Serially Connected OELD Color-Shift Compensation
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Solution Overview
Problem
Conventional organic electroluminescent devices (OELDs) using a white electroluminescent material and color filter struggle with color purity and consistency, leading to impure white light emission due to color-shift issues when varying electrical potentials are applied, which complicates achieving high resolution and clear contrast in full-color displays.
Innovation Solution
A method for improving color-shift in serially connected OELDs by determining and combining OELD units with different color-shift tendencies, using a connecting layer to compensate for these tendencies, thereby achieving a substantially pure light color emission across varying electrical potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a white electroluminescent material and color filter are used to achieve full-color emission, then the fabrication process is simplified, but color purity and luminance efficiency deteriorate due to color-shift issues
Solution Approach 1:
The patent divides the white light OELD into multiple serially connected color conversion units, each containing a blue electroluminescent material and a color conversion material. This segmentation allows each unit to emit a specific color (cyan, yellow, magenta) with high purity, and combines them to achieve full-color emission without the color-shift problems of conventional white light OELDs.
Solution Approach 2:
The patent applies different color conversion materials in different local regions (first, second, and third color conversion materials converting blue light to cyan, yellow, and magenta respectively). Each local region has optimized properties for its specific color conversion function, allowing precise control over the emitted light spectrum and eliminating the need for external color filters.
2Adaptability or versatility
If conventional white light OELD with color filter is used, then full-color emission is achieved, but color consistency deteriorates when electrical potential varies
Solution Approach 1:
The patent changes the fundamental parameter of light emission by using multiple electroluminescent materials with different emission characteristics (blue electroluminescent material combined with color conversion materials) instead of relying on a single white electroluminescent material with a color filter. This parameter change ensures that color emission remains consistent across varying electrical potentials.
3Use of energy by moving object
If RGB side-by-side method is used to achieve full-color emission, then optimal light efficiency is achieved, but device complexity increases due to shadow-masks and alignment requirements
Solution Approach 1:
The patent merges the advantages of the RGB side-by-side method (high luminance efficiency) with the simplicity of the white light OELD method by using a single electroluminescent layer structure that intrinsically produces full-color emission through serially connected color conversion units, eliminating the need for shadow-masks and complex alignment procedures.
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
The method enables the production of OELDs that emit pure or almost pure white light, with improved color balance and reduced color shift, simplifying the fabrication process and increasing production yield by eliminating the need for precise alignment and complex shadow-masks.
Implementation Method 1
The material of the organic light emitting layer 15 is able to emit light when excited by electric current
Data Source
AI summary
A serially connected organic electroluminescence device (SC-OELD) comprises the first OELD unit, the second OELD unit and a connecting layer disposed between the first OELD unit and second OELD unit. A method for improving color-shift of the SC-OELD, comprises: determining the color-shift tendencies of the first OELD unit and the second OELD unit, respectively, according to the different currents passing through the first OELD unit and second OELD unit; and combining the first OELD unit and the second OELD unit with the different color-shift tendencies, whereby the different color-shift tendencies of the first OELD unit and the second OELD unit are compensated each other while the electric charge is applied to the SC-OLED, so as to obtain a substantially pure color of the SC-OELD.