Keyboard Membrane Circuit Board Water Baffling Edge Design
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Solution Overview
Problem
Conventional keyboards with membrane circuit boards are prone to water ingress through holes, leading to unbonding between layers and short-circuit issues due to direct contact with conductive patterns.
Innovation Solution
The keyboard design incorporates a water-baffling edge between the upper and middle membrane layer holes, and a water-baffling layer on top, which prevents water from flowing into the gaps between the membrane layers, enhancing the waterproof function by blocking liquid entry and allowing it to flow out through designated holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If through holes are provided in the membrane circuit board for key assembly, then key assembly is enabled, but water can flow into the interior of the membrane circuit board causing unbonding or short-circuit
Solution Approach 1:
The through hole is segmented into three separate holes through the different membrane layers (upper membrane layer hole, middle membrane layer hole, lower membrane layer hole) rather than being a single continuous hole. This segmentation allows the assembly member to pass through while creating barriers to water flow between layers.
Solution Approach 2:
The assembly member acts as an intermediary element that passes through the segmented holes. Its structure with protrusions fitting into grooves on the base plate creates a mechanical connection while the segmented hole structure prevents water from using the assembly path as a water pathway.
2Ease of manufacture
If gaps exist between membrane layers for layer bonding, then layer assembly is enabled, but water can flow through gaps into the interior causing unbonding or short-circuit
Solution Approach 1:
The continuous gap between layers is segmented by the water-baffling edges that protrude into the gaps at specific locations. These edges create multiple small barriers rather than allowing a continuous water pathway through the gaps.
Solution Approach 2:
The water-baffling edges convert the potential harm of water flowing through gaps into a beneficial barrier function. The edges that would normally be simple structural elements are designed to actively block water while still allowing the gaps to exist for layer assembly and flexibility.
3Adaptability or versatility
If water enters the membrane circuit board, then liquid contact with conductive patterns occurs, but this causes short-circuit and unbonding
Solution Approach 1:
The water-baffling edges act as intermediary barriers between the external water environment and the internal conductive patterns. They intercept water flow before it can reach the conductive patterns, protecting the electrical stability while maintaining keyboard functionality.
Solution Approach 2:
The water-baffling edges perform preliminary anti-action by blocking water flow in advance before it can cause harm to the conductive patterns. The edges are positioned to intercept water at the earliest possible point, preventing short-circuit and unbonding before they can occur.
Data Source
AI summary
A keyboard device includes a substrate, keycaps, and a membrane circuit board. The substrate has an upper surface including assembly areas, and the upper surface has an assembly member. The keycaps are disposed on the substrate and respectively corresponding to the assembly areas. The membrane circuit board is disposed between the substrate and the keycaps. The membrane circuit board includes an upper membrane layer having an upper layer hole, a lower membrane layer having a lower layer hole, and a spacing layer having a middle layer hole. The upper layer hole, the middle layer hole, and the lower layer hole communicate with each other. The assembly member protrudes upwardly from the lower layer hole, the middle layer hole, and the upper layer hole. The upper membrane layer includes a water-baffling edge between edges of the upper layer hole and the middle layer hole.