Patterned Optical Member for Display Light Extraction and Reflectance Reduction
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Solution Overview
Problem
Organic light emitting display apparatuses face reduced light extraction efficiency due to total reflection at interfaces, leading to increased reflectance from external light, which limits power savings and causes radial rainbow and circular ring patterns, as well as degraded black visibility.
Innovation Solution
An optical member with a first layer having concave and convex portions and a second layer with different refractive indices, converting external light into diffractive light to reduce intensity and suppress diffraction patterns, is integrated into the display apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light extraction efficiency is increased by reducing total reflection at interfaces, then light extraction efficiency is improved, but reflectance from external light increases
Solution Approach 1:
The patent applies local quality by creating a patterned structure with multiple regions having different refractive indices (convex portions with higher refractive index, concave portions with lower refractive index) within the optical member. This localized variation in refractive index allows different regions to perform different functions: convex portions reduce external light reflectance while concave portions maintain light extraction efficiency, thereby resolving the contradiction between these two opposing requirements.
2Object-affected harmful factors
If external light reflectance is reduced to improve display quality, then radial rainbow and circular ring patterns are suppressed, but light extraction efficiency may be compromised
Solution Approach 1:
The patent utilizes parameter changes by carefully controlling the refractive index values of different portions of the optical member. The convex portions are designed with a first refractive index while concave portions have a second refractive index, creating a specific refractive index gradient that simultaneously suppresses external light diffraction patterns and maintains effective light extraction. This parameter optimization resolves the contradiction between display quality and light extraction efficiency.
3Object-affected harmful factors
If an optical member with patterned structure is introduced to reduce external light reflectance, then diffraction patterns are minimized, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single optical member by integrating both light extraction and external light suppression capabilities into one component. The optical member combines a light extraction portion with a patterned structure (convex and concave portions) that simultaneously performs light extraction and suppresses external light diffraction patterns. This merging approach reduces overall device complexity compared to using separate components for each function.
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 enhances light extraction efficiency, minimizes radial patterns, and improves black visibility by reducing external light intensity and diffraction interference, thereby achieving better power management and display quality.
Implementation Method 1
the first layer and the second layer have their respective refractive indexes different from each other
Implementation Method 2
converting external light into diffractive light to reduce intensity and suppress diffraction patterns
Implementation Method 3
minimizing and reducing occurrence of a radial rainbow pattern and a radial circular ring pattern based on a diffraction pattern of reflective light generated by destructive interference and/or constructive interference of light caused by reflection of external light
Data Source
AI summary
An optical member capable of reducing reflectance of external light and a display apparatus comprising the same are provided. The optical member comprises a first layer including a pattern portion having a plurality of concave portions and a plurality of convex portions between the plurality of concave portions, and a second layer covering the pattern portion. The first layer and the second layer have their respective refractive indexes different from each other, and a first phase of light passing through the plurality of convex portions is different from a second phase of light passing through the plurality of concave portions.