Low-Expansion Metamaterial Laminate for Crack-Resistant THz Patterns
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Solution Overview
Problem
Metamaterials used for electromagnetic waves in the terahertz band face issues with reduced rigidity and increased risk of cracks due to thickness reduction, leading to internal stress from temperature and humidity changes.
Innovation Solution
A metamaterial with a base material having a thermal expansion coefficient of 80 ppm/K or less, a dielectric loss tangent of 0.01 or less, and a pattern thickness less than 5 μm, combined with a laminate structure including an organic film with low moisture permeability, to reduce internal stress and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thickness of the pattern is reduced to lower cost, then manufacturing cost is reduced, but rigidity of the pattern is lowered and internal stress is generated
Solution Approach 1:
The patent changes the material parameter (thermal expansion coefficient) of the base material to 80 ppm/K or less, which fundamentally alters the stress characteristics of the system. This parameter change allows the thin pattern to maintain sufficient rigidity and resist cracking despite reduced thickness, thus resolving the contradiction between cost reduction and strength maintenance.
Solution Approach 2:
The patent creates a composite structure consisting of the pattern layer and the base material layer with specific thermal expansion properties. By carefully selecting the base material to have a thermal expansion coefficient of 80 ppm/K or less, the composite structure achieves optimal stress distribution, allowing thin patterns to maintain rigidity without cracking while keeping manufacturing costs low.
2Ease of manufacture
If the thickness of the pattern is reduced, then manufacturing cost is reduced, but internal stress from temperature and humidity changes is generated
Solution Approach 1:
The patent changes the thermal expansion parameter of the base material to 80 ppm/K or less, which fundamentally alters how the system responds to temperature and humidity changes. This parameter optimization minimizes differential expansion between the pattern and base material, thereby reducing internal stress and preventing cracks in thin-pattern configurations.
Solution Approach 2:
The patent converts the potentially harmful effect of thermal expansion mismatch into a beneficial outcome by selecting a base material with specifically low thermal expansion coefficient (80 ppm/K or less). This transforms the temperature and humidity changes from stress-generating factors into manageable environmental conditions, allowing thin patterns to maintain reliability while reducing manufacturing cost.
3Ease of manufacture
If the thickness of the pattern is reduced, then manufacturing cost is reduced, but cracks occur in the pattern
Solution Approach 1:
The patent optimizes the thermal expansion coefficient parameter of the base material to 80 ppm/K or less, which fundamentally changes the stress state of the thin pattern. This parameter optimization prevents crack formation by ensuring that thermal and humidity-induced stresses remain below the fracture threshold of the thin pattern, thus allowing cost-effective thin-pattern designs without crack-related failures.
Solution Approach 2:
The patent transforms the potentially crack-causing thermal and humidity variations into benign environmental factors by using base material with optimized low thermal expansion coefficient. This conversion allows thin patterns to withstand temperature and humidity changes without cracking, making thin-pattern metamaterials both cost-effective and reliable.
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 effectively suppresses the occurrence of cracks in the metamaterial, enhancing its stability and performance while maintaining electromagnetic wave functionality.
Implementation Method 1
a thermal expansion coefficient of the base material is 80 ppm/K or less
Implementation Method 2
a dielectric loss tangent of the base material is 0.01 or less
Implementation Method 3
an organic film provided on a surface of the metamaterial on a pattern side, wherein a moisture permeability of the organic film in an environment of a temperature of 40° C. and a relative humidity of 90% is 3,000 g/(m2 24 hours) or less
Data Source
AI summary
Provided are a metamaterial including a base material having a dielectric loss tangent of 0.01 or less and a pattern provided on a surface of the base material, in which the pattern is composed of at least one of a conductive material or a material which transits from an insulator to a conductor, and a thermal expansion coefficient of the base material is 80 ppm/K or less; and a laminate including the metamaterial.