Membrane Switches for Rigid Object Pressure Sensing
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Solution Overview
Problem
Traditional membrane switches are less effective in detecting pressure from rigid objects due to the direct load application, which prevents the membrane layers from bending and contacting each other, reducing their functionality in such scenarios.
Innovation Solution
A pressure-activated membrane switch design featuring a first and second electrically-conductive membrane with spacers and columns that allow deformation and contact upon pressure application, enabling the switch to close the electrical circuit regardless of the object's compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional membrane switches are used with rigid objects, then the structure is simple and economical, but the detection functionality decreases because rigid objects deliver load directly to columns without forming around them
Solution Approach 1:
The membrane layer is segmented into multiple sections with gaps between them, allowing rigid objects to apply pressure to multiple segments simultaneously. This segmentation enables the membrane to deform locally at each gap, facilitating contact between membrane layers even when pressed by rigid objects that cannot conform to the column shape.
Solution Approach 2:
The invention introduces a vertical dimension of deformation by allowing the membrane layer to bend upward toward the first membrane layer when pressure is applied. This dimensional change enables contact between layers in the vertical direction, compensating for the inability of rigid objects to form around columns horizontally.
2Reliability
If membrane layers are designed to bend around rigid columns, then compliant object detection is effective, but rigid object detection fails because the membrane cannot deform sufficiently
Solution Approach 1:
The membrane layer is designed with different local properties: gaps are created at specific locations where pressure application is expected, allowing localized deformation. The portions of the membrane between gaps remain relatively rigid to maintain structural integrity, while the gap regions are designed to deform easily when pressure is applied, enabling reliable contact with the first membrane layer.
Solution Approach 2:
The invention changes the physical parameters of the membrane layer by introducing gaps that alter its stiffness and deformability. The gap size, shape, and distribution are optimized to allow sufficient deformation under pressure from both compliant and rigid objects, while maintaining the membrane's overall structural stability and electrical isolation when not activated.
3Adaptability or versatility
If the membrane layer is made more compliant to detect rigid objects, then rigid object detection improves, but the switch becomes less reliable for compliant objects
Solution Approach 1:
Segmenting the membrane layer into gap-separated sections allows each segment to deform independently when pressure is applied. This segmentation provides mechanical advantage for detecting rigid objects while maintaining the compliance needed for finger detection, as each segment can respond to different types of pressure application without compromising the other.
Solution Approach 2:
The membrane layer with gaps is designed to perform multiple functions: it can detect both compliant objects (fingers) and rigid objects (tools, utensils). The gap structure enables the membrane to adapt its deformation characteristics based on the type of object applied, making the switch universally applicable to different interaction scenarios without requiring separate detection mechanisms.
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 design effectively senses pressure from both compliant and rigid objects by allowing the conductive membranes to contact each other, enhancing the switch's functionality in detecting various types of pressure applications.
Implementation Method 1
when a pressure is applied to the one or more columns, which will cause the second electrically-conductive membrane to deform to contact the first electrically-conductive membrane
Data Source
AI summary
A pressure-activated membrane switch and methods of use are provided. The pressure-activated membrane switch includes a first electrically-conductive membrane, and a second electrically-conductive membrane. Contact between the first electrically-conductive membrane and the second electrically-conductive membrane is configured to cause an electrical circuit, of which the switch is a part, to close. The pressure-activated membrane switch further includes a plurality of spacers dispersed between the first electrically-conductive membrane and the second electrically-conductive membrane, and one or more columns positioned on an outer surface of the second electrically-conductive membrane. The plurality of spacers form one or more gaps between the first electrically-conductive membrane and the second electrically-conductive membrane, and the one or more columns are configured to pass through the one or more gaps when a pressure is applied to the one or more columns, which will cause the second electrically-conductive membrane to deform to contact the first electrically-conductive membrane.