Patterned Glass Substrate Shape for Flexible Display Bending Strength
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Solution Overview
Problem
Glass substrates in flexible display devices face challenges in maintaining impact resistance and durability while allowing for deformation, as they are prone to breakage and require precise control of thickness and shape to enhance flexural strength.
Innovation Solution
A patterning method involving laser irradiation followed by alkali-based and acid-based etching is used to define patterns on the substrate, with controlled thickness and shape to increase flexibility and bending strength, including a first etching process for anisotropic etching and a second etching process for isotropic etching, adjusting etching times to achieve a rounded end portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a glass substrate with predetermined thickness is used to prevent breakage and increase impact resistance, then durability and impact resistance are improved, but flexibility and deformability deteriorate
Solution Approach 1:
The glass substrate is divided into patterned regions with different thicknesses, creating thin regions that enhance flexibility and thick regions that maintain strength and impact resistance. This segmentation allows the substrate to bend and deform while preserving overall structural integrity.
Solution Approach 2:
Different regions of the substrate are given different local properties through selective thinning. The thin regions provide flexibility for deformation, while the thick regions maintain high strength and impact resistance, allowing the substrate to have both flexible and strong characteristics in different locations.
2Reliability
If the substrate thickness is increased to prevent breakage in deformable portions, then reliability is improved, but the substrate becomes more prone to cracking during deformation
Solution Approach 1:
The substrate is segmented into thin and thick regions, where the thin regions accommodate deformation without cracking and the thick regions provide overall structural support and breakage resistance.
Solution Approach 2:
Rounded corners and curved transitions in the patterned regions reduce stress concentration points, preventing crack initiation and propagation during deformation while maintaining reliability.
3Productivity
If a single etching process is used to define patterns, then the patterning process is simpler and faster, but the precision and control of pattern shape deteriorate
Solution Approach 1:
The patterning process is segmented into multiple etching steps with different etchants, where each step contributes to achieving the final precise pattern shape. This multi-step approach provides better control over pattern geometry while maintaining reasonable production efficiency.
Solution Approach 2:
Different etching parameters (etchant type, concentration, temperature, time) are used in sequential steps to progressively achieve the desired pattern shape with high precision, allowing fine-tuned control over the etching depth and profile.
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 method enhances the bending strength of the substrate by precisely defining the pattern shape, simplifies the patterning process, and reduces time, while maintaining the substrate's integrity and flexibility.
Implementation Method 1
forming a reformed region on a substrate by irradiating a laser on a first surface of the substrate
Implementation Method 2
defining a first pattern corresponding to the reformed region by first etching the substrate, where the first etching is performed by an alkali-based etchant
Implementation Method 3
defining a second pattern that is further etched from the first pattern by second etching the substrate, where the second etching is performed by an acid-based etchant
Data Source
AI summary
A display device includes a substrate including a first surface from which a pattern including an end portion is defined and a second surface which is parallel to the first surface. When an inner radius from a reference line positioned above the end portion and parallel with the first surface of the substrate to a surface of the pattern defining about 90 degrees is referred to as a first inner radius and an inner radius from the reference line to the surface of the pattern defining about 45 degrees is a second inner radius, a ratio of the second inner radius to the first inner radius is about 0.7 or more.