Trans-reflective OELD Panel with Semi-Reflecting Layer
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Solution Overview
Problem
Conventional organic electroluminescence devices face a trade-off between wide viewing angles and high luminescence output and chromaticity, with non-microcavity devices offering broader viewing angles but lower luminescence and unsaturated chromaticity, while microcavity devices provide better luminescence and chromaticity but at the cost of narrow viewing angles and color shift.
Innovation Solution
A trans-reflective organic electroluminescent panel is designed with a specific proportion of semi-reflecting layer area to transparent electrode area, incorporating a semi-reflecting layer in the light path to enhance luminescence efficiency and color purity within an appropriate viewing angle range, using a multi-layer stack of metallic thin films like silver and aluminum, and adjusting the pattern and position of the semi-reflecting layer to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a microcavity structure with semi-reflecting layer is used, then luminescence output and chromaticity are improved, but viewing angle becomes narrow and color shift occurs
Solution Approach 1:
The device is divided into two separate emission paths: a top-emission path with microcavity structure for high luminescence output and chromaticity, and a bottom-emission path without microcavity for wide viewing angle. The light emitting layer emits light in both directions, with each path optimized independently through selective placement of semi-reflecting and reflective electrodes.
Solution Approach 2:
Different regions of the device have different optical structures optimized for their specific functions. The top electrode region includes semi-reflecting layer for enhanced luminescence output, while the bottom electrode region uses transparent electrode for wide viewing angle. Each region's structure is tailored to its emission requirements.
2Manufacturing precision
If a microcavity structure with semi-reflecting layer is used, then chromaticity is improved, but viewing angle becomes narrow
Solution Approach 1:
The device separates chromaticity optimization from viewing angle optimization into two independent emission paths. The top path with microcavity structure achieves saturated chromaticity through constructive interference, while the bottom path without microcavity maintains wide viewing angle through direct light transmission.
Solution Approach 2:
The semi-reflecting layer is selectively placed only in the top emission path where chromaticity enhancement is needed, while the bottom path maintains simple transparent electrode structure for wide viewing angle. This localized differentiation allows each path to excel at its primary function.
3Adaptability or versatility
If a non-microcavity structure is used, then viewing angle is wide, but luminescence output and chromaticity are inferior
Solution Approach 1:
The device assigns different emission paths to different performance requirements: the bottom path without microcavity structure provides wide viewing angle, while the top path with microcavity structure provides high luminescence output. Both paths work simultaneously to deliver comprehensive performance.
Solution Approach 2:
The dual-emission device merges the advantages of both microcavity and non-microcavity structures into a single device. The top emission provides high brightness and chromaticity, while the bottom emission provides wide viewing angle, combining benefits that were previously mutually exclusive.
4Adaptability or versatility
If a non-microcavity structure is used, then viewing angle is wide, but chromaticity is unsaturated
Solution Approach 1:
The device separates the functions of wide viewing angle and saturated chromaticity into two independent emission paths. The bottom path without semi-reflecting layer maintains wide viewing angle, while the top path with semi-reflecting layer achieves saturated chromaticity through microcavity effect.
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 improved luminescence efficiency and color purity while maintaining an appropriate range of viewing angles, balancing the limitations of both non-microcavity and microcavity devices by optimizing the semi-reflecting layer's proportion and pattern in relation to the transparent electrode.
Implementation Method 1
a semi-reflecting layer disposed in a path of the light
Implementation Method 2
the light emission at a certain range of wavelength is greatly increased, and the light emission at the other range of wavelength is greatly decreased
Implementation Method 3
a light emitting layer formed above the transparent electrode, for generating light toward the transparent electrode
Implementation Method 4
a reflective electrode formed above the light emitting layer
Data Source
AI summary
A trans-reflective organic electroluminescent panel comprises a substrate, several controlling components and displaying regions formed on the substrate. The displaying regions are electrically connected to the controlling components, and each display region has a trans-reflective organic electroluminescent device (OELD). The trans-reflective OELD at least comprises a transparent electrode formed on the substrate, a light emitting layer formed above the transparent electrode, a reflective electrode formed above the light emitting layer and a semi-reflecting layer. Light generated from the light emitting layer emits toward the transparent electrode to form a light path, and the semi-reflecting layer is disposed in the middle of the light path. Also, a proper proportion of the area of the semi-reflecting layer to the area of the transparent electrode is determined for improving the luminescence and color performances of the trans-reflective organic electroluminescent panel.