Pressure-Sensing Membrane Module for Multi-Level Keyboard Input
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Solution Overview
Problem
Existing membrane electronic keyboards can only detect two states of pressing and releasing, limiting their functionality based on different pressing forces, which restricts the range of key functions they can perform.
Innovation Solution
A pressure module comprising a substrate, support structure, and pressing membrane with an electrode and variable resistance layer, where the support structure forms an accommodating cavity, and the electrode and variable resistance layer are positioned on opposite surfaces, allowing the variable resistance layer to change from an insulator to a conductor upon pressure application, enabling adjustable resistance values based on pressure and contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional membrane keyboard structure with key cap, domed silicone elastomer and films is used, then the structure is simple and cost-effective, but it can only detect two states (pressing and releasing) which limits the range of key functions
Solution Approach 1:
The patent changes the detection parameter from binary (pressed/not pressed) to continuous (pressure magnitude). By using a variable resistance layer that changes resistance value according to pressure magnitude, the system can detect different pressing forces and map them to different key functions, thereby increasing adaptability without significantly increasing structural complexity
Solution Approach 2:
The pressure module serves multiple functions: it detects key press events, measures pressing force magnitude, and enables different key functions based on pressure levels. This multi-functional design allows a single structure to replace what would traditionally require multiple separate systems, increasing versatility while maintaining structural simplicity
2Ease of manufacture
If an electrode and variable resistance layer are disposed on opposite surfaces of the substrate and pressing membrane, then the structure remains simple and costs are reduced by using the variable resistance layer as an electrode, but the variable resistance layer must be converted from insulator to conductor upon pressure application
Solution Approach 1:
The patent uses a flexible pressing membrane with a variable resistance layer that can elastically deform under pressure. This thin film structure allows the variable resistance layer to maintain electrical insulation when not pressed, and become conductive when pressed, providing both manufacturing simplicity and reliable electrical contact through the elastic deformation mechanism
Solution Approach 2:
The variable resistance layer acts as an intermediary between the mechanical pressure input and the electrical signal output. It mediates the conversion from mechanical state (pressed/not pressed) to electrical state (insulator/conductor), ensuring reliable signal transmission while maintaining the simplicity of the overall structure
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
This solution allows for controllable adjustment of the pressure module according to applied pressure, enhancing the range of functions that can be performed by the keyboard, while maintaining a simple structure and reducing costs by using the variable resistance layer as an electrode.
Implementation Method 1
on application of pressure to the pressing membrane, the pressing membrane is elastically deformed
Implementation Method 2
a variable resistance layer is respectively disposed on the opposite surface of the other of the substrate and the pressing membrane; wherein on application of pressure to the pressing membrane, the pressing membrane is elastically deformed and the variable resistance layer is brought into contact with the electrode to form a contact area and a resistance value
Data Source
AI summary
A pressure module comprises a substrate, a support structure and a pressing membrane. The support structure is connected to the substrate and the pressing membrane to form an accommodating cavity between the substrate and the pressing membrane. An electrode is disposed on a surface of the substrate or the pressing membrane and a variable resistance layer is respectively disposed on the opposite surface of the other of the substrate and the pressing membrane. On application of pressure to the pressing membrane, the pressing membrane is elastically deformed and the variable resistance layer is brought into contact with the electrode to form a contact area and a resistance value between the variable resistance layer and the electrode. The contact area and the elastic deformation is positively correlated.