OLED Encapsulating Film with Low Permittivity and High Hardness
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Solution Overview
Problem
Existing encapsulating materials for organic light-emitting diodes (OLEDs) face challenges in achieving a balance between low permittivity and high film hardness, which affects the sensitivity of touch sensors and the integrity of the display device when exposed to external moisture and oxygen.
Innovation Solution
An encapsulating composition comprising a specific combination of photocurable monomers represented by Formulas 1 and 2, along with hollow silica particles, is used to form an encapsulating film with low permittivity and high film hardness, suitable for inkjet processes, ensuring effective protection of OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If materials with relatively high permittivity are used in organic layers, then film hardness is improved, but touch sensor sensitivity deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the organic layer by using specific photocurable monomers (acrylates and vinyl monomers) with controlled molecular structures and ratios, achieving a permittivity of 3.2 F/m or less while maintaining film hardness of 1,000 MPa or more, thus resolving the contradiction between hardness and sensor sensitivity
Solution Approach 2:
The patent employs a composite material system combining multiple photocurable monomers (acrylate monomer, vinyl monomer, and crosslinking agent) in specific proportions, creating an encapsulating layer with optimized electrical and mechanical properties that simultaneously satisfies both hardness and low permittivity requirements
2Reliability
If inorganic layers are formed using plasma CVD or sputtering, then barrier performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces complex plasma CVD or sputtering processes with a simpler solution-based approach using photocurable organic encapsulating layers that can be applied by coating or printing methods, achieving comparable barrier performance against moisture and oxygen without requiring vacuum equipment or plasma generation systems
Solution Approach 2:
The patent changes the formation method parameter from physical vapor deposition (PVD) or chemical vapor deposition (CVD) to liquid-phase coating followed by photocuring, significantly simplifying the manufacturing process while maintaining effective encapsulation functionality
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 encapsulating film achieves permittivity of 3.2 F/m or less and modulus of 1,000 MPa or more, enhancing the sensitivity of touch sensors and preventing moisture and oxygen penetration, thereby improving the durability and performance of OLED devices.
Implementation Method 1
the encapsulating composition includes a photoinitiator; a first photocurable monomer represented by Formula 1 below; and a second photocurable monomer represented by Formula 2 below
Data Source
AI summary
Provided is an encapsulating composition for an organic light emitting diode, which includes a photoinitiator; a first photocurable monomer; and a second photocurable monomer, wherein the first and the second photocurable monomers do not include silicone or aromatic hydrocarbon, and an encapsulating composition having low permittivity and high film hardness suitable for an ink-jetting process is prepared, thereby providing a display device having a high sensitivity touch sensor.