Semi-transparent Metal Layer Suppresses Reflection in OLED
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices with metallic reflective layers suffer from high external light reflectivity, leading to reduced contrast and color distortion when used near windows or outdoors, and the use of circular polarizers to mitigate this issue decreases light emission intensity and increases manufacturing costs.
Innovation Solution
A display device configuration that includes a thin film transistor layer, a light-emitting element layer with a first electrode comprising a transparent electrode, a reflective metal layer, and a semi-transparent metal layer, which absorbs light to suppress reflectivity, eliminating the need for a circular polarizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a circular polarizer is used to suppress external light reflection, then external light reflection is reduced, but light emission intensity is significantly reduced
Solution Approach 1:
The reflective metal layer is segmented into multiple layers with different reflective characteristics. The first reflective metal layer (Ag) provides high reflectivity, while the second reflective metal layer (Al) with lower reflectivity is added to suppress external light reflection. This segmentation allows the system to achieve both high light emission intensity and reduced external light reflection without using a circular polarizer.
2Object-affected harmful factors
If a circular polarizer is used to suppress external light reflection, then external light reflection is reduced, but manufacturing cost increases
Solution Approach 1:
The circular polarizer component is extracted and removed from the display device structure. Instead, the invention uses a multi-layer reflective metal layer configuration (Ag layer + Al layer) that inherently suppresses external light reflection through differential reflectivity, eliminating the need for expensive circular polarizer materials and simplifying the manufacturing process.
3Illumination intensity
If a highly reflective metal layer is used to improve light emission, then light emission intensity is improved, but external light reflection increases
Solution Approach 1:
Different regions of the reflective metal layer structure are assigned different reflective qualities. The first reflective metal layer (Ag) has high reflectivity for light emitted from the light-emitting layer, while the second reflective metal layer (Al) has lower reflectivity specifically for external light incident from the display surface side. This local quality differentiation allows simultaneous achievement of high light emission intensity and suppressed external light reflection.
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 effectively reduces external light reflection without using a circular polarizer, maintaining light emission intensity and reducing manufacturing costs while enhancing contrast and viewing angle characteristics.
Implementation Method 1
The first electrode includes a first transparent electrode, a reflective metal layer, and a semi-transparent metal layer in this order on the thin film transistor layer. By absorbing light in the semi-transparent metal layer, reflectivity can be suppressed
Implementation Method 2
A display device such as a top-emitting organic EL (electroluminescence) display device includes a metallic reflective layer made of, for example, highly reflective metal such as silver on the lower layer side of a light-emitting layer
Data Source
AI summary
A display device includes a light-emitting element layer including a plurality of light-emitting elements in each of which a first electrode, a function layer including a light-emitting layer, and a second electrode are disposed in this order from a thin film transistor layer side, and the first electrode includes a first transparent electrode, a reflective metal layer, and a semi-transparent metal layer in this order from the side opposite to the light-emitting layer.