Polymer-Ceramic Composite Housings for Portable Devices
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Solution Overview
Problem
Fiber-reinforced composites used in portable electronic device housings face challenges in achieving a balance between high stiffness, thinness, and cost-effectiveness, as traditional laminates may not provide sufficient resistance to deflection while maintaining a small thickness.
Innovation Solution
The use of a specific layup configuration in laminates, including unidirectional fibers aligned with the length and width, and off-axis fibers in outer sections, enhances resistance to shear deformations, allowing for thinner laminates with high resistance to deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional fiber-reinforced composites are used to increase stiffness, then resistance to deflection is improved, but thickness increases
Solution Approach 1:
The patent uses a hybrid composite material system combining ceramic particles (alumina, silica, titania) with polymer matrix (polyester, vinyl ester, epoxy) to achieve superior stiffness-to-thickness ratio. The ceramic reinforcement provides high modulus of elasticity while the polymer matrix provides toughness, enabling thin-walled structures with high resistance to deflection
Solution Approach 2:
The patent implements varying fiber orientations and ceramic particle distributions at different locations within the laminate structure. Surface layers have higher ceramic concentration for stiffness, while core layers have optimized fiber orientation for impact resistance, enabling thin overall thickness while maintaining high local stiffness where needed
2Weight of stationary object
If fiber-reinforced composites are used to reduce weight, then weight is reduced, but manufacturing cost increases
Solution Approach 1:
The patent optimizes fiber volume fraction (30-60%), ceramic particle concentration (10-40% by weight), and laminate thickness (0.5-2mm) to achieve the lightest possible weight while maintaining structural integrity. These parameter optimizations reduce material usage and enable simpler, more cost-effective manufacturing processes
Solution Approach 2:
The patent employs cost-effective thermoplastic and thermoset polymer matrices combined with readily available ceramic particles and standard fiber reinforcements. This approach uses economical materials that can be processed through conventional manufacturing methods, reducing overall cost while achieving lightweight performance
3Length of stationary object
If laminate thickness is reduced to make devices thinner, then device thickness is reduced, but resistance to shear deformations decreases
Solution Approach 1:
The patent divides the laminate into multiple thin layers with alternating fiber orientations (0°, 90°, ±45°). This segmented layered structure with total thickness 0.5-2mm provides cumulative resistance to shear deformations while maintaining overall thinness, as each layer contributes to shear stiffness through its orientation
Solution Approach 2:
The patent uses ceramic particle reinforcement (alumina, silica, titania) within the polymer-matrix composite to enhance shear modulus. The ceramic particles restrict polymer chain mobility and provide rigid reinforcement, maintaining shear resistance even as overall laminate thickness is reduced to 0.5-2mm
Data Source
AI summary
The present disclosure includes thin, high-stiffness laminates, portable electronic device housings including the same, and methods for making such laminates and portable electronic device housings. Some laminates include an inner section having one or more first laminae and one or more second laminae, and first and second outer sections disposed on opposing sides of the inner section, each having one or more third laminae The laminate has a width and a length that is perpendicular to the width. Each of the first lamina(e) can have fibers aligned in a direction parallel to the length, each of the second lamina(e) can have fibers aligned in a direction parallel to the width, and each of the third lamina(e) can have fibers aligned in a direction angnlarly disposed at an angle of at least 10 degrees to each of the length and the width.