Adhesive Layer with Differential Creep for Display Reliability
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Solution Overview
Problem
Existing display devices face challenges in improving the reliability of adhesive layers coupling display modules and windows, which affects the durability of the devices, especially in minimizing or bending non-display areas.
Innovation Solution
A display device with an adhesive layer comprising different mechanical properties, including a first adhesive portion overlapping with the non-display area and a second adhesive portion adjacent to it, both having distinct creep values and modulus values, is used to enhance the adhesive strength and reliability. The adhesive layer is formed by creating a preliminary adhesive layer with varying ultraviolet light exposure to achieve specific mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single adhesive layer is used to couple the display module and window, then the manufacturing process is simple, but the adhesive reliability and durability are insufficient
Solution Approach 1:
The adhesive layer is divided into multiple adhesive portions (first adhesive portion overlapping the non-display area, second adhesive portion adjacent to it) with different mechanical properties. Each portion has distinct creep values and modulus values, allowing them to perform different functions: the first portion provides strong bonding while the second portion accommodates stress and prevents delamination, thereby improving overall adhesive reliability without requiring a completely separate multi-layer structure
Solution Approach 2:
Different portions of the adhesive layer are赋予 different local mechanical properties through controlled UV irradiation. The first adhesive portion receives sufficient UV exposure to achieve low creep value and high modulus for strong bonding, while the second adhesive portion receives reduced UV exposure to maintain higher creep value and lower modulus for stress accommodation. This local differentiation of material properties improves adhesive reliability while maintaining a relatively simple single-layer structure
2Manufacturing precision
If uniform UV irradiation is applied to the adhesive layer, then the manufacturing process is simple, but the adhesive strength and mechanical properties are insufficient in different areas
Solution Approach 1:
A mask is placed over the adhesive layer before UV irradiation to pre-determine the irradiation pattern. The mask has transparent regions corresponding to the non-display area and opaque regions corresponding to the display area, automatically creating the desired differential curing without complex real-time control during irradiation
Solution Approach 2:
A mask is introduced as an intermediary tool between the UV light source and the adhesive layer. The mask selectively blocks or transmits UV radiation to different portions of the adhesive layer, enabling precise control of the curing process. The mask simplifies the manufacturing process by converting a complex differential irradiation task into a simple mask-placement operation
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 increases the adhesive strength between the display module and the window, improving the reliability and durability of the display device by blocking voids and planarizing step differences, thereby enhancing the mechanical properties of the adhesive layer.
Implementation Method 1
The adhesive layer is formed by creating a preliminary adhesive layer with varying ultraviolet light exposure to achieve specific mechanical properties
Data Source
AI summary
A display device includes a display panel including a display area and a non-display area, a window disposed on the display panel and including a base substrate and a printed layer disposed on a surface of the base substrate and overlapping with the non-display area, and an adhesive layer disposed between the display panel and the window. The adhesive layer includes a first adhesive portion overlapping with the non-display area, and a second adhesive portion adjacent to the first adhesive portion and having a creep value different from a creep value of the first adhesive portion.