Stretchable Display Connection Line Adhesion
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Solution Overview
Problem
Stretchable display devices face reliability issues due to peeling and delamination of connection lines between adjacent circuits during stretching, leading to potential breakage and damage to thin film transistors, capacitors, and connection lines.
Innovation Solution
The solution involves reducing the steepness of the slope in the insulating layer in contact with connection lines, filling undercut portions in the substrate with an overcoating layer, and ensuring contact points of connection lines are disposed on protruding portions of a substrate to enhance stability and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If connection lines are formed on a flexible substrate that can be stretched, then the display device achieves flexibility and deformability, but peeling and delamination of connection lines occur during stretching
Solution Approach 1:
The substrate is divided into a flexible lower substrate and multiple rigid individual substrates. The connection lines are formed on the rigid individual substrates rather than directly on the flexible lower substrate, segmenting the structure to prevent peeling while maintaining overall flexibility.
Solution Approach 2:
Rigid individual substrates serve as intermediary elements between the flexible lower substrate and the connection lines. These intermediaries protect the connection lines from direct stress during stretching, preventing peeling and delamination while allowing the display device to maintain flexibility.
2Ease of manufacture
If the insulating layer has a steep slope in step, then manufacturing is simplified, but connection lines peel from the insulating layer during repeated stretching
Solution Approach 1:
The slope angle of the insulating layer step is changed from steep to gentle. This parameter modification improves adhesion strength and prevents peeling of connection lines during repeated stretching, while still allowing for practical manufacturing processes.
3Ease of manufacture
If connection lines transition over an undercut portion, then substrate manufacturing is achieved, but connection lines are prone to breakage
Solution Approach 1:
The undercut portion is filled with an overcoating layer before the connection lines are formed. This preliminary action creates a smooth, gradual slope that supports the connection lines, preventing breakage while still allowing for standard substrate manufacturing processes.
Solution Approach 2:
The overcoating layer serves as an intermediary material that fills the undercut portion and provides a smooth transition surface for the connection lines. This intermediary structure eliminates the sharp edges that would cause stress concentration and breakage.
Data Source
AI summary
In the stretchable display device of the present disclosure, peeling and delamination of connection lines between adjacent circuits mounted on individual fixed substrates that might occur during stretching is reduced. According to one embodiment a temporary substrate is formed having a plurality of stiff areas and an elastic area, the temporary substrate being on a subsidiary substrate. A plurality of individual substrates are disposed on the lower substrate and located in the active area on the lower substrate. A first inorganic layer is formed on each of the plurality of individual substrates, the first inorganic layer having a sidewall surface extending upward from the first substrate. An organic layer is deposited overlying the first inorganic layer, including overlying the sidewall surface of the first inorganic layer.