Laminate Shock Absorbing Layer Suppresses Shape Transfer
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Solution Overview
Problem
Existing hard coat films for image display devices are prone to shape transfer from external objects due to impact and rubbing, leading to scratches and cratering, particularly during transportation of devices like notebooks and smartphones.
Innovation Solution
A laminate comprising a shock absorbing layer with a maximum tan δ value in a specific frequency range (104 to 1013 Hz) at 25°C, a support, and a hard coat layer, where the shock absorbing layer has a storage modulus of 30 MPa or more and a thickness of 10 to 200 μm, incorporating a block copolymer of methyl methacrylate and n-butyl acrylate, and optionally an inorganic oxide layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hard coat layer is applied on a support to prevent scratches, then scratch resistance is improved, but shape transfer from external objects occurs due to impact and rubbing
Solution Approach 1:
The patent divides the protective film into multiple functional layers: a hard coat layer (for scratch resistance) and a shock absorbing layer (for impact cushioning). This segmentation allows each layer to perform its specialized function without interfering with the other, preventing shape transfer while maintaining scratch resistance.
Solution Approach 2:
The shock absorbing layer acts as an intermediary between the hard coat layer and external objects. It absorbs impact energy and reduces stress transmission to the hard coat layer, preventing shape transfer and damage while allowing the hard coat layer to maintain its scratch-resistant properties.
2Strength
If the hard coat layer is made harder to prevent scratches, then scratch resistance is improved, but impact resistance deteriorates due to increased brittleness
Solution Approach 1:
The patent separates the functions of scratch resistance and impact resistance into different layers. The hard coat layer provides scratch resistance through its hardness, while the shock absorbing layer provides impact resistance through its elasticity and energy absorption capabilities, eliminating the brittleness problem of hard materials.
Solution Approach 2:
The patent creates a composite structure combining a hard coat layer (made from curable composition with high hardness) and a shock absorbing layer (made from elastomer or viscous material). This composite material system combines the advantages of hard materials (scratch resistance) with soft materials (impact resistance), achieving both properties simultaneously.
3Reliability
If a shock absorbing layer is added to prevent shape transfer, then impact resistance is improved, but device complexity increases
Solution Approach 1:
The patent combines the shock absorbing layer and hard coat layer into a single integrated protective film that can be applied as one unit to the display surface. This merging approach simplifies the overall device structure compared to adding separate protective components, while still providing both impact and scratch protection.
Solution Approach 2:
The protective film with the shock absorbing layer serves multiple functions: it provides impact cushioning, prevents shape transfer, maintains scratch resistance, and preserves display visibility. This multi-functionality reduces the need for additional separate protective components, thereby reducing device complexity.
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 laminate effectively suppresses shape transfer from external objects, enhancing impact resistance and preventing scratches on the display surface while maintaining visibility and hardness.
Implementation Method 1
the shock absorbing layer has a maximum value of tan δ in a frequency range of 104 to 1013 Hz at 25° C., where the tan δ is a ratio of a loss modulus with respect to a storage modulus
Data Source
AI summary
A laminate includes a shock absorbing layer, a support, and a hard coat layer, in which the shock absorbing layer has a maximum value of tan δ in a frequency range of 104 to 1013 Hz at 25° C. The tan δ is a ratio of a loss modulus with respect to a storage modulus.