Multiple-Sloped Dome Assembly for Enhanced Tactile Feedback
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Solution Overview
Problem
Conventional dome-shaped assemblies in handheld electronic devices often lack noticeable tactile feedback, which is improved with elastomeric or compliant layers, but these increase the thickness and size of the keyboard or keypad.
Innovation Solution
A multiple-sloped dome-shaped element with an annular array of elastic elements, including first and second portions with distinct slopes, is used between a substrate and a laminate, allowing for non-linear tactile response without an elastomeric layer, thereby maintaining a thin profile while enhancing tactile feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If elastomeric or compliant layers are added to the dome assembly, then tactile feedback is improved, but the thickness and size of the keyboard or keypad increase
Solution Approach 1:
The dome assembly is segmented into multiple functional zones: a first region with a first slope providing initial tactile response, a second region with a second slope providing additional tactile feedback, and a third region completing the dome structure. This segmentation allows each region to contribute differently to the tactile experience, providing enhanced feedback without requiring external elastomeric layers that would increase thickness.
Solution Approach 2:
Different regions of the dome assembly are given different local properties through varying slopes and curvatures. The first region has a first slope angle optimized for initial contact feedback, while the second region has a second slope angle optimized for deeper press feedback. This local differentiation of mechanical properties provides enhanced tactile feedback throughout the compression stroke without increasing overall assembly thickness.
2Ease of manufacture
If the dome assembly is made simpler (smooth sector), then manufacturing is easier, but tactile feedback becomes unnoticeable
Solution Approach 1:
Rather than creating a complex multi-component assembly, the invention segments the single dome structure into regions with different geometric properties (slopes, curvatures). This maintains manufacturing simplicity by using a single piece construction while achieving enhanced tactile feedback through geometric variation rather than material or structural complexity.
Solution Approach 2:
The invention changes geometric parameters (slope angles, curvature radii, region boundaries) of the dome assembly to optimize tactile feedback. By adjusting these parameters during the forming process, enhanced tactile response is achieved without changing the fundamental simple dome structure or requiring complex manufacturing methods.
3Ease of operation
If the ramp-up stage is extended for better tactile feel, then tactile feedback is improved, but the travel distance and size of the assembly increase
Solution Approach 1:
The compression stroke is segmented into distinct phases corresponding to different regions of the dome: initial contact with the first region providing first tactile feedback, progression to the second region providing second tactile feedback, and final compression of the third region. This segmentation allows the ramp-up stage to be extended through multiple feedback events rather than requiring a single long travel distance, maintaining compact dimensions.
Solution Approach 2:
The dome assembly provides dynamic tactile feedback throughout the compression stroke rather than a single static response. The varying slopes and curvatures create multiple inflection points in the force-displacement curve, providing ongoing tactile feedback as the user presses deeper. This dynamic response extends the effective ramp-up stage without requiring increased travel distance.
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 non-linear tactile response to pressing forces, extending the ramp-up stage and travel distance, resulting in improved tactile feel without increasing the size of the keyboard assembly, thus maintaining portability and functionality.
Implementation Method 1
The concave surface includes an annular array of elastic elements extending from the center to the periphery. At least one of the elastic elements includes a first portion with a first slope proximate to the center and a second portion with a second slope proximate to the periphery.
Data Source
Figure 1~2
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AI summary
A dome-shaped element 60 disposable in a keyboard of an electronic device is provided. The dome-shaped element includes a concave surface 62 originating at a center 63 and terminating at a periphery 64. The concave surface includes an annular array of elastic elements (65) extending from the center to the periphery. At least one of the elastic elements includes a first portion 66 with a first slope S1 proximate to the center and a second portion 67 with a second slope S2 proximate to the periphery. The concave surface is deflectable between an undeflected position (610) and a deflected position (612) and is configured to affect an operation of the electronic device in the deflected position.