Optical Adhesive Layer for OLED Photon Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional OLEDs face challenges such as refractive index mismatch between organic layers and glass substrates, leading to photon loss, and are sensitive to harsh environmental conditions, requiring protection and materials with specific refractive index and thermal stability.
Innovation Solution
A two-component filler composition with monomers of specific formulas, including a procatalyst and an activator, that mass polymerize to form a transparent optical layer with a refractive index of 1.4 to 1.7, compatible with OLED stacks, offering high transparency, thermal stability, and adhesion to both OLED and glass substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional OLED structures are used with glass substrate, then device simplicity is maintained, but refractive index mismatch causes photon loss and reduced light extraction efficiency
Solution Approach 1:
The patent introduces an optical adhesive layer as an intermediary between the OLED stack and glass substrate. This layer has a refractive index (1.4-1.7) that bridges the gap between the organic layers (n=1.7-1.9) and the glass substrate (n=1.5), enabling gradual refractive index transition and reducing photon loss through total internal reflection.
Solution Approach 2:
The patent changes the refractive index parameter of the adhesive layer to fall within 1.4-1.7, which is specifically optimized to match both the OLED organic layers and glass substrate. This parameter adjustment resolves the refractive index mismatch problem without requiring complex device structural modifications.
2Reliability
If OLEDs are exposed to environmental conditions, then device functionality is maintained, but sensitivity to moisture, oxygen, and temperature causes degradation
Solution Approach 1:
The patent employs an optical adhesive layer as a protective thin film that encapsulates the OLED stack. This film provides a barrier against moisture and oxygen penetration while allowing light transmission, thus protecting the sensitive organic materials from environmental degradation.
Solution Approach 2:
The optical adhesive layer creates a protected environment around the OLED stack, effectively isolating the organic layers from harmful atmospheric components such as moisture and oxygen, similar to creating an inert atmosphere that prevents chemical degradation.
3Loss of energy
If high refractive index materials are used to match organic layers, then light extraction is improved, but thermal stability and processing compatibility deteriorate
Solution Approach 1:
The patent optimizes the refractive index parameter of the adhesive layer to fall within 1.4-1.7, which balances light extraction efficiency with thermal stability. This refractive index range provides sufficient optical matching while using materials that can withstand OLED processing temperatures and operate reliably under device operating conditions.
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 into the substrate, provides protection against environmental conditions, and ensures uniform coating with low viscosity and rapid flow, maintaining optical transparency and thermal stability.
Implementation Method 1
norbornene (NB) based olefinic monomers, which undergo mass polymerization to form optical layers
Data Source
AI summary
Embodiments in accordance with the present invention encompass compositions encompassing components A and B which respectively contain a procatalyst and an activator along with one or more monomers which undergo vinyl addition polymerization when both components are mixed together to form a substantially transparent film. The monomers employed therein have a range of refractive index from 1.4 to 1.8 and thus these compositions can be tailored to form transparent films of varied refractive indices. Accordingly, compositions of this invention are useful in various opto-electronic applications, including as coatings, encapsulants, fillers, leveling agents, among others.