Folded OLED Display Protective Cover with Selective Hardening
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Solution Overview
Problem
OLED displays in information handling systems face structural support challenges that add thickness and susceptibility to damage due to torsional stresses, particularly when folded in convertible housings, as traditional hardened glass covers crack under such stress.
Innovation Solution
A protective cover is created by masking a portion of a glass sheet to remain workable, allowing it to fold over the substrate edge, with the hardened glass providing rigidity on the front and rear faces and a flexible, unhardened glass at the folded portion, coupled with a clear bezel for image presentation, and optionally using a carbon fiber or magnesium lithium alloy insert for additional support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hardened glass cover is used to protect the OLED display, then the display gains protection against scratches and damage, but the glass becomes susceptible to cracking under torsional stress when folded
Solution Approach 1:
The glass cover is selectively hardened only in specific regions (front and rear display surfaces) while leaving the folded edge regions unhardened. This is achieved through a masking process during the hardening treatment that prevents glass coating deposition or thermal hardening at the folded portions, allowing the glass to remain flexible where bending occurs while maintaining hardness and scratch resistance on the display surfaces.
Solution Approach 2:
The glass cover is functionally segmented into hardened regions (for protection) and unhardened regions (for flexibility). The masking technique divides the glass surface into zones with different properties, creating a heterogeneous structure where each zone serves its specific function - hardened zones provide scratch resistance while unhardened zones provide torsional flexibility.
2Reliability
If structural support is added to manage torsional stresses, then the display gains reliability, but the display thickness increases
Solution Approach 1:
The physical and chemical parameters of the glass cover are changed through selective hardening treatment. The hardened regions have increased surface hardness and compressive stress, while the unhardened regions maintain original flexibility. This parameter differentiation allows the same glass component to provide both structural support and torsional flexibility without adding thickness.
Solution Approach 2:
The glass cover becomes a composite structure with regions of different mechanical properties - hardened glass regions providing rigidity and unhardened regions providing flexibility. This composite approach allows a single material (glass) to exhibit multiple mechanical characteristics necessary for both protection and foldability.
3Ease of operation
If the protective cover is made fully flexible to allow folding, then the display can be folded, but the cover loses the ability to provide sufficient surface rigidity and protection
Solution Approach 1:
The protective cover exhibits local quality differentiation where the folded edge regions are kept flexible for ease of operation while the front and rear display surface regions are hardened for surface rigidity and protection. This spatial variation in material properties resolves the contradiction between foldability and protective capability.
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
This solution allows OLED displays to fold and present images on both sides of a housing portion with improved resistance to torsion forces, reduced manufacturing complexity, and a lightweight, rigid structure, while maintaining a thin form factor.
Implementation Method 1
heating and bending the untreated portion that was masked
Data Source
AI summary
A portable information handling system display has an OLED film disposed over front and rear faces of a substrate, such as a carbon fiber material. A protective cover is disposed over the OLED film with a folded portion along an end of the substrate, the protective cover hardened at the front and rear faces and left unhardened along the folded portion. In one example embodiment, a transparent bezel is placed over the folded portion with the OLED film presenting system information through the bezel, such as battery state, etc.