Membrane Keyboard Circuit Venting for Waterproof Keystrokes
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Solution Overview
Problem
Conventional membrane circuit boards have weak structural strengths due to large-area gas channels, which compromise their waterproof performance and make them susceptible to corrosion when exposed to water, leading to abnormal function and electrical issues with trapped air and high voltage during keystrokes.
Innovation Solution
A four-layered membrane circuit board design with a gas channel in the third membrane substrate, reducing the area of gas channels in the adhesive layers and increasing their structural strength, while providing effective gas exhaust paths to prevent trapped air and electrical issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If large-area gas channels are formed in the upper hydrogel layer and lower hydrogel layer to exhaust compressed gas, then gas exhaust performance is improved, but the structural strength of the hydrogel layers becomes weaker
Solution Approach 1:
The patent introduces a new spatial dimension by adding a fourth membrane substrate layer below the third layer, creating vertical gas channels that extend through multiple layers. This multi-level gas channel architecture allows compressed gas to be exhausted through multiple pathways and dimensions, reducing the burden on any single hydrogel layer and enabling smaller gas channel areas while maintaining effective gas exhaust performance.
2Object-generated harmful factors
If large-area gas channels are formed in the adhesive layers to exhaust compressed gas, then gas exhaust performance is improved, but the waterproof performance deteriorates
Solution Approach 1:
The patent segments the gas exhaust function across multiple adhesive layers and membrane substrates. Instead of forming large gas channels in single adhesive layers, the gas channels are distributed across the first adhesive layer, second adhesive layer, and third adhesive layer, each containing smaller gas channels that collectively provide effective gas exhaust while maintaining the waterproof integrity of individual adhesive layers.
3Reliability
If conductor lines are exposed in the membrane circuit board, then electrical connectivity is achieved, but corrosion susceptibility increases when exposed to water
Solution Approach 1:
The patent employs multiple membrane substrates (first, second, and third membrane substrates) that act as protective flexible shells enclosing the conductor lines and circuit patterns. These membrane substrates form a multi-layer protective barrier that prevents water from reaching the conductor lines while maintaining electrical connectivity through the membrane switches, thereby eliminating corrosion susceptibility.
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
Enhances waterproof performance, protects circuit patterns, and prevents electrical problems caused by trapped air and high voltage, ensuring reliable operation under conditions of rapid keystrokes and high temperature.
Implementation Method 1
some gas channels are formed in the upper hydrogel layer and the lower hydrogel layer. Consequently, the compressed gas can be exited to the surroundings through these gas channels
Data Source
AI summary
A membrane circuit board includes a first membrane substrate, a spacer substrate, a second membrane substrate and a third membrane substrate. The first membrane substrate includes a first gas channel and a first conductive contact. The spacer substrate includes a first gas hole and a second gas hole. The second membrane substrate includes a second gas channel, a second conductive contact, a third gas hole and a fourth gas hole. The second gas channel is in communication with the third gas hole and the fourth gas hole. The second gas channel is in communication with the first gas channel through the first gas hole and the second gas hole. The third membrane substrate includes a third gas channel. The third gas channel is in communication with the second gas channel through the third gas hole and the fourth gas hole.