portion and a blue light emitting portion are formed on the first electrodes, respectively
Data Source
AI summary
A display device for increasing a lifetime includes a base substrate having a plurality of pixel regions, a plurality of first electrodes formed on the pixel regions, a light emitting layer including first, second and third light emitting portions to generate first, second and third lights, a second electrode that is electrically coupled to the light emitting layer. At least two of the first, second and third light emitting portions have different areas from each other. The areas of the light emitting portions are determined by reference lifetimes. Therefore, the lifetime for the display device is increased.