OLED Light Extraction Member Using Conic Lens Segmentation
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) suffer from low light extraction efficiency due to total internal reflection at the interface between the transparent substrate and the anode, which limits their optical extraction efficiency.
Innovation Solution
An OLED with a light extraction member featuring a plurality of unit lenses arranged on one surface, comprising a combination of two or more conic lenses in a honeycomb structure, where the first conic lens forms the lower part and the second conic lens forms the upper part, with specific curvature radii and conic constants to minimize total internal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a light extraction member with multiple conic lenses is used, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The light extraction member is divided into multiple unit lenses, each comprising a combination of first and second conic lenses with different curvature radii and conic constants. This segmentation allows each unit lens to independently optimize light extraction at different angles and positions, collectively achieving high extraction efficiency while maintaining manageable individual component complexity
Solution Approach 2:
The patent employs conic lenses with specifically designed curvature radii and conic constants to create curved optical surfaces. These curved surfaces effectively control light propagation paths, reducing total internal reflection by matching refractive index transitions and directing light extraction at optimal angles, thereby improving efficiency without requiring complex mechanical structures
2Productivity
If irregularities are formed on the transparent substrate, then light extraction efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
Instead of creating continuous irregularities on the substrate, the patent segments the light extraction function into discrete unit lenses with standardized conic geometries. This segmentation transforms the manufacturing challenge from creating complex continuous surface irregularities to fabricating repeatable modular lens units, reducing overall manufacturing precision requirements
Solution Approach 2:
The patent optimizes specific geometric parameters of the conic lenses, including curvature radii (r1, r2) and conic constants (k1, k2), to achieve effective light extraction. By carefully selecting these parameters, the design balances optical performance with manufacturability, ensuring that the lenses can be fabricated with standard precision while still achieving the desired light extraction enhancement
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
Significantly improves light extraction efficiency, enhancing energy efficiency and brightness of the OLED by reducing total internal reflection and light recycling within the device.
Implementation Method 1
Each of the unit lenses includes a first conic lens forming a lower part of the unit lens and a second conic lens forming an upper part of the unit lens
Implementation Method 2
The main reason that the light extraction efficiency is low is the occurrence of total internal reflection in which light is totally reflected into the OLED at the interface between the transparent substrate and the anode (transparent electrode) having a large refractive index
Data Source
Figure 1~3
AI summary
A light extraction member includes a plurality of unit lenses arranged on one surface thereof. Each of the unit lenses comprises a combination of two or more kinds of conic lenses.