Multi-Character Keycap with Deforming Portions for Thin Device Stability
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Solution Overview
Problem
Modern keypad and keyboard designs for handheld electronic devices face challenges in providing stable, illuminated, and tactilely distinct keys within a thin profile, often resulting in wobbly and prone-to-damage dome switches.
Innovation Solution
A key assembly featuring single-piece keycaps with multiple character-representing portions separated by deforming portions, paired with dome switches and actuators that preload the switches for enhanced stability and tactile feedback, allowing for easier key presses and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If dome switches are used to provide a thinner device profile, then the device thickness is reduced, but the keys become wobbly and unstable
Solution Approach 1:
The keycap is divided into multiple character-representing portions separated by deforming portions, allowing each character to be pressed independently while maintaining overall keycap stability. This segmentation prevents the wobbly behavior of traditional dome switches by distributing the mechanical stress across multiple controlled deformation zones.
Solution Approach 2:
The keycap is formed as a single-piece molded structure combining rigid character portions with flexible deforming portions. This composite construction integrates both stability (rigid portions) and tactile feedback (flexible portions) into one unified component, eliminating the need for separate dome switches that cause instability.
2Length of moving object
If traditional dome switches are used, then the device profile remains thin, but the keys are prone to damage
Solution Approach 1:
The deforming portions are pre-configured with optimal thickness and material properties to provide predetermined tactile feedback and resistance. This preliminary design ensures that each key press follows a controlled deformation path, preventing excessive stress concentration that could lead to damage or failure of the key assembly.
Solution Approach 2:
The keycap utilizes variations in material thickness (parameter) across different regions - thinner in deforming portions for flexibility and tactile feedback, thicker in character portions for durability. This parameter optimization balances durability with the thin profile requirement without compromising reliability.
3Device complexity
If multiple keys are integrated into single keycaps, then the device complexity is reduced, but visual and tactile separation between keys becomes difficult
Solution Approach 1:
The keycap features localized deforming portions with distinct tactile properties (flexibility, resistance) that differ from the rigid character portions. This local quality differentiation provides clear tactile feedback for each character, enabling easy distinction and operation despite the integrated multi-character design.
Solution Approach 2:
The patent introduces tactile dimension (vertical deformation) to differentiate between characters on the same keycap. By creating measurable vertical displacement and resistance variations in the deforming portions, users can distinguish between characters through touch, compensating for the reduced visual separation in integrated keycaps.
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 provides a more stable and durable key assembly with enhanced tactile feedback and illumination, reducing the force required for key presses and improving user experience while maintaining a thin device profile.
Implementation Method 1
In a rest state in which the keycap is not depressed, at least some of the actuators preload at least some of the dome switches by exerting a force upon the dome switches
Implementation Method 2
a plurality of dome switches and a plurality of single-piece keycaps. Each keycap identifies a row of keyboard characters
Data Source
AI summary
A key assembly for use in an electronic device is provided. The key assembly includes a plurality of dome switches, a plurality of single-piece keycaps and plurality of actuators which activate the dome switches. Each single-piece keycap has a plurality of character-representing portions identifying a number of keyboard characters which are separated by deforming portions. Each character-representing portion is associated with a separate one of the plurality of dome switches. Each actuator has a first side which is engaged by one of the character-representing portions of the single-piece keycap and a second side which engages the dome switch associated with that character-representing portion.