Overmolded Force Sensing Gasket for Liquid Ingress Protection
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Solution Overview
Problem
Portable electronic devices face challenges in maintaining a tight seal against contaminants and water ingress, especially when incorporating force sensors, as existing adhesives can degrade under harsh conditions, leading to potential failures in performance and functionality.
Innovation Solution
A force sensing gasket composed of a layered stack of flexible circuits encapsulated in a compliant silicone material, which is compression or injection molded to reduce sealing interfaces and enhance resistance to contaminants, featuring channels for liquid adhesives and aligning features for correct positioning, thereby creating a robust environmental seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing adhesives are used to seal the cover glass to the housing, then the device can be assembled easily, but the adhesive degrades under harsh conditions leading to seal failure
Solution Approach 1:
The patent changes the material parameters by replacing degradable adhesive materials with chemically inert gasket materials that maintain their sealing properties under harsh conditions including water exposure, chemical contact, and temperature variations, thereby resolving the contradiction between ease of assembly and long-term seal reliability
Solution Approach 2:
The patent employs composite gasket structures combining multiple materials with complementary properties - including chemically inert materials for chemical resistance, compliant materials for sealing pressure distribution, and integrated force-sensing components - to achieve both ease of assembly and high reliability in harsh environments
2Adaptability or versatility
If multiple sealing interfaces are used to seal around force sensors, then the force sensing function can be implemented, but the number of sealing interfaces increases leading to more contamination pathways
Solution Approach 1:
The patent merges the force-sensing function and sealing function into a single integrated gasket component, eliminating the need for separate sealing interfaces around force sensors. The gasket incorporates force-sensing elements directly within its structure, allowing it to maintain both sealing integrity and force detection capability while reducing the number of potential contamination pathways
Solution Approach 2:
The gasket serves multiple functions simultaneously: it provides the environmental seal, incorporates force-sensing capability, and maintains structural integrity. This multi-functionality eliminates the need for additional dedicated sealing interfaces around force sensors, thereby reducing contamination risk while preserving force sensing versatility
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 encapsulated force sensing gasket significantly reduces the incidence of liquid and chemical ingress, ensuring the electronic components remain protected even under harsh conditions, such as water exposure or diving, by minimizing the number of sealing interfaces and using chemically inert materials that are easy to bond with various device components.
Implementation Method 1
The material may be compression molded or injection molded around the force sensing flexible circuitry
Implementation Method 2
The material may be compression molded or injection molded around the force sensing flexible circuitry
Implementation Method 3
The silicone or other compliant gasket material can be selected to be chemically inert and easy to bond to various materials
Implementation Method 4
Molding silicone around the flexible force sensing circuits enables the gasket seal to become more impervious to contaminants including chemical and water ingress
Data Source
AI summary
An elastomeric gasket is disclosed for use in a portable electronic device. The gasket encapsulates flexible circuits which are used to measure force exerted on a cover glass of the device. The gasket reduces the number of layers of material and thus reduces the risk that outside contaminants and liquids may penetrate the gasket layers and enter the portable electronic device and thereby damage the components of the device.