OLED Microlens Light Extraction Efficiency
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices suffer from low light extraction efficiency, with only about 20% of emitted light being outputted, leading to increased power consumption and reduced device lifetime when attempting to enhance brightness.
Innovation Solution
The OLED display device incorporates a substrate with pixel regions, scattering portions, a first overcoat layer with concave portions, and a transparent electrode with air holes, forming microlenses on the surface of a second overcoat layer to guide and extract trapped light externally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If more current is applied to increase brightness, then brightness is improved, but power consumption increases and lifetime is reduced
Solution Approach 1:
The patent changes the optical parameters of the device by introducing microlenses with specific focal lengths and refractive indices. This modifies the light extraction parameter, enabling more efficient extraction of internally reflected light without changing the electrical input, thus improving brightness while maintaining or reducing power consumption
Solution Approach 2:
The microlenses act as intermediary optical elements between the organic light emitting layer and the external environment. These microlenses capture internally reflected light that would otherwise be trapped and redirect it outward, serving as a mediator to improve light extraction efficiency without requiring additional electrical energy
2Illumination intensity
If more current is applied to increase brightness, then brightness is improved, but device lifetime is reduced
Solution Approach 1:
By modifying the optical extraction parameter through microlens integration, the system achieves higher effective brightness output from the same electrical input, reducing the need to increase current and thereby preserving device lifetime
Solution Approach 2:
The microlenses serve as a passive optical intermediary that enhances light extraction without requiring additional electrical energy, thus avoiding the degradation mechanisms associated with higher current operation and extending device lifetime
3Ease of manufacture
If conventional flat structure is used, then device complexity is low, but light extraction efficiency is poor
Solution Approach 1:
The patent introduces curved microlens structures on the device surface, replacing the conventional flat geometry. These curved structures with specific focal lengths enable effective capture and redirection of internally reflected light, dramatically improving light extraction efficiency while maintaining manufacturing feasibility through established microlens fabrication techniques
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 improves light extraction efficiency by up to 60-70% of the total light produced, enhancing external luminous efficiency and reducing power consumption while maintaining device durability.
Implementation Method 1
a plurality of microlenses disposed on a surface of a second overcoat layer to guide the light emitted from the organic light emitting layer externally
Implementation Method 2
the light emitted from the organic light emitting layer is reflected internally while passing through a first electrode, a second overcoat layer, and a transparent electrode
Data Source
AI summary
An organic light emitting diode display device includes: a substrate including a plurality of pixel regions which each include an emission region and a non-emission region around the emission region; a plurality of scattering portions disposed on the substrate, corresponding to the emission region, and spaced apart from each other; a first overcoat layer disposed on the substrate having the plurality of scattering portions and including a plurality of concave portions which respectively correspond to the plurality of scattering portions; a first electrode disposed on the first overcoat layer in each of the plurality of pixel regions; and an organic light emitting layer and a second electrode sequentially disposed on the first electrode.