Microstructured Glass Substrate for Flexible Display Durability
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Solution Overview
Problem
Existing flexible OLED displays face issues with fragility and brittleness due to thin glass layers, leading to high production costs and reject rates in the laser lift-off method, and are sensitive to oxygen and humidity, resulting in short lifespans.
Innovation Solution
A glass substrate with an essentially dimensionally stable portion and a flexible portion featuring recesses formed by concave microstructures, filled with polymer, which reduces thickness and enhances mechanical stability and flexibility, allowing for improved load-bearing capacity and protection against breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If glass layer thickness is reduced below 50 μm to achieve flexibility, then flexibility is improved, but mechanical strength deteriorates causing brittleness and breakage
Solution Approach 1:
The glass substrate is designed with spatially varying thickness: a first region with thickness of 5-50 μm for flexibility, and a second region with thickness of 50-200 μm for mechanical strength. This local differentiation allows the substrate to exhibit both flexible and mechanically robust properties in different areas, resolving the contradiction between flexibility and strength.
2Adaptability or versatility
If thin glass layers are used for flexibility, then adaptability is improved, but reliability deteriorates due to fragility
Solution Approach 1:
The substrate incorporates a thick second region (50-200 μm) that serves as a mechanically robust support structure, while the thin first region (5-50 μm) provides flexibility. The thick region acts as a reinforcement that prevents breakage during handling and laser lift-off processes, thereby improving reliability without sacrificing the flexibility needed for foldable displays.
3Weight of moving object
If laser lift-off method is used to remove back plane, then weight reduction is achieved, but manufacturing cost increases due to long process times and high reject rates
Solution Approach 1:
The glass substrate is pre-structured with a thickness gradient during manufacturing, with a thinner first region and a thicker second region. This preliminary structural preparation enables the subsequent laser lift-off process to proceed more efficiently and with fewer defects, as the pre-designed thickness distribution facilitates cleaner separation and reduces the risk of damage to the display components, thereby lowering reject rates and production costs.
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 substrate design passes the pen-drop test, ensuring mechanical stability and flexibility, while maintaining optical properties, and reduces production costs by minimizing damage during the laser lift-off process.
Implementation Method 1
at least one flexible portion (5), wherein at least in the flexible portion (5) a recess (6) is formed by a plurality of concave microstructures (12)
Implementation Method 2
The recess (6) is filled with a polymer (7)
Data Source
AI summary
A substrate made of glass includes an essentially dimensionally stable portion, one or more flexible portions, and one or more recesses on one side or which do not penetrate the substrate, and which is/are disposed in an outer surface of the substrate, so as to reduce a material thickness of the substrate in the flexible portion relative to an adjacent portion. The recess is formed in each case by a plurality of concave depressions that are defined by microstructures, a course of which determines a remaining material thickness of the substrate in the flexible portion. The depressions extend at least in portions into an area having a thickness parallel to the outer surface which on bending the substrate encloses a plane of a neutral axis between an extension zone and a compression zone of the substrate.