Plastic Substrate Hardness via Hybrid Coating Layers
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Solution Overview
Problem
Current plastic substrates lack the necessary hardness and abrasion resistance to replace glass in mobile devices, which are desired for their lightweight and durability characteristics.
Innovation Solution
A plastic substrate is developed with a transparent plastic support member coated with a first inorganic layer of silicon oxide and a silicone polymer, and a first organic-inorganic hybrid layer containing polymer resin and inorganic particles, along with additional layers for enhanced bonding and stress buffering, achieving a structure with hardness and abrasion resistance comparable to glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass is used as a front-surface window, then hardness and abrasion-resistance are improved, but weight increases
Solution Approach 1:
The patent applies composite materials by combining plastic substrate with multiple coating layers including inorganic layers (silicon oxide, silicon nitride) and organic-inorganic hybrid layers. This composite structure achieves glass-equivalent hardness and abrasion-resistance while maintaining the inherent light weight of plastic materials, directly resolving the contradiction between strength and weight
2Strength
If glass is used as a front-surface window, then hardness and abrasion-resistance are improved, but damage from external impacts increases
Solution Approach 1:
The patent changes the material parameter from glass to plastic substrate while compensating for hardness through multi-layer coating applications. The plastic material inherently provides better impact resistance and flexibility compared to glass, while the coating layers maintain surface hardness, thus resolving the contradiction between hardness and impact damage resistance
3Strength
If a hard-coating layer is introduced to a plastic base, then hardness is improved, but difficulty in achieving glass-equivalent abrasion-resistance increases
Solution Approach 1:
The patent uses composite materials with specific inorganic layers (silicon oxide, silicon nitride) and organic-inorganic hybrid layers containing silane coupling agents. This composite coating system achieves glass-equivalent abrasion-resistance on plastic substrates through controlled deposition processes, resolving the manufacturing difficulty while achieving the desired hardness
Solution Approach 2:
The patent applies different coating layers with specific compositions and thicknesses at different locations and depths. The inorganic layers provide hardness while the organic-inorganic hybrid layers provide adhesion and flexibility, creating a locally optimized structure that achieves glass-equivalent abrasion-resistance without compromising the overall ease of manufacture
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 resulting plastic substrate exhibits mechanical properties such as pencil hardness, scratch resistance, and impact resistance equivalent to glass, while maintaining lightness and optical clarity, making it suitable for use in mobile devices.
Implementation Method 1
the silicone polymer may include at least one selected from a repeating unit represented by the following Chemical Formula 1 and a repeating unit represented by the following Chemical Formula 2... at least one selected from R1, R2, R3, and R4 may be one selected from an acrylic polymerizing group and a vinyl polymerizing group
Implementation Method 2
the first organic-inorganic hybrid layer may include a polymer resin and inorganic particles dispersed in the polymer resin
Implementation Method 3
a first inorganic layer on a surface of the plastic support member... and a first organic-inorganic hybrid layer on the first inorganic layer
Data Source
AI summary
A plastic substrate includes: a transparent plastic support member; a first inorganic layer on a surface of the plastic support member; and a first organic-inorganic hybrid layer on the first inorganic layer. A display device includes a display panel and a window on the display panel, the window including the plastic substrate.