Force Sensing Dome Switch with Integrated FSR Element
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Solution Overview
Problem
Existing dome switches do not simultaneously or nearly simultaneously close or open two separate circuits, nor do they function as a variable resistor controlled by applied force.
Innovation Solution
A force sensing dome switch is configured with a conductive dome and a force-sensing resistor element positioned between the printed circuit board and the dome, allowing the switch to act as a double-pole, double-throw switch and a variable resistor based on applied force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional dome switch is used, then it can close or open a single circuit, but it cannot simultaneously close or open two separate circuits nor function as a variable resistor
Solution Approach 1:
The patent combines a conventional dome switch structure with a force-sensing resistor (FSR) element into a single integrated assembly. The FSR element is positioned between the dome and the circuit board, allowing the same mechanical structure to simultaneously perform switching functions (closing/opening circuits) and variable resistance functions. This merging enables one device to replace what would traditionally require multiple separate components.
Solution Approach 2:
The force-sensing dome switch is designed to perform multiple functions: it acts as a single-pole single-throw switch, a double-pole double-throw switch, and a variable resistor all within one integrated structure. The FSR element provides force-sensitive resistance control while the dome provides mechanical actuation, creating a universal component that can control multiple circuits simultaneously based on the application requirements.
2Adaptability or versatility
If a force-sensing resistor is added to the dome switch structure, then force-sensitive variable resistance is achieved, but the device complexity increases
Solution Approach 1:
The FSR element is integrated into the existing dome switch structure by positioning it between the dome and the circuit board. This merging approach allows the force-sensing functionality to be added without requiring a completely new design, as the FSR element works in conjunction with the existing dome and trace structure to provide both switching and variable resistance functions.
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 force sensing dome switch effectively closes or opens two separate circuits simultaneously and functions as a variable resistor, enhancing control and functionality in applications requiring force-sensitive switching.
Implementation Method 1
force-sensing resistor element is a layer of material whose resistance changes when force is applied
Data Source
AI summary
The force sensing dome switch is configured to simultaneously, or nearly simultaneously, close or open two separate circuits. For one of these circuits, the force sensing dome switch acts as a variable resistor whose value is controlled by applied force. Each force sensing dome switch is disposed upon a printed circuit board (PCB) comprising two separate circuits. An example force sensing dome switch comprises: a conductive dome in conductive contact with a first trace of a first circuit, the conductive dome is configured to make conductive contact with a second trace of the first circuit when pressed down; and a force-sensing resistor element positioned between the PCB and the conductive dome, the force-sensing resistor element overlays a pair of traces of a second circuit and is configured to conductively connect the pair of traces when pressed against the PCB by the conductive dome. The force-sensing resistor element is a layer of material whose resistance changes when force is applied.