Key Assembly Plinth and Recessed Key Mat Design
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Solution Overview
Problem
Film-style key assemblies face issues with keycaps being inadvertently peeled away and poor tactile feel due to the resilient material's increased actuation force and lateral force transfer, leading to rigidity and unwanted interactions between adjacent keys.
Innovation Solution
A key assembly design featuring a keycap with a plinth and a recessed area in the key mat, combined with an elastic layer that is integrally coupled to the key mat, which reduces perpendicular rigidity and improves tactile feel by providing openings and avoiding undue arcage, thus enhancing durability and reducing peeling risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If resilient material conformally tracks the sides of the raised area of the silicone key mat, then the key assembly provides structural support, but the actuation force increases and tactile feel deteriorates
Solution Approach 1:
The resilient material is segmented into discrete regions: conformal tracking regions that follow the raised area contours for structural support, and non-conformal regions with openings that reduce rigidity. This segmentation allows different portions to serve different functions - some providing support while others reduce actuation force.
Solution Approach 2:
Different regions of the resilient material have different conformality characteristics. The material conformally tracks the raised area in regions where structural support is needed, while having non-conformal regions with openings where reduced rigidity is desired for better tactile feel. This local variation in quality resolves the contradiction between support and operability.
2Stability of the object's composition
If resilient material conformally tracks the raised area, then structural integrity is maintained, but lateral force transfer increases causing unwanted interaction between adjacent keys
Solution Approach 1:
The resilient material is divided into conformal and non-conformal regions, with the non-conformal regions containing openings that act as isolation zones. These segmented regions prevent lateral force transfer between adjacent keys while maintaining structural integrity in the conformal areas.
Solution Approach 2:
Material is extracted from the resilient layer to create openings in non-conformal regions. This removal of material creates discontinuities that block lateral force pathways, preventing crosstalk between adjacent key assemblies while preserving the structural framework.
3Reliability
If the keycap rests atop the raised area with conformal resilient material, then the assembly provides stable biasing, but the keycap can be inadvertently peeled away under pulling force
Solution Approach 1:
The resilient material is segmented into conformal regions that provide stable biasing force and non-conformal regions with openings that reduce overall rigidity. This segmentation allows the material to maintain reliable biasing while being less susceptible to peeling forces.
Solution Approach 2:
The conformality parameter of the resilient material is changed from fully conformal to partially non-conformal with openings. This parameter change reduces the material's rigidity and peel resistance while maintaining its biasing function through the conformal regions.
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 results in a more durable and tactile-friendly key assembly with reduced actuation force and minimized lateral crosstalk between keys, improving user experience and assembly reliability.
Implementation Method 1
an elastic layer disposed between the keycap and the contact-responsive switch
Data Source
AI summary
A key assembly comprises a contact-responsive switch and a keycap having a plinth extending from an underside surface thereof. A key mat disposed between the keycap and the contact-responsive switch has a recessed area formed therein. This recessed area is sized and configured to receive the keycap's plinth. If desired, an adhesive can physically adhere the keycap to the key mat. By one approach, the key assembly also comprises a substantially-planar elastic layer disposed between the keycap and the contact-responsive switch. If desired, this elastic layer and the aforementioned key mat are integrally coupled to one another. By one approach this elastic layer has at least one opening disposed therethrough. This opening (or these openings) can be disposed at least in part in common with the aforementioned recessed area of the key mat.