OLED Panel Broadened Color Spectrum via Segmented Pixel Design
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Solution Overview
Problem
Existing organic light-emitting display panels face challenges in achieving improved color properties and spectral width without compromising the lifespan and efficiency of the OLEDs, as the thickness of the cathode layer affects the color spectrum and light-emitting efficiency.
Innovation Solution
The implementation of multiple pixel segments within each color sub-pixel, where each segment has a different resonant cavity length achieved by varying the thickness of specific organic layers, such as the hole injection layer, results in a broader color spectrum by combining light beams of slightly different colors, thereby enhancing the spectral width without significantly impacting the OLED's lifespan or efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the thickness of the cathode layer is increased to improve light-emitting efficiency, then the light-emitting efficiency is improved, but the color spectrum becomes narrower
Solution Approach 1:
The pixel is divided into multiple pixel segments (first pixel segment and second pixel segment), each with different organic layer thicknesses. The first pixel segment has a first organic layer thickness and emits light with a first color spectrum, while the second pixel segment has a second organic layer thickness and emits light with a second color spectrum. By combining these segmented emissions, the overall color spectrum width is broadened while maintaining efficient light emission from each segment.
Solution Approach 2:
Different regions of the pixel (different pixel segments) are given different local properties by varying the organic layer thickness in each segment. This allows each segment to optimize for its specific emission characteristics, with some segments having thicker layers for efficiency and others having thinner layers for spectral broadening, and combining them to achieve both goals simultaneously.
2Adaptability or versatility
If the thickness of the organic layer is varied to broaden the color spectrum, then the spectral width is improved, but the manufacturing precision becomes more difficult
Solution Approach 1:
Instead of attempting to manufacture a single pixel with a complex variable thickness profile, the pixel is segmented into discrete regions with distinct thicknesses. This segmentation simplifies the manufacturing process by allowing each segment to be fabricated with standard thickness control techniques, while the combination of segments achieves the desired spectral broadening effect.
Solution Approach 2:
Multiple pixel segments with different organic layer thicknesses are combined within a single pixel structure. The first pixel segment and second pixel segment are merged to form a complete pixel that benefits from both thickness variations, achieving broadened color spectrum without requiring each individual layer to be manufactured with extreme precision.
3Adaptability or versatility
If multiple pixel segments with different organic layer thicknesses are combined, then the color spectrum is broadened, but the device complexity increases
Solution Approach 1:
The pixel is segmented into multiple functional regions (pixel segments) that can be independently defined and manufactured. Each segment has a specific organic layer thickness optimized for its emission characteristics, and the segments are arranged in a systematic pattern that achieves spectral broadening without creating excessive structural complexity.
Solution Approach 2:
The pixel structure is designed to serve multiple functions simultaneously: each pixel segment generates light emission while the combination of segments broadens the overall color spectrum. The same basic pixel structure can be used across the display panel, with the multi-functionality achieved through the segmented architecture rather than requiring entirely different structures for different functions.
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 allows for a broader color spectrum with reduced color shift sensitivity to manufacturing non-uniformities, improving color properties while maintaining the OLED's performance and lifespan.
Implementation Method 1
An organic light-emitting diode (OLED) is an organic electroluminescent device having a plurality of organic layers disposed between a cathode layer and an anode layer
Implementation Method 2
The thickness of the organic layer section L, serves as a resonant cavity in an OLED
Data Source
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Figure 5~6a
AI summary
A method and device in which the light emitted from a color sub-pixel in an organic light emitted display panel can be the sum of two or more light beams of slightly different colors in the same wavelength range. The difference in color is the result of difference in the length of the resonant cavity within the same color sub-pixel. In the manufacturing process, the non-uniformity in the layer thickness can cause a shift in the color coordinates in the color sub-pixels. The color shift when the width of the color spectrum is narrow is more noticeable. By broadening the width of the color spectrum, the color shift would become less appreciable. Thus, broadening the width of the color spectrum would ease the strict requirements in manufacturing.