Foldable Glass Window With Local Ion Strengthening
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Solution Overview
Problem
Flexible electronic devices require a window that maintains excellent folding characteristics without compromising mechanical properties and impact resistance.
Innovation Solution
A window design with a folding portion and non-folding portions having different surface compressive stresses, achieved through selective chemical strengthening using varying concentrations of K+ and Na+ ions, and a recessed lower surface at the folding portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the entire window is chemically strengthened to improve impact resistance, then mechanical properties are improved, but folding characteristics deteriorate
Solution Approach 1:
The window is divided into different regions with different chemical strengthening degrees: the first region (non-folding area) has high surface compressive stress (≥300 MPa) for impact resistance, while the second region (folding area) has lower surface compressive stress (<300 MPa) to enable flexible folding. This local differentiation resolves the contradiction by applying strong strengthening where needed and weak strengthening where flexibility is required.
2Adaptability or versatility
If the window is made flexible to enable folding, then portability is improved, but mechanical strength deteriorates
Solution Approach 1:
Different regions of the window are assigned different strengthening levels: the folding region maintains lower compressive stress to preserve flexibility and folding capability, while non-folding regions receive higher strengthening to maintain overall mechanical strength. This allows the window to be both flexible and strong simultaneously.
3Strength
If chemical strengthening is applied uniformly across the window, then impact resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The chemical strengthening process is applied with spatial variation in strengthening degree, creating regions of different compressive stress levels. This is achieved through controlled ion exchange processes that deposit different concentrations of alkaline earth metal ions in different regions, allowing differentiated protection without requiring multiple separate manufacturing steps.
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 window exhibits enhanced folding characteristics and impact resistance, ensuring durability and functionality in flexible electronic devices.
Implementation Method 1
a first non-folding portion, and a second non-folding portion spaced from the first non-folding portion with the folding portion interposed therebetween. The non-folding portion has a surface compressive stress less than a surface compressive stress of the folding portion
Data Source
AI summary
A window for a window cover of an electronic device, includes: a glass material; a lower surface; an upper surface opposite to the lower surface; a folding portion to be folded relative to a folding axis extending in a first direction; and a non-folding portion including a first non-folding portion, and a second non-folding portion spaced from the first non-folding portion with the folding portion interposed therebetween. The non-folding portion has a surface compressive stress less than a surface compressive stress of the folding portion.