Adhesive Layer Thermal Stability in Flexible Display Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flexible display devices face challenges in maintaining reliability and stability due to deformation, particularly in folding and unfolding processes, as existing adhesive layers lack sufficient thermal stability and durability.
Innovation Solution
A display device with an adhesive layer having a thermal decomposition starting temperature of 300°C or higher and a peak temperature of 350°C or higher, made from materials like epoxy-based, urethane-based, or siloxane-based resins, is used between the display panel and window, ensuring alignment of edges and optimal thickness for enhanced durability and manufacturing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional adhesive layer is used in flexible display devices, then the device can be manufactured with basic bonding functionality, but the adhesive layer lacks sufficient thermal stability and durability during folding and unfolding processes
Solution Approach 1:
The patent changes the thermal parameters of the adhesive layer by selecting materials with specific thermal decomposition characteristics (starting temperature ≥300°C, peak temperature ≥350°C). This parameter modification enables the adhesive layer to withstand thermal stresses during folding operations while maintaining bonding reliability, directly resolving the contradiction between thermal stability and manufacturing reliability.
Solution Approach 2:
The patent employs composite material selection by evaluating and combining adhesive materials with specific properties (epoxy-based, urethane-based, or siloxane-based resins) that simultaneously provide thermal stability and durability. This composite approach allows the adhesive layer to maintain both high thermal resistance and reliable bonding performance throughout the device lifecycle.
2Reliability
If the adhesive layer has high thermal decomposition temperature, then thermal stability is improved, but the adhesive layer may become too rigid for flexible deformation
Solution Approach 1:
The patent carefully adjusts multiple parameters of the adhesive layer including thermal decomposition temperature (≥300°C), peak temperature (≥350°C), storage modulus (10-50 KPa at 60°C), and thickness (25-75 μm). By coordinating these parameters, the adhesive layer achieves optimal balance between thermal stability and flexibility, allowing it to withstand both high temperatures and repeated bending without cracking or delaminating.
Solution Approach 2:
The patent selects from composite material options (epoxy-based, urethane-based, siloxane-based resins) that inherently combine thermal resistance with flexibility. These composite materials provide the necessary mechanical compliance for flexible deformation while maintaining high thermal decomposition temperatures, resolving the contradiction between rigidity and adaptability.
3Reliability
If the adhesive layer area is increased beyond the window area, then bonding coverage is improved, but the adhesive layer may experience excessive stress during folding
Solution Approach 1:
The patent applies local quality by positioning the adhesive layer to extend beyond the window area (area of adhesive layer > area of window) while controlling its edges to align with the display panel edges. This localized extension ensures comprehensive bonding coverage in critical areas while the overall geometry is designed to distribute stress uniformly during folding, preventing concentration of forces in specific regions.
Solution Approach 2:
The patent addresses the area-stress contradiction by considering the three-dimensional configuration of the adhesive layer, particularly its thickness (25-75 μm) and how it bridges the gap between the window and display panel. The dimensional parameters are optimized to provide sufficient bonding area while maintaining flexibility and stress distribution capabilities throughout the folding motion.
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 provides improved thermal stability and durability, allowing for repeated folding and unfolding while preventing damage to components, thus enhancing the reliability and manufacturing process of flexible display devices.
Implementation Method 1
the adhesive layer has a thermal decomposition starting temperature of about 300° C. or higher and a thermal decomposition peak temperature of about 350° C. or higher
Implementation Method 2
the thermal decomposition peak temperature is defined as a temperature at which an amount of weight loss or gas generation caused by thermal decomposition is maximized
Data Source
AI summary
A display device includes a display panel, a functional layer disposed on the display panel, where the functional layer includes at least one selected from an optical layer and an impact absorbing layer, a window disposed on the functional layer, and an adhesive layer disposed between the functional layer and the window. The adhesive layer has a thermal decomposition starting temperature of about 300° C. or higher and a thermal decomposition peak temperature of about 350° C. or higher, where the thermal decomposition peak temperature is defined as a temperature at which an amount of weight loss or gas generation caused by the thermal decomposition is maximized.