Tand OLED Microcavity for Color Shift and Intensity
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Solution Overview
Problem
Conventional tandem organic electroluminescent apparatuses suffer from low color temperature and significant color shift at large viewing angles due to inadequate emission intensity and spectral characteristics, particularly in white light emission.
Innovation Solution
A tandem organic electroluminescent apparatus is designed with a reflective electrode, a first light emitting unit, a semi-transparent connecting layer, and at least one second light emitting unit, where the semi-transparent connecting layer and reflective electrode form a microcavity to enhance emission intensity and maintain true color temperature without increasing apparatus thickness or driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional tandem organic electroluminescent apparatuses are used to increase emission intensity, then the luminous intensity improves, but the color temperature decreases and color shift increases at large viewing angles
Solution Approach 1:
The apparatus is divided into multiple light emitting units (first and second light emitting units) with different emission characteristics. The first light emitting unit emits blue light while the second emits yellow light, allowing independent optimization of each unit's contribution to the overall spectral composition. This segmentation enables the blue unit to provide high intensity while the yellow unit adjusts the color temperature, resolving the contradiction between intensity and color temperature maintenance.
Solution Approach 2:
Different regions of the apparatus have specialized functions: the first light emitting unit is optimized for high intensity blue emission, while the second light emitting unit is optimized for yellow emission to adjust color temperature. The microcavity structure is specifically positioned between the semi-transparent connecting layer and reflective electrode to enhance the emission of the first light emitting unit, creating local optical enhancement where needed most.
2Illumination intensity
If conventional tandem organic electroluminescent apparatuses are used to increase emission intensity, then the luminous intensity improves, but significant color shift occurs at large viewing angles
Solution Approach 1:
By segmenting the emission into distinct blue and yellow components from separate light emitting units, each unit can be optimized for its specific wavelength range. The blue unit provides intensity while the yellow unit compensates for color shift, maintaining color stability across viewing angles even as total intensity increases.
Solution Approach 2:
The apparatus uses asymmetric layer design where the first light emitting unit (blue) and second light emitting unit (yellow) have different structural configurations optimized for their respective wavelengths. This asymmetric design, combined with the microcavity, creates directional emission control that reduces viewing angle dependence and color shift.
3Illumination intensity
If the microcavity structure is formed between the semi-transparent connecting layer and reflective electrode, then emission intensity increases, but the apparatus thickness increases
Solution Approach 1:
The microcavity structure is nested within the existing tandem apparatus architecture, utilizing the space between the semi-transparent connecting layer and reflective electrode that already exists in the multi-layer structure. This nested approach integrates the optical enhancement function without requiring additional external spacing, minimizing thickness increase while achieving emission intensity enhancement through the cavity resonance effect.
4Illumination intensity
If the microcavity structure is formed between the semi-transparent connecting layer and reflective electrode, then emission intensity increases, but the driving voltage increases
Solution Approach 1:
The segmentation into multiple light emitting units with different emission characteristics allows the first unit to benefit from microcavity enhancement for increased intensity, while the second unit provides color balancing. This segmentation enables targeted optical enhancement without requiring proportional increases in driving voltage across the entire apparatus, as each unit can be independently optimized for its emission function.
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 solution achieves increased emission intensity and reduced color shift at large viewing angles, providing a white light with a higher color temperature closer to true white, enhancing display quality.
Implementation Method 1
the semi-transparent connecting layer and the reflective electrode form a microcavity
Data Source
AI summary
The present application discloses a tandem organic electroluminescent apparatus including a reflective electrode; a first light emitting unit on the reflective electrode; a semi-transparent connecting layer on a side of the first light emitting unit distal to the reflective electrode; at least one second light emitting unit on a side of the semi-transparent connecting layer distal to the first light emitting unit; and a transparent electrode on a side of the at least one second light emitting unit distal to the semi-transparent connecting layer. The semi-transparent connecting layer and the reflective electrode form a microcavity.