Thin Keyboard Assembly Using Direct Dome-to-PCB Stack-Up
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Solution Overview
Problem
The challenge is to reduce the thickness of keyboard assemblies while maintaining their operational strength and longevity, as existing designs often compromise on size and material usage, leading to reduced durability and assembly complexity.
Innovation Solution
The solution involves directly affixing dome switches to a membrane layer, which is then adhered to a printed circuit board (PCB), allowing for a reduced overall stack-up thickness and simplified assembly by eliminating the need for complex linkage structures, and enabling easier installation of dome switches within the keyboard assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the size and quantity of components are reduced to decrease keyboard thickness, then the thickness is reduced, but the strength and operational life are reduced
Solution Approach 1:
The patent combines the dome switch, membrane layer, and PCB into a directly integrated stack-up structure, eliminating intermediate linkage components. This merging reduces the number of parts while maintaining structural integrity through direct adhesion, resolving the contradiction between reduced thickness and maintained strength.
Solution Approach 2:
The patent employs a thin membrane layer as the structural medium that directly couples the dome switch to the PCB. This flexible film enables direct mounting without complex linkages, achieving both reduced thickness and sufficient mechanical strength through the membrane's inherent flexibility and adhesive bonding.
2Reliability
If complex linkage structures are used to support dome switches, then operational stability is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The patent extracts and removes the complex two-part scissor mechanism and linkage structures from the keyboard assembly. By eliminating these intermediate mechanical linkages and directly mounting dome switches to the membrane layer, the design achieves operational stability through simplicity rather than mechanical complexity.
Solution Approach 2:
The patent segments the keyboard into independent key assemblies, each with a dome switch directly mounted on the membrane layer. This segmentation allows each key to function independently without requiring complex inter-connected linkages, simplifying the overall structure while maintaining operational reliability.
3Stability of the object's composition
If traditional multi-layer stack-up is used, then structural integrity is maintained, but assembly time and manufacturing complexity increase
Solution Approach 1:
The patent merges multiple traditional layers (dome switch mounting layer, membrane layer, PCB) into a directly integrated three-layer stack-up where the dome switch adheres directly to the membrane layer, which in turn adheres directly to the PCB. This consolidation maintains structural integrity while reducing assembly steps and manufacturing complexity.
Data Source
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AI summary
Keyboard assemblies having reduced thicknesses and methods of forming the same. A keyboard assembly may include a printed circuit board (PCB) and a single membrane sheet adhered directly to the PCB. The single membrane sheet may substantially cover the PCB. The keyboard assembly may also include a group of dome switches coupled directly to the single membrane sheet. Another keyboard assembly may include a group of conductive pads and a group of membrane pads. Each of the group of membrane pads may be adhered directly to a corresponding one of the group of conductive pads. The keyboard assembly may also include a group of dome switches coupled directly to the membrane pads. Each of the group of dome switches may be coupled directly to a corresponding one of the group of membrane pads.