Curable Foam Shims for Electronic Button Assemblies
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Solution Overview
Problem
Conventional button shims in electronic devices often fail to provide a precise tactile feel due to variations in manufactured thickness, leading to either excessive play or preloading, which affects the button's travel range and user experience.
Innovation Solution
The use of curable foam shims that transform from a compressible state to a rigid state upon curing, either shrinking or expanding to adapt to the dimensions of the button assembly, ensuring a precise thickness and enhancing tactile feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional plastic shim with fixed thickness is used, then the manufacturing process is simple, but the tactile feel varies due to thickness variations causing either excessive play or preloading
Solution Approach 1:
The shim material's physical state is changed from rigid to curable foam, allowing the thickness parameter to be adjusted after placement. The foam is cured in situ to achieve the precise final thickness needed, transforming a manufacturing precision problem into a post-assembly adjustment solution.
Solution Approach 2:
The foam shim is placed in its uncured, formable state before the final curing step. This preliminary placement allows the shim to be positioned and then cured to achieve the exact thickness required, ensuring precision without requiring ultra-precise manufacturing tolerances.
2Ease of operation
If the shim thickness is reduced to eliminate gaps, then rattling is prevented, but button travel becomes too short affecting tactile feel
Solution Approach 1:
The shim transitions from a static, pre-determined thickness to a dynamic, adjustable thickness through the curing process. The foam can be compressed during assembly to accommodate varying component dimensions, then cured to lock in the optimal thickness that provides both adequate button travel and gap elimination.
Solution Approach 2:
The foam shim undergoes a phase transition from a soft, compressible state during assembly to a rigid, stable state after curing. This allows the shim to be compressed to the correct thickness during assembly (ensuring adequate button travel) and then locked in place (preventing rattling).
3Object-generated harmful factors
If the shim thickness is increased to fill gaps, then rattling is eliminated, but the button becomes preloaded reducing travel range
Solution Approach 1:
The shim's thickness is made dynamic through the curing process, allowing it to be compressed during assembly to the precise thickness needed. This eliminates the need to over-compensate for thickness variations, ensuring gaps are filled without excessive thickness that would preload the button.
4Reliability
If precise shim thickness is manufactured to accommodate component variations, then tactile feel is consistent, but manufacturing complexity and cost increase
Solution Approach 1:
The shim material's physical state is changed from rigid to curable foam, allowing the thickness parameter to be adjusted after placement. The foam is cured in situ to achieve the precise final thickness needed, transforming a manufacturing precision problem into a post-assembly adjustment solution.
Solution Approach 2:
The foam shim self-adjusts to the correct thickness through the curing process. By placing the foam in its uncured state and then curing it in situ, the shim automatically adapts to the actual dimensions of surrounding components, ensuring consistent tactile feel without requiring complex manufacturing processes.
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 adaptive foam shims provide a consistent and desired tactile feel by filling gaps or adjusting thickness to match the button assembly's components, improving user experience by eliminating rattling or short travel issues.
Implementation Method 1
the foam shim transforms from the compressible state to the rigid state in response ultraviolet curing or curing by heat exposure
Implementation Method 2
the foam shim transforms from the compressible state to the rigid state in response ultraviolet curing or curing by heat exposure
Data Source
AI summary
Button assemblies using curable foam shims are disclosed. A button assembly may include a housing, a button positioned within the housing, and a curable foam shim positioned within the housing, the foam shim transformable between a compressible state having a first thickness, to a rigid state having a second thickness smaller than the first thickness. In this manner, the foam shim can be used to adaptively fill the interior of a button assembly by adapting to the dimensions of various components within the button assembly. In another example, a button assembly is formed using a foam shim by curing from a first state having a first thickness to a second state having a second thickness greater than the first thickness. In this manner, the foam shim can be used to adaptively fill the interior of a button assembly by adapting to the dimensions of various components within the button assembly.