Rollable Glass Sheet Structure for Vehicle Interior Impact Safety
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Solution Overview
Problem
Vehicle interior display systems require a rollable or foldable glass sheet that can transition between configurations while maintaining structural integrity and meeting headform impact testing requirements, without compromising aesthetics or increasing complexity.
Innovation Solution
A rollable or foldable glass sheet is ion-exchange strengthened to ensure depth of compressive stress within specific ranges at various bend radii, combined with a support structure and retraction mechanism that allows the glass sheet to reversibly transition between flat and bent configurations, meeting both storage and deployed state requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the glass sheet is made rigid to meet headform impact testing requirements, then safety and structural integrity are improved, but the ability to roll or fold without breaking deteriorates
Solution Approach 1:
The glass sheet has different mechanical properties in different regions: the central portion maintains high rigidity for impact resistance, while the peripheral regions near the edges are designed with different characteristics to allow bending and rolling. This local differentiation enables the glass to meet both safety requirements and rollability requirements simultaneously.
2Adaptability or versatility
If the glass sheet is made thin to enable easy rolling and folding, then rollability is improved, but structural integrity and safety deteriorate
Solution Approach 1:
The glass sheet employs asymmetric thickness distribution, being thinner at the edges to facilitate rolling and folding, while maintaining adequate thickness in the central region to ensure structural integrity and meet safety standards. This asymmetric design resolves the contradiction between rollability and strength.
3Strength
If the glass sheet is strengthened through ion exchange to increase compressive stress, then strength is improved, but the depth of compressive stress increases which may affect bending performance
Solution Approach 1:
The ion exchange process parameters are precisely controlled to achieve the optimal balance between strength enhancement and bending capability. By adjusting the ion exchange duration, temperature, and composition, the compressive stress depth is optimized to provide sufficient strength while maintaining the ability to bend to the required radius without fracture.
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 solution provides a structurally robust and aesthetically integrated display system that meets headform impact testing standards while allowing for seamless retraction and deployment, ensuring the glass sheet's safety and functionality in vehicle interiors.
Implementation Method 1
the glass sheet is ion-exchange strengthened so as to ensure that the depth of compressive stress (DOC) at a bend radius of 50 mm is greater than 11 μm
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
Embodiments of the disclosure relate to a rollable glass sheet configured to reversibly transition between a flat configuration and a bent configuration. The rollable glass sheet includes a first major surface and a second major surface opposite to the first major surface. The first major surface and the second major surface define a thickness of the glass sheet that is 0.4 mm or less. In the flat configuration, the first major surface includes a first surface compressive stress and a first depth of compression, and in the bent configuration, the first major surface includes a curvature. At a radius of curvature of 50 mm, the first major surface includes a second surface compressive stress less than the first compressive stress and a second depth of compression less than the first depth of compression and greater than 11 µm.