OLED Encapsulation Viscosity Layer Water Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic light emitting display devices face issues with water permeation and separation due to the absorption of water by the encapsulation materials, leading to damage and defects in the device.
Innovation Solution
A viscosity layer with a filler capable of water absorption and having a cross-linkage functional group is interposed between the substrates, providing a viscosity characteristic at room temperature to prevent water permeation and maintain adhesion even with increased volume due to water absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water absorbent filler is used to prevent water permeation, then water absorption capability is improved, but volume expansion causes stress and adhesion deterioration
Solution Approach 1:
The patent changes the physical-chemical parameters of the encapsulation material by selecting a polymer with a glass transition temperature of -70°C to 10°C. This parameter selection ensures the material remains in a rubbery state at room temperature, providing both water absorption capability and flexibility to accommodate volume expansion without losing adhesion. The specific glass transition temperature range is the critical parameter that resolves the contradiction between water absorption and adhesion maintenance.
Solution Approach 2:
The patent uses a composite material system consisting of a polymer matrix (such as polyethylene, polypropylene, polyvinyl chloride, polyacrylonitrile, polyacrylic acid, carboxymethyl cellulose, or starch) combined with a water absorbent filler. This composite structure allows the polymer matrix to provide adhesion and flexibility while the filler provides water absorption capability. The synergistic combination of these materials resolves the contradiction by distributing functions across different components.
2Strength
If the encapsulation material is rigid to provide structural support, then mechanical strength is improved, but it cannot accommodate volume expansion from water absorption
Solution Approach 1:
The patent changes the mechanical properties of the encapsulation material by controlling the glass transition temperature to be between -70°C and 10°C. This ensures the material has rubbery elasticity at operating temperatures, allowing it to deform and accommodate volume expansion from water absorption while maintaining sufficient mechanical strength. The elasticity modulus and tensile strength parameters are also optimized to balance rigidity and flexibility.
Solution Approach 2:
The patent employs a dynamic encapsulation material that can change its physical state in response to environmental conditions. The material transitions between more rigid and more flexible states based on temperature and water content, allowing it to provide structural support when needed while accommodating volume changes during water absorption. This dynamic behavior resolves the contradiction between maintaining mechanical strength and allowing volume expansion.
3Reliability
If the sealing member is used to bond substrates, then water sealing is improved, but the empty space causes substrate damage under external force
Solution Approach 1:
The patent merges the functions of water absorption and mechanical cushioning into a single encapsulation material layer. The polymer-based encapsulation material simultaneously provides water sealing capability and mechanical support to protect substrates from external forces. This functional merging eliminates the need for separate components and resolves the contradiction by providing both water sealing and mechanical protection through one integrated material system.
Solution Approach 2:
The patent uses a composite encapsulation material that combines the water-repelling properties of hydrophobic polymers with the cushioning properties of elastic materials. This composite structure provides both water sealing capability and mechanical protection against external forces, resolving the contradiction between water sealing and substrate protection by distributing these functions within the same material system.
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
This solution effectively prevents water from entering the device and reduces the likelihood of separation between the substrates, thereby protecting the organic light emitting diode and passivation layers from damage.
Implementation Method 1
a viscosity layer interposed between the first substrate and the second substrate to cover entire areas of the first substrate and the second substrate, the viscosity layer including a filler capable of water absorption
Data Source
AI summary
Disclosed is an organic light emitting display device in which water is prevented from externally permeating thereinto. The organic light emitting display device comprises a first substrate on which an organic light emitting diode and a driving device designed to drive the organic light emitting diode are formed; a second substrate facing the first substrate; a viscosity layer interposed between the first substrate and the second substrate to cover entire areas of the first substrate and the second substrate, the viscosity layer including a filler capable of water absorption; and a first adhesion layer arranged to adhere the viscosity layer to the first substrate, wherein the viscosity layer is a material including a cross-linkage functional group and having a viscosity characteristic at room temperature.