Curable Inkjet Films for OLED Encapsulation
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Solution Overview
Problem
Organic light-emitting diode (OLED) devices are susceptible to degradation from water and oxygen, requiring effective encapsulation methods to maintain stability and reliability, and existing deposition techniques often involve vacuum processes that are costly and inefficient.
Innovation Solution
The use of curable ink compositions deposited via inkjet printing, forming a polymeric film as part of a multilayered encapsulation stack with inorganic barrier layers, which provides protection and improves light extraction and thermal dissipation, while eliminating the need for vacuum processing and masking techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum deposition processes are used to deposit planarizing layers, then film quality and uniformity are improved, but processing cost and system complexity increase
Solution Approach 1:
The patent replaces vacuum-based physical vapor deposition with inkjet printing technology, substituting a complex mechanical vacuum system with a simpler liquid dispensing system. The inkjet process deposits organic precursor materials that are then cured in-situ to form the planarizing layer, eliminating the need for vacuum chambers while achieving comparable film quality through controlled liquid deposition and thermal or photonic curing.
Solution Approach 2:
The patent changes the deposition state from vapor phase (vacuum) to liquid phase (inkjet), and introduces a curing parameter (thermal or photonic treatment) to complete the film formation. This parameter transformation allows the same functional outcome (planarizing layer formation) to be achieved through a different physical state and additional curing step, simplifying the overall system.
2Loss of substance
If inkjet printing is used to deposit organic layers, then material waste and processing steps are reduced, but film quality and uniformity may deteriorate
Solution Approach 1:
The patent applies preliminary substrate preparation including surface treatment and heating before inkjet deposition to ensure optimal wetting and uniformity. The substrate is pre-heated to control solvent evaporation rates during deposition, and surface energy is modified to promote uniform ink spreading, thereby achieving consistent film quality despite the localized nature of inkjet printing.
Solution Approach 2:
The patent implements continuous scanning motion of the inkjet array across the substrate, ensuring continuous deposition without gaps or overlaps. The inkjet system maintains constant deposition rate and spacing through precision motion control, and the curing process immediately follows deposition to lock in the uniform structure, maintaining continuous useful action throughout the process.
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 effectively protects OLED devices from moisture and oxygen, enhances light extraction, and reduces material waste and processing complexity, resulting in stable and efficient encapsulation with improved mechanical and optical properties.
Implementation Method 1
inkjet deposition can be used for the deposition of an organic thin film composition on a substrate, followed by a curing process to form an organic layer on a substrate
Data Source
AI summary
The present teachings relate to various embodiments of a curable ink composition, which once printed and cured form polymeric films on a substrate such as, but not limited by, an OLED device substrate. Various embodiments of the curable ink compositions comprise di(meth)acrylate monomers, as well as multifunctional crosslinking agents and curing kinetics control additives.