Electroluminescent Display Micro Lens Structure for Dual-Direction Light Extraction
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Solution Overview
Problem
Electroluminescent display devices suffer from low light extraction efficiency due to optical waveguide modes generated by surface plasmon components, and there is a demand for devices that can emit light in both directions, particularly for dual-display applications.
Innovation Solution
The electroluminescent display device incorporates a micro lens structure with protruding and depressed portions on an overcoat layer, along with a reflective pattern and insulating or color filter patterns, to refract and reflect light effectively in both directions, improving light extraction efficiency and enabling dual emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional electroluminescent display device structure is used, then the device is simple to manufacture, but light extraction efficiency is low due to optical waveguide modes trapping 60-70% of emitted light
Solution Approach 1:
The overcoat layer is segmented into multiple protruding portions and depressed portions, creating a micro-lens array structure that divides the light extraction function into multiple localized regions, effectively reducing optical waveguide mode trapping
Solution Approach 2:
The invention introduces a vertical dimension to light extraction by creating protruding portions that extend upward from the overcoat layer, transforming the planar light extraction interface into a three-dimensional micro-lens structure that redirects trapped light
2Adaptability or versatility
If a conventional single-direction light emission structure is used, then the device structure is simple, but the device cannot meet dual-display application requirements
Solution Approach 1:
The micro-lens array structure serves multiple functions simultaneously: it extracts light in both upward and downward directions, maintains color accuracy through integrated color filter patterns, and simplifies manufacturing by combining multiple functions into a single structural configuration
Solution Approach 2:
The invention merges the color filter patterns directly with the overcoat layer structure, integrating what would traditionally be separate components into a unified structure that simultaneously handles light filtration and directional extraction
3Ease of manufacture
If color filter patterns are aligned with emissive areas in conventional devices, then color accuracy is maintained, but the manufacturing process is complex and time-consuming
Solution Approach 1:
The color filter patterns are pre-aligned with the protruding portions during the overcoat layer formation process, establishing precise alignment before subsequent manufacturing steps, which eliminates the need for complex post-alignment procedures
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 enhances light extraction efficiency and allows for effective emission of light in both directions, simplifying the manufacturing process and addressing the challenge of aligning color filter patterns with emissive areas.
Implementation Method 1
The electroluminescent display device incorporates a micro lens structure with protruding and depressed portions on an overcoat layer, along with a reflective pattern and insulating or color filter patterns, to refract and reflect light effectively in both directions
Implementation Method 2
The electroluminescent display device incorporates a micro lens structure with protruding and depressed portions on an overcoat layer, along with a reflective pattern and insulating or color filter patterns, to refract and reflect light effectively in both directions
Data Source
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AI summary
An electroluminescent display device includes a first substrate including an emissive area; an overcoat layer disposed over the first substrate and including a plurality of protruding portions and a plurality of depressed portions in the emissive area; a first electrode disposed over the overcoat layer and including an electrode portion which corresponds to each of the plurality of protruding portions and an opening which corresponds to each of the plurality of depressed portions; a light-emitting layer disposed over the electrode portion; a second electrode disposed over the light-emitting layer; and a reflective pattern disposed over each of the plurality of depressed portions.