Top Emission OLED Black Matrix Reduces Color Shift
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Solution Overview
Problem
The top emission type organic electro luminescence devices face issues with color shift due to light reflection from the first electrode and reduced optical efficiency caused by the use of polarization films, which increases manufacturing costs.
Innovation Solution
A top emission type organic electro luminescence device is designed with a black matrix formed below the first electrode or using a first electrode made of metal with low reflectivity, such as chrome, to minimize light reflection and eliminate the need for polarization films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a first electrode with high reflectivity is used in a top emission type OLED, then the light extraction efficiency is improved, but color shift occurs due to light reflection
Solution Approach 1:
The patent introduces an intermediary layer (low refractive index layer or black matrix) between the high reflectivity electrode and the organic electro luminescent layer. This intermediary acts as a mediator that allows the electrode to maintain its high reflectivity for light extraction while preventing the harmful color shift caused by direct light reflection from the electrode surface.
2Object-affected harmful factors
If a polarization film is added to reduce glare in top emission OLED, then viewing comfort is improved, but optical efficiency decreases and manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the polarization film from the device structure entirely. Instead of adding a polarization film to reduce glare, the invention uses the black matrix and low refractive index layer to achieve glare reduction through controlled light reflection and absorption, thereby removing the source of optical efficiency loss and additional manufacturing costs.
3Manufacturing precision
If a black matrix is added below the first electrode to reduce light reflection, then color accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the black matrix function with the existing electrode support structure and encapsulation layers. The low refractive index layer is integrated into the existing device architecture, combining multiple functions (light reflection control, structural support, and encapsulation) into unified layers, thereby reducing overall device complexity while maintaining color accuracy.
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 solution effectively reduces color shift and manufacturing costs by minimizing light reflection and eliminating the need for polarization films, enhancing the optical efficiency of the device.
Implementation Method 1
an organic electro luminescent layer 140 and a second electrode 160 which are formed on the first electrode 120
Implementation Method 2
the reflection of light from the first electrode is minimized by forming the black matrix below the first electrode or forming the first electrode of metal with low reflectivity
Data Source
AI summary
An organic electro luminescence device is provided. First and second substrates are arranged to face each other. A thin film transistor (TFT) is formed on the first substrate in each sub-pixel. A first electrode is formed on the first substrate and connected to the TFT. An organic electro luminescent layer and a second electrode are formed on the first electrode. A black matrix is disposed below the first electrode.