Protective Film Hardness Gradient for Display Substrate Protection
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Solution Overview
Problem
Thin and fragile substrates in display devices are prone to scratches and cracks, and existing protective solutions like cover glass increase thickness and weight, while hardened films are susceptible to warping, deformation, and defects during cutting and application.
Innovation Solution
A protective film with a transparent substrate layer and a transparent hardened layer, where the hardened layer has a higher hardness in the middle portion and a lower hardness at the edges, formed by curing a photocurable coating with varying light irradiation durations to prevent burrs and deformation, facilitating easier cutting and attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hardened film is applied to protect the substrate, then protection against scratches and cracks is improved, but warping and deformation occur during cutting and application
Solution Approach 1:
The patent applies local quality by creating different hardness zones within the hardened layer: the edge region has lower hardness to prevent warping and enable easy cutting, while the middle region maintains high hardness for protection. This is achieved through selective light shielding during UV curing, where the edge regions receive less UV exposure than the middle region, resulting in the desired hardness gradient that resolves the contradiction between protection and stability.
2Reliability
If the hardened layer has high hardness for protection, then protection effectiveness is improved, but cutting becomes difficult and generates burrs
Solution Approach 1:
The patent resolves this contradiction by making the hardness property non-uniform across the hardened layer. The edge regions are designed with lower hardness through reduced UV irradiation, making them easy to cut without generating burrs, while the middle region maintains high hardness for effective protection. This localized property differentiation allows the material to exhibit both ease of cutting at edges and protection effectiveness in the center.
3Manufacturing precision
If uniform light irradiation is applied during curing, then curing completeness is improved, but edge regions become too hard and warp
Solution Approach 1:
The patent applies local quality by implementing non-uniform light irradiation during the curing process. A light-shielding plate is positioned to block UV light from reaching the edge regions while allowing full irradiation of the middle region. This results in the middle region achieving complete curing with high hardness for protection, while the edge regions remain partially uncured with lower hardness, preventing warping and maintaining stability.
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 film provides effective protection against scratches and cracks while maintaining a thin profile, reducing the risk of warping and deformation, and enabling precise cutting without generating air bubbles or dents, thus enhancing the durability and thinness of display devices.
Implementation Method 1
The transparent hardened layer is formed by curing a photocurable coating
Data Source
AI summary
A protective film includes a transparent substrate layer and a transparent hardened layer covering a surface of the transparent substrate layer. The transparent hardened layer includes a first region covering a middle portion of the transparent substrate layer and a second region covering an edge of the transparent substrate layer, where hardness of the first region is greater than hardness of the second region. The transparent hardened layer includes the first region and the second region.