OLED Subpixel Units with Transflective Electrodes
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Solution Overview
Problem
Organic light emitting devices (OLEDs) often fail to achieve desired optical characteristics such as wavelength and color purity due to material variations and light interference, limiting the range of colors that can be displayed.
Innovation Solution
The OLED device incorporates multiple subpixel units with different color characteristics and multi-layered thin film structures, including transflective electrodes, to expand the range of colors perceived by the human eye, allowing for a broader gamut of colors to be displayed by varying the number and structure of thin films in each subpixel unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional RGB-only configurations with single subpixel units are used, then device complexity is low, but the range of colors that can be displayed is limited
Solution Approach 1:
The patent divides each pixel into multiple subpixel units (first and second subpixel units) with different color characteristics. Each subpixel unit has its own organic light emitting member with distinct emission spectra, allowing the device to display a broader color gamut by combining outputs from multiple subpixels with different color coordinates on the CIE chromaticity diagram.
Solution Approach 2:
The patent implements different multi-layered thin film structures in different subpixel units to achieve locally optimized optical characteristics. Each subpixel unit has tailored thin film compositions and thicknesses to produce specific color characteristics, with transflective electrodes strategically placed to enhance light extraction efficiency for particular color ranges.
2Manufacturing precision
If material variations in organic light emitting elements are present, then manufacturing is simplified, but optical characteristics such as wavelength and color purity deteriorate
Solution Approach 1:
The patent compensates for material variations by adjusting thin film thickness parameters and compositional ratios in the multi-layered structure. By optimizing the thickness of each layer and the ratio of organic materials, the device achieves consistent color purity and wavelength characteristics despite variations in organic light emitting material properties during manufacturing.
Solution Approach 2:
The patent uses composite multi-layered thin film structures combining different inorganic and organic materials with complementary properties. This composite approach allows the device to achieve desired optical characteristics by leveraging the strengths of different materials while compensating for their individual limitations and variations.
3Manufacturing precision
If light interference by thin films is present, then device structure is simplified, but optical characteristics such as bandwidth and color purity deteriorate
Solution Approach 1:
The patent converts the harmful effect of light interference by thin films into a beneficial effect by strategically designing the multi-layered thin film structure. The interference patterns are harnessed to enhance light extraction efficiency and modify emission spectra, improving color purity and bandwidth while maintaining a relatively simple overall device structure.
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 increases the range of colors that can be displayed by approximately 40% to 70% compared to conventional RGB-only configurations, enhancing the perceived luminosity and chrominance by allowing independent control of subpixels with different emission spectra.
Implementation Method 1
The composition of each organic light emitting member is such that when activated it emits light corresponding to one of three colors such as the three primary colors red, green, and blue, or it emits white light
Implementation Method 2
the first subpixel unit has a transflective electrode whereas the second subpixel unit does not
Implementation Method 3
light interference by a thin film through which the unit generated light passes
Data Source
AI summary
An organic light emitting device includes a first pixel displaying a first color, a second pixel adjacent to the first pixel and displaying a second color, and a third pixel adjacent to the first pixel or the second pixel and displaying a third color, wherein the first pixel includes a first and second subpixel units that output respective lights having different color characteristics.